Kinetis KL25: 48MHz Cortex M0+ 32 128KB Flash 80 Pin KL25Z Reference Manual

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KL25 Sub-Family Reference Manual
Supports: MKL25Z32VFM4, MKL25Z64VFM4, MKL25Z128VFM4,
MKL25Z32VFT4, MKL25Z64VFT4, MKL25Z128VFT4,
MKL25Z32VLH4, MKL25Z64VLH4, MKL25Z128VLH4,
MKL25Z32VLK4, MKL25Z64VLK4, and MKL25Z128VLK4

Document Number: KL25P80M48SF0RM
Rev. 3, September 2012

KL25 Sub-Family Reference Manual, Rev. 3, September 2012
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Freescale Semiconductor, Inc.

Contents
Section number

Title

Page

Chapter 1
About This Document
1.1

1.2

Overview.......................................................................................................................................................................33
1.1.1

Purpose.........................................................................................................................................................33

1.1.2

Audience......................................................................................................................................................33

Conventions..................................................................................................................................................................33
1.2.1

Numbering systems......................................................................................................................................33

1.2.2

Typographic notation...................................................................................................................................34

1.2.3

Special terms................................................................................................................................................34

Chapter 2
Introduction
2.1

Overview.......................................................................................................................................................................35

2.2

Kinetis L Series.............................................................................................................................................................35

2.3

KL25 Sub-Family Introduction.....................................................................................................................................38

2.4

Module functional categories........................................................................................................................................39

2.5

2.4.1

ARM® Cortex™-M0+ Core Modules.........................................................................................................39

2.4.2

System Modules...........................................................................................................................................40

2.4.3

Memories and Memory Interfaces...............................................................................................................41

2.4.4

Clocks...........................................................................................................................................................41

2.4.5

Security and Integrity modules....................................................................................................................42

2.4.6

Analog modules...........................................................................................................................................42

2.4.7

Timer modules.............................................................................................................................................42

2.4.8

Communication interfaces...........................................................................................................................43

2.4.9

Human-machine interfaces..........................................................................................................................44

Orderable part numbers.................................................................................................................................................44

Chapter 3
Chip Configuration
3.1

Introduction...................................................................................................................................................................45
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Section number
3.2

3.3

3.4

3.5

3.6

Title

Page

Module to Module Interconnects..................................................................................................................................45
3.2.1

Module to Module Interconnects.................................................................................................................45

3.2.2

Analog reference options.............................................................................................................................48

Core Modules................................................................................................................................................................48
3.3.1

ARM Cortex-M0+ Core Configuration.......................................................................................................48

3.3.2

Nested Vectored Interrupt Controller (NVIC) Configuration......................................................................51

3.3.3

Asynchronous wake-up interrupt controller (AWIC) configuration............................................................55

System Modules............................................................................................................................................................56
3.4.1

SIM Configuration.......................................................................................................................................56

3.4.2

System Mode Controller (SMC) Configuration...........................................................................................57

3.4.3

PMC Configuration......................................................................................................................................57

3.4.4

Low-Leakage Wake-up Unit (LLWU) Configuration.................................................................................58

3.4.5

MCM Configuration....................................................................................................................................60

3.4.6

Crossbar-Light Switch Configuration..........................................................................................................61

3.4.7

Peripheral Bridge Configuration..................................................................................................................62

3.4.8

DMA request multiplexer configuration......................................................................................................63

3.4.9

DMA Controller Configuration...................................................................................................................66

3.4.10

Computer Operating Properly (COP) Watchdog Configuration..................................................................67

Clock Modules..............................................................................................................................................................70
3.5.1

MCG Configuration.....................................................................................................................................70

3.5.2

OSC Configuration......................................................................................................................................71

Memories and Memory Interfaces................................................................................................................................72
3.6.1

Flash Memory Configuration.......................................................................................................................72

3.6.2

Flash Memory Controller Configuration.....................................................................................................74

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Section number
3.6.3
3.7

3.8

3.9

3.10

Title

Page

SRAM Configuration...................................................................................................................................75

Analog...........................................................................................................................................................................77
3.7.1

16-bit SAR ADC Configuration..................................................................................................................77

3.7.2

CMP Configuration......................................................................................................................................81

3.7.3

12-bit DAC Configuration...........................................................................................................................83

Timers...........................................................................................................................................................................84
3.8.1

Timer/PWM Module Configuration............................................................................................................84

3.8.2

PIT Configuration........................................................................................................................................87

3.8.3

Low-power timer configuration...................................................................................................................88

3.8.4

RTC configuration.......................................................................................................................................90

Communication interfaces............................................................................................................................................91
3.9.1

Universal Serial Bus (USB) FS Subsystem.................................................................................................91

3.9.2

SPI configuration.........................................................................................................................................96

3.9.3

I2C Configuration........................................................................................................................................97

3.9.4

UART Configuration...................................................................................................................................98

Human-machine interfaces (HMI)................................................................................................................................99
3.10.1

GPIO Configuration.....................................................................................................................................99

3.10.2

TSI Configuration........................................................................................................................................101

Chapter 4
Memory Map
4.1

Introduction...................................................................................................................................................................105

4.2

System memory map.....................................................................................................................................................105

4.3

Flash Memory Map.......................................................................................................................................................106
4.3.1

Alternate Non-Volatile IRC User Trim Description....................................................................................106

4.4

SRAM memory map.....................................................................................................................................................107

4.5

Bit Manipulation Engine...............................................................................................................................................107

4.6

Peripheral bridge (AIPS-Lite) memory map.................................................................................................................108
4.6.1

Read-after-write sequence and required serialization of memory operations..............................................108

4.6.2

Peripheral Bridge (AIPS-Lite) Memory Map..............................................................................................109
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Section number
4.6.3
4.7

Title

Page

Modules Restricted Access in User Mode...................................................................................................112

Private Peripheral Bus (PPB) memory map..................................................................................................................112

Chapter 5
Clock Distribution
5.1

Introduction...................................................................................................................................................................115

5.2

Programming model......................................................................................................................................................115

5.3

High-Level device clocking diagram............................................................................................................................115

5.4

Clock definitions...........................................................................................................................................................116
5.4.1

5.5

Device clock summary.................................................................................................................................117

Internal clocking requirements.....................................................................................................................................119
5.5.1

Clock divider values after reset....................................................................................................................119

5.5.2

VLPR mode clocking...................................................................................................................................120

5.6

Clock Gating.................................................................................................................................................................121

5.7

Module clocks...............................................................................................................................................................121
5.7.1

PMC 1-kHz LPO clock................................................................................................................................122

5.7.2

COP clocking...............................................................................................................................................122

5.7.3

RTC clocking...............................................................................................................................................123

5.7.4

LPTMR clocking..........................................................................................................................................123

5.7.5

TPM clocking...............................................................................................................................................124

5.7.6

USB FS OTG Controller clocking...............................................................................................................124

5.7.7

UART clocking............................................................................................................................................125

Chapter 6
Reset and Boot
6.1

Introduction...................................................................................................................................................................127

6.2

Reset..............................................................................................................................................................................127
6.2.1

Power-on reset (POR)..................................................................................................................................128

6.2.2

System reset sources....................................................................................................................................128

6.2.3

MCU Resets.................................................................................................................................................131

6.2.4

Reset Pin .....................................................................................................................................................133

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Section number
6.2.5
6.3

Title

Page

Debug resets.................................................................................................................................................133

Boot...............................................................................................................................................................................134
6.3.1

Boot sources.................................................................................................................................................134

6.3.2

FOPT boot options.......................................................................................................................................134

6.3.3

Boot sequence..............................................................................................................................................135

Chapter 7
Power Management
7.1

Introduction...................................................................................................................................................................137

7.2

Clocking Modes............................................................................................................................................................137
7.2.1

Partial Stop...................................................................................................................................................137

7.2.2

DMA Wakeup..............................................................................................................................................138

7.2.3

Compute Operation......................................................................................................................................139

7.2.4

Peripheral Doze............................................................................................................................................140

7.2.5

Clock Gating................................................................................................................................................141

7.3

Power modes.................................................................................................................................................................141

7.4

Entering and exiting power modes...............................................................................................................................143

7.5

Module Operation in Low Power Modes......................................................................................................................143

Chapter 8
Security
8.1

Introduction...................................................................................................................................................................149

8.2

Flash Security...............................................................................................................................................................149

8.3

Security Interactions with other Modules.....................................................................................................................149
8.3.1

Security Interactions with Debug.................................................................................................................150

Chapter 9
Debug
9.1

Introduction...................................................................................................................................................................151

9.2

Debug Port Pin Descriptions.........................................................................................................................................151

9.3

SWD status and control registers..................................................................................................................................152
9.3.1

MDM-AP Control Register..........................................................................................................................153

9.3.2

MDM-AP Status Register............................................................................................................................154
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Title

Page

9.4

Debug Resets................................................................................................................................................................156

9.5

Micro Trace Buffer (MTB)...........................................................................................................................................157

9.6

Debug in Low Power Modes........................................................................................................................................157

9.7

Debug & Security.........................................................................................................................................................157

Chapter 10
Signal Multiplexing and Signal Descriptions
10.1

Introduction...................................................................................................................................................................159

10.2

Signal Multiplexing Integration....................................................................................................................................159

10.3

10.4

10.2.1

Port control and interrupt module features..................................................................................................160

10.2.2

Clock gating.................................................................................................................................................161

10.2.3

Signal multiplexing constraints....................................................................................................................161

Pinout............................................................................................................................................................................161
10.3.1

KL25 Signal Multiplexing and Pin Assignments........................................................................................161

10.3.2

KL25 Pinouts...............................................................................................................................................164

Module Signal Description Tables................................................................................................................................168
10.4.1

Core Modules...............................................................................................................................................168

10.4.2

System Modules...........................................................................................................................................169

10.4.3

Clock Modules.............................................................................................................................................169

10.4.4

Memories and Memory Interfaces...............................................................................................................169

10.4.5

Analog..........................................................................................................................................................169

10.4.6

Timer Modules.............................................................................................................................................170

10.4.7

Communication Interfaces...........................................................................................................................171

10.4.8

Human-Machine Interfaces (HMI)..............................................................................................................173

Chapter 11
Port control and interrupts (PORT)
11.1

Introduction...................................................................................................................................................................175

11.2

Overview.......................................................................................................................................................................175
11.2.1

Features........................................................................................................................................................175

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11.2.2

Title

Page

Modes of operation......................................................................................................................................176

11.3

External signal description............................................................................................................................................176

11.4

Detailed signal description............................................................................................................................................177

11.5

Memory map and register definition.............................................................................................................................177

11.6

11.5.1

Pin Control Register n (PORTx_PCRn).......................................................................................................183

11.5.2

Global Pin Control Low Register (PORTx_GPCLR)..................................................................................185

11.5.3

Global Pin Control High Register (PORTx_GPCHR).................................................................................186

11.5.4

Interrupt Status Flag Register (PORTx_ISFR)............................................................................................186

Functional description...................................................................................................................................................187
11.6.1

Pin control....................................................................................................................................................187

11.6.2

Global pin control........................................................................................................................................188

11.6.3

External interrupts........................................................................................................................................188

Chapter 12
System integration module (SIM)
12.1

Introduction...................................................................................................................................................................191
12.1.1

12.2

Features........................................................................................................................................................191

Memory map and register definition.............................................................................................................................191
12.2.1

System Options Register 1 (SIM_SOPT1)..................................................................................................193

12.2.2

SOPT1 Configuration Register (SIM_SOPT1CFG)....................................................................................194

12.2.3

System Options Register 2 (SIM_SOPT2)..................................................................................................195

12.2.4

System Options Register 4 (SIM_SOPT4)..................................................................................................197

12.2.5

System Options Register 5 (SIM_SOPT5)..................................................................................................199

12.2.6

System Options Register 7 (SIM_SOPT7)..................................................................................................200

12.2.7

System Device Identification Register (SIM_SDID)...................................................................................202

12.2.8

System Clock Gating Control Register 4 (SIM_SCGC4)............................................................................204

12.2.9

System Clock Gating Control Register 5 (SIM_SCGC5)............................................................................206

12.2.10

System Clock Gating Control Register 6 (SIM_SCGC6)............................................................................207

12.2.11

System Clock Gating Control Register 7 (SIM_SCGC7)............................................................................209

12.2.12

System Clock Divider Register 1 (SIM_CLKDIV1)...................................................................................210
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12.3

Title

Page

12.2.13

Flash Configuration Register 1 (SIM_FCFG1)...........................................................................................211

12.2.14

Flash Configuration Register 2 (SIM_FCFG2)...........................................................................................213

12.2.15

Unique Identification Register Mid-High (SIM_UIDMH)..........................................................................213

12.2.16

Unique Identification Register Mid Low (SIM_UIDML)...........................................................................214

12.2.17

Unique Identification Register Low (SIM_UIDL)......................................................................................214

12.2.18

COP Control Register (SIM_COPC)...........................................................................................................215

12.2.19

Service COP Register (SIM_SRVCOP)......................................................................................................216

Functional description...................................................................................................................................................216

Chapter 13
System Mode Controller (SMC)
13.1

Introduction...................................................................................................................................................................217

13.2

Modes of operation.......................................................................................................................................................217

13.3

Memory map and register descriptions.........................................................................................................................219

13.4

13.3.1

Power Mode Protection register (SMC_PMPROT).....................................................................................219

13.3.2

Power Mode Control register (SMC_PMCTRL).........................................................................................221

13.3.3

Stop Control Register (SMC_STOPCTRL).................................................................................................222

13.3.4

Power Mode Status register (SMC_PMSTAT)...........................................................................................223

Functional description...................................................................................................................................................224
13.4.1

Power mode transitions................................................................................................................................224

13.4.2

Power mode entry/exit sequencing..............................................................................................................227

13.4.3

Run modes....................................................................................................................................................229

13.4.4

Wait modes..................................................................................................................................................231

13.4.5

Stop modes...................................................................................................................................................232

13.4.6

Debug in low power modes.........................................................................................................................235

Chapter 14
Power Management Controller (PMC)
14.1

Introduction...................................................................................................................................................................237

14.2

Features.........................................................................................................................................................................237

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14.3

Title

Page

Low-voltage detect (LVD) system................................................................................................................................237
14.3.1

LVD reset operation.....................................................................................................................................238

14.3.2

LVD interrupt operation...............................................................................................................................238

14.3.3

Low-voltage warning (LVW) interrupt operation.......................................................................................238

14.4

I/O retention..................................................................................................................................................................239

14.5

Memory map and register descriptions.........................................................................................................................239
14.5.1

Low Voltage Detect Status And Control 1 register (PMC_LVDSC1)........................................................240

14.5.2

Low Voltage Detect Status And Control 2 register (PMC_LVDSC2)........................................................241

14.5.3

Regulator Status And Control register (PMC_REGSC)..............................................................................242

Chapter 15
Low-Leakage Wakeup Unit (LLWU)
15.1

Introduction...................................................................................................................................................................245
15.1.1

Features........................................................................................................................................................245

15.1.2

Modes of operation......................................................................................................................................246

15.1.3

Block diagram..............................................................................................................................................247

15.2

LLWU signal descriptions............................................................................................................................................248

15.3

Memory map/register definition...................................................................................................................................248

15.4

15.3.1

LLWU Pin Enable 1 register (LLWU_PE1)................................................................................................249

15.3.2

LLWU Pin Enable 2 register (LLWU_PE2)................................................................................................250

15.3.3

LLWU Pin Enable 3 register (LLWU_PE3)................................................................................................251

15.3.4

LLWU Pin Enable 4 register (LLWU_PE4)................................................................................................252

15.3.5

LLWU Module Enable register (LLWU_ME)............................................................................................253

15.3.6

LLWU Flag 1 register (LLWU_F1).............................................................................................................255

15.3.7

LLWU Flag 2 register (LLWU_F2).............................................................................................................257

15.3.8

LLWU Flag 3 register (LLWU_F3).............................................................................................................258

15.3.9

LLWU Pin Filter 1 register (LLWU_FILT1)..............................................................................................260

15.3.10

LLWU Pin Filter 2 register (LLWU_FILT2)..............................................................................................261

Functional description...................................................................................................................................................262
15.4.1

LLS mode.....................................................................................................................................................263
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Title

Page

15.4.2

VLLS modes................................................................................................................................................263

15.4.3

Initialization.................................................................................................................................................263

Chapter 16
Reset Control Module (RCM)
16.1

Introduction...................................................................................................................................................................265

16.2

Reset memory map and register descriptions...............................................................................................................265
16.2.1

System Reset Status Register 0 (RCM_SRS0)............................................................................................265

16.2.2

System Reset Status Register 1 (RCM_SRS1)............................................................................................267

16.2.3

Reset Pin Filter Control register (RCM_RPFC)..........................................................................................268

16.2.4

Reset Pin Filter Width register (RCM_RPFW)...........................................................................................269

Chapter 17
Bit Manipulation Engine (BME)
17.1

Introduction...................................................................................................................................................................271
17.1.1

Overview......................................................................................................................................................272

17.1.2

Features........................................................................................................................................................272

17.1.3

Modes of Operation.....................................................................................................................................273

17.2

External Signal Description..........................................................................................................................................273

17.3

Memory Map and Register Definition..........................................................................................................................274

17.4

Functional Description..................................................................................................................................................274

17.5

17.4.1

BME Decorated Stores.................................................................................................................................274

17.4.2

BME Decorated Loads.................................................................................................................................280

17.4.3

Additional Details on Decorated Addresses and GPIO Accesses................................................................287

Application Information................................................................................................................................................288

Chapter 18
Miscellaneous Control Module (MCM)
18.1

Introduction...................................................................................................................................................................291
18.1.1

18.2

Features........................................................................................................................................................291

Memory map/register descriptions...............................................................................................................................291
18.2.1

Crossbar Switch (AXBS) Slave Configuration (MCM_PLASC)................................................................292

18.2.2

Crossbar Switch (AXBS) Master Configuration (MCM_PLAMC)............................................................293
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Title

Page

18.2.3

Platform Control Register (MCM_PLACR)................................................................................................293

18.2.4

Compute Operation Control Register (MCM_CPO)...................................................................................296

Chapter 19
Micro Trace Buffer (MTB)
19.1

Introduction...................................................................................................................................................................299
19.1.1

Overview......................................................................................................................................................299

19.1.2

Features........................................................................................................................................................302

19.1.3

Modes of Operation.....................................................................................................................................303

19.2

External Signal Description..........................................................................................................................................303

19.3

Memory Map and Register Definition..........................................................................................................................304
19.3.1

MTB_RAM Memory Map...........................................................................................................................304

19.3.2

MTB_DWT Memory Map...........................................................................................................................316

19.3.3

System ROM Memory Map.........................................................................................................................326

Chapter 20
Crossbar Switch Lite (AXBS-Lite)
20.1

Introduction...................................................................................................................................................................331
20.1.1

Features........................................................................................................................................................331

20.2

Memory Map / Register Definition...............................................................................................................................331

20.3

Functional Description..................................................................................................................................................332

20.4

20.3.1

General operation.........................................................................................................................................332

20.3.2

Arbitration....................................................................................................................................................333

Initialization/application information...........................................................................................................................334

Chapter 21
Peripheral Bridge (AIPS-Lite)
21.1

21.2

Introduction...................................................................................................................................................................335
21.1.1

Features........................................................................................................................................................335

21.1.2

General operation.........................................................................................................................................335

Functional description...................................................................................................................................................336
21.2.1

Access support.............................................................................................................................................336

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Title

Page

Chapter 22
Direct Memory Access Multiplexer (DMAMUX)
22.1

Introduction...................................................................................................................................................................337
22.1.1

Overview......................................................................................................................................................337

22.1.2

Features........................................................................................................................................................338

22.1.3

Modes of operation......................................................................................................................................338

22.2

External signal description............................................................................................................................................339

22.3

Memory map/register definition...................................................................................................................................339
22.3.1

22.4

22.5

Channel Configuration register (DMAMUXx_CHCFGn)..........................................................................339

Functional description...................................................................................................................................................340
22.4.1

DMA channels with periodic triggering capability......................................................................................341

22.4.2

DMA channels with no triggering capability...............................................................................................343

22.4.3

Always-enabled DMA sources....................................................................................................................343

Initialization/application information...........................................................................................................................344
22.5.1

Reset.............................................................................................................................................................344

22.5.2

Enabling and configuring sources................................................................................................................344

Chapter 23
DMA Controller Module
23.1

Introduction...................................................................................................................................................................349
23.1.1

Overview......................................................................................................................................................349

23.1.2

Features........................................................................................................................................................350

23.2

DMA Transfer Overview..............................................................................................................................................351

23.3

Memory Map and Registers..........................................................................................................................................352

23.4

23.3.1

Source Address Register (DMA_SARn).....................................................................................................353

23.3.2

Destination Address Register (DMA_DARn).............................................................................................354

23.3.3

DMA Status Register / Byte Count Register (DMA_DSR_BCRn).............................................................355

23.3.4

DMA Control Register (DMA_DCRn)........................................................................................................357

Functional Description..................................................................................................................................................361
23.4.1

Transfer Requests (Cycle-Steal and Continuous Modes)............................................................................361

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Title

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23.4.2

Channel Initialization and Startup................................................................................................................361

23.4.3

Dual-Address Data Transfer Mode..............................................................................................................363

23.4.4

Advanced Data Transfer Controls: Auto-Alignment...................................................................................364

23.4.5

Termination..................................................................................................................................................365

Chapter 24
Multipurpose Clock Generator (MCG)
24.1

Introduction...................................................................................................................................................................367
24.1.1

Features........................................................................................................................................................367

24.1.2

Modes of Operation.....................................................................................................................................370

24.2

External Signal Description..........................................................................................................................................371

24.3

Memory Map/Register Definition.................................................................................................................................371

24.4

24.3.1

MCG Control 1 Register (MCG_C1)...........................................................................................................372

24.3.2

MCG Control 2 Register (MCG_C2)...........................................................................................................373

24.3.3

MCG Control 3 Register (MCG_C3)...........................................................................................................374

24.3.4

MCG Control 4 Register (MCG_C4)...........................................................................................................374

24.3.5

MCG Control 5 Register (MCG_C5)...........................................................................................................376

24.3.6

MCG Control 6 Register (MCG_C6)...........................................................................................................377

24.3.7

MCG Status Register (MCG_S)..................................................................................................................378

24.3.8

MCG Status and Control Register (MCG_SC)............................................................................................380

24.3.9

MCG Auto Trim Compare Value High Register (MCG_ATCVH)............................................................381

24.3.10

MCG Auto Trim Compare Value Low Register (MCG_ATCVL)..............................................................381

24.3.11

MCG Control 7 Register (MCG_C7)...........................................................................................................382

24.3.12

MCG Control 8 Register (MCG_C8)...........................................................................................................382

24.3.13

MCG Control 9 Register (MCG_C9)...........................................................................................................383

24.3.14

MCG Control 10 Register (MCG_C10).......................................................................................................383

Functional Description..................................................................................................................................................384
24.4.1

MCG mode state diagram............................................................................................................................384

24.4.2

Low Power Bit Usage..................................................................................................................................388

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24.5

Title

Page

24.4.3

MCG Internal Reference Clocks..................................................................................................................388

24.4.4

External Reference Clock............................................................................................................................389

24.4.5

MCG Fixed frequency clock .......................................................................................................................389

24.4.6

MCG PLL clock ..........................................................................................................................................390

24.4.7

MCG Auto TRIM (ATM)............................................................................................................................390

Initialization / Application information........................................................................................................................391
24.5.1

MCG module initialization sequence...........................................................................................................391

24.5.2

Using a 32.768 kHz reference......................................................................................................................393

24.5.3

MCG mode switching..................................................................................................................................394

Chapter 25
Oscillator (OSC)
25.1

Introduction...................................................................................................................................................................405

25.2

Features and Modes......................................................................................................................................................405

25.3

Block Diagram..............................................................................................................................................................406

25.4

OSC Signal Descriptions..............................................................................................................................................406

25.5

External Crystal / Resonator Connections....................................................................................................................407

25.6

External Clock Connections.........................................................................................................................................408

25.7

Memory Map/Register Definitions...............................................................................................................................409
25.7.1

25.8

25.9

OSC Memory Map/Register Definition.......................................................................................................409

Functional Description..................................................................................................................................................410
25.8.1

OSC Module States......................................................................................................................................410

25.8.2

OSC Module Modes.....................................................................................................................................412

25.8.3

Counter.........................................................................................................................................................413

25.8.4

Reference Clock Pin Requirements.............................................................................................................413

Reset..............................................................................................................................................................................414

25.10 Low Power Modes Operation.......................................................................................................................................414
25.11 Interrupts.......................................................................................................................................................................414

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Chapter 26
Flash Memory Controller (FMC)
26.1

Introduction...................................................................................................................................................................415
26.1.1

Overview......................................................................................................................................................415

26.1.2

Features........................................................................................................................................................415

26.2

Modes of operation.......................................................................................................................................................416

26.3

External signal description............................................................................................................................................416

26.4

Memory map and register descriptions.........................................................................................................................416

26.5

Functional description...................................................................................................................................................416

Chapter 27
Flash Memory Module (FTFA)
27.1

Introduction...................................................................................................................................................................419
27.1.1

Features........................................................................................................................................................420

27.1.2

Block Diagram.............................................................................................................................................420

27.1.3

Glossary.......................................................................................................................................................421

27.2

External Signal Description..........................................................................................................................................422

27.3

Memory Map and Registers..........................................................................................................................................422

27.4

27.3.1

Flash Configuration Field Description.........................................................................................................422

27.3.2

Program Flash IFR Map...............................................................................................................................423

27.3.3

Register Descriptions...................................................................................................................................424

Functional Description..................................................................................................................................................432
27.4.1

Flash Protection............................................................................................................................................433

27.4.2

Interrupts......................................................................................................................................................433

27.4.3

Flash Operation in Low-Power Modes........................................................................................................434

27.4.4

Functional Modes of Operation...................................................................................................................434

27.4.5

Flash Reads and Ignored Writes..................................................................................................................434

27.4.6

Read While Write (RWW)...........................................................................................................................435

27.4.7

Flash Program and Erase..............................................................................................................................435

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Title

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27.4.8

Flash Command Operations.........................................................................................................................435

27.4.9

Margin Read Commands.............................................................................................................................440

27.4.10

Flash Command Description........................................................................................................................441

27.4.11

Security........................................................................................................................................................454

27.4.12

Reset Sequence............................................................................................................................................456

Chapter 28
Analog-to-Digital Converter (ADC)
28.1

28.2

28.3

Introduction...................................................................................................................................................................457
28.1.1

Features........................................................................................................................................................457

28.1.2

Block diagram..............................................................................................................................................458

ADC Signal Descriptions..............................................................................................................................................459
28.2.1

Analog Power (VDDA)...............................................................................................................................460

28.2.2

Analog Ground (VSSA)...............................................................................................................................460

28.2.3

Voltage Reference Select.............................................................................................................................460

28.2.4

Analog Channel Inputs (ADx).....................................................................................................................461

28.2.5

Differential Analog Channel Inputs (DADx)...............................................................................................461

Register definition.........................................................................................................................................................461
28.3.1

ADC Status and Control Registers 1 (ADCx_SC1n)...................................................................................462

28.3.2

ADC Configuration Register 1 (ADCx_CFG1)...........................................................................................465

28.3.3

ADC Configuration Register 2 (ADCx_CFG2)...........................................................................................467

28.3.4

ADC Data Result Register (ADCx_Rn).......................................................................................................468

28.3.5

Compare Value Registers (ADCx_CVn).....................................................................................................469

28.3.6

Status and Control Register 2 (ADCx_SC2)................................................................................................470

28.3.7

Status and Control Register 3 (ADCx_SC3)................................................................................................472

28.3.8

ADC Offset Correction Register (ADCx_OFS)...........................................................................................474

28.3.9

ADC Plus-Side Gain Register (ADCx_PG).................................................................................................474

28.3.10

ADC Minus-Side Gain Register (ADCx_MG)............................................................................................475

28.3.11

ADC Plus-Side General Calibration Value Register (ADCx_CLPD).........................................................475

28.3.12

ADC Plus-Side General Calibration Value Register (ADCx_CLPS)..........................................................476
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28.4

Title

Page

28.3.13

ADC Plus-Side General Calibration Value Register (ADCx_CLP4)..........................................................476

28.3.14

ADC Plus-Side General Calibration Value Register (ADCx_CLP3)..........................................................477

28.3.15

ADC Plus-Side General Calibration Value Register (ADCx_CLP2)..........................................................477

28.3.16

ADC Plus-Side General Calibration Value Register (ADCx_CLP1)..........................................................478

28.3.17

ADC Plus-Side General Calibration Value Register (ADCx_CLP0)..........................................................478

28.3.18

ADC Minus-Side General Calibration Value Register (ADCx_CLMD).....................................................479

28.3.19

ADC Minus-Side General Calibration Value Register (ADCx_CLMS).....................................................479

28.3.20

ADC Minus-Side General Calibration Value Register (ADCx_CLM4).....................................................480

28.3.21

ADC Minus-Side General Calibration Value Register (ADCx_CLM3).....................................................480

28.3.22

ADC Minus-Side General Calibration Value Register (ADCx_CLM2).....................................................481

28.3.23

ADC Minus-Side General Calibration Value Register (ADCx_CLM1).....................................................481

28.3.24

ADC Minus-Side General Calibration Value Register (ADCx_CLM0).....................................................482

Functional description...................................................................................................................................................482
28.4.1

Clock select and divide control....................................................................................................................483

28.4.2

Voltage reference selection..........................................................................................................................483

28.4.3

Hardware trigger and channel selects..........................................................................................................484

28.4.4

Conversion control.......................................................................................................................................485

28.4.5

Automatic compare function........................................................................................................................493

28.4.6

Calibration function.....................................................................................................................................494

28.4.7

User-defined offset function........................................................................................................................495

28.4.8

Temperature sensor......................................................................................................................................497

28.4.9

MCU wait mode operation...........................................................................................................................497

28.4.10

MCU Normal Stop mode operation.............................................................................................................498

28.4.11

MCU Low-Power Stop mode operation......................................................................................................499

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Section number
28.5

Page

Initialization information..............................................................................................................................................499
28.5.1

28.6

Title

ADC module initialization example............................................................................................................499

Application information................................................................................................................................................501
28.6.1

External pins and routing.............................................................................................................................501

28.6.2

Sources of error............................................................................................................................................503

Chapter 29
Comparator (CMP)
29.1

Introduction...................................................................................................................................................................509

29.2

CMP features................................................................................................................................................................509

29.3

6-bit DAC key features.................................................................................................................................................510

29.4

ANMUX key features...................................................................................................................................................511

29.5

CMP, DAC and ANMUX diagram...............................................................................................................................511

29.6

CMP block diagram......................................................................................................................................................512

29.7

Memory map/register definitions..................................................................................................................................514

29.8

29.9

29.7.1

CMP Control Register 0 (CMPx_CR0).......................................................................................................514

29.7.2

CMP Control Register 1 (CMPx_CR1).......................................................................................................515

29.7.3

CMP Filter Period Register (CMPx_FPR)...................................................................................................517

29.7.4

CMP Status and Control Register (CMPx_SCR).........................................................................................517

29.7.5

DAC Control Register (CMPx_DACCR)....................................................................................................518

29.7.6

MUX Control Register (CMPx_MUXCR)..................................................................................................519

Functional description...................................................................................................................................................520
29.8.1

CMP functional modes.................................................................................................................................520

29.8.2

Power modes................................................................................................................................................529

29.8.3

Startup and operation...................................................................................................................................530

29.8.4

Low-pass filter.............................................................................................................................................531

CMP interrupts..............................................................................................................................................................533

29.10 DMA support................................................................................................................................................................533
29.11 CMP Asyncrhonous DMA support...............................................................................................................................534
29.12 Digital-to-analog converter...........................................................................................................................................534
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Page

29.13 DAC functional description..........................................................................................................................................535
29.13.1

Voltage reference source select....................................................................................................................535

29.14 DAC resets....................................................................................................................................................................535
29.15 DAC clocks...................................................................................................................................................................535
29.16 DAC interrupts..............................................................................................................................................................536
29.17 CMP Trigger Mode.......................................................................................................................................................536

Chapter 30
12-bit Digital-to-Analog Converter (DAC)
30.1

Introduction...................................................................................................................................................................537

30.2

Features.........................................................................................................................................................................537

30.3

Block diagram...............................................................................................................................................................537

30.4

Memory map/register definition...................................................................................................................................539

30.5

30.4.1

DAC Data Low Register (DACx_DATnL).................................................................................................539

30.4.2

DAC Data High Register (DACx_DATnH)................................................................................................540

30.4.3

DAC Status Register (DACx_SR)...............................................................................................................540

30.4.4

DAC Control Register (DACx_C0).............................................................................................................541

30.4.5

DAC Control Register 1 (DACx_C1)..........................................................................................................542

30.4.6

DAC Control Register 2 (DACx_C2)..........................................................................................................542

Functional description...................................................................................................................................................543
30.5.1

DAC data buffer operation...........................................................................................................................543

30.5.2

DMA operation............................................................................................................................................544

30.5.3

Resets...........................................................................................................................................................544

30.5.4

Low-Power mode operation.........................................................................................................................544

Chapter 31
Timer/PWM Module (TPM)
31.1

Introduction...................................................................................................................................................................547
31.1.1

TPM Philosophy..........................................................................................................................................547

31.1.2

Features........................................................................................................................................................547

31.1.3

Modes of Operation.....................................................................................................................................548

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Section number
31.1.4
31.2

31.3

31.4

Title

Page

Block Diagram.............................................................................................................................................548

TPM Signal Descriptions..............................................................................................................................................549
31.2.1

TPM_EXTCLK — TPM External Clock....................................................................................................549

31.2.2

TPM_CHn — TPM Channel (n) I/O Pin.....................................................................................................550

Memory Map and Register Definition..........................................................................................................................550
31.3.1

Status and Control (TPMx_SC)...................................................................................................................552

31.3.2

Counter (TPMx_CNT).................................................................................................................................553

31.3.3

Modulo (TPMx_MOD)................................................................................................................................554

31.3.4

Channel (n) Status and Control (TPMx_CnSC)...........................................................................................555

31.3.5

Channel (n) Value (TPMx_CnV).................................................................................................................557

31.3.6

Capture and Compare Status (TPMx_STATUS).........................................................................................557

31.3.7

Configuration (TPMx_CONF).....................................................................................................................559

Functional Description..................................................................................................................................................561
31.4.1

Clock Domains.............................................................................................................................................561

31.4.2

Prescaler.......................................................................................................................................................562

31.4.3

Counter.........................................................................................................................................................562

31.4.4

Input Capture Mode.....................................................................................................................................564

31.4.5

Output Compare Mode.................................................................................................................................565

31.4.6

Edge-Aligned PWM (EPWM) Mode...........................................................................................................566

31.4.7

Center-Aligned PWM (CPWM) Mode........................................................................................................568

31.4.8

Registers Updated from Write Buffers........................................................................................................570

31.4.9

DMA............................................................................................................................................................570

31.4.10

Reset Overview............................................................................................................................................571

31.4.11

TPM Interrupts.............................................................................................................................................571

Chapter 32
Periodic Interrupt Timer (PIT)
32.1

Introduction...................................................................................................................................................................573
32.1.1

Block diagram..............................................................................................................................................573

32.1.2

Features........................................................................................................................................................574
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Title

Page

32.2

Signal description..........................................................................................................................................................574

32.3

Memory map/register description.................................................................................................................................575

32.4

32.3.1

PIT Module Control Register (PIT_MCR)..................................................................................................575

32.3.2

PIT Upper Lifetime Timer Register (PIT_LTMR64H)...............................................................................577

32.3.3

PIT Lower Lifetime Timer Register (PIT_LTMR64L)...............................................................................577

32.3.4

Timer Load Value Register (PIT_LDVALn)...............................................................................................578

32.3.5

Current Timer Value Register (PIT_CVALn).............................................................................................578

32.3.6

Timer Control Register (PIT_TCTRLn)......................................................................................................579

32.3.7

Timer Flag Register (PIT_TFLGn)..............................................................................................................580

Functional description...................................................................................................................................................580
32.4.1

General operation.........................................................................................................................................580

32.4.2

Interrupts......................................................................................................................................................582

32.4.3

Chained timers.............................................................................................................................................582

32.5

Initialization and application information.....................................................................................................................582

32.6

Example configuration for chained timers....................................................................................................................583

32.7

Example configuration for the lifetime timer...............................................................................................................584

Chapter 33
Low-Power Timer (LPTMR)
33.1

33.2

Introduction...................................................................................................................................................................587
33.1.1

Features........................................................................................................................................................587

33.1.2

Modes of operation......................................................................................................................................587

LPTMR signal descriptions..........................................................................................................................................588
33.2.1

33.3

Detailed signal descriptions.........................................................................................................................588

Memory map and register definition.............................................................................................................................588
33.3.1

Low Power Timer Control Status Register (LPTMRx_CSR)......................................................................589

33.3.2

Low Power Timer Prescale Register (LPTMRx_PSR)................................................................................590

33.3.3

Low Power Timer Compare Register (LPTMRx_CMR).............................................................................592

33.3.4

Low Power Timer Counter Register (LPTMRx_CNR)...............................................................................592

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Section number
33.4

Title

Page

Functional description...................................................................................................................................................593
33.4.1

LPTMR power and reset..............................................................................................................................593

33.4.2

LPTMR clocking..........................................................................................................................................593

33.4.3

LPTMR prescaler/glitch filter......................................................................................................................593

33.4.4

LPTMR compare..........................................................................................................................................595

33.4.5

LPTMR counter...........................................................................................................................................595

33.4.6

LPTMR hardware trigger.............................................................................................................................596

33.4.7

LPTMR interrupt..........................................................................................................................................596

Chapter 34
Real Time Clock (RTC)
34.1

34.2

34.3

Introduction...................................................................................................................................................................597
34.1.1

Features........................................................................................................................................................597

34.1.2

Modes of operation......................................................................................................................................597

34.1.3

RTC Signal Descriptions.............................................................................................................................597

Register definition.........................................................................................................................................................598
34.2.1

RTC Time Seconds Register (RTC_TSR)...................................................................................................599

34.2.2

RTC Time Prescaler Register (RTC_TPR)..................................................................................................599

34.2.3

RTC Time Alarm Register (RTC_TAR).....................................................................................................600

34.2.4

RTC Time Compensation Register (RTC_TCR).........................................................................................600

34.2.5

RTC Control Register (RTC_CR)................................................................................................................601

34.2.6

RTC Status Register (RTC_SR)..................................................................................................................603

34.2.7

RTC Lock Register (RTC_LR)....................................................................................................................604

34.2.8

RTC Interrupt Enable Register (RTC_IER).................................................................................................605

Functional description...................................................................................................................................................606
34.3.1

Power, clocking, and reset...........................................................................................................................606

34.3.2

Time counter................................................................................................................................................607

34.3.3

Compensation...............................................................................................................................................607

34.3.4

Time alarm...................................................................................................................................................608

34.3.5

Update mode................................................................................................................................................608
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Title

Page

34.3.6

Register lock................................................................................................................................................609

34.3.7

Interrupt........................................................................................................................................................609

Chapter 35
Universal Serial Bus OTG Controller (USBOTG)
35.1

35.2

Introduction...................................................................................................................................................................611
35.1.1

USB..............................................................................................................................................................611

35.1.2

USB On-The-Go..........................................................................................................................................612

35.1.3

USB-FS Features..........................................................................................................................................613

Functional description...................................................................................................................................................613
35.2.1

35.3

35.4

Data Structures.............................................................................................................................................613

Programmers interface..................................................................................................................................................614
35.3.1

Buffer Descriptor Table...............................................................................................................................614

35.3.2

RX vs. TX as a USB target device or USB host..........................................................................................615

35.3.3

Addressing BDT entries...............................................................................................................................616

35.3.4

Buffer Descriptors (BDs).............................................................................................................................616

35.3.5

USB transaction...........................................................................................................................................619

Memory map/Register definitions................................................................................................................................621
35.4.1

Peripheral ID register (USBx_PERID)........................................................................................................623

35.4.2

Peripheral ID Complement register (USBx_IDCOMP)...............................................................................624

35.4.3

Peripheral Revision register (USBx_REV)..................................................................................................624

35.4.4

Peripheral Additional Info register (USBx_ADDINFO).............................................................................625

35.4.5

OTG Interrupt Status register (USBx_OTGISTAT)....................................................................................625

35.4.6

OTG Interrupt Control Register (USBx_OTGICR).....................................................................................626

35.4.7

OTG Status register (USBx_OTGSTAT)....................................................................................................627

35.4.8

OTG Control register (USBx_OTGCTL)....................................................................................................628

35.4.9

Interrupt Status register (USBx_ISTAT).....................................................................................................629

35.4.10

Interrupt Enable register (USBx_INTEN)...................................................................................................630

35.4.11

Error Interrupt Status register (USBx_ERRSTAT).....................................................................................631

35.4.12

Error Interrupt Enable register (USBx_ERREN).........................................................................................632
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Section number

Title

Page

35.4.13

Status register (USBx_STAT)......................................................................................................................633

35.4.14

Control register (USBx_CTL)......................................................................................................................634

35.4.15

Address register (USBx_ADDR).................................................................................................................635

35.4.16

BDT Page Register 1 (USBx_BDTPAGE1)................................................................................................636

35.4.17

Frame Number Register Low (USBx_FRMNUML)...................................................................................636

35.4.18

Frame Number Register High (USBx_FRMNUMH)..................................................................................637

35.4.19

Token register (USBx_TOKEN)..................................................................................................................637

35.4.20

SOF Threshold Register (USBx_SOFTHLD)..............................................................................................638

35.4.21

BDT Page Register 2 (USBx_BDTPAGE2)................................................................................................639

35.4.22

BDT Page Register 3 (USBx_BDTPAGE3)................................................................................................639

35.4.23

Endpoint Control register (USBx_ENDPTn)...............................................................................................639

35.4.24

USB Control register (USBx_USBCTRL)..................................................................................................640

35.4.25

USB OTG Observe register (USBx_OBSERVE)........................................................................................641

35.4.26

USB OTG Control register (USBx_CONTROL)........................................................................................642

35.4.27

USB Transceiver Control Register 0 (USBx_USBTRC0)...........................................................................642

35.4.28

Frame Adjust Register (USBx_USBFRMADJUST)...................................................................................643

35.5

OTG and Host mode operation.....................................................................................................................................644

35.6

Host Mode Operation Examples...................................................................................................................................644

35.7

On-The-Go operation....................................................................................................................................................647
35.7.1

OTG dual role A device operation...............................................................................................................648

35.7.2

OTG dual role B device operation...............................................................................................................649

Chapter 36
USB Voltage Regulator
36.1

36.2

Introduction...................................................................................................................................................................651
36.1.1

Overview......................................................................................................................................................651

36.1.2

Features........................................................................................................................................................652

36.1.3

Modes of Operation.....................................................................................................................................653

USB Voltage Regulator Module Signal Descriptions..................................................................................................653

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Title

Page

Chapter 37
Serial Peripheral Interface (SPI)
37.1

37.2

37.3

37.4

Introduction...................................................................................................................................................................655
37.1.1

Features........................................................................................................................................................655

37.1.2

Modes of Operation.....................................................................................................................................656

37.1.3

Block Diagrams............................................................................................................................................657

External Signal Description..........................................................................................................................................659
37.2.1

SPSCK — SPI Serial Clock.........................................................................................................................659

37.2.2

MOSI — Master Data Out, Slave Data In...................................................................................................660

37.2.3

MISO — Master Data In, Slave Data Out...................................................................................................660

37.2.4

SS — Slave Select........................................................................................................................................660

Memory Map and Register Descriptions......................................................................................................................661
37.3.1

SPI control register 1 (SPIx_C1)..................................................................................................................661

37.3.2

SPI control register 2 (SPIx_C2)..................................................................................................................663

37.3.3

SPI baud rate register (SPIx_BR).................................................................................................................664

37.3.4

SPI status register (SPIx_S).........................................................................................................................665

37.3.5

SPI data register (SPIx_D)...........................................................................................................................667

37.3.6

SPI match register (SPIx_M).......................................................................................................................668

Functional Description..................................................................................................................................................668
37.4.1

General.........................................................................................................................................................668

37.4.2

Master Mode................................................................................................................................................669

37.4.3

Slave Mode..................................................................................................................................................670

37.4.4

SPI Transmission by DMA..........................................................................................................................671

37.4.5

SPI Clock Formats.......................................................................................................................................673

37.4.6

SPI Baud Rate Generation...........................................................................................................................676

37.4.7

Special Features...........................................................................................................................................677

37.4.8

Error Conditions...........................................................................................................................................678

37.4.9

Low Power Mode Options...........................................................................................................................679

37.4.10

Reset.............................................................................................................................................................681
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Section number
37.4.11
37.5

Title

Page

Interrupts......................................................................................................................................................681

Initialization/Application Information..........................................................................................................................683
37.5.1

Initialization Sequence.................................................................................................................................683

37.5.2

Pseudo-Code Example.................................................................................................................................684

Chapter 38
Inter-Integrated Circuit (I2C)
38.1

Introduction...................................................................................................................................................................687
38.1.1

Features........................................................................................................................................................687

38.1.2

Modes of operation......................................................................................................................................688

38.1.3

Block diagram..............................................................................................................................................688

38.2

I2C signal descriptions..................................................................................................................................................689

38.3

Memory map and register descriptions.........................................................................................................................689

38.4

38.3.1

I2C Address Register 1 (I2Cx_A1)..............................................................................................................690

38.3.2

I2C Frequency Divider register (I2Cx_F)....................................................................................................691

38.3.3

I2C Control Register 1 (I2Cx_C1)...............................................................................................................692

38.3.4

I2C Status register (I2Cx_S)........................................................................................................................694

38.3.5

I2C Data I/O register (I2Cx_D)...................................................................................................................695

38.3.6

I2C Control Register 2 (I2Cx_C2)...............................................................................................................696

38.3.7

I2C Programmable Input Glitch Filter register (I2Cx_FLT).......................................................................697

38.3.8

I2C Range Address register (I2Cx_RA)......................................................................................................698

38.3.9

I2C SMBus Control and Status register (I2Cx_SMB).................................................................................699

38.3.10

I2C Address Register 2 (I2Cx_A2)..............................................................................................................701

38.3.11

I2C SCL Low Timeout Register High (I2Cx_SLTH)..................................................................................701

38.3.12

I2C SCL Low Timeout Register Low (I2Cx_SLTL)...................................................................................701

Functional description...................................................................................................................................................702
38.4.1

I2C protocol.................................................................................................................................................702

38.4.2

10-bit address...............................................................................................................................................707

38.4.3

Address matching.........................................................................................................................................709

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38.5

Title

Page

38.4.4

System management bus specification........................................................................................................709

38.4.5

Resets...........................................................................................................................................................712

38.4.6

Interrupts......................................................................................................................................................712

38.4.7

Programmable input glitch filter..................................................................................................................714

38.4.8

Address matching wakeup...........................................................................................................................715

38.4.9

DMA support...............................................................................................................................................715

Initialization/application information...........................................................................................................................716

Chapter 39
Universal Asynchronous Receiver/Transmitter (UART0)
39.1

39.2

39.3

Introduction...................................................................................................................................................................721
39.1.1

Features........................................................................................................................................................721

39.1.2

Modes of operation......................................................................................................................................722

39.1.3

Block diagram..............................................................................................................................................722

Register definition.........................................................................................................................................................724
39.2.1

UART Baud Rate Register High (UARTx_BDH).......................................................................................725

39.2.2

UART Baud Rate Register Low (UARTx_BDL)........................................................................................726

39.2.3

UART Control Register 1 (UARTx_C1).....................................................................................................726

39.2.4

UART Control Register 2 (UARTx_C2).....................................................................................................728

39.2.5

UART Status Register 1 (UARTx_S1)........................................................................................................729

39.2.6

UART Status Register 2 (UARTx_S2)........................................................................................................731

39.2.7

UART Control Register 3 (UARTx_C3).....................................................................................................733

39.2.8

UART Data Register (UARTx_D)...............................................................................................................734

39.2.9

UART Match Address Registers 1 (UARTx_MA1)....................................................................................735

39.2.10

UART Match Address Registers 2 (UARTx_MA2)....................................................................................736

39.2.11

UART Control Register 4 (UARTx_C4).....................................................................................................736

39.2.12

UART Control Register 5 (UARTx_C5).....................................................................................................737

Functional description...................................................................................................................................................738
39.3.1

Baud rate generation....................................................................................................................................738

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Section number

Title

Page

39.3.2

Transmitter functional description...............................................................................................................738

39.3.3

Receiver functional description...................................................................................................................740

39.3.4

Additional UART functions.........................................................................................................................743

39.3.5

Interrupts and status flags............................................................................................................................745

Chapter 40
Universal Asynchronous Receiver/Transmitter (UART1 and UART2)
40.1

40.2

40.3

Introduction...................................................................................................................................................................747
40.1.1

Features........................................................................................................................................................747

40.1.2

Modes of operation......................................................................................................................................747

40.1.3

Block diagram..............................................................................................................................................748

Register definition.........................................................................................................................................................750
40.2.1

UART Baud Rate Register: High (UARTx_BDH)......................................................................................751

40.2.2

UART Baud Rate Register: Low (UARTx_BDL).......................................................................................751

40.2.3

UART Control Register 1 (UARTx_C1).....................................................................................................752

40.2.4

UART Control Register 2 (UARTx_C2).....................................................................................................753

40.2.5

UART Status Register 1 (UARTx_S1)........................................................................................................755

40.2.6

UART Status Register 2 (UARTx_S2)........................................................................................................756

40.2.7

UART Control Register 3 (UARTx_C3).....................................................................................................758

40.2.8

UART Data Register (UARTx_D)...............................................................................................................760

40.2.9

UART Control Register 4 (UARTx_C4).....................................................................................................760

Functional description...................................................................................................................................................761
40.3.1

Baud rate generation....................................................................................................................................761

40.3.2

Transmitter functional description...............................................................................................................762

40.3.3

Receiver functional description...................................................................................................................764

40.3.4

Interrupts and status flags............................................................................................................................767

40.3.5

DMA Operation...........................................................................................................................................768

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Section number
40.3.6

Title

Page

Additional UART functions.........................................................................................................................769

Chapter 41
General-Purpose Input/Output (GPIO)
41.1

41.2

41.3

41.4

Introduction...................................................................................................................................................................771
41.1.1

Features........................................................................................................................................................771

41.1.2

Modes of operation......................................................................................................................................771

41.1.3

GPIO signal descriptions.............................................................................................................................772

Memory map and register definition.............................................................................................................................773
41.2.1

Port Data Output Register (GPIOx_PDOR).................................................................................................775

41.2.2

Port Set Output Register (GPIOx_PSOR)....................................................................................................776

41.2.3

Port Clear Output Register (GPIOx_PCOR)................................................................................................776

41.2.4

Port Toggle Output Register (GPIOx_PTOR).............................................................................................777

41.2.5

Port Data Input Register (GPIOx_PDIR).....................................................................................................777

41.2.6

Port Data Direction Register (GPIOx_PDDR).............................................................................................778

FGPIO memory map and register definition................................................................................................................778
41.3.1

Port Data Output Register (FGPIOx_PDOR)..............................................................................................780

41.3.2

Port Set Output Register (FGPIOx_PSOR).................................................................................................781

41.3.3

Port Clear Output Register (FGPIOx_PCOR).............................................................................................781

41.3.4

Port Toggle Output Register (FGPIOx_PTOR)...........................................................................................782

41.3.5

Port Data Input Register (FGPIOx_PDIR)...................................................................................................782

41.3.6

Port Data Direction Register (FGPIOx_PDDR)..........................................................................................783

Functional description...................................................................................................................................................783
41.4.1

General-purpose input..................................................................................................................................783

41.4.2

General-purpose output................................................................................................................................783

41.4.3

IOPORT.......................................................................................................................................................784

Chapter 42
Touch Sensing Input (TSI)
42.1

Introduction...................................................................................................................................................................785
42.1.1

Features........................................................................................................................................................785

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Section number

42.2

42.4

Page

42.1.2

Modes of operation......................................................................................................................................785

42.1.3

Block diagram..............................................................................................................................................786

External signal description............................................................................................................................................787
42.2.1

42.3

Title

TSI[15:0]......................................................................................................................................................787

Register definition.........................................................................................................................................................787
42.3.1

TSI General Control and Status Register (TSIx_GENCS)..........................................................................787

42.3.2

TSI DATA Register (TSIx_DATA).............................................................................................................792

42.3.3

TSI Threshold Register (TSIx_TSHD)........................................................................................................793

Functional description...................................................................................................................................................793
42.4.1

Capacitance measurement............................................................................................................................794

42.4.2

TSI measurement result...............................................................................................................................797

42.4.3

Enable TSI module.......................................................................................................................................797

42.4.4

Software and hardware trigger.....................................................................................................................797

42.4.5

Scan times....................................................................................................................................................798

42.4.6

Clock setting................................................................................................................................................798

42.4.7

Reference voltage.........................................................................................................................................798

42.4.8

Current source..............................................................................................................................................799

42.4.9

End of scan...................................................................................................................................................799

42.4.10

Out-of-range interrupt..................................................................................................................................799

42.4.11

Wake up MCU from low power modes.......................................................................................................800

42.4.12

DMA function support.................................................................................................................................800

42.4.13

Noise detection mode...................................................................................................................................800

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Chapter 1
About This Document
1.1 Overview
1.1.1 Purpose
This document describes the features, architecture, and programming model of the
Freescale KL25 microcontroller.

1.1.2 Audience
This document is primarily for system architects and software application developers
who are using or considering using the KL25 microcontroller in a system.

1.2 Conventions
1.2.1 Numbering systems
The following suffixes identify different numbering systems:
This suffix

Identifies a

b

Binary number. For example, the binary equivalent of the
number 5 is written 101b. In some cases, binary numbers are
shown with the prefix 0b.

d

Decimal number. Decimal numbers are followed by this suffix
only when the possibility of confusion exists. In general,
decimal numbers are shown without a suffix.

h

Hexadecimal number. For example, the hexadecimal
equivalent of the number 60 is written 3Ch. In some cases,
hexadecimal numbers are shown with the prefix 0x.

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Conventions

1.2.2 Typographic notation
The following typographic notation is used throughout this document:
Example

Description

placeholder, x

Items in italics are placeholders for information that you provide. Italicized text is also used for
the titles of publications and for emphasis. Plain lowercase letters are also used as
placeholders for single letters and numbers.

code

Fixed-width type indicates text that must be typed exactly as shown. It is used for instruction
mnemonics, directives, symbols, subcommands, parameters, and operators. Fixed-width type
is also used for example code. Instruction mnemonics and directives in text and tables are
shown in all caps; for example, BSR.

SR[SCM]

A mnemonic in brackets represents a named field in a register. This example refers to the
Scaling Mode (SCM) field in the Status Register (SR).

REVNO[6:4], XAD[7:0]

Numbers in brackets and separated by a colon represent either:
• A subset of a register's named field
For example, REVNO[6:4] refers to bits 6–4 that are part of the COREREV field that
occupies bits 6–0 of the REVNO register.
• A continuous range of individual signals of a bus
For example, XAD[7:0] refers to signals 7–0 of the XAD bus.

1.2.3 Special terms
The following terms have special meanings:
Term

Meaning

asserted

Refers to the state of a signal as follows:
• An active-high signal is asserted when high (1).
• An active-low signal is asserted when low (0).

deasserted

Refers to the state of a signal as follows:
• An active-high signal is deasserted when low (0).
• An active-low signal is deasserted when high (1).
In some cases, deasserted signals are described as negated.

reserved

Refers to a memory space, register, or field that is either
reserved for future use or for which, when written to, the
module or chip behavior is unpredictable.

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Chapter 2
Introduction
2.1 Overview
This chapter provides an overview of the Kinetis L series of ARM® Cortex™-M0+
MCUs and KL25 product family. It also presents high-level descriptions of the modules
available on the devices covered by this document.

2.2 Kinetis L Series
The Kinetis L series is the most scalable portfolio of ultra low-power, mixed-signal ARM
Cortex-M0+ MCUs in the industry. The portfolio includes 5 MCU families that offer a
broad range of memory, peripheral and package options. Kinetis L Series families share
common peripherals and pin-counts allowing developers to migrate easily within an
MCU family or between MCU families to take advantage of more memory or feature
integration. This scalability allows developers to standardize on the Kinetis L Series for
their end product platforms, maximising hardware and software reuse and reducing timeto-market.
Features common to all Kinetis L series families include:
• 48 MHz ARM Cortex-M0+ core
• High-speed 12/16-bit analog-to-digital converters
• 12-bit digital-to-analog converters for all series except for KLx4/KLx2 family
• High-speed analog comparators
• Low-power touch sensing with wake-up on touch from reduced power states for all
series except for KLx4 family
• Powerful timers for a broad range of applications including motor control
• Low power focused serial communication interfaces such as low power UART, SPI,
I2C etc.
• Single power supply: 1.71V - 3.6V with multiple low-power modes support single
operation temperature: -40 ~ 105 °C (exclude CSP package)

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Kinetis L Series

Kinetis L series MCU families combine the latest low-power innovations with precision
mixed-signal capability and a broad range of communication, connectivity, and humanmachine interface peripherals. Each MCU family is supported by a market-leading
enablement bundle from Freescale and numerous ARM 3rd party ecosystem partners.
The KL0x family is the entry-point to the Kinetis L series and is pin compatible with the
8-bit S08PT family. The KL1x/2x/3x/4x families are compatible with each other and
their equivalent ARM Cortex-M4 Kinetis K series families - K10/20/30/40.
Family

Program
Flash

Packages

KL4x Family 128-256KB

64-121pin

KL3x Family 64-256KB

64-121pin

KL2x Family 32-256KB

32-121pin

KL1x Family 32-256KB

32-80pin

KL0x Family

16-48pin

8-32KB

Low power

Mixed signal

Key Features

USB

Segment LCD

Figure 2-1. Kinetis L series families of MCU portfolio

All Kinetis L series families include a powerful array of analog, communication and
timing and control peripherals with the level of feature integration increasing with flash
memory size and the pin count. Features within the Kinetis L series families include:
• Core and Architecture:
• ARM Cortex-M0+ Core running up to 48 MHz with zero wait state execution
from memories
• Single-cycle access to I/O: Up to 50 percent faster than standard I/O,
improves reaction time to external events allowing bit banging and software
protocol emulation
• Two-stage pipeline: Reduced number of cycles per instruction (CPI),
enabling faster branch instruction and ISR entry, and reducing power
consumption
• Excellent code density vs. 8-bit and 16-bit MCUs - reduces flash size,
system cost and power consumption

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Chapter 2 Introduction

•

•

•

•

• Optimized access to program memory: Accesses on alternate cycles reduces
power consumption
• 100 percent compatible with ARM Cortex-M0 and a subset ARM CortexM3/M4: Reuse existing compilers and debug tools
• Simplified architecture: 56 instructions and 17 registers enables easy
programming and efficient packaging of 8/16/32-bit data in memory
• Linear 4 GB address space removes the need for paging/banking, reducing
software complexity
• ARM third-party ecosystem support: Software and tools to help minimize
development time/cost
• Micro Trace Buffer: Lightweight trace solution allows fast bug identification and
correction
• BME: Bit manipulation engine reduces code size and cycles for bit oriented
operations to peripheral registers eliminating traditional methods where the core
would need to perform read-modify-write operations.
• Up to 4-channel DMA for peripheral and memory servicing with minimal CPU
intervention (feature not available on KL02 family)
Ultra low-power:
• Extreme dynamic efficiency: 32-bit ARM Cortex-M0+ core combined with
Freescale 90 nm thin film storage flash technology delivers 50% energy savings
per Coremark versus the closest 8/16-bit competitive solution
• Multiple flexible low-power modes, including new operation clocking option
which reduces dynamic power by shutting off bus and system clocks for lowest
power core processing. Peripherals with an alternate asynchronous clock source
can continue operation.
• UART, SPI, I2C, ADC, DAC, TPM, LPT, and DMA support low-power mode
operation without waking up the core
Memory:
• Scalable memory footprints from 8 KB flash / 1 KB SRAM to 256 KB flash / 32
KB SRAM
• Embedded 64 B cache memory for optimizing bus bandwidth and flash
execution performance (32 B cache on KL02 family)
Mixed-signal analog:
• Fast, high precision 16-, or 12-bit ADC with optional differential pairs, 12-bit
DAC, high speed comparators. Powerful signal conditioning, conversion and
analysis capability with reduced system cost (12-bit DAC not available on KL02
family)
Human Machine Interface (HMI):
• Optional capacitive Touch Sensing Interface with full low-power support and
minimal current adder when enabled
• Segment LCD controller
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KL25 Sub-Family Introduction

• Connectivity and Communications:
• Up to three UARTs, all UARTs support DMA transfers, and can trigger when
data on bus is detected, UART0 supports 4x to 32x over sampling ratio.
Asynchronous transmit and receive operation for operating in STOP/VLPS
modes.
• Up to two SPIs
• Up to two I2Cs
• Full-speed USB OTG controller with on-chip transceiver
• 5 V to 3.3 V USB on-chip regulator
• One I2S
• Reliability, Safety and Security:
• Internal watchdog with independent clock source
• Timing and Control:
• Powerful timer modules which support general purpose, PWM, and motor
control functions
• Periodic Interrupt Timer for RTOS task scheduler time base or trigger source for
ADC conversion and timer modules
• System:
• GPIO with pin interrupt functionality
• Wide operating voltage range from 1.71 V to 3.6 V with flash programmable
down to 1.71 V with fully functional flash and analog peripherals
• Ambient operating temperature ranges from -40 °C to 105 °C

2.3 KL25 Sub-Family Introduction

The device is highly-integrated, market leading ultra low power 32-bit microcontroller
based on the enhanced Cortex-M0+ (CM0+) core platform. The family derivatives
feature:
• Core platform clock up to 48 MHz, bus clock up to 24 MHz
• Memory option is up to 128 KB Flash and 16 KB RAM
• Wide operating voltage ranges from 1.71V to 3.6V with full functional Flash
program/erase/read operations
• Multiple package options from 32-pin to 80-pin
• Ambient operating temperature ranges from –40 °C to 105 °C
The family acts as an ultra low power, cost effective microcontroller to provide
developers an appropriate entry-level 32-bit solution. The family is next generation MCU
solution for low cost, low power, high performance devices applications. It’s valuable for
cost-sensitive, portable applications requiring long battery life-time.

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Chapter 2 Introduction

2.4 Module functional categories
The modules on this device are grouped into functional categories. The following
sections describe the modules assigned to each category in more detail.
Table 2-1. Module functional categories
Module category

Description

ARM Cortex-M0+ core

• 32-bit MCU core from ARM’s Cortex-M class, 1.77 CoreMark®/MHz from
single-cycle access memories, 48 MHz CPU frequency

System

• System integration module
• Power management and mode controllers
• Multiple power modes available based on run, wait, stop, and powerdown modes
• Miscellaneous control module
• Low-leakage wakeup unit
• Peripheral bridge
• Direct memory access (DMA) controller with multiplexer to increase available
DMA requests
• COP watchdog

Memories

• Internal memories include:
• Up to 128 KB flash memory
• up to 16 KB SRAM

Clocks

• Multiple clock generation options available from internally- and externallygenerated clocks
• MCG module with FLL and PLL for systems and CPU clock sources
• Low power 1 kHz RC oscillator for RTC and COP watchdog
• System oscillator to provide clock source for the MCU

Security

• COP watchdog timer (COP)

Analog

• 16-bit analog-to-digital converters with DMA supported and four muxed
differential pairs
• Comparator (CMP) with internal 6-bit digital-to-analog converter (DAC)
• 12-bit DAC with DMA support and two 16-bit data buffer

Timers

•
•
•
•
•
•

One 6-channel TPM
Two 2-channel TPMs
2-channel periodic interrupt timer
Real time clock
Low-power timer
System tick timer

Communications

•
•
•
•
•

Two 8-bit serial peripheral interface
USB OTG controller with built-in FS/LS transceiver
USB voltage regulator
Two inter-integrated circuit (I2C) modules
One low power UART module and two UART modules

Human-Machine Interfaces (HMI)

• General purpose input/output controller
• Capacitive touch sense input interface enabled in hardware

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Module functional categories

2.4.1 ARM® Cortex™-M0+ Core Modules
The following core modules are available on this device.
Table 2-2. Core modules
Module

Description

ARM® Cortex™-M0+

The ARM® Cortex™-M0+ is the newest member of the Cortex M Series of
processors targeting microcontroller applications focused on very cost sensitive,
deterministic, interrupt driven environments. The Cortex M0+ processor is based
on the ARMv6 Architecture and Thumb®-2 ISA and is 100% instruction set
compatible with its predecessor, the Cortex-M0 core, and upward compatible to
Cortex-M3 and M4 cores.

NVIC

The ARMv6-M exception model and nested-vectored interrupt controller (NVIC)
implement a relocatable vector table supporting many external interrupts, a single
non-maskable interrupt (NMI), and priority levels.
The NVIC replaces shadow registers with equivalent system and simplified
programmability. The NVIC contains the address of the function to execute for a
particular handler. The address is fetched via the instruction port allowing parallel
register stacking and look-up. The first sixteen entries are allocated to ARM
internal sources with the others mapping to MCU-defined interrupts.

AWIC

The primary function of the Asynchronous Wake-up Interrupt Controller (AWIC) is
to detect asynchronous wake-up events in stop modes and signal to clock control
logic to resume system clocking. After clock restart, the NVIC observes the
pending interrupt and performs the normal interrupt or event processing.

Single-cycle I/O Port

For high-speed, single-cycle access to peripherals, the Cortex-M0+ processor
implements a dedicated single-cycle I/O port.

Debug interfaces

Most of this device's debug is based on the ARM CoreSight™ architecture. One
debug interface is supported:
• Serial Wire Debug (SWD)

2.4.2 System Modules
The following system modules are available on this device.
Table 2-3. System modules
Module

Description

System integration module (SIM)

The SIM includes integration logic and several module configuration settings.

System mode controller

The SMC provides control and protection on entry and exit to each power mode,
control for the Power management controller (PMC), and reset entry and exit for
the complete MCU.

Power management controller (PMC)

The PMC provides the user with multiple power options. Multiple modes are
supported that allow the user to optimize power consumption for the level of
functionality needed. Includes power-on-reset (POR) and integrated low voltage
detect (LVD) with reset (brownout) capability and selectable LVD trip points.

Miscellaneous control module (MCM)

The MCM includes integration logic and details.
Table continues on the next page...

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Chapter 2 Introduction

Table 2-3. System modules (continued)
Module

Description

Crossbar switch (XBS)

The XBS connects bus masters and bus slaves, allowing all bus masters to access
different bus slaves simultaneously and providing arbitration among the bus
masters when they access the same slave.

Low-leakage wakeup unit (LLWU)

The LLWU module allows the device to wake from low leakage power modes (LLS
and VLLS) through various internal peripheral and external pin sources.

Peripheral bridge

The peripheral bridge converts the crossbar switch interface to an interface to
access a majority of peripherals on the device.

DMA multiplexer (DMAMUX)

The DMA multiplexer selects from many DMA requests down to 4 for the DMA
controller.

Direct memory access (DMA) controller

The DMA controller provides programmable channels with transfer control
descriptors for data movement via dual-address transfers for 8-, 16- and 32-bit
data values.

Computer operating properly watchdog
(WDOG)

The WDOG monitors internal system operation and forces a reset in case of
failure. It can run from an independent 1 kHz low power oscillator with a
programmable refresh window to detect deviations in program flow or system
frequency.

2.4.3 Memories and Memory Interfaces
The following memories and memory interfaces are available on this device.
Table 2-4. Memories and memory interfaces
Module

Description

Flash memory

Program flash memory — up to 128 KB of the non-volatile flash memory that can
execute program code

Flash memory controller

Manages the interface between the device and the on-chip flash memory.

SRAM

Up to 16 KB internal system RAM.

2.4.4 Clocks
The following clock modules are available on this device.
Table 2-5. Clock modules
Module

Description

Multipurpose Clock Generator (MCG)

MCG module containing a frequency-locked-loop (FLL) and phase-locked-loop
(PLL) controlled by internal or external reference oscillator.

System oscillator

The system oscillator, in conjunction with an external crystal or resonator,
generates a reference clock for the MCU.

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Module functional categories

2.4.5 Security and Integrity modules
The following security and integrity modules are available on this device:
Table 2-6. Security and integrity modules
Module

Description

Watchdog Timer (WDOG)

Watchdog Timer keeps a watch on the system functioning and resets it in case of
its failure.

2.4.6 Analog modules
The following analog modules are available on this device:
Table 2-7. Analog modules
Module

Description

Analog-to-digital converters (ADC)

16-bit successive-approximation ADC module.

Analog comparators

One comparator that compares two analog input voltages across the full range of
the supply voltage and can trigger an ADC acquisition, TPM update, or CPU
interrupt.

6-bit digital-to-analog converters (DAC)

64-tap resistor ladder network which provides a selectable voltage reference for
comparator.

12-bit digital-to-analog converters (DAC) Low-power general-purpose DAC, whose output can be placed on an external pin
or set as one of the inputs to the analog comparator or ADC.

2.4.7 Timer modules
The following timer modules are available on this device:

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Chapter 2 Introduction

Table 2-8. Timer modules
Module

Description

Timer/PWM module (TPM)

• Selectable TPM clock mode
• Prescaler divide-by 1, 2, 4, 8, 16, 32, 64, or 128
• 16-bit free-running counter or modulo counter with counting be up or updown
• Six configurable channels for input capture, output compare, or edge-aligned
PWM mode
• Support the generation of an interrupt and/or DMA request per channel
• Support the generation of an interrupt and/or DMA request when the counter
overflows
• Support selectable trigger input to optionally reset or cause the counter to
start incrementing.
• Support the generation of hardware triggers when the counter overflows and
per channel

Periodic interrupt timers (PIT)

•
•
•
•
•

Low power timer (LPTMR)

• 16-bit time counter or pulse counter with compare
• Configurable clock source for prescaler/glitch filter
• Configurable input source for pulse counter

Real-time counter (RTC)

• 16-bit up-counter
• 16-bit modulo match limit
• Software controllable periodic interrupt on match
• Software selectable clock sources for input to prescaler with programmable
16-bit prescaler
• XOSC 32.678 kHz nominal
• LPO (~1 kHz)
• External RTC_CLKIN

One general purpose interrupt timer
Interrupt timers for triggering ADC conversions
32-bit counter resolution
Clocked by bus clock frequency
DMA support

2.4.8 Communication interfaces
The following communication interfaces are available on this device:
Table 2-9. Communication modules
Module

Description

USB OTG (low-/full-speed)

USB 2.0 compliant module with support for host, device, and On-The-Go modes.
Includes an on-chip transceiver for full and low speeds.

USB voltage regulator

Up to 5 V regulator input typically provided by USB VBUS power with 3.3 V
regulated output that powers on-chip USB subsystem, capable of sourcing 120 mA
to external board components.

Serial peripheral interface (SPI)

Synchronous serial bus for communication to an external device

Inter-integrated circuit (I2C)

Allows communication between a number of devices. Also supports the System
Management Bus (SMBus) Specification, version 2.

Universal asynchronous receiver/
transmitters (UART)

One low power UART module that retains functional in stop modes. Two UART
modules.

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Orderable part numbers

2.4.9 Human-machine interfaces
The following human-machine interfaces (HMI) are available on this device:
Table 2-10. HMI modules
Module

Description

General purpose input/output (GPIO)

Some general purpose input or output (GPIO) pins are capable of interrupt and
DMA request generation.

Capacitive touch sense input (TSI)

Contains up to 16 channel inputs for capacitive touch sensing applications.
Operation is available in low-power modes via interrupts.

2.5 Orderable part numbers
The following table summarizes the part numbers of the devices covered by this
document.
Table 2-11. Orderable part numbers summary
Freescale part number

CPU
frequency

Pin count

Package

Total flash
memory

RAM

Temperature range

MKL25Z32VFM4

48 MHz

32

QFN

32 KB

4 KB

-40 to 105 °C

MKL25Z64VFM4

48 MHz

32

QFN

64 KB

8 KB

-40 to 105 °C

MKL25Z128VFM4

48 MHz

32

QFN

128 KB

16 KB

-40 to 105 °C

MKL25Z32VFT4

48 MHz

48

QFN

32 KB

4 KB

-40 to 105 °C

MKL25Z64VFT4

48 MHz

48

QFN

64 KB

8 KB

-40 to 105 °C

MKL25Z128VFT4

48 MHz

48

QFN

128 KB

16 KB

-40 to 105 °C

MKL25Z32VLH4

48 MHz

64

LQFP

32 KB

4 KB

-40 to 105 °C

MKL25Z64VLH4

48 MHz

64

LQFP

64 KB

8 KB

-40 to 105 °C

MKL25Z128VLH4

48 MHz

64

LQFP

128 KB

16 KB

-40 to 105 °C

MKL25Z32VLK4

48 MHz

80

LQFP

32 KB

4 KB

-40 to 105 °C

MKL25Z64VLK4

48 MHz

80

LQFP

64 KB

8 KB

-40 to 105 °C

MKL25Z128VLK4

48 MHz

80

LQFP

128 KB

16 KB

-40 to 105 °C

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Chapter 3
Chip Configuration
3.1 Introduction
This chapter provides details on the individual modules of the microcontroller. It
includes:
• Module block diagrams showing immediate connections within the device
• Specific module-to-module interactions not necessarily discussed in the individual
module chapters
• Links for more information

3.2 Module to Module Interconnects
3.2.1 Module to Module Interconnects
The below table captures the Module to module interconnections for this device.
Table 3-1. Module to Module Interconnects
Peripheral

Signal

—

to Peripheral

TPM1

CH0F, CH1F

to

ADC (Trigger)

Use Case

Control

ADC Triggering SOPT7_ADCAL
(A AND B)
TTRGEN = 0

Comment
Ch0 is A, and
Ch1 is B,
selecting this
ADC trigger is
for supporting A
and B triggering.
In Stop and
VLPS modes,
the second
trigger must be
set to >10us
after the first
trigger

Table continues on the next page...

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Module to Module Interconnects

Table 3-1. Module to Module Interconnects (continued)
Peripheral

Signal

—

to Peripheral

Use Case

Control

Comment

LPTMR

Hardware trigger

to

ADC (Trigger)

ADC Triggering SOPT7_ADC0T
(A or B)
RGSEL (4 bit
field),
ADC0PRETRG
SEL to select A
or B

—

TPMx

TOF

to

ADC (Trigger)

ADC Triggering SOPT7_ADC0T
(A or B)
RGSEL (4 bit
field),
SOPT7_ADC0P
RETRGSEL to
select A or B

—

PIT CHx

TIF0, TIF1

to

ADC (Trigger)

ADC Triggering SOPT7_ADC0T
(A or B)
RGSEL (4 bit
field),
ADC0PRETRG
SEL to select A
or B

—

RTC

ALARM or
SECONDS

to

ADC (Trigger)

ADC Triggering SOPT7_ADC0T
(A or B)
RGSEL (4 bit
field)
ADC0PRETRG
SEL to select A
or B

—

EXTRG_IN

EXTRG_IN

to

ADC (Trigger)

ADC Triggering SOPT7_ADC0T
(A or B)
RGSEL (4 bit
field)
ADC0PRETRG
SEL to select A
or B

—

CMP0

CMP0_OUT

to

ADC (Trigger)

ADC Triggering SOPT7_ADC0T
(Aor B)
RGSEL (4 bit
field)
ADC0PRETRG
SEL to select A
or B

—

CMP0

CMP0_OUT

to

LPTMR_ALT0

Count CMP
events

LPTMR_CSR[T
PS]

—

CMP0

CMP0_OUT

to

TPM1 CH0

Input capture

SOPT4_TPM1C
H0SRC

—

CMP0

CMP0_OUT

to

TPM2 CH0

Input capture

SOPT4_TPM2C
H0SRC

—

CMP0

CMP0_OUT

to

UART0_RX

IR interface

SOPT5_UART0
RXSRC

—

CMP0

CMP0_OUT

to

UART1_RX

IR Interface

SOPT5_UART1
SRC

—

LPTMR

Hardware trigger

to

CMPx

Low power
CMP_CR1[TRIG
triggering of the
M]
comparator

—

Table continues on the next page...

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Chapter 3 Chip Configuration

Table 3-1. Module to Module Interconnects (continued)
Peripheral

Signal

—

to Peripheral

Use Case

Control

Comment

LPTMR

Hardware trigger

to

TPMx

TPM Trigger
input

TPMx_CONF[T
RGSEL] (4 bit
field)

—

TPMx

TOF

to

TPMx

TPM Trigger
input

TPMx_CONF[T
RGSEL] (4 bit
field)

—

TPM1

Timebase

to

TPMx

TPM Global
timebase input

TPMx_CONF[G
TBEEN]

—

PIT CHx

TIF0, TIF1

to

TPMx

TPM Trigger
input

TPMx_CONF[T
RGSEL] (4 bit
field)

If PIT is
triggering the
TPM, the TPM
clock must be
faster than Bus
clock.

RTC

ALARM or
SECONDS

to

TPMx

TPM Trigger
input

TPMx_CONF[T
RGSEL] (4 bit
field)

—

EXTRG_IN

EXTRG_IN

to

TPMx

TPM Trigger
input

TPMx_CONF[T
RGSEL] (4 bit
field)

—

CMP0

CMP0_OUT

to

TPMx

TPM Trigger
input

TPMx_CONF[T
RGSEL] (4 bit
field)

—

LPTMR

Hardware trigger

to

TSI

TSI triggering

TSI selects HW
trigger

—

UART0

UART0_TX

to

Modulated by
TPM1 CH0

UART
modulation

SOPT5_UART0
TXSRC

—

UART0

UART0_TX

to

Modulated by
TPM2 CH0

UART
modulation

SOPT5_UART0
TXSRC

—

UART1

UART1_TX

to

Modulated by
TPM1 CH0

UART
modulation

SOPT5_UART1
TXSRC

—

UART1

UART1_TX

to

Modulated by
TPM2 CH0

UART
modulation

SOPT5_UART1
TXSRC

—

PIT

TIF0

to

DAC

Advance DAC
FIFO

DAC HWTRG
Select

—

PIT

TIF0

to

DMA CH0

DMA HW
Trigger

DMA MUX
register option

—

PIT

TIF1

to

DMA CH1

DMA HW
Trigger

DMA MUX
register option

—

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Core Modules

3.2.2 Analog reference options
Several analog blocks have selectable reference voltages as shown in the below table.
These options allow analog peripherals to share or have separate analog references. Care
should be taken when selecting analog references to avoid cross talk noise.
Table 3-2. Analog reference options
Module

Reference option

Comment/ Reference selection

16-bit SAR ADC

1 - VREFH

Selected by ADCx_SC2[REFSEL] bits

2 - VDDA
3 - Reserved
12-bit DAC

1 - VREFH
2-

CMP with 6-bit DAC

Selected by DACx_C0[DACRFS] bit

VDDA1

Vin1 - VREFH
Vin2 -

Selected by CMPx_DACCR[VRSEL] bit

VDD1

1. Use this option for the best ADC operation.

3.3 Core Modules
3.3.1 ARM Cortex-M0+ Core Configuration
This section summarizes how the module has been configured in the chip. Full
documentation for this module is provided by ARM and can be found at www.arm.com.

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Chapter 3 Chip Configuration

Debug

Crossbar
switch

Interrupts

ARM Cortex-M0+
Core

Figure 3-1. Core configuration
Table 3-3. Reference links to related information
Topic

Related module

Reference

Full description

ARM Cortex-M0+ core,
r0p0

ARM Cortex-M0+ Technical Reference Manual, r0p0

System memory map

System memory map

Clocking

Clock distribution

Power management

Power management

System/instruction/data
bus module

Crossbar switch

Crossbar switch

Debug

Serial Wire Debug
(SWD)

Debug

Interrupts

Nested Vectored
Interrupt Controller
(NVIC)

NVIC

Miscellaneous Control
Module (MCM)

MCM

3.3.1.1 ARM Cortex M0+ Core
The ARM Cortex M0+ parameter settings are as follows:
Table 3-4. Table 3. ARM Cortex-M0+ parameter settings
Parameter

Verilog Name

Value

Description

Arch Clock Gating

ACG

1 = Present

Implements architectural clock
gating

DAP Slave Port Support

AHBSLV

1

Support any AHB debug
access port (like the CM4
DAP)

DAP ROM Table Base

BASEADDR

0xF000_2003

Base address for DAP ROM
table

Table continues on the next page...

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Core Modules

Table 3-4. Table 3. ARM Cortex-M0+ parameter settings (continued)
Parameter

Verilog Name

Value

Description

Endianess

BE

0

Little endian control for data
transfers

Breakpoints

BKPT

2

Implements 2 breakpoints

Debug Support

DBG

1 = Present

Halt Event Support

HALTEV

1 = Present

I/O Port

IOP

1 = Present

Implements single-cycle ld/st
accesses to special addr
space

IRQ Mask Enable

IRQDIS

0x00000000

Assume (for now) all 32 IRQs
are used (set if IRQ is
disabled)

Debug Port Protocol

JTAGnSW

0 = SWD

SWD protocol, not JTAG

Core Memory Protection

MPU

0 = Absent

No MPU

Number of IRQs

NUMIRQ

32

Assume full NVIC request
vector

Reset all regs

RAR

0 = Standard

Do not force all registers to be
async reset

Multiplier

SMUL

0 = Fast Mul

Implements single-cycle
multiplier

Multi-drop Support

SWMD

0 = Absent

Do not include serial wire
support for multi-drop

System Tick Timer

SYST

1 = Present

Implements system tick timer
(for CM4 compatibility)

DAP Target ID

TARGETID

0

User/Privileged

USER

1 = Present

Implements processor
operating modes

Vector Table Offset Register

VTOR

1 = Present

Implements relocation of
exception vector table

WIC Support

WIC

1 = Present

Implements WIC interface

WIC Requests

WICLINES

34

Exact number of wakeup
IRQs is 34

Watchpoints

WPT

2

Implements 2 watchpoints

For details on the ARM Cortex-M0+ processor core see the ARM website: arm.com.

3.3.1.2 Buses, Interconnects, and Interfaces
The ARM Cortex-M0+ core has two bus interfaces:
• single 32-bit AMBA-3 AHB-Lite system interface that provides connections to
peripherals and all system memory, which includes flash and RAM.
• single 32-bit I/O port bus interfacing to the GPIO with 1-cycle loads and stores.

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Chapter 3 Chip Configuration

3.3.1.3 System Tick Timer
The CLKSOURCE bit in SysTick Control and Status register selects either the core clock
(when CLKSOURCE = 1) or a divide-by-16 of the core clock (when CLKSOURCE = 0).
Because the timing reference is a variable frequency, the TENMS bit in the SysTick
Calibration Value Register is always zero.

3.3.1.4 Debug Facilities
This device supports standard ARM 2-pin SWD debug port.

3.3.1.5 Core Privilege Levels
The Core on this device is implemented with both Privileged and Unprivileged levels.
The ARM documentation uses different terms than this document to distinguish between
privilege levels.
If you see this term...

it also means this term...

Privileged

Supervisor

Unprivileged or user

User

3.3.2 Nested Vectored Interrupt Controller (NVIC) Configuration

ARM Cortex-M0+
core

This section summarizes how the module has been configured in the chip. Full
documentation for this module is provided by ARM and can be found at www.arm.com.
Interrupts

Module

Nested Vectored
Interrupt Controller
(NVIC)

PPB

Module

Module

Figure 3-2. NVIC configuration
Table 3-5. Reference links to related information
Topic

Related module

Reference

Full description

Nested Vectored
Interrupt Controller
(NVIC)

ARM Cortex-M0+ Technical Reference Manual

Table continues on the next page...

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Core Modules

Table 3-5. Reference links to related information (continued)
Topic

Related module

Reference

System memory map

System memory map

Clocking

Clock distribution

Power management

Power management

Private Peripheral Bus
(PPB)

ARM Cortex-M0+ core

ARM Cortex-M0+ core

3.3.2.1 Interrupt priority levels
This device supports 4 priority levels for interrupts. Therefore, in the NVIC each source
in the IPR registers contains 2 bits. For example, IPR0 is shown below:
31

R
W

30

IRQ3

29

28

27

26

25

24

0

0

0

0

0

0

23

22

IRQ2

21

20

19

18

17

16

0

0

0

0

0

0

15

14

IRQ1

13

12

11

10

9

8

0

0

0

0

0

0

7

6

IRQ0

5

4

3

2

1

0

0

0

0

0

0

0

3.3.2.2 Non-maskable interrupt
The non-maskable interrupt request to the NVIC is controlled by the external NMI signal.
The pin the NMI signal is multiplexed on, must be configured for the NMI function to
generate the non-maskable interrupt request.

3.3.2.3 Interrupt channel assignments
The interrupt vector assignments are defined in the following table.
• Vector number — the value stored on the stack when an interrupt is serviced.
• IRQ number — non-core interrupt source count, which is the vector number minus
16.
The IRQ number is used within ARM's NVIC documentation.
Table 3-7. Interrupt vector assignments
Address

Vector

IRQ1

NVIC
IPR
register
number2

Source module

Source description

ARM Core System Handler Vectors
Table continues on the next page...

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Chapter 3 Chip Configuration

Table 3-7. Interrupt vector assignments (continued)
Address

IRQ1

Vector

NVIC
IPR
register
number2

Source module

Source description

0x0000_0000

0

—

—

ARM core

Initial Stack Pointer

0x0000_0004

1

—

—

ARM core

Initial Program Counter

0x0000_0008

2

—

—

ARM core

Non-maskable Interrupt (NMI)

0x0000_000C

3

—

—

ARM core

Hard Fault

0x0000_0010

4

—

—

—

—

0x0000_0014

5

—

—

—

—

0x0000_0018

6

—

—

—

—

0x0000_001C

7

—

—

—

—

0x0000_0020

8

—

—

—

—

0x0000_0024

9

—

—

—

—

0x0000_0028

10

—

—

—

—

0x0000_002C

11

—

—

ARM core

Supervisor call (SVCall)

0x0000_0030

12

—

—

—

—

0x0000_0034

13

—

—

—

—

0x0000_0038

14

—

—

ARM core

Pendable request for system service
(PendableSrvReq)

0x0000_003C

15

—

—

ARM core

System tick timer (SysTick)

0x0000_0040

16

0

0

DMA

DMA channel 0 transfer complete and error

0x0000_0044

17

1

0

DMA

DMA channel 1 transfer complete and error

0x0000_0048

18

2

0

DMA

DMA channel 2 transfer complete and error

0x0000_004C

19

3

0

DMA

DMA channel 3 transfer complete and error

0x0000_0050

20

4

1

—

—

0x0000_0054

21

5

1

FTFA

Command complete and read collision

0x0000_0058

22

6

1

PMC

Low-voltage detect, low-voltage warning

0x0000_005C

23

7

1

LLWU

Low Leakage Wakeup

Non-Core Vectors

0x0000_0060

24

8

2

I2C0

0x0000_0064

25

9

2

I2C1

0x0000_0068

26

10

2

SPI0

Single interrupt vector for all sources

0x0000_006C

27

11

2

SPI1

Single interrupt vector for all sources

0x0000_0070

28

12

3

UART0

Status and error

0x0000_0074

29

13

3

UART1

Status and error

0x0000_0078

30

14

3

UART2

Status and error

0x0000_007C

31

15

3

ADC0

0x0000_0080

32

16

4

CMP0

0x0000_0084

33

17

4

TPM0

0x0000_0088

34

18

4

TPM1

0x0000_008C

35

19

4

TPM2

Table continues on the next page...

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Core Modules

Table 3-7. Interrupt vector assignments (continued)
Address

IRQ1

Vector

NVIC
IPR
register
number2

Source module

Source description

0x0000_0090

36

20

5

RTC

Alarm interrupt

0x0000_0094

37

21

5

RTC

Seconds interrupt

0x0000_0098

38

22

5

PIT

Single interrupt vector for all channels

0x0000_009C

39

23

5

—

—

0x0000_00A0

40

24

6

USB OTG

0x0000_00A4

41

25

6

DAC0

0x0000_00A8

42

26

6

TSI0

0x0000_00AC

43

27

6

MCG

0x0000_00B0

44

28

7

LPTMR0

0x0000_00B4

45

29

7

—

0x0000_00B8

46

30

7

Port control module

Pin detect (Port A)

0x0000_00BC

47

31

7

Port control module

Pin detect ( Port D )

1. Indicates the NVIC's interrupt source number.
2. Indicates the NVIC's IPR register number used for this IRQ. The equation to calculate this value is: IRQ div 4

3.3.2.3.1

Determining the bitfield and register location for configuring a
particular interrupt

Suppose you need to configure the SPI0 interrupt. The following table is an excerpt of the
SPI0 row from Interrupt priority levels.
Table 3-8. Interrupt vector assignments
Address

0x0000_0068

IRQ1

Vector

26

10

NVIC IPR
register
number2
2

Source module

SPI0

Source description

Single interrupt vector for all sources

1. Indicates the NVIC's interrupt source number.
2. Indicates the NVIC's IPR register number used for this IRQ. The equation to calculate this value is: IRQ div 4.

• The NVIC registers you would use to configure the interrupt are:
• NVICIPR2
• To determine the particular IRQ's bitfield location within these particular registers:
• NVICIPR2 bitfield starting location = 8 * (IRQ mod 4) + 6 = 22
Since the NVICIPR bitfields are 2-bit wide (4 priority levels), the NVICIPR2 bitfield
range is 22-23
Therefore, the following bitfield locations are used to configure the SPI0 interrupts:
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Chapter 3 Chip Configuration

• NVICIPR2[23:22]

3.3.3 Asynchronous wake-up interrupt controller (AWIC)
configuration
This section summarizes how the module has been configured in the chip. Full
documentation for this module is provided by ARM and can be found at www.arm.com.
Clock logic

Nested vectored
interrupt controller
(NVIC)

Wake-up
requests

Asynchronous
Wake-up Interrupt
Controller (AWIC)

Module

Module

Figure 3-3. Asynchronous wake-up interrupt controller configuration
Table 3-9. Reference links to related information
Topic

Related module

Reference

System memory map

System memory map

Clocking

Clock distribution

Power management

Power management
Nested vectored
interrupt controller
(NVIC)

Wake-up requests

NVIC

AWIC wake-up sources

3.3.3.1 Wake-up sources
The device uses the following internal and external inputs to the AWIC module.
Table 3-10. AWIC stop wake-up sources
Wake-up source

Description

Available system resets

RESET pin when LPO is its clock source

Low-voltage detect

Mode Controller

Low-voltage warning

Mode Controller

Pin interrupts

Port control module - Any enabled pin interrupt is capable of waking the system

ADC

The ADC is functional when using internal clock source
Table continues on the next page...

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System Modules

Table 3-10. AWIC stop wake-up sources (continued)
Wake-up source

Description

CMP0

Interrupt in normal or trigger mode

I2Cx

Address match wakeup

UART0

Any interrupt provided clock remains enabled

UART1 and UART2

Active edge on RXD

RTC

Alarm or seconds interrupt

TSI

Any interrupt

NMI

NMI pin

TPMx

Any interrupt provided clock remains enabled

LPTMR

Any interrupt provided clock remains enabled

SPI

Slave mode interrupt

3.4 System Modules
3.4.1 SIM Configuration
This section summarizes how the module has been configured in the chip. For a
comprehensive description of the module itself, see the module’s dedicated chapter.
Peripheral
bridge
Register
access

System integration
module (SIM)

Figure 3-4. SIM configuration
Table 3-11. Reference links to related information
Topic

Related module

Reference

Full description

SIM

SIM

System memory map

System memory map

Clocking

Clock distribution

Power management

Power management

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Chapter 3 Chip Configuration

3.4.2 System Mode Controller (SMC) Configuration
This section summarizes how the module has been configured in the chip. For a
comprehensive description of the module itself, see the module’s dedicated chapter.
Peripheral
bridge

Resets

System Mode
Controller (SMC)

Power Management
Controller (PMC)

Register
access

Figure 3-5. System Mode Controller configuration
Table 3-12. Reference links to related information
Topic

Related module

Reference

Full description

System Mode
Controller (SMC)

SMC

System memory map

System memory map

Power management

Power management
Power management
controller (PMC)

PMC

Low-Leakage Wakeup
Unit (LLWU)

LLWU

Reset Control Module
(RCM)

Reset

3.4.2.1 VLLS2 not supported
VLLS2 power mode is not supported on this device.

3.4.3 PMC Configuration
This section summarizes how the module has been configured in the chip. For a
comprehensive description of the module itself, see the module’s dedicated chapter.

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System Modules
Peripheral
bridge

Module
signals

Power Management
Controller (PMC)

Module
signals

System Mode
Controller (SMC)

Low-Leakage
Wakeup Unit

Register access

Figure 3-6. PMC configuration
Table 3-13. Reference links to related information
Topic

Related module

Reference

Full description

PMC

PMC

System memory map

System memory map

Power management

Power management

Full description

System Mode
Controller (SMC)

System Mode Controller

Low-Leakage Wakeup
Unit (LLWU)

LLWU

Reset Control Module
(RCM)

Reset

3.4.4 Low-Leakage Wake-up Unit (LLWU) Configuration
This section summarizes how the module has been configured in the chip. For a
comprehensive description of the module itself, see the module’s dedicated chapter.

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Chapter 3 Chip Configuration
Peripheral
bridge 0

Power Management
Controller (PMC)

Register
access
Wake-up
requests

Low-Leakage Wake-up
Unit (LLWU)

Module

Module

Figure 3-7. Low-Leakage Wake-up Unit configuration
Table 3-14. Reference links to related information
Topic

Related module

Reference

Full description

LLWU

LLWU

System memory map

System memory map

Clocking

Clock distribution

Power management

Power management chapter
Power Management
Controller (PMC)

Power Management Controller (PMC)

System Mode
Controller (SMC)

System Mode Controller

Wake-up requests

LLWU wake-up sources

3.4.4.1 LLWU interrupt
NOTE
Do not mask the LLWU interrupt when in LLS mode. Masking
the interrupt prevents the device from exiting stop mode when a
wakeup is detected.

3.4.4.2 Wake-up Sources
The device uses the following internal peripheral and external pin inputs as wakeup
sources to the LLWU module. LLWU_Px are external pin inputs, and LLWU_M0IFM7IF are connections to the internal peripheral interrupt flags.
NOTE
In addition to the LLWU wakeup sources, the device also
wakes from low power modes when NMI or RESET pins are
enabled and the respective pin is asserted.
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System Modules

Table 3-15. Wakeup Sources
LLWU pin

Module source or pin name

LLWU_P5

PTB0

LLWU_P6

PTC1

LLWU_P7

PTC3

LLWU_P8

PTC4

LLWU_P9

PTC5

LLWU_P10

PTC6

LLWU_P14

PTD4

LLWU_P15

PTD6

LLWU_M0IF

LPTMR0

LLWU_M1IF

CMP0

LLWU_M2IF

Reserved

LLWU_M3IF

Reserved

LLWU_M4IF

TSI0

LLWU_M5IF

RTC Alarm

LLWU_M6IF

Reserved

LLWU_M7IF

RTC Seconds

3.4.5 MCM Configuration

Miscellaneous
Control Module
(MCM)

Transfers

Transfers

Flash Memory
Controller

ARM Cortex-M0+
core

This section summarizes how the module has been configured in the chip. For a
comprehensive description of the module itself, see the module’s dedicated chapter.

Figure 3-8. MCM configuration
Table 3-16. Reference links to related information
Topic

Related module

Reference

Full description

Miscellaneous control
module (MCM)

MCM

System memory map

System memory map

Clocking

Clock distribution

Power management

Power management

Private Peripheral Bus
(PPB)

ARM Cortex-M0+ core

ARM Cortex-M0+ core

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Chapter 3 Chip Configuration

Table 3-16. Reference links to related information (continued)
Topic

Related module

Reference

Transfer

Flash memory
controller

Flash memory controller

3.4.6 Crossbar-Light Switch Configuration
This section summarizes how the module has been configured in the chip. For a
comprehensive description of the module itself, see the module’s dedicated chapter.
GPIO
controller

Crossbar Switch
S0

Flash
controller

M0

ARM core
unified bus

SRAML
S1

M2

DMA

SRAMU

Master Modules

BME

S2

M3

USB

Peripheral
bridge 0

Peripherals

Slave Modules

Figure 3-9. Crossbar-Light switch integration
Table 3-17. Reference links to related information
Topic

Related module

Reference

Full description

Crossbar switch

Crossbar Switch

System memory map

System memory map

Clocking

Clock Distribution

Crossbar switch master ARM Cortex-M0+ core
Crossbar switch master

ARM Cortex-M0+ core

DMA controller

DMA controller

Crossbar switch master

USB FS/LS

USB FS/LS

Crossbar switch slave

Flash memory
controller

Flash memory controller

Crossbar switch slave

SRAM controller

SRAM configuration

Table continues on the next page...

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System Modules

Table 3-17. Reference links to related information (continued)
Topic

Related module

Reference

Crossbar switch slave

Peripheral bridge

Peripheral bridge

2-ported peripheral

GPIO controller

GPIO controleer

3.4.6.1 Crossbar-Light Switch Master Assignments
The masters connected to the crossbar switch are assigned as follows:
Master module

Master port number

ARM core unified bus

0

DMA

2

USB OTG

3

3.4.6.2 Crossbar Switch Slave Assignments
This device contains 3 slaves connected to the crossbar switch.
The slave assignment is as follows:
Slave module

Slave port number

Flash memory controller

0

SRAM controller

1

Peripheral bridge 0

2

3.4.7 Peripheral Bridge Configuration
This section summarizes how the module has been configured in the chip. For a
comprehensive description of the module itself, see the module’s dedicated chapter.

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Transfers

AIPS-Lite
peripheral bridge

Transfers

Peripherals

Crossbar switch

Chapter 3 Chip Configuration

Figure 3-10. Peripheral bridge configuration
Table 3-18. Reference links to related information
Topic

Related module

Reference

Full description

Peripheral bridge
(AIPS-Lite)

Peripheral bridge (AIPS-Lite)

System memory map

System memory map

Clocking

Clock Distribution

Crossbar switch

Crossbar switch

Crossbar switch

3.4.7.1 Number of peripheral bridges
This device contains one peripheral bridge.

3.4.7.2 Memory maps
The peripheral bridges are used to access the registers of most of the modules on this
device. See AIPS0 Memory Map for the memory slot assignment for each module.

3.4.8 DMA request multiplexer configuration
This section summarizes how the module has been configured in the chip. For a
comprehensive description of the module itself, see the module’s dedicated chapter.

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System Modules
Peripheral
bridge 0
Register
access

DMA controller

Requests
Channel
request

DMA Request
Multiplexer

Module
Module

Module

Figure 3-11. DMA request multiplexer configuration
Table 3-19. Reference links to related information
Topic

Related module

Reference

Full description

DMA request
multiplexer

DMA Mux

System memory map

System memory map

Clocking

Clock distribution

Power management

Power management

Channel request

DMA controller

DMA Controller

Requests

DMA request sources

3.4.8.1 DMA MUX Request Sources
This device includes a DMA request mux that allows up to 63 DMA request signals to be
mapped to any of the 4 DMA channels. Because of the mux there is no hard correlation
between any of the DMA request sources and a specific DMA channel. Some of the
modules support Asynchronous DMA operation as indicated by the last column in the
following DMA source assignment table.
Table 3-20. DMA request sources - MUX 0
Source
number

Source module

Source description

Async DMA
capable

0

—

Channel disabled1

1

Reserved

Not used

2

UART0

Receive

Yes

3

UART0

Transmit

Yes

4

UART1

Receive

5

UART1

Transmit

6

UART2

Receive

7

UART2

Transmit
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Chapter 3 Chip Configuration

Table 3-20. DMA request sources - MUX 0 (continued)
Source
number

Source module

Source description

Async DMA
capable

8

Reserved

—

9

Reserved

—

10

Reserved

—

11

Reserved

—

12

Reserved

—

13

Reserved

—

14

Reserved

—

15

Reserved

—

16

SPI0

Receive

17

SPI0

Transmit

18

SPI1

Receive

19

SPI1

Transmit

20

Reserved

—

21

Reserved

—

22

I2C0

—

23

I2C1

—

24

TPM0

Channel 0

Yes

25

TPM0

Channel 1

Yes

26

TPM0

Channel 2

Yes

27

TPM0

Channel 3

Yes

28

TPM0

Channel 4

Yes

29

TPM0

Channel 5

Yes

30

Reserved

—

31

Reserved

—

32

TPM1

Channel 0

Yes

33

TPM1

Channel 1

Yes

34

TPM2

Channel 0

Yes

35

TPM2

Channel 1

Yes

36

Reserved

—

37

Reserved

—

38

Reserved

—

39

Reserved

—

40

ADC0

—

41

Reserved

—

42

CMP0

—

43

Reserved

—

44

Reserved

—

45

DAC0

—

46

Reserved

—

Yes
Yes

Table continues on the next page...

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System Modules

Table 3-20. DMA request sources - MUX 0 (continued)
Source
number

Source module

Source description

Async DMA
capable

47

Reserved

—

48

Reserved

—

49

Port control module

Port A

50

Reserved

—

51

Reserved

—

52

Port control module

Port D

53

Reserved

—

54

TPM0

Overflow

Yes

55

TPM1

Overflow

Yes

56

TPM2

Overflow

Yes

57

TSI

—

Yes

58

Reserved

—

59

Reserved

—

60

DMA MUX

Always enabled

61

DMA MUX

Always enabled

62

DMA MUX

Always enabled

63

DMA MUX

Always enabled

Yes

Yes

1. Configuring a DMA channel to select source 0 or any of the reserved sources disables that DMA channel.

3.4.8.2 DMA transfers via PIT trigger
The PIT module can trigger a DMA transfer on the first two DMA channels. The
assignments are detailed at PIT/DMA Periodic Trigger Assignments .

3.4.9 DMA Controller Configuration
This section summarizes how the module has been configured in the chip. For a
comprehensive description of the module itself, see the module’s dedicated chapter.

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Chapter 3 Chip Configuration
Peripheral
bridge 0

Transfers

DMA Controller

Requests

DMA Multiplexer

Crossbar switch

Register
access

Figure 3-12. DMA Controller configuration
Table 3-21. Reference links to related information
Topic

Related module

Reference

Full description

DMA controller

DMA controller

System memory map

System memory map

Clocking

Clock distribution

Power management

Power management

Crossbar switch

Crossbar switch

Crossbar switch

Requests

DMA request sources

3.4.10 Computer Operating Properly (COP) Watchdog
Configuration
This section summarizes how the module has been configured in the chip.
Peripheral
bridge 0

Mode Controller

Register
access

WDOG

Figure 3-13. COP watchdog configuration
Table 3-22. Reference links to related information
Topic

Related module

Reference

Clocking

Clock distribution

Power management

Power management
Table continues on the next page...

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System Modules

Table 3-22. Reference links to related information (continued)
Topic

Related module

Reference

Programming model

System Integration
Module (SIM)

SIM

3.4.10.1 COP clocks
The two clock inputs for the COP are the 1 kHz clock and the bus clock.

3.4.10.2 COP watchdog operation
The COP watchdog is intended to force a system reset when the application software fails
to execute as expected. To prevent a system reset from the COP timer (when it is
enabled), application software must reset the COP counter periodically. If the application
program gets lost and fails to reset the COP counter before it times out, a system reset is
generated to force the system back to a known starting point.
After any reset, the COP watchdog is enabled. If the COP watchdog is not used in an
application, it can be disabled by clearing COPCTRL[COPT] in the SIM.
The COP counter is reset by writing 0x55 and 0xAA (in that order) to the address of the
SIM's Service COP (SRVCOP) register during the selected timeout period. Writes do not
affect the data in the SRVCOP register. As soon as the write sequence is complete, the
COP timeout period is restarted. If the program fails to perform this restart during the
timeout period, the microcontroller resets. Also, if any value other than 0x55 or 0xAA is
written to the SRVCOP register, the microcontroller immediately resets.
The SIM's COPCTRL[COPCLKS] field selects the clock source used for the COP timer.
The clock source options are either the bus clock or an internal 1 kHz clock source. With
each clock source, there are three associated timeouts controlled by COPCTRL[COPT].
The following table summarizes the control functions of the COPCLKS and COPT bits.
The COP watchdog defaults to operation from the 1 kHz clock source and the longest
timeout for that clock source (210 cycles).
Table 3-23. COP configuration options
Control Bits
COPCTRL[COPCLKS]

Clock Source

COPCTRL[COPT]

COP Window Opens

COP Overflow Count

(COPCTRL[COPW]=1)

N/A

00

N/A

N/A

COP is disabled

0

01

1 kHz

N/A

25 cycles (32 ms)

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Chapter 3 Chip Configuration

Table 3-23. COP configuration options (continued)
Control Bits

Clock Source

COP Window Opens

COP Overflow Count

COPCTRL[COPCLKS]

COPCTRL[COPT]

0

10

1 kHz

N/A

28 cycles (256 ms)

0

11

1 kHz

N/A

210 cycles (1024 ms)

1

01

Bus

6,144 cycles

213 cycles

1

10

Bus

49,152 cycles

216 cycles

1

11

Bus

196,608 cycles

218 cycles

(COPCTRL[COPW]=1)

After the bus clock source is selected, windowed COP operation is available by setting
COPCTRL[COPW] in the SIM. In this mode, writes to the SRVCOP register to clear the
COP timer must occur in the last 25% of the selected timeout period. A premature write
immediately resets the chip. When the 1 kHz clock source is selected, windowed COP
operation is not available.
The COP counter is initialized by the first writes to the SIM's COPCTRL register and
after any system reset. Subsequent writes to the SIM's COPCTRL register have no effect
on COP operation. Even if an application uses the reset default settings of the COPT,
COPCLKS, and COPW bits, the user should write to the write-once COPCTRL register
during reset initialization to lock in the settings. This approach prevents accidental
changes if the application program becomes lost.
The write to the SRVCOP register that services (clears) the COP counter should not be
placed in an interrupt service routine (ISR) because the ISR could continue to be
executed periodically even if the main application program fails.
If the bus clock source is selected, the COP counter does not increment while the
microcontroller is in debug mode or while the system is in stop (including VLPS or LLS)
mode. The COP counter resumes when the microcontroller exits debug mode or stop
mode.
If the 1 kHz clock source is selected, the COP counter is re-initialized to zero upon entry
to either debug mode or stop (including VLPS or LLS) mode. The counter begins from
zero upon exit from debug mode or stop mode.
Regardless of the clock selected, the COP is disabled when the chip enters a VLLSx
mode. Upon a reset that wakes the chip from the VLLSx mode, the COP is re-initialized
and enabled as for any reset.

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Clock Modules

3.4.10.3 Clock Gating
This family of devices includes clock gating control for each peripheral, that is, the clock
to each peripheral can explicitly be gated on or off, using clock-gate control bits in the
SIM module.

3.5 Clock Modules
3.5.1 MCG Configuration
This section summarizes how the module has been configured in the chip. For a
comprehensive description of the module itself, see the module’s dedicated chapter.
Peripheral
bridge

System integration
module (SIM)

System
oscillator

Register
access

Multipurpose Clock
Generator (MCG)

Figure 3-14. MCG configuration
Table 3-24. Reference links to related information
Topic

Related module

Reference

Full description

MCG

MCG

System memory map

System memory map

Clocking

Clock distribution

Power management
Signal multiplexing

Power management
Port control

Signal multiplexing

3.5.1.1 MCG FLL modes
On L-series devices the MCGFLLCLK frequency is limited to 48 MHz max. The DCO is
limited to the two lowest range settings (MCG_C4[DRST_DRS] must be set to either
0b00 or 0b01).

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Chapter 3 Chip Configuration

3.5.2 OSC Configuration
This section summarizes how the module has been configured in the chip. For a
comprehensive description of the module itself, see the module’s dedicated chapter.
Peripheral
bridge

Module signals

RTC

System oscillator

Signal multiplexing

MCG

Register
access

Figure 3-15. OSC configuration
Table 3-25. Reference links to related information
Topic

Related module

Full description

OSC

Reference
OSC

System memory map

System memory map

Clocking

Clock distribution

Power management

Power management

Signal multiplexing

Port control

Signal multiplexing

Full description

MCG

MCG

3.5.2.1 OSC modes of operation with MCG and RTC
The most common method of controlling the OSC block is through MCG clock source
selection MCG_C1[CLKS] and the MCG_C2 register bits to configure the oscillator
frequency range, gain-mode, and for crystal or external clock operation. The OSC_CR
also provides control for enabling the OSC and configuring internal load capacitors for
the EXTAL and XTAL pins. See the OSC and MCG chapters for more details.
The RTC_CR[OSCE] bit has overriding control over the MCG and OSC_CR enable
functions. When RTC_CR[OSCE] is set, the OSC is configured for low frequency, low
power and the RTC_CR[SCxP] bits override the OSC_CR[SCxP] bits to control the
internal capacitance configuration. See the RTC chapter for more details.

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Memories and Memory Interfaces

3.6 Memories and Memory Interfaces
3.6.1 Flash Memory Configuration
This section summarizes how the module has been configured in the chip. For a
comprehensive description of the module itself, see the module’s dedicated chapter.
Peripheral bus
controller 0

Flash memory
controller

Register
access

Transfers

Flash memory

Figure 3-16. Flash memory configuration
Table 3-26. Reference links to related information
Topic

Related module

Reference

Full description

Flash memory

Flash memory

System memory map

System memory map

Clocking

Clock Distribution

Transfers

Flash memory
controller

Flash memory controller

Register access

Peripheral bridge

Peripheral bridge

3.6.1.1 Flash Memory Sizes
The devices covered in this document contain 1 program flash block consisting of 1 KB
sectors.
The amounts of flash memory for the devices covered in this document are:
Table 3-27. KL25 flash memory size
Device

Program flash (KB)

Block 0 (P-Flash) address range

MKL25Z32VFM4

32

0x0000_0000 – 0x0000_7FFF

MKL25Z64VFM4

64

0x0000_0000 – 0x0000_FFFF

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Chapter 3 Chip Configuration

Table 3-27. KL25 flash memory size (continued)
Device

Program flash (KB)

Block 0 (P-Flash) address range

MKL25Z128VFM4

128

0x0000_0000 – 0x0001_FFFF

MKL25Z32VFT4

32

0x0000_0000 – 0x0000_7FFF

MKL25Z64VFT4

64

0x0000_0000 – 0x0000_FFFF

MKL25Z128VFT4

128

0x0000_0000 – 0x0001_FFFF

MKL25Z32VLH4

32

0x0000_0000 – 0x0000_7FFF

MKL25Z64VLH4

64

0x0000_0000 – 0x0000_FFFF

MKL25Z128VLH4

128

0x0000_0000 – 0x0001_FFFF

MKL25Z32VLK4

32

0x0000_0000 – 0x0000_7FFF

MKL25Z64VLK4

64

0x0000_0000 – 0x0000_FFFF

MKL25Z128VLK4

128

0x0000_0000 – 0x0001_FFFF

3.6.1.2 Flash Memory Map
The flash memory and the flash registers are located at different base addresses as shown
in the following figure. The base address for each is specified in System memory map.
Flash memory base address
Registers

Program flash base address

Flash configuration field
Program flash

Figure 3-17. Flash memory map

The on-chip Flash is implemented in a portion of the allocated Flash range to form a
contiguous block in the memory map beginning at address 0x0000_0000. See Flash
Memory Sizes for details of supported ranges.
Accesses to the flash memory ranges outside the amount of Flash on the device causes
the bus cycle to be terminated with an error followed by the appropriate response in the
requesting bus master. Read collision events in which flash memory is accessed while a
flash memory resource is being manipulated by a flash command also generates a bus
error response.

3.6.1.3 Flash Security
How flash security is implemented on this device is described in Chip Security.
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Memories and Memory Interfaces

3.6.1.4 Flash Modes
The flash memory chapter defines two modes of operation - NVM normal and NVM
special modes. On this device, The flash memory only operates in NVM normal mode.
All references to NVM special mode should be ignored.

3.6.1.5 Erase All Flash Contents
In addition to software, the entire flash memory may be erased external to the flash
memory via the SW-DP debug port by setting MDM-AP CONTROL[0]. MDM-AP
STATUS[0] is set to indicate the mass erase command has been accepted. MDM-AP
STATUS[0] is cleared when the mass erase completes.

3.6.1.6 FTFA_FOPT Register
The flash memory's FTFA_FOPT register allows the user to customize the operation of
the MCU at boot time. See FOPT boot options for details of its definition.

3.6.2 Flash Memory Controller Configuration
This section summarizes how the module has been configured in the chip. For a
comprehensive description of the module itself, see the module’s dedicated chapter.
See MCM_PLACR register description for details on the reset configuration of the FMC.

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Chapter 3 Chip Configuration

Transfers

Flash memory
controller

Transfers

Flash memory

Crossbar switch

MCM

Figure 3-18. Flash memory controller configuration
Table 3-28. Reference links to related information
Topic

Related module

Reference

Full description

Flash memory
controller

Flash memory controller

System memory map

System memory map

Clocking

Clock Distribution

Transfers

Flash memory

Flash memory

Transfers

Crossbar switch

Crossbar Switch

Register access

MCM

MCM

3.6.3 SRAM Configuration
This section summarizes how the module has been configured in the chip.
Transfers

SRAM upper

crossbar

Cortex-M0+
core

switch

SRAM
controller

SRAM lower
Figure 3-19. SRAM configuration
Table 3-29. Reference links to related information
Topic

Related module

Reference

Full description

SRAM

SRAM

System memory map

System memory map

Clocking

Clock Distribution

ARM Cortex-M0+ core

ARM Cortex-M0+ core

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Memories and Memory Interfaces

3.6.3.1 SRAM Sizes
This device contains SRAM which could be accessed by bus masters through the crossbar switch. The amount of SRAM for the devices covered in this document is shown in
the following table.
Table 3-30. KL25 SRAM memory size
Device

SRAM (KB)

MKL25Z32VFM4

4

MKL25Z64VFM4

8

MKL25Z128VFM4

16

MKL25Z32VFT4

4

MKL25Z64VFT4

8

MKL25Z128VFT4

16

MKL25Z32VLH4

4

MKL25Z64VLH4

8

MKL25Z128VLH4

16

MKL25Z32VLK4

4

MKL25Z64VLK4

8

MKL25Z128VLK4

16

3.6.3.2 SRAM Ranges
The on-chip SRAM is split into two ranges, 1/4 is allocated SRAM_L and 3/4 is allocated
to SRAM_U.
The on-chip RAM is implemented such that the SRAM_L and SRAM_U ranges form a
contiguous block in the memory map. As such:
• SRAM_L is anchored to 0x1FFF_FFFF and occupies the space before this ending
address.
• SRAM_U is anchored to 0x2000_0000 and occupies the space after this beginning
address.
Valid address ranges for SRAM_L and SRAM_U are then defined as:
• SRAM_L = [0x2000_0000–(SRAM_size/4)] to 0x1FFF_FFFF
• SRAM_U = 0x2000_0000 to [0x2000_0000+(SRAM_size*(3/4))-1]
This is illustrated in the following figure.
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SRAM size *(1/4)

Chapter 3 Chip Configuration

0x2000_0000 – SRAM_size/4

SRAM_L

SRAM size * (3/4)

0x1FFF_FFFF
0x2000_0000

SRAM_U

0x2000_0000 + SRAM_size(3/4) - 1

Figure 3-20. SRAM blocks memory map

For example, for a device containing 16 KB of SRAM the ranges are:
• SRAM_L: 0x1FFF_F000 – 0x1FFF_FFFF
• SRAM_U: 0x2000_0000 – 0x2000_2FFF

3.6.3.3 SRAM retention in low power modes
The SRAM is retained down to VLLS3 mode. In VLLS1 and VLLS0 no SRAM is
retained.

3.7 Analog
3.7.1 16-bit SAR ADC Configuration
This section summarizes how the module has been configured in the chip. For a
comprehensive description of the module itself, see the module’s dedicated chapter.

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Analog
Peripheral bus
controller 0

Module signals

16-bit SAR ADC

Other peripherals

Signal multiplexing

Register
access

Figure 3-21. 16-bit SAR ADC configuration
Table 3-31. Reference links to related information
Topic

Related module

Reference

Full description

16-bit SAR ADC

16-bit SAR ADC

System memory map

System memory map

Clocking

Clock distribution

Power management

Power management

Signal multiplexing

Port control

Signal multiplexing

3.7.1.1 ADC Instantiation Information
This device contains one 16 -bit successive approximation ADC with up to 16-channel.
The ADC supports both software and hardware triggers. The hardware trigger sources are
listed in the Module-to-Module section.
The number of ADC channels present on the device is determined by the pinout of the
specific device package and is shown in the following table.
Table 3-32. Number of KL25 ADC channels
Device

Number of ADC channels

MKL25Z32VFM4

7

MKL25Z64VFM4

7

MKL25Z128VFM4

7

MKL25Z32VFT4

13

MKL25Z64VFT4

13

MKL25Z128VFT4

13

MKL25Z32VLH4

14

MKL25Z64VLH4

14

MKL25Z128VLH4

14

MKL25Z32VLK4

14
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Chapter 3 Chip Configuration

Table 3-32. Number of KL25 ADC channels (continued)
Device

Number of ADC channels

MKL25Z64VLK4

14

MKL25Z128VLK4

14

3.7.1.2 DMA Support on ADC
Applications may require continuous sampling of the ADC that may have considerable
load on the CPU. The ADC supports DMA request functionality for higher performance
when the ADC is sampled at a very high rate. The ADC can trigger the DMA (via DMA
req) on conversion completion.

3.7.1.3 ADC0 Connections/Channel Assignment
NOTE
As indicated by the following sections, each ADCx_DPx input
and certain ADCx_DMx inputs may operate as single-ended
ADC channels in single-ended mode.
3.7.1.3.1

ADC0 Channel Assignment

ADC Channel
(SC1n[ADCH])

Channel

Input signal
(SC1n[DIFF]= 1)

Input signal
(SC1n[DIFF]= 0)

00000

DAD0

ADC0_DP0 and ADC0_DM0

ADC0_DP0/ADC0_SE0

00001

DAD1

ADC0_DP1 and ADC0_DM1

ADC0_DP1/ADC0_SE1

00010

DAD2

ADC0_DP2 and ADC0_DM2

ADC0_DP2/ADC0_SE2

00011

DAD3

ADC0_DP3 and ADC0_DM3

ADC0_DP3/ADC0_SE3

001001

AD4a

Reserved

ADC0_DM0/ADC0_SE4a

001011

AD5a

Reserved

ADC0_DM1/ADC0_SE5a

001101

AD6a

Reserved

ADC0_DM2/ADC0_SE6a

001111

AD7a

Reserved

ADC0_DM3/ADC0_SE7a

001001

AD4b

Reserved

ADC0_SE4b

001011

AD5b

Reserved

ADC0_SE5b

001101

AD6b

Reserved

ADC0_SE6b

001111

AD7b

Reserved

ADC0_SE7b

01000

AD8

Reserved

ADC0_SE8

01001

AD9

Reserved

ADC0_SE9

01010

AD10

Reserved

Reserved

Table continues on the next page...

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Analog

ADC Channel
(SC1n[ADCH])

Channel

Input signal
(SC1n[DIFF]= 1)

Input signal
(SC1n[DIFF]= 0)

01011

AD11

Reserved

ADC0_SE11

01100

AD12

Reserved

ADC0_SE12

01101

AD13

Reserved

ADC0_SE13

01110

AD14

Reserved

ADC0_SE14

01111

AD15

Reserved

ADC0_SE15

10000

AD16

Reserved

Reserved

10001

AD17

Reserved

Reserved

10010

AD18

Reserved

Reserved

10011

AD19

Reserved

Reserved

10100

AD20

Reserved

Reserved

10101

AD21

Reserved

Reserved

10110

AD22

Reserved

Reserved

10111

AD23

Reserved

12-bit DAC0 Output/
ADC0_SE23

11000

AD24

Reserved

Reserved

11001

AD25

Reserved

Reserved

11010

AD26

Temperature Sensor (Diff)

11011

AD27

Bandgap

(Diff)2

11100

AD28

Reserved

Reserved

11101

AD29

-VREFH (Diff)

VREFH (S.E)

11110

AD30

Reserved

VREFL

11111

AD31

Module Disabled

Module Disabled

Temperature Sensor (S.E)
Bandgap (S.E)2

1. ADCx_CFG2[MUXSEL] bit selects between ADCx_SEn channels a and b. Refer to MUXSEL description in ADC chapter
for details.
2. This is the PMC bandgap 1V reference voltage. Prior to reading from this ADC channel, ensure that you enable the
bandgap buffer by setting the PMC_REGSC[BGBE] bit. Refer to the device data sheet for the bandgap voltage (VBG)
specification.

3.7.1.4 ADC Analog Supply and Reference Connections
This device includes dedicated VDDA and VSSA pins.
This device contains separate VREFH and VREFL pins on 48-pin and higher devices.
These pins are internally connected to VDDA and VSSA respectively, on 32-pin devices.

3.7.1.5 ADC Reference Options
The ADC supports the following references:
• VREFH/VREFL - connected as the primary reference option
• VDDA - connected as the VALT reference option
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Chapter 3 Chip Configuration

3.7.2 CMP Configuration
This section summarizes how the module has been configured in the chip. For a
comprehensive description of the module itself, see the module’s dedicated chapter.
Peripheral
bridge 0

Other peripherals

CMP

Module signals

Signal multiplexing

Register
access

Figure 3-22. CMP configuration
Table 3-33. Reference links to related information
Topic

Related module

Full description

Comparator (CMP)

Reference
Comparator

System memory map

System memory map

Clocking

Clock distribution

Power management

Power management

Signal multiplexing

Port control

Signal multiplexing

3.7.2.1 CMP Instantiation Information
The device includes one high speed comparator and two 8-input multiplexors for both the
inverting and non-inverting inputs of the comparator. Each CMP input channel connects
to both muxes. Two of the channels are connected to internal sources, leaving resources
to support up to 6 input pins. See the channel assignment table for a summary of CMP
input connections for this device.
The CMP also includes one 6-bit DAC with a 64-tap resistor ladder network, which
provides a selectable voltage reference for applications where voltage reference is needed
for internal connection to the CMP.
The CMP can be optionally on in all modes except VLLS0.
The CMP has several module to module interconnects in order to facilitate ADC
triggering, TPM triggering and UART IR interfaces. For complete details on the CMP
module interconnects please refer to the Module-to-Module section.
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Analog

The CMP does not support window compare function and CMP_CR1[WE] must always
be written to 0. The sample function has limited functionality since the SAMPLE input to
the block is not connected to a valid input. Usage of sample operation is limited to a
divided version of the bus clock (CMP_CR1[SE] = 0).
Due to the pin number limitation, the CMP pass through mode is not supported by this
device, so the CMPx_MUXCR[PSTM] must be left as 0.

3.7.2.2 CMP input connections
The following table shows the fixed internal connections to the CMP.
Table 3-34. CMP input connections
CMP Inputs

CMP0

IN0

CMP0_IN0

IN1

CMP0_IN1

IN2

CMP0_IN2

IN3

CMP0_IN3

IN4

12-bit DAC0 reference/ CMP0_IN4

IN5

CMP0_IN5

IN6

Bandgap1

IN7

6-bit DAC0 reference

1. This is the PMC bandgap 1V reference voltage. Prior to using as CMP input, ensure that you enable the bandgap buffer by
setting the PMC_REGSC[BGBE] bit. Refer to the device data sheet for the bandgap voltage (VBG) specification.

3.7.2.3 CMP external references
The 6-bit DAC sub-block supports selection of two references. For this device, the
references are connected as follows:
• VREFH - Vin1 input. When using VREFH, any ADC conversion using this same
reference at the same time is negatively impacted.
• VDD - Vin2 input

3.7.2.4 CMP trigger mode
The CMP and 6-bit DAC sub-block supports trigger mode operation when the
CMP_CR1[TRIGM] is set. When trigger mode is enabled, the trigger event will initiate a
compare sequence that must first enable the CMP and DAC prior to performing a CMP
operation and capturing the output. In this device, control for this two staged sequencing
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Chapter 3 Chip Configuration

is provided from the LPTMR. The LPTMR triggering output is always enabled when the
LPTMR is enabled. The first signal is supplied to enable the CMP and DAC and is
asserted at the same time as the TCF flag is set. The delay to the second signal that
triggers the CMP to capture the result of the compare operation is dependent on the
LPTMR configuration. In Time Counter mode with prescaler enabled, the delay is 1/2
Prescaler output period. In Time Counter mode with prescaler bypassed, the delay is 1/2
Prescaler clock period.
The delay between the first signal from LPTMR and the second signal from LPTMR
must be greater than the Analog comparator initialization delay as defined in the device
datasheet.

3.7.3 12-bit DAC Configuration
This section summarizes how the module has been configured in the chip. For a
comprehensive description of the module itself, see the module’s dedicated chapter.
Peripheral bus
controller 0

Other peripherals

Module signals

12-bit DAC

Signal multiplexing

Register
access

Figure 3-23. 12-bit DAC configuration
Table 3-35. Reference links to related information
Topic

Related module

Reference

Full description

12-bit DAC

12-bit DAC

System memory map

System memory map

Clocking

Clock distribution

Power management

Power management

Signal multiplexing

Port control

Signal multiplexing

3.7.3.1 12-bit DAC Instantiation Information
This device contains one 12-bit digital-to-analog converter (DAC) with programmable
reference generator output. The DAC includes a two word FIFO for DMA support.
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Timers

3.7.3.2 12-bit DAC Output
The output of the DAC can be placed on an external pin or selected as an input to the
analog comparator or ADC.

3.7.3.3 12-bit DAC Analog Supply and Reference Connections
This device includes dedicated VDDA and VSSA pins.
This device contains separate VREFH and VREFL pins on 48-pin and higher devices.
These pins are internally connected to VDDA and VSSA respectively, on 32-pin devices.

3.7.3.4 12-bit DAC Reference
For this device VREFH and VDDA are selectable as the DAC reference. VREFH is
connected to the DACREF_1 input and VDDA is connected to the DACREF_2 input.
Use DACx_C0[DACRFS] control bit to select between these two options.
Be aware that if the DAC and ADC use the same reference simultaneously, some
degradation of ADC accuracy is to be expected due to DAC switching.

3.8 Timers
3.8.1 Timer/PWM Module Configuration
This section summarizes how the module has been configured in the chip. For a
comprehensive description of the module itself, see the module’s dedicated chapter.

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Chapter 3 Chip Configuration
Peripheral bus
controller 0

TPM

Other peripherals

Module signals

Signal multiplexing

Register
access

Figure 3-24. TPM configuration
Table 3-36. Reference links to related information
Topic

Related module

Reference

Full description

Timer/PWM Module

Timer/PWM Module

System memory map

System memory map

Clocking

Clock distribution

Power management

Power management

Signal multiplexing

Port control

Signal multiplexing

3.8.1.1 TPM Instantiation Information
This device contains three Low Power TPM modules (TPM). All TPM modules in the
device only are configured as basic TPM function, and no quadrature decoder function
and all can be functional in Stop/VLPS mode. The clock source is either external or
internal in Stop/VLPS mode.
The following table shows how these modules are configured.
Table 3-37. TPM configuration
TPM instance

Number of channels

Features/usage

TPM0

6

Basic TPM,functional in Stop/VLPS mode

TPM1

2

Basic TPM,functional in Stop/VLPS mode

TPM2

2

Basic TPM,functional in Stop/VLPS mode

There are several connections to and from the TPMs in order to facilitate customer use
cases. For complete details on the TPM module interconnects please refer to the Moduleto-Module section.

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Timers

3.8.1.2 Clock Options
The TPM blocks are clocked from a single TPM clock that can be selected from
OSCERCLK, MCGIRCLK, MCGPLLCLK/2, or MCGFLLCLK. The selected source is
controlled by SIM_SOPT2[TPMSRC] and SIM_SOPT2[PLLFLLSEL]control registers.
Each TPM also supports an external clock mode (TPM_SC[CMOD]=1x) in which the
counter increments after a synchronized (to the selected TPM clock source) rising edge
detect of an external clock input. The available external clock (either TPM_CLKIN0 or
TPM_CLKIN1) is selected by SIM_SOPT4[TPMxCLKSEL] control register. To
guarantee valid operation the selected external clock must be less than half the frequency
of the selected TPM clock source.

3.8.1.3 Trigger Options
Each TPM has a selectable trigger input source controlled by the
TPMx_CONF[TRGSEL] field to use for starting the counter and/or reloading the
counter. The options available are shown in the following table.
Table 3-38. TPM trigger options
TPMx_CONF[TRGSEL]

Selected source

0000

External trigger pin input (EXTRG_IN)

0001

CMP0 output

0010

Reserved

0011

Reserved

0100

PIT trigger 0

0101

PIT trigger 1

0110

Reserved

0111

Reserved

1000

TPM0 overflow

1001

TPM1 overflow

1010

TPM2 overflow

1011

Reserved

1100

RTC alarm

1101

RTC seconds

1110

LPTMR trigger

1111

Reserved

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Chapter 3 Chip Configuration

3.8.1.4 Global Timebase
Each TPM has a global timebase feature controlled by the TPMx_CONF[GTBEEN] bit.
TPM1 is configured as the global time when this option is enabled.

3.8.1.5 TPM Interrupts
The TPM has multiple sources of interrupt. However, these sources are OR'd together to
generate a single interrupt request to the interrupt controller. When an TPM interrupt
occurs, read the TPM status registers to determine the exact interrupt source.

3.8.2 PIT Configuration
This section summarizes how the module has been configured in the chip. For a
comprehensive description of the module itself, see the module’s dedicated chapter.
Peripheral
bridge
Register
access

Periodic interrupt
timer

Figure 3-25. PIT configuration
Table 3-39. Reference links to related information
Topic

Related module

Reference

Full description

PIT

PIT

System memory map

System memory map

Clocking

Clock Distribution

Power management

Power management

3.8.2.1 PIT/DMA Periodic Trigger Assignments
The PIT generates periodic trigger events to the DMA channel mux as shown in the table
below.

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Timers

Table 3-40. PIT channel assignments for periodic DMA triggering
PIT Channel

DMA Channel Number

PIT Channel 0

DMA Channel 0

PIT Channel 1

DMA Channel 1

3.8.2.2 PIT/ADC Triggers
PIT triggers are selected as ADCx trigger sources using the SOPT7[ADCxTRGSEL] bits
in the SIM module. For more details, refer to SIM chapter.

3.8.2.3 PIT/TPM Triggers
PIT triggers are selected as TPMx trigger sources using the TPMx_CONF[TRGSEL] bits
in the TPM module. For more details, refer to TPM chapter.

3.8.2.4 PIT/DAC Triggers
PIT Channel 0 is configured as the DAC hardware trigger source. For more details, refer
to DAC chapter.

3.8.3 Low-power timer configuration
Peripheral
bridge

Low-power timer

Module signals

Signal multiplexing

Register
access

Figure 3-26. LPT configuration
Table 3-41. Reference links to related information
Topic

Related module

Reference

Full description

Low-power timer

Low-power timer

Table continues on the next page...

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Chapter 3 Chip Configuration

Table 3-41. Reference links to related information (continued)
Topic

Related module

Reference

System memory map

System memory map

Clocking

Clock Distribution

Power management

Power management

Signal Multiplexing

Port control

Signal Multiplexing

3.8.3.1 LPTMR Instantiation Information
The low-power timer (LPTMR) allows operation during all power modes. The LPTMR
can operate as a real-time interrupt or pulse accumulator. It includes a 15-bit prescaler
(real-time interrupt mode) or glitch filter (pulse accumulator mode).
The LPTMR can be clocked from the internal reference clock, the internal 1 kHz LPO,
OSCERCLK, or an external 32.768 kHz crystal. In VLLS0 mode, the clocking option is
limited to an external pin with the OSC configured for bypass (external clock) operation.
An interrupt is generated (and the counter may reset) when the counter equals the value
in the 16-bit compare register.

3.8.3.2 LPTMR pulse counter input options
The LPTMR_CSR[TPS] bitfield configures the input source used in pulse counter mode.
The following table shows the chip-specific input assignments for this bitfield.
LPTMR_CSR[TPS]

Pulse counter input number

Chip input

00

0

CMP0 output

01

1

LPTMR_ALT1 pin

10

2

LPTMR_ALT2 pin

11

3

LPTMR_ALT3 pin

3.8.3.3 LPTMR prescaler/glitch filter clocking options
The prescaler and glitch filter of the LPTMR module can be clocked from one of four
sources determined by the LPTMR0_PSR[PCS] bitfield. The following table shows the
chip-specific clock assignments for this bitfield.

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Timers

NOTE
The chosen clock must remain enabled if the LPTMR is to
continue operating in all required low-power modes.
LPTMR0_PSR[PCS]

Prescaler/glitch filter clock
number

Chip clock

00

0

MCGIRCLK — internal reference clock
(not available in LLS and VLLS modes)

01

1

LPO — 1 kHz clock (not available in
VLLS0 mode)

10

2

ERCLK32K (not available in VLLS0
mode when using 32 kHz oscillator)

11

3

OSCERCLK — external reference clock
(not available in VLLS0 mode)

See Clock Distribution for more details on these clocks.

3.8.4 RTC configuration
This section summarizes how the module has been configured in the chip. For a
comprehensive description of the module itself, see the module’s dedicated chapter.
Peripheral
bridge

Module signals

Real-time clock

Signal multiplexing

Register
access

Figure 3-27. RTC configuration
Table 3-42. Reference links to related information
Topic

Related module

Reference

Full description

RTC

RTC

System memory map

System memory map

Clocking

Clock Distribution

Power management

Power management

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Chapter 3 Chip Configuration

3.8.4.1 RTC Instantiation Information
RTC prescaler is clocked by ERCLK32K.
RTC is reset on POR Only.
RTC_CR[OSCE] can override the configuration of the System OSC, configuring the
OSC for 32kHz crystal operation in all power modes (except VLLS0) and through any
System Reset. When OSCE is enabled, the RTC also overrides the capacitor
configurations.

3.8.4.2 RTC_CLKOUT options
RTC_CLKOUT pin can be driven either with the RTC 1 Hz output or with the
OSCERCLK on-chip clock source. Control for this option is through
SIM_SOPT2[RTCCLKOUTSEL] bit.
When RTCCLKOUTSEL=0, the RTC 1 Hz clock is output is selected on the
RTC_CLKOUT pin. When RTCCLKOUTSEL=1, OSCERCLK clock is output on the
RTC_CLKOUT pin.

3.9 Communication interfaces
3.9.1 Universal Serial Bus (USB) FS Subsystem
The USB FS subsystem includes these components:
• Dual-role USB OTG-capable (On-The-Go) controller that supports a full-speed (FS)
device or FS/LS host. The module complies with the USB 2.0 specification.
• USB transceiver that includes internal 15 kΩ pulldowns on the D+ and D- lines for
host mode functionality.
• A 3.3 V regulator.
• VBUS detect signal: To detect a valid VBUS in device mode, use a GPIO signal that
can wake the chip in all power modes.

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Communication interfaces

USB controller

USB voltage
regulator

VREGIN

FS/LS
transceiver

VOUT33

D+

D-

Figure 3-28. USB Subsystem Overview

3.9.1.1 USB Wakeup
When the USB detects that there is no activity on the USB bus for more than 3 ms, the
INT_STAT[SLEEP] bit is set. This bit can cause an interrupt and software decides the
appropriate action.
Waking from a low power mode (except in LLS/VLLS mode where USB is not powered)
occurs through an asynchronous interrupt triggered by activity on the USB bus. Setting
the USBTRC0[USBRESMEN] bit enables this function.

3.9.1.2 USB Power Distribution
This chip includes an internal 5 V to 3.3 V USB regulator that powers the USB
transceiver or the MCU (depending on the application).
3.9.1.2.1

AA/AAA cells power supply

The chip can be powered by two AA/AAA cells. In this case, the MCU is powered
through VDD which is within the 1.8 to 3.0 V range. After USB cable insertion is
detected, the USB regulator is enabled to power the USB transceiver.

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Chapter 3 Chip Configuration

2 AA Cells

VDD

To PMC and Pads

VOUT33
Cstab
TYPE A
VBUS

Chip

VREGIN

D+

USB0_DP

D-

USB0_DM

USB
Regulator
USB
XCVR

USB
Controller

Figure 3-29. USB regulator AA cell usecase

3.9.1.2.2

Li-Ion battery power supply

The chip can also be powered by a single Li-ion battery. In this case, VOUT33 is
connected to VDD. The USB regulator must be enabled by default to power the MCU.
When connected to a USB host, the input source of this regulator is switched to the USB
bus supply from the Li-ion battery. To charge the battery, the MCU can configure the
battery charger.

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Communication interfaces

VDD

To PMC and Pads

VOUT33
Cstab
Chip

TYPE A
VBUS Charger Si2301

VREGIN

USB
Regulator

D+

USB
XCVR

USB0_DP

DVSS

Li-Ion

USB
Controller

USB0_DM

Figure 3-30. USB regulator Li-ion usecase

3.9.1.2.3

USB bus power supply

The chip can also be powered by the USB bus directly. In this case, VOUT33 is
connected to VDD. The USB regulator must be enabled by default to power the MCU,
then to power USB transceiver or external sensor.
VDD

Cstab

TYPE A
VBUS

To PMC and Pads

VOUT33

Chip
VREGIN

D+

USB0_DP

D-

USB0_DM

USB
Regulator
XCVR

USB

USB
Controller

Figure 3-31. USB regulator bus supply

3.9.1.3 USB power management
The regulator should be put into STANDBY mode whenever the chip is in Stop mode.
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Chapter 3 Chip Configuration

3.9.1.4 USB controller configuration
This section summarizes how the module has been configured in the chip. For a
comprehensive description of the module itself, see the module’s dedicated chapter.
Peripheral
bridge 0

Transfers

USB controller

Module signals

Signal multiplexing

Crossbar switch

Register
access

Figure 3-32. USB controller configuration
Table 3-43. Reference links to related information
Topic

Related module

Reference

Full description

USB controller

USB controller

System memory map

System memory map

Clocking

Clock Distribution

Transfers

Crossbar switch

Crossbar switch

Signal Multiplexing

Port control

Signal Multiplexing

NOTE
When USB is not used in the application, it is recommended
that the USB regulator VREGIN and VOUT33 pins remain
floating.

3.9.1.5 USB Voltage Regulator Configuration
This section summarizes how the module has been configured in the chip. For a
comprehensive description of the module itself, see the module’s dedicated chapter.

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USB Voltage
Regulator

Module signals

Signal multiplexing

USB OTG

Communication interfaces

Figure 3-33. USB Voltage Regulator configuration
Table 3-44. Reference links to related information
Topic

Related module

Reference

Full description

USB Voltage Regulator

USB Voltage Regulator

System memory map

System memory map

Clocking

Clock Distribution

Signal Multiplexing

USB controller

USB controller

Port control

Signal Multiplexing

NOTE
When USB is not used in the application, it is recommended
that the USB regulator VREGIN and VOUT33 pins remain
floating.

3.9.2 SPI configuration
This section summarizes how the module has been configured in the chip. For a
comprehensive description of the module itself, see the module’s dedicated chapter.
Peripheral
bridge

SPI

Module signals

Signal multiplexing

Register
access

Figure 3-34. SPI configuration
Table 3-45. Reference links to related information
Topic

Related module

Reference

Full description

SPI

SPI

System memory map

System memory map

Clocking

Clock Distribution
Table continues on the next page...

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Chapter 3 Chip Configuration

Table 3-45. Reference links to related information (continued)
Topic

Related module

Reference

Signal Multiplexing

Port control

Signal Multiplexing

3.9.2.1 SPI Instantiation Information
This device contains two SPI module that supports 8-bit data length.
SPI0 is clocked on the bus clock. SPI1 is clocked from the system clock. SPI1 is
therefore disabled in "Partial Stop Mode".
The SPI supports DMA request and can operate in VLPS mode. When the SPI is
operating in VLPS mode, it will operate as a slave.
SPI can wakeup MCU from VLPS mode upon reception of SPI data in slave mode.

3.9.3 I2C Configuration
This section summarizes how the module has been configured in the chip. For a
comprehensive description of the module itself, see the module’s dedicated chapter.
Peripheral
bridge

I2 C

Module signals

Signal multiplexing

Register
access

Figure 3-35. I2C configuration
Table 3-46. Reference links to related information
Topic

Related module

Reference

Full description

I2C

I2C

System memory map

System memory map

Clocking

Clock Distribution

Power management

Power management

Signal Multiplexing

Port control

Signal Multiplexing

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Communication interfaces

3.9.3.1 IIC Instantiation Information
This device has two IIC module.
When the package pins associated with IIC have their mux select configured for IIC
operation, the pins (SCL and SDA) are driven in a pseudo open drain configuration.
The digital glitch filter implemented in the IICx module, controlled by the
I2Cx_FLT[FLT] registers, is clocked from the bus clock and thus has filter granularity in
bus clock cycle counts.

3.9.4 UART Configuration
This section summarizes how the module has been configured in the chip. For a
comprehensive description of the module itself, see the module’s dedicated chapter.
Peripheral
bridge

Module signals

UART

Signal multiplexing

Register
access

Figure 3-36. UART configuration
Table 3-47. Reference links to related information
Topic

Related module

Reference

Full description

UART1 and UART2

UART

Full description

UART0

UART

System memory map

System memory map

Clocking

Clock Distribution

Power management

Power management

Signal Multiplexing

Port control

Signal Multiplexing

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Chapter 3 Chip Configuration

3.9.4.1 UART0 overview
The UART0 module supports basic UART with DMA interface function, x4 to x32
oversampling of baud-rate.
This module supports LIN slave operation.
The module can remain functional in VLPS mode provided the clock it is using remains
enabled.
ISO7816 protocol is intended to be handled in software for this product. To support smart
card reading, TxD pin can be configured as pseudo open drain for 1-wire half-duplex like
ISO7816 communication via the SIM_SOPT5[UART0ODE] bit.

3.9.4.2 UART1 and UART2 Overview
This device contains two basic universal asynchronous receiver/transmitter (UART)
modules with DMA function support. Generally, these modules are used in RS-232,
RS-485, and other communications. This module supports LIN Slave operation.

3.10 Human-machine interfaces (HMI)
3.10.1 GPIO Configuration
Peripheral
bridge

Register access

Module signals

GPIO controller

Signal multiplexing

ARM Cortex -M0+
Core

Register
access

Figure 3-37. GPIO configuration
Table 3-48. Reference links to related information
Topic

Related module

Reference

Full description

GPIO

GPIO

System memory map

System memory map

Clocking

Clock Distribution
Table continues on the next page...

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Human-machine interfaces (HMI)

Table 3-48. Reference links to related information (continued)
Topic

Related module

Reference

Power management

Power management

Crossbar switch

Crossbar switch

Crossbar switch

Signal Multiplexing

Port control

Signal Multiplexing

3.10.1.1 GPIO Instantiation Information
The device includes four pins, PTB0, PTB1, PTD6, and PTD7, with high current drive
capability. These pins can be used to drive LED or power MOSFET directly. The high
drive capability applies to all functions which are multiplexed on these pins (UART,
TPM, SPI...etc)
3.10.1.1.1

Pull Devices and Directions

The pull devices are enabled out of POR only on RESET_B, NMI_b and respective SWD
signals. Other pins can be enabled by writing to PORTx_PCRn[PE] field.
All the pins are hard wired to be pullup except for SWD_CLK. The state will be reflected
in the PORTx_PCRn[PS] field.

3.10.1.2 Port Control and Interrupt Summary
The following table provides more information regarding the Port Control and Interrupt
configurations .
Table 3-49. Ports Summary
Feature

Port A

Port B

Port C

Port D

Port E

Pull Select control No

No

No

No

No

Pull Select at reset PTA0=Pull down,
Others=Pull up

Pull up

Pull up

Pull up

Pull up

Pull Enable control Yes

Yes

Yes

Yes

Yes

Disabled

Disabled

Disabled

No

No

No

Pull Enable at reset PTA0/PTA3/PTA4/ Disabled
RESET_b=Enabled
; Others=Disabled
Slew Rate Enable No
control

No

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Chapter 3 Chip Configuration

Table 3-49. Ports Summary (continued)
Feature

Port A

Slew Rate Enable PTA3/PTA14/
at reset
PTA15/PTA16/
PTA17=Disabled;
Others=Enabled

Port B

Port C

PTB10/PTB11/
PTB16/PTB17 =
Disabled;
Others=Enabled

PTC3/PTC4/PTC5/ PTD4/PTD5/PTD6/ PTE16/PTE17/
PTC6/
PTD7=Disabled;
PTE18/
PTC7=Disabled;
Others=Enabled
PTE19=Disabled;
Others=Enabled
Others=Enabled

No

No

No

No

Disabled

Disabled

Disabled

Passive Filter
Enable control

PTA4 and
RESET_b only

Passive Filter
Enable at reset

RESET_b=Enabled Disabled
; Others=Disabled

Port D

Port E

Open Drain Enable No
control1

No

No

No

No

Open Drain Enable Disabled
at reset

Disabled

Disabled

Disabled

Disabled

Drive Strength
Enable control

No

PTB0/PTB1 only

No

PTD6/PTD7 only

No

Drive Strength
Enable at reset

Disabled

Disabled

Disabled

Disabled

Disabled

Pin Mux control

Yes

Yes

Yes

Yes

Yes

Pin Mux at reset

PTA0/PTA3/
PTA4=ALT7;
Others=ALT0

ALT0

ALT0

ALT0

ALT0

No

No

No

No

No

Interrupt and DMA Yes
Request

Lock Bit

No

No

Yes

No

Digital Glitch Filter No

No

No

No

No

1. UART signals can be configured for open-drain using SIM_SOPT5 register. IIC signals are automatically enabled for open
drain when selected.

3.10.1.3 GPIO accessibility in the memory map
The GPIO is multi-ported and can be accessed directly by the core with zero wait states at
base address 0xF800_0000. It can also be accessed by the core and DMA masters
through the cross bar/AIPS interface at 0x400F_F000 and at an aliased slot (15) at
address 0x4000_F000. All BME operations to the GPIO space can be accomplished
referencing the aliased slot (15) at address 0x4000_F000. Only some of the BME
operations can be accomplished referencing GPIO at address 0x400F_F000.

3.10.2 TSI Configuration
This section summarizes how the module has been configured in the chip. For a
comprehensive description of the module itself, see the module’s dedicated chapter.

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Human-machine interfaces (HMI)
Peripheral
bridge

Touch sense input
module

Signal multiplexing

Register
access

Module signals

Figure 3-38. TSI configuration
Table 3-50. Reference links to related information
Topic

Related module

Reference

Full description

TSI

TSI

System memory map

System memory map

Clocking

Clock Distribution

Power management

Power management

Signal Multiplexing

Port control

Signal Multiplexing

3.10.2.1 TSI Instantiation Information
This device includes one TSI module containing the channels as shown in the following
table. In Stop, VLPS, LLS and VLLSx modes any one channel can be enabled to be the
wakeup source.
TSI hardware trigger is from the LPTMR. For complete details on the LPTMR module
interconnects refer to the Module-to-Module section.
The number of TSI channels present on the device is determined by the pinout of the
specific device package and is shown in the following table.
Table 3-51. Number of KL25 TSI channels
Device

TSI channels

MKL25Z32VFM4

9

MKL25Z64VFM4

9

MKL25Z128VFM4

9

MKL25Z32VFT4

14

MKL25Z64VFT4

14

MKL25Z128VFT4

14

MKL25Z32VLH4

16

MKL25Z64VLH4

16
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Chapter 3 Chip Configuration

Table 3-51. Number of KL25 TSI channels (continued)
Device

TSI channels

MKL25Z128VLH4

16

MKL25Z32VLK4

16

MKL25Z64VLK4

16

MKL25Z128VLK4

16

3.10.2.2 TSI Interrupts
The TSI has multiple sources of interrupt requests. However, these sources are OR'd
together to generate a single interrupt request. When a TSI interrupt occurs, read the TSI
status register to determine the exact interrupt source.

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Human-machine interfaces (HMI)

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Chapter 4
Memory Map
4.1 Introduction
This device contains various memories and memory-mapped peripherals which are
located in a 4 GB memory space. This chapter describes the memory and peripheral
locations within that memory space.

4.2 System memory map
The following table shows the high-level device memory map.
Table 4-1. System memory map
System 32-bit Address Range
0x0000_0000–0x07FF_FFFF1

Destination Slave
Program flash and read-only data

Access
All masters

(Includes exception vectors in first 196 bytes)
0x0800_0000–0x1FFF_EFFF

Reserved

—

0x1FFF_F000-0x1FFF_FFFF2

SRAM_L: Lower SRAM

All masters

0x2000_0000-0x2000_2FFF2

SRAM_U: Upper SRAM

All masters

0x2000_3000–0x3FFF_FFFF

Reserved

–

0x4000_0000–0x4007_FFFF

AIPS Peripherals

Cortex-M0+ core &
DMA

0x4008_0000–0x400F_EFFF

Reserved

–

0x400F_F000–0x400F_FFFF

General purpose input/output (GPIO)

Cortex-M0+ core &
DMA

0x4010_0000–0x43FF_FFFF

Reserved

–

0x4400_0000–0x5FFF_FFFF

Bit Manipulation Engine (BME) access to AIPS Peripherals for Cortex-M0+ core
slots 0-1273

0x6000_0000–0xDFFF_FFFF

Reserved

–

0xE000_0000–0xE00F_FFFF

Private Peripherals

Cortex-M0+ core

0xE010_0000–0xEFFF_FFFF

Reserved

–

0xF000_0000–0xF000_0FFF

Micro Trace Buffer (MTB) registers

Cortex-M0+ core

Table continues on the next page...

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Flash Memory Map

Table 4-1. System memory map (continued)
System 32-bit Address Range

Destination Slave

Access

0xF000_1000–0xF000_1FFF

MTB Data Watchpoint and Trace (MTBDWT) registers

Cortex-M0+ core

0xF000_2000–0xF000_2FFF

ROM table

Cortex-M0+ core

0xF000_3000–0xF000_3FFF

Miscellaneous Control Module (MCM)

Cortex-M0+ core

0xF000_4000–0xF7FF_FFFF

Reserved

–

0xF800_0000–0xFFFF_FFFF

IOPORT: GPIO (single cycle)

Cortex-M0+ core

1. The program flash always begins at 0x0000_0000 but the end of implemented flash varies depending on the amount of
flash implemented for a particular device. See Flash Memory Sizes for details.
2. This range varies depending on SRAM sizes. See SRAM Ranges for details.
3. Includes BME operations to GPIO at slot 15 (based at 0x4000_F000).

4.3 Flash Memory Map
The flash memory and the flash registers are located at different base addresses as shown
in the following figure. The base address for each is specified in System memory map.
Flash memory base address
Registers

Program flash base address

Flash configuration field
Program flash

Figure 4-1. Flash memory map

The on-chip Flash is implemented in a portion of the allocated Flash range to form a
contiguous block in the memory map beginning at address 0x0000_0000. See Flash
Memory Sizes for details of supported ranges.
Accesses to the flash memory ranges outside the amount of Flash on the device causes
the bus cycle to be terminated with an error followed by the appropriate response in the
requesting bus master. Read collision events in which flash memory is accessed while a
flash memory resource is being manipulated by a flash command also generates a bus
error response.

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Chapter 4 Memory Map

4.3.1 Alternate Non-Volatile IRC User Trim Description
The following non-volatile locations (4 bytes) are reserved for custom IRC user trim
supported by some development tools. An alternate IRC trim to the factory loaded trim
can be stored at this location. To override the factory trim, user software must load new
values into the MCG trim registers.
Non-Volatile Byte Address

Alternate IRC Trim Value

0x0000_03FC

Reserved

0x0000_03FD

Reserved

0x0000_03FE (bit 0)

SCFTRIM

0x0000_03FE (bit 4:1)

FCTRIM

0x0000_03FF

SCTRIM

4.4 SRAM memory map
The on-chip RAM is split between SRAM_L and SRAM_U. The RAM is also
implemented such that the SRAM_L and SRAM_U ranges form a contiguous block in
the memory map. See SRAM Ranges for details.
Accesses to the SRAM_L and SRAM_U memory ranges outside the amount of RAM on
the device causes the bus cycle to be terminated with an error followed by the appropriate
response in the requesting bus master.

4.5 Bit Manipulation Engine
The Bit Manipulation Engine (BME) provides hardware support for atomic read-modifywrite memory operations to the peripheral address space. By combining the basic load
and store instruction support in the Cortex-M instruction set architecture with the concept
of decorated storage provided by the BME, the resulting implementation provides a
robust and efficient read-modify-write capability to this class of ultra low-end
microcontrollers. See the Bit Manipulation Engine Block Guide (BME) for a detailed
description of BME functionality.

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Peripheral bridge (AIPS-Lite) memory map

4.6 Peripheral bridge (AIPS-Lite) memory map
The peripheral memory map is accessible via one slave port on the crossbar in the
0x4000_0000–0x400F_FFFF region. The device implements one peripheral bridge that
defines a 1024 KB address space.
The three regions associated with this space are:
• A 128 KB region, partitioned as 32 spaces, each 4 KB in size and reserved for onplatform peripheral devices. The AIPS controller generates unique module enables
for all 32 spaces.
• A 384 KB region, partitioned as 96 spaces, each 4 KB in size and reserved for offplatform modules. The AIPS controller generates unique module enables for all 96
spaces.
• The last slot is a 4 KB region beginning at 0x400F_F000 for accessing the GPIO
module. The GPIO slot (slot 128) is an alias of slot 15. This block is also directly
interfaced to the core and provides direct access without incurring wait states
associated with accesses via the AIPS controller.
Modules that are disabled via their clock gate control bits in the SIM registers disable the
associated AIPS slots. Access to any address within an unimplemented or disabled
peripheral bridge slot results in a transfer error termination.
For programming model accesses via the peripheral bridges, there is generally only a
small range within the 4 KB slots that is implemented. Accessing an address that is not
implemented in the peripheral results in a transfer error termination.

