GD32F1x0 User Manual

User Manual:

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GigaDevice Semiconductor Inc.
GD32F1x0
ARM® Cortex™-M3 32-bit MCU
User Manual
Revision 3.0
( Jun. 2016 )
GD32F1x0 User Manual
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Table of Contents
Table of Contents ........................................................................................................... 1
List of Figures .............................................................................................................. 15
List of Tables ................................................................................................................ 23
1. System and memory architecture .......................................................................... 1
1.1. ARM Cortex-M3 processor ...................................................................................................... 1
1.2. System architecture ................................................................................................................ 2
1.3. Memory map .......................................................................................................................... 5
1.3.1. Bit-banding ............................................................................................................................................ 8
1.3.2. On-chip SRAM memory ......................................................................................................................... 8
1.3.3. On-chip Flash memory .......................................................................................................................... 9
1.4. Boot configuration ................................................................................................................ 10
1.5. System configuration registers (SYSCFG) ............................................................................... 11
1.5.1. System configuration register 0 (SYSCFG_CFG0) ................................................................................. 11
1.5.2. System configuration register 1 (SYSCFG_CFG1) ................................................................................. 12
1.5.3. EXTI sources selection register 0 (SYSCFG_EXTISS0) ........................................................................... 12
1.5.4. EXTI sources selection register 1 (SYSCFG_EXTISS1) ........................................................................... 14
1.5.5. EXTI sources selection register 2 (SYSCFG_EXTISS2) ........................................................................... 15
1.5.6. EXTI sources selection register 3 (SYSCFG_EXTISS3) ........................................................................... 16
1.5.7. System configuration register 2 (SYSCFG_CFG2) ................................................................................. 17
1.6. Device electronic signature ................................................................................................... 18
1.6.1. Memory density information .............................................................................................................. 19
1.6.2. Unique device ID (96 bits) ................................................................................................................... 19
2. Power management unit (PMU) ............................................................................ 21
2.1. Introduction .......................................................................................................................... 21
2.2. Main features ....................................................................................................................... 21
2.3. Function description ............................................................................................................. 21
2.3.1. Battery backup domain ....................................................................................................................... 23
2.3.2. VDD/VDDA power domain ....................................................................................................................... 24
2.3.3. 1.2V power domain for GD32F130xx and GD32F150xx devices.......................................................... 26
2.3.4. 1.8V power domain for GD32F170xx and GD32F190xx devices.......................................................... 26
2.3.5. Power saving modes ............................................................................................................................ 26
2.4. PMU registers ....................................................................................................................... 28
2.4.1. Control register (PMU_CTL) ................................................................................................................. 28
2.4.2. Power control/status register (PMU_CS) ............................................................................................. 31
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3. Flash memory controller (FMC) ............................................................................ 33
3.1. Introduction .......................................................................................................................... 33
3.2. Main features ....................................................................................................................... 33
3.3. Function description ............................................................................................................. 33
3.3.1. Flash memory architecture .................................................................................................................. 33
3.3.2. Read operations ................................................................................................................................... 34
3.3.3. Unlock the FMC_CTL register .............................................................................................................. 35
3.3.4. Page erase ........................................................................................................................................... 35
3.3.5. Mass erase ........................................................................................................................................... 36
3.3.6. Main flash programming ..................................................................................................................... 37
3.3.7. Option byte erase ................................................................................................................................ 38
3.3.8. Option byte programming ................................................................................................................... 39
3.3.9. Option byte description ....................................................................................................................... 39
3.3.10. Page erase/Program protection........................................................................................................... 40
3.3.11. Security protection .............................................................................................................................. 41
3.4. FMC registers ........................................................................................................................ 42
3.4.1. Wait state register (FMC_WS) ............................................................................................................. 42
3.4.2. Unlock key register (FMC_KEY) ............................................................................................................ 42
3.4.3. Option byte unlock key register (FMC_OBKEY) ................................................................................... 43
3.4.4. Status register (FMC_STAT) .................................................................................................................. 43
3.4.5. Control register (FMC_CTL) ................................................................................................................. 44
3.4.6. Address register (FMC_ADDR) ............................................................................................................. 46
3.4.7. Option byte status register (FMC_OBSTAT) ......................................................................................... 46
3.4.8. Write protection register (FMC_WP) ................................................................................................... 47
3.4.9. Wait state enable register (FMC_WSEN) ............................................................................................. 47
3.4.10. Product ID register (FMC_PID) ............................................................................................................. 48
4. Reset and clock unit (RCU) ................................................................................... 50
4.1. Reset control unit (RCTL) ....................................................................................................... 50
4.1.1. Introduction ......................................................................................................................................... 50
4.1.2. Function description ............................................................................................................................ 50
4.2. Clock control unit (CCTL) ....................................................................................................... 51
4.2.1. Introduction ......................................................................................................................................... 51
4.2.2. Main features ...................................................................................................................................... 54
4.2.3. Function description ............................................................................................................................ 54
4.3. RCU registers ........................................................................................................................ 59
4.3.1. Control register 0 (RCU_CTL0) ............................................................................................................. 59
4.3.2. Configuration register 0 (RCU_CFG0) .................................................................................................. 60
4.3.3. Interrupt register (RCU_INT) ................................................................................................................ 67
4.3.4. APB2 reset register (RCU_APB2RST) .................................................................................................... 73
4.3.5. APB1 reset register (RCU_APB1RST) .................................................................................................... 74
4.3.6. AHB enable register (RCU_AHBEN) ..................................................................................................... 79
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4.3.7. APB2 enable register (RCU_APB2EN) .................................................................................................. 81
4.3.8. APB1 enable register (RCU_APB1EN) .................................................................................................. 82
4.3.9. Backup domain control register (RCU_BDCTL) .................................................................................... 87
4.3.10. Reset source /clock register (RCU_RSTSCK) ......................................................................................... 89
4.3.11. AHB reset register (RCU_AHBRST) ....................................................................................................... 91
4.3.12. Configuration register 1 (RCU_CFG1) .................................................................................................. 92
4.3.13. Configuration register 2 (RCU_CFG2) .................................................................................................. 93
4.3.14. Control register 1 (RCU_CTL1) ............................................................................................................. 95
4.3.15. Configuration register 3 (RCU_CFG3) of GD32F170xx and GD32F190xx devices ................................ 97
4.3.16. Additional enable register (RCU_ADDEN) ........................................................................................... 97
4.3.17. Additional reset register (RCU_ADDRST) ............................................................................................. 98
4.3.18. Voltage key register (RCU_VKEY) ......................................................................................................... 98
4.3.19. Deep-sleep mode voltage register (RCU_DSV) .................................................................................... 99
4.3.20. Power down voltage select register (RCU_PDVSEL) of GD32F130xx and GD32F150xx devices ........ 100
5. General-purpose and alternate-function I/Os (GPIO and AFIOs) ..................... 101
5.1. Introduction ........................................................................................................................ 101
5.2. Main features ..................................................................................................................... 101
5.3. Function description ........................................................................................................... 101
5.3.1. GPIO pin configuration ...................................................................................................................... 103
5.3.2. Alternate functions (AF) .................................................................................................................... 103
5.3.3. Additional functions .......................................................................................................................... 103
5.3.4. Input configuration ............................................................................................................................ 103
5.3.5. Output configuration ......................................................................................................................... 104
5.3.6. Analog configuration ......................................................................................................................... 105
5.3.7. Alternate function (AF) configuration ................................................................................................ 105
5.3.8. GPIO locking function ........................................................................................................................ 106
5.4. GPIO registers ..................................................................................................................... 106
5.4.1. Port control register (GPIOx_CTL) (x=A..D,F) ..................................................................................... 106
5.4.2. Port output mode register (GPIOx_OMODE) (x=A..D,F) .................................................................... 108
5.4.3. Port output speed register (GPIOx_OSPD) (x=A..D,F) ........................................................................ 110
5.4.4. Port pull-up/down register (GPIOx_PUD) (x=A..D,F) ......................................................................... 111
5.4.5. Port input status register (GPIOx_ISTAT) (x=A..D,F) ........................................................................... 113
5.4.6. Port output control register (GPIOx_OCTL) (x=A..D,F) ....................................................................... 113
5.4.7. Port bit operate register (GPIOx_BOP) (x=A..D,F) .............................................................................. 114
5.4.8. Port configuration lock register (GPIOx_LOCK) (x=A, B) .................................................................... 114