4.6.1 Read-after-write sequence and required serialization of
memory operations
In some situations, a write to a peripheral must be completed fully before a subsequent
action can occur. Examples of such situations include:
• Exiting an interrupt service routine (ISR)
• Changing a mode
• Configuring a function
In these situations, application software must perform a read-after-write sequence to
guarantee the required serialization of the memory operations:
1. Write the peripheral register.
2. Read the written peripheral register to verify the write.
3. Continue with subsequent operations.
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Chapter 4 Memory Map

4.6.2 Peripheral Bridge (AIPS-Lite) Memory Map
Table 4-2. Peripheral bridge 0 slot assignments
System 32-bit base address

Slot
number

Module

0x4000_0000

0

—

0x4000_1000

1

—

0x4000_2000

2

—

0x4000_3000

3

—

0x4000_4000

4

—

0x4000_5000

5

—

0x4000_6000

6

—

0x4000_7000

7

—

0x4000_8000

8

DMA controller

0x4000_9000

9

—

0x4000_A000

10

—

0x4000_B000

11

—

0x4000_C000

12

—

0x4000_D000

13

—

0x4000_E000

14

—

0x4000_F000

15

GPIO controller (aliased to 0x400F_F000)

0x4001_0000

16

—

0x4001_1000

17

—

0x4001_2000

18

—

0x4001_3000

19

—

0x4001_4000

20

—

0x4001_5000

21

—

0x4001_6000

22

—

0x4001_7000

23

—

0x4001_8000

24

—

0x4001_9000

25

—

0x4001_A000

26

—

0x4001_B000

27

—

0x4001_C000

28

—

0x4001_D000

29

—

0x4001_E000

30

—

0x4001_F000

31

—

0x4002_0000

32

Flash memory

0x4002_1000

33

DMA channel mutiplexer 0

0x4002_2000

34

—

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Peripheral bridge (AIPS-Lite) memory map

Table 4-2. Peripheral bridge 0 slot assignments (continued)
System 32-bit base address

Slot
number

Module

0x4002_3000

35

—

0x4002_4000

36

—

0x4002_5000

37

—

0x4002_6000

38

—

0x4002_7000

39

—

0x4002_8000

40

—

0x4002_9000

41

—

0x4002_A000

42

—

0x4002_B000

43

—

0x4002_C000

44

—

0x4002_D000

45

—

0x4002_E000

46

—

0x4002_F000

47

—

0x4003_0000

48

—

0x4003_1000

49

—

0x4003_2000

50

—

0x4003_3000

51

—

0x4003_4000

52

—

0x4003_5000

53

—

0x4003_6000

54

—

0x4003_7000

55

Periodic interrupt timers (PIT)

0x4003_8000

56

Timer'/PWM (TPM) 0

0x4003_9000

57

Timer'/PWM (TPM) 1

0x4003_A000

58

Timer'/PWM (TPM) 2

0x4003_B000

59

Analog-to-digital converter (ADC) 0

0x4003_C000

60

—

0x4003_D000

61

Real-time clock (RTC)

0x4003_E000

62

—

0x4003_F000

63

DAC0

0x4004_0000

64

Low-power timer (LPTMR)

0x4004_1000

65

—

0x4004_2000

66

—

0x4004_3000

67

—

0x4004_4000

68

—

0x4004_5000

69

Touch sense interface (TSI)

0x4004_6000

70

—

0x4004_7000

71

SIM low-power logic

0x4004_8000

72

System integration module (SIM)

0x4004_9000

73

Port A multiplexing control

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Chapter 4 Memory Map

Table 4-2. Peripheral bridge 0 slot assignments (continued)
System 32-bit base address

Slot
number

Module

0x4004_A000

74

Port B multiplexing control

0x4004_B000

75

Port C multiplexing control

0x4004_C000

76

Port D multiplexing control

0x4004_D000

77

Port E multiplexing control

0x4004_E000

78

—

0x4004_F000

79

—

0x4005_0000

80

—

0x4005_1000

81

—

0x4005_2000

82

—

0x4005_3000

83

—

0x4005_4000

84

—

0x4005_5000

85

—

0x4005_6000

86

—

0x4005_7000

87

—

0x4005_8000

88

—

0x4005_9000

89

—

0x4005_A000

90

—

0x4005_B000

91

—

0x4005_C000

92

—

0x4005_D000

93

—

0x4005_E000

94

—

0x4005_F000

95

—

0x4006_0000

96

—

0x4006_1000

97

—

0x4006_2000

98

—

0x4006_3000

99

—

0x4006_4000

100

Multi-purpose Clock Generator (MCG)

0x4006_5000

101

System oscillator (OSC)

0x4006_6000

102

I2C 0

0x4006_7000

103

I2C 1

0x4006_8000

104

—

0x4006_9000

105

—

0x4006_A000

106

UART 0

0x4006_B000

107

UART 1

0x4006_C000

108

UART 2

0x4006_D000

109

—

0x4006_E000

110

—

0x4006_F000

111

—

0x4007_0000

112

—

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Private Peripheral Bus (PPB) memory map

Table 4-2. Peripheral bridge 0 slot assignments (continued)
System 32-bit base address

Slot
number

Module

0x4007_1000

113

—

0x4007_2000

114

USB OTG FS/LS

0x4007_3000

115

Analog comparator (CMP) / 6-bit digital-to-analog converter (DAC)

0x4007_4000

116

—

0x4007_5000

117

—

0x4007_6000

118

SPI 0

0x4007_7000

119

SPI 1

0x4007_8000

120

—

0x4007_9000

121

—

0x4007_A000

122

—

0x4007_B000

123

—

0x4007_C000

124

Low-leakage wakeup unit (LLWU)

0x4007_D000

125

Power management controller (PMC)

0x4007_E000

126

System Mode controller (SMC)

0x4007_F000

127

Reset Control Module (RCM)

0x400F_F000

128

GPIO controller

4.6.3 Modules Restricted Access in User Mode
In user mode, for MCG, RCM, SIM (slot 71 and 72), SMC, LLWU, and PMC, reads are
allowed, but writes are blocked and generate bus error.

4.7 Private Peripheral Bus (PPB) memory map
The PPB is part of the defined ARM bus architecture and provides access to select
processor-local modules. These resources are only accessible from the core; other system
masters do not have access to them.
Table 4-3. PPB memory map
System 32-bit Address Range
0xE000_0000–0xE000_DFFF

Resource

Additional Range Detail

Resource

Reserved
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Chapter 4 Memory Map

Table 4-3. PPB memory map (continued)
System 32-bit Address Range
0xE000_E000–0xE000_EFFF

Resource
System Control Space
(SCS)

0xE000_F000–0xE00F_EFFF

Reserved

0xE00F_F000–0xE00F_FFFF

Core ROM Space (CRS)

Additional Range Detail

Resource

0xE000_E000–0xE000_E00F

Reserved

0xE000_E010–0xE000_E0FF

SysTick

0xE000_E100–0xE000_ECFF

NVIC

0xE000_ED00–0xE000_ED8F

System Control Block

0xE000_ED90–0xE000_EDEF

Reserved

0xE000_EDF0–0xE000_EEFF

Debug

0xE000_EF00–0xE000_EFFF

Reserved

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Private Peripheral Bus (PPB) memory map

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Chapter 5
Clock Distribution
5.1 Introduction
This chapter presents the clock architecture for the device, the overview of the clocks and
includes a terminology section.
The Cortex M0+ resides within a synchronous core platform, where the processor and
bus masters, Flash and peripherals clocks can be configured independently. The clock
distribution figure shows how clocks from the MCG and XOSC modules are distributed
to the microcontroller’s other function units. Some modules in the microcontroller have
selectable clock input.

5.2 Programming model
The selection and multiplexing of system clock sources is controlled and programmed via
the MCG module. The setting of clock dividers and module clock gating for the system
are programmed via the SIM module. Reference those sections for detailed register and
bit descriptions.

5.3 High-Level device clocking diagram
The following system oscillator, MCG, and SIM module registers control the
multiplexers, dividers, and clock gates shown in the below figure:
OSC

MCG

SIM

Multiplexers

MCG_Cx

MCG_Cx

SIM_SOPT1, SIM_SOPT2

Dividers

—

MCG_Cx

SIM_CLKDIVx

Clock gates

OSC_CR

MCG_C1

SIM_SCGCx

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Clock definitions

SIM

MCG
4 MHz IRC

FCRDIV

MCGIRCLK

CG

32 kHz IRC

Clock options for
some peripherals
(see note)

OUTDIV1

CG

Core clock,
platform clock,
and system clock

OUTDIV4

CG

Bus clock/
Flash clock

FLL

MCGOUTCLK

MCGFLLCLK

FRDIV

MCGPLLCLK

MCGPLLCLK/
MCGFLLCLK

÷2

System oscillator
EXTAL0

OSCCLK
XTAL_CLK

XTAL0

OSC
logic

OSCERCLK

CG

ERCLK32K

OSC32KCLK

RTC_CLKIN

Clock options for some
peripherals (see note)

PLL

PMC
PMC logic
Counter logic

LPO

RTC_CLKOUT

1Hz

RTC

CG — Clock gate
Note: See subsequent sections for details on where these clocks are used.

Figure 5-1. Clocking diagram

5.4 Clock definitions
The following table describes the clocks in the previous block diagram.
Clock name

Description

Core clock

MCGOUTCLK divided by OUTDIV1, clocks the ARM CortexM0+ core

Platform clock

MCGOUTCLK divided by OUTDIV1, clocks the crossbar
switch and NVIC

System clock

MCGOUTCLK divided by OUTDIV1, clocks the bus masters
directly

Bus clock

System clock divided by OUTDIV4, clocks the bus slaves and
peripherals.
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Chapter 5 Clock Distribution

Clock name

Description

Flash clock

Flash memory clock. On this device it is the same as Bus
clock.

MCGIRCLK

MCG output of the slow or fast internal reference clock

MCGOUTCLK

MCG output of either IRC, MCGFLLCLK, MCGPLLCLK, or
MCG's external reference clock that sources the core,
system, bus, and flash clock.

MCGFLLCLK

MCG output of the FLL. MCGFLLCLK or MCGPLLCLK may
clock some modules. In addition, this clock is used for
USBFS, UART0 and TPM modules.

MCGPLLCLK

MCG output of the PLL. MCGFLLCLK or MCGPLLCLK may
clock some modules. In addition, this clock is used for
USBFS, UART0 and TPM modules.

OSCCLK

System oscillator output of the internal oscillator or sourced
directly from EXTAL. Used as MCG external reference clock.

OSCERCLK

System oscillator output sourced from OSCCLK that may
clock some on-chip modules

OSC32KCLK

System oscillator 32kHz output

ERCLK32K

Clock source for some modules that is chosen as
OSC32KCLK or RTC_CLKIN

LPO

PMC 1kHz output

5.4.1 Device clock summary
The following table provides more information regarding the on-chip clocks.
Table 5-1. Clock Summary
Clock name

Run mode

VLPR mode

Clock source

Clock is disabled
when…

clock frequency

clock frequency

MCGOUTCLK

Up to 100 MHz

Up to 4 MHz

MCG

In all stop modes
except for partial stop
modes and during PLL
locking when
MCGOUTCLK derived
from PLL.

MCGFLLCLK

Up to 48 MHz

N/A

MCG

MCG clock controls do
not enable and in all
stop modes

MCGPLLCLK

Up to 100 MHz

N/A

MCG

MCG clock controls do
not enable,
in Stop mode but
PLLSTEN=0,
or in VLPS, LLS and
VLLSx modes

Core clock

Up to 48 MHz

Up to 4 MHz

MCGOUTCLK clock
divider

In all wait and stop
modes

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Clock definitions

Table 5-1. Clock Summary (continued)
Clock name

Run mode

VLPR mode

Clock source

Clock is disabled
when…

clock frequency

clock frequency

Platform clock

Up to 48 MHz

Up to 4 MHz

MCGOUTCLK clock
divider

In all stop modes

System clock

Up to 48 MHz

Up to 4 MHz

MCGOUTCLK clock
divider

In all stop modes and
Compute Operation

Bus clock

Up to 24 MHz

Up to 1 MHz 1

MCGOUTCLK clock
divider

In all stop modes
except for partial
STOP2 mode, and
Compute Operation

SWD Clock

Up to 24MHz

Up to 1MHz

SWD_CLK pin

In all stop modes

Flash clock

Up to 24 MHz

Up to 1 MHz in BLPE

MCGOUTCLK clock
divider

In all stop modes
except for partial
STOP2 mode

MCG

MCG_C1[IRCLKEN]
cleared,

Up to 800 kHz in BLPI
Internal reference
(MCGIRCLK)

30-40 kHz Slow IRC

4 MHz Fast IRC only

or 4 MHz Fast IRC

Stop/VLPS mode and
MCG_C1[IREFSTEN]
cleared, or
LLS/VLLS mode
External reference
(OSCERCLK)

Up to 48 MHz (bypass), Up to 16 MHz (bypass), System OSC
30-40 kHz
or
3-32 MHz (crystal)

System OSC's
OSC_CR[ERCLKEN]
cleared, or

30-40 kHz (low-range
crystal)

Stop mode and
OSC_CR[EREFSTEN]
cleared

or
3-16 MHz (high-range
crystal)

External reference
32kHz

30-40 kHz

30-40 kHz

or VLLS0 and oscillator
not in external clock
mode.
System OSC

System OSC's
OSC_CR[ERCLKEN]
cleared

, or RTC_CLKIN

(ERCLK32K)

and RTC's
RTC_CR[OSCE]
cleared
or VLLS0 and oscillator
not in external clock
mode.
RTC_CLKOUT
LPO
TPM clock

RTC 1Hz,

RTC 1Hz,

RTC 1Hz,

Clock is disabled in LLS
and VLLSx modes

OSCERCLK

OSCERCLK

OSCERCLK

1 kHz

1 kHz

PMC

in VLLS0

Up to 48 MHz

Up to 4 MHz

MCGIRCLK,
MCGPLLCLK/2,
MCGFLLCLK, or

SIM_SOPT2[TPMSRC
]=00 or selected clock
source disabled.

OSCERCLK
Table continues on the next page...

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Chapter 5 Clock Distribution

Table 5-1. Clock Summary (continued)
Clock name
UART0 clock

Run mode

VLPR mode

clock frequency

clock frequency

Up to 48 MHz

Up to 4 MHz

Clock source

Clock is disabled
when…

MCGIRCLK,
MCGPLLCLK/2,
MCGFLLCLK, or

SIM_SOPT2[UART0SR
C]=00 or selected clock
source disabled.

OSCERCLK
USB FS clock

48 MHz

N/A

MCGPLLCLK/2 or
MCGFLLCLK, or

USB FS OTG is
disabled

USB_CLKIN
1. If in BLPI mode, where clocking is derived from the fast internal reference clock, the Bus clock and flash clock frequency
needs to be limited to 800 kHz if executing from flash.

5.5 Internal clocking requirements
The clock dividers are programmed via the SIM module’s CLKDIV registers. The
following requirements must be met when configuring the clocks for this device:
1. The core, platform, and system clock are programmable from a divide-by-1 through
divide-by-16 setting. The core, platform, and system clock frequencies must be 48
MHz or slower.
2. The bus clock and flash clock frequency is divided from the system clock and is
programmable from a divide-by-1 through divide-by-8 setting. The bus clock and
flash clock must be programmed to 24 MHz or slower.
The following is a common clock configuration for this device:
Clock

Frequency

Core clock

48 MHz

Platform clock

48 MHz

System clock

48 MHz

Bus clock

24 MHz

Flash clock

24 MHz

5.5.1 Clock divider values after reset
Each clock divider is programmed via the SIM module’s CLKDIV1 registers. Two bits in
the flash memory's FTFA_FOPT register controls the reset value of the core clock,
system clock, bus clock, and flash clock dividers as shown below:

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Internal clocking requirements

FTFA_FOPT [4,0]

Core/system clock

Bus/Flash clock

Description

00

0x7 (divide by 8)

0x1 (divide by 2)

Low power boot

01

0x3 (divide by 4)

0x1 (divide by 2)

Low power boot

10

0x1 (divide by 2)

0x1 (divide by 2)

Low power boot

11

0x0 (divide by 1)

0x1 (divide by 2)

Fast clock boot

This gives the user flexibility in selecting between a lower frequency, low-power boot
option vs. higher frequency, higher power during and after reset.
The flash erased state defaults to fast clocking mode, since these bits reside in flash,
which is logic 1 in the flash erased state. To enable a lower power boot option, program
the appropriate bits in FTFA_FOPT. During the reset sequence, if either of the control
bits is cleared, the system is in a slower clock configuration. Upon any system reset, the
clock dividers return to this configurable reset state.

5.5.2 VLPR mode clocking
The clock dividers cannot be changed while in VLPR mode. They must be programmed
prior to entering VLPR mode to guarantee operation. Max frequency limitations for
VLPR mode is as follows :
• the core/system clocks are less than or equal to 4 MHz, and
• the bus and flash clocks are less than or equal to 1 MHz
NOTE
When the MCG is in BLPI and clocking is derived from the
Fast IRC, the clock divider controls (MCG_SC[FCRDIV],
SIM_CLKDIV1[OUTDIV1], and SIM_CLKDIV1[OUTDIV4])
must be programmed such that the resulting flash clock nominal
frequency is 800 kHz or less. In this case, one example of
correct configuration is MCG_SC[FCRDIV]=000b,
SIM_CLKDIV1[OUTDIV1]=0000b and
SIM_CLKDIV1[OUTDIV4]=100b, resulting in a divide by 5
setting.

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Chapter 5 Clock Distribution

5.6 Clock Gating
The clock to each module can be individually gated on and off using the SIM module's
SCGCx registers. These bits are cleared after any reset, which disables the clock to the
corresponding module to conserve power. Prior to initializing a module, set the
corresponding bit in SCGCx register to enable the clock. Before turning off the clock,
make sure to disable the module.
Any bus access to a peripheral that has its clock disabled generates an error termination.

5.7 Module clocks
The following table summarizes the clocks associated with each module.
Table 5-2. Module clocks
Module

Bus interface clock

Internal clocks

I/O interface clocks

Core modules
ARM Cortex-M0+ core

Platform clock

Core clock

—

NVIC

Platform clock

—

—

DAP

Platform clock

—

SWD_CLK

System modules
DMA

System clock

—

—

DMA Mux

Bus clock

—

—

Port control

Bus clock

—

—

Crossbar Switch

Platform clock

—

—

Peripheral bridges

System clock

Bus clock

—

LLWU, PMC, SIM, RCM

Bus clock

LPO

—

Mode controller

Bus clock

—

—

MCM

Platform clock

—

—

Watchdog timer

Bus clock

LPO

—

MCG

Bus clock

MCGOUTCLK, MCGPLLCLK,
MCGFLLCLK, MCGIRCLK,
OSCERCLK

—

OSC

Bus clock

OSCERCLK

—

Clocks

Memory and memory interfaces
Flash Controller

Platform clock

Flash clock

—

Flash memory

Flash clock

—

—

Analog
Table continues on the next page...

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Module clocks

Table 5-2. Module clocks (continued)
Module

Bus interface clock

Internal clocks

I/O interface clocks

ADC

Bus clock

OSCERCLK

—

CMP

Bus clock

—

—

DAC

Bus clock

—

—

Timers
TPM

Bus clock

TPM clock

TPM_CLKIN0, TPM_CLKIN1

PIT

Bus clock

—

—

LPTMR

Bus clock

LPO, OSCERCLK,
MCGIRCLK, ERCLK32K

—

RTC

Bus clock

ERCLK32K

RTC_CLKOUT

Communication interfaces
USB FS OTG

System clock

USB FS clock

—

SPI0

Bus clock

—

SPI0_SCK

SPI1

System clock

—

SPI1_SCK

I2C0

Bus clock

—

I2C0_SCL

I2C1

Bus clock

—

I2C1_SCL

UART0

Bus clock

UART0 clock

—

UART1 , UART2

Bus clock

—

—

Human-machine interfaces
GPIO

Platform clock

—

—

TSI

Bus clock

—

—

5.7.1 PMC 1-kHz LPO clock
The Power Management Controller (PMC) generates a 1-kHz clock that is enabled in all
modes of operation, including all low power modes except VLLS0. This 1-kHz source is
commonly referred to as LPO clock or 1-kHz LPO clock.

5.7.2 COP clocking
The COP may be clocked from two clock sources as shown in the following figure.

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Chapter 5 Clock Distribution

LPO
COP clock

Bus clock

SIM_COPCTRL[COPCLKS]

Figure 5-2. COP clock generation

5.7.3 RTC clocking
The RTC module can be clocked as shown in the following figure.
NOTE
The chosen clock must remain enabled if the RTC is to
continue operating in all required low-power modes.

LPO
ERCLK32K
(to RTC)

RTC_CLKIN
OSC32KCLK

SIM_SOPT1[OSC32KSEL]

Figure 5-3. RTC clock generation

5.7.4 LPTMR clocking
The prescaler and glitch filters in each of the LPTMRx modules can be clocked as shown
in the following figure.
NOTE
The chosen clock must remain enabled if the LPTMRx is to
continue operating in all required low-power modes.
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Module clocks

MCGIRCLK
LPO

LPO

LPTMRx prescaler/glitch
filter clock

ERCLK32K

RTC_CLKIN

OSCERCLK

OSC32KCLK

SIM_SOPT1[OSC32KSEL]

LPTMRx_PSR[PCS]

Figure 5-4. LPTMRx prescaler/glitch filter clock generation

5.7.5 TPM clocking
The counter for the TPM modules have a selectable clock as shown in the following
figure.
NOTE
The chosen clock must remain enabled if the TPMx is to
continue operating in all required low-power modes.

MCGIRCLK

OSCERCLK

TPM clock

MCGFLLCLK
MCGPLLCLK

÷2
SIM_SOPT2[PLLFLLSEL] SIM_SOPT2[TPMSRC]

Figure 5-5. TPM clock generation

5.7.6 USB FS OTG Controller clocking
The USB FS OTG controller is a bus master attached to the crossbar switch. As such, its
clock is connected to the system clock.

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Chapter 5 Clock Distribution

NOTE
For the USB FS OTG controller to operate, the minimum
system clock frequency is 20 MHz.
The USB OTG controller also requires a 48 MHz clock. The clock source options are
shown below.

USB_CLKIN
USB 48MHz
MCGFLLCLK
MCGPLLCLK

÷2
SIM_SOPT2[PLLFLLSEL] SIM_SOPT2[USBSRC]

Figure 5-6. USB 48 MHz clock source

NOTE
The MCGFLLCLK does not meet the USB jitter specifications
for certification.

5.7.7 UART clocking
The UART0 module has a selectable clock as shown in the following figure. UART1 and
UART2 modules operate from the bus clock.
NOTE
The chosen clock must remain enabled if the UART0 is to
continue operating in all required low-power modes.
MCGIRCLK
OSCERCLK

UART0 clock

MCGFLLCLK
MCGPLLCLK

÷2
SIM_SOPT2[PLLFLLSEL]

SIM_SOPT2[UART0SRC]

Figure 5-7. UART0 clock generation
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Chapter 6
Reset and Boot
6.1 Introduction
The following reset sources are supported in this MCU:
Table 6-1. Reset sources
Reset sources
POR reset

Description
• Power-on reset (POR)

System resets

Debug reset

•
•
•
•
•
•
•
•
•
•

External pin reset (PIN)
Low-voltage detect (LVD)
Computer operating properly (COP) watchdog reset
Low leakage wakeup (LLWU) reset
Multipurpose clock generator loss of clock (LOC) reset
Multipurpose clock generator loss of lock (LOL) reset
Stop mode acknowledge error (SACKERR)
Software reset (SW)
Lockup reset (LOCKUP)
MDM DAP system reset

• Debug reset

Each of the system reset sources has an associated bit in the system reset status (SRS)
registers. See the Reset Control Module for register details.
The MCU can exit and reset in functional mode where the CPU is executing code
(default) or the CPU is in a debug halted state. There are several boot options that can be
configured. See Boot information for more details.

6.2 Reset
This section discusses basic reset mechanisms and sources. Some modules that cause
resets can be configured to cause interrupts instead. Consult the individual peripheral
chapters for more information.

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Reset

6.2.1 Power-on reset (POR)
When power is initially applied to the MCU or when the supply voltage drops below the
power-on reset re-arm voltage level (VPOR), the POR circuit causes a POR reset
condition.
As the supply voltage rises, the LVD circuit holds the MCU in reset until the supply has
risen above the LVD low threshold (VLVDL). The POR and LVD bits in reset status
register are set following a POR.

6.2.2 System reset sources
Resetting the MCU provides a way to start processing from a known set of initial
conditions. System reset begins with the on-chip regulator in full regulation and system
clocking generation from an internal reference. When the processor exits reset, it
performs the following:
• Reads the start SP (SP_main) from vector-table offset 0
• Reads the start PC from vector-table offset 4
• LR is set to 0xFFFF_FFFF
The on-chip peripheral modules are disabled and the non-analog I/O pins are initially
configured as disabled. The pins with analog functions assigned to them default to their
analog function after reset.
During and following a reset, the SWD pins have their associated input pins configured
as:
• SWD_CLK in pull-down (PD)
• SWD_DIO in pull-up (PU)

6.2.2.1 External pin reset (RESET)
This pin is open drain and has an internal pullup device. Asserting RESET wakes the
device from any mode.
The RESET pin can be disabled by programming RESET_PIN_CFG option bit to 0.
When this option selected, there could be a short period of contention during a POR ramp
where the device drives the pin out low prior to establishing the setting of this option and
releasing the RESET function on the pin.

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Chapter 6 Reset and Boot

6.2.2.1.1

Reset pin filter

The RESET pin filter supports filtering from both the 1 kHz LPO clock and the bus
clock. The RPFC[RSTFLTSS], RPFC[RSTFLTSRW], and RPFW[RSTFLTSEL] fields
in the reset control (RCM) register set control this functionality; see the RCM chapter.
The filters are asynchronously reset by Chip POR. The reset value for each filter assumes
the RESET pin is negated.
For all stop modes where LPO clock is still active (Stop, VLPS, LLS, VLLS3, and
VLLS1), the only filtering option is the LPO based digital filter. The filtering logic either
switches to bypass operation or has continued filtering operation depending on the
filtering mode selected. When entering VLLS0, the RESET pin filter is disabled and
bypassed.
The LPO filter has a fixed filter value of 3. Due to a synchronizer on the input data, there
is also some associated latency (2 cycles). As a result, 5 cycles are required to complete a
transition from low to high or high to low.

6.2.2.2 Low-voltage detect (LVD)
The chip includes a system for managing low voltage conditions to protect memory
contents and control MCU system states during supply voltage variations. The system
consists of a power-on reset (POR) circuit and an LVD circuit with a user-selectable trip
voltage. The LVD system is always enabled in normal run, wait, or stop mode. The LVD
system is disabled when entering VLPx, LLS, or VLLSx modes.
The LVD can be configured to generate a reset upon detection of a low voltage condition
by setting the PMC's LVDSC1[LVDRE] bit to 1. The low voltage detection threshold is
determined by the PMC's LVDSC1[LVDV] field. After an LVD reset has occurred, the
LVD system holds the MCU in reset until the supply voltage has risen above the low
voltage detection threshold. The RCM's SRS0[LVD] bit is set following either an LVD
reset or POR.

6.2.2.3 Computer operating properly (COP) watchdog timer
The computer operating properly (COP) watchdog timer (WDOG) monitors the operation
of the system by expecting periodic communication from the software. This
communication is generally known as servicing (or refreshing) the COP watchdog. If this
periodic refreshing does not occur, the watchdog issues a system reset. The COP reset
causes the RCM's SRS0[WDOG] bit to set.

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Reset

6.2.2.4 Low leakage wakeup (LLWU)
The LLWU module provides the means for a number of external pins and a number of
internal peripherals to wake the MCU from low leakage power modes. The LLWU
module is functional only in low leakage power modes. In VLLSx modes, all enabled
inputs to the LLWU can generate a system reset.
After a system reset, the LLWU retains the flags indicating the input source of the last
wakeup until the user clears them.
NOTE
Some flags are cleared in the LLWU and some flags are
required to be cleared in the peripheral module. Refer to the
individual peripheral chapters for more information.

6.2.2.5 Multipurpose clock generator loss-of-clock (LOC)
The MCG module supports an external reference clock.
If the C6[CME] bit in the MCG module is set, the clock monitor is enabled. If the
external reference falls below floc_low or floc_high, as controlled by the C2[RANGE] field
in the MCG module, the MCU resets. The RCM's SRS0[LOC] bit is set to indicate this
reset source.
NOTE
To prevent unexpected loss of clock reset events, all clock
monitors must be disabled before entering any low power
modes, including VLPR and VLPW.

6.2.2.6 MCG loss-of-lock (LOL) reset
The MCG includes a PLL loss-of-lock detector. The detector is enabled when configured
for PEE and lock has been achieved. If the MCG_C8[LOLRE] bit in the MCG module is
set and the PLL lock status bit (MCG_S[LOLS0]) becomes set, the MCU resets. The
RCM_SRS0[LOL] bit is set to indicate this reset source.
NOTE
This reset source does not cause a reset if the chip is in any stop
mode.

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Chapter 6 Reset and Boot

6.2.2.7 Stop mode acknowledge error (SACKERR)
This reset is generated if the core attempts to enter stop mode or Compute Operation, but
not all modules acknowledge stop mode within 1025 cycles of the 1 kHz LPO clock.
A module might not acknowledge the entry to stop mode if an error condition occurs. The
error can be caused by a failure of an external clock input to a module.

6.2.2.8 Software reset (SW)
The SYSRESETREQ bit in the NVIC application interrupt and reset control register can
be set to force a software reset on the device. (See ARM's NVIC documentation for the
full description of the register fields, especially the VECTKEY field requirements.)
Setting SYSRESETREQ generates a software reset request. This reset forces a system
reset of all major components except for the debug module. A software reset causes the
RCM's SRS1[SW] bit to set.

6.2.2.9 Lockup reset (LOCKUP)
The LOCKUP gives immediate indication of seriously errant kernel software. This is the
result of the core being locked because of an unrecoverable exception following the
activation of the processor’s built in system state protection hardware.
The LOCKUP condition causes a system reset and also causes the RCM's
SRS1[LOCKUP] bit to set.

6.2.2.10 MDM-AP system reset request
Set the system reset request bit in the MDM-AP control register to initiate a system reset.
This is the primary method for resets via the SWD interface. The system reset is held
until this bit is cleared.
Set the core hold reset bit in the MDM-AP control register to hold the core in reset as the
rest of the chip comes out of system reset.

6.2.3 MCU Resets
A variety of resets are generated by the MCU to reset different modules.
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Reset

6.2.3.1 POR Only
The POR Only reset asserts on the POR reset source only. It resets the PMC and RTC.
The POR Only reset also causes all other reset types to occur.

6.2.3.2 Chip POR not VLLS
The Chip POR not VLLS reset asserts on POR and LVD reset sources. It resets parts of
the SMC and SIM. It also resets the LPTMR.
The Chip POR not VLLS reset also causes these resets to occur: Chip POR, Chip Reset
not VLLS, and Chip Reset (including Early Chip Reset).

6.2.3.3 Chip POR
The Chip POR asserts on POR, LVD, and VLLS Wakeup reset sources. It resets the
Reset Pin Filter registers and parts of the SIM and MCG.
The Chip POR also causes the Chip Reset (including Early Chip Reset) to occur.

6.2.3.4 Chip Reset not VLLS
The Chip Reset not VLLS reset asserts on all reset sources except a VLLS Wakeup that
does not occur via the RESET pin. It resets parts of the SMC, LLWU, and other modules
that remain powered during VLLS mode.
The Chip Reset not VLLS reset also causes the Chip Reset (including Early Chip Reset)
to occur.

6.2.3.5 Early Chip Reset
The Early Chip Reset asserts on all reset sources. It resets only the flash memory module.
It negates before flash memory initialization begins ("earlier" than when the Chip Reset
negates).

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Chapter 6 Reset and Boot

6.2.3.6 Chip Reset
Chip Reset asserts on all reset sources and only negates after flash initialization has
completed and the RESET pin has also negated. It resets the remaining modules (the
modules not reset by other reset types).

6.2.4 Reset Pin
For all reset sources except a VLLS Wakeup that does not occur via the RESET pin, the
RESET pin is driven low by the MCU for at least 128 bus clock cycles and until flash
initialization has completed.
After flash initialization has completed, the RESET pin is released, and the internal Chip
Reset negates after the RESET pin is pulled high. Keeping the RESET pin asserted
externally delays the negation of the internal Chip Reset.
The RESET pin can be disabled by programming RESET_PIN_CFG option bit to 0.
When this option is selected, there could be a short period of contention during a POR
ramp where the device drives the pin out low prior to establishing the setting of this
option and releasing the RESET function on the pin.

6.2.5 Debug resets
The following sections detail the debug resets available on the device.

6.2.5.1 Resetting the Debug subsystem
Use the CDBGRSTREQ bit within the DP CTRL/STAT register to reset the debug
modules. However, as explained below, using the CDBGRSTREQ bit does not reset all
debug-related registers.
CDBGRSTREQ resets the debug-related registers within the following modules:
• SW-DP
• AHB-AP
• MDM-AP (MDM control and status registers)
CDBGRSTREQ does not reset the debug-related registers within the following modules:
• CM0+ core (core debug registers: DHCSR, DCRSR, DCRDR, DEMCR)
• BPU
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Boot

•
•
•
•
•

DWT
NVIC
Crossbar bus switch1
AHB-AP1
Private peripheral bus1

6.3 Boot
This section describes the boot sequence, including sources and options.
Some configuration information such as clock trim values stored in factory programmed
flash locations is autoloaded.

6.3.1 Boot sources
The CM0+ core adds support for a programmable Vector Table Offset Register (VTOR)
to relocate the exception vector table. This device supports booting from internal flash
and RAM.
This device supports booting from internal flash with the reset vectors located at
addresses 0x0 (initial SP_main), 0x4 (initial PC), and RAM with relocating the exception
vector table to RAM.

6.3.2 FOPT boot options
The flash option register (FOPT) in flash memory module (FTFA) allows the user to
customize the operation of the MCU at boot time. The register contains read-only bits
that are loaded from the NVM's option byte in the flash configuration field. The default
setting for all values in the FOPT register is logic 1 since it is copied from the option byte
residing in flash, which has all bits as logic 1 in the flash erased state. To configure for
alternate settings, program the appropriate bits in the NVM option byte. The new settings
will take effect on subsequent POR, VLLSx recoveries, and any system reset. For more
details on programming the option byte, refer to the flash memory chapter.

1.

CDBGRSTREQ does not affect AHB resources so that debug resources on the private peripheral bus are available
during System Reset.

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The MCU uses the FTFA_FOPT register bits to configure the device at reset as shown in
the following table.
Table 6-2. Flash Option Register (FTFA_FOPT) Bit Definitions
Bit
Num

Field

Value

Definition

7-6

Reserved

Reserved for future expansion.

5

FAST_INIT

Select initialization speed on POR, VLLSx, and any system reset .

3

RESET_PIN_CFG

0

Slower initialization. The Flash initialization will be slower with the benefit of
reduced average current during this time. The duration of the recovery will be
controlled by the clock divider selection determined by the LPBOOT setting.

1

Fast Initialization.The Flash has faster recoveries at the expense of higher current
during these times.

Enable/disable control for the RESET pin.
0

RESET pin is disabled following a POR and cannot be enabled as RESET
function. When this option is selected, there could be a short period of contention
during a POR ramp where the device drives the pin out low prior to establishing the
setting of this option and releasing the RESET function on the pin.
This bit is preserved through system resets and low power modes. When RESET
pin function is disabled it cannot be used as a source for low power mode wakeup.

1
2

NMI_DIS

RESET pin is dedicated. The port is configured with pullup enabled, open drain,
passive filter enabled.

Enable/disable control for the NMI function.
0

NMI interrupts are always blocked. The associated pin continues to default to NMI
pin controls with internal pullup enabled. When NMI pin function is disabled it
cannot be used as a source for low power mode wakeup.

1

NMI pin/interrupts reset default to enabled.

1

Reserved

Reserved for future expansion.

4,0

LPBOOT

Control the reset value of OUTDIV1 value in SIM_CLKDIV1 register. Larger divide value
selections produce lower average power consumption during POR, VLLSx recoveries and
reset sequencing and after reset exit. The recovery times are also extended if the
FAST_INIT option is not selected.
00

Core and system clock divider (OUTDIV1) is 0x7 (divide by 8)

01

Core and system clock divider (OUTDIV1) is 0x3 (divide by 4)

10

Core and system clock divider (OUTDIV1) is 0x1 (divide by 2)

11

Core and system clock divider (OUTDIV1) is 0x0 (divide by 1)

6.3.3 Boot sequence
At power up, the on-chip regulator holds the system in a POR state until the input supply
is above the POR threshold. The system continues to be held in this static state until the
internally regulated supplies have reached a safe operating voltage as determined by the
LVD. The Reset Controller logic then controls a sequence to exit reset.

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Boot

1. A system reset is held on internal logic, the RESET pin is driven out low, and the
MCG is enabled in its default clocking mode.
2. Required clocks are enabled (System Clock, Flash Clock, and any Bus Clocks that do
not have clock gate control reset to disabled).
3. The system reset on internal logic continues to be held, but the Flash Controller is
released from reset and begins initialization operation while the Reset Control logic
continues to drive the RESET pin out low.
4. Early in reset sequencing the NVM option byte is read and stored to FTFA_FOPT. If
the bits associated with LPBOOT are programmed for an alternate clock divider reset
value, the system/core clock is switched to a slower clock speed. If the FAST_INIT
bit is programmed clear, the Flash initialization switches to slower clock resulting
longer recovery times.
5. When Flash Initialization completes, the RESET pin is released. If RESET continues
to be asserted (an indication of a slow rise time on the RESET pin or external drive
in low), the system continues to be held in reset. Once the RESET pin is detected
high, the Core clock is enabled and the system is released from reset.
6. When the system exits reset, the processor sets up the stack, program counter (PC),
and link register (LR). The processor reads the start SP (SP_main) from vector-table
offset 0. The core reads the start PC from vector-table offset 4. LR is set to
0xFFFF_FFFF. The CPU begins execution at the PC location.
Subsequent system resets follow this same reset flow.

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Chapter 7
Power Management
7.1 Introduction
This chapter describes the various chip power modes and functionality of the individual
modules in these modes.

7.2 Clocking Modes
This sections describes the various clocking modes supported on this device.

7.2.1 Partial Stop
Partial Stop is a clocking option that can be taken instead of entering STOP mode and is
configured in the SMC Stop Control Register (SMC_STOPCTRL). The Stop mode is
only partially entered, which leaves some additional functionality alive at the expense of
higher power consumption. Partial Stop can be entered from either Run mode or VLP
Run mode.
When configured for PSTOP2, only the core and system clocks are gated and the bus
clock remains active. The bus masters and bus slaves clocked by the system clock enter
Stop mode, but the bus slaves clocked by bus clock remain in Run (or VLP Run) mode.
The clock generators in the MCG and the on-chip regulator in the PMC also remain in
Run (or VLP Run) mode. Exit from PSTOP2 can be initiated by a reset, an asynchronous
interrupt from a bus master or bus slave clocked by the system clock, or a synchronous
interrupt from a bus slave clocked by the bus clock. If configured, a DMA request (using
the asynchronous DMA wakeup) can also be used to exit Partial Stop for the duration of a
DMA transfer before the device is transitioned back into PSTOP2.

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Clocking Modes

When configured for PSTOP1, both the system clock and bus clock are gated. All bus
masters and bus slaves enter Stop mode, but the clock generators in the MCG and the onchip regulator in the PMC remain in Run (or VLP Run) mode. Exit from PSTOP1 can be
initiated by a reset or an asynchronous interrupt from a bus master or bus slave. If
configured, an asynchronous DMA request can also be used to exit Partial Stop for the
duration of a DMA transfer before the device is transitioned back into PSTOP1.
PSTOP1 is functionally similar to STOP mode, but offers faster wakeup at the expense of
higher power consumption. Another benefit is that it keeps all of the MCG clocks
enabled, which can be useful for some of the asynchronous peripherals that can remain
functional in Stop modes.

7.2.2 DMA Wakeup
The DMA can be configured to wakeup the device on a DMA request whenever it is
placed in stop mode. The wakeup is configured per DMA channel and is supported in
Compute Operation, PSTOP, STOP and VLPS low power modes.
When a DMA wakeup is detected in PSTOP, STOP or VLPS then the device will initiate
a normal exit from the low power mode. This can include restoring the on-chip regulator
and internal power switches, enabling the clock generators in the MCG, enabling the
system and bus clocks (but not the core clock) and negating the stop mode signal to the
bus masters and bus slaves. The only difference is that the CPU will remain in the low
power mode with the CPU clock disabled.
During Compute Operation, a DMA wakeup will initiate a normal exit from Compute
Operation. This includes enabling the clocks and negating the stop mode signal to the bus
masters and bus slaves. The core clock always remains enabled during Compute
Operation.
Since the DMA wakeup will enable the clocks and negate the stop mode signals to all bus
masters and slaves, software needs to ensure that bus masters and slaves that are not
involved with the DMA wakeup and transfer remain in a known state. That can be
accomplished by disabling the modules before entry into the low power mode or by
setting the Doze enable bit in selected modules.
Once the DMA request that initiated the wakeup negates and the DMA completes the
current transfer, the device will transition back into the original low power mode. This
includes requesting all non-CPU bus masters to enter Stop mode and then requesting bus
slaves to enter Stop mode. In STOP and VLPS modes the MCG and PMC would then
also enter their appropriate modes.

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Chapter 7 Power Management

NOTE
If the requested DMA transfer cannot cause the DMA request
to negate then the device will remain in a higher power state
until the low power mode is fully exited.
An enabled DMA wakeup can cause an aborted entry into the low power mode, if the
DMA request asserts during the stop mode entry sequence (or reentry if the request
asserts during a DMA wakeup) and can cause the SMC to assert its Stop Abort flag. Once
the DMA wakeup completes, entry into the low power mode will restart.
An interrupt that occurs during a DMA wakeup will cause an immediate exit from the
low power mode (this is optional for Compute Operation) without impacting the DMA
transfer.
A DMA wakeup can be generated by either a synchronous DMA request or an
asynchronous DMA request. Not all peripherals can generate an asynchronous DMA
request in stop modes, although in general if a peripheral can generate synchronous DMA
requests and also supports asynchronous interrupts in stop modes, then it can generate an
asynchronous DMA request.

7.2.3 Compute Operation
Compute Operation is an execution or compute-only mode of operation that keeps the
CPU enabled with full access to the SRAM and Flash read port, but places all other bus
masters and bus slaves into their stop mode. Compute Operation can be enabled in either
Run mode or VLP Run mode.
NOTE
Do not enter any stop mode without first exiting Compute
Operation.
Because Compute Operation reuses the stop mode logic (including the staged entry with
bus masters disabled before bus slaves), any bus master or bus slave that can remain
functional in stop mode also remains functional in Compute Operation, including
generation of asynchronous interrupts and DMA requests. When enabling Compute
Operation in Run mode, module functionality for bus masters and slaves is the equivalent
of STOP mode. When enabling Compute Operation in VLP Run mode, module
functionality for bus masters and slaves is the equivalent of VLPS mode. The MCG,
PMC, SRAM and Flash read port are not affected by Compute Operation, although the
Flash register interface is disabled.

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Clocking Modes

During Compute Operation, the AIPS peripheral space is disabled and attempted accesses
generate bus errors. The private peripheral space remains accessible during Compute
Operation, including the MCM, NVIC, IOPORT and SysTick. Although access to the
GPIO registers via the IOPORT is supported, the GPIO port data input registers do not
return valid data since clocks are disabled to the Port Control and Interrupt modules. By
writing to the GPIO port data output registers, it is possible to control those GPIO ports
that are configured as output pins.
Compute Operation is controlled by the CPO register in the MCM, which is only
accessible to the CPU. Setting or clearing the CPOREQ bit in the MCM initiates entry or
exit into Compute Operation. Compute Operation can also be configured to exit
automatically on detection of an interrupt, which is required in order to service most
interrupts. Only the core system interrupts (exceptions, including NMI and SysTick) and
any edge sensitive interrupts can be serviced without exiting Compute Operation.
When entering Compute Operation, the CPOACK status bit indicates when entry has
completed. When exiting Compute Operation in Run mode, the CPOACK status bit
negates immediately. When exiting Compute Operation in VLP Run mode, the exit is
delayed to allow the PMC to handle the change in power consumption. This delay means
the CPOACK bit is polled to determine when the AIPS peripheral space can be accessed
without generating a bus error.
The DMA wakeup is also supported during Compute Operation and causes the CPOACK
status bit to clear and the AIPS peripheral space to be accessible for the duration of the
DMA wakeup. At the completion of the DMA wakeup, the device transitions back into
Compute Operation.

7.2.4 Peripheral Doze
Several peripherals support a peripheral Doze mode, where a register bit can be used to
disable the peripheral for the duration of a low power mode. The Flash can also be placed
in a low power state during Peripheral Doze via a register bit in the SIM.
Peripheral Doze is defined to include all of the modes of operation listed below.
• The CPU is in wait mode.
• The CPU is in stop mode, including the entry sequence and for the duration of a
DMA wakeup.
• The CPU is in Compute Operation, including the entry sequence and for the duration
of a DMA wakeup.

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Chapter 7 Power Management

Peripheral Doze can therefore be used to disable selected bus masters or slaves for the
duration of WAIT or VLPW mode. It can also be used to disable selected bus slaves
immediately on entry into any stop mode (or Compute Operation), instead of waiting for
the bus masters to acknowledge the entry as part of the stop entry sequence. Finally, it
can be used to disable selected bus masters or slaves that should remain inactive during a
DMA wakeup.
If the Flash is not being accessed during WAIT and PSTOP modes, then the Flash Doze
mode can be used to reduce power consumption, at the expense of a slightly longer
wakeup when executing code and vectors from Flash. It can also be used to reduce power
consumption during Compute Operation when executing code and vectors from SRAM.

7.2.5 Clock Gating
To conserve power, the clocks to most modules can be turned off using the SCGCx
registers in the SIM module. These bits are cleared after any reset, which disables the
clock to the corresponding module. Prior to initializing a module, set the corresponding
bit in the SCGCx register to enable the clock. Before turning off the clock, make sure to
disable the module. For more details, refer to the clock distribution and SIM chapters.

7.3 Power modes
The power management controller (PMC) provides multiple power options to allow the
user to optimize power consumption for the level of functionality needed.
Depending on the stop requirements of the user application, a variety of stop modes are
available that provide state retention, partial power down or full power down of certain
logic and/or memory. I/O states are held in all modes of operation. The following table
compares the various power modes available.
For each run mode there is a corresponding wait and stop mode. Wait modes are similar
to ARM sleep modes. Stop modes (VLPS, STOP) are similar to ARM sleep deep mode.
The very low power run (VLPR) operating mode can drastically reduce runtime power
when the maximum bus frequency is not required to handle the application needs.

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Power modes

The three primary modes of operation are run, wait and stop. The WFI instruction
invokes both wait and stop modes for the chip. The primary modes are augmented in a
number of ways to provide lower power based on application needs.
Table 7-1. Chip power modes
Chip mode

Description

Normal run

Allows maximum performance of chip. Default mode out of reset; onchip voltage regulator is on.

Core mode

Normal
recovery
method

Run

—

Normal Wait via WFI

Allows peripherals to function while the core is in sleep mode, reducing
power. NVIC remains sensitive to interrupts; peripherals continue to be
clocked.

Sleep

Interrupt

Normal Stop via WFI

Places chip in static state. Lowest power mode that retains all registers
while maintaining LVD protection. NVIC is disabled; AWIC is used to
wake up from interrupt; peripheral clocks are stopped.

Sleep Deep

Interrupt

Run

—

Sleep

Interrupt

Sleep Deep

Interrupt

Sleep Deep

Wakeup
Interrupt1

Sleep Deep

Wakeup Reset2

VLPR (Very Low On-chip voltage regulator is in a low power mode that supplies only
Power Run)
enough power to run the chip at a reduced frequency. Reduced
frequency Flash access mode (1 MHz); LVD off; in BLPI clock mode,
the fast internal reference oscillator is available to provide a low power
nominal 4MHz source for the core with the nominal bus and flash clock
required to be <800kHz; alternatively, BLPE clock mode can be used
with an external clock or the crystal oscillator providing the clock
source.
VLPW (Very
Low Power
Wait) -via WFI

Same as VLPR but with the core in sleep mode to further reduce
power; NVIC remains sensitive to interrupts (FCLK = ON). On-chip
voltage regulator is in a low power mode that supplies only enough
power to run the chip at a reduced frequency.

VLPS (Very Low Places chip in static state with LVD operation off. Lowest power mode
Power Stop)-via with ADC and pin interrupts functional. Peripheral clocks are stopped,
WFI
but OSC, LPTMR, RTC, CMP, TSI can be used. TPM and UART can
optionally be enabled if their clock source is enabled. NVIC is disabled
(FCLK = OFF); AWIC is used to wake up from interrupt. On-chip
voltage regulator is in a low power mode that supplies only enough
power to run the chip at a reduced frequency. All SRAM is operating
(content retained and I/O states held).
LLS (Low
State retention power mode. Most peripherals are in state retention
Leakage Stop) mode (with clocks stopped), but OSC, LLWU, LPTMR, RTC, CMP,,
TSI can be used. NVIC is disabled; LLWU is used to wake up.
NOTE: The LLWU interrupt must not be masked by the interrupt
controller to avoid a scenario where the system does not fully
exit stop mode on an LLS recovery.
All SRAM is operating (content retained and I/O states held).
VLLS3 (Very
Low Leakage
Stop3)

Most peripherals are disabled (with clocks stopped), but OSC, LLWU,
LPTMR, RTC, CMP, TSI can be used. NVIC is disabled; LLWU is used
to wake up.
SRAM_U and SRAM_L remain powered on (content retained and I/O
states held).
Table continues on the next page...

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Chapter 7 Power Management

Table 7-1. Chip power modes (continued)
Chip mode

Description

Core mode

Normal
recovery
method

VLLS1 (Very
Low Leakage
Stop1)

Most peripherals are disabled (with clocks stopped), but OSC, LLWU,
LPTMR, RTC, CMP, TSI can be used. NVIC is disabled; LLWU is used
to wake up.

Sleep Deep

Wakeup Reset2

VLLS0 (Very
Low Leakage
Stop 0)

Most peripherals are disabled (with clocks stopped), but LLWU,
LPTMR, RTC, TSI can be used. NVIC is disabled; LLWU is used to
wake up.

Sleep Deep

Wakeup Reset2

All of SRAM_U and SRAM_L are powered off.

All of SRAM_U and SRAM_L are powered off.
LPO disabled, optional POR brown-out detection
1. Resumes normal run mode operation by executing the LLWU interrupt service routine.
2. Follows the reset flow with the LLWU interrupt flag set for the NVIC.

7.4 Entering and exiting power modes
The WFI instruction invokes wait and stop modes for the chip. The processor exits the
low-power mode via an interrupt. For LLS and VLLS modes, the wakeup sources are
limited to LLWU generated wakeups, NMI pin, or RESET pin assertions. When the NMI
pin or RESET pin have been disabled through associated FOPT settings, then these pins
are ignored as wakeup sources. The wake-up flow from VLLSx is always through reset.
NOTE
The WFE instruction can have the side effect of entering a lowpower mode, but that is not its intended usage. See ARM
documentation for more on the WFE instruction.
On VLLS recoveries, the I/O pins continue to be held in a static state after code execution
begins, allowing software to reconfigure the system before unlocking the I/O. RAM is
retained in VLLS3 only.

7.5 Module Operation in Low Power Modes
The following table illustrates the functionality of each module while the chip is in each
of the low power modes. The standard behavior is shown with some exceptions for
Compute Operation (CPO) and Partial Stop2 (PSTOP2).

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Module Operation in Low Power Modes

(Debug modules are discussed separately; see Debug in Low Power Modes.) Number
ratings (such as 4 MHz and 1 Mbps) represent the maximum frequencies or maximum
data rates per mode. Also, these terms are used:
• FF = Full functionality. In VLPR and VLPW the system frequency is limited, but if a
module does not have a limitation in its functionality, it is still listed as FF.
• Async operation = Fully functional with alternate clock source, provided the selected
clock source remains enabled
• static = Module register states and associated memories are retained.
• powered = Memory is powered to retain contents.
• low power = Memory is powered to retain contents in a lower power state
• OFF = Modules are powered off; module is in reset state upon wakeup. For clocks,
OFF means disabled.
• wakeup = Modules can serve as a wakeup source for the chip.
Table 7-2. Module operation in low power modes
Modules

VLPR

VLPW

Stop

VLPS

LLS

VLLSx

static

static

OFF

Core modules
NVIC

FF

FF

static
System modules

Mode Controller

FF

FF

FF

FF

FF

FF

static

static

static

static

FF

FF2

low power

low power

ON

low power

low power

low power in
VLLS3, OFF in
VLLS0/1

disabled

disabled

ON

disabled

disabled

disabled

Brown-out
Detection

ON

ON

ON

ON

ON

ON in VLLS1/3,
optionally
disabled in
VLLS03

DMA

FF

FF

static

OFF

static

static

OFF

ON

ON in VLLS1/3,
OFF in VLLS0

LLWU1
Regulator

LVD

Async operation Async operation

Async operation
in CPO
Watchdog

FF

FF

static in CPO

static
FF in PSTOP2
Clocks

1kHz LPO
System
oscillator (OSC)

ON

ON

ON

ON

OSCERCLK
max of 16MHz
crystal

OSCERCLK
max of 16MHz
crystal

OSCERCLK
optional

OSCERCLK
max of 16MHz
crystal

limited to low
limited to low
range/low power range/low power
in VLLS1/3, OFF
in VLLS0

Table continues on the next page...

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Chapter 7 Power Management

Table 7-2. Module operation in low power modes (continued)
Modules

VLPR

VLPW

Stop

VLPS

LLS

VLLSx

MCG

4 MHz IRC

4 MHz IRC

static MCGIRCLK
optional; PLL
optional

static MCGIRCLK
optional

static - no clock
output

OFF

Core clock

4 MHz max

OFF

OFF

OFF

OFF

OFF

Platform clock

4 MHz max

4 MHz max

OFF

OFF

OFF

OFF

System clock

4 MHz max

4 MHz max

OFF

OFF

OFF

OFF

1 MHz max

OFF

OFF

OFF

OFF

OFF in CPO
Bus clock

1 MHz max
OFF in CPO

24 MHz max in
PSTOP2 from
RUN
1 MHz max in
PSTOP2 from
VLPR
Memory and memory interfaces

Flash

1 MHz max
access - no
program

low power

low power

low power

OFF

OFF

low power

low power

low power

low power

low power in
VLLS3, OFF in
VLLS0/1

No register
access in CPO
SRAM_U and
SRAM_L

low power

Communication interfaces
USB FS/LS

static

static

static

static

static

OFF

USB Voltage
Regulator

optional

optional

optional

optional

optional

optional

UART0

1 Mbps

1 Mbps

static

OFF

static, wakeup
on edge

static

OFF

static, slave
mode receive

static

OFF

Async operation
in CPO
UART1 , UART2

62.5 kbps

FF in PSTOP2
62.5 kbps

static, wakeup
on edge in CPO
SPI0

master mode
500 kbps,

Async operation Async operation

static, wakeup
on edge
FF in PSTOP2

master mode
500 kbps,

slave mode 250 slave mode 250
kbps
kbps

static, slave
mode receive
FF in PSTOP2

static, slave
mode receive in
CPO
Table continues on the next page...

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Module Operation in Low Power Modes

Table 7-2. Module operation in low power modes (continued)
Modules
SPI1

VLPR

VLPW

Stop

VLPS

LLS

VLLSx

master mode 2
Mbps,

master mode 2
Mbps,

static, slave
mode receive

static, slave
mode receive

static

OFF

slave mode 1
Mbps

slave mode 1
Mbps

static, address
match wakeup

static, address
match wakeup

static

OFF

static, address
match wakeup

static

OFF

static

OFF

static

OFF

static, slave
mode receive in
CPO
I2C0

50 kbps

50 kbps

static, address
match wakeup
in CPO
I2C1

50 kbps

FF in PSTOP2
50 kbps

static, address
match wakeup
in CPO

static, address
match wakeup

Timers
TPM

FF

FF

Async operation
in CPO
PIT

FF

Async operation Async operation
FF in PSTOP2

FF

static

static

static in CPO
LPTMR

FF

FF

Async operation Async operation Async operation
FF in PSTOP2

RTC

FF

FF

Async operation
in CPO

Async operation Async operation Async operation
FF in PSTOP2

Async
operation4
Async
operation5

Analog
16-bit ADC

FF

FF

ADC internal
clock only in
CPO
CMP6

FF

FF

FF

FF

static

OFF

HS or LS
compare

HS or LS
compare

LS compare

LS compare in
VLLS1/3, OFF in
VLLS0

static

static

static, OFF in
VLLS0

static

static

static

static output,
wakeup input

static, pins
latched

OFF, pins
latched

FF in PSTOP2
FF

static in CPO
12-bit DAC

ADC internal
clock only

FF in PSTOP2

HS or LS
compare in CPO
6-bit DAC

ADC internal
clock only

static
FF in PSTOP2

FF

static in CPO

static
FF in PSTOP2
Human-machine interfaces

GPIO

FF
IOPORT write
only in CPO

FF

static output,
wakeup input
FF in PSTOP2

Table continues on the next page...

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Chapter 7 Power Management

Table 7-2. Module operation in low power modes (continued)
Modules
TSI

VLPR

VLPW

Stop

VLPS

LLS

VLLSx

FF

Async
operation7

Async
operation7

Async
operation7

Async
operation7

Async
operation7

Async operation
in CPO

FF in PSTOP2

1. Using the LLWU module, the external pins available for this chip do not require the associated peripheral function to be
enabled. It only requires the function controlling the pin (GPIO or peripheral) to be configured as an input to allow a
transition to occur to the LLWU.
2. Since LPO clock source is disabled, filters will be bypassed during VLLS0.
3. The STOPCTRL[PORPO] bit in the SMC module controls this option.
4. LPO clock source is not available in VLLS0. Also, to use system OSC in VLLS0 it must be configured for bypass (external
clock) operation. Pulse counting is available in all modes.
5. In VLLS0 the only clocking option is from RTC_CLKIN.
6. CMP in stop or VLPS supports high speed or low speed external pin to pin or external pin to DAC compares. CMP in LLS
or VLLSx only supports low speed external pin to pin or external pin to DAC compares. Windowed, sampled & filtered
modes of operation are not available while in stop, VLPS, LLS, or VLLSx modes.
7. TSI wakeup from all low power modes is limited to a single selectable pin.

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Chapter 8
Security
8.1 Introduction
This device implements security based on the mode selected from the flash module. The
following sections provide an overview of flash security and details the effects of security
on non-flash modules.

8.2 Flash Security
The flash module provides security information to the MCU based on the state held by
the FSEC[SEC] bits. The MCU, in turn, confirms the security request and limits access to
flash resources. During reset, the flash module initializes the FSEC register using data
read from the security byte of the flash configuration field.
NOTE
The security features apply only to external accesses: debug.
CPU accesses to the flash are not affected by the status of
FSEC.
In the unsecured state all flash commands are available on the programming interfaces
either from the debug port (SWD) or user code execution. When the flash is secured
(FSEC[SEC] = 00, 01, or 11), the programmer interfaces are only allowed to launch mass
erase operations. Additionally, in this mode, the debug port has no access to memory
locations.

8.3 Security Interactions with other Modules
The flash security settings are used by the system to determine what resources are
available. The following sections describe the interactions between modules and the flash
security settings or the impact that the flash security has on non-flash modules.
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Security Interactions with other Modules

8.3.1 Security Interactions with Debug
When flash security is active the SWD port cannot access the memory resources of the
MCU.
Although most debug functions are disabled, the debugger can write to the Flash Mass
Erase in Progress bit to trigger a mass erase (Erase All Blocks) command. A mass erase
via the debugger is allowed even when some memory locations are protected.
When mass erase is disabled, mass erase via the debugger is blocked.

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Chapter 9
Debug
9.1 Introduction
This device's debug is based on the ARM CoreSightTM architecture and is configured to
provide the maximum flexibility as allowed by the restrictions of the pinout and other
available resources.
It provides register and memory accessibility from the external debugger interface, basic
run/halt control plus 2 breakpoints and 2 watchpoints.
Only one debug interface is supported:
• Serial Wire Debug (SWD)

9.2 Debug Port Pin Descriptions
The debug port pins default after POR to their SWD functionality.
Table 9-1. Serial wire debug pin description
Pin Name

Type

Description

SWD_CLK

Input

Serial Wire Clock. This pin is the clock for debug logic when in the Serial
Wire Debug mode. This pin is pulled down internally.

SWD_DIO

Input / Output

Serial wire debug data input/output. The SWD_DIO pin is used by an
external debug tool for communication and device control. This pin is
pulled up internally.

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SWD status and control registers

9.3 SWD status and control registers
Through the ARM Debug Access Port (DAP), the debugger has access to the status and
control elements, implemented as registers on the DAP bus as shown in the following
figure. These registers provide additional control and status for low power mode recovery
and typical run-control scenarios. The status register bits also provide a means for the
debugger to get updated status of the core without having to initiate a bus transaction
across the crossbar switch, thus remaining less intrusive during a debug session.
It is important to note that these DAP control and status registers are not memory mapped
within the system memory map and are only accessible via the Debug Access Port using
SWD. The MDM-AP is accessible as Debug Access Port 1 with the available registers
shown in the table below.
Table 9-2. MDM-AP Register Summary
Address

Register

Description

0x0100_0000

Status

See MDM-AP Status Register

0x0100_0004

Control

See MDM-AP Control Register

0x0100_00FC

IDR

Read-only identification register that
always reads as 0x001C_0020

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Chapter 9 Debug
DPACC

APACC
A[3:2] RnW

Debug Port

0x0C

SW-DP
See the ARM Debug Interface v5p1 Supplement.

Bus Matrix

Status

MDM-AP

SELECT[7:4] (APBANKSEL) selects the bank
A[3:2] from the APACC selects the register
within the bank

SELECT[31:24] = 0x00 selects the AHB-AP
See ARM documentation for further details

Access Port

(AHB-AP)

IDR

AHB Access Port

SELECT[31:24] (APSEL) selects the AP

AHB-AP

0x3F

A[7:4] A[3:2] RnW

0x00

Data[31:0]

0x01

APSEL
Decode

Internal Bus

Generic
Debug Port
(DP)

Control

0x08

Data[31:0]

Read Buffer (RDBUFF)

AP Select (SELECT)

0x04

A[3:2] RnW

Control/Status (CTRL/STAT)

Debug Port ID Register (IDCODE)

DP Registers

0x00

Data[31:0]

See Control and Status Register
Descriptions

MDM-AP
SELECT[31:24] = 0x01 selects the MDM-AP
SELECT[7:4] = 0x0 selects the bank with Status and Ctrl
A[3:2] = 2’b00 selects the Status Register
A[3:2] = 2’b01 selects the Control Register
SELECT[7:4] = 0xF selects the bank with IDR
A[3:2] = 2’b11 selects the IDR Register
(IDR register reads 0x001C_0020)

Figure 9-1. MDM AP Addressing

9.3.1 MDM-AP Control Register
Table 9-3. MDM-AP Control register assignments
Bit
0

Name
Flash Mass Erase in Progress

Secure1
Y

Description
Set to cause mass erase. Cleared by hardware after mass erase
operation completes.
When mass erase is disabled (via MEEN and SEC settings), the erase
request does not occur and the Flash Mass Erase in Progress bit
continues to assert until the next system reset.

1

Debug Disable

N

Set to disable debug. Clear to allow debug operation. When set it
overrides the C_DEBUGEN bit within the DHCSR and force disables
Debug logic.
Table continues on the next page...

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SWD status and control registers

Table 9-3. MDM-AP Control register assignments (continued)
Bit
2

Name
Debug Request

Secure1
N

Description
Set to force the core to halt.
If the core is in a stop or wait mode, this bit can be used to wakeup the
core and transition to a halted state.

3

System Reset Request

Y

Set to force a system reset. The system remains held in reset until this
bit is cleared.

4

Core Hold Reset

N

Configuration bit to control core operation at the end of system reset
sequencing.
0 Normal operation - release the core from reset along with the rest of
the system at the end of system reset sequencing.
1 Suspend operation - hold the core in reset at the end of reset
sequencing. Once the system enters this suspended state, clearing
this control bit immediately releases the core from reset and CPU
operation begins.

5

VLLSx Debug Request
(VLLDBGREQ)

N

Set to configure the system to be held in reset after the next recovery
from a VLLSx mode. This bit is ignored on a VLLS wakeup via the
Reset pin. During a VLLS wakeup via the Reset pin, the system can be
held in reset by holding the reset pin asserted allowing the debugger to
re-initialize the debug modules.
This bit holds the system in reset when VLLSx modes are exited to
allow the debugger time to re-initialize debug IP before the debug
session continues.
The Mode Controller captures this bit logic on entry to VLLSx modes.
Upon exit from VLLSx modes, the Mode Controller will hold the system
in reset until VLLDBGACK is asserted.
The VLLDBGREQ bit clears automatically due to the POR reset
generated as part of the VLLSx recovery.

6

VLLSx Debug Acknowledge
(VLLDBGACK)

N

Set to release a system being held in reset following a VLLSx recovery
This bit is used by the debugger to release the system reset when it is
being held on VLLSx mode exit. The debugger re-initializes all debug
IP and then assert this control bit to allow the Mode Controller to
release the system from reset and allow CPU operation to begin.
The VLLDBGACK bit is cleared by the debugger or can be left set
because it clears automatically due to the POR reset generated as part
of the next VLLSx recovery.

7

LLS, VLLSx Status Acknowledge

N

Set this bit to acknowledge the DAP LLS and VLLS Status bits have
been read. This acknowledge automatically clears the status bits.
This bit is used by the debugger to clear the sticky LLS and VLLSx
mode entry status bits. This bit is asserted and cleared by the
debugger.

8–
31

Reserved for future use

N

1. Command available in secure mode

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Chapter 9 Debug

9.3.2 MDM-AP Status Register
Table 9-4. MDM-AP Status register assignments
Bit
0

Name
Flash Mass Erase Acknowledge

Description
The Flash Mass Erase Acknowledge bit is cleared after any system reset.
The bit is also cleared at launch of a mass erase command due to write of
Flash Mass Erase in Progress bit in MDM AP Control Register. The Flash
Mass Erase Acknowledge is set after Flash control logic has started the
mass erase operation.
When mass erase is disabled (via MEEN and SEC settings), an erase
request due to seting of Flash Mass Erase in Progress bit is not
acknowledged.

1

Flash Ready

Indicate Flash has been initialized and debugger can be configured even if
system is continuing to be held in reset via the debugger.

2

System Security

Indicates the security state. When secure, the debugger does not have
access to the system bus or any memory mapped peripherals. This bit
indicates when the part is locked and no system bus access is possible.

3

System Reset

Indicates the system reset state.
0 System is in reset
1 System is not in reset

4

Reserved

5

Mass Erase Enable

Indicates if the MCU can be mass erased or not
0 Mass erase is disabled
1 Mass erase is enabled

6

Backdoor Access Key Enable

Indicates if the MCU has the backdoor access key enabled.
0 Disabled
1 Enabled

7

LP Enabled

Decode of SMC_PMCTRL[STOPM] field to indicate that VLPS, LLS, or
VLLSx are the selected power mode the next time the ARM Core enters
Deep Sleep.
0 Low Power Stop Mode is not enabled
1 Low Power Stop Mode is enabled
Usage intended for debug operation in which Run to VLPS is attempted.
Per debug definition, the system actually enters the Stop state. A
debugger should interpret deep sleep indication (with SLEEPDEEP and
SLEEPING asserted), in conjuntion with this bit asserted as the debuggerVLPS status indication.

8

Very Low Power Mode

Indicates current power mode is VLPx. This bit is not ‘sticky’ and should
always represent whether VLPx is enabled or not.
This bit is used to throttle SWD_CLK frequency up/down.
Table continues on the next page...

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Debug Resets

Table 9-4. MDM-AP Status register assignments (continued)
Bit
9

Name
LLS Mode Exit

Description
This bit indicates an exit from LLS mode has occurred. The debugger will
lose communication while the system is in LLS (including access to this
register). Once communication is reestablished, this bit indicates that the
system had been in LLS. Since the debug modules held their state during
LLS, they do not need to be reconfigured.
This bit is set during the LLS recovery sequence. The LLS Mode Exit bit is
held until the debugger has had a chance to recognize that LLS was exited
and is cleared by a write of 1 to the LLS, VLLSx Status Acknowledge bit in
MDM AP Control register.

10

VLLSx Modes Exit

This bit indicates an exit from VLLSx mode has occurred. The debugger
will lose communication while the system is in VLLSx (including access to
this register). Once communication is reestablished, this bit indicates that
the system had been in VLLSx. Since the debug modules lose their state
during VLLSx modes, they need to be reconfigured.
This bit is set during the VLLSx recovery sequence. The VLLSx Mode Exit
bit is held until the debugger has had a chance to recognize that a VLLS
mode was exited and is cleared by a write of 1 to the LLS, VLLSx Status
Acknowledge bit in MDM AP Control register.

11 – 15

Reserved for future use

Always read 0.

16

Core Halted

Indicates the Core has entered debug halt mode

17

Core SLEEPDEEP

Indicates the Core has entered a low power mode

18

Core SLEEPING

SLEEPING==1 and SLEEPDEEP==0 indicates wait or VLPW mode.
SLEEPING==1 and SLEEPDEEP==1 indicates stop or VLPS mode.

19 – 31

Reserved for future use

Always read 0.

9.4 Debug Resets
The debug system receives the following sources of reset:
• Debug reset (CDBGRSTREQ bit within the DP CTRL/STAT register) that allows
the debugger to reset the debug logic.
• System POR reset
Conversely the debug system is capable of generating system reset using the following
mechanism:
• A system reset in the DAP control register which allows the debugger to hold the
system in reset.
• SYSRESETREQ bit in the NVIC application interrupt and reset control register
• A system reset in the DAP control register which allows the debugger to hold the
Core in reset.

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Chapter 9 Debug

9.5 Micro Trace Buffer (MTB)
The Micro Trace Buffer (MTB) provides a simple execution trace capability for the
Cortex-M0+ processor. When enabled, the MTB records changes in program flow
reported by the Cortex-M0+ processor, via the execution trace interface, into a
configurable region of the SRAM. Subsequently an off-chip debugger may extract the
trace information, which would allow reconstruction of an instruction flow trace. The
MTB does not include any form of load/store data trace capability or tracing of any other
information.
In addition to providing the trace capability, the MTB also operates as a simple AHB-Lite
SRAM controller. The system bus masters, including the processor, have read/write
access to all of the SRAM via the AHB-Lite interface, allowing the memory to also be
used to store program and data information. The MTB simultaneously stores the trace
information into an attached SRAM and allows bus masters to access the memory. The
MTB ensures that trace information write accesses to the SRAM take priority over
accesses from the AHB-Lite interface.
The MTB includes trace control registers for configuring and triggering the MTB
functions. The MTB also supports triggering via TSTART and TSTOP control functions
in the MTB DWT module.

9.6 Debug in Low Power Modes
In low power modes in which the debug modules are kept static or powered off, the
debugger cannot gather any debug data for the duration of the low power mode. In the
case that the debugger is held static, the debug port returns to full functionality as soon as
the low power mode exits and the system returns to a state with active debug. In the case
that the debugger logic is powered off, the debugger is reset on recovery and must be
reconfigured once the low power mode is exited.

9.7 Debug & Security
When flash security is enabled, the debug port capabilities are limited in order to prevent
exploitation of secure data. In the secure state the debugger still has access to the status
register and can determine the current security state of the device. In the case of a secure
device, the debugger only has the capability of performing a mass erase operation.
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Debug & Security

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Chapter 10
Signal Multiplexing and Signal Descriptions
10.1 Introduction
To optimize functionality in small packages, pins have several functions available via
signal multiplexing. This chapter illustrates which of this device's signals are multiplexed
on which external pin.
The Port Control block controls which signal is present on the external pin. Reference
that chapter to find which register controls the operation of a specific pin.

10.2 Signal Multiplexing Integration
This section summarizes how the module is integrated into the device. For a
comprehensive description of the module itself, see the module’s dedicated chapter.
Peripheral bus
controller 1
Register
access
Transfers

Transfers

External Pins

Module

Signal Multiplexing/
Port Control

Module

Module

Figure 10-1. Signal multiplexing integration
Table 10-1. Reference links to related information
Topic

Related module

Reference

Full description

Port control

Port control

System memory map

System memory map
Table continues on the next page...

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Signal Multiplexing Integration

Table 10-1. Reference links to related information (continued)
Topic

Related module

Reference

Clocking

Clock Distribution

Register access

Peripheral bus
controller

Peripheral bridge

10.2.1 Port control and interrupt module features
• 32-pin ports
NOTE
Not all pins are available on the device. See the following
section for details.
• Port A and Port D is each assigned one interrupt. For DMA requests, Port A and Port
D each have a dedicated input to the DMA MUX.
The reset state and read/write characteristics of the bit fields within the PORTx_PCRn
registers is summarized in the table below.
Table 10-2. Port control register configuration summary
This field
of
PORTx_PC
Rn

Generally
resets to

Except for

Resets to

Configurability

PS

1

PTA0

0

Fixed - All are read only

PE

0

PTA0 and PTA2

1

Yes - All GPIO are
configurable

DSE

0

No exceptions - all DSE are cleared on reset.

—

4 pins are configurable for
High Drive (PTB0 , PTB1,
PTD6 , PTD7). All are
others are fixed for Normal
Drive and the associated
DSE bit is read only.

SRE

1

PTA3, PTA14, PTA15, PTA16, PTA17, PTB10,
PTB11, PTB16, PTB17, PTC3, PTC4, PTC5, PTC6,
PTC7, PTD4, PTD5, PTD6, PTD7

0

Fixed - All are read only

MUX

000

PTA0, PTA3 and PTA4

111

Yes - All GPIO are
configurable

PFE

0

No exceptions - all PFE are cleared on reset.1

—

The GPIO shared with
NMI_b pin is configurable.
All other GPIO is fixed and
read only.

IRQC

000

No exceptions - all are cleared on reset.

—

Only implemented for
ports that support interrupt
and DMA functionality.

Table continues on the next page...

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Chapter 10 Signal Multiplexing and Signal Descriptions

Table 10-2. Port control register configuration summary (continued)
This field
of
PORTx_PC
Rn
ISF

Generally
resets to

0

Except for

Resets to

No exceptions - all are cleared on reset.

—

Configurability

Only implemented for
ports that support interrupt
and DMA functionality.

1. The RESET pin has the passive analog filter fixed enabled when functioning as the RESET pin (FOPT[RESET_PIN_CFG]
= 1) and fixed disabled when configured for other shared functions.

10.2.2 Clock gating
The clock to the port control module can be gated on and off using the SCGC5[PORTx]
bits in the SIM module. These bits are cleared after any reset, which disables the clock to
the corresponding module to conserve power. Prior to initializing the corresponding
module, set SCGC5[PORTx] in the SIM module to enable the clock. Before turning off
the clock, make sure to disable the module. For more details, refer to the clock
distribution chapter.

10.2.3 Signal multiplexing constraints
1. A given peripheral function must be assigned to a maximum of one package pin. Do
not program the same function to more than one pin.
2. To ensure the best signal timing for a given peripheral's interface, choose the pins in
closest proximity to each other.

10.3 Pinout
10.3.1 KL25 Signal Multiplexing and Pin Assignments
The following table shows the signals available on each pin and the locations of these
pins on the devices supported by this document. The Port Control Module is responsible
for selecting which ALT functionality is available on each pin.
80
64
LQFP LQFP

48
QFN

32
QFN

Pin Name

Default

ALT0

ALT1

1

1

—

1

PTE0

DISABLED

PTE0

2

2

—

—

PTE1

DISABLED

PTE1

ALT2

SPI1_MOSI

ALT3

ALT4

ALT5

ALT6

UART1_TX

RTC_CLKOUT CMP0_OUT

I2C1_SDA

UART1_RX

SPI1_MISO

I2C1_SCL

ALT7

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Pinout
80
64
LQFP LQFP

48
QFN

32
QFN

Pin Name

Default

ALT0

ALT1

ALT2

3

—

—

—

PTE2

DISABLED

PTE2

SPI1_SCK

4

—

—

—

PTE3

DISABLED

PTE3

SPI1_MISO

5

—

—

—

PTE4

DISABLED

PTE4

SPI1_PCS0

6

—

—

—

PTE5

DISABLED

PTE5

7

3

1

—

VDD

VDD

ALT3

ALT4

ALT5

ALT6

ALT7

SPI1_MOSI

VDD

8

4

2

2

VSS

VSS

VSS

9

5

3

3

USB0_DP

USB0_DP

USB0_DP

10

6

4

4

USB0_DM

USB0_DM

USB0_DM

11

7

5

5

VOUT33

VOUT33

VOUT33

12

8

6

6

VREGIN

VREGIN

VREGIN

13

9

7

—

PTE20

ADC0_DP0/
ADC0_SE0

ADC0_DP0/
ADC0_SE0

PTE20

TPM1_CH0

UART0_TX

14

10

8

—

PTE21

ADC0_DM0/
ADC0_SE4a

ADC0_DM0/
ADC0_SE4a

PTE21

TPM1_CH1

UART0_RX

15

11

—

—

PTE22

ADC0_DP3/
ADC0_SE3

ADC0_DP3/
ADC0_SE3

PTE22

TPM2_CH0

UART2_TX

16

12

—

—

PTE23

ADC0_DM3/
ADC0_SE7a

ADC0_DM3/
ADC0_SE7a

PTE23

TPM2_CH1

UART2_RX

17

13

9

7

VDDA

VDDA

VDDA

18

14

10

—

VREFH

VREFH

VREFH

19

15

11

—

VREFL

VREFL

VREFL

20

16

12

8

VSSA

VSSA

VSSA

21

17

13

—

PTE29

CMP0_IN5/
ADC0_SE4b

CMP0_IN5/
ADC0_SE4b

PTE29

TPM0_CH2

TPM_CLKIN0

22

18

14

9

PTE30

DAC0_OUT/
ADC0_SE23/
CMP0_IN4

DAC0_OUT/
ADC0_SE23/
CMP0_IN4

PTE30

TPM0_CH3

TPM_CLKIN1

23

19

—

—

PTE31

DISABLED

PTE31

TPM0_CH4

24

20

15

—

PTE24

DISABLED

PTE24

TPM0_CH0

I2C0_SCL

25

21

16

—

PTE25

DISABLED

PTE25

TPM0_CH1

I2C0_SDA

26

22

17

10

PTA0

SWD_CLK

TSI0_CH1

PTA0

27

23

18

11

PTA1

DISABLED

TSI0_CH2

PTA1

UART0_RX

TPM2_CH0

TPM0_CH5

SWD_CLK

28

24

19

12

PTA2

DISABLED

TSI0_CH3

PTA2

UART0_TX

TPM2_CH1

29

25

20

13

PTA3

SWD_DIO

TSI0_CH4

PTA3

I2C1_SCL

TPM0_CH0

SWD_DIO

30

26

21

14

PTA4

NMI_b

TSI0_CH5

PTA4

I2C1_SDA

TPM0_CH1

NMI_b

31

27

—

—

PTA5

DISABLED

PTA5

USB_CLKIN

TPM0_CH2

32

28

—

—

PTA12

DISABLED

PTA12

TPM1_CH0

33

29

—

—

PTA13

DISABLED

PTA13

TPM1_CH1

34

—

—

—

PTA14

DISABLED

PTA14

SPI0_PCS0

UART0_TX

35

—

—

—

PTA15

DISABLED

PTA15

SPI0_SCK

UART0_RX

36

—

—

—

PTA16

DISABLED

PTA16

SPI0_MOSI

SPI0_MISO

37

—

—

—

PTA17

DISABLED

PTA17

SPI0_MISO

SPI0_MOSI

38

30

22

15

VDD

VDD

VDD

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Chapter 10 Signal Multiplexing and Signal Descriptions
80
64
LQFP LQFP

48
QFN

32
QFN

Pin Name

Default

ALT0

ALT1

ALT2

ALT3

ALT4

39

31

23

16

VSS

VSS

VSS

40

32

24

17

PTA18

EXTAL0

EXTAL0

PTA18

UART1_RX

TPM_CLKIN0

41

33

25

18

PTA19

XTAL0

XTAL0

PTA19

UART1_TX

TPM_CLKIN1

42

34

26

19

RESET_b

RESET_b

43

35

27

20

PTB0/
LLWU_P5

ADC0_SE8/
TSI0_CH0

ADC0_SE8/
TSI0_CH0

PTB0/
LLWU_P5

I2C0_SCL

TPM1_CH0

44

36

28

21

PTB1

ADC0_SE9/
TSI0_CH6

ADC0_SE9/
TSI0_CH6

PTB1

I2C0_SDA

TPM1_CH1

45

37

29

—

PTB2

ADC0_SE12/
TSI0_CH7

ADC0_SE12/
TSI0_CH7

PTB2

I2C0_SCL

TPM2_CH0

46

38

30

—

PTB3

ADC0_SE13/
TSI0_CH8

ADC0_SE13/
TSI0_CH8

PTB3

I2C0_SDA

TPM2_CH1

47

—

—

—

PTB8

DISABLED

PTB8

48

—

—

—

PTB9

DISABLED

PTB9

49

—

—

—

PTB10

DISABLED

PTB10

ALT5

ALT6

ALT7

LPTMR0_
ALT1

PTA20

EXTRG_IN
SPI1_PCS0

50

—

—

—

PTB11

DISABLED

PTB11

SPI1_SCK

51

39

31

—

PTB16

TSI0_CH9

TSI0_CH9

PTB16

SPI1_MOSI

UART0_RX

TPM_CLKIN0

SPI1_MISO

52

40

32

—

PTB17

TSI0_CH10

TSI0_CH10

PTB17

SPI1_MISO

UART0_TX

TPM_CLKIN1

SPI1_MOSI

53

41

—

—

PTB18

TSI0_CH11

TSI0_CH11

PTB18

TPM2_CH0

54

42

—

—

PTB19

TSI0_CH12

TSI0_CH12

PTB19

TPM2_CH1

55

43

33

—

PTC0

ADC0_SE14/
TSI0_CH13

ADC0_SE14/
TSI0_CH13

PTC0

EXTRG_IN

56

44

34

22

PTC1/
LLWU_P6/
RTC_CLKIN

ADC0_SE15/
TSI0_CH14

ADC0_SE15/
TSI0_CH14

PTC1/
LLWU_P6/
RTC_CLKIN

I2C1_SCL

TPM0_CH0

57

45

35

23

PTC2

ADC0_SE11/
TSI0_CH15

ADC0_SE11/
TSI0_CH15

PTC2

I2C1_SDA

TPM0_CH1

58

46

36

24

PTC3/
LLWU_P7

DISABLED

59

47

—

—

VSS

VSS

VSS

60

48

—

—

VDD

VDD

VDD

61

49

37

25

PTC4/
LLWU_P8

DISABLED

PTC4/
LLWU_P8

62

50

38

26

PTC5/
LLWU_P9

DISABLED

63

51

39

27

PTC6/
LLWU_P10

CMP0_IN0

64

52

40

28

PTC7

65

53

—

—

PTC8

PTC3/
LLWU_P7

CMP0_OUT

UART1_RX

TPM0_CH2

SPI0_PCS0

UART1_TX

TPM0_CH3

PTC5/
LLWU_P9

SPI0_SCK

LPTMR0_
ALT2

CMP0_IN0

PTC6/
LLWU_P10

SPI0_MOSI

EXTRG_IN

CMP0_IN1

CMP0_IN1

PTC7

SPI0_MISO

CMP0_IN2

CMP0_IN2

PTC8

I2C0_SCL

TPM0_CH4

CMP0_IN3

TPM0_CH5

CLKOUT

CMP0_OUT
SPI0_MISO
SPI0_MOSI

66

54

—

—

PTC9

CMP0_IN3

PTC9

I2C0_SDA

67

55

—

—

PTC10

DISABLED

PTC10

I2C1_SCL

68

56

—

—

PTC11

DISABLED

PTC11

I2C1_SDA

69

—

—

—

PTC12

DISABLED

PTC12

TPM_CLKIN0

70

—

—

—

PTC13

DISABLED

PTC13

TPM_CLKIN1

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Pinout
80
64
LQFP LQFP

48
QFN

32
QFN

Pin Name

Default

ALT0

ALT1

ALT2

ALT3

ALT4

71

—

—

—

PTC16

DISABLED

PTC16

72

—

—

—

PTC17

DISABLED

PTC17

73

57

41

—

PTD0

DISABLED

PTD0

SPI0_PCS0

TPM0_CH0

74

58

42

—

PTD1

ADC0_SE5b

PTD1

SPI0_SCK

TPM0_CH1

75

59

43

—

PTD2

DISABLED

PTD2

SPI0_MOSI

ADC0_SE5b

UART2_RX

ALT5

TPM0_CH2

SPI0_MISO
SPI0_MOSI

76

60

44

—

PTD3

DISABLED

PTD3

SPI0_MISO

UART2_TX

TPM0_CH3

77

61

45

29

PTD4/
LLWU_P14

DISABLED

PTD4/
LLWU_P14

SPI1_PCS0

UART2_RX

TPM0_CH4

78

62

46

30

PTD5

ADC0_SE6b

ADC0_SE6b

PTD5

SPI1_SCK

UART2_TX

TPM0_CH5

79

63

47

31

PTD6/
LLWU_P15

ADC0_SE7b

ADC0_SE7b

PTD6/
LLWU_P15

SPI1_MOSI

UART0_RX

SPI1_MISO

80

64

48

32

PTD7

DISABLED

PTD7

SPI1_MISO

UART0_TX

SPI1_MOSI

ALT6

ALT7

10.3.2 KL25 Pinouts
The below figures show the pinout diagrams for the devices supported by this document.
Many signals may be multiplexed onto a single pin. To determine what signals can be
used on which pin, see the previous section.

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PTD7

PTD6/LLWU_P15

PTD5

PTD4/LLWU_P14

PTD3

PTD2

PTD1

PTD0

PTC17

PTC16

PTC13

PTC12

PTC11

PTC10

PTC9

PTC8

PTC7

PTC6/LLWU_P10

PTC5/LLWU_P9

PTC4/LLWU_P8

80

79

78

77

76

75

74

73

72

71

70

69

68

67

66

65

64

63

62

61

Chapter 10 Signal Multiplexing and Signal Descriptions

VOUT33

11

50

PTB11

VREGIN

12

49

PTB10

PTE20

13

48

PTB9

PTE21

14

47

PTB8

PTE22

15

46

PTB3

PTE23

16

45

PTB2

VDDA

17

44

PTB1

VREFH

18

43

PTB0/LLWU_P5

VREFL

19

42

RESET_b

VSSA

20

41

PTA19

40

PTB16

PTA18

51

39

10

VSS

USB0_DM

38

PTB17

VDD

52

37

9

PTA17

USB0_DP

36

PTB18

PTA16

53

35

8

PTA15

VSS

34

PTB19

PTA14

54

33

7

PTA13

VDD

PTA12

PTC0

32

55

31

6

PTA5

PTE5

30

PTC1/LLWU_P6/RTC_CLKIN

PTA4

56

29

5

PTA3

PTE4

28

PTC2

PTA2

57

27

4

PTA1

PTE3

26

PTC3/LLWU_P7

PTA0

58

25

3

PTE25

PTE2

24

VSS

PTE24

59

23

2

PTE31

PTE1

22

VDD

PTE30

60

21

1

PTE29

PTE0

Figure 10-2. KL25 80-pin LQFP pinout diagram

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165

PTD7

PTD6/LLWU_P15

PTD5

PTD4/LLWU_P14

PTD3

PTD2

PTD1

PTD0

PTC11

PTC10

PTC9

PTC8

PTC7

PTC6/LLWU_P10

PTC5/LLWU_P9

PTC4/LLWU_P8

64

63

62

61

60

59

58

57

56

55

54

53

52

51

50

49

Pinout

PTB18

PTE20

9

40

PTB17

PTE21

10

39

PTB16

PTE22

11

38

PTB3

PTE23

12

37

PTB2

VDDA

13

36

PTB1

VREFH

14

35

PTB0/LLWU_P5

VREFL

15

34

RESET_b

VSSA

16

33

PTA19

PTA18

32

41

31

8

VSS

VREGIN

30

PTB19

VDD

42

29

7

PTA13

VOUT33

28

PTC0

PTA12

43

27

6

PTA5

USB0_DM

26

PTC1/LLWU_P6/RTC_CLKIN

PTA4

44

25

5

PTA3

USB0_DP

24

PTC2

PTA2

45

23

4

PTA1

VSS

22

PTC3/LLWU_P7

PTA0

46

21

3

PTE25

VDD

20

VSS

PTE24

47

19

2

PTE31

PTE1

18

VDD

PTE30

48

17

1

PTE29

PTE0

Figure 10-3. KL25 64-pin LQFP pinout diagram

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PTD7

PTD6/LLWU_P15

PTD5

PTD4/LLWU_P14

PTD3

PTD2

PTD1

PTD0

PTC7

PTC6/LLWU_P10

PTC5/LLWU_P9

PTC4/LLWU_P8

48

47

46

45

44

43

42

41

40

39

38

37

Chapter 10 Signal Multiplexing and Signal Descriptions

PTE20

7

30

PTB3

PTE21

8

29

PTB2

VDDA

9

28

PTB1

VREFH

10

27

PTB0/LLWU_P5

VREFL

11

26

RESET_b

VSSA

12

25

PTA19

24

PTB16

PTA18

31

23

6

VSS

VREGIN

22

PTB17

VDD

32

21

5

PTA4

VOUT33

20

PTC0

PTA3

33

19

4

PTA2

USB0_DM

18

PTC1/LLWU_P6/RTC_CLKIN

PTA1

34

17

3

PTA0

USB0_DP

16

PTC2

PTE25

35

15

2

PTE24

VSS

14

PTC3/LLWU_P7

PTE30

36

13

1

PTE29

VDD

Figure 10-4. KL25 48-pin QFN pinout diagram

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167

PTD7

PTD6/LLWU_P15

PTD5

PTD4/LLWU_P14

PTC7

PTC6/LLWU_P10

PTC5/LLWU_P9

PTC4/LLWU_P8

32

31

30

29

28

27

26

25

Module Signal Description Tables

21

PTB1

VOUT33

5

20

PTB0/LLWU_P5

VREGIN

6

19

RESET_b

VDDA

7

18

PTA19

VSSA

8

17

PTA18

PTA0

PTE30

16

4

VSS

USB0_DM

15

PTC1/LLWU_P6/RTC_CLKIN

VDD

22

14

3

PTA4

USB0_DP

13

PTC2

PTA3

23

12

2

PTA2

VSS

11

PTC3/LLWU_P7

PTA1

24

10

1

9

PTE0

Figure 10-5. KL25 32-pin QFN pinout diagram

10.4 Module Signal Description Tables
The following sections correlate the chip-level signal name with the signal name used in
the module's chapter. They also briefly describe the signal function and direction.

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Chapter 10 Signal Multiplexing and Signal Descriptions

10.4.1 Core Modules
Table 10-3. SWD Signal Descriptions
Chip signal name

Module signal
name

Description

I/O

SWD_DIO

SWD_DIO

Serial wire debug data input/output. The SWD_DIO pin is used by
an external debug tool for communication and device control. This
pin is pulled up internally.

Input /
Output

SWD_CLK

SWD_CLK

Serial Wire Clock. This pin is the clock for debug logic when in the
Serial Wire Debug mode. This pin is pulled down internally.

Input

10.4.2 System Modules
Table 10-4. System Signal Descriptions
Chip signal name

Module signal
name

NMI

—

Description
Non-maskable interrupt

I/O
I

NOTE: Driving the NMI signal low forces a non-maskable
interrupt, if the NMI function is selected on the
corresponding pin.
RESET

—

Reset bi-directional signal

I/O

VDD

—

MCU power

I

VSS

—

MCU ground

I

10.4.3 Clock Modules
Table 10-5. OSC Signal Descriptions
Chip signal name

Module signal
name

EXTAL0

EXTAL

XTAL0

XTAL

Description

I/O

External clock/Oscillator input

I

Oscillator output

O

10.4.4 Memories and Memory Interfaces

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Module Signal Description Tables

10.4.5 Analog
Table 10-6. ADC 0 Signal Descriptions
Chip signal name

Module signal
name

Description

I/O

ADC0_DPn

DADP3–DADP0

Differential Analog Channel Inputs

I

ADC0_DMn

DADM3–DADM0

Differential Analog Channel Inputs

I

ADC0_SEn

ADn

Single-Ended Analog Channel Inputs

I

VREFH

VREFSH

Voltage Reference Select High

I

VREFL

VREFSL

Voltage Reference Select Low

I

VDDA

VDDA

Analog Power Supply

I

VSSA

VSSA

Analog Ground

I

Table 10-7. CMP 0 Signal Descriptions
Chip signal name

Module signal
name

Description

I/O

CMP0_IN[5:0]

IN[5:0]

Analog voltage inputs

I

CMP0_OUT

CMPO

Comparator output

O

Table 10-8. DAC 0 Signal Descriptions
Chip signal name

Module signal
name

DAC0_OUT

—

Description

I/O

DAC output

O

10.4.6 Timer Modules
Table 10-9. TPM 0 Signal Descriptions
Chip signal name

Module signal
name

TPM_CLKIN[2:0]

EXTCLK

TPM0_CH[5:0]

CHn

Description

I/O

External clock. FTM external clock can be selected to drive the
FTM counter.
FTM channel (n), where n can be 7-0

I
I/O

Table 10-10. TPM 1 Signal Descriptions
Chip signal name

Module signal
name

Description

I/O

TPM_CLKIN[2:0]

TPM_EXTCLK

External clock. TPM external clock can be selected to increment the
TPM counter on every rising edge synchronized to the counter
clock.

I

Table continues on the next page...

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Chapter 10 Signal Multiplexing and Signal Descriptions

Table 10-10. TPM 1 Signal Descriptions (continued)
Chip signal name

Module signal
name

TPM1_CH[1:0]

TPM_CHn

Description

I/O

TPM channel (n = 5 to 0)

I/O

Table 10-11. TPM 2 Signal Descriptions
Chip signal name

Module signal
name

Description

TPM_CLKIN[2:0]

TPM_EXTCLK

External clock. TPM external clock can be selected to increment the
TPM counter on every rising edge synchronized to the counter
clock.

TPM2_CH[1:0]

TPM_CHn

TPM channel (n = 5 to 0)

I/O
I

I/O

Table 10-12. LPTMR 0 Signal Descriptions
Chip signal name

Module signal
name

Description

LPTMR0_ALT[2:1]

LPTMR_ALTn

Pulse Counter Input pin

I/O
I

Table 10-13. RTC Signal Descriptions
Chip signal name

Module signal
name

Description

I/O

RTC_CLKOUT1

RTC_CLKOUT

1 Hz square-wave output

O

1. RTC_CLKOUT can also be driven with OSCERCLK via SIM control bit SIM_SOPT[RCTCLKOUTSEL]

10.4.7 Communication Interfaces
Table 10-14. USB FS OTG Signal Descriptions
Chip signal name

Module signal
name

Description

I/O

USB0_DM
USB0_DP

usb_dm

USB D- analog data signal on the USB bus.

I/O

usb_dp

USB D+ analog data signal on the USB bus.

I/O

USB_CLKIN

—

Alternate USB clock input

I

Table 10-15. USB VREG Signal Descriptions
Chip signal name

Module signal
name

VOUT33

reg33_out

VREGIN

reg33_in

Description

I/O

Regulator output voltage

O

Unregulated power supply

I

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Module Signal Description Tables

Table 10-16. SPI0 Signal Descriptions
Chip signal name

Module signal
name

Description

I/O

SPI0_MISO

MISO

Master Data In, Slave Data Out

I/O

SPI0_MOSI

MOSI

Master Data Out, Slave Data In

I/O

SPI0_SCLK

SPSCK

SPI Serial Clock

I/O

SPI0_PCS0

SS

Slave Select

I/O

Table 10-17. SPI1 Signal Descriptions
Chip signal name

Module signal
name

Description

I/O

SPI1_MISO

MISO

Master Data In, Slave Data Out

I/O

SPI1_MOSI

MOSI

Master Data Out, Slave Data In

I/O

SPI1_SCLK

SPSCK

SPI Serial Clock

I/O

SPI1_PCS0

SS

Slave Select

I/O

Table 10-18. I2C 0 Signal Descriptions
Chip signal name

Module signal
name

I2C0_SCL

SCL

I2C0_SDA

SDA

Description

I/O

Bidirectional serial clock line of the I2C system.
Bidirectional serial data line of the

I2C

I/O

system.

I/O

Table 10-19. I2C 1 Signal Descriptions
Chip signal name

Module signal
name

Description

I/O

I2C1_SCL

SCL

Bidirectional serial clock line of the I2C system.

I/O

I2C1_SDA

SDA

Bidirectional serial data line of the I2C system.

I/O

Table 10-20. UART 0 Signal Descriptions
Chip signal name

Module signal
name

Description

I/O

UART0_TX

TXD

Transmit data

O

UART0_RX

RXD

Receive data

I

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Chapter 10 Signal Multiplexing and Signal Descriptions

Table 10-21. UART 1 Signal Descriptions
Chip signal name

Module signal
name

Description

I/O

UART1_TX

TXD

Transmit data

O

UART1_RX

RXD

Receive data

I

Table 10-22. UART 2 Signal Descriptions
Chip signal name

Module signal
name

Description

I/O

UART2_TX

TXD

Transmit data

O

UART2_RX

RXD

Receive data

I

10.4.8 Human-Machine Interfaces (HMI)
Table 10-23. GPIO Signal Descriptions
Chip signal name

Module signal
name

Description

I/O

PTA[31:0]1

PORTA31–PORTA0 General-purpose input/output

I/O

PTB[31:0]1

PORTB31–PORTB0 General-purpose input/output

I/O

PTC[31:0]1

PORTC31–PORTC0 General-purpose input/output

I/O

PTD[31:0]1

PORTD31–PORTD0 General-purpose input/output

I/O

PTE[31:0]1

PORTE31–PORTE0 General-purpose input/output

I/O

1. The available GPIO pins depends on the specific package. See the signal multiplexing section for which exact GPIO
signals are available.

Table 10-24. TSI Signal Descriptions
Chip signal name

Module signal
name

TSI0_CH[15:0]

TSI[15:0]

Description

I/O

TSI capacitive pins. Switches driver that connects directly to the
electrode pins TSI[15:0] can operate as GPIO pins.

I/O

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Module Signal Description Tables

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Chapter 11
Port control and interrupts (PORT)
11.1 Introduction
NOTE
For the chip-specific implementation details of this module's
instances see the chip configuration information.

11.2 Overview
The port control and interrupt (PORT) module provides support for port control, and
external interrupt functions. Most functions can be configured independently for each pin
in the 32-bit port and affect the pin regardless of its pin muxing state.
There is one instance of the PORT module for each port. Not all pins within each port are
implemented on a specific device.

11.2.1 Features
The PORT module has the following features:
• Pin interrupt on selected pins
• Interrupt flag and enable registers for each pin
• Support for edge sensitive (rising, falling, both) or level sensitive (low, high)
configured per pin
• Support for interrupt or DMA request configured per pin
• Asynchronous wakeup in Low-Power modes
• Pin interrupt is functional in all digital Pin Muxing modes
• Port control

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External signal description

• Individual pull control fields with pullup, pulldown, and pull-disablesupport on
selected pins
• Individual drive strength field supporting high and low drive strength on selected
pins
• Individual slew rate field supporting fast and slow slew rates on selected pins
• Individual input passive filter field supporting enable and disable of the
individual input passive filter on selected pins
• Individual mux control field supporting analog or pin disabled, GPIO, and up to
six chip-specific digital functions
• Pad configuration fields are functional in all digital Pin Muxing modes

11.2.2 Modes of operation
11.2.2.1 Run mode
In Run mode, the PORT operates normally.

11.2.2.2 Wait mode
In Wait mode, PORT continues to operate normally and may be configured to exit the
Low-Power mode if an enabled interrupt is detected. DMA requests are still generated
during the Wait mode, but do not cause an exit from the Low-Power mode.

11.2.2.3 Stop mode
In Stop mode, the PORT can be configured to exit the Low-Power mode via an
asynchronous wakeup signal if an enabled interrupt is detected.

11.2.2.4 Debug mode
In Debug mode, PORT operates normally.

11.3 External signal description
The following table describes the PORT external signal.
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Chapter 11 Port control and interrupts (PORT)

Table 11-1. Signal properties
Name

Function

I/O

Reset

Pull

PORTx[31:0]

External interrupt

I/O

0

-

NOTE
Not all pins within each port are implemented on each device.

11.4 Detailed signal description
The following table contains the detailed signal description for the PORT interface.
Table 11-2. PORT interface—detailed signal description
Signal
PORTx[31:0]

I/O
I/O

Description
External interrupt.
State meaning

Asserted—pin is logic one.
Negated—pin is logic zero.

Timing

Assertion—may occur at any time and can assert
asynchronously to the system clock.
Negation—may occur at any time and can assert
asynchronously to the system clock.

11.5 Memory map and register definition
Any read or write access to the PORT memory space that is outside the valid memory
map results in a bus error. All register accesses complete with zero wait states.
PORT memory map
Absolute
address
(hex)

Register name

Width
Access
(in bits)

Reset value

Section/
page

4004_9000

Pin Control Register n (PORTA_PCR0)

32

R/W

See section

11.5.1/183

4004_9004

Pin Control Register n (PORTA_PCR1)

32

R/W

See section

11.5.1/183

4004_9008

Pin Control Register n (PORTA_PCR2)

32

R/W

See section

11.5.1/183

4004_900C

Pin Control Register n (PORTA_PCR3)

32

R/W

See section

11.5.1/183

4004_9010

Pin Control Register n (PORTA_PCR4)

32

R/W

See section

11.5.1/183

4004_9014

Pin Control Register n (PORTA_PCR5)

32

R/W

See section

11.5.1/183

4004_9018

Pin Control Register n (PORTA_PCR6)

32

R/W

See section

11.5.1/183

4004_901C

Pin Control Register n (PORTA_PCR7)

32

R/W

See section

11.5.1/183

Table continues on the next page...

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Memory map and register definition

PORT memory map (continued)
Absolute
address
(hex)

Register name

Width
Access
(in bits)

Reset value

Section/
page

4004_9020

Pin Control Register n (PORTA_PCR8)

32

R/W

See section

11.5.1/183

4004_9024

Pin Control Register n (PORTA_PCR9)

32

R/W

See section

11.5.1/183

4004_9028

Pin Control Register n (PORTA_PCR10)

32

R/W

See section

11.5.1/183

4004_902C

Pin Control Register n (PORTA_PCR11)

32

R/W

See section

11.5.1/183

4004_9030

Pin Control Register n (PORTA_PCR12)

32

R/W

See section

11.5.1/183

4004_9034

Pin Control Register n (PORTA_PCR13)

32

R/W

See section

11.5.1/183

4004_9038

Pin Control Register n (PORTA_PCR14)

32

R/W

See section

11.5.1/183

4004_903C

Pin Control Register n (PORTA_PCR15)

32

R/W

See section

11.5.1/183

4004_9040

Pin Control Register n (PORTA_PCR16)

32

R/W

See section

11.5.1/183

4004_9044

Pin Control Register n (PORTA_PCR17)

32

R/W

See section

11.5.1/183

4004_9048

Pin Control Register n (PORTA_PCR18)

32

R/W

See section

11.5.1/183

4004_904C

Pin Control Register n (PORTA_PCR19)

32

R/W

See section

11.5.1/183

4004_9050

Pin Control Register n (PORTA_PCR20)

32

R/W

See section

11.5.1/183

4004_9054

Pin Control Register n (PORTA_PCR21)

32

R/W

See section

11.5.1/183

4004_9058

Pin Control Register n (PORTA_PCR22)

32

R/W

See section

11.5.1/183

4004_905C

Pin Control Register n (PORTA_PCR23)

32

R/W

See section

11.5.1/183

4004_9060

Pin Control Register n (PORTA_PCR24)

32

R/W

See section

11.5.1/183

4004_9064

Pin Control Register n (PORTA_PCR25)

32

R/W

See section

11.5.1/183

4004_9068

Pin Control Register n (PORTA_PCR26)

32

R/W

See section

11.5.1/183

4004_906C

Pin Control Register n (PORTA_PCR27)

32

R/W

See section

11.5.1/183

4004_9070

Pin Control Register n (PORTA_PCR28)

32

R/W

See section

11.5.1/183

4004_9074

Pin Control Register n (PORTA_PCR29)

32

R/W

See section

11.5.1/183

4004_9078

Pin Control Register n (PORTA_PCR30)

32

R/W

See section

11.5.1/183

4004_907C

Pin Control Register n (PORTA_PCR31)

32

R/W

See section

11.5.1/183

4004_9080

Global Pin Control Low Register (PORTA_GPCLR)

32

W
(always 0000_0000h
reads 0)

11.5.2/185

4004_9084

Global Pin Control High Register (PORTA_GPCHR)

32

W
(always 0000_0000h
reads 0)

11.5.3/186

4004_90A0

Interrupt Status Flag Register (PORTA_ISFR)

32

w1c

0000_0000h

11.5.4/186

4004_A000

Pin Control Register n (PORTB_PCR0)

32

R/W

See section

11.5.1/183

4004_A004

Pin Control Register n (PORTB_PCR1)

32

R/W

See section

11.5.1/183

4004_A008

Pin Control Register n (PORTB_PCR2)

32

R/W

See section

11.5.1/183

4004_A00C Pin Control Register n (PORTB_PCR3)

32

R/W

See section

11.5.1/183

4004_A010

Pin Control Register n (PORTB_PCR4)

32

R/W

See section

11.5.1/183

4004_A014

Pin Control Register n (PORTB_PCR5)

32

R/W

See section

11.5.1/183

4004_A018

Pin Control Register n (PORTB_PCR6)

32

R/W

See section

11.5.1/183

4004_A01C Pin Control Register n (PORTB_PCR7)

32

R/W

See section

11.5.1/183

Table continues on the next page...

KL25 Sub-Family Reference Manual, Rev. 3, September 2012
178

Freescale Semiconductor, Inc.

Chapter 11 Port control and interrupts (PORT)

PORT memory map (continued)
Absolute
address
(hex)

Register name

Width
Access
(in bits)

Reset value

Section/
page

4004_A020

Pin Control Register n (PORTB_PCR8)

32

R/W

See section

11.5.1/183

4004_A024

Pin Control Register n (PORTB_PCR9)

32

R/W

See section

11.5.1/183

4004_A028

Pin Control Register n (PORTB_PCR10)

32

R/W

See section

11.5.1/183

4004_A02C Pin Control Register n (PORTB_PCR11)

32

R/W

See section

11.5.1/183

4004_A030

Pin Control Register n (PORTB_PCR12)

32

R/W

See section

11.5.1/183

4004_A034

Pin Control Register n (PORTB_PCR13)

32

R/W

See section

11.5.1/183

4004_A038

Pin Control Register n (PORTB_PCR14)

32

R/W

See section

11.5.1/183

4004_A03C Pin Control Register n (PORTB_PCR15)

32

R/W

See section

11.5.1/183

4004_A040

Pin Control Register n (PORTB_PCR16)

32

R/W

See section

11.5.1/183

4004_A044

Pin Control Register n (PORTB_PCR17)

32

R/W

See section

11.5.1/183

4004_A048

Pin Control Register n (PORTB_PCR18)

32

R/W

See section

11.5.1/183

4004_A04C Pin Control Register n (PORTB_PCR19)

32

R/W

See section

11.5.1/183

4004_A050

Pin Control Register n (PORTB_PCR20)

32

R/W

See section

11.5.1/183

4004_A054

Pin Control Register n (PORTB_PCR21)

32

R/W

See section

11.5.1/183

4004_A058

Pin Control Register n (PORTB_PCR22)

32

R/W

See section

11.5.1/183

4004_A05C Pin Control Register n (PORTB_PCR23)

32

R/W

See section

11.5.1/183

4004_A060

Pin Control Register n (PORTB_PCR24)

32

R/W

See section

11.5.1/183

4004_A064

Pin Control Register n (PORTB_PCR25)

32

R/W

See section

11.5.1/183

4004_A068

Pin Control Register n (PORTB_PCR26)

32

R/W

See section

11.5.1/183

4004_A06C Pin Control Register n (PORTB_PCR27)

32

R/W

See section

11.5.1/183

4004_A070

Pin Control Register n (PORTB_PCR28)

32

R/W

See section

11.5.1/183

4004_A074

Pin Control Register n (PORTB_PCR29)

32

R/W

See section

11.5.1/183

4004_A078

Pin Control Register n (PORTB_PCR30)

32

R/W

See section

11.5.1/183

4004_A07C Pin Control Register n (PORTB_PCR31)

32

R/W

See section

11.5.1/183

4004_A080

Global Pin Control Low Register (PORTB_GPCLR)

32

W
(always 0000_0000h
reads 0)

11.5.2/185

4004_A084

Global Pin Control High Register (PORTB_GPCHR)

32

W
(always 0000_0000h
reads 0)

11.5.3/186

4004_A0A0 Interrupt Status Flag Register (PORTB_ISFR)

32

w1c

0000_0000h

11.5.4/186

4004_B000

Pin Control Register n (PORTC_PCR0)

32

R/W

See section

11.5.1/183

4004_B004

Pin Control Register n (PORTC_PCR1)

32

R/W

See section

11.5.1/183

4004_B008

Pin Control Register n (PORTC_PCR2)

32

R/W

See section

11.5.1/183

4004_B00C Pin Control Register n (PORTC_PCR3)

32

R/W

See section

11.5.1/183

4004_B010

Pin Control Register n (PORTC_PCR4)

32

R/W

See section

11.5.1/183

4004_B014

Pin Control Register n (PORTC_PCR5)

32

R/W

See section

11.5.1/183

4004_B018

Pin Control Register n (PORTC_PCR6)

32

R/W

See section

11.5.1/183

4004_B01C Pin Control Register n (PORTC_PCR7)

32

R/W

See section

11.5.1/183

Table continues on the next page...

KL25 Sub-Family Reference Manual, Rev. 3, September 2012
Freescale Semiconductor, Inc.

179

Memory map and register definition

PORT memory map (continued)
Absolute
address
(hex)

Register name

Width
Access
(in bits)

Reset value

Section/
page

4004_B020

Pin Control Register n (PORTC_PCR8)

32

R/W

See section

11.5.1/183

4004_B024

Pin Control Register n (PORTC_PCR9)

32

R/W

See section

11.5.1/183

4004_B028

Pin Control Register n (PORTC_PCR10)

32

R/W

See section

11.5.1/183

4004_B02C Pin Control Register n (PORTC_PCR11)

32

R/W

See section

11.5.1/183

4004_B030

Pin Control Register n (PORTC_PCR12)

32

R/W

See section

11.5.1/183

4004_B034

Pin Control Register n (PORTC_PCR13)

32

R/W

See section

11.5.1/183

4004_B038

Pin Control Register n (PORTC_PCR14)

32

R/W

See section

11.5.1/183

4004_B03C Pin Control Register n (PORTC_PCR15)

32

R/W

See section

11.5.1/183

4004_B040

Pin Control Register n (PORTC_PCR16)

32

R/W

See section

11.5.1/183

4004_B044

Pin Control Register n (PORTC_PCR17)

32

R/W

See section

11.5.1/183

4004_B048

Pin Control Register n (PORTC_PCR18)

32

R/W

See section

11.5.1/183

4004_B04C Pin Control Register n (PORTC_PCR19)

32

R/W

See section

11.5.1/183

4004_B050

Pin Control Register n (PORTC_PCR20)

32

R/W

See section

11.5.1/183

4004_B054

Pin Control Register n (PORTC_PCR21)

32

R/W

See section

11.5.1/183

4004_B058

Pin Control Register n (PORTC_PCR22)

32

R/W

See section

11.5.1/183

4004_B05C Pin Control Register n (PORTC_PCR23)

32

R/W

See section

11.5.1/183

4004_B060

Pin Control Register n (PORTC_PCR24)

32

R/W

See section

11.5.1/183

4004_B064

Pin Control Register n (PORTC_PCR25)

32

R/W

See section

11.5.1/183

4004_B068

Pin Control Register n (PORTC_PCR26)

32

R/W

See section

11.5.1/183

4004_B06C Pin Control Register n (PORTC_PCR27)

32

R/W

See section

11.5.1/183

4004_B070

Pin Control Register n (PORTC_PCR28)

32

R/W

See section

11.5.1/183

4004_B074

Pin Control Register n (PORTC_PCR29)

32

R/W

See section

11.5.1/183

4004_B078

Pin Control Register n (PORTC_PCR30)

32

R/W

See section

11.5.1/183

4004_B07C Pin Control Register n (PORTC_PCR31)

32

R/W

See section

11.5.1/183

4004_B080

Global Pin Control Low Register (PORTC_GPCLR)

32

W
(always 0000_0000h
reads 0)

11.5.2/185

4004_B084

Global Pin Control High Register (PORTC_GPCHR)

32

W
(always 0000_0000h
reads 0)

11.5.3/186

4004_B0A0 Interrupt Status Flag Register (PORTC_ISFR)

32

w1c

0000_0000h

11.5.4/186

4004_C000

Pin Control Register n (PORTD_PCR0)

32

R/W

See section

11.5.1/183

4004_C004

Pin Control Register n (PORTD_PCR1)

32

R/W

See section

11.5.1/183

4004_C008

Pin Control Register n (PORTD_PCR2)

32

R/W

See section

11.5.1/183

4004_C00C Pin Control Register n (PORTD_PCR3)

32

R/W

See section

11.5.1/183

4004_C010

Pin Control Register n (PORTD_PCR4)

32

R/W

See section

11.5.1/183

4004_C014

Pin Control Register n (PORTD_PCR5)

32

R/W

See section

11.5.1/183

4004_C018

Pin Control Register n (PORTD_PCR6)

32

R/W

See section

11.5.1/183

4004_C01C Pin Control Register n (PORTD_PCR7)

32

R/W

See section

11.5.1/183

Table continues on the next page...

KL25 Sub-Family Reference Manual, Rev. 3, September 2012
180

Freescale Semiconductor, Inc.

Chapter 11 Port control and interrupts (PORT)

PORT memory map (continued)
Absolute
address
(hex)

Register name

Width
Access
(in bits)

Reset value

Section/
page

4004_C020

Pin Control Register n (PORTD_PCR8)

32

R/W

See section

11.5.1/183

4004_C024

Pin Control Register n (PORTD_PCR9)

32

R/W

See section

11.5.1/183

4004_C028

Pin Control Register n (PORTD_PCR10)

32

R/W

See section

11.5.1/183

4004_C02C Pin Control Register n (PORTD_PCR11)

32

R/W

See section

11.5.1/183

4004_C030

Pin Control Register n (PORTD_PCR12)

32

R/W

See section

11.5.1/183

4004_C034

Pin Control Register n (PORTD_PCR13)

32

R/W

See section

11.5.1/183

4004_C038

Pin Control Register n (PORTD_PCR14)

32

R/W

See section

11.5.1/183

4004_C03C Pin Control Register n (PORTD_PCR15)

32

R/W

See section

11.5.1/183

4004_C040

Pin Control Register n (PORTD_PCR16)

32

R/W

See section

11.5.1/183

4004_C044

Pin Control Register n (PORTD_PCR17)

32

R/W

See section

11.5.1/183

4004_C048

Pin Control Register n (PORTD_PCR18)

32

R/W

See section

11.5.1/183

4004_C04C Pin Control Register n (PORTD_PCR19)

32

R/W

See section

11.5.1/183

4004_C050

Pin Control Register n (PORTD_PCR20)

32

R/W

See section

11.5.1/183

4004_C054

Pin Control Register n (PORTD_PCR21)

32

R/W

See section

11.5.1/183

4004_C058

Pin Control Register n (PORTD_PCR22)

32

R/W

See section

11.5.1/183

4004_C05C Pin Control Register n (PORTD_PCR23)

32

R/W

See section

11.5.1/183

4004_C060

Pin Control Register n (PORTD_PCR24)

32

R/W

See section

11.5.1/183

4004_C064

Pin Control Register n (PORTD_PCR25)

32

R/W

See section

11.5.1/183

4004_C068

Pin Control Register n (PORTD_PCR26)

32

R/W

See section

11.5.1/183

4004_C06C Pin Control Register n (PORTD_PCR27)

32

R/W

See section

11.5.1/183

4004_C070

Pin Control Register n (PORTD_PCR28)

32

R/W

See section

11.5.1/183

4004_C074

Pin Control Register n (PORTD_PCR29)

32

R/W

See section

11.5.1/183

4004_C078

Pin Control Register n (PORTD_PCR30)

32

R/W

See section

11.5.1/183

4004_C07C Pin Control Register n (PORTD_PCR31)

32

R/W

See section

11.5.1/183

4004_C080

Global Pin Control Low Register (PORTD_GPCLR)

32

W
(always 0000_0000h
reads 0)

11.5.2/185

4004_C084

Global Pin Control High Register (PORTD_GPCHR)

32

W
(always 0000_0000h
reads 0)

11.5.3/186

4004_C0A0 Interrupt Status Flag Register (PORTD_ISFR)

32

w1c

0000_0000h

11.5.4/186

4004_D000

Pin Control Register n (PORTE_PCR0)

32

R/W

See section

11.5.1/183

4004_D004

Pin Control Register n (PORTE_PCR1)

32

R/W

See section

11.5.1/183

4004_D008

Pin Control Register n (PORTE_PCR2)

32

R/W

See section

11.5.1/183

4004_D00C Pin Control Register n (PORTE_PCR3)

32

R/W

See section

11.5.1/183

4004_D010

Pin Control Register n (PORTE_PCR4)

32

R/W

See section

11.5.1/183

4004_D014

Pin Control Register n (PORTE_PCR5)

32

R/W

See section

11.5.1/183

4004_D018

Pin Control Register n (PORTE_PCR6)

32

R/W

See section

11.5.1/183

4004_D01C Pin Control Register n (PORTE_PCR7)

32

R/W

See section

11.5.1/183

Table continues on the next page...

KL25 Sub-Family Reference Manual, Rev. 3, September 2012
Freescale Semiconductor, Inc.

181

Memory map and register definition

PORT memory map (continued)
Absolute
address
(hex)

Register name

Width
Access
(in bits)

Reset value

Section/
page

4004_D020

Pin Control Register n (PORTE_PCR8)

32

R/W

See section

11.5.1/183

4004_D024

Pin Control Register n (PORTE_PCR9)

32

R/W

See section

11.5.1/183

4004_D028

Pin Control Register n (PORTE_PCR10)

32

R/W

See section

11.5.1/183

4004_D02C Pin Control Register n (PORTE_PCR11)

32

R/W

See section

11.5.1/183

4004_D030

Pin Control Register n (PORTE_PCR12)

32

R/W

See section

11.5.1/183

4004_D034

Pin Control Register n (PORTE_PCR13)

32

R/W

See section

11.5.1/183

4004_D038

Pin Control Register n (PORTE_PCR14)

32

R/W

See section

11.5.1/183

4004_D03C Pin Control Register n (PORTE_PCR15)

32

R/W

See section

11.5.1/183

4004_D040

Pin Control Register n (PORTE_PCR16)

32

R/W

See section

11.5.1/183

4004_D044

Pin Control Register n (PORTE_PCR17)

32

R/W

See section

11.5.1/183

4004_D048

Pin Control Register n (PORTE_PCR18)

32

R/W

See section

11.5.1/183

4004_D04C Pin Control Register n (PORTE_PCR19)

32

R/W

See section

11.5.1/183

4004_D050

Pin Control Register n (PORTE_PCR20)

32

R/W

See section

11.5.1/183

4004_D054

Pin Control Register n (PORTE_PCR21)

32

R/W

See section

11.5.1/183

4004_D058

Pin Control Register n (PORTE_PCR22)

32

R/W

See section

11.5.1/183

4004_D05C Pin Control Register n (PORTE_PCR23)

32

R/W

See section

11.5.1/183

4004_D060

Pin Control Register n (PORTE_PCR24)

32

R/W

See section

11.5.1/183

4004_D064

Pin Control Register n (PORTE_PCR25)

32

R/W

See section

11.5.1/183

4004_D068

Pin Control Register n (PORTE_PCR26)

32

R/W

See section

11.5.1/183

4004_D06C Pin Control Register n (PORTE_PCR27)

32

R/W

See section

11.5.1/183

4004_D070

Pin Control Register n (PORTE_PCR28)

32

R/W

See section

11.5.1/183

4004_D074

Pin Control Register n (PORTE_PCR29)

32

R/W

See section

11.5.1/183

4004_D078

Pin Control Register n (PORTE_PCR30)

32

R/W

See section

11.5.1/183

4004_D07C Pin Control Register n (PORTE_PCR31)

32

R/W

See section

11.5.1/183

4004_D080

Global Pin Control Low Register (PORTE_GPCLR)

32

W
(always 0000_0000h
reads 0)

11.5.2/185

4004_D084

Global Pin Control High Register (PORTE_GPCHR)

32

W
(always 0000_0000h
reads 0)

11.5.3/186

4004_D0A0 Interrupt Status Flag Register (PORTE_ISFR)

32

w1c

0000_0000h

11.5.4/186

KL25 Sub-Family Reference Manual, Rev. 3, September 2012
182

Freescale Semiconductor, Inc.

Chapter 11 Port control and interrupts (PORT)

11.5.1 Pin Control Register n (PORTx_PCRn)
NOTE
Refer to the Signal Multiplexing and Signal Descriptions
chapter for the reset value of this device.
See the GPIO Configuration section for details on the available
functions for each pin.
Do not modify pin configuration registers associated with pins
not available in your selected package. All un-bonded pins not
available in your package will default to DISABLE state for
lowest power consumption.
Address: Base address + 0h offset + (4d × i), where i=0d to 31d
Bit

31

30

29

28

27

26

25

0

R

24

22

ISF

21

20

19

18

0

Reset

0

0

0

0

0

0

0

0

Bit

15

14

13

12

11

10

9

8

0

R

0

0

0

0

0

x*

x*

0

7

6

0

MUX

W

0

x*

0

DSE
x*

17

16

IRQC

w1c

W

Reset

23

0

0

5

4

0

0

PFE
x*

0

0

0

0

3

2

1

0

SRE

PE

PS

x*

x*

x*

0

0

* Notes:
• x = Undefined at reset.

PORTx_PCRn field descriptions
Field
31–25
Reserved
24
ISF

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
Interrupt Status Flag
This bit is read only for pins that do not support interrupt generation.
The pin interrupt configuration is valid in all digital pin muxing modes.
0
1

Configured interrupt is not detected.
Configured interrupt is detected. If the pin is configured to generate a DMA request, then the
corresponding flag will be cleared automatically at the completion of the requested DMA transfer.
Otherwise, the flag remains set until a logic one is written to the flag. If the pin is configured for a level
sensitive interrupt and the pin remains asserted, then the flag is set again immediately after it is
cleared.
Table continues on the next page...

KL25 Sub-Family Reference Manual, Rev. 3, September 2012
Freescale Semiconductor, Inc.

183

Memory map and register definition

PORTx_PCRn field descriptions (continued)
Field
23–20
Reserved
19–16
IRQC

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
Interrupt Configuration
This field is read only for pins that do not support interrupt generation.
The pin interrupt configuration is valid in all digital pin muxing modes. The corresponding pin is configured
to generate interrupt/DMA request as follows:
0000
0001
0010
0011
1000
1001
1010
1011
1100
Others

15–11
Reserved
10–8
MUX

Interrupt/DMA request disabled.
DMA request on rising edge.
DMA request on falling edge.
DMA request on either edge.
Interrupt when logic zero.
Interrupt on rising edge.
Interrupt on falling edge.
Interrupt on either edge.
Interrupt when logic one.
Reserved.

This field is reserved.
This read-only field is reserved and always has the value 0.
Pin Mux Control
Not all pins support all pin muxing slots. Unimplemented pin muxing slots are reserved and may result in
configuring the pin for a different pin muxing slot.
The corresponding pin is configured in the following pin muxing slot as follows:
000
001
010
011
100
101
110
111

7
Reserved
6
DSE

Pin disabled (analog).
Alternative 1 (GPIO).
Alternative 2 (chip-specific).
Alternative 3 (chip-specific).
Alternative 4 (chip-specific).
Alternative 5 (chip-specific).
Alternative 6 (chip-specific).
Alternative 7 (chip-specific).

This field is reserved.
This read-only field is reserved and always has the value 0.
Drive Strength Enable
This bit is read only for pins that do not support a configurable drive strength.
Drive strength configuration is valid in all digital pin muxing modes.
0
1

5
Reserved
4
PFE

Low drive strength is configured on the corresponding pin, if pin is configured as a digital output.
High drive strength is configured on the corresponding pin, if pin is configured as a digital output.

This field is reserved.
This read-only field is reserved and always has the value 0.
Passive Filter Enable
This bit is read only for pins that do not support a configurable passive input filter.
Passive filter configuration is valid in all digital pin muxing modes.
Table continues on the next page...

KL25 Sub-Family Reference Manual, Rev. 3, September 2012
184

Freescale Semiconductor, Inc.

Chapter 11 Port control and interrupts (PORT)

PORTx_PCRn field descriptions (continued)
Field

Description
0
1

3
Reserved

Passive input filter is disabled on the corresponding pin.
Passive input filter is enabled on the corresponding pin, if the pin is configured as a digital input. Refer
to the device data sheet for filter characteristics.

This field is reserved.
This read-only field is reserved and always has the value 0.

2
SRE

Slew Rate Enable
This bit is read only for pins that do not support a configurable slew rate.
Slew rate configuration is valid in all digital pin muxing modes.
0
1

1
PE

Fast slew rate is configured on the corresponding pin, if the pin is configured as a digital output.
Slow slew rate is configured on the corresponding pin, if the pin is configured as a digital output.

Pull Enable
This bit is read only for pins that do not support a configurable pull resistor. Refer to the Chapter of Signal
Multiplexing and Signal Descriptions for the pins that support a configurable pull resistor.
Pull configuration is valid in all digital pin muxing modes.
0
1

0
PS

Internal pullup or pulldown resistor is not enabled on the corresponding pin.
Internal pullup or pulldown resistor is enabled on the corresponding pin, if the pin is configured as a
digital input.

Pull Select
This bit is read only for pins that do not support a configurable pull resistor direction.
Pull configuration is valid in all digital pin muxing modes.
0
1

Internal pulldown resistor is enabled on the corresponding pin, if the corresponding Port Pull Enable
field is set.
Internal pullup resistor is enabled on the corresponding pin, if the corresponding Port Pull Enable field
is set.

11.5.2 Global Pin Control Low Register (PORTx_GPCLR)
Only 32-bit writes are supported to this register.
Address: Base address + 80h offset
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

R

0

0

W

GPWE

GPWD

Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

6

5

4

3

2

1

0

0

0

0

0

0

0

0

PORTx_GPCLR field descriptions
Field
31–16
GPWE

Description
Global Pin Write Enable
Selects which Pin Control Registers (15 through 0) bits [15:0] update with the value in GPWD.
Table continues on the next page...

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PORTx_GPCLR field descriptions (continued)
Field

Description
0
1

15–0
GPWD

Corresponding Pin Control Register is not updated with the value in GPWD.
Corresponding Pin Control Register is updated with the value in GPWD.

Global Pin Write Data
Write value that is written to all Pin Control Registers bits [15:0] that are selected by GPWE.

11.5.3 Global Pin Control High Register (PORTx_GPCHR)
Only 32-bit writes are supported to this register.
Address: Base address + 84h offset
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

R

0

0

W

GPWE

GPWD

Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

6

5

4

3

2

1

0

0

0

0

0

0

0

0

PORTx_GPCHR field descriptions
Field

Description

31–16
GPWE

Global Pin Write Enable
Selects which Pin Control Registers (31 through 16) bits [15:0] update with the value in GPWD.
0
1

15–0
GPWD

Corresponding Pin Control Register is not updated with the value in GPWD.
Corresponding Pin Control Register is updated with the value in GPWD.

Global Pin Write Data
Write value that is written to all Pin Control Registers bits [15:0] that are selected by GPWE.

11.5.4 Interrupt Status Flag Register (PORTx_ISFR)
The corresponding bit is read only for pins that do not support interrupt generation.
The pin interrupt configuration is valid in all digital pin muxing modes. The Interrupt
Status Flag for each pin is also visible in the corresponding Pin Control Register, and
each flag can be cleared in either location.
Address: Base address + A0h offset
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

R

ISF

W

w1c

Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

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Chapter 11 Port control and interrupts (PORT)

PORTx_ISFR field descriptions
Field
31–0
ISF

Description
Interrupt Status Flag
Each bit in the field indicates the detection of the configured interrupt of the same number as the field.
0
1

Configured interrupt is not detected.
Configured interrupt is detected. If the pin is configured to generate a DMA request, then the
corresponding flag will be cleared automatically at the completion of the requested DMA transfer.
Otherwise, the flag remains set until a logic one is written to the flag. If the pin is configured for a level
sensitive interrupt and the pin remains asserted, then the flag is set again immediately after it is
cleared.

11.6 Functional description
11.6.1 Pin control
Each port pin has a corresponding pin control register, PORT_PCRn, associated with it.
The upper half of the pin control register configures the pin's capability to either interrupt
the CPU or request a DMA transfer, on a rising/falling edge or both edges as well as a
logic level occurring on the port pin. It also includes a flag to indicate that an interrupt
has occurred.
The lower half of the pin control register configures the following functions for each pin
within the 32-bit port.
•
•
•
•

Pullup or pulldown enable on selected pins
Drive strength and slew rate configuration on selected pins
Passive input filter enable on selected pins
Pin Muxing mode

The functions apply across all digital Pin Muxing modes and individual peripherals do
not override the configuration in the pin control register. For example, if an I2C function
is enabled on a pin, that does not override the pullup configuration for that pin.
When the Pin Muxing mode is configured for analog or is disabled, all the digital
functions on that pin are disabled. This includes the pullup and pulldown enables, and
passive filter enable.
The configuration of each pin control register is retained when the PORT module is
disabled.

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Functional description

11.6.2 Global pin control
The two global pin control registers allow a single register write to update the lower half
of the pin control register on up to sixteen pins, all with the same value.
The global pin control registers are designed to enable software to quickly configure
multiple pins within the one port for the same peripheral function. However, the interrupt
functions cannot be configured using the global pin control registers.
The global pin control registers are write-only registers, that always read as zero.

11.6.3 External interrupts
The external interrupt capability of the PORT module is available in all digital pin
muxing modes provided the PORT module is enabled.
Each pin can be individually configured for any of the following external interrupt
modes:
•
•
•
•
•
•
•
•
•

Interrupt disabled, default out of reset
Active high level sensitive interrupt
Active low level sensitive interrupt
Rising edge sensitive interrupt
Falling edge sensitive interrupt
Rising and falling edge sensitive interrupt
Rising edge sensitive DMA request
Falling edge sensitive DMA request
Rising and falling edge sensitive DMA request

The interrupt status flag is set when the configured edge or level is detected on the output
of the pin. When not in Stop mode, the input is first synchronized to the bus clock to
detect the configured level or edge transition.
The PORT module generates a single interrupt that asserts when the interrupt status flag
is set for any enabled interrupt for that port. The interrupt negates after the interrupt status
flags for all enabled interrupts have been cleared by writing a logic 0 to the ISF flag in
the PORT_PCRn register.
The PORT module generates a single DMA request that asserts when the interrupt status
flag is set for any enabled DMA request in that port. The DMA request negates after the
DMA transfer is completed, because that clears the interrupt status flags for all enabled
DMA requests.
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Chapter 11 Port control and interrupts (PORT)

During Stop mode, the interrupt status flag for any enabled interrupt is asynchronously
set if the required level or edge is detected. This also generates an asynchronous wakeup
signal to exit the Low-Power mode.

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Functional description

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Chapter 12
System integration module (SIM)
12.1 Introduction
The system integration module (SIM) provides system control and chip configuration
registers.

12.1.1 Features
• System clocking configuration
• System clock divide values
• Architectural clock gating control
• ERCLK32K clock selection
• USB clock selection
• UART0 and TPM clock selection
• Flash and System RAM size configuration
• USB regulator configuration
• TPM external clock and input capture selection
• UART receive/transmit source selection/configuration

12.2 Memory map and register definition
The SIM module contains many bitfields for selecting the clock source and dividers for
various module clocks.

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Memory map and register definition

NOTE
The SIM registers can be written only in supervisor mode. In
user mode, write accesses are blocked and will result in a bus
error.
NOTE
The SIM_SOPT1 and SIM_SOPT1CFG registers are located at
a different base address than the other SIM registers.
SIM memory map
Absolute
address
(hex)

Register name

Width
Access
(in bits)

Reset value

Section/
page

4004_7000

System Options Register 1 (SIM_SOPT1)

32

R/W

See section

12.2.1/193

4004_7004

SOPT1 Configuration Register (SIM_SOPT1CFG)

32

R/W

0000_0000h

12.2.2/194

4004_8004

System Options Register 2 (SIM_SOPT2)

32

R/W

0000_0000h

12.2.3/195

4004_800C

System Options Register 4 (SIM_SOPT4)

32

R/W

0000_0000h

12.2.4/197

4004_8010

System Options Register 5 (SIM_SOPT5)

32

R/W

0000_0000h

12.2.5/199

4004_8018

System Options Register 7 (SIM_SOPT7)

32

R/W

0000_0000h

12.2.6/200

4004_8024

System Device Identification Register (SIM_SDID)

32

R

See section

12.2.7/202

4004_8034

System Clock Gating Control Register 4 (SIM_SCGC4)

32

R/W

F000_0030h

12.2.8/204

4004_8038

System Clock Gating Control Register 5 (SIM_SCGC5)

32

R/W

0000_0180h

12.2.9/206

4004_803C

System Clock Gating Control Register 6 (SIM_SCGC6)

32

R/W

0000_0001h

12.2.10/207

4004_8040

System Clock Gating Control Register 7 (SIM_SCGC7)

32

R/W

0000_0100h

12.2.11/209

4004_8044

System Clock Divider Register 1 (SIM_CLKDIV1)

32

R/W

See section

12.2.12/210

4004_804C

Flash Configuration Register 1 (SIM_FCFG1)

32

R/W

See section

12.2.13/211

4004_8050

Flash Configuration Register 2 (SIM_FCFG2)

32

R

See section

12.2.14/213

4004_8058

Unique Identification Register Mid-High (SIM_UIDMH)

32

R

See section

12.2.15/213

4004_805C

Unique Identification Register Mid Low (SIM_UIDML)

32

R

See section

12.2.16/214

4004_8060

Unique Identification Register Low (SIM_UIDL)

32

R

See section

12.2.17/214

4004_8100

COP Control Register (SIM_COPC)

32

R/W

4004_8104

Service COP Register (SIM_SRVCOP)

32

W

0000_000Ch 12.2.18/215
0000_0000h

12.2.19/216

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Chapter 12 System integration module (SIM)

12.2.1 System Options Register 1 (SIM_SOPT1)
NOTE
The SOPT1 register is only reset on POR or LVD.
Address: 4004_7000h base + 0h offset = 4004_7000h
29

28

27

26

25

24

23

22

21

20

19

18

17

16

USBVSTBY

30

USBSSTBY

31

USBREGEN

Bit

Reset

1

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Bit

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

*

*

R

W

0

0
OSC32KSEL

0

R

Reserved
W

Reset

0

0

0

0

0

0

0

0

0

0

*

*

*

*

* Notes:
• Reserved field: Device specific value.

SIM_SOPT1 field descriptions
Field
31
USBREGEN

Description
USB voltage regulator enable
Controls whether the USB voltage regulator is enabled.
0
1

30
USBSSTBY

USB voltage regulator in standby mode during Stop, VLPS, LLS and VLLS modes.
Controls whether the USB voltage regulator is placed in standby mode during Stop, VLPS, LLS and VLLS
modes.
0
1

29
USBVSTBY

USB voltage regulator not in standby during Stop, VLPS, LLS and VLLS modes.
USB voltage regulator in standby during Stop, VLPS, LLS and VLLS modes.

USB voltage regulator in standby mode during VLPR and VLPW modes
Controls whether the USB voltage regulator is placed in standby mode during VLPR and VLPW modes.
0
1

28–20
Reserved

USB voltage regulator is disabled.
USB voltage regulator is enabled.

USB voltage regulator not in standby during VLPR and VLPW modes.
USB voltage regulator in standby during VLPR and VLPW modes.

This field is reserved.
This read-only field is reserved and always has the value 0.
Table continues on the next page...

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SIM_SOPT1 field descriptions (continued)
Field

Description

19–18
OSC32KSEL

32K oscillator clock select
Selects the 32 kHz clock source (ERCLK32K) for RTC and LPTMR. This bit is reset only on POR/LVD.
00
01
10
11

System oscillator (OSC32KCLK)
Reserved
RTC_CLKIN
LPO 1kHz

17–6
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

5–0
Reserved

This field is reserved.

12.2.2 SOPT1 Configuration Register (SIM_SOPT1CFG)
NOTE
The SOPT1CFG register is reset on System Reset not VLLS.
Address: 4004_7000h base + 4h offset = 4004_7004h
Bit

31

30

29

28

27

0

24

23

22

21

20

19

18

17

16

URWE

0

UVSWE

25

USSWE

R

26

Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Bit

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

0

0

0

0

0

0

0

W

0

R

W

Reset

0

0

0

0

0

0

0

0

SIM_SOPT1CFG field descriptions
Field
31–27
Reserved
26
USSWE

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
USB voltage regulator stop standby write enable
Writing one to the USSWE bit allows the SOPT1 USBSSTBY bit to be written. This register bit clears after
a write to USBSSTBY.
Table continues on the next page...

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Chapter 12 System integration module (SIM)

SIM_SOPT1CFG field descriptions (continued)
Field

Description
0
1

25
UVSWE

SOPT1 USBSSTB cannot be written.
SOPT1 USBSSTB can be written.

USB voltage regulator VLP standby write enable
Writing one to the UVSWE bit allows the SOPT1 USBVSTBY bit to be written. This register bit clears after
a write to USBVSTBY.
0
1

24
URWE

SOPT1 USBVSTB cannot be written.
SOPT1 USBVSTB can be written.

USB voltage regulator enable write enable
Writing one to the URWE bit allows the SOPT1 USBREGEN bit to be written. This register bit clears after
a write to USBREGEN.
0
1

23–0
Reserved

SOPT1 USBREGEN cannot be written.
SOPT1 USBREGEN can be written.

This field is reserved.
This read-only field is reserved and always has the value 0.

12.2.3 System Options Register 2 (SIM_SOPT2)
SOPT2 contains the controls for selecting many of the module clock source options on
this device. See the Clock Distribution chapter for more information including clocking
diagrams and definitions of device clocks.
31

30

29

28

27

26

25

24

23

22

21

0

R

20

19

0
UART0SRC

18

USBSRC

Bit

TPMSRC

W

17

16

0

PLLFLLSEL

Address: 4004_7000h base + 1004h offset = 4004_8004h

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Bit

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

0

RTCCLKOUTS
EL

Reset

0

R

CLKOUTSEL
W

Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

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Memory map and register definition

SIM_SOPT2 field descriptions
Field
31–28
Reserved
27–26
UART0SRC

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
UART0 clock source select
Selects the clock source for the UART0 transmit and receive clock.
00
01
10
11

25–24
TPMSRC

Clock disabled
MCGFLLCLK clock or MCGPLLCLK/2 clock
OSCERCLK clock
MCGIRCLK clock

TPM clock source select
Selects the clock source for the TPM counter clock
00
01
10
11

Clock disabled
MCGFLLCLK clock or MCGPLLCLK/2
OSCERCLK clock
MCGIRCLK clock

23–19
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

18
USBSRC

USB clock source select
Selects the clock source for the USB 48 MHz clock.
0
1

17
Reserved
16
PLLFLLSEL

This field is reserved.
This read-only field is reserved and always has the value 0.
PLL/FLL clock select
Selects the MCGPLLCLK or MCGFLLCLK clock for various peripheral clocking options.
0
1

15–8
Reserved
7–5
CLKOUTSEL

External bypass clock (USB_CLKIN).
MCGPLLCLK/2 or MCGFLLCLK clock

MCGFLLCLK clock
MCGPLLCLK clock with fixed divide by two

This field is reserved.
This read-only field is reserved and always has the value 0.
CLKOUT select
Selects the clock to output on the CLKOUT pin.
000
001
010
011
100
101
110
111

Reserved
Reserved
Bus clock
LPO clock (1 kHz)
MCGIRCLK
Reserved
OSCERCLK
Reserved

4
RTC clock out select
RTCCLKOUTSEL
Table continues on the next page...

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Chapter 12 System integration module (SIM)

SIM_SOPT2 field descriptions (continued)
Field

Description
Selects either the RTC 1 Hz clock or the OSC clock to be output on the RTC_CLKOUT pin.
0
1

3–0
Reserved

RTC 1 Hz clock is output on the RTC_CLKOUT pin.
OSCERCLK clock is output on the RTC_CLKOUT pin.

This field is reserved.
This read-only field is reserved and always has the value 0.

12.2.4 System Options Register 4 (SIM_SOPT4)
Address: 4004_7000h base + 100Ch offset = 4004_800Ch
27

26

25

24

23

22

21

20

19

18

17

TPM1CH0SRC

28

TPM2CH0SRC

29

16

TPM0CLKSEL

30

TPM1CLKSEL

31

TPM2CLKSEL

Bit

Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Bit

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

0

0

0

0

0

0

0

0

R

W

0

0

0

0

R

W

Reset

0

0

0

0

0

0

0

0

SIM_SOPT4 field descriptions
Field
31–27
Reserved
26
TPM2CLKSEL

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
TPM2 External Clock Pin Select
Selects the external pin used to drive the clock to the TPM2 module.
NOTE: The selected pin must also be configured for the TPM external clock function through the
appropriate pin control register in the port control module.
0
1

25
TPM1CLKSEL

TPM2 external clock driven by TPM_CLKIN0 pin.
TPM2 external clock driven by TPM_CLKIN1 pin.

TPM1 External Clock Pin Select
Selects the external pin used to drive the clock to the TPM1 module.
NOTE: The selected pin must also be configured for the TPM external clock function through the
appropriate pin control register in the port control module.
Table continues on the next page...

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Memory map and register definition

SIM_SOPT4 field descriptions (continued)
Field

Description
0
1

24
TPM0CLKSEL

TPM1 external clock driven by TPM_CLKIN0 pin.
TPM1 external clock driven by TPM_CLKIN1 pin.

TPM0 External Clock Pin Select
Selects the external pin used to drive the clock to the TPM0 module.
NOTE: The selected pin must also be configured for the TPM external clock function through the
appropriate pin control register in the port control module.
0
1

23–21
Reserved
20
TPM2CH0SRC

TPM0 external clock driven by TPM_CLKIN0 pin.
TPM0 external clock driven by TPM_CLKIN1 pin.

This field is reserved.
This read-only field is reserved and always has the value 0.
TPM2 channel 0 input capture source select
Selects the source for TPM2 channel 0 input capture.
NOTE: When TPM2 is not in input capture mode, clear this field.
0
1

19
Reserved
18
TPM1CH0SRC

TPM2_CH0 signal
CMP0 output

This field is reserved.
This read-only field is reserved and always has the value 0.
TPM1 channel 0 input capture source select
Selects the source for TPM1 channel 0 input capture.
NOTE: When TPM1 is not in input capture mode, clear this field.
0
1

17–0
Reserved

TPM1_CH0 signal
CMP0 output

This field is reserved.
This read-only field is reserved and always has the value 0.

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Chapter 12 System integration module (SIM)

12.2.5 System Options Register 5 (SIM_SOPT5)
Address: 4004_7000h base + 1010h offset = 4004_8010h
29

28

27

26

25

24

23

22

21

20

19

18

17

16

0

Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Bit

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

R

W

Reset

0

0

0

0

0

0

0

0

0

0

UART1TXSRC

UART1RXSRC

W

0

0

0

0

0

UART0TXSRC

0

R

UART0RXSRC

UART0ODE

30

UART1ODE

31

UART2ODE

Bit

0

0

SIM_SOPT5 field descriptions
Field

Description

31–20
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

19
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

18
UART2ODE

UART2 Open Drain Enable

17
UART1ODE

UART1 Open Drain Enable

16
UART0ODE

UART0 Open Drain Enable

15–7
Reserved
6
UART1RXSRC

0
1

0
1

0
1

Open drain is disabled on UART1
Open drain is enabled on UART1

Open drain is disabled on UART0
Open drain is enabled on UART0

This field is reserved.
This read-only field is reserved and always has the value 0.
UART1 receive data source select
Selects the source for the UART1 receive data.
0
1

5–4
UART1TXSRC

Open drain is disabled on UART2
Open drain is enabled on UART2

UART1_RX pin
CMP0 output

UART1 transmit data source select
Selects the source for the UART1 transmit data.
Table continues on the next page...

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Memory map and register definition

SIM_SOPT5 field descriptions (continued)
Field

Description
00
01
10
11

3
Reserved

UART1_TX pin
UART1_TX pin modulated with TPM1 channel 0 output
UART1_TX pin modulated with TPM2 channel 0 output
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

2
UART0RXSRC

UART0 receive data source select
Selects the source for the UART0 receive data.
0
1

1–0
UART0TXSRC

UART0_RX pin
CMP0 output

UART0 transmit data source select
Selects the source for the UART0 transmit data.
00
01
10
11

UART0_TX pin
UART0_TX pin modulated with TPM1 channel 0 output
UART0_TX pin modulated with TPM2 channel 0 output
Reserved

12.2.6 System Options Register 7 (SIM_SOPT7)
Address: 4004_7000h base + 1018h offset = 4004_8018h
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

0

R

W

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Bit

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

R

W

Reset

0

0

0

0

0

0

0

0

0

ADC0PRETRGS
EL

0

ADC0ALTTRGE
N

Reset

0

0

0

ADC0TRGSEL

0

0

0

0

0

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SIM_SOPT7 field descriptions
Field
31–8
Reserved

Description
This field is reserved.
This read-only field is reserved and always has the value 0.

7
ADC0 alternate trigger enable
ADC0ALTTRGEN
Enable alternative conversion triggers for ADC0.
0
1
6–5
Reserved

TPM1 channel 0 (A) and channel 1 (B) triggers selected for ADC0.
Alternate trigger selected for ADC0.

This field is reserved.
This read-only field is reserved and always has the value 0.

4
ADC0 pretrigger select
ADC0PRETRGSEL
Selects the ADC0 pre-trigger source when alternative triggers are enabled through ADC0ALTTRGEN.
0
1
3–0
ADC0TRGSEL

Pre-trigger A
Pre-trigger B

ADC0 trigger select
Selects the ADC0 trigger source when alternative triggers are functional in stop and VLPS modes. .
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111

External trigger pin input (EXTRG_IN)
CMP0 output
Reserved
Reserved
PIT trigger 0
PIT trigger 1
Reserved
Reserved
TPM0 overflow
TPM1 overflow
TPM2 overflow
Reserved
RTC alarm
RTC seconds
LPTMR0 trigger
Reserved

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12.2.7 System Device Identification Register (SIM_SDID)
Address: 4004_7000h base + 1024h offset = 4004_8024h
Bit

31

30

29

28

FAMID

R

27

26

25

24

23

SUBFAMID

22

21

20

SERIESID

19

18

17

16

15

SRAMSIZE

14

13

12

11

10

REVID

9

8

7

6

DIEID

5

4

3

0

2

1

0

PINID

W
Reset

*

*

*

*

*

*

*

*

0

0

0

1

*

*

*

*

*

*

*

*

0

1

0

0

1

0

0

0

*

*

*

*

* Notes:
• FAMID field: Device specific value.
• SUBFAMID field: Device specific value.
• SRAMSIZE field: Device specific value.
• REVID field: Device specific value.
• PINID field: Device specific value.

SIM_SDID field descriptions
Field
31–28
FAMID

Description
Kinetis family ID
Specifies the Kinetis family of the device.
0000
0001
0010
0011
0100

27–24
SUBFAMID

Kinetis Sub-Family ID
Specifies the Kinetis sub-family of the device.
0010
0100
0101
0110

23–20
SERIESID

KLx2 Subfamily (low end)
KLx4 Subfamily (basic analog)
KLx5 Subfamily (advanced analog)
KLx6 Subfamily (advanced analog with I2S)

Kinetis Series ID
Specifies the Kinetis family of the device.
0001

19–16
SRAMSIZE

KL0x Family (low end)
KL1x Family (basic)
KL2x Family (USB)
KL3x Family (Segment LCD)
KL4x Family (USB and Segment LCD)

KL family

System SRAM Size
Specifies the size of the System SRAM
0000
0001
0010
0011
0100
0101

0.5 KB
1 KB
2 KB
4 KB
8 KB
16 KB
Table continues on the next page...

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Chapter 12 System integration module (SIM)

SIM_SDID field descriptions (continued)
Field

Description
0110
0111

32 KB
64 KB

15–12
REVID

Device revision number

11–7
DIEID

Device die number

6–4
Reserved
3–0
PINID

Specifies the silicon implementation number for the device.

Specifies the silicon implementation number for the device.
This field is reserved.
This read-only field is reserved and always has the value 0.
Pincount identification
Specifies the pincount of the device.
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111

16-pin
24-pin
32-pin
Reserved
48-pin
64-pin
80-pin
Reserved
100-pin
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved

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12.2.8 System Clock Gating Control Register 4 (SIM_SCGC4)
Address: 4004_7000h base + 1034h offset = 4004_8034h
31

30

29

28

27

26

1

R

25

24

23

22

SPI1

SPI0

21

0

20

19

0

18

CMP

USBOTG

Bit

W

17

16

0

1

1

0

0

0

0

0

0

0

0

0

0

0

0

Bit

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

0

0

R

0

W

Reset

0

0

0

UART0

1

UART1

1

UART2

Reset

0

0

0

0

0

1

0

I2C1

I2C0

0

0

1

0

1

0

0

SIM_SCGC4 field descriptions
Field

Description

31–28
Reserved

This field is reserved.
This read-only field is reserved and always has the value 1.

27–24
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

23
SPI1

SPI1 Clock Gate Control
This bit controls the clock gate to the SPI1 module.
0
1

22
SPI0

SPI0 Clock Gate Control
This bit controls the clock gate to the SPI0 module.
0
1

21–20
Reserved
19
CMP

Clock disabled
Clock enabled

This field is reserved.
This read-only field is reserved and always has the value 0.
Comparator Clock Gate Control
This bit controls the clock gate to the comparator module.
0
1

18
USBOTG

Clock disabled
Clock enabled

Clock disabled
Clock enabled

USB Clock Gate Control
This bit controls the clock gate to the USB module.
Table continues on the next page...

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Chapter 12 System integration module (SIM)

SIM_SCGC4 field descriptions (continued)
Field

Description
0
1

Clock disabled
Clock enabled

17–14
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

13
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

12
UART2

UART2 Clock Gate Control
This bit controls the clock gate to the UART2 module.
0
1

11
UART1

UART1 Clock Gate Control
This bit controls the clock gate to the UART1 module.
0
1

10
UART0

7
I2C1

This bit controls the clock gate to the UART0 module.
Clock disabled
Clock enabled

This field is reserved.
This read-only field is reserved and always has the value 0.
I2C1 Clock Gate Control
This bit controls the clock gate to the I 2 C1 module.
0
1

6
I2C0

Clock disabled
Clock enabled

UART0 Clock Gate Control

0
1
9–8
Reserved

Clock disabled
Clock enabled

Clock disabled
Clock enabled

I2C0 Clock Gate Control
This bit controls the clock gate to the I 2 C0 module.
0
1

Clock disabled
Clock enabled

5–4
Reserved

This field is reserved.
This read-only field is reserved and always has the value 1.

3–0
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

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12.2.9 System Clock Gating Control Register 5 (SIM_SCGC5)
Address: 4004_7000h base + 1038h offset = 4004_8038h
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

0

R

18

0

17

16

0

W

0

0

0

0

0

0

0

0

0

0

0

Bit

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

R

W

Reset

0

0

0

0

0

0

0

1

0

0

0

TSI

1

1

0

0

0

0

0

0

LPTMR

0

PORTA

0

PORTB

0

PORTC

0

PORTD

0

PORTE

Reset

0

SIM_SCGC5 field descriptions
Field

Description

31–20
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

19
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

18–14
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

13
PORTE

Port E Clock Gate Control
This bit controls the clock gate to the Port E module.
0
1

12
PORTD

Port D Clock Gate Control
This bit controls the clock gate to the Port D module.
0
1

11
PORTC

Clock disabled
Clock enabled

Port C Clock Gate Control
This bit controls the clock gate to the Port C module.
0
1

10
PORTB

Clock disabled
Clock enabled

Clock disabled
Clock enabled

Port B Clock Gate Control
This bit controls the clock gate to the Port B module.
Table continues on the next page...