5.4.9. Alternate function selected register0 (GPIOx_AFSEL0) (x=A, B, C) .................................................... 115
5.4.10. Alternate function selected register1 (GPIOx_AFSEL1) (x=A,B,C) ...................................................... 116
5.4.11. Bit clear register (GPIOx_BC) (x=A..D,F) ............................................................................................. 118
5.4.12. Port bit toggle register (GPIOx_TGx) (x=A..D,F) of GD32F170xx and GD32F190xx devices ............... 118
6. CRC calculation unit ............................................................................................ 119
6.1. Introduction ........................................................................................................................ 119
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6.2. Main features ..................................................................................................................... 119
6.3. Function description ........................................................................................................... 120
6.4. CRC Registers ...................................................................................................................... 121
6.4.1. Data Register (CRC_DATA) ................................................................................................................. 121
6.4.2. Free Data Register (CRC_FDATA) ........................................................................................................ 121
6.4.3. Control Register (CRC_CTL) ................................................................................................................ 122
6.4.4. Initialization Data Register (CRC_IDATA) ............................................................................................ 123
7. Interrupts and events .......................................................................................... 124
7.1. Introduction ........................................................................................................................ 124
7.2. Main features ..................................................................................................................... 124
7.3. Function description ........................................................................................................... 124
7.3.1. NVIC and exception/interrupt processing ......................................................................................... 124
7.3.2. External Interrupt and Event (EXTI) ................................................................................................... 128
7.4. Interrupts and EXTI registers ............................................................................................... 131
7.4.1. Interrupt Enable register (EXTI_INTEN) ............................................................................................. 131
7.4.2. Event enable register (EXTI_EVEN) .................................................................................................... 132
7.4.3. Rising edge trigger enable register (EXTI_RTEN) ............................................................................... 132
7.4.4. Falling edge trigger enable register (EXTI_FTEN) ............................................................................... 133
7.4.5. Software interrupt event register (EXTI_SWIEV) ............................................................................... 134
7.4.6. Pending register (EXTI_PD) ................................................................................................................ 135
8. Direct memory access controller (DMA) ............................................................ 136
8.1. Introduction ........................................................................................................................ 136
8.2. Main features ..................................................................................................................... 136
8.3. Function description ........................................................................................................... 136
8.3.1. DMA transfers .................................................................................................................................... 136
8.3.2. Arbitration among channels .............................................................................................................. 137
8.3.3. Next address generation algorithm ................................................................................................... 138
8.3.4. Circulation mode ............................................................................................................................... 138
8.3.5. Memory to memory mode ................................................................................................................ 138
8.3.6. Interrupt requests ............................................................................................................................. 138
8.3.7. DMA channel configuration procedure ............................................................................................. 139
8.3.8. DMA request mapping ...................................................................................................................... 139
8.4. DMA registers ..................................................................................................................... 141
8.4.1. Interrupt flag register (DMA_INTF) .................................................................................................... 141
8.4.2. Interrupt flag clear register (DMA_INTC) ........................................................................................... 142
8.4.3. Channel x control registers (DMA_CHxCTL0) ..................................................................................... 143
8.4.4. Channel x counter registers (DMA_CHxCNT) ..................................................................................... 144
8.4.5. Channel x peripheral base address registers (DMA_CHxPADDR) ...................................................... 145
8.4.6. Channel x memory base address registers (DMA_CHxMADDR) ........................................................ 145
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9. Timer (TIMERx) ..................................................................................................... 147
9.1. Advanced timer (TIMER0) ................................................................................................... 148
9.1.1. Introduction ....................................................................................................................................... 148
9.1.2. Main features .................................................................................................................................... 148
9.1.3. Function description .......................................................................................................................... 148
9.1.4. TIMER0 registers ................................................................................................................................ 180
9.2. General timers (TIMER1/TIMER2) ....................................................................................... 204
9.2.1. Introduction ....................................................................................................................................... 204
9.2.2. Main features .................................................................................................................................... 204
9.2.3. Function description .......................................................................................................................... 204
9.2.4. TIMER1/TIMER2 registers .................................................................................................................. 228
9.3. Basic timer (TIMER5) ........................................................................................................... 250
9.3.1. Introduction ....................................................................................................................................... 250
9.3.2. Main features .................................................................................................................................... 250
9.3.3. Function description .......................................................................................................................... 250
9.3.4. TIMER5 registers ................................................................................................................................ 253
9.4. General timer (TIMER13) .................................................................................................... 258
9.4.1. Introduction ....................................................................................................................................... 258
9.4.2. Main features .................................................................................................................................... 258
9.4.3. Function description .......................................................................................................................... 258
9.4.4. TIMER13 registers .............................................................................................................................. 270
9.5. General timer (TIMER14) .................................................................................................... 279
9.5.1. Introduction ....................................................................................................................................... 279
9.5.2. Main features .................................................................................................................................... 279
9.5.3. Function description .......................................................................................................................... 279
9.5.4. TIMER14 registers .............................................................................................................................. 302
9.6. General timer (TIMER15/TIMER16) ..................................................................................... 321
9.6.1. Introduction ....................................................................................................................................... 321
9.6.2. Main features .................................................................................................................................... 321
9.6.3. Function description .......................................................................................................................... 321
9.6.4. TIMER15/TIMER16 registers .............................................................................................................. 337
10. Infrared ray port (IFRR) .................................................................................... 352
10.1. Introduction .................................................................................................................... 352
10.2. Main features .................................................................................................................. 352
10.3. Function description ........................................................................................................ 352
11. Watchdog timer (WDGT) .................................................................................. 354
11.1. Free watchdog timer (FWDGT) ........................................................................................ 354
11.1.1. Introduction ....................................................................................................................................... 354
11.1.2. Main features .................................................................................................................................... 354
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11.1.3. Function description .......................................................................................................................... 354
11.1.4. FWDGT registers ................................................................................................................................ 356
11.2. Window watchdog timer (WWDGT) ................................................................................ 360
11.2.1. Introduction ....................................................................................................................................... 360
11.2.2. Main features .................................................................................................................................... 360
11.2.3. Function description .......................................................................................................................... 360
11.2.4. WWDGT registers .............................................................................................................................. 362
12. Analog to digital converter (ADC) ................................................................... 364
12.1. Introduction .................................................................................................................... 364
12.2. Main features .................................................................................................................. 364
12.3. Function description ........................................................................................................ 366
12.3.1. Calibration (ADC_CLB) ....................................................................................................................... 368
12.3.2. Dual clock domain architecture ......................................................................................................... 368
12.3.3. Regular and inserted channel groups ................................................................................................ 368
12.3.4. Conversion modes ............................................................................................................................. 369
12.3.5. Analog watchdog ............................................................................................................................... 372
12.3.6. Inserted channel management .......................................................................................................... 372
12.3.7. Data alignment .................................................................................................................................. 373
12.3.8. Programmable sample time .............................................................................................................. 373
12.3.9. External trigger .................................................................................................................................. 373
12.3.10. DMA request ................................................................................................................................. 374
12.3.11. Temperature sensor and internal reference voltage VREF .............................................................. 374
12.3.12. Battery voltage monitoring ........................................................................................................... 375
12.3.13. ADC interrupts ............................................................................................................................... 375
12.3.14. Programmable resolution (RES) - fast conversion mode for GD32F170xx and GD32F190xx devices
375
12.3.15. Oversampling for GD32F170xx and GD32F190xx devices ............................................................. 376
12.4. ADC registers ................................................................................................................... 379