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Chapter 12 System integration module (SIM)

SIM_SCGC5 field descriptions (continued)
Field

Description
0
1

9
PORTA

Clock disabled
Clock enabled

Port A Clock Gate Control
This bit controls the clock gate to the Port A module.
0
1

Clock disabled
Clock enabled

8–7
Reserved

This field is reserved.
This read-only field is reserved and always has the value 1.

6
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

5
TSI

TSI Access Control
This bit controls software access to the TSI module.
0
1

Access disabled
Access enabled

4–2
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

1
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

0
LPTMR

Low Power Timer Access Control
This bit controls software access to the Low Power Timer module.
0
1

Access disabled
Access enabled

12.2.10 System Clock Gating Control Register 6 (SIM_SCGC6)
Address: 4004_7000h base + 103Ch offset = 4004_803Ch
Bit

31

29

28

23

22

21

20

19

18

17

16

Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Bit

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

R

0

DMAMUX

0

TPM0

24

TPM1

25

TPM2

0

26

ADC0

0

27

PIT

FTF

0

1

W

DAC0

R

30

RTC

0

W

Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

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SIM_SCGC6 field descriptions
Field
31
DAC0

Description
DAC0 Clock Gate Control
This bit controls the clock gate to the DAC0 module.
0
1

30
Reserved
29
RTC

This field is reserved.
This read-only field is reserved and always has the value 0.
RTC Access Control
This bit controls software access and interrupts to the RTC module.
0
1

28
Reserved
27
ADC0

ADC0 Clock Gate Control
This bit controls the clock gate to the ADC0 module.

This bit controls the clock gate to the TPM2 module.

This bit controls the clock gate to the TPM1 module.
Clock disabled
Clock enabled

TPM0 Clock Gate Control
This bit controls the clock gate to the TPM0 module.
0
1

23
PIT

Clock disabled
Clock enabled

TPM1 Clock Gate Control

0
1
24
TPM0

Clock disabled
Clock enabled

TPM2 Clock Gate Control

0
1
25
TPM1

Access and interrupts disabled
Access and interrupts enabled

This field is reserved.
This read-only field is reserved and always has the value 0.

0
1
26
TPM2

Clock disabled
Clock enabled

Clock disabled
Clock enabled

PIT Clock Gate Control
This bit controls the clock gate to the PIT module.
0
1

Clock disabled
Clock enabled

22–16
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

15
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.
Table continues on the next page...

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Chapter 12 System integration module (SIM)

SIM_SCGC6 field descriptions (continued)
Field

Description

14–2
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

1
DMAMUX

DMA Mux Clock Gate Control
This bit controls the clock gate to the DMA Mux module.
0
1

0
FTF

Clock disabled
Clock enabled

Flash Memory Clock Gate Control
This bit controls the clock gate to the flash memory. Flash reads are still supported while the flash memory
is clock gated, but entry into low power modes is blocked.
0
1

Clock disabled
Clock enabled

12.2.11 System Clock Gating Control Register 7 (SIM_SCGC7)
Address: 4004_7000h base + 1040h offset = 4004_8040h
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

0

R
W

Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Bit

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

0

0

0

0

R

Reset

0

0

0

0

0

DMA

W

0

0

0

1

0

0

0

0

SIM_SCGC7 field descriptions
Field
31–9
Reserved
8
DMA

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
DMA Clock Gate Control
This bit controls the clock gate to the DMA module.
0
1

7–0
Reserved

Clock disabled
Clock enabled

This field is reserved.
This read-only field is reserved and always has the value 0.

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12.2.12 System Clock Divider Register 1 (SIM_CLKDIV1)
NOTE
The CLKDIV1 register cannot be written to when the device is
in VLPR mode.
NOTE
Reset value loaded during System Reset from
FTF_FOPT[LPBOOT].
Address: 4004_7000h base + 1044h offset = 4004_8044h
Bit

31

R

29

28

27

26

25

24

*

*

*

23

22

21

20

19

0

OUTDIV1

W
Reset

30

*

0

0

0

0

0

18

17

16

15

14

13

12

11

10

9

8

OUTDIV4
0

0

0

0

0

0

1

7

6

5

4

3

2

1

0

0

0

0

0

0

0

0

0

0
0

0

0

0

0

0

0

0

* Notes:
• OUTDIV1 field: The reset value depends on the FTF_FOPT[LPBOOT]. it is loaded with 0000 (divide by one), 0001 (divide
by two), 0011 (divide by four), or 0111 (divide by eight).

SIM_CLKDIV1 field descriptions
Field
31–28
OUTDIV1

Description
Clock 1 output divider value
This field sets the divide value for the core/system clock, as well as the bus/flash clocks. At the end of
reset, it is loaded with 0000 (divide by one), 0001 (divide by two), 0011 (divide by four), or 0111 (divide by
eight) depending on the setting of the two FTF_FOPT[LPBOOT] configuration bits.
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111

27–19
Reserved

Divide-by-1.
Divide-by-2.
Divide-by-3.
Divide-by-4.
Divide-by-5.
Divide-by-6.
Divide-by-7.
Divide-by-8.
Divide-by-9.
Divide-by-10.
Divide-by-11.
Divide-by-12.
Divide-by-13.
Divide-by-14.
Divide-by-15.
Divide-by-16.

This field is reserved.
This read-only field is reserved and always has the value 0.
Table continues on the next page...

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SIM_CLKDIV1 field descriptions (continued)
Field

Description

18–16
OUTDIV4

Clock 4 output divider value
This field sets the divide value for the bus and flash clock and is in addition to the System clock divide
ratio. At the end of reset, it is loaded with 0001 (divide by two).
000
001
010
011
100
101
110
111

15–0
Reserved

Divide-by-1.
Divide-by-2.
Divide-by-3.
Divide-by-4.
Divide-by-5.
Divide-by-6.
Divide-by-7.
Divide-by-8.

This field is reserved.
This read-only field is reserved and always has the value 0.

12.2.13 Flash Configuration Register 1 (SIM_FCFG1)
Address: 4004_7000h base + 104Ch offset = 4004_804Ch
Bit

31

30

29

28

27

0

R

26

25

24

23

22

21

20

PFSIZE

19

18

17

16

0

Reset

0

0

0

0

*

*

*

*

0

0

0

0

0

0

0

0

Bit

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

FLASHDOZE

FLASHDIS

W

0

0

0

0

0

0

0

0

0

0

R

W

Reset

0

0

0

0

0

0

0

* Notes:
• PFSIZE field: Device specific value.

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SIM_FCFG1 field descriptions
Field
31–28
Reserved
27–24
PFSIZE

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
Program flash size
This field specifies the amount of program flash memory available on the device . Undefined values are
reserved.
0000
0001
0011
0101
0111
1001
1111

23–2
Reserved
1
FLASHDOZE

This field is reserved.
This read-only field is reserved and always has the value 0.
Flash Doze
When set, Flash memory is disabled for the duration of Doze mode. This bit should be clear during VLP
modes. The Flash will be automatically enabled again at the end of Doze mode so interrupt vectors do not
need to be relocated out of Flash memory. The wakeup time from Doze mode is extended when this bit is
set. An attempt by the DMA or other bus master to access the Flash when the Flash is disabled will result
in a bus error.
0
1

0
FLASHDIS

8 KB of program flash memory, 0.25 KB protection region
16 KB of program flash memory, 0.5 KB protection region
32 KB of program flash memory, 1 KB protection region
64 KB of program flash memory, 2 KB protection region
128 KB of program flash memory, 4 KB protection region
256 KB of program flash memory, 8 KB protection region
128 KB of program flash memory, 4 KB protection region

Flash remains enabled during Doze mode
Flash is disabled for the duration of Doze mode

Flash Disable
Flash accesses are disabled (and generate a bus error) and the Flash memory is placed in a low power
state. This bit should not be changed during VLP modes. Relocate the interrupt vectors out of Flash
memory before disabling the Flash.
0
1

Flash is enabled
Flash is disabled

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12.2.14 Flash Configuration Register 2 (SIM_FCFG2)
Address: 4004_7000h base + 1050h offset = 4004_8050h
Bit

31

R

0

30

29

28

27

26

25

24

23

MAXADDR0

22

21

20

19

1

18

17

16

0

W

Reset

0

*

*

*

*

*

*

*

1

0

0

0

0

0

0

0

Bit

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

0

0

0

0

0

0

0

0

R
W

Reset

0

0

0

0

0

0

0

0

* Notes:
• MAXADDR0 field: Device specific value indicating amount of implemented flash.

SIM_FCFG2 field descriptions
Field

Description

31
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

30–24
MAXADDR0

Max address block
This field concatenated with leading zeros indicates the first invalid address of program flash.
For example, if MAXADDR0 = 0x10 the first invalid address of program flash is 0x0002_0000. This would
be the MAXADDR0 value for a device with 128 KB program flash.

23
Reserved

This field is reserved.
This read-only field is reserved and always has the value 1.

22–16
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

15–0
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

12.2.15 Unique Identification Register Mid-High (SIM_UIDMH)
Address: 4004_7000h base + 1058h offset = 4004_8058h
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

0

R

8

7

6

5

4

3

2

1

0

*

*

*

*

*

*

*

UID

W
Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

*

*

*

*

*

*

*

*

*

* Notes:
• UID field: Device specific value.

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SIM_UIDMH field descriptions
Field

Description

31–16
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

15–0
UID

Unique Identification
Unique identification for the device.

12.2.16 Unique Identification Register Mid Low (SIM_UIDML)
Address: 4004_7000h base + 105Ch offset = 4004_805Ch
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

*

*

*

*

*

*

*

*

*

*

*

*

*

*

*

UID

R
W
Reset

*

*

*

*

*

*

*

*

*

*

*

*

*

*

*

*

*

* Notes:
• UID field: Device specific value.

SIM_UIDML field descriptions
Field

Description

31–0
UID

Unique Identification
Unique identification for the device.

12.2.17 Unique Identification Register Low (SIM_UIDL)
Address: 4004_7000h base + 1060h offset = 4004_8060h
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

*

*

*

*

*

*

*

*

*

*

*

*

*

*

*

UID

R
W
Reset

*

*

*

*

*

*

*

*

*

*

*

*

*

*

*

*

*

* Notes:
• UID field: Device specific value.

SIM_UIDL field descriptions
Field
31–0
UID

Description
Unique Identification
Unique identification for the device.

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Chapter 12 System integration module (SIM)

12.2.18 COP Control Register (SIM_COPC)
All of the bits in this register can be written only once after a reset.
Address: 4004_7000h base + 1100h offset = 4004_8100h
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

0

R

Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Bit

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

COPCLKS

COPW

W

0

0

0

R

COPT
W

Reset

0

0

0

0

0

0

0

0

0

0

0

0

1

1

SIM_COPC field descriptions
Field
31–4
Reserved
3–2
COPT

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
COP Watchdog Timeout
These write-once bits select the timeout period of the COP. The COPT field along with the COPCLKS bit
define the COP timeout period.
00
01
10
11

1
COPCLKS

COP Clock Select
This write-once bit selects the clock source of the COP watchdog.
0
1

0
COPW

COP disabled
COP timeout after 25 LPO cycles or 213 bus clock cycles
COP timeout after 28 LPO cycles or 216 bus clock cycles
COP timeout after 210 LPO cycles or 218 bus clock cycles

Internal 1 kHz clock is source to COP
Bus clock is source to COP

COP windowed mode
Windowed mode is only supported when COP is running from the bus clock. The COP window is opened
three quarters through the timeout period.
0
1

Normal mode
Windowed mode

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Functional description

12.2.19 Service COP Register (SIM_SRVCOP)
Address: 4004_7000h base + 1104h offset = 4004_8104h
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

0

0

R

Reserved

W
Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

SRVCOP
0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

SIM_SRVCOP field descriptions
Field

Description

31–8
Reserved

This field is reserved.

7–0
SRVCOP

Sevice COP Register
Write 0x55 and then 0xAA (in that order) to reset the COP timeout counter.

12.3 Functional description
See Introduction section.

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Chapter 13
System Mode Controller (SMC)
13.1 Introduction
NOTE
For the chip-specific implementation details of this module's
instances see the chip configuration information.
The system mode controller (SMC) is responsible for sequencing the system into and out
of all low power stop and run modes. Specifically, it monitors events to trigger transitions
between power modes while controlling the power, clocks, and memories of the system
to achieve the power consumption and functionality of that mode.
This chapter describes all the available low power modes, the sequence followed to enter/
exit each mode, and the functionality available while in each of the modes.
The SMC is able to function during even the deepest low power modes.

13.2 Modes of operation
The ARM CPU has three primary modes of operation:
• Run
• Sleep
• Deep Sleep
The WFI or WFE instruction is used to invoke Sleep and Deep Sleep modes. Run, wait
and stop are the common terms used for the primary operating modes of Freescale
microcontrollers. The following table shows the translation between the ARM CPU
modes and the Freescale MCU power modes.

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Modes of operation

ARM CPU mode

MCU mode

Sleep

Wait

Deep Sleep

Stop

Accordingly, the ARM CPU documentation refers to sleep and deep sleep, while the
Freescale MCU documentation normally uses wait and stop.
In addition, Freescale MCUs also augment stop, wait, and run modes in a number of
ways. The power management controller (PMC) contains a run and a stop mode
regulator. Run regulation is used in normal run, wait and stop modes. Stop mode
regulation is used during all very low power and low leakage modes. During stop mode
regulation, the bus frequencies are limited in the very low power modes.
The SMC provides the user with multiple power options. The Very Low Power Run
(VLPR) mode can drastically reduce run time power when maximum bus frequency is
not required to handle the application needs. From Normal Run mode, the Run Mode
(RUNM) field can be modified to change the MCU into VLPR mode when limited
frequency is sufficient for the application. From VLPR mode, a corresponding wait
(VLPW) and stop (VLPS) mode can be entered.
Depending on the needs of the user application, a variety of stop modes are available that
allow the state retention, partial power down or full power down of certain logic and/or
memory. I/O states are held in all modes of operation. Several registers are used to
configure the various modes of operation for the device.
The following table describes the power modes available for the device.
Table 13-1. Power modes
Mode

Description

RUN

The MCU can be run at full speed and the internal supply is fully regulated, that is, in run regulation.
This mode is also referred to as Normal Run mode.

WAIT

The core clock is gated off. The system clock continues to operate. Bus clocks, if enabled, continue
to operate. Run regulation is maintained.

STOP

The core clock is gated off. System clocks to other masters and bus clocks are gated off after all
stop acknowledge signals from supporting peripherals are valid.

VLPR

The core, system, bus, and flash clock maximum frequencies are restricted in this mode. See the
Power Management chapter for details about the maximum allowable frequencies.

VLPW

The core clock is gated off. The system, bus, and flash clocks continue to operate, although their
maximum frequency is restricted. See the Power Management chapter for details on the maximum
allowable frequencies.

VLPS

The core clock is gated off. System clocks to other masters and bus clocks are gated off after all
stop acknowledge signals from supporting peripherals are valid.

LLS

The core clock is gated off. System clocks to other masters and bus clocks are gated off after all
stop acknowledge signals from supporting peripherals are valid. The MCU is placed in a low
leakage mode by reducing the voltage to internal logic. Internal logic states are retained.
Table continues on the next page...

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Chapter 13 System Mode Controller (SMC)

Table 13-1. Power modes (continued)
Mode

Description

VLLS3

The core clock is gated off. System clocks to other masters and bus clocks are gated off after all
stop acknowledge signals from supporting peripherals are valid. The MCU is placed in a low
leakage mode by powering down the internal logic. All system RAM contents are retained and I/O
states are held. Internal logic states are not retained.

VLLS1

The core clock is gated off. System clocks to other masters and bus clocks are gated off after all
stop acknowledge signals from supporting peripherals are valid. The MCU is placed in a low
leakage mode by powering down the internal logic and all system RAM. I/O states are held. Internal
logic states are not retained.

VLLS0

The core clock is gated off. System clocks to other masters and bus clocks are gated off after all
stop acknowledge signals from supporting peripherals are valid. The MCU is placed in a low
leakage mode by powering down the internal logic and all system RAM. I/O states are held. Internal
logic states are not retained. The 1kHz LPO clock is disabled and the power on reset (POR) circuit
can be optionally enabled using STOPCTRL[PORPO].

13.3 Memory map and register descriptions
Details follow about the registers related to the system mode controller.
Different SMC registers reset on different reset types. Each register's description provides
details. For more information about the types of reset on this chip, refer to the Reset
section details.
NOTE
The SMC registers can be written only in supervisor mode.
Write accesses in user mode are blocked and will result in a bus
error.
SMC memory map
Absolute
address
(hex)

Register name

Width
Access
(in bits)

Reset value

Section/
page

4007_E000

Power Mode Protection register (SMC_PMPROT)

8

R/W

00h

13.3.1/219

4007_E001

Power Mode Control register (SMC_PMCTRL)

8

R/W

00h

13.3.2/221

4007_E002

Stop Control Register (SMC_STOPCTRL)

8

R/W

03h

13.3.3/222

4007_E003

Power Mode Status register (SMC_PMSTAT)

8

R

01h

13.3.4/223

13.3.1 Power Mode Protection register (SMC_PMPROT)
This register provides protection for entry into any low-power run or stop mode. The
enabling of the low-power run or stop mode occurs by configuring the Power Mode
Control register (PMCTRL).
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Memory map and register descriptions

The PMPROT register can be written only once after any system reset.
If the MCU is configured for a disallowed or reserved power mode, the MCU remains in
its current power mode. For example, if the MCU is in normal RUN mode and AVLP is
0, an attempt to enter VLPR mode using PMCTRL[RUNM] is blocked and the RUNM
bits remain 00b, indicating the MCU is still in Normal Run mode.
NOTE
This register is reset on Chip Reset not VLLS and by reset
types that trigger Chip Reset not VLLS. It is unaffected by reset
types that do not trigger Chip Reset not VLLS. See the Reset
section details for more information.
Address: 4007_E000h base + 0h offset = 4007_E000h
Bit

Read
Write
Reset

7

6

5

0
0

0

4

AVLP

0

0

0

3

2

1

0

ALLS

0

AVLLS

0

0

0

0

0

SMC_PMPROT field descriptions
Field
7–6
Reserved
5
AVLP

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
Allow Very-Low-Power Modes
Provided the appropriate control bits are set up in PMCTRL, this write-once bit allows the MCU to enter
any very-low-power modes: VLPR, VLPW, and VLPS.
0
1

4
Reserved
3
ALLS

This field is reserved.
This read-only field is reserved and always has the value 0.
Allow Low-Leakage Stop Mode
This write once bit allows the MCU to enter any low-leakage stop mode (LLS), provided the appropriate
control bits are set up in PMCTRL.
0
1

2
Reserved
1
AVLLS

LLS is not allowed
LLS is allowed

This field is reserved.
This read-only field is reserved and always has the value 0.
Allow Very-Low-Leakage Stop Mode
Provided the appropriate control bits are set up in PMCTRL, this write once bit allows the MCU to enter
any very-low-leakage stop mode (VLLSx).
0
1

0
Reserved

VLPR, VLPW and VLPS are not allowed
VLPR, VLPW and VLPS are allowed

Any VLLSx mode is not allowed
Any VLLSx mode is allowed

This field is reserved.
This read-only field is reserved and always has the value 0.

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Chapter 13 System Mode Controller (SMC)

13.3.2 Power Mode Control register (SMC_PMCTRL)
The PMCTRL register controls entry into low-power run and stop modes, provided that
the selected power mode is allowed via an appropriate setting of the protection
(PMPROT) register.
NOTE
This register is reset on Chip POR not VLLS and by reset types
that trigger Chip POR not VLLS. It is unaffected by reset types
that do not trigger Chip POR not VLLS. See the Reset section
details for more information.
Address: 4007_E000h base + 1h offset = 4007_E001h
Bit

7

Read

0

6

RUNM

Write
Reset

5

0

0

0

4

3

0

STOPA

0

0

2

1

0

STOPM
0

0

0

SMC_PMCTRL field descriptions
Field
7
Reserved
6–5
RUNM

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
Run Mode Control
When written, causes entry into the selected run mode. Writes to this field are blocked if the protection
level has not been enabled using the PMPROT register. This field is cleared by hardware on any exit to
normal RUN mode.
NOTE: RUNM must be set to VLPR only when PMSTAT=RUN. After being written to VLPR, RUNM
should not be written back to RUN until PMSTAT=VLPR.
NOTE: RUNM must be set to RUN only when PMSTAT=VLPR. After being written to RUN, RUNM
should not be written back to VLPR until PMSTAT=RUN.
00
01
10
11

4
Reserved
3
STOPA

Normal Run mode (RUN)
Reserved
Very-Low-Power Run mode (VLPR)
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.
Stop Aborted
When set, this read-only status bit indicates an interrupt or reset occured during the previous stop mode
entry sequence, preventing the system from entering that mode. This bit is cleared by hardware at the
beginning of any stop mode entry sequence and is set if the sequence was aborted.
0
1

The previous stop mode entry was successsful.
The previous stop mode entry was aborted.
Table continues on the next page...

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Memory map and register descriptions

SMC_PMCTRL field descriptions (continued)
Field
2–0
STOPM

Description
Stop Mode Control
When written, controls entry into the selected stop mode when Sleep-Now or Sleep-On-Exit mode is
entered with SLEEPDEEP=1 . Writes to this field are blocked if the protection level has not been enabled
using the PMPROT register. After any system reset, this field is cleared by hardware on any successful
write to the PMPROT register.
NOTE: When set to VLLSx, the VLLSM bits in the STOPCTRL register is used to further select the
particular VLLS submode which will be entered.
NOTE: When set to STOP, the PSTOPO bits in the STOPCTRL register can be used to select a Partial
Stop mode if desired.
000
001
010
011
100
101
110
111

Normal Stop (STOP)
Reserved
Very-Low-Power Stop (VLPS)
Low-Leakage Stop (LLS)
Very-Low-Leakage Stop (VLLSx)
Reserved
Reseved
Reserved

13.3.3 Stop Control Register (SMC_STOPCTRL)
The STOPCTRL register provides various control bits allowing the user to fine tune
power consumption during the stop mode selected by the STOPM field.
NOTE
This register is reset on Chip POR not VLLS and by reset types
that trigger Chip POR not VLLS. It is unaffected by reset types
that do not trigger Chip POR not VLLS. See the Reset section
details for more information.
Address: 4007_E000h base + 2h offset = 4007_E002h
Bit

Read
Write
Reset

7

6

5

PSTOPO
0

0

4

3

PORPO

0

0

0

0

0

2

1

0

VLLSM
0

1

1

SMC_STOPCTRL field descriptions
Field
7–6
PSTOPO

Description
Partial Stop Option
These bits control whether a Partial Stop mode is entered when STOPM=STOP. When entering a Partial
Stop mode from RUN mode, the PMC, MCG and flash remain fully powered, allowing the device to
wakeup almost instantaneously at the expense of higher power consumption. In PSTOP2, only system
Table continues on the next page...

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Chapter 13 System Mode Controller (SMC)

SMC_STOPCTRL field descriptions (continued)
Field

Description
clocks are gated allowing peripherals running on bus clock to remain fully functional. In PSTOP1, both
system and bus clocks are gated.
00
01
10
11

5
PORPO

STOP - Normal Stop mode
PSTOP1 - Partial Stop with both system and bus clocks disabled
PSTOP2 - Partial Stop with system clock disabled and bus clock enabled
Reserved

POR Power Option
This bit controls whether the POR detect circuit is enabled in VLLS0 mode.
0
1

POR detect circuit is enabled in VLLS0
POR detect circuit is disabled in VLLS0

4
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

3
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

2–0
VLLSM

VLLS Mode Control.
This field controls which VLLS sub-mode to enter if STOPM=VLLS.
000
001
010
011
100
101
110
111

VLLS0
VLLS1
Reserved
VLLS3
Reserved
Reserved
Reserved
Reserved

13.3.4 Power Mode Status register (SMC_PMSTAT)
PMSTAT is a read-only, one-hot register which indicates the current power mode of the
system.
NOTE
This register is reset on Chip POR not VLLS and by reset types
that trigger Chip POR not VLLS. It is unaffected by reset types
that do not trigger Chip POR not VLLS. See the Reset section
details for more information.

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Functional description
Address: 4007_E000h base + 3h offset = 4007_E003h
Bit

7

Read

0

6

5

4

3

2

1

0

0

0

1

PMSTAT

Write
Reset

0

0

0

0

0

SMC_PMSTAT field descriptions
Field
7
Reserved
6–0
PMSTAT

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
NOTE: When debug is enabled, the PMSTAT will not update to STOP or VLPS
NOTE: When a PSTOP mode is enabled, the PMSTAT will not update to STOP or VLPS
000_0001
000_0010
000_0100
000_1000
001_0000
010_0000
100_0000

Current power mode is RUN
Current power mode is STOP
Current power mode is VLPR
Current power mode is VLPW
Current power mode is VLPS
Current power mode is LLS
Current power mode is VLLS

13.4 Functional description

13.4.1 Power mode transitions
The following figure shows the power mode state transitions available on the chip. Any
reset always brings the MCU back to the normal run state.

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Chapter 13 System Mode Controller (SMC)

Any RESET

VLPW

4

5

VLPR

WAIT

1
3

RUN

7

2

STOP

6

VLPS

10

8

VLLS
3, 2, 1, 0

LLS

9

11

Figure 13-5. Power mode state diagram

The following table defines triggers for the various state transitions shown in the previous
figure.
Table 13-7. Power mode transition triggers
Transition #

From

To

1

RUN

WAIT

Trigger conditions
Sleep-now or sleep-on-exit modes entered with SLEEPDEEP
clear, controlled in System Control Register in ARM core.
See note.1

WAIT

RUN

Interrupt or Reset

Table continues on the next page...

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Functional description

Table 13-7. Power mode transition triggers (continued)
Transition #

From

To

2

RUN

STOP

Trigger conditions
PMCTRL[RUNM]=00, PMCTRL[STOPM]=0002
Sleep-now or sleep-on-exit modes entered with SLEEPDEEP
set, which is controlled in System Control Register in ARM
core.
See note.1

3

STOP

RUN

Interrupt or Reset

RUN

VLPR

The core, system, bus and flash clock frequencies are
restricted in this mode. See the Power Management chapter
for the maximum allowable frequencies.
Set PMPROT[AVLP]=1, PMCTRL[RUNM]=10.

VLPR

RUN

Set PMCTRL[RUNM]=00 or
Reset.

4

VLPR

VLPW

Sleep-now or sleep-on-exit modes entered with SLEEPDEEP
clear, which is controlled in System Control Register in ARM
core.
See note.1

VLPW

VLPR

Interrupt

5

VLPW

RUN

Reset

6

VLPR

VLPS

PMCTRL[STOPM]=0003 or 010,
Sleep-now or sleep-on-exit modes entered with SLEEPDEEP
set, which is controlled in System Control Register in ARM
core.
See note.1

VLPS

VLPR

Interrupt
NOTE: If VLPS was entered directly from RUN, hardware
will not allow this transition and will force exit back to
RUN

7

RUN

VLPS

PMPROT[AVLP]=1, PMCTRL[STOPM]=010,
Sleep-now or sleep-on-exit modes entered with SLEEPDEEP
set, which is controlled in System Control Register in ARM
core.
See note.1

VLPS

RUN

Interrupt and VLPS mode was entered directly from RUN or
Reset

8

9

RUN

VLLSx

VLLSx

RUN

VLPR

VLLSx

PMPROT[AVLLS]=1, PMCTRL[STOPM]=100,
STOPCTRL[VLLSM]=x (VLLSx), Sleep-now or sleep-on-exit
modes entered with SLEEPDEEP set, which is controlled in
System Control Register in ARM core.
Wakeup from enabled LLWU input source or RESET pin
PMPROT[AVLLS]=1, PMCTRL[STOPM]=100,
STOPCTRL[VLLSM]=x (VLLSx), Sleep-now or sleep-on-exit
modes entered with SLEEPDEEP set, which is controlled in
System Control Register in ARM core.

Table continues on the next page...

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Chapter 13 System Mode Controller (SMC)

Table 13-7. Power mode transition triggers (continued)
Transition #

From

To

10

RUN

LLS

PMPROT[ALLS]=1, PMCTRL[STOPM]=011, Sleep-now or
sleep-on-exit modes entered with SLEEPDEEP set, which is
controlled in System Control Register in ARM core.

LLS

RUN

Wakeup from enabled LLWU input source or RESET pin.

VLPR

LLS

PMPROT[ALLS]=1, PMCTRL[STOPM]=011, Sleep-now or
sleep-on-exit modes entered with SLEEPDEEP set, which is
controlled in System Control Register in ARM core.

11

Trigger conditions

1. If debug is enabled, the core clock remains to support debug.
2. If PMCTRL[STOPM]=000 and STOPCTRL[PSTOPO]=01 or 10, then only a Partial Stop mode is entered instead of STOP
3. If PMCTRL[STOPM]=000 and STOPCTRL[PSTOPO]=00, then VLPS mode is entered instead of STOP. If
PMCTRL[STOPM]=000 and STOPCTRL[PSTOPO]=01 or 10, then only a Partial Stop mode is entered instead of VLPS

13.4.2 Power mode entry/exit sequencing
When entering or exiting low-power modes, the system must conform to an orderly
sequence to manage transitions safely. The SMC manages the system's entry into and exit
from all power modes. The following diagram illustrates the connections of the SMC
with other system components in the chip that are necessary to sequence the system
through all power modes.

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Functional description

Reset
Control
Module

LowLeakage
Wakeup

CPU

(RCM)

(LLWU)

Stop/Wait

LP exit
LP exit

System
Mode
Controller

CCM low power bus

(SMC)

Clock
Control
Module

Bus masters low power bus (non-CPU)
Bus slaves low power bus

(CCM)

PMC low power bus
MCG enable

System
Power
(PMC)

System
Clocks
(MCG)

Flash low power bus

Flash
Memory
Module

Figure 13-6. Low-power system components and connections

13.4.2.1 Stop mode entry sequence
Entry into a low-power stop mode (Stop, VLPS, LLS, VLLSx) is initiated by CPU
execution of the WFI instruction. After the instruction is executed, the following
sequence occurs:
1. The CPU clock is gated off immediately.
2. Requests are made to all non-CPU bus masters to enter Stop mode.
3. After all masters have acknowledged they are ready to enter Stop mode, requests are
made to all bus slaves to enter Stop mode.
4. After all slaves have acknowledged they are ready to enter Stop mode, all system and
bus clocks are gated off.
5. Clock generators are disabled in the MCG.
6. The on-chip regulator in the PMC and internal power switches are configured to
meet the power consumption goals for the targeted low-power mode.
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Chapter 13 System Mode Controller (SMC)

13.4.2.2 Stop mode exit sequence
Exit from a low-power stop mode is initiated either by a reset or an interrupt event. The
following sequence then executes to restore the system to a run mode (RUN or VLPR):
1. The on-chip regulator in the PMC and internal power switches are restored.
2. Clock generators are enabled in the MCG.
3. System and bus clocks are enabled to all masters and slaves.
4. The CPU clock is enabled and the CPU begins servicing the reset or interrupt that
initiated the exit from the low-power stop mode.

13.4.2.3 Aborted stop mode entry
If an interrupt or a reset occurs during a stop entry sequence, the SMC can abort the
transition early and return to RUN mode without completely entering the stop mode. An
aborted entry is possible only if the reset or interrupt occurs before the PMC begins the
transition to stop mode regulation. After this point, the interrupt or reset is ignored until
the PMC has completed its transition to stop mode regulation. When an aborted stop
mode entry sequence occurs, the SMC's PMCTRL[STOPA] is set to 1.

13.4.2.4 Transition to wait modes
For wait modes (WAIT and VLPW), the CPU clock is gated off while all other clocking
continues, as in RUN and VLPR mode operation. Some modules that support stop-inwait functionality have their clocks disabled in these configurations.

13.4.2.5 Transition from stop modes to Debug mode
The debugger module supports a transition from STOP, WAIT, VLPS, and VLPW back
to a Halted state when the debugger has been enabled, that is, ENBDM is 1. As part of
this transition, system clocking is re-established and is equivalent to the normal RUN and
VLPR mode clocking configuration.

13.4.3 Run modes
The device contains two different run modes:
• Run
• Very Low-Power Run (VLPR)
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Functional description

13.4.3.1 RUN mode
This is the normal operating mode for the device.
This mode is selected after any reset. When the ARM processor exits reset, it sets up the
stack, program counter (PC), and link register (LR):
• The processor reads the start SP (SP_main) from vector-table offset 0x000
• The processor reads the start PC from vector-table offset 0x004
• LR is set to 0xFFFF_FFFF.
To reduce power in this mode, disable the clocks to unused modules using their
corresponding clock gating control bits in the SIM's registers.

13.4.3.2 Very-Low Power Run (VLPR) mode
In VLPR mode, the on-chip voltage regulator is put into a stop mode regulation state. In
this state, the regulator is designed to supply enough current to the MCU over a reduced
frequency. To further reduce power in this mode, disable the clocks to unused modules
using their corresponding clock gating control bits in the SIM's registers.
Before entering this mode, the following conditions must be met:
• The MCG must be configured in a mode which is supported during VLPR. See the
Power Management details for information about these MCG modes.
• All clock monitors in the MCG must be disabled.
• The maximum frequencies of the system, bus, flash, and core are restricted. See the
Power Management details about which frequencies are supported.
• Mode protection must be set to allow VLP modes, that is, PMPROT[AVLP] is 1.
• PMCTRL[RUNM] is set to 10b to enter VLPR.
• Flash programming/erasing is not allowed.
NOTE
Do not change the clock frequency while in VLPR mode,
because the regulator is slow responding and cannot manage
fast load transitions. In addition, do not modify the clock source
in the MCG module, the module clock enables in the SIM, or
any clock divider registers.

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Chapter 13 System Mode Controller (SMC)

To reenter Normal Run mode, clear RUNM. The PMSTAT register is a read-only status
register that can be used to determine when the system has completed an exit to RUN
mode. When PMSTAT=RUN, the system is in run regulation and the MCU can run at
full speed in any clock mode. If a higher execution frequency is desired, poll the
PMSTAT register until it is set to RUN when returning from VLPR mode.
Any reset always causes an exit from VLPR and returns the device to RUN mode after
the MCU exits its reset flow.

13.4.4 Wait modes
This device contains two different wait modes:
• Wait
• Very-Low Power Wait (VLPW)

13.4.4.1 WAIT mode
WAIT mode is entered when the ARM core enters the Sleep-Now or Sleep-On-Exit
modes while SLEEDEEP is cleared. The ARM CPU enters a low-power state in which it
is not clocked, but peripherals continue to be clocked provided they are enabled. Clock
gating to the peripheral is enabled via the SIM..
When an interrupt request occurs, the CPU exits WAIT mode and resumes processing in
RUN mode, beginning with the stacking operations leading to the interrupt service
routine.
A system reset will cause an exit from WAIT mode, returning the device to normal RUN
mode.

13.4.4.2 Very-Low-Power Wait (VLPW) mode
VLPW is entered by the entering the Sleep-Now or Sleep-On-Exit mode while
SLEEPDEEP is cleared and the MCU is in VLPR mode.
In VLPW, the on-chip voltage regulator remains in its stop regulation state. In this state,
the regulator is designed to supply enough current to the MCU over a reduced frequency.
To further reduce power in this mode, disable the clocks to unused modules by clearing
the peripherals' corresponding clock gating control bits in the SIM.
VLPR mode restrictions also apply to VLPW.
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Functional description

When an interrupt from VLPW occurs, the device returns to VLPR mode to execute the
interrupt service routine.
A system reset will cause an exit from VLPW mode, returning the device to normal RUN
mode.

13.4.5 Stop modes
This device contains a variety of stop modes to meet your application needs. The stop
modes range from:
• a stopped CPU, with all I/O, logic, and memory states retained, and certain
asynchronous mode peripherals operating
to:
• a powered down CPU, with only I/O and a small register file retained, very few
asynchronous mode peripherals operating, while the remainder of the MCU is
powered down.
The choice of stop mode depends upon the user's application, and how power usage and
state retention versus functional needs may be traded off.
The various stop modes are selected by setting the appropriate fields in PMPROT and
PMCTRL. The selected stop mode mode is entered during the sleep-now or sleep-on-exit
entry with the SLEEPDEEP bit set in the System Control Register in the ARM core.
The available stop modes are:
•
•
•
•

Normal Stop (STOP)
Very-Low Power Stop (VLPS)
Low-Leakage Stop (LLS)
Very-Low-Leakage Stop (VLLSx)

13.4.5.1 STOP mode
STOP mode is entered via the sleep-now or sleep-on-exit with the SLEEPDEEP bit set in
the System Control Register in the ARM core.
The MCG module can be configured to leave the reference clocks running.

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Chapter 13 System Mode Controller (SMC)

A module capable of providing an asynchronous interrupt to the device takes the device
out of STOP mode and returns the device to normal RUN mode. Refer to the device's
Power Management chapter for peripheral, I/O, and memory operation in STOP mode.
When an interrupt request occurs, the CPU exits STOP mode and resumes processing,
beginning with the stacking operations leading to the interrupt service routine.
A system reset will cause an exit from STOP mode, returning the device to normal RUN
mode via an MCU reset.

13.4.5.2 Very-Low-Power Stop (VLPS) mode
VLPS mode can be entered in one of two ways:
• Entry into stop via the sleep-now or sleep-on-exit with the SLEEPDEEP bit set in the
System Control Register in the ARM core while the MCU is in VLPR mode and
STOPM=010 or 000 in the PMCTRL register.
• Entry into stop via the sleep-now or sleep-on-exit with the SLEEPDEEP bit set in the
System Control Register in the ARM core while the MCU is in normal RUN mode
and STOPM=010 in the PMCTRL register. When VLPS is entered directly from
RUN mode, exit to VLPR is disabled by hardware and the system will always exit
back to RUN.
In VLPS, the on-chip voltage regulator remains in its stop regulation state as in VLPR.
A module capable of providing an asynchronous interrupt to the device takes the device
out of VLPS and returns the device to VLPR mode.
A system reset will also cause a VLPS exit, returning the device to normal RUN mode.

13.4.5.3 Low-Leakage Stop (LLS) mode
Low-Leakage Stop (LLS) mode can be entered from normal RUN or VLPR modes.
The MCU enters LLS mode if:
• In Sleep-Now or Sleep-On-Exit mode, SLEEPDEEP is set in the System Control
Register in the ARM core, and
• The device is configured as shown in Table 13-7.
In LLS, the on-chip voltage regulator is in stop regulation. Most of the peripherals are put
in a state-retention mode that does not allow them to operate while in LLS.

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Functional description

Before entering LLS mode, the user should configure the low-leakage wakeup (LLWU)
module to enable the desired wakeup sources. The available wakeup sources in LLS are
detailed in the chip configuration details for this device.
After wakeup from LLS, the device returns to normal RUN mode with a pending LLWU
module interrupt. In the LLWU interrupt service routine (ISR), the user can poll the
LLWU module wakeup flags to determine the source of the wakeup.
NOTE
The LLWU interrupt must not be masked by the interrupt
controller to avoid a scenario where the system does not fully
exit stop mode on an LLS recovery.
An asserted RESET pin will cause an exit from LLS mode, returning the device to
normal RUN mode. When LLS is exiting via the RESET pin, the PIN and WAKEUP bits
are set in the SRS0 register of the reset control module (RCM).

13.4.5.4 Very-Low-Leakage Stop (VLLSx) modes
This device contains these very low leakage modes:
• VLLS3
• VLLS1
• VLLS0
VLLSx is often used in this document to refer to all of these modes.
All VLLSx modes can be entered from normal RUN or VLPR modes.
The MCU enters the configured VLLS mode if:
• In Sleep-Now or Sleep-On-Exit mode, the SLEEPDEEP bit is set in the System
Control Register in the ARM core, and
• The device is configured as shown in Table 13-7.
In VLLS, the on-chip voltage regulator is in its stop-regulation state while most digital
logic is powered off.
Before entering VLLS mode, the user should configure the low-leakage wakeup (LLWU)
module to enable the desired wakeup sources. The available wakeup sources in VLLS are
detailed in the chip configuration details for this device.
After wakeup from VLLS, the device returns to normal RUN mode with a pending
LLWU interrupt. In the LLWU interrupt service routine (ISR), the user can poll the
LLWU module wakeup flags to determine the source of the wakeup.

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Chapter 13 System Mode Controller (SMC)

When entering VLLS, each I/O pin is latched as configured before executing VLLS.
Because all digital logic in the MCU is powered off, all port and peripheral data is lost
during VLLS. This information must be restored before the ACKISO bit in the PMC is
set.
An asserted RESET pin will cause an exit from any VLLS mode, returning the device to
normal RUN mode. When exiting VLLS via the RESET pin, the PIN and WAKEUP bits
are set in the SRS0 register of the reset control module (RCM).

13.4.6 Debug in low power modes
When the MCU is secure, the device disables/limits debugger operation. When the MCU
is unsecure, the ARM debugger can assert two power-up request signals:
• System power up, via SYSPWR in the Debug Port Control/Stat register
• Debug power up, via CDBGPWRUPREQ in the Debug Port Control/Stat register
When asserted while in RUN, WAIT, VLPR, or VLPW, the mode controller drives a
corresponding acknowledge for each signal, that is, both CDBGPWRUPACK and
CSYSPWRUPACK. When both requests are asserted, the mode controller handles
attempts to enter STOP and VLPS by entering an emulated stop state. In this emulated
stop state:
•
•
•
•
•

the regulator is in run regulation,
the MCG-generated clock source is enabled,
all system clocks, except the core clock, are disabled,
the debug module has access to core registers, and
access to the on-chip peripherals is blocked.

No debug is available while the MCU is in LLS or VLLS modes. LLS is a state-retention
mode and all debug operation can continue after waking from LLS, even in cases where
system wakeup is due to a system reset event.
Entering into a VLLS mode causes all of the debug controls and settings to be powered
off. To give time to the debugger to sync with the MCU, the MDM AP Control Register
includes a Very-Low-Leakage Debug Request (VLLDBGREQ) bit that is set to configure
the Reset Controller logic to hold the system in reset after the next recovery from a VLLS
mode. This bit allows the debugger time to reinitialize the debug module before the
debug session continues.

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Functional description

The MDM AP Control Register also includes a Very Low Leakage Debug Acknowledge
(VLLDBGACK) bit that is set to release the ARM core being held in reset following a
VLLS recovery. The debugger reinitializes all debug IP, and then asserts the
VLLDBGACK control bit to allow the RCM to release the ARM core from reset and
allow CPU operation to begin.
The VLLDBGACK bit is cleared by the debugger (or can be left set as is) or clears
automatically due to the reset generated as part of the next VLLS recovery.

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Chapter 14
Power Management Controller (PMC)
14.1 Introduction
NOTE
For the chip-specific implementation details of this module's
instances see the chip configuration information.
The power management controller (PMC) contains the internal voltage regulator, power
on reset (POR), and low voltage detect system.

14.2 Features
The PMC features include:
• Internal voltage regulator
• Active POR providing brown-out detect
• Low-voltage detect supporting two low-voltage trip points with four warning levels
per trip point

14.3 Low-voltage detect (LVD) system
This device includes a system to guard against low-voltage conditions. This protects
memory contents and controls MCU system states during supply voltage variations. The
system is comprised of a power-on reset (POR) circuit and a LVD circuit with a userselectable trip voltage: high (VLVDH) or low (VLVDL). The trip voltage is selected by the
LVDSC1[LVDV] bits. The LVD is disabled upon entering VLPx, LLS, and VLLSx
modes.
Two flags are available to indicate the status of the low-voltage detect system:

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Low-voltage detect (LVD) system

• The low voltage detect flag (LVDF) operates in a level sensitive manner. The LVDF
bit is set when the supply voltage falls below the selected trip point (VLVD). The
LVDF bit is cleared by writing one to the LVDACK bit, but only if the internal
supply has returned above the trip point; otherwise, the LVDF bit remains set.
• The low voltage warning flag (LVWF) operates in a level sensitive manner. The
LVWF bit is set when the supply voltage falls below the selected monitor trip point
(VLVW). The LVWF bit is cleared by writing one to the LVWACK bit, but only if
the internal supply has returned above the trip point; otherwise, the LVWF bit
remains set.

14.3.1 LVD reset operation
By setting the LVDRE bit, the LVD generates a reset upon detection of a low voltage
condition. The low voltage detection threshold is determined by the LVDV bits. After an
LVD reset occurs, the LVD system holds the MCU in reset until the supply voltage rises
above this threshold. The LVD bit in the SRS register is set following an LVD or poweron reset.

14.3.2 LVD interrupt operation
By configuring the LVD circuit for interrupt operation (LVDIE set and LVDRE clear),
LVDSC1[LVDF] is set and an LVD interrupt request occurs upon detection of a low
voltage condition. The LVDF bit is cleared by writing one to the LVDSC1[LVDACK]
bit.

14.3.3 Low-voltage warning (LVW) interrupt operation
The LVD system contains a low-voltage warning flag (LVWF) to indicate that the supply
voltage is approaching, but is above, the LVD voltage. The LVW also has an interrupt,
which is enabled by setting the LVDSC2[LVWIE] bit. If enabled, an LVW interrupt
request occurs when the LVWF is set. LVWF is cleared by writing one to the
LVDSC2[LVWACK] bit.
The LVDSC2[LVWV] bits select one of four trip voltages:
• Highest: VLVW4
• Two mid-levels: VLVW3 and VLVW2
• Lowest: VLVW1

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Chapter 14 Power Management Controller (PMC)

14.4 I/O retention
When in LLS mode, the I/O pins are held in their input or output state. Upon wakeup, the
PMC is re-enabled, goes through a power up sequence to full regulation, and releases the
logic from state retention mode. The I/O are released immediately after a wakeup or reset
event. In the case of LLS exit via a RESET pin, the I/O default to their reset state.
When in VLLS modes, the I/O states are held on a wakeup event (with the exception of
wakeup by reset event) until the wakeup has been acknowledged via a write to the
ACKISO bit. In the case of VLLS exit via a RESET pin, the I/O are released and default
to their reset state. In this case, no write to the ACKISO is needed.

14.5 Memory map and register descriptions
PMC register details follow.
NOTE
Different portions of PMC registers are reset only by particular
reset types. Each register's description provides details. For
more information about the types of reset on this chip, refer to
the Reset section details.
The PMC registers can be written only in supervisor mode.
Write accesses in user mode are blocked and will result in a bus
error.
PMC memory map
Absolute
address
(hex)

Register name

Width
Access
(in bits)

Reset value

Section/
page

4007_D000

Low Voltage Detect Status And Control 1 register
(PMC_LVDSC1)

8

R/W

10h

14.5.1/240

4007_D001

Low Voltage Detect Status And Control 2 register
(PMC_LVDSC2)

8

R/W

00h

14.5.2/241

4007_D002

Regulator Status And Control register (PMC_REGSC)

8

R/W

04h

14.5.3/242

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Memory map and register descriptions

14.5.1 Low Voltage Detect Status And Control 1 register
(PMC_LVDSC1)
This register contains status and control bits to support the low voltage detect function.
This register should be written during the reset initialization program to set the desired
controls even if the desired settings are the same as the reset settings.
While the device is in the very low power or low leakage modes, the LVD system is
disabled regardless of LVDSC1 settings. To protect systems that must have LVD always
on, configure the SMC's power mode protection register (PMPROT) to disallow any very
low power or low leakage modes from being enabled.
See the device's data sheet for the exact LVD trip voltages.
NOTE
The LVDV bits are reset solely on a POR Only event. The
register's other bits are reset on Chip Reset Not VLLS. For
more information about these reset types, refer to the Reset
section details.
Address: 4007_D000h base + 0h offset = 4007_D000h
Bit

Read

7

6

LVDF

0

Write
Reset

LVDACK
0

0

5

4

3

LVDIE

LVDRE

0

1

2

1

0

0

0

LVDV
0

0

0

PMC_LVDSC1 field descriptions
Field
7
LVDF

Description
Low-Voltage Detect Flag
This read-only status bit indicates a low-voltage detect event.
0
1

6
LVDACK

5
LVDIE

Low-voltage event not detected
Low-voltage event detected

Low-Voltage Detect Acknowledge
This write-only bit is used to acknowledge low voltage detection errors. Write 1 to clear LVDF. Reads
always return 0.
Low-Voltage Detect Interrupt Enable
Enables hardware interrupt requests for LVDF.
0
1

Hardware interrupt disabled (use polling)
Request a hardware interrupt when LVDF = 1
Table continues on the next page...

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Chapter 14 Power Management Controller (PMC)

PMC_LVDSC1 field descriptions (continued)
Field
4
LVDRE

Description
Low-Voltage Detect Reset Enable
This write-once bit enables LVDF events to generate a hardware reset. Additional writes are ignored.
0
1

3–2
Reserved
1–0
LVDV

LVDF does not generate hardware resets
Force an MCU reset when LVDF = 1

This field is reserved.
This read-only field is reserved and always has the value 0.
Low-Voltage Detect Voltage Select
Selects the LVD trip point voltage (V LVD ).
00
01
10
11

Low trip point selected (V LVD = V LVDL )
High trip point selected (V LVD = V LVDH )
Reserved
Reserved

14.5.2 Low Voltage Detect Status And Control 2 register
(PMC_LVDSC2)
This register contains status and control bits to support the low voltage warning function.
While the device is in the very low power or low leakage modes, the LVD system is
disabled regardless of LVDSC2 settings.
See the device's data sheet for the exact LVD trip voltages.
NOTE
The LVW trip voltages depend on LVWV and LVDV bits.
NOTE
The LVWV bits are reset solely on a POR Only event. The
register's other bits are reset on Chip Reset Not VLLS. For
more information about these reset types, refer to the Reset
section details.
Address: 4007_D000h base + 1h offset = 4007_D001h
Bit

Read

7

6

LVWF

0

Write
Reset

LVWACK
0

0

5

4

2

1

0

LVWIE
0

3

0

0

0

LVWV
0

0

0

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Memory map and register descriptions

PMC_LVDSC2 field descriptions
Field
7
LVWF

Description
Low-Voltage Warning Flag
This read-only status bit indicates a low-voltage warning event. LVWF is set when VSupply transitions below
the trip point, or after reset and VSupply is already below VLVW. LVWF bit may be 1 after power on reset,
therefore, to use LVW interrupt function, before enabling LVWIE, LVWF must be cleared by writing
LVWACK first.
0
1

6
LVWACK

5
LVWIE

Low-Voltage Warning Acknowledge
This write-only bit is used to acknowledge low voltage warning errors. Write 1 to clear LVWF. Reads
always return 0.
Low-Voltage Warning Interrupt Enable
Enables hardware interrupt requests for LVWF.
0
1

4–2
Reserved
1–0
LVWV

Low-voltage warning event not detected
Low-voltage warning event detected

Hardware interrupt disabled (use polling)
Request a hardware interrupt when LVWF = 1

This field is reserved.
This read-only field is reserved and always has the value 0.
Low-Voltage Warning Voltage Select
Selects the LVW trip point voltage (VLVW). The actual voltage for the warning depends on LVDSC1[LVDV].
00
01
10
11

Low trip point selected (VLVW = VLVW1)
Mid 1 trip point selected (VLVW = VLVW2)
Mid 2 trip point selected (VLVW = VLVW3)
High trip point selected (VLVW = VLVW4)

14.5.3 Regulator Status And Control register (PMC_REGSC)
The PMC contains an internal voltage regulator. The voltage regulator design uses a
bandgap reference that is also available through a buffer as input to certain internal
peripherals, such as the CMP and ADC. The internal regulator provides a status bit
(REGONS) indicating the regulator is in run regulation.
NOTE
This register is reset on Chip Reset Not VLLS and by reset
types that trigger Chip Reset not VLLS. See the Reset section
for more information.

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Chapter 14 Power Management Controller (PMC)
Address: 4007_D000h base + 2h offset = 4007_D002h
Bit

7

Read

6

5

0

Write
Reset

0

4

Reserved

BGEN

0

0

0

3

2

ACKISO

REGONS

w1c
0

1

1

0

Reserved

BGBE

0

0

PMC_REGSC field descriptions
Field

Description

7–6
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

5
Reserved

This field is reserved.

4
BGEN

Bandgap Enable In VLPx Operation
BGEN controls whether the bandgap is enabled in lower power modes of operation (VLPx, LLS, and
VLLSx). When on-chip peripherals require the bandgap voltage reference in low power modes of
operation, set BGEN to continue to enable the bandgap operation.
NOTE: When the bandgap voltage reference is not needed in low power modes, clear BGEN to avoid
excess power consumption.
0
1

3
ACKISO

Bandgap voltage reference is disabled in VLPx , LLS , and VLLSx modes
Bandgap voltage reference is enabled in VLPx , LLS , and VLLSx modes

Acknowledge Isolation
Reading this bit indicates whether certain peripherals and the I/O pads are in a latched state as a result of
having been in a VLLS mode. Writing one to this bit when it is set releases the I/O pads and certain
peripherals to their normal run mode state.
NOTE: After recovering from a VLLS mode, user should restore chip configuration before clearing
ACKISO. In particular, pin configuration for enabled LLWU wakeup pins should be restored to
avoid any LLWU flag from being falsely set when ACKISO is cleared.
0
1

2
REGONS

Regulator In Run Regulation Status
This read-only bit provides the current status of the internal voltage regulator.
0
1

1
Reserved

Peripherals and I/O pads are in normal run state
Certain peripherals and I/O pads are in an isolated and latched state

Regulator is in stop regulation or in transition to/from it
Regulator is in run regulation

This field is reserved.
NOTE: This reserved bit must remain cleared (set to 0).

0
BGBE

Bandgap Buffer Enable
Enables the bandgap buffer.
0
1

Bandgap buffer not enabled
Bandgap buffer enabled

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Chapter 15
Low-Leakage Wakeup Unit (LLWU)
15.1 Introduction
NOTE
For the chip-specific implementation details of this module's
instances see the chip configuration information.
The LLWU module allows the user to select up to 16 external pin sources and up to 8
internal modules as a wakeup source from low-leakage power modes. The input sources
are described in the device's chip configuration details. Each of the available wakeup
sources can be individually enabled.
The LLWU module also includes two optional digital pin filters for the external wakeup
pins.

15.1.1 Features
The LLWU module features include:
• Support for up to 16 external input pins and up to 8 internal modules with individual
enable bits
• Input sources may be external pins or from internal peripherals capable of running in
LLS or VLLS. See the chip configuration information for wakeup input sources for
this device.
• External pin wakeup inputs, each of which is programmable as falling-edge, risingedge, or any change
• Wakeup inputs that are activated if enabled after MCU enters a low-leakage power
mode
• Optional digital filters provided to qualify an external pin detect. When entering
VLLS0, the filters are disabled and bypassed.

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Introduction

15.1.2 Modes of operation
The LLWU module becomes functional on entry into a low-leakage power mode. After
recovery from LLS, the LLWU is immediately disabled. After recovery from VLLS, the
LLWU continues to detect wakeup events until the user has acknowledged the wakeup
via a write to the PMC_REGSC[ACKISO] bit.

15.1.2.1 LLS mode
The LLWU module provides up to 16 external wakeup inputs and up to 8 internal module
wakeup inputs.
Wakeup events due to external wakeup inputs and internal module wakeup inputs result
in an interrupt flow when exiting LLS.
NOTE
The LLWU interrupt must not be masked by the interrupt
controller to avoid a scenario where the system does not fully
exit Stop mode on an LLS recovery.

15.1.2.2 VLLS modes
The LLWU module provides up to 16 external wakeup inputs and up to 8 internal module
wakeup inputs. All wakeup events result in VLLS exit via a reset flow.

15.1.2.3 Non-low leakage modes
The LLWU is not active in all non-low leakage modes where detection and control logic
are in a static state. The LLWU registers are accessible in non-low leakage modes and are
available for configuring and reading status when bus transactions are possible.
When the wakeup pin filters are enabled, filter operation begins immediately. If a low
leakage mode is entered within 5 LPO clock cycles of an active edge, the edge event will
be detected by the LLWU.

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Chapter 15 Low-Leakage Wakeup Unit (LLWU)

15.1.2.4 Debug mode
When the chip is in Debug mode and then enters LLS or a VLLSx mode, no debug logic
works in the fully-functional low-leakage mode. Upon an exit from the LLS or VLLSx
mode, the LLWU becomes inactive.

15.1.3 Block diagram
The following figure is the block diagram for the LLWU module.
enter low leakge mode

WUME7

Module7 interrupt flag
(LLWU_M7IF)

Module0 interrupt flag
(LLWU_M0IF)

Interrupt module
flag detect

LLWU_MWUF7 occurred
Internal
module
sources

Interrupt module
flag detect

FILT1[FILTSEL]

LLWU_MWUF0 occurred

WUME0
LPO

LLWU_P15
Synchronizer
LLWU_P0

Pin filter 1

LPO

Synchronizer

Pin filter 2

FILT1[FILTE]

Edge
detect

Pin filter 1
wakeup
occurred

LLWU
controller

FILT2[FILTE]

Edge
detect

exit low leakge mode

Pin filter 2
wakeup
occurred

interrupt flow
reset flow

WUPE15
2
FILT2[FILTSEL]
Edge
detect

Edge
detect

LLWU_P15
wakeup occurred

LLWU_P0
wakeup occurred

External
pin sources

2
WUPE0

Figure 15-1. LLWU block diagram

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15.2 LLWU signal descriptions
The signal properties of LLWU are shown in the following table. The external wakeup
input pins can be enabled to detect either rising-edge, falling-edge, or on any change.
Table 15-1. LLWU signal descriptions
Signal
LLWU_Pn

Description

I/O

Wakeup inputs (n = 0-15)

I

15.3 Memory map/register definition
The LLWU includes the following registers:
• Five 8-bit wakeup source enable registers
• Enable external pin input sources
• Enable internal peripheral sources
• Three 8-bit wakeup flag registers
• Indication of wakeup source that caused exit from a low-leakage power mode
includes external pin or internal module interrupt
• Two 8-bit wakeup pin filter enable registers
NOTE
The LLWU registers can be written only in supervisor mode.
Write accesses in user mode are blocked and will result in a bus
error.
All LLWU registers are reset by Chip Reset not VLLS and by
reset types that trigger Chip Reset not VLLS. Each register's
displayed reset value represents this subset of reset types.
LLWU registers are unaffected by reset types that do not trigger
Chip Reset not VLLS. For more information about the types of
reset on this chip, refer to the Introduction details.

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Chapter 15 Low-Leakage Wakeup Unit (LLWU)

LLWU memory map
Absolute
address
(hex)

Width
Access
(in bits)

Register name

Reset value

Section/
page

4007_C000

LLWU Pin Enable 1 register (LLWU_PE1)

8

R/W

00h

15.3.1/249

4007_C001

LLWU Pin Enable 2 register (LLWU_PE2)

8

R/W

00h

15.3.2/250

4007_C002

LLWU Pin Enable 3 register (LLWU_PE3)

8

R/W

00h

15.3.3/251

4007_C003

LLWU Pin Enable 4 register (LLWU_PE4)

8

R/W

00h

15.3.4/252

4007_C004

LLWU Module Enable register (LLWU_ME)

8

R/W

00h

15.3.5/253

4007_C005

LLWU Flag 1 register (LLWU_F1)

8

R/W

00h

15.3.6/255

4007_C006

LLWU Flag 2 register (LLWU_F2)

8

R/W

00h

15.3.7/257

4007_C007

LLWU Flag 3 register (LLWU_F3)

8

R

00h

15.3.8/258

4007_C008

LLWU Pin Filter 1 register (LLWU_FILT1)

8

R/W

00h

15.3.9/260

4007_C009

LLWU Pin Filter 2 register (LLWU_FILT2)

8

R/W

00h

15.3.10/261

15.3.1 LLWU Pin Enable 1 register (LLWU_PE1)
LLWU_PE1 contains the field to enable and select the edge detect type for the external
wakeup input pins LLWU_P3-LLWU_P0.
NOTE
This register is reset on Chip Reset not VLLS and by reset
types that trigger Chip Reset not VLLS. It is unaffected by reset
types that do not trigger Chip Reset not VLLS. See the
Introduction details for more information.
Address: 4007_C000h base + 0h offset = 4007_C000h
Bit

Read
Write
Reset

7

6

5

WUPE3
0

4

3

WUPE2
0

0

2

1

WUPE1
0

0

0

WUPE0
0

0

0

LLWU_PE1 field descriptions
Field
7–6
WUPE3

Description
Wakeup Pin Enable For LLWU_P3
Enables and configures the edge detection for the wakeup pin.
00
01
10
11

5–4
WUPE2

External input pin disabled as wakeup input
External input pin enabled with rising edge detection
External input pin enabled with falling edge detection
External input pin enabled with any change detection

Wakeup Pin Enable For LLWU_P2
Enables and configures the edge detection for the wakeup pin.
Table continues on the next page...

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LLWU_PE1 field descriptions (continued)
Field

Description
00
01
10
11

3–2
WUPE1

Wakeup Pin Enable For LLWU_P1
Enables and configures the edge detection for the wakeup pin.
00
01
10
11

1–0
WUPE0

External input pin disabled as wakeup input
External input pin enabled with rising edge detection
External input pin enabled with falling edge detection
External input pin enabled with any change detection

External input pin disabled as wakeup input
External input pin enabled with rising edge detection
External input pin enabled with falling edge detection
External input pin enabled with any change detection

Wakeup Pin Enable For LLWU_P0
Enables and configures the edge detection for the wakeup pin.
00
01
10
11

External input pin disabled as wakeup input
External input pin enabled with rising edge detection
External input pin enabled with falling edge detection
External input pin enabled with any change detection

15.3.2 LLWU Pin Enable 2 register (LLWU_PE2)
LLWU_PE2 contains the field to enable and select the edge detect type for the external
wakeup input pins LLWU_P7-LLWU_P4.
NOTE
This register is reset on Chip Reset not VLLS and by reset
types that trigger Chip Reset not VLLS. It is unaffected by reset
types that do not trigger Chip Reset not VLLS. See the
Introduction details for more information.
Address: 4007_C000h base + 1h offset = 4007_C001h
Bit

Read
Write
Reset

7

6

5

WUPE7
0

4

3

WUPE6
0

0

2

1

WUPE5
0

0

0

WUPE4
0

0

0

LLWU_PE2 field descriptions
Field
7–6
WUPE7

Description
Wakeup Pin Enable For LLWU_P7
Enables and configures the edge detection for the wakeup pin.
00
01

External input pin disabled as wakeup input
External input pin enabled with rising edge detection
Table continues on the next page...

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Chapter 15 Low-Leakage Wakeup Unit (LLWU)

LLWU_PE2 field descriptions (continued)
Field

Description
10
11

5–4
WUPE6

Wakeup Pin Enable For LLWU_P6
Enables and configures the edge detection for the wakeup pin.
00
01
10
11

3–2
WUPE5

External input pin disabled as wakeup input
External input pin enabled with rising edge detection
External input pin enabled with falling edge detection
External input pin enabled with any change detection

Wakeup Pin Enable For LLWU_P5
Enables and configures the edge detection for the wakeup pin.
00
01
10
11

1–0
WUPE4

External input pin enabled with falling edge detection
External input pin enabled with any change detection

External input pin disabled as wakeup input
External input pin enabled with rising edge detection
External input pin enabled with falling edge detection
External input pin enabled with any change detection

Wakeup Pin Enable For LLWU_P4
Enables and configures the edge detection for the wakeup pin.
00
01
10
11

External input pin disabled as wakeup input
External input pin enabled with rising edge detection
External input pin enabled with falling edge detection
External input pin enabled with any change detection

15.3.3 LLWU Pin Enable 3 register (LLWU_PE3)
LLWU_PE3 contains the field to enable and select the edge detect type for the external
wakeup input pins LLWU_P11-LLWU_P8.
NOTE
This register is reset on Chip Reset not VLLS and by reset
types that trigger Chip Reset not VLLS. It is unaffected by reset
types that do not trigger Chip Reset not VLLS. See the
Introduction details for more information.
Address: 4007_C000h base + 2h offset = 4007_C002h
Bit

Read
Write
Reset

7

6

5

WUPE11
0

4

3

WUPE10
0

0

2

1

WUPE9
0

0

0

WUPE8
0

0

0

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LLWU_PE3 field descriptions
Field
7–6
WUPE11

Description
Wakeup Pin Enable For LLWU_P11
Enables and configures the edge detection for the wakeup pin.
00
01
10
11

5–4
WUPE10

Wakeup Pin Enable For LLWU_P10
Enables and configures the edge detection for the wakeup pin.
00
01
10
11

3–2
WUPE9

External input pin disabled as wakeup input
External input pin enabled with rising edge detection
External input pin enabled with falling edge detection
External input pin enabled with any change detection

Wakeup Pin Enable For LLWU_P9
Enables and configures the edge detection for the wakeup pin.
00
01
10
11

1–0
WUPE8

External input pin disabled as wakeup input
External input pin enabled with rising edge detection
External input pin enabled with falling edge detection
External input pin enabled with any change detection

External input pin disabled as wakeup input
External input pin enabled with rising edge detection
External input pin enabled with falling edge detection
External input pin enabled with any change detection

Wakeup Pin Enable For LLWU_P8
Enables and configures the edge detection for the wakeup pin.
00
01
10
11

External input pin disabled as wakeup input
External input pin enabled with rising edge detection
External input pin enabled with falling edge detection
External input pin enabled with any change detection

15.3.4 LLWU Pin Enable 4 register (LLWU_PE4)
LLWU_PE4 contains the field to enable and select the edge detect type for the external
wakeup input pins LLWU_P15-LLWU_P12.
NOTE
This register is reset on Chip Reset not VLLS and by reset
types that trigger Chip Reset not VLLS. It is unaffected by reset
types that do not trigger Chip Reset not VLLS. See the
Introduction details for more information.

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Chapter 15 Low-Leakage Wakeup Unit (LLWU)
Address: 4007_C000h base + 3h offset = 4007_C003h
Bit

Read
Write
Reset

7

6

5

WUPE15
0

4

3

WUPE14
0

0

2

1

WUPE13
0

0

0

WUPE12
0

0

0

LLWU_PE4 field descriptions
Field
7–6
WUPE15

Description
Wakeup Pin Enable For LLWU_P15
Enables and configures the edge detection for the wakeup pin.
00
01
10
11

5–4
WUPE14

Wakeup Pin Enable For LLWU_P14
Enables and configures the edge detection for the wakeup pin.
00
01
10
11

3–2
WUPE13

External input pin disabled as wakeup input
External input pin enabled with rising edge detection
External input pin enabled with falling edge detection
External input pin enabled with any change detection

Wakeup Pin Enable For LLWU_P13
Enables and configures the edge detection for the wakeup pin.
00
01
10
11

1–0
WUPE12

External input pin disabled as wakeup input
External input pin enabled with rising edge detection
External input pin enabled with falling edge detection
External input pin enabled with any change detection

External input pin disabled as wakeup input
External input pin enabled with rising edge detection
External input pin enabled with falling edge detection
External input pin enabled with any change detection

Wakeup Pin Enable For LLWU_P12
Enables and configures the edge detection for the wakeup pin.
00
01
10
11

External input pin disabled as wakeup input
External input pin enabled with rising edge detection
External input pin enabled with falling edge detection
External input pin enabled with any change detection

15.3.5 LLWU Module Enable register (LLWU_ME)
LLWU_ME contains the bits to enable the internal module flag as a wakeup input source
for inputs MWUF7-MWUF0.
NOTE
This register is reset on Chip Reset not VLLS and by reset
types that trigger Chip Reset not VLLS. It is unaffected by reset
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Memory map/register definition

types that do not trigger Chip Reset not VLLS. See the
Introduction details for more information.
Address: 4007_C000h base + 4h offset = 4007_C004h
Bit

Read
Write
Reset

7

6

5

4

3

2

1

0

WUME7

WUME6

WUME5

WUME4

WUME3

WUME2

WUME1

WUME0

0

0

0

0

0

0

0

0

LLWU_ME field descriptions
Field
7
WUME7

Description
Wakeup Module Enable For Module 7
Enables an internal module as a wakeup source input.
0
1

6
WUME6

Wakeup Module Enable For Module 6
Enables an internal module as a wakeup source input.
0
1

5
WUME5

Enables an internal module as a wakeup source input.

Enables an internal module as a wakeup source input.

Enables an internal module as a wakeup source input.
Internal module flag not used as wakeup source
Internal module flag used as wakeup source

Wakeup Module Enable For Module 2
Enables an internal module as a wakeup source input.
0
1

1
WUME1

Internal module flag not used as wakeup source
Internal module flag used as wakeup source

Wakeup Module Enable For Module 3

0
1
2
WUME2

Internal module flag not used as wakeup source
Internal module flag used as wakeup source

Wakeup Module Enable For Module 4

0
1
3
WUME3

Internal module flag not used as wakeup source
Internal module flag used as wakeup source

Wakeup Module Enable For Module 5

0
1
4
WUME4

Internal module flag not used as wakeup source
Internal module flag used as wakeup source

Internal module flag not used as wakeup source
Internal module flag used as wakeup source

Wakeup Module Enable for Module 1
Enables an internal module as a wakeup source input.
0
1

Internal module flag not used as wakeup source
Internal module flag used as wakeup source
Table continues on the next page...

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Chapter 15 Low-Leakage Wakeup Unit (LLWU)

LLWU_ME field descriptions (continued)
Field
0
WUME0

Description
Wakeup Module Enable For Module 0
Enables an internal module as a wakeup source input.
0
1

Internal module flag not used as wakeup source
Internal module flag used as wakeup source

15.3.6 LLWU Flag 1 register (LLWU_F1)
LLWU_F1 contains the wakeup flags indicating which wakeup source caused the MCU
to exit LLS or VLLS mode. For LLS, this is the source causing the CPU interrupt flow.
For VLLS, this is the source causing the MCU reset flow.
The external wakeup flags are read-only and clearing a flag is accomplished by a write of
a 1 to the corresponding WUFx bit. The wakeup flag (WUFx), if set, will remain set if
the associated WUPEx bit is cleared.
NOTE
This register is reset on Chip Reset not VLLS and by reset
types that trigger Chip Reset not VLLS. It is unaffected by reset
types that do not trigger Chip Reset not VLLS. See the
Introduction details for more information.
Address: 4007_C000h base + 5h offset = 4007_C005h
Bit

7

6

5

4

3

2

1

0

Read

WUF7

WUF6

WUF5

WUF4

WUF3

WUF2

WUF1

WUF0

Write

w1c

w1c

w1c

w1c

w1c

w1c

w1c

w1c

Reset

0

0

0

0

0

0

0

0

LLWU_F1 field descriptions
Field
7
WUF7

Description
Wakeup Flag For LLWU_P7
Indicates that an enabled external wakeup pin was a source of exiting a low-leakage power mode. To
clear the flag write a one to WUF7.
0
1

6
WUF6

LLWU_P7 input was not a wakeup source
LLWU_P7 input was a wakeup source

Wakeup Flag For LLWU_P6
Indicates that an enabled external wakeup pin was a source of exiting a low-leakage power mode. To
clear the flag write a one to WUF6.
Table continues on the next page...

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LLWU_F1 field descriptions (continued)
Field

Description
0
1

5
WUF5

Wakeup Flag For LLWU_P5
Indicates that an enabled external wakeup pin was a source of exiting a low-leakage power mode. To
clear the flag write a one to WUF5.
0
1

4
WUF4

Indicates that an enabled external wakeup pin was a source of exiting a low-leakage power mode. To
clear the flag write a one to WUF4.

Indicates that an enabled external wakeup pin was a source of exiting a low-leakage power mode. To
clear the flag write a one to WUF3.

Indicates that an enabled external wakeup pin was a source of exiting a low-leakage power mode. To
clear the flag write a one to WUF2.
LLWU_P2 input was not a wakeup source
LLWU_P2 input was a wakeup source

Wakeup Flag For LLWU_P1
Indicates that an enabled external wakeup pin was a source of exiting a low-leakage power mode. To
clear the flag write a one to WUF1.
0
1

0
WUF0

LLWU_P3 input was not a wakeup source
LLWU_P3 input was a wakeup source

Wakeup Flag For LLWU_P2

0
1
1
WUF1

LLWU_P4 input was not a wakeup source
LLWU_P4 input was a wakeup source

Wakeup Flag For LLWU_P3

0
1
2
WUF2

LLWU_P5 input was not a wakeup source
LLWU_P5 input was a wakeup source

Wakeup Flag For LLWU_P4

0
1
3
WUF3

LLWU_P6 input was not a wakeup source
LLWU_P6 input was a wakeup source

LLWU_P1 input was not a wakeup source
LLWU_P1 input was a wakeup source

Wakeup Flag For LLWU_P0
Indicates that an enabled external wakeup pin was a source of exiting a low-leakage power mode. To
clear the flag write a one to WUF0.
0
1

LLWU_P0 input was not a wakeup source
LLWU_P0 input was a wakeup source

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Chapter 15 Low-Leakage Wakeup Unit (LLWU)

15.3.7 LLWU Flag 2 register (LLWU_F2)
LLWU_F2 contains the wakeup flags indicating which wakeup source caused the MCU
to exit LLS or VLLS mode. For LLS, this is the source causing the CPU interrupt flow.
For VLLS, this is the source causing the MCU reset flow.
The external wakeup flags are read-only and clearing a flag is accomplished by a write of
a 1 to the corresponding WUFx bit. The wakeup flag (WUFx), if set, will remain set if
the associated WUPEx bit is cleared.
NOTE
This register is reset on Chip Reset not VLLS and by reset
types that trigger Chip Reset not VLLS. It is unaffected by reset
types that do not trigger Chip Reset not VLLS. See the
Introduction details for more information.
Address: 4007_C000h base + 6h offset = 4007_C006h
Bit

7

6

5

4

3

2

1

0

Read

WUF15

WUF14

WUF13

WUF12

WUF11

WUF10

WUF9

WUF8

Write

w1c

w1c

w1c

w1c

w1c

w1c

w1c

w1c

Reset

0

0

0

0

0

0

0

0

LLWU_F2 field descriptions
Field
7
WUF15

Description
Wakeup Flag For LLWU_P15
Indicates that an enabled external wakeup pin was a source of exiting a low-leakage power mode. To
clear the flag write a one to WUF15.
0
1

6
WUF14

Wakeup Flag For LLWU_P14
Indicates that an enabled external wakeup pin was a source of exiting a low-leakage power mode. To
clear the flag write a one to WUF14.
0
1

5
WUF13

LLWU_P15 input was not a wakeup source
LLWU_P15 input was a wakeup source

LLWU_P14 input was not a wakeup source
LLWU_P14 input was a wakeup source

Wakeup Flag For LLWU_P13
Indicates that an enabled external wakeup pin was a source of exiting a low-leakage power mode. To
clear the flag write a one to WUF13.
0
1

LLWU_P13 input was not a wakeup source
LLWU_P13 input was a wakeup source
Table continues on the next page...

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LLWU_F2 field descriptions (continued)
Field
4
WUF12

Description
Wakeup Flag For LLWU_P12
Indicates that an enabled external wakeup pin was a source of exiting a low-leakage power mode. To
clear the flag write a one to WUF12.
0
1

3
WUF11

Wakeup Flag For LLWU_P11
Indicates that an enabled external wakeup pin was a source of exiting a low-leakage power mode. To
clear the flag write a one to WUF11.
0
1

2
WUF10

Indicates that an enabled external wakeup pin was a source of exiting a low-leakage power mode. To
clear the flag write a one to WUF10.
LLWU_P10 input was not a wakeup source
LLWU_P10 input was a wakeup source

Wakeup Flag For LLWU_P9
Indicates that an enabled external wakeup pin was a source of exiting a low-leakage power mode. To
clear the flag write a one to WUF9.
0
1

0
WUF8

LLWU_P11 input was not a wakeup source
LLWU_P11 input was a wakeup source

Wakeup Flag For LLWU_P10

0
1
1
WUF9

LLWU_P12 input was not a wakeup source
LLWU_P12 input was a wakeup source

LLWU_P9 input was not a wakeup source
LLWU_P9 input was a wakeup source

Wakeup Flag For LLWU_P8
Indicates that an enabled external wakeup pin was a source of exiting a low-leakage power mode. To
clear the flag write a one to WUF8.
0
1

LLWU_P8 input was not a wakeup source
LLWU_P8 input was a wakeup source

15.3.8 LLWU Flag 3 register (LLWU_F3)
LLWU_F3 contains the wakeup flags indicating which internal wakeup source caused the
MCU to exit LLS or VLLS mode. For LLS, this is the source causing the CPU interrupt
flow. For VLLS, this is the source causing the MCU reset flow.
For internal peripherals that are capable of running in a low-leakage power mode, such as
iRTC or CMP modules, the flag from the associated peripheral is accessible as the
MWUFx bit. The flag will need to be cleared in the peripheral instead of writing a 1 to
the MWUFx bit.

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Chapter 15 Low-Leakage Wakeup Unit (LLWU)

NOTE
This register is reset on Chip Reset not VLLS and by reset
types that trigger Chip Reset not VLLS. It is unaffected by reset
types that do not trigger Chip Reset not VLLS. See the
Introduction details for more information.
Address: 4007_C000h base + 7h offset = 4007_C007h
Bit

Read

7

6

5

4

3

2

1

0

MWUF7

MWUF6

MWUF5

MWUF4

MWUF3

MWUF2

MWUF1

MWUF0

0

0

0

0

0

0

0

0

Write
Reset

LLWU_F3 field descriptions
Field
7
MWUF7

Description
Wakeup flag For module 7
Indicates that an enabled internal peripheral was a source of exiting a low-leakage power mode. To clear
the flag, follow the internal peripheral flag clearing mechanism.
0
1

6
MWUF6

Wakeup flag For module 6
Indicates that an enabled internal peripheral was a source of exiting a low-leakage power mode. To clear
the flag, follow the internal peripheral flag clearing mechanism.
0
1

5
MWUF5

Indicates that an enabled internal peripheral was a source of exiting a low-leakage power mode. To clear
the flag, follow the internal peripheral flag clearing mechanism.

Indicates that an enabled internal peripheral was a source of exiting a low-leakage power mode. To clear
the flag, follow the internal peripheral flag clearing mechanism.
Module 4 input was not a wakeup source
Module 4 input was a wakeup source

Wakeup flag For module 3
Indicates that an enabled internal peripheral was a source of exiting a low-leakage power mode. To clear
the flag, follow the internal peripheral flag clearing mechanism.
0
1

2
MWUF2

Module 5 input was not a wakeup source
Module 5 input was a wakeup source

Wakeup flag For module 4

0
1
3
MWUF3

Module 6 input was not a wakeup source
Module 6 input was a wakeup source

Wakeup flag For module 5

0
1
4
MWUF4

Module 7 input was not a wakeup source
Module 7 input was a wakeup source

Module 3 input was not a wakeup source
Module 3 input was a wakeup source

Wakeup flag For module 2
Table continues on the next page...

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Memory map/register definition

LLWU_F3 field descriptions (continued)
Field

Description
Indicates that an enabled internal peripheral was a source of exiting a low-leakage power mode. To clear
the flag, follow the internal peripheral flag clearing mechanism.
0
1

1
MWUF1

Wakeup flag For module 1
Indicates that an enabled internal peripheral was a source of exiting a low-leakage power mode. To clear
the flag, follow the internal peripheral flag clearing mechanism.
0
1

0
MWUF0

Module 2 input was not a wakeup source
Module 2 input was a wakeup source

Module 1 input was not a wakeup source
Module 1 input was a wakeup source

Wakeup flag For module 0
Indicates that an enabled internal peripheral was a source of exiting a low-leakage power mode. To clear
the flag, follow the internal peripheral flag clearing mechanism.
0
1

Module 0 input was not a wakeup source
Module 0 input was a wakeup source

15.3.9 LLWU Pin Filter 1 register (LLWU_FILT1)
LLWU_FILT1 is a control and status register that is used to enable/disable the digital
filter 1 features for an external pin.
NOTE
This register is reset on Chip Reset not VLLS and by reset
types that trigger Chip Reset not VLLS. It is unaffected by reset
types that do not trigger Chip Reset not VLLS. See the
Introduction details for more information.
Address: 4007_C000h base + 8h offset = 4007_C008h
Bit

7

Read

FILTF

Write

w1c

Reset

0

6

5

3

2

0

FILTE
0

4

0

0

1

0

0

0

FILTSEL
0

0

LLWU_FILT1 field descriptions
Field
7
FILTF

Description
Filter Detect Flag
Indicates that the filtered external wakeup pin, selected by FILTSEL, was a source of exiting a low-leakage
power mode. To clear the flag write a one to FILTF.
Table continues on the next page...

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Chapter 15 Low-Leakage Wakeup Unit (LLWU)

LLWU_FILT1 field descriptions (continued)
Field

Description
0
1

6–5
FILTE

Pin Filter 1 was not a wakeup source
Pin Filter 1 was a wakeup source

Digital Filter On External Pin
Controls the digital filter options for the external pin detect.
00
01
10
11

Filter disabled
Filter posedge detect enabled
Filter negedge detect enabled
Filter any edge detect enabled

4
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

3–0
FILTSEL

Filter Pin Select
Selects 1 out of the 16 wakeup pins to be muxed into the filter.
0000
...
1111

Select LLWU_P0 for filter
...
Select LLWU_P15 for filter

15.3.10 LLWU Pin Filter 2 register (LLWU_FILT2)
LLWU_FILT2 is a control and status register that is used to enable/disable the digital
filter 2 features for an external pin.
NOTE
This register is reset on Chip Reset not VLLS and by reset
types that trigger Chip Reset not VLLS. It is unaffected by reset
types that do not trigger Chip Reset not VLLS. See the
Introduction details for more information.
Address: 4007_C000h base + 9h offset = 4007_C009h
Bit

7

Read

FILTF

Write

w1c

Reset

0

6

5

FILTE
0

4

3

2

0

0

0

1

0

0

0

FILTSEL
0

0

LLWU_FILT2 field descriptions
Field
7
FILTF

Description
Filter Detect Flag
Indicates that the filtered external wakeup pin, selected by FILTSEL, was a source of exiting a low-leakage
power mode. To clear the flag write a one to FILTF.
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Functional description

LLWU_FILT2 field descriptions (continued)
Field

Description
0
1

6–5
FILTE

Pin Filter 2 was not a wakeup source
Pin Filter 2 was a wakeup source

Digital Filter On External Pin
Controls the digital filter options for the external pin detect.
00
01
10
11

Filter disabled
Filter posedge detect enabled
Filter negedge detect enabled
Filter any edge detect enabled

4
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

3–0
FILTSEL

Filter Pin Select
Selects 1 out of the 16 wakeup pins to be muxed into the filter.
0000
...
1111

Select LLWU_P0 for filter
...
Select LLWU_P15 for filter

15.4 Functional description
This on-chip peripheral module is called a low-leakage wakeup unit (LLWU) module
because it allows internal peripherals and external input pins as a source of wakeup from
low-leakage modes. It is operational only in LLS and VLLSx modes.
The LLWU module contains pin enables for each external pin and internal module. For
each external pin, the user can disable or select the edge type for the wakeup. Type
options are:
• Falling-edge
• Rising-edge
• Either-edge
When an external pin is enabled as a wakeup source, the pin must be configured as an
input pin.
The LLWU implements optional 3-cycle glitch filters, based on the LPO clock. A
detected external pin is required to remain asserted until the enabled glitch filter times
out. Additional latency of up to 2 cycles is due to synchronization, which results in a total
of up to 5 cycles of delay before the detect circuit alerts the system to the wakeup or reset
event when the filter function is enabled. Two wakeup detect filters are available to
detect up to two external pins. Glitch filtering is not provided on the internal modules.
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Chapter 15 Low-Leakage Wakeup Unit (LLWU)

For internal module wakeup operation, the WUMEx bit enables the associated module as
a wakeup source.

15.4.1 LLS mode
Wakeup events triggered from either an external pin input or an internal module input
result in a CPU interrupt flow to begin user code execution.

15.4.2 VLLS modes
In the case of a wakeup due to external pin or internal module wakeup, recovery is
always via a reset flow and the RCM_SRS[WAKEUP] is set indicating the low-leakage
mode was active. State retention data is lost and I/O will be restored after
PMC_REGSC[ACKISO] has been written.

15.4.3 Initialization
For an enabled peripheral wakeup input, the peripheral flag must be cleared by software
before entering LLS or VLLSx mode to avoid an immediate exit from the mode.
Flags associated with external input pins, filtered and unfiltered, must also be cleared by
software prior to entry to LLS or VLLSx mode.
After enabling an external pin filter or changing the source pin, wait at least 5 LPO clock
cycles before entering LLS or VLLSx mode to allow the filter to initialize.
NOTE
After recovering from a VLLS mode, user must restore chip
configuration before clearing ACKISO. In particular, pin
configuration for enabled LLWU wakeup pins must be restored
to avoid any LLWU flag from being falsely set when ACKISO
is cleared.
The signal selected as a wakeup source pin must be a digital
pin, as selected in the pin mux control.

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Chapter 16
Reset Control Module (RCM)
16.1 Introduction
This chapter describes the registers of the Reset Control Module (RCM). The RCM
implements many of the reset functions for the chip. See the chip's reset chapter for more
information.

16.2 Reset memory map and register descriptions
The Reset Control Module (RCM) registers provide reset status information and reset
filter control.
NOTE
The RCM registers can be written only in supervisor mode.
Write accesses in user mode are blocked and will result in a bus
error.
RCM memory map
Absolute
address
(hex)

Register name

Width
Access
(in bits)

Reset value

Section/
page

4007_F000

System Reset Status Register 0 (RCM_SRS0)

8

R

82h

16.2.1/265

4007_F001

System Reset Status Register 1 (RCM_SRS1)

8

R

00h

16.2.2/267

4007_F004

Reset Pin Filter Control register (RCM_RPFC)

8

R/W

00h

16.2.3/268

4007_F005

Reset Pin Filter Width register (RCM_RPFW)

8

R/W

00h

16.2.4/269

16.2.1 System Reset Status Register 0 (RCM_SRS0)
This register includes read-only status flags to indicate the source of the most recent
reset. The reset state of these bits depends on what caused the MCU to reset.
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Reset memory map and register descriptions

NOTE
The reset value of this register depends on the reset source:
• POR (including LVD) — 0x82
• LVD (without POR) — 0x02
• VLLS mode wakeup due to RESET pin assertion — 0x41
• VLLS mode wakeup due to other wakeup sources — 0x01
• Other reset — a bit is set if its corresponding reset source
caused the reset
Address: 4007_F000h base + 0h offset = 4007_F000h
Bit

Read

7

6

5

4

3

2

1

0

POR

PIN

WDOG

0

LOL

LOC

LVD

WAKEUP

1

0

0

0

0

0

1

0

Write
Reset

RCM_SRS0 field descriptions
Field
7
POR

Description
Power-On Reset
Indicates a reset has been caused by the power-on detection logic. Because the internal supply voltage
was ramping up at the time, the low-voltage reset (LVD) status bit is also set to indicate that the reset
occurred while the internal supply was below the LVD threshold.
0
1

6
PIN

External Reset Pin
Indicates a reset has been caused by an active-low level on the external RESET pin.
0
1

5
WDOG

3
LOL

Reset not caused by external reset pin
Reset caused by external reset pin

Watchdog
Indicates a reset has been caused by the watchdog timer Computer Operating Properly (COP) timing out.
This reset source can be blocked by disabling the COP watchdog: write 00 to the SIM's COPC[COPT]
field.
0
1

4
Reserved

Reset not caused by POR
Reset caused by POR

Reset not caused by watchdog timeout
Reset caused by watchdog timeout

This field is reserved.
This read-only field is reserved and always has the value 0.
Loss-of-Lock Reset
Indicates a reset has been caused by a loss of lock in the MCG PLL. See the MCG description for
information on the loss-of-clock event.
0
1

Reset not caused by a loss of lock in the PLL
Reset caused by a loss of lock in the PLL
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Chapter 16 Reset Control Module (RCM)

RCM_SRS0 field descriptions (continued)
Field
2
LOC

Description
Loss-of-Clock Reset
Indicates a reset has been caused by a loss of external clock. The MCG clock monitor must be enabled
for a loss of clock to be detected. Refer to the detailed MCG description for information on enabling the
clock monitor.
0
1

1
LVD

Low-Voltage Detect Reset
If the LVDRE bit is set and the supply drops below the LVD trip voltage, an LVD reset occurs. This bit is
also set by POR.
0
1

0
WAKEUP

Reset not caused by a loss of external clock.
Reset caused by a loss of external clock.

Reset not caused by LVD trip or POR
Reset caused by LVD trip or POR

Low Leakage Wakeup Reset
Indicates a reset has been caused by an enabled LLWU module wakeup source while the chip was in a
low leakage mode. In LLS mode, the RESET pin is the only wakeup source that can cause this reset. Any
enabled wakeup source in a VLLSx mode causes a reset. This bit is cleared by any reset except
WAKEUP.
0
1

Reset not caused by LLWU module wakeup source
Reset caused by LLWU module wakeup source

16.2.2 System Reset Status Register 1 (RCM_SRS1)
This register includes read-only status flags to indicate the source of the most recent
reset. The reset state of these bits depends on what caused the MCU to reset.
NOTE
The reset value of this register depends on the reset source:
• POR (including LVD) — 0x00
• LVD (without POR) — 0x00
• VLLS mode wakeup — 0x00
• Other reset — a bit is set if its corresponding reset source
caused the reset
Address: 4007_F000h base + 1h offset = 4007_F001h
Bit

7

6

5

4

3

2

1

0

Read

0

0

SACKERR

0

MDM_AP

SW

LOCKUP

0

0

0

0

0

0

0

0

0

Write
Reset

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RCM_SRS1 field descriptions
Field

Description

7
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

6
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

5
SACKERR

Stop Mode Acknowledge Error Reset
Indicates that after an attempt to enter Stop mode, a reset has been caused by a failure of one or more
peripherals to acknowledge within approximately one second to enter stop mode.
0
1

Reset not caused by peripheral failure to acknowledge attempt to enter stop mode
Reset caused by peripheral failure to acknowledge attempt to enter stop mode

4
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

3
MDM_AP

MDM-AP System Reset Request
Indicates a reset has been caused by the host debugger system setting of the System Reset Request bit
in the MDM-AP Control Register.
0
1

2
SW

Software
Indicates a reset has been caused by software setting of SYSRESETREQ bit in Application Interrupt and
Reset Control Register in the ARM core.
0
1

1
LOCKUP

Reset not caused by software setting of SYSRESETREQ bit
Reset caused by software setting of SYSRESETREQ bit

Core Lockup
Indicates a reset has been caused by the ARM core indication of a LOCKUP event.
0
1

0
Reserved

Reset not caused by host debugger system setting of the System Reset Request bit
Reset caused by host debugger system setting of the System Reset Request bit

Reset not caused by core LOCKUP event
Reset caused by core LOCKUP event

This field is reserved.
This read-only field is reserved and always has the value 0.

16.2.3 Reset Pin Filter Control register (RCM_RPFC)
NOTE
The reset values of bits 2-0 are for Chip POR only. They are
unaffected by other reset types.
NOTE
The bus clock filter is reset when disabled or when entering
stop mode. The LPO filter is reset when disabled .

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Chapter 16 Reset Control Module (RCM)
Address: 4007_F000h base + 4h offset = 4007_F004h
Bit

Read
Write
Reset

7

6

5

4

3

0
0

0

0

2

RSTFLTSS
0

0

0

1

0

RSTFLTSRW
0

0

RCM_RPFC field descriptions
Field
7–3
Reserved
2
RSTFLTSS

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
Reset Pin Filter Select in Stop Mode
Selects how the reset pin filter is enabled in Stop and VLPS modes , and also during LLS and VLLS
modes. On exit from VLLS mode, this bit should be reconfigured before clearing ACKISO in the PMC.
0
1

1–0
RSTFLTSRW

All filtering disabled
LPO clock filter enabled

Reset Pin Filter Select in Run and Wait Modes
Selects how the reset pin filter is enabled in run and wait modes.
00
01
10
11

All filtering disabled
Bus clock filter enabled for normal operation
LPO clock filter enabled for normal operation
Reserved

16.2.4 Reset Pin Filter Width register (RCM_RPFW)
NOTE
The reset values of the bits in the RSTFLTSEL field are for
Chip POR only. They are unaffected by other reset types.
Address: 4007_F000h base + 5h offset = 4007_F005h
Bit

Read
Write
Reset

7

6

5

4

3

0
0

0

2

1

0

0

0

RSTFLTSEL
0

0

0

0

RCM_RPFW field descriptions
Field
7–5
Reserved
4–0
RSTFLTSEL

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
Reset Pin Filter Bus Clock Select
Selects the reset pin bus clock filter width.
Table continues on the next page...

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Reset memory map and register descriptions

RCM_RPFW field descriptions (continued)
Field

Description
00000
00001
00010
00011
00100
00101
00110
00111
01000
01001
01010
01011
01100
01101
01110
01111
10000
10001
10010
10011
10100
10101
10110
10111
11000
11001
11010
11011
11100
11101
11110
11111

Bus clock filter count is 1
Bus clock filter count is 2
Bus clock filter count is 3
Bus clock filter count is 4
Bus clock filter count is 5
Bus clock filter count is 6
Bus clock filter count is 7
Bus clock filter count is 8
Bus clock filter count is 9
Bus clock filter count is 10
Bus clock filter count is 11
Bus clock filter count is 12
Bus clock filter count is 13
Bus clock filter count is 14
Bus clock filter count is 15
Bus clock filter count is 16
Bus clock filter count is 17
Bus clock filter count is 18
Bus clock filter count is 19
Bus clock filter count is 20
Bus clock filter count is 21
Bus clock filter count is 22
Bus clock filter count is 23
Bus clock filter count is 24
Bus clock filter count is 25
Bus clock filter count is 26
Bus clock filter count is 27
Bus clock filter count is 28
Bus clock filter count is 29
Bus clock filter count is 30
Bus clock filter count is 31
Bus clock filter count is 32

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Chapter 17
Bit Manipulation Engine (BME)
17.1 Introduction
The Bit Manipulation Engine (BME) provides hardware support for atomic read-modifywrite memory operations to the peripheral address space in Cortex-M0+ based
microcontrollers. This architectural capability is also known as "decorated storage" as it
defines a mechanism for providing additional semantics for load and store operations to
memory-mapped peripherals beyond just the reading and writing of data values to the
addressed memory locations. In the BME definition, the "decoration", that is, the
additional semantic information, is encoded into the peripheral address used to reference
the memory.
By combining the basic load and store instructions of the Cortex-M instruction set
architecture (v6M, v7M) with the concept of decorated storage provided by the BME, the
resulting implementation provides a robust and efficient read-modify-write capability to
this class of ultra low-end microcontrollers. The resulting architectural capability defined
by this core platform function is targeted at the manipulation of n-bit fields in peripheral
registers and is consistent with I/O hardware addressing in the Embedded C standard. For
most BME commands, a single core read or write bus cycle is converted into an atomic
read-modify-write, that is, an indivisible "read followed by a write" bus sequence.
BME decorated references are only available on system bus transactions generated by the
processor core and targeted at the standard 512 KB peripheral address space based at
0x4000_00001. The decoration semantic is embedded into address bits[28:19], creating a
448 MB space at addresses 0x4400_0000 - 0x5FFF_FFFF; these bits are stripped out of
the actual address sent to the peripheral bus controller and used by the BME to define and
control its operation.

1.

To be perfectly accurate, the peripheral address space occupies a 516 KB region: 512 KB based at 0x4000_0000 plus a 4
KB space based at 0x400F_F000 for GPIO accesses. This organization provides compatibility with the Kinetis K Family.
Attempted accesses to the memory space located between 0x4008_0000 - 0x400E_FFFF are error terminated due to an
illegal address.

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Introduction

17.1.1 Overview
The following figure is a generic block diagram of the processor core and platform for
this class of ultra low-end microcontrollers.
Cortex-M0+ Core

NVIC

CM0+ Core Platform

Fetch

Dbg
AGU

Dec

Rn

LD/ST

SHFT
ALU

MUL

AHB Bus

IO Port

MTB Port

32

PRAM

RAM
Array

RGPIO
m0

s1

AXBS
-Lite

Alt-Master
DMA_4ch

32

m3

s2

m2

s0

BME

PBRIDGE

32

FMC

Slave
Peripherals

NVM
Array

Note: BME can be accessed only by the core.

Figure 17-1. Generic Cortex-M0+ core platform block diagram

As shown in the block diagram, the BME module interfaces to a crossbar switch AHB
slave port as its primary input and sources an AHB bus output to the Peripheral Bridge
(PBRIDGE) controller. The BME hardware microarchitecture is a 2-stage pipeline design
matching the protocol of the AMBA-AHB system bus interfaces. The PBRIDGE module
converts the AHB system bus protocol into the IPS/APB protocol used by the attached
slave peripherals.

17.1.2 Features
The key features of the BME include:
• Lightweight implementation of decorated storage for peripheral address space
• Additional access semantics encoded into the reference address
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Chapter 17 Bit Manipulation Engine (BME)

•
•
•
•
•
•
•
•

Resides between a crossbar switch slave port and a peripheral bridge bus controller
2-stage pipeline design matching the AHB system bus protocol
Combinationally passes non-decorated accesses to peripheral bridge bus controller
Conversion of decorated loads and stores from processor core into atomic readmodify-writes
Decorated loads support unsigned bit field extracts, load-and-{set,clear}-1bit
operations
Decorated stores support bit field inserts, logical AND, OR and XOR operations
Support for byte, halfword and word-sized decorated operations
Supports minimum signal toggling on AHB output bus to reduce power dissipation

17.1.3 Modes of Operation
The BME module does not support any special modes of operation. As a memorymapped device located on a crossbar slave AHB system bus port, BME responds based
strictly on memory addresses for accesses to the connected peripheral bridge bus
controller.
All functionality associated with the BME module resides in the core platform's clock
domain; this includes its connections with the crossbar slave port and the PBRIDGE bus
controller.

17.2 External Signal Description
The BME module does not directly support any external interfaces.
The internal interfaces include two standard AHB buses with 32-bit datapath widths: the
primary input from the appropriate crossbar slave port (mx_h) and the primary
output to the PBRIDGE bus controller (sx_h).
Note the signal directions are defined by the BME's view and are labeled based on the
dominant direction. Accordingly, the mx_h AHB bus is the primary input, even
though there are certain data phase signals (mx_h{rdata, ready, resp}) which are outputs
from BME. Likewise, the sx_h AHB bus is the primary output even though there
are specific data phase signals (sx_h{rdata, ready, resp}) which are inputs to BME.

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Memory Map and Register Definition

17.3 Memory Map and Register Definition
The BME module provides a memory-mapped capability and does not include any
programming model registers. The exact set of functions supported by the BME are
detailed in the Functional Description.
The peripheral address space occupies a 516 KB region: 512 KB based at 0x4000_0000
plus a 4 KB space based at 0x400F_F000 for GPIO accesses; the decorated address space
is mapped to the 448 MB region located at 0x4400_0000 - 0x5FFF_FFFF.

17.4 Functional Description
This section details the specific functions supported by the BME.
Recall the combination of the basic load and store instructions of the Cortex-M
instruction set architecture (v6M, v7M) plus the concept of decorated storage provided by
the BME, the resulting implementation provides a robust and efficient read-modify-write
capability to this class of ultra low-end microcontrollers. The resulting architectural
capability defined by this core platform function is targeted at the manipulation of n-bit
fields in peripheral registers and is consistent with I/O hardware addressing in the
Embedded C standard. For most BME commands, a single core read or write bus cycle is
converted into an atomic read-modify-write, that is, an indivisible "read followed by a
write" bus sequence.
Consider decorated store operations first, then decorated loads.

17.4.1 BME Decorated Stores
The functions supported by the BME's decorated stores include three logical operators
(AND, OR, XOR) plus a bit field insert. For all these operations, BME converts a single
decorated AHB store transaction into a 2-cycle atomic read-modify-write sequence,
where the combined read-modify operation is performed in the first AHB data phase, and
then the write is performed in the second AHB data phase.
A generic timing diagram of a decorated store showing a bit field insert operation is
shown as follows:

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Chapter 17 Bit Manipulation Engine (BME)

CYCLE RULER

x

x+1

x+2

x+3

hclk
BME AHB Input Bus
mx_haddr

next

5..v_wxyz

mx_hattr

next

mx_hwrite

next

mx_hwdata

wdata

mx_hrdata
mx_hready
BME AHB Output Bus
sx_haddr

400v_wxyz

400v_wxyz

next

sx_hattr

next

sx_hwrite

next

sx_hwdata

wdata bfi rdata

sx_hrdata

rdata

sx_hready
BME States + Datapath
control_state_dp1
control_state_dp2
reg_addr_data_dp

5..v_wxyz

wdata bfi rdata

Figure 17-2. Decorated store: bit field insert timing diagram

All the decorated store operations follow the same execution template shown in the figure
above, a 2-cycle read-modify-write operation:
• Cycle x, 1st AHB address phase: Write from input bus (mx_h) is translated
into a read operation on the output bus (sx_h) using the actual memory
address (with the decoration removed) and then captured in a register
(reg_addr_data_dp)
• Cycle x+1, 2nd AHB address phase: Write access with the registered (but actual)
memory address is output (sx_h)
• Cycle x+1, 1st AHB data phase: Memory read data (sx_hrdata) is modified using the
input bus write data (mx_hwdata) and the function defined by the decoration and
captured in a data register (reg_addr_data_dp); the input bus cycle is stalled
(mx_hready = 0)
• Cycle x+2, 2nd AHB data phase: Registered write data is sourced onto the output
write data bus (sx_hwdata)

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Functional Description

NOTE
Any wait states inserted by the peripheral slave device
(sx_hready = 0) are simply passed through the BME back to the
master input bus, stalling the AHB transaction cycle for cycle.

17.4.1.1 Decorated Store Logical AND (AND)
This command performs an atomic read-modify-write of the referenced memory location.
First, the location is read; it is then modified by performing a logical AND operation
using the write data operand sourced for the system bus cycle; finally, the result of the
AND operation is written back into the referenced memory location.
The data size is specified by the write operation and can be byte (8-bit), halfword (16-bit)
or word (32-bit). The core performs the required write data lane replication on byte and
halfword transfers.
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10

9

8

ioandb 0

1

0

0

0

1

-

-

-

-

-

-

mem_addr

ioandh 0

1

0

0

0

1

-

-

-

-

-

-

mem_addr

ioandw 0

1

0

0

0

1

-

-

-

-

-

-

mem_addr

7

6

5

4

3

2

1

0

0
0

0

Figure 17-3. Decorated store address: logical AND

where addr[28:26] = 001 specifies the AND operation, and mem_addr[19:0] specifies the
address offset into the peripheral space based at 0x4000_0000. The "-" indicates an
address bit "don't care".
The decorated AND write operation is defined in the following pseudo-code as:
ioand(accessAddress, wdata)
tmp
= mem[accessAddress & 0xE00FFFFF, size]
tmp
= tmp & wdata
mem[accessAddress & 0xE00FFFFF, size] = tmp

//
//
//
//

decorated store AND
memory read
modify
memory write

where the operand size  is defined as b(yte, 8-bit), h(alfword, 16-bit) and w(ord, 32bit). This notation is used throughout the document.
In the cycle definition tables, the notation AHB_ap and AHB_dp refers to the address and
data phases of the BME AHB transaction. The cycle-by-cycle BME operations are
detailed in the following table.

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Chapter 17 Bit Manipulation Engine (BME)

Table 17-1. Cycle definitions of decorated store: logical AND
Pipeline Stage

Cycle
x

BME AHB_ap

x+1

Forward addr to memory;
Decode decoration; Convert
master_wt to slave_rd;
Capture address, attributes

BME AHB_dp



x+2

Recirculate captured addr +
attr to memory as slave_wt



Perform memory read; Form
(rdata & wdata) and capture
destination data in register

Perform write sending
registered data to memory

17.4.1.2 Decorated Store Logical OR (OR)
This command performs an atomic read-modify-write of the referenced memory location.
First, the location is read; it is then modified by performing a logical OR operation using
the write data operand sourced for the system bus cycle; finally, the result of the OR
operation is written back into the referenced memory location.
The data size is specified by the write operation and can be byte (8 bit), halfword (16 bit)
or word (32 bit). The core performs the required write data lane replication on byte and
halfword transfers.
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10

9

8

ioorb 0

1

0

0

1

0

-

-

-

-

-

-

mem_addr

ioorh 0

1

0

0

1

0

-

-

-

-

-

-

mem_addr

ioorw 0

1

0

0

1

0

-

-

-

-

-

-

mem_addr

7

6

5

4

3

2

1

0

0
0

0

Figure 17-4. Decorated Address Store: Logical OR

where addr[28:26] = 010 specifies the OR operation, and mem_addr[19:0] specifies the
address offset into the peripheral space based at 0x4000_0000. The "-" indicates an
address bit "don't care".
The decorated OR write operation is defined in the following pseudo-code as:
ioor(accessAddress, wdata)

// decorated store OR

tmp
= mem[accessAddress & 0xE00FFFFF, size]
tmp
= tmp | wdata
mem[accessAddress & 0xE00FFFFF, size] = tmp

// memory read
// modify
// memory write

The cycle-by-cycle BME operations are detailed in the following table

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Functional Description

Table 17-2. Cycle definitions of decorated store: logical OR
Pipeline Stage

Cycle
x

BME AHB_ap

x+1

Forward addr to memory;
Decode decoration; Convert
master_wt to slave_rd;
Capture address, attributes

BME AHB_dp



x+2

Recirculate captured addr +
attr to memory as slave_wt



Perform memory read; Form
(rdata | wdata) and capture
destination data in register

Perform write sending
registered data to memory

17.4.1.3 Decorated Store: Logical XOR (XOR)
This command performs an atomic read-modify-write of the referenced memory location.
First, the location is read; it is then modified by performing a logical XOR (exclusiveOR) operation using the write data operand sourced for the system bus cycle; finally, the
result of the XOR operation is written back into the referenced memory location.
The data size is specified by the write operation and can be byte (8-bit), halfword (16-bit)
or word (32-bit). The core performs the required write data lane replication on byte and
halfword transfers.
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10

9

8

ioxorb 0

1

0

0

1

1

-

-

-

-

-

-

mem_addr

ioxorh 0

1

0

0

1

1

-

-

-

-

-

-

mem_addr

ioxorw 0

1

0

0

1

1

-

-

-

-

-

-

mem_addr

7

6

5

4

3

2

1

0

0
0

0

Figure 17-5. Decorated Address Store: Logical XOR

where addr[28:26] = 011 specifies the XOR operation, and mem_addr[19:0] specifies the
address offset into the peripheral space based at 0x4000_0000. The "-" indicates an
address bit "don't care".
The decorated XOR write operation is defined in the following pseudo-code as:
ioxor(accessAddress, wdata)

// decorated store XOR

tmp
= mem[accessAddress & 0xE00FFFFF, size]
tmp
= tmp ^ wdata
mem[accessAddress & 0xE00FFFFF, size] = tmp

// memory read
// modify
// memory write

The cycle-by-cycle BME operations are detailed in the following table.

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Table 17-3. Cycle definitions of decorated store: logical XOR
Pipeline Stage

Cycle
x

BME AHB_ap

Forward addr to memory;
Decode decoration; Convert
master_wt to slave_rd;
Capture address, attributes

BME AHB_dp



x+1

x+2

Recirculate captured addr +
attr to memory as slave_wt



Perform memory read; Form
(rdata ^ wdata) and capture
destination data in register

Perform write sending
registered data to memory

17.4.1.4 Decorated Store Bit Field Insert (BFI)
This command inserts a bit field contained in the write data operand, defined by LSB
position (b) and the bit field width (w+1), into the memory "container" defined by the
access size associated with the store instruction using an atomic read-modify-write
sequence.
The data size is specified by the write operation and can be byte (8-bit), halfword (16-bit)
or word (32-bit). Note for the word sized operation, the maximum bit field width is 16
bits. The core performs the required write data lane replication on byte and halfword
transfers.
The BFI operation can be used to insert a single bit into a peripheral. For this case, the w
field is simply set to 0, indicating a bit field width of 1.
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10

-

9

8

iobfib 0

1

0

1

-

-

b

b

b

w w w

mem_addr

iobfih 0

1

0

1

-

b

b

b

b w w w w

mem_addr

iobfiw 0

1

0

1

b

b

b

b

b w w w w

mem_addr

7

6

5

4

3

2

1

0

0
0

0

Figure 17-6. Decorated address store: bit field insert

where addr[28] = 1 signals a BFI operation, addr[27:23] is "b", the LSB identifier,
addr[22:19] is "w", the bit field width minus 1 identifier, and addr[18:0] specifies the
address offset into the peripheral space based at 0x4000_0000. The "-" indicates an
address bit "don't care". Note, unlike the other decorated store operations, BFI uses
addr[19] as the least significant bit in the "w" specifier and not as an address bit.
The decorated BFI write operation is defined in the following pseudo-code as:
iobfi(accessAddress, wdata)

// decorated bit field insert

tmp
mask

// memory read
// generate bit mask

= mem[accessAddress & 0xE007FFFF, size]
= ((1 << (w+1)) - 1) << b

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Functional Description
tmp

= tmp
& ~mask
| wdata & mask
mem[accessAddress & 0xE007FFFF, size] = tmp

// modify
// memory write

The write data operand (wdata) associated with the store instruction contains the bit field
to be inserted. It must be properly aligned within a right-justified container, that is, within
the lower 8 bits for a byte operation, the lower 16 bits for a halfword or the entire 32 bits
for a word operation.
To illustrate, consider the following example of the insertion of the 3-bit field "xyz" into
an 8-bit memory container, initially set to "abcd_efgh". For all cases, w is 2, signaling a
bit field width of 3.
if b = 0 and the decorated store (strb)
then destination is "abcd_exyz"
if b = 1 and the decorated store (strb)
then destination is "abcd_xyzh"
if b = 2 and the decorated store (strb)
then destination is "abcx_yzgh"
if b = 3 and the decorated store (strb)
then destination is "abxy_zfgh"
if b = 4 and the decorated store (strb)
then destination is "axyz_efgh"
if b = 5 and the decorated store (strb)
then destination is "xyzd_efgh"
if b = 6 and the decorated store (strb)
then destination is "yzcd_efgh"
if b = 7 and the decorated store (strb)
then destination is "zbcd_efgh"

Rt register[7:0] = ----_-xyz,
Rt register[7:0] = ----_xyz-,
Rt register[7:0] = ---x_yz--,
Rt register[7:0] = --xy_z---,
Rt register[7:0] = -xyz_----,
Rt register[7:0] = xyz-_----,
Rt register[7:0] = yz--_----,
Rt register[7:0] = z---_----,

Note from the example, when the starting bit position plus the field width exceeds the
container size, only part of the source bit field is inserted into the destination memory
location. Stated differently, if (b + w+1) > container_width, only the low-order
"container_width - b" bits are actually inserted.
The cycle-by-cycle BME operations are detailed in the following table.
Table 17-4. Cycle definitions of decorated store: bit field insert
Pipeline Stage

Cycle
x

BME AHB_ap

BME AHB_dp

Forward addr to memory;
Decode decoration; Convert
master_wt to slave_rd;
Capture address, attributes


x+1

x+2

Recirculate captured addr +
attr to memory as slave_wt

Perform memory read; Form
bit mask; Form bitwise
((mask) ? wdata : rdata)) and
capture destination data in
register



Perform write sending
registered data to memory

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17.4.2 BME Decorated Loads
The functions supported by the BME's decorated loads include two single-bit load-and{set, clear} operators plus unsigned bit field extracts. For the two load-and-{set, clear}
operations, BME converts a single decorated AHB load transaction into a 2-cycle atomic
read-modify-write sequence, where the combined read-modify operations are performed
in the first AHB data phase, and then the write is performed in the second AHB data
phase as the original read data is returned to the processor core. For an unsigned bit field
extract, the decorated load transaction is stalled for one cycle in the BME as the data field
is extracted, then aligned and returned to the processor in the 2nd AHB data phase. This
is the only decorated transaction that is not an atomic read-modify-write, as it is a simple
data read.
A generic timing diagram of a decorated load showing a load-and-set 1-bit operation is
shown as follows.
CYCLE RULER

x

x+1

x+2

x+3

hclk
BME AHB Input Bus
mx_haddr

4c.v_wxyz

next

mx_hattr

next

mx_hwrite

next

mx_hwdata
orig_1bit

mx_hrdata
mx_hready
BME AHB Output Bus
sx_haddr

400v_wxyz

400v_wxyz

next

sx_hattr

next

sx_hwrite

next

sx_hwdata

rdata + 1bit

sx_hrdata

rdata

sx_hready
BME States + Datapath
control_state_dp1
control_state_dp2
reg_addr_data_dp

4c.v_wxyz

rdata + 1bit

Figure 17-7. Decorated load: load-and-set 1-bit field insert timing diagram

Decorated load-and-{set, clear} 1-bit operations follow the execution template shown in
the above figure: a 2-cycle read-modify-write operation:
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Functional Description

• Cycle x, 1st AHB address phase: Read from input bus is translated into a read
operation on the output bus with the actual memory address (with the decoration
removed) and then captured in a register
• Cycle x+1, 2nd AHB address phase: Write access with the registered (but actual)
memory address is output
• Cycle x+1, 1st AHB data phase: The "original" 1-bit memory read data is captured in
a register, while the 1-bit field is set or clear based on the function defined by the
decoration with the modified data captured in a register; the input bus cycle is stalled
• Cycle x+2, 2nd AHB data phase: The selected original 1-bit is right justified, zero
filled and then driven onto the input read data bus, while the registered write data is
sourced onto the output write data bus
NOTE
Any wait states inserted by the peripheral slave device
(sx_hready = 0) are simply passed through the BME back to the
master input bus, stalling the AHB transaction cycle for cycle.
A generic timing diagram of a decorated load showing an unsigned bit field operation is
shown in the following figure.

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CYCLE RULER

1

2

3

4

hclk
BME AHB Input Bus
mx_haddr

5..v_wxyz

next

mx_hattr

next

mx_hwrite

next

mx_hwdata
ubfx

mx_hrdata
mx_hready
BME AHB Output Bus
sx_haddr

400v_wxyz

next

sx_hattr

next

sx_hwrite

next

sx_hwdata
sx_hrdata

rdata

sx_hready
BME States + Datapath
control_state_dp1
control_state_dp2
reg_addr_data_dp

5..v_wxyz

rdata

Figure 17-8. Decorated load: unsigned bit field insert timing diagram

The decorated unsigned bit field extract follows the same execution template shown in
the above figure, a 2-cycle read operation:
• Cycle x, 1st AHB address phase: Read from input bus is translated into a read
operation on the output bus with the actual memory address (with the decoration
removed) and then captured in a register
• Cycle x+1, 2nd AHB address phase: Idle cycle
• Cycle x+1, 1st AHB data phase: A bit mask is generated based on the starting bit
position and the field width; the mask is AND'ed with the memory read data to
isolate the bit field; the resulting data is captured in a data register; the input bus
cycle is stalled
• Cycle x+2, 2nd AHB data phase: Registered data is logically right shifted for proper
alignment and driven onto the input read data bus
NOTE
Any wait states inserted by the peripheral slave device
(sx_hready = 0) are simply passed through the BME back to the
master input bus, stalling the AHB transaction cycle for cycle.
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Functional Description

17.4.2.1 Decorated Load Load-and-Clear 1 Bit (LAC1)
This command loads a 1-bit field defined by the LSB position (b) into the core's general
purpose destination register (Rt) and zeroes the bit in the memory space after performing
an atomic read-modify-write sequence.
The extracted one bit data field from the memory address is right justified and zero filled
in the operand returned to the core.
The data size is specified by the read operation and can be byte (8-bit), halfword (16-bit)
or word (32-bit).
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10

iolac1b 0

1

0

0

1

0

iolac1h 0

1

0

0

1

iolac1w 0

1

0

0

1

9

8

-

-

b

b

b

-

mem_addr

0

-

b

b

b

b

-

mem_addr

0

b

b

b

b

b

-

mem_addr

7

6

5

4

3

2

1

0

0
0

0

Figure 17-9. Decorated load address: load-and-clear 1 bit

where addr[28:26] = 010 specifies the load-and-clear 1 bit operation, addr[25:21] is "b",
the bit identifier, and mem_addr[19:0] specifies the address offset into the peripheral
space based at 0x4000_0000. The "-" indicates an address bit "don't care".
The decorated Load-and-Clear 1 Bit read operation is defined in the following pseudocode as:
rdata =

iolac1(accessAddress)

// decorated load-and-clear 1

tmp
= mem[accessAddress & 0xE00FFFFF, size]
mask = 1 << b
rdata = (tmp & mask) >> b
tmp
= tmp & ~mask
mem[accessAddress & 0xE00FFFFF, size] = tmp

//
//
//
//
//

memory read
generate bit mask
read data returned to core
modify
memory write

The cycle-by-cycle BME operations are detailed in the following table.
Table 17-5. Cycle definitions of decorated load: load-and-clear 1 bit
Pipeline Stage

Cycle
x

BME AHB_ap

BME AHB_dp

Forward addr to memory;
Decode decoration; Capture
address, attributes


x+1

x+2

Recirculate captured addr +
attr to memory as slave_wt



Perform memory read; Form
bit mask; Extract bit from
rdata; Form (rdata & ~mask)
and capture destination data
in register

Return extracted bit to master;
Perform write sending
registered data to memory

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17.4.2.2 Decorated Load: Load-and-Set 1 Bit (LAS1)
This command loads a 1-bit field defined by the LSB position (b) into the core's general
purpose destination register (Rt) and sets the bit in the memory space after performing an
atomic read-modify-write sequence.
The extracted one bit data field from the memory address is right justified and zero filled
in the operand returned to the core.
The data size is specified by the read operation and can be byte (8-bit), halfword (16-bit)
or word (32-bit).
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10

9

8

iolas1b 0

1

0

0

1

1

-

-

b

b

b

-

mem_addr

iolas1h 0

1

0

0

1

1

-

b

b

b

b

-

mem_addr

iolas1w 0

1

0

0

1

1

b

b

b

b

b

-

mem_addr

7

6

5

4

3

2

1

0

0
0

0

Figure 17-10. Decorated load address: load-and-set 1 bit

where addr[28:26] = 011 specifies the load-and-set 1 bit operation, addr[25:21] is "b", the
bit identifier, and mem_addr[19:0] specifies the address offset into the peripheral space
based at 0x4000_0000. The "-" indicates an address bit "don't care".
The decorated Load-and-Set 1 Bit read operation is defined in the following pseudo-code
as:
rdata =

iolas1(accessAddress)

// decorated load-and-set 1

tmp
= mem[accessAddress & 0xE00FFFFF, size]
mask = 1 << b
rdata = (tmp & mask) >> b
tmp
= tmp | mask
mem[accessAddress & 0xE00FFFFF, size] = tmp

//
//
//
//
//

memory read
generate bit mask
read data returned to core
modify
memory write

The cycle-by-cycle BME operations are detailed in the following table.
Table 17-6. Cycle definitions of decorated load: load-and-set 1-bit
Pipeline Stage

Cycle
x

BME AHB_ap

Forward addr to memory;
Decode decoration; Capture
address, attributes

BME AHB_dp



x+1

x+2

Recirculate captured addr +
attr to memory as slave_wt



Perform memory read; Form
bit mask; Extract bit from
rdata; Form (rdata | mask)
and capture destination data
in register

Return extracted bit to master;
Perform write sending
registered data to memory

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Functional Description

17.4.2.3 Decorated Load Unsigned Bit Field Extract (UBFX)
This command extracts a bit field defined by LSB position (b) and the bit field width (w
+1) from the memory "container" defined by the access size associated with the load
instruction using a 2-cycle read sequence.
The extracted bit field from the memory address is right justified and zero filled in the
operand returned to the core. Recall this is the only decorated operation that does not
perform a memory write, that is, UBFX only performs a read.
The data size is specified by the write operation and can be byte (8-bit), halfword (16-bit)
or word (32-bit). Note for the word sized operation, the maximum bit field width is 16
bits.
The use of a UBFX operation is recommended to extract a single bit from a peripheral.
For this case, the w field is simply set to 0, indicating a bit field width of 1.
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10

-

9

8

7

ioubfxb 0

1

0

1

-

-

b

b

b

w w w

mem_addr

ioubfxh 0

1

0

1

-

b

b

b

b w w w w

mem_addr

ioubfxw 0

1

0

1

b

b

b

b

b w w w w

mem_addr

6

5

4

3

2

1

0

0
0

0

Figure 17-11. Decorated load address: unsigned bit field extract

where addr[28] = 1 specifies the unsigned bit field extract operation, addr[27:23] is "b",
the LSB identifier, addr[22:19] is "w", the bit field width minus 1 identifier, and
mem_addr[18:0] specifies the address offset into the peripheral space based at
0x4000_0000. The "-" indicates an address bit "don't care". Note, unlike the other
decorated load operations, UBFX uses addr[19] as the least significant bit in the "w"
specifier and not as an address bit.
The decorated unsigned bit field extract read operation is defined in the following
pseudo-code as:
rdata =

ioubfx(accessAddress)

tmp
= mem[accessAddress & 0xE007FFFF, size]
mask = ((1 << (w+1)) - 1) << b
rdata = (tmp & mask) >> b

// unsigned bit field extract
// memory read
// generate bit mask
// read data returned to core

Like the BFI operation, when the starting bit position plus the field width exceeds the
container size, only part of the source bit field is extracted from the destination memory
location. Stated differently, if (b + w+1) > container_width, only the low-order
"container_width - b" bits are actually extracted. The cycle-by-cycle BME operations are
detailed in the following table.
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Chapter 17 Bit Manipulation Engine (BME)

Table 17-7. Cycle definitions of decorated load: unsigned bit field extract
Pipeline Stage

Cycle
x

BME AHB_ap

Forward addr to memory;
Decode decoration; Capture
address, attributes

BME AHB_dp



x+1
Idle AHB address phase

x+2


Perform memory read; Form Logically right shift registered
bit mask; Form (rdata & mask) data; Return justified rdata to
and capture destination data master
in register

17.4.3 Additional Details on Decorated Addresses and GPIO
Accesses
As previously noted, the peripheral address space occupies a 516 KB region: 512 KB
based at 0x4000_0000 plus a 4 KB space based at 0x400F_F000 for GPIO accesses. This
memory layout provides compatibility with the Kinetis K Family and provides 129
address "slots", each 4 KB in size.
The GPIO address space is multiply-mapped by the hardware: it appears at the "standard"
system address 0x400F_F000 and is physically located in the address slot corresponding
to address 0x4000_F000. Decorated loads and stores create a slight complication
involving accesses to the GPIO. Recall the use of address[19] varies by decorated
operation; for AND, OR, XOR, LAC1 and LAS1, this bit functions as a true address bit,
while for BFI and UBFX, this bit defines the least significant bit of the "w" bit field
specifier.
As a result, undecorated GPIO references and decorated AND, OR, XOR, LAC1 and
LAS1 operations can use the standard 0x400F_F000 base address, while decorated BFI
and UBFX operations must use the alternate 0x4000_F000 base address. Another
implementation can simply use 0x400F_F000 as the base address for all undecorated
GPIO accesses and 0x4000_F000 as the base address for all decorated accesses. Both
implementations are supported by the hardware.
Table 17-8. Decorated peripheral and GPIO address details
Peripheral address space

Description

0x4000_0000 - 0x4007_FFFF

Undecorated (normal) peripheral accesses

0x4008_0000 - 0x400F_EFFF

Illegal addresses; attempted references are aborted and error terminated

0x400F_F000 - 0x400F_FFFF

Undecorated (normal) GPIO accesses using standard address

0x4010_0000 - 0x43FF_FFFF

Illegal addresses; attempted references are aborted and error terminated
Table continues on the next page...

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Application Information

Table 17-8. Decorated peripheral and GPIO address details (continued)
Peripheral address space

Description

0x4400_0000 - 0x4FFF_FFFF

Decorated AND, OR, XOR, LAC1, LAS1 references to peripherals and GPIO based at
either 0x4000_F000 or 0x400F_F000

0x5000_0000 - 0x5FFF_FFFF

Decorated BFI, UBFX references to peripherals and GPIO only based at 0x4000_F000

17.5 Application Information
In this section, GNU assembler macros with C expression operands are presented as
examples of the required instructions to perform decorated operations. This section
specifically presents a partial bme.h file defining the assembly language expressions for
decorated logical stores: AND, OR and XOR. Comparable functions for BFI and the
decorated loads are more complex and available in the complete BME header file.
These macros use the same function names presented in Functional Description.
#define IOANDW(ADDR,WDATA)
\
__asm("ldr
r3, =(1<<26);"
\
"orr
r3, %[addr];"
\
"mov
r2, %[wdata];"
\
"str
r2, [r3];"
\
:: [addr] "r" (ADDR), [wdata] "r" (WDATA) : "r2", "r3");
#define IOANDH(ADDR,WDATA)
\
__asm("ldr
r3, =(1<<26);"
\
"orr
r3, %[addr];"
\
"mov
r2, %[wdata];"
\
"strh
r2, [r3];"
\
:: [addr] "r" (ADDR), [wdata] "r" (WDATA) : "r2", "r3");
#define IOANDB(ADDR,WDATA)
\
__asm("ldr
r3, =(1<<26);"
\
"orr
r3, %[addr];"
\
"mov
r2, %[wdata];"
\
"strb
r2, [r3];"
\
:: [addr] "r" (ADDR), [wdata] "r" (WDATA) : "r2", "r3");
#define IOORW(ADDR,WDATA)
\
__asm("ldr
r3, =(1<<27);"
\
"orr
r3, %[addr];"
\
"mov
r2, %[wdata];"
\
"str
r2, [r3];"
\
:: [addr] "r" (ADDR), [wdata] "r" (WDATA) : "r2", "r3");
#define IOORH(ADDR,WDATA)
\
__asm("ldr
r3, =(1<<27);"
\
"orr
r3, %[addr];"
\
"mov
r2, %[wdata];"
\
"strh
r2, [r3];"
\
:: [addr] "r" (ADDR), [wdata] "r" (WDATA) : "r2", "r3");
#define IOORB(ADDR,WDATA)
__asm("ldr
r3, =(1<<27);"
"orr
r3, %[addr];"
"mov
r2, %[wdata];"
"strb
r2, [r3];"

\
\
\
\
\

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Chapter 17 Bit Manipulation Engine (BME)
:: [addr] "r" (ADDR), [wdata] "r" (WDATA) : "r2", "r3");
#define IOXORW(ADDR,WDATA)
\
__asm("ldr
r3, =(3<<26);"
\
"orr
r3, %[addr];"
\
"mov
r2, %[wdata];"
\
"str
r2, [r3];"
\
:: [addr] "r" (ADDR), [wdata] "r" (WDATA) : "r2", "r3");
#define IOXORH(ADDR,WDATA)
\
__asm("ldr
r3, =(3<<26);"
\
"orr
r3, %[addr];"
\
"mov
r2, %[wdata];"
\
"strh
r2, [r3];"
\
:: [addr] "r" (ADDR), [wdata] "r" (WDATA) : "r2", "r3");
#define IOXORB(ADDR,WDATA)
\
__asm("ldr
r3, =(3<<26);"
\
"orr
r3, %[addr];"
\
"mov
r2, %[wdata];"
\
"strb
r2, [r3];"
\
:: [addr] "r" (ADDR), [wdata] "r" (WDATA) : "r2", "r3");

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Chapter 18
Miscellaneous Control Module (MCM)
18.1 Introduction
NOTE
For the chip-specific implementation details of this module's
instances see the chip configuration information.
The Miscellaneous Control Module (MCM) provides a myriad of miscellaneous control
functions.

18.1.1 Features
The MCM includes the following features:
• Program-visible information on the platform configuration
• Crossbar master arbitration policy selection
• Flash controller speculation buffer and cache configurations

18.2 Memory map/register descriptions
The memory map and register descriptions below describe the registers using byte
addresses.
MCM memory map
Absolute
address
(hex)
F000_3008

Register name
Crossbar Switch (AXBS) Slave Configuration
(MCM_PLASC)

Width
Access
(in bits)
16

Reset value

Section/
page

0007h

18.2.1/292

R

Table continues on the next page...

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Memory map/register descriptions

MCM memory map (continued)
Absolute
address
(hex)
F000_300A

Width
Access
(in bits)

Register name
Crossbar Switch (AXBS) Master Configuration
(MCM_PLAMC)

Reset value

Section/
page

16

R

000Dh

18.2.2/293

F000_300C Platform Control Register (MCM_PLACR)

32

R/W

0000_0000h

18.2.3/293

F000_3040

32

R/W

0000_0000h

18.2.4/296

Compute Operation Control Register (MCM_CPO)

18.2.1 Crossbar Switch (AXBS) Slave Configuration (MCM_PLASC)
PLASC is a 16-bit read-only register identifying the presence/absence of bus slave
connections to the device’s crossbar switch.
Address: F000_3000h base + 8h offset = F000_3008h
Bit

15

14

13

12

Read

11

10

9

8

7

6

5

4

0

3

2

1

0

0

1

1

1

ASC

Write
Reset

0

0

0

0

0

0

0

0

0

0

0

0

MCM_PLASC field descriptions
Field
15–8
Reserved
7–0
ASC

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
Each bit in the ASC field indicates whether there is a corresponding connection to the crossbar switch's
slave input port.
0
1

A bus slave connection to AXBS input port n is absent
A bus slave connection to AXBS input port n is present

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Chapter 18 Miscellaneous Control Module (MCM)

18.2.2 Crossbar Switch (AXBS) Master Configuration (MCM_PLAMC)
PLAMC is a 16-bit read-only register identifying the presence/absence of bus master
connections to the device's crossbar switch.
Address: F000_3000h base + Ah offset = F000_300Ah
Bit

15

14

13

12

Read

11

10

9

8

7

6

5

4

0

3

2

1

0

1

1

0

1

AMC

Write
Reset

0

0

0

0

0

0

0

0

0

0

0

0

MCM_PLAMC field descriptions
Field
15–8
Reserved
7–0
AMC

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
Each bit in the AMC field indicates whether there is a corresponding connection to the AXBS master input
port.
0
1

A bus master connection to AXBS input port n is absent
A bus master connection to AXBS input port n is present

18.2.3 Platform Control Register (MCM_PLACR)
The PLACR register selects the arbitration policy for the crossbar masters and configures
the flash memory controller.
The speculation buffer and cache in the flash memory controller is configurable via
MCM_PLACR[15:10].
The speculation buffer is enabled only for instructions after reset. It is possible to have
these states for the speculation buffer:
DFCS

EFDS

Description

0

0

Speculation buffer is on for instruction
and off for data.

0

1

Speculation buffer is on for instruction
and on for data.

1

X

Speculation buffer is off.

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The cache in flash controller is enabled and caching both instruction and data type fetches
after reset. It is possible to have these states for the cache:
DFCC

DFCIC

DFCDA

Description

0

0

0

Cache is on for both
instruction and data.

0

0

1

Cache is on for instruction
and off for data.

0

1

0

Cache is off for instruction
and on for data.

0

1

1

Cache is off for both
instruction and data.

1

X

X

Cache is off.

Address: F000_3000h base + Ch offset = F000_300Ch
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

0

R

ESFC
W

Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Bit

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

0

0

0

0
EFDS

DFCC

DFCIC

DFCDA

0

0

0

0

0

W

Reset

0
ARB

CFCC

DFCS

R

0

0

0

0

0

0

0

MCM_PLACR field descriptions
Field
31–17
Reserved
16
ESFC

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
Enable Stalling Flash Controller
This field is used to enable stalling flash controller when flash is busy.
0
1

Disable stalling flash controller when flash is busy.
Enable stalling flash controller when flash is busy.
Table continues on the next page...

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Chapter 18 Miscellaneous Control Module (MCM)

MCM_PLACR field descriptions (continued)
Field
15
DFCS

Description
Disable Flash Controller Speculation
This field is used to disable flash controller speculation.
0
1

14
EFDS

Enable Flash Data Speculation
This field is used to enable flash data speculation.
0
1

13
DFCC

This field is used to disable flash controller cache.

This field is used to disable flash controller instruction caching.

9
ARB

8–0
Reserved

Enable flash controller instruction caching.
Disable flash controller instruction caching.

Disable Flash Controller Data Caching
This field is used to disable flash controller data caching.
0
1

10
CFCC

Enable flash controller cache.
Disable flash controller cache.

Disable Flash Controller Instruction Caching

0
1
11
DFCDA

Disable flash data speculation.
Enable flash data speculation.

Disable Flash Controller Cache

0
1
12
DFCIC

Enable flash controller speculation.
Disable flash controller speculation.

Enable flash controller data caching
Disable flash controller data caching.

Clear Flash Controller Cache
Writing a 1 to this field clears the cache. Writing a 0 to this field is ignored. This field always reads as 0.
Arbitration select
0
1

Fixed-priority arbitration for the crossbar masters
Round-robin arbitration for the crossbar masters

This field is reserved.
This read-only field is reserved and always has the value 0.

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18.2.4 Compute Operation Control Register (MCM_CPO)
This register controls the Compute Operation.
Address: F000_3000h base + 40h offset = F000_3040h
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

0

R

W

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Bit

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

0

0

0

0

0

0
CPOWOI

R

CPOREQ

0

CPOACK

Reset

W

Reset

0

0

0

0

0

0

0

0

0

0

MCM_CPO field descriptions
Field

Description

31–3
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

2
CPOWOI

Compute Operation wakeup on interrupt

1
CPOACK

Compute Operation acknowledge

0
CPOREQ

Compute Operation request

0
1

0
1

No effect.
When set, the CPOREQ is cleared on any interrupt or exception vector fetch.

Compute operation entry has not completed or compute operation exit has completed.
Compute operation entry has completed or compute operation exit has not completed.

This bit is auto-cleared by vector fetching if CPOWOI = 1.
Table continues on the next page...

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Chapter 18 Miscellaneous Control Module (MCM)

MCM_CPO field descriptions (continued)
Field

Description
0
1

Request is cleared.
Request Compute Operation.

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Chapter 19
Micro Trace Buffer (MTB)
19.1 Introduction
Microcontrollers using the Cortex-M0+ processor core include support for a CoreSight
Micro Trace Buffer to provide program trace capabilities. The proper name for this
function is the CoreSight Micro Trace Buffer for the Cortex-M0+ Processor; in this
document, it is simply abbreviated as the MTB.
The simple program trace function creates instruction address change-of-flow data
packets in a user-defined region of the system RAM. Accordingly, the system RAM
controller manages requests from two sources:
• AMBA-AHB reads and writes from the system bus
• program trace packet writes from the processor
As part of the MTB functionality, there is a DWT (Data Watchpoint and Trace) module
that allows the user to define watchpoint addresses, or optionally, an address and data
value, that when triggered, can be used to start or stop the program trace recording.
This document details the functionality of both the MTB_RAM and MTB_DWT
capabilities.

19.1.1 Overview
A generic block diagram of the processor core and platform for this class of ultra low-end
microcontrollers is shown as follows:

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Introduction

Cortex-M0+ Core
Dbg

NVIC

CM0+ Core Platform

Fetch
AGU

Dec

Rn

LD/ST

SHFT
ALU

MUL

AHB Bus

IO Port

MTB Port

32

PRAM

RAM
Array

RGPIO
s1

m0

32

Alt-Master

s2

m3

DMA_4ch

m2

AXBS

BME

PBRIDGE

Slave
Peripherals

s0

32

FMC

NVM
Array

Figure 19-1. Generic Cortex-M0+ core platform block diagram

As shown in the block diagram, the platform RAM (PRAM) controller connects to two
input buses:
• the crossbar slave port for system bus accesses
• a "private execution MTB port" from the core
The logical paths from the crossbar master input ports to the PRAM controller are
highlighted along with the private execution trace port from the processor core. The
private MTB port signals the instruction address information needed for the 64-bit
program trace packets written into the system RAM. The PRAM controller output
interfaces to the attached RAM array. In this document, the PRAM controller is the
MTB_RAM controller.
The following information is taken from the ARM CoreSight Micro Trace Buffer
documentation.
"The execution trace packet consists of a pair of 32-bit words that the MTB generates
when it detects the processor PC value changes non-sequentially. A non-sequential PC
change can occur during branch instructions or during exception entry.
The processor can cause a trace packet to be generated for any instruction.

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Chapter 19 Micro Trace Buffer (MTB)

The following figure shows how the execution trace information is stored in memory as a
sequence of packets.
31

1
Nth destination address
Nth source address

Incrementing
SRAM memory
address

31

1
2nd destination address
2nd source address
1st destination address
1st source address

0
S
A

0
S
A
S
A

Odd word address
Even word address

Start bit
Odd word address
Even word address

Atom bit

Figure 19-2. MTB execution trace storage format

The first, lower addressed, word contains the source of the branch, the address it
branched from. The value stored only records bits[31:1] of the source address, because
Thumb instructions are at least halfword aligned. The least significant bit of the value is
the A-bit. The A-bit indicates the atomic state of the processor at the time of the branch,
and can differentiate whether the branch originated from an instruction in a program, an
exception, or a PC update in Debug state. When it is zero the branch originated from an
instruction, when it is one the branch originated from an exception or PC update in
Debug state. This word is always stored at an even word location.
The second, higher addressed word contains the destination of the branch, the address it
branched to. The value stored only records bits[31:1] of the branch address. The least
significant bit of the value is the S-bit. The S-bit indicates where the trace started. An Sbit value of 1 indicates where the first packet after the trace started and a value of 0 is
used for other packets. Because it is possible to start and stop tracing multiple times in a
trace session, the memory might contain several packets with the S-bit set to 1. This word
is always stored in the next higher word in memory, an odd word address.
When the A-bit is set to 1, the source address field contains the architecturally-preferred
return address for the exception. For example, if an exception was caused by an SVC
instruction, then the source address field contains the address of the following instruction.
This is different from the case where the A-bit is set to 0. In this case, the source address
contains the address of the branch instruction.
For an exception return operation, two packets are generated:
• The first packet has the:
• Source address field set to the address of the instruction that causes the exception
return, BX or POP.

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Introduction

• Destination address field set to bits[31:1] of the EXC_RETURN value. See the
ARM v6-M Architecture Reference Manual.
• The A-bit set to 0.
• The second packet has the:
• Source address field set to bits[31:1] of the EXC_RETURN value.
• Destination address field set to the address of the instruction where execution
commences.
• A-bit set to 1."
Given the recorded change-of-flow trace packets in system RAM and the memory image
of the application, a debugger can read out the data and create an instruction-byinstruction program trace. In keeping with the low area and power implementation cost
design targets, the MTB trace format is less efficient than other CoreSight trace modules,
for example, the ETM (Embedded Trace Macrocell). Since each branch packet is 8 bytes
in size, a 1 KB block of system RAM can contain 128 branches. Using the Dhrystone 2.1
benchmark's dynamic runtime as an example, this corresponds to about 875 instructions
per KB of trace RAM, or with a zero wait state memory, this corresponds to
approximately 1600 processor cycles per KB. This metric is obviously very sensitive to
the runtime characteristics of the user code.
The MTB_DWT function (not shown in the core platform block diagram) monitors the
processor address and data buses so that configurable watchpoints can be detected to
trigger the appropriate response in the MTB recording.

19.1.2 Features
The key features of the MTB_RAM and MTB_DWT include:
• Memory controller for system RAM and Micro Trace Buffer for program trace
packets
• Read/write capabilities for system RAM accesses, write-only for program trace
packets
• Supports zero wait state response to system bus accesses when no trace data is being
written
• Can buffer two AHB address phases and one data write for system RAM accesses
• Supports 64-bit program trace packets including source and destination instruction
addresses
• Program trace information in RAM available to MCU's application code or external
debugger
• Program trace watchpoint configuration accessible by MCU's application code or
debugger
• Location and size of RAM trace buffer is configured by software
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Chapter 19 Micro Trace Buffer (MTB)

• Two DWT comparators (addresses or address + data) provide programmable start/
stop recording
• CoreSight compliant debug functionality

19.1.3 Modes of Operation
The MTB_RAM and MTB_DWT functions do not support any special modes of
operation. The MTB_RAM controller, as a memory-mapped device located on the
platform's slave AHB system bus, responds based strictly on memory addresses for
accesses to its attached RAM array. The MTB private execution bus provides program
trace packet write information to the RAM controller. Both the MTB_RAM and
MTB_DWT modules are memory-mapped so their programming models can be
accessed.
All functionality associated with the MTB_RAM and MTB_DWT modules resides in the
core platform's clock domain; this includes its connections with the RAM array.

19.2 External Signal Description
The MTB_RAM and MTB_DWT modules do not directly support any external
interfaces.
The internal interfaces includes a standard AHB bus with a 32-bit datapath width from
the appropriate crossbar slave port plus the private execution trace bus from the processor
core. The signals in the private execution trace bus are detailed in the following table
taken from the ARM CoreSight Micro Trace Buffer documentation. The signal direction
is defined as viewed by the MTB_RAM controller.
Table 19-1. Private execution trace port from the core to MTB_RAM
Signal

Direction

Description

LOCKUP

Input

Indicates the processor is in the Lockup state. This signal is driven LOW for cycles
when the processor is executing normally and driven HIGH for every cycle the
processor is waiting in the Lockup state. This signal is valid on every cycle.

IAESEQ

Input

Indicates the next instruction address in execute, IAEX, is sequential, that is nonbranching.

IAEXEN

Input

IAEX register enable.

IAEX[30:0]

Input

Registered address of the instruction in the execution stage, shifted right by one
bit, that is, PC >> 1.

ATOMIC

Input

Indicates the processor is performing non-instruction related activities.

EDBGRQ

Output

Request for the processor to enter the Debug state, if enabled, and halt.

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In addition, there are two signals formed by the MTB_DWT module and driven to the
MTB_RAM controller: TSTART (trace start) and TSTOP (trace stop). These signals can
be configured using the trace watchpoints to define programmable addresses and data
values to affect the program trace recording state.

19.3 Memory Map and Register Definition
The MTB_RAM and MTB_DWT modules each support a sparsely-populated 4 KB
address space for their programming models. For each address space, there are a variety
of control and configurable registers near the base address, followed by a large unused
address space and finally a set of CoreSight registers to support dynamic determination of
the debug configuration for the device.
Accesses to the programming model follow standard ARM conventions. Taken from the
ARM CoreSight Micro Trace Buffer documentation, these are:
• Do not attempt to access reserved or unused address locations. Attempting to access
these locations can result in UNPREDICTABLE behavior.
• The behavior of the MTB is UNPREDICTABLE if the registers with UNKNOWN
reset values are not programmed prior to enabling trace.
• Unless otherwise stated in the accompanying text:
• Do not modify reserved register bits
• Ignore reserved register bits on reads
• All register bits are reset to a logic 0 by a system or power-on reset
• Use only word size, 32-bit, transactions to access all registers

19.3.1 MTB_RAM Memory Map
MTB memory map
Absolute
address
(hex)

Register name

Width
Access
(in bits)

Reset value

Section/
page

F000_0000

MTB Position Register (MTB_POSITION)

32

R/W

Undefined

19.31.1/306

F000_0004

MTB Master Register (MTB_MASTER)

32

R/W

0000_0080h

19.31.2/307

F000_0008

MTB Flow Register (MTB_FLOW)

32

R/W

Undefined

19.31.3/309

F000_000C MTB Base Register (MTB_BASE)

32

R

Undefined

19.31.4/310

F000_0F00

32

R

0000_0000h

19.31.5/310

F000_0FA0 Claim TAG Set Register (MTB_TAGSET)

32

R

0000_0000h

19.31.6/311

F000_0FA4 Claim TAG Clear Register (MTB_TAGCLEAR)

32

R

0000_0000h

19.31.7/311

F000_0FB0 Lock Access Register (MTB_LOCKACCESS)

32

R

0000_0000h

19.31.8/312

Integration Mode Control Register (MTB_MODECTRL)

Table continues on the next page...

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Chapter 19 Micro Trace Buffer (MTB)

MTB memory map (continued)
Absolute
address
(hex)

Register name

Width
Access
(in bits)

Reset value

Section/
page

F000_0FB4 Lock Status Register (MTB_LOCKSTAT)

32

R

0000_0000h

19.31.9/312

F000_0FB8 Authentication Status Register (MTB_AUTHSTAT)

32

R

0000_0000h

19.31.10/
313

F000_0FBC Device Architecture Register (MTB_DEVICEARCH)

32

R

4770_0A31h

19.31.11/
314

F000_0FC8 Device Configuration Register (MTB_DEVICECFG)

32

R

0000_0000h

19.31.12/
314

F000_0FCC Device Type Identifier Register (MTB_DEVICETYPID)

32

R

0000_0031h

19.31.13/
315

F000_0FD0 Peripheral ID Register (MTB_PERIPHID4)

32

R

See section

19.31.14/
315

F000_0FD4 Peripheral ID Register (MTB_PERIPHID5)

32

R

See section

19.31.14/
315

F000_0FD8 Peripheral ID Register (MTB_PERIPHID6)

32

R

See section

19.31.14/
315

F000_0FDC Peripheral ID Register (MTB_PERIPHID7)

32

R

See section

19.31.14/
315

F000_0FE0 Peripheral ID Register (MTB_PERIPHID0)

32

R

See section

19.31.14/
315

F000_0FE4 Peripheral ID Register (MTB_PERIPHID1)

32

R

See section

19.31.14/
315

F000_0FE8 Peripheral ID Register (MTB_PERIPHID2)

32

R

See section

19.31.14/
315

F000_0FEC Peripheral ID Register (MTB_PERIPHID3)

32

R

See section

19.31.14/
315

F000_0FF0

Component ID Register (MTB_COMPID0)

32

R

See section

19.31.15/
316

F000_0FF4

Component ID Register (MTB_COMPID1)

32

R

See section

19.31.15/
316

F000_0FF8

Component ID Register (MTB_COMPID2)

32

R

See section

19.31.15/
316

F000_0FFC Component ID Register (MTB_COMPID3)

32

R

See section

19.31.15/
316

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Memory Map and Register Definition

19.31.1 MTB Position Register (MTB_POSITION)
The MTB_POSITION register is the trace write address pointer and wrap bit. This
register can be modified by the explicit programming model writes. It is also
automatically updated by the MTB hardware when trace packets are being recorded.
Address: F000_0000h base + 0h offset = F000_0000h
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

R

POINTER
W

Reset

x*

x*

x*

x*

x*

x*

x*

x*

x*

x*

x*

x*

x*

x*

x*

x*

Bit

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

POINTER
W

Reset

x*

x*

x*

x*

x*

x*

x*

0

WRAP

R

x*

x*

x*

x*

x*

x*

x*

0

0

* Notes:
• x = Undefined at reset.

MTB_POSITION field descriptions
Field
31–3
POINTER

Description
Trace Packet Address Pointer
Trace packet address pointer. Because a packet consists of two words, the POINTER field is the address
of the first word of a packet. This field contains bits[31:3] of the RAM address that points to the next
unused memory location for the trace data. This is an empty ascending location and is automatically
updated.
A debug agent can add the value of POINTER to the value of MTB_BASE to obtain the absolute pointer
address as seen on the system AHB bus interface.
NOTE: The size of the RAM is parameterized and the most significant bits of the POINTER field are
RAZ/WI.
POSITION register bits greater than or equal to 15 are RAZ/WI, therefore, the active POINTER field bits
are [11:0].

2
WRAP
1–0
Reserved

This bit is set to 1 automatically when the POINTER value wraps as determined by the
MTB_MASTER[MASK] bit in the MASTER Trace Control Register. A debug agent can use the WRAP bit
to determine whether the trace information above and below the pointer address is valid.
This field is reserved.
This read-only field is reserved and always has the value 0.

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Chapter 19 Micro Trace Buffer (MTB)

19.31.2 MTB Master Register (MTB_MASTER)
The MTB_MASTER register contains the main program trace enable plus other trace
controls. This register can be modified by the explicit programming model writes.
MTB_MASTER[EN] and MTB_MASTER[HALTREQ] fields are also automatically
updated by the MTB hardware.
Before the MTB_MASTER[EN] or MTB_MASTER[TSTARTEN] bits are set to 1,
software must initialize the MTB_POSITION and MTB_FLOW registers.
If the MTB_FLOW[WATERMARK] field is used to stop tracing or to halt the processor,
the MTB_MASTER[MASK] field must still be set to a value that prevents the
MTB_POSITION[POINTER] field from wrapping before it reaches the
MTB_FLOW[WATERMARK] value.
NOTE
The format of this mask field is different than the
MTBDWT_MASKn[MASK].
Address: F000_0000h base + 4h offset = F000_0004h
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

0

R

EN

Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Bit

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

HALTREQ

RAMPRIV

SFRWPRIV

TSTOPEN

TSTARTEN

W

0

0

1

0

0

0

0

0

R

W

Reset

0

0

0

0

0

0

MASK

0

0

0

MTB_MASTER field descriptions
Field
31
EN

Description
Main trace enable bit
When this bit is 1, trace data is written into the RAM memory location addressed by
MTB_POSITION[POINTER]. The MTB_POSITION[POINTER] value auto increments after the trace data
packet is written.
The EN bit can be automatically set to 0 using the MTB_FLOW[WATERMARK] field and the
MTB_FLOW[AUTOSTOP] bit.
The EN bit is automatically set to 1 if the TSTARTEN bit is 1 and the TSTART signal is HIGH.
The EN bit is automatically set to 0 if TSTOPEN bit is 1 and the TSTOP signal is HIGH.
Table continues on the next page...

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Memory Map and Register Definition

MTB_MASTER field descriptions (continued)
Field

Description
NOTE: If the EN bit is set to 0 because the MTB_FLOW[WATERMARK] field is set, then it is not
automatically set to 1 if the TSTARTEN bit is 1 and the TSTART input is HIGH. In this case,
tracing can only be restarted if the MTB_FLOW[WATERMARK] or MTB_POSITION[POINTER]
value is changed by software.

30–10
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

9
HALTREQ

Halt request bit

8
RAMPRIV

RAM privilege bit

This bit is connected to the halt request signal of the trace logic, EDBGRQ. When HALTREQ is set to 1,
the EDBFGRQ is asserted if DBGEN (invasive debug enable, one of the debug authentication interface
signals) is also HIGH. The HALTREQ bit can be automatically set to 1 using the
MTB_FLOW[WATERMARK] field.

If this bit is 0, then user or privileged AHB read and write accesses to the RAM are permitted. If this bit is
1, then only privileged AHB read and write accesses to the RAM are permitted and user accesses are
RAZ/WI. The HPROT[1] signal determines if an access is a user or privileged mode reference.

7
SFRWPRIV

Special Function Register Write Privilege bit

6
TSTOPEN

Trace stop input enable

5
TSTARTEN

Trace start input enable

4–0
MASK

If this bit is 0, then user or privileged AHB read and write accesses to the MTB_RAM Special Function
Registers (programming model) are permitted. If this bit is 1, then only privileged write accesses are
permitted; user write accesses are ignored. The HPROT[1] signal determines if an access is user or
privileged. Note MTB_RAM SFR read access are not controlled by this bit and are always permitted.

If this bit is 1 and the TSTOP signal is HIGH, then the EN bit is set to 0. If a trace packet is being written to
memory, the write is completed before tracing is stopped.

If this bit is 1 and the TSTART signal is HIGH, then the EN bit is set to 1. Tracing continues until a stop
condition occurs.
Mask
This value determines the maximum size of the trace buffer in RAM. It specifies the most-significant bit of
the MTB_POSITION[POINTER] field that can be updated by automatic increment. If the trace tries to
advance past this power of two, the MTB_POSITION[WRAP] bit is set to 1, the
MTB_POSITION[POINTER[MASK:0]] bits are set to zero, and the MTB_POSITION[POINTER[11:MASK
+1]] bits remain unchanged.
This field causes the trace packet information to be stored in a circular buffer of size 2^[MASK+4] bytes,
that can be positioned in memory at multiples of this size. Valid values of this field are zero to 11. Values
greater than the maximum have the same effect as the maximum.

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Chapter 19 Micro Trace Buffer (MTB)

19.31.3 MTB Flow Register (MTB_FLOW)
The MTB_FLOW register contains the watermark address and the autostop/autohalt
control bits.
Address: F000_0000h base + 8h offset = F000_0008h
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

R

WATERMARK

Reset

x*

x*

x*

x*

x*

x*

x*

x*

x*

x*

x*

x*

x*

x*

x*

x*

Bit

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

AUTOHALT

AUTOSTOP

W

0

x*

x*

R

WATERMARK
W

Reset

x*

x*

x*

x*

x*

x*

x*

x*

x*

x*

x*

x*

x*

* Notes:
• x = Undefined at reset.

MTB_FLOW field descriptions
Field
31–3
WATERMARK

2
Reserved

Description
WATERMARK value
This field contains an address in the same format as the MTB_POSITION[POINTER] field. When the
MTB_POSITION[POINTER] matches the WATERMARK field value, actions defined by the AUTOHALT
and AUTOSTOP bits are performed.
This field is reserved.
This read-only field is reserved and always has the value 0.

1
AUTOHALT

If this bit is 1 and WATERMARK is equal to MTB_POSITION[POINTER], then the
MTB_MASTER[HALTREQ] bit is automatically set to 1. If the DBGEN signal is HIGH, the MTB asserts this
halt request to the Cortex-M0+ processor by asserting the EDBGRQ signal.