12.4.1. Status register (ADC_STAT) ................................................................................................................ 379
12.4.2. Control register 0 (ADC_CTL0) ........................................................................................................... 380
12.4.3. Control register 1 (ADC_CTL1) ........................................................................................................... 383
12.4.4. Sampling time register 0 (ADC_SAMPT0) .......................................................................................... 385
12.4.5. Sampling time register 1 (ADC_SAMPT1) .......................................................................................... 386
12.4.6. Inserted channel data offset registers (ADC_IOFFx) (x=0..3) ............................................................. 387
12.4.7. Watchdog high threshold register (ADC_WDHT) ............................................................................... 387
12.4.8. Watchdog low threshold register (ADC_WLT) ................................................................................... 388
12.4.9. Regular sequence register 0 (ADC_RSQ0) ......................................................................................... 388
12.4.10. Regular sequence register 1 (ADC_RSQ1) ..................................................................................... 389
12.4.11. Regular sequence register 2 (ADC_RSQ2) ..................................................................................... 389
12.4.12. Inserted sequence register (ADC_ISQ) .......................................................................................... 389
12.4.13. Inserted data registers (ADC_IDATAx) (x= 0..3) .............................................................................. 390
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12.4.14. Regular data register (ADC_RDATA) ............................................................................................... 391
12.4.15. Oversampling control register (ADC_OVSAMPCTL) of GD32F170xx and GD32F190xx devices .... 391
13. Digital-to-analog converter (DAC) ................................................................... 393
13.1. DAC Introduction ............................................................................................................. 393
13.2. DAC Main features .......................................................................................................... 393
13.3. DAC Function description ................................................................................................ 394
13.3.1. DAC enable ........................................................................................................................................ 394
13.3.2. DAC output buffer enable .................................................................................................................. 394
13.3.3. DAC data format ................................................................................................................................ 395
13.3.4. DAC conversion .................................................................................................................................. 395
13.3.5. DAC output voltage ........................................................................................................................... 396
13.3.6. DMA request ..................................................................................................................................... 396
13.3.7. DAC trigger ........................................................................................................................................ 396
13.3.8. DAC concurrent conversion for GD32F170xx and GD32F190xx devices............................................ 397
13.4. DAC registers ................................................................................................................... 398
13.4.1. Control register (DAC_CTL) ................................................................................................................ 398
13.4.2. Software trigger register (DAC_SWT) ................................................................................................ 401
13.4.3. DAC0 12-bit right-aligned data holding register (DAC0_R12DH) ....................................................... 402
13.4.4. DAC0 12-bit left-aligned data holding register (DAC0_L12DH) .......................................................... 403
13.4.5. DAC0 8-bit right-aligned data holding register (DAC0_R8DH) ........................................................... 403
13.4.6. DAC1 12-bit right-aligned data holding register (DAC1_R12DH) of GD32F170xx and GD32F190xx
devices 404
13.4.7. DAC1 12-bit left-aligned data holding register (DAC1_L12DH) of GD32F170xx and GD32F190xx
devices 404
13.4.8. DAC1 8-bit right-aligned data holding register (DAC1_R8DH) of GD32F170xx and GD32F190xx
devices 405
13.4.9. DAC concurrent mode 12-bit right-aligned data holding register (DACC_R12DH) of GD32F170xx and
GD32F190xx devices .......................................................................................................................................... 405
13.4.10. DAC concurrent mode 12-bit left-aligned data holding register (DACC_L12DH) of GD32F170xx and
GD32F190xx devices .......................................................................................................................................... 406
13.4.11. DAC concurrent mode 8-bit right-aligned data holding register (DACC_R8DH) of GD32F170xx and
GD32F190xx devices .......................................................................................................................................... 406
13.4.12. DAC0 data output register (DAC0_DO) .......................................................................................... 407
13.4.13. DAC1 data output register (DAC1_DO) of GD32F170xx and GD32F190xx devices ....................... 407
13.4.14. Status register (DAC_STAT) ............................................................................................................ 408
14. Inter-integrated circuit (I2C) interface ............................................................. 410
14.1. Introduction .................................................................................................................... 410
14.2. Main features .................................................................................................................. 410
14.3. Function description ........................................................................................................ 410
14.3.1. SDA and SCL lines .............................................................................................................................. 411
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14.3.2. Data validation ................................................................................................................................... 412
14.3.3. START and STOP condition ................................................................................................................. 412
14.3.4. Clock synchronization ........................................................................................................................ 412
14.3.5. Arbitration ......................................................................................................................................... 413
14.3.6. I2C communication flow .................................................................................................................... 413
14.3.7. Programming model .......................................................................................................................... 414
14.3.8. Packet error checking ........................................................................................................................ 424
14.3.9. SMBus support .................................................................................................................................. 424
14.3.10. Status, errors and interrupts ......................................................................................................... 425
14.4. I2C registers..................................................................................................................... 426
14.4.1. Control register 0 (I2C_CTL0) ............................................................................................................. 426
14.4.2. Control register 1 (I2C_CTL1) ............................................................................................................. 428
14.4.3. Slave address register 0 (I2C_SADDR0).............................................................................................. 429
14.4.4. Slave address register 1 (I2C_SADDR1).............................................................................................. 429
14.4.5. Transfer buffer register (I2C_DATA) ................................................................................................... 430
14.4.6. Transfer status register 0 (I2C_STAT0)................................................................................................ 430
14.4.7. Transfer status register 1 (I2C_STAT1)................................................................................................ 432
14.4.8. Clock configure register (I2C_CKCFG) ................................................................................................ 434
14.4.9. Rise time register (I2C_RT) ................................................................................................................ 434
14.4.10. SAM control and status register (I2C_SAMCS) of GD32F170xx and GD32F190xx devices ............ 435
15. Serial peripheral interface/Inter-IC sound(SPI/I2S) ........................................ 437
15.1. Introduction .................................................................................................................... 437
15.2. Main features .................................................................................................................. 437
15.2.1. SPI features ........................................................................................................................................ 437
15.2.2. I2S features ........................................................................................................................................ 438
15.3. SPI function description ................................................................................................... 439
15.3.1. Pin configuration (Single wire, default) ............................................................................................. 439
15.3.2. Pin configuration (Quad wire) for GD32F170xx and GD32F190xx devices ........................................ 441
15.3.3. SPI slave mode ................................................................................................................................... 442
15.3.4. SPI master mode ................................................................................................................................ 443
15.3.5. SPI quad wire operation in master mode for GD32F170xx and GD32F190xx devices ...................... 444
15.3.6. SPI simplex communication ............................................................................................................... 446
15.3.7. Data Rx and Tx procedures ................................................................................................................ 447
15.3.8. CRC calculation .................................................................................................................................. 447
15.3.9. Status flags and error flags ................................................................................................................ 448
15.3.10. Disabling the SPI ............................................................................................................................ 450
15.3.11. DMA requests ................................................................................................................................ 450
15.3.12. SPI interrupts ................................................................................................................................. 451
15.4. I2S function description ................................................................................................... 452
15.4.1. General description ........................................................................................................................... 452
15.4.2. Supported audio standards ............................................................................................................... 453
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15.4.3. Clock generator ................................................................................................................................. 460
15.4.4. Operation........................................................................................................................................... 463
15.4.5. DMA features ..................................................................................................................................... 467
15.5. SPI registers ..................................................................................................................... 467
15.5.1. Control register 0 (SPI_CTL0) ............................................................................................................. 467
15.5.2. Control register 1 (SPI_CTL1) ............................................................................................................. 469
15.5.3. Status register (SPI_STAT) .................................................................................................................. 470
15.5.4. Data register (SPI_DATA) .................................................................................................................... 471
15.5.5. CRC polynomial register (SPI_CRCPOLY) ............................................................................................ 471
15.5.6. Receive CRC register (SPI_RCRC) ....................................................................................................... 472
15.5.7. Transmit CRC register (SPI_TCRC) ...................................................................................................... 472
15.5.8. I2S control register (SPI_I2SCTL) ........................................................................................................ 473
15.5.9. I2S prescaler register (SPI_I2SPSC) .................................................................................................... 474
15.5.10. Quad wire control register (SPI_QCTL) of GD32F170xx and GD32F190xx devices ........................ 475
16. Comparator (CMP) ............................................................................................ 476
16.1. Introduction .................................................................................................................... 476
16.2. Main features .................................................................................................................. 476
16.3. Function description ........................................................................................................ 476
16.3.1. CMP clock and reset .......................................................................................................................... 478
16.3.2. CMP inputs and outputs .................................................................................................................... 478
16.3.3. CMP power mode .............................................................................................................................. 478
16.3.4. CMP hysteresis .................................................................................................................................. 478
16.3.5. CMP register write protection ........................................................................................................... 479
16.4. CMP registers .................................................................................................................. 479
16.4.1. Control/status register (CMP_CS) ...................................................................................................... 479
17. Universal synchronous asynchronous receiver transmitter (USART) ......... 486
17.1. Introduction .................................................................................................................... 486
17.2. Main features .................................................................................................................. 486
17.3. Function description ........................................................................................................ 488
17.3.1. USART transmitter ............................................................................................................................. 489
17.3.2. USART receiver .................................................................................................................................. 490
17.3.3. Reception errors ................................................................................................................................ 491
17.3.4. Baud rate generation ......................................................................................................................... 491
17.3.5. Auto baudrate detection ................................................................................................................... 492
17.3.6. Multi-processor communication ....................................................................................................... 492
17.3.7. ModBus communication ................................................................................................................... 492
17.3.8. LIN mode ........................................................................................................................................... 493
17.3.9. Half-duplex communication mode .................................................................................................... 493
17.3.10. Synchronous mode ........................................................................................................................ 494
17.3.11. Smartcard (ISO7816) mode ........................................................................................................... 494
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17.3.12. IrDA SIR ENDEC mode .................................................................................................................... 496
17.3.13. Hardware flow control ................................................................................................................... 498
17.3.14. DMA requests ................................................................................................................................ 499
17.3.15. Wakeup from Deep-sleep mode.................................................................................................... 500
17.3.16. USART interrupts ........................................................................................................................... 500
17.4. USART registers ............................................................................................................... 501
17.4.1. Control register 0 (USART_CTL0) ....................................................................................................... 501
17.4.2. Control register 1 (USART_CTL1) ....................................................................................................... 504
17.4.3. Control register 2 (USART_CTL2) ....................................................................................................... 506
17.4.4. Baud rate generator register (USART_BAUD) .................................................................................... 509
17.4.5. Prescaler and guard time configuration register (USART_GP) ........................................................... 510
17.4.6. Receiver timeout register (USART_RT) .............................................................................................. 511
17.4.7. Command register (USART_CMD) ..................................................................................................... 512
17.4.8. Status register (USART_STAT) ............................................................................................................ 512
17.4.9. Interrupt status clear register (USART_INTC) .................................................................................... 516
17.4.10. Receive data register (USART_RDATA) ........................................................................................... 518
17.4.11. Transmit data register (USART_TDATA) ......................................................................................... 518
18. Debug (DBG) ..................................................................................................... 520
18.1. Introduction .................................................................................................................... 520
18.2. Function description ........................................................................................................ 520
18.2.1. Debug support for power saving mode ............................................................................................. 520
18.2.2. Debug support for TIMER, I2C, RTC, WWDGT, FWDGT and CAN ....................................................... 520
18.3. DBG registers .................................................................................................................. 521
18.3.1. ID code register (DBG_ID) .................................................................................................................. 521
18.3.2. Control register 0(DBG_CTL0) ............................................................................................................ 521
18.3.3. Control register 1 (DBG_CTL1) ........................................................................................................... 525
19. Universal serial bus full-speed device interface (USBD)............................... 527
19.1. Introduction .................................................................................................................... 527
19.2. Main features .................................................................................................................. 528
19.2.1. Implementation ................................................................................................................................. 528
19.2.2. Clock .................................................................................................................................................. 528
19.2.3. Pin description ................................................................................................................................... 529
19.3. Function description ........................................................................................................ 529
19.3.1. Basic functional block ........................................................................................................................ 529
19.3.2. Buffer ................................................................................................................................................. 532
19.3.3. Endpoint ............................................................................................................................................ 533
19.3.4. Interrupt handling ............................................................................................................................. 535
19.3.5. Reset events ...................................................................................................................................... 536
19.3.6. Transfer procedure ............................................................................................................................ 537
19.3.7. Power management .......................................................................................................................... 540
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19.4. USB registers ................................................................................................................... 542
19.4.1. Control register (USBD_CTL) .............................................................................................................. 542
19.4.2. Interrupt flag register (USBD_INTF) ................................................................................................... 543
19.4.3. Status register (USBD_STAT) .............................................................................................................. 544
19.4.4. Device address register (USBD_DADDR) ............................................................................................ 545
19.4.5. Buffer address register (USBD_BADDR) ............................................................................................. 545
19.4.6. Endpoint n control/status register (USBD_EPxCS), n=[0..7] .............................................................. 546
19.4.7. Transmission buffer address register x (USBD_TADDRx) ................................................................... 547
19.4.8. Transmission byte count register x (USBD_TCNTx) ............................................................................ 548
19.4.9. Reception buffer address register x (USBD_RADDRx) ....................................................................... 548
19.4.10. Reception byte count register x (USBD_RCNTx) ............................................................................ 548
19.4.11. Sub-endpoint x registers (USBD_SEPx), n=[0..7] ........................................................................... 549
19.4.12. LPM control register (USBD_LPMCTL) ........................................................................................... 550
19.4.13. LPM interrupt flag register (USBD_LPMINTF) ................................................................................ 550
20. Real-time clock(RTC) ........................................................................................ 551
20.1. Introduction .................................................................................................................... 551
20.2. Main features .................................................................................................................. 551
20.3. Function description ........................................................................................................ 552
20.3.1. Block diagram .................................................................................................................................... 552
20.3.2. RTC pin ............................................................................................................................................... 553
20.3.3. Clock and prescalers .......................................................................................................................... 554
20.3.4. Real-time clock and calendar............................................................................................................. 554
20.3.5. Configurable and field maskable alarm ............................................................................................. 555
20.3.6. RTC initialization and configuration ................................................................................................... 555
20.3.7. Calendar reading ............................................................................................................................... 557
20.3.8. Resetting the RTC .............................................................................................................................. 558
20.3.9. RTC synchronization .......................................................................................................................... 558
20.3.10. RTC reference clock detection ....................................................................................................... 559
20.3.11. RTC smooth digital calibration ....................................................................................................... 560
20.3.12. Time-stamp function ..................................................................................................................... 562
20.3.13. Tamper detection .......................................................................................................................... 562
20.3.14. Calibration clock output ................................................................................................................ 563
20.3.15. Alarm output ................................................................................................................................. 564
20.3.16. RTC power saving mode management .......................................................................................... 564
20.3.17. RTC interrupts ................................................................................................................................ 564
20.4. RTC registers .................................................................................................................... 564
20.4.1. Time of day register (RTC_TIME) ....................................................................................................... 564
20.4.2. Date register (RTC_DATE) .................................................................................................................. 565
20.4.3. Control register (RTC_CTL) ................................................................................................................. 566
20.4.4. Status register (RTC_STAT) ................................................................................................................. 568
20.4.5. Time prescaler register (RTC_PSC) ..................................................................................................... 570
20.4.6. Alarm 0 Time and date register (RTC_ALRM0TD) .............................................................................. 570
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20.4.7. Write protection key register (RTC_WPK) .......................................................................................... 572
20.4.8. Sub second register (RTC_SS) ............................................................................................................ 572
20.4.9. Shift function control register (RTC_SHIFTCTL) ................................................................................. 572
20.4.10. Time of time stamp register (RTC_TTS) ......................................................................................... 573
20.4.11. Date of time stamp register (RTC_DTS) ......................................................................................... 574
20.4.12. Sub second of time stamp register (RTC_SSTS) ............................................................................. 575
20.4.13. High resolution frequency compensation registor (RTC_HRFC) .................................................... 575
20.4.14. Tamper register (RTC_TAMP) ......................................................................................................... 576
20.4.15. Alarm 0 sub second register (RTC_ALRM0SS) ............................................................................... 579