0
AUTOSTOP

If this bit is 1 and WATERMARK is equal to MTB_POSITION[POINTER], then the MTB_MASTER[EN] bit
is automatically set to 0. This stops tracing.

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Memory Map and Register Definition

19.31.4 MTB Base Register (MTB_BASE)
The read-only MTB_BASE Register indicates where the RAM is located in the processor
memory map. This register is provided to enable auto discovery of the MTB RAM
location, by a debug agent and is defined by a hardware design parameter. For these
devices, the base address is defined by the expression: MTB_BASE[BASEADDR] =
0x2000_0000 - (RAM_Size/4)
Address: F000_0000h base + Ch offset = F000_000Ch
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

BASEADDR

R
W
Reset

x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x*

* Notes:
• x = Undefined at reset.

MTB_BASE field descriptions
Field

Description

31–0
BASEADDR

This value is defined with a hardwired signal and the expression: 0x2000_0000 - (RAM_Size/4). For
example, if the total RAM capacity is 16 KB, this field is 0x1FFF_F000.

19.31.5 Integration Mode Control Register (MTB_MODECTRL)
This register enables the device to switch from a functional mode, or default behavior,
into integration mode. It is hardwired to specific values used during the auto-discovery
process by an external debug agent.
Address: F000_0000h base + F00h offset = F000_0F00h
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

MODECTRL

R
W
Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

MTB_MODECTRL field descriptions
Field
31–0
MODECTRL

Description
Hardwired to 0x0000_0000

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Chapter 19 Micro Trace Buffer (MTB)

19.31.6 Claim TAG Set Register (MTB_TAGSET)
The Claim Tag Set Register returns the number of bits that can be set on a read, and
enables individual bits to be set on a write. It is hardwired to specific values used during
the auto-discovery process by an external debug agent.
Address: F000_0000h base + FA0h offset = F000_0FA0h
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

TAGSET

R
W
Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

MTB_TAGSET field descriptions
Field

Description

31–0
TAGSET

Hardwired to 0x0000_0000

19.31.7 Claim TAG Clear Register (MTB_TAGCLEAR)
The read/write Claim Tag Clear Register is used to read the claim status on debug
resources. A read indicates the claim tag status. Writing 1 to a specific bit clears the
corresponding claim tag to 0. It is hardwired to specific values used during the autodiscovery process by an external debug agent.
Address: F000_0000h base + FA4h offset = F000_0FA4h
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

TAGCLEAR

R
W
Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

MTB_TAGCLEAR field descriptions
Field
31–0
TAGCLEAR

Description
Hardwired to 0x0000_0000

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Memory Map and Register Definition

19.31.8 Lock Access Register (MTB_LOCKACCESS)
The Lock Access Register enables a write access to component registers. It is hardwired
to specific values used during the auto-discovery process by an external debug agent.
Address: F000_0000h base + FB0h offset = F000_0FB0h
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

LOCKACCESS

R
W
Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

MTB_LOCKACCESS field descriptions
Field

Description

31–0
LOCKACCESS

Hardwired to 0x0000_0000

19.31.9 Lock Status Register (MTB_LOCKSTAT)
The Lock Status Register indicates the status of the lock control mechanism. This register
is used in conjunction with the Lock Access Register. It is hardwired to specific values
used during the auto-discovery process by an external debug agent.
Address: F000_0000h base + FB4h offset = F000_0FB4h
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

LOCKSTAT

R
W
Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

MTB_LOCKSTAT field descriptions
Field
31–0
LOCKSTAT

Description
Hardwired to 0x0000_0000

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Chapter 19 Micro Trace Buffer (MTB)

19.31.10 Authentication Status Register (MTB_AUTHSTAT)
The Authentication Status Register reports the required security level and current status
of the security enable bit pairs. Where functionality changes on a given security level,
this change must be reported in this register. It is connected to specific signals used
during the auto-discovery process by an external debug agent.
MTB_AUTHSTAT[3:2] indicates if nonsecure, noninvasive debug is enabled or
disabled, while MTB_AUTHSTAT[1:0] indicates the enabled/disabled state of
nonsecure, invasive debug. For both 2-bit fields, 0b10 indicates the functionality is
disabled and 0b11 indicates it is enabled.
Address: F000_0000h base + FB8h offset = F000_0FB8h
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

0

R
W

Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Bit

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

1

BIT2

1

BIT0

0

0

0

0

0

R
W

Reset

0

0

0

0

0

0

0

0

0

0

0

0

MTB_AUTHSTAT field descriptions
Field

Description

31–4
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

3
Reserved

This read-only field is reserved and always has the value 1.

2
BIT2
1
Reserved
0
BIT0

Connected to NIDEN or DBGEN signal.
This read-only field is reserved and always has the value 1.
Connected to DBGEN.

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Memory Map and Register Definition

19.31.11 Device Architecture Register (MTB_DEVICEARCH)
This register indicates the device architecture. It is hardwired to specific values used
during the auto-discovery process by an external debug agent.
Address: F000_0000h base + FBCh offset = F000_0FBCh
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

0

1

0

1

0

0

0

1

1

0

0

0

1

DEVICEARCH

R
W
Reset

0

1

0

0

0

1

1

1

0

1

1

1

0

0

0

0

0

0

MTB_DEVICEARCH field descriptions
Field

Description

31–0
DEVICEARCH

Hardwired to 0x4770_0A31.

19.31.12 Device Configuration Register (MTB_DEVICECFG)
This register indicates the device configuration. It is hardwired to specific values used
during the auto-discovery process by an external debug agent.
Address: F000_0000h base + FC8h offset = F000_0FC8h
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

DEVICECFG

R
W
Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

MTB_DEVICECFG field descriptions
Field
31–0
DEVICECFG

Description
Hardwired to 0x0000_0000.

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Chapter 19 Micro Trace Buffer (MTB)

19.31.13 Device Type Identifier Register (MTB_DEVICETYPID)
This register indicates the device type ID. It is hardwired to specific values used during
the auto-discovery process by an external debug agent.
Address: F000_0000h base + FCCh offset = F000_0FCCh
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

0

0

0

0

0

0

0

1

1

0

0

0

1

DEVICETYPID

R
W
Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

MTB_DEVICETYPID field descriptions
Field

Description

31–0
DEVICETYPID

Hardwired to 0x0000_0031.

19.31.14 Peripheral ID Register (MTB_PERIPHIDn)
These registers indicate the peripheral IDs. They are hardwired to specific values used
during the auto-discovery process by an external debug agent.
Address: F000_0000h base + FD0h offset + (4d × i), where i=0d to 7d
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

PERIPHID

R
W
Reset

x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x*

* Notes:
• See field descriptions for the reset values.x = Undefined at reset.

MTB_PERIPHIDn field descriptions
Field
31–0
PERIPHID

Description
Peripheral ID4 is hardwired to 0x0000_0004; ID0 to 0x0000_0032; ID1 to 0x0000_00B9; ID2 to
0x0000_000B; and all the others to 0x0000_0000.

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Memory Map and Register Definition

19.31.15 Component ID Register (MTB_COMPIDn)
These registers indicate the component IDs. They are hardwired to specific values used
during the auto-discovery process by an external debug agent.
Address: F000_0000h base + FF0h offset + (4d × i), where i=0d to 3d
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

COMPID

R
W
Reset

x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x*

* Notes:
• See field descriptions for the reset values.x = Undefined at reset.

MTB_COMPIDn field descriptions
Field
31–0
COMPID

Description
Component ID
Component ID0 is hardwired to 0x0000_000D; ID1 to 0x0000_0090; ID2 to 0x0000_0005; ID3 to
0x0000_00B1.

19.3.2 MTB_DWT Memory Map
The MTB_DWT programming model supports a very simplified subset of the v7M debug
architecture and follows the standard ARM DWT definition.
MTBDWT memory map
Absolute
address
(hex)

Register name

Width
Access
(in bits)

Reset value

Section/
page

F000_1000

MTB DWT Control Register (MTBDWT_CTRL)

32

R

2F00_0000h 19.32.1/317

F000_1020

MTB_DWT Comparator Register (MTBDWT_COMP0)

32

R/W

0000_0000h

19.32.2/318

F000_1024

MTB_DWT Comparator Mask Register (MTBDWT_MASK0)

32

R/W

0000_0000h

19.32.3/319

F000_1028

MTB_DWT Comparator Function Register 0
(MTBDWT_FCT0)

32

R/W

0000_0000h

19.32.4/320

F000_1030

MTB_DWT Comparator Register (MTBDWT_COMP1)

32

R/W

0000_0000h

19.32.2/318

F000_1034

MTB_DWT Comparator Mask Register (MTBDWT_MASK1)

32

R/W

0000_0000h

19.32.3/319

F000_1038

MTB_DWT Comparator Function Register 1
(MTBDWT_FCT1)

32

R/W

0000_0000h

19.32.5/322

F000_1200

MTB_DWT Trace Buffer Control Register
(MTBDWT_TBCTRL)

32

R/W

2000_0000h

19.32.6/323

F000_1FC8 Device Configuration Register (MTBDWT_DEVICECFG)

32

R

0000_0000h

19.32.7/325

Table continues on the next page...

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Chapter 19 Micro Trace Buffer (MTB)

MTBDWT memory map (continued)
Absolute
address
(hex)

Width
Access
(in bits)

Register name

Reset value

Section/
page

F000_1FCC Device Type Identifier Register (MTBDWT_DEVICETYPID)

32

R

0000_0004h

19.32.8/325

F000_1FD0 Peripheral ID Register (MTBDWT_PERIPHID4)

32

R

See section

19.32.9/326

F000_1FD4 Peripheral ID Register (MTBDWT_PERIPHID5)

32

R

See section

19.32.9/326

F000_1FD8 Peripheral ID Register (MTBDWT_PERIPHID6)

32

R

See section

19.32.9/326

F000_1FDC Peripheral ID Register (MTBDWT_PERIPHID7)

32

R

See section

19.32.9/326

F000_1FE0 Peripheral ID Register (MTBDWT_PERIPHID0)

32

R

See section

19.32.9/326

F000_1FE4 Peripheral ID Register (MTBDWT_PERIPHID1)

32

R

See section

19.32.9/326

F000_1FE8 Peripheral ID Register (MTBDWT_PERIPHID2)

32

R

See section

19.32.9/326

F000_1FEC Peripheral ID Register (MTBDWT_PERIPHID3)

32

R

See section

19.32.9/326

F000_1FF0

Component ID Register (MTBDWT_COMPID0)

32

R

See section

19.32.10/
326

F000_1FF4

Component ID Register (MTBDWT_COMPID1)

32

R

See section

19.32.10/
326

F000_1FF8

Component ID Register (MTBDWT_COMPID2)

32

R

See section

19.32.10/
326

F000_1FFC Component ID Register (MTBDWT_COMPID3)

32

R

See section

19.32.10/
326

19.32.1 MTB DWT Control Register (MTBDWT_CTRL)
The MTBDWT_CTRL register provides read-only information on the watchpoint
configuration for the MTB_DWT.
Address: F000_1000h base + 0h offset = F000_1000h
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

NUMCMP

R

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

0

0

0

0

0

0

0

0

0

0

0

DWTCFGCTRL

W
Reset

0

0

1

0

1

1

1

1

0

0

0

0

0

0

0

0

0

0

0

0

MTBDWT_CTRL field descriptions
Field
31–28
NUMCMP

Description
Number of comparators
The MTB_DWT implements two comparators.

27–0
DWT configuration controls
DWTCFGCTRL
This field is hardwired to 0xF00_0000, disabling all the remaining DWT functionality. The specific fields
and their state are:
MTBDWT_CTRL[27] = NOTRCPKT = 1, trace sample and exception trace is not supported
Table continues on the next page...

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Memory Map and Register Definition

MTBDWT_CTRL field descriptions (continued)
Field

Description
MTBDWT_CTRL[26] = NOEXTTRIG = 1, external match signals are not supported
MTBDWT_CTRL[25] = NOCYCCNT = 1, cycle counter is not supported
MTBDWT_CTRL[24] = NOPRFCNT = 1, profiling counters are not supported
MTBDWT_CTRL[22] = CYCEBTENA = 0, no POSTCNT underflow packets generated
MTBDWT_CTRL[21] = FOLDEVTENA = 0, no folded instruction counter overflow events
MTBDWT_CTRL[20] = LSUEVTENA = 0, no LSU counter overflow events
MTBDWT_CTRL[19] = SLEEPEVTENA = 0, no sleep counter overflow events
MTBDWT_CTRL[18] = EXCEVTENA = 0, no exception overhead counter events
MTBDWT_CTRL[17] = CPIEVTENA = 0, no CPI counter overflow events
MTBDWT_CTRL[16] = EXCTRCENA = 0, generation of exception trace disabled
MTBDWT_CTRL[12] = PCSAMPLENA = 0, no periodic PC sample packets generated
MTBDWT_CTRL[11:10] = SYNCTAP = 0, no synchronization packets
MTBDWT_CTRL[9] = CYCTAP = 0, cycle counter is not supported
MTBDWT_CTRL[8:5] = POSTINIT = 0, cycle counter is not supported
MTBDWT_CTRL[4:1] = POSTPRESET = 0, cycle counter is not supported
MTBDWT_CTRL[0] = CYCCNTENA = 0, cycle counter is not supported

19.32.2 MTB_DWT Comparator Register (MTBDWT_COMPn)
The MTBDWT_COMPn registers provide the reference value for comparator n.
Address: F000_1000h base + 20h offset + (16d × i), where i=0d to 1d
Bit
R
W

31

Reset

0

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

COMP
0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

MTBDWT_COMPn field descriptions
Field
31–0
COMP

Description
Reference value for comparison
If MTBDWT_COMP0 is used for a data value comparator and the access size is byte or halfword, the data
value must be replicated across all appropriate byte lanes of this register. For example, if the data is a
byte-sized "x" value, then COMP[31:24] = COMP[23:16] = COMP[15:8] = COMP[7:0] = "x". Likewise, if the
data is a halfword-size "y" value, then COMP[31:16] = COMP[15:0] = "y".

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Chapter 19 Micro Trace Buffer (MTB)

19.32.3 MTB_DWT Comparator Mask Register
(MTBDWT_MASKn)
The MTBDWT_MASKn registers define the size of the ignore mask applied to the
reference address for address range matching by comparator n. Note the format of this
mask field is different than the MTB_MASTER[MASK].
Address: F000_1000h base + 24h offset + (16d × i), where i=0d to 1d
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

3

0

R

0

0

0

0

0

0

0

0

0

0

0

0

0

0

1

0

0

0

MASK

W
Reset

2

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

MTBDWT_MASKn field descriptions
Field
31–5
Reserved
4–0
MASK

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
MASK
The value of the ignore mask, 0-31 bits, is applied to address range matching. MASK = 0 is used to
include all bits of the address in the comparison, except if MASK = 0 and the comparator is configured to
watch instruction fetch addresses, address bit [0] is ignored by the hardware since all fetches must be at
least halfword aligned. For MASK != 0 and regardless of watch type, address bits [x-1:0] are ignored in the
address comparison.
Using a mask means the comparator matches on a range of addresses, defined by the unmasked most
significant bits of the address, bits [31:x]. The maximum MASK value is 24, producing a 16 Mbyte mask.
An attempted write of a MASK value > 24 is limited by the MTBDWT hardware to 24.
If MTBDWT_COMP0 is used as a data value comparator, then MTBDWT_MASK0 should be programmed
to zero.

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Memory Map and Register Definition

19.32.4 MTB_DWT Comparator Function Register 0
(MTBDWT_FCT0)
The MTBDWT_FCTn registers control the operation of comparator n.
Address: F000_1000h base + 28h offset = F000_1028h
31

30

29

28

27

26

25

0

R

24

23

22

MATCHED

Bit

21

20

19

18

0

17

16

0

W

Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Bit

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

DATAVADDR0

DATAVSIZE

W

Reset

0

0

0

0

0

0

0

0

DATAVMATCH

0

R

0

FUNCTION

0

0

0

0

0

0

0

0

MTBDWT_FCT0 field descriptions
Field
31–25
Reserved
24
MATCHED

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
Comparator match
If this read-only flag is asserted, it indicates the operation defined by the FUNCTION field occurred since
the last read of the register. Reading the register clears this bit.
Table continues on the next page...

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Chapter 19 Micro Trace Buffer (MTB)

MTBDWT_FCT0 field descriptions (continued)
Field

Description
0
1

No match.
Match occurred.

23–20
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

19–16
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

15–12
DATAVADDR0

Data Value Address 0
Since the MTB_DWT implements two comparators, the DATAVADDR0 field is restricted to values {0,1}.
When the DATAVMATCH bit is asserted, this field defines the comparator number to use for linked
address comparison.
If MTBDWT_COMP0 is used as a data watchpoint and MTBDWT_COMP1 as an address watchpoint,
DATAVADDR0 must be set.

11–10
DATAVSIZE

Data Value Size
For data value matching, this field defines the size of the required data comparison.
00
01
10
11

9
Reserved
8
DATAVMATCH

This field is reserved.
This read-only field is reserved and always has the value 0.
Data Value Match
The assertion of this bit enables data value comparison. For this implementation, MTBDWT_COMP0
supports address or data value comparisons; MTBDWT_COMP1 only supports address comparisons.
0
1

7–4
Reserved
3–0
FUNCTION

Byte.
Halfword.
Word.
Reserved. Any attempts to use this value results in UNPREDICTABLE behavior.

Perform address comparison.
Perform data value comparison.

This field is reserved.
This read-only field is reserved and always has the value 0.
Function
Selects the action taken on a comparator match. If MTBDWT_COMP0 is used for a data value and
MTBDWT_COMP1 for an address value, then MTBDWT_FCT1[FUNCTION] must be set to zero. For this
configuration, MTBDWT_MASK1 can be set to a non-zero value, so the combined comparators match on
a range of addresses.
0000
0100
0101
0110
0111
others

Disabled.
Instruction fetch.
Data operand read.
Data operand write.
Data operand (read + write).
Reserved. Any attempts to use this value results in UNPREDICTABLE behavior.

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Memory Map and Register Definition

19.32.5 MTB_DWT Comparator Function Register 1
(MTBDWT_FCT1)
The MTBDWT_FCTn registers control the operation of comparator n. Since the
MTB_DWT only supports data value comparisons on comparator 0, there are several
fields in the MTBDWT_FCT1 register that are RAZ/WI (bits 12, 11:10, 8).
Address: F000_1000h base + 38h offset = F000_1038h
31

30

29

28

27

26

25

0

R

24

23

22

21

20

MATCHED

Bit

19

18

17

16

0

W

Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Bit

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

R

FUNCTION
W

Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

MTBDWT_FCT1 field descriptions
Field
31–25
Reserved
24
MATCHED

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
Comparator match
If this read-only flag is asserted, it indicates the operation defined by the FUNCTION field occurred since
the last read of the register. Reading the register clears this bit.
Table continues on the next page...

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Chapter 19 Micro Trace Buffer (MTB)

MTBDWT_FCT1 field descriptions (continued)
Field

Description
0
1

23–4
Reserved

No match.
Match occurred.

This field is reserved.
This read-only field is reserved and always has the value 0.

3–0
FUNCTION

Function
Selects the action taken on a comparator match. If MTBDWT_COMP0 is used for a data value and
MTBDWT_COMP1 for an address value, then MTBDWT_FCT1[FUNCTION] must be set to zero. For this
configuration, MTBDWT_MASK1 can be set to a non-zero value, so the combined comparators match on
a range of addresses.
0000
0100
0101
0110
0111
others

Disabled.
Instruction fetch.
Data operand read.
Data operand write.
Data operand (read + write).
Reserved. Any attempts to use this value results in UNPREDICTABLE behavior.

19.32.6 MTB_DWT Trace Buffer Control Register
(MTBDWT_TBCTRL)
The MTBDWT_TBCTRL register defines how the watchpoint comparisons control the
actual trace buffer operation.
Recall the MTB supports starting and stopping the program trace based on the watchpoint
comparisons signaled via TSTART and TSTOP. The watchpoint comparison signals are
enabled in the MTB's control logic by setting the appropriate enable bits,
MTB_MASTER[TSTARTEN, TSTOPEN]. In the event of simultaneous assertion of
both TSTART and TSTOP, TSTART takes priority.
Address: F000_1000h base + 200h offset = F000_1200h
Bit

31

30

29

28

27

26

25

24

23

22

NUMCOMP

R

21

20

19

18

17

16

0

0

0

0

0

0

0

W

Reset

0

0

1

0

0

0

0

0

0

0

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15

14

13

12

11

10

9

8

7

6

5

4

3

2

0

0

0

0

0

0

0

1

0

ACOMP0

Bit

ACOMP1

Memory Map and Register Definition

0

0

0

R

W

Reset

0

0

0

0

0

0

0

MTBDWT_TBCTRL field descriptions
Field
31–28
NUMCOMP

Description
Number of Comparators
This read-only field specifies the number of comparators in the MTB_DWT. This implementation includes
two registers.

27–2
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

1
ACOMP1

Action based on Comparator 1 match
When the MTBDWT_FCT1[MATCHED] is set, it indicates MTBDWT_COMP1 address compare has
triggered and the trace buffer's recording state is changed.
0
1

0
ACOMP0

Trigger TSTOP based on the assertion of MTBDWT_FCT1[MATCHED].
Trigger TSTART based on the assertion of MTBDWT_FCT1[MATCHED].

Action based on Comparator 0 match
When the MTBDWT_FCT0[MATCHED] is set, it indicates MTBDWT_COMP0 address compare has
triggered and the trace buffer's recording state is changed. The assertion of MTBDWT_FCT0[MATCHED]
is caused by the following conditions:
• Address match in MTBDWT_COMP0 when MTBDWT_FCT0[DATAVMATCH] = 0
• Data match in MTBDWT_COMP0 when MTBDWT_FCT0[DATAVMATCH, DATAVADDR0] = {1,0}
• Data match in MTBDWT_COMP0 and address match in MTBDWT_COMP1 when
MTBDWT_FCT0[DATAVMATCH, DATAVADDR0] = {1,1}
0
1

Trigger TSTOP based on the assertion of MTBDWT_FCT0[MATCHED].
Trigger TSTART based on the assertion of MTBDWT_FCT0[MATCHED].

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Chapter 19 Micro Trace Buffer (MTB)

19.32.7 Device Configuration Register (MTBDWT_DEVICECFG)
This register indicates the device configuration. It is hardwired to specific values used
during the auto-discovery process by an external debug agent.
Address: F000_1000h base + FC8h offset = F000_1FC8h
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

DEVICECFG

R
W
Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

MTBDWT_DEVICECFG field descriptions
Field

Description

31–0
DEVICECFG

Hardwired to 0x0000_0000.

19.32.8 Device Type Identifier Register (MTBDWT_DEVICETYPID)
This register indicates the device type ID. It is hardwired to specific values used during
the auto-discovery process by an external debug agent.
Address: F000_1000h base + FCCh offset = F000_1FCCh
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

0

0

0

0

0

0

0

0

0

0

1

0

0

DEVICETYPID

R
W
Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

MTBDWT_DEVICETYPID field descriptions
Field
31–0
DEVICETYPID

Description
Hardwired to 0x0000_0004.

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Memory Map and Register Definition

19.32.9 Peripheral ID Register (MTBDWT_PERIPHIDn)
These registers indicate the peripheral IDs. They are hardwired to specific values used
during the auto-discovery process by an external debug agent.
Address: F000_1000h base + FD0h offset + (4d × i), where i=0d to 7d
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

PERIPHID

R
W
Reset

x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x*

* Notes:
• See field descriptions for the reset values. x = Undefined at reset.

MTBDWT_PERIPHIDn field descriptions
Field

Description

31–0
PERIPHID

Peripheral ID1 is hardwired to 0x0000_00E0; ID2 to 0x0000_0008; and all the others to 0x0000_0000.

19.32.10 Component ID Register (MTBDWT_COMPIDn)
These registers indicate the component IDs. They are hardwired to specific values used
during the auto-discovery process by an external debug agent.
Address: F000_1000h base + FF0h offset + (4d × i), where i=0d to 3d
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

COMPID

R
W
Reset

x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x*

* Notes:
• See field descriptions for the reset values.x = Undefined at reset.

MTBDWT_COMPIDn field descriptions
Field
31–0
COMPID

Description
Component ID
Component ID0 is hardwired to 0x0000_000D; ID1 to 0x0000_0090; ID2 to 0x0000_0005; ID3 to
0x0000_00B1.

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Chapter 19 Micro Trace Buffer (MTB)

19.3.3 System ROM Memory Map
The System ROM Table registers are also mapped into a sparsely-populated 4 KB
address space.
For core configurations like that supported by Cortex-M0+, ARM recommends that a
debugger identifies and connects to the debug components using the CoreSight debug
infrastructure.
ARM recommends that a debugger follows the flow as shown in the following figure to
discover the components in the CoreSight debug infrastructure. In this case a debugger
reads the peripheral and component ID registers for each CoreSight component in the
CoreSight system.

Figure 19-56. CoreSight discovery process
ROM memory map
Absolute
address
(hex)

Register name

Width
Access
(in bits)

Reset value

Section/
page

F000_2000

Entry (ROM_ENTRY0)

32

R

See section

19.33.1/328

F000_2004

Entry (ROM_ENTRY1)

32

R

See section

19.33.1/328

F000_2008

Entry (ROM_ENTRY2)

32

R

See section

19.33.1/328

F000_200C End of Table Marker Register (ROM_TABLEMARK)

32

R

0000_0000h

19.33.2/329

F000_2FCC System Access Register (ROM_SYSACCESS)

32

R

0000_0001h

19.33.3/329

F000_2FD0 Peripheral ID Register (ROM_PERIPHID4)

32

R

See section

19.33.4/330

F000_2FD4 Peripheral ID Register (ROM_PERIPHID5)

32

R

See section

19.33.4/330

F000_2FD8 Peripheral ID Register (ROM_PERIPHID6)

32

R

See section

19.33.4/330

Table continues on the next page...

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Memory Map and Register Definition

ROM memory map (continued)
Absolute
address
(hex)

Width
Access
(in bits)

Register name

Reset value

Section/
page

F000_2FDC Peripheral ID Register (ROM_PERIPHID7)

32

R

See section

19.33.4/330

F000_2FE0 Peripheral ID Register (ROM_PERIPHID0)

32

R

See section

19.33.4/330

F000_2FE4 Peripheral ID Register (ROM_PERIPHID1)

32

R

See section

19.33.4/330

F000_2FE8 Peripheral ID Register (ROM_PERIPHID2)

32

R

See section

19.33.4/330

F000_2FEC Peripheral ID Register (ROM_PERIPHID3)

32

R

See section

19.33.4/330

F000_2FF0

Component ID Register (ROM_COMPID0)

32

R

See section

19.33.5/330

F000_2FF4

Component ID Register (ROM_COMPID1)

32

R

See section

19.33.5/330

F000_2FF8

Component ID Register (ROM_COMPID2)

32

R

See section

19.33.5/330

F000_2FFC Component ID Register (ROM_COMPID3)

32

R

See section

19.33.5/330

19.33.1 Entry (ROM_ENTRYn)
The System ROM Table begins with "n" relative 32-bit addresses, one for each debug
component present in the device and terminating with an all-zero value signaling the end
of the table at the "n+1"-th value.
NOTE
See Chip Configuration chapter for the debug components these
registers point to.
It is hardwired to specific values used during the auto-discovery process by an external
debug agent.
Address: F000_2000h base + 0h offset + (4d × i), where i=0d to 2d
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

ENTRY

R
W
Reset

x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x*

* Notes:
• See field descriptions for reset values.x = Undefined at reset.

ROM_ENTRYn field descriptions
Field
31–0
ENTRY

Description
ENTRY
Entry 0 (MTB) is hardwired to 0xFFFF_E003; Entry 1 (MTBDWT) to 0xFFFF_F003; Entry 2 (CM0+ ROM
Table) to 0xF00F_D003.

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Chapter 19 Micro Trace Buffer (MTB)

19.33.2 End of Table Marker Register (ROM_TABLEMARK)
This register indicates end of table marker. It is hardwired to specific values used during
the auto-discovery process by an external debug agent.
Address: F000_2000h base + Ch offset = F000_200Ch
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

MARK

R
W
Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

ROM_TABLEMARK field descriptions
Field

Description

31–0
MARK

Hardwired to 0x0000_0000

19.33.3 System Access Register (ROM_SYSACCESS)
This register indicates system access. It is hardwired to specific values used during the
auto-discovery process by an external debug agent.
Address: F000_2000h base + FCCh offset = F000_2FCCh
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

0

0

0

0

0

0

0

0

0

0

0

0

1

SYSACCESS

R
W
Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

ROM_SYSACCESS field descriptions
Field
31–0
SYSACCESS

Description
Hardwired to 0x0000_0001

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Memory Map and Register Definition

19.33.4 Peripheral ID Register (ROM_PERIPHIDn)
These registers indicate the peripheral IDs. They are hardwired to specific values used
during the auto-discovery process by an external debug agent.
Address: F000_2000h base + FD0h offset + (4d × i), where i=0d to 7d
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

PERIPHID

R
W
Reset

x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x*

* Notes:
• See field descriptions for reset values.x = Undefined at reset.

ROM_PERIPHIDn field descriptions
Field

Description

31–0
PERIPHID

Peripheral ID1 is hardwired to 0x0000_00E0; ID2 to 0x0000_0008; and all the others to 0x0000_0000.

19.33.5 Component ID Register (ROM_COMPIDn)
These registers indicate the component IDs. They are hardwired to specific values used
during the auto-discovery process by an external debug agent.
Address: F000_2000h base + FF0h offset + (4d × i), where i=0d to 3d
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

COMPID

R
W
Reset

x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x*

* Notes:
• See field descriptions for reset values.x = Undefined at reset.

ROM_COMPIDn field descriptions
Field
31–0
COMPID

Description
Component ID
Component ID0 is hardwired to 0x0000_000D; ID1 to 0x0000_0010; ID2 to 0x0000_0005; ID3 to
0x0000_00B1.

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Chapter 20
Crossbar Switch Lite (AXBS-Lite)
20.1 Introduction
NOTE
For the chip-specific implementation details of this module's
instances see the chip configuration information.
This chapter provides information on the layout, configuration, and programming of the
crossbar switch. The crossbar switch connects bus masters and bus slaves using a
crossbar switch structure. This structure allows up to four bus masters to access different
bus slaves simultaneously, while providing arbitration among the bus masters when they
access the same slave.

20.1.1 Features
The crossbar switch includes these features:
• Symmetric crossbar bus switch implementation
• Allows concurrent accesses from different masters to different slaves
• 32-bit data bus
• Operation at a 1-to-1 clock frequency with the bus masters
• Programmable configuration for fixed-priority or round-robin slave port arbitration

20.2 Memory Map / Register Definition
This crossbar switch is designed for minimal gate count. It, therefore, has no memorymapped configuration registers.

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Functional Description

20.3 Functional Description
20.3.1 General operation
When a master accesses the crossbar switch the access is immediately taken. If the
targeted slave port of the access is available, then the access is immediately presented on
the slave port. Single-clock or zero-wait-state accesses are possible through the crossbar.
If the targeted slave port of the access is busy or parked on a different master port, the
requesting master simply sees wait states inserted until the targeted slave port can service
the master's request. The latency in servicing the request depends on each master's
priority level and the responding slave's access time.
Because the crossbar switch appears to be just another slave to the master device, the
master device has no knowledge of whether it actually owns the slave port it is targeting.
While the master does not have control of the slave port it is targeting, it simply waits.
A master is given control of the targeted slave port only after a previous access to a
different slave port completes, regardless of its priority on the newly targeted slave port.
This prevents deadlock from occurring when:
• A higher priority master has:
• An outstanding request to one slave port that has a long response time and
• A pending access to a different slave port, and
• A lower priority master is also making a request to the same slave port as the pending
access of the higher priority master.
After the master has control of the slave port it is targeting, the master remains in control
of the slave port until it relinquishes the slave port by running an IDLE cycle or by
targeting a different slave port for its next access.
The master can also lose control of the slave port if another higher-priority master makes
a request to the slave port.
The crossbar terminates all master IDLE transfers, as opposed to allowing the termination
to come from one of the slave buses. Additionally, when no master is requesting access to
a slave port, the crossbar drives IDLE transfers onto the slave bus, even though a default
master may be granted access to the slave port.
When a slave bus is being idled by the crossbar, it remains parked with the last master to
use the slave port. This is done to save the initial clock of arbitration delay that otherwise
would be seen if the master had to arbitrate to gain control of the slave port.

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Chapter 20 Crossbar Switch Lite (AXBS-Lite)

20.3.2 Arbitration
The crossbar switch supports two arbitration algorithms:
• Fixed priority
• Round robin
The selection of the global slave port arbitration is controlled by MCM_PLACR[ARB].
For fixed priority, set ARB to 0. For round robin, set ARB to 1. This arbitration setting
applies to all slave ports.

20.3.2.1 Arbitration During Undefined Length Bursts
All lengths of burst accesses lock out arbitration until the last beat of the burst.

20.3.2.2 Fixed-priority operation
When operating in fixed-priority mode, each master is assigned a unique priority level
with the highest numbered master having the highest priority (master 1 has lower priority
than master 3). If two masters request access to the same slave port, the master with the
highest priority gains control over the slave port.
NOTE
In this arbitration mode, a higher-priority master can
monopolize a slave port, preventing accesses from any lowerpriority master to the port.
When a master makes a request to a slave port, the slave port checks whether the new
requesting master's priority level is higher than that of the master that currently has
control over the slave port, unless the slave port is in a parked state. The slave port
performs an arbitration check at every clock edge to ensure that the proper master, if any,
has control of the slave port.
The following table describes possible scenarios based on the requesting master port:

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Initialization/application information

Table 20-1. How AXBS grants control of a slave port to a master
When

Then AXBS grants control to the requesting master

Both of the following are true:
At the next clock edge
• The current master is not running a transfer.
• The new requesting master's priority level is higher than
that of the current master.
The requesting master's priority level is lower than the current At the conclusion of one of the following cycles:
master.
• An IDLE cycle
• A non-IDLE cycle to a location other than the current
slave port

20.3.2.3 Round-robin priority operation
When operating in round-robin mode, each master is assigned a relative priority based on
the master port number. This relative priority is compared to the master port number (ID)
of the last master to perform a transfer on the slave bus. The highest priority requesting
master becomes owner of the slave bus at the next transfer boundary. Priority is based on
how far ahead the ID of the requesting master is to the ID of the last master.
After granted access to a slave port, a master may perform as many transfers as desired to
that port until another master makes a request to the same slave port. The next master in
line is granted access to the slave port at the next transfer boundary, or possibly on the
next clock cycle if the current master has no pending access request.
As an example of arbitration in round-robin mode, assume the crossbar is implemented
with master ports 0, 1, 4, and 5. If the last master of the slave port was master 1, and
master 0, 4 and 5 make simultaneous requests, they are serviced in the order 4, 5, and
then 0.
The round-robin arbitration mode generally provides a more fair allocation of the
available slave-port bandwidth (compared to fixed priority) as the fixed master priority
does not affect the master selection.

20.4 Initialization/application information
No initialization is required for the crossbar switch. See the AXBS section of the
configuration chapter for the reset state of the arbitration scheme.

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Chapter 21
Peripheral Bridge (AIPS-Lite)
21.1 Introduction
NOTE
For the chip-specific implementation details of this module's
instances see the chip configuration information.
The peripheral bridge converts the crossbar switch interface to an interface that can
access most of the slave peripherals on this chip.
The peripheral bridge supports up to 128 peripherals, each with a 4K-byte address space.
(Not all peripheral slots might be used. See the chip configuration chapter and memory
map chapter for details on slot assignment.) The bridge includes separate clock enable
inputs for each of the slots to accommodate slower peripherals.

21.1.1 Features
Key features of the peripheral bridge are:
• Supports peripheral slots with 8-, 16-, and 32-bit datapath width
• Dedicated clock enables for independently configurable peripherals allow each on- or
off-platform peripheral to operate at any integer-divisible speed less than or equal to
the system clock frequency.

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Functional description

21.1.2 General operation
The slave devices connected to the peripheral bridge are modules which contain a
programming model of control and status registers. The system masters read and write
these registers through the peripheral bridge. The peripheral bridge performs a bus
protocol conversion of the master transactions and generates the following as inputs to
the peripherals:
• Module enables
• Module addresses
• Transfer attributes
• Byte enables
• Write data
The peripheral bridge selects and captures read data from the peripheral interface and
returns it to the crossbar switch.
The register maps of the peripherals are located on 4-KB boundaries. Each peripheral is
allocated one or more 4-KB block(s) of the memory map.
The AIPS-Lite module uses the accessed peripheral's data width to perform proper data
byte lane routing; bus decomposition (bus sizing) is performed when the access size is
larger than the peripheral's data width.

21.2 Functional description
The peripheral bridge functions as a bus protocol translator between the crossbar switch
and the slave peripheral bus.
The peripheral bridge manages all transactions destined for the attached slave devices and
generates select signals for modules on the peripheral bus by decoding accesses within
the attached address space.
By default, reads and writes on the crossbar side of the peripheral bridge take two dataphase cycles. On the IPS side, accesses complete in one cycle. If wait states are inserted
by the slave peripheral, access time will be extended accordingly.

21.2.1 Access support
All combinations of access size and peripheral data port width are supported. An access
that is larger than the target peripheral's data width will be decomposed to multiple,
smaller accesses. Bus decomposition is terminated by a transfer error caused by an access
to an empty register area.
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Chapter 22
Direct Memory Access Multiplexer (DMAMUX)
22.1 Introduction
NOTE
For the chip-specific implementation details of this module's
instances see the chip configuration information.

22.1.1 Overview
The direct memory access multiplexer (DMAMUX) routes DMA sources, called slots, to
any of the 4 DMA channels. This process is illustrated in the following figure.

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Introduction
DMAMUX

Source #1

DMA channel #0
DMA channel #1

Source #2
Source #3

Source #x
Always #1

Always #y
Trigger #1

DMA channel #n
Trigger #z

Figure 22-1. DMAMUX block diagram

22.1.2 Features
The DMAMUX module provides these features:
• 63 peripheral slots and 6 always-on slots can be routed to 4 channels.
• 4 independently selectable DMA channel routers.
• The first 2 channels additionally provide a trigger functionality.
• Each channel router can be assigned to one of the 63 possible peripheral DMA slots
or to one of the 6 always-on slots.

22.1.3 Modes of operation
The following operating modes are available:
• Disabled mode
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Chapter 22 Direct Memory Access Multiplexer (DMAMUX)

In this mode, the DMA channel is disabled. Because disabling and enabling of DMA
channels is done primarily via the DMA configuration registers, this mode is used
mainly as the reset state for a DMA channel in the DMA channel MUX. It may also
be used to temporarily suspend a DMA channel while reconfiguration of the system
takes place, for example, changing the period of a DMA trigger.
• Normal mode
In this mode, a DMA source is routed directly to the specified DMA channel. The
operation of the DMAMUX in this mode is completely transparent to the system.
• Periodic Trigger mode
In this mode, a DMA source may only request a DMA transfer, such as when a
transmit buffer becomes empty or a receive buffer becomes full, periodically.
Configuration of the period is done in the registers of the periodic interrupt timer
(PIT). This mode is available only for channels 0–1.

22.2 External signal description
The DMAMUX has no external pins.

22.3 Memory map/register definition
This section provides a detailed description of all memory-mapped registers in the
DMAMUX.
DMAMUX memory map
Absolute
address
(hex)

Register name

Width
Access
(in bits)

Reset value

Section/
page

4002_1000

Channel Configuration register (DMAMUX0_CHCFG0)

8

R/W

00h

22.3.1/339

4002_1001

Channel Configuration register (DMAMUX0_CHCFG1)

8

R/W

00h

22.3.1/339

4002_1002

Channel Configuration register (DMAMUX0_CHCFG2)

8

R/W

00h

22.3.1/339

4002_1003

Channel Configuration register (DMAMUX0_CHCFG3)

8

R/W

00h

22.3.1/339

22.3.1 Channel Configuration register (DMAMUXx_CHCFGn)
Each of the DMA channels can be independently enabled/disabled and associated with
one of the DMA slots (peripheral slots or always-on slots) in the system.
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Functional description

NOTE
Setting multiple CHCFG registers with the same Source value
will result in unpredictable behavior.
NOTE
Before changing the trigger or source settings a DMA channel
must be disabled via the CHCFGn[ENBL] bit.
Address: 4002_1000h base + 0h offset + (1d × i), where i=0d to 3d
Bit

Read
Write
Reset

7

6

ENBL

TRIG

5

0

0

4

3

2

1

0

0

0

0

SOURCE
0

0

0

DMAMUXx_CHCFGn field descriptions
Field
7
ENBL

Description
DMA Channel Enable
Enables the DMA channel.
0

1
6
TRIG

DMA Channel Trigger Enable
Enables the periodic trigger capability for the triggered DMA channel.
0
1

5–0
SOURCE

DMA channel is disabled. This mode is primarily used during configuration of the DMA Mux. The DMA
has separate channel enables/disables, which should be used to disable or re-configure a DMA
channel.
DMA channel is enabled

Triggering is disabled. If triggering is disabled, and the ENBL bit is set, the DMA Channel will simply
route the specified source to the DMA channel. (Normal mode)
Triggering is enabled. If triggering is enabled, and the ENBL bit is set, the DMAMUX is in Periodic
Trigger mode.

DMA Channel Source (Slot)
Specifies which DMA source, if any, is routed to a particular DMA channel. See your device's chip
configuration details for further details about the peripherals and their slot numbers.

22.4 Functional description
The primary purpose of the DMAMUX is to provide flexibility in the system's use of the
available DMA channels. As such, configuration of the DMAMUX is intended to be a
static procedure done during execution of the system boot code. However, if the
procedure outlined in Enabling and configuring sources is followed, the configuration of
the DMAMUX may be changed during the normal operation of the system.
Functionally, the DMAMUX channels may be divided into two classes:

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Chapter 22 Direct Memory Access Multiplexer (DMAMUX)

• Channels which implement the normal routing functionality plus periodic triggering
capability
• Channels which implement only the normal routing functionality

22.4.1 DMA channels with periodic triggering capability
Besides the normal routing functionality, the first 2 channels of the DMAMUX provide a
special periodic triggering capability that can be used to provide an automatic mechanism
to transmit bytes, frames, or packets at fixed intervals without the need for processor
intervention. The trigger is generated by the periodic interrupt timer (PIT); as such, the
configuration of the periodic triggering interval is done via configuration registers in the
PIT. See the section on periodic interrupt timer for more information on this topic.
Note
Because of the dynamic nature of the system (due to DMA
channel priorities, bus arbitration, interrupt service routine
lengths, etc.), the number of clock cycles between a trigger and
the actual DMA transfer cannot be guaranteed.

Source #1
Source #2
Source #3
Trigger #1
Trigger #2

DMA channel #0
DMA channel #1

Source #x
Trigger #4

Always #1

DMA channel #3

Always #y

Figure 22-12. DMAMUX triggered channels
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Functional description

The DMA channel triggering capability allows the system to schedule regular DMA
transfers, usually on the transmit side of certain peripherals, without the intervention of
the processor. This trigger works by gating the request from the peripheral to the DMA
until a trigger event has been seen. This is illustrated in the following figure.
Peripheral request

Trigger

DMA request

Figure 22-13. DMAMUX channel triggering: normal operation

After the DMA request has been serviced, the peripheral will negate its request,
effectively resetting the gating mechanism until the peripheral re-asserts its request AND
the next trigger event is seen. This means that if a trigger is seen, but the peripheral is not
requesting a transfer, then that trigger will be ignored. This situation is illustrated in the
following figure.
Peripheral request

Trigger
DMA request

Figure 22-14. DMAMUX channel triggering: ignored trigger

This triggering capability may be used with any peripheral that supports DMA transfers,
and is most useful for two types of situations:
• Periodically polling external devices on a particular bus
As an example, the transmit side of an SPI is assigned to a DMA channel with a
trigger, as described above. After it has been set up, the SPI will request DMA
transfers, presumably from memory, as long as its transmit buffer is empty. By using
a trigger on this channel, the SPI transfers can be automatically performed every 5μs
(as an example). On the receive side of the SPI, the SPI and DMA can be configured
to transfer receive data into memory, effectively implementing a method to
periodically read data from external devices and transfer the results into memory
without processor intervention.
• Using the GPIO ports to drive or sample waveforms

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Chapter 22 Direct Memory Access Multiplexer (DMAMUX)

By configuring the DMA to transfer data to one or more GPIO ports, it is possible to
create complex waveforms using tabular data stored in on-chip memory. Conversely,
using the DMA to periodically transfer data from one or more GPIO ports, it is
possible to sample complex waveforms and store the results in tabular form in onchip memory.
A more detailed description of the capability of each trigger, including resolution, range
of values, and so on, may be found in the periodic interrupt timer section.

22.4.2 DMA channels with no triggering capability
The other channels of the DMAMUX provide the normal routing functionality as
described in Modes of operation.

22.4.3 Always-enabled DMA sources
In addition to the peripherals that can be used as DMA sources, there are 6 additional
DMA sources that are always enabled. Unlike the peripheral DMA sources, where the
peripheral controls the flow of data during DMA transfers, the sources that are always
enabled provide no such "throttling" of the data transfers. These sources are most useful
in the following cases:
• Performing DMA transfers to/from GPIO—Moving data from/to one or more GPIO
pins, either unthrottled (that is as fast as possible), or periodically (using the DMA
triggering capability).
• Performing DMA transfers from memory to memory—Moving data from memory to
memory, typically as fast as possible, sometimes with software activation.
• Performing DMA transfers from memory to the external bus, or vice-versa—Similar
to memory to memory transfers, this is typically done as quickly as possible.
• Any DMA transfer that requires software activation—Any DMA transfer that should
be explicitly started by software.
In cases where software should initiate the start of a DMA transfer, an always-enabled
DMA source can be used to provide maximum flexibility. When activating a DMA
channel via software, subsequent executions of the minor loop require that a new start
event be sent. This can either be a new software activation, or a transfer request from the
DMA channel MUX. The options for doing this are:
• Transfer all data in a single minor loop.
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Initialization/application information

By configuring the DMA to transfer all of the data in a single minor loop (that is,
major loop counter = 1), no reactivation of the channel is necessary. The
disadvantage to this option is the reduced granularity in determining the load that the
DMA transfer will impose on the system. For this option, the DMA channel must be
disabled in the DMA channel MUX.
• Use explicit software reactivation.
In this option, the DMA is configured to transfer the data using both minor and major
loops, but the processor is required to reactivate the channel by writing to the DMA
registers after every minor loop. For this option, the DMA channel must be disabled
in the DMA channel MUX.
• Use an always-enabled DMA source.
In this option, the DMA is configured to transfer the data using both minor and major
loops, and the DMA channel MUX does the channel reactivation. For this option, the
DMA channel should be enabled and pointing to an "always enabled" source. Note
that the reactivation of the channel can be continuous (DMA triggering is disabled)
or can use the DMA triggering capability. In this manner, it is possible to execute
periodic transfers of packets of data from one source to another, without processor
intervention.

22.5 Initialization/application information
This section provides instructions for initializing the DMA channel MUX.

22.5.1 Reset
The reset state of each individual bit is shown in Memory map/register definition. In
summary, after reset, all channels are disabled and must be explicitly enabled before use.

22.5.2 Enabling and configuring sources
To enable a source with periodic triggering:
1. Determine with which DMA channel the source will be associated. Note that only the
first 2 DMA channels have periodic triggering capability.
2. Clear the CHCFG[ENBL] and CHCFG[TRIG] fields of the DMA channel.

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Chapter 22 Direct Memory Access Multiplexer (DMAMUX)

3. Ensure that the DMA channel is properly configured in the DMA. The DMA channel
may be enabled at this point.
4. Configure the corresponding timer.
5. Select the source to be routed to the DMA channel. Write to the corresponding
CHCFG register, ensuring that the CHCFG[ENBL] and CHCFG[TRIG] fields are
set.
NOTE
The following is an example. See chip configuration section for
the number of this device's DMA channels that have triggering
capability.
To configure source #5 transmit for use with DMA channel 2, with periodic triggering
capability:
1. Write 0x00 to CHCFG2 (base address + 0x02).
2. Configure channel 2 in the DMA, including enabling the channel.
3. Configure a timer for the desired trigger interval.
4. Write 0xC5 to CHCFG2 (base address + 0x02).
The following code example illustrates steps 1 and 4 above:
In File registers.h:
#define DMAMUX_BASE_ADDR
0xFC084000/* Example only
/* Following example assumes char is 8-bits */
volatile unsigned char *CHCONFIG0 = (volatile unsigned
volatile unsigned char *CHCONFIG1 = (volatile unsigned
volatile unsigned char *CHCONFIG2 = (volatile unsigned
volatile unsigned char *CHCONFIG3 = (volatile unsigned
volatile unsigned char *CHCONFIG4 = (volatile unsigned
volatile unsigned char *CHCONFIG5 = (volatile unsigned
volatile unsigned char *CHCONFIG6 = (volatile unsigned
volatile unsigned char *CHCONFIG7 = (volatile unsigned
volatile unsigned char *CHCONFIG8 = (volatile unsigned
volatile unsigned char *CHCONFIG9 = (volatile unsigned
volatile unsigned char *CHCONFIG10= (volatile unsigned
volatile unsigned char *CHCONFIG11= (volatile unsigned
volatile unsigned char *CHCONFIG12= (volatile unsigned
volatile unsigned char *CHCONFIG13= (volatile unsigned
volatile unsigned char *CHCONFIG14= (volatile unsigned
volatile unsigned char *CHCONFIG15= (volatile unsigned

! */
char
char
char
char
char
char
char
char
char
char
char
char
char
char
char
char

*)
*)
*)
*)
*)
*)
*)
*)
*)
*)
*)
*)
*)
*)
*)
*)

(DMAMUX_BASE_ADDR+0x0000);
(DMAMUX_BASE_ADDR+0x0001);
(DMAMUX_BASE_ADDR+0x0002);
(DMAMUX_BASE_ADDR+0x0003);
(DMAMUX_BASE_ADDR+0x0004);
(DMAMUX_BASE_ADDR+0x0005);
(DMAMUX_BASE_ADDR+0x0006);
(DMAMUX_BASE_ADDR+0x0007);
(DMAMUX_BASE_ADDR+0x0008);
(DMAMUX_BASE_ADDR+0x0009);
(DMAMUX_BASE_ADDR+0x000A);
(DMAMUX_BASE_ADDR+0x000B);
(DMAMUX_BASE_ADDR+0x000C);
(DMAMUX_BASE_ADDR+0x000D);
(DMAMUX_BASE_ADDR+0x000E);
(DMAMUX_BASE_ADDR+0x000F);

In File main.c:
#include "registers.h"
:
:
*CHCONFIG2 = 0x00;
*CHCONFIG2 = 0xC5;

To enable a source without periodic triggering:
1. Determine with which DMA channel the source will be associated. Note that only the
first 2 DMA channels have periodic triggering capability.
2. Clear the CHCFG[ENBL] and CHCFG[TRIG] fields of the DMA channel.

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3. Ensure that the DMA channel is properly configured in the DMA. The DMA channel
may be enabled at this point.
4. Select the source to be routed to the DMA channel. Write to the corresponding
CHCFG register, ensuring that CHCFG[ENBL] is set while CHCFG[TRIG] is
cleared.
NOTE
The following is an example. See chip configuration section for
the number of this device's DMA channels that have triggering
capability.
To configure source #5 transmit for use with DMA channel 2, with no periodic triggering
capability:
1. Write 0x00 to CHCFG2 (base address + 0x02).
2. Configure channel 2 in the DMA, including enabling the channel.
3. Write 0x85 to CHCFG2 (base address + 0x02).
The following code example illustrates steps 1 and 3 above:
In File registers.h:
#define DMAMUX_BASE_ADDR
0xFC084000/* Example only
/* Following example assumes char is 8-bits */
volatile unsigned char *CHCONFIG0 = (volatile unsigned
volatile unsigned char *CHCONFIG1 = (volatile unsigned
volatile unsigned char *CHCONFIG2 = (volatile unsigned
volatile unsigned char *CHCONFIG3 = (volatile unsigned
volatile unsigned char *CHCONFIG4 = (volatile unsigned
volatile unsigned char *CHCONFIG5 = (volatile unsigned
volatile unsigned char *CHCONFIG6 = (volatile unsigned
volatile unsigned char *CHCONFIG7 = (volatile unsigned
volatile unsigned char *CHCONFIG8 = (volatile unsigned
volatile unsigned char *CHCONFIG9 = (volatile unsigned
volatile unsigned char *CHCONFIG10= (volatile unsigned
volatile unsigned char *CHCONFIG11= (volatile unsigned
volatile unsigned char *CHCONFIG12= (volatile unsigned
volatile unsigned char *CHCONFIG13= (volatile unsigned
volatile unsigned char *CHCONFIG14= (volatile unsigned
volatile unsigned char *CHCONFIG15= (volatile unsigned

! */
char
char
char
char
char
char
char
char
char
char
char
char
char
char
char
char

*)
*)
*)
*)
*)
*)
*)
*)
*)
*)
*)
*)
*)
*)
*)
*)

(DMAMUX_BASE_ADDR+0x0000);
(DMAMUX_BASE_ADDR+0x0001);
(DMAMUX_BASE_ADDR+0x0002);
(DMAMUX_BASE_ADDR+0x0003);
(DMAMUX_BASE_ADDR+0x0004);
(DMAMUX_BASE_ADDR+0x0005);
(DMAMUX_BASE_ADDR+0x0006);
(DMAMUX_BASE_ADDR+0x0007);
(DMAMUX_BASE_ADDR+0x0008);
(DMAMUX_BASE_ADDR+0x0009);
(DMAMUX_BASE_ADDR+0x000A);
(DMAMUX_BASE_ADDR+0x000B);
(DMAMUX_BASE_ADDR+0x000C);
(DMAMUX_BASE_ADDR+0x000D);
(DMAMUX_BASE_ADDR+0x000E);
(DMAMUX_BASE_ADDR+0x000F);

In File main.c:
#include "registers.h"
:
:
*CHCONFIG2 = 0x00;
*CHCONFIG2 = 0x85;

To disable a source:
A particular DMA source may be disabled by not writing the corresponding source value
into any of the CHCFG registers. Additionally, some module-specific configuration may
be necessary. See the appropriate section for more details.
To switch the source of a DMA channel:

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1. Disable the DMA channel in the DMA and re-configure the channel for the new
source.
2. Clear the CHCFG[ENBL] and CHCFG[TRIG] bits of the DMA channel.
3. Select the source to be routed to the DMA channel. Write to the corresponding
CHCFG register, ensuring that the CHCFG[ENBL] and CHCFG[TRIG] fields are
set.
To switch DMA channel 8 from source #5 transmit to source #7 transmit:
1. In the DMA configuration registers, disable DMA channel 8 and reconfigure it to
handle the transfers to peripheral slot 7. This example assumes channel 8 doesn't
have triggering capability.
2. Write 0x00 to CHCFG8 (base address + 0x08).
3. Write 0x87 to CHCFG8 (base address + 0x08). (In this example, setting
CHCFG[TRIG] would have no effect, due to the assumption that channel 8 does not
support the periodic triggering functionality).
The following code example illustrates steps 2 and 3 above:
In File registers.h:
#define DMAMUX_BASE_ADDR
0xFC084000/* Example only
/* Following example assumes char is 8-bits */
volatile unsigned char *CHCONFIG0 = (volatile unsigned
volatile unsigned char *CHCONFIG1 = (volatile unsigned
volatile unsigned char *CHCONFIG2 = (volatile unsigned
volatile unsigned char *CHCONFIG3 = (volatile unsigned
volatile unsigned char *CHCONFIG4 = (volatile unsigned
volatile unsigned char *CHCONFIG5 = (volatile unsigned
volatile unsigned char *CHCONFIG6 = (volatile unsigned
volatile unsigned char *CHCONFIG7 = (volatile unsigned
volatile unsigned char *CHCONFIG8 = (volatile unsigned
volatile unsigned char *CHCONFIG9 = (volatile unsigned
volatile unsigned char *CHCONFIG10= (volatile unsigned
volatile unsigned char *CHCONFIG11= (volatile unsigned
volatile unsigned char *CHCONFIG12= (volatile unsigned
volatile unsigned char *CHCONFIG13= (volatile unsigned
volatile unsigned char *CHCONFIG14= (volatile unsigned
volatile unsigned char *CHCONFIG15= (volatile unsigned

! */
char
char
char
char
char
char
char
char
char
char
char
char
char
char
char
char

*)
*)
*)
*)
*)
*)
*)
*)
*)
*)
*)
*)
*)
*)
*)
*)

(DMAMUX_BASE_ADDR+0x0000);
(DMAMUX_BASE_ADDR+0x0001);
(DMAMUX_BASE_ADDR+0x0002);
(DMAMUX_BASE_ADDR+0x0003);
(DMAMUX_BASE_ADDR+0x0004);
(DMAMUX_BASE_ADDR+0x0005);
(DMAMUX_BASE_ADDR+0x0006);
(DMAMUX_BASE_ADDR+0x0007);
(DMAMUX_BASE_ADDR+0x0008);
(DMAMUX_BASE_ADDR+0x0009);
(DMAMUX_BASE_ADDR+0x000A);
(DMAMUX_BASE_ADDR+0x000B);
(DMAMUX_BASE_ADDR+0x000C);
(DMAMUX_BASE_ADDR+0x000D);
(DMAMUX_BASE_ADDR+0x000E);
(DMAMUX_BASE_ADDR+0x000F);

In File main.c:
#include "registers.h"
:
:
*CHCONFIG8 = 0x00;
*CHCONFIG8 = 0x87;

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Chapter 23
DMA Controller Module
23.1 Introduction
NOTE
For the chip-specific implementation details of this module's
instances see the chip configuration information.
This chapter describes the direct memory access (DMA) controller module. It provides an
overview of the module and describes in detail its signals and programming model. The
latter sections of this chapter describe operations, features, and supported data transfer
modes in detail.
Note
The designation n is used throughout this section to refer to
registers or signals associated with one of the four identical
DMA channels: DMA0, DMA1, DMA2, or DMA3.

23.1.1 Overview
The DMA controller module enables fast transfers of data, providing an efficient way to
move blocks of data with minimal processor interaction. The DMA module, shown in the
following figure, has four channels that allow 8-bit, 16-bit, or 32-bit data transfers. Each
channel has a dedicated source address register (SARn), destination address register
(DARn), status register (DSRn), byte count register (BCRn), and control register
(DCRn). Collectively, the combined program-visible registers associated with each
channel define a transfer control descriptor (TCD). All transfers are dual address, moving
data from a source memory location to a destination memory location with the module
operating as a 32-bit bus master connected to the system bus. The programming model is
accessed through a 32-bit connection with the slave peripheral bus. DMA data transfers
may be explicitly initiated by software or by peripheral hardware requests.
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The following figure is a simplified block diagram of the 4-channel DMA controller.
DREQ3
DREQ0
DREQ1
DREQ2
DACK0
DACK1
DACK2
DACK3

Channel 0 Channel 1 Channel 2 Channel 3
Slave
Peripheral Bus

SAR0

SAR1

SAR2

SAR3

DAR0

DAR1

DAR2

DAR3

DSR0

DSR1

DSR2

DSR3

BCR0

BCR1

BCR2

BCR3

DCR0

DCR1

DCR2

DCR3

Channel
Requests

Channel
Attributes

Channel
Enables

System Bus Address

MUX
MUX
Control

SysBus Interface
Data Path
Read Data Bus

Interrupts

System Bus Size
Current Master Attributes

Arbitraton/
Control
Data Path
Control

SysBus Interface
Addr + Attr
Registered Addr
Phase Bus Signals

Write Data Bus

Figure 23-1. 4-Channel DMA Block Diagram

The terms peripheral request and DREQ refer to a DMA request from one of the on-chip
peripherals or package pins. The DMA provides hardware handshake signals: either a
DMA acknowledge (DACK) or a done indicator back to the peripheral.

23.1.2 Features
The DMA controller module features:
• Four independently programmable DMA controller channels
• Dual-address transfers via 32-bit master connection to the system bus
• Data transfers in 8-, 16-, or 32-bit blocks

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• Continuous-mode or cycle-steal transfers from software or peripheral initiation
• Automatic hardware acknowledge/done indicator from each channel
• Independent source and destination address registers
• Optional modulo addressing and automatic updates of source and destination
addresses
• Independent transfer sizes for source and destination
• Optional auto-alignment feature for source or destination accesses
• Optional automatic single or double channel linking
• Programming model accessed via 32-bit slave peripheral bus
• Channel arbitration on transfer boundaries using fixed priority scheme

23.2 DMA Transfer Overview
The DMA module can move data within system memory (including memory and
peripheral devices) with minimal processor intervention, greatly improving overall
system performance. The DMA module consists of four independent, functionally
equivalent channels, so references to DMA in this chapter apply to any of the channels. It
is not possible to address all four channels at once.
As soon as a channel has been initialized, it may be started by setting DCRn[START] or
a properly-selected peripheral DMA request, depending on the status of DCRn[ERQ].
The DMA controller supports dual-address transfers using its bus master connection to
the system bus. The DMA channels support transfers up to 32 data bits in size and have
the same memory map addressibility as the processor.
• Dual-address transfers—A dual-address transfer consists of a read followed by a
write and is initiated by a request using the DCRn[START] bit or by a peripheral
DMA request. The read data is temporarily held in the DMA channel hardware until
the write operation. Two types of single transfers occur: a read from a source address
followed by a write to a destination address. See the following figure.

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Memory Map and Registers

Control and Data
Read

Memory/
Peripheral

DMA
Write
Control and Data

Memory/
Peripheral

Figure 23-2. Dual-Address Transfer

Any operation involving a DMA channel follows the same three steps:
1. Channel initialization—The transfer control descriptor, contained in the channel
registers, is loaded with address pointers, a byte-transfer count, and control
information using accesses from the slave peripheral bus.
2. Data transfer—The DMA accepts requests for data transfers. Upon receipt of a
request, it provides address and bus control for the transfers via its master connection
to the system bus and temporary storage for the read data. The channel performs one
or more source read and destination write data transfers.
3. Channel termination—Occurs after the operation is finished successfully or due to an
error. The channel indicates the operation status in the channel's DSR, described in
the definitions of the DMA Status Registers (DSRn) and Byte Count Registers
(BCRn).

23.3 Memory Map and Registers
Descriptions of each register and its bit assignments follow. Modifying DMA control
registers during a transfer can result in undefined operation. The following table shows
the mapping of DMA controller registers. The DMA programming model is accessed via
the slave peripheral bus. The concatenation of the source and destination address
registers, the status and byte count register, and the control register create a 128-bit
transfer control descriptor (TCD) that defines the operation of each DMA channel.

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DMA memory map
Absolute
address
(hex)

Width
Access
(in bits)

Register name

Reset value

Section/
page

4000_8100

Source Address Register (DMA_SAR0)

32

R/W

0000_0000h

23.3.1/353

4000_8104

Destination Address Register (DMA_DAR0)

32

R/W

0000_0000h

23.3.2/354

4000_8108

DMA Status Register / Byte Count Register
(DMA_DSR_BCR0)

32

R/W

0000_0000h

23.3.3/355

4000_810C

DMA Control Register (DMA_DCR0)

32

R/W

0000_0000h

23.3.4/357

4000_8110

Source Address Register (DMA_SAR1)

32

R/W

0000_0000h

23.3.1/353

4000_8114

Destination Address Register (DMA_DAR1)

32

R/W

0000_0000h

23.3.2/354

4000_8118

DMA Status Register / Byte Count Register
(DMA_DSR_BCR1)

32

R/W

0000_0000h

23.3.3/355

4000_811C

DMA Control Register (DMA_DCR1)

32

R/W

0000_0000h

23.3.4/357

4000_8120

Source Address Register (DMA_SAR2)

32

R/W

0000_0000h

23.3.1/353

4000_8124

Destination Address Register (DMA_DAR2)

32

R/W

0000_0000h

23.3.2/354

4000_8128

DMA Status Register / Byte Count Register
(DMA_DSR_BCR2)

32

R/W

0000_0000h

23.3.3/355

4000_812C

DMA Control Register (DMA_DCR2)

32

R/W

0000_0000h

23.3.4/357

4000_8130

Source Address Register (DMA_SAR3)

32

R/W

0000_0000h

23.3.1/353

4000_8134

Destination Address Register (DMA_DAR3)

32

R/W

0000_0000h

23.3.2/354

4000_8138

DMA Status Register / Byte Count Register
(DMA_DSR_BCR3)

32

R/W

0000_0000h

23.3.3/355

4000_813C

DMA Control Register (DMA_DCR3)

32

R/W

0000_0000h

23.3.4/357

23.3.1 Source Address Register (DMA_SARn)
Restriction
For this register:
• Only 32-bit writes are allowed. 16-bit and 8-bit writes
result in a bus error.
• Only four values are allowed to be written to bits 31-20 of
this register. A write of any other value to these bits causes
a configuration error when the channel starts to execute.
For more information about the configuration error, see the
description of the CE field of DSR.
Address: 4000_8000h base + 100h offset + (16d × i), where i=0d to 3d
Bit
R
W

31

Reset

0

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

SAR
0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

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DMA_SARn field descriptions
Field

Description

31–0
SAR

Each SAR contains the byte address used by the DMA controller to read data. The SARn is typically
aligned on a 0-modulo-ssize boundary—that is, on the natural alignment of the source data.
Restriction: Bits 31-20 of this register must be written with one of only four allowed values. Each of
these four allowed values corresponds to a valid region of the device's memory map. The
allowed values are:
• 0x000x_xxxx
• 0x1FFx_xxxx
• 0x200x_xxxx
• 0x400x_xxxx
After being written with one of the allowed values, bits 31-20 read back as the written value.
After being written with any other value, bits 31-20 read back as an indeterminate value.

23.3.2 Destination Address Register (DMA_DARn)
Restriction
For this register:
• Only 32-bit writes are allowed. 16-bit and 8-bit writes
result in a bus error.
• Only four values are allowed to be written to bits 31-20 of
this register. A write of any other value to these bits causes
a configuration error when the channel starts to execute.
For more information about the configuration error, see the
description of the CE field of DSR.
Address: 4000_8000h base + 104h offset + (16d × i), where i=0d to 3d
Bit
R
W

31

Reset

0

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

DAR
0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

DMA_DARn field descriptions
Field
31–0
DAR

Description
Each DAR contains the byte address used by the DMA controller to write data. The DARn is typically
aligned on a 0-modulo-dsize boundary—that is, on the natural alignment of the destination data.
Restriction: Bits 31-20 of this register must be written with one of only four allowed values. Each of
these four allowed values corresponds to a valid region of the device's memory map. The
allowed values are:
• 0x000x_xxxx
• 0x1FFx_xxxx
• 0x200x_xxxx
• 0x400x_xxxx

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DMA_DARn field descriptions (continued)
Field

Description
After being written with one of the allowed values, bits 31-20 read back as the written value.
After being written with any other value, bits 31-20 read back as an indeterminate value.

23.3.3 DMA Status Register / Byte Count Register (DMA_DSR_BCRn)
DSR and BCR are two logical registers that occupy one 32-bit address. DSRn occupies
bits 31–24, and BCRn occupies bits 23–0. DSRn contains flags indicating the channel
status, and BCRn contains the number of bytes yet to be transferred for a given block.
On the successful completion of the write transfer, BCRn decrements by 1, 2, or 4 for 8bit, 16-bit, or 32-bit accesses, respectively. BCRn is cleared if a 1 is written to
DSR[DONE].
In response to an event, the DMA controller writes to the appropriate DSRn bit. Only a
write to DSRn[DONE] results in action. DSRn[DONE] is set when the block transfer is
complete.
When a transfer sequence is initiated and BCRn[BCR] is not a multiple of 4 or 2 when
the DMA is configured for 32-bit or 16-bit transfers, respectively, DSRn[CE] is set and
no transfer occurs.
Bit

31

30

29

28

27

26

25

24

R

0

CE

BES

BED

0

REQ

BSY

DONE

Address: 4000_8000h base + 108h offset + (16d × i), where i=0d to 3d
23

22

21

20

19

18

17

16

BCR

w1c

W

Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Bit

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

0

0

0

0

0

0

0

R

BCR
W

Reset

0

0

0

0

0

0

0

0

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DMA_DSR_BCRn field descriptions
Field
31
Reserved
30
CE

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
Configuration error
Any of the following conditions causes a configuration error:
• BCR, SAR, or DAR does not match the requested transfer size.
• A value greater than 0F_FFFFh is written to BCR.
• Bits 31-20 of SAR or DAR are written with a value other than one of the allowed values. See SAR
and DAR.
• SSIZE or DSIZE is set to an unsupported value.
• BCR equals 0 when the DMA receives a start condition.
CE is cleared at hardware reset or by writing a 1 to the DONE bit.
0
1

29
BES

Bus error on source
BES is cleared at hardware reset or by writing a 1 to the DONE bit.
0
1

28
BED

No bus error occurred.
The DMA channel terminated with a bus error during the read portion of a transfer.

Bus error on destination
BED is cleared at hardware reset or by writing a 1 to the DONE bit.
0
1

27
Reserved

No configuration error exists.
A configuration error has occurred.

No bus error occurred.
The DMA channel terminated with a bus error during the write portion of a transfer.

This field is reserved.
This read-only field is reserved and always has the value 0.

26
REQ

Request

25
BSY

Busy

24
DONE

0
1

0
1

DMA channel is inactive. Cleared when the DMA has finished the last transaction.
BSY is set the first time the channel is enabled after a transfer is initiated.

Transactions done
Set when all DMA controller transactions complete as determined by transfer count, or based on error
conditions. When BCR reaches zero, DONE is set when the final transfer completes successfully. DONE
can also be used to abort a transfer by resetting the status bits. When a transfer completes, software must
clear DONE before reprogramming the DMA.
0
1

23–0
BCR

No request is pending or the channel is currently active. Cleared when the channel is selected.
The DMA channel has a transfer remaining and the channel is not selected.

DMA transfer is not yet complete. Writing a 0 has no effect.
DMA transfer completed. Writing a 1 to this bit clears all DMA status bits and should be used in an
interrupt service routine to clear the DMA interrupt and error bits.

This field contains the number of bytes yet to be transferred for a given block.
Restriction: BCR must be written with a value equal to or less than 0F_FFFFh. After being written with a
value in this range, bits 23-20 of BCR read back as 1110b. A write to BCR of a value
Table continues on the next page...

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Chapter 23 DMA Controller Module

DMA_DSR_BCRn field descriptions (continued)
Field

Description
greater than 0F_FFFFh causes a configuration error when the channel starts to execute.
After being written with a value in this range, bits 23-20 of BCR read back as 1111b.

23.3.4 DMA Control Register (DMA_DCRn)
Address: 4000_8000h base + 10Ch offset + (16d × i), where i=0d to 3d
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

0
EINT

ERQ

CS

AA

EADREQ

0
Reserved

R

SINC

Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Bit

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

DINC

DSIZE
START

SSIZE

W

0
SMOD

D_REQ

R

DMOD

LINKCC

LCH1

LCH2

W

Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

DMA_DCRn field descriptions
Field
31
EINT

Description
Enable interrupt on completion of transfer
Determines whether an interrupt is generated by completing a transfer or by the occurrence of an error
condition.
0
1

30
ERQ

No interrupt is generated.
Interrupt signal is enabled.

Enable peripheral request
CAUTION: Be careful: a collision can occur between the START bit and D_REQ when the ERQ bit is 1.
0
1

Peripheral request is ignored.
Enables peripheral request to initiate transfer. A software-initiated request (setting the START bit) is
always enabled.
Table continues on the next page...

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DMA_DCRn field descriptions (continued)
Field

Description

29
CS

Cycle steal

28
AA

Auto-align

0
1

DMA continuously makes read/write transfers until the BCR decrements to 0.
Forces a single read/write transfer per request.

AA and SIZE bits determine whether the source or destination is auto-aligned; that is, transfers are
optimized based on the address and size.
0
1

Auto-align disabled
If SSIZE indicates a transfer no smaller than DSIZE, source accesses are auto-aligned; otherwise,
destination accesses are auto-aligned. Source alignment takes precedence over destination
alignment. If auto-alignment is enabled, the appropriate address register increments, regardless of
DINC or SINC.

27–25
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

24
Reserved

This field is reserved.
CAUTION: Must be written as zero; otherwise, undefined behavior results.

23
EADREQ

Enable asynchronous DMA requests
Enables the channel to support asynchronous DREQs while the MCU is in Stop mode.
0
1

22
SINC

Source increment
Controls whether the source address increments after each successful transfer.
0
1

21–20
SSIZE

Determines the data size of the source bus cycle for the DMA controller.
32-bit
8-bit
16-bit
Reserved (generates a configuration error (DSRn[CE]) if incorrectly specified at time of channel
activation)

Destination increment
Controls whether the destination address increments after each successful transfer.
0
1

18–17
DSIZE

No change to SAR after a successful transfer.
The SAR increments by 1, 2, 4 as determined by the transfer size.

Source size

00
01
10
11
19
DINC

Disabled
Enabled

No change to the DAR after a successful transfer.
The DAR increments by 1, 2, 4 depending upon the size of the transfer.

Destination size
Determines the data size of the destination bus cycle for the DMA controller.
00
01

32-bit
8-bit
Table continues on the next page...

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Chapter 23 DMA Controller Module

DMA_DCRn field descriptions (continued)
Field

Description
10
11

16-bit
Reserved (generates a configuration error (DSRn[CE]) if incorrectly specified at time of channel
activation)

16
START

Start transfer

15–12
SMOD

Source address modulo

0
1

DMA inactive
The DMA begins the transfer in accordance to the values in the TCDn. START is cleared
automatically after one module clock and always reads as logic 0.

Defines the size of the source data circular buffer used by the DMA Controller. If enabled (SMOD is nonzero), the buffer base address is located on a boundary of the buffer size. The value of this boundary is
based upon the initial source address (SAR). The base address should be aligned to a 0-modulo-(circular
buffer size) boundary. Misaligned buffers are not possible. The boundary is forced to the value determined
by the upper address bits in the field selection.
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111

11–8
DMOD

Buffer disabled
Circular buffer size is 16 bytes
Circular buffer size is 32 bytes
Circular buffer size is 64 bytes
Circular buffer size is 128 bytes
Circular buffer size is 256 bytes
Circular buffer size is 512 bytes
Circular buffer size is 1 KB
Circular buffer size is 2 KB
Circular buffer size is 4 KB
Circular buffer size is 8 KB
Circular buffer size is 16 KB
Circular buffer size is 32 KB
Circular buffer size is 64 KB
Circular buffer size is 128 KB
Circular buffer size is 256 KB

Destination address modulo
Defines the size of the destination data circular buffer used by the DMA Controller. If enabled (DMOD
value is non-zero), the buffer base address is located on a boundary of the buffer size. The value of this
boundary depends on the initial destination address (DAR). The base address should be aligned to a 0modulo-(circular buffer size) boundary. Misaligned buffers are not possible. The boundary is forced to the
value determined by the upper address bits in the field selection.
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001

Buffer disabled
Circular buffer size is 16 bytes
Circular buffer size is 32 bytes
Circular buffer size is 64 bytes
Circular buffer size is 128 bytes
Circular buffer size is 256 bytes
Circular buffer size is 512 bytes
Circular buffer size is 1 KB
Circular buffer size is 2 KB
Circular buffer size is 4 KB
Table continues on the next page...

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DMA_DCRn field descriptions (continued)
Field

Description
1010
1011
1100
1101
1110
1111

7
D_REQ

Disable request
DMA hardware automatically clears the corresponding DCRn[ERQ] bit when the byte count register
reaches zero.
0
1

6
Reserved
5–4
LINKCC

Circular buffer size is 8 KB
Circular buffer size is 16 KB
Circular buffer size is 32 KB
Circular buffer size is 64 KB
Circular buffer size is 128 KB
Circular buffer size is 256 KB

ERQ bit is not affected.
ERQ bit is cleared when the BCR is exhausted.

This field is reserved.
This read-only field is reserved and always has the value 0.
Link channel control
Allows DMA channels to have their transfers linked. The current DMA channel triggers a DMA request to
the linked channels (LCH1 or LCH2) depending on the condition described by the LINKCC bits.
If not in cycle steal mode (DCRn[CS]=0) and LINKCC equals 01 or 10, no link to LCH1 occurs.
If LINKCC equals 01, a link to LCH1 is created after each cycle-steal transfer performed by the current
DMA channel is completed. As the last cycle-steal is performed and the BCR reaches zero, then the link to
LCH1 is closed and a link to LCH2 is created.
00
01
10
11

3–2
LCH1

Link channel 1
Indicates the DMA channel assigned as link channel 1. The link channel number cannot be the same as
the currently executing channel, and generates a configuration error if this is attempted (DSRn[CE] is set).
00
01
10
11

1–0
LCH2

No channel-to-channel linking
Perform a link to channel LCH1 after each cycle-steal transfer followed by a link to LCH2 after the
BCR decrements to zero
Perform a link to channel LCH1 after each cycle-steal transfer
Perform a link to channel LCH1 after the BCR decrements to zero

DMA Channel 0
DMA Channel 1
DMA Channel 2
DMA Channel 3

Link channel 2
Indicates the DMA channel assigned as link channel 2. The link channel number cannot be the same as
the currently executing channel, and generates a configuration error if this is attempted (DSRn[CE] is set).
00
01
10
11

DMA Channel 0
DMA Channel 1
DMA Channel 2
DMA Channel 3

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Chapter 23 DMA Controller Module

23.4 Functional Description
In the following discussion, the term DMA request implies that DCRn[START] is set, or
DCRn[ERQ] is set and then followed by assertion of the properly selected DMA
peripheral request. The START bit is cleared when the channel is activated.
Before initiating a dual-address access, the DMA module verifies that DCRn[SSIZE] and
DCRn[DSIZE] are consistent with the source and destination addresses. If they are not
consistent, the configuration error bit, DSRn[CE], is set. If misalignment is detected, no
transfer occurs, DSRn[CE] is set, and, depending on the DCR configuration, an interrupt
event may be issued. If the auto-align bit, DCRn[AA], is set, error checking is performed
on the appropriate registers.
A read/write transfer sequence reads data from the source address and writes it to the
destination address. The number of bytes transferred is the largest of the sizes specified
by DCRn[SSIZE] and DCRn[DSIZE] in the DMA Control Registers (DCRn).
Source and destination address registers (SARn and DARn) can be programmed in the
DCRn to increment at the completion of a successful transfer.

23.4.1 Transfer Requests (Cycle-Steal and Continuous Modes)
The DMA channel supports software-initiated or peripheral-initiated requests. A request
is issued by setting DCRn[START] or when the selected peripheral request asserts and
DCRn[ERQ] is set. Setting DCRn[ERQ] enables recognition of the peripheral DMA
requests. Selecting between cycle-steal and continuous modes minimizes bus usage for
either type of request.
• Cycle-steal mode (DCRn[CS] = 1)—Only one complete transfer from source to
destination occurs for each request. If DCRn[ERQ] is set, the request is peripheral
initiated. A software-initiated request is enabled by setting DCRn[START].
• Continuous mode (DCRn[CS] = 0)—After a software-initiated or peripheral request,
the DMA continuously transfers data until BCRn reaches zero. The DMA performs
the specified number of transfers, then retires the channel.
In either mode, the crossbar switch performs independent arbitration on each slave port
after each transaction.

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23.4.2 Channel Initialization and Startup
Before a data transfer starts, the channel's transfer control descriptor must be initialized
with information describing configuration, request-generation method, and pointers to the
data to be moved.

23.4.2.1 Channel Prioritization
The four DMA channels are prioritized based on number, with channel 0 having highest
priority and channel 3 having the lowest, that is, channel 0 > channel 1 > channel 2 >
channel 3.
Simultaneous peripheral requests activate the channels based on this priority order. Once
activated, a channel runs to completion as defined by DCRn[CS] and BCRn.

23.4.2.2 Programming the DMA Controller Module
CAUTION
During a channel's execution, writes to programming model
registers can corrupt the data transfer. The DMA module itself
does not have a mechanism to prevent writes to registers during
a channel's execution.
General guidelines for programming the DMA are:
• TCDn is initialized.
• SARn is loaded with the source (read) address. If the transfer is from a
peripheral device to memory or to another peripheral, the source address is the
location of the peripheral data register. If the transfer is from memory to a
peripheral device or to memory, the source address is the starting address of the
data block. This can be any appropriately aligned address.
• DARn is initialized with the destination (write) address. If the transfer is from a
peripheral device to memory, or from memory to memory, DARn is loaded with
the starting address of the data block to be written. If the transfer is from
memory to a peripheral device, or from a peripheral device to a peripheral
device, DARn is loaded with the address of the peripheral data register. This
address can be any appropriately aligned address.

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Chapter 23 DMA Controller Module

• SARn and DARn change after each data transfer depending on DCRn[SSIZE,
DSIZE, SINC, DINC, SMOD, DMOD] and the starting addresses. Increment
values can be 1, 2, or 4 for 8-bit, 16-bit, or 32-bit transfers, respectively. If the
address register is programmed to remain unchanged, the register is not
incremented after the data transfer.
• BCRn[BCR] must be loaded with the total number of bytes to be transferred. It
is decremented by 1, 2, or 4 at the end of each transfer, depending on the transfer
size. DSRn[DONE] must be cleared for channel startup.
• After the channel has been initialized, it may be started by setting DCRn[START] or
a properly selected peripheral DMA request, depending on the status of
DCRn[ERQ]. For a software-initiated transfer, the channel can be started by setting
DCRn[START] as part of a single 32-bit write to the last 32 bits of the TCDn; that is,
it is not required to write the DCRn with START cleared and then perform a second
write to explicitly set START.
• Programming the channel for a software-initiated request causes the channel to
request the system bus and start transferring data immediately. If the channel is
programmed for peripheral-initiated request, a properly selected peripheral DMA
request must be asserted before the channel begins the system bus transfers.
• The hardware can automatically clear DCRn[ERQ], disabling the peripheral request,
when BCRn reaches zero by setting DCRn[D_REQ].
• Changes to DCRn are effective immediately while the channel is active. To avoid
problems with changing a DMA channel setup, write a one to DSRn[DONE] to stop
the DMA channel.

23.4.3 Dual-Address Data Transfer Mode
Each channel supports dual-address transfers. Dual-address transfers consist of a source
data read and a destination data write. The DMA controller module begins a dual-address
transfer sequence after a DMA request. If no error condition exists, DSRn[REQ] is set.
• Dual-address read—The DMA controller drives the SARn value onto the system
address bus. If DCRn[SINC] is set, the SARn increments by the appropriate number
of bytes upon a successful read cycle. When the appropriate number of read cycles
complete (multiple reads if the destination size is larger than the source), the DMA
initiates the write portion of the transfer.
If a termination error occurs, DSRn[BES, DONE] are set and DMA transactions stop.
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• Dual-address write—The DMA controller drives the DARn value onto the system
address bus. When the appropriate number of write cycles complete (multiple writes
if the source size is larger than the destination), DARn increments by the appropriate
number of bytes if DCRn[DINC] is set. BCRn decrements by the appropriate number
of bytes. DSRn[DONE] is set when BCRn reaches zero. If the BCRn is greater than
zero, another read/write transfer is initiated if continuous mode is enabled
(DCRn[CS] = 0).
If a termination error occurs, DSRn[BED, DONE] are set and DMA transactions
stop.

23.4.4 Advanced Data Transfer Controls: Auto-Alignment
Typically, auto-alignment for DMA transfers applies for transfers of large blocks of data.
As a result, it does not apply for peripheral-initiated cycle-steal transfers.
Auto-alignment allows block transfers to occur at the optimal size based on the address,
byte count, and programmed size. To use this feature, DCRn[AA] must be set. The
source is auto-aligned if DCRn[SSIZE] indicates a transfer size larger than
DCRn[DSIZE]. Source alignment takes precedence over the destination when the source
and destination sizes are equal. Otherwise, the destination is auto-aligned. The address
register chosen for alignment increments regardless of the increment value. Configuration
error checking is performed on registers not chosen for alignment.
If BCRn is greater than 16, the address determines transfer size. Transfers of 8 bits, 16
bits, or 32 bits are transferred until the address is aligned to the programmed size
boundary, at which time accesses begin using the programmed size. If BCRn is less than
16 at the start of a transfer, the number of bytes remaining dictates transfer size.
Consider this example:
• AA equals 1.
• SARn equals 0x2000_0001.
• BCRn equals 0x00_00F0.
• SSIZE equals 00 (32 bits).
• DSIZE equals 01 (8 bits).
Because SSIZE > DSIZE, the source is auto-aligned. Error checking is performed on
destination registers. The access sequence is as follows:
1. Read 1 byte from 0x2000_0001, increment SARn, write 1 byte (using DARn).
2. Read 2 bytes from 0x2000_0002, increment SARn, write 2 bytes.

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Chapter 23 DMA Controller Module

3. Read 4 bytes from 0x2000_0004, increment SARn, write 4 bytes.
4. Repeat 4-byte operations until SARn equals 0x2000_00F0.
5. Read byte from 0x2000_00F0, increment SARn, write byte.
If DSIZE is another size, data writes are optimized to write the largest size allowed based
on the address, but not exceeding the configured size.

23.4.5 Termination
An unsuccessful transfer can terminate for one of the following reasons:
• Error conditions—When the DMA encounters a read or write cycle that terminates
with an error condition, DSRn[BES] is set for a read and DSRn[BED] is set for a
write before the transfer is halted. If the error occurred in a write cycle, data in the
internal holding registers is lost.
• Interrupts—If DCRn[EINT] is set, the DMA drives the appropriate interrupt request
signal. The processor can read DSRn to determine whether the transfer terminated
successfully or with an error. DSRn[DONE] is then written with a one to clear the
interrupt, the DONE, and error status bits.

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Chapter 24
Multipurpose Clock Generator (MCG)
24.1 Introduction
NOTE
For the chip-specific implementation details of this module's
instances see the chip configuration information.
The multipurpose clock generator (MCG) module provides several clock source choices
for the MCU. The module contains a frequency-locked loop (FLL) and a phase-locked
loop (PLL). The FLL is controllable by either an internal or an external reference clock.
The PLL is controllable by the external reference clock. The module can select either of
the FLL or PLL output clocks, or either of the internal or external reference clocks as a
source for the MCU system clock. The MCG operates in conjuction with a crystal
oscillator, which allows an external crystal, ceramic resonator, or another external clock
source to produce the external reference clock.

24.1.1 Features
Key features of the MCG module are:
• Frequency-locked loop (FLL):
• Digitally-controlled oscillator (DCO)
• DCO frequency range is programmable for up to four different frequency ranges.
• Option to program and maximize DCO output frequency for a low frequency
external reference clock source.
• Option to prevent FLL from resetting its current locked frequency when
switching clock modes if FLL reference frequency is not changed.

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• Internal or external reference clock can be used as the FLL source.
• Can be used as a clock source for other on-chip peripherals.
• Phase-locked loop (PLL):
• Voltage-controlled oscillator (VCO)
• External reference clock is used as the PLL source.
• Modulo VCO frequency divider
• Phase/Frequency detector
• Integrated loop filter
• Can be used as a clock source for other on-chip peripherals.
• Internal reference clock generator:
• Slow clock with nine trim bits for accuracy
• Fast clock with four trim bits
• Can be used as source clock for the FLL. In FEI mode, only the slow Internal
Reference Clock (IRC) can be used as the FLL source.
• Either the slow or the fast clock can be selected as the clock source for the MCU.
• Can be used as a clock source for other on-chip peripherals.
• Control signals for the MCG external reference low power oscillator clock generators
are provided:
• HGO0, RANGE0, EREFS0
• External clock from the Crystal Oscillator :
• Can be used as a source for the FLL and/or the PLL.
• Can be selected as the clock source for the MCU.
• External clock monitor with reset and interrupt request capability to check for
external clock failure when running in FBE, PEE, BLPE, or FEE modes
• Lock detector with interrupt request capability for use with the PLL
• Internal Reference Clocks Auto Trim Machine (ATM) capability using an external
clock as a reference
• Reference dividers for both the FLL and the PLL are provided

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Chapter 24 Multipurpose Clock Generator (MCG)

• Reference dividers for the Fast Internal Reference Clock are provided
• MCG PLL Clock (MCGPLLCLK) is provided as a clock source for other on-chip
peripherals
• MCG FLL Clock (MCGFLLCLK) is provided as a clock source for other on-chip
peripherals
• MCG Fixed Frequency Clock (MCGFFCLK) is provided as a clock source for other
on-chip peripherals
• MCG Internal Reference Clock (MCGIRCLK) is provided as a clock source for other
on-chip peripherals

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Introduction

Crystal Oscillator
External Reference Clock

CLKS

ATMS

OSCINIT0

PLLCLKEN0

EREFS0

IREFS

HGO0

PLLS

RANGE0

MCG Crystal Oscillator
Enable Detect

STOP
IREFSTEN

Auto Trim Machine

IRCLKEN
SCTRIM

Internal
Reference

SCFTRIM

Clock
Generator

FCTRIM

MCGIRCLK

IRCS

CLKS

Slow Clock
Fast Clock

/

2n

IRCSCLK

n=0-7

MCGOUTCLK

MCGFLLCLK

CME0 LOCRE0
DRS

External
Clock
Monitor

DMX32

Filter

DCO

FLTPRSRV

LOCS0

PLLS

DCOOUT
FLL

FRDIV
/

IREFS

Clock
Valid

LP

2n

n=0-7

/ 25

Sync

MCGFFCLK

PRDIV0
LOLIE0
/(1,2,3,4,5....,25)

PLLCLKEN0
IREFST

PLLST
Peripheral BUSCLK

CLKST
IRCST
ATMST

Phase
Detector

Charge
Pump

VDIV0

Internal
Filter

/(24,25,26,...,55)

VCO

Lock
Detector

LOLS0 LOCK0
MCGPLLCLK

VCOOUT
PLL
Multipurpose Clock Generator (MCG)

Figure 24-1. Multipurpose Clock Generator (MCG) block diagram

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Chapter 24 Multipurpose Clock Generator (MCG)

24.1.2 Modes of Operation
The MCG has the following modes of operation: FEI, FEE, FBI, FBE, PBE, PEE, BLPI,
BLPE, and Stop. For details, see MCG modes of operation.

24.2 External Signal Description
There are no MCG signals that connect off chip.

24.3 Memory Map/Register Definition
This section includes the memory map and register definition.
The MCG registers can only be written when in supervisor mode. Write accesses when in
user mode will result in a bus error. Read accesses may be performed in both supervisor
and user mode.
MCG memory map
Absolute
address
(hex)

Register name

Width
Access
(in bits)

Reset value

Section/
page

04h

24.3.1/372

4006_4000

MCG Control 1 Register (MCG_C1)

8

R/W

4006_4001

MCG Control 2 Register (MCG_C2)

8

R/W

80h

24.3.2/373

4006_4002

MCG Control 3 Register (MCG_C3)

8

R/W

Undefined

24.3.3/374

4006_4003

MCG Control 4 Register (MCG_C4)

8

R/W

Undefined

24.3.4/374

4006_4004

MCG Control 5 Register (MCG_C5)

8

R/W

00h

24.3.5/376

4006_4005

MCG Control 6 Register (MCG_C6)

8

R/W

00h

24.3.6/377

4006_4006

MCG Status Register (MCG_S)

8

R

10h

24.3.7/378

4006_4008

MCG Status and Control Register (MCG_SC)

8

R/W

02h

24.3.8/380

4006_400A

MCG Auto Trim Compare Value High Register
(MCG_ATCVH)

8

R/W

00h

24.3.9/381

4006_400B

MCG Auto Trim Compare Value Low Register
(MCG_ATCVL)

8

R/W

00h

24.3.10/381

4006_400C

MCG Control 7 Register (MCG_C7)

8

R/W

00h

24.3.11/382

4006_400D

MCG Control 8 Register (MCG_C8)

8

R/W

80h

24.3.12/382

4006_400E

MCG Control 9 Register (MCG_C9)

8

R/W

00h

24.3.13/383

4006_400F

MCG Control 10 Register (MCG_C10)

8

R/W

00h

24.3.14/383

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24.3.1 MCG Control 1 Register (MCG_C1)
Address: 4006_4000h base + 0h offset = 4006_4000h
Bit

Read
Write
Reset

7

6

5

CLKS
0

4

3

FRDIV
0

0

0

0

2

1

0

IREFS

IRCLKEN

IREFSTEN

1

0

0

MCG_C1 field descriptions
Field
7–6
CLKS

Description
Clock Source Select
Selects the clock source for MCGOUTCLK .
00
01
10
11

5–3
FRDIV

FLL External Reference Divider
Selects the amount to divide down the external reference clock for the FLL. The resulting frequency must
be in the range 31.25 kHz to 39.0625 kHz (This is required when FLL/DCO is the clock source for
MCGOUTCLK . In FBE mode, it is not required to meet this range, but it is recommended in the cases
when trying to enter a FLL mode from FBE).
000
001
010
011
100
101
110
111

2
IREFS

Selects the reference clock source for the FLL.
External reference clock is selected.
The slow internal reference clock is selected.

Internal Reference Clock Enable
Enables the internal reference clock for use as MCGIRCLK.
0
1

0
IREFSTEN

If RANGE 0 = 0 , Divide Factor is 1; for all other RANGE 0 values, Divide Factor is 32.
If RANGE 0 = 0 , Divide Factor is 2; for all other RANGE 0 values, Divide Factor is 64.
If RANGE 0 = 0 , Divide Factor is 4; for all other RANGE 0 values, Divide Factor is 128.
If RANGE 0 = 0 , Divide Factor is 8; for all other RANGE 0 values, Divide Factor is 256.
If RANGE 0 = 0 , Divide Factor is 16; for all other RANGE 0 values, Divide Factor is 512.
If RANGE 0 = 0 , Divide Factor is 32; for all other RANGE 0 values, Divide Factor is 1024.
If RANGE 0 = 0 , Divide Factor is 64; for all other RANGE 0 values, Divide Factor is 1280 .
If RANGE 0 = 0 , Divide Factor is 128; for all other RANGE 0 values, Divide Factor is 1536 .

Internal Reference Select

0
1
1
IRCLKEN

Encoding 0 — Output of FLL or PLL is selected (depends on PLLS control bit).
Encoding 1 — Internal reference clock is selected.
Encoding 2 — External reference clock is selected.
Encoding 3 — Reserved.

MCGIRCLK inactive.
MCGIRCLK active.

Internal Reference Stop Enable
Controls whether or not the internal reference clock remains enabled when the MCG enters Stop mode.
0
1

Internal reference clock is disabled in Stop mode.
Internal reference clock is enabled in Stop mode if IRCLKEN is set or if MCG is in FEI, FBI, or BLPI
modes before entering Stop mode.

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Chapter 24 Multipurpose Clock Generator (MCG)

24.3.2 MCG Control 2 Register (MCG_C2)
Address: 4006_4000h base + 1h offset = 4006_4001h
Bit

Read
Write
Reset

7

6

LOCRE0

0

1

0

5

4

RANGE0
0

3

2

1

0

HGO0

EREFS0

LP

IRCS

0

0

0

0

0

MCG_C2 field descriptions
Field
7
LOCRE0

Description
Loss of Clock Reset Enable
Determines whether an interrupt or a reset request is made following a loss of OSC0 external reference
clock. The LOCRE0 only has an affect when CME0 is set.
0
1

Interrupt request is generated on a loss of OSC0 external reference clock.
Generate a reset request on a loss of OSC0 external reference clock.

6
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

5–4
RANGE0

Frequency Range Select
Selects the frequency range for the crystal oscillator or external clock source. See the Oscillator (OSC)
chapter for more details and the device data sheet for the frequency ranges used.
00
01
1X

3
HGO0

High Gain Oscillator Select
Controls the crystal oscillator mode of operation. See the Oscillator (OSC) chapter for more details.
0
1

2
EREFS0

Selects the source for the external reference clock. See the Oscillator (OSC) chapter for more details.
External reference clock requested.
Oscillator requested.

Low Power Select
Controls whether the FLL or PLL is disabled in BLPI and BLPE modes. In FBE or PBE modes, setting this
bit to 1 will transition the MCG into BLPE mode; in FBI mode, setting this bit to 1 will transition the MCG
into BLPI mode. In any other MCG mode, LP bit has no affect.
0
1

0
IRCS

Configure crystal oscillator for low-power operation.
Configure crystal oscillator for high-gain operation.

External Reference Select

0
1
1
LP

Encoding 0 — Low frequency range selected for the crystal oscillator .
Encoding 1 — High frequency range selected for the crystal oscillator .
Encoding 2 — Very high frequency range selected for the crystal oscillator .

FLL or PLL is not disabled in bypass modes.
FLL or PLL is disabled in bypass modes (lower power)

Internal Reference Clock Select
Selects between the fast or slow internal reference clock source.
Table continues on the next page...

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MCG_C2 field descriptions (continued)
Field

Description
0
1

Slow internal reference clock selected.
Fast internal reference clock selected.

24.3.3 MCG Control 3 Register (MCG_C3)
Address: 4006_4000h base + 2h offset = 4006_4002h
Bit

Read
Write
Reset

7

6

5

4

3

2

1

0

x*

x*

x*

x*

SCTRIM
x*

x*

x*

x*

* Notes:
• x = Undefined at reset.

MCG_C3 field descriptions
Field
7–0
SCTRIM

Description
Slow Internal Reference Clock Trim Setting
SCTRIM 1 controls the slow internal reference clock frequency by controlling the slow internal reference
clock period. The SCTRIM bits are binary weighted, that is, bit 1 adjusts twice as much as bit 0. Increasing
the binary value increases the period, and decreasing the value decreases the period.
An additional fine trim bit is available in C4 register as the SCFTRIM bit. Upon reset, this value is loaded
with a factory trim value.
If an SCTRIM value stored in nonvolatile memory is to be used, it is your responsibility to copy that value
from the nonvolatile memory location to this register.

1. A value for SCTRIM is loaded during reset from a factory programmed location .

24.3.4 MCG Control 4 Register (MCG_C4)
NOTE
Reset values for DRST and DMX32 bits are 0.
Address: 4006_4000h base + 3h offset = 4006_4003h
Bit

Read
Write
Reset

7

6

DMX32
0

5

4

3

DRST_DRS
0

2

1

FCTRIM
0

x*

x*

0

SCFTRIM
x*

x*

x*

* Notes:
• x = Undefined at reset.
• A value for FCTRIM is loaded during reset from a factory programmed location . x = Undefined at reset.

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MCG_C4 field descriptions
Field
7
DMX32

Description
DCO Maximum Frequency with 32.768 kHz Reference
The DMX32 bit controls whether the DCO frequency range is narrowed to its maximum frequency with a
32.768 kHz reference.
The following table identifies settings for the DCO frequency range.
NOTE: The system clocks derived from this source should not exceed their specified maximums.
DRST_DRS

DMX32

Reference Range

FLL Factor

DCO Range

00

0

31.25–39.0625 kHz

640

20–25 MHz

1

32.768 kHz

732

24 MHz

0

31.25–39.0625 kHz

1280

40–50 MHz

1

32.768 kHz

1464

48 MHz

0

31.25–39.0625 kHz

1920

60–75 MHz

1

32.768 kHz

2197

72 MHz

0

31.25–39.0625 kHz

2560

80–100 MHz

1

32.768 kHz

2929

96 MHz

01
10
11

0
1
6–5
DRST_DRS

DCO Range Select
The DRS bits select the frequency range for the FLL output, DCOOUT. When the LP bit is set, writes to
the DRS bits are ignored. The DRST read field indicates the current frequency range for DCOOUT. The
DRST field does not update immediately after a write to the DRS field due to internal synchronization
between clock domains. See the DCO Frequency Range table for more details.
00
01
10
11

4–1
FCTRIM

DCO has a default range of 25%.
DCO is fine-tuned for maximum frequency with 32.768 kHz reference.

Encoding 0 — Low range (reset default).
Encoding 1 — Mid range.
Encoding 2 — Mid-high range.
Encoding 3 — High range.

Fast Internal Reference Clock Trim Setting
FCTRIM 1 controls the fast internal reference clock frequency by controlling the fast internal reference
clock period. The FCTRIM bits are binary weighted, that is, bit 1 adjusts twice as much as bit 0. Increasing
the binary value increases the period, and decreasing the value decreases the period.
If an FCTRIM[3:0] value stored in nonvolatile memory is to be used, it is your responsibility to copy that
value from the nonvolatile memory location to this register.

0
SCFTRIM

Slow Internal Reference Clock Fine Trim
SCFTRIM 2 controls the smallest adjustment of the slow internal reference clock frequency. Setting
SCFTRIM increases the period and clearing SCFTRIM decreases the period by the smallest amount
possible.
If an SCFTRIM value stored in nonvolatile memory is to be used, it is your responsibility to copy that value
from the nonvolatile memory location to this bit.

1. A value for FCTRIM is loaded during reset from a factory programmed location .
2. A value for SCFTRIM is loaded during reset from a factory programmed location .

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24.3.5 MCG Control 5 Register (MCG_C5)
Address: 4006_4000h base + 4h offset = 4006_4004h
Bit

7

Read
Write
Reset

0

6

5

4

3

2

PLLCLKEN0 PLLSTEN0

0

0

1

0

0

0

PRDIV0

0

0

0

0

MCG_C5 field descriptions
Field
7
Reserved
6
PLLCLKEN0

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
PLL Clock Enable
Enables the PLL independent of PLLS and enables the PLL clock for use as MCGPLLCLK. (PRDIV 0
needs to be programmed to the correct divider to generate a PLL reference clock in the range of 2 - 4 MHz
range prior to setting the PLLCLKEN 0 bit). Setting PLLCLKEN 0 will enable the external oscillator if not
already enabled. Whenever the PLL is being enabled by means of the PLLCLKEN 0 bit, and the external
oscillator is being used as the reference clock, the OSCINIT 0 bit should be checked to make sure it is set.
0
1

5
PLLSTEN0

MCGPLLCLK is active.

PLL Stop Enable
Enables the PLL Clock during Normal Stop. In Low Power Stop mode, the PLL clock gets disabled even if
PLLSTEN 0 =1. All other power modes, PLLSTEN 0 bit has no affect and does not enable the PLL Clock
to run if it is written to 1.
0
1

4–0
PRDIV0

MCGPLLCLK is inactive.

MCGPLLCLK is disabled in any of the Stop modes.
MCGPLLCLK is enabled if system is in Normal Stop mode.

PLL External Reference Divider
Selects the amount to divide down the external reference clock for the PLL. The resulting frequency must
be in the range of 2 MHz to 4 MHz. After the PLL is enabled (by setting either PLLCLKEN 0 or PLLS), the
PRDIV 0 value must not be changed when LOCK0 is zero.

Table 24-7. PLL External Reference Divide Factor
PRDIV
0

Divide
Factor

PRDIV
0

Divide
Factor

PRDIV
0

Divide
Factor

PRDIV
0

Divide
Factor

00000

1

01000

9

10000

17

11000

25

00001

2

01001

10

10001

18

11001

Reserve
d

00010

3

01010

11

10010

19

11010

Reserve
d

00011

4

01011

12

10011

20

11011

Reserve
d

Table continues on the next page...

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Chapter 24 Multipurpose Clock Generator (MCG)

MCG_C5 field descriptions (continued)
Field

Description

Table 24-7. PLL External Reference Divide Factor (continued)
00100

5

01100

13

10100

21

11100

Reserve
d

00101

6

01101

14

10101

22

11101

Reserve
d

00110

7

01110

15

10110

23

11110

Reserve
d

00111

8

01111

16

10111

24

11111

Reserve
d

24.3.6 MCG Control 6 Register (MCG_C6)
Address: 4006_4000h base + 5h offset = 4006_4005h
Bit

Read
Write
Reset

7

6

5

LOLIE0

PLLS

CME0

0

0

0

4

3

2

1

0

0

0

VDIV0
0

0

0

MCG_C6 field descriptions
Field
7
LOLIE0

Description
Loss of Lock Interrrupt Enable
Determines if an interrupt request is made following a loss of lock indication. This bit only has an effect
when LOLS 0 is set.
0
1

6
PLLS

PLL Select
Controls whether the PLL or FLL output is selected as the MCG source when CLKS[1:0]=00. If the PLLS
bit is cleared and PLLCLKEN 0 is not set, the PLL is disabled in all modes. If the PLLS is set, the FLL is
disabled in all modes.
0
1

5
CME0

No interrupt request is generated on loss of lock.
Generate an interrupt request on loss of lock.

FLL is selected.
PLL is selected (PRDIV 0 need to be programmed to the correct divider to generate a PLL reference
clock in the range of 2–4 MHz prior to setting the PLLS bit).

Clock Monitor Enable
Enables the loss of clock monitoring circuit for the OSC0 external reference mux select. The LOCRE0 bit
will determine if a interrupt or a reset request is generated following a loss of OSC0 indication. The CME0
bit should only be set to a logic 1 when the MCG is in an operational mode that uses the external clock
(FEE, FBE, PEE, PBE, or BLPE) . Whenever the CME0 bit is set to a logic 1, the value of the RANGE0
bits in the C2 register should not be changed. CME0 bit should be set to a logic 0 before the MCG enters
Table continues on the next page...

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MCG_C6 field descriptions (continued)
Field

Description
any Stop mode. Otherwise, a reset request may occur while in Stop mode. CME0 should also be set to a
logic 0 before entering VLPR or VLPW power modes if the MCG is in BLPE mode.
0
1

4–0
VDIV0

External clock monitor is disabled for OSC0.
External clock monitor is enabled for OSC0.

VCO 0 Divider
Selects the amount to divide the VCO output of the PLL. The VDIV 0 bits establish the multiplication factor
(M) applied to the reference clock frequency. After the PLL is enabled (by setting either PLLCLKEN 0 or
PLLS), the VDIV 0 value must not be changed when LOCK 0 is zero.

Table 24-9. PLL VCO Divide Factor
VDIV 0

Multiply
Factor

VDIV 0

Multiply
Factor

VDIV 0

Multiply
Factor

VDIV 0

Multiply
Factor

00000

24

01000

32

10000

40

11000

48

00001

25

01001

33

10001

41

11001

49

00010

26

01010

34

10010

42

11010

50

00011

27

01011

35

10011

43

11011

51

00100

28

01100

36

10100

44

11100

52

00101

29

01101

37

10101

45

11101

53

00110

30

01110

38

10110

46

11110

54

00111

31

01111

39

10111

47

11111

55

24.3.7 MCG Status Register (MCG_S)
Address: 4006_4000h base + 6h offset = 4006_4006h
Bit

Read

7

6

5

4

3

LOLS

LOCK0

PLLST

IREFST

0

0

0

1

2

CLKST

1

0

OSCINIT0

IRCST

0

0

Write
Reset

0

0

MCG_S field descriptions
Field
7
LOLS

Description
Loss of Lock Status
This bit is a sticky bit indicating the lock status for the PLL. LOLS is set if after acquiring lock, the PLL
output frequency has fallen outside the lock exit frequency tolerance, D unl . LOLIE determines whether an
interrupt request is made when LOLS is set. LOLRE determines whether a reset request is made when
LOLS is set. This bit is cleared by reset or by writing a logic 1 to it when set. Writing a logic 0 to this bit has
no effect.
Table continues on the next page...

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Chapter 24 Multipurpose Clock Generator (MCG)

MCG_S field descriptions (continued)
Field

Description
0
1

6
LOCK0

Lock Status
This bit indicates whether the PLL has acquired lock. Lock detection is only enabled when the PLL is
enabled (either through clock mode selection or PLLCLKEN0=1 setting). While the PLL clock is locking to
the desired frequency, the MCG PLL clock (MCGPLLCLK) will be gated off until the LOCK bit gets
asserted. If the lock status bit is set, changing the value of the PRDIV0 [4:0] bits in the C5 register or the
VDIV0[4:0] bits in the C6 register causes the lock status bit to clear and stay cleared until the PLL has
reacquired lock. Loss of PLL reference clock will also cause the LOCK0 bit to clear until the PLL has
reacquired lock. Entry into LLS, VLPS, or regular Stop with PLLSTEN=0 also causes the lock status bit to
clear and stay cleared until the Stop mode is exited and the PLL has reacquired lock. Any time the PLL is
enabled and the LOCK0 bit is cleared, the MCGPLLCLK will be gated off until the LOCK0 bit is asserted
again.
0
1

5
PLLST

This bit indicates the clock source selected by PLLS . The PLLST bit does not update immediately after a
write to the PLLS bit due to internal synchronization between clock domains.

This bit indicates the current source for the FLL reference clock. The IREFST bit does not update
immediately after a write to the IREFS bit due to internal synchronization between clock domains.

0
IRCST

Source of FLL reference clock is the external reference clock.
Source of FLL reference clock is the internal reference clock.

Clock Mode Status
These bits indicate the current clock mode. The CLKST bits do not update immediately after a write to the
CLKS bits due to internal synchronization between clock domains.
00
01
10
11

1
OSCINIT0

Source of PLLS clock is FLL clock.
Source of PLLS clock is PLL output clock.

Internal Reference Status

0
1
3–2
CLKST

PLL is currently unlocked.
PLL is currently locked.

PLL Select Status

0
1
4
IREFST

PLL has not lost lock since LOLS 0 was last cleared.
PLL has lost lock since LOLS 0 was last cleared.

Encoding 0 — Output of the FLL is selected (reset default).
Encoding 1 — Internal reference clock is selected.
Encoding 2 — External reference clock is selected.
Encoding 3 — Output of the PLL is selected.

OSC Initialization
This bit, which resets to 0, is set to 1 after the initialization cycles of the crystal oscillator clock have
completed. After being set, the bit is cleared to 0 if the OSC is subsequently disabled. See the OSC
module's detailed description for more information.
Internal Reference Clock Status
The IRCST bit indicates the current source for the internal reference clock select clock (IRCSCLK). The
IRCST bit does not update immediately after a write to the IRCS bit due to internal synchronization
between clock domains. The IRCST bit will only be updated if the internal reference clock is enabled,
either by the MCG being in a mode that uses the IRC or by setting the C1[IRCLKEN] bit .
Table continues on the next page...

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MCG_S field descriptions (continued)
Field

Description
0
1

Source of internal reference clock is the slow clock (32 kHz IRC).
Source of internal reference clock is the fast clock (4 MHz IRC).

24.3.8 MCG Status and Control Register (MCG_SC)
Address: 4006_4000h base + 8h offset = 4006_4008h
Bit

Read
Write
Reset

7

6

ATME

ATMS

0

0

5

ATMF

4

3

FLTPRSRV

0

0

2

1

LOCS0

FCRDIV
0

0

0

1

0

MCG_SC field descriptions
Field
7
ATME

Description
Automatic Trim Machine Enable
Enables the Auto Trim Machine to start automatically trimming the selected Internal Reference Clock.
NOTE: ATME deasserts after the Auto Trim Machine has completed trimming all trim bits of the IRCS
clock selected by the ATMS bit.
Writing to C1, C3, C4, and SC registers or entering Stop mode aborts the auto trim operation and clears
this bit.
0
1

6
ATMS

Automatic Trim Machine Select
Selects the IRCS clock for Auto Trim Test.
0
1

5
ATMF

32 kHz Internal Reference Clock selected.
4 MHz Internal Reference Clock selected.

Automatic Trim Machine Fail Flag
Fail flag for the Automatic Trim Machine (ATM). This bit asserts when the Automatic Trim Machine is
enabled, ATME=1, and a write to the C1, C3, C4, and SC registers is detected or the MCG enters into any
Stop mode. A write to ATMF clears the flag.
0
1

4
FLTPRSRV

Auto Trim Machine disabled.
Auto Trim Machine enabled.

Automatic Trim Machine completed normally.
Automatic Trim Machine failed.

FLL Filter Preserve Enable
This bit will prevent the FLL filter values from resetting allowing the FLL output frequency to remain the
same during clock mode changes where the FLL/DCO output is still valid. (Note: This requires that the
FLL reference frequency to remain the same as what it was prior to the new clock mode switch. Otherwise
FLL filter and frequency values will change.)
0
1

FLL filter and FLL frequency will reset on changes to currect clock mode.
Fll filter and FLL frequency retain their previous values during new clock mode change.
Table continues on the next page...

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Chapter 24 Multipurpose Clock Generator (MCG)

MCG_SC field descriptions (continued)
Field
3–1
FCRDIV

Description
Fast Clock Internal Reference Divider
Selects the amount to divide down the fast internal reference clock. The resulting frequency will be in the
range 31.25 kHz to 4 MHz (Note: Changing the divider when the Fast IRC is enabled is not supported).
000
001
010
011
100
101
110
111

0
LOCS0

Divide Factor is 1
Divide Factor is 2.
Divide Factor is 4.
Divide Factor is 8.
Divide Factor is 16
Divide Factor is 32
Divide Factor is 64
Divide Factor is 128.

OSC0 Loss of Clock Status
The LOCS0 indicates when a loss of OSC0 reference clock has occurred. The LOCS0 bit only has an
effect when CME0 is set. This bit is cleared by writing a logic 1 to it when set.
0
1

Loss of OSC0 has not occurred.
Loss of OSC0 has occurred.

24.3.9 MCG Auto Trim Compare Value High Register (MCG_ATCVH)
Address: 4006_4000h base + Ah offset = 4006_400Ah
Bit

Read
Write
Reset

7

6

5

4

3

2

1

0

0

0

0

0

ATCVH
0

0

0

0

MCG_ATCVH field descriptions
Field
7–0
ATCVH

Description
ATM Compare Value High
Values are used by Auto Trim Machine to compare and adjust Internal Reference trim values during ATM
SAR conversion.

24.3.10 MCG Auto Trim Compare Value Low Register (MCG_ATCVL)
Address: 4006_4000h base + Bh offset = 4006_400Bh
Bit

Read
Write
Reset

7

6

5

4

3

2

1

0

0

0

0

0

ATCVL
0

0

0

0

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MCG_ATCVL field descriptions
Field
7–0
ATCVL

Description
ATM Compare Value Low
Values are used by Auto Trim Machine to compare and adjust Internal Reference trim values during ATM
SAR conversion.

24.3.11 MCG Control 7 Register (MCG_C7)
Address: 4006_4000h base + Ch offset = 4006_400Ch
Bit

Read
Write
Reset

7

6

5

4

0
0

3

2

1

0
0

0

0

0

0

0

0

0

0

2

1

0

MCG_C7 field descriptions
Field

Description

7–6
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

5–1
Reserved

Reserved

0
Reserved

Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

This field is reserved.
This read-only field is reserved and always has the value 0.

24.3.12 MCG Control 8 Register (MCG_C8)
Address: 4006_4000h base + Dh offset = 4006_400Dh
Bit

7

6

5

Read
Write
Reset

0

LOLRE

0

1

0

0

4

3

0
0

0

0
0

0

0

MCG_C8 field descriptions
Field
7
Reserved
6
LOLRE

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
PLL Loss of Lock Reset Enable
Determines if a interrupt or a reset request is made following a PLL loss of lock.
Table continues on the next page...

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Chapter 24 Multipurpose Clock Generator (MCG)

MCG_C8 field descriptions (continued)
Field

Description
0
1

Interrupt request is generated on a PLL loss of lock indication. The PLL loss of lock interrupt enable bit
must also be set to generate the interrupt request.
Generate a reset request on a PLL loss of lock indication.

5
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

4–1
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

0
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

24.3.13 MCG Control 9 Register (MCG_C9)
Address: 4006_4000h base + Eh offset = 4006_400Eh
Bit

Read
Write
Reset

7

6

5

4

3

2

0
0

0

1

0

0

0

1

0

0

0

0
0

0

0

0

MCG_C9 field descriptions
Field

Description

7–4
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

3–0
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

24.3.14 MCG Control 10 Register (MCG_C10)
Address: 4006_4000h base + Fh offset = 4006_400Fh
Bit

Read
Write
Reset

7

6

5

4

3

2

0
0

0

0
0

0

0

0

MCG_C10 field descriptions
Field

Description

7–4
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

3–0
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

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Functional Description

24.4 Functional Description
24.4.1 MCG mode state diagram
The nine states of the MCG are shown in the following figure and are described in Table
24-18. The arrows indicate the permitted MCG mode transitions.
Reset

FEI

FEE

FBI

FBE

BLPE

BLPI

PBE

PEE

Entered from any state when
the MCU enters Stop mode

Stop

Returns to the state that was active before
the MCU entered Stop mode, unless a
reset occurs while in Stop mode.

Figure 24-16. MCG mode state diagram

NOTE
• During exits from LLS or VLPS when the MCG is in PEE
mode, the MCG will reset to PBE clock mode and the
C1[CLKS] and S[CLKST] will automatically be set to
2’b10.
• If entering Normal Stop mode when the MCG is in PEE
mode with C5[PLLSTEN]=0, the MCG will reset to PBE
clock mode and C1[CLKS] and S[CLKST] will
automatically be set to 2’b10.

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Chapter 24 Multipurpose Clock Generator (MCG)

24.4.1.1 MCG modes of operation
The MCG operates in one of the following modes.
Note
The MCG restricts transitions between modes. For the
permitted transitions, see Figure 24-16.
Table 24-18. MCG modes of operation
Mode

Description

FLL Engaged Internal
(FEI)

FLL engaged internal (FEI) is the default mode of operation and is entered when all the following
condtions occur:
• C1[CLKS] bits are written to 00
• C1[IREFS] bit is written to 1
• C6[PLLS] bit is written to 0
In FEI mode, MCGOUTCLK is derived from the FLL clock (DCOCLK) that is controlled by the 32
kHz Internal Reference Clock (IRC). The FLL loop will lock the DCO frequency to the FLL factor, as
selected by C4[DRST_DRS] and C4[DMX32] bits, times the internal reference frequency. See the
C4[DMX32] bit description for more details. In FEI mode, the PLL is disabled in a low-power state
unless C5[PLLCLKEN0] is set.

FLL Engaged External
(FEE)

FLL engaged external (FEE) mode is entered when all the following conditions occur:
• C1[CLKS] bits are written to 00
• C1[IREFS] bit is written to 0
• C1[FRDIV] must be written to divide external reference clock to be within the range of 31.25
kHz to 39.0625 kHz
• C6[PLLS] bit is written to 0
In FEE mode, MCGOUTCLK is derived from the FLL clock (DCOCLK) that is controlled by the
external reference clock. The FLL loop will lock the DCO frequency to the FLL factor, as selected by
C4[DRST_DRS] and C4[DMX32] bits, times the external reference frequency, as specified by
C1[FRDIV] and C2[RANGE0]. See the C4[DMX32] bit description for more details. In FEE mode,
the PLL is disabled in a low-power state unless C5[PLLCLKEN0] is set.

FLL Bypassed Internal
(FBI)

FLL bypassed internal (FBI) mode is entered when all the following conditions occur:
• C1[CLKS] bits are written to 01
• C1[IREFS] bit is written to 1
• C6[PLLS] is written to 0
• C2[LP] is written to 0
In FBI mode, the MCGOUTCLK is derived either from the slow (32 kHz IRC) or fast (4 MHz IRC)
internal reference clock, as selected by the C2[IRCS] bit. The FLL is operational but its output is not
used. This mode is useful to allow the FLL to acquire its target frequency while the MCGOUTCLK is
driven from the C2[IRCS] selected internal reference clock. The FLL clock (DCOCLK) is controlled
by the slow internal reference clock, and the DCO clock frequency locks to a multiplication factor, as
selected by C4[DRST_DRS] and C4[DMX32] bits, times the internal reference frequency. See the
C4[DMX32] bit description for more details. In FBI mode, the PLL is disabled in a low-power state
unless C5[PLLCLKEN0] is set.
Table continues on the next page...

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Functional Description

Table 24-18. MCG modes of operation (continued)
Mode

Description

FLL Bypassed External FLL bypassed external (FBE) mode is entered when all the following conditions occur:
(FBE)
• C1[CLKS] bits are written to 10
• C1[IREFS] bit is written to 0
• C1[FRDIV] must be written to divide external reference clock to be within the range of 31.25
kHz to 39.0625 kHz.
• C6[PLLS] bit is written to 0
• C2[LP] is written to 0
In FBE mode, the MCGOUTCLK is derived from the external reference clock. The FLL is
operational but its output is not used. This mode is useful to allow the FLL to acquire its target
frequency while the MCGOUTCLK is driven from the external reference clock. The FLL clock
(DCOCLK) is controlled by the external reference clock, and the DCO clock frequency locks to a
multiplication factor, as selected by C4[DRST_DRS] and C4[DMX32] bits, times the divided external
reference frequency. See the C4[DMX32] bit description for more details. In FBI mode the PLL is
disabled in a low-power state unless C5[PLLCLKEN0] is set.
PLL Engaged External
(PEE)

PLL Engaged External (PEE) mode is entered when all the following conditions occur:
• C1[CLKS] bits are written to 00
• C1[IREFS] bit is written to 0
• C6[PLLS] bit is written to 1
In PEE mode, the MCGOUTCLK is derived from the PLL clock, which is controlled by the external
reference clock. The PLL clock frequency locks to a multiplication factor, as specified by C6[VDIV0],
times the external reference frequency, as specified by C5[PRDIV0]. The PLL's programmable
reference divider must be configured to produce a valid PLL reference clock. The FLL is disabled in
a low-power state.

PLL Bypassed External PLL Bypassed External (PBE) mode is entered when all the following conditions occur:
(PBE)
• C1[CLKS] bits are written to 10
• C1[IREFS] bit is written to 0
• C6[PLLS] bit is written to 1
• C2[LP] bit is written to 0
In PBE mode, MCGOUTCLK is derived from the external reference clock; the PLL is operational,
but its output clock is not used. This mode is useful to allow the PLL to acquire its target frequency
while MCGOUTCLK is driven from the external reference clock. The PLL clock frequency locks to a
multiplication factor, as specified by its [VDIV], times the PLL reference frequency, as specified by
its [PRDIV]. In preparation for transition to PEE, the PLL's programmable reference divider must be
configured to produce a valid PLL reference clock. The FLL is disabled in a low-power state.
Bypassed Low Power
Internal (BLPI)1

Bypassed Low Power Internal (BLPI) mode is entered when all the following conditions occur:
• C1[CLKS] bits are written to 01
• C1[IREFS] bit is written to 1
• C6[PLLS] bit is written to 0
• C2[LP] bit is written to 1
In BLPI mode, MCGOUTCLK is derived from the internal reference clock. The FLL is disabled and
PLL is disabled even if the C5[PLLCLKEN0] is set to 1.
Table continues on the next page...

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Table 24-18. MCG modes of operation (continued)
Mode

Description

Bypassed Low Power
External (BLPE)

Bypassed Low Power External (BLPE) mode is entered when all the following conditions occur:
• C1[CLKS] bits are written to 10
• C1[IREFS] bit is written to 0
• C2[LP] bit is written to 1
In BLPE mode, MCGOUTCLK is derived from the external reference clock. The FLL is disabled and
PLL is disabled even if the C5[PLLCLKEN0] is set to 1.

Stop

Entered whenever the MCU enters a Stop state. The power modes are chip specific. For power
mode assignments, see the chapter that describes how modules are configured and MCG behavior
during Stop recovery. Entering Stop mode, the FLL is disabled, and all MCG clock signals are static
except in the following case:
MCGPLLCLK is active in Normal Stop mode when PLLSTEN=1
MCGIRCLK is active in Normal Stop mode when all the following conditions become true:
• C1[IRCLKEN] = 1
• C1[IREFSTEN] = 1
NOTE:

• In VLPS Stop Mode, the MCGIRCLK can be programmed to stay enabled and
continue running if C1[IRCLKEN] = 1, C1[IREFSTEN]=1, and Fast IRC clock is
selected (C2[IRCS] = 1)

NOTE:

• When entering Low Power Stop modes (LLS or VLPS) from PEE mode, on exit the
MCG clock mode is forced to PBE clock mode. C1[CLKS] and S[CLKST] will be
configured to 2’b10if entering from PEE mode or to 2’b01 if entering from PEI mode,
C5[PLLSTEN0] will be force to 1'b0 and S[LOCK0] bit will be cleared without setting
S[LOLS0].
• When entering Normal Stop mode from PEE mode and if C5[PLLSTEN0]=0, on exit
the MCG clock mode is forced to PBE mode, the C1[CLKS] and S[CLKST] will be
configured to 2’b10 and S[LOCK0] bit will clear without setting S[LOLS0]. If
C5[PLLSTEN0]=1, the S[LOCK0] bit will not get cleared and on exit the MCG will
continue to run in PEE mode.

1. If entering VLPR mode, MCG has to be configured and enter BLPE mode or BLPI mode with the Fast IRC clock selected
(C2[IRCS]=1). After it enters VLPR mode, writes to any of the MCG control registers that can cause an MCG clock mode
switch to a non low power clock mode must be avoided.

NOTE
For the chip-specific modes of operation, see the power
management chapter of this MCU.

24.4.1.2 MCG mode switching
The C1[IREFS] bit can be changed at any time, but the actual switch to the newly
selected reference clocks is shown by the S[IREFST] bit. When switching between
engaged internal and engaged external modes, the FLL will begin locking again after the
switch is completed.
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The C1[CLKS] bits can also be changed at any time, but the actual switch to the newly
selected clock is shown by the S[CLKST] bits. If the newly selected clock is not
available, the previous clock will remain selected.
The C4[DRST_DRS] write bits can be changed at any time except when C2[LP] bit is 1.
If the C4[DRST_DRS] write bits are changed while in FLL engaged internal (FEI) or
FLL engaged external (FEE), the MCGOUTCLK will switch to the new selected DCO
range within three clocks of the selected DCO clock. After switching to the new DCO,
the FLL remains unlocked for several reference cycles. DCO startup time is equal to the
FLL acquisition time. After the selected DCO startup time is over, the FLL is locked. The
completion of the switch is shown by the C4[DRST_DRS] read bits.

24.4.2 Low Power Bit Usage
The C2[LP] bit is provided to allow the FLL or PLL to be disabled and thus conserve
power when these systems are not being used. The C4[DRST_DRS] can not be written
while C2[LP] bit is 1. However, in some applications, it may be desirable to enable the
FLL or PLL and allow it to lock for maximum accuracy before switching to an engaged
mode. Do this by writing C2[LP] to 0.

24.4.3 MCG Internal Reference Clocks
This module supports two internal reference clocks with nominal frequencies of 32 kHz
(slow IRC) and 4 MHz (fast IRC). The fast IRC frequency can be divided down by
programming of the FCRDIV to produce a frequency range of 32 kHz to 4 MHz.

24.4.3.1 MCG Internal Reference Clock
The MCG Internal Reference Clock (MCGIRCLK) provides a clock source for other onchip peripherals and is enabled when C1[IRCLKEN]=1. When enabled, MCGIRCLK is
driven by either the fast internal reference clock (4 MHz IRC which can be divided down
by the FRDIV factors) or the slow internal reference clock (32 kHz IRC). The IRCS
clock frequency can be re-targeted by trimming the period of its IRCS selected internal
reference clock. This can be done by writing a new trim value to the
C3[SCTRIM]:C4[SCFTRIM] bits when the slow IRC clock is selected or by writing a
new trim value to the C4[FCTRIM] bits when the fast IRC clock is selected. The internal
reference clock period is proportional to the trim value written.
C3[SCTRIM]:C4[SCFTRIM] (if C2[IRCS]=0) and C4[FCTRIM] (if C2[IRCS]=1) bits

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affect the MCGOUTCLK frequency if the MCG is in FBI or BLPI modes.
C3[SCTRIM]:C4[SCFTRIM] (if C2[IRCS]=0) bits also affect the MCGOUTCLK
frequency if the MCG is in FEI mode.
Additionally, this clock can be enabled in Stop mode by setting C1[IRCLKEN] and
C1[IREFSTEN], otherwise this clock is disabled in Stop mode.

24.4.4 External Reference Clock
The MCG module can support an external reference clock in all modes. See the device
datasheet for external reference frequency range. When C1[IREFS] is set, the external
reference clock will not be used by the FLL or PLL. In these modes, the frequency can be
equal to the maximum frequency the chip-level timing specifications will support.
If any of the CME bits are asserted the slow internal reference clock is enabled along
with the enabled external clock monitor. For the case when C6[CME0]=1, a loss of clock
is detected if the OSC0 external reference falls below a minimum frequency (floc_high or
floc_low depending on C2[RANGE0]).
All clock monitors must be disabled before VLPR or VLPW power modes are entered.
Upon detect of a loss of clock event, the MCU generates a system reset if the respective
LOCRE bit is set. Otherwise the MCG sets the respective LOCS bit and the MCG
generates a LOCS interrupt request. In the case where a OSC0 loss of clock is detected,
the PLL LOCK status bit is cleared if the OSC clock that is lost was selected as the PLL
reference clock.

24.4.5 MCG Fixed frequency clock
The MCG Fixed Frequency Clock (MCGFFCLK) provides a fixed frequency clock
source for other on-chip peripherals; see the block diagram. This clock is driven by either
the slow clock from the internal reference clock generator or the external reference clock
from the Crystal Oscillator, divided by the FLL reference clock divider. The source of
MCGFFCLK is selected by C1[IREFS].
This clock is synchronized to the peripheral bus clock and is valid only when its
frequency is not more than 1/8 of the MCGOUTCLK frequency. When it is not valid, it is
disabled and held high. The MCGFFCLK is not available when the MCG is in BLPI
mode. This clock is also disabled in Stop mode. The FLL reference clock must be set
within the valid frequency range for the MCGFFCLK.

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24.4.6 MCG PLL clock
The MCG PLL Clock (MCGPLLCLK) is available depending on the device's
configuration of the MCG module. For more details, see the clock distribution chapter of
this MCU. The MCGPLLCLK is prevented from coming out of the MCG until it is
enabled and S[LOCK0] is set.

24.4.7 MCG Auto TRIM (ATM)
The MCG Auto Trim (ATM) is a MCG feature that when enabled, it configures the MCG
hardware to automatically trim the MCG Internal Reference Clocks using an external
clock as a reference. The selection between which MCG IRC clock gets tested and
enabled is controlled by the ATC[ATMS] control bit (ATC[ATMS]=0 selects the 32 kHz
IRC and ATC[ATMS]=1 selects the 4 MHz IRC). If 4 MHz IRC is selected for the ATM,
a divide by 128 is enabled to divide down the 4 MHz IRC to a range of 31.250 kHz.
When MCG ATM is enabled by writing ATC[ATME] bit to 1, The ATM machine will
start auto trimming the selected IRC clock. During the autotrim process, ATC[ATME]
will remain asserted and will deassert after ATM is completed or an abort occurs. The
MCG ATM is aborted if a write to any of the following control registers is detected : C1,
C3, C4, or ATC or if Stop mode is entered. If an abort occurs, ATC[ATMF] fail flag is
asserted.
The ATM machine uses the bus clock as the external reference clock to perform the IRC
auto-trim. Therefore, it is required that the MCG is configured in a clock mode where the
reference clock used to generate the system clock is the external reference clock such as
FBE clock mode. The MCG must not be configured in a clock mode where selected IRC
ATM clock is used to generate the system clock. The bus clock is also required to be
running with in the range of 8–16 MHz.
To perform the ATM on the selected IRC, the ATM machine uses the successive
approximation technique to adjust the IRC trim bits to generate the desired IRC trimmed
frequency. The ATM SARs each of the ATM IRC trim bits starting with the MSB. For
each trim bit test, the ATM uses a pulse that is generated by the ATM selected IRC clock
to enable a counter that counts number of ATM external clocks. At end of each trim bit,
the ATM external counter value is compared to the ATCV[15:0] register value. Based on
the comparison result, the ATM trim bit under test will get cleared or stay asserted. This
is done until all trim bits have been tested by ATM SAR machine.

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Before the ATM can be enabled, the ATM expected count needs to be derived and stored
into the ATCV register. The ATCV expected count is derived based on the required
target Internal Reference Clock (IRC) frequency, and the frequency of the external
reference clock using the following formula:
ATCV

• Fr = Target Internal Reference Clock (IRC) Trimmed Frequency
• Fe = External Clock Frequency
If the auto trim is being performed on the 4 MHz IRC, the calculated expected count
value must be multiplied by 128 before storing it in the ATCV register. Therefore, the
ATCV Expected Count Value for trimming the 4 MHz IRC is calculated using the
following formula.
(128)

24.5 Initialization / Application information
This section describes how to initialize and configure the MCG module in an application.
The following sections include examples on how to initialize the MCG and properly
switch between the various available modes.

24.5.1 MCG module initialization sequence
The MCG comes out of reset configured for FEI mode. The internal reference will
stabilize in tirefsts microseconds before the FLL can acquire lock. As soon as the internal
reference is stable, the FLL will acquire lock in tfll_acquire milliseconds.

24.5.1.1 Initializing the MCG
Because the MCG comes out of reset in FEI mode, the only MCG modes that can be
directly switched to upon reset are FEE, FBE, and FBI modes (see Figure 24-16).
Reaching any of the other modes requires first configuring the MCG for one of these
three intermediate modes. Care must be taken to check relevant status bits in the MCG
status register reflecting all configuration changes within each mode.
To change from FEI mode to FEE or FBE modes, follow this procedure:
1. Enable the external clock source by setting the appropriate bits in C2 register.
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2. Write to C1 register to select the clock mode.
• If entering FEE mode, set C1[FRDIV] appropriately, clear the C1[IREFS] bit to
switch to the external reference, and leave the C1[CLKS] bits at 2'b00 so that the
output of the FLL is selected as the system clock source.
• If entering FBE, clear the C1[IREFS] bit to switch to the external reference and
change the C1[CLKS] bits to 2'b10 so that the external reference clock is
selected as the system clock source. The C1[FRDIV] bits should also be set
appropriately here according to the external reference frequency to keep the FLL
reference clock in the range of 31.25 kHz to 39.0625 kHz. Although the FLL is
bypassed, it is still on in FBE mode.
• The internal reference can optionally be kept running by setting the
C1[IRCLKEN] bit. This is useful if the application will switch back and forth
between internal and external modes. For minimum power consumption, leave
the internal reference disabled while in an external clock mode.
3. Once the proper configuration bits have been set, wait for the affected bits in the
MCG status register to be changed appropriately, reflecting that the MCG has moved
into the proper mode.
• If the MCG is in FEE, FBE, PEE, PBE, or BLPE mode, and C2[EREFS0] was
also set in step 1, wait here for S[OSCINIT0] bit to become set indicating that
the external clock source has finished its initialization cycles and stabilized.
• If in FEE mode, check to make sure the S[IREFST] bit is cleared before moving
on.
• If in FBE mode, check to make sure the S[IREFST] bit is cleared and S[CLKST]
bits have changed to 2'b10 indicating the external reference clock has been
appropriately selected. Although the FLL is bypassed, it is still on in FBE mode.
4. Write to the C4 register to determine the DCO output (MCGFLLCLK) frequency
range.
• By default, with C4[DMX32] cleared to 0, the FLL multiplier for the DCO
output is 640. For greater flexibility, if a mid-low-range FLL multiplier of 1280
is desired instead, set C4[DRST_DRS] bits to 2'b01 for a DCO output frequency
of 40 MHz. If a mid high-range FLL multiplier of 1920 is desired instead, set the
C4[DRST_DRS] bits to 2'b10 for a DCO output frequency of 60 MHz. If a highrange FLL multiplier of 2560 is desired instead, set the C4[DRST_DRS] bits to
2'b11 for a DCO output frequency of 80 MHz.

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Chapter 24 Multipurpose Clock Generator (MCG)

• When using a 32.768 kHz external reference, if the maximum low-range DCO
frequency that can be achieved with a 32.768 kHz reference is desired, set
C4[DRST_DRS] bits to 2'b00 and set C4[DMX32] bit to 1. The resulting DCO
output (MCGOUTCLK) frequency with the new multiplier of 732 will be 24
MHz.
• When using a 32.768 kHz external reference, if the maximum mid-range DCO
frequency that can be achieved with a 32.768 kHz reference is desired, set
C4[DRST_DRS] bits to 2'b01 and set C4[DMX32] bit to 1. The resulting DCO
output (MCGOUTCLK) frequency with the new multiplier of 1464 will be 48
MHz.
• When using a 32.768 kHz external reference, if the maximum mid high-range
DCO frequency that can be achieved with a 32.768 kHz reference is desired, set
C4[DRST_DRS] bits to 2'b10 and set C4[DMX32] bit to 1. The resulting DCO
output (MCGOUTCLK) frequency with the new multiplier of 2197 will be 72
MHz.
• When using a 32.768 kHz external reference, if the maximum high-range DCO
frequency that can be achieved with a 32.768 kHz reference is desired, set
C4[DRST_DRS] bits to 2'b11 and set C4[DMX32] bit to 1. The resulting DCO
output (MCGOUTCLK) frequency with the new multiplier of 2929 will be 96
MHz.
5. Wait for the FLL lock time to guarantee FLL is running at new C4[DRST_DRS] and
C4[DMX32] programmed frequency.
To change from FEI clock mode to FBI clock mode, follow this procedure:
1. Change C1[CLKS] bits in C1 register to 2'b01 so that the internal reference clock is
selected as the system clock source.
2. Wait for S[CLKST] bits in the MCG status register to change to 2'b01, indicating
that the internal reference clock has been appropriately selected.
3. Write to the C2 register to determine the IRCS output (IRCSCLK) frequency range.
• By default, with C2[IRCS] cleared to 0, the IRCS selected output clock is the
slow internal reference clock (32 kHz IRC). If the faster IRC is desired, set
C2[IRCS] bit to 1 for a IRCS clock derived from the 4 MHz IRC source.

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24.5.2 Using a 32.768 kHz reference
In FEE and FBE modes, if using a 32.768 kHz external reference, at the default FLL
multiplication factor of 640, the DCO output (MCGFLLCLK) frequency is 20.97 MHz at
low-range. If C4[DRST_DRS] bits are set to 2'b01, the multiplication factor is doubled to
1280, and the resulting DCO output frequency is 41.94 MHz at mid-low-range. If
C4[DRST_DRS] bits are set to 2'b10, the multiplication factor is set to 1920, and the
resulting DCO output frequency is 62.91 MHz at mid high-range. If C4[DRST_DRS] bits
are set to 2'b11, the multiplication factor is set to 2560, and the resulting DCO output
frequency is 83.89 MHz at high-range.
In FBI and FEI modes, setting C4[DMX32] bit is not recommended. If the internal
reference is trimmed to a frequency above 32.768 kHz, the greater FLL multiplication
factor could potentially push the microcontroller system clock out of specification and
damage the part.

24.5.3 MCG mode switching
When switching between operational modes of the MCG, certain configuration bits must
be changed in order to properly move from one mode to another. Each time any of these
bits are changed (C6[PLLS], C1[IREFS], C1[CLKS], C2[IRCS], or C2[EREFS0]), the
corresponding bits in the MCG status register (PLLST, IREFST, CLKST, IRCST, or
OSCINIT) must be checked before moving on in the application software.
Additionally, care must be taken to ensure that the reference clock divider (C1[FRDIV]
and C5[PRDIV0]) is set properly for the mode being switched to. For instance, in PEE
mode, if using a 4 MHz crystal, C5[PRDIV0] must be set to 5'b000 (divide-by-1) or
5'b001 (divide -by-2) to divide the external reference down to the required frequency
between 2 and 4 MHz.
In FBE, FEE, FBI, and FEI modes, at any time, the application can switch the FLL
multiplication factor between 640, 1280, 1920, and 2560 with C4[DRST_DRS] bits.
Writes to C4[DRST_DRS] bits will be ignored if C2[LP]=1.
The table below shows MCGOUTCLK frequency calculations using C1[FRDIV],
C5[PRDIV0], and C6[VDIV0] settings for each clock mode.
Table 24-19. MCGOUTCLK Frequency Calculation Options
Clock Mode

fMCGOUTCLK1

Note

FEI (FLL engaged internal)

(fint * F)

Typical fMCGOUTCLK = 21 MHz
immediately after reset.

FEE (FLL engaged external)

(fext / FLL_R) *F

fext / FLL_R must be in the range of
31.25 kHz to 39.0625 kHz

Table continues on the next page...

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Table 24-19. MCGOUTCLK Frequency Calculation Options
(continued)
Clock Mode

fMCGOUTCLK1

Note

FBE (FLL bypassed external)

OSCCLK

OSCCLK / FLL_R must be in the
range of 31.25 kHz to 39.0625 kHz

FBI (FLL bypassed internal)

MCGIRCLK

Selectable between slow and fast
IRC

PEE (PLL engaged external)

(OSCCLK / PLL_R) * M

OSCCLK / PLL_R must be in the
range of 2 – 4 MHz

PBE (PLL bypassed external)

OSCCLK

OSCCLK / PLL_R must be in the
range of 2 – 4 MHz

BLPI (Bypassed low power internal)

MCGIRCLK

Selectable between slow and fast
IRC

BLPE (Bypassed low power external)

OSCCLK

1. FLL_R is the reference divider selected by the C1[FRDIV] bits, PLL_R is the reference divider selected by C5[PRDIV0]
bits, F is the FLL factor selected by C4[DRST_DRS] and C4[DMX32] bits, and M is the multiplier selected by C6[VDIV0]
bits.

This section will include three mode switching examples using an 4 MHz external
crystal. If using an external clock source less than 2 MHz, the MCG must not be
configured for any of the PLL modes (PEE and PBE).

24.5.3.1 Example 1: Moving from FEI to PEE mode: External Crystal =
4 MHz, MCGOUTCLK frequency = 48 MHz
In this example, the MCG will move through the proper operational modes from FEI to
PEE to achieve 48 MHz MCGOUTCLK frequency from 4 MHz external crystal
reference. First, the code sequence will be described. Then there is a flowchart that
illustrates the sequence.
1. First, FEI must transition to FBE mode:
a. C2 = 0x1C
• C2[RANGE0] set to 2'b01 because the frequency of 4 MHz is within the
high frequency range.
• C2[HGO0] set to 1 to configure the crystal oscillator for high gain operation.
• C2[EREFS0] set to 1, because a crystal is being used.
b. C1 = 0x90
• C1[CLKS] set to 2'b10 to select external reference clock as system clock
source
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• C1[FRDIV] set to 3'b010, or divide-by-128 because 4 MHz / 128 = 31.25
kHz which is in the 31.25 kHz to 39.0625 kHz range required by the FLL
• C1[IREFS] cleared to 0, selecting the external reference clock and enabling
the external oscillator.
c. Loop until S[OSCINIT0] is 1, indicating the crystal selected by C2[EREFS0] has
been initialized.
d. Loop until S[IREFST] is 0, indicating the external reference is the current source
for the reference clock.
e. Loop until S[CLKST] is 2'b10, indicating that the external reference clock is
selected to feed MCGOUTCLK.
2. Then configure C5[PRDIV0] to generate correct PLL reference frequency.
a. C5 = 0x01
• C5[PRDIV0] set to 5'b001, or divide-by-2 resulting in a pll reference
frequency of 4 MHz/2 = 2 MHz.
3. Then, FBE must transition either directly to PBE mode or first through BLPE mode
and then to PBE mode:
a. BLPE: If a transition through BLPE mode is desired, first set C2[LP] to 1.
b. BLPE/PBE: C6 = 0x40
• C6[PLLS] set to 1, selects the PLL. At this time, with a C1[PRDIV] value of
2'b001, the PLL reference divider is 2 (see PLL External Reference Divide
Factor table), resulting in a reference frequency of 4 MHz/ 2 = 2 MHz. In
BLPE mode, changing the C6[PLLS] bit only prepares the MCG for PLL
usage in PBE mode.
• C6[VDIV0] set to 5'b0000, or multiply-by-24 because 2 MHz reference * 24
= 48 MHz. In BLPE mode, the configuration of the VDIV bits does not
matter because the PLL is disabled. Changing them only sets up the multiply
value for PLL usage in PBE mode.
c. BLPE: If transitioning through BLPE mode, clear C2[LP] to 0 here to switch to
PBE mode.
d. PBE: Loop until S[PLLST] is set, indicating that the current source for the PLLS
clock is the PLL.
e. PBE: Then loop until S[LOCK0] is set, indicating that the PLL has acquired
lock.
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4. Lastly, PBE mode transitions into PEE mode:
a. C1 = 0x10
• C1[CLKS] set to 2'b00 to select the output of the PLL as the system clock
source.
b. Loop until S[CLKST] are 2'b11, indicating that the PLL output is selected to
feed MCGOUTCLK in the current clock mode.
• Now, with PRDIV0 of divide-by-2, and C6[VDIV0] of multiply-by-24,
MCGOUTCLK = [(4 MHz / 2) * 24] = 48 MHz.

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Initialization / Application information
START
IN FEI MODE
C6 = 0x40

C2 = 0x1C
IN
BLPE MODE ?
(S[LP]=1)
C1 = 0x90

NO

YES
C2 = 0x1C
(S[LP]=0)

NO
CHECK
S[OSCINIT] = 1?
CHECK
S[PLLST] = 1?

YES

CHECK
S[IREFST] = 0?

NO

YES
NO

CHECK
S[LOCK] = 1?

YES

CHECK
NO
S[CLKST] = %10?

NO

YES
C1 = 0x10

YES
C5 = 0x01
(C5[VDIV] = 1)

ENTER
BLPE MODE ?

CHECK
S[CLKST] = %11?

NO

NO

YES

CONTINUE
YES

IN PEE MODE

C2 = 0x1E
(C2[LP] = 1)

Figure 24-17. Flowchart of FEI to PEE mode transition using an 4 MHz crystal
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Chapter 24 Multipurpose Clock Generator (MCG)

24.5.3.2 Example 2: Moving from PEE to BLPI mode: MCGOUTCLK
frequency =32 kHz
In this example, the MCG will move through the proper operational modes from PEE
mode with a 4 MHz crystal configured for a 48 MHz MCGOUTCLK frequency (see
previous example) to BLPI mode with a 32 kHz MCGOUTCLK frequency. First, the
code sequence will be described. Then there is a flowchart that illustrates the sequence.
1. First, PEE must transition to PBE mode:
a. C1 = 0x90
• C1[CLKS] set to 2'b10 to switch the system clock source to the external
reference clock.
b. Loop until S[CLKST] are 2'b10, indicating that the external reference clock is
selected to feed MCGOUTCLK.
2. Then, PBE must transition either directly to FBE mode or first through BLPE mode
and then to FBE mode:
a. BLPE: If a transition through BLPE mode is desired, first set C2[LP] to 1.
b. BLPE/FBE: C6 = 0x00
• C6[PLLS] clear to 0 to select the FLL. At this time, with C1[FRDIV] value
of 3'b010, the FLL divider is set to 128, resulting in a reference frequency of
4 MHz / 128 = 31.25 kHz. If C1[FRDIV] was not previously set to 3'b010
(necessary to achieve required 31.25–39.06 kHz FLL reference frequency
with an 4 MHz external source frequency), it must be changed prior to
clearing C6[PLLS] bit. In BLPE mode,changing this bit only prepares the
MCG for FLL usage in FBE mode. With C6[PLLS] = 0, the C6[VDIV0]
value does not matter.
c. BLPE: If transitioning through BLPE mode, clear C2[LP] to 0 here to switch to
FBE mode.
d. FBE: Loop until S[PLLST] is cleared, indicating that the current source for the
PLLS clock is the FLL.
3. Next, FBE mode transitions into FBI mode:
a. C1 = 0x54
• C1[CLKS] set to 2'b01 to switch the system clock to the internal reference
clock.
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• C1[IREFS] set to 1 to select the internal reference clock as the reference
clock source.
• C1[FRDIV] remain unchanged because the reference divider does not affect
the internal reference.
b. Loop until S[IREFST] is 1, indicating the internal reference clock has been
selected as the reference clock source.
c. Loop until S[CLKST] are 2'b01, indicating that the internal reference clock is
selected to feed MCGOUTCLK.
4. Lastly, FBI transitions into BLPI mode.
a. C2 = 0x02
• C2[LP] is 1
• C2[RANGE0], C2[HGO0], C2[EREFS0], C1[IRCLKEN], and
C1[IREFSTEN] bits are ignored when the C1[IREFS] bit is set. They can
remain set, or be cleared at this point.

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Chapter 24 Multipurpose Clock Generator (MCG)
START
IN PEE MODE

C1 = 0x90
CHECK
S[PLLST] = 0?
NO
CHECK
S[CLKST] = %10 ?

YES
C1 = 0x54

YES

ENTER

NO

NO
CHECK
S[IREFST] = 0?

BLPE MODE ?

YES

NO

YES

C2 = 0x1E
(C2[LP] = 1)
CHECK
S[CLKST] = %01?

NO

C6 = 0x00
YES
C2 = 0x02

IN
BLPE MODE ?
(C2[LP]=1)

NO

CONTINUE

YES

IN BLPI MODE

C2 = 0x1C
(C2[LP] = 0)

Figure 24-18. Flowchart of PEE to BLPI mode transition using an 4 MHz crystal

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24.5.3.3 Example 3: Moving from BLPI to FEE mode
In this example, the MCG will move through the proper operational modes from BLPI
mode at a 32 kHz MCGOUTCLK frequency running off the internal reference clock (see
previous example) to FEE mode using a 4 MHz crystal configured for a 20 MHz
MCGOUTCLK frequency. First, the code sequence will be described. Then there is a
flowchart that illustrates the sequence.
1. First, BLPI must transition to FBI mode.
a. C2 = 0x00
• C2[LP] is 0
2. Next, FBI will transition to FEE mode.
a. C2 = 0x1C
• C2[RANGE0] set to 2'b01 because the frequency of 4 MHz is within the
high frequency range.
• C2[HGO0] set to 1 to configure the crystal oscillator for high gain operation.
• C2[EREFS0] set to 1, because a crystal is being used.
b. C1 = 0x10
• C1[CLKS] set to 2'b00 to select the output of the FLL as system clock
source.
• C1[FRDIV] remain at 3'b010, or divide-by-128 for a reference of 4 MHz /
128 = 31.25 kHz.
• C1[IREFS] cleared to 0, selecting the external reference clock.
c. Loop until S[OSCINIT0] is 1, indicating the crystal selected by the C2[EREFS0]
bit has been initialized.
d. Loop until S[IREFST] is 0, indicating the external reference clock is the current
source for the reference clock.
e. Loop until S[CLKST] are 2'b00, indicating that the output of the FLL is selected
to feed MCGOUTCLK.
f. Now, with a 31.25 kHz reference frequency, a fixed DCO multiplier of 640,
MCGOUTCLK = 31.25 kHz * 640 / 1 = 20 MHz.
g. At this point, by default, the C4[DRST_DRS] bits are set to 2'b00 and
C4[DMX32] is cleared to 0. If the MCGOUTCLK frequency of 40 MHz is
desired instead, set the C4[DRST_DRS] bits to 0x01 to switch the FLL
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Chapter 24 Multipurpose Clock Generator (MCG)

multiplication factor from 640 to 1280. To return the MCGOUTCLK frequency
to 20 MHz, set C4[DRST_DRS] bits to 2'b00 again, and the FLL multiplication
factor will switch back to 640.
START
IN BLPI MODE
CHECK
NO
S[IREFST] = 0?
C2 =0x00
YES
C2 = 0x1C
NO
CHECK
S[CLKST] = %00?
C1 =0x10

YES
CONTINUE

CHECK
S[OSCINIT] = 1 ?

NO

IN FEE MODE

YES

Figure 24-19. Flowchart of BLPI to FEE mode transition using an 4 MHz crystal

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Chapter 25
Oscillator (OSC)
25.1 Introduction
NOTE
For the chip-specific implementation details of this module's
instances see the chip configuration information.
The OSC module is a crystal oscillator. The module, in conjunction with an external
crystal or resonator, generates a reference clock for the MCU.

25.2 Features and Modes
Key features of the module are:
• Supports 32 kHz crystals (Low Range mode)
• Voltage and frequency filtering to guarantee clock frequency and stability
• Optionally external input bypass clock from EXTAL signal directly
• One clock for MCU clock system
• Two clocks for on-chip peripherals that can work in Stop modes
Functional Description describes the module's operation in more detail.

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Block Diagram

25.3 Block Diagram
The OSC module uses a crystal or resonator to generate three filtered oscillator clock
signals. Three clocks are output from OSC module: OSCCLK for MCU system,
OSCERCLK for on-chip peripherals, and OSC32KCLK. The OSCCLK can only work in
run mode. OSCERCLK and OSC32KCLK can work in low power modes. For the clock
source assignments, refer to the clock distribution information of this MCU.
Refer to the chip configuration chapter for the external reference clock source in this
MCU.
The following figure shows the block diagram of the OSC module.
EXTAL

XTAL

OSC_CLK_OUT
Mux

OSC Clock Enable

ERCLKEN

XTL_CLK

Range selections
Low Power config

Oscillator Circuits

OSCERCLK

EN
OSC32KCLK

ERCLKEN

OSC clock selection

EREFSTEN

OSC_EN

4096
Counter

CNT_DONE_4096

Control and Decoding
logic

OSCCLK

STOP

Figure 25-1. OSC Module Block Diagram

25.4 OSC Signal Descriptions
The following table shows the user-accessible signals available for the OSC module.
Refer to signal multiplexing information for this MCU for more details.

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Chapter 25 Oscillator (OSC)

Table 25-1. OSC Signal Descriptions
Signal

Description

EXTAL

External clock/Oscillator input

I

Oscillator output

O

XTAL

I/O

25.5 External Crystal / Resonator Connections
The connections for a crystal/resonator frequency reference are shown in the following
figures. When using low-frequency, low-power mode, the only external component is the
crystal or ceramic resonator itself. In the other oscillator modes, load capacitors (Cx, Cy)
and feedback resistor (RF) are required. The following table shows all possible
connections.
Table 25-2. External Caystal/Resonator Connections
Oscillator Mode

Connections

Low-frequency (32 kHz), low-power

Connection 11

Low-frequency (32 kHz), high-gain

Connection 2/Connection 32

High-frequency (3~32 MHz), low-power

Connection 31

High-frequency (3~32 MHz), high-gain

Connection 3

1. With the low-power mode, the oscillator has the internal feedback resistor RF. Therefore, the feedback resistor must not be
externally with the Connection 3.
2. When the load capacitors (Cx, Cy) are greater than 30 pF, use Connection 3.