20.4.16. Backup register (RTC_BKPx)(x=0,1,2,3,4) ...................................................................................... 580
21. Touch sensing interface(TSI) ........................................................................... 581
21.1. Introduction .................................................................................................................... 581
21.2. Main features .................................................................................................................. 581
21.3. Function description ........................................................................................................ 581
21.3.1. TSI block diagram ............................................................................................................................... 581
21.3.2. Touch sensing technique overview .................................................................................................... 581
21.3.3. Charge transfer sequence .................................................................................................................. 582
21.3.4. Charge transfer sequence FSM .......................................................................................................... 585
21.3.5. Clock and duration time of states ...................................................................................................... 586
21.3.6. PIN mode control of TSI ..................................................................................................................... 587
21.3.7. ASW and hysteresis mode ................................................................................................................. 587
21.3.8. TSI operation flow ............................................................................................................................. 587
21.3.9. TSI flags and interrupts ...................................................................................................................... 587
21.3.10. TSI GPIOs ....................................................................................................................................... 588
21.4. TSI registers ..................................................................................................................... 588
21.4.1. Control register (TSI_CTL) .................................................................................................................. 588
21.4.2. Interrupt enable register (TSI_INTEN) ............................................................................................... 591
21.4.3. Interrupt flag clear register (TSI_INTC) .............................................................................................. 591
21.4.4. Interrupt flag register (TSI_INTF) ....................................................................................................... 592
21.4.5. Pin hysteresis mode register (TSI_PHM) ............................................................................................ 592
21.4.6. Analog switch register (TSI_ASW) ...................................................................................................... 593
21.4.7. Sample configuration register (TSI_SAMPCFG) ................................................................................. 593
21.4.8. Channel configuration register (TSI_CHCFG) ..................................................................................... 594
21.4.9. Group control register (TSI_GCTL) ..................................................................................................... 594
21.4.10. Group x cycle number registers (TSI_GxCYCN) (x= 0..5) ................................................................ 595
22. HDMI-CEC controller(HDMI-CEC) .................................................................... 596
22.1. Introduction .................................................................................................................... 596
22.2. Main features .................................................................................................................. 596
22.3. Function description ........................................................................................................ 596
22.3.1. CEC bus pin ........................................................................................................................................ 596
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22.3.2. Message description .......................................................................................................................... 597
22.3.3. Bit timing description ........................................................................................................................ 598
22.3.4. Arbitration ......................................................................................................................................... 599
22.3.5. SFT option bit description .................................................................................................................. 600
22.3.6. Error definition .................................................................................................................................. 600
22.3.7. HDMI-CEC interrupt ........................................................................................................................... 603
22.4. HDMI-CEC registers ......................................................................................................... 604
22.4.1. Control register (CEC_CTL) ................................................................................................................. 604
22.4.2. Configuration register (CEC_CFG) ...................................................................................................... 605
22.4.3. Transmit data register (CEC_TDATA) .................................................................................................. 607
22.4.4. Receive data register (CEC_RDATA) ................................................................................................... 607
22.4.5. Interrupt Flag Register (CEC_INTF) .................................................................................................... 608
22.4.6. Interrupt enable register (CEC_INTEN) .............................................................................................. 609
23. Segment LCD controller (SLCD) ...................................................................... 612
23.1. Introduction .................................................................................................................... 612
23.2. Main features .................................................................................................................. 612
23.3. Function description ........................................................................................................ 612
23.3.1. SLCD Architecture .............................................................................................................................. 612
23.3.2. Clock generator ................................................................................................................................. 613
23.3.3. Blink control ....................................................................................................................................... 614
23.3.4. SEG/COM Driver ................................................................................................................................ 614
23.3.5. Double buffer memory ...................................................................................................................... 617
23.3.6. ANALOG matrix .................................................................................................................................. 617
23.4. SLCD registers .................................................................................................................. 618
23.4.1. Control register (SLCD_CTL) ............................................................................................................... 618
23.4.2. Configuration register (SLCD_CFG) .................................................................................................... 619
23.4.3. Status flag register (SLCD_STAT) ........................................................................................................ 621
23.4.4. Status flag clear register (SLCD_STATC).............................................................................................. 622
23.4.5. Display data registers (SLCD_DATAx, x=0~7) ...................................................................................... 623
24. Operational amplifiers (OPA)/ Programmable current and voltage reference
(IVREF) ........................................................................................................................ 624
24.1. Operational amplifiers (OPA) ........................................................................................... 624
24.1.1. Introduction ....................................................................................................................................... 624
24.1.2. Main features .................................................................................................................................... 624
24.1.3. Function description .......................................................................................................................... 624
24.1.4. OPA register ....................................................................................................................................... 627
24.2. Programmable Current and Voltage Reference (IVREF) .................................................... 631
24.2.1. Introduction ....................................................................................................................................... 631
24.2.2. Main features .................................................................................................................................... 631
24.2.3. Function description .......................................................................................................................... 632
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24.2.4. IVREF registers ................................................................................................................................... 632
25. Controller area network (CAN) ........................................................................ 634
25.1. Introduction .................................................................................................................... 634
25.2. Main features .................................................................................................................. 634
25.3. Function description ........................................................................................................ 635
25.3.1. Working mode ................................................................................................................................... 635
25.3.2. Communication modes ..................................................................................................................... 636
25.3.3. Data transmission .............................................................................................................................. 637
25.3.4. Data reception ................................................................................................................................... 639
25.3.5. Filtering Function ............................................................................................................................... 640
25.3.6. Time-triggered communication ......................................................................................................... 643
25.3.7. Communication parameters .............................................................................................................. 643
25.3.8. Error flags .......................................................................................................................................... 645
25.3.9. CAN interrupts ................................................................................................................................... 646
25.3.10. CAN PHY mode .............................................................................................................................. 647
25.4. CAN registers ................................................................................................................... 647
25.4.1. Control register (CAN_CTL) ................................................................................................................ 647
25.4.2. Status register (CAN_STAT) ................................................................................................................ 649
25.4.3. Transmit status register (CAN_TSTAT) ................................................................................................ 650
25.4.4. Receive message FIFO0 register (CAN_RFIFO0) ................................................................................. 652
25.4.5. Receive message FIFO1 register (CAN_RFIFO1) ................................................................................. 653
25.4.6. Interrupt enable register (CAN_INTEN) ............................................................................................. 653
25.4.7. Error register (CAN_ERR) ................................................................................................................... 655
25.4.8. Bit timing register (CAN_BT) .............................................................................................................. 656
25.4.9. Transmit mailbox identifier register (CAN_TMIx) (x=0..2) ................................................................. 657
25.4.10. Transmit mailbox property register (CAN_TMPx) (x=0..2) ............................................................. 658
25.4.11. Transmit mailbox data0 register (CAN_TMDATA0x) (x=0..2) ......................................................... 658
25.4.12. Transmit mailbox data1 register (CAN_TMDATA1x) (x=0..2) ......................................................... 659
25.4.13. Receive FIFO mailbox identifier register (CAN_RFIFOMIx) (x=0..1) ............................................... 659
25.4.14. Receive FIFO mailbox property register (CAN_RFIFOMPx) (x=0..1) ............................................... 660
25.4.15. Receive FIFO mailbox data0 register (CAN_RFIFOMDATA0x) (x=0..1) ........................................... 661
25.4.16. Receive FIFO mailbox data1 register (CAN_RFIFOMDATA1x) (x=0..1) ........................................... 661
25.4.17. Filter control register (CAN_FCTL) ................................................................................................. 662
25.4.18. Filter mode configuration register (CAN_FMCFG) ......................................................................... 662
25.4.19. Filter scale configuration register (CAN_FSCFG) ............................................................................ 663
25.4.20. Filter associated FIFO register (CAN_FAFIFO) ................................................................................ 663
25.4.21. Filter working register (CAN_FW) .................................................................................................. 664
25.4.22. Filter x data y register (CAN_FxDATAy) (x=0..27, y=0..1) ............................................................... 664
25.4.23. PHY control register (CAN_PHYCTL) .............................................................................................. 665
26. Revision history ................................................................................................ 666