OSC
XTAL

VSS

EXTAL

Crystal or Resonator

Figure 25-2. Crystal/Ceramic Resonator Connections - Connection 1

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External Clock Connections

OSC
XTAL

EXTAL

VSS

RF

Crystal or Resonator

Figure 25-3. Crystal/Ceramic Resonator Connections - Connection 2

NOTE
Connection 1 and Connection 2 should use internal capacitors
as the load of the oscillator by configuring the CR[SCxP] bits.

OSC
XTAL

EXTAL

VSS

Cx

Cy

RF

Crystal or Resonator

Figure 25-4. Crystal/Ceramic Resonator Connections - Connection 3

25.6 External Clock Connections
In external clock mode, the pins can be connected as shown below.
NOTE
XTAL can be used as a GPIO when the GPIO alternate function
is configured for it.

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Chapter 25 Oscillator (OSC)

OSC
XTAL

EXTAL

VSS

Clock Input

I/O

Figure 25-5. External Clock Connections

25.7 Memory Map/Register Definitions
Some oscillator module register bits are typically incorporated into other peripherals such
as MCG or SIM.

25.7.1 OSC Memory Map/Register Definition
OSC memory map
Absolute
address
(hex)
4006_5000

Width
Access
(in bits)

Register name
OSC Control Register (OSC0_CR)

8

Reset value

Section/
page

00h

25.71.1/409

R/W

25.71.1 OSC Control Register (OSCx_CR)
NOTE
After OSC is enabled and starts generating the clocks, the
configurations such as low power and frequency range, must
not be changed.
Address: 4006_5000h base + 0h offset = 4006_5000h
Bit

Read
Write
Reset

7

6

ERCLKEN

0

0

0

5

3

2

1

0

EREFSTEN

0

4

SC2P

SC4P

SC8P

SC16P

0

0

0

0

0

0

OSCx_CR field descriptions
Field
7
ERCLKEN

Description
External Reference Enable
Enables external reference clock (OSCERCLK).
Table continues on the next page...

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Functional Description

OSCx_CR field descriptions (continued)
Field

Description
0
1

6
Reserved
5
EREFSTEN

This field is reserved.
This read-only field is reserved and always has the value 0.
External Reference Stop Enable
Controls whether or not the external reference clock (OSCERCLK) remains enabled when MCU enters
Stop mode.
0
1

4
Reserved
3
SC2P

Oscillator 2 pF Capacitor Load Configure
Configures the oscillator load.

Configures the oscillator load.
Disable the selection.
Add 4 pF capacitor to the oscillator load.

Oscillator 8 pF Capacitor Load Configure
Configures the oscillator load.
0
1

0
SC16P

Disable the selection.
Add 2 pF capacitor to the oscillator load.

Oscillator 4 pF Capacitor Load Configure

0
1
1
SC8P

External reference clock is disabled in Stop mode.
External reference clock stays enabled in Stop mode if ERCLKEN is set before entering Stop mode.

This field is reserved.
This read-only field is reserved and always has the value 0.

0
1
2
SC4P

External reference clock is inactive.
External reference clock is enabled.

Disable the selection.
Add 8 pF capacitor to the oscillator load.

Oscillator 16 pF Capacitor Load Configure
Configures the oscillator load.
0
1

Disable the selection.
Add 16 pF capacitor to the oscillator load.

25.8 Functional Description
This following sections provide functional details of the module.

25.8.1 OSC Module States
The states of the OSC module are shown in the following figure. The states and their
transitions between each other are described in this section.
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Chapter 25 Oscillator (OSC)

Off
Oscillator OFF
OSC_CLK_OUT = Static

OSCCLK

not requested

OSCCLK requested

OSCCLK requested

&&

&&

Select OSC internal clock

Select clock from EXTAL signal

Start-Up

External Clock Mode

Oscillator ON, not yet stable
OSC_CLK_OUT = Static

Oscillator ON
OSC_CLK_OUT = EXTAL

CNT_DONE_4096

Stable
Oscillator ON, Stable
OSC_CLK_OUT = XTL_CLK

Figure 25-8. OSC Module State Diagram

NOTE
XTL_CLK is the clock generated internally from OSC circuits.

25.8.1.1 Off
The OSC enters the Off state when the system does not require OSC clocks. Upon
entering this state, XTL_CLK is static unless OSC is configured to select the clock from
the EXTAL pad by clearing the external reference clock selection bit. For details
regarding the external reference clock source in this MCU, refer to the chip configuration
chapter. The EXTAL and XTAL pins are also decoupled from all other oscillator
circuitry in this state. The OSC module circuitry is configured to draw minimal current.

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Functional Description

25.8.1.2 Oscillator Start-Up
The OSC enters start-up state when it is configured to generate clocks (internally the
OSC_EN transitions high) using the internal oscillator circuits by setting the external
reference clock selection bit. In this state, the OSC module is enabled and oscillations are
starting up, but have not yet stabilized. When the oscillation amplitude becomes large
enough to pass through the input buffer, XTL_CLK begins clocking the counter. When
the counter reaches 4096 cycles of XTL_CLK, the oscillator is considered stable and
XTL_CLK is passed to the output clock OSC_CLK_OUT.

25.8.1.3 Oscillator Stable
The OSC enters stable state when it is configured to generate clocks (internally the
OSC_EN transitions high) using the internal oscillator circuits by setting the external
reference clock selection bit and the counter reaches 4096 cycles of XTL_CLK (when
CNT_DONE_4096 is high). In this state, the OSC module is producing a stable output
clock on OSC_CLK_OUT. Its frequency is determined by the external components being
used.

25.8.1.4 External Clock Mode
The OSC enters external clock state when it is enabled and external reference clock
selection bit is cleared. For details regarding external reference clock source in this MCU,
refer to the chip configuration chapter. In this state, the OSC module is set to buffer (with
hysteresis) a clock from EXTAL onto the OSC_CLK_OUT. Its frequency is determined
by the external clock being supplied.

25.8.2 OSC Module Modes
The OSC is a Pierce-type oscillator that supports external crystals or resonators operating
over the frequency ranges shown in Table 25-7. These modes assume the following
conditions: OSC is enabled to generate clocks (OSC_EN=1), configured to generate
clocks internally (MCG_C2[EREFS] = 1), and some or one of the other peripherals
(MCG, Timer, and so on) is configured to use the oscillator output clock
(OSC_CLK_OUT).

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Chapter 25 Oscillator (OSC)

Table 25-7. Oscillator Modes
Mode

Frequency Range

High-frequency mode1, high-gain

fosc_hi_1 (3 MHz) up to fosc_hi_1 (8 MHz)

High-frequency mode1, low-power

NOTE
For information about low power modes of operation used in
this chip and their alignment with some OSC modes, refer to
the chip's Power Management details.

25.8.2.1 Low-Frequency, Low-Power Mode
In low-frequency, low-power mode, the oscillator uses a gain control loop to minimize
power consumption. As the oscillation amplitude increases, the amplifier current is
reduced. This continues until a desired amplitude is achieved at steady-state. This mode
provides low pass frequency filtering as well as hysteresis for voltage filtering and
converts the output to logic levels. In this mode, the internal capacitors could be used, the
internal feedback resistor is connected, and no external resistor should be used.
In this mode, the amplifier inputs, gain-control input, and input buffer input are all
capacitively coupled for leakage tolerance (not sensitive to the DC level of EXTAL).
Also in this mode, all external components except for the resonator itself are integrated,
which includes the load capacitors and feeback resistor that biases EXTAL.

25.8.3 Counter
The oscillator output clock (OSC_CLK_OUT) is gated off until the counter has detected
4096 cycles of its input clock (XTL_CLK). After 4096 cycles are completed, the counter
passes XTL_CLK onto OSC_CLK_OUT. This counting time-out is used to guarantee
output clock stability.

25.8.4 Reference Clock Pin Requirements
The OSC module requires use of both the EXTAL and XTAL pins to generate an output
clock in Oscillator mode, but requires only the EXTAL pin in External clock mode. The
EXTAL and XTAL pins are available for I/O. For the implementation of these pins on
this device, refer to the Signal Multiplexing chapter.
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25.9 Reset
There is no reset state associated with the OSC module. The counter logic is reset when
the OSC is not configured to generate clocks.
There are no sources of reset requests for the OSC module.

25.10 Low Power Modes Operation
When the MCU enters Stop modes, the OSC is functional depending on ERCLKEN and
EREFSETN bit settings. If both these bits are set, the OSC is in operation. In Low
Leakage Stop (LLS) modes, the OSC holds all register settings. If ERCLKEN and
EREFSTEN bits are set before entry to Low Leakage Stop modes, the OSC is still
functional in these modes. After waking up from Very Low Leakage Stop (VLLSx)
modes, all OSC register bits are reset and initialization is required through software.

25.11 Interrupts
The OSC module does not generate any interrupts.

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Chapter 26
Flash Memory Controller (FMC)
26.1 Introduction
The Flash Memory Controller (FMC) is a memory acceleration unit that provides:
• an interface between bus masters and the 32-bit program flash memory.
• a buffer and a cache that can accelerate program flash memory data transfers.

26.1.1 Overview
The Flash Memory Controller manages the interface between bus masters and the 32-bit
program flash memory. The FMC receives status information detailing the configuration
of the flash memory and uses this information to ensure a proper interface. The FMC
supports 8-bit, 16-bit, and 32-bit read operations from the program flash memory. A write
operation to program flash memory results in a bus error.
In addition, the FMC provides two separate mechanisms for accelerating the interface
between bus masters and program flash memory. A 32-bit speculation buffer can prefetch
the next 32-bit flash memory location, and a 4-way, 4-set program flash memory cache
can store previously accessed program flash memory data for quick access times.

26.1.2 Features
The FMC's features include:
• Interface between bus masters and the 32-bit program flash memory:
• 8-bit, 16-bit, and 32-bit read operations to nonvolatile flash memory.
• Acceleration of data transfer from the program flash memory to the device:

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Modes of operation

• 32-bit prefetch speculation buffer for program flash accesses with controls for
instruction/data access
• 4-way, 4-set, 32-bit line size program flash memory cache for a total of sixteen
32-bit entries with invalidation control

26.2 Modes of operation
The FMC operates only when a bus master accesses the program flash memory. In terms
of chip power modes:
• The FMC operates only in run and wait modes, including VLPR and VLPW modes.
• For any power mode where the program flash memory cannot be accessed, the FMC
is disabled.

26.3 External signal description
The FMC has no external (off-chip) signals.

26.4 Memory map and register descriptions
The MCM's programming model provides control and configuration of the FMC's
features. For details, see the description of the MCM's Platform Control Register
(PLACR).

26.5 Functional description
The FMC is a flash acceleration unit with flexible buffers for user configuration. Besides
managing the interface between bus masters and the program flash memory, the FMC can
be used to customize the program flash memory cache and buffer to provide single-cycle
system clock data access times. Whenever a hit occurs for the prefetch speculation buffer
or the cache (when enabled), the requested data is transferred within a single system
clock.
Upon system reset, the FMC is configured as follows:
• Flash cache is enabled
• Instruction speculation and caching are enabled

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Chapter 26 Flash Memory Controller (FMC)

• Data speculation is disabled
• Data caching is enabled
Though the default configuration provides flash acceleration, advanced users may desire
to customize the FMC buffer configurations to maximize throughput for their use cases.
For example, the user may adjust the controls to enable buffering per access type (data or
instruction).
NOTE
When reconfiguring the FMC, do not program the control and
configuration inputs to the FMC while the program flash
memory is being accessed. Instead, change them with a routine
executing from RAM in supervisor mode.

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Functional description

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Chapter 27
Flash Memory Module (FTFA)
27.1 Introduction
NOTE
For the chip-specific implementation details of this module's
instances see the chip configuration information.
The flash memory module includes the following accessible memory regions:
• Program flash memory for vector space and code store
Flash memory is ideal for single-supply applications, permitting in-the-field erase and
reprogramming operations without the need for any external high voltage power sources.
The flash memory module includes a memory controller that executes commands to
modify flash memory contents. An erased bit reads '1' and a programmed bit reads '0'.
The programming operation is unidirectional; it can only move bits from the '1' state
(erased) to the '0' state (programmed). Only the erase operation restores bits from '0' to
'1'; bits cannot be programmed from a '0' to a '1'.
CAUTION
A flash memory location must be in the erased state before
being programmed. Cumulative programming of bits (back-toback program operations without an intervening erase) within a
flash memory location is not allowed. Re-programming of
existing 0s to 0 is not allowed as this overstresses the device.
The standard shipping condition for flash memory is erased
with security disabled. Data loss over time may occur due to
degradation of the erased ('1') states and/or programmed ('0')
states. Therefore, it is recommended that each flash block or
sector be re-erased immediately prior to factory programming
to ensure that the full data retention capability is achieved.
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Introduction

27.1.1 Features
The flash memory module includes the following features.
NOTE
See the device's Chip Configuration details for the exact
amount of flash memory available on your device.

27.1.1.1 Program Flash Memory Features
• Sector size of 1 Kbyte
• Program flash protection scheme prevents accidental program or erase of stored data
• Automated, built-in, program and erase algorithms with verify

27.1.1.2 Other Flash Memory Module Features
• Internal high-voltage supply generator for flash memory program and erase
operations
• Optional interrupt generation upon flash command completion
• Supports MCU security mechanisms which prevent unauthorized access to the flash
memory contents

27.1.2 Block Diagram
The block diagram of the flash memory module is shown in the following figure.

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Chapter 27 Flash Memory Module (FTFA)

Interrupt

Status
registers

Register access

Memory controller

Program flash
0

Control
registers

To MCU's
flash controller

Figure 27-1. Flash Block Diagram

27.1.3 Glossary
Command write sequence — A series of MCU writes to the flash FCCOB register
group that initiates and controls the execution of flash algorithms that are built into the
flash memory module.
Endurance — The number of times that a flash memory location can be erased and
reprogrammed.
FCCOB (Flash Common Command Object) — A group of flash registers that are used
to pass command, address, data, and any associated parameters to the memory controller
in the flash memory module.
Flash block — A macro within the flash memory module which provides the nonvolatile
memory storage.
Flash Memory Module — All flash blocks plus a flash management unit providing
high-level control and an interface to MCU buses.
IFR — Nonvolatile information register found in each flash block, separate from the
main memory array.
NVM — Nonvolatile memory. A memory technology that maintains stored data during
power-off. The flash array is an NVM using NOR-type flash memory technology.
NVM Normal Mode — An NVM mode that provides basic user access to flash memory
module resources. The CPU or other bus masters initiate flash program and erase
operations (or other flash commands) using writes to the FCCOB register group in the
flash memory module.

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External Signal Description

NVM Special Mode — An NVM mode enabling external, off-chip access to the memory
resources in the flash memory module. A reduced flash command set is available when
the MCU is secured. See the Chip Configuration details for information on when this
mode is used.
Longword — 32 bits of data with an aligned longword having byte-address[1:0] = 00.
Word — 16 bits of data with an aligned word having byte-address[0] = 0.
Program flash — The program flash memory provides nonvolatile storage for vectors
and code store.
Program flash Sector — The smallest portion of the program flash memory
(consecutive addresses) that can be erased.
Retention — The length of time that data can be kept in the NVM without experiencing
errors upon readout. Since erased (1) states are subject to degradation just like
programmed (0) states, the data retention limit may be reached from the last erase
operation (not from the programming time).
RWW— Read-While-Write. The ability to simultaneously read from one memory
resource while commanded operations are active in another memory resource.
Secure — An MCU state conveyed to the flash memory module as described in the Chip
Configuration details for this device. In the secure state, reading and changing NVM
contents is restricted.

27.2 External Signal Description
The flash memory module contains no signals that connect off-chip.

27.3 Memory Map and Registers
This section describes the memory map and registers for the flash memory module. Data
read from unimplemented memory space in the flash memory module is undefined.
Writes to unimplemented or reserved memory space (registers) in the flash memory
module are ignored.

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27.3.1 Flash Configuration Field Description
The program flash memory contains a 16-byte flash configuration field that stores default
protection settings (loaded on reset) and security information that allows the MCU to
restrict access to the flash memory module.
Flash Configuration Field Byte
Address

Size (Bytes)

Field Description

0x0_0400 - 0x0_0407

8

Backdoor Comparison Key. Refer to
Verify Backdoor Access Key Command
and Unsecuring the Chip Using
Backdoor Key Access.

0x0_0408 - 0x0_040B

4

Program flash protection bytes. Refer to
the description of the Program Flash
Protection Registers (FPROT0-3).

0x0_040F

1

Reserved

0x0_040E

1

Reserved

0x0_040D

1

Flash nonvolatile option byte. Refer to
the description of the Flash Option
Register (FOPT).

0x0_040C

1

Flash security byte. Refer to the
description of the Flash Security
Register (FSEC).

27.3.2 Program Flash IFR Map
The program flash IFR is nonvolatile information memory that can be read freely, but the
user has no erase and limited program capabilities (see the Read Once, Program Once,
and Read Resource commands in Read Once Command, Program Once Command and
Read Resource Command). The contents of the program flash IFR are summarized in the
following table and further described in the subsequent paragraphs.
The program flash IFR is located within the program flash 0 memory block.
Address Range

Size (Bytes)

Field Description

0x00 – 0xBF

192

Reserved

0xC0 – 0xFF

64

Program Once Field

27.3.2.1 Program Once Field
The Program Once Field in the program flash IFR provides 64 bytes of user data storage
separate from the program flash main array. The user can program the Program Once
Field one time only as there is no program flash IFR erase mechanism available to the
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Memory Map and Registers

user. The Program Once Field can be read any number of times. This section of the
program flash IFR is accessed in 4-Byte records using the Read Once and Program Once
commands (see Read Once Command and Program Once Command).

27.3.3 Register Descriptions
The flash memory module contains a set of memory-mapped control and status registers.
NOTE
While a command is running (FSTAT[CCIF]=0), register
writes are not accepted to any register except FCNFG and
FSTAT. The no-write rule is relaxed during the start-up reset
sequence, prior to the initial rise of CCIF. During this
initialization period the user may write any register. All register
writes are also disabled (except for registers FCNFG and
FSTAT) whenever an erase suspend request is active
(FCNFG[ERSSUSP]=1).
FTFA memory map
Absolute
address
(hex)

Register name

Width
Access
(in bits)

Reset value

Section/
page

4002_0000

Flash Status Register (FTFA_FSTAT)

8

R/W

00h

27.33.1/425

4002_0001

Flash Configuration Register (FTFA_FCNFG)

8

R/W

00h

27.33.2/426

4002_0002

Flash Security Register (FTFA_FSEC)

8

R

Undefined

27.33.3/428

4002_0003

Flash Option Register (FTFA_FOPT)

8

R

Undefined

27.33.4/429

4002_0004

Flash Common Command Object Registers
(FTFA_FCCOB3)

8

R/W

00h

27.33.5/430

4002_0005

Flash Common Command Object Registers
(FTFA_FCCOB2)

8

R/W

00h

27.33.5/430

4002_0006

Flash Common Command Object Registers
(FTFA_FCCOB1)

8

R/W

00h

27.33.5/430

4002_0007

Flash Common Command Object Registers
(FTFA_FCCOB0)

8

R/W

00h

27.33.5/430

4002_0008

Flash Common Command Object Registers
(FTFA_FCCOB7)

8

R/W

00h

27.33.5/430

4002_0009

Flash Common Command Object Registers
(FTFA_FCCOB6)

8

R/W

00h

27.33.5/430

4002_000A

Flash Common Command Object Registers
(FTFA_FCCOB5)

8

R/W

00h

27.33.5/430

4002_000B

Flash Common Command Object Registers
(FTFA_FCCOB4)

8

R/W

00h

27.33.5/430

4002_000C

Flash Common Command Object Registers
(FTFA_FCCOBB)

8

R/W

00h

27.33.5/430

Table continues on the next page...

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FTFA memory map (continued)
Absolute
address
(hex)

Width
Access
(in bits)

Register name

Reset value

Section/
page

4002_000D

Flash Common Command Object Registers
(FTFA_FCCOBA)

8

R/W

00h

27.33.5/430

4002_000E

Flash Common Command Object Registers
(FTFA_FCCOB9)

8

R/W

00h

27.33.5/430

4002_000F

Flash Common Command Object Registers
(FTFA_FCCOB8)

8

R/W

00h

27.33.5/430

4002_0010

Program Flash Protection Registers (FTFA_FPROT3)

8

R/W

Undefined

27.33.6/431

4002_0011

Program Flash Protection Registers (FTFA_FPROT2)

8

R/W

Undefined

27.33.6/431

4002_0012

Program Flash Protection Registers (FTFA_FPROT1)

8

R/W

Undefined

27.33.6/431

4002_0013

Program Flash Protection Registers (FTFA_FPROT0)

8

R/W

Undefined

27.33.6/431

27.33.1 Flash Status Register (FTFA_FSTAT)
The FSTAT register reports the operational status of the flash memory module.
The CCIF, RDCOLERR, ACCERR, and FPVIOL bits are readable and writable. The
MGSTAT0 bit is read only. The unassigned bits read 0 and are not writable.
NOTE
When set, the Access Error (ACCERR) and Flash Protection
Violation (FPVIOL) bits in this register prevent the launch of
any more commands until the flag is cleared (by writing a one
to it).
Address: 4002_0000h base + 0h offset = 4002_0000h
Bit

7

6

5

4

3

Read

CCIF

RDCOLERR

ACCERR

FPVIOL

Write

w1c

w1c

w1c

w1c

Reset

0

0

0

0

2

1

0

0

0

0

MGSTAT0

0

0

FTFA_FSTAT field descriptions
Field
7
CCIF

Description
Command Complete Interrupt Flag
The CCIF flag indicates that a flash command has completed. The CCIF flag is cleared by writing a 1 to
CCIF to launch a command, and CCIF stays low until command completion or command violation.
The CCIF bit is reset to 0 but is set to 1 by the memory controller at the end of the reset initialization
sequence. Depending on how quickly the read occurs after reset release, the user may or may not see the
0 hardware reset value.
Table continues on the next page...

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FTFA_FSTAT field descriptions (continued)
Field

Description
0
1

6
RDCOLERR

Flash Read Collision Error Flag
The RDCOLERR error bit indicates that the MCU attempted a read from a flash memory resource that
was being manipulated by a flash command (CCIF=0). Any simultaneous access is detected as a collision
error by the block arbitration logic. The read data in this case cannot be guaranteed. The RDCOLERR bit
is cleared by writing a 1 to it. Writing a 0 to RDCOLERR has no effect.
0
1

5
ACCERR

No collision error detected
Collision error detected

Flash Access Error Flag
The ACCERR error bit indicates an illegal access has occurred to a flash memory resource caused by a
violation of the command write sequence or issuing an illegal flash command. While ACCERR is set, the
CCIF flag cannot be cleared to launch a command. The ACCERR bit is cleared by writing a 1 to it. Writing
a 0 to the ACCERR bit has no effect.
0
1

4
FPVIOL

Flash command in progress
Flash command has completed

No access error detected
Access error detected

Flash Protection Violation Flag
The FPVIOL error bit indicates an attempt was made to program or erase an address in a protected area
of program flash memory during a command write sequence . While FPVIOL is set, the CCIF flag cannot
be cleared to launch a command. The FPVIOL bit is cleared by writing a 1 to it. Writing a 0 to the FPVIOL
bit has no effect.
0
1

No protection violation detected
Protection violation detected

3–1
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

0
MGSTAT0

Memory Controller Command Completion Status Flag
The MGSTAT0 status flag is set if an error is detected during execution of a flash command or during the
flash reset sequence. As a status flag, this bit cannot (and need not) be cleared by the user like the other
error flags in this register.
The value of the MGSTAT0 bit for "command-N" is valid only at the end of the "command-N" execution
when CCIF=1 and before the next command has been launched. At some point during the execution of
"command-N+1," the previous result is discarded and any previous error is cleared.

27.33.2 Flash Configuration Register (FTFA_FCNFG)
This register provides information on the current functional state of the flash memory
module.
The erase control bits (ERSAREQ and ERSSUSP) have write restrictions. The
unassigned bits read as noted and are not writable.

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Address: 4002_0000h base + 1h offset = 4002_0001h
Bit

Read
Write
Reset

7

6

5

CCIE

RDCOLLIE

0

0

ERSAREQ

0

4

3

ERSSUSP
0

2

0

0

1

0

0

0

0

0

FTFA_FCNFG field descriptions
Field
7
CCIE

Description
Command Complete Interrupt Enable
The CCIE bit controls interrupt generation when a flash command completes.
0
1

6
RDCOLLIE

Read Collision Error Interrupt Enable
The RDCOLLIE bit controls interrupt generation when a flash memory read collision error occurs.
0
1

5
ERSAREQ

Command complete interrupt disabled
Command complete interrupt enabled. An interrupt request is generated whenever the FSTAT[CCIF]
flag is set.

Read collision error interrupt disabled
Read collision error interrupt enabled. An interrupt request is generated whenever a flash memory
read collision error is detected (see the description of FSTAT[RDCOLERR]).

Erase All Request
This bit issues a request to the memory controller to execute the Erase All Blocks command and release
security. ERSAREQ is not directly writable but is under indirect user control. Refer to the device's Chip
Configuration details on how to request this command.
The ERSAREQ bit sets when an erase all request is triggered external to the flash memory module and
CCIF is set (no command is currently being executed). ERSAREQ is cleared by the flash memory module
when the operation completes.
0
1

4
ERSSUSP

No request or request complete
Request to:
1. run the Erase All Blocks command,
2. verify the erased state,
3. program the security byte in the Flash Configuration Field to the unsecure state, and
4. release MCU security by setting the FSEC[SEC] field to the unsecure state.

Erase Suspend
The ERSSUSP bit allows the user to suspend (interrupt) the Erase Flash Sector command while it is
executing.
0
1

No suspend requested
Suspend the current Erase Flash Sector command execution.

3
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

2–0
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

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27.33.3 Flash Security Register (FTFA_FSEC)
This read-only register holds all bits associated with the security of the MCU and flash
memory module.
During the reset sequence, the register is loaded with the contents of the flash security
byte in the Flash Configuration Field located in program flash memory. The flash basis
for the values is signified by X in the reset value.
Address: 4002_0000h base + 2h offset = 4002_0002h
Bit

7

Read

6

5

KEYEN

4

3

MEEN

2

1

FSLACC

0

SEC

Write
Reset

x*

x*

x*

x*

x*

x*

x*

x*

* Notes:
• x = Undefined at reset.

FTFA_FSEC field descriptions
Field
7–6
KEYEN

Description
Backdoor Key Security Enable
These bits enable and disable backdoor key access to the flash memory module.
00
01
10
11

5–4
MEEN

Mass Erase Enable Bits
Enables and disables mass erase capability of the flash memory module. The state of the MEEN bits is
only relevant when the SEC bits are set to secure outside of NVM Normal Mode. When the SEC field is
set to unsecure, the MEEN setting does not matter.
00
01
10
11

3–2
FSLACC

Backdoor key access disabled
Backdoor key access disabled (preferred KEYEN state to disable backdoor key access)
Backdoor key access enabled
Backdoor key access disabled

Mass erase is enabled
Mass erase is enabled
Mass erase is disabled
Mass erase is enabled

Freescale Failure Analysis Access Code
These bits enable or disable access to the flash memory contents during returned part failure analysis at
Freescale. When SEC is secure and FSLACC is denied, access to the program flash contents is denied
and any failure analysis performed by Freescale factory test must begin with a full erase to unsecure the
part.
When access is granted (SEC is unsecure, or SEC is secure and FSLACC is granted), Freescale factory
testing has visibility of the current flash contents. The state of the FSLACC bits is only relevant when the
SEC bits are set to secure. When the SEC field is set to unsecure, the FSLACC setting does not matter.
Table continues on the next page...

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FTFA_FSEC field descriptions (continued)
Field

Description
00
01
10
11

1–0
SEC

Freescale factory access granted
Freescale factory access denied
Freescale factory access denied
Freescale factory access granted

Flash Security
These bits define the security state of the MCU. In the secure state, the MCU limits access to flash
memory module resources. The limitations are defined per device and are detailed in the Chip
Configuration details. If the flash memory module is unsecured using backdoor key access, the SEC bits
are forced to 10b.
00
01
10
11

MCU security status is secure
MCU security status is secure
MCU security status is unsecure (The standard shipping condition of the flash memory module is
unsecure.)
MCU security status is secure

27.33.4 Flash Option Register (FTFA_FOPT)
The flash option register allows the MCU to customize its operations by examining the
state of these read-only bits, which are loaded from NVM at reset. The function of the
bits is defined in the device's Chip Configuration details.
All bits in the register are read-only .
During the reset sequence, the register is loaded from the flash nonvolatile option byte in
the Flash Configuration Field located in program flash memory. The flash basis for the
values is signified by X in the reset value.
Address: 4002_0000h base + 3h offset = 4002_0003h
Bit

7

6

5

4

Read

3

2

1

0

x*

x*

x*

x*

OPT

Write
Reset

x*

x*

x*

x*

* Notes:
• x = Undefined at reset.

FTFA_FOPT field descriptions
Field
7–0
OPT

Description
Nonvolatile Option
These bits are loaded from flash to this register at reset. Refer to the device's Chip Configuration details
for the definition and use of these bits.

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27.33.5 Flash Common Command Object Registers
(FTFA_FCCOBn)
The FCCOB register group provides 12 bytes for command codes and parameters. The
individual bytes within the set append a 0-B hex identifier to the FCCOB register name:
FCCOB0, FCCOB1, ..., FCCOBB.
Address: 4002_0000h base + 4h offset + (1d × i), where i=0d to 11d
Bit

Read
Write
Reset

7

6

5

4

3

2

1

0

0

0

0

0

CCOBn
0

0

0

0

FTFA_FCCOBn field descriptions
Field

Description

7–0
CCOBn

The FCCOB register provides a command code and relevant parameters to the memory controller. The
individual registers that compose the FCCOB data set can be written in any order, but you must provide all
needed values, which vary from command to command. First, set up all required FCCOB fields and then
initiate the command’s execution by writing a 1 to the FSTAT[CCIF] bit. This clears the CCIF bit, which
locks all FCCOB parameter fields and they cannot be changed by the user until the command completes
(CCIF returns to 1). No command buffering or queueing is provided; the next command can be loaded
only after the current command completes.
Some commands return information to the FCCOB registers. Any values returned to FCCOB are available
for reading after the FSTAT[CCIF] flag returns to 1 by the memory controller.
The following table shows a generic flash command format. The first FCCOB register, FCCOB0, always
contains the command code. This 8-bit value defines the command to be executed. The command code is
followed by the parameters required for this specific flash command, typically an address and/or data
values.
NOTE: The command parameter table is written in terms of FCCOB Number (which is equivalent to the
byte number). This number is a reference to the FCCOB register name and is not the register
address.
FCCOB Number

Typical Command Parameter Contents [7:0]

0

FCMD (a code that defines the flash command)

1

Flash address [23:16]

2

Flash address [15:8]

3

Flash address [7:0]

4

Data Byte 0

5

Data Byte 1

6

Data Byte 2

7

Data Byte 3

8

Data Byte 4

9

Data Byte 5

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FTFA_FCCOBn field descriptions (continued)
Field

Description
FCCOB Number

Typical Command Parameter Contents [7:0]

A

Data Byte 6

B

Data Byte 7

FCCOB Endianness and Multi-Byte Access :
The FCCOB register group uses a big endian addressing convention. For all command parameter fields
larger than 1 byte, the most significant data resides in the lowest FCCOB register number. The FCCOB
register group may be read and written as individual bytes, aligned words (2 bytes) or aligned longwords
(4 bytes).

27.33.6 Program Flash Protection Registers (FTFA_FPROTn)
The FPROT registers define which logical program flash regions are protected from
program and erase operations. Protected flash regions cannot have their content changed;
that is, these regions cannot be programmed and cannot be erased by any flash command.
Unprotected regions can be changed by program and erase operations.
The four FPROT registers allow up to 32 protectable regions. Each bit protects a 1/32
region of the program flash memory except for memory configurations with less than 32
Kbytes of program flash where each assigned bit protects 1 Kbyte . For configurations
with 24 Kbytes of program flash memory or less, FPROT0 is not used. For configurations
with 16 Kbytes of program flash memory or less, FPROT1 is not used. For configurations
with 8 Kbytes of program flash memory, FPROT2 is not used. The bitfields are defined
in each register as follows:
Program flash protection register

Program flash protection bits

FPROT0

PROT[31:24]

FPROT1

PROT[23:16]

FPROT2

PROT[15:8]

FPROT3

PROT[7:0]

During the reset sequence, the FPROT registers are loaded with the contents of the
program flash protection bytes in the Flash Configuration Field as indicated in the
following table.
Program flash protection register

Flash Configuration Field offset address

FPROT0

0x000B

FPROT1

0x000A
Table continues on the next page...

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Functional Description

Program flash protection register

Flash Configuration Field offset address

FPROT2

0x0009

FPROT3

0x0008

To change the program flash protection that is loaded during the reset sequence,
unprotect the sector of program flash memory that contains the Flash Configuration
Field. Then, reprogram the program flash protection byte.
Address: 4002_0000h base + 10h offset + (1d × i), where i=0d to 3d
Bit

Read
Write
Reset

7

6

5

4

3

2

1

0

x*

x*

x*

x*

PROT
x*

x*

x*

x*

* Notes:
• x = Undefined at reset.

FTFA_FPROTn field descriptions
Field
7–0
PROT

Description
Program Flash Region Protect
Each program flash region can be protected from program and erase operations by setting the associated
PROT bit.
In NVM Normal mode: The protection can only be increased, meaning that currently unprotected memory
can be protected, but currently protected memory cannot be unprotected. Since unprotected regions are
marked with a 1 and protected regions use a 0, only writes changing 1s to 0s are accepted. This 1-to-0
transition check is performed on a bit-by-bit basis. Those FPROT bits with 1-to-0 transitions are accepted
while all bits with 0-to-1 transitions are ignored.
In NVM Special mode: All bits of FPROT are writable without restriction. Unprotected areas can be
protected and protected areas can be unprotected.
Restriction: The user must never write to any FPROT register while a command is running (CCIF=0).
Trying to alter data in any protected area in the program flash memory results in a protection violation
error and sets the FSTAT[FPVIOL] bit. A full block erase of a program flash block is not possible if it
contains any protected region.
Each bit in the 32-bit protection register represents 1/32 of the total program flash except for
configurations where program flash memory is less than 32 Kbytes. For configurations with less than 32
Kbytes of program flash memory, each assigned bit represents 1 Kbyte.
0
1

Program flash region is protected.
Program flash region is not protected

27.4 Functional Description
The following sections describe functional details of the flash memory module.

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27.4.1 Flash Protection
Individual regions within the flash memory can be protected from program and erase
operations. Protection is controlled by the following registers:
• FPROTn — Four registers that protect 32 regions of the program flash memory as
shown in the following figure
Program flash
0x0_0000

Last program flash address

Program flash size / 32

FPROT3[PROT0]

Program flash size / 32

FPROT3[PROT1]

Program flash size / 32

FPROT3[PROT2]

Program flash size / 32

FPROT3[PROT3]

Program flash size / 32

FPROT0[PROT29]

Program flash size / 32

FPROT0[PROT30]

Program flash size / 32

FPROT0[PROT31]

Figure 27-24. Program flash protection

27.4.2 Interrupts
The flash memory module can generate interrupt requests to the MCU upon the
occurrence of various flash events. These interrupt events and their associated status and
control bits are shown in the following table.
Table 27-24. Flash Interrupt Sources
Flash Event

Readable

Interrupt

Status Bit

Enable Bit

Flash Command Complete

FSTAT[CCIF]

FCNFG[CCIE]

Flash Read Collision Error

FSTAT[RDCOLERR]

FCNFG[RDCOLLIE]

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Functional Description

Note
Vector addresses and their relative interrupt priority are
determined at the MCU level.
Some devices also generate a bus error response as a result of a Read Collision Error
event. See the chip configuration information to determine if a bus error response is also
supported.

27.4.3 Flash Operation in Low-Power Modes

27.4.3.1 Wait Mode
When the MCU enters wait mode, the flash memory module is not affected. The flash
memory module can recover the MCU from wait via the command complete interrupt
(see Interrupts).

27.4.3.2 Stop Mode
When the MCU requests stop mode, if a flash command is active (CCIF = 0) the
command execution completes before the MCU is allowed to enter stop mode.
CAUTION
The MCU should never enter stop mode while any flash
command is running (CCIF = 0).
NOTE
While the MCU is in very-low-power modes (VLPR, VLPW,
VLPS), the flash memory module does not accept flash
commands.

27.4.4 Functional Modes of Operation
The flash memory module has two operating modes: NVM Normal and NVM Special.
The operating mode affects the command set availability (see Table 27-25). Refer to the
Chip Configuration details of this device for how to activate each mode.

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27.4.5 Flash Reads and Ignored Writes
The flash memory module requires only the flash address to execute a flash memory
read.
The MCU must not read from the flash memory while commands are running (as
evidenced by CCIF=0) on that block. Read data cannot be guaranteed from a flash block
while any command is processing within that block. The block arbitration logic detects
any simultaneous access and reports this as a read collision error (see the
FSTAT[RDCOLERR] bit).

27.4.6 Read While Write (RWW)
The following simultaneous accesses are not allowed:
• Reading from program flash memory space while a flash command is active
(CCIF=0).

27.4.7 Flash Program and Erase
All flash functions except read require the user to setup and launch a flash command
through a series of peripheral bus writes. The user cannot initiate any further flash
commands until notified that the current command has completed. The flash command
structure and operation are detailed in Flash Command Operations.

27.4.8 Flash Command Operations
Flash command operations are typically used to modify flash memory contents. The next
sections describe:
• The command write sequence used to set flash command parameters and launch
execution
• A description of all flash commands available

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Functional Description

27.4.8.1 Command Write Sequence
Flash commands are specified using a command write sequence illustrated in Figure
27-25. The flash memory module performs various checks on the command (FCCOB)
content and continues with command execution if all requirements are fulfilled.
Before launching a command, the ACCERR and FPVIOL bits in the FSTAT register
must be zero and the CCIF flag must read 1 to verify that any previous command has
completed. If CCIF is zero, the previous command execution is still active, a new
command write sequence cannot be started, and all writes to the FCCOB registers are
ignored.
27.4.8.1.1

Load the FCCOB Registers

The user must load the FCCOB registers with all parameters required by the desired flash
command. The individual registers that make up the FCCOB data set can be written in
any order.
27.4.8.1.2

Launch the Command by Clearing CCIF

Once all relevant command parameters have been loaded, the user launches the command
by clearing the FSTAT[CCIF] bit by writing a '1' to it. The CCIF flag remains zero until
the flash command completes.
The FSTAT register contains a blocking mechanism that prevents a new command from
launching (can't clear CCIF) if the previous command resulted in an access error
(FSTAT[ACCERR]=1) or a protection violation (FSTAT[FPVIOL]=1). In error
scenarios, two writes to FSTAT are required to initiate the next command: the first write
clears the error flags, the second write clears CCIF.
27.4.8.1.3

Command Execution and Error Reporting

The command processing has several steps:
1. The flash memory module reads the command code and performs a series of
parameter checks and protection checks, if applicable, which are unique to each
command.
If the parameter check fails, the FSTAT[ACCERR] (access error) flag is set.
ACCERR reports invalid instruction codes and out-of bounds addresses. Usually,
access errors suggest that the command was not set-up with valid parameters in the
FCCOB register group.

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Program and erase commands also check the address to determine if the operation is
requested to execute on protected areas. If the protection check fails, the
FSTAT[FPVIOL] (protection error) flag is set.
Command processing never proceeds to execution when the parameter or protection
step fails. Instead, command processing is terminated after setting the FSTAT[CCIF]
bit.
2. If the parameter and protection checks pass, the command proceeds to execution.
Run-time errors, such as failure to erase verify, may occur during the execution
phase. Run-time errors are reported in the FSTAT[MGSTAT0] bit. A command may
have access errors, protection errors, and run-time errors, but the run-time errors are
not seen until all access and protection errors have been corrected.
3. Command execution results, if applicable, are reported back to the user via the
FCCOB and FSTAT registers.
4. The flash memory module sets the FSTAT[CCIF] bit signifying that the command
has completed.
The flow for a generic command write sequence is illustrated in the following figure.

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Functional Description
START

Read: FSTAT register

FCCOB
Availability Check

no

CCIF
= ‘1’?

Previous command complete?
yes

Access Error and
Protection Violation
Check

Results from previous command
yes

ACCERR/
FPVIOL
Set?

Clear the old errors
Write 0x30 to FSTAT register

no
Write to the FCCOB registers
to load the required command parameter.

More
Parameters?

yes

no
Clear the CCIF to launch the command
Write 0x80 to FSTAT register

EXIT

Figure 27-25. Generic Flash Command Write Sequence Flowchart

27.4.8.2 Flash Commands
The following table summarizes the function of all flash commands.
FCMD

Command

Program flash

Function

0x01

Read 1s Section

×

Verify that a given number of
program flash locations from
a starting address are
erased.

0x02

Program Check

×

Tests previously-programmed
locations at margin read
levels.

0x03

Read Resource

IFR, ID

Read 4 bytes from program
flash IFR or version ID.

0x06

Program Longword

×

Program 4 bytes in a program
flash block.

Table continues on the next page...

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FCMD

Command

Program flash

Function

0x09

Erase Flash Sector

×

Erase all bytes in a program
flash sector.

0x40

Read 1s All Blocks

×

Verify that the program flash
block is erased then release
MCU security.

0x41

Read Once

IFR

Read 4 bytes of a dedicated
64 byte field in the program
flash 0 IFR.

0x43

Program Once

IFR

One-time program of 4 bytes
of a dedicated 64-byte field in
the program flash 0 IFR.

0x44

Erase All Blocks

×

Erase the program flash
block, verify-erase and
release MCU security.
NOTE:

0x45

Verify Backdoor Access Key

×

An erase is only
possible when all
memory locations
are unprotected.

Release MCU security after
comparing a set of usersupplied security keys to
those stored in the program
flash.

27.4.8.3 Flash Commands by Mode
The following table shows the flash commands that can be executed in each flash
operating mode.
Table 27-25. Flash Commands by Mode
FCMD

Command

0x01

NVM Normal

NVM Special

Unsecure

Secure

MEEN=10

Unsecure

Secure

MEEN=10

Read 1s Section

×

×

×

×

—

—

0x02

Program Check

×

×

×

×

—

—

0x03

Read Resource

×

×

×

×

—

—

0x06

Program Longword

×

×

×

×

—

—

0x09

Erase Flash Sector

×

×

×

×

—

—

0x40

Read 1s All Blocks

×

×

×

×

×

—

0x41

Read Once

×

×

×

×

—

—

0x43

Program Once

×

×

×

×

—

—

0x44

Erase All Blocks

×

×

×

×

×

—

0x45

Verify Backdoor Access
Key

×

×

×

×

—

—

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Functional Description

27.4.9 Margin Read Commands
The Read-1s commands (Read 1s All Blocks and Read 1s Section) and the Program
Check command have a margin choice parameter that allows the user to apply nonstandard read reference levels to the program flash array reads performed by these
commands. Using the preset 'user' and 'factory' margin levels, these commands perform
their associated read operations at tighter tolerances than a 'normal' read. These nonstandard read levels are applied only during the command execution. All simple
(uncommanded) flash array reads to the MCU always use the standard, un-margined, read
reference level.
Only the 'normal' read level should be employed during normal flash usage. The nonstandard, 'user' and 'factory' margin levels should be employed only in special cases.
They can be used during special diagnostic routines to gain confidence that the device is
not suffering from the end-of-life data loss customary of flash memory devices.
Erased ('1') and programmed ('0') bit states can degrade due to elapsed time and data
cycling (number of times a bit is erased and re-programmed). The lifetime of the erased
states is relative to the last erase operation. The lifetime of the programmed states is
measured from the last program time.
The 'user' and 'factory' levels become, in effect, a minimum safety margin; i.e. if the reads
pass at the tighter tolerances of the 'user' and 'factory' margins, then the 'normal' reads
have at least this much safety margin before they experience data loss.
The 'user' margin is a small delta to the normal read reference level. 'User' margin levels
can be employed to check that flash memory contents have adequate margin for normal
level read operations. If unexpected read results are encountered when checking flash
memory contents at the 'user' margin levels, loss of information might soon occur during
'normal' readout.
The 'factory' margin is a bigger deviation from the norm, a more stringent read criteria
that should only be attempted immediately (or very soon) after completion of an erase or
program command, early in the cycling life. 'Factory' margin levels can be used to check
that flash memory contents have adequate margin for long-term data retention at the
normal level setting. If unexpected results are encountered when checking flash memory
contents at 'factory' margin levels, the flash memory contents should be erased and
reprogrammed.
CAUTION
Factory margin levels must only be used during verify of the
initial factory programming.
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27.4.10 Flash Command Description
This section describes all flash commands that can be launched by a command write
sequence. The flash memory module sets the FSTAT[ACCERR] bit and aborts the
command execution if any of the following illegal conditions occur:
• There is an unrecognized command code in the FCCOB FCMD field.
• There is an error in a FCCOB field for the specific commands. Refer to the error
handling table provided for each command.
Ensure that the ACCERR and FPVIOL bits in the FSTAT register are cleared prior to
starting the command write sequence. As described in Launch the Command by Clearing
CCIF, a new command cannot be launched while these error flags are set.
Do not attempt to read a flash block while the flash memory module is running a
command (CCIF = 0) on that same block. The flash memory module may return invalid
data to the MCU with the collision error flag (FSTAT[RDCOLERR]) set.
CAUTION
Flash data must be in the erased state before being
programmed. Cumulative programming of bits (adding more
zeros) is not allowed.

27.4.10.1 Read 1s Section Command
The Read 1s Section command checks if a section of program flash memory is erased to
the specified read margin level. The Read 1s Section command defines the starting
address and the number of longwords to be verified.
Table 27-26. Read 1s Section Command FCCOB Requirements
FCCOB Number

FCCOB Contents [7:0]

0

0x01 (RD1SEC)

1

Flash address [23:16] of the first longword to be verified

2

Flash address [15:8] of the first longword to be verified

3

Flash address [7:0]1 of the first longword to be verified

4

Number of longwords to be verified [15:8]

5

Number of longwords to be verified [7:0]

6

Read-1 Margin Choice

1. Must be longword aligned (Flash address [1:0] = 00).

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Functional Description

Upon clearing CCIF to launch the Read 1s Section command, the flash memory module
sets the read margin for 1s according to Table 27-27 and then reads all locations within
the specified section of flash memory. If the flash memory module fails to read all 1s (i.e.
the flash section is not erased), the FSTAT[MGSTAT0] bit is set. The CCIF flag sets
after the Read 1s Section operation completes.
Table 27-27. Margin Level Choices for Read 1s Section
Read Margin Choice

Margin Level Description

0x00

Use the 'normal' read level for 1s

0x01

Apply the 'User' margin to the normal read-1 level

0x02

Apply the 'Factory' margin to the normal read-1 level

Table 27-28. Read 1s Section Command Error Handling
Error Condition

Error Bit

Command not available in current mode/security

FSTAT[ACCERR]

An invalid margin code is supplied

FSTAT[ACCERR]

An invalid flash address is supplied

FSTAT[ACCERR]

Flash address is not longword aligned

FSTAT[ACCERR]

The requested section crosses a Flash block boundary

FSTAT[ACCERR]

The requested number of longwords is zero

FSTAT[ACCERR]

Read-1s fails

FSTAT[MGSTAT0]

27.4.10.2 Program Check Command
The Program Check command tests a previously programmed program flash longword to
see if it reads correctly at the specified margin level.
Table 27-29. Program Check Command FCCOB Requirements
FCCOB Number

FCCOB Contents [7:0]

0

0x02 (PGMCHK)

1

Flash address [23:16]

2

Flash address [15:8]

3

Flash address [7:0]1

4

Margin Choice

8

Byte 0 expected data

9

Byte 1 expected data

A

Byte 2 expected data

B

Byte 3 expected data

1. Must be longword aligned (Flash address [1:0] = 00).

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Upon clearing CCIF to launch the Program Check command, the flash memory module
sets the read margin for 1s according to Table 27-30, reads the specified longword, and
compares the actual read data to the expected data provided by the FCCOB. If the
comparison at margin-1 fails, the FSTAT[MGSTAT0] bit is set.
The flash memory module then sets the read margin for 0s, re-reads, and compares again.
If the comparison at margin-0 fails, the FSTAT[MGSTAT0] bit is set. The CCIF flag is
set after the Program Check operation completes.
The supplied address must be longword aligned (the lowest two bits of the byte address
must be 00):
• Byte 3 data is written to the supplied byte address ('start'),
• Byte 2 data is programmed to byte address start+0b01,
• Byte 1 data is programmed to byte address start+0b10,
• Byte 0 data is programmed to byte address start+0b11.
NOTE
See the description of margin reads, Margin Read Commands
Table 27-30. Margin Level Choices for Program Check
Read Margin Choice

Margin Level Description

0x01

Read at 'User' margin-1 and 'User' margin-0

0x02

Read at 'Factory' margin-1 and 'Factory' margin-0

Table 27-31. Program Check Command Error Handling
Error Condition

Error Bit

Command not available in current mode/security

FSTAT[ACCERR]

An invalid flash address is supplied

FSTAT[ACCERR]

Flash address is not longword aligned

FSTAT[ACCERR]

An invalid margin choice is supplied

FSTAT[ACCERR]

Either of the margin reads does not match the expected data

FSTAT[MGSTAT0]

27.4.10.3 Read Resource Command
The Read Resource command allows the user to read data from special-purpose memory
resources located within the flash memory module. The special-purpose memory
resources available include program flash IFR space and the Version ID field. Each
resource is assigned a select code as shown in Table 27-33.

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Functional Description

Table 27-32. Read Resource Command FCCOB Requirements
FCCOB Number

FCCOB Contents [7:0]

0

0x03 (RDRSRC)

1

Flash address [23:16]

2

Flash address [15:8]

3

Flash address [7:0]1
Returned Values

4

Read Data [31:24]

5

Read Data [23:16]

6

Read Data [15:8]

7

Read Data [7:0]
User-provided values

8

Resource Select Code (see Table 27-33)

1. Must be longword aligned (Flash address [1:0] = 00).

Table 27-33. Read Resource Select Codes
Resource
Select Code

Description

Resource Size

Local Address Range

0x00

Program Flash 0 IFR

256 Bytes

0x00_0000 - 0x00_00FF

0x011

Version ID

8 Bytes

0x00_0000 - 0x00_0007

1. Located in program flash 0 reserved space.

After clearing CCIF to launch the Read Resource command, four consecutive bytes are
read from the selected resource at the provided relative address and stored in the FCCOB
register. The CCIF flag sets after the Read Resource operation completes. The Read
Resource command exits with an access error if an invalid resource code is provided or if
the address for the applicable area is out-of-range.
Table 27-34. Read Resource Command Error Handling
Error Condition

Error Bit

Command not available in current mode/security

FSTAT[ACCERR]

An invalid resource code is entered

FSTAT[ACCERR]

Flash address is out-of-range for the targeted resource.

FSTAT[ACCERR]

Flash address is not longword aligned

FSTAT[ACCERR]

27.4.10.4 Program Longword Command
The Program Longword command programs four previously-erased bytes in the program
flash memory using an embedded algorithm.
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Chapter 27 Flash Memory Module (FTFA)

CAUTION
A flash memory location must be in the erased state before
being programmed. Cumulative programming of bits (back-toback program operations without an intervening erase) within a
flash memory location is not allowed. Re-programming of
existing 0s to 0 is not allowed as this overstresses the device.
Table 27-35. Program Longword Command FCCOB Requirements
FCCOB Number

FCCOB Contents [7:0]

0

0x06 (PGM4)

1

Flash address [23:16]

2

Flash address [15:8]

3

Flash address [7:0]1

4

Byte 0 program value

5

Byte 1 program value

6

Byte 2 program value

7

Byte 3 program value

1. Must be longword aligned (Flash address [1:0] = 00).

Upon clearing CCIF to launch the Program Longword command, the flash memory
module programs the data bytes into the flash using the supplied address. The targeted
flash locations must be currently unprotected (see the description of the FPROT registers)
to permit execution of the Program Longword operation.
The programming operation is unidirectional. It can only move NVM bits from the erased
state ('1') to the programmed state ('0'). Erased bits that fail to program to the '0' state are
flagged as errors in FSTAT[MGSTAT0]. The CCIF flag is set after the Program
Longword operation completes.
The supplied address must be longword aligned (flash address [1:0] = 00):
•
•
•
•

Byte 3 data is written to the supplied byte address ('start'),
Byte 2 data is programmed to byte address start+0b01,
Byte 1 data is programmed to byte address start+0b10, and
Byte 0 data is programmed to byte address start+0b11.
Table 27-36. Program Longword Command Error Handling

Error Condition

Error Bit

Command not available in current mode/security

FSTAT[ACCERR]

An invalid flash address is supplied

FSTAT[ACCERR]

Flash address is not longword aligned

FSTAT[ACCERR]

Flash address points to a protected area

FSTAT[FPVIOL]
Table continues on the next page...

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Functional Description

Table 27-36. Program Longword Command Error Handling (continued)
Error Condition

Error Bit

Any errors have been encountered during the verify operation

FSTAT[MGSTAT0]

27.4.10.5 Erase Flash Sector Command
The Erase Flash Sector operation erases all addresses in a flash sector.
Table 27-37. Erase Flash Sector Command FCCOB Requirements
FCCOB Number

FCCOB Contents [7:0]

0

0x09 (ERSSCR)

1

Flash address [23:16] in the flash sector to be erased

2

Flash address [15:8] in the flash sector to be erased

3

Flash address [7:0]1 in the flash sector to be erased

1. Must be longword aligned (flash address [1:0] = 00).

After clearing CCIF to launch the Erase Flash Sector command, the flash memory
module erases the selected program flash sector and then verifies that it is erased. The
Erase Flash Sector command aborts if the selected sector is protected (see the description
of the FPROT registers). If the erase-verify fails the FSTAT[MGSTAT0] bit is set. The
CCIF flag is set after the Erase Flash Sector operation completes. The Erase Flash Sector
command is suspendable (see the FCNFG[ERSSUSP] bit and Figure 27-26).
Table 27-38. Erase Flash Sector Command Error Handling
Error Condition

Error Bit

Command not available in current mode/security

FSTAT[ACCERR]

An invalid Flash address is supplied

FSTAT[ACCERR]

Flash address is not longword aligned

FSTAT[ACCERR]

The selected program flash sector is protected

FSTAT[FPVIOL]

Any errors have been encountered during the verify operation

27.4.10.5.1

FSTAT[MGSTAT0]

Suspending an Erase Flash Sector Operation

To suspend an Erase Flash Sector operation set the FCNFG[ERSSUSP] bit (see Flash
Configuration Field Description) when CCIF is clear and the CCOB command field holds
the code for the Erase Flash Sector command. During the Erase Flash Sector operation
(see Erase Flash Sector Command), the flash memory module samples the state of the
ERSSUSP bit at convenient points. If the flash memory module detects that the
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Chapter 27 Flash Memory Module (FTFA)

ERSSUSP bit is set, the Erase Flash Sector operation is suspended and the flash memory
module sets CCIF. While ERSSUSP is set, all writes to flash registers are ignored except
for writes to the FSTAT and FCNFG registers.
If an Erase Flash Sector operation effectively completes before the flash memory module
detects that a suspend request has been made, the flash memory module clears the
ERSSUSP bit prior to setting CCIF. When an Erase Flash Sector operation has been
successfully suspended, the flash memory module sets CCIF and leaves the ERSSUSP bit
set. While CCIF is set, the ERSSUSP bit can only be cleared to prevent the withdrawal of
a suspend request before the flash memory module has acknowledged it.
27.4.10.5.2

Resuming a Suspended Erase Flash Sector Operation

If the ERSSUSP bit is still set when CCIF is cleared to launch the next command, the
previous Erase Flash Sector operation resumes. The flash memory module acknowledges
the request to resume a suspended operation by clearing the ERSSUSP bit. A new
suspend request can then be made by setting ERSSUSP. A single Erase Flash Sector
operation can be suspended and resumed multiple times.
There is a minimum elapsed time limit between the request to resume the Erase Flash
Sector operation (CCIF is cleared) and the request to suspend the operation again
(ERSSUSP is set). This minimum time period is required to ensure that the Erase Flash
Sector operation will eventually complete. If the minimum period is continually violated,
i.e. the suspend requests come repeatedly and too quickly, no forward progress is made
by the Erase Flash Sector algorithm. The resume/suspend sequence runs indefinitely
without completing the erase.
27.4.10.5.3

Aborting a Suspended Erase Flash Sector Operation

The user may choose to abort a suspended Erase Flash Sector operation by clearing the
ERSSUSP bit prior to clearing CCIF for the next command launch. When a suspended
operation is aborted, the flash memory module starts the new command using the new
FCCOB contents.
Note
Aborting the erase leaves the bitcells in an indeterminate,
partially-erased state. Data in this sector is not reliable until a
new erase command fully completes.
The following figure shows how to suspend and resume the Erase Flash Sector operation.

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Functional Description
Enter with CCIF = 1

Command Initiation
ERSSCR Command
(Write FCCOB)

Memory Controller
Command Processing

Launch/Resume Command
(Clear CCIF)
Yes

SUSPACK=1
Next Command
(Write FCCOB)

Yes

CCIF = 1?
No

No

Interrupt?

Yes
Request Suspend
(Set ERSSUSP)

Start
New

No

Restore Erase Algo
Clear SUSPACK = 0

Execute

Yes

DONE?
No
ERSSUSP=1?

No

CCIF = 1?

Resume
ERSSCR

No

Yes
Save Erase Algo

Clear ERSSUSP

Yes
Service Interrupt
(Read Flash)

ERSSCR Suspended
ERSSUSP=1

ERSSCR
Completed
Yes

ERSSUSP=0?

ERSSCR Suspended
Yes

Set SUSPACK = 1
ERSSCR Completed
ERSSUSP=0

Set CCIF

No

Resume Erase?
No, Abort

ERSSUSP: Bit in FCNFG register
SUSPACK: Internal Suspend Acknowledge

Clear ERSSUSP

User Cmd Interrupt/Suspend

Figure 27-26. Suspend and Resume of Erase Flash Sector Operation

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Chapter 27 Flash Memory Module (FTFA)

27.4.10.6 Read 1s All Blocks Command
The Read 1s All Blocks command checks if the program flash blocks have been erased to
the specified read margin level, if applicable, and releases security if the readout passes,
i.e. all data reads as '1'.
Table 27-39. Read 1s All Blocks Command FCCOB Requirements
FCCOB Number

FCCOB Contents [7:0]

0

0x40 (RD1ALL)

1

Read-1 Margin Choice

After clearing CCIF to launch the Read 1s All Blocks command, the flash memory
module :
• sets the read margin for 1s according to Table 27-40,
• checks the contents of the program flash are in the erased state.
If the flash memory module confirms that these memory resources are erased, security is
released by setting the FSEC[SEC] field to the unsecure state. The security byte in the
flash configuration field (see Flash Configuration Field Description) remains unaffected
by the Read 1s All Blocks command. If the read fails, i.e. all memory resources are not in
the fully erased state, the FSTAT[MGSTAT0] bit is set.
The CCIF flag sets after the Read 1s All Blocks operation has completed.
Table 27-40. Margin Level Choices for Read 1s All Blocks
Read Margin Choice

Margin Level Description

0x00

Use the 'normal' read level for 1s

0x01

Apply the 'User' margin to the normal read-1 level

0x02

Apply the 'Factory' margin to the normal read-1 level

Table 27-41. Read 1s All Blocks Command Error Handling
Error Condition

Error Bit

An invalid margin choice is specified

FSTAT[ACCERR]

Read-1s fails

FSTAT[MGSTAT0]

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Functional Description

27.4.10.7 Read Once Command
The Read Once command provides read access to a reserved 64-byte field located in the
program flash 0 IFR (see Program Flash IFR Map and Program Once Field). Access to
this field is via 16 records, each 4 bytes long. The Read Once field is programmed using
the Program Once command described in Program Once Command.
Table 27-42. Read Once Command FCCOB Requirements
FCCOB Number

FCCOB Contents [7:0]

0

0x41 (RDONCE)

1

Read Once record index (0x00 - 0x0F)

2

Not used

3

Not used
Returned Values

4

Read Once byte 0 value

5

Read Once byte 1 value

6

Read Once byte 2 value

7

Read Once byte 3 value

After clearing CCIF to launch the Read Once command, a 4-byte Read Once record is
read from the program flash IFR and stored in the FCCOB register. The CCIF flag is set
after the Read Once operation completes. Valid record index values for the Read Once
command range from 0x00 to 0x0F. During execution of the Read Once command, any
attempt to read addresses within the program flash block containing this 64-byte field
returns invalid data. The Read Once command can be executed any number of times.
Table 27-43. Read Once Command Error Handling
Error Condition

Error Bit

Command not available in current mode/security

FSTAT[ACCERR]

An invalid record index is supplied

FSTAT[ACCERR]

27.4.10.8 Program Once Command
The Program Once command enables programming to a reserved 64-byte field in the
program flash 0 IFR (see Program Flash IFR Map and Program Once Field). Access to
the Program Once field is via 16 records, each 4 bytes long. The Program Once field can
be read using the Read Once command (see Read Once Command) or using the Read
Resource command (see Read Resource Command). Each Program Once record can be
programmed only once since the program flash 0 IFR cannot be erased.
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Table 27-44. Program Once Command FCCOB Requirements
FCCOB Number

FCCOB Contents [7:0]

0

0x43 (PGMONCE)

1

Program Once record index (0x00 - 0x0F)

2

Not Used

3

Not Used

4

Program Once Byte 0 value

5

Program Once Byte 1 value

6

Program Once Byte 2 value

7

Program Once Byte 3 value

After clearing CCIF to launch the Program Once command, the flash memory module
first verifies that the selected record is erased. If erased, then the selected record is
programmed using the values provided. The Program Once command also verifies that
the programmed values read back correctly. The CCIF flag is set after the Program Once
operation has completed.
The reserved program flash 0 IFR location accessed by the Program Once command
cannot be erased and any attempt to program one of these records when the existing value
is not Fs (erased) is not allowed. Valid record index values for the Program Once
command range from 0x00 to 0x0F. During execution of the Program Once command,
any attempt to read addresses within the program flash block containing this 64-byte field
returns invalid data.
Table 27-45. Program Once Command Error Handling
Error Condition

Error Bit

Command not available in current mode/security

FSTAT[ACCERR]

An invalid record index is supplied
The requested record has already been programmed to a non-FFFF

FSTAT[ACCERR]
value1

Any errors have been encountered during the verify operation

FSTAT[ACCERR]
FSTAT[MGSTAT0]

1. If a Program Once record is initially programmed to 0xFFFF_FFFF, the Program Once command is allowed to execute
again on that same record.

27.4.10.9 Erase All Blocks Command
The Erase All Blocks operation erases all flash memory, verifies all memory contents,
and releases MCU security.

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Table 27-46. Erase All Blocks Command FCCOB Requirements
FCCOB Number

FCCOB Contents [7:0]

0

0x44 (ERSALL)

After clearing CCIF to launch the Erase All Blocks command, the flash memory module
erases all program flash memory, then verifies that all are erased.
If the flash memory module verifies that all flash memories were properly erased,
security is released by setting the FSEC[SEC] field to the unsecure state. The Erase All
Blocks command aborts if any flash region is protected. The security byte and all other
contents of the flash configuration field (see Flash Configuration Field Description) are
erased by the Erase All Blocks command. If the erase-verify fails, the
FSTAT[MGSTAT0] bit is set. The CCIF flag is set after the Erase All Blocks operation
completes.
Table 27-47. Erase All Blocks Command Error Handling
Error Condition

Error Bit

Command not available in current mode/security

FSTAT[ACCERR]

Any region of the program flash memory is protected

FSTAT[FPVIOL]

Any errors have been encountered during the verify operation

27.4.10.9.1

FSTAT[MGSTAT0]

Triggering an Erase All External to the Flash Memory Module

The functionality of the Erase All Blocks command is also available in an uncommanded
fashion outside of the flash memory. Refer to the device's Chip Configuration details for
information on this functionality.
Before invoking the external erase all function, the FSTAT[ACCERR and PVIOL] flags
must be cleared and the FCCOB0 register must not contain 0x44. When invoked, the
erase-all function erases all program flash memory regardless of the protection settings. If
the post-erase verify passes, the routine then releases security by setting the FSEC[SEC]
field register to the unsecure state. The security byte in the Flash Configuration Field is
also programmed to the unsecure state. The status of the erase-all request is reflected in
the FCNFG[ERSAREQ] bit. The FCNFG[ERSAREQ] bit is cleared once the operation
completes and the normal FSTAT error reporting is available as described in Erase All
Blocks Command.

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Chapter 27 Flash Memory Module (FTFA)

27.4.10.10 Verify Backdoor Access Key Command
The Verify Backdoor Access Key command only executes if the mode and security
conditions are satisfied (see Flash Commands by Mode). Execution of the Verify
Backdoor Access Key command is further qualified by the FSEC[KEYEN] bits. The
Verify Backdoor Access Key command releases security if user-supplied keys in the
FCCOB match those stored in the Backdoor Comparison Key bytes of the Flash
Configuration Field (see Flash Configuration Field Description). The column labelled
Flash Configuration Field offset address shows the location of the matching byte in the
Flash Configuration Field.
Table 27-48. Verify Backdoor Access Key Command FCCOB Requirements
FCCOB Number

FCCOB Contents [7:0]

0

0x45 (VFYKEY)

Flash Configuration Field Offset Address

1-3

Not Used

4

Key Byte 0

0x0_0000

5

Key Byte 1

0x0_0001

6

Key Byte 2

0x0_0002

7

Key Byte 3

0x0_0003

8

Key Byte 4

0x0_0004

9

Key Byte 5

0x0_0005

A

Key Byte 6

0x0_0006

B

Key Byte 7

0x0_0007

After clearing CCIF to launch the Verify Backdoor Access Key command, the flash
memory module checks the FSEC[KEYEN] bits to verify that this command is enabled.
If not enabled, the flash memory module sets the FSTAT[ACCERR] bit and terminates.
If the command is enabled, the flash memory module compares the key provided in
FCCOB to the backdoor comparison key in the Flash Configuration Field. If the
backdoor keys match, the FSEC[SEC] field is changed to the unsecure state and security
is released. If the backdoor keys do not match, security is not released and all future
attempts to execute the Verify Backdoor Access Key command are immediately aborted
and the FSTAT[ACCERR] bit is (again) set to 1 until a reset of the flash memory module
module occurs. If the entire 8-byte key is all zeros or all ones, the Verify Backdoor
Access Key command fails with an access error. The CCIF flag is set after the Verify
Backdoor Access Key operation completes.
Table 27-49. Verify Backdoor Access Key Command Error Handling
Error Condition

Error Bit

The supplied key is all-0s or all-Fs

FSTAT[ACCERR]

An incorrect backdoor key is supplied

FSTAT[ACCERR]
Table continues on the next page...

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Functional Description

Table 27-49. Verify Backdoor Access Key Command Error Handling (continued)
Error Condition

Error Bit

Backdoor key access has not been enabled (see the description of the FSEC register)

FSTAT[ACCERR]

This command is launched and the backdoor key has mismatched since the last power down
reset

FSTAT[ACCERR]

27.4.11 Security
The flash memory module provides security information to the MCU based on contents
of the FSEC security register. The MCU then limits access to flash memory resources as
defined in the device's Chip Configuration details. During reset, the flash memory
module initializes the FSEC register using data read from the security byte of the Flash
Configuration Field (see Flash Configuration Field Description).
The following fields are available in the FSEC register. The settings are described in the
Flash Security Register (FTFA_FSEC) details.
Table 27-50. FSEC register fields
FSEC field

Description

KEYEN

Backdoor Key Access

MEEN

Mass Erase Capability

FSLACC

Freescale Factory Access

SEC

MCU security

27.4.11.1 Flash Memory Access by Mode and Security
The following table summarizes how access to the flash memory module is affected by
security and operating mode.
Table 27-51. Flash Memory Access Summary
Operating Mode

Chip Security State
Unsecure

NVM Normal
NVM Special

Secure
Full command set

Full command set

Only the Erase All Blocks and Read 1s All
Blocks commands.

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Chapter 27 Flash Memory Module (FTFA)

27.4.11.2 Changing the Security State
The security state out of reset can be permanently changed by programming the security
byte of the flash configuration field. This assumes that you are starting from a mode
where the necessary program flash erase and program commands are available and that
the region of the program flash containing the flash configuration field is unprotected. If
the flash security byte is successfully programmed, its new value takes affect after the
next chip reset.
27.4.11.2.1

Unsecuring the Chip Using Backdoor Key Access

The chip can be unsecured by using the backdoor key access feature, which requires
knowledge of the contents of the 8-byte backdoor key value stored in the Flash
Configuration Field (see Flash Configuration Field Description). If the FSEC[KEYEN]
bits are in the enabled state, the Verify Backdoor Access Key command (see Verify
Backdoor Access Key Command) can be run; it allows the user to present prospective
keys for comparison to the stored keys. If the keys match, the FSEC[SEC] bits are
changed to unsecure the chip. The entire 8-byte key cannot be all 0s or all 1s; that is,
0000_0000_0000_0000h and FFFF_FFFF_FFFF_FFFFh are not accepted by the Verify
Backdoor Access Key command as valid comparison values. While the Verify Backdoor
Access Key command is active, program flash memory is not available for read access
and returns invalid data.
The user code stored in the program flash memory must have a method of receiving the
backdoor keys from an external stimulus. This external stimulus would typically be
through one of the on-chip serial ports.
If the KEYEN bits are in the enabled state, the chip can be unsecured by the following
backdoor key access sequence:
1. Follow the command sequence for the Verify Backdoor Access Key command as
explained in Verify Backdoor Access Key Command
2. If the Verify Backdoor Access Key command is successful, the chip is unsecured and
the FSEC[SEC] bits are forced to the unsecure state
An illegal key provided to the Verify Backdoor Access Key command prohibits further
use of the Verify Backdoor Access Key command. A reset of the chip is the only method
to re-enable the Verify Backdoor Access Key command when a comparison fails.
After the backdoor keys have been correctly matched, the chip is unsecured by changing
the FSEC[SEC] bits. A successful execution of the Verify Backdoor Access Key
command changes the security in the FSEC register only. It does not alter the security
byte or the keys stored in the Flash Configuration Field (Flash Configuration Field
Description). After the next reset of the chip, the security state of the flash memory
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Functional Description

module reverts back to the flash security byte in the Flash Configuration Field. The
Verify Backdoor Access Key command sequence has no effect on the program and erase
protections defined in the program flash protection registers.
If the backdoor keys successfully match, the unsecured chip has full control of the
contents of the Flash Configuration Field. The chip may erase the sector containing the
Flash Configuration Field and reprogram the flash security byte to the unsecure state and
change the backdoor keys to any desired value.

27.4.12 Reset Sequence
On each system reset the flash memory module executes a sequence which establishes
initial values for the flash block configuration parameters, FPROT, FOPT, and FSEC
registers.
FSTAT[CCIF] is cleared throughout the reset sequence. The flash memory module holds
off CPU access during the reset sequence. Flash reads are possible when the hold is
removed. Completion of the reset sequence is marked by setting CCIF which enables
flash user commands.
If a reset occurs while any flash command is in progress, that command is immediately
aborted. The state of the word being programmed or the sector/block being erased is not
guaranteed. Commands and operations do not automatically resume after exiting reset.

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Chapter 28
Analog-to-Digital Converter (ADC)
28.1 Introduction
NOTE
For the chip-specific implementation details of this module's
instances see the chip configuration information.
The 16-bit analog-to-digital converter (ADC) is a successive approximation ADC
designed for operation within an integrated microcontroller system-on-chip.
NOTE
For the chip specific modes of operation, see the power
management information of the device.

28.1.1 Features
Features of the ADC module include:
• Linear successive approximation algorithm with up to 16-bit resolution
• Up to four pairs of differential and 24 single-ended external analog inputs
• Output modes:
• differential 16-bit, 13-bit, 11-bit, and 9-bit modes
• single-ended 16-bit, 12-bit, 10-bit, and 8-bit modes
• Output format in 2's complement 16-bit sign extended for differential modes
• Output in right-justified unsigned format for single-ended
• Single or continuous conversion, that is, automatic return to idle after single
conversion

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Introduction

• Configurable sample time and conversion speed/power
• Conversion complete/hardware average complete flag and interrupt
• Input clock selectable from up to four sources
• Operation in Low-Power modes for lower noise
• Asynchronous clock source for lower noise operation with option to output the clock
• Selectable hardware conversion trigger with hardware channel select
• Automatic compare with interrupt for less-than, greater-than or equal-to, within
range, or out-of-range, programmable value
• Temperature sensor
• Hardware average function
• Selectable voltage reference: external or alternate
• Self-Calibration mode

28.1.2 Block diagram
The following figure is the ADC module block diagram.

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Chapter 28 Analog-to-Digital Converter (ADC)
ADHWTSA

SC1A
Conversion
trigger
control

ADHWTSn

SC1n
ADTRG

ADHWT

Control Registers (SC2, CFG1, CFG2)
ADACKEN
Async
Clock Gen

A D IC L K

A D IV

ADLPC/ADHSC

MODE

ADLSMP/ADLSTS

DIFF

ADCO

trig g e r

c o m p le te

AIEN

COCO

ADCH

C o m p a re tru e 1

Interrupt

AD23
TempP

ADCK

ADACK

Clock
divide

Bus clock
2
ALTCLK

abort

convert

DADP3
AD4

sample

initialize

DADP0

transfer

Control sequencer

MCU STOP

A D V IN P

PG, MG

A D V IN M

CLPx

SAR converter

PG, MG
CLPx

CLM x

DADM0

Offset subtractor

CLMx

OFS

ADCOFS

Calibration
CALF

CAL

DADM3
AVGE, AVGS

Averager

V REFSH

TempM

Formatting

V REFH

SC3

MODE

CFG1,2

D

RA

VALTH

V REFSL

tra n s fe r

V REFL

Rn

VALTL

Compare
logic

C V1

ACFE
ACFGT, ACREN
Compare true

SC2
1

CV2

CV1:CV2

Figure 28-1. ADC block diagram

28.2 ADC Signal Descriptions
The ADC module supports up to 4 pairs of differential inputs and up to 24 single-ended
inputs. Each differential pair requires two inputs, DADPx and DADMx. The ADC also
requires four supply/reference/ground connections.
NOTE
Refer to ADC configuration section in chip configuration
chapter for the number of channels supported on this device.

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ADC Signal Descriptions

Table 28-1. ADC Signal Descriptions
Signal

Description

I/O

DADP3–DADP0

Differential Analog Channel Inputs

I

DADM3–DADM0

Differential Analog Channel Inputs

I

Single-Ended Analog Channel Inputs

I

VREFSH

Voltage Reference Select High

I

VREFSL

Voltage Reference Select Low

I

VDDA

Analog Power Supply

I

VSSA

Analog Ground

I

ADn

28.2.1 Analog Power (VDDA)
The ADC analog portion uses VDDA as its power connection. In some packages, VDDA is
connected internally to VDD. If externally available, connect the VDDA pin to the same
voltage potential as VDD. External filtering may be necessary to ensure clean VDDA for
good results.

28.2.2 Analog Ground (VSSA)
The ADC analog portion uses VSSA as its ground connection. In some packages, VSSA is
connected internally to VSS. If externally available, connect the VSSA pin to the same
voltage potential as VSS.

28.2.3 Voltage Reference Select
VREFSH and VREFSL are the high and low reference voltages for the ADC module.
The ADC can be configured to accept one of two voltage reference pairs for VREFSH and
VREFSL. Each pair contains a positive reference that must be between the minimum Ref
Voltage High and VDDA, and a ground reference that must be at the same potential as
VSSA. The two pairs are external (VREFH and VREFL) and alternate (VALTH and VALTL).
These voltage references are selected using SC2[REFSEL]. The alternate VALTH and
VALTL voltage reference pair may select additional external pins or internal sources
depending on MCU configuration. See the chip configuration information on the Voltage
References specific to this MCU.

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Chapter 28 Analog-to-Digital Converter (ADC)

In some packages, VREFH is connected in the package to VDDA and VREFL to VSSA. If
externally available, the positive reference(s) may be connected to the same potential as
VDDA or may be driven by an external source to a level between the minimum Ref
Voltage High and the VDDA potential. VREFH must never exceed VDDA. Connect the
ground references to the same voltage potential as VSSA.

28.2.4 Analog Channel Inputs (ADx)
The ADC module supports up to 24 single-ended analog inputs. A single-ended input is
selected for conversion through the SC1[ADCH] channel select bits when SC1n[DIFF] is
low.

28.2.5 Differential Analog Channel Inputs (DADx)
The ADC module supports up to four differential analog channel inputs. Each differential
analog input is a pair of external pins, DADPx and DADMx, referenced to each other to
provide the most accurate analog to digital readings. A differential input is selected for
conversion through SC1[ADCH] when SC1n[DIFF] is high. All DADPx inputs may be
used as single-ended inputs if SC1n[DIFF] is low. In certain MCU configurations, some
DADMx inputs may also be used as single-ended inputs if SC1n[DIFF] is low. See the
chip configuration chapter for ADC connections specific to this MCU.

28.3 Register definition
This section describes the ADC registers.
ADC memory map
Absolute
address
(hex)

Register name

Width
Access
(in bits)

Reset value

Section/
page

4003_B000

ADC Status and Control Registers 1 (ADC0_SC1A)

32

R/W

0000_001Fh

28.3.1/462

4003_B004

ADC Status and Control Registers 1 (ADC0_SC1B)

32

R/W

0000_001Fh

28.3.1/462

4003_B008

ADC Configuration Register 1 (ADC0_CFG1)

32

R/W

0000_0000h

28.3.2/465

4003_B00C ADC Configuration Register 2 (ADC0_CFG2)

32

R/W

0000_0000h

28.3.3/467

4003_B010

ADC Data Result Register (ADC0_RA)

32

R

0000_0000h

28.3.4/468

4003_B014

ADC Data Result Register (ADC0_RB)

32

R

0000_0000h

28.3.4/468

4003_B018

Compare Value Registers (ADC0_CV1)

32

R/W

0000_0000h

28.3.5/469

4003_B01C Compare Value Registers (ADC0_CV2)

32

R/W

0000_0000h

28.3.5/469

Table continues on the next page...

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Register definition

ADC memory map (continued)
Absolute
address
(hex)

Register name

Width
Access
(in bits)

Reset value

Section/
page

4003_B020

Status and Control Register 2 (ADC0_SC2)

32

R/W

0000_0000h

28.3.6/470

4003_B024

Status and Control Register 3 (ADC0_SC3)

32

R/W

0000_0000h

28.3.7/472

4003_B028

ADC Offset Correction Register (ADC0_OFS)

32

R/W

0000_0004h

28.3.8/474

4003_B02C ADC Plus-Side Gain Register (ADC0_PG)

32

R/W

0000_8200h

28.3.9/474

4003_B030

ADC Minus-Side Gain Register (ADC0_MG)

32

R/W

0000_8200h

28.3.10/475

4003_B034

ADC Plus-Side General Calibration Value Register
(ADC0_CLPD)

32

R/W

0000_000Ah 28.3.11/475

4003_B038

ADC Plus-Side General Calibration Value Register
(ADC0_CLPS)

32

R/W

0000_0020h

28.3.12/476

4003_B03C

ADC Plus-Side General Calibration Value Register
(ADC0_CLP4)

32

R/W

0000_0200h

28.3.13/476

4003_B040

ADC Plus-Side General Calibration Value Register
(ADC0_CLP3)

32

R/W

0000_0100h

28.3.14/477

4003_B044

ADC Plus-Side General Calibration Value Register
(ADC0_CLP2)

32

R/W

0000_0080h

28.3.15/477

4003_B048

ADC Plus-Side General Calibration Value Register
(ADC0_CLP1)

32

R/W

0000_0040h

28.3.16/478

4003_B04C

ADC Plus-Side General Calibration Value Register
(ADC0_CLP0)

32

R/W

0000_0020h

28.3.17/478

4003_B054

ADC Minus-Side General Calibration Value Register
(ADC0_CLMD)

32

R/W

0000_000Ah 28.3.18/479

4003_B058

ADC Minus-Side General Calibration Value Register
(ADC0_CLMS)

32

R/W

0000_0020h

28.3.19/479

4003_B05C

ADC Minus-Side General Calibration Value Register
(ADC0_CLM4)

32

R/W

0000_0200h

28.3.20/480

4003_B060

ADC Minus-Side General Calibration Value Register
(ADC0_CLM3)

32

R/W

0000_0100h

28.3.21/480

4003_B064

ADC Minus-Side General Calibration Value Register
(ADC0_CLM2)

32

R/W

0000_0080h

28.3.22/481

4003_B068

ADC Minus-Side General Calibration Value Register
(ADC0_CLM1)

32

R/W

0000_0040h

28.3.23/481

4003_B06C

ADC Minus-Side General Calibration Value Register
(ADC0_CLM0)

32

R/W

0000_0020h

28.3.24/482

28.3.1 ADC Status and Control Registers 1 (ADCx_SC1n)
SC1A is used for both software and hardware trigger modes of operation.
To allow sequential conversions of the ADC to be triggered by internal peripherals, the
ADC can have more then one status and control register: one for each conversion. The
SC1B–SC1n registers indicate potentially multiple SC1 registers for use only in hardware

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Chapter 28 Analog-to-Digital Converter (ADC)

trigger mode. See the chip configuration information about the number of SC1n registers
specific to this device. The SC1n registers have identical fields, and are used in a "pingpong" approach to control ADC operation.
At any one point in time, only one of the SC1n registers is actively controlling ADC
conversions. Updating SC1A while SC1n is actively controlling a conversion is allowed,
and vice-versa for any of the SC1n registers specific to this MCU.
Writing SC1A while SC1A is actively controlling a conversion aborts the current
conversion. In Software Trigger mode, when SC2[ADTRG]=0, writes to SC1A
subsequently initiate a new conversion, if SC1[ADCH] contains a value other than all 1s.
Writing any of the SC1n registers while that specific SC1n register is actively controlling
a conversion aborts the current conversion. None of the SC1B-SC1n registers are used for
software trigger operation and therefore writes to the SC1B–SC1n registers do not initiate
a new conversion.
Address: 4003_B000h base + 0h offset + (4d × i), where i=0d to 1d
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

0

R

W

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Bit

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

AIEN

DIFF

0

0

1

1

COCO

Reset

0

R

ADCH

W

Reset

0

0

0

0

0

0

0

0

0

1

1

1

ADCx_SC1n field descriptions
Field
31–8
Reserved
7
COCO

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
Conversion Complete Flag
Table continues on the next page...

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Register definition

ADCx_SC1n field descriptions (continued)
Field

Description
This is a read-only field that is set each time a conversion is completed when the compare function is
disabled, or SC2[ACFE]=0 and the hardware average function is disabled, or SC3[AVGE]=0. When the
compare function is enabled, or SC2[ACFE]=1, COCO is set upon completion of a conversion only if the
compare result is true. When the hardware average function is enabled, or SC3[AVGE]=1, COCO is set
upon completion of the selected number of conversions (determined by AVGS). COCO in SC1A is also set
at the completion of a calibration sequence. COCO is cleared when the respective SC1n register is written
or when the respective Rn register is read.
0
1

6
AIEN

Interrupt Enable
Enables conversion complete interrupts. When COCO becomes set while the respective AIEN is high, an
interrupt is asserted.
0
1

5
DIFF

Conversion complete interrupt is disabled.
Conversion complete interrupt is enabled.

Differential Mode Enable
Configures the ADC to operate in differential mode. When enabled, this mode automatically selects from
the differential channels, and changes the conversion algorithm and the number of cycles to complete a
conversion.
0
1

4–0
ADCH

Conversion is not completed.
Conversion is completed.

Single-ended conversions and input channels are selected.
Differential conversions and input channels are selected.

Input channel select
Selects one of the input channels. The input channel decode depends on the value of DIFF. DAD0-DAD3
are associated with the input pin pairs DADPx and DADMx.
NOTE: Some of the input channel options in the bitfield-setting descriptions might not be available for
your device. For the actual ADC channel assignments for your device, see the Chip Configuration
details.
The successive approximation converter subsystem is turned off when the channel select bits are all set,
that is, ADCH = 11111. This feature allows explicit disabling of the ADC and isolation of the input channel
from all sources. Terminating continuous conversions this way prevents an additional single conversion
from being performed. It is not necessary to set ADCH to all 1s to place the ADC in a low-power state
when continuous conversions are not enabled because the module automatically enters a low-power state
when a conversion completes.
00000
00001
00010
00011
00100
00101
00110
00111
01000
01001
01010
01011

When DIFF=0, DADP0 is selected as input; when DIFF=1, DAD0 is selected as input.
When DIFF=0, DADP1 is selected as input; when DIFF=1, DAD1 is selected as input.
When DIFF=0, DADP2 is selected as input; when DIFF=1, DAD2 is selected as input.
When DIFF=0, DADP3 is selected as input; when DIFF=1, DAD3 is selected as input.
When DIFF=0, AD4 is selected as input; when DIFF=1, it is reserved.
When DIFF=0, AD5 is selected as input; when DIFF=1, it is reserved.
When DIFF=0, AD6 is selected as input; when DIFF=1, it is reserved.
When DIFF=0, AD7 is selected as input; when DIFF=1, it is reserved.
When DIFF=0, AD8 is selected as input; when DIFF=1, it is reserved.
When DIFF=0, AD9 is selected as input; when DIFF=1, it is reserved.
When DIFF=0, AD10 is selected as input; when DIFF=1, it is reserved.
When DIFF=0, AD11 is selected as input; when DIFF=1, it is reserved.
Table continues on the next page...

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Chapter 28 Analog-to-Digital Converter (ADC)

ADCx_SC1n field descriptions (continued)
Field

Description
01100
01101
01110
01111
10000
10001
10010
10011
10100
10101
10110
10111
11000
11001
11010
11011
11100
11101
11110
11111

When DIFF=0, AD12 is selected as input; when DIFF=1, it is reserved.
When DIFF=0, AD13 is selected as input; when DIFF=1, it is reserved.
When DIFF=0, AD14 is selected as input; when DIFF=1, it is reserved.
When DIFF=0, AD15 is selected as input; when DIFF=1, it is reserved.
When DIFF=0, AD16 is selected as input; when DIFF=1, it is reserved.
When DIFF=0, AD17 is selected as input; when DIFF=1, it is reserved.
When DIFF=0, AD18 is selected as input; when DIFF=1, it is reserved.
When DIFF=0, AD19 is selected as input; when DIFF=1, it is reserved.
When DIFF=0, AD20 is selected as input; when DIFF=1, it is reserved.
When DIFF=0, AD21 is selected as input; when DIFF=1, it is reserved.
When DIFF=0, AD22 is selected as input; when DIFF=1, it is reserved.
When DIFF=0, AD23 is selected as input; when DIFF=1, it is reserved.
Reserved.
Reserved.
When DIFF=0, Temp Sensor (single-ended) is selected as input; when DIFF=1, Temp Sensor
(differential) is selected as input.
When DIFF=0,Bandgap (single-ended) is selected as input; when DIFF=1, Bandgap (differential)
is selected as input.
Reserved.
When DIFF=0,VREFSH is selected as input; when DIFF=1, -VREFSH (differential) is selected as
input. Voltage reference selected is determined by SC2[REFSEL].
When DIFF=0,VREFSL is selected as input; when DIFF=1, it is reserved. Voltage reference
selected is determined by SC2[REFSEL].
Module is disabled.

28.3.2 ADC Configuration Register 1 (ADCx_CFG1)
The configuration Register 1 (CFG1) selects the mode of operation, clock source, clock
divide, and configuration for low power or long sample time.
Address: 4003_B000h base + 8h offset = 4003_B008h
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

0

R

W

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Bit

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

ADLPC

0

R

W

Reset

0

0

0

0

0

0

0

0

0

ADLSMP

Reset

ADIV

0

0

0

MODE

0

0

ADICLK

0

0

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ADCx_CFG1 field descriptions
Field
31–8
Reserved
7
ADLPC

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
Low-Power Configuration
Controls the power configuration of the successive approximation converter. This optimizes power
consumption when higher sample rates are not required.
0
1

6–5
ADIV

Clock Divide Select
ADIV selects the divide ratio used by the ADC to generate the internal clock ADCK.
00
01
10
11

4
ADLSMP

ADLSMP selects between different sample times based on the conversion mode selected. This bit adjusts
the sample period to allow higher impedance inputs to be accurately sampled or to maximize conversion
speed for lower impedance inputs. Longer sample times can also be used to lower overall power
consumption if continuous conversions are enabled and high conversion rates are not required. When
ADLSMP=1, the long sample time select bits, (ADLSTS[1:0]), can select the extent of the long sample
time.
Short sample time.
Long sample time.

Conversion mode selection
Selects the ADC resolution mode.
00
01
10
11

1–0
ADICLK

The divide ratio is 1 and the clock rate is input clock.
The divide ratio is 2 and the clock rate is (input clock)/2.
The divide ratio is 4 and the clock rate is (input clock)/4.
The divide ratio is 8 and the clock rate is (input clock)/8.

Sample time configuration

0
1
3–2
MODE

Normal power configuration.
Low-power configuration. The power is reduced at the expense of maximum clock speed.

When DIFF=0:It is single-ended 8-bit conversion; when DIFF=1, it is differential 9-bit conversion with
2's complement output.
When DIFF=0:It is single-ended 12-bit conversion ; when DIFF=1, it is differential 13-bit conversion
with 2's complement output.
When DIFF=0:It is single-ended 10-bit conversion ; when DIFF=1, it is differential 11-bit conversion
with 2's complement output.
When DIFF=0:It is single-ended 16-bit conversion; when DIFF=1, it is differential 16-bit conversion
with 2's complement output.

Input Clock Select
Selects the input clock source to generate the internal clock, ADCK. Note that when the ADACK clock
source is selected, it is not required to be active prior to conversion start. When it is selected and it is not
active prior to a conversion start, when CFG2[ADACKEN]=0, the asynchronous clock is activated at the
start of a conversion and deactivated when conversions are terminated. In this case, there is an
associated clock startup delay each time the clock source is re-activated.
00
01
10
11

Bus clock
(Bus clock)/2
Alternate clock (ALTCLK)
Asynchronous clock (ADACK)

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Chapter 28 Analog-to-Digital Converter (ADC)

28.3.3 ADC Configuration Register 2 (ADCx_CFG2)
Configuration Register 2 (CFG2) selects the special high-speed configuration for very
high speed conversions and selects the long sample time duration during long sample
mode.
Address: 4003_B000h base + Ch offset = 4003_B00Ch
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

0

R

Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Bit

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

MUXSEL

ADACKEN

ADHSC

W

0

0

0

0

R

0

W

Reset

0

0

0

0

0

0

0

0

0

0

0

ADLSTS

0

0

ADCx_CFG2 field descriptions
Field

Description

31–8
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

7–5
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

4
MUXSEL

ADC Mux Select
Changes the ADC mux setting to select between alternate sets of ADC channels.
0
1

3
ADACKEN

Asynchronous Clock Output Enable
Enables the asynchronous clock source and the clock source output regardless of the conversion and
status of CFG1[ADICLK]. Based on MCU configuration, the asynchronous clock may be used by other
modules. See chip configuration information. Setting this field allows the clock to be used even while the
ADC is idle or operating from a different clock source. Also, latency of initiating a single or first-continuous
conversion with the asynchronous clock selected is reduced because the ADACK clock is already
operational.
0
1

2
ADHSC

ADxxa channels are selected.
ADxxb channels are selected.

Asynchronous clock output disabled; Asynchronous clock is enabled only if selected by ADICLK and a
conversion is active.
Asynchronous clock and clock output is enabled regardless of the state of the ADC.

High-Speed Configuration
Table continues on the next page...

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Register definition

ADCx_CFG2 field descriptions (continued)
Field

Description
Configures the ADC for very high-speed operation. The conversion sequence is altered with 2 ADCK
cycles added to the conversion time to allow higher speed conversion clocks.
0
1

1–0
ADLSTS

Normal conversion sequence selected.
High-speed conversion sequence selected with 2 additional ADCK cycles to total conversion time.

Long Sample Time Select
Selects between the extended sample times when long sample time is selected, that is, when
CFG1[ADLSMP]=1. This allows higher impedance inputs to be accurately sampled or to maximize
conversion speed for lower impedance inputs. Longer sample times can also be used to lower overall
power consumption when continuous conversions are enabled if high conversion rates are not required.
00
01
10
11

Default longest sample time; 20 extra ADCK cycles; 24 ADCK cycles total.
12 extra ADCK cycles; 16 ADCK cycles total sample time.
6 extra ADCK cycles; 10 ADCK cycles total sample time.
2 extra ADCK cycles; 6 ADCK cycles total sample time.

28.3.4 ADC Data Result Register (ADCx_Rn)
The data result registers (Rn) contain the result of an ADC conversion of the channel
selected by the corresponding status and channel control register (SC1A:SC1n). For
every status and channel control register, there is a corresponding data result register.
Unused bits in R n are cleared in unsigned right-justified modes and carry the sign bit
(MSB) in sign-extended 2's complement modes. For example, when configured for 10-bit
single-ended mode, D[15:10] are cleared. When configured for 11-bit differential mode,
D[15:10] carry the sign bit, that is, bit 10 extended through bit 15.
The following table describes the behavior of the data result registers in the different
modes of operation.
Table 28-43. Data result register description
Conversion
mode

D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0

Format

16-bit differential

S

D

D

D

D

D

D

D

D

D

D

D

D

D

D

D

Signed 2's
complement

16-bit singleended

D

D

D

D

D

D

D

D

D

D

D

D

D

D

D

D

Unsigned right
justified

13-bit differential

S

S

S

S

D

D

D

D

D

D

D

D

D

D

D

D

Sign-extended
2's complement

12-bit singleended

0

0

0

0

D

D

D

D

D

D

D

D

D

D

D

D

Unsigned rightjustified

11-bit differential

S

S

S

S

S

S

D

D

D

D

D

D

D

D

D

D

Sign-extended
2's complement

Table continues on the next page...

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Chapter 28 Analog-to-Digital Converter (ADC)

Table 28-43. Data result register description (continued)
Conversion
mode

D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0

Format

10-bit singleended

0

0

0

0

0

0

D

D

D

D

D

D

D

D

D

D

Unsigned rightjustified

9-bit differential

S

S

S

S

S

S

S

S

D

D

D

D

D

D

D

D

Sign-extended
2's complement

8-bit singleended

0

0

0

0

0

0

0

0

D

D

D

D

D

D

D

D

Unsigned rightjustified

NOTE
S: Sign bit or sign bit extension;
D: Data, which is 2's complement data if indicated
Address: 4003_B000h base + 10h offset + (4d × i), where i=0d to 1d
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

0

R

7

6

5

4

3

2

1

0

0

0

0

0

0

0

0

0

D

W
Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

ADCx_Rn field descriptions
Field
31–16
Reserved
15–0
D

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
Data result

28.3.5 Compare Value Registers (ADCx_CVn)
The compare value registers (CV1 and CV2) contain a compare value used to compare
the conversion result when the compare function is enabled, that is, SC2[ACFE]=1. This
register is formatted in the same way as the Rn registers in different modes of operation
for both bit position definition and value format using unsigned or sign-extended 2's
complement. Therefore, the compare function uses only the CVn fields that are related to
the ADC mode of operation.
The compare value 2 register (CV2) is used only when the compare range function is
enabled, that is, SC2[ACREN]=1.

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Register definition
Address: 4003_B000h base + 18h offset + (4d × i), where i=0d to 1d
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

0

R

0

0

0

0

0

0

0

0

6

5

4

3

2

1

0

0

0

0

0

0

0

0

CV

W
Reset

7

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

ADCx_CVn field descriptions
Field

Description

31–16
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

15–0
CV

Compare Value.

28.3.6 Status and Control Register 2 (ADCx_SC2)
The status and control register 2 (SC2) contains the conversion active, hardware/software
trigger select, compare function, and voltage reference select of the ADC module.
Address: 4003_B000h base + 20h offset = 4003_B020h
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

0

R

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Bit

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

ACFE

ACFGT

ACREN

DMAEN

0

0

0

0

0

ADACT

Reset

ADTRG

W

0

R

REFSEL

W

Reset

0

0

0

0

0

0

0

0

0

0

0

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Chapter 28 Analog-to-Digital Converter (ADC)

ADCx_SC2 field descriptions
Field
31–8
Reserved
7
ADACT

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
Conversion Active
Indicates that a conversion or hardware averaging is in progress. ADACT is set when a conversion is
initiated and cleared when a conversion is completed or aborted.
0
1

6
ADTRG

Conversion Trigger Select
Selects the type of trigger used for initiating a conversion. Two types of trigger are selectable:
• Software trigger: When software trigger is selected, a conversion is initiated following a write to
SC1A.
• Hardware trigger: When hardware trigger is selected, a conversion is initiated following the assertion
of the ADHWT input after a pulse of the ADHWTSn input.
0
1

5
ACFE

Enables the compare function.
Compare function disabled.
Compare function enabled.

Compare Function Greater Than Enable
Configures the compare function to check the conversion result relative to the CV1 and CV2 based upon
the value of ACREN. ACFE must be set for ACFGT to have any effect.
0
1

3
ACREN

Software trigger selected.
Hardware trigger selected.

Compare Function Enable

0
1
4
ACFGT

Conversion not in progress.
Conversion in progress.

Configures less than threshold, outside range not inclusive and inside range not inclusive; functionality
based on the values placed in CV1 and CV2.
Configures greater than or equal to threshold, outside and inside ranges inclusive; functionality based
on the values placed in CV1 and CV2.

Compare Function Range Enable
Configures the compare function to check if the conversion result of the input being monitored is either
between or outside the range formed by CV1 and CV2 determined by the value of ACFGT. ACFE must be
set for ACFGT to have any effect.
0
1

Range function disabled. Only CV1 is compared.
Range function enabled. Both CV1 and CV2 are compared.

2
DMAEN

DMA Enable

1–0
REFSEL

Voltage Reference Selection

0
1

DMA is disabled.
DMA is enabled and will assert the ADC DMA request during an ADC conversion complete event
noted when any of the SC1n[COCO] flags is asserted.

Selects the voltage reference source used for conversions.
00

Default voltage reference pin pair, that is, external pins VREFH and VREFL
Table continues on the next page...

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Register definition

ADCx_SC2 field descriptions (continued)
Field

Description
01

10
11

Alternate reference pair, that is, VALTH and VALTL . This pair may be additional external pins or
internal sources depending on the MCU configuration. See the chip configuration information for
details specific to this MCU
Reserved
Reserved

28.3.7 Status and Control Register 3 (ADCx_SC3)
The Status and Control Register 3 (SC3) controls the calibration, continuous convert, and
hardware averaging functions of the ADC module.
Address: 4003_B000h base + 24h offset = 4003_B024h
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

0

R

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Bit

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

AVGE

0

0

CALF

Reset

ADCO

W

0

R

0

CAL

AVGS

W

Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

ADCx_SC3 field descriptions
Field
31–8
Reserved

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
Table continues on the next page...

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Chapter 28 Analog-to-Digital Converter (ADC)

ADCx_SC3 field descriptions (continued)
Field
7
CAL

6
CALF

Description
Calibration
Begins the calibration sequence when set. This field stays set while the calibration is in progress and is
cleared when the calibration sequence is completed. CALF must be checked to determine the result of the
calibration sequence. Once started, the calibration routine cannot be interrupted by writes to the ADC
registers or the results will be invalid and CALF will set. Setting CAL will abort any current conversion.
Calibration Failed Flag
Displays the result of the calibration sequence. The calibration sequence will fail if SC2[ADTRG] = 1, any
ADC register is written, or any stop mode is entered before the calibration sequence completes. Writing 1
to CALF clears it.
0
1

5–4
Reserved
3
ADCO

This field is reserved.
This read-only field is reserved and always has the value 0.
Continuous Conversion Enable
Enables continuous conversions.
0
1

2
AVGE

One conversion or one set of conversions if the hardware average function is enabled, that is,
AVGE=1, after initiating a conversion.
Continuous conversions or sets of conversions if the hardware average function is enabled, that is,
AVGE=1, after initiating a conversion.

Hardware Average Enable
Enables the hardware average function of the ADC.
0
1

1–0
AVGS

Calibration completed normally.
Calibration failed. ADC accuracy specifications are not guaranteed.

Hardware average function disabled.
Hardware average function enabled.

Hardware Average Select
Determines how many ADC conversions will be averaged to create the ADC average result.
00
01
10
11

4 samples averaged.
8 samples averaged.
16 samples averaged.
32 samples averaged.

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Register definition

28.3.8 ADC Offset Correction Register (ADCx_OFS)
The ADC Offset Correction Register (OFS) contains the user-selected or calibrationgenerated offset error correction value. This register is a 2’s complement, left-justified,
16-bit value . The value in OFS is subtracted from the conversion and the result is
transferred into the result registers, Rn. If the result is greater than the maximum or less
than the minimum result value, it is forced to the appropriate limit for the current mode of
operation.
Address: 4003_B000h base + 28h offset = 4003_B028h
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

0

R

0

0

0

0

0

0

0

0

7

6

5

4

3

2

1

0

0

0

0

0

1

0

0

OFS

W
Reset

8

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

ADCx_OFS field descriptions
Field

Description

31–16
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

15–0
OFS

Offset Error Correction Value

28.3.9 ADC Plus-Side Gain Register (ADCx_PG)
The Plus-Side Gain Register (PG) contains the gain error correction for the plus-side
input in differential mode or the overall conversion in single-ended mode. PG, a 16-bit
real number in binary format, is the gain adjustment factor, with the radix point fixed
between ADPG15 and ADPG14. This register must be written by the user with the value
described in the calibration procedure. Otherwise, the gain error specifications may not
be met.
Address: 4003_B000h base + 2Ch offset = 4003_B02Ch
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

0

R

0

0

0

0

0

0

0

0

7

6

5

4

3

2

1

0

0

0

0

0

0

0

0

PG

W
Reset

8

0

0

0

0

0

0

0

0

1

0

0

0

0

0

1

0

0

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Chapter 28 Analog-to-Digital Converter (ADC)

ADCx_PG field descriptions
Field

Description

31–16
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

15–0
PG

Plus-Side Gain

28.3.10 ADC Minus-Side Gain Register (ADCx_MG)
The Minus-Side Gain Register (MG) contains the gain error correction for the minus-side
input in differential mode. This register is ignored in single-ended mode. MG, a 16-bit
real number in binary format, is the gain adjustment factor, with the radix point fixed
between ADMG15 and ADMG14. This register must be written by the user with the
value described in the calibration procedure. Otherwise, the gain error specifications may
not be met.
Address: 4003_B000h base + 30h offset = 4003_B030h
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

0

R

0

0

0

0

0

0

0

0

7

6

5

4

3

2

1

0

0

0

0

0

0

0

0

MG

W
Reset

8

0

0

0

0

0

0

0

0

1

0

0

0

0

0

1

0

0

ADCx_MG field descriptions
Field
31–16
Reserved
15–0
MG

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
Minus-Side Gain

28.3.11 ADC Plus-Side General Calibration Value Register
(ADCx_CLPD)
The Plus-Side General Calibration Value Registers (CLPx) contain calibration
information that is generated by the calibration function. These registers contain seven
calibration values of varying widths: CLP0[5:0], CLP1[6:0], CLP2[7:0], CLP3[8:0],
CLP4[9:0], CLPS[5:0], and CLPD[5:0]. CLPx are automatically set when the selfcalibration sequence is done, that is, CAL is cleared. If these registers are written by the
user after calibration, the linearity error specifications may not be met.

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Register definition
Address: 4003_B000h base + 34h offset = 4003_B034h
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

0

R

0

0

0

0

0

0

0

0

0

0

0

0

0

2

1

0

CLPD

W
Reset

3

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

1

0

1

0

4

3

2

1

0

ADCx_CLPD field descriptions
Field

Description

31–6
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

5–0
CLPD

Calibration Value

28.3.12 ADC Plus-Side General Calibration Value Register
(ADCx_CLPS)
For more information, see CLPD register description.
Address: 4003_B000h base + 38h offset = 4003_B038h
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

0

R

CLPS

W
Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

1

0

0

0

0

0

4

3

2

1

0

0

0

0

0

ADCx_CLPS field descriptions
Field

Description

31–6
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

5–0
CLPS

Calibration Value

28.3.13 ADC Plus-Side General Calibration Value Register
(ADCx_CLP4)
For more information, see CLPD register description.
Address: 4003_B000h base + 3Ch offset = 4003_B03Ch
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

0

R

CLP4

W
Reset

0

0

0

0

0

0

0

0

0

0

0

5

0

0

0

0

0

0

0

0

0

0

0

1

0

0

0

0

0

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ADCx_CLP4 field descriptions
Field

Description

31–10
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

9–0
CLP4

Calibration Value

28.3.14 ADC Plus-Side General Calibration Value Register
(ADCx_CLP3)
For more information, see CLPD register description.
Address: 4003_B000h base + 40h offset = 4003_B040h
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

0

R

0

0

0

0

0

0

0

0

0

0

0

3

2

1

0

0

0

0

0

0

4

3

2

1

0

0

0

0

CLP3

W
Reset

4

0

0

0

0

0

0

0

0

0

0

0

0

1

0

0

0

ADCx_CLP3 field descriptions
Field

Description

31–9
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

8–0
CLP3

Calibration Value

28.3.15 ADC Plus-Side General Calibration Value Register
(ADCx_CLP2)
For more information, see CLPD register description.
Address: 4003_B000h base + 44h offset = 4003_B044h
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

0

R

CLP2

W
Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

1

0

0

0

0

ADCx_CLP2 field descriptions
Field
31–8
Reserved
7–0
CLP2

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
Calibration Value

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Register definition

28.3.16 ADC Plus-Side General Calibration Value Register
(ADCx_CLP1)
For more information, see CLPD register description.
Address: 4003_B000h base + 48h offset = 4003_B048h
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

0

R

0

0

0

0

0

0

0

0

0

0

0

0

2

1

0

CLP1

W
Reset

3

0

0

0

0

0

0

0

0

0

0

0

0

0

1

0

0

0

0

0

0

4

3

2

1

0

0

0

ADCx_CLP1 field descriptions
Field

Description

31–7
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

6–0
CLP1

Calibration Value

28.3.17 ADC Plus-Side General Calibration Value Register
(ADCx_CLP0)
For more information, see CLPD register description.
Address: 4003_B000h base + 4Ch offset = 4003_B04Ch
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

0

R

CLP0

W
Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

1

0

0

0

ADCx_CLP0 field descriptions
Field
31–6
Reserved
5–0
CLP0

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
Calibration Value

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Chapter 28 Analog-to-Digital Converter (ADC)

28.3.18 ADC Minus-Side General Calibration Value Register
(ADCx_CLMD)
The Minus-Side General Calibration Value (CLMx) registers contain calibration
information that is generated by the calibration function. These registers contain seven
calibration values of varying widths: CLM0[5:0], CLM1[6:0], CLM2[7:0], CLM3[8:0],
CLM4[9:0], CLMS[5:0], and CLMD[5:0]. CLMx are automatically set when the selfcalibration sequence is done, that is, CAL is cleared. If these registers are written by the
user after calibration, the linearity error specifications may not be met.
Address: 4003_B000h base + 54h offset = 4003_B054h
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

0

R

0

0

0

0

0

0

0

0

0

0

0

0

0

2

1

0

CLMD

W
Reset

3

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

1

0

1

0

4

3

2

1

0

0

0

ADCx_CLMD field descriptions
Field

Description

31–6
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

5–0
CLMD

Calibration Value

28.3.19 ADC Minus-Side General Calibration Value Register
(ADCx_CLMS)
For more information, see CLMD register description.
Address: 4003_B000h base + 58h offset = 4003_B058h
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

0

R

CLMS

W
Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

1

0

0

0

ADCx_CLMS field descriptions
Field
31–6
Reserved
5–0
CLMS

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
Calibration Value

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Register definition

28.3.20 ADC Minus-Side General Calibration Value Register
(ADCx_CLM4)
For more information, see CLMD register description.
Address: 4003_B000h base + 5Ch offset = 4003_B05Ch
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

0

R

0

0

0

0

0

0

0

0

0

0

0

4

3

2

1

0

0

0

0

0

0

4

3

2

1

0

0

0

0

0

CLM4

W
Reset

5

0

0

0

0

0

0

0

0

0

0

0

1

0

0

0

0

ADCx_CLM4 field descriptions
Field

Description

31–10
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

9–0
CLM4

Calibration Value

28.3.21 ADC Minus-Side General Calibration Value Register
(ADCx_CLM3)
For more information, see CLMD register description.
Address: 4003_B000h base + 60h offset = 4003_B060h
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

0

R

CLM3

W
Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

1

0

0

0

0

ADCx_CLM3 field descriptions
Field
31–9
Reserved
8–0
CLM3

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
Calibration Value

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Chapter 28 Analog-to-Digital Converter (ADC)

28.3.22 ADC Minus-Side General Calibration Value Register
(ADCx_CLM2)
For more information, see CLMD register description.
Address: 4003_B000h base + 64h offset = 4003_B064h
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

0

R

0

0

0

0

0

0

0

0

0

0

0

0

3

2

1

0

CLM2

W
Reset

4

0

0

0

0

0

0

0

0

0

0

0

0

1

0

0

0

0

0

0

0

4

3

2

1

0

0

0

0

ADCx_CLM2 field descriptions
Field

Description

31–8
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

7–0
CLM2

Calibration Value

28.3.23 ADC Minus-Side General Calibration Value Register
(ADCx_CLM1)
For more information, see CLMD register description.
Address: 4003_B000h base + 68h offset = 4003_B068h
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

0

R

CLM1

W
Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

1

0

0

0

ADCx_CLM1 field descriptions
Field
31–7
Reserved
6–0
CLM1

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
Calibration Value

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28.3.24 ADC Minus-Side General Calibration Value Register
(ADCx_CLM0)
For more information, see CLMD register description.
Address: 4003_B000h base + 6Ch offset = 4003_B06Ch
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

0

R

0

0

0

0

0

0

0

0

0

0

0

0

0

2

1

0

0

0

CLM0

W
Reset

3

0

0

0

0

0

0

0

0

0

0

0

0

0

1

0

0

0

ADCx_CLM0 field descriptions
Field
31–6
Reserved
5–0
CLM0

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
Calibration Value

28.4 Functional description
The ADC module is disabled during reset, in Low-Power Stop mode, or when
SC1n[ADCH] are all high; see the power management information for details. The
module is idle when a conversion has completed and another conversion has not been
initiated. When it is idle and the asynchronous clock output enable is disabled, or
CFG2[ADACKEN]= 0, the module is in its lowest power state. The ADC can perform an
analog-to-digital conversion on any of the software selectable channels. All modes
perform conversion by a successive approximation algorithm.
To meet accuracy specifications, the ADC module must be calibrated using the on-chip
calibration function. See Calibration function for details on how to perform calibration.
When the conversion is completed, the result is placed in the Rn data registers. The
respective SC1n[COCO] is then set and an interrupt is generated if the respective
conversion complete interrupt has been enabled, or, when SC1n[AIEN]=1.
The ADC module has the capability of automatically comparing the result of a
conversion with the contents of the CV1 and CV2 registers. The compare function is
enabled by setting SC2[ACFE] and operates in any of the conversion modes and
configurations.

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Chapter 28 Analog-to-Digital Converter (ADC)

The ADC module has the capability of automatically averaging the result of multiple
conversions. The hardware average function is enabled by setting SC3[AVGE] and
operates in any of the conversion modes and configurations.
NOTE
For the chip specific modes of operation, see the power
management information of this MCU.

28.4.1 Clock select and divide control
One of four clock sources can be selected as the clock source for the ADC module. This
clock source is then divided by a configurable value to generate the input clock ADCK,
to the module. The clock is selected from one of the following sources by means of
CFG1[ADICLK].
• Bus clock. This is the default selection following reset.
• Bus clock divided by two. For higher bus clock rates, this allows a maximum divideby-16 of the bus clock using CFG1[ADIV].
• ALTCLK: As defined for this MCU. See the chip configuration information.
• Asynchronous clock (ADACK): This clock is generated from a clock source within
the ADC module. When the ADACK clock source is selected, it is not required to be
active prior to conversion start. When it is selected and it is not active prior to a
conversion start CFG2[ADACKEN]=0, ADACK is activated at the start of a
conversion and deactivated when conversions are terminated. In this case, there is an
associated clock startup delay each time the clock source is re-activated. To avoid the
conversion time variability and latency associated with the ADACK clock startup, set
CFG2[ADACKEN]=1 and wait the worst-case startup time of 5 µs prior to initiating
any conversions using the ADACK clock source. Conversions are possible using
ADACK as the input clock source while the MCU is in Normal Stop mode. See
Power Control for more information.
Whichever clock is selected, its frequency must fall within the specified frequency range
for ADCK. If the available clocks are too slow, the ADC may not perform according to
specifications. If the available clocks are too fast, the clock must be divided to the
appropriate frequency. This divider is specified by CFG1[ADIV] and can be divide-by 1,
2, 4, or 8.

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Functional description

28.4.2 Voltage reference selection
The ADC can be configured to accept one of the two voltage reference pairs as the
reference voltage (VREFSH and VREFSL) used for conversions. Each pair contains a
positive reference that must be between the minimum Ref Voltage High and VDDA, and a
ground reference that must be at the same potential as VSSA. The two pairs are external
(VREFH and VREFL) and alternate (VALTH and VALTL). These voltage references are
selected using SC2[REFSEL]. The alternate (VALTH and VALTL) voltage reference pair
may select additional external pins or internal sources depending on MCU configuration.
See the chip configuration information on the voltage references specific to this MCU.

28.4.3 Hardware trigger and channel selects
The ADC module has a selectable asynchronous hardware conversion trigger, ADHWT,
that is enabled when SC2[ADTRG] is set and a hardware trigger select event,
ADHWTSn, has occurred. This source is not available on all MCUs. See the Chip
Configuration chapter for information on the ADHWT source and the ADHWTSn
configurations specific to this MCU.
When an ADHWT source is available and hardware trigger is enabled, that is
SC2[ADTRG]=1, a conversion is initiated on the rising-edge of ADHWT after a
hardware trigger select event, that is, ADHWTSn, has occurred. If a conversion is in
progress when a rising-edge of a trigger occurs, the rising-edge is ignored. In continuous
convert configuration, only the initial rising-edge to launch continuous conversions is
observed, and until conversion is aborted, the ADC continues to do conversions on the
same SCn register that initiated the conversion. The hardware trigger function operates in
conjunction with any of the conversion modes and configurations.
The hardware trigger select event, that is, ADHWTSn, must be set prior to the receipt of
the ADHWT signal. If these conditions are not met, the converter may ignore the trigger
or use the incorrect configuration. If a hardware trigger select event is asserted during a
conversion, it must stay asserted until the end of current conversion and remain set until
the receipt of the ADHWT signal to trigger a new conversion. The channel and status
fields selected for the conversion depend on the active trigger select signal:
• ADHWTSA active selects SC1A
• ADHWTSn active selects SC1n
Note
Asserting more than one hardware trigger select signal
(ADHWTSn) at the same time results in unknown results. To
avoid this, select only one hardware trigger select signal
(ADHWTSn) prior to the next intended conversion.
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Chapter 28 Analog-to-Digital Converter (ADC)

When the conversion is completed, the result is placed in the Rn registers associated with
the ADHWTSn received. For example:
• ADHWTSA active selects RA register
• ADHWTSn active selects Rn register
The conversion complete flag associated with the ADHWTSn received, that is,
SC1n[COCO], is then set and an interrupt is generated if the respective conversion
complete interrupt has been enabled, that is, SC1[AIEN]=1.

28.4.4 Conversion control
Conversions can be performed as determined by CFG1[MODE] and SC1n[DIFF] as
shown in the description of CFG1[MODE].
Conversions can be initiated by a software or hardware trigger. In addition, the ADC
module can be configured for:
• Low-power operation
• Long sample time
• Continuous conversion
• Hardware average
• Automatic compare of the conversion result to a software determined compare value

28.4.4.1 Initiating conversions
A conversion is initiated:
• Following a write to SC1A, with SC1n[ADCH] not all 1's, if software triggered
operation is selected, that is, when SC2[ADTRG]=0.
• Following a hardware trigger, or ADHWT event, if hardware triggered operation is
selected, that is, SC2[ADTRG]=1, and a hardware trigger select event, ADHWTSn,
has occurred. The channel and status fields selected depend on the active trigger
select signal:
• ADHWTSA active selects SC1A
• ADHWTSn active selects SC1n
• if neither is active, the off condition is selected

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Functional description

Note
Selecting more than one ADHWTSn prior to a conversion
completion will result in unknown results. To avoid this,
select only one ADHWTSn prior to a conversion
completion.
• Following the transfer of the result to the data registers when continuous conversion
is enabled, that is, when ADCO=1.
If continuous conversions are enabled, a new conversion is automatically initiated after
the completion of the current conversion, by:. In software triggered operation, that is,
when ADTRG=0, continuous conversions begin after SC1A is written and continue until
aborted. In hardware triggered operation, that is, when ADTRG=1 and one ADHWTSn
event has occurred, continuous conversions begin after a hardware trigger event and
continue until aborted.
If hardware averaging is enabled, a new conversion is automatically initiated after the
completion of the current conversion until the correct number of conversions are
completed. In software triggered operation, conversions begin after SC1A is written. In
hardware triggered operation, conversions begin after a hardware trigger. If continuous
conversions are also enabled, a new set of conversions to be averaged are initiated
following the last of the selected number of conversions.

28.4.4.2 Completing conversions
A conversion is completed when the result of the conversion is transferred into the data
result registers, Rn. If the compare functions are disabled, this is indicated by setting of
SC1n[COCO]. If hardware averaging is enabled, the respective SC1n[COCO] sets only if
the last of the selected number of conversions is completed. If the compare function is
enabled, the respective SC1n[COCO] sets and conversion result data is transferred only if
the compare condition is true. If both hardware averaging and compare functions are
enabled, then the respective SC1n[COCO] sets only if the last of the selected number of
conversions is completed and the compare condition is true. An interrupt is generated if
the respective SC1n[AIEN] is high at the time that the respective SC1n[COCO] is set.

28.4.4.3 Aborting conversions
Any conversion in progress is aborted when:

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Chapter 28 Analog-to-Digital Converter (ADC)

• Writing to SC1A while it is actively controlling a conversion, aborts the current
conversion. In Software Trigger mode, when SC2[ADTRG]=0, a write to SC1A
initiates a new conversion if SC1A[ADCH] is equal to a value other than all 1s.
Writing to any of the SC1B–SC1n registers while that specific SC1B–SC1n register
is actively controlling a conversion aborts the current conversion. The SC1(B-n)
registers are not used for software trigger operation and therefore writes to the
SC1(B-n) registers do not initiate a new conversion.
• A write to any ADC register besides the SC1A-SC1n registers occurs. This indicates
that a change in mode of operation has occurred and the current conversion is
therefore invalid.
• The MCU is reset or enters Low-Power Stop modes.
• The MCU enters Normal Stop mode with ADACK not enabled.
When a conversion is aborted, the contents of the data registers, Rn, are not altered. The
data registers continue to be the values transferred after the completion of the last
successful conversion. If the conversion was aborted by a reset or Low-Power Stop
modes, RA and Rn return to their reset states.

28.4.4.4 Power control
The ADC module remains in its idle state until a conversion is initiated. If ADACK is
selected as the conversion clock source, but the asynchronous clock output is disabled,
that is CFG2[ADACKEN]=0, the ADACK clock generator also remains in its idle state
(disabled) until a conversion is initiated. If the asynchronous clock output is enabled, that
is, CFG2[ADACKEN]=1, it remains active regardless of the state of the ADC or the
MCU power mode.
Power consumption when the ADC is active can be reduced by setting CFG1[ADLPC].
This results in a lower maximum value for fADCK.

28.4.4.5 Sample time and total conversion time
For short sample, that is, when CFG1[ADLSMP]=0, there is a 2-cycle adder for first
conversion over the base sample time of four ADCK cycles. For high speed conversions,
that is, when CFG2[ADHSC]=1, there is an additional 2-cycle adder on any conversion.
The table below summarizes sample times for the possible ADC configurations.

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Functional description
ADC configuration

Sample time (ADCK cycles)

CFG1[ADLSMP]

CFG2[ADLSTS]

CFG2[ADHSC]

First or Single

Subsequent

0

X

0

6

4

1

00

0

24

1

01

0

16

1

10

0

10

1

11

0

6

0

X

1

1

00

1

26

1

01

1

18

1

10

1

12

1

11

1

8

8

6

The total conversion time depends upon:
• The sample time as determined by CFG1[ADLSMP] and CFG2[ADLSTS]
• The MCU bus frequency
• The conversion mode, as determined by CFG1[MODE] and SC1n[DIFF]
• The high speed configuration, that is, CFG2[ADHSC]
• The frequency of the conversion clock, that is, fADCK.
CFG2[ADHSC] is used to configure a higher clock input frequency. This will allow
faster overall conversion times. To meet internal ADC timing requirements,
CFG2[ADHSC] adds additional ADCK cycles. Conversions with CFG2[ADHSC]=1 take
two more ADCK cycles. CFG2[ADHSC] must be used when the ADCLK exceeds the
limit for CFG2[ADHSC]=0.
After the module becomes active, sampling of the input begins.
1. CFG1[ADLSMP] and CFG2[ADLSTS] select between sample times based on the
conversion mode that is selected.
2. When sampling is completed, the converter is isolated from the input channel and a
successive approximation algorithm is applied to determine the digital value of the
analog signal.
3. The result of the conversion is transferred to Rn upon completion of the conversion
algorithm.
If the bus frequency is less than fADCK, precise sample time for continuous conversions
cannot be guaranteed when short sample is enabled, that is, when CFG1[ADLSMP]=0.
The maximum total conversion time is determined by the clock source chosen and the
divide ratio selected. The clock source is selectable by CFG1[ADICLK], and the divide
ratio is specified by CFG1[ADIV].

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Chapter 28 Analog-to-Digital Converter (ADC)

The maximum total conversion time for all configurations is summarized in the equation
below. See the following tables for the variables referenced in the equation.

Figure 28-62. Conversion time equation
Table 28-70. Single or first continuous time adder (SFCAdder)
CFG1[AD
LSMP]

CFG2[AD
ACKEN]

CFG1[ADICLK]

Single or first continuous time adder (SFCAdder)

1

x

0x, 10

3 ADCK cycles + 5 bus clock cycles

1

1

11

3 ADCK cycles + 5 bus clock cycles1

1

0

11

5 μs + 3 ADCK cycles + 5 bus clock cycles

0

x

0x, 10

5 ADCK cycles + 5 bus clock cycles

0

1

11

5 ADCK cycles + 5 bus clock cycles1

0

0

11

5 μs + 5 ADCK cycles + 5 bus clock cycles

1. To achieve this time, CFG2[ADACKEN] must be 1 for at least 5 μs prior to the conversion is initiated.

Table 28-71. Average number factor (AverageNum)
SC3[AVGE]

SC3[AVGS]

Average number factor (AverageNum)

0

xx

1

1

00

4

1

01

8

1

10

16

1

11

32

Table 28-72. Base conversion time (BCT)
Mode

Base conversion time (BCT)

8b single-ended

17 ADCK cycles

9b differential

27 ADCK cycles

10b single-ended

20 ADCK cycles

11b differential

30 ADCK cycles

12b single-ended

20 ADCK cycles

13b differential

30 ADCK cycles

16b single-ended

25 ADCK cycles

16b differential

34 ADCK cycles

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Table 28-73. Long sample time adder (LSTAdder)
CFG1[ADLSMP]

CFG2[ADLSTS]

Long sample time adder
(LSTAdder)

0

xx

0 ADCK cycles

1

00

20 ADCK cycles

1

01

12 ADCK cycles

1

10

6 ADCK cycles

1

11

2 ADCK cycles

Table 28-74. High-speed conversion time adder (HSCAdder)
CFG2[ADHSC]

High-speed conversion time adder (HSCAdder)

0

0 ADCK cycles

1

2 ADCK cycles

Note
The ADCK frequency must be between fADCK minimum and
fADCK maximum to meet ADC specifications.

28.4.4.6 Conversion time examples
The following examples use the Figure 28-62, and the information provided in Table
28-70 through Table 28-74.
28.4.4.6.1 Typical conversion time configuration
A typical configuration for ADC conversion is:
• 10-bit mode, with the bus clock selected as the input clock source
• The input clock divide-by-1 ratio selected
• Bus frequency of 8 MHz
• Long sample time disabled
• High-speed conversion disabled
The conversion time for a single conversion is calculated by using the Figure 28-62, and
the information provided in Table 28-70 through Table 28-74. The table below lists the
variables of Figure 28-62.
Table 28-75. Typical conversion time
Variable

Time

SFCAdder

5 ADCK cycles + 5 bus clock cycles
Table continues on the next page...

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Table 28-75. Typical conversion time (continued)
Variable

Time

AverageNum

1

BCT

20 ADCK cycles

LSTAdder

0

HSCAdder

0

The resulting conversion time is generated using the parameters listed in the preceding
table. Therefore, for a bus clock and an ADCK frequency equal to 8 MHz, the resulting
conversion time is 3.75 µs.
28.4.4.6.2 Long conversion time configuration
A configuration for long ADC conversion is:
• 16-bit differential mode with the bus clock selected as the input clock source
• The input clock divide-by-8 ratio selected
• Bus frequency of 8 MHz
• Long sample time enabled
• Configured for longest adder
• High-speed conversion disabled
• Average enabled for 32 conversions
The conversion time for this conversion is calculated by using the Figure 28-62, and the
information provided in Table 28-70 through Table 28-74. The following table lists the
variables of the Figure 28-62.
Table 28-76. Typical conversion time
Variable

Time

SFCAdder

3 ADCK cycles + 5 bus clock cycles

AverageNum

32

BCT

34 ADCK cycles

LSTAdder

20 ADCK cycles

HSCAdder

0

The resulting conversion time is generated using the parameters listed in the preceding
table. Therefore, for bus clock equal to 8 MHz and ADCK equal to 1 MHz, the resulting
conversion time is 57.625 µs, that is, AverageNum. This results in a total conversion time
of 1.844 ms.
28.4.4.6.3 Short conversion time configuration
A configuration for short ADC conversion is:
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•
•
•
•
•

8-bit Single-Ended mode with the bus clock selected as the input clock source
The input clock divide-by-1 ratio selected
Bus frequency of 20 MHz
Long sample time disabled
High-speed conversion enabled

The conversion time for this conversion is calculated by using the Figure 28-62, and the
information provided in Table 28-70 through Table 28-74. The table below lists the
variables of Figure 28-62.
Table 28-77. Typical conversion time
Variable

Time

SFCAdder

5 ADCK cycles + 5 bus clock cycles

AverageNum

1

BCT

17 ADCK cycles

LSTAdder

0 ADCK cycles

HSCAdder

2

The resulting conversion time is generated using the parameters listed in in the preceding
table. Therefore, for bus clock and ADCK frequency equal to 20 MHz, the resulting
conversion time is 1.45 µs.

28.4.4.7 Hardware average function
The hardware average function can be enabled by setting SC3[AVGE]=1 to perform a
hardware average of multiple conversions. The number of conversions is determined by
the AVGS[1:0] bits, which can select 4, 8, 16, or 32 conversions to be averaged. While
the hardware average function is in progress, SC2[ADACT] will be set.
After the selected input is sampled and converted, the result is placed in an accumulator
from which an average is calculated once the selected number of conversions have been
completed. When hardware averaging is selected, the completion of a single conversion
will not set SC1n[COCO].
If the compare function is either disabled or evaluates true, after the selected number of
conversions are completed, the average conversion result is transferred into the data
result registers, Rn, and SC1n[COCO] is set. An ADC interrupt is generated upon the
setting of SC1n[COCO] if the respective ADC interrupt is enabled, that is,
SC1n[AIEN]=1.

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Note
The hardware average function can perform conversions on a
channel while the MCU is in Wait or Normal Stop modes. The
ADC interrupt wakes the MCU when the hardware average is
completed if SC1n[AIEN] was set.

28.4.5 Automatic compare function
The compare function can be configured to check whether the result is less than or
greater-than-or-equal-to a single compare value, or, if the result falls within or outside a
range determined by two compare values. The compare mode is determined by
SC2[ACFGT], SC2[ACREN], and the values in the compare value registers, CV1 and
CV2. After the input is sampled and converted, the compare values in CV1 and CV2 are
used as described in the following table. There are six Compare modes as shown in the
following table.
Table 28-78. Compare modes
SC2[AC
FGT]

SC2[AC
REN]

ADCCV1
relative to
ADCCV2

0

0

1

Function

Compare mode description

—

Less than threshold

Compare true if the result is less than the
CV1 registers.

0

—

Greater than or equal to threshold

Compare true if the result is greater than or
equal to CV1 registers.

0

1

Less than or
equal

Outside range, not inclusive

Compare true if the result is less than CV1
Or the result is greater than CV2.

0

1

Greater than

Inside range, not inclusive

Compare true if the result is less than CV1
And the result is greater than CV2.

1

1

Less than or
equal

Inside range, inclusive

Compare true if the result is greater than or
equal to CV1 And the result is less than or
equal to CV2.

1

1

Greater than

Outside range, inclusive

Compare true if the result is greater than or
equal to CV1 Or the result is less than or
equal to CV2.

With SC2[ACREN] =1, and if the value of CV1 is less than or equal to the value of CV2,
then setting SC2[ACFGT] will select a trigger-if-inside-compare-range inclusive-ofendpoints function. Clearing SC2[ACFGT] will select a trigger-if-outside-comparerange, not-inclusive-of-endpoints function.
If CV1 is greater than CV2, setting SC2[ACFGT] will select a trigger-if-outsidecompare-range, inclusive-of-endpoints function. Clearing SC2[ACFGT] will select a
trigger-if-inside-compare-range, not-inclusive-of-endpoints function.
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If the condition selected evaluates true, SC1n[COCO] is set.
Upon completion of a conversion while the compare function is enabled, if the compare
condition is not true, SC1n[COCO] is not set and the conversion result data will not be
transferred to the result register, Rn. If the hardware averaging function is enabled, the
compare function compares the averaged result to the compare values. The same compare
function definitions apply. An ADC interrupt is generated when SC1n[COCO] is set and
the respective ADC interrupt is enabled, that is, SC1n[AIEN]=1.
Note
The compare function can monitor the voltage on a channel
while the MCU is in Wait or Normal Stop modes. The ADC
interrupt wakes the MCU when the compare condition is met.

28.4.6 Calibration function
The ADC contains a self-calibration function that is required to achieve the specified
accuracy. Calibration must be run, or valid calibration values written, after any reset and
before a conversion is initiated. The calibration function sets the offset calibration value,
the minus-side calibration values, and the plus-side calibration values. The offset
calibration value is automatically stored in the ADC offset correction register (OFS), and
the plus-side and minus-side calibration values are automatically stored in the ADC plusside and minus-side calibration registers, CLPx and CLMx. The user must configure the
ADC correctly prior to calibration, and must generate the plus-side and minus-side gain
calibration results and store them in the ADC plus-side gain register (PG) after the
calibration function completes.
Prior to calibration, the user must configure the ADC's clock source and frequency, low
power configuration, voltage reference selection, sample time, and high speed
configuration according to the application's clock source availability and needs. If the
application uses the ADC in a wide variety of configurations, the configuration for which
the highest accuracy is required should be selected, or multiple calibrations can be done
for the different configurations. For best calibration results:
• Set hardware averaging to maximum, that is, SC3[AVGE]=1 and SC3[AVGS]=11
for an average of 32
• Set ADC clock frequency fADCK less than or equal to 4 MHz
• VREFH=VDDA
• Calibrate at nominal voltage and temperature
The input channel, conversion mode continuous function, compare function, resolution
mode, and differential/single-ended mode are all ignored during the calibration function.
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To initiate calibration, the user sets SC3[CAL] and the calibration will automatically
begin if the SC2[ADTRG] is 0. If SC2[ADTRG] is 1, SC3[CAL] will not get set and
SC3[CALF] will be set. While calibration is active, no ADC register can be written and
no stop mode may be entered, or the calibration routine will be aborted causing
SC3[CAL] to clear and SC3[CALF] to set. At the end of a calibration sequence,
SC1n[COCO] will be set. SC1n[AIEN] can be used to allow an interrupt to occur at the
end of a calibration sequence. At the end of the calibration routine, if SC3[CALF] is not
set, the automatic calibration routine is completed successfully.
To complete calibration, the user must generate the gain calibration values using the
following procedure:
1. Initialize or clear a 16-bit variable in RAM.
2. Add the plus-side calibration results CLP0, CLP1, CLP2, CLP3, CLP4, and CLPS to
the variable.
3. Divide the variable by two.
4. Set the MSB of the variable.
5. The previous two steps can be achieved by setting the carry bit, rotating to the right
through the carry bit on the high byte and again on the low byte.
6. Store the value in the plus-side gain calibration register PG.
7. Repeat the procedure for the minus-side gain calibration value.
When calibration is complete, the user may reconfigure and use the ADC as desired. A
second calibration may also be performed, if desired, by clearing and again setting
SC3[CAL].
Overall, the calibration routine may take as many as 14k ADCK cycles and 100 bus
cycles, depending on the results and the clock source chosen. For an 8 MHz clock source,
this length amounts to about 1.7 ms. To reduce this latency, the calibration values, which
are offset, plus-side and minus-side gain, and plus-side and minus-side calibration values,
may be stored in flash memory after an initial calibration and recovered prior to the first
ADC conversion. This method can reduce the calibration latency to 20 register store
operations on all subsequent power, reset, or Low-Power Stop mode recoveries.

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28.4.7 User-defined offset function
OFS contains the user-selected or calibration-generated offset error correction value. This
register is a 2’s complement, left-justified. The value in OFS is subtracted from the
conversion and the result is transferred into the result registers, Rn. If the result is greater
than the maximum or less than the minimum result value, it is forced to the appropriate
limit for the current mode of operation.
The formatting of the OFS is different from the data result register, Rn, to preserve the
resolution of the calibration value regardless of the conversion mode selected. Lower
order bits are ignored in lower resolution modes. For example, in 8-bit single-ended
mode, OFS[14:7] are subtracted from D[7:0]; OFS[15] indicates the sign (negative
numbers are effectively added to the result) and OFS[6:0] are ignored. The same bits are
used in 9-bit differential mode because OFS[15] indicates the sign bit, which maps to
D[8]. For 16-bit differential mode, OFS[15:0] are directly subtracted from the conversion
result data D[15:0]. In 16-bit single-ended mode, there is no field in the OFS
corresponding to the least significant result D[0], so odd values, such as -1 or +1, cannot
be subtracted from the result.
OFS is automatically set according to calibration requirements once the self-calibration
sequence is done, that is, SC3[CAL] is cleared. The user may write to OFS to override
the calibration result if desired. If the OFS is written by the user to a value that is
different from the calibration value, the ADC error specifications may not be met. Storing
the value generated by the calibration function in memory before overwriting with a userspecified value is recommended.
Note
There is an effective limit to the values of offset that can be set
by the user. If the magnitude of the offset is too high, the results
of the conversions will cap off at the limits.
The offset calibration function may be employed by the user to remove application
offsets or DC bias values. OFS may be written with a number in 2's complement format
and this offset will be subtracted from the result, or hardware averaged value. To add an
offset, store the negative offset in 2's complement format and the effect will be an
addition. An offset correction that results in an out-of-range value will be forced to the
minimum or maximum value. The minimum value for single-ended conversions is
0x0000; for a differential conversion it is 0x8000.
To preserve accuracy, the calibrated offset value initially stored in OFS must be added to
the user-defined offset. For applications that may change the offset repeatedly during
operation, store the initial offset calibration value in flash so it can be recovered and
added to any user offset adjustment value and the sum stored in OFS.
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28.4.8 Temperature sensor
The ADC module includes a temperature sensor whose output is connected to one of the
ADC analog channel inputs. The following equation provides an approximate transfer
function of the temperature sensor.
m
Figure 28-63. Approximate transfer function of the temperature sensor

where:
• VTEMP is the voltage of the temperature sensor channel at the ambient temperature.
• VTEMP25 is the voltage of the temperature sensor channel at 25 °C.
• m is referred as temperature sensor slope in the device data sheet. It is the hot or cold
voltage versus temperature slope in V/°C.
For temperature calculations, use the VTEMP25 and temperature sensor slope values from
the ADC Electricals table.
In application code, the user reads the temperature sensor channel, calculates VTEMP, and
compares to VTEMP25. If VTEMP is greater than VTEMP25 the cold slope value is applied in
the preceding equation. If VTEMP is less than VTEMP25, the hot slope value is applied in
the preceding equation. ADC Electricals table may only specify one temperature sensor
slope value. In that case, the user could use the same slope for the calculation across the
operational temperature range.
For more information on using the temperature sensor, see the application note titled
Temperature Sensor for the HCS08 Microcontroller Family (document AN3031).

28.4.9 MCU wait mode operation
Wait mode is a lower-power consumption Standby mode from which recovery is fast
because the clock sources remain active. If a conversion is in progress when the MCU
enters Wait mode, it continues until completion. Conversions can be initiated while the
MCU is in Wait mode by means of the hardware trigger or if continuous conversions are
enabled.

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The bus clock, bus clock divided by two, and ADACK are available as conversion clock
sources while in Wait mode. The use of ALTCLK as the conversion clock source in Wait
is dependent on the definition of ALTCLK for this MCU. See the Chip Configuration
information on ALTCLK specific to this MCU.
If the compare and hardware averaging functions are disabled, a conversion complete
event sets SC1n[COCO] and generates an ADC interrupt to wake the MCU from Wait
mode if the respective ADC interrupt is enabled, that is, when SC1n[AIEN]=1. If the
hardware averaging function is enabled, SC1n[COCO] will set, and generate an interrupt
if enabled, when the selected number of conversions are completed. If the compare
function is enabled, SC1n[COCO] will set, and generate an interrupt if enabled, only if
the compare conditions are met. If a single conversion is selected and the compare trigger
is not met, the ADC will return to its idle state and cannot wake the MCU from Wait
mode unless a new conversion is initiated by the hardware trigger.

28.4.10 MCU Normal Stop mode operation
Stop mode is a low-power consumption Standby mode during which most or all clock
sources on the MCU are disabled.

28.4.10.1 Normal Stop mode with ADACK disabled
If the asynchronous clock, ADACK, is not selected as the conversion clock, executing a
stop instruction aborts the current conversion and places the ADC in its Idle state. The
contents of the ADC registers, including Rn, are unaffected by Normal Stop mode. After
exiting from Normal Stop mode, a software or hardware trigger is required to resume
conversions.

28.4.10.2 Normal Stop mode with ADACK enabled
If ADACK is selected as the conversion clock, the ADC continues operation during
Normal Stop mode. See the chip configuration chapter for configuration information for
this MCU.
If a conversion is in progress when the MCU enters Normal Stop mode, it continues until
completion. Conversions can be initiated while the MCU is in Normal Stop mode by
means of the hardware trigger or if continuous conversions are enabled.

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If the compare and hardware averaging functions are disabled, a conversion complete
event sets SC1n[COCO] and generates an ADC interrupt to wake the MCU from Normal
Stop mode if the respective ADC interrupt is enabled, that is, when SC1n[AIEN]=1. The
result register, Rn, will contain the data from the first completed conversion that occurred
during Normal Stop mode. If the hardware averaging function is enabled, SC1n[COCO]
will set, and generate an interrupt if enabled, when the selected number of conversions
are completed. If the compare function is enabled, SC1n[COCO] will set, and generate an
interrupt if enabled, only if the compare conditions are met. If a single conversion is
selected and the compare is not true, the ADC will return to its Idle state and cannot wake
the MCU from Normal Stop mode unless a new conversion is initiated by another
hardware trigger.

28.4.11 MCU Low-Power Stop mode operation
The ADC module is automatically disabled when the MCU enters Low-Power Stop
mode. All module registers contain their reset values following exit from Low-Power
Stop mode. Therefore, the module must be re-enabled and re-configured following exit
from Low-Power Stop mode.
NOTE
For the chip specific modes of operation, see the power
management information for the device.

28.5 Initialization information
This section gives an example that provides some basic direction on how to initialize and
configure the ADC module. The user can configure the module for 16-bit, 12-bit, 10-bit,
or 8-bit single-ended resolution or 16-bit, 13-bit, 11-bit, or 9-bit differential resolution,
single or continuous conversion, and a polled or interrupt approach, among many other
options. For information used in this example, refer to Table 28-73, Table 28-74, and
Table 28-75.
Note
Hexadecimal values are designated by a preceding 0x, binary
values designated by a preceding %, and decimal values have
no preceding character.

28.5.1 ADC module initialization example
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28.5.1.1 Initialization sequence
Before the ADC module can be used to complete conversions, an initialization procedure
must be performed. A typical sequence is:
1. Calibrate the ADC by following the calibration instructions in Calibration function.
2. Update CFG to select the input clock source and the divide ratio used to generate
ADCK. This register is also used for selecting sample time and low-power
configuration.
3. Update SC2 to select the conversion trigger, hardware or software, and compare
function options, if enabled.
4. Update SC3 to select whether conversions will be continuous or completed only once
(ADCO) and whether to perform hardware averaging.
5. Update SC1:SC1n registers to select whether conversions will be single-ended or
differential and to enable or disable conversion complete interrupts. Also, select the
input channel which can be used to perform conversions.

28.5.1.2 Pseudo-code example
In this example, the ADC module is set up with interrupts enabled to perform a single 10bit conversion at low-power with a long sample time on input channel 1, where ADCK is
derived from the bus clock divided by 1.
CFG1 = 0x98 (%10011000)
Bit 7
ADLPC
1
Bit 6:5 ADIV
00
Bit 4
ADLSMP 1
Bit 3:2
MODE
10
bit conversion.
Bit 1:0
ADICLK
00

Configures for low power, lowers maximum clock speed.
Sets the ADCK to the input clock ÷ 1.
Configures for long sample time.
Selects the single-ended 10-bit conversion, differential 11Selects the bus clock.

SC2 = 0x00 (%00000000)
Bit
Bit
Bit
Bit
Bit
Bit
Bit
and VREFL).

7
6
5
4
3
2
1:0

ADACT
ADTRG
ACFE
ACFGT
ACREN
DMAEN
REFSEL

0
0
0
0
0
0
00

Flag indicates if a conversion is in progress.
Software trigger selected.
Compare function disabled.
Not used in this example.
Compare range disabled.
DMA request disabled.
Selects default voltage reference pin pair (External pins VREFH

SC1A = 0x41 (%01000001)
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Bit
Bit
Bit
Bit

7
6
5
4:0

COCO
AIEN
DIFF
ADCH

0
1
0
00001

Read-only flag which is set when a conversion completes.
Conversion complete interrupt enabled.
Single-ended conversion selected.
Input channel 1 selected as ADC input channel.

RA = 0xxx
Holds results of conversion.

CV = 0xxx
Holds compare value when compare function enabled.
Reset

Initialize ADC
CFG1 = 0x98
SC2 = 0x00
SC1n = 0x41

Check
No
SC1n[COCO]=1?
Yes

Read Rn
to clear
SC1n[COCO]

Continue

Figure 28-64. Initialization flowchart example

28.6 Application information
The ADC has been designed to be integrated into a microcontroller for use in embedded
control applications requiring an ADC.

28.6.1 External pins and routing

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28.6.1.1 Analog supply pins
Depending on the device, the analog power and ground supplies, VDDA and VSSA, of the
ADC module are available as:
• VDDA and VSSA available as separate pins—When available on a separate pin, both
VDDA and VSSA must be connected to the same voltage potential as their
corresponding MCU digital supply, VDD and VSS, and must be routed carefully for
maximum noise immunity and bypass capacitors placed as near as possible to the
package.
• VSSA is shared on the same pin as the MCU digital VSS.
• VSSA and VDDA are shared with the MCU digital supply pins—In these cases, there
are separate pads for the analog supplies bonded to the same pin as the corresponding
digital supply so that some degree of isolation between the supplies is maintained.
If separate power supplies are used for analog and digital power, the ground connection
between these supplies must be at the VSSA pin. This must be the only ground connection
between these supplies, if possible. VSSA makes a good single point ground location.

28.6.1.2 Analog voltage reference pins
In addition to the analog supplies, the ADC module has connections for two reference
voltage inputs used by the converter:
• VREFSH is the high reference voltage for the converter.
• VREFSL is the low reference voltage for the converter.
The ADC can be configured to accept one of two voltage reference pairs for VREFSH and
VREFSL. Each pair contains a positive reference and a ground reference. The two pairs are
external, VREFH and VREFL and alternate, VALTH and VALTL. These voltage references are
selected using SC2[REFSEL]. The alternate voltage reference pair, VALTH and VALTL,
may select additional external pins or internal sources based on MCU configuration. See
the chip configuration information on the voltage references specific to this MCU.
In some packages, the external or alternate pairs are connected in the package to VDDA
and VSSA, respectively. One of these positive references may be shared on the same pin
as VDDA on some devices. One of these ground references may be shared on the same pin
as VSSA on some devices.
If externally available, the positive reference may be connected to the same potential as
VDDA or may be driven by an external source to a level between the minimum Ref
Voltage High and the VDDA potential. The positive reference must never exceed VDDA. If
externally available, the ground reference must be connected to the same voltage
potential as VSSA. The voltage reference pairs must be routed carefully for maximum
noise immunity and bypass capacitors placed as near as possible to the package.
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AC current in the form of current spikes required to supply charge to the capacitor array
at each successive approximation step is drawn through the VREFH and VREFL loop. The
best external component to meet this current demand is a 0.1 μF capacitor with good
high-frequency characteristics. This capacitor is connected between VREFH and VREFL
and must be placed as near as possible to the package pins. Resistance in the path is not
recommended because the current causes a voltage drop that could result in conversion
errors. Inductance in this path must be minimum, that is, parasitic only.

28.6.1.3 Analog input pins
The external analog inputs are typically shared with digital I/O pins on MCU devices.
Empirical data shows that capacitors on the analog inputs improve performance in the
presence of noise or when the source impedance is high. Use of 0.01 μF capacitors with
good high-frequency characteristics is sufficient. These capacitors are not necessary in all
cases, but when used, they must be placed as near as possible to the package pins and be
referenced to VSSA.
For proper conversion, the input voltage must fall between VREFH and VREFL. If the input
is equal to or exceeds VREFH, the converter circuit converts the signal to 0xFFF, which is
full scale 12-bit representation, 0x3FF, which is full scale 10-bit representation, or 0xFF,
which is full scale 8-bit representation. If the input is equal to or less than VREFL, the
converter circuit converts it to 0x000. Input voltages between VREFH and VREFL are
straight-line linear conversions. There is a brief current associated with VREFL when the
sampling capacitor is charging.
For minimal loss of accuracy due to current injection, pins adjacent to the analog input
pins must not be transitioning during conversions.

28.6.2 Sources of error

28.6.2.1 Sampling error
For proper conversions, the input must be sampled long enough to achieve the proper
accuracy.

RAS + RADIN =SC / (FMAX * NUMTAU * CADIN)
Figure 28-65. Sampling equation

Where:
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RAS = External analog source resistance
SC = Number of ADCK cycles used during sample window
CADIN = Internal ADC input capacitance
NUMTAU = -ln(LSBERR / 2N)
LSBERR = value of acceptable sampling error in LSBs
N = 8 in 8-bit mode, 10 in 10-bit mode, 12 in 12-bit mode or 16 in 16-bit mode
Higher source resistances or higher-accuracy sampling is possible by setting
CFG1[ADLSMP] and changing CFG2[ADLSTS] to increase the sample window, or
decreasing ADCK frequency to increase sample time.

28.6.2.2 Pin leakage error
Leakage on the I/O pins can cause conversion error if the external analog source
resistance, RAS, is high. If this error cannot be tolerated by the application, keep RAS
lower than VREFH / (4 × ILEAK × 2N) for less than 1/4 LSB leakage error, where N = 8 in
8-bit mode, 10 in 10-bit mode, 12 in 12-bit mode, or 16 in 16-bit mode.

28.6.2.3 Noise-induced errors
System noise that occurs during the sample or conversion process can affect the accuracy
of the conversion. The ADC accuracy numbers are guaranteed as specified only if the
following conditions are met:
• There is a 0.1 μF low-ESR capacitor from VREFH to VREFL.
• There is a 0.1 μF low-ESR capacitor from VDDA to VSSA.
• If inductive isolation is used from the primary supply, an additional 1 μF capacitor is
placed from VDDA to VSSA.
• VSSA, and VREFL, if connected, is connected to VSS at a quiet point in the ground
plane.
• Operate the MCU in Wait or Normal Stop mode before initiating (hardware-triggered
conversions) or immediately after initiating (hardware- or software-triggered
conversions) the ADC conversion.

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• For software triggered conversions, immediately follow the write to SC1 with a
Wait instruction or Stop instruction.
• For Normal Stop mode operation, select ADACK as the clock source. Operation
in Normal Stop reduces VDD noise but increases effective conversion time due to
stop recovery.
• There is no I/O switching, input or output, on the MCU during the conversion.
There are some situations where external system activity causes radiated or conducted
noise emissions or excessive VDD noise is coupled into the ADC. In these situations, or
when the MCU cannot be placed in Wait or Normal Stop mode, or I/O activity cannot be
halted, the following actions may reduce the effect of noise on the accuracy:
• Place a 0.01 μF capacitor (CAS) on the selected input channel to VREFL or VSSA. This
improves noise issues, but affects the sample rate based on the external analog source
resistance.
• Average the result by converting the analog input many times in succession and
dividing the sum of the results. Four samples are required to eliminate the effect of a
1 LSB, one-time error.
• Reduce the effect of synchronous noise by operating off the asynchronous clock, that
is, ADACK, and averaging. Noise that is synchronous to ADCK cannot be averaged
out.

28.6.2.4 Code width and quantization error
The ADC quantizes the ideal straight-line transfer function into 65536 steps in the 16-bit
mode). Each step ideally has the same height, that is, 1 code, and width. The width is
defined as the delta between the transition points to one code and the next. The ideal code
width for an N-bit converter, where N can be 16, 12, 10, or 8, defined as 1 LSB, is:

LSB
Figure 28-66. Ideal code width for an N-bit converter

There is an inherent quantization error due to the digitization of the result. For 8-bit, 10bit, or 12-bit conversions, the code transitions when the voltage is at the midpoint
between the points where the straight line transfer function is exactly represented by the
actual transfer function. Therefore, the quantization error will be ± 1/2 LSB in 8-bit, 10bit, or 12-bit modes. As a consequence, however, the code width of the first (0x000)
conversion is only 1/2 LSB and the code width of the last (0xFF or 0x3FF) is 1.5 LSB.
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For 16-bit conversions, the code transitions only after the full code width is present, so
the quantization error is -1 LSB to 0 LSB and the code width of each step is 1 LSB.

28.6.2.5 Linearity errors
The ADC may also exhibit non-linearity of several forms. Every effort has been made to
reduce these errors, but the system designers must be aware of these errors because they
affect overall accuracy:
• Zero-scale error (EZS), sometimes called offset: This error is defined as the difference
between the actual code width of the first conversion and the ideal code width. This
is 1/2 LSB in 8-bit, 10-bit, or 12-bit modes and 1 LSB in 16-bit mode. If the first
conversion is 0x001, the difference between the actual 0x001 code width and its ideal
(1 LSB) is used.
• Full-scale error (EFS): This error is defined as the difference between the actual code
width of the last conversion and the ideal code width. This is 1.5 LSB in 8-bit, 10-bit,
or 12-bit modes and 1 LSB in 16-bit mode. If the last conversion is 0x3FE, the
difference between the actual 0x3FE code width and its ideal (1 LSB) is used.
• Differential non-linearity (DNL): This error is defined as the worst-case difference
between the actual code width and the ideal code width for all conversions.
• Integral non-linearity (INL): This error is defined as the highest-value or absolute
value that the running sum of DNL achieves. More simply, this is the worst-case
difference of the actual transition voltage to a given code and its corresponding ideal
transition voltage, for all codes.
• Total unadjusted error (TUE): This error is defined as the difference between the
actual transfer function and the ideal straight-line transfer function and includes all
forms of error.

28.6.2.6 Code jitter, non-monotonicity, and missing codes
Analog-to-digital converters are susceptible to three special forms of error:
• Code jitter: Code jitter is when, at certain points, a given input voltage converts to
one of the two values when sampled repeatedly. Ideally, when the input voltage is
infinitesimally smaller than the transition voltage, the converter yields the lower
code, and vice-versa. However, even small amounts of system noise can cause the
converter to be indeterminate, between two codes, for a range of input voltages
around the transition voltage.
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This error may be reduced by repeatedly sampling the input and averaging the result.
Additionally, the techniques discussed in Noise-induced errors reduces this error.
• Non-monotonicity: Non-monotonicity is defined as when, except for code jitter, the
converter converts to a lower code for a higher input voltage.
• Missing codes: Missing codes are those values never converted for any input value.
In 8-bit or 10-bit mode, the ADC is guaranteed to be monotonic and have no missing
codes.