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List of Figures
Figure 1-1. Cortex™-M3 block diagram .............................................................................................. 2
Figure 1-2. Series system architecture of GD32F130xx and GD32F150xx devices ................ 3
Figure 1-3. Series system architecture of GD32F170xx and GD32F190xx devices ................ 4
Figure 1-4. Memory map of GD32F130xx and GD32F150xx devices........................................... 6
Figure 1-5. Memory map of GD32F170xx and GD32F190xx devices........................................... 7
Figure 2-1. Power supply overview of GD32F130xx and GD32F150xx devices ..................... 22
Figure 2-2. Power supply overview of GD32F170xx and GD32F190xx devices ..................... 23
Figure 2-3. Waveform of the power reset ......................................................................................... 25
Figure 2-4. Waveform of LVD threshold ............................................................................................ 26
Figure 3-1. Proccess of page erase operation ................................................................................ 36
Figure 3-2. Process of the mass erase operation .......................................................................... 37
Figure 3-3. Process of the word programming operation ............................................................ 38
Figure 4-1. The system reset circuit .................................................................................................. 51
Figure 4-2. Clock tree of GD32F130xx and GD32F150xx devices .............................................. 52
Figure 4-3. Clock tree of GD32F170xx and GD32F190xx devices .............................................. 53
Figure 5-1. Basic structure of a standard I/O port bit ................................................................. 102
Figure 5-2. Input floating/pull up/pull down configurations ...................................................... 104
Figure 5-3. Output configuration ...................................................................................................... 104
Figure 5-4. High impedance-analog configuration ...................................................................... 105
Figure 5-5. Alternate function configuration ................................................................................. 106
Figure 6-1.Block Diagram of CRC Calculation Unit ..................................................................... 120
Figure 7-1. Block diagram of EXTI. .................................................................................................. 129
Figure 8-1. DMA interrupt generation logic .................................................................................... 139
Figure 8-2. DMA request mapping .................................................................................................... 140
Figure 9-1. Advanced timer block diagram .................................................................................... 149
Figure 9-2. Counter timing diagram with prescaler division change from 1 to 2 ................ 150
Figure 9-3. Counter timing diagram with prescaler division change from 1 to 4 ................ 150
Figure 9-4. Counter timing diagram, internal clock divided by 1 ............................................. 151
Figure 9-5. Counter timing diagram, internal clock divided by 2 ............................................. 152
Figure 9-6. Counter timing diagram, internal clock divided by 4 ............................................. 152
Figure 9-7. Counter timing diagram, internal clock divided by N ............................................ 153
Figure 9-8. Counter timing diagram, update event when ARSE=0 .......................................... 153
Figure 9-9. Counter timing diagram, update event when ARSE=1 .......................................... 154
Figure 9-10. Counter timing diagram, internal clock divided by 1 ........................................... 155
Figure 9-11. Counter timing diagram, internal clock divided by 2 ........................................... 156
Figure 9-12. Counter timing diagram, internal clock divided by 4 ........................................... 156
Figure 9-13. Counter timing diagram, internal clock divided by N .......................................... 157
Figure 9-14. Counter timing diagram, update event when repetition counter is not used 157
Figure 9-15. Counter timing diagram, internal clock divided by 1, TIMERx_CAR = 0x5 .... 158
Figure 9-16. Counter timing diagram, internal clock divided by 2 ........................................... 159
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Figure 9-17. Counter timing diagram, internal clock divided by 4, TIMERx_CAR=0x63 .... 159
Figure 9-18. Counter timing diagram, internal clock divided by N .......................................... 160
Figure 9-19. Counter timing diagram, update event with ARSE=1(counter underflow) ..... 160
Figure 9-20. Counter timing diagram, Update event with ARSE=1 (counter overflow) ...... 161
Figure 9-21. Update rate examples depending on mode and TIMERx_CREP ...................... 162
Figure 9-22. Control circuit in normal mode, internal clock divided by 1 .............................. 162
Figure 9-23. Capture/compare channel (example: channel 0 input stage) ............................ 164
Figure 9-24. Capture/compare channel 0 main circuit ................................................................ 165
Figure 9-25. Output stage of capture/compare channel (channel 0 to 2) ............................... 165
Figure 9-26. Output stage of capture/compare channel (channel 3) ....................................... 166
Figure 9-27. Output compare toggle mode, toggle on CH0_O .................................................. 167
Figure 9-28. Output compare PWM mode 0 on CH0_O, upcounting mode ........................... 168
Figure 9-29. Output compare PWM mode 0 on CH0_O, center-aligned counting mode .... 168
Figure 9-30. Complementary output with dead-time insertion. ................................................ 169
Figure 9-31. Dead-time waveforms with delay greater than the negative pulse .................. 169
Figure 9-32. Dead-time waveforms with delay greater than the positive pulse ................... 170
Figure 9-33. Output behavior in response to a break（The break input is acting on high level）
........................................................................................................................................................... 170
Figure 9-34. Single pulse mode ........................................................................................................ 172
Figure 9-35. Example of counter operation in encoder interface mode ................................. 173
Figure 9-36. Example of encoder interface mode with CI0FE0 polarity inverted ................. 173
Figure 9-37. Control circuit in restart mode................................................................................... 174
Figure 9-38. Control circuit in pause mode ................................................................................... 174
Figure 9-39. Control circuit in event mode..................................................................................... 175
Figure 9-40. TIMER0 Master/Slave mode timer example ............................................................ 175
Figure 9-41. Triggering TIMER0 with Enable of TIMER1 ............................................................. 177
Figure 9-42. Triggering TIMER0 with update of TIMER1 ............................................................. 177
Figure 9-43. Gating TIMER0 with enable of TIMER1 .................................................................... 178
Figure 9-44. Gating TIMER0 with O0CPREof TIMER1 ................................................................. 178
Figure 9-45. Triggering TIMER0 and TIMER1 with TIMER1’s CI0 input .................................. 179
Figure 9-46. General timer block diagram (TIMER1 and TIMER2) ............................................ 205
Figure 9-47. Counter timing diagram with prescaler division change from 1 to 2 .............. 206
Figure 9-48. Counter timing diagram with prescaler division change from 1 to 4 .............. 206
Figure 9-49. Counter timing diagram, internal clock divided by 1 ........................................... 207
Figure 9-50. Counter timing diagram, internal clock divided by 2 ........................................... 208
Figure 9-51. Counter timing diagram, internal clock divided by 4 ........................................... 208
Figure 9-52. Counter timing diagram, internal clock divided by N .......................................... 209
Figure 9-53. Counter timing diagram, update event when ARSE=0 ........................................ 209
Figure 9-54. Counter timing diagram, update event when ARSE=1 ........................................ 210
Figure 9-55. Counter timing diagram, internal clock divided by 1 ........................................... 211
Figure 9-56. Counter timing diagram, internal clock divided by 2 ........................................... 211
Figure 9-57. Counter timing diagram, internal clock divided by 4 ........................................... 212
Figure 9-58. Counter timing diagram, internal clock divided by N .......................................... 212
Figure 9-59. Counter timing diagram, update event when counter is not used ................... 213
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Figure 9-60. Counter timing diagram, internal clock divided by 1, TIMERx_CAR = 0x5 .... 214
Figure 9-61. Counter timing diagram, internal clock divided by 2 ........................................... 214
Figure 9-62. Counter timing diagram, internal clock divided by 4, TIMERx_CAR=0x63 .... 215
Figure 9-63. Counter timing diagram, internal clock divided by N .......................................... 215
Figure 9-64. Counter timing diagram, update event with ARSE=1(counter underflow) ..... 216
Figure 9-65. Counter timing diagram, Update event with ARSE=1 (counter overflow) ...... 216
Figure 9-66. Control circuit in normal mode, internal clock divided by 1 .............................. 217
Figure 9-67. Capture/compare channel (example: channel 0 input stage) ............................ 219
Figure 9-68. Capture/compare channel 0 main circuit ................................................................ 220
Figure 9-69. Output stage of capture/compare channel (channel 0) ....................................... 220
Figure 9-70. Output compare toggle mode, toggle on CH0_O .................................................. 222
Figure 9-71. Output compare PWM mode 0 on CH0_O, upcounting mode ........................... 222
Figure 9-72. Output compare PWM mode 0 on CH0_O, center-aligned counting mode .... 223
Figure 9-73. Single pulse mode ........................................................................................................ 224
Figure 9-74. Example of counter operation in encoder interface mode ................................. 225
Figure 9-75. Example of encoder interface mode with CI0FE0 polarity inverted ................. 226
Figure 9-76. Control circuit in restart mode................................................................................... 226
Figure 9-77. Control circuit in pause mode ................................................................................... 227
Figure 9-78. Control circuit in event mode..................................................................................... 227
Figure 9-79. Master/Slave mode timer example ............................................................................ 228
Figure 9-80. General timer block diagram (TIMER5) ................................................................... 250
Figure 9-81. Counter timing diagram with prescaler division change from 1 to 2 .............. 251
Figure 9-82. Counter timing diagram with prescaler division change from 1 to 4 .............. 251
Figure 9-83. Control circuit in normal mode, internal clock divided by 1 .............................. 252
Figure 9-84. General timer block diagram (TIMER13) ................................................................. 258
Figure 9-85. Counter timing diagram with prescaler division change from 1 to 2 .............. 259
Figure 9-86. Counter timing diagram with prescaler division change from 1 to 4 .............. 259
Figure 9-87. Counter timing diagram, internal clock divided by 1 ........................................... 260
Figure 9-88. Counter timing diagram, internal clock divided by 2 ........................................... 261
Figure 9-89. Counter timing diagram, internal clock divided by 4 ........................................... 261
Figure 9-90. Counter timing diagram, internal clock divided by N .......................................... 262
Figure 9-91. Counter timing diagram, update event when ARSE=0 ........................................ 262
Figure 9-92. Counter timing diagram, update event when ARSE=1 ........................................ 263
Figure 9-93. Control circuit in normal mode, internal clock divided by 1 .............................. 264
Figure 9-94. Capture/compare channel (example: input stage) ............................................... 265
Figure 9-95. Capture/compare channel 0 main circuit ................................................................ 266
Figure 9-96. Output stage of capture/compare channel ............................................................. 266
Figure 9-97. Output compare toggle mode, toggle on CH0_O .................................................. 268
Figure 9-98. Output compare PWM mode 0 on CH0_O, upcounting mode ........................... 268
Figure 9-99. Output compare PWM mode 0 on CH0_O, center-aligned counting mode .... 269
Figure 9-100. Gereral timer block diagram (TIMER14) ................................................................ 280
Figure 9-101. Counter timing diagram with prescaler division change from 1 to 2 ............ 281
Figure 9-102. Counter timing diagram with prescaler division change from 1 to 4 ............ 281
Figure 9-103. Counter timing diagram, internal clock divided by 1 ........................................ 282
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Figure 9-104. Counter timing diagram, internal clock divided by 2 ........................................ 283
Figure 9-105. Counter timing diagram, internal clock divided by 4 ........................................ 283
Figure 9-106. Counter timing diagram, internal clock divided by N ........................................ 284
Figure 9-107. Counter timing diagram, update event when ARSE=0 ...................................... 284
Figure 9-108. Counter timing diagram, update event when ARSE=1 ...................................... 285
Figure 9-109. Update rate examples depending on mode and TIMERx_CREP .................... 285
Figure 9-110. Control circuit in normal mode, internal clock divided by 1 ............................ 286
Figure 9-111. Capture/compare channel (example: channel 0 input stage) .......................... 287
Figure 9-112. Capture/compare channel 0 main circuit .............................................................. 288
Figure 9-113. Output stage of capture/compare channel (channel 0) ..................................... 288
Figure 9-114. Output stage of capture/compare channel (channel 1) ..................................... 289
Figure 9-115. Output compare toggle mode, toggle onCH0_O ................................................. 291
Figure 9-116. Output compare PWM mode 0 on CH0_O, upcounting mode ......................... 291
Figure 9-117. Output compare PWM mode 0 on CH0_O, center-aligned counting mode .. 292
Figure 9-118. Complementary output with dead-time insertion. .............................................. 293