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Chapter 29
Comparator (CMP)
29.1 Introduction
NOTE
For the chip-specific implementation details of this module's
instances see the chip configuration information.
The comparator (CMP) module provides a circuit for comparing two analog input
voltages. The comparator circuit is designed to operate across the full range of the supply
voltage, known as rail-to-rail operation.
The Analog MUX (ANMUX) provides a circuit for selecting an analog input signal from
eight channels. One signal is provided by the 6-bit digital-to-analog converter (DAC).
The mux circuit is designed to operate across the full range of the supply voltage.
The 6-bit DAC is 64-tap resistor ladder network which provides a selectable voltage
reference for applications where voltage reference is needed. The 64-tap resistor ladder
network divides the supply reference Vin into 64 voltage levels. A 6-bit digital signal
input selects the output voltage level, which varies from Vin to Vin/64. Vin can be selected
from two voltage sources, Vin1 and Vin2. The 6-bit DAC from a comparator is available
as an on-chip internal signal only and is not available externally to a pin.

29.2 CMP features
The CMP has the following features:
• Operational over the entire supply range
• Inputs may range from rail to rail
• Programmable hysteresis control

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• Selectable interrupt on rising-edge, falling-edge, or both rising or falling edges of the
comparator output
• Selectable inversion on comparator output
• Capability to produce a wide range of outputs such as:
• Sampled
• Windowed, which is ideal for certain PWM zero-crossing-detection applications
• Digitally filtered:
• Filter can be bypassed
• Can be clocked via external SAMPLE signal or scaled bus clock
• External hysteresis can be used at the same time that the output filter is used for
internal functions
• Two software selectable performance levels:
• Shorter propagation delay at the expense of higher power
• Low power, with longer propagation delay
• DMA transfer support
• A comparison event can be selected to trigger a DMA transfer
• Functional in all modes of operation
• The window and filter functions are not available in the following modes:
• Stop
• VLPS
• LLS
• VLLSx

29.3 6-bit DAC key features
•
•
•
•

6-bit resolution
Selectable supply reference source
Power Down mode to conserve power when not in use
Option to route the output to internal comparator input

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Chapter 29 Comparator (CMP)

29.4 ANMUX key features
• Two 8-to-1 channel mux

• Operational over the entire supply range

29.5 CMP, DAC and ANMUX diagram
The following figure shows the block diagram for the High-Speed Comparator, DAC,
and ANMUX modules.

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CMP block diagram

VRSEL
Vin1

Vin2

VOSEL[5:0]
MUX

DAC output

MUX

64-level

DACEN

DAC

PSEL[2:0]

CMP
MUX

Reference Input 0
Reference Input 1
Reference Input 2
Reference Input 3
Reference Input 4
Reference Input 5
Reference Input 6

INP
Sample input

CMP

MUX

ANMUX

Window
and filter
control

INM

IRQ

CMPO

MSEL[2:0]

Figure 29-1. CMP, DAC and ANMUX block diagram

29.6 CMP block diagram
The following figure shows the block diagram for the CMP module.

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Chapter 29 Comparator (CMP)
Internal bus

FILT_PER
EN,PMODE,HYSCTRL[1:0] COS
INV

OPE
WE

FILTER_CNT SE COUT

IER/F

CFR/F

INP

+

-

CMPO

Polarity
select

Window
control

Interrupt
control

Filter
block

INM

IRQ

COUT

To other SOC functions
WINDOW/SAMPLE

bus clock

Clock
prescaler

FILT_PER

1

0

0
divided
bus
clock

COUTA
CGMUX

SE

1

CMPO to
PAD

COS

Figure 29-2. Comparator module block diagram

In the CMP block diagram:
• The Window Control block is bypassed when CR1[WE] = 0
• If CR1[WE] = 1, the comparator output will be sampled on every bus clock when
WINDOW=1 to generate COUTA. Sampling does NOT occur when WINDOW = 0.
• The Filter block is bypassed when not in use.
• The Filter block acts as a simple sampler if the filter is bypassed and
CR0[FILTER_CNT] is set to 0x01.
• The Filter block filters based on multiple samples when the filter is bypassed and
CR0[FILTER_CNT] is set greater than 0x01.
• If CR1[SE] = 1, the external SAMPLE input is used as sampling clock
• IF CR1[SE] = 0, the divided bus clock is used as sampling clock

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• If enabled, the Filter block will incur up to one bus clock additional latency penalty
on COUT due to the fact that COUT, which is crossing clock domain boundaries,
must be resynchronized to the bus clock.
• CR1[WE] and CR1[SE] are mutually exclusive.

29.7 Memory map/register definitions
CMP memory map
Absolute
address
(hex)

Width
Access
(in bits)

Register name

Reset value

Section/
page

4007_3000

CMP Control Register 0 (CMP0_CR0)

8

R/W

00h

29.7.1/514

4007_3001

CMP Control Register 1 (CMP0_CR1)

8

R/W

00h

29.7.2/515

4007_3002

CMP Filter Period Register (CMP0_FPR)

8

R/W

00h

29.7.3/517

4007_3003

CMP Status and Control Register (CMP0_SCR)

8

R/W

00h

29.7.4/517

4007_3004

DAC Control Register (CMP0_DACCR)

8

R/W

00h

29.7.5/518

4007_3005

MUX Control Register (CMP0_MUXCR)

8

R/W

00h

29.7.6/519

1

0

29.7.1 CMP Control Register 0 (CMPx_CR0)
Address: 4007_3000h base + 0h offset = 4007_3000h
Bit

7

Read
Write
Reset

0
0

6

5

4

FILTER_CNT
0

0

0

3

2

0

0

0

0

HYSTCTR
0

0

CMPx_CR0 field descriptions
Field
7
Reserved
6–4
FILTER_CNT

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
Filter Sample Count
Represents the number of consecutive samples that must agree prior to the comparator ouput filter
accepting a new output state. For information regarding filter programming and latency, see the Functional
description.
000
001
010
011
100

Filter is disabled. If SE = 1, then COUT is a logic 0. This is not a legal state, and is not
recommended. If SE = 0, COUT = COUTA.
One sample must agree. The comparator output is simply sampled.
2 consecutive samples must agree.
3 consecutive samples must agree.
4 consecutive samples must agree.
Table continues on the next page...

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CMPx_CR0 field descriptions (continued)
Field

Description
101
110
111

5 consecutive samples must agree.
6 consecutive samples must agree.
7 consecutive samples must agree.

3
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

2
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

1–0
HYSTCTR

Comparator hard block hysteresis control
Defines the programmable hysteresis level. The hysteresis values associated with each level are devicespecific. See the Data Sheet of the device for the exact values.
00
01
10
11

Level 0
Level 1
Level 2
Level 3

29.7.2 CMP Control Register 1 (CMPx_CR1)
Address: 4007_3000h base + 1h offset = 4007_3001h
Bit

Read
Write
Reset

7

6

5

4

3

2

1

0

SE

WE

TRIGM

PMODE

INV

COS

OPE

EN

0

0

0

0

0

0

0

0

CMPx_CR1 field descriptions
Field
7
SE

Description
Sample Enable
At any given time, either SE or WE can be set. It is mandatory request to not set SE and WE both at a
given time.
0
1

6
WE

Windowing Enable
At any given time, either SE or WE can be set. It is mandatory request to not set SE and WE both at a
given time.
0
1

5
TRIGM

Sampling mode is not selected.
Sampling mode is selected.

Windowing mode is not selected.
Windowing mode is selected.

Trigger Mode Enable
CMP and DAC are configured to CMP Trigger mode when CMP_CR1[TRIGM] is set to 1. In addition, the
CMP should be enabled. If the DAC is to be used as a reference to the CMP, it should also be enabled.
Table continues on the next page...

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CMPx_CR1 field descriptions (continued)
Field

Description
CMP Trigger mode depends on an external timer resource to periodically enable the CMP and 6-bit DAC
in order to generate a triggered compare.
Upon setting TRIGM, the CMP and DAC are placed in a standby state until an external timer resource
trigger is received.
See the chip configuration chapter for details about the external timer resource.
0
1

4
PMODE

Power Mode Select
See the electrical specifications table in the device Data Sheet for details.
0
1

3
INV

Trigger mode is disabled.
Trigger mode is enabled.

Low-Speed (LS) Comparison mode selected. In this mode, CMP has slower output propagation delay
and lower current consumption.
High-Speed (HS) Comparison mode selected. In this mode, CMP has faster output propagation delay
and higher current consumption.

Comparator INVERT
Allows selection of the polarity of the analog comparator function. It is also driven to the COUT output, on
both the device pin and as SCR[COUT], when OPE=0.
0
1

Does not invert the comparator output.
Inverts the comparator output.

2
COS

Comparator Output Select

1
OPE

Comparator Output Pin Enable

0
1

0
1

Set the filtered comparator output (CMPO) to equal COUT.
Set the unfiltered comparator output (CMPO) to equal COUTA.

CMPO is not available on the associated CMPO output pin. If the comparator does not own the pin,
this field has no effect.
CMPO is available on the associated CMPO output pin.
The comparator output (CMPO) is driven out on the associated CMPO output pin if the comparator
owns the pin. If the comparator does not own the field, this bit has no effect.

0
EN

Comparator Module Enable
Enables the Analog Comparator module. When the module is not enabled, it remains in the off state, and
consumes no power. When the user selects the same input from analog mux to the positive and negative
port, the comparator is disabled automatically.
0
1

Analog Comparator is disabled.
Analog Comparator is enabled.

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29.7.3 CMP Filter Period Register (CMPx_FPR)
Address: 4007_3000h base + 2h offset = 4007_3002h
Bit

Read
Write
Reset

7

6

5

4

3

2

1

0

0

0

0

0

FILT_PER
0

0

0

0

CMPx_FPR field descriptions
Field
7–0
FILT_PER

Description
Filter Sample Period
Specifies the sampling period, in bus clock cycles, of the comparator output filter, when CR1[SE]=0.
Setting FILT_PER to 0x0 disables the filter. Filter programming and latency details appear in the
Functional description.
This field has no effect when CR1[SE]=1. In that case, the external SAMPLE signal is used to determine
the sampling period.

29.7.4 CMP Status and Control Register (CMPx_SCR)
Address: 4007_3000h base + 3h offset = 4007_3003h
Bit

7

Read

0

6

DMAEN

Write
Reset

0

0

5

0

0

4

3

IER

IEF

0

0

2

1

0

CFR

CFF

COUT

w1c

w1c

0

0

0

CMPx_SCR field descriptions
Field
7
Reserved
6
DMAEN

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
DMA Enable Control
Enables the DMA transfer triggered from the CMP module. When this field is set, a DMA request is
asserted when CFR or CFF is set.
0
1

5
Reserved
4
IER

DMA is disabled.
DMA is enabled.

This field is reserved.
This read-only field is reserved and always has the value 0.
Comparator Interrupt Enable Rising
Enables the CFR interrupt from the CMP. When this field is set, an interrupt will be asserted when CFR is
set.
Table continues on the next page...

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CMPx_SCR field descriptions (continued)
Field

Description
0
1

3
IEF

Comparator Interrupt Enable Falling
Enables the CFF interrupt from the CMP. When this field is set, an interrupt will be asserted when CFF is
set.
0
1

2
CFR

Detects a rising-edge on COUT, when set, during normal operation. CFR is cleared by writing 1 to it.
During Stop modes, CFR is level sensitive .
Rising-edge on COUT has not been detected.
Rising-edge on COUT has occurred.

Analog Comparator Flag Falling
Detects a falling-edge on COUT, when set, during normal operation. CFF is cleared by writing 1 to it.
During Stop modes, CFF is level senstive .
0
1

0
COUT

Interrupt is disabled.
Interrupt is enabled.

Analog Comparator Flag Rising

0
1
1
CFF

Interrupt is disabled.
Interrupt is enabled.

Falling-edge on COUT has not been detected.
Falling-edge on COUT has occurred.

Analog Comparator Output
Returns the current value of the Analog Comparator output, when read. The field is reset to 0 and will read
as CR1[INV] when the Analog Comparator module is disabled, that is, when CR1[EN] = 0. Writes to this
field are ignored.

29.7.5 DAC Control Register (CMPx_DACCR)
Address: 4007_3000h base + 4h offset = 4007_3004h
Bit

Read
Write
Reset

7

6

DACEN

VRSEL

0

0

5

4

3

2

1

0

0

0

0

VOSEL
0

0

0

CMPx_DACCR field descriptions
Field
7
DACEN

Description
DAC Enable
Enables the DAC. When the DAC is disabled, it is powered down to conserve power.
0
1

6
VRSEL

DAC is disabled.
DAC is enabled.

Supply Voltage Reference Source Select
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CMPx_DACCR field descriptions (continued)
Field

Description
0
1

5–0
VOSEL

V is selected as resistor ladder network supply reference V. in1in
V is selected as resistor ladder network supply reference V. in2in

DAC Output Voltage Select
Selects an output voltage from one of 64 distinct levels.
DACO = (V

in

/64) * (VOSEL[5:0] + 1) , so the DACO range is from V in /64 to V in .

29.7.6 MUX Control Register (CMPx_MUXCR)
Address: 4007_3000h base + 5h offset = 4007_3005h
Bit

Read
Write
Reset

7

6

PSTM

0

0

0

5

4

3

2

PSEL
0

0

1

0

MSEL
0

0

0

0

CMPx_MUXCR field descriptions
Field
7
PSTM

Description
Pass Through Mode Enable
This bit is used to enable to MUX pass through mode. Pass through mode is always available but for
some devices this feature must be always disabled due to the lack of package pins.
0
1

6
Reserved
5–3
PSEL

Pass Through Mode is disabled.
Pass Through Mode is enabled.

This field is reserved.
This read-only field is reserved and always has the value 0.
Plus Input Mux Control
Determines which input is selected for the plus input of the comparator. For INx inputs, see CMP, DAC,
and ANMUX block diagrams.
NOTE: When an inappropriate operation selects the same input for both muxes, the comparator
automatically shuts down to prevent itself from becoming a noise generator.
000
001
010
011
100
101
110
111

2–0
MSEL

IN0
IN1
IN2
IN3
IN4
IN5
IN6
IN7

Minus Input Mux Control
Determines which input is selected for the minus input of the comparator. For INx inputs, see CMP, DAC,
and ANMUX block diagrams.
Table continues on the next page...

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CMPx_MUXCR field descriptions (continued)
Field

Description
NOTE: When an inappropriate operation selects the same input for both muxes, the comparator
automatically shuts down to prevent itself from becoming a noise generator.
000
001
010
011
100
101
110
111

IN0
IN1
IN2
IN3
IN4
IN5
IN6
IN7

29.8 Functional description
The CMP module can be used to compare two analog input voltages applied to INP and
INM. CMPO is high when the non-inverting input is greater than the inverting input, and
is low when the non-inverting input is less than the inverting input. This signal can be
selectively inverted by setting CR1[INV] = 1.
SCR[IER] and SCR[IEF] are used to select the condition which will cause the CMP
module to assert an interrupt to the processor. SCR[CFF] is set on a falling-edge and
SCR[CFR] is set on rising-edge of the comparator output. The optionally filtered CMPO
can be read directly through SCR[COUT].

29.8.1 CMP functional modes
There are three main sub-blocks to the CMP module:
• The comparator itself
• The window function
• The filter function
The filter, CR0[FILTER_CNT], can be clocked from an internal or external clock source.
The filter is programmable with respect to the number of samples that must agree before
a change in the output is registered. In the simplest case, only one sample must agree. In
this case, the filter acts as a simple sampler.
The external sample input is enabled using CR1[SE]. When set, the output of the
comparator is sampled only on rising edges of the sample input.

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Chapter 29 Comparator (CMP)

The "windowing mode" is enabled by setting CR1[WE]. When set, the comparator output
is sampled only when WINDOW=1. This feature can be used to ignore the comparator
output during time periods in which the input voltages are not valid. This is especially
useful when implementing zero-crossing-detection for certain PWM applications.
The comparator filter and sampling features can be combined as shown in the following
table. Individual modes are discussed below.
Table 29-15. Comparator sample/filter controls
Mode #

CR1[EN]

CR1[WE]

CR1[SE]

CR0[FILTER_C
NT]

FPR[FILT_PER]

Operation

1

0

X

X

X

X

Disabled

2A

1

0

0

0x00

X

Continuous Mode

2B

1

0

0

X

0x00

See the Continuous mode (#s 2A &
2B).

3A

1

0

1

0x01

X

Sampled, Non-Filtered mode

3B

1

0

0

0x01

> 0x00

See the Sampled, Non-Filtered
mode (#s 3A & 3B).

4A

1

0

1

> 0x01

X

Sampled, Filtered mode

4B

1

0

0

> 0x01

> 0x00

See the Sampled, Filtered mode (#s
4A & 4B).

5A

1

1

0

0x00

X

Windowed mode

5B

1

1

0

X

0x00

Comparator output is sampled on
every rising bus clock edge when
SAMPLE=1 to generate COUTA.

See the Disabled mode (# 1).

See the Windowed mode (#s 5A &
5B).
6

1

1

0

0x01

0x01–0xFF

Windowed/Resampled mode
Comparator output is sampled on
every rising bus clock edge when
SAMPLE=1 to generate COUTA,
which is then resampled on an
interval determined by FILT_PER to
generate COUT.
See the Windowed/Resampled
mode (# 6).

7

1

1

0

> 0x01

0x01–0xFF

Windowed/Filtered mode
Comparator output is sampled on
every rising bus clock edge when
SAMPLE=1 to generate COUTA,
which is then resampled and filtered
to generate COUT.
See the Windowed/Filtered mode
(#7).

All other combinations of CR1[EN], CR1[WE], CR1[SE], CR0[FILTER_CNT], and FPR[FILT_PER] are illegal.

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Functional description

For cases where a comparator is used to drive a fault input, for example, for a motorcontrol module such as FTM, it must be configured to operate in Continuous mode so
that an external fault can immediately pass through the comparator to the target fault
circuitry.
Note
Filtering and sampling settings must be changed only after
setting CR1[SE]=0 and CR0[FILTER_CNT]=0x00. This resets
the filter to a known state.

29.8.1.1 Disabled mode (# 1)
In Disabled mode, the analog comparator is non-functional and consumes no power.
CMPO is 0 in this mode.

29.8.1.2 Continuous mode (#s 2A & 2B)
Internal bus

EN,PMODE,HYSTCTR[1:0]

FILT_PER
INV
COS

WE

OPE

FILTER_CNT SE COUT

IER/F

CFR/F

0
INP

+

-

CMPO

Polarity
select

Window
control

INM

Filter
block

Interrupt
control

IRQ

COUT
To other system functions
WINDOW/SAMPLE

bus clock
FILT_PER

Clock
prescaler

1

0

0
divided
bus
clock

COUTA
CGMUX

SE

1

CMPO to
PAD

COS

Figure 29-15. Comparator operation in Continuous mode

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Chapter 29 Comparator (CMP)

NOTE
See the chip configuration section for the source of sample/
window input.
The analog comparator block is powered and active. CMPO may be optionally inverted,
but is not subject to external sampling or filtering. Both window control and filter blocks
are completely bypassed. SCR[COUT] is updated continuously. The path from
comparator input pins to output pin is operating in combinational unclocked mode.
COUT and COUTA are identical.
For control configurations which result in disabling the filter block, see the Filter Block
Bypass Logic diagram.

29.8.1.3 Sampled, Non-Filtered mode (#s 3A & 3B)
Internal bus

EN,PMODE,HYSTCTR[1:0]

FILT_PER
INV
COS

OPE
WE

FILTER_CNT SE COUT

0x01

0

IER/F

CFR/F

1

INP

+
-

CMPO

Polarity
select

Window
control

INM

Filter
block

Interrupt
control

IRQ

COUT

To other SOC functions
WINDOW/SAMPLE

Clock
prescaler

bus clock
FILT_PER

1

0

0
divided
bus
clock

COUTA
CGMUX

SE=1

1

CMPO to
PAD

COS

Figure 29-16. Sampled, Non-Filtered (# 3A): sampling point externally driven

In Sampled, Non-Filtered mode, the analog comparator block is powered and active. The
path from analog inputs to COUTA is combinational unclocked. Windowing control is
completely bypassed. COUTA is sampled whenever a rising-edge is detected on the filter
block clock input.
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Functional description

The only difference in operation between Sampled, Non-Filtered (# 3A) and Sampled,
Non-Filtered (# 3B) is in how the clock to the filter block is derived. In #3A, the clock to
filter block is externally derived while in #3B, the clock to filter block is internally
derived.
The comparator filter has no other function than sample/hold of the comparator output in
this mode (# 3B).
Internal bus

EN,PMODE,HYSTCTR[1:0]

FILT_PER
INV
COS

OPE
WE

FILTER_CNT SE COUT

0

IER/F

CFR/F

0

0x01

INP

+

-

CMPO

Polarity
select

Window
control

Filter
block

INM

Interrupt
control

IRQ

COUT

WINDOW/SAMPLE

bus clock
FILT_PER

Clock
prescaler

To other SOC functions

1

0

0
divided bus clock

COUTA
CGMUX

SE=0

1

CMPO to
PAD

COS

Figure 29-17. Sampled, Non-Filtered (# 3B): sampling interval internally derived

29.8.1.4 Sampled, Filtered mode (#s 4A & 4B)
In Sampled, Filtered mode, the analog comparator block is powered and active. The path
from analog inputs to COUTA is combinational unclocked. Windowing control is
completely bypassed. COUTA is sampled whenever a rising edge is detected on the filter
block clock input.
The only difference in operation between Sampled, Non-Filtered (# 3A) and Sampled,
Filtered (# 4A) is that, now, CR0[FILTER_CNT]>1, which activates filter operation.

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Chapter 29 Comparator (CMP)
Internal bus

EN, PMODE, HYSTCTR[1:0]

FILT_PER
INV
COS

OPE
WE

FILTER_CNT SE COUT

> 0x01

0
INP

+
-

CMPO

Polarity
select

Window
control

INM

IER/F

CFR/F

1

Interrupt
control

Filter
block

IRQ

COUT
To other SOC functions
WINDOW/SAMPLE

bus clock

Clock
prescaler

FILT_PER

1

0

0
divided
bus
clock

COUTA
CGMUX

SE=1

1

CMPO to
PAD

COS

Figure 29-18. Sampled, Filtered (# 4A): sampling point externally driven

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Functional description
Internal bus

OPE

FILT_PER
EN, PMODE,HYSTCTR[1:0] COS

INV

WE

FILTER_CNT SE COUT

IER/F

CFR/F

>0x01
0

0

INP

+
-

Polarity
CMPO select

Window
control

INM

Filter
block

Interrupt
control

IRQ

COUT

WINDOW/SAMPLE

bus clock
FILT_PER

Clock
prescaler

To other SOC functions

1

0

0
divided
bus
clock

COUTA
CGMUX

SE=0

1

CMPO to
PAD

COS

Figure 29-19. Sampled, Filtered (# 4B): sampling point internally derived

The only difference in operation between Sampled, Non-Filtered (# 3B) and Sampled,
Filtered (# 4B) is that now, CR0[FILTER_CNT]>1, which activates filter operation.

29.8.1.5 Windowed mode (#s 5A & 5B)
The following figure illustrates comparator operation in the Windowed mode, ignoring
latency of the analog comparator, polarity select, and window control block. It also
assumes that the polarity select is set to non-inverting state.
NOTE
The analog comparator output is passed to COUTA only when
the WINDOW signal is high.
In actual operation, COUTA may lag the analog inputs by up to one bus clock cycle plus
the combinational path delay through the comparator and polarity select logic.

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Chapter 29 Comparator (CMP)

WI NDOW
Plus input
Minus input

CMPO

COUTA

Figure 29-20. Windowed mode operation
Internal bus

EN, PMODE,HYSCTR[1:0]

FILT_PER
INV
COS

OPE
WE

FILTER_CNT SE COUT

0x01

IER/F

CFR/F

0

INP

+

-

CMPO

Polarity
select

Window
control

Interrupt
control

Filter
block

INM

IRQ

COUT

To other SOC functions
WINDOW/SAMPLE

bus clock

Clock
prescaler

FILT_PER

1

0

0
divided
bus
clock

COUTA
CGMUX

SE=0

1

CMPO to
PAD

COS

Figure 29-21. Windowed mode

For control configurations which result in disabling the filter block, see Filter Block
Bypass Logic diagram.

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Functional description

When any windowed mode is active, COUTA is clocked by the bus clock whenever
WINDOW = 1. The last latched value is held when WINDOW = 0.

29.8.1.6 Windowed/Resampled mode (# 6)
The following figure uses the same input stimulus shown in Figure 29-20, and adds
resampling of COUTA to generate COUT. Samples are taken at the time points indicated
by the arrows in the figure. Again, prop delays and latency are ignored for the sake of
clarity.
This example was generated solely to demonstrate operation of the comparator in
windowed/resampled mode, and does not reflect any specific application. Depending
upon the sampling rate and window placement, COUT may not see zero-crossing events
detected by the analog comparator. Sampling period and/or window placement must be
carefully considered for a given application.
WI NDOW
Plus input
Minus input

CMPO

COUTA

COUT

Figure 29-22. Windowed/resampled mode operation

This mode of operation results in an unfiltered string of comparator samples where the
interval between the samples is determined by FPR[FILT_PER] and the bus clock rate.
Configuration for this mode is virtually identical to that for the Windowed/Filtered Mode
shown in the next section. The only difference is that the value of CR0[FILTER_CNT]
must be 1.

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Chapter 29 Comparator (CMP)

29.8.1.7 Windowed/Filtered mode (#7)
This is the most complex mode of operation for the comparator block, as it uses both
windowing and filtering features. It also has the highest latency of any of the modes. This
can be approximated: up to 1 bus clock synchronization in the window function +
((CR0[FILTER_CNT] * FPR[FILT_PER]) + 1) * bus clock for the filter function.
When any windowed mode is active, COUTA is clocked by the bus clock whenever
WINDOW = 1. The last latched value is held when WINDOW = 0.
Internal bus

EN, PMODE,HYSCTR[1:0]

FILT_PER
INV
COS

OPE
WE

FILTER_CNT SE COUT

> 0x01

1

INP

+

Polarity
CMPO select

-

Window
control

IER/F

CFR/F

0

Interrupt
control

Filter
block

INM

IRQ

COUT

To other SOC functions
WINDOW/SAMPLE

bus clock

Clock
prescaler

FILT_PER

1

0

0
divided
bus
clock

COUTA
CGMUX

SE=0

1

CMPO to
PAD

COS

Figure 29-23. Windowed/Filtered mode

29.8.2 Power modes
29.8.2.1 Wait mode operation
During Wait and VLPW modes, the CMP, if enabled, continues to operate normally and
a CMP interrupt can wake the MCU.
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Functional description

29.8.2.2 Stop mode operation
Depending on clock restrictions related to the MCU core or core peripherals, the MCU is
brought out of stop when a compare event occurs and the corresponding interrupt is
enabled. Similarly, if CR1[OPE] is enabled, the comparator output operates as in the
normal operating mode and comparator output is placed onto the external pin. In Stop
modes, the comparator can be operational in both:
• High-Speed (HS) Comparison mode when CR1[PMODE] = 1
• Low-Speed (LS) Comparison mode when CR1[PMODE] = 0
It is recommended to use the LS mode to minimize power consumption.
If stop is exited with a reset, all comparator registers are put into their reset state.

29.8.2.3 Low-Leakage mode operation
When the chip is in Low-Leakage modes:
• The CMP module is partially functional and is limited to Low-Speed mode,
regardless of CR1[PMODE] setting
• Windowed, Sampled, and Filtered modes are not supported
• The CMP output pin is latched and does not reflect the compare output state.
The positive- and negative-input voltage can be supplied from external pins or the DAC
output. The MCU can be brought out of the Low-Leakage mode if a compare event
occurs and the CMP interrupt is enabled. After wakeup from low-leakage modes, the
CMP module is in the reset state except for SCR[CFF] and SCR[CFR].

29.8.2.4 Background Debug Mode Operation
When the microcontroller is in active background debug mode, the CMP continues to
operate normally.

29.8.3 Startup and operation
A typical startup sequence is as follows.

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Chapter 29 Comparator (CMP)

The time required to stabilize COUT will be the power-on delay of the comparators plus
the largest propagation delay from a selected analog source through the analog
comparator, windowing function and filter. See the Data Sheets for power-on delays of
the comparators. The windowing function has a maximum of one bus clock period delay.
The filter delay is specified in the Low-pass filter.
During operation, the propagation delay of the selected data paths must always be
considered. It may take many bus clock cycles for COUT and SCR[CFR]/SCR[CFF] to
reflect an input change or a configuration change to one of the components involved in
the data path.
When programmed for filtering modes, COUT will initially be equal to 0, until sufficient
clock cycles have elapsed to fill all stages of the filter. This occurs even if COUTA is at a
logic 1.

29.8.4 Low-pass filter
The low-pass filter operates on the unfiltered and unsynchronized and optionally inverted
comparator output COUTA and generates the filtered and synchronized output COUT.
Both COUTA and COUT can be configured as module outputs and are used for different
purposes within the system.
Synchronization and edge detection are always used to determine status register bit
values. They also apply to COUT for all sampling and windowed modes. Filtering can be
performed using an internal timebase defined by FPR[FILT_PER], or using an external
SAMPLE input to determine sample time.
The need for digital filtering and the amount of filtering is dependent on user
requirements. Filtering can become more useful in the absence of an external hysteresis
circuit. Without external hysteresis, high-frequency oscillations can be generated at
COUTA when the selected INM and INP input voltages differ by less than the offset
voltage of the differential comparator.

29.8.4.1 Enabling filter modes
Filter modes can be enabled by:
• Setting CR0[FILTER_CNT] > 0x01 and
• Setting FPR[FILT_PER] to a nonzero value or setting CR1[SE]=1
If using the divided bus clock to drive the filter, it will take samples of COUTA every
FPR[FILT_PER] bus clock cycles.
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Functional description

The filter output will be at logic 0 when first initalized, and will subsequently change
when all the consecutive CR0[FILTER_CNT] samples agree that the output value has
changed. In other words, SCR[COUT] will be 0 for some initial period, even when
COUTA is at logic 1.
Setting both CR1[SE] and FPR[FILT_PER] to 0 disables the filter and eliminates
switching current associated with the filtering process.
Note
Always switch to this setting prior to making any changes in
filter parameters. This resets the filter to a known state.
Switching CR0[FILTER_CNT] on the fly without this
intermediate step can result in unexpected behavior.
If CR1[SE]=1, the filter takes samples of COUTA on each positive transition of the
sample input. The output state of the filter changes when all the consecutive
CR0[FILTER_CNT] samples agree that the output value has changed.

29.8.4.2 Latency issues
The value of FPR[FILT_PER] or SAMPLE period must be set such that the sampling
period is just longer than the period of the expected noise. This way a noise spike will
corrupt only one sample. The value of CR0[FILTER_CNT] must be chosen to reduce the
probability of noisy samples causing an incorrect transition to be recognized. The
probability of an incorrect transition is defined as the probability of an incorrect sample
raised to the power of CR0[FILTER_CNT].
The values of FPR[FILT_PER] or SAMPLE period and CR0[FILTER_CNT] must also
be traded off against the desire for minimal latency in recognizing actual comparator
output transitions. The probability of detecting an actual output change within the
nominal latency is the probability of a correct sample raised to the power of
CR0[FILTER_CNT].
The following table summarizes maximum latency values for the various modes of
operation in the absence of noise. Filtering latency is restarted each time an actual output
transition is masked by noise.
Table 29-16. Comparator sample/filter maximum latencies
Mode #

CR1[
EN]

CR1[
WE]

CR1[
SE]

CR0[FILTER
_CNT]

FPR[FILT_P
ER]

Operation

Maximum latency1

1

0

X

X

X

X

Disabled

N/A

Table continues on the next page...

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Chapter 29 Comparator (CMP)

Table 29-16. Comparator sample/filter maximum latencies (continued)
Mode #

CR1[
EN]

CR1[
WE]

CR1[
SE]

CR0[FILTER
_CNT]

FPR[FILT_P
ER]

Operation

Maximum latency1

2A

1

0

0

0x00

X

Continuous Mode

TPD

2B

1

0

0

X

0x00

3A

1

0

1

0x01

X

Sampled, Non-Filtered mode

TPD + TSAMPLE + Tper

3B

1

0

0

0x01

> 0x00

4A

1

0

1

> 0x01

X

4B

1

0

0

> 0x01

> 0x00

5A

1

1

0

0x00

X

5B

1

1

0

X

0x00

6

1

1

0

0x01

7

1

1

0

> 0x01

TPD + (FPR[FILT_PER] *
Tper) + Tper
Sampled, Filtered mode

TPD + (CR0[FILTER_CNT] *
TSAMPLE) + Tper
TPD + (CR0[FILTER_CNT] *
FPR[FILT_PER] x Tper) + Tper

Windowed mode

TPD + Tper

0x01 - 0xFF

Windowed / Resampled
mode

TPD + (FPR[FILT_PER] *
Tper) + 2Tper

0x01 - 0xFF

Windowed / Filtered mode

TPD + (CR0[FILTER_CNT] *
FPR[FILT_PER] x Tper) +
2Tper

TPD + Tper

1. TPD represents the intrinsic delay of the analog component plus the polarity select logic. TSAMPLE is the clock period of the
external sample clock. Tper is the period of the bus clock.

29.9 CMP interrupts
The CMP module is capable of generating an interrupt on either the rising- or fallingedge of the comparator output, or both. The following table gives the conditions in which
the interrupt request is asserted and deasserted.
When

Then

SCR[IER] and SCR[CFR] are set

The interrupt request is asserted

SCR[IEF] and SCR[CFF] are set

The interrupt request is asserted

SCR[IER] and SCR[CFR] are cleared for a rising-edge
interrupt

The interrupt request is deasserted

SCR[IEF] and SCR[CFF] are cleared for a falling-edge
interrupt

The interrupt request is deasserted

29.10 DMA support
Normally, the CMP generates a CPU interrupt if there is a change on the COUT. When
DMA support is enabled by setting SCR[DMAEN] and the interrupt is enabled by setting
SCR[IER], SCR[IEF], or both, the corresponding change on COUT forces a DMA
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CMP Asyncrhonous DMA support

transfer request rather than a CPU interrupt instead. When the DMA has completed the
transfer, it sends a transfer completing indicator that deasserts the DMA transfer request
and clears the flag to allow a subsequent change on comparator output to occur and force
another DMA request.
The comparator can remain functional in STOP modes. When DMA support is enabled
by setting SCR[DMAEN] and the interrupt is enabled by setting SCR[IER], SCR[IEF], or
both, the corresponding change on COUT forces a DMA transfer request to wake up the
system from STOP modes. After the data transfer has finished, system will go back to
STOP modes. Refer to DMA chapters in the device reference manual for the
asynchronous DMA function for details.

29.11 CMP Asyncrhonous DMA support
The comparator can remain functional in STOP modes. When DMA support is enabled
by setting SCR[DMAEN] and the interrupt is enabled by setting SCR[IER], SCR[IEF], or
both, the corresponding change on COUT forces a DMA transfer request to wake up the
system from STOP modes. After the data transfer has finished, system will go back to
STOP modes. Refer to DMA chapters in the device reference manual for the
asynchronous DMA function for details.

29.12 Digital-to-analog converter
The following figure shows the block diagram of the DAC module. It contains a 64-tap
resistor ladder network and a 64-to-1 multiplexer, which selects an output voltage from
one of 64 distinct levels that outputs from DACO. It is controlled through the DAC
Control Register (DACCR). Its supply reference source can be selected from two sources
Vin1 and Vin2. The module can be powered down or disabled when not in use. When in
Disabled mode, DACO is connected to the analog ground.

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Chapter 29 Comparator (CMP)

Vin1

Vin2

MUX

VRSEL

VOSEL[5:0]

DACEN

Vin

MUX

DACO

Figure 29-24. 6-bit DAC block diagram

29.13 DAC functional description
This section provides DAC functional description.

29.13.1 Voltage reference source select
• Vin1 connects to the primary voltage source as supply reference of 64 tap resistor
ladder
• Vin2 connects to an alternate voltage source

29.14 DAC resets
This module has a single reset input, corresponding to the chip-wide peripheral reset.

29.15 DAC clocks
This module has a single clock input, the bus clock.

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DAC interrupts

29.16 DAC interrupts
This module has no interrupts.

29.17 CMP Trigger Mode
CMP and DAC are configured to CMP Trigger mode when CMP_CR1[TRIGM] is set to
1. In addition, the CMP must be enabled. If the DAC is to be used as a reference to the
CMP, it must also be enabled.
CMP Trigger mode depends on an external timer resource to periodically enable the
CMP and 6-bit DAC in order to generate a triggered compare.
Upon setting TRIGM, the CMP and DAC are placed in a standby state until an external
timer resource trigger is received.
See the chip configuration chapter for details about the external timer resource.

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Chapter 30
12-bit Digital-to-Analog Converter (DAC)
30.1 Introduction
NOTE
For the chip-specific implementation details of this module's
instances see the chip configuration information.
The 12-bit digital-to-analog converter (DAC) is a low-power general-purpose DAC. The
output of this DAC can be placed on an external pin or set as one of the inputs to the
analog comparator, analog-to-digital converter (ADC), or other peripherals.

30.2 Features
The features of the DAC module include:
• On-chip programmable reference generator output. The voltage output range is from
1⁄4096 Vin to Vin, and the step is 1⁄4096 Vin, where Vin is the input voltage.
• Vin can be selected from two reference sources
• Static operation in Normal Stop mode
• 2-word data buffer supported with multiple operation modes
• DMA support

30.3 Block diagram
The block diagram of the DAC module is as follows:

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Block diagram
DACREF_1

DACREF_2

DACRFS

MUX

AMP buffer

Vin
DACEN

MUX

4096-level

VDD

-

LPEN
Vo

Vout

+

DACDAT[11:0]

12

Hardware trigger

DACBFWMF

DACSWTRG
DACBFWM
DACBFEN
DACBFUP
DACBFRP

Data
Buffer

DACBWIEN

&

DACBFRPTF
DACBTIEN

&

dac_interrupt

OR

DACBFRPBF
DACBBIEN

&

DACBFMD
DACTRGSE

Figure 30-1. DAC block diagram

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Chapter 30 12-bit Digital-to-Analog Converter (DAC)

30.4 Memory map/register definition
The DAC has registers to control analog comparator and programmable voltage divider
to perform the digital-to-analog functions.
The address of a register is the sum of a base address and an address offset. The base
address is defined at the chip level. The address offset is defined at the module level.
DAC memory map
Absolute
address
(hex)

Width
Access
(in bits)

Register name

Reset value

Section/
page

4003_F000

DAC Data Low Register (DAC0_DAT0L)

8

R/W

00h

30.4.1/539

4003_F001

DAC Data High Register (DAC0_DAT0H)

8

R/W

00h

30.4.2/540

4003_F002

DAC Data Low Register (DAC0_DAT1L)

8

R/W

00h

30.4.1/539

4003_F003

DAC Data High Register (DAC0_DAT1H)

8

R/W

00h

30.4.2/540

4003_F020

DAC Status Register (DAC0_SR)

8

R/W

02h

30.4.3/540

4003_F021

DAC Control Register (DAC0_C0)

8

R/W

00h

30.4.4/541

4003_F022

DAC Control Register 1 (DAC0_C1)

8

R/W

00h

30.4.5/542

4003_F023

DAC Control Register 2 (DAC0_C2)

8

R/W

01h

30.4.6/542

30.4.1 DAC Data Low Register (DACx_DATnL)
Address: 4003_F000h base + 0h offset + (2d × i), where i=0d to 1d
Bit

Read
Write
Reset

7

6

5

4

3

2

1

0

0

0

0

0

DATA0
0

0

0

0

DACx_DATnL field descriptions
Field
7–0
DATA0

Description
When the DAC buffer is not enabled, DATA[11:0] controls the output voltage based on the following
formula: V out = V in * (1 + DACDAT0[11:0])/4096
When the DAC buffer is enabled, DATA is mapped to the 16-word buffer.

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30.4.2 DAC Data High Register (DACx_DATnH)
Address: 4003_F000h base + 1h offset + (2d × i), where i=0d to 1d
Bit

Read
Write
Reset

7

6

5

4

3

2

0
0

0

1

0

0

0

DATA1
0

0

0

0

DACx_DATnH field descriptions
Field
7–4
Reserved
3–0
DATA1

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
When the DAC Buffer is not enabled, DATA[11:0] controls the output voltage based on the following
formula. V out = V in * (1 + DACDAT0[11:0])/4096
When the DAC buffer is enabled, DATA[11:0] is mapped to the 16-word buffer.

30.4.3 DAC Status Register (DACx_SR)
If DMA is enabled, the flags can be cleared automatically by DMA when the DMA
request is done. Writing 0 to a field clears it whereas writing 1 has no effect. After reset,
DACBFRPTF is set and can be cleared by software, if needed. The flags are set only
when the data buffer status is changed.
Address: 4003_F000h base + 20h offset = 4003_F020h
Bit

Read
Write
Reset

7

6

5

4

3

2

1

0
0

0

0

0

DACBFRPT DACBFRPB
F
F
0

0

0

1

0

DACx_SR field descriptions
Field
7–2
Reserved

Description
This field is reserved.
This read-only field is reserved and always has the value 0.

1
DACBFRPTF

DAC Buffer Read Pointer Top Position Flag

0
DACBFRPBF

DAC Buffer Read Pointer Bottom Position Flag

0
1

0
1

The DAC buffer read pointer is not zero.
The DAC buffer read pointer is zero.

The DAC buffer read pointer is not equal to C2[DACBFUP].
The DAC buffer read pointer is equal to C2[DACBFUP].

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Chapter 30 12-bit Digital-to-Analog Converter (DAC)

30.4.4 DAC Control Register (DACx_C0)
Address: 4003_F000h base + 21h offset = 4003_F021h
Bit

Read
Write
Reset

7

6

DACEN

DACRFS

0

0

5

4

3

0

DACTRGSE
L
DACSWTRG
0

0

LPEN
0

2

0

0

1

0

DACBTIEN

DACBBIEN

0

0

DACx_C0 field descriptions
Field
7
DACEN

Description
DAC Enable
Starts the Programmable Reference Generator operation.
0
1

6
DACRFS

The DAC system is disabled.
The DAC system is enabled.

DAC Reference Select
0
1

The DAC selects DACREF_1 as the reference voltage.
The DAC selects DACREF_2 as the reference voltage.

5
DACTRGSEL

DAC Trigger Select

4
DACSWTRG

DAC Software Trigger

0
1

Active high. This is a write-only field, which always reads 0. If DAC software trigger is selected and buffer
is enabled, writing 1 to this field will advance the buffer read pointer once.
0
1

3
LPEN

The DAC hardware trigger is selected.
The DAC software trigger is selected.

The DAC soft trigger is not valid.
The DAC soft trigger is valid.

DAC Low Power Control
NOTE: See the 12-bit DAC electrical characteristics of the device data sheet for details on the impact of
the modes below.
0
1

2
Reserved

High-Power mode
Low-Power mode

This field is reserved.
This read-only field is reserved and always has the value 0.

1
DACBTIEN

DAC Buffer Read Pointer Top Flag Interrupt Enable

0
DACBBIEN

DAC Buffer Read Pointer Bottom Flag Interrupt Enable

0
1

0
1

The DAC buffer read pointer top flag interrupt is disabled.
The DAC buffer read pointer top flag interrupt is enabled.

The DAC buffer read pointer bottom flag interrupt is disabled.
The DAC buffer read pointer bottom flag interrupt is enabled.

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30.4.5 DAC Control Register 1 (DACx_C1)
Address: 4003_F000h base + 22h offset = 4003_F022h
Bit

Read
Write
Reset

7

6

5

DMAEN
0

4

3

0
0

0

0

0

2

1

0

DACBFMD

0

DACBFEN

0

0

0

DACx_C1 field descriptions
Field
7
DMAEN

6–3
Reserved
2
DACBFMD

Description
DMA Enable Select
0
1

DMA is disabled.
DMA is enabled. When DMA is enabled, the DMA request will be generated by original interrupts. The
interrupts will not be presented on this module at the same time.

This field is reserved.
This read-only field is reserved and always has the value 0.
DAC Buffer Work Mode Select
0
1

Normal mode
One-Time Scan mode

1
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

0
DACBFEN

DAC Buffer Enable
0
1

Buffer read pointer is disabled. The converted data is always the first word of the buffer.
Buffer read pointer is enabled. The converted data is the word that the read pointer points to. It means
converted data can be from any word of the buffer.

30.4.6 DAC Control Register 2 (DACx_C2)
Address: 4003_F000h base + 23h offset = 4003_F023h
Bit

Read
Write
Reset

7

6

5

0
0

4

3

0

0

1

0

DACBFRP

0

2

0

0

DACBFUP

0

0

1

DACx_C2 field descriptions
Field

Description

7–5
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

4
DACBFRP

DAC Buffer Read Pointer
Keeps the current value of the buffer read pointer.
Table continues on the next page...

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Chapter 30 12-bit Digital-to-Analog Converter (DAC)

DACx_C2 field descriptions (continued)
Field

Description

3–1
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

0
DACBFUP

DAC Buffer Upper Limit
Selects the upper limit of the DAC buffer. The buffer read pointer cannot exceed it.

30.5 Functional description
The 12-bit DAC module can select one of the two reference inputs—DACREF_1 and
DACREF_2 as the DAC reference voltage, Vin by C0[DACRFS]. See the module
introduction for information on the source for DACREF_1 and DACREF_2.
When the DAC is enabled, it converts the data in DACDAT0[11:0] or the data from the
DAC data buffer to a stepped analog output voltage. The output voltage range is from Vin
to Vin∕4096, and the step is Vin∕4096.

30.5.1 DAC data buffer operation
When the DAC is enabled and the buffer is not enabled, the DAC module always
converts the data in DAT0 to analog output voltage.
When both the DAC and the buffer are enabled, the DAC converts the data in the data
buffer to analog output voltage. The data buffer read pointer advances to the next word
whenever any hardware or software trigger event occurs. Refer to Introduction for the
hardware trigger connection.
The data buffer can be configured to operate in Normal mode, Swing mode, or One-Time
Scan mode. When the buffer operation is switched from one mode to another, the read
pointer does not change. The read pointer can be set to any value between 0 and
C2[DACBFUP] by writing C2[DACBFRP].

30.5.1.1 DAC data buffer interrupts
There are several interrupts and associated flags that can be configured for the DAC
buffer. SR[DACBFRPBF] is set when the DAC buffer read pointer reaches the DAC
buffer upper limit, that is, C2[DACBFRP] = C2[DACBFUP]. SR[DACBFRPTF] is set
when the DAC read pointer is equal to the start position, 0.

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Functional description

30.5.1.2 Modes of DAC data buffer operation
The following table describes the different modes of data buffer operation for the DAC
module.
Table 30-23. Modes of DAC data buffer operation
Modes

Description

Buffer Normal mode

This is the default mode. The buffer works as a circular buffer.
The read pointer increases by one, every time the trigger
occurs. When the read pointer reaches the upper limit, it goes
to 0 directly in the next trigger event.

Buffer One-time Scan mode

The read pointer increases by 1 every time the trigger occurs.
When it reaches the upper limit, it stops there. If read pointer
is reset to the address other than the upper limit, it will
increase to the upper address and stop there again.
NOTE: If the software set the read pointer to the upper limit,
the read pointer will not advance in this mode.

30.5.2 DMA operation
When DMA is enabled, DMA requests are generated instead of interrupt requests. The
DMA Done signal clears the DMA request.
The status register flags are still set and are cleared automatically when the DMA
completes.

30.5.3 Resets
During reset, the DAC is configured in the default mode and is disabled.

30.5.4 Low-Power mode operation
The following table shows the wait mode and the stop mode operation of the DAC
module.
Table 30-24. Modes of operation
Modes of operation
Wait mode

Description
The DAC will operate normally, if enabled.

Table continues on the next page...

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Chapter 30 12-bit Digital-to-Analog Converter (DAC)

Table 30-24. Modes of operation (continued)
Modes of operation

Description

Stop mode

If enabled, the DAC module continues to operate
in Normal Stop mode and the output voltage will
hold the value before stop.

In low-power stop modes, the DAC is fully
shut down.

NOTE
The assignment of module modes to core modes is chipspecific. For module-to-core mode assignments, see the chapter
that describes how modules are configured.

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Chapter 31
Timer/PWM Module (TPM)
31.1 Introduction
The TPM (Timer/PWM Module) is a two to eight channel timer which supports input
capture, output compare, and the generation of PWM signals to control electric motor and
power management applications. The counter, compare and capture registers are clocked
by an asynchronous clock that can remain enabled in low power modes.

31.1.1 TPM Philosophy
The TPM is built upon a very simple timer (HCS08 Timer PWM Module – TPM) used
for many years on Freescale's 8-bit microcontrollers. The TPM extends the functionality
to support operation in low power modes by clocking the counter, compare and capture
registers from an asynchronous clock that can remain functional in low power modes.

31.1.2 Features
The TPM features include:
• TPM clock mode is selectable
• Can increment on every edge of the asynchronous counter clock
• Can increment on rising edge of an external clock input synchronized to the
asynchronous counter clock
• Prescaler divide-by 1, 2, 4, 8, 16, 32, 64, or 128
• TPM includes a 16-bit counter

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Introduction

• It can be a free-running counter or modulo counter
• The counting can be up or up-down
• Includes 6 channels that can be configured for input capture, output compare, or
edge-aligned PWM mode
• In input capture mode the capture can occur on rising edges, falling edges or
both edges
• In output compare mode the output signal can be set, cleared, pulsed, or toggled
on match
• All channels can be configured for center-aligned PWM mode
• Support the generation of an interrupt and/or DMA request per channel
• Support the generation of an interrupt and/or DMA request when the counter
overflows
• Support selectable trigger input to optionally reset or cause the counter to start
incrementing.
• The counter can also optionally stop incrementing on counter overflow
• Support the generation of hardware triggers when the counter overflows and per
channel

31.1.3 Modes of Operation
During debug mode, the TPM can can be configured to temporarily pause all counting
until the core returns to normal user operating mode or to operate normally. When the
counter is paused, trigger inputs and input capture events are ignored.
During doze mode, the TPM can be configured to operate normally or to pause all
counting for the duration of doze mode. When the counter is paused, trigger inputs and
input capture events are ignored.
During stop mode, the TPM counter clock can remain functional and the TPM can
generate an asynchronous interrupt to exit the MCU from stop mode.

31.1.4 Block Diagram
The TPM uses one input/output (I/O) pin per channel, CHn (TPM channel (n)) where n is
the channel number.
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Chapter 31 Timer/PWM Module (TPM)

The following figure shows the TPM structure. The central component of the TPM is the
16-bit counter with programmable final value and its counting can be up or up-down.
CMOD
no clock selected
(counter disable)
module clock

PS

external clock

prescaler

synchronizer

3

(1, 2, 4, 8, 16, 32, 64 or 128)

CPWMS

Module counter

TOIE
MOD

CH0IE
CH0F

input capture
mode logic

channel 0
interrupt

output modes logic
(generation of channel 0 outputs signals in
output compare, EPWM and CPWM modes)

C0V

channel 0
output signal

Channel N

MSNB:MSNA
ELSNB:ELSNA

CHNIE
CHNF

channel N
input

timer overflow
interrupt

Channel 0

MS0B:MS0A
ELS0B:ELS0A

channel 0
input

TOF

input capture
mode logic

CNV

channel N
interrupt

output modes logic
(generation of channel N outputs signals in
output compare, EPWM and CPWM modes)

channel N
output signal

Figure 31-1. TPM block diagram

31.2 TPM Signal Descriptions
Table 31-1 shows the user-accessible signals for the TPM.
Table 31-1. TPM signal descriptions
Signal
TPM_EXTCLK
TPM_CHn

Description
External clock. TPM external clock can be selected to increment the TPM
counter on every rising edge synchronized to the counter clock.
TPM channel (n = 5 to 0)

I/O
I
I/O

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31.2.1 TPM_EXTCLK — TPM External Clock
The rising edge of the external input signal is used to increment the TPM counter if
selected by CMOD[1:0] bits in the SC register. This input signal must be less than half of
the TPM counter clock frequency. The TPM counter prescaler selection and settings are
also used when an external input is selected.

31.2.2 TPM_CHn — TPM Channel (n) I/O Pin
Each TPM channel can be configured to operate either as input or output. The direction
associated with each channel, input or output, is selected according to the mode assigned
for that channel.

31.3 Memory Map and Register Definition
This section provides a detailed description of all TPM registers.
Attempting to access a reserved register location in the TPM memory map will generate a
bus error.
TPM memory map
Absolute
address
(hex)

Register name

Width
Access
(in bits)

Reset value

Section/
page

4003_8000

Status and Control (TPM0_SC)

32

R/W

0000_0000h

31.3.1/552

4003_8004

Counter (TPM0_CNT)

32

R/W

0000_0000h

31.3.2/553

4003_8008

Modulo (TPM0_MOD)

32

R/W

0000_FFFFh

31.3.3/554

4003_800C

Channel (n) Status and Control (TPM0_C0SC)

32

R/W

0000_0000h

31.3.4/555

4003_8010

Channel (n) Value (TPM0_C0V)

32

R/W

0000_0000h

31.3.5/557

4003_8014

Channel (n) Status and Control (TPM0_C1SC)

32

R/W

0000_0000h

31.3.4/555

4003_8018

Channel (n) Value (TPM0_C1V)

32

R/W

0000_0000h

31.3.5/557

4003_801C

Channel (n) Status and Control (TPM0_C2SC)

32

R/W

0000_0000h

31.3.4/555

4003_8020

Channel (n) Value (TPM0_C2V)

32

R/W

0000_0000h

31.3.5/557

4003_8024

Channel (n) Status and Control (TPM0_C3SC)

32

R/W

0000_0000h

31.3.4/555

4003_8028

Channel (n) Value (TPM0_C3V)

32

R/W

0000_0000h

31.3.5/557

4003_802C

Channel (n) Status and Control (TPM0_C4SC)

32

R/W

0000_0000h

31.3.4/555

4003_8030

Channel (n) Value (TPM0_C4V)

32

R/W

0000_0000h

31.3.5/557

4003_8034

Channel (n) Status and Control (TPM0_C5SC)

32

R/W

0000_0000h

31.3.4/555

4003_8038

Channel (n) Value (TPM0_C5V)

32

R/W

0000_0000h

31.3.5/557

4003_8050

Capture and Compare Status (TPM0_STATUS)

32

R/W

0000_0000h

31.3.6/557

4003_8084

Configuration (TPM0_CONF)

32

R/W

0000_0000h

31.3.7/559

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TPM memory map (continued)
Absolute
address
(hex)

Register name

Width
Access
(in bits)

Reset value

Section/
page

4003_9000

Status and Control (TPM1_SC)

32

R/W

0000_0000h

31.3.1/552

4003_9004

Counter (TPM1_CNT)

32

R/W

0000_0000h

31.3.2/553

4003_9008

Modulo (TPM1_MOD)

32

R/W

0000_FFFFh

31.3.3/554

4003_900C

Channel (n) Status and Control (TPM1_C0SC)

32

R/W

0000_0000h

31.3.4/555

4003_9010

Channel (n) Value (TPM1_C0V)

32

R/W

0000_0000h

31.3.5/557

4003_9014

Channel (n) Status and Control (TPM1_C1SC)

32

R/W

0000_0000h

31.3.4/555

4003_9018

Channel (n) Value (TPM1_C1V)

32

R/W

0000_0000h

31.3.5/557

4003_901C

Channel (n) Status and Control (TPM1_C2SC)

32

R/W

0000_0000h

31.3.4/555

4003_9020

Channel (n) Value (TPM1_C2V)

32

R/W

0000_0000h

31.3.5/557

4003_9024

Channel (n) Status and Control (TPM1_C3SC)

32

R/W

0000_0000h

31.3.4/555

4003_9028

Channel (n) Value (TPM1_C3V)

32

R/W

0000_0000h

31.3.5/557

4003_902C

Channel (n) Status and Control (TPM1_C4SC)

32

R/W

0000_0000h

31.3.4/555

4003_9030

Channel (n) Value (TPM1_C4V)

32

R/W

0000_0000h

31.3.5/557

4003_9034

Channel (n) Status and Control (TPM1_C5SC)

32

R/W

0000_0000h

31.3.4/555

4003_9038

Channel (n) Value (TPM1_C5V)

32

R/W

0000_0000h

31.3.5/557

4003_9050

Capture and Compare Status (TPM1_STATUS)

32

R/W

0000_0000h

31.3.6/557

4003_9084

Configuration (TPM1_CONF)

32

R/W

0000_0000h

31.3.7/559

4003_A000

Status and Control (TPM2_SC)

32

R/W

0000_0000h

31.3.1/552

4003_A004

Counter (TPM2_CNT)

32

R/W

0000_0000h

31.3.2/553

4003_A008

Modulo (TPM2_MOD)

32

R/W

0000_FFFFh

31.3.3/554

4003_A00C Channel (n) Status and Control (TPM2_C0SC)

32

R/W

0000_0000h

31.3.4/555

4003_A010

Channel (n) Value (TPM2_C0V)

32

R/W

0000_0000h

31.3.5/557

4003_A014

Channel (n) Status and Control (TPM2_C1SC)

32

R/W

0000_0000h

31.3.4/555

4003_A018

Channel (n) Value (TPM2_C1V)

32

R/W

0000_0000h

31.3.5/557

4003_A01C Channel (n) Status and Control (TPM2_C2SC)

32

R/W

0000_0000h

31.3.4/555

4003_A020

Channel (n) Value (TPM2_C2V)

32

R/W

0000_0000h

31.3.5/557

4003_A024

Channel (n) Status and Control (TPM2_C3SC)

32

R/W

0000_0000h

31.3.4/555

4003_A028

Channel (n) Value (TPM2_C3V)

32

R/W

0000_0000h

31.3.5/557

4003_A02C Channel (n) Status and Control (TPM2_C4SC)

32

R/W

0000_0000h

31.3.4/555

4003_A030

Channel (n) Value (TPM2_C4V)

32

R/W

0000_0000h

31.3.5/557

4003_A034

Channel (n) Status and Control (TPM2_C5SC)

32

R/W

0000_0000h

31.3.4/555

4003_A038

Channel (n) Value (TPM2_C5V)

32

R/W

0000_0000h

31.3.5/557

4003_A050

Capture and Compare Status (TPM2_STATUS)

32

R/W

0000_0000h

31.3.6/557

4003_A084

Configuration (TPM2_CONF)

32

R/W

0000_0000h

31.3.7/559

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31.3.1 Status and Control (TPMx_SC)
SC contains the overflow status flag and control bits used to configure the interrupt
enable, module configuration and prescaler factor. These controls relate to all channels
within this module.
Address: Base address + 0h offset
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

0

R

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Bit

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

TOIE

0

0

TOF

Reset

CPWMS

W

0

R

DMA

PS

w1c

W

Reset

CMOD

0

0

0

0

0

0

0

0

0

0

0

0

0

0

TPMx_SC field descriptions
Field
31–9
Reserved
8
DMA

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
DMA Enable
Enables DMA transfers for the overflow flag.
0
1

7
TOF

Disables DMA transfers.
Enables DMA transfers.

Timer Overflow Flag
Set by hardware when the LPTPM counter equals the value in the MOD register and increments. The TOF
bit is cleared by writing a 1 to TOF bit. Writing a 0 to TOF has no effect.
If another LPTPM overflow occurs between the flag setting and the flag clearing, the write operation has
no effect; therefore, TOF remains set indicating another overflow has occurred. In this case a TOF
interrupt request is not lost due to a delay in clearing the previous TOF.
Table continues on the next page...

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Chapter 31 Timer/PWM Module (TPM)

TPMx_SC field descriptions (continued)
Field

Description
0
1

6
TOIE

Timer Overflow Interrupt Enable
Enables LPTPM overflow interrupts.
0
1

5
CPWMS

LPTPM counter has not overflowed.
LPTPM counter has overflowed.

Disable TOF interrupts. Use software polling or DMA request.
Enable TOF interrupts. An interrupt is generated when TOF equals one.

Center-aligned PWM Select
Selects CPWM mode. This mode configures the LPTPM to operate in up-down counting mode.
This field is write protected. It can be written only when the counter is disabled.
0
1

4–3
CMOD

Clock Mode Selection
Selects the LPTPM counter clock modes. When disabling the counter, this field remain set until
acknolwedged in the LPTPM clock domain.
00
01
10
11

2–0
PS

LPTPM counter operates in up counting mode.
LPTPM counter operates in up-down counting mode.

LPTPM counter is disabled
LPTPM counter increments on every LPTPM counter clock
LPTPM counter increments on rising edge of LPTPM_EXTCLK synchronized to the LPTPM counter
clock
Reserved

Prescale Factor Selection
Selects one of 8 division factors for the clock mode selected by CMOD.
This field is write protected. It can be written only when the counter is disabled.
000
001
010
011
100
101
110
111

Divide by 1
Divide by 2
Divide by 4
Divide by 8
Divide by 16
Divide by 32
Divide by 64
Divide by 128

31.3.2 Counter (TPMx_CNT)
The CNT register contains the LPTPM counter value.
Reset clears the CNT register. Writing any value to COUNT also clears the counter.
When debug is active, the LPTPM counter does not increment unless configured
otherwise.
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Reading the CNT register adds two wait states to the register access due to
synchronization delays.
Address: Base address + 4h offset
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

0

R

0

0

0

0

0

0

0

0

7

6

5

4

3

2

1

0

0

0

0

0

0

0

0

COUNT

W
Reset

8

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

TPMx_CNT field descriptions
Field

Description

31–16
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

15–0
COUNT

Counter value

31.3.3 Modulo (TPMx_MOD)
The Modulo register contains the modulo value for the LPTPM counter. When the
LPTPM counter reaches the modulo value and increments, the overflow flag (TOF) is set
and the next value of LPTPM counter depends on the selected counting method (see
Counter ).
Writing to the MOD register latches the value into a buffer. The MOD register is updated
with the value of its write buffer according to MOD Register Update .
It is recommended to initialize the LPTPM counter (write to CNT) before writing to the
MOD register to avoid confusion about when the first counter overflow will occur.
Address: Base address + 8h offset
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

0

R

0

0

0

0

0

0

0

0

7

6

5

4

3

2

1

0

1

1

1

1

1

1

1

MOD

W
Reset

8

0

0

0

0

0

0

0

0

1

1

1

1

1

1

1

1

1

TPMx_MOD field descriptions
Field
31–16
Reserved
15–0
MOD

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
Modulo value
When writing this field, all bytes must be written at the same time.

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Chapter 31 Timer/PWM Module (TPM)

31.3.4 Channel (n) Status and Control (TPMx_CnSC)
CnSC contains the channel-interrupt-status flag and control bits used to configure the
interrupt enable, channel configuration, and pin function. When switching from one
channel mode to a different channel mode, the channel must first be disabled and this
must be acknowledged in the LPTPM counter clock domain.
Table 31-34. Mode, Edge, and Level Selection
CPWMS

MSnB:MSnA

ELSnB:ELSnA

Mode

Configuration

X

00

00

None

Channel disabled

X

01/10/11

00

Software compare

Pin not used for LPTPM

0

00

01

Input capture

Capture on Rising Edge
Only

01

10

Capture on Falling
Edge Only

11

Capture on Rising or
Falling Edge

01

10

Output compare

Toggle Output on
match

10

Clear Output on match

11

Set Output on match

10

Edge-aligned PWM

High-true pulses (clear
Output on match, set
Output on reload)

X1

11

Low-true pulses (set
Output on match, clear
Output on reload)

10

Output compare

Pulse Output low on
match

X1
1

10

Pulse Output high on
match

10

Center-aligned PWM

High-true pulses (clear
Output on match-up,
set Output on matchdown)

X1

Low-true pulses (set
Output on match-up,
clear Output on matchdown)

Address: Base address + Ch offset + (8d × i), where i=0d to 5d
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

0

0

0

0

0

0

0

0

0

R
W

Reset

0

0

0

0

0

0

0

0

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Bit

15

14

13

12

11

10

9

8

0

R

CHF
w1c

W

Reset

7

0

0

0

0

0

0

0

0

0

6

5

CHIE

MSB

0

0

4

3

2

MSA ELSB ELSA
0

0

0

1

0

0

0

DMA
0

TPMx_CnSC field descriptions
Field
31–8
Reserved
7
CHF

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
Channel Flag
Set by hardware when an event occurs on the channel. CHF is cleared by writing a 1 to the CHF bit.
Writing a 0 to CHF has no effect.
If another event occurs between the CHF sets and the write operation, the write operation has no effect;
therefore, CHF remains set indicating another event has occurred. In this case a CHF interrupt request is
not lost due to the delay in clearing the previous CHF.
0
1

6
CHIE

No channel event has occurred.
A channel event has occurred.

Channel Interrupt Enable
Enables channel interrupts.
0
1

Disable channel interrupts.
Enable channel interrupts.

5
MSB

Channel Mode Select

4
MSA

Channel Mode Select

3
ELSB

Edge or Level Select

2
ELSA

Edge or Level Select

1
Reserved
0
DMA

Used for further selections in the channel logic. Its functionality is dependent on the channel mode. When
a channel is disabled, this bit will not change state until acknowledged in the LPTPM counter clock
domain.

Used for further selections in the channel logic. Its functionality is dependent on the channel mode. When
a channel is disabled, this bit will not change state until acknowledged in the LPTPM counter clock
domain.

The functionality of ELSB and ELSA depends on the channel mode. When a channel is disabled, this bit
will not change state until acknowledged in the LPTPM counter clock domain.

The functionality of ELSB and ELSA depends on the channel mode. When a channel is disabled, this bit
will not change state until acknowledged in the LPTPM counter clock domain.
This field is reserved.
This read-only field is reserved and always has the value 0.
DMA Enable
Enables DMA transfers for the channel.
0
1

Disable DMA transfers.
Enable DMA transfers.

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Chapter 31 Timer/PWM Module (TPM)

31.3.5 Channel (n) Value (TPMx_CnV)
These registers contain the captured LPTPM counter value for the input modes or the
match value for the output modes.
In input capture mode, any write to a CnV register is ignored.
In compare modes, writing to a CnV register latches the value into a buffer. A CnV
register is updated with the value of its write buffer according to CnV Register Update .
Address: Base address + 10h offset + (8d × i), where i=0d to 5d
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

0

R

0

0

0

0

0

0

0

0

7

6

5

4

3

2

1

0

0

0

0

0

0

0

0

VAL

W
Reset

8

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

TPMx_CnV field descriptions
Field
31–16
Reserved
15–0
VAL

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
Channel Value
Captured LPTPM counter value of the input modes or the match value for the output modes. When writing
this field, all bytes must be written at the same time.

31.3.6 Capture and Compare Status (TPMx_STATUS)
The STATUS register contains a copy of the status flag CHnF bit (in CnSC) for each
LPTPM channel, as well as the TOF bit (in SC), for software convenience.
Each CHnF bit in STATUS is a mirror of CHnF bit in CnSC. All CHnF bits can be
checked using only one read of STATUS. All CHnF bits can be cleared by writing all
ones to STATUS.
Hardware sets the individual channel flags when an event occurs on the channel. CHF is
cleared by writing a 1 to the CHF bit. Writing a 0 to CHF has no effect.
If another event occurs between the flag setting and the write operation, the write
operation has no effect; therefore, CHF remains set indicating another event has occurred.
In this case a CHF interrupt request is not lost due to the clearing sequence for a previous
CHF.

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Address: Base address + 50h offset
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

0

R

W

0

0

0

0

0

0

0

0

0

0

Bit

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

R

w1c

W

Reset

0

0

0

0

0

0

0

0

0

0

0

CH0F

0

CH1F

0

CH2F

0

CH3F

0

CH4F

0

CH5F

0

TOF

Reset

w1c

w1c

w1c

w1c

w1c

w1c

0

0

0

0

0

0

TPMx_STATUS field descriptions
Field
31–9
Reserved
8
TOF

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
Timer Overflow Flag
See register description
0
1

7–6
Reserved
5
CH5F

This field is reserved.
This read-only field is reserved and always has the value 0.
Channel 5 Flag
See the register description.
0
1

4
CH4F

No channel event has occurred.
A channel event has occurred.

Channel 4 Flag
See the register description.
0
1

3
CH3F

LPTPM counter has not overflowed.
LPTPM counter has overflowed.

No channel event has occurred.
A channel event has occurred.

Channel 3 Flag
See the register description.
0
1

No channel event has occurred.
A channel event has occurred.
Table continues on the next page...

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Chapter 31 Timer/PWM Module (TPM)

TPMx_STATUS field descriptions (continued)
Field

Description

2
CH2F

Channel 2 Flag
See the register description.
0
1

1
CH1F

No channel event has occurred.
A channel event has occurred.

Channel 1 Flag
See the register description.
0
1

0
CH0F

No channel event has occurred.
A channel event has occurred.

Channel 0 Flag
See the register description.
0
1

No channel event has occurred.
A channel event has occurred.

31.3.7 Configuration (TPMx_CONF)
This register selects the behavior in debug and wait modes and the use of an external
global time base.
Address: Base address + 84h offset
Bit

31

30

29

28

27

26

25

24

23

22

0

20

19

CSOT

16

CSOO

17

CROT

0

18

Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Bit

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

GTBEEN

R

21

0

0

0

0

0

TRGSEL
W

W

Reset

0

0

0

0

0

0

DBGMODE

0

0

0

DOZEEN

0

R

0

0

0

0

TPMx_CONF field descriptions
Field
31–28
Reserved

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
Table continues on the next page...

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TPMx_CONF field descriptions (continued)
Field

Description

27–24
TRGSEL

Trigger Select

23–19
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

18
CROT

Selects the input trigger to use for starting the counter and/or reloading the counter. This field should only
be changed when the LPTPM counter is disabled. See Chip configuration section for available options.

Counter Reload On Trigger
When set, the LPTPM counter will reload with zero (and initialize PWM outputs to their default value) when
a rising edge is detected on the selected trigger input.
The trigger input is ignored if the LPTPM counter is paused during debug mode or doze mode. This field
should only be changed when the LPTPM counter is disabled.
0
1

17
CSOO

Counter is not reloaded due to a rising edge on the selected input trigger
Counter is reloaded when a rising edge is detected on the selected input trigger

Counter Stop On Overflow
When set, the LPTPM counter will stop incrementing once the counter equals the MOD value and
incremented (this also sets the TOF). Reloading the counter with zero due to writing to the counter register
or due to a trigger input does not cause the counter to stop incrementing. Once the counter has stopped
incrementing, the counter will not start incrementing unless it is disabled and then enabled again, or a
rising edge on the selected trigger input is detected when CSOT set.
This field should only be changed when the LPTPM counter is disabled.
0
1

16
CSOT

LPTPM counter continues incrementing or decrementing after overflow
LPTPM counter stops incrementing or decrementing after overflow.

Counter Start on Trigger
When set, the LPTPM counter will not start incrementing after it is enabled until a rising edge on the
selected trigger input is detected. If the LPTPM counter is stopped due to an overflow, a rising edge on the
selected trigger input will also cause the LPTPM counter to start incrementing again.
The trigger input is ignored if the LPTPM counter is paused during debug mode or doze mode. This field
should only be changed when the LPTPM counter is disabled.
0
1

LPTPM counter starts to increment immediately, once it is enabled.
LPTPM counter only starts to increment when it a rising edge on the selected input trigger is detected,
after it has been enabled or after it has stopped due to overflow.

15–10
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

9
GTBEEN

Global time base enable
Configures the LPTPM to use an externally generated global time base counter. When an externally
generated timebase is used, the internal LPTPM counter is not used by the channels but can be used to
generate a periodic interrupt or DMA request using the Modulo register and timer overflow flag.
0
1

8
Reserved
7–6
DBGMODE

All channels use the internally generated LPTPM counter as their timebase
All channels use an externally generated global timebase as their timebase

This field is reserved.
This read-only field is reserved and always has the value 0.
Debug Mode
Table continues on the next page...

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Chapter 31 Timer/PWM Module (TPM)

TPMx_CONF field descriptions (continued)
Field

Description
Configures the LPTPM behavior in debug mode. All other configurations are reserved.
00
11

5
DOZEEN

Doze Enable
Configures the LPTPM behavior in wait mode.
0
1

4–0
Reserved

LPTPM counter is paused and does not increment during debug mode. Trigger inputs and input
capture events are also ignored.
LPTPM counter continues in debug mode.

Internal LPTPM counter continues in Doze mode.
Internal LPTPM counter is paused and does not increment during Doze mode. Trigger inputs and
input capture events are also ignored.

This field is reserved.
This read-only field is reserved and always has the value 0.

31.4 Functional Description
The following sections describe the TPM features.

31.4.1 Clock Domains
The TPM module supports two clock domains.
The bus clock domain is used by the register interface and for synchronizing interrupts
and DMA requests.
The TPM counter clock domain is used to clock the counter and prescaler along with the
output compare and input capture logic. The TPM counter clock is considered
asynchronous to the bus clock, can be a higher or lower frequency than the bus clock and
can remain operational in Stop mode. Multiple TPM instances are all clocked by the
same TPM counter clock in support of the external timebase feature.

31.4.1.1 Counter Clock Mode
The CMOD[1:0] bits in the SC register either disable the TPM counter or select one of
two possible clock modes for the TPM counter. After any reset, CMOD[1:0] = 0:0 so the
TPM counter is disabled.

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Functional Description

The CMOD[1:0] bits may be read or written at any time. Disabling the TPM counter by
writing zero to the CMOD[1:0] bits does not affect the TPM counter value or other
registers, but must be acknowledged by the TPM counter clock domain before they read
as zero.
The external clock input passes through a synchronizer clocked by the TPM counter
clock to assure that counter transitions are properly aligned to counter clock transitions.
Therefore, to meet Nyquist criteria considering also jitter, the frequency of the external
clock source must be less than half of the counter clock frequency.

31.4.2 Prescaler
The selected counter clock source passes through a prescaler that is a 7-bit counter. The
value of the prescaler is selected by the PS[2:0] bits. The following figure shows an
example of the prescaler counter and TPM counter.
timer module counting is up.
PS[2:0] = 001
CNTIN = 0x0000

selected input clock

prescaler counter

1

timer module counter

0

0

1
1

0

1
2

0

1

0

3

1
0

0

1
1

0

1
2

0

1
3

0

1
0

0
1

Figure 31-78. Example of the Prescaler Counter

31.4.3 Counter
The TPM has a 16-bit counter that is used by the channels either for input or output
modes. The counter updates from the selected clock divided by the prescaler.
The TPM counter has these modes of operation:
• up counting (see Up Counting)
• up-down counting (see Up-Down Counting)

31.4.3.1 Up Counting
Up counting is selected when (CPWMS = 0)

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Chapter 31 Timer/PWM Module (TPM)

The value of zero is loaded into the TPM counter, and the counter increments until the
value of MOD is reached, at which point the counter is reloaded with zero.
The TPM period when using up counting is (MOD + 0x0001) × period of the TPM
counter clock.
The TOF bit is set when the TPM counter changes from MOD to zero.
MOD = 0x0004
timer module counter

3

4

0

1

2

3

4

0

1

2

3

0

4

1

2

TOF bit
set TOF bit

set TOF bit

set TOF bit

period of timer module counter clock

period of counting = (MOD + 0x0001) x period of timer module counter clock

Figure 31-79. Example of TPM Up Counting

Note
• MOD = 0000 is a redundant condition. In this case, the
TPM counter is always equal to MOD and the TOF bit is
set in each rising edge of the TPM counter clock.

31.4.3.2 Up-Down Counting
Up-down counting is selected when (CPWMS = 1). When configured for up-down
counting, configuring MOD to less than 2 is not supported.
The value of zero is loaded into the TPM counter, and the counter increments until the
value of MOD is reached, at which point the counter is decremented until it returns to
zero and the up-down counting restarts.
The TPM period when using up-down counting is 2 × MOD × period of the TPM counter
clock.
The TOF bit is set when the TPM counter changes from MOD to (MOD – 1).

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Functional Description
MOD = 0x0004
Timer module counter

0

1

2

3

4

3

2

1

0

1

2

3

4

3

2

1

0

1

2

3

4

TOF bit
set TOF bit

set TOF bit

period of timer module counter clock
period of counting = 2 x MOD x period of timer module counter clock

Figure 31-80. Example of Up-Down Counting

31.4.3.3 Counter Reset
Any write to CNT resets the TPM counter and the channel outputs to their initial values
(except for channels in output compare mode).

31.4.4 Input Capture Mode
The input capture mode is selected when (CPWMS = 0), (MSnB:MSnA = 0:0), and
(ELSnB:ELSnA ≠ 0:0).
When a selected edge occurs on the channel input, the current value of the TPM counter
is captured into the CnV register, at the same time the CHnF bit is set and the channel
interrupt is generated if enabled by CHnIE = 1 (see the following figure).
When a channel is configured for input capture, the TPM_CHn pin is an edge-sensitive
input. ELSnB:ELSnA control bits determine which edge, falling or rising, triggers inputcapture event. Note that the maximum frequency for the channel input signal to be
detected correctly is counter clock divided by 4, which is required to meet Nyquist
criteria for signal sampling.
Writes to the CnV register are ignored in input capture mode.

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Chapter 31 Timer/PWM Module (TPM)
was rising
edge selected?

0
synchronizer
channel (n) input

timer module clock

D

Q

CLK

D

rising edge
Q

CLK

0

CHnIE

channel (n) interrupt

CHnF

1

edge
detector

CnV

falling edge
0

1
0

was falling
edge selected?

timer module counter

Figure 31-81. Input capture mode

The CHnF bit is set on the third rising edge of the counter clock after a valid edge occurs
on the channel input.

31.4.5 Output Compare Mode
The output compare mode is selected when (CPWMS = 0), and (MSnB:MSnA = 0:1).
In output compare mode, the TPM can generate timed pulses with programmable
position, polarity, duration, and frequency. When the counter matches the value in the
CnV register of an output compare channel, the channel (n) output can be set, cleared, or
toggled.
When a channel is initially configured to output compare mode, the channel output
updates with its negated value (logic 0 for set/toggle/pulse high and logic one for clear/
pulse low).
The CHnF bit is set and the channel (n) interrupt is generated (if CHnIE = 1) at the
channel (n) match (TPM counter = CnV).

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Functional Description
MOD = 0x0005
CnV = 0x0003
channel (n)
match

counter
overflow
CNT

...

2

1

0

channel (n) output

previous value

CHnF bit

previous value

4

3

channel (n)
match

counter
overflow
5

1

0

2

counter
overflow
4

3

5

1

0

...

TOF bit

Figure 31-82. Example of the output compare mode when the match toggles the channel
output
MOD = 0x0005
CnV = 0x0003

CNT
channel (n) output
CHnF bit

...

0

counter
overflow

channel (n)
match

counter
overflow

2

1

3

4

5

0

counter
overflow

channel (n)
match
1

2

3

4

5

0

1

...

previous value
previous value

TOF bit

Figure 31-83. Example of the output compare mode when the match clears the channel
output
MOD = 0x0005
CnV = 0x0003
channel (n)
match

counter
overflow
CNT
channel (n) output

CHnF bit

...

0

1

2

3

counter
overflow
4

5

0

channel (n)
match
1

2

3

counter
overflow
4

5

0

1

...

previous value
previous value

TOF bit

Figure 31-84. Example of the output compare mode when the match sets the channel
output

It is possible to use the output compare mode with (ELSnB:ELSnA = 0:0). In this case,
when the counter reaches the value in the CnV register, the CHnF bit is set and the
channel (n) interrupt is generated (if CHnIE = 1), however the channel (n) output is not
modified and controlled by TPM.

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Chapter 31 Timer/PWM Module (TPM)

31.4.6 Edge-Aligned PWM (EPWM) Mode
The edge-aligned mode is selected when (CPWMS = 0), and (MSnB:MSnA = 1:0). The
EPWM period is determined by (MOD + 0x0001) and the pulse width (duty cycle) is
determined by CnV.
The CHnF bit is set and the channel (n) interrupt is generated (if CHnIE = 1) at the
channel (n) match (TPM counter = CnV), that is, at the end of the pulse width.
This type of PWM signal is called edge-aligned because the leading edges of all PWM
signals are aligned with the beginning of the period, which is the same for all channels
within an TPM.
counter overflow

counter overflow

counter overflow

period

pulse
width
channel (n) output
channel (n) match

channel (n) match

channel (n) match

Figure 31-85. EPWM period and pulse width with ELSnB:ELSnA = 1:0

If (ELSnB:ELSnA = 0:0) when the counter reaches the value in the CnV register, the
CHnF bit is set and the channel (n) interrupt is generated (if CHnIE = 1), however the
channel (n) output is not controlled by TPM.
If (ELSnB:ELSnA = 1:0), then the channel (n) output is forced high at the counter
overflow (when the zero is loaded into the TPM counter), and it is forced low at the
channel (n) match (TPM counter = CnV) (see the following figure).
MOD = 0x0008
CnV = 0x0005
counter
overflow
CNT

...

0

channel (n)
match
1

2

3

4

5

counter
overflow
6

7

8

0

1

2

...

channel (n) output
CHnF bit

previous value

TOF bit

Figure 31-86. EPWM signal with ELSnB:ELSnA = 1:0

If (ELSnB:ELSnA = X:1), then the channel (n) output is forced low at the counter
overflow (when zero is loaded into the TPM counter), and it is forced high at the channel
(n) match (TPM counter = CnV) (see the following figure).

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Functional Description
MOD = 0x0008
CnV = 0x0005

counter
overflow
CNT

...

0

channel (n)
match
1

2

3

4

5

counter
overflow
6

7

8

0

1

2

...

channel (n) output
CHnF bit

previous value

TOF bit

Figure 31-87. EPWM signal with ELSnB:ELSnA = X:1

If (CnV = 0x0000), then the channel (n) output is a 0% duty cycle EPWM signal. If (CnV
> MOD), then the channel (n) output is a 100% duty cycle EPWM signal and CHnF bit is
not set since there is never a channel (n) match. Therefore, MOD must be less than
0xFFFF in order to get a 100% duty cycle EPWM signal.

31.4.7 Center-Aligned PWM (CPWM) Mode
The center-aligned mode is selected when (CPWMS = 1) and (MSnB:MSnA = 1:0).
The CPWM pulse width (duty cycle) is determined by 2 × CnV and the period is
determined by 2 × MOD (see the following figure). MOD must be kept in the range of
0x0001 to 0x7FFF because values outside this range can produce ambiguous results.
In the CPWM mode, the TPM counter counts up until it reaches MOD and then counts
down until it reaches zero.
The CHnF bit is set and channel (n) interrupt is generated (if CHnIE = 1) at the channel
(n) match (TPM counter = CnV) when the TPM counting is down (at the begin of the
pulse width) and when the TPM counting is up (at the end of the pulse width).
This type of PWM signal is called center-aligned because the pulse width centers for all
channels are when the TPM counter is zero.
The other channel modes are not designed to be used with the up-down counter (CPWMS
= 1). Therefore, all TPM channels should be used in CPWM mode when (CPWMS = 1).

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Chapter 31 Timer/PWM Module (TPM)
timer module counter = 0
channel (n) match
(timer module counting
is down)

counter overflow
timer module counter =
MOD

channel (n) match
counter overflow
(timer module counting timer module counter =
is up)
MOD

channel (n) output
pulse width
(2 x CnV)
period
(2 x MOD)

Figure 31-88. CPWM period and pulse width with ELSnB:ELSnA = 1:0

If (ELSnB:ELSnA = 0:0) when the TPM counter reaches the value in the CnV register,
the CHnF bit is set and the channel (n) interrupt is generated (if CHnIE = 1), however the
channel (n) output is not controlled by TPM.
If (ELSnB:ELSnA = 1:0), then the channel (n) output is forced high at the channel (n)
match (TPM counter = CnV) when counting down, and it is forced low at the channel (n)
match when counting up (see the following figure).
counter
overflow
channel (n) match in
down counting

MOD = 0x0008
CnV = 0x0005

CNT

...

7

8

7

6

5

4

3

counter
overflow
channel (n) match in
down counting

channel (n) match in
up counting

2

1

0

1

2

3

4

5

6

7

8

7

6

5

...

channel (n) output
previous value

CHnF bit
TOF bit

Figure 31-89. CPWM signal with ELSnB:ELSnA = 1:0

If (ELSnB:ELSnA = X:1), then the channel (n) output is forced low at the channel (n)
match (TPM counter = CnV) when counting down, and it is forced high at the channel (n)
match when counting up (see the following figure).
counter
overflow

counter
overflow

MOD = 0x0008
CnV = 0x0005

channel (n) match in
down counting

CNT

...

7

8

7

6

5

4

3

channel (n) match in
up counting

2

1

0

1

2

3

4

5

6

channel (n) match in
down counting

7

8

7

6

5

...

channel (n) output
CHnF bit

previous value

TOF bit

Figure 31-90. CPWM signal with ELSnB:ELSnA = X:1

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Functional Description

If (CnV = 0x0000) then the channel (n) output is a 0% duty cycle CPWM signal.
If (CnV > MOD), then the channel (n) output is a 100% duty cycle CPWM signal,
although the CHnF bit is set when the counter changes from incrementing to
decrementing. Therefore, MOD must be less than 0xFFFF in order to get a 100% duty
cycle CPWM signal.

31.4.8 Registers Updated from Write Buffers
31.4.8.1 MOD Register Update
If (CMOD[1:0] = 0:0) then MOD register is updated when MOD register is written.
If (CMOD[1:0] ≠ 0:0), then MOD register is updated according to the CPWMS bit, that
is:
• If the selected mode is not CPWM then MOD register is updated after MOD register
was written and the TPM counter changes from MOD to zero.
• If the selected mode is CPWM then MOD register is updated after MOD register was
written and the TPM counter changes from MOD to (MOD – 1).

31.4.8.2 CnV Register Update
If (CMOD[1:0] = 0:0) then CnV register is updated when CnV register is written.
If (CMOD[1:0] ≠ 0:0), then CnV register is updated according to the selected mode, that
is:
• If the selected mode is output compare then CnV register is updated on the next TPM
counter increment (end of the prescaler counting) after CnV register was written.
• If the selected mode is EPWM then CnV register is updated after CnV register was
written and the TPM counter changes from MOD to zero.
• If the selected mode is CPWM then CnV register is updated after CnV register was
written and the TPM counter changes from MOD to (MOD – 1).

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Chapter 31 Timer/PWM Module (TPM)

31.4.9 DMA
The channel generates a DMA transfer request according to DMA and CHnIE bits (see
the following table).
Table 31-110. Channel DMA Transfer Request
DMA

CHnIE

Channel DMA Transfer Request

Channel Interrupt

0

0

The channel DMA transfer request is not
generated.

The channel interrupt is not generated.

0

1

The channel DMA transfer request is not
generated.

The channel interrupt is generated if (CHnF = 1).

1

0

The channel DMA transfer request is generated if The channel interrupt is not generated.
(CHnF = 1).

1

1

The channel DMA transfer request is generated if The channel interrupt is generated if (CHnF = 1).
(CHnF = 1).

If DMA = 1, the CHnF bit can be cleared either by channel DMA transfer done or writing
a one to CHnF bit (see the following table).
Table 31-111. Clear CHnF Bit
DMA

How CHnF Bit Can Be Cleared

0

CHnF bit is cleared by writing a 1 to CHnF bit.

1

CHnF bit is cleared either when the channel DMA transfer is done or by writing a 1 to CHnF bit.

31.4.10 Reset Overview
The TPM is reset whenever any chip reset occurs.
When the TPM exits from reset:
• the TPM counter and the prescaler counter are zero and are stopped (CMOD[1:0] =
0:0);
• the timer overflow interrupt is zero;
• the channels interrupts are zero;
• the channels are in input capture mode;
• the channels outputs are zero;
• the channels pins are not controlled by TPM (ELS(n)B:ELS(n)A = 0:0).

31.4.11 TPM Interrupts
This section describes TPM interrupts.
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Functional Description

31.4.11.1 Timer Overflow Interrupt
The timer overflow interrupt is generated when (TOIE = 1) and (TOF = 1).

31.4.11.2 Channel (n) Interrupt
The channel (n) interrupt is generated when (CHnIE = 1) and (CHnF = 1).

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Chapter 32
Periodic Interrupt Timer (PIT)
32.1 Introduction
NOTE
For the chip-specific implementation details of this module's
instances see the chip configuration information.
The PIT module is an array of timers that can be used to raise interrupts and trigger DMA
channels.

32.1.1 Block diagram
The following figure shows the block diagram of the PIT module.

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Signal description
PIT
Peripheral
bus

PIT
registers
load_value

Timer 1

Iinterrupts

Triggers

Timer n
Peripheral
bus clock

Figure 32-1. Block diagram of the PIT

NOTE
See the chip configuration details for the number of PIT
channels used in this MCU.

32.1.2 Features
The main features of this block are:
• Ability of timers to generate DMA trigger pulses
• Ability of timers to generate interrupts
• Maskable interrupts
• Independent timeout periods for each timer

32.2 Signal description
The PIT module has no external pins.

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Chapter 32 Periodic Interrupt Timer (PIT)

32.3 Memory map/register description

This section provides a detailed description of all registers accessible in the PIT module.
NOTE
• Reserved registers will read as 0, writes will have no effect.
• See the chip configuration details for the number of PIT channels used in this MCU.
Table 32-2. Timer Channel n / RTI Channel
Address Offset

Use

Access

Channel + 0x00

Timer Load Value Register

R/W

Channel + 0x04

Current Timer Value Register

R

Channel + 0x08

Timer Control Register

R/W

Channel + 0x0C

Timer Flag Register

R/W

PIT memory map
Absolute
address
(hex)

Register name

Width
Access
(in bits)

Reset value

Section/
page

4003_7000

PIT Module Control Register (PIT_MCR)

32

R/W

0000_0002h

32.3.1/575

4003_70E0

PIT Upper Lifetime Timer Register (PIT_LTMR64H)

32

R

0000_0000h

32.3.2/577

4003_70E4

PIT Lower Lifetime Timer Register (PIT_LTMR64L)

32

R

0000_0000h

32.3.3/577

4003_7100

Timer Load Value Register (PIT_LDVAL0)

32

R/W

0000_0000h

32.3.4/578

4003_7104

Current Timer Value Register (PIT_CVAL0)

32

R

0000_0000h

32.3.5/578

4003_7108

Timer Control Register (PIT_TCTRL0)

32

R/W

0000_0000h

32.3.6/579

4003_710C

Timer Flag Register (PIT_TFLG0)

32

R/W

0000_0000h

32.3.7/580

4003_7110

Timer Load Value Register (PIT_LDVAL1)

32

R/W

0000_0000h

32.3.4/578

4003_7114

Current Timer Value Register (PIT_CVAL1)

32

R

0000_0000h

32.3.5/578

4003_7118

Timer Control Register (PIT_TCTRL1)

32

R/W

0000_0000h

32.3.6/579

4003_711C

Timer Flag Register (PIT_TFLG1)

32

R/W

0000_0000h

32.3.7/580

32.3.1 PIT Module Control Register (PIT_MCR)
This register enables or disables the PIT timer clocks and controls the timers when the
PIT enters the Debug mode.

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Memory map/register description
Address: 4003_7000h base + 0h offset = 4003_7000h
Bit

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

0

R

W

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Bit

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

MDIS

FRZ

1

0

Reserved

Reset

0

R

W

Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

PIT_MCR field descriptions
Field

Description

0–28
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

29
Reserved

This field is reserved.

30
MDIS

Module Disable - (PIT section)
Disables the standard timers. The RTI timer is not affected by this field. This field must be enabled before
any other setup is done.
0
1

31
FRZ

Clock for standard PIT timers is enabled.
Clock for standard PIT timers is disabled.

Freeze
Allows the timers to be stopped when the device enters the Debug mode.
0
1

Timers continue to run in Debug mode.
Timers are stopped in Debug mode.

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Chapter 32 Periodic Interrupt Timer (PIT)

32.3.2 PIT Upper Lifetime Timer Register (PIT_LTMR64H)
This register is intended for applications that chain timer 0 and timer 1 to build a 64-bit
lifetimer.
Address: 4003_7000h base + E0h offset = 4003_70E0h
Bit

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

LTH

R
W
Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

PIT_LTMR64H field descriptions
Field

Description

0–31
LTH

Life Timer value
Shows the timer value of timer 1. If this register is read at a time t1, LTMR64L shows the value of timer 0
at time t1.

32.3.3 PIT Lower Lifetime Timer Register (PIT_LTMR64L)
This register is intended for applications that chain timer 0 and timer 1 to build a 64-bit
lifetimer.
To use LTMR64H and LTMR64L, timer 0 and timer 1 need to be chained. To obtain the
correct value, first read LTMR64H and then LTMR64L. LTMR64H will have the value
of CVAL1 at the time of the first access, LTMR64L will have the value of CVAL0 at the
time of the first access, therefore the application does not need to worry about carry-over
effects of the running counter.
Address: 4003_7000h base + E4h offset = 4003_70E4h
Bit

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

LTL

R
W
Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

PIT_LTMR64L field descriptions
Field
0–31
LTL

Description
Life Timer value
Shows the value of timer 0 at the time LTMR64H was last read. It will only update if LTMR64H is read.

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Memory map/register description

32.3.4 Timer Load Value Register (PIT_LDVALn)
These registers select the timeout period for the timer interrupts.
Address: 4003_7000h base + 100h offset + (16d × i), where i=0d to 1d
Bit
R
W

0

Reset

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

TSV
0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

PIT_LDVALn field descriptions
Field

Description

0–31
TSV

Timer Start Value
Sets the timer start value. The timer will count down until it reaches 0, then it will generate an interrupt and
load this register value again. Writing a new value to this register will not restart the timer; instead the
value will be loaded after the timer expires. To abort the current cycle and start a timer period with the new
value, the timer must be disabled and enabled again.

32.3.5 Current Timer Value Register (PIT_CVALn)
These registers indicate the current timer position.
Address: 4003_7000h base + 104h offset + (16d × i), where i=0d to 1d
Bit

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

TVL

R
W
Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

PIT_CVALn field descriptions
Field
0–31
TVL

Description
Current Timer Value
Represents the current timer value, if the timer is enabled.
NOTE:

• If the timer is disabled, do not use this field as its value is unreliable.
• The timer uses a downcounter. The timer values are frozen in Debug mode if MCR[FRZ] is
set.

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Chapter 32 Periodic Interrupt Timer (PIT)

32.3.6 Timer Control Register (PIT_TCTRLn)
These register contain the control bits for each timer.
Address: 4003_7000h base + 108h offset + (16d × i), where i=0d to 1d
Bit

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

0

R
W

Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Bit

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

CHN

TIE

TEN

0

0

0

0

R
W

Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

PIT_TCTRLn field descriptions
Field
0–28
Reserved
29
CHN

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
Chain Mode
When activated, Timer n-1 needs to expire before timer n can decrement by 1.
Timer 0 can not be changed.
0
1

30
TIE

Timer Interrupt Enable
When an interrupt is pending, or, TFLGn[TIF] is set, enabling the interrupt will immediately cause an
interrupt event. To avoid this, the associated TFLGn[TIF] must be cleared first.
0
1

31
TEN

Timer is not chained.
Timer is chained to previous timer. For example, for Channel 2, if this field is set, Timer 2 is chained to
Timer 1.

Interrupt requests from Timer n are disabled.
Interrupt will be requested whenever TIF is set.

Timer Enable
Enables or disables the timer.
0
1

Timer n is disabled.
Timer n is enabled.

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Functional description

32.3.7 Timer Flag Register (PIT_TFLGn)
These registers hold the PIT interrupt flags.
Address: 4003_7000h base + 10Ch offset + (16d × i), where i=0d to 1d
Bit

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

0

R
W

Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Bit

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

0

R

TIF
w1c

W

Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

PIT_TFLGn field descriptions
Field
0–30
Reserved
31
TIF

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
Timer Interrupt Flag
Sets to 1 at the end of the timer period. Writing 1 to this flag clears it. Writing 0 has no effect. If enabled,
or, when TCTRLn[TIE] = 1, TIF causes an interrupt request.
0
1

Timeout has not yet occurred.
Timeout has occurred.

32.4 Functional description
This section provides the functional description of the module.

32.4.1 General operation
This section gives detailed information on the internal operation of the module. Each
timer can be used to generate trigger pulses and interrupts. Each interrupt is available on
a separate interrupt line.

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Chapter 32 Periodic Interrupt Timer (PIT)

32.4.1.1 Timers
The timers generate triggers at periodic intervals, when enabled. The timers load the start
values as specified in their LDVAL registers, count down to 0 and then load the
respective start value again. Each time a timer reaches 0, it will generate a trigger pulse
and set the interrupt flag.
All interrupts can be enabled or masked by setting TCTRLn[TIE]. A new interrupt can be
generated only after the previous one is cleared.
If desired, the current counter value of the timer can be read via the CVAL registers.
The counter period can be restarted, by first disabling, and then enabling the timer with
TCTRLn[TEN]. See the following figure.
Disable
timer

Timer enabled
Start value = p1

Re-enable
timer

Trigger
event
p1

p1

p1

p1

Figure 32-17. Stopping and starting a timer

The counter period of a running timer can be modified, by first disabling the timer,
setting a new load value, and then enabling the timer again. See the following figure.
Timer enabled
Start value = p1

Trigger
event

Re-enable
Disable timer,
Set new load value timer

p2

p1

p2

p2

p1

Figure 32-18. Modifying running timer period

It is also possible to change the counter period without restarting the timer by writing
LDVAL with the new load value. This value will then be loaded after the next trigger
event. See the following figure.

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Initialization and application information

Timer enabled
Start value = p1

New start
Value p2 set

Trigger
event
p1

p1

p1

p2

p2

Figure 32-19. Dynamically setting a new load value

32.4.1.2 Debug mode
In Debug mode, the timers will be frozen based on MCR[FRZ]. This is intended to aid
software development, allowing the developer to halt the processor, investigate the
current state of the system, for example, the timer values, and then continue the
operation.

32.4.2 Interrupts
All the timers support interrupt generation. See the MCU specification for related vector
addresses and priorities.
Timer interrupts can be enabled by setting TCTRLn[TIE]. TFLGn[TIF] are set to 1 when
a timeout occurs on the associated timer, and are cleared to 0 by writing a 1 to the
corresponding TFLGn[TIF].

32.4.3 Chained timers
When a timer has chain mode enabled, it will only count after the previous timer has
expired. So if timer n-1 has counted down to 0, counter n will decrement the value by
one. This allows to chain some of the timers together to form a longer timer. The first
timer (timer 0) cannot be chained to any other timer.

32.5 Initialization and application information
In the example configuration:
• The PIT clock has a frequency of 50 MHz.

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Chapter 32 Periodic Interrupt Timer (PIT)

• Timer 1 creates an interrupt every 5.12 ms.
• Timer 3 creates a trigger event every 30 ms.
The PIT module must be activated by writing a 0 to MCR[MDIS].
The 50 MHz clock frequency equates to a clock period of 20 ns. Timer 1 needs to trigger
every 5.12 ms/20 ns = 256,000 cycles and Timer 3 every 30 ms/20 ns = 1,500,000 cycles.
The value for the LDVAL register trigger is calculated as:
LDVAL trigger = (period / clock period) -1
This means LDVAL1 and LDVAL3 must be written with 0x0003E7FF and 0x0016E35F
respectively.
The interrupt for Timer 1 is enabled by setting TCTRL1[TIE]. The timer is started by
writing 1 to TCTRL1[TEN].
Timer 3 shall be used only for triggering. Therefore, Timer 3 is started by writing a 1 to
TCTRL3[TEN]. TCTRL3[TIE] stays at 0.
The following example code matches the described setup:
// turn on PIT
PIT_MCR = 0x00;
// Timer 1
PIT_LDVAL1 = 0x0003E7FF; // setup timer 1 for 256000 cycles
PIT_TCTRL1 = TIE; // enable Timer 1 interrupts
PIT_TCTRL1 |= TEN; // start Timer 1
// Timer 3
PIT_LDVAL3 = 0x0016E35F; // setup timer 3for 1500000 cycles
PIT_TCTRL3 |= TEN; // start Timer 3

32.6 Example configuration for chained timers
In the example configuration:
• The PIT clock has a frequency of 100 MHz.
• Timers 1 and 2 are available.
• An interrupt shall be raised every 1 hour.
The PIT module needs to be activated by writing a 0 to MCR[MDIS].

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Example configuration for the lifetime timer

The 100 MHz clock frequency equates to a clock period of 10 ns, so the PIT needs to
count for 6000 million cycles, which is more than a single timer can do. So, Timer 1 is
set up to trigger every 6 s (600 million cycles). Timer 2 is chained to Timer 1 and
programmed to trigger 10 times.
The value for the LDVAL register trigger is calculated as number of cycles-1, so
LDVAL1 receives the value 0x23C345FF and LDVAL2 receives the value 0x00000009.
The interrupt for Timer 2 is enabled by setting TCTRL2[TIE], the Chain mode is
activated by setting TCTRL2[CHN], and the timer is started by writing a 1 to
TCTRL2[TEN]. TCTRL1[TEN] needs to be set, and TCTRL1[CHN] and TCTRL1[TIE]
are cleared.
The following example code matches the described setup:
// turn on PIT
PIT_MCR = 0x00;
// Timer 2
PIT_LDVAL2
PIT_TCTRL2
PIT_TCTRL2
PIT_TCTRL2

= 0x00000009; //
= TIE; // enable
|= CHN; // chain
|= TEN; // start

setup
Timer
Timer
Timer

Timer 2 for 10 counts
2 interrupt
2 to Timer 1
2

// Timer 1
PIT_LDVAL1 = 0x23C345FF; // setup Timer 1 for 600 000 000 cycles
PIT_TCTRL1 = TEN; // start Timer 1

32.7 Example configuration for the lifetime timer
To configure the lifetimer timer, channels 0 and 1 need to be chained together.
First the PIT module needs to be activated by writing a 0 to the MDIS bit in the CTRL
register, then the LDVAL registers need to be set to the maximum value.
The timer is a downcounter.
The following example code matches the described setup:
// turn on PIT
PIT_MCR = 0x00;
// Timer 1
PIT_LDVAL1
PIT_TCTRL1
PIT_TCTRL1
PIT_TCTRL1

= 0xFFFFFFFF; // setup timer 1 for maximum counting period
= 0x0; // disable timer 1 interrupts
|= CHN; // chain timer 1 to timer 0
|= TEN; // start timer 1

// Timer 0

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Chapter 32 Periodic Interrupt Timer (PIT)
PIT_LDVAL0 = 0xFFFFFFFF; // setup timer 0 for maximum counting period
PIT_TCTRL0 = TEN; // start timer 0

To access the lifetime, read first LTMR64H and then LTMR64L.
current_uptime = PIT_LTMR64H<<32;
current_uptime = current_uptime + PIT_LTMR64L;

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Example configuration for the lifetime timer

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Chapter 33
Low-Power Timer (LPTMR)
33.1 Introduction
NOTE
For the chip-specific implementation details of this module's
instances see the chip configuration information.
The low-power timer (LPTMR) can be configured to operate as a time counter with
optional prescaler, or as a pulse counter with optional glitch filter, across all power
modes, including the low-leakage modes. It can also continue operating through most
system reset events, allowing it to be used as a time of day counter.

33.1.1 Features
The features of the LPTMR module include:
• 16-bit time counter or pulse counter with compare
• Optional interrupt can generate asynchronous wakeup from any low-power mode
• Hardware trigger output
• Counter supports free-running mode or reset on compare
• Configurable clock source for prescaler/glitch filter
• Configurable input source for pulse counter
• Rising-edge or falling-edge

33.1.2 Modes of operation
The following table describes the operation of the LPTMR module in various modes.

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LPTMR signal descriptions

Table 33-1. Modes of operation
Modes

Description

Run

The LPTMR operates normally.

Wait

The LPTMR continues to operate normally and
may be configured to exit the low-power mode
by generating an interrupt request.

Stop

The LPTMR continues to operate normally and
may be configured to exit the low-power mode
by generating an interrupt request.

Low-Leakage

The LPTMR continues to operate normally and
may be configured to exit the low-power mode
by generating an interrupt request.

Debug

The LPTMR operates normally in Pulse Counter
mode, but counter does not increment in Time
Counter mode.

33.2 LPTMR signal descriptions

Table 33-2. LPTMR signal descriptions

Signal

I/O

LPTMR_ALTn

I

Description
Pulse Counter Input pin

33.2.1 Detailed signal descriptions
Table 33-3. LPTMR interface—detailed signal descriptions
Signal

I/O

LPTMR_ALTn

I

Description
Pulse Counter Input
The LPTMR can select one of the input pins to be used in Pulse Counter mode.
State meaning

Assertion—If configured for pulse counter mode with
active-high input, then assertion causes the CNR to
increment.
Deassertion—If configured for pulse counter mode with
active-low input, then deassertion causes the CNR to
increment.

Timing

Assertion or deassertion may occur at any time; input may
assert asynchronously to the bus clock.

33.3 Memory map and register definition
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Chapter 33 Low-Power Timer (LPTMR)

LPTMR memory map
Absolute
address
(hex)

Width
Access
(in bits)

Register name

Reset value

Section/
page

4004_0000

Low Power Timer Control Status Register (LPTMR0_CSR)

32

R/W

0000_0000h

33.3.1/589

4004_0004

Low Power Timer Prescale Register (LPTMR0_PSR)

32

R/W

0000_0000h

33.3.2/590

4004_0008

Low Power Timer Compare Register (LPTMR0_CMR)

32

R/W

0000_0000h

33.3.3/592

4004_000C

Low Power Timer Counter Register (LPTMR0_CNR)

32

R

0000_0000h

33.3.4/592

33.3.1 Low Power Timer Control Status Register (LPTMRx_CSR)
Address: 4004_0000h base + 0h offset = 4004_0000h
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

0

R
W

Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Bit

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

TPP

TFC

TMS

TEN

0

0

0

0

0

R

TCF
w1c

W

Reset

0

0

0

0

0

0

0

0

0

TIE
0

TPS
0

0

LPTMRx_CSR field descriptions
Field
31–8
Reserved
7
TCF

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
Timer Compare Flag
TCF is set when the LPTMR is enabled and the CNR equals the CMR and increments. TCF is cleared
when the LPTMR is disabled or a logic 1 is written to it.
0
1

6
TIE

Timer Interrupt Enable
When TIE is set, the LPTMR Interrupt is generated whenever TCF is also set.
0
1

5–4
TPS

The value of CNR is not equal to CMR and increments.
The value of CNR is equal to CMR and increments.

Timer interrupt disabled.
Timer interrupt enabled.

Timer Pin Select
Configures the input source to be used in Pulse Counter mode. TPS must be altered only when the
LPTMR is disabled. The input connections vary by device. See the chip configuration details for
information on the connections to these inputs.
00

Pulse counter input 0 is selected.
Table continues on the next page...

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Memory map and register definition

LPTMRx_CSR field descriptions (continued)
Field

Description
01
10
11

3
TPP

Pulse counter input 1 is selected.
Pulse counter input 2 is selected.
Pulse counter input 3 is selected.

Timer Pin Polarity
Configures the polarity of the input source in Pulse Counter mode. TPP must be changed only when the
LPTMR is disabled.
0
1

2
TFC

Pulse Counter input source is active-high, and the CNR will increment on the rising-edge.
Pulse Counter input source is active-low, and the CNR will increment on the falling-edge.

Timer Free-Running Counter
When clear, TFC configures the CNR to reset whenever TCF is set. When set, TFC configures the CNR to
reset on overflow. TFC must be altered only when the LPTMR is disabled.
0
1

1
TMS

CNR is reset whenever TCF is set.
CNR is reset on overflow.

Timer Mode Select
Configures the mode of the LPTMR. TMS must be altered only when the LPTMR is disabled.
0
1

0
TEN

Time Counter mode.
Pulse Counter mode.

Timer Enable
When TEN is clear, it resets the LPTMR internal logic, including the CNR and TCF. When TEN is set, the
LPTMR is enabled. While writing 1 to this field, CSR[5:1] must not be altered.
0
1

LPTMR is disabled and internal logic is reset.
LPTMR is enabled.

33.3.2 Low Power Timer Prescale Register (LPTMRx_PSR)
Address: 4004_0000h base + 4h offset = 4004_0004h
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

0

R
W

Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Bit

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

R

PRESCALE

W

Reset

0

0

0

0

0

0

0

0

0

0

0

PBYP

0

0

0

PCS
0

0

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Chapter 33 Low-Power Timer (LPTMR)

LPTMRx_PSR field descriptions
Field
31–7
Reserved
6–3
PRESCALE

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
Prescale Value
Configures the size of the Prescaler in Time Counter mode or width of the glitch filter in Pulse Counter
mode. PRESCALE must be altered only when the LPTMR is disabled.
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111

2
PBYP

Prescaler Bypass
When PBYP is set, the selected prescaler clock in Time Counter mode or selected input source in Pulse
Counter mode directly clocks the CNR. When PBYP is clear, the CNR is clocked by the output of the
prescaler/glitch filter. PBYP must be altered only when the LPTMR is disabled.
0
1

1–0
PCS

Prescaler divides the prescaler clock by 2; glitch filter does not support this configuration.
Prescaler divides the prescaler clock by 4; glitch filter recognizes change on input pin after 2 rising
clock edges.
Prescaler divides the prescaler clock by 8; glitch filter recognizes change on input pin after 4 rising
clock edges.
Prescaler divides the prescaler clock by 16; glitch filter recognizes change on input pin after 8
rising clock edges.
Prescaler divides the prescaler clock by 32; glitch filter recognizes change on input pin after 16
rising clock edges.
Prescaler divides the prescaler clock by 64; glitch filter recognizes change on input pin after 32
rising clock edges.
Prescaler divides the prescaler clock by 128; glitch filter recognizes change on input pin after 64
rising clock edges.
Prescaler divides the prescaler clock by 256; glitch filter recognizes change on input pin after 128
rising clock edges.
Prescaler divides the prescaler clock by 512; glitch filter recognizes change on input pin after 256
rising clock edges.
Prescaler divides the prescaler clock by 1024; glitch filter recognizes change on input pin after 512
rising clock edges.
Prescaler divides the prescaler clock by 2048; glitch filter recognizes change on input pin after
1024 rising clock edges.
Prescaler divides the prescaler clock by 4096; glitch filter recognizes change on input pin after
2048 rising clock edges.
Prescaler divides the prescaler clock by 8192; glitch filter recognizes change on input pin after
4096 rising clock edges.
Prescaler divides the prescaler clock by 16,384; glitch filter recognizes change on input pin after
8192 rising clock edges.
Prescaler divides the prescaler clock by 32,768; glitch filter recognizes change on input pin after
16,384 rising clock edges.
Prescaler divides the prescaler clock by 65,536; glitch filter recognizes change on input pin after
32,768 rising clock edges.

Prescaler/glitch filter is enabled.
Prescaler/glitch filter is bypassed.

Prescaler Clock Select
Selects the clock to be used by the LPTMR prescaler/glitch filter. PCS must be altered only when the
LPTMR is disabled. The clock connections vary by device.
NOTE: See the chip configuration details for information on the connections to these inputs.
Table continues on the next page...

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Memory map and register definition

LPTMRx_PSR field descriptions (continued)
Field

Description
00
01
10
11

Prescaler/glitch filter clock 0 selected.
Prescaler/glitch filter clock 1 selected.
Prescaler/glitch filter clock 2 selected.
Prescaler/glitch filter clock 3 selected.

33.3.3 Low Power Timer Compare Register (LPTMRx_CMR)
Address: 4004_0000h base + 8h offset = 4004_0008h
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

0

R

0

0

0

0

0

0

0

0

8

7

6

5

4

3

2

1

0

0

0

0

0

0

0

COMPARE

W
Reset

9

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

LPTMRx_CMR field descriptions
Field

Description

31–16
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

15–0
COMPARE

Compare Value
When the LPTMR is enabled and the CNR equals the value in the CMR and increments, TCF is set and
the hardware trigger asserts until the next time the CNR increments. If the CMR is 0, the hardware trigger
will remain asserted until the LPTMR is disabled. If the LPTMR is enabled, the CMR must be altered only
when TCF is set.

33.3.4 Low Power Timer Counter Register (LPTMRx_CNR)
Address: 4004_0000h base + Ch offset = 4004_000Ch
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

0

R

9

8

7

6

5

4

3

2

1

0

0

0

0

0

0

0

COUNTER

W
Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

LPTMRx_CNR field descriptions
Field
31–16
Reserved
15–0
COUNTER

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
Counter Value

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Chapter 33 Low-Power Timer (LPTMR)

33.4 Functional description
33.4.1 LPTMR power and reset
The LPTMR remains powered in all power modes, including low-leakage modes. If the
LPTMR is not required to remain operating during a low-power mode, then it must be
disabled before entering the mode.
The LPTMR is reset only on global Power On Reset (POR) or Low Voltage Detect
(LVD). When configuring the LPTMR registers, the CSR must be initially written with
the timer disabled, before configuring the PSR and CMR. Then, CSR[TIE] must be set as
the last step in the initialization. This ensures the LPTMR is configured correctly and the
LPTMR counter is reset to zero following a warm reset.

33.4.2 LPTMR clocking
The LPTMR prescaler/glitch filter can be clocked by one of the four clocks. The clock
source must be enabled before the LPTMR is enabled.
NOTE
The clock source selected may need to be configured to remain
enabled in low-power modes, otherwise the LPTMR will not
operate during low-power modes.
In Pulse Counter mode with the prescaler/glitch filter bypassed, the selected input source
directly clocks the CNR and no other clock source is required. To minimize power in this
case, configure the prescaler clock source for a clock that is not toggling.
NOTE
The clock source or pulse input source selected for the LPTMR
should not exceed the frequency fLPTMR defined in the device
datasheet.

33.4.3 LPTMR prescaler/glitch filter
The LPTMR prescaler and glitch filter share the same logic which operates as a prescaler
in Time Counter mode and as a glitch filter in Pulse Counter mode.

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Functional description

NOTE
The prescaler/glitch filter configuration must not be altered
when the LPTMR is enabled.

33.4.3.1 Prescaler enabled
In Time Counter mode, when the prescaler is enabled, the output of the prescaler directly
clocks the CNR. When the LPTMR is enabled, the CNR will increment every 22 to 216
prescaler clock cycles. After the LPTMR is enabled, the first increment of the CNR will
take an additional one or two prescaler clock cycles due to synchronization logic.

33.4.3.2 Prescaler bypassed
In Time Counter mode, when the prescaler is bypassed, the selected prescaler clock
increments the CNR on every clock cycle. When the LPTMR is enabled, the first
increment will take an additional one or two prescaler clock cycles due to
synchronization logic.

33.4.3.3 Glitch filter
In Pulse Counter mode, when the glitch filter is enabled, the output of the glitch filter
directly clocks the CNR. When the LPTMR is first enabled, the output of the glitch filter
is asserted, that is, logic 1 for active-high and logic 0 for active-low. The following table
shows the change in glitch filter output with the selected input source.
If
The selected input source remains deasserted for at least
to 215 consecutive prescaler clock rising edges

Then
21

The selected input source remains asserted for at least 21 to
215 consecutive prescaler clock rising-edges

The glitch filter output will also deassert.
The glitch filter output will also assert.

NOTE
The input is only sampled on the rising clock edge.
The CNR will increment each time the glitch filter output asserts. In Pulse Counter mode,
the maximum rate at which the CNR can increment is once every 22 to 216 prescaler
clock edges. When first enabled, the glitch filter will wait an additional one or two
prescaler clock edges due to synchronization logic.

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Chapter 33 Low-Power Timer (LPTMR)

33.4.3.4 Glitch filter bypassed
In Pulse Counter mode, when the glitch filter is bypassed, the selected input source
increments the CNR every time it asserts. Before the LPTMR is first enabled, the selected
input source is forced to be asserted. This prevents the CNR from incrementing if the
selected input source is already asserted when the LPTMR is first enabled.

33.4.4 LPTMR compare
When the CNR equals the value of the CMR and increments, the following events occur:
•
•
•
•

CSR[TCF] is set.
LPTMR interrupt is generated if CSR[TIE] is also set.
LPTMR hardware trigger is generated.
CNR is reset if CSR[TFC] is clear.

When the LPTMR is enabled, the CMR can be altered only when CSR[TCF] is set. When
updating the CMR, the CMR must be written and CSR[TCF] must be cleared before the
LPTMR counter has incremented past the new LPTMR compare value.

33.4.5 LPTMR counter
The CNR increments by one on every:
•
•
•
•

Prescaler clock in Time Counter mode with prescaler bypassed
Prescaler output in Time Counter mode with prescaler enabled
Input source assertion in Pulse Counter mode with glitch filter bypassed
Glitch filter output in Pulse Counter mode with glitch filter enabled

The CNR is reset when the LPTMR is disabled or if the counter register overflows. If
CSR[TFC] is cleared, then the CNR is also reset whenever CSR[TCF] is set.
The CNR continues incrementing when the core is halted in Debug mode when
configured for Pulse Counter mode, the CNR will stop incrementing when the core is
halted in Debug mode when configured for Time Counter mode.
The CNR cannot be initialized, but can be read at any time. On each read of the CNR,
software must first write to the CNR with any value. This will synchronize and register
the current value of the CNR into a temporary register. The contents of the temporary
register are returned on each read of the CNR.
When reading the CNR, the bus clock must be at least two times faster than the rate at
which the LPTMR counter is incrementing, otherwise incorrect data may be returned.
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Functional description

33.4.6 LPTMR hardware trigger
The LPTMR hardware trigger asserts at the same time the CSR[TCF] is set and can be
used to trigger hardware events in other peripherals without software intervention. The
hardware trigger is always enabled.
When

Then

The CMR is set to 0 with CSR[TFC] clear

The LPTMR hardware trigger will assert on the first compare
and does not deassert.

The CMR is set to a nonzero value, or, if CSR[TFC] is set

The LPTMR hardware trigger will assert on each compare
and deassert on the following increment of the CNR.

33.4.7 LPTMR interrupt
The LPTMR interrupt is generated whenever CSR[TIE] and CSR[TCF] are set.
CSR[TCF] is cleared by disabling the LPTMR or by writing a logic 1 to it.
CSR[TIE] can be altered and CSR[TCF] can be cleared while the LPTMR is enabled.
The LPTMR interrupt is generated asynchronously to the system clock and can be used to
generate a wakeup from any low-power mode, including the low-leakage modes,
provided the LPTMR is enabled as a wakeup source.

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Chapter 34
Real Time Clock (RTC)
34.1 Introduction
NOTE
For the chip-specific implementation details of this module's
instances see the chip configuration information.

34.1.1 Features
The RTC module features include:
• 32-bit seconds counter with roll-over protection and 32-bit alarm
• 16-bit prescaler with compensation that can correct errors between 0.12 ppm and
3906 ppm
• Register write protection
• Lock register requires POR or software reset to enable write access
• 1 Hz square wave output

34.1.2 Modes of operation
The RTC remains functional in all low power modes and can generate an interrupt to exit
any low power mode.

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Register definition

34.1.3 RTC Signal Descriptions
Table 34-1. RTC signal descriptions
Signal

Description

RTC_CLKOUT

I/O

1 Hz square-wave output

O

34.1.3.1 RTC clock output
The clock to the seconds counter is available on the RTC_CLKOUT signal. It is a 1 Hz
square wave output.

34.2 Register definition
All registers must be accessed using 32-bit writes and all register accesses incur three
wait states.
Write accesses to any register by non-supervisor mode software, when the supervisor
access bit in the control register is clear, will terminate with a bus error.
Read accesses by non-supervisor mode software complete as normal.
Writing to a register protected by the lock register does not generate a bus error, but the
write will not complete.
RTC memory map
Absolute
address
(hex)

Register name

Width
Access
(in bits)

Reset value

Section/
page

4003_D000

RTC Time Seconds Register (RTC_TSR)

32

R/W

0000_0000h

34.2.1/599

4003_D004

RTC Time Prescaler Register (RTC_TPR)

32

R/W

0000_0000h

34.2.2/599

4003_D008

RTC Time Alarm Register (RTC_TAR)

32

R/W

0000_0000h

34.2.3/600

4003_D00C RTC Time Compensation Register (RTC_TCR)

32

R/W

0000_0000h

34.2.4/600

4003_D010

RTC Control Register (RTC_CR)

32

R/W

0000_0000h

34.2.5/601

4003_D014

RTC Status Register (RTC_SR)

32

R/W

0000_0001h

34.2.6/603

4003_D018

RTC Lock Register (RTC_LR)

32

R/W

0000_00FFh

34.2.7/604

32

R/W

0000_0007h

34.2.8/605

4003_D01C RTC Interrupt Enable Register (RTC_IER)

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Chapter 34 Real Time Clock (RTC)

34.2.1 RTC Time Seconds Register (RTC_TSR)
Address: 4003_D000h base + 0h offset = 4003_D000h
Bit
R
W

31

Reset

0

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

TSR
0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

RTC_TSR field descriptions
Field

Description

31–0
TSR

Time Seconds Register
When the time counter is enabled, the TSR is read only and increments once a second provided SR[TOF]
or SR[TIF] are not set. The time counter will read as zero when SR[TOF] or SR[TIF] are set. When the
time counter is disabled, the TSR can be read or written. Writing to the TSR when the time counter is
disabled will clear the SR[TOF] and/or the SR[TIF]. Writing to TSR with zero is supported, but not
recommended because TSR will read as zero when SR[TIF] or SR[TOF] are set (indicating the time is
invalid).

34.2.2 RTC Time Prescaler Register (RTC_TPR)
Address: 4003_D000h base + 4h offset = 4003_D004h
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

0

R

0

0

0

0

0

0

0

0

7

6

5

4

3

2

1

0

0

0

0

0

0

0

0

TPR

W
Reset

8

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

RTC_TPR field descriptions
Field
31–16
Reserved
15–0
TPR

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
Time Prescaler Register
When the time counter is enabled, the TPR is read only and increments every 32.768 kHz clock cycle. The
time counter will read as zero when SR[TOF] or SR[TIF] are set. When the time counter is disabled, the
TPR can be read or written. The TSR[TSR] increments when bit 14 of the TPR transitions from a logic one
to a logic zero.

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34.2.3 RTC Time Alarm Register (RTC_TAR)
Address: 4003_D000h base + 8h offset = 4003_D008h
Bit
R
W

31

Reset

0

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

TAR
0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

RTC_TAR field descriptions
Field

Description

31–0
TAR

Time Alarm Register
When the time counter is enabled, the SR[TAF] is set whenever the TAR[TAR] equals the TSR[TSR] and
the TSR[TSR] increments. Writing to the TAR clears the SR[TAF].

34.2.4 RTC Time Compensation Register (RTC_TCR)
Address: 4003_D000h base + Ch offset = 4003_D00Ch
Bit

31

30

29

28

27

26

25

24

23

22

21

20

CIC

R

19

18

17

16

15

14

13

TCV

0

0

0

0

0

0

0

0

0

0

0

0

0

11

10

9

8

7

6

5

CIR

W
Reset

12

0

0

0

0

0

0

0

0

4

3

2

1

0

0

0

0

TCR
0

0

0

0

0

0

0

0

RTC_TCR field descriptions
Field

Description

31–24
CIC

Compensation Interval Counter

23–16
TCV

Time Compensation Value

15–8
CIR

Compensation Interval Register

7–0
TCR

Time Compensation Register

Current value of the compensation interval counter. If the compensation interval counter equals zero then
it is loaded with the contents of the CIR. If the CIC does not equal zero then it is decremented once a
second.

Current value used by the compensation logic for the present second interval. Updated once a second if
the CIC equals 0 with the contents of the TCR field. If the CIC does not equal zero then it is loaded with
zero (compensation is not enabled for that second increment).

Configures the compensation interval in seconds from 1 to 256 to control how frequently the TCR should
adjust the number of 32.768 kHz cycles in each second. The value written should be one less than the
number of seconds. For example, write zero to configure for a compensation interval of one second. This
register is double buffered and writes do not take affect until the end of the current compensation interval.

Configures the number of 32.768 kHz clock cycles in each second. This register is double buffered and
writes do not take affect until the end of the current compensation interval.
Table continues on the next page...

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Chapter 34 Real Time Clock (RTC)

RTC_TCR field descriptions (continued)
Field

Description
80h
...
FFh
00h
01h
...
7Fh

Time Prescaler Register overflows every 32896 clock cycles.
...
Time Prescaler Register overflows every 32769 clock cycles.
Time Prescaler Register overflows every 32768 clock cycles.
Time Prescaler Register overflows every 32767 clock cycles.
...
Time Prescaler Register overflows every 32641 clock cycles.

34.2.5 RTC Control Register (RTC_CR)
Address: 4003_D000h base + 10h offset = 4003_D010h
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

0

R

Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Bit

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

R

0

Reserved

W

UM

SUP

0

0

OSCE

0

0

0

WPE SWR

0

W

Reset

CLKO

SC2P SC4P SC8P

SC16P

0

0

0

0

0

0

0

0

0

0

0

0

RTC_CR field descriptions
Field
31–15
Reserved

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
Table continues on the next page...

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RTC_CR field descriptions (continued)
Field

Description

14
Reserved

This field is reserved.
It must always be written to 0.

13
SC2P

Oscillator 2pF Load Configure

12
SC4P

Oscillator 4pF Load Configure

11
SC8P

Oscillator 8pF Load Configure

10
SC16P

Oscillator 16pF Load Configure

9
CLKO

Clock Output

8
OSCE

Oscillator Enable

7–4
Reserved
3
UM

0
1

0
1

0
1

0
1

0
1

0
1

Disable the load.
Enable the additional load.

Disable the load.
Enable the additional load.

Disable the load.
Enable the additional load.

Disable the load.
Enable the additional load.

The 32 kHz clock is output to other peripherals.
The 32 kHz clock is not output to other peripherals.

32.768 kHz oscillator is disabled.
32.768 kHz oscillator is enabled. After setting this bit, wait the oscillator startup time before enabling
the time counter to allow the 32.768 kHz clock time to stabilize.

This field is reserved.
This read-only field is reserved and always has the value 0.
Update Mode
Allows SR[TCE] to be written even when the Status Register is locked. When set, the SR[TCE] can always
be written if the SR[TIF] or SR[TOF] are set or if the SR[TCE] is clear.
0
1

Registers cannot be written when locked.
Registers can be written when locked under limited conditions.

2
SUP

Supervisor Access

1
WPE

Wakeup Pin Enable

0
1

The wakeup pin is optional and not available on all devices.
0
1

0
SWR

Non-supervisor mode write accesses are not supported and generate a bus error.
Non-supervisor mode write accesses are supported.

Wakeup pin is disabled.
Wakeup pin is enabled and wakeup pin asserts if the RTC interrupt asserts or the wakeup pin is
turned on.

Software Reset
Table continues on the next page...

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Chapter 34 Real Time Clock (RTC)

RTC_CR field descriptions (continued)
Field

Description
0
1

No effect.
Resets all RTC registers except for the SWR bit . The SWR bit is cleared by POR and by software
explicitly clearing it.

34.2.6 RTC Status Register (RTC_SR)
Address: 4003_D000h base + 14h offset = 4003_D014h
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

0

R
W

Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Bit

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

TAF

TOF

TIF

0

0

0

1

0

R

TCE

W

Reset

0

0

0

0

0

0

0

0

0

0

0

0

RTC_SR field descriptions
Field
31–5
Reserved
4
TCE

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
Time Counter Enable
When time counter is disabled the TSR register and TPR register are writeable, but do not increment.
When time counter is enabled the TSR register and TPR register are not writeable, but increment.
0
1

3
Reserved
2
TAF

This field is reserved.
This read-only field is reserved and always has the value 0.
Time Alarm Flag
Time alarm flag is set when the TAR[TAR] equals the TSR[TSR] and the TSR[TSR] increments. This bit is
cleared by writing the TAR register.
0
1

1
TOF

Time counter is disabled.
Time counter is enabled.

Time alarm has not occurred.
Time alarm has occurred.

Time Overflow Flag
Time overflow flag is set when the time counter is enabled and overflows. The TSR and TPR do not
increment and read as zero when this bit is set. This bit is cleared by writing the TSR register when the
time counter is disabled.
0
1

Time overflow has not occurred.
Time overflow has occurred and time counter is read as zero.
Table continues on the next page...

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RTC_SR field descriptions (continued)
Field

Description

0
TIF

Time Invalid Flag
The time invalid flag is set on POR or software reset. The TSR and TPR do not increment and read as
zero when this bit is set. This bit is cleared by writing the TSR register when the time counter is disabled.
0
1

Time is valid.
Time is invalid and time counter is read as zero.

34.2.7 RTC Lock Register (RTC_LR)
Address: 4003_D000h base + 18h offset = 4003_D018h
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

0

0

0

0

0

0

0

0

7

6

5

4

3

2

1

0

0

R
W

Reset

0

0

0

0

Bit

15

14

13

12

0

0

0

0

11

10

9

8

0

R

1

LRL

SRL

CRL

TCL

1

1

1

1

1

W

Reset

0

0

0

0

0

0

0

0

1
1

1

1

RTC_LR field descriptions
Field

Description

31–8
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

7
Reserved

This field is reserved.
This read-only field is reserved and always has the value 1.

6
LRL

Lock Register Lock
After being cleared, this bit can be set only by POR or software reset.
0
1

5
SRL

Status Register Lock
After being cleared, this bit can be set only by POR or software reset.
0
1

4
CRL

Lock Register is locked and writes are ignored.
Lock Register is not locked and writes complete as normal.

Status Register is locked and writes are ignored.
Status Register is not locked and writes complete as normal.

Control Register Lock
After being cleared, this bit can only be set by POR.
0
1

Control Register is locked and writes are ignored.
Control Register is not locked and writes complete as normal.
Table continues on the next page...

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Chapter 34 Real Time Clock (RTC)

RTC_LR field descriptions (continued)
Field

Description

3
TCL

Time Compensation Lock
After being cleared, this bit can be set only by POR or software reset.
0
1

2–0
Reserved

Time Compensation Register is locked and writes are ignored.
Time Compensation Register is not locked and writes complete as normal.

This field is reserved.
This read-only field is reserved and always has the value 1.

34.2.8 RTC Interrupt Enable Register (RTC_IER)
Address: 4003_D000h base + 1Ch offset = 4003_D01Ch
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

0

R

Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Bit

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

TSIE

Reserved

W

TAIE

TOIE

TIIE

0

0

1

1

1

WPON

0

R

W

Reset

0

0

0

0

0

0

0

0

0

Reserved

0

0

RTC_IER field descriptions
Field
31–8
Reserved
7
WPON

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
Wakeup Pin On
The wakeup pin is optional and not available on all devices. Whenever the wakeup pin is enabled and this
bit is set, the wakeup pin will assert.
0
1

6–5
Reserved
4
TSIE

No effect.
If the wakeup pin is enabled, then the wakeup pin will assert.

This field is reserved.
Time Seconds Interrupt Enable
The seconds interrupt is an edge-sensitive interrupt with a dedicated interrupt vector. It is generated once
a second and requires no software overhead (there is no corresponding status flag to clear).
Table continues on the next page...

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RTC_IER field descriptions (continued)
Field

Description
0
1

3
Reserved

Seconds interrupt is disabled.
Seconds interrupt is enabled.

This field is reserved.

2
TAIE

Time Alarm Interrupt Enable

1
TOIE

Time Overflow Interrupt Enable

0
TIIE

Time Invalid Interrupt Enable

0
1

0
1

0
1

Time alarm flag does not generate an interrupt.
Time alarm flag does generate an interrupt.

Time overflow flag does not generate an interrupt.
Time overflow flag does generate an interrupt.

Time invalid flag does not generate an interrupt.
Time invalid flag does generate an interrupt.

34.3 Functional description
34.3.1 Power, clocking, and reset
The RTC is an always powered block that remains active in all low power modes.
The time counter within the RTC is clocked by a 32.768 kHz clock sourced from an
external crystal using the oscillator.
The power-on-reset signal initializes all RTC registers to their default state. A software
reset bit can also initialize all RTC registers.

34.3.1.1 Oscillator control
The 32.768 kHz crystal oscillator is disabled at POR and must be enabled by software.
After enabling the cystal oscillator, wait the oscillator startup time before setting
SR[TCE] or using the oscillator clock external to the RTC.
The crystal oscillator includes tunable capacitors that can be configured by software. Do
not change the capacitance unless the oscillator is disabled.

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Chapter 34 Real Time Clock (RTC)

34.3.1.2 Software reset
Writing one to the CR[SWR] forces the equivalent of a POR to the rest of the RTC
module. The CR[SWR] is not affected by the software reset and must be cleared by
software.

34.3.1.3 Supervisor access
When the supervisor access control bit is clear, only supervisor mode software can write
to the RTC registers, non-supervisor mode software will generate a bus error. Both
supervisor and non-supervisor mode software can always read the RTC registers.

34.3.2 Time counter
The time counter consists of a 32-bit seconds counter that increments once every second
and a 16-bit prescaler register that increments once every 32.768 kHz clock cycle.
The time seconds register and time prescaler register can be written only when SR[TCE]
is clear. Always write to the prescaler register before writing to the seconds register,
because the seconds register increments on the falling edge of bit 14 of the prescaler
register.
The time prescaler register increments provided SR[TCE] is set, SR[TIF] is clear,
SR[TOF] is clear, and the 32.768 kHz clock source is present. After enabling the
oscillator, wait the oscillator startup time before setting SR[TCE] to allow time for the
oscillator clock output to stabilize.
If the time seconds register overflows then the SR[TOF] will set and the time prescaler
register will stop incrementing. Clear SR[TOF] by initializing the time seconds register.
The time seconds register and time prescaler register read as zero whenever SR[TOF] is
set.
SR[TIF] is set on POR and software reset and is cleared by initializing the time seconds
register. The time seconds register and time prescaler register read as zero whenever
SR[TIF] is set.

34.3.3 Compensation
The compensation logic provides an accurate and wide compensation range and can
correct errors as high as 3906 ppm and as low as 0.12 ppm. The compensation factor
must be calculated externally to the RTC and supplied by software to the compensation
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Functional description

register. The RTC itself does not calculate the amount of compensation that is required,
although the 1 Hz clock is output to an external pin in support of external calibration
logic.
Crystal compensation can be supported by using firmware and crystal characteristics to
determine the compensation amount. Temperature compensation can be supported by
firmware that periodically measures the external temperature via ADC and updates the
compensation register based on a look-up table that specifies the change in crystal
frequency over temperature.
The compensation logic alters the number of 32.768 kHz clock cycles it takes for the
prescaler register to overflow and increment the time seconds counter. The time
compensation value is used to adjust the number of clock cycles between -127 and +128.
Cycles are added or subtracted from the prescaler register when the prescaler register
equals 0x3FFF and then increments. The compensation interval is used to adjust the
frequency at which the time compensation value is used, that is, from once a second to
once every 256 seconds.
Updates to the time compensation register will not take effect until the next time the time
seconds register increments and provided the previous compensation interval has expired.
When the compensation interval is set to other than once a second then the compensation
is applied in the first second interval and the remaining second intervals receive no
compensation.
Compensation is disabled by configuring the time compensation register to zero.

34.3.4 Time alarm
The time alarm register, SR[TAF], and IER[TAIE] allow the RTC to generate an
interrupt at a predefined time. The 32-bit time alarm register is compared with the 32-bit
time seconds register each time it increments. The SR[TAF] will set when the time alarm
register equals the time seconds register and the time seconds register increments.
The time alarm flag is cleared by writing the time alarm register. This will usually be the
next alarm value, although writing a value that is less than the time seconds register, such
as zero, will prevent the time alarm flag from setting again. The time alarm flag cannot
otherwise be disabled, although the interrupt it generates is enabled or disabled by
IER[TAIE].

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Chapter 34 Real Time Clock (RTC)

34.3.5 Update mode
The Update Mode bit in the Control register (CR[UM]) configures software write access
to the Time Counter Enable (SR[TCE]) bit. When CR[UM] is clear, SR[TCE] can be
written only when the LR[SRL] bit is set. When CR[UM] is set, the SR[TCE] can also be
written when SR[TCE] is clear or when SR[TIF] or SR[TOF] are set. This allows the
time seconds and prescaler registers to be initialized whenever time is invalidated, while
preventing the time seconds and prescaler registers from being changed on the fly. When
LR[SRL] is set, CR[UM] has no effect on SR[TCE].

34.3.6 Register lock
The lock register can be used to block write accesses to certain registers until the next
POR or software reset. Locking the control register will disable the software reset.
Locking the lock register will block future updates to the lock register.
Write accesses to a locked register are ignored and do not generate a bus error.

34.3.7 Interrupt
The RTC interrupt is asserted whenever a status flag and the corresponding interrupt
enable bit are both set. It is always asserted on POR, and software reset. The RTC
interrupt is enabled at the chip level by enabling the chip-specific RTC clock gate control
bit. The RTC interrupt can be used to wakeup the chip from any low-power mode.
The optional RTC seconds interrupt is an edge-sensitive interrupt with a dedicated
interrupt vector that is generated once a second and requires no software overhead (there
is no corresponding status flag to clear). It is enabled in the RTC by the time seconds
interrupt enable bit and enabled at the chip level by setting the chip-specific RTC clock
gate control bit. This interrupt is optional and may not be implemented on all devices.

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Chapter 35
Universal Serial Bus OTG Controller (USBOTG)
35.1 Introduction
NOTE
For the chip-specific implementation details of this module's
instances see the chip configuration information.
This section describes the USB. The OTG implementation in this module provides
limited host functionality and device solutions for implementing a USB 2.0 full-speed/
low-speed compliant peripheral. The OTG implementation supports the On-The-Go
(OTG) addendum to the USB 2.0 Specification. Only one protocol can be active at any
time. A negotiation protocol must be used to switch to a USB host functionality from a
USB device. This is known as the Master Negotiation Protocol (MNP).

35.1.1 USB
The USB is a cable bus that supports data exchange between a host computer and a wide
range of simultaneously accessible peripherals. The attached peripherals share USB
bandwidth through a host-scheduled, token-based protocol. The bus allows peripherals to
be attached, configured, used, and detached while the host and other peripherals are in
operation.
USB software provides a uniform view of the system for all application software, hiding
implementation details making application software more portable. It manages the
dynamic attach and detach of peripherals.
There is only one host in any USB system. The USB interface to the host computer
system is referred to as the Host Controller.
There may be multiple USB devices in any system such as joysticks, speakers, printers,
etc. USB devices present a standard USB interface in terms of comprehension, response,
and standard capability.
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Introduction

The host initiates transactions to specific peripherals, whereas the device responds to
control transactions. The device sends and receives data to and from the host using a
standard USB data format. USB 2.0 full-speed /low-speed peripherals operate at 12Mbit/s
or 1.5 Mbit/s.
For additional information, see the USB 2.0 specification.
Host PC

External Hub
External Hub
Root
Hub

Host
Software

USB Cable

USB Cable

USB Cables

USB Cable

USB Peripherals

Figure 35-1. Example USB 2.0 system configuration

35.1.2 USB On-The-Go
USB is a popular standard for connecting peripherals and portable consumer electronic
devices such as digital cameras and hand-held computers to host PCs. The On-The-Go
(OTG) Supplement to the USB Specification extends USB to peer-to-peer application.
Using USB OTG technology consumer electronics, peripherals, and portable devices can
connect to each other to exchange data. For example, a digital camera can connect
directly to a printer, or a keyboard can connect to a Personal Digital Assistant to
exchange data.
With the USB On-The-Go product, you can develop a fully USB-compliant peripheral
device that can also assume the role of a USB host. Software determines the role of the
device based on hardware signals, and then initializes the device in the appropriate mode
of operation (host or peripheral) based on how it is connected. After connecting the
devices can negotiate using the OTG protocols to assume the role of host or peripheral
based on the task to be accomplished.
For additional information, see the On-The-Go Supplement to the USB 2.0 Specification.
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Chapter 35 Universal Serial Bus OTG Controller (USBOTG)
Print Photos
Keyboard Input

Swap Songs
Hot Sync

Figure 35-2. Example USB 2.0 On-The-Go configurations

35.1.3 USB-FS Features
• USB 1.1 and 2.0 compliant full-speed device controller
• 16 bidirectional end points
• DMA or FIFO data stream interfaces
• Low-power consumption
• On-The-Go protocol logic

35.2 Functional description
The USB-FS 2.0 full-speed/low-speed module communicates with the processor core
through status registers, control registers, and data structures in memory.

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Programmers interface

35.2.1 Data Structures
The function of the device operation is to transfer a request in the memory image to and
from the Universal Serial Bus. To efficiently manage USB endpoint communications the
USB-FS implements a Buffer Descriptor Table (BDT) in system memory. See Figure
35-3.

35.3 Programmers interface
This section discusses the major components of the programming model for the USB
module.

35.3.1 Buffer Descriptor Table
To efficiently manage USB endpoint communications the USB-FS implements a Buffer
Descriptor Table (BDT) in system memory. The BDT resides on a 512-byte boundary in
system memory and is pointed to by the BDT Page Registers. Every endpoint direction
requires two 8-byte Buffer Descriptor (BD) entries. Therefore, a system with 16 fully
bidirectional endpoints would require 512 bytes of system memory to implement the
BDT. The two BD entries allows for an EVEN BD and ODD BD entry for each endpoint
direction. This allows the microprocessor to process one BD while the USB-FS is
processing the other BD. Double buffering BDs in this way allows the USB-FS to
transfer data easily at the maximum throughput provided by USB.
The software API intelligently manages buffers for the USB-FS by updating the BDT
when needed. This allows the USB-FS to efficiently manage data transmission and
reception, while the microprocessor performs communication overhead processing and
other function dependent applications. Because the buffers are shared between the
microprocessor and the USB-FS, a simple semaphore mechanism is used to distinguish
who is allowed to update the BDT and buffers in system memory. A semaphore, the
OWN bit, is cleared to 0 when the BD entry is owned by the microprocessor. The
microprocessor is allowed read and write access to the BD entry and the buffer in system
memory when the OWN bit is 0. When the OWN bit is set to 1, the BD entry and the
buffer in system memory are owned by the USB-FS. The USB-FS now has full read and
write access and the microprocessor must not modify the BD or its corresponding data
buffer. The BD also contains indirect address pointers to where the actual buffer resides
in system memory. This indirect address mechanism is shown in the following diagram.

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System Memory

BDT_PAGE Registers

END_POINT

TX

ODD

000

BDT Page

Current
Endpoint
BDT
•••

Start of Buffer
•••

Buffer in Memory

Figure 35-3. Buffer descriptor table

35.3.2 RX vs. TX as a USB target device or USB host
The USB-FS core uses software control to switch between two modes of operation:
• USB target device
• USB hosts
In either mode, USB host or USB target device, the same data paths and buffer
descriptors are used for the transmission and reception of data. For this reason, a USB-FS
core centric nomenclature is used to describe the direction of the data transfer between
the USB-FS core and the USB:
• RX (or receive) describes transfers that move data from the USB to memory.
• TX (or transmit) describes transfers that move data from memory to the USB.
The following table shows how the data direction corresponds to the USB token type in
host and target device applications.
Table 35-1. Data direction for USB host or USB target
Device
Host

RX

TX

OUT or SETUP

IN

IN

OUT or SETUP

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35.3.3 Addressing BDT entries
An understanding of the addressing mechanism of the Buffer Descriptor Table is useful
when accessing endpoint data via the USB-FS or microprocessor. Some points of interest
are:
•
•
•
•
•
•
•

The BDT occupies up to 512 bytes of system memory.
16 bidirectional endpoints can be supported with a full BDT of 512 bytes.
16 bytes are needed for each USB endpoint direction.
Applications with less than 16 endpoints require less RAM to implement the BDT.
The BDT Page Registers (BDT_PAGE) point to the starting location of the BDT.
The BDT must be located on a 512-byte boundary in system memory.
All enabled TX and RX endpoint BD entries are indexed into the BDT to allow easy
access via the USB-FS or MCU core.

When a USB token on an enabled endpoint is received, the USB-FS uses its integrated
DMA controller to interrogate the BDT. The USB-FS reads the corresponding endpoint
BD entry to determine whether it owns the BD and corresponding buffer in system
memory.
To compute the entry point in to the BDT, the BDT_PAGE registers is concatenated with
the current endpoint and the TX and ODD fields to form a 32-bit address. This address
mechanism is shown below:
Table 35-2. BDT address calculation fields
Field

Description

BDT_PAGE

BDT_PAGE registers in the Control Register Block

END_POINT

END POINT field from the USB TOKEN

TX

1 for transmit transfers and 0 for receive transfers

ODD

Maintained within the USB-FS SIE. It corresponds to the buffer currently in use. The buffers are
used in a ping-pong fashion.

35.3.4 Buffer Descriptors (BDs)
A buffer descriptor provides endpoint buffer control information for the USB-FS and
processor. The Buffer Descriptors have different meaning based on whether it is the
USB-FS or processor reading the BD in memory.
The USB-FS Controller uses the data stored in the BDs to determine:

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• Who owns the buffer in system memory
• Data0 or Data1 PID
• Whether to release ownership upon packet completion
• No address increment (FIFO mode)
• Whether data toggle synchronization is enabled
• How much data is to be transmitted or received
• Where the buffer resides in system memory
While the processor uses the data stored in the BDs to determine:
• Who owns the buffer in system memory
• Data0 or Data1 PID
• The received TOKEN PID
• How much data was transmitted or received
• Where the buffer resides in system memory
The format for the BD is shown in the following figure.
Table 35-3. Buffer descriptor format
31:26
RSVD

25:16
BC
(10 bits)

15:8

7

6

RSVD

OWN

DATA0/1

5

4

3

2

KEEP/

NINC/

DTS/

BDT_STALL/

TOK_PID[3]

TOK_PID[2]

TOK_PID[1]

TOK_PID[0]

1

0

0

0

Buffer Address (32-Bits)

Table 35-4. Buffer descriptor fields
Field
31–26

Description
Reserved

RSVD
25–16
BC
15–8

Byte Count
Represents the 10-bit byte count. The USB-FS SIE changes this field upon the completion of a RX
transfer with the byte count of the data received.
Reserved

RSVD
Table continues on the next page...

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Table 35-4. Buffer descriptor fields (continued)
Field
7
OWN

Description
Determines whether the processor or the USB-FS currently owns the buffer. Except when KEEP=1,
the SIE hands ownership back to the processor after completing the token by clearing this bit.
This must always be the last byte of the BD that the processor updates when it initializes a BD.
0 The processor has exclusive access to the BD. The USB-FS ignores all other fields in the BD.
1 USB-FS has exclusive access to the BD. After the BD has been assigned to the USB-FS, the
processor should not change it in any way.

6
DATA0/1
5
KEEP/
TOK_PID[3]

Defines whether a DATA0 field (DATA0/1=0) or a DATA1 (DATA0/1=1) field was transmitted or
received. It is unchanged by the USB-FS.
Typically, this bit is 1 with ISO endpoints feeding a FIFO. The microprocessor is not informed that a
token has been processed, the data is simply transferred to or from the FIFO. When KEEP is set,
normally the NINC bit is also set to prevent address increment.
0 Bit 3 of the current token PID is written back to the BD by the USB-FS. Allows the USB-FS to
release the BD when a token has been processed.
1 This bit is unchanged by the USB-FS. If the OWN bit also is set, the BD remains owned by the
USB-FS forever.

4
NINC/
TOK_PID[2]

No Increment (NINC)
Disables the DMA engine address increment. This forces the DMA engine to read or write from the
same address. This is useful for endpoints when data needs to be read from or written to a single
location such as a FIFO. Typically this bit is set with the KEEP bit for ISO endpoints that are
interfacing to a FIFO.
0 The USB-FS writes bit 2 of the current token PID to the BD.
1 This bit is unchanged by the USB-FS.

3
DTS/
TOK_PID[1]

Setting this bit enables the USB-FS to perform Data Toggle Synchronization.
• If KEEP=0, bit 1 of the current token PID is written back to the BD.
• If KEEP=1, this bit is unchanged by the USB-FS.
0 Data Toggle Synchronization is disabled.
1 Enables the USB-FS to perform Data Toggle Synchronization.

2
BDT_STALL
TOK_PID[0]

Setting this bit causes the USB-FS to issue a STALL handshake if a token is received by the SIE
that would use the BDT in this location. The BDT is not consumed by the SIE (the owns bit remains
set and the rest of the BDT is unchanged) when a BDT-STALL bit is set.
• If KEEP=0, bit 0 of the current token PID is written back to the BD.
• If KEEP=1, this bit is unchanged by the USB-FS.
0 No stall issued.
1 The BDT is not consumed by the SIE (the OWN bit remains set and the rest of the BDT is
unchanged).
Table continues on the next page...

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Table 35-4. Buffer descriptor fields (continued)
Field
TOK_PID[n]

Description
Bits [5:2] can also represent the current token PID. The current token PID is written back in to the
BD by the USB-FS when a transfer completes. The values written back are the token PID values
from the USB specification:
• 0x1h for an OUT token.
• 0x9h for an IN token.
• 0xDh for a SETUP token.
In host mode, this field is used to report the last returned PID or a transfer status indication. The
possible values returned are:
•
•
•
•
•
•
•

1–0

0x3h DATA0
0xBh DATA1
0x2h ACK
0xEh STALL
0xAh NAK
0x0h Bus Timeout
0xFh Data Error

Reserved, should read as zeroes.

Reserved
ADDR[31:0]

Address
Represents the 32-bit buffer address in system memory. These bits are unchanged by the USBFS.

35.3.5 USB transaction
When the USB-FS transmits or receives data, it computes the BDT address using the
address generation shown in "Addressing Buffer Descriptor Entries" table.
If OWN =1, the following process occurs:
1. The USB-FS reads the BDT.
2. The SIE transfers the data via the DMA to or from the buffer pointed to by the
ADDR field of the BD.
3. When the TOKEN is complete, the USB-FS updates the BDT and, if KEEP=0,
changes the OWN bit to 0.
4. The STAT register is updated and the TOK_DNE interrupt is set.
5. When the processor processes the TOK_DNE interrupt, it reads from the status
register all the information needed to process the endpoint.
6. At this point, the processor allocates a new BD so that additional USB data can be
transmitted or received for that endpoint, and then processes the last BD.
The following figure shows a timeline of how a typical USB token is processed after the
BDT is read and OWN=1.
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USB RST

SOF

USB_RST
Interrupt Generated

SOF Interrupt Generated

SETUP TOKEN

DATA

ACK
TOK_DNE
Interrupt Generated

DATA

IN TOKEN

ACK
TOK_DNE
Interrupt Generated

OUT TOKEN

DATA

USB Host

ACK
TOK_DNE
Interrupt Generated

Function

Figure 35-4. USB token transaction

The USB has two sources for the DMA overrun error:
Memory Latency
The memory latency may be too high and cause the receive FIFO to overflow. This is
predominantly a hardware performance issue, usually caused by transient memory access
issues.
Oversized Packets
The packet received may be larger than the negotiated MaxPacket size. Typically, this is
caused by a software bug. For DMA overrun errors due to oversized data packets, the
USB specification is ambiguous. It assumes correct software drivers on both sides.
NAKing the packet can result in retransmission of the already oversized packet data.
Therefore, in response to oversized packets, the USB core continues ACKing the packet
for non-isochronous transfers.
Table 35-5. USB responses to DMA overrun errors
Errors due to Memory Latency
Non-Acknowledgment (NAK) or Bus Timeout (BTO) — See
bit 4 in "Error Interrupt Status Register (ERRSTAT)" as
appropriate for the class of transaction.
—

Errors due to Oversized Packets
Continues acknowledging (ACKing) the packet for nonisochronous transfers.
The data written to memory is clipped to the MaxPacket size
so as not to corrupt system memory.

The DMAERR bit is set in the ERRSTAT register for host and Asserts ERRSTAT[DMAERR] ,which can trigger an interrupt
device modes of operation. Depending on the values of the
and TOKDNE interrupt fires. Note: The TOK_PID field of the
INTENB and ERRENB register, the core may assert an
BDT is not 1111 because the DMAERR is not due to latency.
interrupt to notify the processor of the DMA error.
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Table 35-5. USB responses to DMA overrun errors (continued)
Errors due to Memory Latency

Errors due to Oversized Packets

• For host mode, the TOKDNE interrupt is generated and The packet length field written back to the BDT is the
the TOK_PID field of the BDT is 1111 to indicate the
MaxPacket value that represents the length of the clipped
DMA latency error. Host mode software can decide to
data actually written to memory.
retry or move to next scheduled item.
• In device mode, the BDT is not written back nor is the
TOKDNE interrupt triggered because it is assumed that
a second attempt is queued and will succeed in the
future.
From here, the software can decide an appropriate course of action for future transactions such as stalling the endpoint,
canceling the transfer, disabling the endpoint, etc.

35.4 Memory map/Register definitions
This section provides the memory map and detailed descriptions of all USB interface
registers.
USB memory map
Absolute
address
(hex)

Register name

Width
Access
(in bits)

Reset value

Section/
page

4007_2000

Peripheral ID register (USB0_PERID)

8

R

04h

35.4.1/623

4007_2004

Peripheral ID Complement register (USB0_IDCOMP)

8

R

FBh

35.4.2/624

4007_2008

Peripheral Revision register (USB0_REV)

8

R

33h

35.4.3/624

4007_200C

Peripheral Additional Info register (USB0_ADDINFO)

8

R

01h

35.4.4/625

4007_2010

OTG Interrupt Status register (USB0_OTGISTAT)

8

R/W

00h

35.4.5/625

4007_2014

OTG Interrupt Control Register (USB0_OTGICR)

8

R/W

00h

35.4.6/626

4007_2018

OTG Status register (USB0_OTGSTAT)

8

R/W

00h

35.4.7/627

4007_201C

OTG Control register (USB0_OTGCTL)

8

R/W

00h

35.4.8/628

4007_2080

Interrupt Status register (USB0_ISTAT)

8

R/W

00h

35.4.9/629

4007_2084

Interrupt Enable register (USB0_INTEN)

8

R/W

00h

35.4.10/
630

4007_2088

Error Interrupt Status register (USB0_ERRSTAT)

8

R/W

00h

35.4.11/
631

4007_208C

Error Interrupt Enable register (USB0_ERREN)

8

R/W

00h

35.4.12/
632

4007_2090

Status register (USB0_STAT)

8

R

00h

35.4.13/
633

4007_2094

Control register (USB0_CTL)

8

R/W

00h

35.4.14/
634

4007_2098

Address register (USB0_ADDR)

8

R/W

00h

35.4.15/
635

Table continues on the next page...

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USB memory map (continued)
Absolute
address
(hex)

Register name

Width
Access
(in bits)

Reset value

Section/
page

4007_209C

BDT Page Register 1 (USB0_BDTPAGE1)

8

R/W

00h

35.4.16/
636

4007_20A0

Frame Number Register Low (USB0_FRMNUML)

8

R/W

00h

35.4.17/
636

4007_20A4

Frame Number Register High (USB0_FRMNUMH)

8

R/W

00h

35.4.18/
637

4007_20A8

Token register (USB0_TOKEN)

8

R/W

00h

35.4.19/
637

4007_20AC SOF Threshold Register (USB0_SOFTHLD)

8

R/W

00h

35.4.20/
638

4007_20B0

BDT Page Register 2 (USB0_BDTPAGE2)

8

R/W

00h

35.4.21/
639

4007_20B4

BDT Page Register 3 (USB0_BDTPAGE3)

8

R/W

00h

35.4.22/
639

4007_20C0

Endpoint Control register (USB0_ENDPT0)

8

R/W

00h

35.4.23/
639

4007_20C4

Endpoint Control register (USB0_ENDPT1)

8

R/W

00h

35.4.23/
639

4007_20C8

Endpoint Control register (USB0_ENDPT2)

8

R/W

00h

35.4.23/
639

4007_20CC Endpoint Control register (USB0_ENDPT3)

8

R/W

00h

35.4.23/
639

4007_20D0

Endpoint Control register (USB0_ENDPT4)

8

R/W

00h

35.4.23/
639

4007_20D4

Endpoint Control register (USB0_ENDPT5)

8

R/W

00h

35.4.23/
639

4007_20D8

Endpoint Control register (USB0_ENDPT6)

8

R/W

00h

35.4.23/
639

4007_20DC Endpoint Control register (USB0_ENDPT7)

8

R/W

00h

35.4.23/
639

4007_20E0

Endpoint Control register (USB0_ENDPT8)

8

R/W

00h

35.4.23/
639

4007_20E4

Endpoint Control register (USB0_ENDPT9)

8

R/W

00h

35.4.23/
639

4007_20E8

Endpoint Control register (USB0_ENDPT10)

8

R/W

00h

35.4.23/
639

4007_20EC Endpoint Control register (USB0_ENDPT11)

8

R/W

00h

35.4.23/
639

4007_20F0

Endpoint Control register (USB0_ENDPT12)

8

R/W

00h

35.4.23/
639

4007_20F4

Endpoint Control register (USB0_ENDPT13)

8

R/W

00h

35.4.23/
639

4007_20F8

Endpoint Control register (USB0_ENDPT14)

8

R/W

00h

35.4.23/
639

Table continues on the next page...

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USB memory map (continued)
Absolute
address
(hex)

Width
Access
(in bits)

Register name

Reset value

Section/
page

4007_20FC Endpoint Control register (USB0_ENDPT15)

8

R/W

00h

35.4.23/
639

4007_2100

USB Control register (USB0_USBCTRL)

8

R/W

C0h

35.4.24/
640

4007_2104

USB OTG Observe register (USB0_OBSERVE)

8

R

50h

35.4.25/
641

4007_2108

USB OTG Control register (USB0_CONTROL)

8

R/W

00h

35.4.26/
642

4007_210C

USB Transceiver Control Register 0 (USB0_USBTRC0)

8

R/W

00h

35.4.27/
642

4007_2114

Frame Adjust Register (USB0_USBFRMADJUST)

8

R/W

00h

35.4.28/
643

35.4.1 Peripheral ID register (USBx_PERID)
Reads back the value of 0x04. This value is defined for the USB peripheral.
Address: 4007_2000h base + 0h offset = 4007_2000h
Bit

7

Read

6

5

4

3

0

2

1

0

1

0

0

ID

Write
Reset

0

0

0

0

0

USBx_PERID field descriptions
Field
7–6
Reserved
5–0
ID

Description
This field is reserved.
This read-only field is reserved and always has the value 0.
Peripheral Identification
This field always reads 0x4h.

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35.4.2 Peripheral ID Complement register (USBx_IDCOMP)
Reads back the complement of the Peripheral ID register. For the USB peripheral, the
value is 0xFB.
Address: 4007_2000h base + 4h offset = 4007_2004h
Bit

7

Read

6

5

4

3

2

1

0

0

1

1

3

2

1

0

0

0

1

1

1

NID

Write
Reset

1

1

1

1

1

USBx_IDCOMP field descriptions
Field
7–6
Reserved
5–0
NID

Description
This field is reserved.
This read-only field is reserved and always has the value 1.
Ones complement of peripheral identification bits.

35.4.3 Peripheral Revision register (USBx_REV)
Contains the revision number of the USB module.
Address: 4007_2000h base + 8h offset = 4007_2008h
Bit

7

6

5

4

Read

REV

Write
Reset

0

0

1

1

USBx_REV field descriptions
Field
7–0
REV

Description
Revision
Indicate the revision number of the USB Core.

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35.4.4 Peripheral Additional Info register (USBx_ADDINFO)
Reads back the value of the fixed Interrupt Request Level (IRQNUM) along with the
Host Enable bit.
Address: 4007_2000h base + Ch offset = 4007_200Ch
Bit

7

6

5

Read

4

3

2

IRQNUM

1

0

0

IEHOST

Write
Reset

0

0

0

0

0

0

0

1

USBx_ADDINFO field descriptions
Field

Description

7–3
IRQNUM

Assigned Interrupt Request Number

2–1
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

0
IEHOST

When this bit is set, the USB peripheral is operating in host mode.

35.4.5 OTG Interrupt Status register (USBx_OTGISTAT)
Records changes of the ID sense and VBUS signals. Software can read this register to
determine the event that triggers interrupt. Only bits that have changed since the last
software read are set. Writing a one to a bit clears the associated interrupt.
Address: 4007_2000h base + 10h offset = 4007_2010h
Bit

7

6

5

4

0

IDCHG

ONEMSEC

LINE_
STATE_
CHG

0

0

0

0

Read
Write
Reset

3

2

SESSVLDC
HG

B_SESS_
CHG

0

0

1

0

0
AVBUSCHG
0

0

USBx_OTGISTAT field descriptions
Field
7
IDCHG
6
ONEMSEC
5
LINE_STATE_
CHG

Description
This bit is set when a change in the ID Signal from the USB connector is sensed.
This bit is set when the 1 millisecond timer expires. This bit stays asserted until cleared by software. The
interrupt must be serviced every millisecond to avoid losing 1msec counts.
This bit is set when the USB line state changes. The interrupt associated with this bit can be used to
detect Reset, Resume, Connect, and Data Line Pulse signaling
Table continues on the next page...

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USBx_OTGISTAT field descriptions (continued)
Field
4
Reserved

Description
This field is reserved.
This read-only field is reserved and always has the value 0.

3
SESSVLDCHG

This bit is set when a change in VBUS is detected indicating a session valid or a session no longer valid.

2
B_SESS_CHG

This bit is set when a change in VBUS is detected on a B device.

1
Reserved
0
AVBUSCHG

This field is reserved.
This read-only field is reserved and always has the value 0.
This bit is set when a change in VBUS is detected on an A device.

35.4.6 OTG Interrupt Control Register (USBx_OTGICR)
Enables the corresponding interrupt status bits defined in the OTG Interrupt Status
Register.
Address: 4007_2000h base + 14h offset = 4007_2014h
Bit

Read
Write
Reset

7

6

IDEN
0

5

ONEMSEC LINESTATE
EN
EN
0

0

4

3

2

1

0

SESSVLDE
N

BSESSEN

0

0

0

0
0

0

AVBUSEN
0

USBx_OTGICR field descriptions
Field
7
IDEN

Description
ID Interrupt Enable
0
1

The ID interrupt is disabled
The ID interrupt is enabled

6
ONEMSECEN

One Millisecond Interrupt Enable

5
LINESTATEEN

Line State Change Interrupt Enable

4
Reserved
3
SESSVLDEN

2
BSESSEN

0
1

0
1

Diables the 1ms timer interrupt.
Enables the 1ms timer interrupt.

Disables the LINE_STAT_CHG interrupt.
Enables the LINE_STAT_CHG interrupt.

This field is reserved.
This read-only field is reserved and always has the value 0.
Session Valid Interrupt Enable
0
1

Disables the SESSVLDCHG interrupt.
Enables the SESSVLDCHG interrupt.

B Session END Interrupt Enable
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USBx_OTGICR field descriptions (continued)
Field

Description
0
1

Disables the B_SESS_CHG interrupt.
Enables the B_SESS_CHG interrupt.

1
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

0
AVBUSEN

A VBUS Valid Interrupt Enable
0
1

Disables the AVBUSCHG interrupt.
Enables the AVBUSCHG interrupt.

35.4.7 OTG Status register (USBx_OTGSTAT)
Displays the actual value from the external comparator outputs of the ID pin and VBUS.
Address: 4007_2000h base + 18h offset = 4007_2018h
Bit

7

Read
Write
Reset

5

4

ID

ONEMSECEN

LINESTATESTABLE

0

0

0

0

0

3

2

1

0

Bit

Read
Write
Reset

6

SESS_VLD

BSESSEND

0

0

0

0

AVBUSVLD
0

USBx_OTGSTAT field descriptions
Field
7
ID

6
ONEMSECEN

Description
Indicates the current state of the ID pin on the USB connector
0
1

Indicates a Type A cable is plugged into the USB connector.
Indicates no cable is attached or a Type B cable is plugged into the USB connector.

This bit is reserved for the 1ms count, but it is not useful to software.

5
Indicates that the internal signals that control the LINE_STATE_CHG field of OTGISTAT are stable for
LINESTATESTABLE at least 1 millisecond. First read LINE_STATE_CHG field and then read this field. If this field reads as
1, then the value of LINE_STATE_CHG can be considered stable.
0
1
4
Reserved
3
SESS_VLD

The LINE_STAT_CHG bit is not yet stable.
The LINE_STAT_CHG bit has been debounced and is stable.

This field is reserved.
This read-only field is reserved and always has the value 0.
Session Valid
0
1

The VBUS voltage is below the B session valid threshold
The VBUS voltage is above the B session valid threshold.
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USBx_OTGSTAT field descriptions (continued)
Field

Description

2
BSESSEND

B Session End
0
1

1
Reserved

The VBUS voltage is above the B session end threshold.
The VBUS voltage is below the B session end threshold.

This field is reserved.
This read-only field is reserved and always has the value 0.

0
AVBUSVLD

A VBUS Valid
0
1

The VBUS voltage is below the A VBUS Valid threshold.
The VBUS voltage is above the A VBUS Valid threshold.

35.4.8 OTG Control register (USBx_OTGCTL)
Controls the operation of VBUS and Data Line termination resistors.
Address: 4007_2000h base + 1Ch offset = 4007_201Ch
Bit

Read
Write
Reset

7

6

5

DPHIGH

0

DPLOW

0

0

0

4

3

2

DMLOW

0

OTGEN

0

0

0

1

0

0
0

0

USBx_OTGCTL field descriptions
Field

Description

7
DPHIGH

D+ Data Line pullup resistor enable

6
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

5
DPLOW

0
1

D+ pullup resistor is not enabled
D+ pullup resistor is enabled

D+ Data Line pull-down resistor enable
This bit should always be enabled together with bit 4 (DMLOW)
0
1

D+ pulldown resistor is not enabled.
D+ pulldown resistor is enabled.

4
DMLOW

D– Data Line pull-down resistor enable

3
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

2
OTGEN

0
1

D- pulldown resistor is not enabled.
D- pulldown resistor is enabled.

On-The-Go pullup/pulldown resistor enable
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USBx_OTGCTL field descriptions (continued)
Field

Description
0
1

1–0
Reserved

If USB_EN is 1 and HOST_MODE is 0 in the Control Register (CTL), then the D+ Data Line pull-up
resistors are enabled. If HOST_MODE is 1 the D+ and D– Data Line pull-down resistors are engaged.
The pull-up and pull-down controls in this register are used.

This field is reserved.
This read-only field is reserved and always has the value 0.

35.4.9 Interrupt Status register (USBx_ISTAT)
Contains fields for each of the interrupt sources within the USB Module. Each of these
fields are qualified with their respective interrupt enable bits. All fields of this register are
logically OR'd together along with the OTG Interrupt Status Register (OTGSTAT) to
form a single interrupt source for the processor's interrupt controller. After an interrupt
bit has been set it may only be cleared by writing a one to the respective interrupt bit.
This register contains the value of 0x00 after a reset.
Address: 4007_2000h base + 80h offset = 4007_2080h
Bit

7

6

5

4

3

2

1

0

Read

STALL

ATTACH

RESUME

SLEEP

TOKDNE

SOFTOK

ERROR

USBRST

Write

w1c

w1c

w1c

w1c

w1c

w1c

w1c

w1c

Reset

0

0

0

0

0

0

0

0

USBx_ISTAT field descriptions
Field
7
STALL

Description
Stall Interrupt
In Target mode this bit is asserted when a STALL handshake is sent by the SIE.
In Host mode this bit is set when the USB Module detects a STALL acknowledge during the handshake
phase of a USB transaction.This interrupt can be used to determine whether the last USB transaction was
completed successfully or stalled.

6
ATTACH

Attach Interrupt

5
RESUME

This bit is set depending upon the DP/DM signals, and can be used to signal remote wake-up signaling on
the USB bus. When not in suspend mode this interrupt must be disabled.

This bit is set when the USB Module detects an attach of a USB device. This signal is only valid if
HOSTMODEEN is true. This interrupt signifies that a peripheral is now present and must be configured.

4
SLEEP

This bit is set when the USB Module detects a constant idle on the USB bus for 3 ms. The sleep timer is
reset by activity on the USB bus.

3
TOKDNE

This bit is set when the current token being processed has completed. The processor must immediately
read the STATUS (STAT) register to determine the EndPoint and BD used for this token. Clearing this bit
(by writing a one) causes STAT to be cleared or the STAT holding register to be loaded into the STAT
register.

2
SOFTOK

This bit is set when the USB Module receives a Start Of Frame (SOF) token.
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USBx_ISTAT field descriptions (continued)
Field

Description
In Host mode this field is set when the SOF threshold is reached, so that software can prepare for the next
SOF.

1
ERROR

This bit is set when any of the error conditions within Error Interrupt Status (ERRSTAT) register occur. The
processor must then read the ERRSTAT register to determine the source of the error.

0
USBRST

This bit is set when the USB Module has decoded a valid USB reset. This informs the processor that it
should write 0x00 into the address register and enable endpoint 0. USBRST is set after a USB reset has
been detected for 2.5 microseconds. It is not asserted again until the USB reset condition has been
removed and then reasserted.

35.4.10 Interrupt Enable register (USBx_INTEN)
Contains enable fields for each of the interrupt sources within the USB Module. Setting
any of these bits enables the respective interrupt source in the ISTAT register. This
register contains the value of 0x00 after a reset.
Address: 4007_2000h base + 84h offset = 4007_2084h
Bit

Read
Write
Reset

7

6

STALLEN
0

5

ATTACHEN RESUMEEN
0

0

4

3

SLEEPEN
0

2

1

0

TOKDNEEN SOFTOKEN ERROREN USBRSTEN
0

0

0

0

USBx_INTEN field descriptions
Field
7
STALLEN

Description
STALL Interrupt Enable
0
1

Diasbles the STALL interrupt.
Enables the STALL interrupt.

6
ATTACHEN

ATTACH Interrupt Enable

5
RESUMEEN

RESUME Interrupt Enable

4
SLEEPEN

0
1

0
1

Disables the ATTACH interrupt.
Enables the ATTACH interrupt.

Disables the RESUME interrupt.
Enables the RESUME interrupt.

SLEEP Interrupt Enable
0
1

Disables the SLEEP interrupt.
Enables the SLEEP interrupt.

3
TOKDNEEN

TOKDNE Interrupt Enable

2
SOFTOKEN

SOFTOK Interrupt Enable

0
1

Disables the TOKDNE interrupt.
Enables the TOKDNE interrupt.

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USBx_INTEN field descriptions (continued)
Field

Description
0
1

Disbles the SOFTOK interrupt.
Enables the SOFTOK interrupt.

1
ERROREN

ERROR Interrupt Enable

0
USBRSTEN

USBRST Interrupt Enable

0
1

0
1

Disables the ERROR interrupt.
Enables the ERROR interrupt.

Disables the USBRST interrupt.
Enables the USBRST interrupt.

35.4.11 Error Interrupt Status register (USBx_ERRSTAT)
Contains enable bits for each of the error sources within the USB Module. Each of these
bits are qualified with their respective error enable bits. All bits of this register are
logically OR'd together and the result placed in the ERROR bit of the ISTAT register.
After an interrupt bit has been set it may only be cleared by writing a one to the
respective interrupt bit. Each bit is set as soon as the error conditions is detected.
Therefore, the interrupt does not typically correspond with the end of a token being
processed. This register contains the value of 0x00 after a reset.
Address: 4007_2000h base + 88h offset = 4007_2088h
7

6

5

4

3

2

1

0

Read

Bit

BTSERR

0

DMAERR

BTOERR

DFN8

CRC16

CRC5EOF

PIDERR

Write

w1c

w1c

w1c

w1c

w1c

w1c

w1c

Reset

0

0

0

0

0

0

0

0

USBx_ERRSTAT field descriptions
Field

Description

7
BTSERR

This bit is set when a bit stuff error is detected. If set, the corresponding packet is rejected due to the error.

6
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

5
DMAERR

This bit is set if the USB Module has requested a DMA access to read a new BDT but has not been given
the bus before it needs to receive or transmit data. If processing a TX transfer this would cause a transmit
data underflow condition. If processing a RX transfer this would cause a receive data overflow condition.
This interrupt is useful when developing device arbitration hardware for the microprocessor and the USB
module to minimize bus request and bus grant latency. This bit is also set if a data packet to or from the
host is larger than the buffer size allocated in the BDT. In this case the data packet is truncated as it is put
in buffer memory.

4
BTOERR

This bit is set when a bus turnaround timeout error occurs. The USB module contains a bus turnaround
timer that keeps track of the amount of time elapsed between the token and data phases of a SETUP or
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USBx_ERRSTAT field descriptions (continued)
Field

Description
OUT TOKEN or the data and handshake phases of a IN TOKEN. If more than 16 bit times are counted
from the previous EOP before a transition from IDLE, a bus turnaround timeout error occurs.

3
DFN8
2
CRC16
1
CRC5EOF

This bit is set if the data field received was not 8 bits in length. USB Specification 1.0 requires that data
fields be an integral number of bytes. If the data field was not an integral number of bytes, this bit is set.
This bit is set when a data packet is rejected due to a CRC16 error.
This error interrupt has two functions. When the USB Module is operating in peripheral mode
(HOSTMODEEN=0), this interrupt detects CRC5 errors in the token packets generated by the host. If set
the token packet was rejected due to a CRC5 error.
When the USB Module is operating in host mode (HOSTMODEEN=1), this interrupt detects End Of Frame
(EOF) error conditions. This occurs when the USB Module is transmitting or receiving data and the SOF
counter reaches zero. This interrupt is useful when developing USB packet scheduling software to ensure
that no USB transactions cross the start of the next frame.

0
PIDERR

This bit is set when the PID check field fails.

35.4.12 Error Interrupt Enable register (USBx_ERREN)
Contains enable bits for each of the error interrupt sources within the USB module.
Setting any of these bits enables the respective interrupt source in ERRSTAT. Each bit is
set as soon as the error conditions is detected. Therefore, the interrupt does not typically
correspond with the end of a token being processed. This register contains the value of
0x00 after a reset.
Address: 4007_2000h base + 8Ch offset = 4007_208Ch
Bit

7

6

Read
BTSERREN
Write
Reset
0

0

5

4

3

DMAERREN BTOERREN

0

0

0

2

1

DFN8EN

CRC16EN

0

0

0

CRC5EOFE
PIDERREN
N
0

0

USBx_ERREN field descriptions
Field
7
BTSERREN

6
Reserved
5
DMAERREN

Description
BTSERR Interrupt Enable
0
1

Disables the BTSERR interrupt.
Enables the BTSERR interrupt.

This field is reserved.
This read-only field is reserved and always has the value 0.
DMAERR Interrupt Enable
0
1

Disables the DMAERR interrupt.
Enables the DMAERR interrupt.
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USBx_ERREN field descriptions (continued)
Field
4
BTOERREN

3
DFN8EN

2
CRC16EN

1
CRC5EOFEN

0
PIDERREN

Description
BTOERR Interrupt Enable
0
1

Disables the BTOERR interrupt.
Enables the BTOERR interrupt.

DFN8 Interrupt Enable
0
1

Disables the DFN8 interrupt.
Enables the DFN8 interrupt.

CRC16 Interrupt Enable
0
1

Disables the CRC16 interrupt.
Enables the CRC16 interrupt.

CRC5/EOF Interrupt Enable
0
1

Disables the CRC5/EOF interrupt.
Enables the CRC5/EOF interrupt.

PIDERR Interrupt Enable
0
1

Disables the PIDERR interrupt.
Enters the PIDERR interrupt.

35.4.13 Status register (USBx_STAT)
Reports the transaction status within the USB module. When the processor's interrupt
controller has received a TOKDNE, interrupt the Status Register must be read to
determine the status of the previous endpoint communication. The data in the status
register is valid when TOKDNE interrupt is asserted. The Status register is actually a
read window into a status FIFO maintained by the USB module. When the USB module
uses a BD, it updates the Status register. If another USB transaction is performed before
the TOKDNE interrupt is serviced, the USB module stores the status of the next
transaction in the STAT FIFO. Thus STAT is actually a four byte FIFO that allows the
processor core to process one transaction while the SIE is processing the next transaction.
Clearing the TOKDNE bit in the ISTAT register causes the SIE to update STAT with the
contents of the next STAT value. If the data in the STAT holding register is valid, the
SIE immediately reasserts to TOKDNE interrupt.
Address: 4007_2000h base + 90h offset = 4007_2090h
Bit

7

6

Read

5

4

ENDP

3

2

TX

ODD

0

0

1

0

0

Write
Reset

0

0

0

0

0

0

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USBx_STAT field descriptions
Field

Description

7–4
ENDP

This four-bit field encodes the endpoint address that received or transmitted the previous token. This
allows the processor core to determine the BDT entry that was updated by the last USB transaction.

3
TX

Transmit Indicator
0
1

2
ODD

The most recent transaction was a receive operation.
The most recent transaction was a transmit operation.

This bit is set if the last buffer descriptor updated was in the odd bank of the BDT.

1–0
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

35.4.14 Control register (USBx_CTL)
Provides various control and configuration information for the USB module.
Address: 4007_2000h base + 94h offset = 4007_2094h
7

6

5

4

Read
Write

Bit

JSTATE

SE0

TXSUSPENDTOKENB
USY

RESET

Reset

0

0

0

0

Bit

Read
Write
Reset

3

2

1

0

HOSTMODEEN

RESUME

ODDRST

USBENSOFEN

0

0

0

0

USBx_CTL field descriptions
Field
7
JSTATE
6
SE0

Description
Live USB differential receiver JSTATE signal
The polarity of this signal is affected by the current state of LSEN .
Live USB Single Ended Zero signal

5
In Host mode, TOKEN_BUSY is set when the USB module is busy executing a USB token.
TXSUSPENDTOKENBUSY Software must not write more token commands to the Token Register when TOKEN_BUSY is
set.. Software should check this field before writing any tokens to the Token Register to ensure
that token commands are not lost.
In Target mode, TXD_SUSPEND is set when the SIE has disabled packet transmission and
reception. Clearing this bit allows the SIE to continue token processing. This bit is set by the
SIE when a SETUP Token is received allowing software to dequeue any pending packet
transactions in the BDT before resuming token processing.
4
RESET

Setting this bit enables the USB Module to generate USB reset signaling. This allows the USB
Module to reset USB peripherals. This control signal is only valid in Host mode
(HOSTMODEEN=1). Software must set RESET to 1 for the required amount of time and then
clear it to 0 to end reset signaling. For more information on reset signaling see Section 7.1.4.3
of the USB specification version 1.0.
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USBx_CTL field descriptions (continued)
Field

Description

3
HOSTMODEEN

When set to 1, this bit enables the USB Module to operate in Host mode. In host mode, the
USB module performs USB transactions under the programmed control of the host processor.

2
RESUME

When set to 1 this bit enables the USB Module to execute resume signaling. This allows the
USB Module to perform remote wake-up. Software must set RESUME to 1 for the required
amount of time and then clear it to 0. If the HOSTMODEEN bit is set, the USB module appends
a Low Speed End of Packet to the Resume signaling when the RESUME bit is cleared. For
more information on RESUME signaling see Section 7.1.4.5 of the USB specification version
1.0.

1
ODDRST

Setting this bit to 1 resets all the BDT ODD ping/pong fields to 0, which then specifies the
EVEN BDT bank.

0
USBENSOFEN

USB Enable
Setting this bit causes the SIE to reset all of its ODD bits to the BDTs. Therefore, setting this bit
resets much of the logic in the SIE. When host mode is enabled, clearing this bit causes the
SIE to stop sending SOF tokens.
0 Disables the USB Module.
1 Enables the USB Module.

35.4.15 Address register (USBx_ADDR)
Holds the unique USB address that the USB module decodes when in Peripheral mode
(HOSTMODEEN=0). When operating in Host mode (HOSTMODEEN=1) the USB
module transmits this address with a TOKEN packet. This enables the USB module to
uniquely address an USB peripheral. In either mode, USB_EN within the control register
must be 1. The Address register is reset to 0x00 after the reset input becomes active or the
USB module decodes a USB reset signal. This action initializes the Address register to
decode address 0x00 as required by the USB specification.
Address: 4007_2000h base + 98h offset = 4007_2098h
Bit

Read
Write
Reset

7

6

5

4

LSEN

3

2

1

0

0

0

0

ADDR

0

0

0

0

0

USBx_ADDR field descriptions
Field

Description

7
LSEN

Low Speed Enable bit

6–0
ADDR

USB Address

Informs the USB module that the next token command written to the token register must be performed at
low speed. This enables the USB module to perform the necessary preamble required for low-speed data
transmissions.

Defines the USB address that the USB module decodes in peripheral mode, or transmits when in host
mode.

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35.4.16 BDT Page Register 1 (USBx_BDTPAGE1)
Provides address bits 15 through 9 of the base address where the current Buffer
Descriptor Table (BDT) resides in system memory. The 32-bit BDT Base Address is
always aligned on 512-byte boundaries, so bits 8 through 0 of the base address are always
zero.
Address: 4007_2000h base + 9Ch offset = 4007_209Ch
Bit

Read
Write
Reset

7

6

5

4

3

2

1

BDTBA
0

0

0

0

0

0
0

0

0

0

USBx_BDTPAGE1 field descriptions
Field
7–1
BDTBA
0
Reserved

Description
Provides address bits 15 through 9 of the BDT base address.
This field is reserved.
This read-only field is reserved and always has the value 0.

35.4.17 Frame Number Register Low (USBx_FRMNUML)
Contains an 11-bit value used to compute the address where the current Buffer Descriptor
Table (BDT) resides in system memory.
Address: 4007_2000h base + A0h offset = 4007_20A0h
Bit

Read
Write
Reset

7

6

5

4

3

2

1

0

0

0

0

0

FRM[7:0]
0

0

0

0

USBx_FRMNUML field descriptions
Field
7–0
FRM[7:0]

Description
This 8-bit field and the 3-bit field in the Frame Number Register High are used to compute the address
where the current Buffer Descriptor Table (BDT) resides in system memory.

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35.4.18 Frame Number Register High (USBx_FRMNUMH)
Contains an 11-bit value used to compute the address where the current Buffer Descriptor
Table (BDT) resides in system memory.
Address: 4007_2000h base + A4h offset = 4007_20A4h
Bit

Read
Write
Reset

7

6

5

4

3

2

0
0

0

0

1

0

FRM[10:8]
0

0

0

0

0

USBx_FRMNUMH field descriptions
Field

Description

7–3
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

2–0
FRM[10:8]

This 3-bit field and the 8-bit field in the Frame Number Register Low are used to compute the address
where the current Buffer Descriptor Table (BDT) resides in system memory.

35.4.19 Token register (USBx_TOKEN)
Used to initiate USB transactions when in host mode (HOSTMODEEN=1). When the
software needs to execute a USB transaction to a peripheral, it writes the TOKEN type
and endpoint to this register. After this register has been written, the USB module begins
the specified USB transaction to the address contained in the address register. The
processor core must always check that the TOKEN_BUSY bit in the control register is
not 1 before writing to the Token Register. This ensures that the token commands are not
overwritten before they can be executed. The address register and endpoint control
register 0 are also used when performing a token command and therefore must also be
written before the Token Register. The address register is used to select the USB
peripheral address transmitted by the token command. The endpoint control register
determines the handshake and retry policies used during the transfer.
Address: 4007_2000h base + A8h offset = 4007_20A8h
Bit

Read
Write
Reset

7

6

5

4

3

TOKENPID
0

0

2

1

0

TOKENENDPT
0

0

0

0

0

0

USBx_TOKEN field descriptions
Field
7–4
TOKENPID

Description
Contains the token type executed by the USB module.
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USBx_TOKEN field descriptions (continued)
Field

Description
0001
1001
1101

3–0
TOKENENDPT

OUT Token. USB Module performs an OUT (TX) transaction.
IN Token. USB Module performs an In (RX) transaction.
SETUP Token. USB Module performs a SETUP (TX) transaction

Holds the Endpoint address for the token command. The four bit value written must be a valid endpoint.

35.4.20 SOF Threshold Register (USBx_SOFTHLD)
The SOF Threshold Register is used only in Host mode (HOSTMODEEN=1). When in
Host mode, the 14-bit SOF counter counts the interval between SOF frames. The SOF
must be transmitted every 1ms so therefore the SOF counter is loaded with a value of
12000. When the SOF counter reaches zero, a Start Of Frame (SOF) token is transmitted.
The SOF threshold register is used to program the number of USB byte times before the
SOF to stop initiating token packet transactions. This register must be set to a value that
ensures that other packets are not actively being transmitted when the SOF time counts to
zero. When the SOF counter reaches the threshold value, no more tokens are transmitted
until after the SOF has been transmitted.
The value programmed into the threshold register must reserve enough time to ensure the
worst case transaction completes. In general the worst case transaction is an IN token
followed by a data packet from the target followed by the response from the host. The
actual time required is a function of the maximum packet size on the bus.
Typical values for the SOF threshold are:
•
•
•
•

64-byte packets=74;
32-byte packets=42;
16-byte packets=26;
8-byte packets=18.

Address: 4007_2000h base + ACh offset = 4007_20ACh
Bit

Read
Write
Reset

7

6

5

4

3

2

1

0

0

0

0

0

CNT
0

0

0

0

USBx_SOFTHLD field descriptions
Field
7–0
CNT

Description
Represents the SOF count threshold in byte times.

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35.4.21 BDT Page Register 2 (USBx_BDTPAGE2)
Contains an 8-bit value used to compute the address where the current Buffer Descriptor
Table (BDT) resides in system memory.
Address: 4007_2000h base + B0h offset = 4007_20B0h
Bit

Read
Write
Reset

7

6

5

4

3

2

1

0

0

0

0

0

BDTBA
0

0

0

0

USBx_BDTPAGE2 field descriptions
Field

Description

7–0
BDTBA

Provides address bits 23 through 16 of the BDT base address that defines the location of Buffer Descriptor
Table resides in system memory.

35.4.22 BDT Page Register 3 (USBx_BDTPAGE3)
Contains an 8-bit value used to compute the address where the current Buffer Descriptor
Table (BDT) resides in system memory.
Address: 4007_2000h base + B4h offset = 4007_20B4h
Bit

Read
Write
Reset

7

6

5

4

3

2

1

0

0

0

0

0

BDTBA
0

0

0

0

USBx_BDTPAGE3 field descriptions
Field

Description

7–0
BDTBA

Provides address bits 31 through 24 of the BDT base address that defines the location of Buffer Descriptor
Table resides in system memory.

35.4.23 Endpoint Control register (USBx_ENDPTn)
Contains the endpoint control bits for each of the 16 endpoints available within the USB
module for a decoded address. The format for these registers is shown in the following
figure. Endpoint 0 (ENDPT0) is associated with control pipe 0, which is required for all
USB functions. Therefore, after a USBRST interrupt occurs the processor core should set
ENDPT0 to contain 0x0D.

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In Host mode ENDPT0 is used to determine the handshake, retry and low speed
characteristics of the host transfer. For Control, Bulk and Interrupt transfers, the
EPHSHK bit should be 1. For Isochronous transfers it should be 0. Common values to
use for ENDPT0 in host mode are 0x4D for Control, Bulk, and Interrupt transfers, and
0x4C for Isochronous transfers.
Address: 4007_2000h base + C0h offset + (4d × i), where i=0d to 15d
Bit

7

Read HOSTWOH
UB
Write
Reset
0

6

5

RETRYDIS
0

0
0

4

3

2

1

0

EPCTLDIS

EPRXEN

EPTXEN

EPSTALL

EPHSHK

0

0

0

0

0

USBx_ENDPTn field descriptions
Field
7
HOSTWOHUB

6
RETRYDIS

5
Reserved
4
EPCTLDIS

Description
This is a Host mode only field and is present in the control register for endpoint 0 (ENDPT0) only. When
set this bit allows the host to communicate to a directly connected low speed device. When cleared, the
host produces the PRE_PID. It then switches to low-speed signaling when sends a token to a low speed
device as required to communicate with a low speed device through a hub.
This is a Host mode only bit and is present in the control register for endpoint 0 (ENDPT0) only. When set
this bit causes the host to not retry NAK'ed (Negative Acknowledgement) transactions. When a transaction
is NAKed, the BDT PID field is updated with the NAK PID, and the TOKEN_DNE interrupt is set. When
this bit is cleared NAKed transactions is retried in hardware. This bit must be set when the host is
attempting to poll an interrupt endpoint.
This field is reserved.
This read-only field is reserved and always has the value 0.
This bit, when set, disables control (SETUP) transfers. When cleared, control transfers are enabled. This
applies if and only if the EPRXEN and EPTXEN bits are also set.

3
EPRXEN

This bit, when set, enables the endpoint for RX transfers.

2
EPTXEN

This bit, when set, enables the endpoint for TX transfers.

1
EPSTALL

When set this bit indicates that the endpoint is called. This bit has priority over all other control bits in the
EndPoint Enable Register, but it is only valid if EPTXEN=1 or EPRXEN=1. Any access to this endpoint
causes the USB Module to return a STALL handshake. After an endpoint is stalled it requires intervention
from the Host Controller.

0
EPHSHK

When set this bit enables an endpoint to perform handshaking during a transaction to this endpoint. This
bit is generally 1 unless the endpoint is Isochronous.

35.4.24 USB Control register (USBx_USBCTRL)
Address: 4007_2000h base + 100h offset = 4007_2100h
Bit

Read
Write
Reset

7

6

SUSP

PDE

1

1

5

4

3

2

1

0

0

0

0

0
0

0

0

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USBx_USBCTRL field descriptions
Field
7
SUSP

6
PDE

5–0
Reserved

Description
Places the USB transceiver into the suspend state.
0
1

USB transceiver is not in suspend state.
USB transceiver is in suspend state.

Enables the weak pulldowns on the USB transceiver.
0
1

Weak pulldowns are disabled on D+ and D–.
Weak pulldowns are enabled on D+ and D–.

This field is reserved.
This read-only field is reserved and always has the value 0.

35.4.25 USB OTG Observe register (USBx_OBSERVE)
Provides visibility on the state of the pull-ups and pull-downs at the transceiver. Useful
when interfacing to an external OTG control module via a serial interface.
Address: 4007_2000h base + 104h offset = 4007_2104h
Bit

Read

7

6

5

4

DPPU

DPPD

0

DMPD

0

1

0

1

3

2

1

0

0

0

Write
Reset

0

0

0

0

USBx_OBSERVE field descriptions
Field

Description

7
DPPU

Provides observability of the D+ Pullup . signal output from the USB OTG module

6
DPPD

Provides observability of the D+ Pulldown . signal output from the USB OTG module

5
Reserved
4
DMPD

0
1

0
1

D+ pullup disabled.
D+ pullup enabled.

D+ pulldown disabled.
D+ pulldown enabled.

This field is reserved.
This read-only field is reserved and always has the value 0.
Provides observability of the D� Pulldown . signal output from the USB OTG module
0
1

D– pulldown disabled.
D– pulldown enabled.

3–1
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

0
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

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35.4.26 USB OTG Control register (USBx_CONTROL)
Address: 4007_2000h base + 108h offset = 4007_2108h
Bit

7

6

5

4

Read
Write
Reset

0
0

0

0

0

Bit

3

2

1

0

0

0

Read
Write
Reset

DPPULLUPNONOTG

0
0

0

USBx_CONTROL field descriptions
Field

Description

7–5
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

4
Provides control of the DP Pullup in the USB OTG module, if USB is configured in non-OTG device
DPPULLUPNONOTG mode.
0
1
3–0
Reserved

DP Pullup in non-OTG device mode is not enabled.
DP Pullup in non-OTG device mode is enabled.

This field is reserved.
This read-only field is reserved and always has the value 0.

35.4.27 USB Transceiver Control Register 0 (USBx_USBTRC0)
Address: 4007_2000h base + 10Ch offset = 4007_210Ch
Bit

7

6

5

Read

4

0

USBRESMEN

Write

USBRESET

1

Reset

0

0

0

0

Bit

3

2

1

0

SYNC_DET

USB_RESUME_INT

0

0

Read

0

Write
Reset

0

0

USBx_USBTRC0 field descriptions
Field
7
USBRESET

Description
USB Reset
Generates a hard reset to the USB_OTG module. After this bit is set and the reset occurs, this bit is
automatically cleared.
Table continues on the next page...

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USBx_USBTRC0 field descriptions (continued)
Field

Description
NOTE: This bit is always read as zero. Wait two USB clock cycles after setting this bit.
0
1

6
Reserved

Normal USB module operation.
Returns the USB module to its reset state.

This field is reserved.
NOTE: Software must set this bit to 1b.

5
USBRESMEN

Asynchronous Resume Interrupt Enable
This bit, when set, allows the USB module to send an asynchronous wakeup event to the MCU upon
detection of resume signaling on the USB bus. The MCU then re-enables clocks to the USB module. It is
used for low-power suspend mode when USB module clocks are stopped or the USB transceiver is in
Suspend mode. Async wakeup only works in device mode.
0
1

4–2
Reserved
1
SYNC_DET

USB asynchronous wakeup from suspend mode disabled.
USB asynchronous wakeup from suspend mode enabled. The asynchronous resume interrupt differs
from the synchronous resume interrupt in that it asynchronously detects K-state using the unfiltered
state of the D+ and D– pins. This interupt should only be enabled when the Transceiver is suspended.

This field is reserved.
This read-only field is reserved and always has the value 0.
Synchronous USB Interrupt Detect
0
1

Synchronous interrupt has not been detected.
Synchronous interrupt has been detected.

0
USB Asynchronous Interrupt
USB_RESUME_
0 No interrupt was generated.
INT
1 Interrupt was generated because of the USB asynchronous interrupt.

35.4.28 Frame Adjust Register (USBx_USBFRMADJUST)
Address: 4007_2000h base + 114h offset = 4007_2114h
Bit

Read
Write
Reset

7

6

5

4

3

2

1

0

0

0

0

0

ADJ
0

0

0

0

USBx_USBFRMADJUST field descriptions
Field
7–0
ADJ

Description
Frame Adjustment
In Host mode, the frame adjustment is a twos complement number that adjusts the period of each USB
frame in 12-MHz clock periods. A SOF is normally generated every 12,000 12-MHz clock cycles. The
Frame Adjust Register can adjust this by -128 to +127 to compensate for inaccuracies in the USB 48-MHz
clock. Changes to the ADJ bit take effect at the next start of the next frame.

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35.5 OTG and Host mode operation
The Host mode logic allows devices such as digital cameras and palmtop computers to
function as a USB Host Controller. The OTG logic adds an interface to allow the OTG
Host Negotiation and Session Request Protocols (HNP and SRP) to be implemented in
software. Host Mode allows a peripheral such as a digital camera to be connected directly
to a USB compliant printer. Digital photos can then be easily printed without having to
upload them to a PC. In the palmtop computer application, a USB compliant keyboard/
mouse can be connected to the palmtop computer with the obvious advantages of easier
interaction.
Host mode is intended for use in handheld-portable devices to allow easy connection to
simple HID class devices such as printers and keyboards. It is not intended to perform the
functions of a full OHCI or UHCI compatible host controller found on PC motherboards.
The USB-FS is not supported by Windows 98 as a USB host controller. Host mode
allows bulk, isochronous, interrupt and control transfers. Bulk data transfers are
performed at nearly the full USB interface bandwidth. Support is provided for ISO
transfers, but the number of ISO streams that can be practically supported is affected by
the interrupt latency of the processor servicing the token during interrupts from the SIE.
Custom drivers must be written to support Host mode operation.
Setting the HOST_MODE_EN bit in the CTL register enables Host mode. The USB-FS
core can only operate as a peripheral device or in Host mode. It cannot operate in both
modes simultaneously. When HOST_MODE is enabled, only endpoint zero is used. All
other endpoints should be disabled by software.

35.6 Host Mode Operation Examples
The following sections illustrate the steps required to perform USB host functions using
the USB-FS core. While it is useful to understand the interaction of the hardware and the
software at a detailed level, an understanding of the interactions at this level is not
required to write host applications using the API software.
To enable host mode and discover a connected device:
1. Enable Host Mode (CTL[HOST_MODE_EN]=1). The pull-down resistors are
enabled, and pull-up disabled. Start of Frame (SOF) generation begins. SOF counter
loaded with 12,000. Disable SOF packet generation to eliminate noise on the USB by
writing the USB enable bit to 0 (CTL[USB_EN]=0).

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2. Enable the ATTACH interrupt (INT_ENB[ATTACH]=1).
3. Wait for ATTACH interrupt (INT_STAT[ATTACH]). Signaled by USB Target pullup resistor changing the state of DPLUS or DMINUS from 0 to 1 (SE0 to J or K
state).
4. Check the state of the JSTATE and SE0 bits in the control register. If the connecting
device is low speed (JSTATE bit is 0), set the low-speed bit in the address registers
(ADDR[LS_EN]=1) and the Host Without Hub bit in endpoint 0 register control
(ENDPT0[HOSTWOHUB]=1).
5. Enable RESET (CTL[RESET]=1) for 10 ms.
6. Enable SOF packet to keep the connected device from going to suspend
(CTL[USB_EN=1]).
7. Start enumeration by sending a sequence of device framework commands, device
frame work packets to the default control pipe of the connected device. See the
Universal Serial Bus Revision 2.0 specification, "Chapter 9 USB Device Framework"
(http://www.usb.org/developers/docs).
To complete a control transaction to a connected device:
1. Complete all the steps to discover a connected device
2. Set up the endpoint control register for bidirectional control transfers ENDPT0[4:0]
= 0x0d.
3. Place a copy of the device framework setup command in a memory buffer. See the
Universal Serial Bus Revision 2.0 specification, "Chapter 9 USB Device Framework"
(http://www.usb.org/developers/docs).
4. Initialize current even or odd TX EP0 BDT to transfer the 8 bytes of command data
for a device framework command (for example, a GET DEVICE DESCRIPTOR).
• Set the BDT command word to 0x00080080 –Byte count to 8, OWN bit to 1.
• Set the BDT buffer address field to the start address of the 8 byte command
buffer.
5. Set the USB device address of the target device in the address register (ADDR[6:0]).
After the USB bus reset, the device USB address is zero. It is set to some other value
usually 1 by the Set Address device framework command.
6. Write the token register with a SETUP to Endpoint 0 the target device default control
pipe (TOKEN=0xD0). This initiates a setup token on the bus followed by a data
packet. The device handshake is returned in the BDT PID field after the packets
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Host Mode Operation Examples

complete. When the BDT is written, a token done (ISTAT[TOKDNE]) interrupt is
asserted. This completes the setup phase of the setup transaction. Se the Universal
Serial Bus Revision 2.0 specification, "Chapter 9 USB Device Framework" (http://
www.usb.org/developers/docs).
7. To initiate the data phase of the setup transaction (that is, get the data for the GET
DEVICE DESCRIPTOR command), set up a buffer in memory for the data to be
transferred.
8. Initialize the current even or odd TX EP0 BDT to transfer the data.
• Set the BDT command word to 0x004000C0 – BC to 64 (the byte count of the
data buffer in this case), OWN bit to 1, Data toggle to Data1.
• Set the BDT buffer address field to the start address of the data buffer
9. Write the token register with a IN or OUT token to Endpoint 0 the target device
default control pipe, an IN token for a GET DEVICE DESCRIPTOR command
(TOKEN=0x90). This initiates an IN token on the bus followed by a data packet
from the device to the host. When the data packet completes, the BDT is written and
a token done (ISTAT[DNE]) interrupt is asserted. For control transfers with a single
packet data phase this completes the data phase of the setup transaction. See the
Universal Serial Bus Revision 2.0 specification, "Chapter 9 USB Device Framework"
(http://www.usb.org/developers/docs).
10. To initiate the status phase of the setup transaction, set up a buffer in memory to
receive or send the zero length status phase data packet.
11. Initialize the current even or odd TX EP0 BDT to transfer the status data.
• Set the BDT command word to 0x00000080 – BC to 0 (the byte count of the
data buffer in this case), OWN bit to 1, Data toggle to Data1.
• Set the BDT buffer address field to the start address of the data buffer
12. Write the token register with a IN or OUT token to Endpoint 0 the target device
default control pipe, an OUT token for a GET DEVICE DESCRIPTOR command
(TOKEN=0x10). This initiates an OUT token on the bus followed by a zero length
data packet from the host to the device. When the data packet completes, the BDT is
written with the handshake from the device and a Token Done (ISTAT[TOKDNE])
interrupt is asserted. This completes the data phase of the setup transaction. See the
Universal Serial Bus Revision 2.0 specification, "Chapter 9 USB Device Framework"
(http://www.usb.org/developers/docs).
To send a full speed bulk data transfer to a target device:
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1. Complete all steps to discover a connected device and to configure a connected
device. Write the ADDR register with the address of the target device. Typically,
there is only one other device on the USB bus in host mode so it is expected that the
address is 0x01 and should remain constant.
2. Write 0x1D to ENDPT0 register to enable transmit and receive transfers with
handshaking enabled.
3. Setup the even TX EP0 BDT to transfer up to 64 bytes.
4. Set the USB device address of the target device in the address register (ADDR[6:0]).
5. Write the TOKEN register with an OUT token to the desired endpoint. The write to
this register triggers the USB-FS transmit state machines to begin transmitting the
TOKEN and the data.
6. Setup the odd TX EP0 BDT to transfer up to 64 bytes.
7. Write the TOKEN register with an OUT token as in step 4. Two tokens can be
queued at a time to allow the packets to be double buffered to achieve maximum
throughput.
8. Wait for the TOKDNE interrupt. This indicates that one of the BDTs has been
released back to the processor and the transfer has completed. If the target device
asserts NAKs, the USB-FS continues to retry the transfer indefinitely without
processor intervention unless the ENDPT0[RETRYDIS] is 1. If the retry disable field
is set, the handshake (ACK, NAK, STALL, or ERROR (0xf)) is returned in the BDT
PID field. If a stall interrupt occurs, the pending packet must be dequeued and the
error condition in the target device cleared. If a Reset interrupt occurs (SE0 for more
than 2.5 μs), the target has detached.
9. After the TOK_DNE interrupt occurs, the BDTs can be examined and the next data
packet queued by returning to step 2.

35.7 On-The-Go operation
The USB-OTG core provides sensors and controls to enable On-The-Go (OTG)
operation. These sensors are used by the OTG API software to implement the Host
Negotiation Protocol (HNP) and Session Request Protocol (SRP). API calls are provided
to give access the OTG protocol control signals, and include the OTG capabilities in the
device application. The following state machines show the OTG operations involved with
HNP and SRP protocols from either end of the USB cable.

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35.7.1 OTG dual role A device operation
A device is considered the A device because of the type of cable attached. If the USB
Type A connector or the USB Type Mini A connector is plugged into the device, it is
considered the A device.
A dual role A device operates as the following flow diagram and state description table
illustrates.
A_IDLE

B_IDLE

A_WAIT_VFALL

A_WAIT_VRISE

A_PERIPHERAL

A_WAIT_BCON

A_SUSPEND

A_HOST

Figure 35-93. Dual role A device flow diagram
Table 35-96. State descriptions for the dual role A device flow
State

Action

Response

A_IDLE

If ID Interrupt.

Go to B_IDLE

The cable has been un-plugged or a Type B cable has been
attached. The device now acts as a Type B device.
If the A application wants to use the bus or if the B device is doing
Go to A_WAIT_VRISE
an SRP as indicated by an A_SESS_VLD Interrupt or Attach or Port
Turn on DRV_VBUS
Status Change Interrupt check data line for 5 –10 msec pulsing.
A_WAIT_VRISE

If ID Interrupt or if A_VBUS_VLD is false after 100 msec

Go to A_WAIT_VFALL

The cable has been changed or the A device cannot support the
current required from the B device.

Turn off DRV_VBUS

If A_VBUS_VLD interrupt

Go to A_WAIT_BCON

Table continues on the next page...

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Chapter 35 Universal Serial Bus OTG Controller (USBOTG)

Table 35-96. State descriptions for the dual role A device flow (continued)
State

Action

Response

A_WAIT_BCON

After 200 ms without Attach or ID Interrupt. (This could wait forever
if desired.)

Go to A_WAIT_FALL

A_VBUS_VLD Interrupt and B device attaches

Go to A_HOST

Turn off DRV_VBUS
Turn on Host mode

A_HOST

Enumerate Device determine OTG Support.
If A_VBUS_VLD/ Interrupt or A device is done and doesn't think he
wants to do something soon or the B device disconnects

Go to A_WAIT_VFALL
Turn off Host mode
Turn off DRV_VBUS

A_SUSPEND

If the A device is finished with session or if the A device wants to
allow the B device to take bus.

Go to A_SUSPEND

ID Interrupt or the B device disconnects

Go to A_WAIT_BCON

If ID Interrupt, or if 150 ms B disconnect timeout (This timeout value Go to A_WAIT_VFALL
could be longer) or if A_VBUS_VLD\ Interrupt
Turn off DRV_VBUS

A_PERIPHERAL

If HNP enabled, and B disconnects in 150 ms then B device is
becoming the host.

Go to A_PERIPHERAL

If A wants to start another session

Go to A_HOST

If ID Interrupt or if A_VBUS_VLD interrupt

Go to A_WAIT_VFALL

Turn off Host mode

Turn off DRV_VBUS.
If 3 –200 ms of Bus Idle

Go to A_WAIT_BCON
Turn on Host mode

A_WAIT_VFALL

If ID Interrupt or (A_SESS_VLD/ & b_conn/)

Go to A_IDLE

35.7.2 OTG dual role B device operation
A device is considered a B device if it connected to the bus with a USB Type B cable or a
USB Type Mini B cable.
A dual role B device operates as the following flow diagram and state description table
illustrates.

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On-The-Go operation

B_IDLE

A_IDLE

B_HOST

B_WAIT_ACON

B_SRP_INIT

B_PERIPHERAL

Figure 35-94. Dual role B device flow diagram
Table 35-97. State descriptions for the dual role B device flow
State

Action

Response

B_IDLE

If ID\ Interrupt.

Go to A_IDLE

A Type A cable has been plugged in and the device should now
respond as a Type A device.
If B_SESS_VLD Interrupt.

Go to B_PERIPHERAL

The A device has turned on VBUS and begins a session.

Turn on DP_HIGH

If B application wants the bus and Bus is Idle for 2 ms and the
B_SESS_END bit is set, the B device can perform an SRP.

Go to B_SRP_INIT

B_SRP_INIT

If ID\ Interrupt or SRP Done (SRP must be done in less than 100
ms.)

Go to B_IDLE

B_PERIPHERAL

If HNP enabled and the bus is suspended and B wants the bus, the
B device can become the host.

Go to B_WAIT_ACON

If A connects, an attach interrupt is received

Go to B_HOST

B_WAIT_ACON

Pulse CHRG_VBUS
Pulse DP_HIGH 5-10
ms

Turn off DP_HIGH
Turn on Host Mode

If ID\ Interrupt or B_SESS_VLD/ Interrupt

Go to B_IDLE

If the cable changes or if VBUS goes away, the host doesn't support
us.
Go to B_IDLE
B_HOST

If 3.125 ms expires or if a Resume occurs

Go to B_PERIPHERAL

If ID\ Interrupt or B_SESS_VLD\ Interrupt

Go to B_IDLE

If the cable changes or if VBUS goes away, the host doesn't support
us.
If B application is done or A disconnects

Go to B_PERIPHERAL

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Chapter 36
USB Voltage Regulator
36.1 Introduction
NOTE
For the chip-specific implementation details of this module's
instances see the chip configuration information.
The USB Voltage Regulator module is a LDO linear voltage regulator to provide 3.3V
power from an input power supply varying from 2.7 V to 5.5 V. It consists of one 3.3 V
power channel. When the input power supply is below 3.6 V, the regulator goes to passthrough mode. The following figure shows the ideal relation between the regulator output
and input power supply.
OUTPUT
(Volt)

3.3

2.1

2.7

3.6

5.5

INPUT (Volt)

Figure 36-1. Ideal Relation Between the Regulator Output and Input Power Supply

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Introduction

36.1.1 Overview
A simplified block diagram for the USB Voltage Regulator module is shown below.
STANDBY Regulator

Yes
No

Other Modules

STANDBY

Power
Supply

reg33_in

Regulated Output
Voltage

reg33_out

RUN Regulator
ESR: 5m -> 100m Ohms

Voltage Regulator

External Capacitor
typical = 2.2uF

Chip

Figure 36-2. USB Voltage Regulator Block Diagram

This module uses 2 regulators in parallel. In run mode, the RUN regulator with the
bandgap voltage reference is enabled and can provide up to 120 mA load current. In run
mode, the STANDBY regulator and the low power reference are also enabled, but a
switch disconnects its output from the external pin. In STANDBY mode, the RUN
regulator is disabled and the STANDBY regulator output is connected to the external pin.
Internal power mode signals control whether the module is in RUN or STANDBY mode.

36.1.2 Features
• Low drop-out linear voltage regulator with one power channel (3.3V).
• Low drop-out voltage: 300 mV.
• Output current: 120 mA.
• Three different power modes: RUN, STANDBY and SHUTDOWN.
• Low quiescent current in RUN mode.
• Typical value is around 120 uA (one thousand times smaller than the maximum
load current).
• Very low quiescent current in STANDBY mode.
• Typical value is around 1 uA.
• Automatic current limiting if the load current is greater than 290 mA.
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Chapter 36 USB Voltage Regulator

• Automatic power-up once some voltage is applied to the regulator input.
• Pass-through mode for regulator input voltages less than 3.6 V
• Small output capacitor: 2.2 uF
• Stable with aluminum, tantalum or ceramic capacitors.

36.1.3 Modes of Operation
The regulator has these power modes:
• RUN—The regulating loop of the RUN regulator and the STANDBY regulator are
active, but the switch connecting the STANDBY regulator output to the external pin
is open.
• STANDBY—The regulating loop of the RUN regulator is disabled and the standby
regulator is active. The switch connecting the STANDBY regulator output to the
external pin is closed.
• SHUTDOWN—The module is disabled.
The regulator is enabled by default. This means that once the power supply is provided,
the module power-up sequence to RUN mode starts.

36.2 USB Voltage Regulator Module Signal Descriptions
The following table shows the external signals for the regulator.
Table 36-1. USB Voltage Regulator Module Signal Descriptions
Signal
reg33_in
reg33_out

Description

I/O

Unregulated power supply

I

Regulator output voltage

O

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Chapter 37
Serial Peripheral Interface (SPI)
37.1 Introduction
NOTE
For the chip-specific implementation details of this module's
instances see the chip configuration information.
The serial peripheral interface (SPI) module provides for full-duplex, synchronous, serial
communication between the MCU and peripheral devices. These peripheral devices can
include other microcontrollers, analog-to-digital converters, shift registers, sensors, and
memories, among others.
The SPI runs at a baud rate up to the bus clock divided by two in master mode and up to
the bus clock divided by four in slave mode. Software can poll the status flags, or SPI
operation can be interrupt driven.
NOTE
For the actual maximum SPI baud rate, refer to the Chip
Configuration details and to the device’s Data Sheet.
The SPI also includes a hardware match feature for the receive data buffer.
The SPI includes an internal DMA interface to support continuous SPI transmission
through an on-chip DMA controller instead of through the CPU. This feature decreases
CPU loading, allowing CPU time to be used for other work.

37.1.1 Features
The SPI includes these distinctive features:
• Master mode or slave mode operation
• Full-duplex or single-wire bidirectional mode
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Introduction

• Programmable transmit bit rate
• Double-buffered transmit and receive data register
• Serial clock phase and polarity options
• Slave select output
• Mode fault error flag with CPU interrupt capability
• Control of SPI operation during wait mode
• Selectable MSB-first or LSB-first shifting
• Receive data buffer hardware match feature
• Support transmission of both Transmit and Receive by DMA

37.1.2 Modes of Operation
The SPI functions in three modes, run, wait, and stop.
• Run Mode
This is the basic mode of operation.
• Wait Mode
SPI operation in wait mode is a configurable low power mode, controlled by the
SPISWAI bit located in the SPIx_C2 register. In wait mode, if the SPISWAI bit is
clear, the SPI operates like in Run Mode. If the SPISWAI bit is set, the SPI goes into
a power conservative state, with the SPI clock generation turned off. If the SPI is
configured as a master, any transmission in progress stops, but is resumed after CPU
enters run mode. If the SPI is configured as a slave, reception and transmission of a
byte continues, so that the slave stays synchronized to the master.
• Stop Mode
To reduce power consumption, the SPI is inactive in stop modes where the peripheral
bus clock is stopped but internal logic states are retained. If the SPI is configured as a
master, any transmission in progress stops, but is resumed after the CPU enters run
mode. If the SPI is configured as a slave, reception and transmission of a data
continues, so that the slave stays synchronized to the master.

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Chapter 37 Serial Peripheral Interface (SPI)

The SPI is completely disabled in stop modes where the peripheral bus clock is
stopped and internal logic states are not retained. When the CPU wakes from these
stop modes, all SPI register content is reset.
Detailed descriptions of operating modes appear in Low Power Mode Options.

37.1.3 Block Diagrams
This section includes block diagrams showing SPI system connections, the internal
organization of the SPI module, and the SPI clock dividers that control the master mode
bit rate.

37.1.3.1 SPI System Block Diagram
The following figure shows the SPI modules of two MCUs connected in a master-slave
arrangement. The master device initiates all SPI data transfers. During a transfer, the
master shifts data out (on the MOSI pin) to the slave while simultaneously shifting data
in (on the MISO pin) from the slave. The transfer effectively exchanges the data that was
in the SPI shift registers of the two SPI systems. The SPSCK signal is a clock output
from the master and an input to the slave. The slave device must be selected by a low
level on the slave select input (SS pin). In this system, the master device has configured
its SS pin as an optional slave select output.
SLAVE

MASTER
MOSI

MOSI

SPI SHIFTER

8 BITS

SPI SHIFTER
MISO

SPSCK
CLOCK
GENERATOR

SS

MISO

8 BITS

SPSCK

SS

Figure 37-1. SPI System Connections

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37.1.3.2 SPI Module Block Diagram
The following is a block diagram of the SPI module. The central element of the SPI is the
SPI shift register. Data is written to the double-buffered transmitter (write to SPIx_D) and
gets transferred to the SPI shift register at the start of a data transfer. After shifting in 8
bits of data, the data is transferred into the double-buffered receiver where it can be read
from SPIx_D. Pin multiplexing logic controls connections between MCU pins and the
SPI module.
When the SPI is configured as a master, the clock output is routed to the SPSCK pin, the
shifter output is routed to MOSI, and the shifter input is routed from the MISO pin.
When the SPI is configured as a slave, the SPSCK pin is routed to the clock input of the
SPI, the shifter output is routed to MISO, and the shifter input is routed from the MOSI
pin.
In the external SPI system, simply connect all SPSCK pins to each other, all MISO pins
together, and all MOSI pins together. Peripheral devices often use slightly different
names for these pins.

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Chapter 37 Serial Peripheral Interface (SPI)
PIN CONTROL
M

SPE

MOSI
(MOMI)

S
Tx BUFFER (WRITE SPIxD)

ENABLE
SPI SYSTEM

M
SPI SHIFT REGISTER

SHIFT
OUT

SHIFT
IN

Rx BUFFER (READ SPIxD)

MISO
(SISO)

S

SPC0
BIDIROE

LSBFE

SHIFT
DIRECTION

Rx BUFFER Tx BUFFER
SHIFT
FULL
CLOCK
EMPTY

MASTER CLOCK
BUS RATE
CLOCK

CLOCK
LOGIC

SPIBR
CLOCK GENERATOR

MSTR

SLAVE CLOCK

MASTER/SLAVE

M
SPSCK

S
MASTER/
SLAVE

MODE SELECT
MODSSOE

MODE FAULT
DETECTION

RX DMA DONE

SPRF

Rx_DMA REQ

8-BIT COMPARATOR

RXDMAE

SPIxM

TX DMA DONE

SS

SPMF
SPMIE

SPTEF

TX DMA REQ
TXDMAE

SPTIE
MODF
SPIE

INTERRUPT
REQUEST

Figure 37-2. SPI Module Block Diagram without FIFO

37.2 External Signal Description
The SPI optionally shares four port pins. The function of these pins depends on the
settings of SPI control bits. When the SPI is disabled (SPE = 0), these four pins revert to
other functions that are not controlled by the SPI (based on chip configuration).

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37.2.1 SPSCK — SPI Serial Clock
When the SPI is enabled as a slave, this pin is the serial clock input. When the SPI is
enabled as a master, this pin is the serial clock output.

37.2.2 MOSI — Master Data Out, Slave Data In
When the SPI is enabled as a master and SPI pin control zero (SPC0) is 0 (not
bidirectional mode), this pin is the serial data output. When the SPI is enabled as a slave
and SPC0 is 0, this pin is the serial data input. If SPC0 is 1 to select single-wire
bidirectional mode, and master mode is selected, this pin becomes the bidirectional data
I/O pin (MOMI). Also, the bidirectional mode output enable bit determines whether the
pin acts as an input (BIDIROE is 0) or an output (BIDIROE is 1). If SPC0 is 1 and slave
mode is selected, this pin is not used by the SPI and reverts to other functions (based on
chip configuration).

37.2.3 MISO — Master Data In, Slave Data Out
When the SPI is enabled as a master and SPI pin control zero (SPC0) is 0 (not
bidirectional mode), this pin is the serial data input. When the SPI is enabled as a slave
and SPC0 is 0, this pin is the serial data output. If SPC0 is 1 to select single-wire
bidirectional mode, and slave mode is selected, this pin becomes the bidirectional data I/
O pin (SISO), and the bidirectional mode output enable bit determines whether the pin
acts as an input (BIDIROE is 0) or an output (BIDIROE is 1). If SPC0 is 1 and master
mode is selected, this pin is not used by the SPI and reverts to other functions (based on
chip configuration).

37.2.4 SS — Slave Select
When the SPI is enabled as a slave, this pin is the low-true slave select input. When the
SPI is enabled as a master and mode fault enable is off (MODFEN is 0), this pin is not
used by the SPI and reverts to other functions (based on chip configuration). When the
SPI is enabled as a master and MODFEN is 1, the slave select output enable bit
determines whether this pin acts as the mode fault input (SSOE is 0) or as the slave select
output (SSOE is 1).

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37.3 Memory Map and Register Descriptions
The SPI has 8-bit registers to select SPI options, to control baud rate, to report SPI status,
to hold an SPI data match value, and for transmit/receive data.
SPI memory map
Address
offset (hex)

Absolute
address
(hex)

Width
Access
(in bits)

Register name

Reset value

Section/
page

0

4007_6000 SPI control register 1 (SPI0_C1)

8

R/W

04h

37.3.1/661

1

4007_6001 SPI control register 2 (SPI0_C2)

8

R/W

00h

37.3.2/663

2

4007_6002 SPI baud rate register (SPI0_BR)

8

R/W

00h

37.3.3/664

3

4007_6003 SPI status register (SPI0_S)

8

R

20h

37.3.4/665

5

4007_6005 SPI data register (SPI0_D)

8

R/W

00h

37.3.5/667

7

4007_6007 SPI match register (SPI0_M)

8

R/W

00h

37.3.6/668

0

4007_7000 SPI control register 1 (SPI1_C1)

8

R/W

04h

37.3.1/661

1

4007_7001 SPI control register 2 (SPI1_C2)

8

R/W

00h

37.3.2/663

2

4007_7002 SPI baud rate register (SPI1_BR)

8

R/W

00h

37.3.3/664

3

4007_7003 SPI status register (SPI1_S)

8

R

20h

37.3.4/665

5

4007_7005 SPI data register (SPI1_D)

8

R/W

00h

37.3.5/667

7

4007_7007 SPI match register (SPI1_M)

8

R/W

00h

37.3.6/668

37.3.1 SPI control register 1 (SPIx_C1)
This read/write register includes the SPI enable control, interrupt enables, and
configuration options.
Address: 4007_6000h base + 0h offset = 4007_6000h
Bit

Read
Write
Reset

7

6

5

4

3

2

1

0

SPIE

SPE

SPTIE

MSTR

CPOL

CPHA

SSOE

LSBFE

0

0

0

0

0

1

0

0

SPI0_C1 field descriptions
Field
7
SPIE

Description
SPI interrupt enable: for SPRF and MODF
This bit enables the interrupt for SPI receive buffer full (SPRF) and mode fault (MODF) events.
Table continues on the next page...

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SPI0_C1 field descriptions (continued)
Field

Description
0
1

6
SPE

This bit enables the SPI system and dedicates the SPI port pins to SPI system functions. If SPE is
cleared, the SPI is disabled and forced into an idle state, and all status bits in the S register are reset.

This is the interrupt enable bit for SPI transmit buffer empty (SPTEF). An interrupt occurs when the SPI
transmit buffer is empty (SPTEF is set).
Interrupts from SPTEF inhibited (use polling)
When SPTEF is 1, hardware interrupt requested

Master/slave mode select
This bit selects master or slave mode operation.
0
1

3
CPOL

SPI system inactive
SPI system enabled

SPI transmit interrupt enable

0
1
4
MSTR

Request a hardware interrupt when SPRF or MODF is 1

SPI system enable

0
1
5
SPTIE

Interrupts from SPRF and MODF are inhibited—use polling

SPI module configured as a slave SPI device
SPI module configured as a master SPI device

Clock polarity
This bit selects an inverted or non-inverted SPI clock. To transmit data between SPI modules, the SPI
modules must have identical CPOL values.
This bit effectively places an inverter in series with the clock signal either from a master SPI device or to a
slave SPI device. Refer to the description of “SPI Clock Formats” for details.
0
1

2
CPHA

Clock phase
This bit selects one of two clock formats for different kinds of synchronous serial peripheral devices. Refer
to the description of “SPI Clock Formats” for details.
0
1

1
SSOE

Active-high SPI clock (idles low)
Active-low SPI clock (idles high)

First edge on SPSCK occurs at the middle of the first cycle of a data transfer
First edge on SPSCK occurs at the start of the first cycle of a data transfer

Slave select output enable
This bit is used in combination with the mode fault enable (MODFEN) bit in the C2 register and the master/
slave (MSTR) control bit to determine the function of the SS pin.
0

1

When MODFEN is 0: In master mode, SS pin function is general-purpose I/O (not SPI). In slave mode,
SS pin function is slave select input.
When MODFEN is 1: In master mode, SS pin function is SS input for mode fault. In slave mode, SS
pin function is slave select input.
When MODFEN is 0: In master mode, SS pin function is general-purpose I/O (not SPI). In slave mode,
SS pin function is slave select input.
When MODFEN is 1: In master mode, SS pin function is automatic SS output. In slave mode: SS pin
function is slave select input.
Table continues on the next page...

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SPI0_C1 field descriptions (continued)
Field
0
LSBFE

Description
LSB first (shifter direction)
This bit does not affect the position of the MSB and LSB in the data register. Reads and writes of the data
register always have the MSB in bit 7.
0
1

SPI serial data transfers start with most significant bit
SPI serial data transfers start with least significant bit

37.3.2 SPI control register 2 (SPIx_C2)
This read/write register is used to control optional features of the SPI system. Bit 6 is not
implemented and always reads 0.
Address: 4007_6000h base + 1h offset = 4007_6001h
Bit

Read
Write
Reset

7

6

5

4

3

2

1

0

SPMIE

Reserved

TXDMAE

MODFEN

BIDIROE

RXDMAE

SPISWAI

SPC0

0

0

0

0

0

0

0

0

SPI0_C2 field descriptions
Field
7
SPMIE

Description
SPI match interrupt enable
This is the interrupt enable bit for the SPI receive data buffer hardware match (SPMF) function.
0
1

Interrupts from SPMF inhibited (use polling)
When SPMF is 1, requests a hardware interrupt

6
Reserved

This field is reserved.
Do not write to this reserved bit.

5
TXDMAE

Transmit DMA enable
This bit enables a transmit DMA request. When this bit is set to 1, a transmit DMA request is asserted
when both SPTEF and SPE are set, and the interrupt from SPTEF is disabled.
0
1

4
MODFEN

DMA request for transmit is disabled and interrupt from SPTEF is allowed
DMA request for transmit is enabled and interrupt from SPTEF is disabled

Master mode-fault function enable
When the SPI is configured for slave mode, this bit has no meaning or effect. (The SS pin is the slave
select input.) In master mode, this bit determines how the SS pin is used. For details, refer to the
description of the SSOE bit in the C1 register.
0
1

Mode fault function disabled, master SS pin reverts to general-purpose I/O not controlled by SPI
Mode fault function enabled, master SS pin acts as the mode fault input or the slave select output
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SPI0_C2 field descriptions (continued)
Field
3
BIDIROE

Description
Bidirectional mode output enable
When bidirectional mode is enabled, because SPI pin control 0 (SPC0) is set to 1, the BIDIROE bit
determines whether the SPI data output driver is enabled to the single bidirectional SPI I/O pin. Depending
on whether the SPI is configured as a master or a slave, it uses the MOSI (MOMI) or MISO (SISO) pin,
respectively, as the single SPI data I/O pin. When SPC0 is 0, BIDIROE has no meaning or effect.
0
1

2
RXDMAE

Receive DMA enable
This is the enable bit for a receive DMA request. When this bit is set to 1, a receive DMA request is
asserted when both SPRF and SPE are set, and the interrupt from SPRF is disabled.
0
1

1
SPISWAI

DMA request for receive is disabled and interrupt from SPRF is allowed
DMA request for receive is enabled and interrupt from SPRF is disabled

SPI stop in wait mode
This bit is used for power conservation while the device is in wait mode.
0
1

0
SPC0

Output driver disabled so SPI data I/O pin acts as an input
SPI I/O pin enabled as an output

SPI clocks continue to operate in wait mode
SPI clocks stop when the MCU enters wait mode

SPI pin control 0
This bit enables bidirectional pin configurations.
0

SPI uses separate pins for data input and data output (pin mode is normal).
In master mode of operation: MISO is master in and MOSI is master out.

1

In slave mode of operation: MISO is slave out and MOSI is slave in.
SPI configured for single-wire bidirectional operation (pin mode is bidirectional).
In master mode of operation: MISO is not used by SPI; MOSI is master in when BIDIROE is 0 or
master I/O when BIDIROE is 1.
In slave mode of operation: MISO is slave in when BIDIROE is 0 or slave I/O when BIDIROE is 1;
MOSI is not used by SPI.

37.3.3 SPI baud rate register (SPIx_BR)
Use this register to set the prescaler and bit rate divisor for an SPI master. This register
may be read or written at any time.
Address: 4007_6000h base + 2h offset = 4007_6002h
Bit

7

Read
Write
Reset

0
0

6

5

4

3

2

SPPR[2:0]
0

0

1

0

0

0

SPR[3:0]
0

0

0

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SPI0_BR field descriptions
Field

Description

7
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

6–4
SPPR[2:0]

SPI baud rate prescale divisor
This 3-bit field selects one of eight divisors for the SPI baud rate prescaler. The input to this prescaler is
the bus rate clock (BUSCLK). The output of this prescaler drives the input of the SPI baud rate divider.
Refer to the description of “SPI Baud Rate Generation” for details.
000
001
010
011
100
101
110
111

3–0
SPR[3:0]

Baud rate prescaler divisor is 1
Baud rate prescaler divisor is 2
Baud rate prescaler divisor is 3
Baud rate prescaler divisor is 4
Baud rate prescaler divisor is 5
Baud rate prescaler divisor is 6
Baud rate prescaler divisor is 7
Baud rate prescaler divisor is 8

SPI baud rate divisor
This 4-bit field selects one of nine divisors for the SPI baud rate divider. The input to this divider comes
from the SPI baud rate prescaler. Refer to the description of “SPI Baud Rate Generation” for details.
0000
0001
0010
0011
0100
0101
0110
0111
1000
All others

Baud rate divisor is 2
Baud rate divisor is 4
Baud rate divisor is 8
Baud rate divisor is 16
Baud rate divisor is 32
Baud rate divisor is 64
Baud rate divisor is 128
Baud rate divisor is 256
Baud rate divisor is 512
Reserved

37.3.4 SPI status register (SPIx_S)
This register contains read-only status bits. Writes have no meaning or effect.
NOTE
Bits 3 through 0 are not implemented and always read 0.
Address: 4007_6000h base + 3h offset = 4007_6003h
Bit

Read

7

6

5

4

SPRF

SPMF

SPTEF

MODF

0

0

1

0

3

2

1

0

0

0

0

Write
Reset

0

0

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SPI0_S field descriptions
Field
7
SPRF

Description
SPI read buffer full flag
SPRF is set at the completion of an SPI transfer to indicate that received data may be read from the SPI
data (D) register. When the receive DMA request is disabled (RXDMAE is 0), SPRF is cleared by reading
SPRF while it is set and then reading the SPI data register. When the receive DMA request is enabled
(RXDMAE is 1), SPRF is automatically cleared when the DMA transfer for the receive DMA request is
completed (RX DMA Done is asserted).
0
1

6
SPMF

Data available in the receive data buffer

SPI match flag
SPMF is set after SPRF is 1 when the value in the receive data buffer matches the value in the M register.
To clear the flag, read SPMF when it is set and then write a 1 to it.
0
1

5
SPTEF

No data available in the receive data buffer

Value in the receive data buffer does not match the value in the M register
Value in the receive data buffer matches the value in the M register

SPI transmit buffer empty flag
This bit is set when the transmit data buffer is empty. When the transmit DMA request is disabled
(TXDMAE is 0), SPTEF is cleared by reading the S register with SPTEF set and then writing a data value
to the transmit buffer at D. The S register must be read with SPTEF set to 1 before writing data to the D
register; otherwise, the D write is ignored. When the transmit DMA request is enabled (TXDMAE is 1),
SPTEF is automatically cleared when the DMA transfer for the transmit DMA request is completed (TX
DMA Done is asserted). SPTEF is automatically set when all data from the transmit buffer transfers into
the transmit shift register. For an idle SPI, data written to D is transferred to the shifter almost immediately
so that SPTEF is set within two bus cycles, allowing a second set of data to be queued into the transmit
buffer. After completion of the transfer of the data in the shift register, the queued data from the transmit
buffer automatically moves to the shifter, and SPTEF is set to indicate that room exists for new data in the
transmit buffer. If no new data is waiting in the transmit buffer, SPTEF simply remains set and no data
moves from the buffer to the shifter.
If a transfer does not stop, the last data that was transmitted is sent out again.
0
1

4
MODF

SPI transmit buffer empty

Master mode fault flag
MODF is set if the SPI is configured as a master and the slave select input goes low, indicating some
other SPI device is also configured as a master. The SS pin acts as a mode fault error input only when
MSTR is 1, MODFEN is 1, and SSOE is 0; otherwise, MODF will never be set. MODF is cleared by
reading MODF while it is 1 and then writing to the SPI control register 1 (C1).
0
1

3–0
Reserved

SPI transmit buffer not empty

No mode fault error
Mode fault error detected

This field is reserved.
This read-only field is reserved and always has the value 0.

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Chapter 37 Serial Peripheral Interface (SPI)

37.3.5 SPI data register (SPIx_D)
This register is both the input and output register for SPI data. A write to the register
writes to the transmit data buffer, allowing data to be queued and transmitted.
When the SPI is configured as a master, data queued in the transmit data buffer is
transmitted immediately after the previous transmission has completed.
The SPTEF bit in the S register indicates when the transmit data buffer is ready to accept
new data. When the transmit DMA request is disabled (TXDMAE is 0): The S register
must be read when SPTEF is set before writing to the SPI data register; otherwise, the
write is ignored. When the transmit DMA request is enabled (TXDMAE is 1) when
SPTEF is set, the SPI data register can be written automatically by DMA without reading
the S register first.
Data may be read from the SPI data register any time after SPRF is set and before another
transfer is finished. Failure to read the data out of the receive data buffer before a new
transfer ends causes a receive overrun condition, and the data from the new transfer is
lost. The new data is lost because the receive buffer still held the previous character and
was not ready to accept the new data. There is no indication for a receive overrun
condition, so the application system designer must ensure that previous data has been
read from the receive buffer before a new transfer is initiated.
Address: 4007_6000h base + 5h offset = 4007_6005h
Bit

Read
Write
Reset

7

6

5

4

3

2

1

0

0

0

0

0

Bits[7:0]
0

0

0

0

SPI0_D field descriptions
Field
7–0
Bits[7:0]

Description
Data (low byte)

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Functional Description

37.3.6 SPI match register (SPIx_M)
This register contains the hardware compare value. When the value received in the SPI
receive data buffer equals this hardware compare value, the SPI match flag (SPMF) sets.
Address: 4007_6000h base + 7h offset = 4007_6007h
Bit

Read
Write
Reset

7

6

5

4

3

2

1

0

0

0

0

0

Bits[7:0]
0

0

0

0

SPI0_M field descriptions
Field
7–0
Bits[7:0]

Description
Hardware compare value (low byte)

37.4 Functional Description
This section provides the functional description of the module.

37.4.1 General
The SPI system is enabled by setting the SPI enable (SPE) bit in SPI Control Register 1.
While the SPE bit is set, the four associated SPI port pins are dedicated to the SPI
function as:
• Slave select (SS)
• Serial clock (SPSCK)
• Master out/slave in (MOSI)
• Master in/slave out (MISO)
An SPI transfer is initiated in the master SPI device by reading the SPI status register
(SPIx_S) when SPTEF = 1 and then writing data to the transmit data buffer (write to
SPIxD ). When a transfer is complete, received data is moved into the receive data buffer.
The SPIxD register acts as the SPI receive data buffer for reads and as the SPI transmit
data buffer for writes.
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Chapter 37 Serial Peripheral Interface (SPI)

The clock phase control bit (CPHA) and clock polarity control bit (CPOL) in the SPI
Control Register 1 (SPIx_C1) select one of four possible clock formats to be used by the
SPI system. The CPOL bit simply selects a non-inverted or inverted clock. The CPHA bit
is used to accommodate two fundamentally different protocols by sampling data on odd
numbered SPSCK edges or on even numbered SPSCK edges.
The SPI can be configured to operate as a master or as a slave. When the MSTR bit in
SPI Control Register 1 is set, master mode is selected; when the MSTR bit is clear, slave
mode is selected.

37.4.2 Master Mode
The SPI operates in master mode when the MSTR bit is set. Only a master SPI module
can initiate transmissions. A transmission begins by reading the SPIx_S register while
SPTEF = 1 and writing to the master SPI data registers. If the shift register is empty, the
byte immediately transfers to the shift register. The data begins shifting out on the MOSI
pin under the control of the serial clock.
• SPSCK
• The SPR3, SPR2, SPR1, and SPR0 baud rate selection bits in conjunction with
the SPPR2, SPPR1, and SPPR0 baud rate preselection bits in the SPI Baud Rate
register control the baud rate generator and determine the speed of the
transmission. The SPSCK pin is the SPI clock output. Through the SPSCK pin,
the baud rate generator of the master controls the shift register of the slave
peripheral.
• MOSI, MISO pin
• In master mode, the function of the serial data output pin (MOSI) and the serial
data input pin (MISO) is determined by the SPC0 and BIDIROE control bits.
• SS pin
• If MODFEN and SSOE bit are set, the SS pin is configured as slave select
output. The SS output becomes low during each transmission and is high when
the SPI is in idle state. If MODFEN is set and SSOE is cleared, the SS pin is
configured as input for detecting mode fault error. If the SS input becomes low
this indicates a mode fault error where another master tries to drive the MOSI
and SPSCK lines. In this case, the SPI immediately switches to slave mode by
clearing the MSTR bit and also disables the slave output buffer MISO (or SISO
in bidirectional mode). As a result, all outputs are disabled, and SPSCK, MOSI
and MISO are inputs. If a transmission is in progress when the mode fault
occurs, the transmission is aborted and the SPI is forced into idle state. This
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mode fault error also sets the mode fault (MODF) flag in the SPI Status Register
(SPIx_S). If the SPI interrupt enable bit (SPIE) is set when the MODF flag gets
set, then an SPI interrupt sequence is also requested. When a write to the SPI
Data Register in the master occurs, there is a half SPSCK-cycle delay. After the
delay, SPSCK is started within the master. The rest of the transfer operation
differs slightly, depending on the clock format specified by the SPI clock phase
bit, CPHA, in SPI Control Register 1 (see SPI Clock Formats).
Note
A change of the bits CPOL, CPHA, SSOE, LSBFE, MODFEN,
SPC0, BIDIROE with SPC0 set, SPPR2-SPPR0 and SPR3SPR0 in master mode abort a transmission in progress and force
the SPI into idle state. The remote slave cannot detect this,
therefore the master has to ensure that the remote slave is set
back to idle state.

37.4.3 Slave Mode
The SPI operates in slave mode when the MSTR bit in SPI Control Register1 is clear.
• SPSCK
In slave mode, SPSCK is the SPI clock input from the master.
• MISO, MOSI pin
In slave mode, the function of the serial data output pin (MISO) and serial data input
pin (MOSI) is determined by the SPC0 bit and BIDIROE bit in SPI Control Register
2.
• SS pin
The SS pin is the slave select input. Before a data transmission occurs, the SS pin of
the slave SPI must be low. SS must remain low until the transmission is complete. If
SS goes high, the SPI is forced into an idle state.
The SS input also controls the serial data output pin. If SS is high (not selected), the
serial data output pin is high impedance. If SS is low, the first bit in the SPI Data
Register is driven out of the serial data output pin. Also, if the slave is not selected
(SS is high), then the SPSCK input is ignored and no internal shifting of the SPI shift
register occurs.

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Although the SPI is capable of duplex operation, some SPI peripherals are capable of
only receiving SPI data in a slave mode. For these simpler devices, there is no serial
data out pin.
Note
When peripherals with duplex capability are used, take care not
to simultaneously enable two receivers whose serial outputs
drive the same system slave's serial data output line.
As long as no more than one slave device drives the system slave's serial data output line,
it is possible for several slaves to receive the same transmission from a master, although
the master would not receive return information from all of the receiving slaves.
If the CPHA bit in SPI Control Register 1 is clear, odd numbered edges on the SPSCK
input cause the data at the serial data input pin to be latched. Even numbered edges cause
the value previously latched from the serial data input pin to shift into the LSB or MSB
of the SPI shift register, depending on the LSBFE bit.
If the CPHA bit is set, even numbered edges on the SPSCK input cause the data at the
serial data input pin to be latched. Odd numbered edges cause the value previously
latched from the serial data input pin to shift into the LSB or MSB of the SPI shift
register, depending on the LSBFE bit.
When CPHA is set, the first edge is used to get the first data bit onto the serial data output
pin. When CPHA is clear and the SS input is low (slave selected), the first bit of the SPI
data is driven out of the serial data output pin. After the eighth shift, the transfer is
considered complete and the received data is transferred into the SPI Data register. To
indicate transfer is complete, the SPRF flag in the SPI Status Register is set.
Note
A change of the bits BIDIROE with SPC0 set, CPOL, CPHA,
SSOE, LSBFE, MODFEN, and SPC0 in slave mode will
corrupt a transmission in progress and must be avoided.

37.4.4 SPI Transmission by DMA
SPI supports both Transmit and Receive by DMA. The basic flow of SPI transmission by
DMA is as below.

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RESET

Configure DMA Controller
for SPI Transmission

Configure SPI before Transmission

Set TXDMAE/RXDMAE=1 to enable
Transmit/Receive by DMA

Set SPE=1 to start transmission in
master mode or enable SPI for
transmission in slave moe
Wait for interrupt(s) of DMA Controller
indicating end of SPI transmission

Figure 37-21. Basic Flow of SPI Transmission by DMA

37.4.4.1 Transmit by DMA
Transmit by DMA is supported only when TXDMAE is set. A transmit DMA request is
asserted when both SPE and SPTEF are set. Then the on-chip DMA controller detects
this request and transfers data from memory into the SPI data register. After that, TX
DMA DONE is asserted to clear SPTEF automatically. This process repeats until all data
for transmission (the number is decided by the configuration register[s] of the DMA
controller) is sent.
After DMA transfers the first byte to the SPI data register, the SPI pushes this data into
the shifter, thereby making SPTEF high again. This generates another DMA request
immediately, but the CPU lacks enough time to service the first DMA interrupt service
request (ISR). The subsequent DMA request is paced at the SPI transfer rate. Manage this
behavior during the first byte transfer through the DMA channel. Write the first byte to
the SPI data register via the CPU. The other bytes are transmitted by the DMA.

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Chapter 37 Serial Peripheral Interface (SPI)
RESET

Configure DMA Controller
for SPI transmission

Configure SPI before Transmission

Set SPE=1 to start transmission in
master mode or enable SPI for
transmission in slave mode

Read SPI status register

Write the first byte to SPI data register
via CPU

Set TXDMAE to enable Transmit by
DMA

Wait for interrupt(s) of DMA Controller
indicating end of SPI transmission

Figure 37-22. Recommended startup of SPI transmit by DMA

37.4.4.2 Receive by DMA
Receive by DMA is supported only when RXDMAE is set. A receive DMA request is
asserted when both SPE and SPRF are set. Then the on-chip DMA controller detects this
request and transfers data from the SPI data register into memory. After that, RX DMA
DONE is asserted to clear SPRF automatically. This process repeats until all data to be
received (the number is decided by configuration register[s] of the DMA controller) is
received or no receive DMA request is generated again because the SPI transmission is
finished.

37.4.5 SPI Clock Formats
To accommodate a wide variety of synchronous serial peripherals from different
manufacturers, the SPI system has a clock polarity (CPOL) bit and a clock phase (CPHA)
control bit to select one of four clock formats for data transfers. CPOL selectively inserts
an inverter in series with the clock. CPHA chooses between two different clock phase
relationships between the clock and data.
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The following figure shows the clock formats when CPHA = 1. At the top of the figure,
the eight bit times are shown for reference with bit 1 starting at the first SPSCK edge and
bit 8 ending one-half SPSCK cycle after the eighth SPSCK edge. The MSB first and LSB
first lines show the order of SPI data bits depending on the setting in LSBFE. Both
variations of SPSCK polarity are shown, but only one of these waveforms applies for a
specific transfer, depending on the value in CPOL. The SAMPLE IN waveform applies
to the MOSI input of a slave or the MISO input of a master. The MOSI waveform applies
to the MOSI output pin from a master and the MISO waveform applies to the MISO
output from a slave. The SS OUT waveform applies to the slave select output from a
master (provided MODFEN and SSOE = 1). The master SS output goes to active low
one-half SPSCK cycle before the start of the transfer and goes back high at the end of the
eighth bit time of the transfer. The SS IN waveform applies to the slave select input of a
slave.
BIT TIME #
(REFERENCE)

1

2

...

6

8

7

SPSCK
(CPOL = 0)

SPSCK
(CPOL = 1)

SAMPLE IN
(MISO OR MOSI)

MOSI
(MASTER OUT)
MSB FIRST
LSB FIRST

BIT 7
BIT 0

BIT 6
BIT 1

...
...

BIT 2
BIT 5

BIT 1
BIT 6

BIT 0
BIT 7

MISO
(SLAVE OUT)

SS OUT
(MASTER)

SS IN
(SLAVE)

Figure 37-23. SPI Clock Formats (CPHA = 1)

When CPHA = 1, the slave begins to drive its MISO output when SS goes to active low,
but the data is not defined until the first SPSCK edge. The first SPSCK edge shifts the
first bit of data from the shifter onto the MOSI output of the master and the MISO output
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Chapter 37 Serial Peripheral Interface (SPI)

of the slave. The next SPSCK edge causes both the master and the slave to sample the
data bit values on their MISO and MOSI inputs, respectively. At the third SPSCK edge,
the SPI shifter shifts one bit position which shifts in the bit value that was just sampled,
and shifts the second data bit value out the other end of the shifter to the MOSI and
MISO outputs of the master and slave, respectively.
When CPHA = 1, the slave's SS input is not required to go to its inactive high level
between transfers. In this clock format, a back-to-back transmission can occur, as
follows:
1. A transmission is in progress.
2. A new data byte is written to the transmit buffer before the in-progress transmission
is complete.
3. When the in-progress transmission is complete, the new, ready data byte is
transmitted immediately.
Between these two successive transmissions, no pause is inserted; the SS pin remains
low.
The following figure shows the clock formats when CPHA = 0. At the top of the figure,
the eight bit times are shown for reference with bit 1 starting as the slave is selected (SS
IN goes low), and bit 8 ends at the last SPSCK edge. The MSB first and LSB first lines
show the order of SPI data bits depending on the setting in LSBFE. Both variations of
SPSCK polarity are shown, but only one of these waveforms applies for a specific
transfer, depending on the value in CPOL. The SAMPLE IN waveform applies to the
MOSI input of a slave or the MISO input of a master. The MOSI waveform applies to the
MOSI output pin from a master and the MISO waveform applies to the MISO output
from a slave. The SS OUT waveform applies to the slave select output from a master
(provided MODFEN and SSOE = 1). The master SS output goes to active low at the start
of the first bit time of the transfer and goes back high one-half SPSCK cycle after the end
of the eighth bit time of the transfer. The SS IN waveform applies to the slave select input
of a slave.

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BIT TIME #
(REFERENCE)

1

2

...

6

7

8

SPSCK
(CPOL = 0)

SPSCK
(CPOL = 1)

SAMPLE IN
(MISO OR MOSI)

MOSI
(MASTER OUT)
MSB FIRST
LSB FIRST

BIT 7
BIT 0

BIT 6
BIT 1

...
...

BIT 2
BIT 5

BIT 1
BIT 6

BIT 0
BIT 7

MISO
(SLAVE OUT)

SS OUT
(MASTER)

SS IN
(SLAVE)

Figure 37-24. SPI Clock Formats (CPHA = 0)

When CPHA = 0, the slave begins to drive its MISO output with the first data bit value
(MSB or LSB depending on LSBFE) when SS goes to active low. The first SPSCK edge
causes both the master and the slave to sample the data bit values on their MISO and
MOSI inputs, respectively. At the second SPSCK edge, the SPI shifter shifts one bit
position which shifts in the bit value that was just sampled and shifts the second data bit
value out the other end of the shifter to the MOSI and MISO outputs of the master and
slave, respectively. When CPHA = 0, the slave's SS input must go to its inactive high
level between transfers.

37.4.6 SPI Baud Rate Generation
As shown in the following figure, the clock source for the SPI baud rate generator is the
bus clock. The three prescale bits (SPPR2:SPPR1:SPPR0) choose a prescale divisor of 1,
2, 3, 4, 5, 6, 7, or 8. The three rate select bits (SPR3:SPR2:SPR1:SPR0) divide the output
of the prescaler stage by 2, 4, 8, 16, 32, 64, 128, 256, or 512 to get the internal SPI master
mode bit-rate clock.

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The baud rate generator is activated only when the SPI is in the master mode and a serial
transfer is taking place. In the other cases, the divider is disabled to decrease IDD current.
The baud rate divisor equation is as follows (except those reserved combinations in the
SPI Baud Rate Divisor table).
BaudRateDivisor = (SPPR + 1) × 2(SPR

+ 1)

The baud rate can be calculated with the following equation:
BaudRate = BusClock / BaudRateDivisor

BUS
CLOCK

PRESCALER

BAUD RATE DIVIDER

DIVIDE BY
1, 2, 3, 4, 5, 6, 7, or 8

DIVIDE BY
2, 4, 8, 16, 32, 64, 128,
256, or 512

SPPR2:SPPR1:SPPR0

SPR3:SPR2:SPR1:SPR0

MASTER
SPI
BIT RATE

Figure 37-25. SPI Baud Rate Generation

37.4.7 Special Features
The following section shows the module special features.

37.4.7.1 SS Output
The SS output feature automatically drives the SS pin low during transmission to select
external devices and drives the SS pin high during idle to deselect external devices. When
the SS output is selected, the SS output pin is connected to the SS input pin of the
external device.
The SS output is available only in master mode during normal SPI operation by asserting
the SSOE and MODFEN bits as shown in the description of the C1[SSOE] bit.
The mode fault feature is disabled while SS output is enabled.
Note
Be careful when using the SS output feature in a multimaster
system because the mode fault feature is not available for
detecting system errors between masters.

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37.4.7.2 Bidirectional Mode (MOMI or SISO)
The bidirectional mode is selected when the SPC0 bit is set in SPI Control Register 2 (see
the following table). In this mode, the SPI uses only one serial data pin for the interface
with one or more external devices. The MSTR bit decides which pin to use. The MOSI
pin becomes the serial data I/O (MOMI) pin for the master mode, and the MISO pin
becomes serial data I/O (SISO) pin for the slave mode. The MISO pin in master mode
and MOSI pin in slave mode are not used by the SPI.
Table 37-22. Normal Mode and Bidirectional Mode
When SPE = 1

Master Mode MSTR = 1
Serial Out

Normal Mode
SPC0 = 0

Bidirectional Mode
SPC0 = 1

Slave Mode MSTR = 0
MOSI

SPI

SPI

Serial In

MISO

Serial Out

Serial Out

MOMI

Serial In

SPI

MOSI

Serial In

SPI

BIDIROE

Serial In

MISO

BIDIROE

Serial Out

SISO

The direction of each serial I/O pin depends on the BIDIROE bit. If the pin is configured
as an output, serial data from the shift register is driven out on the pin. The same pin is
also the serial input to the shift register.
The SPSCK is an output for the master mode and an input for the slave mode.
SS is the input or output for the master mode, and it is always the input for the slave
mode.
The bidirectional mode does not affect SPSCK and SS functions.
Note
In bidirectional master mode, with the mode fault feature
enabled, both data pins MISO and MOSI can be occupied by
the SPI, though MOSI is normally used for transmissions in
bidirectional mode and MISO is not used by the SPI. If a mode
fault occurs, the SPI is automatically switched to slave mode. In
this case, MISO becomes occupied by the SPI and MOSI is not
used. Consider this scenario if the MISO pin is used for another
purpose.

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37.4.8 Error Conditions
The SPI module has one error condition: the mode fault error.

37.4.8.1 Mode Fault Error
If the SS input becomes low while the SPI is configured as a master, it indicates a system
error where more than one master may be trying to drive the MOSI and SPSCK lines
simultaneously. This condition is not permitted in normal operation, and it sets the
MODF bit in the SPI status register automatically provided that the MODFEN bit is set.
In the special case where the SPI is in master mode and the MODFEN bit is cleared, the
SS pin is not used by the SPI. In this special case, the mode fault error function is
inhibited and MODF remains cleared. If the SPI system is configured as a slave, the SS
pin is a dedicated input pin. A mode fault error does not occur in slave mode.
If a mode fault error occurs, the SPI is switched to slave mode, with the exception that
the slave output buffer is disabled. So the SPSCK, MISO and MOSI pins are forced to be
high impedance inputs to avoid any possibility of conflict with another output driver. A
transmission in progress is aborted and the SPI is forced into idle state.
If the mode fault error occurs in the bidirectional mode for an SPI system configured in
master mode, the output enable of MOMI (MOSI in bidirectional mode) is cleared if it
was set. No mode fault error occurs in the bidirectional mode for the SPI system
configured in slave mode.
The mode fault flag is cleared automatically by a read of the SPI Status Register (with
MODF set) followed by a write to SPI Control Register 1. If the mode fault flag is
cleared, the SPI becomes a normal master or slave again.

37.4.9 Low Power Mode Options
This section describes the low power mode options.

37.4.9.1 SPI in Run Mode
In run mode, with the SPI system enable (SPE) bit in the SPI control register clear, the
SPI system is in a low-power, disabled state. SPI registers can still be accessed, but
clocks to the core of this module are disabled.

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37.4.9.2 SPI in Wait Mode
SPI operation in wait mode depends upon the state of the SPISWAI bit in SPI Control
Register 2.
• If SPISWAI is clear, the SPI operates normally when the CPU is in wait mode.
• If SPISWAI is set, SPI clock generation ceases and the SPI module enters a power
conservation state when the CPU is in wait mode.
• If SPISWAI is set and the SPI is configured for master, any transmission and
reception in progress stops at wait mode entry. The transmission and reception
resumes when the SPI exits wait mode.
• If SPISWAI is set and the SPI is configured as a slave, any transmission and
reception in progress continues if the SPSCK continues to be driven from the
master. This keeps the slave synchronized to the master and the SPSCK.
If the master transmits data while the slave is in wait mode, the slave continues
to send data consistent with the operation mode at the start of wait mode (that is,
if the slave is currently sending its SPIx_D to the master, it continues to send the
same byte. Otherwise, if the slave is currently sending the last data received byte
from the master, it continues to send each previously received data from the
master byte).
Note
Care must be taken when expecting data from a master while
the slave is in a wait mode or a stop mode where the peripheral
bus clock is stopped but internal logic states are retained. Even
though the shift register continues to operate, the rest of the SPI
is shut down (that is, an SPRF interrupt is not generated until an
exit from stop or wait mode). Also, the data from the shift
register is not copied into the SPIx_D registers until after the
slave SPI has exited wait or stop mode. An SPRF flag and
SPIx_D copy is only generated if wait mode is entered or exited
during a transmission. If the slave enters wait mode in idle
mode and exits wait mode in idle mode, neither an SPRF nor a
SPIx_D copy occurs.

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37.4.9.3 SPI in Stop Mode
Operation in a stop mode where the peripheral bus clock is stopped but internal logic
states are retained depends on the SPI system. The stop mode does not depend on the
SPISWAI bit. Upon entry to this type of stop mode, the SPI module clock is disabled
(held high or low).
• If the SPI is in master mode and exchanging data when the CPU enters the stop
mode, the transmission is frozen until the CPU exits stop mode. After the exit from
stop mode, data to and from the external SPI is exchanged correctly.
• In slave mode, the SPI remains synchronized with the master.
The SPI is completely disabled in a stop mode where the peripheral bus clock is stopped
and internal logic states are not retained. After an exit from this type of stop mode, all
registers are reset to their default values, and the SPI module must be re-initialized.

37.4.10 Reset
The reset values of registers and signals are described in the Memory Map and Register
Descriptions content, which details the registers and their bitfields.
• If a data transmission occurs in slave mode after a reset without a write to SPIx_D,
the transmission consists of "garbage" or the data last received from the master
before the reset.
• Reading from SPIx_D after reset always returns zeros.

37.4.11 Interrupts
The SPI originates interrupt requests only when the SPI is enabled (the SPE bit in the
SPIx_C1 register is set). The following is a description of how the SPI makes a request
and how the MCU should acknowledge that request. The interrupt vector offset and
interrupt priority are chip dependent.
Four flag bits, three interrupt mask bits, and one interrupt vector are associated with the
SPI system. The SPI interrupt enable mask (SPIE) enables interrupts from the SPI
receiver full flag (SPRF) and mode fault flag (MODF). The SPI transmit interrupt enable
mask (SPTIE) enables interrupts from the SPI transmit buffer empty flag (SPTEF). The
SPI match interrupt enable mask bit (SPIMIE) enables interrupts from the SPI match flag
(SPMF). When one of the flag bits is set, and the associated interrupt mask bit is set, a
hardware interrupt request is sent to the CPU. If the interrupt mask bits are cleared,
software can poll the associated flag bits instead of using interrupts. The SPI interrupt
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service routine (ISR) should check the flag bits to determine which event caused the
interrupt. The service routine should also clear the flag bit(s) before returning from the
ISR (usually near the beginning of the ISR).

37.4.11.1 MODF
MODF occurs when the master detects an error on the SS pin. The master SPI must be
configured for the MODF feature (see the description of the C1[SSOE] bit). Once MODF
is set, the current transfer is aborted and the master (MSTR) bit in the SPIx_C1 register
resets to 0.
The MODF interrupt is reflected in the status register's MODF flag. Clearing the flag also
clears the interrupt. This interrupt stays active while the MODF flag is set. MODF has an
automatic clearing process that is described in the SPI Status Register.

37.4.11.2 SPRF
SPRF occurs when new data has been received and copied to the SPI receive data buffer.
After SPRF is set, it does not clear until it is serviced. SPRF has an automatic clearing
process that is described in the SPI Status Register details. If the SPRF is not serviced
before the end of the next transfer (that is, SPRF remains active throughout another
transfer), the subsequent transfers are ignored and no new data is copied into the Data
register.

37.4.11.3 SPTEF
SPTEF occurs when the SPI transmit buffer is ready to accept new data.
After SPTEF is set, it does not clear until it is serviced. SPTEF has an automatic clearing
process that is described in the SPI Status Register details.

37.4.11.4 SPMF
SPMF occurs when the data in the receive data buffer is equal to the data in the SPI
match register.

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37.4.11.5 Asynchronous interrupt in low power modes
When the CPU is in wait mode or stop mode and the SPI module receives a transmission,
the SPI module can generate an asynchronous interrupt to wake the CPU from the low
power mode. The module generates the asynchronous interrupt only when all of the
following conditions apply:
1. The C1[SPIE] bit is set to 1.
2. The CPU is in wait mode—in which case the C2[SPISWAI] bit must be 1—or in
stop mode where the peripheral bus clock is stopped but internal logic states are
retained.
3. The SPI module is in slave mode.
4. The received transmission ends.
After the interrupt wakes the CPU and the peripheral bus clock is active again, the SPI
module copies the received data from the shifter into the Data register and generates flags
or DMA request signals. During the wakeup phase, a continuous transmission from a
master would destroy the first received data.

37.5 Initialization/Application Information
This section discusses an example of how to initialize and use the SPI.

37.5.1 Initialization Sequence
Before the SPI module can be used for communication, an initialization procedure must
be carried out, as follows:
1. Update control register 1 (SPIx_C1) to enable the SPI and to control interrupt
enables. This register also sets the SPI as master or slave, determines clock phase and
polarity, and configures the main SPI options.
2. Update control register 2 (SPIx_C2) to enable additional SPI functions such as the
SPI match interrupt feature, the master mode-fault function, and bidirectional mode
output as well as to control and other optional features.
3. Update the baud rate register (SPIx_BR) to set the prescaler and bit rate divisor for
an SPI master.
4. Update the hardware match register (SPIx_M) with the value to be compared to the
receive data register for triggering an interrupt if hardware match interrupts are
enabled.

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5. In the master, read SPIx_S while SPTEF = 1, and then write to the transmit data
register (SPIx_D) to begin transfer.

37.5.2 Pseudo-Code Example
In this example, the SPI module is set up for master mode with only hardware match
interrupts enabled. The SPI runs at a maximum baud rate of bus clock divided by 2.
Clock phase and polarity are set for an active-high SPI clock where the first edge on
SPSCK occurs at the start of the first cycle of a data transfer.
SPIx_C1=0x54(%01010100)
Bit 7

SPIE

=

0

Disables receive and mode fault interrupts

Bit 6

SPE

=

1

Enables the SPI system

Bit 5

SPTIE

=

0

Disables SPI transmit interrupts

Bit 4

MSTR

=

1

Sets the SPI module as a master SPI device

Bit 3

CPOL

=

0

Configures SPI clock as active-high

Bit 2

CPHA

=

1

First edge on SPSCK at start of first data transfer cycle

Bit 1

SSOE

=

0

Determines SS pin function when mode fault enabled

Bit 0

LSBFE

=

0

SPI serial data transfers start with most significant bit

SPMIE

=

1

SPI hardware match interrupt enabled

=

0

Unimplemented

SPIx_C2 = 0x80(%10000000)
Bit 7
Bit 6
Bit 5

TXDMAE

=

0

DMA request disabled

Bit 4

MODFEN

=

0

Disables mode fault function

Bit 3

BIDIROE

=

0

SPI data I/O pin acts as input

Bit 2

RXDMAE

=

0

DMA request disabled

Bit 1

SPISWAI

=

0

SPI clocks operate in wait mode

Bit 0

SPC0

=

0

uses separate pins for data input and output

Bit 7

=

0

Reserved

Bit 6:4

=

000

Sets prescale divisor to 1

Bit 3:0

=

0000 Sets baud rate divisor to 2

SPIx_BR = 0x00(%00000000)

SPIx_S = 0x00(%00000000)
Bit 7

SPRF

=

0

Flag is set when receive data buffer is full

Bit 6

SPMF

=

0

Flag is set when SPIx_M = receive data buffer

Table continues on the next page...

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SPIx_S = 0x00(%00000000)
Bit 5

SPTEF

=

0

Flag is set when transmit data buffer is empty

Bit 4

MODF

=

0

Mode fault flag for master mode

=

0

Reserved

Bit 3:0

SPIx_M = 0xXX
Holds bits 0–7 of the hardware match buffer.

SPIx_D = 0xxx
Holds bits 0–7 of the data to be transmitted by the transmit buffer and received by the receive buffer.

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Initialization/Application Information
RESET

INITIALIZE SPI
SPIxC1 = 0x54
SPIxC2 = 0x80
SPIxBR = 0x00

YES
SPTEF = 1
?

NO

YES
WRITE TO

SPIxD

SPRF = 1
?

NO

YES
READ

SPIxD

SPMF = 1
?

NO

YES
READ SPMF WHILE SET
TO CLEAR FLAG,
THEN WRITE A 1 TO IT

CONTINUE

Figure 37-26. Initialization Flowchart Example for SPI Master Device

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Chapter 38
Inter-Integrated Circuit (I2C)
38.1 Introduction
NOTE
For the chip-specific implementation details of this module's
instances see the chip configuration information.
The inter-integrated circuit (I2C, I2C, or IIC) module provides a method of
communication between a number of devices. The interface is designed to operate up to
100 kbit/s with maximum bus loading and timing. The I2C device is capable of operating
at higher baud rates, up to a maximum of clock/20, with reduced bus loading. The
maximum communication length and the number of devices that can be connected are
limited by a maximum bus capacitance of 400 pF. The I2C module also complies with
the System Management Bus (SMBus) Specification, version 2.

38.1.1 Features
The I2C module has the following features:
•
•
•
•
•
•
•
•
•
•
•
•

Compatible with The I2C-Bus Specification
Multimaster operation
Software programmable for one of 64 different serial clock frequencies
Software-selectable acknowledge bit
Interrupt-driven byte-by-byte data transfer
Arbitration-lost interrupt with automatic mode switching from master to slave
Calling address identification interrupt
START and STOP signal generation and detection
Repeated START signal generation and detection
Acknowledge bit generation and detection
Bus busy detection
General call recognition
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Introduction

•
•
•
•
•
•

10-bit address extension
Support for System Management Bus (SMBus) Specification, version 2
Programmable glitch input filter
Low power mode wakeup on slave address match
Range slave address support
DMA support

38.1.2 Modes of operation
The I2C module's operation in various low power modes is as follows:
• Run mode: This is the basic mode of operation. To conserve power in this mode,
disable the module.
• Wait mode: The module continues to operate when the core is in Wait mode and can
provide a wakeup interrupt.
• Stop mode: The module is inactive in Stop mode for reduced power consumption,
except that address matching is enabled in Stop mode. The STOP instruction does
not affect the I2C module's register states.

38.1.3 Block diagram
The following figure is a functional block diagram of the I2C module.

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Chapter 38 Inter-Integrated Circuit (I2C)

Address

Module Enable

Write/Read
Interrupt

ADDR_DECODE

DATA_MUX

CTRL_REG FREQ_REG ADDR_REG

STATUS_REG

DATA_REG

Input
Sync
START
STOP
Arbitration
Control
Clock
Control

In/Out
Data
Shift
Register

Address
Compare

SDA

SCL

Figure 38-1. I2C Functional block diagram

38.2 I2C signal descriptions
The signal properties of I2C are shown in the following table.
Table 38-1. I2C signal descriptions
Signal
SCL
SDA

Description

I/O

Bidirectional serial clock line of the
Bidirectional serial data line of the

I2C

I2C

system.

system.

I/O
I/O

38.3 Memory map and register descriptions
This section describes in detail all I2C registers accessible to the end user.
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Memory map and register descriptions

I2C memory map
Absolute
address
(hex)

Width
Access
(in bits)

Register name

Reset value

Section/
page

4006_6000

I2C Address Register 1 (I2C0_A1)

8

R/W

00h

38.3.1/690

4006_6001

I2C Frequency Divider register (I2C0_F)

8

R/W

00h

38.3.2/691

4006_6002

I2C Control Register 1 (I2C0_C1)

8

R/W

00h

38.3.3/692

4006_6003

I2C Status register (I2C0_S)

8

R/W

80h

38.3.4/694

4006_6004

I2C Data I/O register (I2C0_D)

8

R/W

00h

38.3.5/695

4006_6005

I2C Control Register 2 (I2C0_C2)

8

R/W

00h

38.3.6/696

4006_6006

I2C Programmable Input Glitch Filter register (I2C0_FLT)

8

R/W

00h

38.3.7/697

4006_6007

I2C Range Address register (I2C0_RA)

8

R/W

00h

38.3.8/698

4006_6008

I2C SMBus Control and Status register (I2C0_SMB)

8

R/W

00h

38.3.9/699

4006_6009

I2C Address Register 2 (I2C0_A2)

8

R/W

C2h

38.3.10/
701

4006_600A

I2C SCL Low Timeout Register High (I2C0_SLTH)

8

R/W

00h

38.3.11/
701

4006_600B

I2C SCL Low Timeout Register Low (I2C0_SLTL)

8

R/W

00h

38.3.12/
701

4006_7000

I2C Address Register 1 (I2C1_A1)

8

R/W

00h

38.3.1/690

4006_7001

I2C Frequency Divider register (I2C1_F)

8

R/W

00h

38.3.2/691

4006_7002

I2C Control Register 1 (I2C1_C1)

8

R/W

00h

38.3.3/692

4006_7003

I2C Status register (I2C1_S)

8

R/W

80h

38.3.4/694

4006_7004

I2C Data I/O register (I2C1_D)

8

R/W

00h

38.3.5/695

4006_7005

I2C Control Register 2 (I2C1_C2)

8

R/W

00h

38.3.6/696

4006_7006

I2C Programmable Input Glitch Filter register (I2C1_FLT)

8

R/W

00h

38.3.7/697

4006_7007

I2C Range Address register (I2C1_RA)

8

R/W

00h

38.3.8/698

4006_7008

I2C SMBus Control and Status register (I2C1_SMB)

8

R/W

00h

38.3.9/699

4006_7009

I2C Address Register 2 (I2C1_A2)

8

R/W

C2h

38.3.10/
701

4006_700A

I2C SCL Low Timeout Register High (I2C1_SLTH)

8

R/W

00h

38.3.11/
701

4006_700B

I2C SCL Low Timeout Register Low (I2C1_SLTL)

8

R/W

00h

38.3.12/
701

1

0

38.3.1 I2C Address Register 1 (I2Cx_A1)
This register contains the slave address to be used by the I2C module.
Address: Base address + 0h offset
Bit

Read
Write
Reset

7

6

5

4

3

2

0

AD[7:1]
0

0

0

0

0

0

0

0

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Chapter 38 Inter-Integrated Circuit (I2C)

I2Cx_A1 field descriptions
Field
7–1
AD[7:1]

0
Reserved

Description
Address
Contains the primary slave address used by the I2C module when it is addressed as a slave. This field is
used in the 7-bit address scheme and the lower seven bits in the 10-bit address scheme.
This field is reserved.
This read-only field is reserved and always has the value 0.

38.3.2 I2C Frequency Divider register (I2Cx_F)
Address: Base address + 1h offset
Bit

Read
Write
Reset

7

6

5

4

3

MULT
0

2

1

0

0

0

0

ICR
0

0

0

0

I2Cx_F field descriptions
Field
7–6
MULT

Description
The MULT bits define the multiplier factor mul. This factor is used along with the SCL divider to generate
the I2C baud rate.
00
01
10
11

5–0
ICR

mul = 1
mul = 2
mul = 4
Reserved

ClockRate
Prescales the bus clock for bit rate selection. This field and the MULT field determine the I2C baud rate,
the SDA hold time, the SCL start hold time, and the SCL stop hold time. For a list of values corresponding
to each ICR setting, see I2C divider and hold values.
The SCL divider multiplied by multiplier factor (mul) determines the I2C baud rate.
I2C baud rate = bus speed (Hz)/(mul × SCL divider)
The SDA hold time is the delay from the falling edge of SCL (I2C clock) to the changing of SDA (I2C data).
SDA hold time = bus period (s) × mul × SDA hold value
The SCL start hold time is the delay from the falling edge of SDA (I2C data) while SCL is high (start
condition) to the falling edge of SCL (I2C clock).
SCL start hold time = bus period (s) × mul × SCL start hold value
The SCL stop hold time is the delay from the rising edge of SCL (I2C clock) to the rising edge of SDA (I2C
data) while SCL is high (stop condition).
SCL stop hold time = bus period (s) × mul × SCL stop hold value
For example, if the bus speed is 8 MHz, the following table shows the possible hold time values with
different ICR and MULT selections to achieve an I2C baud rate of 100 kbps.
Table continues on the next page...

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Memory map and register descriptions

I2Cx_F field descriptions (continued)
Field

Description
MULT

ICR

2h

Hold times (μs)
SDA

SCL Start

SCL Stop

00h

3.500

3.000

5.500

1h

07h

2.500

4.000

5.250

1h

0Bh

2.250

4.000

5.250

0h

14h

2.125

4.250

5.125

0h

18h

1.125

4.750

5.125

38.3.3 I2C Control Register 1 (I2Cx_C1)
Address: Base address + 2h offset
Bit

Read
Write
Reset

7

6

5

4

3

IICEN

IICIE

MST

TX

TXAK

0

0

0

0

0

2

0
RSTA
0

1

0

WUEN

DMAEN

0

0

I2Cx_C1 field descriptions
Field
7
IICEN

Description
I2C Enable
Enables I2C module operation.
0
1

6
IICIE

I2C Interrupt Enable
Enables I2C interrupt requests.
0
1

5
MST

Disabled
Enabled

Master Mode Select
When the MST bit is changed from a 0 to a 1, a START signal is generated on the bus and master mode
is selected. When this bit changes from a 1 to a 0, a STOP signal is generated and the mode of operation
changes from master to slave.
0
1

4
TX

Disabled
Enabled

Slave mode
Master mode

Transmit Mode Select
Table continues on the next page...

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Chapter 38 Inter-Integrated Circuit (I2C)

I2Cx_C1 field descriptions (continued)
Field

Description
Selects the direction of master and slave transfers. In master mode this bit must be set according to the
type of transfer required. Therefore, for address cycles, this bit is always set. When addressed as a slave
this bit must be set by software according to the SRW bit in the status register.
0
1

3
TXAK

Receive
Transmit

Transmit Acknowledge Enable
Specifies the value driven onto the SDA during data acknowledge cycles for both master and slave
receivers. The value of the FACK bit affects NACK/ACK generation.
NOTE: SCL is held low until TXAK is written.
0
1

An acknowledge signal is sent to the bus on the following receiving byte (if FACK is cleared) or the
current receiving byte (if FACK is set).
No acknowledge signal is sent to the bus on the following receiving data byte (if FACK is cleared) or
the current receiving data byte (if FACK is set).

2
RSTA

Repeat START

1
WUEN

Wakeup Enable

Writing a one to this bit generates a repeated START condition provided it is the current master. This bit
will always be read as zero. Attempting a repeat at the wrong time results in loss of arbitration.

The I2C module can wake the MCU from low power mode with no peripheral bus running when slave
address matching occurs.
0
1

0
DMAEN

Normal operation. No interrupt generated when address matching in low power mode.
Enables the wakeup function in low power mode.

DMA Enable
The DMAEN bit enables or disables the DMA function.
0
1

All DMA signalling disabled.
DMA transfer is enabled and the following conditions trigger the DMA request:
• While FACK = 0, a data byte is received, either address or data is transmitted. (ACK/NACK
automatic)
• While FACK = 0, the first byte received matches the A1 register or is general call address.
If any address matching occurs, IAAS and TCF are set. If the direction of transfer is known from
master to slave, then it is not required to check the SRW. With this assumption, DMA can also be
used in this case. In other cases, if the master reads data from the slave, then it is required to rewrite
the C1 register operation. With this assumption, DMA cannot be used.
When FACK = 1, an address or a data byte is transmitted.

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38.3.4 I2C Status register (I2Cx_S)
Address: Base address + 3h offset
Bit

Read

7

6

TCF

IAAS

Write
Reset

1

5

4

BUSY

ARBL

3

RAM

w1c

0

0

0

0

2

1

0

SRW

IICIF

RXAK

w1c
0

0

0

I2Cx_S field descriptions
Field
7
TCF

Description
Transfer Complete Flag
This bit sets on the completion of a byte and acknowledge bit transfer. This bit is valid only during or
immediately following a transfer to or from the I2C module. The TCF bit is cleared by reading the I2C data
register in receive mode or by writing to the I2C data register in transmit mode.
0
1

6
IAAS

Transfer in progress
Transfer complete

Addressed As A Slave
This bit is set by one of the following conditions:
• The calling address matches the programmed slave primary address in the A1 register or range
address in the RA register (which must be set to a nonzero value).
• GCAEN is set and a general call is received.
• SIICAEN is set and the calling address matches the second programmed slave address.
• ALERTEN is set and an SMBus alert response address is received
• RMEN is set and an address is received that is within the range between the values of the A1 and
RA registers.
This bit sets before the ACK bit. The CPU must check the SRW bit and set TX/RX accordingly. Writing the
C1 register with any value clears this bit.
0
1

5
BUSY

Bus Busy
Indicates the status of the bus regardless of slave or master mode. This bit is set when a START signal is
detected and cleared when a STOP signal is detected.
0
1

4
ARBL

Bus is idle
Bus is busy

Arbitration Lost
This bit is set by hardware when the arbitration procedure is lost. The ARBL bit must be cleared by
software, by writing a one to it.
0
1

3
RAM

Not addressed
Addressed as a slave

Standard bus operation.
Loss of arbitration.

Range Address Match
This bit is set to 1 by any of the following conditions:
Table continues on the next page...

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Chapter 38 Inter-Integrated Circuit (I2C)

I2Cx_S field descriptions (continued)
Field

Description
• Any nonzero calling address is received that matches the address in the RA register.
• The RMEN bit is set and the calling address is within the range of values of the A1 and RA registers.
NOTE: For the RAM bit to be set to 1 correctly, C1[IICIE] must be set to 1.
Writing the C1 register with any value clears this bit to 0.
0
1

2
SRW

Slave Read/Write
When addressed as a slave, SRW indicates the value of the R/W command bit of the calling address sent
to the master.
0
1

1
IICIF

Not addressed
Addressed as a slave

Slave receive, master writing to slave
Slave transmit, master reading from slave

Interrupt Flag
This bit sets when an interrupt is pending. This bit must be cleared by software by writing a 1 to it, such as
in the interrupt routine. One of the following events can set this bit:
• One byte transfer, including ACK/NACK bit, completes if FACK is 0. An ACK or NACK is sent on the
bus by writing 0 or 1 to TXAK after this bit is set in receive mode.
• One byte transfer, excluding ACK/NACK bit, completes if FACK is 1.
• Match of slave address to calling address including primary slave address, range slave address,
alert response address, second slave address, or general call address.
• Arbitration lost
• In SMBus mode, any timeouts except SCL and SDA high timeouts
• I2C bus stop detection if the STOPIE bit in the Input Glitch Filter register is 1
NOTE:

0
1
0
RXAK

To clear the I2C bus stop detection interrupt: In the interrupt service routine,
first clear the STOPF bit in the Input Glitch Filter register by writing 1 to it, and
then clear the IICIF bit. If this sequence is reversed, the IICIF bit is asserted
again.

No interrupt pending
Interrupt pending

Receive Acknowledge
0
1

Acknowledge signal was received after the completion of one byte of data transmission on the bus
No acknowledge signal detected

38.3.5 I2C Data I/O register (I2Cx_D)
Address: Base address + 4h offset
Bit

Read
Write
Reset

7

6

5

4

3

2

1

0

0

0

0

0

DATA
0

0

0

0

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I2Cx_D field descriptions
Field
7–0
DATA

Description
Data
In master transmit mode, when data is written to this register, a data transfer is initiated. The most
significant bit is sent first. In master receive mode, reading this register initiates receiving of the next byte
of data.
NOTE: When making the transition out of master receive mode, switch the I2C mode before reading the
Data register to prevent an inadvertent initiation of a master receive data transfer.
In slave mode, the same functions are available after an address match occurs.
The C1[TX] bit must correctly reflect the desired direction of transfer in master and slave modes for the
transmission to begin. For example, if the I2C module is configured for master transmit but a master
receive is desired, reading the Data register does not initiate the receive.
Reading the Data register returns the last byte received while the I2C module is configured in master
receive or slave receive mode. The Data register does not reflect every byte that is transmitted on the I2C
bus, and neither can software verify that a byte has been written to the Data register correctly by reading it
back.
In master transmit mode, the first byte of data written to the Data register following assertion of MST (start
bit) or assertion of RSTA (repeated start bit) is used for the address transfer and must consist of the
calling address (in bits 7-1) concatenated with the required R/W bit (in position bit 0).

38.3.6 I2C Control Register 2 (I2Cx_C2)
Address: Base address + 5h offset
Bit

Read
Write
Reset

7

6

5

4

3

GCAEN

ADEXT

HDRS

SBRC

RMEN

0

0

0

0

0

2

1

0

AD[10:8]
0

0

0

I2Cx_C2 field descriptions
Field
7
GCAEN

Description
General Call Address Enable
Enables general call address.
0
1

6
ADEXT

Address Extension
Controls the number of bits used for the slave address.
0
1

5
HDRS

Disabled
Enabled

7-bit address scheme
10-bit address scheme

High Drive Select
Controls the drive capability of the I2C pads.
Table continues on the next page...

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Chapter 38 Inter-Integrated Circuit (I2C)

I2Cx_C2 field descriptions (continued)
Field

Description
0
1

4
SBRC

Slave Baud Rate Control
Enables independent slave mode baud rate at maximum frequency, which forces clock stretching on SCL
in very fast I2C modes. To a slave, an example of a "very fast" mode is when the master transfers at 40
kbps but the slave can capture the master's data at only 10 kbps.
0
1

3
RMEN

The slave baud rate follows the master baud rate and clock stretching may occur
Slave baud rate is independent of the master baud rate

Range Address Matching Enable
This bit controls slave address matching for addresses between the values of the A1 and RA registers.
When this bit is set, a slave address match occurs for any address greater than the value of the A1
register and less than or equal to the value of the RA register.
0
1

2–0
AD[10:8]

Normal drive mode
High drive mode

Range mode disabled. No address match occurs for an address within the range of values of the A1
and RA registers.
Range mode enabled. Address matching occurs when a slave receives an address within the range of
values of the A1 and RA registers.

Slave Address
Contains the upper three bits of the slave address in the 10-bit address scheme. This field is valid only
while the ADEXT bit is set.

38.3.7 I2C Programmable Input Glitch Filter register (I2Cx_FLT)
Address: Base address + 6h offset
Bit

Read
Write
Reset

7

6

STOPF

SHEN

w1c

0

0

5

4

3

STOPIE
0

2

1

0

0

0

FLT
0

0

0

I2Cx_FLT field descriptions
Field
7
SHEN

Description
Stop Hold Enable
Set this bit to hold off entry to stop mode when any data transmission or reception is occurring.
The following scenario explains the holdoff functionality:
1. The I2C module is configured for a basic transfer, and the SHEN bit is set to 1.
2. A transfer begins.
3. The MCU signals the I2C module to enter stop mode.
4. The byte currently being transferred, including both address and data, completes its transfer.
5. The I2C slave or master acknowledges that the in-transfer byte completed its transfer and
acknowledges the request to enter stop mode.
6. After receiving the I2C module's acknowledgment of the request to enter stop mode, the MCU
determines whether to shut off the I2C module's clock.
Table continues on the next page...

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I2Cx_FLT field descriptions (continued)
Field

Description
If the SHEN bit is set to 1 and the I2C module is in an idle or disabled state when the MCU signals to enter
stop mode, the module immediately acknowledges the request to enter stop mode.
If SHEN is cleared to 0 and the overall data transmission or reception that was suspended by stop mode
entry was incomplete: To resume the overall transmission or reception after the MCU exits stop mode,
software must reinitialize the transfer by resending the address of the slave.
If the I2C Control Register 1's IICIE bit was set to 1 before the MCU entered stop mode, system software
will receive the interrupt triggered by the I2C Status Register's TCF bit after the MCU wakes from the stop
mode.
0
1

6
STOPF

I2C Bus Stop Detect Flag
Hardware sets this bit when the I2C bus's stop status is detected. The STOPF bit must be cleared by
writing 1 to it.
0
1

5
STOPIE

Stop holdoff is disabled. The MCU's entry to stop mode is not gated.
Stop holdoff is enabled.

No stop happens on I2C bus
Stop detected on I2C bus

I2C Bus Stop Interrupt Enable
This bit enables the interrupt for I2C bus stop detection.
NOTE: To clear the I2C bus stop detection interrupt: In the interrupt service routine, first clear the STOPF
bit by writing 1 to it, and then clear the IICIF bit in the status register. If this sequence is reversed,
the IICIF bit is asserted again.
0
1

4–0
FLT

Stop detection interrupt is disabled
Stop detection interrupt is enabled

I2C Programmable Filter Factor
Controls the width of the glitch, in terms of bus clock cycles, that the filter must absorb. For any glitch
whose size is less than or equal to this width setting, the filter does not allow the glitch to pass.
00h
01-1Fh

No filter/bypass
Filter glitches up to width of n bus clock cycles, where n=1-31d

38.3.8 I2C Range Address register (I2Cx_RA)
Address: Base address + 7h offset
Bit

Read
Write
Reset

7

6

5

4

3

2

1

0

RAD
0

0

0

0

0

0

0

0

0

I2Cx_RA field descriptions
Field
7–1
RAD

Description
Range Slave Address
Table continues on the next page...

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Chapter 38 Inter-Integrated Circuit (I2C)

I2Cx_RA field descriptions (continued)
Field

Description
This field contains the slave address to be used by the I2C module. The field is used in the 7-bit address
scheme. Any nonzero write enables this register. This register's use is similar to that of the A1 register, but
in addition this register can be considered a maximum boundary in range matching mode.

0
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

38.3.9 I2C SMBus Control and Status register (I2Cx_SMB)
NOTE
When the SCL and SDA signals are held high for a length of
time greater than the high timeout period, the SHTF1 flag sets.
Before reaching this threshold, while the system is detecting
how long these signals are being held high, a master assumes
that the bus is free. However, the SHTF1 bit rises in the bus
transmission process with the idle bus state.
NOTE
When the TCKSEL bit is set, there is no need to monitor the
SHTF1 bit because the bus speed is too high to match the
protocol of SMBus.
Address: Base address + 8h offset
Bit

Read
Write
Reset

7

6

5

4

FACK

ALERTEN

SIICAEN

TCKSEL

0

0

0

0

3

2

1

SLTF

SHTF1

SHTF2

w1c
0

w1c
0

0

0

SHTF2IE
0

I2Cx_SMB field descriptions
Field
7
FACK

Description
Fast NACK/ACK Enable
For SMBus packet error checking, the CPU must be able to issue an ACK or NACK according to the result
of receiving data byte.
0
1

6
ALERTEN

An ACK or NACK is sent on the following receiving data byte
Writing 0 to TXAK after receiving a data byte generates an ACK. Writing 1 to TXAK after receiving a
data byte generates a NACK.

SMBus Alert Response Address Enable
Enables or disables SMBus alert response address matching.
NOTE: After the host responds to a device that used the alert response address, you must use software
to put the device's address on the bus. The alert protocol is described in the SMBus specification.
Table continues on the next page...

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Memory map and register descriptions

I2Cx_SMB field descriptions (continued)
Field

Description
0
1

5
SIICAEN

Second I2C Address Enable
Enables or disables SMBus device default address.
0
1

4
TCKSEL

I2C address register 2 matching is disabled
I2C address register 2 matching is enabled

Timeout Counter Clock Select
Selects the clock source of the timeout counter.
0
1

3
SLTF

SMBus alert response address matching is disabled
SMBus alert response address matching is enabled

Timeout counter counts at the frequency of the bus clock / 64
Timeout counter counts at the frequency of the bus clock

SCL Low Timeout Flag
This bit is set when the SLT register (consisting of the SLTH and SLTL registers) is loaded with a non-zero
value (LoValue) and an SCL low timeout occurs. Software clears this bit by writing a logic 1 to it.
NOTE: The low timeout function is disabled when the SLT register's value is zero.
0
1

2
SHTF1

SCL High Timeout Flag 1
This read-only bit sets when SCL and SDA are held high more than clock × LoValue / 512, which indicates
the bus is free. This bit is cleared automatically.
0
1

1
SHTF2

No SCL high and SDA high timeout occurs
SCL high and SDA high timeout occurs

SCL High Timeout Flag 2
This bit sets when SCL is held high and SDA is held low more than clock × LoValue/512. Software clears
this bit by writing a 1 to it.
0
1

0
SHTF2IE

No low timeout occurs
Low timeout occurs

No SCL high and SDA low timeout occurs
SCL high and SDA low timeout occurs

SHTF2 Interrupt Enable
Enables SCL high and SDA low timeout interrupt.
0
1

SHTF2 interrupt is disabled
SHTF2 interrupt is enabled

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Chapter 38 Inter-Integrated Circuit (I2C)

38.3.10 I2C Address Register 2 (I2Cx_A2)
Address: Base address + 9h offset
Bit

Read
Write
Reset

7

6

5

4

3

2

1

SAD
1

1

0

0

0

0

0

0

1

0

I2Cx_A2 field descriptions
Field
7–1
SAD

0
Reserved

Description
SMBus Address
Contains the slave address used by the SMBus. This field is used on the device default address or other
related addresses.
This field is reserved.
This read-only field is reserved and always has the value 0.

38.3.11 I2C SCL Low Timeout Register High (I2Cx_SLTH)
Address: Base address + Ah offset
Bit

Read
Write
Reset

7

6

5

4

3

2

1

0

0

0

0

0

SSLT[15:8]
0

0

0

0

I2Cx_SLTH field descriptions
Field
7–0
SSLT[15:8]

Description
Most significant byte of SCL low timeout value that determines the timeout period of SCL low.

38.3.12 I2C SCL Low Timeout Register Low (I2Cx_SLTL)
Address: Base address + Bh offset
Bit

Read
Write
Reset

7

6

5

4

3

2

1

0

0

0

0

0

SSLT[7:0]
0

0

0

0

I2Cx_SLTL field descriptions
Field
7–0
SSLT[7:0]

Description
Least significant byte of SCL low timeout value that determines the timeout period of SCL low.

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38.4 Functional description
This section provides a comprehensive functional description of the I2C module.

38.4.1 I2C protocol
The I2C bus system uses a serial data line (SDA) and a serial clock line (SCL) for data
transfers. All devices connected to it must have open drain or open collector outputs. A
logic AND function is exercised on both lines with external pull-up resistors. The value
of these resistors depends on the system.
Normally, a standard instance of communication is composed of four parts:
1.
2.
3.
4.

START signal
Slave address transmission
Data transfer
STOP signal

The STOP signal should not be confused with the CPU STOP instruction. The following
figure illustrates I2C bus system communication.
M SB
SCL

SDA

1

SDA

Start
Signal

3

4

5

6

7

8

9

A D 7 A D 6 A D 5 A D 4 A D 3 A D 2 A D 1 R /W
C a llin g A d d re s s

Start Signal

SCL

M SB

LSB
2

3

4

5

6

4

5

6

7

8

D7

D6

D5

D4

D3

D2

D1

D0

7

8

1

R e a d / Ack
W rite Bit

XX

9

No Stop
Ack Signal
Bit

M SB
9

A D 7 A D 6 A D 5 A D 4 A D 3 A D 2 A D 1 R /W

C a llin g A d d re s s

3

D a ta B y te

LSB
2

2

R e a d / Ack
W rite Bit

M SB
1

XXX

LSB

1

LSB
2

3

4

5

6

7

8

9

A D 7 A D 6 A D 5 A D 4 A D 3 A D 2 A D 1 R /W
Repeated
Start
Signal

N e w C a llin g A d d re s s

Read/
W rite

No Stop
Ack Signal
Bit

Figure 38-38. I2C bus transmission signals

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Chapter 38 Inter-Integrated Circuit (I2C)

38.4.1.1 START signal
The bus is free when no master device is engaging the bus (both SCL and SDA are high).
When the bus is free, a master may initiate communication by sending a START signal.
A START signal is defined as a high-to-low transition of SDA while SCL is high. This
signal denotes the beginning of a new data transfer—each data transfer might contain
several bytes of data—and brings all slaves out of their idle states.

38.4.1.2 Slave address transmission
Immediately after the START signal, the first byte of a data transfer is the slave address
transmitted by the master. This address is a 7-bit calling address followed by an R/W bit.
The R/W bit tells the slave the desired direction of data transfer.
• 1 = Read transfer: The slave transmits data to the master
• 0 = Write transfer: The master transmits data to the slave
Only the slave with a calling address that matches the one transmitted by the master
responds by sending an acknowledge bit. The slave sends the acknowledge bit by pulling
SDA low at the ninth clock.
No two slaves in the system can have the same address. If the I2C module is the master, it
must not transmit an address that is equal to its own slave address. The I2C module
cannot be master and slave at the same time. However, if arbitration is lost during an
address cycle, the I2C module reverts to slave mode and operates correctly even if it is
being addressed by another master.

38.4.1.3 Data transfers
When successful slave addressing is achieved, data transfer can proceed on a byte-bybyte basis in the direction specified by the R/W bit sent by the calling master.
All transfers that follow an address cycle are referred to as data transfers, even if they
carry subaddress information for the slave device.
Each data byte is 8 bits long. Data may be changed only while SCL is low. Data must be
held stable while SCL is high. There is one clock pulse on SCL for each data bit, and the
MSB is transferred first. Each data byte is followed by a ninth (acknowledge) bit, which
is signaled from the receiving device by pulling SDA low at the ninth clock. In summary,
one complete data transfer needs nine clock pulses.

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If the slave receiver does not acknowledge the master in the ninth bit, the slave must
leave SDA high. The master interprets the failed acknowledgement as an unsuccessful
data transfer.
If the master receiver does not acknowledge the slave transmitter after a data byte
transmission, the slave interprets it as an end to data transfer and releases the SDA line.
In the case of a failed acknowledgement by either the slave or master, the data transfer is
aborted and the master does one of two things:
• Relinquishes the bus by generating a STOP signal.
• Commences a new call by generating a repeated START signal.

38.4.1.4 STOP signal
The master can terminate the communication by generating a STOP signal to free the
bus. A STOP signal is defined as a low-to-high transition of SDA while SCL is asserted.
The master can generate a STOP signal even if the slave has generated an
acknowledgement, at which point the slave must release the bus.

38.4.1.5 Repeated START signal
The master may generate a START signal followed by a calling command without
generating a STOP signal first. This action is called a repeated START. The master uses
a repeated START to communicate with another slave or with the same slave in a
different mode (transmit/receive mode) without releasing the bus.

38.4.1.6 Arbitration procedure
The I2C bus is a true multimaster bus that allows more than one master to be connected
on it.
If two or more masters try to control the bus at the same time, a clock synchronization
procedure determines the bus clock. The bus clock's low period is equal to the longest
clock low period, and the high period is equal to the shortest one among the masters.
The relative priority of the contending masters is determined by a data arbitration
procedure. A bus master loses arbitration if it transmits logic level 1 while another master
transmits logic level 0. The losing masters immediately switch to slave receive mode and
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Chapter 38 Inter-Integrated Circuit (I2C)

stop driving SDA output. In this case, the transition from master to slave mode does not
generate a STOP condition. Meanwhile, hardware sets a status bit to indicate the loss of
arbitration.

38.4.1.7 Clock synchronization
Because wire AND logic is performed on SCL, a high-to-low transition on SCL affects
all devices connected on the bus. The devices start counting their low period and, after a
device's clock has gone low, that device holds SCL low until the clock reaches its high
state. However, the change of low to high in this device clock might not change the state
of SCL if another device clock is still within its low period. Therefore, the synchronized
clock SCL is held low by the device with the longest low period. Devices with shorter
low periods enter a high wait state during this time; see the following diagram. When all
applicable devices have counted off their low period, the synchronized clock SCL is
released and pulled high. Afterward there is no difference between the device clocks and
the state of SCL, and all devices start counting their high periods. The first device to
complete its high period pulls SCL low again.
D e la y

S ta rt C o u n tin g H ig h P e rio d

SCL1

SCL2

SCL

In te rn a l C o u n te r R e s e t

Figure 38-39. I2C clock synchronization

38.4.1.8 Handshaking
The clock synchronization mechanism can be used as a handshake in data transfers. A
slave device may hold SCL low after completing a single byte transfer (9 bits). In this
case, it halts the bus clock and forces the master clock into wait states until the slave
releases SCL.

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38.4.1.9 Clock stretching
The clock synchronization mechanism can be used by slaves to slow down the bit rate of
a transfer. After the master drives SCL low, a slave can drive SCL low for the required
period and then release it. If the slave's SCL low period is greater than the master's SCL
low period, the resulting SCL bus signal's low period is stretched. In other words, the
SCL bus signal's low period is increased to be the same length as the slave's SCL low
period.

38.4.1.10 I2C divider and hold values
NOTE
For some cases on some devices, the SCL divider value may
vary by +/-2 or +/-4 when ICR’s value ranges from 00h to 0Fh.
These potentially varying SCL divider values are highlighted in
the following table. For the actual SCL divider values for your
device, see the chip-specific details about the I2C module.
Table 38-41. I2C divider and hold values
ICR

SCL
divider

SDA hold
value

SCL hold
(start)
value

SCL hold
(stop)
value

SCL
divider
(clocks)

SDA hold
(clocks)

SCL hold
(start)
value

SCL hold
(stop)
value

00

20

7

6

11

20

160

17

78

81

01

22

7

7

12

21

192

17

94

97

02

24

8

8

13

22

224

33

110

113

03

26

8

9

14

23

256

33

126

129

04

28

9

10

15

24

288

49

142

145

05
06

30

9

11

16

25

320

49

158

161

34

10

13

18

26

384

65

190

193

07

40

10

16

21

27

480

65

238

241

08

28

7

10

15

28

320

33

158

161

09

32

7

12

17

29

384

33

190

193

0A

36

9

14

19

2A

448

65

222

225

0B

40

9

16

21

2B

512

65

254

257

0C

44

11

18

23

2C

576

97

286

289

0D

48

11

20

25

2D

640

97

318

321

0E

56

13

24

29

2E

768

129

382

385

0F

68

13

30

35

2F

960

129

478

481

10

48

9

18

25

30

640

65

318

321

11

56

9

22

29

31

768

65

382

385

12

64

13

26

33

32

896

129

446

449

13

72

13

30

37

33

1024

129

510

513

(hex)

ICR
(hex)

Table continues on the next page...

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Chapter 38 Inter-Integrated Circuit (I2C)

Table 38-41. I2C divider and hold values (continued)
ICR

SCL
divider

SDA hold
value

SCL hold
(start)
value

SCL hold
(stop)
value

SCL
divider
(clocks)

SDA hold
(clocks)

SCL hold
(start)
value

SCL hold
(stop)
value

14

80

17

34

41

34

1152

193

574

577

15

88

17

38

45

35

1280

193

638

641

16

104

21

46

53

36

1536

257

766

769

17

128

18

80

21

58

65

37

1920

257

958

961

9

38

41

38

1280

129

638

641

19

96

9

46

49

39

1536

129

766

769

1A

112

17

54

57

3A

1792

257

894

897

1B

128

17

62

65

3B

2048

257

1022

1025

1C

144

25

70

73

3C

2304

385

1150

1153

1D

160

25

78

81

3D

2560

385

1278

1281

1E

192

33

94

97

3E

3072

513

1534

1537

1F

240

33

118

121

3F

3840

513

1918

1921

(hex)

ICR
(hex)

38.4.2 10-bit address
For 10-bit addressing, 0x11110 is used for the first 5 bits of the first address byte.
Various combinations of read/write formats are possible within a transfer that includes
10-bit addressing.

38.4.2.1 Master-transmitter addresses a slave-receiver
The transfer direction is not changed. When a 10-bit address follows a START condition,
each slave compares the first 7 bits of the first byte of the slave address (11110XX) with
its own address and tests whether the eighth bit (R/W direction bit) is 0. It is possible that
more than one device finds a match and generates an acknowledge (A1). Each slave that
finds a match compares the 8 bits of the second byte of the slave address with its own
address, but only one slave finds a match and generates an acknowledge (A2). The
matching slave remains addressed by the master until it receives a STOP condition (P) or
a repeated START condition (Sr) followed by a different slave address.

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Table 38-42. Master-transmitter addresses slave-receiver with a 10-bit
address
S

Slave
address
first 7 bits
11110 +
AD10 +
AD9

R/W
0

A1

Slave
address
second
byte
AD[8:1]

A2

Data

A

...

Data

A/A

P

After the master-transmitter has sent the first byte of the 10-bit address, the slave-receiver
sees an I2C interrupt. User software must ensure that for this interrupt, the contents of the
Data register are ignored and not treated as valid data.

38.4.2.2 Master-receiver addresses a slave-transmitter
The transfer direction is changed after the second R/W bit. Up to and including
acknowledge bit A2, the procedure is the same as that described for a master-transmitter
addressing a slave-receiver. After the repeated START condition (Sr), a matching slave
remembers that it was addressed before. This slave then checks whether the first seven
bits of the first byte of the slave address following Sr are the same as they were after the
START condition (S), and it tests whether the eighth (R/W) bit is 1. If there is a match,
the slave considers that it has been addressed as a transmitter and generates acknowledge
A3. The slave-transmitter remains addressed until it receives a STOP condition (P) or a
repeated START condition (Sr) followed by a different slave address.
After a repeated START condition (Sr), all other slave devices also compare the first
seven bits of the first byte of the slave address with their own addresses and test the
eighth (R/W) bit. However, none of them are addressed because R/W = 1 (for 10-bit
devices), or the 11110XX slave address (for 7-bit devices) does not match.
Table 38-43. Master-receiver addresses a slave-transmitter with a 10-bit
address
S

Slave
address
first 7
bits
11110 +
AD10 +
AD9

R/W
0

A1

Slave
address
second
byte
AD[8:1]

A2

Sr

Slave
address
first 7
bits
11110 +
AD10 +
AD9

R/W
1

A3

Data

A

...

Data

A

P

After the master-receiver has sent the first byte of the 10-bit address, the slave-transmitter
sees an I2C interrupt. User software must ensure that for this interrupt, the contents of the
Data register are ignored and not treated as valid data.
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Chapter 38 Inter-Integrated Circuit (I2C)

38.4.3 Address matching
All received addresses can be requested in 7-bit or 10-bit address format.
• AD[7:1] in Address Register 1, which contains the I2C primary slave address, always
participates in the address matching process. It provides a 7-bit address.
• If the ADEXT bit is set, AD[10:8] in Control Register 2 participates in the address
matching process. It extends the I2C primary slave address to a 10-bit address.
Additional conditions that affect address matching include:
• If the GCAEN bit is set, general call participates the address matching process.
• If the ALERTEN bit is set, alert response participates the address matching process.
• If the SIICAEN bit is set, Address Register 2 participates in the address matching
process.
• If the Range Address register is programmed to a nonzero value, the range address
itself participates in the address matching process.
• If the RMEN bit is set, any address within the range of values of Address Register 1
and the Range Address register participates in the address matching process. The
Range Address register must be programmed to a value greater than the value of
Address Register 1.
When the I2C module responds to one of these addresses, it acts as a slave-receiver and
the IAAS bit is set after the address cycle. Software must read the Data register after the
first byte transfer to determine that the address is matched.

38.4.4 System management bus specification
SMBus provides a control bus for system and power management related tasks. A system
can use SMBus to pass messages to and from devices instead of tripping individual
control lines. Removing the individual control lines reduces pin count. Accepting
messages ensures future expandability. With the system management bus, a device can
provide manufacturer information, tell the system what its model/part number is, save its
state for a suspend event, report different types of errors, accept control parameters, and
return its status.

38.4.4.1 Timeouts
The TTIMEOUT,MIN parameter allows a master or slave to conclude that a defective device
is holding the clock low indefinitely or a master is intentionally trying to drive devices
off the bus. The slave device must release the bus (stop driving the bus and let SCL and
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Functional description

SDA float high) when it detects any single clock held low longer than TTIMEOUT,MIN.
Devices that have detected this condition must reset their communication and be able to
receive a new START condition within the timeframe of TTIMEOUT,MAX.
SMBus defines a clock low timeout, TTIMEOUT, of 35 ms, specifies TLOW:SEXT as the
cumulative clock low extend time for a slave device, and specifies TLOW:MEXT as the
cumulative clock low extend time for a master device.
38.4.4.1.1

SCL low timeout

If the SCL line is held low by a slave device on the bus, no further communication is
possible. Furthermore, the master cannot force the SCL line high to correct the error
condition. To solve this problem, the SMBus protocol specifies that devices participating
in a transfer must detect any clock cycle held low longer than a timeout value condition.
Devices that have detected the timeout condition must reset the communication. When
the I2C module is an active master, if it detects that SMBCLK low has exceeded the
value of TTIMEOUT,MIN, it must generate a stop condition within or after the current data
byte in the transfer process. When the I2C module is a slave, if it detects the
TTIMEOUT,MIN condition, it resets its communication and is then able to receive a new
START condition.
38.4.4.1.2

SCL high timeout

When the I2C module has determined that the SMBCLK and SMBDAT signals have
been high for at least THIGH:MAX, it assumes that the bus is idle.
A HIGH timeout occurs after a START condition appears on the bus but before a STOP
condition appears on the bus. Any master detecting this scenario can assume the bus is
free when either of the following occurs:
• SHTF1 rises.
• The BUSY bit is high and SHTF1 is high.
When the SMBDAT signal is low and the SMBCLK signal is high for a period of time,
another kind of timeout occurs. The time period must be defined in software. SHTF2 is
used as the flag when the time limit is reached. This flag is also an interrupt resource, so
it triggers IICIF.

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Chapter 38 Inter-Integrated Circuit (I2C)

38.4.4.1.3

CSMBCLK TIMEOUT MEXT and CSMBCLK TIMEOUT SEXT

The following figure illustrates the definition of the timeout intervals TLOW:SEXT and
TLOW:MEXT. When in master mode, the I2C module must not cumulatively extend its
clock cycles for a period greater than TLOW:MEXT within a byte, where each byte is
defined as START-to-ACK, ACK-to-ACK, or ACK-to-STOP. When CSMBCLK
TIMEOUT MEXT occurs, SMBus MEXT rises and also triggers the SLTF.
Stop

T LOW:SEXT

Start

T LOW:MEXT

ClkAck

T LOW:MEXT

ClkAck

T LOW:MEXT

SCL

SDA

Figure 38-40. Timeout measurement intervals

A master is allowed to abort the transaction in progress to any slave that violates the
TLOW:SEXT or TTIMEOUT,MIN specifications. To abort the transaction, the master issues a
STOP condition at the conclusion of the byte transfer in progress. When a slave, the I2C
module must not cumulatively extend its clock cycles for a period greater than
TLOW:SEXT during any message from the initial START to the STOP. When CSMBCLK
TIMEOUT SEXT occurs, SEXT rises and also triggers SLTF.
NOTE
CSMBCLK TIMEOUT SEXT and CSMBCLK TIMEOUT
MEXT are optional functions that are implemented in the
second step.

38.4.4.2 FAST ACK and NACK
To improve reliability and communication robustness, implementation of packet error
checking (PEC) by SMBus devices is optional for SMBus devices but required for
devices participating in and only during the address resolution protocol (ARP) process.
The PEC is a CRC-8 error checking byte, calculated on all the message bytes. The PEC is
appended to the message by the device that supplied the last data byte. If the PEC is
present but not correct, a NACK is issued by the receiver. Otherwise an ACK is issued.
To calculate the CRC-8 by software, this module can hold the SCL line low after

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Functional description

receiving the eighth SCL (8th bit) if this byte is a data byte. So software can determine
whether an ACK or NACK should be sent to the bus by setting or clearing the TXAK bit
if the FACK (fast ACK/NACK enable) bit is enabled.
SMBus requires a device always to acknowledge its own address, as a mechanism to
detect the presence of a removable device (such as a battery or docking station) on the
bus. In addition to indicating a slave device busy condition, SMBus uses the NACK
mechanism to indicate the reception of an invalid command or invalid data. Because such
a condition may occur on the last byte of the transfer, SMBus devices are required to
have the ability to generate the not acknowledge after the transfer of each byte and before
the completion of the transaction. This requirement is important because SMBus does not
provide any other resend signaling. This difference in the use of the NACK signaling has
implications on the specific implementation of the SMBus port, especially in devices that
handle critical system data such as the SMBus host and the SBS components.
NOTE
In the last byte of master receive slave transmit mode, the
master must send a NACK to the bus, so FACK must be
switched off before the last byte transmits.

38.4.5 Resets
The I2C module is disabled after a reset. The I2C module cannot cause a core reset.

38.4.6 Interrupts
The I2C module generates an interrupt when any of the events in the following table
occur, provided that the IICIE bit is set. The interrupt is driven by the IICIF bit (of the
I2C Status Register) and masked with the IICIE bit (of the I2C Control Register 1). The
IICIF bit must be cleared (by software) by writing 1 to it in the interrupt routine. The
SMBus timeouts interrupt is driven by SLTF and masked with the IICIE bit. The SLTF
bit must be cleared by software by writing 1 to it in the interrupt routine. You can
determine the interrupt type by reading the Status Register.
NOTE
In master receive mode, the FACK bit must be set to zero
before the last byte transfer.

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Chapter 38 Inter-Integrated Circuit (I2C)

Table 38-44. Interrupt summary
Interrupt source

Status

Flag

Local enable

Complete 1-byte transfer

TCF

IICIF

IICIE

Match of received calling address

IAAS

IICIF

IICIE

Arbitration lost

ARBL

IICIF

IICIE

STOPF

IICIF

IICIE & STOPIE

SMBus SCL low timeout

SLTF

IICIF

IICIE

SMBus SCL high SDA low timeout

SHTF2

IICIF

IICIE & SHTF2IE

Wakeup from stop or wait mode

IAAS

IICIF

IICIE & WUEN

I2C

bus stop detection

38.4.6.1 Byte transfer interrupt
The Transfer Complete Flag (TCF) bit is set at the falling edge of the ninth clock to
indicate the completion of a byte and acknowledgement transfer. When FACK is enabled,
TCF is then set at the falling edge of eighth clock to indicate the completion of byte.

38.4.6.2 Address detect interrupt
When the calling address matches the programmed slave address (I2C Address Register)
or when the GCAEN bit is set and a general call is received, the IAAS bit in the Status
Register is set. The CPU is interrupted, provided the IICIE bit is set. The CPU must
check the SRW bit and set its Tx mode accordingly.

38.4.6.3 Stop Detect Interrupt
When the stop status is detected on the I2C bus, the STOPF bit is set to 1. The CPU is
interrupted, provided the IICIE and STOPIE bits are both set to 1.

38.4.6.4 Exit from low-power/stop modes
The slave receive input detect circuit and address matching feature are still active on low
power modes (wait and stop). An asynchronous input matching slave address or general
call address brings the CPU out of low power/stop mode if the interrupt is not masked.
Therefore, TCF and IAAS both can trigger this interrupt.