Figure 9-119. Dead-time waveforms with delay greater than the negative pulse ................ 293
Figure 9-120. Dead-time waveforms with delay greater than the positive pulse ................. 293
Figure 9-121. Output behavior in response to a break（The break input is acting on high
level） .............................................................................................................................................. 294
Figure 9-122. Single pulse mode ...................................................................................................... 295
Figure 9-123. Control circuit in restart mode ................................................................................ 296
Figure 9-124. Control circuit in pause mode ................................................................................. 296
Figure 9-125. Control circuit in event mode .................................................................................. 297
Figure 9-126. TIMER14 Master/Slave mode timer example........................................................ 298
Figure 9-127. Triggering TIMER14 with Enable of TIMER1 ........................................................ 299
Figure 9-128. Triggering TIMER14 with update of TIMER1 ........................................................ 299
Figure 9-129. Gating TIMER14 with enable of TIMER1 ............................................................... 300
Figure 9-130. Gating TIMER14 with O0CPREof TIMER1 ............................................................. 300
Figure 9-131. Triggering TIMER14 and TIMER1 with TIMER1’s CI0 input .............................. 301
Figure 9-132. Gereral timer block diagram (TIMER15/16) .......................................................... 322
Figure 9-133. Counter timing diagram with prescaler division change from 1 to 2 ............ 322
Figure 9-134. Counter timing diagram with prescaler division change from 1 to 4 ............ 323
Figure 9-135. Counter timing diagram, internal clock divided by 1 ........................................ 324
Figure 9-136. Counter timing diagram, internal clock divided by 2 ........................................ 324
Figure 9-137. Counter timing diagram, internal clock divided by 4 ........................................ 325
Figure 9-138. Counter timing diagram, internal clock divided by N ........................................ 325
Figure 9-139. Counter timing diagram, update event when ARSE=0 ...................................... 326
Figure 9-140. Counter timing diagram, update event when ARSE=1 ...................................... 326
Figure 9-141. Update rate examples depending on mode and TIMERx_CREP .................... 327
Figure 9-142. Control circuit in normal mode, internal clock divided by 1 ........................... 328
Figure 9-143. Capture/compare channel (example: channel 0 input stage) .......................... 329
Figure 9-144. Capture/compare channel 0 main circuit .............................................................. 329
Figure 9-145. Output stage of capture/compare channel (channel 0) ..................................... 330
Figure 9-146. Output compare toggle mode, toggle on CH0_O ............................................... 331
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Figure 9-147. Output compare PWM mode 0 on CH0_O, upcounting mode ......................... 332
Figure 9-148. Output compare PWM mode 0 on CH0_O, center-aligned counting mode . 332
Figure 9-149. Complementary output with dead-time insertion. .............................................. 333
Figure 9-150. Dead-time waveforms with delay greater than the negative pulse ................ 333
Figure 9-151. Dead-time waveforms with delay greater than the positive pulse ................. 334
Figure 9-152. Output behavior in response to a break（The break input is acting on high
level） .............................................................................................................................................. 335
Figure 9-153. Single pulse mode ...................................................................................................... 336
Figure 10-1. IFRR output timechart 1 .............................................................................................. 352
Figure 10-2. IFRR output timechart 2 .............................................................................................. 353
Figure 10-3. IFRR output timechart 3 .............................................................................................. 353
Figure 11-1. Free watchdog timer block diagram ......................................................................... 355
Figure 11-2. Window watchdog timer block diagram .................................................................. 360
Figure 11-3. Window watchdog timer timing diagram ................................................................ 361
Figure 12-1. ADC module block diagram of GD32F130xx and GD32F150xx devices ......... 366
Figure 12-2. ADC module block diagram of GD32F170xx and GD32F190xx devices ......... 367
Figure 12-3. Single conversion mode .............................................................................................. 369
Figure 12-4. Continuous conversion mode, scan disable ......................................................... 370
Figure 12-5. Continuous conversion mode, scan enable .......................................................... 370
Figure 12-6. Scan conversion mode ................................................................................................ 371
Figure 12-7. Discontinuous conversion mode .............................................................................. 372
Figure 12-8. Data alignment of 12-bit resolution .......................................................................... 373
Figure 12-9. 20-bit to 16-bit result truncation ................................................................................ 377
Figure 12-10. Numerical example with 5-bits shift and rounding ............................................ 377
Figure 13-1. DAC block diagram ....................................................................................................... 394
Figure 14-1. I2C module block diagram .......................................................................................... 411
Figure 14-2. Data validation ............................................................................................................... 412
Figure 14-3. START and STOP condition ........................................................................................ 412
Figure 14-4. Clock synchronization ................................................................................................. 413
Figure 14-5. SDA Line arbitration ..................................................................................................... 413
Figure 14-6. I2C communication flow with 7-bit address. .......................................................... 414
Figure 14-7. I2C communication flow with 10-bit address. ........................................................ 414
Figure 14-8. Programming model for slave transmitting ........................................................... 416
Figure 14-9. Programming model for slave receiving ................................................................. 417
Figure 14-10. Programming model for master transmitting ...................................................... 419
Figure 14-11. Programming model for master receiving using Solution A ........................... 421
Figure 14-12. Programming model for master receiving using Solution B ........................... 423
Figure 15-1. Single master/ single slave application ................................................................... 439
Figure 15-2. SPI data clock timing diagram ................................................................................... 441
Figure 15-3. SPI data clock timing diagram in quad wire mode (CKPL=1, CKPH=1) .......... 442
Figure 15-4. Transmission using DMA ............................................................................................ 451
Figure 15-5. Reception using DMA .................................................................................................. 451
Figure 15-6. I2S block diagram ......................................................................................................... 452
Figure 15-7. I2S Phillips standard timing diagram (DTLEN=00, CHLEN=0, CKPL=0) ......... 453
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Figure 15-8. I2S Phillips standard timing diagram (DTLEN=00, CHLEN=0, CKPL=1) ......... 453
Figure 15-9. I2S Phillips standard timing diagram (DTLEN=10, CHLEN=1, CKPL=0) ......... 454
Figure 15-10. I2S Phillips standard timing diagram (DTLEN=10, CHLEN=1, CKPL=1) ....... 454
Figure 15-11. I2S Phillips standard timing diagram (DTLEN=01, CHLEN=1, CKPL=0) ....... 454
Figure 15-12. I2S Phillips standard timing diagram (DTLEN=01, CHLEN=1, CKPL=1) ....... 454
Figure 15-13. I2S Phillips standard timing diagram (DTLEN=00, CHLEN=1, CKPL=0) ....... 454
Figure 15-14. I2S Phillips standard timing diagram (DTLEN=00, CHLEN=1, CKPL=1) ....... 455
Figure 15-15. MSB justified standard timing diagram (DTLEN=00, CHLEN=0, CKPL=0) ... 455
Figure 15-16. MSB justified standard timing diagram (DTLEN=00, CHLEN=0, CKPL=1) ... 455
Figure 15-17. MSB justified standard timing diagram (DTLEN=10, CHLEN=1, CKPL=0) ... 455
Figure 15-18. MSB justified standard timing diagram (DTLEN=10, CHLEN=1, CKPL=1) ... 455
Figure 15-19. MSB justified standard timing diagram (DTLEN=01, CHLEN=1, CKPL=0) ... 456
Figure 15-20. MSB justified standard timing diagram (DTLEN=01, CHLEN=1, CKPL=1) ... 456
Figure 15-21. MSB justified standard timing diagram (DTLEN=00, CHLEN=1, CKPL=0) ... 456
Figure 15-22. MSB justified standard timing diagram (DTLEN=00, CHLEN=1, CKPL=1) ... 456
Figure 15-23. LSB justified standard timing diagram (DTLEN=01, CHLEN=1, CKPL=0) .... 456
Figure 15-24. LSB justified standard timing diagram (DTLEN=01, CHLEN=1, CKPL=1) .... 456
Figure 15-25. LSB justified standard timing diagram (DTLEN=00, CHLEN=1, CKPL=0) .... 457
Figure 15-26. LSB justified standard timing diagram (DTLEN=00, CHLEN=1, CKPL=1) .... 457
Figure 15-27. PCM standard short frame synchronization mode timing diagram (DTLEN=00,
CHLEN=0, CKPL=0) ...................................................................................................................... 457
Figure 15-28. PCM standard short frame synchronization mode timing diagram (DTLEN=00,
CHLEN=0, CKPL=1) ...................................................................................................................... 457
Figure 15-29. PCM standard short frame synchronization mode timing diagram (DTLEN=10,
CHLEN=1, CKPL=0) ...................................................................................................................... 458
Figure 15-30. PCM standard short frame synchronization mode timing diagram (DTLEN=10,
CHLEN=1, CKPL=1) ...................................................................................................................... 458
Figure 15-31. PCM standard short frame synchronization mode timing diagram (DTLEN=01,
CHLEN=1, CKPL=0) ...................................................................................................................... 458
Figure 15-32. PCM standard short frame synchronization mode timing diagram (DTLEN=01,
CHLEN=1, CKPL=1) ...................................................................................................................... 458
Figure 15-33. PCM standard short frame synchronization mode timing diagram (DTLEN=00,
CHLEN=1, CKPL=0) ...................................................................................................................... 458
Figure 15-34. PCM standard short frame synchronization mode timing diagram (DTLEN=00,
CHLEN=1, CKPL=1) ...................................................................................................................... 458
Figure 15-35. PCM standard long frame synchronization mode timing diagram (DTLEN=00,
CHLEN=0, CKPL=0) ...................................................................................................................... 459
Figure 15-36. PCM standard long frame synchronization mode timing diagram (DTLEN=00,
CHLEN=0, CKPL=1) ...................................................................................................................... 459
Figure 15-37. PCM standard long frame synchronization mode timing diagram (DTLEN=10,
CHLEN=1, CKPL=0) ...................................................................................................................... 459
Figure 15-38. PCM standard long frame synchronization mode timing diagram (DTLEN=10,
CHLEN=1, CKPL=1) ...................................................................................................................... 459
Figure 15-39. PCM standard long frame synchronization mode timing diagram (DTLEN=01,
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21
CHLEN=1, CKPL=0) ...................................................................................................................... 459
Figure 15-40. PCM standard long frame synchronization mode timing diagram (DTLEN=01,
CHLEN=1, CKPL=1) ...................................................................................................................... 459
Figure 15-41. PCM standard long frame synchronization mode timing diagram (DTLEN=00,
CHLEN=1, CKPL=0) ...................................................................................................................... 460
Figure 15-42. PCM standard long frame synchronization mode timing diagram (DTLEN=00,
CHLEN=1, CKPL=1) ...................................................................................................................... 460
Figure 15-43. Block diagram of I2S clock generator ................................................................... 460
Figure 16-1. CMP block diagram of GD32F130xx and GD32F150xx devices ........................ 477
Figure 16-2. CMP block diagram of GD32F170xx and GD32F190xx devices ........................ 477
Figure 17-1. USART module block diagram................................................................................... 489
Figure 17-2. USART character frame (9 bits data and 1 stop bit) ............................................ 490
Figure 17-3. Frame error detection and break frame detection in LIN mode ........................ 493
Figure 17-4. Example of USART in synchronous mode ............................................................. 494
Figure 17-5. 8-bit format USART synchronous waveform (CLEN=1) ...................................... 494
Figure 17-6. ISO7816-3 frame format ............................................................................................... 495
Figure 17-7. IrDA SIR ENDEC module ............................................................................................. 497
Figure 17-8. IrDA data modulation ................................................................................................... 498
Figure 17-9. Hardware flow control between two USARTs ........................................................ 498
Figure 17-10. Hardware flow control................................................................................................ 499
Figure 17-11. USART interrupt mapping diagram ........................................................................ 501
Figure 19-1. USB peripheral block diagram ................................................................................... 530
Figure 19-2. An example with buffer descriptor table usage (USBD_BADDR = 0) .............. 533
Figure 19-3 .USB transaction and the interrupt event ................................................................ 538