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Functional description

38.4.6.5 Arbitration lost interrupt
The I2C is a true multimaster bus that allows more than one master to be connected on it.
If two or more masters try to control the bus at the same time, the relative priority of the
contending masters is determined by a data arbitration procedure. The I2C module asserts
the arbitration-lost interrupt when it loses the data arbitration process and the ARBL bit
in the Status Register is set.
Arbitration is lost in the following circumstances:
1. SDA is sampled as low when the master drives high during an address or data
transmit cycle.
2. SDA is sampled as low when the master drives high during the acknowledge bit of a
data receive cycle.
3. A START cycle is attempted when the bus is busy.
4. A repeated START cycle is requested in slave mode.
5. A STOP condition is detected when the master did not request it.
The ARBL bit must be cleared (by software) by writing 1 to it.

38.4.6.6 Timeout interrupt in SMBus
When the IICIE bit is set, the I2C module asserts a timeout interrupt (outputs SLTF and
SHTF2) upon detection of any of the mentioned timeout conditions, with one exception.
The SCL high and SDA high TIMEOUT mechanism must not be used to influence the
timeout interrupt output, because this timeout indicates an idle condition on the bus.
SHTF1 rises when it matches the SCL high and SDA high TIMEOUT and falls
automatically just to indicate the bus status. The SHTF2's timeout period is the same as
that of SHTF1, which is short compared to that of SLTF, so another control bit,
SHTF2IE, is added to enable or disable it.

38.4.7 Programmable input glitch filter
An I2C glitch filter has been added outside legacy I2C modules but within the I2C
package. This filter can absorb glitches on the I2C clock and data lines for the I2C
module. The width of the glitch to absorb can be specified in terms of the number of
(half) bus clock cycles. A single Programmable Input Glitch Filter control register is
provided. Effectively, any down-up-down or up-down-up transition on the data line that
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Chapter 38 Inter-Integrated Circuit (I2C)

occurs within the number of clock cycles programmed in this register is ignored by the
I2C module. The programmer must specify the size of the glitch (in terms of bus clock
cycles) for the filter to absorb and not pass.
Noise
suppress
circuits

SCL, SDA
internal signals

SCL, SDA
external signals
DFF

DFF

DFF

DFF

Figure 38-41. Programmable input glitch filter diagram

38.4.8 Address matching wakeup
When a primary, range, or general call address match occurs when the I2C module is in
slave receive mode, the MCU wakes from a low power mode with no peripheral bus
running. Data sent on the bus that is the same as a target device address might also wake
the target MCU.
After the address matching IAAS bit is set, an interrupt is sent at the end of address
matching to wake the core. The IAAS bit must be cleared after the clock recovery.
NOTE
After the system recovers and is in Run mode, restart the I2C
module if it is needed to transfer packets. The SCL line is not
held low until the I2C module resets after address matching.
The main purpose of this feature is to wake the MCU from a
low power mode where no peripheral bus is running. When the
MCU is in such a mode: addressing as a slave, slave read/write,
and sending an acknowledge bit are not fully supported. To
avoid I2C transfer problems resulting from this situation,
firmware should prevent the MCU execution of a STOP
instruction when the I2C module is in the middle of a transfer
unless the Stop mode holdoff feature is used during this period
(set FLT[SHEN] to 1).

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38.4.9 DMA support
If the DMAEN bit is cleared and the IICIE bit is set, an interrupt condition generates an
interrupt request. If the DMAEN bit is set and the IICIE bit is set, an interrupt condition
generates a DMA request instead. DMA requests are generated by the transfer complete
flag (TCF).
If the DMAEN bit is set, the only arbitration lost is to another I2C module (error), and
SCL low timeouts (error) generate CPU interrupts. All other events initiate a DMA
transfer.
NOTE
Before the last byte of master receive mode, TXAK must be set
to send a NACK after the last byte’s transfer. Therefore, the
DMA must be disabled before the last byte’s transfer.
NOTE
In 10-bit address mode transmission, the addresses to send
occupy 2-3 bytes. During this transfer period, the DMA must be
disabled because the C1 register is written to send a repeat start
or to change the transfer direction.

38.5 Initialization/application information
Module Initialization (Slave)
1. Write: Control Register 2
• to enable or disable general call
• to select 10-bit or 7-bit addressing mode
2. Write: Address Register 1 to set the slave address
3. Write: Control Register 1 to enable the I2C module and interrupts
4. Initialize RAM variables (IICEN = 1 and IICIE = 1) for transmit data
5. Initialize RAM variables used to achieve the routine shown in the following figure
Module Initialization (Master)
1. Write: Frequency Divider register to set the I2C baud rate (see example in
description of ICR)
2. Write: Control Register 1 to enable the I2C module and interrupts
3. Initialize RAM variables (IICEN = 1 and IICIE = 1) for transmit data
4. Initialize RAM variables used to achieve the routine shown in the following figure
5. Write: Control Register 1 to enable TX
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Chapter 38 Inter-Integrated Circuit (I2C)

6. Write: Control Register 1 to enable MST (master mode)
7. Write: Data register with the address of the target slave (the LSB of this byte
determines whether the communication is master receive or transmit)
The routine shown in the following figure encompasses both master and slave I2C
operations. For slave operation, an incoming I2C message that contains the proper
address begins I2C communication. For master operation, communication must be
initiated by writing the Data register.

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Initialization/application information

Clear IICIF

Y

Tx

Master
mode?

N

Rx

Y

Tx/Rx?
Last byte
transmitted?

Y

Arbitration
lost?
N

Clear ARBL

N
N

Last byte
to be read?

RXAK=0?

N

End of
address cycle
(master Rx)?

Y

Y
(read)

2nd to
last byte to be
read?

Write next
byte to Data reg

Set TXACK

Address transfer
see note 1

N Data transfer
see note 2

Tx/Rx?
Tx

Y

Generate stop
signal (MST=0)

IIAAS=1?

Rx
SRW=1?
N (write)

N

N

Y

IIAAS=1?
Y

N

Y
Y

Y

Set TX mode

ACK from
receiver?
N

Write data
to Data reg

Switch to
Rx mode

Dummy read
from Data reg

Generate stop
signal (MST=0)

Read data from
Data reg
and store

Read data from
Data reg
and store

Transmit
next byte

Set Rx mode

Switch to
Rx mode

Dummy read
from Data reg

Dummy read
from Data reg

RTI

Notes:
1. If general call is enabled, check to determine if the received address is a general call address (0x00).
If the received address is a general call address, the general call must be handled by user software.
2. When 10-bit addressing addresses a slave, the slave sees an interrupt following the first byte of the extended address.
Ensure that for this interrupt, the contents of the Data register are ignored and not treated as a valid data transfer.

Figure 38-42. Typical I2C interrupt routine

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Chapter 38 Inter-Integrated Circuit (I2C)

Y

N

SLTF or
SHTF2=1?

N
FACK=1?

See typical I2C
interrupt routine
flow chart

Y

Clear IICIF
Y

Tx

Master
mode?

N

Rx

Y

Tx/Rx?
Last byte
transmitted?

Y

Last byte
to be read?

Y

N
RXAK=0?

2nd to
last byte to be
read?

N

N

Y

Y
(read)

N

Delay (note 2)
Read data and
Soft CRC
Set TXAK to
proper value
Delay (note 2)
Set TXACK=1
Clear FACK=0

Clear IICIF

Write next
byte to Data reg

Switch to
Rx mode

Generate stop
signal (MST=0)

Y

IAAS=1?
Y

Delay (note 2)
Read data from
Data reg
and soft CRC

End of
address cycle
(master Rx)?

Dummy read
from Data reg

N

Clear ARBL

N

N

Y

Y

Arbitration
lost?

Address transfer
see note 1

SRW=1?

Rx

N (write)

Delay (note 2)
Read data from
Data reg
and soft CRC

Generate stop
signal (MST=0)

IAAS=1?

N

Tx/Rx?
Tx

ACK from
receiver?
N

Set TXAK to
proper value

Set TXAK to
proper value
Clear IICIF
Delay (note 2)

Delay (note 2)
Read data from
Data reg
and soft CRC

Clear IICIF
Delay (note 2)

Set Tx mode

Set TXAK to
proper value
Clear IICIF
Delay (note 2)

Switch to
Rx mode

Read data from
Data reg
and store

Write data
to Data reg

Read data from
Data reg
and store

Dummy read
from Data reg

Y

Clear IICIF

Transmit
next byte

RTI

Notes:
1. If general call or SIICAEN is enabled, check to determine if the received address is a general call address (0x00) or an SMBus
device default address. In either case, they must be handled by user software.
2. In receive mode, one bit time delay may be needed before the first and second data reading.

Figure 38-43. Typical I2C SMBus interrupt routine

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Chapter 39
Universal Asynchronous Receiver/Transmitter
(UART0)
39.1 Introduction

39.1.1 Features
Features of the UART module include:
• Full-duplex, standard non-return-to-zero (NRZ) format
• Double-buffered transmitter and receiver with separate enables
• Programmable baud rates (13-bit modulo divider)
• Transmit and receive baud rate can operate asynchronous to the bus clock:
• Baud rate can be configured independently of the bus clock frequency
• Supports operation in Stop modes
• Configurable receiver buad rate oversampling ratio from 4x to 32x
• Interrupt, DMA or polled operation:
• Transmit data register empty and transmission complete
• Receive data register full
• Receive overrun, parity error, framing error, and noise error
• Idle receiver detect
• Active edge on receive pin
• Break detect supporting LIN
• Hardware parity generation and checking
• Programmable 8-bit, 9-bit or 10-bit character length
• Programmable 1-bit or 2-bit stop bits
• Receiver wakeup by idle-line, address-mark or address match
• Optional 13-bit break character generation / 11-bit break character detection
• Selectable transmitter output and receiver input polarity

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Introduction

39.1.2 Modes of operation
39.1.2.1 Stop mode
The UART will remain functional during Stop mode, provided the asynchronous transmit
and receive clock remains enabled. The UART can generate an interrupt or DMA request
to cause a wakeup from Stop mode.

39.1.2.2 Wait mode
The UART can be configured to Stop in Wait modes, when the DOZEEN bit is set. The
transmitter and receiver will finish transmitting/receiving the current word.

39.1.2.3 Debug mode
The UART remains functional in debug mode.

39.1.3 Block diagram
The following figure shows the transmitter portion of the UART.

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Chapter 39 Universal Asynchronous Receiver/Transmitter (UART0)
Internal Bus
(Write-Only)
LOOPS
UART_D – Tx Buffer

RSRC
Loop
Control

Stop

M

Start

11-BIT Transmit Shift Register

8

7

6

5

4

3

2

1

0

To TxD Pin

L

lsb

H

1  Baud
Rate Clock

To Receive
Data In

SHIFT DIRECTION

PT

Break (All 0s)

Parity
Generation

Preamble (All 1s)

PE

Shift Enable

T8

Load From UARTx_D

TXINV

UART Controls TxD

TE
SBK

Transmit Control

TXDIR

TxD Direction

TO TxD
Pin Logic

BRK13

TDRE
TIE
TC

Tx Interrupt
Request

TCIE

Figure 39-1. UART transmitter block diagram

The following figure shows the receiver portion of the UART.

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Register definition
INTERNAL BUS

SBR12:0

RE

STOP

BAUDRATE
GENERATOR

BAUD
CLOCK

START

DATA BUFFER

VARIABLE 12-BIT RECEIVE
SHIFT REGISTER

M
M10
LBKDE
MSBF
RXINV

RECEIVE
CONTROL

RAF

SHIFT DIRECTION
RxD
LOOPS

RECEIVER
SOURCE
CONTROL

RSRC

PE

RxD

PARITY
LOGIC

PT

From Transmitter

WAKEUP
LOGIC

IRQ / DMA
LOGIC

ACTIVE EDGE
DETECT

DMA Requests
IRQ Requests

Figure 39-2. UART receiver block diagram

39.2 Register definition
The UART includes registers to control baud rate, select UART options, report UART
status, and for transmit/receive data. Accesses to address outside the valid memory map
will generate a bus error.
UART memory map
Absolute
address
(hex)

Register name

Width
Access
(in bits)

Reset value

Section/
page

4006_A000

UART Baud Rate Register High (UART0_BDH)

8

R/W

00h

39.2.1/725

4006_A001

UART Baud Rate Register Low (UART0_BDL)

8

R/W

04h

39.2.2/726

4006_A002

UART Control Register 1 (UART0_C1)

8

R/W

00h

39.2.3/726

4006_A003

UART Control Register 2 (UART0_C2)

8

R/W

00h

39.2.4/728

4006_A004

UART Status Register 1 (UART0_S1)

8

R/W

C0h

39.2.5/729

Table continues on the next page...

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Chapter 39 Universal Asynchronous Receiver/Transmitter (UART0)

UART memory map (continued)
Absolute
address
(hex)

Width
Access
(in bits)

Register name

Reset value

Section/
page

4006_A005

UART Status Register 2 (UART0_S2)

8

R/W

00h

39.2.6/731

4006_A006

UART Control Register 3 (UART0_C3)

8

R/W

00h

39.2.7/733

4006_A007

UART Data Register (UART0_D)

8

R/W

00h

39.2.8/734

4006_A008

UART Match Address Registers 1 (UART0_MA1)

8

R/W

00h

39.2.9/735

4006_A009

UART Match Address Registers 2 (UART0_MA2)

8

R/W

00h

39.2.10/
736

4006_A00A UART Control Register 4 (UART0_C4)

8

R/W

0Fh

39.2.11/
736

4006_A00B UART Control Register 5 (UART0_C5)

8

R/W

00h

39.2.12/
737

39.2.1 UART Baud Rate Register High (UARTx_BDH)
This register, along with UART _BDL, controls the prescale divisor for UART baud rate
generation. The 13-bit baud rate setting [SBR12:SBR0] should only be updated when the
transmitter and receiver are both disabled.
Address: Base address + 0h offset
Bit

Read
Write
Reset

7

6

5

LBKDIE

RXEDGIE

SBNS

0

0

0

4

3

2

1

0

0

0

SBR
0

0

0

UARTx_BDH field descriptions
Field
7
LBKDIE

6
RXEDGIE

5
SBNS

Description
LIN Break Detect Interrupt Enable (for LBKDIF)
0
1

Hardware interrupts from UART _S2[LBKDIF] disabled (use polling).
Hardware interrupt requested when UART _S2[LBKDIF] flag is 1.

RX Input Active Edge Interrupt Enable (for RXEDGIF)
0
1

Hardware interrupts from UART _S2[RXEDGIF] disabled (use polling).
Hardware interrupt requested when UART _S2[RXEDGIF] flag is 1.

Stop Bit Number Select
SBNS determines whether data characters are one or two stop bits. This bit should only be changed when
the transmitter and receiver are both disabled.
0
1

One stop bit.
Two stop bit.
Table continues on the next page...

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Register definition

UARTx_BDH field descriptions (continued)
Field
4–0
SBR

Description
Baud Rate Modulo Divisor.
The 13 bits in SBR[12:0] are referred to collectively as BR, and they set the modulo divide rate for the
baud rate generator. When BR is 1 - 8191, the baud rate equals baud clock / ((OSR+1) × BR).

39.2.2 UART Baud Rate Register Low (UARTx_BDL)
This register, along with UART _BDH, control the prescale divisor for UART baud rate
generation. The 13-bit baud rate setting [SBR12:SBR0] can only be updated when the
transmitter and receiver are both disabled.
UART _BDL is reset to a non-zero value, so after reset the baud rate generator remains
disabled until the first time the receiver or transmitter is enabled; that is, UART _C2[RE]
or UART _C2[TE] bits are written to 1.
Address: Base address + 1h offset
Bit

Read
Write
Reset

7

6

5

4

3

2

1

0

0

1

0

0

SBR
0

0

0

0

UARTx_BDL field descriptions
Field
7–0
SBR

Description
Baud Rate Modulo Divisor
These 13 bits in SBR[12:0] are referred to collectively as BR. They set the modulo divide rate for the baud
rate generator. When BR is 1 - 8191, the baud rate equals baud clock/((OSR+1) × BR).

39.2.3 UART Control Register 1 (UARTx_C1)
This read/write register controls various optional features of the UART system. This
register should only be altered when the transmitter and receiver are both disabled.
Address: Base address + 2h offset
Bit

Read
Write
Reset

7

6

5

4

3

2

1

0

LOOPS

DOZEEN

RSRC

M

WAKE

ILT

PE

PT

0

0

0

0

0

0

0

0

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Chapter 39 Universal Asynchronous Receiver/Transmitter (UART0)

UARTx_C1 field descriptions
Field
7
LOOPS

Description
Loop Mode Select
Selects between loop back modes and normal 2-pin full-duplex modes. When LOOPS is set, the
transmitter output is internally connected to the receiver input.
0
1

6
DOZEEN

5
RSRC

Doze Enable
0
1

This bit has no meaning or effect unless the LOOPS bit is set to 1. When LOOPS is set, the receiver input
is internally connected to the UART _TX pin and RSRC determines whether this connection is also
connected to the transmitter output.

1

3
WAKE

2
ILT

0
1

Receiver and transmitter use 8-bit data characters.
Receiver and transmitter use 9-bit data characters.

Receiver Wakeup Method Select
0
1

Idle-line wakeup.
Address-mark wakeup.

Idle Line Type Select
Setting this bit to 1 ensures that the stop bits and logic 1 bits at the end of a character do not count toward
the 10 to 13 bit times of logic high level needed by the idle line detection logic.
Idle character bit count starts after start bit.
Idle character bit count starts after stop bit.

Parity Enable
Enables hardware parity generation and checking. When parity is enabled, the bit immediately before the
stop bit is treated as the parity bit.
0
1

0
PT

Provided LOOPS is set, RSRC is cleared, selects internal loop back mode and the UART does not
use the UART _RX pins.
Single-wire UART mode where the UART _TX pin is connected to the transmitter output and receiver
input.

9-Bit or 8-Bit Mode Select

0
1
1
PE

UART is enabled in Wait mode.
UART is disabled in Wait mode.

Receiver Source Select

0

4
M

Normal operation - UART _RX and UART _TX use separate pins.
Loop mode or single-wire mode where transmitter outputs are internally connected to receiver input.
(See RSRC bit.) UART _RX pin is not used by UART .

No hardware parity generation or checking.
Parity enabled.

Parity Type
Provided parity is enabled (PE = 1), this bit selects even or odd parity. Odd parity means the total number
of 1s in the data character, including the parity bit, is odd. Even parity means the total number of 1s in the
data character, including the parity bit, is even.
0
1

Even parity.
Odd parity.

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Register definition

39.2.4 UART Control Register 2 (UARTx_C2)
This register can be read or written at any time.
Address: Base address + 3h offset
Bit

Read
Write
Reset

7

6

5

4

3

2

1

0

TIE

TCIE

RIE

ILIE

TE

RE

RWU

SBK

0

0

0

0

0

0

0

0

UARTx_C2 field descriptions
Field
7
TIE

6
TCIE

Description
Transmit Interrupt Enable for TDRE
0
1

Hardware interrupts from TDRE disabled; use polling.
Hardware interrupt requested when TDRE flag is 1.

Transmission Complete Interrupt Enable for TC
0
1

Hardware interrupts from TC disabled; use polling.
Hardware interrupt requested when TC flag is 1.

5
RIE

Receiver Interrupt Enable for RDRF

4
ILIE

Idle Line Interrupt Enable for IDLE

3
TE

Transmitter Enable

0
1

0
1

Hardware interrupts from RDRF disabled; use polling.
Hardware interrupt requested when RDRF flag is 1.

Hardware interrupts from IDLE disabled; use polling.
Hardware interrupt requested when IDLE flag is 1.

TE must be 1 to use the UART transmitter. When TE is set, the UART forces the UART _TX pin to act as
an output for the UART system.
When the UART is configured for single-wire operation (LOOPS = RSRC = 1), TXDIR controls the
direction of traffic on the single UART communication line ( UART _TX pin).
TE can also queue an idle character by clearing TE then setting TE while a transmission is in progress.
When TE is written to 0, the transmitter keeps control of the port UART _TX pin until any data, queued
idle, or queued break character finishes transmitting before allowing the pin to tristate.
0
1

2
RE

Transmitter disabled.
Transmitter enabled.

Receiver Enable
When the UART receiver is off or LOOPS is set, the UART _RX pin is not used by the UART .
When RE is written to 0, the receiver finishes receiving the current character (if any).
0
1

1
RWU

Receiver disabled.
Receiver enabled.

Receiver Wakeup Control
Table continues on the next page...

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Chapter 39 Universal Asynchronous Receiver/Transmitter (UART0)

UARTx_C2 field descriptions (continued)
Field

Description
This bit can be written to 1 to place the UART receiver in a standby state where it waits for automatic
hardware detection of a selected wakeup condition. The wakeup condition is an idle line between
messages, WAKE = 0, idle-line wakeup, or a logic 1 in the most significant data bit in a character, WAKE =
1, address-mark wakeup. Application software sets RWU and, normally, a selected hardware condition
automatically clears RWU.
0
1

0
SBK

Normal UART receiver operation.
UART receiver in standby waiting for wakeup condition.

Send Break
Writing a 1 and then a 0 to SBK queues a break character in the transmit data stream. Additional break
characters of 10 to 13, or 13 to 16 if BRK13 = 1, bit times of logic 0 are queued as long as SBK is set.
Depending on the timing of the set and clear of SBK relative to the information currently being transmitted,
a second break character may be queued before software clears SBK.
0
1

Normal transmitter operation.
Queue break character(s) to be sent.

39.2.5 UART Status Register 1 (UARTx_S1)
Address: Base address + 4h offset
Bit

Read

7

6

5

4

3

2

1

0

TDRE

TC

RDRF

IDLE

OR

NF

FE

PF

w1c

w1c

w1c

w1c

w1c

0

0

0

0

0

Write
Reset

1

1

0

UARTx_S1 field descriptions
Field
7
TDRE

Description
Transmit Data Register Empty Flag
TDRE is set out of reset and whenever there is room to write data to the transmit data buffer. To clear
TDRE, write to the UART data register ( UART _D).
0
1

6
TC

Transmit data buffer full.
Transmit data buffer empty.

Transmission Complete Flag
TC is set out of reset and when TDRE is set and no data, preamble, or break character is being
transmitted.
TC is cleared automatically by one of the following:
• Write to the UART data register ( UART _D) to transmit new data
• Queue a preamble by changing TE from 0 to 1
• Queue a break character by writing 1 to UART _C2[SBK]
0
1

Transmitter active (sending data, a preamble, or a break).
Transmitter idle (transmission activity complete).
Table continues on the next page...

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UARTx_S1 field descriptions (continued)
Field
5
RDRF

Description
Receive Data Register Full Flag
RDRF becomes set whenever the receive data buffer is full. To clear RDRF, read the UART data register
( UART _D).
0
1

4
IDLE

Receive data buffer empty.
Receive data buffer full.

Idle Line Flag
IDLE is set when the UART receive line becomes idle for a full character time after a period of activity.
When ILT is cleared, the receiver starts counting idle bit times after the start bit. If the receive character is
all 1s, these bit times and the stop bits time count toward the full character time of logic high, 10 to 13 bit
times, needed for the receiver to detect an idle line. When ILT is set, the receiver doesn't start counting
idle bit times until after the stop bits. The stop bits and any logic high bit times at the end of the previous
character do not count toward the full character time of logic high needed for the receiver to detect an idle
line.
To clear IDLE, write logic 1 to the IDLE flag. After IDLE has been cleared, it cannot become set again until
after a new character has been received and RDRF has been set. IDLE is set only once even if the
receive line remains idle for an extended period.
0
1

3
OR

Receiver Overrun Flag
OR is set when a new serial character is ready to be transferred to the receive data buffer, but the
previously received character has not been read from UART _D yet. In this case, the new character, and
all associated error information, is lost because there is no room to move it into UART _D. To clear OR,
write a logic 1 to the OR flag.
0
1

2
NF

The advanced sampling technique used in the receiver takes three samples in each of the received bits. If
any of these samples disagrees with the rest of the samples within any bit time in the frame, the flag NF is
set at the same time as RDRF is set for the character. To clear NF, write logic one to the NF.
No noise detected.
Noise detected in the received character in UART _D.

Framing Error Flag
FE is set at the same time as RDRF when the receiver detects a logic 0 where a stop bit was expected.
This suggests the receiver was not properly aligned to a character frame. To clear FE, write a logic one to
the FE flag.
0
1

0
PF

No overrun.
Receive overrun (new UART data lost).

Noise Flag

0
1
1
FE

No idle line detected.
Idle line was detected.

No framing error detected. This does not guarantee the framing is correct.
Framing error.

Parity Error Flag
PF is set at the same time as RDRF when parity is enabled (PE = 1) and the parity bit in the received
character does not agree with the expected parity value. To clear PF, write a logic one to the PF.
Table continues on the next page...

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UARTx_S1 field descriptions (continued)
Field

Description
0
1

No parity error.
Parity error.

39.2.6 UART Status Register 2 (UARTx_S2)
This register contains one read-only status flag.
When using an internal oscillator in a LIN system, it is necessary to raise the break
detection threshold one bit time. Under the worst case timing conditions allowed in LIN,
it is possible that a 0x00 data character can appear to be 10.26 bit times long at a slave
running 14% faster than the master. This would trigger normal break detection circuitry
designed to detect a 10-bit break symbol. When the LBKDE bit is set, framing errors are
inhibited and the break detection threshold increases, preventing false detection of a 0x00
data character as a LIN break symbol.
Address: Base address + 5h offset
Bit

Read
Write
Reset

7

6

5

4

3

2

1

LBKDIF

RXEDGIF

MSBF

RXINV

RWUID

BRK13

LBKDE

0

0

0

0

0

0

0

0

RAF

0

UARTx_S2 field descriptions
Field
7
LBKDIF

Description
LIN Break Detect Interrupt Flag
LBKDIF is set when the LIN break detect circuitry is enabled and a LIN break character is detected.
LBKDIF is cleared by writing a 1 to it.
0
1

6
RXEDGIF

UART _RX Pin Active Edge Interrupt Flag
RXEDGIF is set when an active edge, falling if RXINV = 0, rising if RXINV=1, on the UART _RX pin
occurs. RXEDGIF is cleared by writing a 1 to it.
0
1

5
MSBF

No LIN break character has been detected.
LIN break character has been detected.

No active edge on the receive pin has occurred.
An active edge on the receive pin has occurred.

MSB First
Setting this bit reverses the order of the bits that are transmitted and received on the wire. This bit does
not affect the polarity of the bits, the location of the parity bit or the location of the start or stop bits. This bit
should only be changed when the transmitter and receiver are both disabled.
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UARTx_S2 field descriptions (continued)
Field

Description
0
1

4
RXINV

LSB (bit0) is the first bit that is transmitted following the start bit. Further, the first bit received after the
start bit is identified as bit0.
MSB (bit9, bit8, bit7 or bit6) is the first bit that is transmitted following the start bit depending on the
setting of C1[M], C1[PE] and C4[M10]. Further, the first bit received after the start bit is identified as
bit9, bit8, bit7 or bit6 depending on the setting of C1[M] and C1[PE].

Receive Data Inversion
Setting this bit reverses the polarity of the received data input.
NOTE: Setting RXINV inverts the UART _RXD input for all cases: data bits, start and stop bits, break,
and idle.
0
1

3
RWUID

Receive Wake Up Idle Detect
RWUID controls whether the idle character that wakes up the receiver sets the IDLE bit. This bit should
only be changed when the receiver is disabled.
0
1

2
BRK13

BRK13 selects a longer transmitted break character length. Detection of a framing error is not affected by
the state of this bit. This bit should only be changed when the transmitter is disabled.

1

Break character is transmitted with length of 10 bit times (if M = 0, SBNS = 0) or 11 (if M = 1, SBNS =
0 or M = 0, SBNS = 1) or 12 (if M = 1, SBNS = 1 or M10 = 1, SNBS = 0) or 13 (if M10 = 1, SNBS = 1).
Break character is transmitted with length of 13 bit times (if M = 0, SBNS = 0) or 14 (if M = 1, SBNS =
0 or M = 0, SBNS = 1) or 15 (if M = 1, SBNS = 1 or M10 = 1, SNBS = 0) or 16 (if M10 = 1, SNBS = 1).

LIN Break Detection Enable
LBKDE selects a longer break character detection length. While LBKDE is set, framing error (FE) and
receive data register full (RDRF) flags are prevented from setting.
0
1

0
RAF

During receive standby state (RWU = 1), the IDLE bit does not get set upon detection of an idle
character.
During receive standby state (RWU = 1), the IDLE bit gets set upon detection of an idle character.

Break Character Generation Length

0

1
LBKDE

Receive data not inverted.
Receive data inverted.

Break character is detected at length 10 bit times (if M = 0, SBNS = 0) or 11 (if M = 1, SBNS = 0 or M
= 0, SBNS = 1) or 12 (if M = 1, SBNS = 1 or M10 = 1, SNBS = 0) or 13 (if M10 = 1, SNBS = 1).
Break character is detected at length of 11 bit times (if M = 0, SBNS = 0) or 12 (if M = 1, SBNS = 0 or
M = 0, SBNS = 1) or 14 (if M = 1, SBNS = 1 or M10 = 1, SNBS = 0) or 15 (if M10 = 1, SNBS = 1).

Receiver Active Flag
RAF is set when the UART receiver detects the beginning of a valid start bit, and RAF is cleared
automatically when the receiver detects an idle line.
0
1

UART receiver idle waiting for a start bit.
UART receiver active ( UART _RXD input not idle).

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Chapter 39 Universal Asynchronous Receiver/Transmitter (UART0)

39.2.7 UART Control Register 3 (UARTx_C3)
Address: Base address + 6h offset
Bit

Read
Write
Reset

7

6

5

4

3

2

1

0

R8T9

R9T8

TXDIR

TXINV

ORIE

NEIE

FEIE

PEIE

0

0

0

0

0

0

0

0

UARTx_C3 field descriptions
Field
7
R8T9

Description
Receive Bit 8 / Transmit Bit 9
When the UART is configured for 9-bit data (M = 1), R8 can be thought of as a ninth receive data bit to the
left of the msb of the buffered data in the UART_D register. When reading 9-bit data, read R8 before
reading UART_D because reading UART_D completes automatic flag clearing sequences that could allow
R8 and UART_D to be overwritten with new data.
When the UART is configured for 10-bit data (M10 = 1), T9 may be thought of as a tenth transmit data bit.
When writing 10-bit data, the entire 10-bit value is transferred to the UART transmit buffer when UART_D
is written so T9 and T8 should be written, if it needs to change from its previous value, before UART_D is
written. If T9 and T8 do not need to change in the new value, such as when it is used to generate mark or
space parity, they need not be written each time UART_D is written.

6
R9T8

Receive Bit 9 / Transmit Bit 8
When the UART is configured for 9-bit data (M = 1), T8 may be thought of as a ninth transmit data bit to
the left of the msb of the data in the UART_D register. When writing 9-bit data, the entire 9-bit value is
transferred to the UART transmit buffer after UART_D is written so T8 should be written, if it needs to
change from its previous value, before UART_D is written. If T8 does not need to change in the new value,
such as when it is used to generate mark or space parity, it need not be written each time UART_D is
written.
When the UART is configured for 10-bit data (M10 = 1), R9 can be thought of as a tenth receive data bit.
When reading 10-bit data, read R9 and R8 before reading UART_D because reading UART_D completes
automatic flag clearing sequences that could allow R8, R9 and UART_D to be overwritten with new data.

5
TXDIR

UART _TX Pin Direction in Single-Wire Mode
When the is configured for single-wire half-duplex operation (LOOPS = RSRC = 1), this bit determines the
direction of data at the UART_TXD pin. When clearing TXDIR, the transmitter will finish receiving the
current character (if any) before the receiver starts receiving data from the UART_TXD pin.
0
1

4
TXINV

UART _TXD pin is an input in single-wire mode.
UART _TXD pin is an output in single-wire mode.

Transmit Data Inversion
Setting this bit reverses the polarity of the transmitted data output.
NOTE: Setting TXINV inverts the UART _TXD output for all cases: data bits, start and stop bits, break,
and idle.
0
1

3
ORIE

Transmit data not inverted.
Transmit data inverted.

Overrun Interrupt Enable
This bit enables the overrun flag (OR) to generate hardware interrupt requests.
Table continues on the next page...

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Register definition

UARTx_C3 field descriptions (continued)
Field

Description
0
1

2
NEIE

Noise Error Interrupt Enable
This bit enables the noise flag (NF) to generate hardware interrupt requests.
0
1

1
FEIE

NF interrupts disabled; use polling.
Hardware interrupt requested when NF is set.

Framing Error Interrupt Enable
This bit enables the framing error flag (FE) to generate hardware interrupt requests.
0
1

0
PEIE

OR interrupts disabled; use polling.
Hardware interrupt requested when OR is set.

FE interrupts disabled; use polling.
Hardware interrupt requested when FE is set.

Parity Error Interrupt Enable
This bit enables the parity error flag (PF) to generate hardware interrupt requests.
0
1

PF interrupts disabled; use polling).
Hardware interrupt requested when PF is set.

39.2.8 UART Data Register (UARTx_D)
This register is actually two separate registers. Reads return the contents of the read-only
receive data buffer and writes go to the write-only transmit data buffer. Reads and writes
of this register are also involved in the automatic flag clearing mechanisms for some of
the UART status flags.
Address: Base address + 7h offset
Bit

Read
Write
Reset

7

6

5

4

3

2

1

0

R7T7

R6T6

R5T5

R4T4

R3T3

R2T2

R1T1

R0T0

0

0

0

0

0

0

0

0

UARTx_D field descriptions
Field

Description

7
R7T7

Read receive data buffer 7 or write transmit data buffer 7.

6
R6T6

Read receive data buffer 6 or write transmit data buffer 6.

5
R5T5

Read receive data buffer 5 or write transmit data buffer 5.
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Chapter 39 Universal Asynchronous Receiver/Transmitter (UART0)

UARTx_D field descriptions (continued)
Field

Description

4
R4T4

Read receive data buffer 4 or write transmit data buffer 4.

3
R3T3

Read receive data buffer 3 or write transmit data buffer 3.

2
R2T2

Read receive data buffer 2 or write transmit data buffer 2.

1
R1T1

Read receive data buffer 1 or write transmit data buffer 1.

0
R0T0

Read receive data buffer 0 or write transmit data buffer 0.

39.2.9 UART Match Address Registers 1 (UARTx_MA1)
The MA1 and MA2 registers are compared to input data addresses when the most
significant bit is set and the associated C4[MAEN] bit is set. If a match occurs, the
following data is transferred to the data register. If a match fails, the following data is
discarded. Software should only write a MA register when the associated C4[MAEN] bit
is clear.
Address: Base address + 8h offset
Bit

Read
Write
Reset

7

6

5

4

3

2

1

0

0

0

0

0

MA
0

0

0

0

UARTx_MA1 field descriptions
Field
7–0
MA

Description
Match Address

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39.2.10 UART Match Address Registers 2 (UARTx_MA2)
The MA1 and MA2 registers are compared to input data addresses when the most
significant bit is set and the associated C4[MAEN] bit is set. If a match occurs, the
following data is transferred to the data register. If a match fails, the following data is
discarded. Software should only write a MA register when the associated C4[MAEN] bit
is clear.
Address: Base address + 9h offset
Bit

Read
Write
Reset

7

6

5

4

3

2

1

0

0

0

0

0

2

1

0

1

1

MA
0

0

0

0

UARTx_MA2 field descriptions
Field
7–0
MA

Description
Match Address

39.2.11 UART Control Register 4 (UARTx_C4)
Address: Base address + Ah offset
Bit

Read
Write
Reset

7

6

5

MAEN1

MAEN2

M10

0

0

0

4

3

OSR
0

1

1

UARTx_C4 field descriptions
Field
7
MAEN1

Description
Match Address Mode Enable 1
Refer to Match address operation for more information.
0
1

6
MAEN2

All data received is transferred to the data buffer if MAEN2 is cleared.
All data received with the most significant bit cleared, is discarded. All data received with the most
significant bit set, is compared with contents of MA1 register. If no match occurs, the data is
discarded. If match occurs, data is transferred to the data buffer.

Match Address Mode Enable 2
Refer to Match address operation for more information.
0
1

All data received is transferred to the data buffer if MAEN1 is cleared.
All data received with the most significant bit cleared, is discarded. All data received with the most
significant bit set, is compared with contents of MA2 register. If no match occurs, the data is
discarded. If match occurs, data is transferred to the data buffer.
Table continues on the next page...

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Chapter 39 Universal Asynchronous Receiver/Transmitter (UART0)

UARTx_C4 field descriptions (continued)
Field
5
M10

Description
10-bit Mode select
The M10 bit causes a tenth bit to be part of the serial transmission. This bit should only be changed when
the transmitter and receiver are both disabled.
0
1

4–0
OSR

Receiver and transmitter use 8-bit or 9-bit data characters.
Receiver and transmitter use 10-bit data characters.

Over Sampling Ratio
This field configures the oversampling ratio for the receiver between 4x (00011) and 32x (11111). Writing
an invalid oversampling ratio will default to an oversampling ratio of 16 (01111). This field should only be
changed when the transmitter and receiver are both disabled.

39.2.12 UART Control Register 5 (UARTx_C5)
Address: Base address + Bh offset
Bit

Read
Write
Reset

7

6

5

0

TDMAE
0

4

0

2

0

RDMAE

0

3

0

0

1

0

BOTHEDGE

RESYNCDI
S

0

0

0

UARTx_C5 field descriptions
Field
7
TDMAE

Description
Transmitter DMA Enable
TDMAE configures the transmit data register empty flag, S1[TDRE], to generate a DMA request.
0
1

6
Reserved
5
RDMAE

This field is reserved.
This read-only field is reserved and always has the value 0.
Receiver Full DMA Enable
RDMAE configures the receiver data register full flag, S1[RDRF], to generate a DMA request.
0
1

4–2
Reserved
1
BOTHEDGE

DMA request disabled.
DMA request enabled.

DMA request disabled.
DMA request enabled.

This field is reserved.
This read-only field is reserved and always has the value 0.
Both Edge Sampling
Enables sampling of the received data on both edges of the baud rate clock, effectively doubling the
number of times the receiver samples the input data for a given oversampling ratio. This bit must be set for
oversampling ratios between x4 and x7 and is optional for higher oversampling ratios. This bit should only
be changed when the receiver is disabled.
Table continues on the next page...

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Functional description

UARTx_C5 field descriptions (continued)
Field

Description
0
1

0
RESYNCDIS

Receiver samples input data using the rising edge of the baud rate clock.
Receiver samples input data using the rising and falling edge of the baud rate clock.

Resynchronization Disable
When set, disables the resynchronization of the received data word when a data one followed by data
zero transition is detected. This bit should only be changed when the receiver is disabled.
0
1

Resynchronization during received data word is supported
Resynchronization during received data word is disabled

39.3 Functional description
The UART supports full-duplex, asynchronous, NRZ serial communication and
comprises a baud rate generator, transmitter, and receiver block. The transmitter and
receiver operate independently, although they use the same baud rate generator. The
following describes each of the blocks of the UART.

39.3.1 Baud rate generation
A 13-bit modulus counter in the baud rate generator derive the baud rate for both the
receiver and the transmitter. The value from 1 to 8191 written to SBR[12:0] determines
the baud clock divisor for the asynchronous UART baud clock. The SBR bits are in the
UART baud rate registers, BDH and BDL. The baud rate clock drives the receiver, while
the transmitter is driven by the baud rate clock divided by the over sampling ratio.
Depending on the over sampling ratio, the receiver has an acquisition rate of 4 to 32
samples per bit time.
Baud rate generation is subject to two sources of error:
• Integer division of the module clock may not give the exact target frequency.
• Synchronization with the asynchronous UART baud clock can cause phase shift.

39.3.2 Transmitter functional description
This section describes the overall block diagram for the UART transmitter, as well as
specialized functions for sending break and idle characters.

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Chapter 39 Universal Asynchronous Receiver/Transmitter (UART0)

The transmitter output (UART_TX) idle state defaults to logic high, C3[TXINV] is
cleared following reset. The transmitter output is inverted by setting C3[TXINV]. The
transmitter is enabled by setting the C2[TE] bit. This queues a preamble character that is
one full character frame of the idle state. The transmitter then remains idle until data is
available in the transmit data buffer. Programs store data into the transmit data buffer by
writing to the UART data register.
The central element of the UART transmitter is the transmit shift register that is 10-bit to
13 bits long depending on the setting in the C1[M], C2[M10] and BDH[SBNS] control
bits. For the remainder of this section, assume C1[M], C2[M10] and BDH[SBNS] are
cleared, selecting the normal 8-bit data mode. In 8-bit data mode, the shift register holds a
start bit, eight data bits, and a stop bit. When the transmit shift register is available for a
new UART character, the value waiting in the transmit data register is transferred to the
shift register, synchronized with the baud rate clock, and the transmit data register empty
(S1[TDRE]) status flag is set to indicate another character may be written to the transmit
data buffer at UART_D.
If no new character is waiting in the transmit data buffer after a stop bit is shifted out the
UART_TX pin, the transmitter sets the transmit complete flag and enters an idle mode,
with UART_TX high, waiting for more characters to transmit.
Writing 0 to C2[TE] does not immediately disable the transmitter. The current transmit
activity in progress must first be completed. This includes data characters in progress,
queued idle characters, and queued break characters.

39.3.2.1 Send break and queued idle
The UART_C2[SBK] bit sends break characters originally used to gain the attention of
old teletype receivers. Break characters are a full character time of logic 0, 10-bit to 12bit times including the start and stop bits. A longer break of 13-bit times can be enabled
by setting UART_S2[BRK13]. Normally, a program would wait for UART_S1[TDRE]
to become set to indicate the last character of a message has moved to the transmit
shifter, write 1, and then write 0 to the UART_C2[SBK] bit. This action queues a break
character to be sent as soon as the shifter is available. If UART_C2[SBK] remains 1
when the queued break moves into the shifter, synchronized to the baud rate clock, an
additional break character is queued. If the receiving device is another Freescale
Semiconductor UART, the break characters are received as 0s in all data bits and a
framing error (UART_S1[FE] = 1) occurs.
When idle-line wakeup is used, a full character time of idle (logic 1) is needed between
messages to wake up any sleeping receivers. Normally, a program would wait for
UART_S1[TDRE] to become set to indicate the last character of a message has moved to
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Functional description

the transmit shifter, then write 0 and then write 1 to the UART_C2[TE] bit. This action
queues an idle character to be sent as soon as the shifter is available. As long as the
character in the shifter does not finish whileUART_C2[TE] is cleared, the UART
transmitter never actually releases control of the UART_TX pin.
The length of the break character is affected by the UART_S2[BRK13], UART_C1[M]
and UART_C4[M10] bits as shown below.
Table 39-27. Break character length
BRK13

M

M10

SBNS

Break character
length

0

0

0

0

10 bit times

0

0

0

1

11 bit times

0

1

0

0

11 bit times

0

1

0

1

12 bit times

0

X

1

0

12 bit times

0

X

1

1

13 bit times

1

0

0

0

13 bit times

1

0

0

1

14 bit times

1

1

0

0

14 bit times

1

1

0

1

15 bit times

1

X

1

0

15 bit times

1

X

1

1

16 bit times

39.3.3 Receiver functional description
In this section, the receiver block diagram is a guide for the overall receiver functional
description. Next, the data sampling technique used to reconstruct receiver data is
described in more detail. Finally, two variations of the receiver wakeup function are
explained.
The receiver input is inverted by setting UART_S2[RXINV]. The receiver is enabled by
setting the UART_C2[RE] bit. Character frames consist of a start bit of logic 0, eight to
ten data bits (msb or lsb first), and one or two stop bits of logic 1. For information about
9-bit or 10-bit data mode, refer to 8-bit, 9-bit and 10-bit data modes. For the remainder of
this discussion, assume the UART is configured for normal 8-bit data mode.
After receiving the stop bit into the receive shifter, and provided the receive data register
is not already full, the data character is transferred to the receive data register and the
receive data register full (UART_S1[RDRF]) status flag is set. If UART_S1[RDRF] was
already set indicating the receive data register (buffer) was already full, the overrun (OR)
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Chapter 39 Universal Asynchronous Receiver/Transmitter (UART0)

status flag is set and the new data is lost. Because the UART receiver is double-buffered,
the program has one full character time after UART_S1[RDRF] is set before the data in
the receive data buffer must be read to avoid a receiver overrun.
When a program detects that the receive data register is full (UART_S1[RDRF] = 1), it
gets the data from the receive data register by reading UART_D. Refer to Interrupts and
status flags for details about flag clearing.

39.3.3.1 Data sampling technique
The UART receiver supports an oversampling rate of between 4× and 32× of the baud
rate clock for sampling. The receiver starts by taking logic level samples at the
oversampling rate times the baud rate to search for a falling edge on the UART_RX serial
data input pin. A falling edge is defined as a logic 0 sample after three consecutive logic
1 samples. The oversampling baud rate clock divides the bit time into 4 to 32 segments
from 1 to OSR (where OSR is the configured oversampling ratio). When a falling edge is
located, three more samples are taken at (OSR/2), (OSR/2)+1, and (OSR/2)+2 to make
sure this was a real start bit and not merely noise. If at least two of these three samples
are 0, the receiver assumes it is synchronized to a receive character. If another falling
edge is detected before the receiver is considered synchronized, the receiver restarts the
sampling from the first segment.
The receiver then samples each bit time, including the start and stop bits, at (OSR/2),
(OSR/2)+1, and (OSR/2)+2 to determine the logic level for that bit. The logic level is
interpreted to be that of the majority of the samples taken during the bit time. If any
sample in any bit time, including the start and stop bits, in a character frame fails to agree
with the logic level for that bit, the noise flag (UART_S1[NF]) is set when the received
character is transferred to the receive data buffer.
When the UART receiver is configured to sample on both edges of the baud rate clock,
the number of segments in each received bit is effectively doubled (from 1 to OSR*2).
The start and data bits are then sampled at OSR, OSR+1 and OSR+2. Sampling on both
edges of the clock must be enabled for oversampling rates of 4× to 7× and is optional for
higher oversampling rates.
The falling edge detection logic continuously looks for falling edges. If an edge is
detected, the sample clock is resynchronized to bit times (unless resynchronization has
been disabled). This improves the reliability of the receiver in the presence of noise or
mismatched baud rates. It does not improve worst case analysis because some characters
do not have any extra falling edges anywhere in the character frame.

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Functional description

In the case of a framing error, provided the received character was not a break character,
the sampling logic that searches for a falling edge is filled with three logic 1 samples so
that a new start bit can be detected almost immediately.

39.3.3.2 Receiver wakeup operation
Receiver wakeup is a hardware mechanism that allows an UART receiver to ignore the
characters in a message intended for a different UART receiver. In such a system, all
receivers evaluate the first character(s) of each message, and as soon as they determine
the message is intended for a different receiver, they write logic 1 to the receiver wake up
control bit(UART_C2[RWU]). When RWU bit is set, the status flags associated with the
receiver, with the exception of the idle bit, IDLE, when UART_S2[RWUID] bit is set,
are inhibited from setting, thus eliminating the software overhead for handling the
unimportant message characters. At the end of a message, or at the beginning of the next
message, all receivers automatically force UART_C2[RWU] to 0 so all receivers wake
up in time to look at the first character(s) of the next message.
39.3.3.2.1

Idle-line wakeup

When wake is cleared, the receiver is configured for idle-line wakeup. In this mode,
UART_C2[RWU] is cleared automatically when the receiver detects a full character time
of the idle-line level. The UART_C1[M] and UART_C4[M10] control bit selects 8-bit to
10-bit data mode and the UART_BDH[SBNS] bit selects 1-bit or 2-bit stop bit number
that determines how many bit times of idle are needed to constitute a full character time,
10 to 13 bit times because of the start and stop bits.
When UART_C2[RWU] is one and UART_S2[RWUID] is zero, the idle condition that
wakes up the receiver does not set the UART_S1[IDLE] flag. The receiver wakes up and
waits for the first data character of the next message that sets the UART_S1[RDRF] flag
and generates an interrupt if enabled. When UART_S2[RWUID] is one, any idle
condition sets the UART_S1[IDLE] flag and generates an interrupt if enabled, regardless
of whether UART_C2[RWU] is zero or one.
The idle-line type (UART_C1[ILT]) control bit selects one of two ways to detect an idle
line. When UART_C1[ILT] is cleared, the idle bit counter starts after the start bit so the
stop bit and any logic 1s at the end of a character count toward the full character time of
idle. When UART_C1[ILT] is set, the idle bit counter does not start until after the stop bit
time, so the idle detection is not affected by the data in the last character of the previous
message.

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Chapter 39 Universal Asynchronous Receiver/Transmitter (UART0)

39.3.3.2.2

Address-mark wakeup

When wake is set, the receiver is configured for address-mark wakeup. In this mode,
UART_C2[RWU] is cleared automatically when the receiver detects a logic 1 in the most
significant bit of a received character.
Address-mark wakeup allows messages to contain idle characters, but requires the msb
be reserved for use in address frames. The logic 1 in the msb of an address frame clears
the UART_C2[RWU] bit before the stop bits are received and sets the UART_S1[RDRF]
flag. In this case, the character with the msb set is received even though the receiver was
sleeping during most of this character time.
39.3.3.2.3

Match address operation

Match address operation is enabled when the UART_C4[MAEN1] or
UART_C4[MAEN2] bit is set. In this function, a frame received by the UART_RX pin
with a logic 1 in the bit position immediately preceding the stop bit is considered an
address and is compared with the associated MA1 or MA2 register. The frame is only
transferred to the receive buffer, and UART_S1[RDRF] is set, if the comparison matches.
All subsequent frames received with a logic 0 in the bit position immediately preceding
the stop bit are considered to be data associated with the address and are transferred to the
receive data buffer. If no marked address match occurs then no transfer is made to the
receive data buffer, and all following frames with logic zero in the bit position
immediately preceding the stop bit are also discarded. If both the UART_C4[MAEN1]
and UART_C4[MAEN2] bits are negated, the receiver operates normally and all data
received is transferred to the receive data buffer.
Match Address operation functions in the same way for both MA1 and MA2 registers.
• If only one of UART_C4[MAEN1] and UART_C4[MAEN2] is asserted, a marked
address is compared only with the associated match register and data is transferred to
the receive data buffer only on a match.
• If UART_C4[MAEN1] and UART_C4[MAEN2] are asserted, a marked address is
compared with both match registers and data is transferred only on a match with
either register.

39.3.4 Additional UART functions
The following sections describe additional UART functions.

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Functional description

39.3.4.1 8-bit, 9-bit and 10-bit data modes
The UART system, transmitter and receiver, can be configured to operate in 9-bit data
mode by setting the UART_C1[M] or 10-bit data mode by setting UART_C4[M10]. In 9bit mode, there is a ninth data bit to the left of the msb of the UART data register, in 10bit mode there is a tenth data bit. For the transmit data buffer, these bits are stored in T8
and T9 in UART_C3. For the receiver, these bits are held in UART_C3[R8] and
UART_C3[R9].
For coherent writes to the transmit data buffer, write to UART_C3[T8] and
UART_C3[T9] before writing to UART_D.
If the bit values to be transmitted as the ninth and tenth bit of a new character are the
same as for the previous character, it is not necessary to write to T8 and T9 again. When
data is transferred from the transmit data buffer to the transmit shifter, the value in T8
and T9 is copied at the same time data is transferred from UART_D to the shifter.
The 9-bit data mode is typically used with parity to allow eight bits of data plus the parity
in the ninth bit, or it is used with address-mark wakeup so the ninth data bit can serve as
the wakeup bit. The 10-bit data mode is typically used with parity and address-mark
wakeup so the ninth data bit can serve as the wakeup bit and the tenth bit as the parity bit.
In custom protocols, the ninth and/or tenth bits can also serve as software-controlled
markers.

39.3.4.2 Loop mode
When UART_C1[LOOPS] is set, the UART_C1[RSRC] bit in the same register chooses
between loop mode (UART_C1[RSRC] = 0) or single-wire mode (UART_C1[RSRC] =
1). Loop mode is sometimes used to check software, independent of connections in the
external system, to help isolate system problems. In this mode, the transmitter output is
internally connected to the receiver input and the UART_RX pin is not used by the
UART.

39.3.4.3 Single-wire operation
When UART_C1[LOOPS] is set, the RSRC bit in the same register chooses between
loop mode (UART_C1[RSRC] = 0) or single-wire mode (UART_C1[RSRC] = 1).
Single-wire mode implements a half-duplex serial connection. The receiver is internally
connected to the transmitter output and to the UART_TX pin (the UART_RX pin is not
used).

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Chapter 39 Universal Asynchronous Receiver/Transmitter (UART0)

In single-wire mode, the UART_C3[TXDIR] bit controls the direction of serial data on
the UART_TX pin. When UART_C3[TXDIR] is cleared, the UART_TX pin is an input
to the UART receiver and the transmitter is temporarily disconnected from the
UART_TX pin so an external device can send serial data to the receiver. When
UART_C3[TXDIR] is set, the UART_TXD pin is an output driven by the transmitter, the
internal loop back connection is disabled, and as a result the receiver cannot receive
characters that are sent out by the transmitter.

39.3.5 Interrupts and status flags
The UART system generates three separate interrupts to reduce the amount of software
needed to isolate the cause of the interrupt. One interrupt is associated with the
transmitter for TDRE and TC events. Another interrupt is associated with the receiver for
RDRF, IDLE, RXEDGIF, and LBKDIF events. A third interrupt is used for OR, NF, FE,
and PF error conditions. Each of these ten interrupt sources can be separately masked by
local interrupt enable masks. The flags can be polled by software when the local masks
are cleared to disable generation of hardware interrupt requests.
The UART transmitter has two status flags that can optionally generate hardware
interrupt requests. Transmit data register empty (UART_S1[TDRE]) indicates when there
is room in the transmit data buffer to write another transmit character to UART_D. If the
transmit interrupt enable (UART_C2[TIE]) bit is set, a hardware interrupt is requested
when UART_S1[TDRE] is set. Transmit complete (UART_S1[TC]) indicates that the
transmitter is finished transmitting all data, preamble, and break characters and is idle
with UART_TX at the inactive level. This flag is often used in systems with modems to
determine when it is safe to turn off the modem. If the transmit complete interrupt enable
(UART_C2[TCIE]) bit is set, a hardware interrupt is requested when UART_S1[TC] is
set. Instead of hardware interrupts, software polling may be used to monitor the
UART_S1[TDRE] and UART_S1[TC] status flags if the corresponding UART_C2[TIE]
or UART_C2[TCIE] local interrupt masks are cleared.
When a program detects that the receive data register is full (UART_S1[RDRF] = 1), it
gets the data from the receive data register by reading UART_D. The UART_S1[RDRF]
flag is cleared by reading UART_D.
The IDLE status flag includes logic that prevents it from getting set repeatedly when the
UART_RX line remains idle for an extended period of time. IDLE is cleared by writing 1
to the UART_S1[IDLE] flag. After UART_S1[IDLE] has been cleared, it cannot become
set again until the receiver has received at least one new character and has set
UART_S1[RDRF].

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Functional description

If the associated error was detected in the received character that caused
UART_S1[RDRF] to be set, the error flags - noise flag (UART_S1[NF]), framing error
(UART_S1[FE]), and parity error flag (UART_S1[PF]) - are set at the same time as
UART_S1[RDRF]. These flags are not set in overrun cases.
If UART_S1[RDRF] was already set when a new character is ready to be transferred
from the receive shifter to the receive data buffer, the overrun (UART_S1[OR]) flag is
set instead of the data along with any associated NF, FE, or PF condition is lost.
At any time, an active edge on the UART_RX serial data input pin causes the
UART_S2[RXEDGIF] flag to set. The UART_S2[RXEDGIF] flag is cleared by writing a
1 to it. This function depends on the receiver being enabled (UART_C2[RE] = 1).

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Chapter 40
Universal Asynchronous Receiver/Transmitter
(UART1 and UART2)
40.1 Introduction

40.1.1 Features
Features of UART module include:
• Full-duplex, standard non-return-to-zero (NRZ) format
• Double-buffered transmitter and receiver with separate enables
• Programmable baud rates (13-bit modulo divider)
• Interrupt-driven or polled operation:
• Transmit data register empty and transmission complete
• Receive data register full
• Receive overrun, parity error, framing error, and noise error
• Idle receiver detect
• Active edge on receive pin
• Break detect supporting LIN
• Hardware parity generation and checking
• Programmable 8-bit or 9-bit character length
• Programmable 1-bit or 2-bit stop bits
• Receiver wakeup by idle-line or address-mark
• Optional 13-bit break character generation / 11-bit break character detection
• Selectable transmitter output polarity
• 5-channel DMA interface

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Introduction

40.1.2 Modes of operation
See Section Functional description for details concerning UART operation in these
modes:
• 8- and 9-bit data modes
• Stop mode operation
• Loop mode
• Single-wire mode

40.1.3 Block diagram
The following figure shows the transmitter portion of the UART.
INTERNAL BUS

÷ 16

7

T8
PE

PARITY
GENERATION

PT

6

5

4

3

2

1

START

0

TxD

L

SHIFT DIRECTION

MSB

TXINV

8

TXINV

LOOP
CONTROL
BREAK (ALL 0s)

H

M

11-BIT TRANSMIT SHIFT REGISTER

PREAMBLE (ALL 1s)

STOP

SBR12–SBR0

UART DATA REGISTER (UART_D)

SHIFT ENABLE

BAUD DIVIDER

LOAD FROM UART_D

MODULE
CLOCK

LOOPS
RSRC
TxD Pin Control
Tx Pin Logic

TRANSMITTER CONTROL

TDRE INTERRUPT/DMA
REQUEST
TC INTERRUPT/DMA
REQUEST

TDRE

TE

SBK

TO
RECEIVER

DMA done

TXDIR

TIE
TC
TCIE

Figure 40-1. UART transmitter block diagram

The following figure shows the receiver portion of the UART.

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Chapter 40 Universal Asynchronous Receiver/Transmitter (UART1 and UART2)
INTERNAL BUS

SBR12–SBR0

RE

DATA
RECOVERY

FROM
TRANSMITTER
LOOPS

SINGLE-WIRE
LOOP CONTROL

RSRC

ALL 1s

M
LBKDE

WAKE
ILT

8

7

6

5

4

3

2

1

0

L

SHIFT DIRECTION
MSB

RAF

11-BIT RECEIVE SHIFT REGISTER

H

START

BAUD DIVIDER

STOP

MODULE
CLOCK

UART DATA REGISTER (UART_D)

WAKEUP
LOGIC

RWU

RWUID

From RxD Pin
RXINV
RDRF
RIE
IDLE
ILIE

ACTIVE EDGE
DETECT

LBKDIF

Rx
Interrupt/DMA
Request

LBKDIE
RXEDGIF
RXEDGIE

OR

R8

ORIE
FE
FEIE
NF
NEIE

PE
PT

PARITY
CHECKING

Error
Interrupt
Requestt

PF
PEIE

Figure 40-2. UART receiver block diagram

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Register definition

40.2 Register definition
The UART has 8-bit registers to control baud rate, select UART options, report UART
status, select DMA options, and for transmit/receive data.
Refer to the direct-page register summary in the memory chapter of this document or the
absolute address assignments for all UART registers. This section refers to registers and
control bits only by their names. A Freescale-provided equate or header file is used to
translate these names into the appropriate absolute addresses.
UART memory map
Absolute
address
(hex)

Register name

Width
Access
(in bits)

Reset value

Section/
page

4006_B000

UART Baud Rate Register: High (UART1_BDH)

8

R/W

00h

40.2.1/751

4006_B001

UART Baud Rate Register: Low (UART1_BDL)

8

R/W

04h

40.2.2/751

4006_B002

UART Control Register 1 (UART1_C1)

8

R/W

00h

40.2.3/752

4006_B003

UART Control Register 2 (UART1_C2)

8

R/W

00h

40.2.4/753

4006_B004

UART Status Register 1 (UART1_S1)

8

R

C0h

40.2.5/755

4006_B005

UART Status Register 2 (UART1_S2)

8

R/W

00h

40.2.6/756

4006_B006

UART Control Register 3 (UART1_C3)

8

R/W

00h

40.2.7/758

4006_B007

UART Data Register (UART1_D)

8

R/W

00h

40.2.8/760

4006_B008

UART Control Register 4 (UART1_C4)

8

R/W

00h

40.2.9/760

4006_C000

UART Baud Rate Register: High (UART2_BDH)

8

R/W

00h

40.2.1/751

4006_C001

UART Baud Rate Register: Low (UART2_BDL)

8

R/W

04h

40.2.2/751

4006_C002

UART Control Register 1 (UART2_C1)

8

R/W

00h

40.2.3/752

4006_C003

UART Control Register 2 (UART2_C2)

8

R/W

00h

40.2.4/753

4006_C004

UART Status Register 1 (UART2_S1)

8

R

C0h

40.2.5/755

4006_C005

UART Status Register 2 (UART2_S2)

8

R/W

00h

40.2.6/756

4006_C006

UART Control Register 3 (UART2_C3)

8

R/W

00h

40.2.7/758

4006_C007

UART Data Register (UART2_D)

8

R/W

00h

40.2.8/760

4006_C008

UART Control Register 4 (UART2_C4)

8

R/W

00h

40.2.9/760

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Chapter 40 Universal Asynchronous Receiver/Transmitter (UART1 and UART2)

40.2.1 UART Baud Rate Register: High (UARTx_BDH)
This register, along with UART_BDL, controls the prescale divisor for UART baud rate
generation. To update the 13-bit baud rate setting [SBR12:SBR0], first write to
UART_BDH to buffer the high half of the new value and then write to UART_BDL. The
working value in UART_BDH does not change until UART_BDL is written.
Address: Base address + h offset
Bit

Read
Write
Reset

7

6

5

LBKDIE

RXEDGIE

SBNS

0

0

0

4

3

2

1

0

0

0

SBR
0

0

0

UARTx_BDH field descriptions
Field
7
LBKDIE

6
RXEDGIE

5
SBNS

Description
LIN Break Detect Interrupt Enable (for LBKDIF)
0
1

RxD Input Active Edge Interrupt Enable (for RXEDGIF)
0
1

Hardware interrupts from UART_S2[RXEDGIF] disabled (use polling).
Hardware interrupt requested when UART_S2[RXEDGIF] flag is 1.

Stop Bit Number Select
SBNS determines whether data characters are one or two stop bits.
0
1

4–0
SBR

Hardware interrupts from UART_S2[LBKDIF] disabled (use polling).
Hardware interrupt requested when UART_S2[LBKDIF] flag is 1.

One stop bit.
Two stop bit.

Baud Rate Modulo Divisor.
The 13 bits in SBR[12:0] are referred to collectively as BR, and they set the modulo divide rate for the
UART baud rate generator. When BR is cleared, the UART baud rate generator is disabled to reduce
supply current. When BR is 1 - 8191, the UART baud rate equals BUSCLK/(16×BR).

40.2.2 UART Baud Rate Register: Low (UARTx_BDL)
This register, along with UART_BDH, control the prescale divisor for UART baud rate
generation. To update the 13-bit baud rate setting [SBR12:SBR0], first write to
UART_BDH to buffer the high half of the new value and then write to UART_BDL. The
working value in UART_BDH does not change until UART_BDL is written.

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Register definition

UART_BDL is reset to a non-zero value, so after reset the baud rate generator remains
disabled until the first time the receiver or transmitter is enabled; that is, UART_C2[RE]
or UART_C2[TE] bits are written to 1.
Address: Base address + h offset
Bit

Read
Write
Reset

7

6

5

4

3

2

1

0

0

1

0

0

SBR
0

0

0

0

UARTx_BDL field descriptions
Field
7–0
SBR

Description
Baud Rate Modulo Divisor
These 13 bits in SBR[12:0] are referred to collectively as BR. They set the modulo divide rate for the
UART baud rate generator. When BR is cleared, the UART baud rate generator is disabled to reduce
supply current. When BR is 1 - 8191, the UART baud rate equals BUSCLK/(16×BR).

40.2.3 UART Control Register 1 (UARTx_C1)
This read/write register controls various optional features of the UART system.
Address: Base address + h offset
Bit

Read
Write
Reset

7

6

5

4

3

2

1

0

LOOPS

UARTSWAI

RSRC

M

WAKE

ILT

PE

PT

0

0

0

0

0

0

0

0

UARTx_C1 field descriptions
Field
7
LOOPS

Description
Loop Mode Select
Selects between loop back modes and normal 2-pin full-duplex modes. When LOOPS is set, the
transmitter output is internally connected to the receiver input.
0
1

6
UARTSWAI

UART Stops in Wait Mode
0
1

5
RSRC

Normal operation - RxD and TxD use separate pins.
Loop mode or single-wire mode where transmitter outputs are internally connected to receiver input.
(See RSRC bit.) RxD pin is not used by UART.

UART clocks continue to run in wait mode so the UART can be the source of an interrupt that wakes
up the CPU.
UART clocks freeze while CPU is in wait mode.

Receiver Source Select
Table continues on the next page...

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Chapter 40 Universal Asynchronous Receiver/Transmitter (UART1 and UART2)

UARTx_C1 field descriptions (continued)
Field

Description
This bit has no meaning or effect unless the LOOPS bit is set to 1. When LOOPS is set, the receiver input
is internally connected to the TxD pin and RSRC determines whether this connection is also connected to
the transmitter output.
0
1

4
M

Provided LOOPS is set, RSRC is cleared, selects internal loop back mode and the UART does not
use the RxD pins.
Single-wire UART mode where the TxD pin is connected to the transmitter output and receiver input.

9-Bit or 8-Bit Mode Select
0
1

3
WAKE

2
ILT

Receiver Wakeup Method Select
0
1

Idle-line wakeup.
Address-mark wakeup.

Idle Line Type Select
Setting this bit to 1 ensures that the stop bits and logic 1 bits at the end of a character do not count toward
the 10 or 11 bit times of logic high level needed by the idle line detection logic.
0
1

1
PE

Normal - start + 8 data bits (lsb first) + stop.
Receiver and transmitter use 9-bit data characters start + 8 data bits (lsb first) + 9th data bit + stop.

Idle character bit count starts after start bit.
Idle character bit count starts after stop bit.

Parity Enable
Enables hardware parity generation and checking. When parity is enabled, the most significant bit (msb) of
the data character, eighth or ninth data bit, is treated as the parity bit.
0
1

0
PT

No hardware parity generation or checking.
Parity enabled.

Parity Type
Provided parity is enabled (PE = 1), this bit selects even or odd parity. Odd parity means the total number
of 1s in the data character, including the parity bit, is odd. Even parity means the total number of 1s in the
data character, including the parity bit, is even.
0
1

Even parity.
Odd parity.

40.2.4 UART Control Register 2 (UARTx_C2)
This register can be read or written at any time.
Address: Base address + h offset
Bit

Read
Write
Reset

7

6

5

4

3

2

1

0

TIE

TCIE

RIE

ILIE

TE

RE

RWU

SBK

0

0

0

0

0

0

0

0

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Register definition

UARTx_C2 field descriptions
Field
7
TIE

6
TCIE

Description
Transmit Interrupt Enable for TDRE
0
1

Hardware interrupts from TDRE disabled; use polling.
Hardware interrupt requested when TDRE flag is 1.

Transmission Complete Interrupt Enable for TC
0
1

Hardware interrupts from TC disabled; use polling.
Hardware interrupt requested when TC flag is 1.

5
RIE

Receiver Interrupt Enable for RDRF

4
ILIE

Idle Line Interrupt Enable for IDLE

3
TE

Transmitter Enable

0
1

0
1

Hardware interrupts from RDRF disabled; use polling.
Hardware interrupt requested when RDRF flag is 1.

Hardware interrupts from IDLE disabled; use polling.
Hardware interrupt requested when IDLE flag is 1.

TE must be 1 to use the UART transmitter. When TE is set, the UART forces the TxD pin to act as an
output for the UART system.
When the UART is configured for single-wire operation (LOOPS = RSRC = 1), TXDIR controls the
direction of traffic on the single UART communication line (TxD pin).
TE can also queue an idle character by clearing TE then setting TE while a transmission is in progress.
When TE is written to 0, the transmitter keeps control of the port TxD pin until any data, queued idle, or
queued break character finishes transmitting before allowing the pin to revert to a general-purpose I/O pin.
0
1

2
RE

Receiver Enable
When the UART receiver is off, the RxD pin reverts to being a general-purpose port I/O pin. If LOOPS is
set the RxD pin reverts to being a general-purpose I/O pin even if RE is set.
0
1

1
RWU

Receiver off.
Receiver on.

Receiver Wakeup Control
This bit can be written to 1 to place the UART receiver in a standby state where it waits for automatic
hardware detection of a selected wakeup condition. The wakeup condition is an idle line between
messages, WAKE = 0, idle-line wakeup, or a logic 1 in the most significant data bit in a character, WAKE =
1, address-mark wakeup. Application software sets RWU and, normally, a selected hardware condition
automatically clears RWU.
0
1

0
SBK

Transmitter off.
Transmitter on.

Normal UART receiver operation.
UART receiver in standby waiting for wakeup condition.

Send Break
Writing a 1 and then a 0 to SBK queues a break character in the transmit data stream. Additional break
characters of 10 or 11 or 12, 13 or 14 or 15 if BRK13 = 1, bit times of logic 0 are queued as long as SBK is
set. Depending on the timing of the set and clear of SBK relative to the information currently being
transmitted, a second break character may be queued before software clears SBK.
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UARTx_C2 field descriptions (continued)
Field

Description
0
1

Normal transmitter operation.
Queue break character(s) to be sent.

40.2.5 UART Status Register 1 (UARTx_S1)
This register has eight read-only status flags. Writes have no effect. Special software
sequences, which do not involve writing to this register, clear these status flags.
Address: Base address + h offset
Bit

Read

7

6

5

4

3

2

1

0

TDRE

TC

RDRF

IDLE

OR

NF

FE

PF

1

1

0

0

0

0

0

0

Write
Reset

UARTx_S1 field descriptions
Field
7
TDRE

Description
Transmit Data Register Empty Flag
TDRE is set out of reset and when a transmit data value transfers from the transmit data buffer to the
transmit shifter, leaving room for a new character in the buffer. To clear TDRE, read UART_S1 with TDRE
set and then write to the UART data register (UART_D).
0
1

6
TC

Transmission Complete Flag
TC is set out of reset and when TDRE is set and no data, preamble, or break character is being
transmitted.
TC is cleared automatically by reading UART_S1 with TC set and then doing one of the following:
• Write to the UART data register (UART_D) to transmit new data
• Queue a preamble by changing TE from 0 to 1
• Queue a break character by writing 1 to UART_C2[SBK]
0
1

5
RDRF

Transmitter active (sending data, a preamble, or a break).
Transmitter idle (transmission activity complete).

Receive Data Register Full Flag
RDRF becomes set when a character transfers from the receive shifter into the receive data register
(UART_D). To clear RDRF, read UART_S1 with RDRF set and then read the UART data register
(UART_D).
0
1

4
IDLE

Transmit data register (buffer) full.
Transmit data register (buffer) empty.

Receive data register empty.
Receive data register full.

Idle Line Flag
IDLE is set when the UART receive line becomes idle for a full character time after a period of activity.
When ILT is cleared, the receiver starts counting idle bit times after the start bit. If the receive character is
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UARTx_S1 field descriptions (continued)
Field

Description
all 1s, these bit times and the stop bits time count toward the full character time of logic high, 10 or 11 bit
times depending on the M control bit, needed for the receiver to detect an idle line. When ILT is set, the
receiver doesn't start counting idle bit times until after the stop bits. The stop bits and any logic high bit
times at the end of the previous character do not count toward the full character time of logic high needed
for the receiver to detect an idle line.
To clear IDLE, read UART_S1 with IDLE set and then read the UART data register (UART_D). After IDLE
has been cleared, it cannot become set again until after a new character has been received and RDRF
has been set. IDLE is set only once even if the receive line remains idle for an extended period.
0
1

3
OR

Receiver Overrun Flag
OR is set when a new serial character is ready to be transferred to the receive data register (buffer), but
the previously received character has not been read from UART_D yet. In this case, the new character,
and all associated error information, is lost because there is no room to move it into UART_D. To clear
OR, read UART_S1 with OR set and then read the UART data register (UART_D).
0
1

2
NF

The advanced sampling technique used in the receiver takes seven samples during the start bit and three
samples in each data bit and the stop bits. If any of these samples disagrees with the rest of the samples
within any bit time in the frame, the flag NF is set at the same time as RDRF is set for the character. To
clear NF, read UART_S1 and then read the UART data register (UART_D).
No noise detected.
Noise detected in the received character in UART_D.

Framing Error Flag
FE is set at the same time as RDRF when the receiver detects a logic 0 where the stop bits was expected.
This suggests the receiver was not properly aligned to a character frame. To clear FE, read UART_S1
with FE set and then read the UART data register (UART_D).
0
1

0
PF

No overrun.
Receive overrun (new UART data lost).

Noise Flag

0
1
1
FE

No idle line detected.
Idle line was detected.

No framing error detected. This does not guarantee the framing is correct.
Framing error.

Parity Error Flag
PF is set at the same time as RDRF when parity is enabled (PE = 1) and the parity bit in the received
character does not agree with the expected parity value. To clear PF, read UART_S1 and then read the
UART data register (UART_D).
0
1

No parity error.
Parity error.

40.2.6 UART Status Register 2 (UARTx_S2)
This register contains one read-only status flag.

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When using an internal oscillator in a LIN system, it is necessary to raise the break
detection threshold one bit time. Under the worst case timing conditions allowed in LIN,
it is possible that a 0x00 data character can appear to be 10.26 bit times long at a slave
running 14% faster than the master. This would trigger normal break detection circuitry
designed to detect a 10-bit break symbol. When the LBKDE bit is set, framing errors are
inhibited and the break detection threshold changes from 10 bits to 11 bits, preventing
false detection of a 0x00 data character as a LIN break symbol.
Address: Base address + h offset
Bit

Read
Write
Reset

7

6

LBKDIF

RXEDGIF

0

0

5

0

0

4

3

2

1

RXINV

RWUID

BRK13

LBKDE

0

0

0

0

0

RAF

0

UARTx_S2 field descriptions
Field
7
LBKDIF

Description
LIN Break Detect Interrupt Flag
LBKDIF is set when the LIN break detect circuitry is enabled and a LIN break character is detected.
LBKDIF is cleared by writing a 1 to it.
0
1

6
RXEDGIF

RxD Pin Active Edge Interrupt Flag
RXEDGIF is set when an active edge, falling if RXINV = 0, rising if RXINV=1, on the RxD pin occurs.
RXEDGIF is cleared by writing a 1 to it.
0
1

5
Reserved
4
RXINV

No LIN break character has been detected.
LIN break character has been detected.

No active edge on the receive pin has occurred.
An active edge on the receive pin has occurred.

This field is reserved.
This read-only field is reserved and always has the value 0.
Receive Data Inversion
Setting this bit reverses the polarity of the received data input.
NOTE: Setting RXINV inverts the RxD input for all cases: data bits, start and stop bits, break, and idle.
0
1

3
RWUID

Receive Wake Up Idle Detect
RWUID controls whether the idle character that wakes up the receiver sets the IDLE bit.
0
1

2
BRK13

Receive data not inverted.
Receive data inverted.

During receive standby state (RWU = 1), the IDLE bit does not get set upon detection of an idle
character.
During receive standby state (RWU = 1), the IDLE bit gets set upon detection of an idle character.

Break Character Generation Length
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UARTx_S2 field descriptions (continued)
Field

Description
BRK13 selects a longer transmitted break character length. Detection of a framing error is not affected by
the state of this bit.
0
1

1
LBKDE

LIN Break Detection Enable
LBKDE selects a longer break character detection length. While LBKDE is set, framing error (FE) and
receive data register full (RDRF) flags are prevented from setting.
0
1

0
RAF

Break character is transmitted with length of 10 bit times (if M = 0, SBNS = 0) or 11 (if M = 1, SBNS =
0 or M = 0, SBNS = 1) or 12 (if M = 1, SBNS = 1).
Break character is transmitted with length of 13 bit times (if M = 0, SBNS = 0) or 14 (if M = 1, SBNS =
0 or M = 0, SBNS = 1) or 15 (if M = 1, SBNS = 1).

Break character is detected at length 10 bit times (if M = 0, SBNS = 0) or 11 (if M = 1, SBNS = 0 or M
= 0, SBNS = 1) or 12 (if M = 1, SBNS = 1).
Break character is detected at length of 11 bit times (if M = 0, SBNS = 0) or 12 (if M = 1, SBNS = 0 or
M = 0, SBNS = 1) or 13 (if M = 1, SBNS = 1).

Receiver Active Flag
RAF is set when the UART receiver detects the beginning of a valid start bit, and RAF is cleared
automatically when the receiver detects an idle line. This status flag can be used to check whether an
UART character is being received before instructing the MCU to go to stop mode.
0
1

UART receiver idle waiting for a start bit.
UART receiver active (RxD input not idle).

40.2.7 UART Control Register 3 (UARTx_C3)
Address: Base address + h offset
Bit

Read

7

R8

Write
Reset

0

6

5

4

3

2

1

0

T8

TXDIR

TXINV

ORIE

NEIE

FEIE

PEIE

0

0

0

0

0

0

0

UARTx_C3 field descriptions
Field

Description

7
R8

Ninth Data Bit for Receiver

6
T8

Ninth Data Bit for Transmitter

When the UART is configured for 9-bit data (M = 1), R8 can be thought of as a ninth receive data bit to the
left of the msb of the buffered data in the UART_D register. When reading 9-bit data, read R8 before
reading UART_D because reading UART_D completes automatic flag clearing sequences that could allow
R8 and UART_D to be overwritten with new data.

When the UART is configured for 9-bit data (M = 1), T8 may be thought of as a ninth transmit data bit to
the left of the msb of the data in the UART_D register. When writing 9-bit data, the entire 9-bit value is
transferred to the UART shift register after UART_D is written so T8 should be written, if it needs to
change from its previous value, before UART_D is written. If T8 does not need to change in the new value,
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UARTx_C3 field descriptions (continued)
Field

Description
such as when it is used to generate mark or space parity, it need not be written each time UART_D is
written.

5
TXDIR

TxD Pin Direction in Single-Wire Mode
When the UART is configured for single-wire half-duplex operation (LOOPS = RSRC = 1), this bit
determines the direction of data at the TxD pin.
0
1

4
TXINV

TxD pin is an input in single-wire mode.
TxD pin is an output in single-wire mode.

Transmit Data Inversion
Setting this bit reverses the polarity of the transmitted data output.
NOTE: Setting TXINV inverts the TxD output for all cases: data bits, start and stop bits, break, and idle.
0
1

3
ORIE

Overrun Interrupt Enable
This bit enables the overrun flag (OR) to generate hardware interrupt requests.
0
1

2
NEIE

This bit enables the noise flag (NF) to generate hardware interrupt requests.
NF interrupts disabled; use polling).
Hardware interrupt requested when NF is set.

Framing Error Interrupt Enable
This bit enables the framing error flag (FE) to generate hardware interrupt requests.
0
1

0
PEIE

OR interrupts disabled; use polling.
Hardware interrupt requested when OR is set.

Noise Error Interrupt Enable

0
1
1
FEIE

Transmit data not inverted.
Transmit data inverted.

FE interrupts disabled; use polling).
Hardware interrupt requested when FE is set.

Parity Error Interrupt Enable
This bit enables the parity error flag (PF) to generate hardware interrupt requests.
0
1

PF interrupts disabled; use polling).
Hardware interrupt requested when PF is set.

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40.2.8 UART Data Register (UARTx_D)
This register is actually two separate registers. Reads return the contents of the read-only
receive data buffer and writes go to the write-only transmit data buffer. Reads and writes
of this register are also involved in the automatic flag clearing mechanisms for the UART
status flags.
Address: Base address + h offset
Bit

Read
Write
Reset

7

6

5

4

3

2

1

0

R7T7

R6T6

R5T5

R4T4

R3T3

R2T2

R1T1

R0T0

0

0

0

0

0

0

0

0

2

1

0

UARTx_D field descriptions
Field

Description

7
R7T7

Read receive data buffer 7 or write transmit data buffer 7.

6
R6T6

Read receive data buffer 6 or write transmit data buffer 6.

5
R5T5

Read receive data buffer 5 or write transmit data buffer 5.

4
R4T4

Read receive data buffer 4 or write transmit data buffer 4.

3
R3T3

Read receive data buffer 3 or write transmit data buffer 3.

2
R2T2

Read receive data buffer 2 or write transmit data buffer 2.

1
R1T1

Read receive data buffer 1 or write transmit data buffer 1.

0
R0T0

Read receive data buffer 0 or write transmit data buffer 0.

40.2.9 UART Control Register 4 (UARTx_C4)
Address: Base address + h offset
Bit

Read
Write
Reset

7

6

5

4

3

TDMAS

0

RDMAS

0

0

0

0

0

0

0

0
0

0

0

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UARTx_C4 field descriptions
Field
7
TDMAS

Description
Transmitter DMA Select
TDMAS configures the transmit data register empty flag, TDRE, to generate interrupt or DMA requests if
TIE is set.
NOTE: If UART_C2[TIE] is cleared, TDRE DMA and TDRE interrupt request signals are not asserted
when the TDRE flag is set, regardless of the state of TDMAS.
If UART_C2[TIE] and TDMAS are both set, then UART_C2[TCIE] must be cleared, and UART_D
must not be written outside of servicing of a DMA request.
0
1

6
Reserved
5
RDMAS

If TIE is set and the TDRE flag is set, the TDRE interrupt request signal is asserted to request
interrupt service.
If TIE is set and the TDRE flag is set, the TDRE DMA request signal is asserted to request a DMA
transfer.

This field is reserved.
This read-only field is reserved and always has the value 0.
Receiver Full DMA Select
RDMAS configures the receiver data register full flag, RDRF, to generate interrupt or DMA requests if RIE
is set.
NOTE: If RIE is cleared, the RDRF DMA and RDRF interrupt request signals are not asserted when the
RDRF flag is set, regardless of the state of RDMAS.
0
1

If RIE is set and the RDRF flag is set, the RDRF interrupt request signal is asserted to request
interrupt service.
If RIE is set and the RDRF flag is set, the RDRF DMA request signal is asserted to request a DMA
transfer.

4
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

3
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

2–0
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

40.3 Functional description
The UART allows full-duplex, asynchronous, NRZ serial communication among the
MCU and remote devices, including other MCUs. The UART comprises a baud rate
generator, transmitter, and receiver block. The transmitter and receiver operate
independently, although they use the same baud rate generator. During normal operation,
the MCU monitors the status of the UART, writes the data to be transmitted, and
processes received data. The following describes each of the blocks of the UART.

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40.3.1 Baud rate generation
As shown in the following figure, the clock source for the UART baud rate generator is
the bus-rate clock.
Modulo Divide By
(1 through 8191)

UART Module Clock

SBR[12:0]

Divide By
16

Tx Baud Rate

Rx Sampling Clock
(16 × Baud Rate)

Baud Rate Generator
Off If [SBR12:SBR0] = 0
Baud Rate =

UART Module Clock
SBR[12:0] × 16

Figure 40-30. UART baud rate generation

UART communications require the transmitter and receiver, which typically derive baud
rates from independent clock sources, to use the same baud rate. Allowed tolerance on
this baud frequency depends on the details of how the receiver synchronizes to the
leading edge of the start bit and how bit sampling is performed.
The MCU resynchronizes to bit boundaries on every high-to-low transition. In the worst
case, there are no such transitions in the full 10- or 11-bit or 12-bittime character frame
so any mismatch in baud rate is accumulated for the whole character time. For a
Freescale UART system whose bus frequency is driven by a crystal, the allowed baud
rate mismatch is about ±4.5 percent for 8-bit data format and about ±4 percent for 9-bit
data format. Although baud rate modulo divider settings do not always produce baud
rates that exactly match standard rates, it is normally possible to get within a few percent,
which is acceptable for reliable communications.

40.3.2 Transmitter functional description
This section describes the overall block diagram for the UART transmitter, as well as
specialized functions for sending break and idle characters.
The transmitter output (TxD) idle state defaults to logic high, UART_C3[TXINV] is
cleared following reset. The transmitter output is inverted by setting UART_C3[TXINV].
The transmitter is enabled by setting the TE bit in UARTxC2. This queues a preamble
character that is one full character frame of the idle state. The transmitter then remains
idle until data is available in the transmit data buffer. Programs store data into the
transmit data buffer by writing to the UART data register (UART_D).
The central element of the UART transmitter is the transmit shift register that is 10 or 11
or 12 bits long depending on the setting in the UART_C1[M] control bit and
UART_BDH[SBNS] bit. For the remainder of this section, assume UART_C1[M] is
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Chapter 40 Universal Asynchronous Receiver/Transmitter (UART1 and UART2)

cleared, UART_BDH[SBNS] is also cleared, selecting the normal 8-bit data mode. In 8bit data mode, the shift register holds a start bit, eight data bits, and a stop bit. When the
transmit shift register is available for a new UART character, the value waiting in the
transmit data register is transferred to the shift register, synchronized with the baud rate
clock, and the transmit data register empty (UART_S1[TDRE]) status flag is set to
indicate another character may be written to the transmit data buffer at UART_D.
If no new character is waiting in the transmit data buffer after a stop bit is shifted out the
TxD pin, the transmitter sets the transmit complete flag and enters an idle mode, with
TxD high, waiting for more characters to transmit.
Writing 0 to UART_C2[TE] does not immediately release the pin to be a general-purpose
I/O pin. Any transmit activity in progress must first be completed. This includes data
characters in progress, queued idle characters, and queued break characters.

40.3.2.1 Send break and queued idle
The UART_C2[SBK] bit sends break characters originally used to gain the attention of
old teletype receivers. Break characters are a full character time of logic 0, 10 bit times
including the start and stop bits. A longer break of 13 bit times can be enabled by setting
UART_S2[BRK13]. Normally, a program would wait for UART_S1[TDRE] to become
set to indicate the last character of a message has moved to the transmit shifter, write 1,
and then write 0 to the UART_C2[SBK] bit. This action queues a break character to be
sent as soon as the shifter is available. If UART_C2[SBK] remains 1 when the queued
break moves into the shifter, synchronized to the baud rate clock, an additional break
character is queued. If the receiving device is another Freescale Semiconductor UART,
the break characters are received as 0s in all eight data bits and a framing error
(UART_S1[FE] = 1) occurs.
When idle-line wakeup is used, a full character time of idle (logic 1) is needed between
messages to wake up any sleeping receivers. Normally, a program would wait for
UART_S1[TDRE] to become set to indicate the last character of a message has moved to
the transmit shifter, then write 0 and then write 1 to the UART_C2[TE] bit. This action
queues an idle character to be sent as soon as the shifter is available. As long as the
character in the shifter does not finish while UART_C2[TE] is cleared, the UART
transmitter never actually releases control of the TxD pin. If there is a possibility of the
shifter finishing while UART_C2[TE] is cleared, set the general-purpose I/O controls so
the pin shared with TxD is an output driving a logic 1. This ensures that the TxD line
looks like a normal idle line even if the UART loses control of the port pin between
writing 0 and then 1 to UART_C2[TE].

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The length of the break character is affected by the UART_S2[BRK13] and
UART_C1[M] bits as shown below.
Table 40-31. Break character length
BRK13

M

SBNS

Break character length

0

0

0

10 bit times

0

0

1

11 bit times

0

1

0

11 bit times

0

1

1

12 bit times

1

0

0

13 bit times

1

0

1

14 bit times

1

1

0

14 bit times

1

1

1

15 bit times

40.3.3 Receiver functional description
In this section, the receiver block diagram is a guide for the overall receiver functional
description. Next, the data sampling technique used to reconstruct receiver data is
described in more detail. Finally, two variations of the receiver wakeup function are
explained.
The receiver input is inverted by setting UART_S2[RXINV]. The receiver is enabled by
setting the UART_C2[RE] bit. Character frames consist of a start bit of logic 0, eight (or
nine) data bits (lsb first), and one (or two) stop bits of logic 1. For information about 9-bit
data mode, refer to 8- and 9-bit data modes. For the remainder of this discussion, assume
the UART is configured for normal 8-bit data mode.
After receiving the stop bit into the receive shifter, and provided the receive data register
is not already full, the data character is transferred to the receive data register and the
receive data register full (UART_S1[RDRF]) status flag is set. If UART_S1[RDRF] was
already set indicating the receive data register (buffer) was already full, the overrun (OR)
status flag is set and the new data is lost. Because the UART receiver is double-buffered,
the program has one full character time after UART_S1[RDRF] is set before the data in
the receive data buffer must be read to avoid a receiver overrun.
When a program detects that the receive data register is full (UART_S1[RDRF] = 1), it
gets the data from the receive data register by reading UART_D. The UART_S1[RDRF]
flag is cleared automatically by a two-step sequence normally satisfied in the course of
the user's program that manages receive data. Refer to Interrupts and status flags for more
details about flag clearing.

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40.3.3.1 Data sampling technique
The UART receiver uses a 16× baud rate clock for sampling. The receiver starts by
taking logic level samples at 16 times the baud rate to search for a falling edge on the
RxD serial data input pin. A falling edge is defined as a logic 0 sample after three
consecutive logic 1 samples. The 16× baud rate clock divides the bit time into 16
segments labeled UART_D[[RT1] through UART_D[RT16]. When a falling edge is
located, three more samples are taken at UART_D[RT3], UART_D[RT5], and
UART_D[RT7] to make sure this was a real start bit and not merely noise. If at least two
of these three samples are 0, the receiver assumes it is synchronized to a receive
character.
The receiver then samples each bit time, including the start and stop bits, at
UART_D[RT8], UART_D[RT9], and UART_D[RT10] to determine the logic level for
that bit. The logic level is interpreted to be that of the majority of the samples taken
during the bit time. In the case of the start bit, the bit is assumed to be 0 if at least two of
the samples at UART_D[RT3], UART_D[RT5], and UART_D[RT7] are 0 even if one or
all of the samples taken at UART_D[RT8], UART_D[RT9], and UART_D[RT10] are 1s.
If any sample in any bit time, including the start and stop bits, in a character frame fails to
agree with the logic level for that bit, the noise flag (UART_S1[NF]) is set when the
received character is transferred to the receive data buffer.
The falling edge detection logic continuously looks for falling edges. If an edge is
detected, the sample clock is resynchronized to bit times. This improves the reliability of
the receiver in the presence of noise or mismatched baud rates. It does not improve worst
case analysis because some characters do not have any extra falling edges anywhere in
the character frame.
In the case of a framing error, provided the received character was not a break character,
the sampling logic that searches for a falling edge is filled with three logic 1 samples so
that a new start bit can be detected almost immediately.
In the case of a framing error, the receiver is inhibited from receiving any new characters
until the framing error flag is cleared. The receive shift register continues to function, but
a complete character cannot transfer to the receive data buffer if UART_S1[FE] remains
set.

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Functional description

40.3.3.2 Receiver wakeup operation
Receiver wakeup is a hardware mechanism that allows an UART receiver to ignore the
characters in a message intended for a different UART receiver. In such a system, all
receivers evaluate the first character(s) of each message, and as soon as they determine
the message is intended for a different receiver, they write logic 1 to the receiver wake up
control bit(UART_C2[RWU]). When RWU bit is set, the status flags associated with the
receiver, with the exception of the idle bit, IDLE, when UART_S2[RWUID] bit is set,
are inhibited from setting, thus eliminating the software overhead for handling the
unimportant message characters. At the end of a message, or at the beginning of the next
message, all receivers automatically force UART_C2[RWU] to 0 so all receivers wake
up in time to look at the first character(s) of the next message.
40.3.3.2.1

Idle-line wakeup

When wake is cleared, the receiver is configured for idle-line wakeup. In this mode,
UART_C2[RWU] is cleared automatically when the receiver detects a full character time
of the idle-line level. The UART_C1[M] control bit selects 8-bit or 9-bit data mode and
the UART_BDH[SBNS] bit selects 1-bit or 2-bit stop bit number that determines how
many bit times of idle are needed to constitute a full character time, 10 or 11 or 12 bit
times because of the start and stop bits.
When UARTI_C2[RWU] is one and UART_S2[RWUID] is zero, the idle condition that
wakes up the receiver does not set the UART_S1[IDLE] flag. The receiver wakes up and
waits for the first data character of the next message that sets the UART_S1[RDRF] flag
and generates an interrupt if enabled. When UART_S2[RWUID] is one, any idle
condition sets the UART_S1[IDLE] flag and generates an interrupt if enabled, regardless
of whether UART_C2[RWU] is zero or one.
The idle-line type (UART_C1[ILT]) control bit selects one of two ways to detect an idle
line. When UART_C1[ILT] is cleared, the idle bit counter starts after the start bit so the
stop bit and any logic 1s at the end of a character count toward the full character time of
idle. When UART_C1[ILT] is set, the idle bit counter does not start until after a stop bit
time, so the idle detection is not affected by the data in the last character of the previous
message.
40.3.3.2.2

Address-mark wakeup

When wake is set, the receiver is configured for address-mark wakeup. In this mode,
UART_C2[RWU] is cleared automatically when the receiver detects a, or two, if
UART_BDH[SBNS] = 1, logic 1 in the most significant bits of a received character,
eighth bit when UART_C1[M] is cleared and ninth bit when UART_C1[M] is set.
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Chapter 40 Universal Asynchronous Receiver/Transmitter (UART1 and UART2)

Address-mark wakeup allows messages to contain idle characters, but requires the msb
be reserved for use in address frames. The one, or two, if UART_BDH[SBNS] = 1, logic
1s msb of an address frame clears the UART_C2[RWU] bit before the stop bits are
received and sets the UART_S1[RDRF] flag. In this case, the character with the msb set
is received even though the receiver was sleeping during most of this character time.

40.3.4 Interrupts and status flags
The UART system has three separate interrupt vectors to reduce the amount of software
needed to isolate the cause of the interrupt. One interrupt vector is associated with the
transmitter for UART_S1[TDRE] and UART_S1[TC] events. Another interrupt vector is
associated with the receiver for RDRF, IDLE, RXEDGIF, and LBKDIF events. A third
vector is used for OR, NF, FE, and PF error conditions. Each of these ten interrupt
sources can be separately masked by local interrupt enable masks. The flags can be
polled by software when the local masks are cleared to disable generation of hardware
interrupt requests.
The UART transmitter has two status flags that can optionally generate hardware
interrupt requests. Transmit data register empty (UART_S1[TDRE]) indicates when there
is room in the transmit data buffer to write another transmit character to UART_D. If the
transmit interrupt enable (UART_C2[TIE]) bit is set, a hardware interrupt is requested
when UART_S1[TDRE] is set. Transmit complete (UART_S1[TC]) indicates that the
transmitter is finished transmitting all data, preamble, and break characters and is idle
with TxD at the inactive level. This flag is often used in systems with modems to
determine when it is safe to turn off the modem. If the transmit complete interrupt enable
(UART_C2[TCIE]) bit is set, a hardware interrupt is requested when UART_S1[TC] is
set. Instead of hardware interrupts, software polling may be used to monitor the
UART_S1[TDRE] and UART_S1[TC] status flags if the corresponding UART_C2[TIE]
or UART_C2[TCIE] local interrupt masks are cleared.
When a program detects that the receive data register is full (UART_S1[RDRF] = 1), it
gets the data from the receive data register by reading UART_D. The UART_S1[RDRF]
flag is cleared by reading UARTxS1 while UART_S1[RDRF] is set and then reading
UART_D.
When polling is used, this sequence is naturally satisfied in the normal course of the user
program. If hardware interrupts are used, UARTxS1 must be read in the interrupt service
routine (ISR). Normally, this is done in the ISR anyway to check for receive errors, so the
sequence is automatically satisfied.

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Functional description

The IDLE status flag includes logic that prevents it from getting set repeatedly when the
RxD line remains idle for an extended period of time. IDLE is cleared by reading
UARTxS1 while UART_S1[IDLE] is set and then reading UART_D. After
UART_S1[IDLE] has been cleared, it cannot become set again until the receiver has
received at least one new character and has set UART_S1[RDRF].
If the associated error was detected in the received character that caused
UART_S1[RDRF] to be set, the error flags - noise flag (UART_S1[NF]), framing error
(UART_S1[FE]), and parity error flag (UART_S1[PF]) - are set at the same time as
UART_S1[RDRF]. These flags are not set in overrun cases.
If UART_S1[RDRF] was already set when a new character is ready to be transferred
from the receive shifter to the receive data buffer, the overrun (UART_S1[OR]) flag is
set instead of the data along with any associated NF, FE, or PF condition is lost.
At any time, an active edge on the RxD serial data input pin causes the
UART_S2[RXEDGIF] flag to set. The UART_S2[RXEDGIF] flag is cleared by writing a
1 to it. This function depends on the receiver being enabled (UART_C2[RE] = 1).

40.3.5 DMA Operation
In the transmitter, flags TDRE and TC can be configured to assert a DMA transfer
request. In the receiver, flags RDRF, IDLE and LBKDIF can be configured to assert a
DMA transfer request. The following table shows the configuration bit settings required
to configure each flag for DMA operation.
Table 40-32. DMA configuration
Flag

Request enable bit

DMA select bit

TDRE

TIE = 1

TDMAS = 1

TC

TCIE = 1

TCDMAS = 1

RDRF

RIE = 1

RDMAS = 1

IDLE

ILIE = 1

ILDMAS = 1

LBKDIF

LBKDIE = 1

LBKDDMAS = 1

When a flag is configured for a DMA request, its associated DMA request is asserted
when the flag is set. When the RDRF or IDLE flag is configured as a DMA request, the
clearing mechanism of reading UART_S1 followed by reading UART_D does not clear
the associated flag.The DMA request remains asserted until an indication is received that
the DMA transactions are done. When this indication is received, the flag bit and the
associated DMA request are cleared. If the DMA operation failed to remove the situation
that caused the DMA request another request will be issued.
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Chapter 40 Universal Asynchronous Receiver/Transmitter (UART1 and UART2)

40.3.6 Additional UART functions
The following sections describe additional UART functions.

40.3.6.1 8- and 9-bit data modes
The UART system, transmitter and receiver, can be configured to operate in 9-bit data
mode by setting the UART_C1[M]. In 9-bit mode, there is a ninth data bit to the left of
the msb of the UART data register. For the transmit data buffer, this bit is stored in T8 in
UART_C3. For the receiver, the ninth bit is held in UART_C3[R8].
For coherent writes to the transmit data buffer, write to the UART_C3[T8] bit before
writing to UART_D.
If the bit value to be transmitted as the ninth bit of a new character is the same as for the
previous character, it is not necessary to write to UART_C3[T8] again. When data is
transferred from the transmit data buffer to the transmit shifter, the value in
UART_C3[T8] is copied at the same time data is transferred from UART_D to the
shifter.
The 9-bit data mode is typically used with parity to allow eight bits of data plus the parity
in the ninth bit, or it is used with address-mark wakeup so the ninth data bit can serve as
the wakeup bit. In custom protocols, the ninth bit can also serve as a software-controlled
marker.

40.3.6.2 Stop mode operation
During all stop modes, clocks to the UART module are halted.
No UART module registers are affected in stop3 mode.
Because the clocks are halted, the UART module resumes operation upon exit from stop,
only in stop and VLPS mode. Software must ensure stop mode is not entered while there
is a character being transmitted out of or received into the UART module.

40.3.6.3 Loop mode
When UART_C1[LOOPS] is set, the UART_C1[RSRC] bit in the same register chooses
between loop mode (UART_C1[RSRC] = 0) or single-wire mode (UART_C1[RSRC] =
1). Loop mode is sometimes used to check software, independent of connections in the
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Functional description

external system, to help isolate system problems. In this mode, the transmitter output is
internally connected to the receiver input and the RxD pin is not used by the UART, so it
reverts to a general-purpose port I/O pin.

40.3.6.4 Single-wire operation
When UART_C1[LOOPS] is set, the RSRC bit in the same register chooses between
loop mode (UART_C1[RSRC] = 0) or single-wire mode (UART_C1[RSRC] = 1).
Single-wire mode implements a half-duplex serial connection. The receiver is internally
connected to the transmitter output and to the TxD pin. The RxD pin is not used and
reverts to a general-purpose port I/O pin.
In single-wire mode, the UART_C3[TXDIR] bit controls the direction of serial data on
the TxD pin. When UART_C3[TXDIR] is cleared, the TxD pin is an input to the UART
receiver and the transmitter is temporarily disconnected from the TxD pin so an external
device can send serial data to the receiver. When UART_C3[TXDIR] is set, the TxD pin
is an output driven by the transmitter, the internal loop back connection is disabled, and
as a result the receiver can not receive characters that are sent out by the transmitter.

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Chapter 41
General-Purpose Input/Output (GPIO)
41.1 Introduction
NOTE
For the chip-specific implementation details of this module's
instances see the chip configuration information.
The general-purpose input and output (GPIO) module communicates to the processor
core via a zero wait state interface for maximum pin performance. The GPIO registers
support 8-bit, 16-bit or 32-bit accesses.
The GPIO data direction and output data registers control the direction and output data of
each pin when the pin is configured for the GPIO function. The GPIO input data register
displays the logic value on each pin when the pin is configured for any digital function,
provided the corresponding Port Control and Interrupt module for that pin is enabled.
Efficient bit manipulation of the general-purpose outputs is supported through the
addition of set, clear, and toggle write-only registers for each port output data register.

41.1.1 Features
• Features of the GPIO module include:
• Pin input data register visible in all digital pin-multiplexing modes
• Pin output data register with corresponding set/clear/toggle registers
• Pin data direction register
• Zero wait state access to GPIO registers through IOPORT
NOTE
GPIO module is clocked by system clock.

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Introduction

41.1.2 Modes of operation
The following table depicts different modes of operation and the behavior of the GPIO
module in these modes.
Table 41-1. Modes of operation
Modes of operation

Description

Run

The GPIO module operates normally.

Wait

The GPIO module operates normally.

Stop

The GPIO module is disabled.

Debug

The GPIO module operates normally.

41.1.3 GPIO signal descriptions
Table 41-2. GPIO signal descriptions
GPIO signal descriptions

Description

I/O

PORTA31–PORTA0

General-purpose input/output

I/O

PORTB31–PORTB0

General-purpose input/output

I/O

PORTC31–PORTC0

General-purpose input/output

I/O

PORTD31–PORTD0

General-purpose input/output

I/O

PORTE31–PORTE0

General-purpose input/output

I/O

NOTE
Not all pins within each port are implemented on each device.
See the chapter on signal multiplexing for the number of GPIO
ports available in the device.

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Chapter 41 General-Purpose Input/Output (GPIO)

41.1.3.1 Detailed signal description
Table 41-3. GPIO interface-detailed signal descriptions
Signal

I/O

Description

PORTA31–PORTA0

I/O

General-purpose input/output
State meaning

PORTB31–PORTB0

Asserted: The pin is logic 1.
Deasserted: The pin is logic 0.

PORTC31–PORTC0
Timing

PORTD31–PORTD0

Assertion: When output, this
signal occurs on the risingedge of the system clock. For
input, it may occur at any time
and input may be asserted
asynchronously to the system
clock.

PORTE31–PORTE0

Deassertion: When output,
this signal occurs on the
rising-edge of the system
clock. For input, it may occur
at any time and input may be
asserted asynchronously to
the system clock.

41.2 Memory map and register definition
Any read or write access to the GPIO memory space that is outside the valid memory
map results in a bus error.
NOTE
For simplicity, each GPIO port's registers appear with the same
width of 32 bits, corresponding to 32 pins. The actual number
of pins per port (and therefore the number of usable control bits
per port register) is chip-specific. Refer to the Chip
Configuration chapter to see the exact control bits for the nonidentical port instance.
GPIO memory map
Absolute
address
(hex)

Register name

Width
Access
(in bits)

400F_F000

Port Data Output Register (GPIOA_PDOR)

32

400F_F004

Port Set Output Register (GPIOA_PSOR)

32

Reset value

Section/
page

0000_0000h

41.2.1/775

W
(always 0000_0000h
reads 0)

41.2.2/776

R/W

Table continues on the next page...

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Memory map and register definition

GPIO memory map (continued)
Absolute
address
(hex)

Register name

Width
Access
(in bits)

Reset value

Section/
page

32

W
(always 0000_0000h
reads 0)

41.2.3/776

400F_F00C Port Toggle Output Register (GPIOA_PTOR)

32

W
(always 0000_0000h
reads 0)

41.2.4/777

400F_F010

Port Data Input Register (GPIOA_PDIR)

32

R

0000_0000h

41.2.5/777

400F_F014

Port Data Direction Register (GPIOA_PDDR)

32

R/W

0000_0000h

41.2.6/778

400F_F040

Port Data Output Register (GPIOB_PDOR)

32

R/W

0000_0000h

41.2.1/775

400F_F044

Port Set Output Register (GPIOB_PSOR)

32

W
(always 0000_0000h
reads 0)

41.2.2/776

400F_F048

Port Clear Output Register (GPIOB_PCOR)

32

W
(always 0000_0000h
reads 0)

41.2.3/776

400F_F04C Port Toggle Output Register (GPIOB_PTOR)

32

W
(always 0000_0000h
reads 0)

41.2.4/777

400F_F050

Port Data Input Register (GPIOB_PDIR)

32

R

0000_0000h

41.2.5/777

400F_F054

Port Data Direction Register (GPIOB_PDDR)

32

R/W

0000_0000h

41.2.6/778

400F_F080

Port Data Output Register (GPIOC_PDOR)

32

R/W

0000_0000h

41.2.1/775

400F_F084

Port Set Output Register (GPIOC_PSOR)

32

W
(always 0000_0000h
reads 0)

41.2.2/776

400F_F088

Port Clear Output Register (GPIOC_PCOR)

32

W
(always 0000_0000h
reads 0)

41.2.3/776

400F_F08C Port Toggle Output Register (GPIOC_PTOR)

32

W
(always 0000_0000h
reads 0)

41.2.4/777

400F_F090

Port Data Input Register (GPIOC_PDIR)

32

R

0000_0000h

41.2.5/777

400F_F094

Port Data Direction Register (GPIOC_PDDR)

32

R/W

0000_0000h

41.2.6/778

400F_F0C0 Port Data Output Register (GPIOD_PDOR)

32

R/W

0000_0000h

41.2.1/775

400F_F0C4 Port Set Output Register (GPIOD_PSOR)

32

W
(always 0000_0000h
reads 0)

41.2.2/776

400F_F0C8 Port Clear Output Register (GPIOD_PCOR)

32

W
(always 0000_0000h
reads 0)

41.2.3/776

400F_F0CC Port Toggle Output Register (GPIOD_PTOR)

32

W
(always 0000_0000h
reads 0)

41.2.4/777

400F_F0D0 Port Data Input Register (GPIOD_PDIR)

32

R

0000_0000h

41.2.5/777

400F_F0D4 Port Data Direction Register (GPIOD_PDDR)

32

R/W

0000_0000h

41.2.6/778

400F_F008

Port Clear Output Register (GPIOA_PCOR)

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Chapter 41 General-Purpose Input/Output (GPIO)

GPIO memory map (continued)
Absolute
address
(hex)

Width
Access
(in bits)

Register name

R/W

Reset value

Section/
page

0000_0000h

41.2.1/775

400F_F100

Port Data Output Register (GPIOE_PDOR)

32

400F_F104

Port Set Output Register (GPIOE_PSOR)

32

W
(always 0000_0000h
reads 0)

41.2.2/776

400F_F108

Port Clear Output Register (GPIOE_PCOR)

32

W
(always 0000_0000h
reads 0)

41.2.3/776

400F_F10C Port Toggle Output Register (GPIOE_PTOR)

32

W
(always 0000_0000h
reads 0)

41.2.4/777

400F_F110

Port Data Input Register (GPIOE_PDIR)

32

R

0000_0000h

41.2.5/777

400F_F114

Port Data Direction Register (GPIOE_PDDR)

32

R/W

0000_0000h

41.2.6/778

41.2.1 Port Data Output Register (GPIOx_PDOR)
This register configures the logic levels that are driven on each general-purpose output
pins.
NOTE
Do not modify pin configuration registers associated with pins
not available in your selected package. All un-bonded pins not
available in your package will default to DISABLE state for
lowest power consumption.
Address: Base address + 0h offset
Bit
R
W

31

Reset

0

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

PDO
0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

GPIOx_PDOR field descriptions
Field
31–0
PDO

Description
Port Data Output
Register bits for un-bonded pins return a undefined value when read.
0
1

Logic level 0 is driven on pin, provided pin is configured for general-purpose output.
Logic level 1 is driven on pin, provided pin is configured for general-purpose output.

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Memory map and register definition

41.2.2 Port Set Output Register (GPIOx_PSOR)
This register configures whether to set the fields of the PDOR.
Address: Base address + 4h offset
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

R

0

W

PTSO

Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

GPIOx_PSOR field descriptions
Field

Description

31–0
PTSO

Port Set Output
Writing to this register will update the contents of the corresponding bit in the PDOR as follows:
0
1

Corresponding bit in PDORn does not change.
Corresponding bit in PDORn is set to logic 1.

41.2.3 Port Clear Output Register (GPIOx_PCOR)
This register configures whether to clear the fields of PDOR.
Address: Base address + 8h offset
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

R

0

W

PTCO

Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

GPIOx_PCOR field descriptions
Field
31–0
PTCO

Description
Port Clear Output
Writing to this register will update the contents of the corresponding bit in the Port Data Output Register
(PDOR) as follows:
0
1

Corresponding bit in PDORn does not change.
Corresponding bit in PDORn is cleared to logic 0.

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Chapter 41 General-Purpose Input/Output (GPIO)

41.2.4 Port Toggle Output Register (GPIOx_PTOR)
Address: Base address + Ch offset
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

R

0

W

PTTO

Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

GPIOx_PTOR field descriptions
Field

Description

31–0
PTTO

Port Toggle Output
Writing to this register will update the contents of the corresponding bit in the PDOR as follows:
0
1

Corresponding bit in PDORn does not change.
Corresponding bit in PDORn is set to the inverse of its existing logic state.

41.2.5 Port Data Input Register (GPIOx_PDIR)
NOTE
Do not modify pin configuration registers associated with pins
not available in your selected package. All un-bonded pins not
available in your package will default to DISABLE state for
lowest power consumption.
Address: Base address + 10h offset
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

PDI

R
W
Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

GPIOx_PDIR field descriptions
Field
31–0
PDI

Description
Port Data Input
Reads 0 at the unimplemented pins for a particular device. Pins that are not configured for a digital
function read 0. If the Port Control and Interrupt module is disabled, then the corresponding bit in PDIR
does not update.
0
1

Pin logic level is logic 0, or is not configured for use by digital function.
Pin logic level is logic 1.

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FGPIO memory map and register definition

41.2.6 Port Data Direction Register (GPIOx_PDDR)
The PDDR configures the individual port pins for input or output.
Address: Base address + 14h offset
Bit
R
W

31

Reset

0

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

PDD
0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

GPIOx_PDDR field descriptions
Field
31–0
PDD

Description
Port Data Direction
Configures individual port pins for input or output.
0
1

Pin is configured as general-purpose input, for the GPIO function.
Pin is configured as general-purpose output, for the GPIO function.

41.3 FGPIO memory map and register definition
Any read or write access to the FGPIO memory space that is outside the valid memory
map results in a bus error. All register accesses complete with zero wait states, except
error accesses which complete with one wait state.
NOTE
For simplicity, each FGPIO port's registers appear with the
same width of 32 bits, corresponding to 32 pins. The actual
number of pins per port (and therefore the number of usable
control bits per port register) is chip-specific. Refer to the Chip
Configuration chapter to see the exact control bits for the nonidentical port instance.
FGPIO memory map
Absolute
address
(hex)

Register name

Width
Access
(in bits)

F80F_F000

Port Data Output Register (FGPIOA_PDOR)

32

F80F_F004

Port Set Output Register (FGPIOA_PSOR)

32

Reset value

Section/
page

0000_0000h

41.3.1/780

W
(always 0000_0000h
reads 0)

41.3.2/781

R/W

Table continues on the next page...

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Chapter 41 General-Purpose Input/Output (GPIO)

FGPIO memory map (continued)
Absolute
address
(hex)

Register name

Width
Access
(in bits)

Reset value

Section/
page

32

W
(always 0000_0000h
reads 0)

41.3.3/781

F80F_F00C Port Toggle Output Register (FGPIOA_PTOR)

32

W
(always 0000_0000h
reads 0)

41.3.4/782

F80F_F010

Port Data Input Register (FGPIOA_PDIR)

32

R

0000_0000h

41.3.5/782

F80F_F014

Port Data Direction Register (FGPIOA_PDDR)

32

R/W

0000_0000h

41.3.6/783

F80F_F040

Port Data Output Register (FGPIOB_PDOR)

32

R/W

0000_0000h

41.3.1/780

F80F_F044

Port Set Output Register (FGPIOB_PSOR)

32

W
(always 0000_0000h
reads 0)

41.3.2/781

F80F_F048

Port Clear Output Register (FGPIOB_PCOR)

32

W
(always 0000_0000h
reads 0)

41.3.3/781

F80F_F04C Port Toggle Output Register (FGPIOB_PTOR)

32

W
(always 0000_0000h
reads 0)

41.3.4/782

F80F_F050

Port Data Input Register (FGPIOB_PDIR)

32

R

0000_0000h

41.3.5/782

F80F_F054

Port Data Direction Register (FGPIOB_PDDR)

32

R/W

0000_0000h

41.3.6/783

F80F_F080

Port Data Output Register (FGPIOC_PDOR)

32

R/W

0000_0000h

41.3.1/780

F80F_F084

Port Set Output Register (FGPIOC_PSOR)

32

W
(always 0000_0000h
reads 0)

41.3.2/781

F80F_F088

Port Clear Output Register (FGPIOC_PCOR)

32

W
(always 0000_0000h
reads 0)

41.3.3/781

F80F_F08C Port Toggle Output Register (FGPIOC_PTOR)

32

W
(always 0000_0000h
reads 0)

41.3.4/782

F80F_F090

Port Data Input Register (FGPIOC_PDIR)

32

R

0000_0000h

41.3.5/782

F80F_F094

Port Data Direction Register (FGPIOC_PDDR)

32

R/W

0000_0000h

41.3.6/783

F80F_F0C0 Port Data Output Register (FGPIOD_PDOR)

32

R/W

0000_0000h

41.3.1/780

F80F_F0C4 Port Set Output Register (FGPIOD_PSOR)

32

W
(always 0000_0000h
reads 0)

41.3.2/781

F80F_F0C8 Port Clear Output Register (FGPIOD_PCOR)

32

W
(always 0000_0000h
reads 0)

41.3.3/781

F80F_F0CC Port Toggle Output Register (FGPIOD_PTOR)

32

W
(always 0000_0000h
reads 0)

41.3.4/782

F80F_F0D0 Port Data Input Register (FGPIOD_PDIR)

32

R

0000_0000h

41.3.5/782

F80F_F0D4 Port Data Direction Register (FGPIOD_PDDR)

32

R/W

0000_0000h

41.3.6/783

F80F_F008

Port Clear Output Register (FGPIOA_PCOR)

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FGPIO memory map and register definition

FGPIO memory map (continued)
Absolute
address
(hex)

Width
Access
(in bits)

Register name

R/W

Reset value

Section/
page

0000_0000h

41.3.1/780

F80F_F100

Port Data Output Register (FGPIOE_PDOR)

32

F80F_F104

Port Set Output Register (FGPIOE_PSOR)

32

W
(always 0000_0000h
reads 0)

41.3.2/781

F80F_F108

Port Clear Output Register (FGPIOE_PCOR)

32

W
(always 0000_0000h
reads 0)

41.3.3/781

F80F_F10C Port Toggle Output Register (FGPIOE_PTOR)

32

W
(always 0000_0000h
reads 0)

41.3.4/782

F80F_F110

Port Data Input Register (FGPIOE_PDIR)

32

R

0000_0000h

41.3.5/782

F80F_F114

Port Data Direction Register (FGPIOE_PDDR)

32

R/W

0000_0000h

41.3.6/783

41.3.1 Port Data Output Register (FGPIOx_PDOR)
This register configures the logic levels that are driven on each general-purpose output
pins.
Address: Base address + 0h offset
Bit
R
W

31

Reset

0

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

PDO
0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

FGPIOx_PDOR field descriptions
Field
31–0
PDO

Description
Port Data Output
Unimplemented pins for a particular device read as zero.
0
1

Logic level 0 is driven on pin, provided pin is configured for general-purpose output.
Logic level 1 is driven on pin, provided pin is configured for general-purpose output.

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Chapter 41 General-Purpose Input/Output (GPIO)

41.3.2 Port Set Output Register (FGPIOx_PSOR)
This register configures whether to set the fields of the PDOR.
Address: Base address + 4h offset
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

R

0

W

PTSO

Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

FGPIOx_PSOR field descriptions
Field

Description

31–0
PTSO

Port Set Output
Writing to this register will update the contents of the corresponding bit in the PDOR as follows:
0
1

Corresponding bit in PDORn does not change.
Corresponding bit in PDORn is set to logic 1.

41.3.3 Port Clear Output Register (FGPIOx_PCOR)
This register configures whether to clear the fields of PDOR.
Address: Base address + 8h offset
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

R

0

W

PTCO

Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

FGPIOx_PCOR field descriptions
Field
31–0
PTCO

Description
Port Clear Output
Writing to this register will update the contents of the corresponding bit in the Port Data Output Register
(PDOR) as follows:
0
1

Corresponding bit in PDORn does not change.
Corresponding bit in PDORn is cleared to logic 0.

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FGPIO memory map and register definition

41.3.4 Port Toggle Output Register (FGPIOx_PTOR)
Address: Base address + Ch offset
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

R

0

W

PTTO

Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

FGPIOx_PTOR field descriptions
Field

Description

31–0
PTTO

Port Toggle Output
Writing to this register will update the contents of the corresponding bit in the PDOR as follows:
0
1

Corresponding bit in PDORn does not change.
Corresponding bit in PDORn is set to the inverse of its existing logic state.

41.3.5 Port Data Input Register (FGPIOx_PDIR)
Address: Base address + 10h offset
Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

PDI

R
W
Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

FGPIOx_PDIR field descriptions
Field
31–0
PDI

Description
Port Data Input
Reads 0 at the unimplemented pins for a particular device. Pins that are not configured for a digital
function read 0. If the Port Control and Interrupt module is disabled, then the corresponding bit in PDIR
does not update.
0
1

Pin logic level is logic 0, or is not configured for use by digital function.
Pin logic level is logic 1.

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Chapter 41 General-Purpose Input/Output (GPIO)

41.3.6 Port Data Direction Register (FGPIOx_PDDR)
The PDDR configures the individual port pins for input or output.
Address: Base address + 14h offset
Bit
R
W

31

Reset

0

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

PDD
0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

FGPIOx_PDDR field descriptions
Field
31–0
PDD

Description
Port Data Direction
Configures individual port pins for input or output.
0
1

Pin is configured as general-purpose input, for the GPIO function.
Pin is configured as general-purpose output, for the GPIO function.

41.4 Functional description
41.4.1 General-purpose input
The logic state of each pin is available via the Port Data Input registers, provided the pin
is configured for a digital function and the corresponding Port Control and Interrupt
module is enabled.

41.4.2 General-purpose output
The logic state of each pin can be controlled via the port data output registers and port
data direction registers, provided the pin is configured for the GPIO function. The
following table depicts the conditions for a pin to be configured as input/output.
If

Then

A pin is configured for the GPIO function and the
corresponding port data direction register bit is clear.

The pin is configured as an input.

A pin is configured for the GPIO function and the
corresponding port data direction register bit is set.

The pin is configured as an output and and the logic state of
the pin is equal to the corresponding port data output register.

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Functional description

To facilitate efficient bit manipulation on the general-purpose outputs, pin data set, pin
data clear, and pin data toggle registers exist to allow one or more outputs within one port
to be set, cleared, or toggled from a single register write.
The corresponding Port Control and Interrupt module does not need to be enabled to
update the state of the port data direction registers and port data output registers including
the set/clear/toggle registers.

41.4.3 IOPORT
The GPIO registers are also aliased to the IOPORT interface on the Cortex-M0+ from
address $F800_0000. Accesses via the IOPORT interface occur in parallel with any
instruction fetches and will therefore complete in a single cycle. If the DMA attempts to
access the GPIO registers on the same cycle as an IOPORT access, then the DMA access
will stall until any IOPORT accesses have completed.
During Compute Operation, the GPIO registers remain accessible via the IOPORT
interface only. Since the clocks to the Port Control and Interrupt modules are disabled
during Compute Operation, the Pin Data Input Registers do not update with the current
state of the pins.

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Freescale Semiconductor, Inc.

Chapter 42
Touch Sensing Input (TSI)
42.1 Introduction
The touch sensing input (TSI) module provides capacitive touch sensing detection with
high sensitivity and enhanced robustness. Each TSI pin implements the capacitive
measurement by a current source scan, charging and discharging the electrode, once or
several times. A reference oscillator ticks the scan time and stores the result in a 16-bit
register when the scan completes. Meanwhile, an interrupt request is submitted to CPU
for post-processing if TSI interrupt is enabled and DMA function is not selected.The TSI
module can be periodically triggered to work in low power mode with ultra-low current
adder and wake CPU at the end of scan or the conversion result is out of the range
specified by TSI threshold. It provides a solid capacitive measurement module to the
implementation of touch keyboard, rotaries and sliders.

42.1.1 Features
TSI features includes:
• Support up to 16 external electrodes
• Automatic detection of electrode capacitance across all operational power modes
• Internal reference oscillator for high-accuracy measurement
• Configurable software or hardware scan trigger
• Fully support Freescale touch sensing software (TSS) library, see
www.freescale.com/touchsensing.
• Capability to wake MCU from low power modes
• Compensate for temperature and supply voltage variations
• High sensitivity change with 16-bit resolution register
• Configurable up to 4096 scan times.
• Support DMA data transfer

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Introduction

42.1.2 Modes of operation
This module supports the following operation modes.
Table 42-1. Operating modes
Mode

Description

Stop and low power stop

TSI module is fully functional in all of the stop modes as long
as TSI_GENCS[STPE] is set. The channel specified by
TSI_DATA[TSICH] will be scanned upon the trigger. After
scan finishes, either end-of-scan or out-of-range interrupt can
be selected to bring MCU out of low power modes.

Wait

TSI module is fully functional in this mode. When a scan
completes, TSI submits an interrupt request to CPU if the
interrupt is enabled.

Run

TSI module is fully functional in this mode. When a scan
completes, TSI submits an interrupt request to CPU if the
interrupt is enabled.

42.1.3 Block diagram
The following figure is a block diagram of the TSI module.
TSIEN

TSIIEN

STPE

Int. 1.8V

DVOLT

Voltage
Divider

TSI2
TSI3

ANALOG MUX

TSI0
TSI1

TSI_CNTH
+
–

TSI14

Write SWTS “1”

Electrode
Oscillator

16-bit Counter

TSI_CNTL

Reference Clock

Interrupt
TSICH
Control
Logic

MUX

Hardware Trigger

NSCN

Reference
Oscillator

TSI15
TSI_PENx

2

PS

STM

EXTCHRG

REFCHRG

CURSW

EOSF

SCNIP

TSIIEN

Figure 42-1. TSI module block diagram

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Freescale Semiconductor, Inc.

Chapter 42 Touch Sensing Input (TSI)

42.2 External signal description
The TSI module contains up to 16 external pins for touch sensing. The following table
describes each of the TSI external pins.
Table 42-2. TSI signal description
Name
TSI[15:0]

Port
TSI

Direction
I/O

Function

Reset state

TSI capacitive pins.
I/O
Switches driver that
connects directly to the
electrode pins TSI[15:0]
can operate as GPIO
pins.

42.2.1 TSI[15:0]
When TSI functionality is enabled , the TSI analog portion uses the corresponding
channel to connect external on-board touch capacitors. The PCB connection between the
pin and the touch pad must be kept as short as possible to reduce distribution capacity on
board.

42.3 Register definition
This section describes the memory map and control/status registers for the TSI module.
TSI memory map
Absolute
address
(hex)

Register name

Width
Access
(in bits)

Reset value

Section/
page

4004_5000

TSI General Control and Status Register (TSI0_GENCS)

32

R/W

0000_0000h

42.3.1/787

4004_5004

TSI DATA Register (TSI0_DATA)

32

R/W

0000_0000h

42.3.2/792

4004_5008

TSI Threshold Register (TSI0_TSHD)

32

R/W

0000_0000h

42.3.3/793

42.3.1 TSI General Control and Status Register (TSIx_GENCS)
This control register provides various control and configuration information for the TSI
module.

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Register definition

NOTE
When TSI is working, the configuration bits (GENCS[TSIEN],
GENCS[TSIIEN], and GENCS[STM]) must not be changed.
The EOSF flag is kept until the software acknowledge it.
Bit

31

R

OUTRGF

Address: 4004_5000h base + 0h offset = 4004_5000h
29

28

27

26

25

24

23

22

21

20

19

18

17

16

0
ESO
R

MODE

REFCHRG

DVOLT

EXTCHRG

Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Bit

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

EOSF

w1c

SCNIP

W

30

STPE STM

w1c

W

Reset

0
CURSW

NSCN

TSIIEN

PS

TSIEN

R

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

TSIx_GENCS field descriptions
Field

Description

31
OUTRGF

Out of Range Flag.

30–29
Reserved

This field is reserved.
This read-only field is reserved and always has the value 0.

28
ESOR

This flag is set if the result register of the enabled electrode is out of the range defined by the
TSI_THRESHOLD register. This flag is set only when TSI is configured in non-noise detection mode. It
can be read once the CPU wakes. Write "1" , when this flag is set, to clear it.

End-of-scan or Out-of-Range Interrupt Selection
This bit is used to select out-of-range or end-of-scan event to generate an interrupt.
0
1

Out-of-range interrupt is allowed.
End-of-scan interrupt is allowed.
Table continues on the next page...

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Chapter 42 Touch Sensing Input (TSI)

TSIx_GENCS field descriptions (continued)
Field
27–24
MODE

Description
TSI analog modes setup and status bits.
Set up TSI analog modes, especially, setting MODE[3:2] to not 2'b00 will configure TSI to noise detection
modes. MODE[1:0] take no effect on TSI operation mode and should always write to 2'b00 for setting up.
When reading this field will return the analog status. Refer to chapter "Noise detection mode" for details.
0000
0100

Set TSI in capacitive sensing(non-noise detection) mode.
Set TSI analog to work in single threshold noise detection mode and the frequency limitation circuit
is disabled.
Set TSI analog to work in single threshold noise detection mode and the frequency limitation circuit
is enabled to work in higher frequencies operations.
Set TSI analog to work in automatic noise detection mode.

1000
1100
23–21
REFCHRG

REFCHRG
These bits indicate the reference oscillator charge and discharge current value.
000
001
010
011
100
101
110
111

20–19
DVOLT

DVOLT
These bits indicate the oscillator's voltage rails as below.
00
01
10
11

18–16
EXTCHRG

DV = 1.03 V; VP = 1.33 V; Vm = 0.30 V.
DV = 0.73 V; VP = 1.18 V; Vm = 0.45 V.
DV = 0.43 V; VP = 1.03 V; Vm = 0.60 V.
DV = 0.29 V; VP = 0.95 V; Vm = 0.67 V.

EXTCHRG
These bits indicate the electrode oscillator charge and discharge current value.
000
001
010
011
100
101
110
111

15–13
PS

500 nA.
1 μA.
2 μA.
4 μA.
8 μA.
16 μA.
32 μA.
64 μA.

500 nA.
1 μA.
2 μA.
4 μA.
8 μA.
16 μA.
32 μA.
64 μA.

PS
These bits indicate the prescaler of the output of electrode oscillator.
000
001

Electrode Oscillator Frequency divided by 1
Electrode Oscillator Frequency divided by 2
Table continues on the next page...

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Register definition

TSIx_GENCS field descriptions (continued)
Field

Description
010
011
100
101
110
111

12–8
NSCN

NSCN
These bits indicate the scan number for each electrode. The scan number is equal to NSCN + 1, which
allows the scan time ranges from 1 to 32. By default, NSCN is configured as 0, which asserts the TSI
scans once on the selected eletrode channel.
00000
00001
00010
00011
00100
00101
00110
00111
01000
01001
01010
01011
01100
01101
01110
01111
10000
10001
10010
10011
10100
10101
10110
10111
11000
11001
11010
11011
11100
11101
11110
11111

7
TSIEN

Electrode Oscillator Frequency divided by 4
Electrode Oscillator Frequency divided by 8
Electrode Oscillator Frequency divided by 16
Electrode Oscillator Frequency divided by 32
Electrode Oscillator Frequency divided by 64
Electrode Oscillator Frequency divided by 128

Once per electrode
Twice per electrode
3 times per electrode
4 times per electrode
5 times per electrode
6 times per electrode
7 times per electrode
8 times per electrode
9 times per electrode
10 times per electrode
11 times per electrode
12 times per electrode
13 times per electrode
14 times per electrode
15 times per electrode
16 times per electrode
17 times per electrode
18 times per electrode
19 times per electrode
20 times per electrode
21 times per electrode
22 times per electrode
23 times per electrode
24 times per electrode
25 times per electrode
26 times per electrode
27 times per electrode
28 times per electrode
29 times per electrode
30 times per electrode
31 times per electrode
32 times per electrode

Touch Sensing Input Module Enable
This bit enables TSI module.
Table continues on the next page...

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Chapter 42 Touch Sensing Input (TSI)

TSIx_GENCS field descriptions (continued)
Field

Description
0
1

6
TSIIEN

Touch Sensing Input Interrupt Enable
This bit enables TSI module interrupt request to CPU when the scan completes. The interrupt will wake
MCU from low power mode if this interrupt is enabled.
0
1

5
STPE

This bit enables TSI module function in low power modes (stop, VLPS, LLS and VLLS{3,2,1}).

This bit specifies the trigger mode. User is allowed to change this bit when TSI is not working in progress.

This read-only bit indicates if scan is in progress. This bit will get asserted after the analog bias circuit is
stable after a trigger and it changes automatically by the TSI.

This flag is set when all active electrodes are finished scanning after a scan trigger. Write "1" , when this
flag is set, to clear it.
Scan not complete.
Scan complete.

CURSW
This bit specifies if the current sources of electrode oscillator and reference oscillator are swapped.
0
1

0
Reserved

No scan in progress.
Scan in progress.

End of Scan Flag

0
1
1
CURSW

Software trigger scan.
Hardware trigger scan.

Scan In Progress Status

0
1
2
EOSF

TSI is disabled when MCU goes into low power mode.
Allows TSI to continue running in all low power modes.

Scan Trigger Mode

0
1
3
SCNIP

TSI interrupt is disabled.
TSI interrupt is enabled.

TSI STOP Enable

0
1
4
STM

TSI module disabled.
TSI module enabled.

The current source pair are not swapped.
The current source pair are swapped.

This field is reserved.
This read-only field is reserved and always has the value 0.

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42.3.2 TSI DATA Register (TSIx_DATA )
Address: 4004_5000h base + 4h offset = 4004_5004h
31

30

29

28

27

26

25

24

23

0

21

20

19

0
DMAEN

R

22

TSICH
W

18

17

16

0

SWTS

Bit

Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Bit

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

0

0

0

0

0

0

TSICNT

R

W

Reset

0

0

0

0

0

0

0

0

0

TSIx_DATA field descriptions
Field
31–28
TSICH

Description
TSICH
These bits specify current channel to be measured. In hardware trigger mode (TSI_GENCS[STM] = 1), the
scan will not start until the hardware trigger occurs. In software trigger mode (TSI_GENCS[STM] = 0), the
scan starts immediately when TSI_DATA[SWTS] bit is written by 1.
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101

Channel 0.
Channel 1.
Channel 2.
Channel 3.
Channel 4.
Channel 5.
Channel 6.
Channel 7.
Channel 8.
Channel 9.
Channel 10.
Channel 11.
Channel 12.
Channel 13.
Table continues on the next page...

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Chapter 42 Touch Sensing Input (TSI)

TSIx_DATA field descriptions (continued)
Field

Description
1110
1111

27–24
Reserved

Channel 14.
Channel 15.

This field is reserved.
This read-only field is reserved and always has the value 0.

23
DMAEN

DMA Transfer Enabled
This bit is used together with the TSI interrupt enable bits(TSIIE, ESOR) to generate a DMA transfer
request instead of an interrupt.
0
1

22
SWTS

Interrupt is selected when the interrupt enable bit is set and the corresponding TSI events assert.
DMA transfer request is selected when the interrupt enable bit is set and the corresponding TSI
events assert.

Software Trigger Start
This write-only bit is a software start trigger. When STM bit is clear, write "1" to this bit will start a scan.
The electrode channel to be scanned is determinated by TSI_DATA[TSICH] bits.
0
1

21–16
Reserved

No effect.
Start a scan to determine which channel is specified by TSI_DATA[TSICH].

This field is reserved.
This read-only field is reserved and always has the value 0.

15–0
TSICNT

TSI Conversion Counter Value
These read-only bits record the accumulated scan counter value ticked by the reference oscillator.

42.3.3 TSI Threshold Register (TSIx_TSHD)
Address: 4004_5000h base + 8h offset = 4004_5008h
Bit
R
W

31

Reset

0

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

THRESH
0

0

0

0

0

0

0

0

8

7

6

5

4

3

2

1

0

0

0

0

0

0

0

0

THRESL
0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

TSIx_TSHD field descriptions
Field

Description

31–16
THRESH

TSI Wakeup Channel High-threshold

15–0
THRESL

TSI Wakeup Channel Low-threshold

This half-word specifies the high threshold of the wakeup channel.

This half-word specifies the low threshold of the wakeup channel.

42.4 Functional description
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Functional description

42.4.1 Capacitance measurement
The electrode pin capacitance measurement uses a dual oscillator approach. The
frequency of the TSI electrode oscillator depends on the external electrode capacitance
and the TSI module configuration. After going to a configurable prescaler, the TSI
electrode oscillator signal goes to the input of the module counter. The time for the
module counter to reach its module value is measured using the TSI reference oscillator.
The measured electrode capacitance is directly proportional to the time.

42.4.1.1 TSI electrode oscillator
The TSI electrode oscillator circuit is illustrated in the following figure. A configurable
constant current source is used to charge and discharge the external electrode
capacitance. A buffer hysteresis defines the oscillator delta voltage. The delta voltage
defines the margin of high and low voltage which are the reference input of the
comparator in different time.

Figure 42-8. TSI electrode oscillator circuit

The current source applied to the pad capacitance is controlled by the
SCANC[EXTCHRG]. The hysteresis delta voltage is defined in the module electrical
specifications present in the device Data Sheet. The figure below shows the voltage
amplitude waveform of the electrode capacitance charging and discharging with a
programmable current.

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Chapter 42 Touch Sensing Input (TSI)
Electrode Capacitor Charging and
Discharging with constant current

Electrode
Voltage

Hysteresis
Voltage Delta

Time

Figure 42-9. TSI electrode oscillator chart

The oscillator frequency is give by the following equation

Felec

I

2 * Celec * ΔV

Figure 42-10. Equation 1: TSI electrode oscillator frequency

Where:
I: constant current
Celec: electrode capacitance
ΔV: Hysteresis delta voltage
So by this equation, for example, an electrode with Celec= 20 pF, with a current source of
I = 16 µA and ΔV = 600 mV have the following oscillation frequency:

Felec

16 µA
2 * 20pF * 600mV

0.67MHz

Figure 42-11. Equation 2: TSI electrode oscillator frequency

The current source is used to accommodate the TSI electrode oscillator frequency with
different electrode capacitance sizes.

42.4.1.2 Electrode oscillator and counter module control
The TSI oscillator frequency signal goes through a prescaler defined by the GENCS[PS]
and then enters in a modulus counter. The bit field GENCS[NSCN] defines the maximum
count value of the modulus counter.

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Functional description

The pin capacitance sampling time is given by the time the module counter takes to go
from zero to its maximum value, defined by NSCN. The electrode sample time is
expressed by the following equation:
Tcap_samp

PS * NSCN
F elec

Using Equation 1.
Tcap_samp

2 * PS * NSCN * Celec * ΔV
I

Figure 42-12. Equation 3: Electrode sampling time

Where:
PS: prescaler value
NSCN: module counter maximum value
I: constant current
Celec: electrode capacitance
ΔV: Hysteresis delta voltage
By this equation we have that an electrode with C = 20 pF, with a current source of I = 16
µA and ΔV = 600 mV, PS = 2 and NSCN = 16 have the following sampling time:

Tcap_samp 2*2*16*20pF*600mV 48µs
16µA
42.4.1.3 TSI reference oscillator
The TSI reference oscillator has the same topology of the TSI electrode oscillator. The
TSI reference oscillator instead of using an external capacitor for the electrode oscillator
has an internal reference capacitor.
The TSI reference oscillator has an independent programmable current source controlled
by the SCANC[REFCHRG].
The reference oscillator frequency is given by the following equation:

Fref_osc

Iref
2 *Cref * ΔV

Figure 42-13. Equation 4: TSI reference oscillator frequency

Where:
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Chapter 42 Touch Sensing Input (TSI)

Cref: Internal reference capacitor
Iref: Reference oscillator current source
∆V : Hysteresis delta voltage
Considering Cref = 1.0 pF, Iref = 12 µA and ∆V = 600 mV, follows

Fref_osc

12µA
2 *1.0pF * 600mV

10.0MHz

42.4.2 TSI measurement result
The capacitance measurement result is defined by the number of TSI reference oscillator
periods during the sample time and is stored in the TSICHnCNT register.
TSICHnCNT = Tcap_samp * Fref_osc
Using Equation 2 and Equation 1 follows:
TSICHnCNT

Iref * PS *NSCN
* Celec
Cref * Ielec

Figure 42-14. Equation 5: Capacitance result value

In the example where Fref_osc = 10.0MHz and Tcap_samp = 48 µs, TSICHnCNT = 480

42.4.3 Enable TSI module
The TSI module can be fully functional in run, wait and low power modes. The
TSI_GENCS[TSIEN] bit must be set to enable the TSI module in run and wait mode.
When TSI_GENCS[STPE] bit is set, it allows the TSI module to work in low power
mode.

42.4.4 Software and hardware trigger
The TSI module allows a software or hardware trigger to start a scan. When a software
trigger is applied ( TSI_GENCS[STM] bit clear), the TSI_GENCS[SWTS] bit must be
written "1" to start the scan electrode channel that is identified by TSI_DATA[TSICH].
When a hardware trigger is applied ( TSI_GENCS[STM] bit set), the TSI will not start
scanning until the hardware trigger arrives. The hardware trigger is different depending
on the MCU configuration. Generally, it could be an event that RTC overflows. See chip
configuration section for details.
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Functional description

42.4.5 Scan times
The TSI provides multi-scan function. The number of scans is indicated by the
TSI_GENCS[NSCN] bits that allow the scan number from 1 to 32. When
TSI_GENCS[NSCN] is set to 0 (only once), the single scan is engaged. The 16-bit
counter accumulates all scan results until the NSCN time scan completes, and users can
read TSI_DATA[TSICNT] to get this accumulation. When DMA transfer is enabled, the
counter values can also be read out by DMA engine.

42.4.6 Clock setting
TSI is built with dual oscillator architecture. In normal sensing application, the reference
oscillator clock is the only clock source for operations. The reference clock is used to
measure the electrode oscillator by ticking a 16-bit counter. The reference oscillator
frequency depends on the current source setting. Please refer to the Current source for
more details.
The output of electrode oscillator has several prescalers up to 128 indicated by
TSI_GENCS[PS]bits. This allows a flexible counter configuration for different electrode
oscillator frequency.

42.4.7 Reference voltage
The TSI module offers a internal reference voltage for both electrode oscillator and
reference oscillator. The internal reference voltage can work in low power modes even
when the MCU regulator is partially powered down, which is ideally for low-power touch
detection.
The charge and discharge difference voltage is configurable upon the setting of
TSI_GENCS[DVOLT] bits. The following table shows the all the delta voltage
configurations.Note this table doesn't apply to noise mode, where the details should be
consult form noise modes chapters.
Table 42-11. Delta voltage configuration
DVOLT

Vp (V)

Vm (V)

ΔV (V)

00

1.328

0.302

1.026

01

1.111

0.519

0.592

10

0.986

0.644

0.342

11

0.914

0.716

0.198

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Chapter 42 Touch Sensing Input (TSI)

42.4.8 Current source
The TSI module supports eight different current source power to increment from 500 nA
to 64uA. The TSI_GENCS[EXTCHRG] bits determine the current of electrode oscillator
that charges and discharges external electrodes. The TSI_GENCS[REFCHRG] bits
determine the current of reference oscillator on which the internal reference clock
depends. The lower current source takes more time for charge and discharge, which is
useful to detect high-accuracy change. The higher current source takes less time, which
can be used to charge a big electrode by less power consumption.
The TSI_GENCS[CURSW] bit allows the current source to swap, so that the reference
oscillator and electrode oscillator use the opposite current sources. When
TSI_GENCS[CURSW] is set and the current sources are swapped, the
TSI_GENCS[EXTCHRG] bits and TSI_GENCS[REFCHRG] bits still control the
corresponding current sources, that is, TSI_GENCS[EXTCHRG] controls the reference
oscillator current and TSI_GENCS[REFCHRG] controls the electrode oscillator current.

42.4.9 End of scan
As a scan starts, [SCNIP] bit is set to indicate scan is in progress. When the scan
completes, the [EOSF] bit is set. Before clearing the [EOSF] bit, the value in
TSI_DATA[TSICNT] must be read. If the TSI_GENCS[TSIIEN] bit is set
andTSI_GENCS[DMAEN]is not set, an interrupt is submitted to CPU for postprocessing immediately. The interrupt is also optional to wake MCU to execute ISR if it
is in low power mode. When DMA function is enabled by setting TSI_GENCS[TSIIEN]
and TSI_GENCS[ESOR], as soon as scan completes, a DMA transfer request is asserted
to DMA controller for data movement, generally, DMA engine will fetch TSI conversion
result from TSI_DATA register,store it to other memory space and then refresh the TSI
scan channel index(TSI_DATA[TSICH]) for next loop. When DMA transfer is done,
TSI_GENCS[EOSF] is cleared automatically.

42.4.10 Out-of-range interrupt
If enabled, TSI will scan the electrode specified by TSI_DATA[TSICH] as soon as the
trigger arrives. The TSI_GENCS[OUTRGF] flag generates a TSI interrupt request if the
TSI_GENCS[TSIIE] bit is set and GENCS[ESOR] bit is cleared. With this configuration,
after the end-of-electrode scan, the electrode capacitance will be converted and stored to
the result register TSI_DATA[TSICNT], the out-of-range interrupt is only requested if
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Functional description

there is a considerable capacitance change defined by the TSI_TSHD. For instance, if in
low power mode the electrode capacitance does not vary, the out-of-range interrupt does
not interrupt the CPU. This interrupt will not happen in noise detection mode. It is worthy
to note that when the counter value reaches 0xFFFF is treated as an extreme case the outof-range will not happen. Also in noise detection mode, the out-of-range will not assert
either.

42.4.11 Wake up MCU from low power modes
In low power modes, once enabled by TSI_GENCS[STPE] and TSI_GENCS[TSIIE],
TSI can bring MCU out of its low power modes(STOP, VLPS, VLLS,etc) by either end
of scan or out of range interrupt, that is, if TSI_GENCS[ESOR] is set, end of scan
interrupt is selected and otherwise, out of range is selected.

42.4.12 DMA function support
Transmit by DMA is supported only when TSI_DATA[DMAEN] is set. A DMA transfer
request is asserted when all of TSI_GENCS[EOSF], TSI_GENCS[ESOR] and
TSI_GENCS[TSIIE] are set. Then the on-chip DMA controller detects this request and
transfers data between memory space and TSI register space. After the data tranfer, DMA
DONE is asserted to clear TSI_GENCS[EOSF] automatically. This function is normally
used by DMA controller to get the conversion result from TSI_DATA[TSICNT] upon a
end-of-scan event and then refresh the channel index(TSI_DATA[TSICH]) for next
trigger. DMA function is not available when MCU is in stop modes.

42.4.13 Noise detection mode
The noise detection mode change the circuit configuration as shown in the following
figure. With this configuration, it is possible to detect touch with high levels of EMC
noise present. To enter the test mode, see TSIx_GENCS[MODE] register field.
In noise detection mode the reference oscillator has the same configuration except the
output goes to Counter2 and this counter will have the it's maximum count set by NSCN.
2^(PS). This means this oscillator will setup the noise detection mode sense duration.
The blocks of external oscillator is changed and instead of an oscillator the circuit
implements an RF amplitude detection. The thrshold for this amplitude detection is set by
DVOLT register bits.
Also the external voltage is biased by vmid voltage with a Rs series resistance.
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Chapter 42 Touch Sensing Input (TSI)

The vmid voltage is defined as V(vmid) = (V(vp) + V(vm))/2.
The Rs value is defined by i_ext_3v<2:0> register bits.

Figure 42-15. TSI circuit in noise detection mode

To determine the noise level the below algorithm can be used:
1. Initialize Rs = maxrs; Dvolt = minDv (set other configurations also)
2. Perform a noise cycle.
3. If TSIcounter < 3, go to step 8
4. If Rs = minrs, go to step 6.
5. Reduce value of Rs. go to step 2
6. If Dvolt = maxDv, go to END
7. Increase value of Dvolt. Set Rs = maxrs. go to step 2
8. If Rs > minrs, (Reduce value of Rs, go to END)
9. Rs = maxrs, reduce value of Dvolt.
10. END Get value of Rs and Dvolt.

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Functional description

One example of noise detection mode is shown in the following figure. in this figure the
TSI is working in capacitive mode until 30uS when it is changed to noise detection mode.
In noise detection mode the selected pad is biased with 0.815V and all AC waveform in
this pad is caused by a noise source external to IC.
It is possible to observe in the following figure that, in noise detection mode, the clkref
output has the peak detection and the number of detected peaks can be counted or used by
digital block. The clkext output has the internal oscillator output and can be used to set
the maximum noise detection time window.
The waveform of the following figure shows two operations during noise detection mode:
• The V(vp) and V(vm) thresholds are changed in 34.4 µs.
• The Rs series resistance value is changed between 184 kΩ (iext<2:0>=011) and 32
kΩ (iext<2:0>=101). Because of this Rs change the amplitude of noise waveform
change also.

Figure 42-16. TSI noise detection mode waveform

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Chapter 42 Touch Sensing Input (TSI)

42.4.13.1 Automatic noise mode
This mode is set by MODE[3:2] = 11 (noise mode 3). In this mode, the thresholds are
incremented internally by the module until the point that there is no noise voltage
trepassing the threshold.
The following diagram shows how it is done. The threshold comparator output goes to a
counter and as the DVOLT control bits are increased the DVOLT thresholds are
increased as well. The four bits are counted until 1111 (=15) and the counter is stop with
this maximum value.

Figure 42-17. Block diagram automatic noise threshold operation

The signals that have different behavior in this noise mode (wrt capacitive mode) are
shown in the following table.
Table 42-12. Signal properties in automatic noise operation mode
Name

Function

MODE[3:2]

11 - Noise mode operation
with frequency limitation and
automatic threshold counter.

I/O type
I

Power Up/Reset state
00

Table continues on the next page...

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Functional description

Table 42-12. Signal properties in automatic noise operation mode (continued)
Name
EXTCHRG[2:1]

Function

I/O type

In this operation mode these I
bits select the number of filter
bits.

Power Up/Reset state
00

00 - 3 filter bits
01 - 2 filter bits
10 - 1 filter bit
11 - no filter bit
EXTCHRG[0]

In this operation mode this
bits selects the series
resistance.

I

0

0 - uses Rs=32 kΩ
0 - uses Rs=187 kΩ
Independent of this bit
selection the threshold 15 is
done with Rs = 5.5 kΩ
DVOLT[1:0]

Select voltage rails of the
internal oscillator

I

00

MODE[3:0]

DVOLT counter bits output.

O

0000

This register content is reset
always the MODE[3:2] is not
11, and after beginning of
automatic noise mode
operation.

42.4.13.2 Single threshold noise modes
These modes reset by MODE[3:2]=01 and 10. The difference between these two modes
is that in mode 2 (MODE[3:2]=10) there is a frequency limitation circuit that enables the
circuit to operate in higher frequencies. In mode 1 (MODE[3:2]=01) this frequency
limitation circuit is not enabled.
In this mode the thresholds are set by user via register bits as described in the following
table.
During these modes the internal oscillator rails are set to the maximum (equivalent to
DVOLT[1:0]=00).
Table 42-13. Signal properties in single noise modes (1,2)
Name
MODE[3:2]

Function
01 or 10- Single thrshold noise mode operation.

I/O type

Power up /
reset

I

00

Table continues on the next page...

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Chapter 42 Touch Sensing Input (TSI)

Table 42-13. Signal properties in single noise modes (1,2) (continued)
Name
DVOLT[1:0],
EXTCHRG[2:1]

Function
In this operation mode these 4 bits are used select the noise
threshold.

I/O type

Power up /
reset

I

XXXX

I

XX

0000 - DVpm = 0.038 V, Vp = 0.834 V, Vm = 0.796 V
0001 - DVpm = 0.050 V, Vp = 0.830 V, Vm = 0.790 V
0010 - DVpm = 0.066 V, Vp = 0.848 V, Vm = 0.782 V
0011 - DVpm = 0.087 V, Vp = 0.858 V, Vm = 0.772 V
0100 - DVpm = 0.114 V, Vp = 0.872 V, Vm = 0.758 V
0101 - DVpm = 0.150 V, Vp = 0.890 V, Vm = 0.740 V
0110 - DVpm = 0.197 V, Vp = 0.914 V, Vm = 0.716 V
0111 - DVpm = 0.260 V, Vp = 0.945 V, Vm = 0.685 V
1000 - DVpm = 0.342 V, Vp = 0.986 V, Vm = 0.644 V
1001 - DVpm = 0.450 V, Vp = 1.040 V, Vm = 0.590 V
1010 - DVpm = 0.592 V, Vp = 1.111 V, Vm = 0.519 V
1011 - DVpm = 0.780 V, Vp = 1.205 V, Vm = 0.425 V
1100 - DVpm = 1.026 V, Vp = 1.328 V, Vm = 0.302 V
1101 - DVpm = 1.350 V, Vp = 1.490 V, Vm = 0.140 V
1110 - DVpm = 1.630 V, Vp = 1.630 V, Vm = 0 V
1111 - DVpm = 1.630 V, Vp = 1.630 V, Vm = 0 V
EXTCHRG[0]

In this operation mode this bits selects the series resistance.
0 - uses Rs = 32 kΩ.
1- uses Rs = 187 kΩ.
Independent of this bit selection the threshold 15 is done with Rs =
5.5 kΩ.

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Appendix A
Revision History of this Document
This appendix describes corrections to the this reference manual for convenience. Grammatical and
formatting changes are not listed here unless the meaning of something changed.

A.1

Changes between revisions 3 and 2
Table A-1. Changes between revisions 3 and 2
Chapter

Description

Flash Memory Module
(FTFA)

• Updated register absolute address.

12-bit Digital-to-Analog
Converter (DAC)

• Updated register absolute address.

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A-1

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Document Number: KL25P80M48SF0RM
Rev. 3, September 2012

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PDF Version                     : 1.6
Linearized                      : No
Keywords                        : KL25P80M48SF0RM, MKL25Z128VLK4, MKL25Z32VFM4, MKL25Z32VLK4, MKL25Z64VFM4, MKL25Z128VLH4, MKL25Z64VFT4, MKL25Z128VFT4, MKL25Z32VLH4, MKL25Z64VLK4, MKL25Z128VFM4, MKL25Z32VFT4, MKL25Z64VLH4, reference manual, Kinetis, microcontroller, MCU, Cortex-M, ARM, specification, architecture, features, registers, Cortex-M0+, Kinetis L, L-series, KL2x, KL25, USB
Modify Date                     : 2015:02:18 18:27:15-06:00
Trapped                         : False
Create Date                     : 2012:09:26 04:06:19-06:00
Author                          : Freescale Semiconductor Inc.
Page Mode                       : UseOutlines
XMP Toolkit                     : Adobe XMP Core 5.1.0-jc003
Format                          : application/pdf
Producer                        : Antenna House PDF Output Library 2.6.0 (Linux64); modified using iText® 5.5.4 ©2000-2014 iText Group NV (AGPL-version)
Creator Tool                    : AH Formatter V5.2 MR1 (5,2,2010,1221) for Linux64
Subject                         : KL25P80M48SF0RM, MKL25Z128VLK4, MKL25Z32VFM4, MKL25Z32VLK4, MKL25Z64VFM4, MKL25Z128VLH4, MKL25Z64VFT4, MKL25Z128VFT4, MKL25Z32VLH4, MKL25Z64VLK4, MKL25Z128VFM4, MKL25Z32VFT4, MKL25Z64VLH4, reference manual, Kinetis, microcontroller, MCU, Cortex-M, ARM, specification, architecture, features, registers, Cortex-M0+, Kinetis L, L-series, KL2x, KL25, USB
Description                     : Kinetis KL25 Reference Manual: 48MHz ultra low power ARM Cortex-M0+ microcontroller (MCU) with USB, up to 128KB Flash / 16KB SRAM (32-80 pin)
Creator                         : Freescale Semiconductor Inc.
Title                           : Kinetis KL25: 48MHz Cortex-M0+ 32-128KB Flash 32-80 pin
Has XFA                         : No
Page Count                      : 807

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