Figure 20-1.Block diagram of RTC ................................................................................................... 552
Figure 21-1. Block diagram of TSI module ..................................................................................... 581
Figure 21-2. Block diagram of Sample pin and Channel Pin ..................................................... 582
Figure 21-3. Voltage of a sample pin during charge-transfer sequence ................................ 584
Figure 21-4. FSM flow of a charge-transfer sequence ................................................................ 585
Figure 22-1. HDMI-CEC Controller Block Diagram ....................................................................... 597
Figure 23-1. SLCD Block Diagram .................................................................................................... 613
Figure 24-1. OPA0 Signal Route ........................................................................................................ 625
Figure 24-2. OPA1 Signal Route ........................................................................................................ 625
Figure 24-3. OPA2 Signal Route ........................................................................................................ 625
Figure 25-1. CAN module block diagram ........................................................................................ 635
Figure 25-2. Transmission register .................................................................................................. 637
Figure 25-3. State of transmission mailbox ................................................................................... 638
Figure 25-4. Reception register ......................................................................................................... 639
Figure 25-5. 32-bit filter ....................................................................................................................... 640
Figure 25-6. 16-bit filter ....................................................................................................................... 641
Figure 25-7. 32-bit mask mode filter ................................................................................................ 641
Figure 25-8. 32-bit list mode filter ..................................................................................................... 641
Figure 25-9. 32-bit filter number ....................................................................................................... 641
Figure 25-10. Filtering index .............................................................................................................. 642
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Figure 25-11. The bit time ................................................................................................................... 644
Figure 25-12. CAN PHY connection ................................................................................................. 647
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List of Tables
Table 1-1. Flash module organization ................................................................................................. 9
Table 1-2. Flash module organization ................................................................................................. 9
Table 1-3. Boot modes........................................................................................................................... 10
Table 2-1. Power saving mode summary .......................................................................................... 28
Table 3-1. Base address and size for flash memory ...................................................................... 34
Table 3-2 Base address and size for flash memory ....................................................................... 34
Table 3-3. Option byte ............................................................................................................................ 40
Table 3-4. OB_WP bit for pages protected ....................................................................................... 41
Table 4-1. Clock source select ............................................................................................................ 57
Table 4-2. Clock source select ............................................................................................................ 57
Table 4-3. Core domain voltage selected in Deep-sleep mode - ................................................ 58
Table 4-4. Core domain voltage selected in Deep-sleep mode - ................................................ 58
Table 5-1. GPIO configuration table ................................................................................................. 102
Table 7-1. NVIC exception types in Cotrex-M3 .............................................................................. 125
Table 7-2. Interrupt vector table of GD32F130xx and GD32F150xx devices ......................... 125
Table 7-3. Interrupt vector table of GD32F170xx and GD32F190xx devices ......................... 126
Table 7-4. EXTI source of GD32F130xx and GD32F150xx devices .......................................... 130
Table 7-5. EXTI source of GD32F170xx and GD32F190xx devices .......................................... 131
Table 8-1. DMA transfer operations .................................................................................................. 137
Table 8-2. DMA interrupt event .......................................................................................................... 138
Table 8-3. Summary of DMA requests for each channel ............................................................ 141
Table 9-1. Counting direction versus encoder signals ............................................................... 172
Table 9-2. Counting direction versus encoder signals ............................................................... 225
Table 11-1. Min/max FWDGT timeout period at 40 kHz (IRC40K) ............................................. 356
Table 11-2. Min-max timeout value at 36 MHz (fPCLK1) ............................................................. 362
Table 12-1. ADC internal signals ....................................................................................................... 367
Table 12-2. ADC pins definition of GD32F130xx and GD32F150xx devices .......................... 367
Table 12-3. ADC pins definition of GD32F170xx and GD32F190xx devices .......................... 367
Table 12-4. External trigger for regular channels of ADC .......................................................... 373
Table 12-5. External trigger for inserted channels of ADC ........................................................ 374
Table 12-6. tSAR timings depending on resolution ........................................................................ 376
Table 12-7. Maximum output results vs N and M. Grayed values indicates truncation ..... 378
Table 13-1. DAC pin .............................................................................................................................. 394
Table 13-2. External triggers of DAC ............................................................................................... 397
Table 14-1. Definition of I2C-bus terminology ............................................................................... 411
Table 14-2. Event status flags ............................................................................................................ 426
Table 14-3. I2C error flags ................................................................................................................... 426
Table 15-1. SPI interrupt requests .................................................................................................... 451
Table 15-2. I2S bitrate calculation formulas ................................................................................... 460
Table 15-3. Audio sampling frequency calculation formulas .................................................... 461
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Table 15-4. Audio sampling frequency configuration and precision ...................................... 461
Table 15-5. Direction of I2S interface signals for each operation mode ................................ 463
Table 15-6. I2S interrupt ...................................................................................................................... 464
Table 17-1. USART important pins description ............................................................................. 488
Table 17-2. Stop bits configuration .................................................................................................. 490
Table 17-3. USART interrupt requests ............................................................................................. 500
Table 19-1. GD32F150xx USB implementation ............................................................................. 528
Table 19-2. GD32F150xx USB signal pinouts ................................................................................ 529
Table 19-3. Double-buffering buffer flag definition ...................................................................... 534
Table 19-4. Double buffer usage ....................................................................................................... 534
Table 19-5. Reception status encoding .......................................................................................... 547
Table 19-6. Endpoint type encoding ................................................................................................ 547
Table 19-7. Endpoint kind meaning ................................................................................................. 547
Table 19-8. Transmission status encoding .................................................................................... 547
Table 19-9. Sub-endpoints status ..................................................................................................... 549
Table 21-1. Pin and analog switch state in a charge-transfer sequence ................................ 583
Table 21-2. Duration time of Extend Charge state in each cycle .............................................. 586
Table 21-3. TSI errors and flags ........................................................................................................ 587
Table 21-4. TSI pins .............................................................................................................................. 588
Table 22-1. Data Bit Timing Parameter Table ................................................................................ 598
Table 22-2. Error Handling Timing Parameter Table ................................................................... 602
Table 22-3. TERR Timing Parameter Table .................................................................................... 603
Table 23-1. The odd frame voltage ................................................................................................... 614
Table 23-2. The even frame voltage ................................................................................................. 615
Table 23-3. The all common signal driver ....................................................................................... 615
Table 24-1. Operating mode and calibration .................................................................................. 626
Table 26-1. Revision history ............................................................................................................... 666
GD32F1x0 User Manual
1
1. System and memory architecture
The system architecture of the devices of GD32F1x0 series that includes the ARM® Cortex™-
M3 processor, bus architecture and memory organization will be described in the following
sections. The Cortex™-M3 processor is a next generation processor core which offers many
new features. Integrated and advanced features make the Cortex™-M3 processor suitable
for market products that require microcontrollers with high performance and low power
consumption. In brief, the Cortex™-M3 processor includes three AHB buses known as I-Code,
D-Code and System buses. All memory accesses of the Cortex™-M3 processor are executed
on the three buses according to the different purposes and the target memory spaces. The
memory organization uses a Harvard architecture, pre-defined memory map and up to 4 GB
of memory space, making the system flexible and extendable.
1.1. ARM Cortex-M3 processor
The Cortex™-M3 processor is a general-purpose 32-bit processor core especially suitable for
products requiring high performance and low power consumption microcontrollers. It offers
many new features such as a Thumb-2 instruction sets, hardware divider, low latency of
interruption respond time, atomic bit-banding access and multiple buses for simultaneous
accesses. The Cortex™-M3 processor is based on the ARMv7 architecture and supports both
Thumb and Thumb-2 instruction sets. Some system peripherals listed below are also provided
by Cortex™-M3:
Internal Bus Matrix connected with I-Code bus, D-Code bus, System bus, Private
Peripheral Bus (PPB) and debug accesses (AHB-AP)
Nested Vectored Interrupt Controller (NVIC)
Flash Patch and Breakpoint (FPB)
Data Watchpoint and Trace (DWT)
Instrumentation Trace Macrocell (ITM)
Serial Wire JTAG Debug Port (SWJ-DP)
Trace Port Interface Unit (TPIU)
The following figure shows the Cortex™-M3 processor block diagram. For more information,
refer to the ARM® Cortex™-M3 Technical Reference Manual.
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Figure 1-1. Cortex™-M3 block diagram
1.2. System architecture
The system architecture of the GD32F1x0 series is shown in the following figure. The AHB
matrix based on AMBA 3.0 AHB-LITE is a multi-layer AHB, which enables parallel access
paths between multiple masters and slaves in the system. There are four masters on the AHB
matrix, including I-Code, D-Code, system bus of the Cortex™-M3 core and DMA. The I-Code
bus is the instruction bus and also used for vector fetches from the Code region (0x0000 0000
~ 0x1FFF FFFF) to the Cortex™-M3 core. The D-Code bus is used for loading/storing data
and also for debugging access of the Code region. Similarly, the System bus is used for
instruction/vector fetches, data loading/storing and debugging access of the system regions.
The System regions include the internal SRAM region and the Peripheral region. The AHB
matrix consists of five slaves, including I-Code and D-Code interfaces of the flash memory
controller, internal SRAM, AHB1 and AHB2.
The AHB2 connects with the GPIO ports. The AHB1 connects with the AHB peripherals
including two AHB-to-APB bridges which provide full synchronous connections between the
AHB1 and the two APB buses. The two APB buses connect with all the APB peripherals. Both
of the two APB buses are able to operate at full speed up to 72 MHz.
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Figure 1-2. Series system architecture of GD32F130xx and GD32F150xx devices
ICode DCode System
NVIC
TPIU SW
Flash
Memory
Controller
Flash
Memory
AHB Matrix
SRAM
Controller SRAM
AHB to APB
Bridge 2
GP DMA
7chs
USART0
SPI0/I2S0
ADC
TIMER16
12-bit
SAR ADC
IBus
ARM Cortex-M3
Processor
Fmax: 72MHz
POR/PDR
PLL
Fmax: 72MHz
LDO
1.2V
IRC8M
8MHz
HXTAL
4-32MHz
LVD
EXTI
Powered by VDD/VDDA
TIMER0
AHB1: Fmax = 72MHz
AHB to APB
Bridge 1
CRC RST/CLK
Controller
DBus
Touch
Sensing
Interface
AHB2: Fmax = 72MHz GPIO Ports
A, B, C, D, F
IRC14M
14MHz
CMP
SYS Config
TIMER14
TIMER15
APB2: Fmax = 72MHz
IRC40K
40KHz
Powered by LDO (1.2V)
CMP0
CMP1
TIMER5
WWDGT
APB1: Fmax = 72MHz
SPI1
USART1
I2C0
I2C1
USBD
RTC
FWDGT
USBD SRAM
PMU
DAC
HDMI-CEC
12-bit
DAC
TIMER13
TIMER2
TIMER1
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Figure 1-3. Series system architecture of GD32F170xx and GD32F190xx devices
ICode DCode System
NVIC
TPIU SW
Flash
Memory
Controller
Flash
Memory
AHB Matrix
SRAM
Controller SRAM
AHB to APB
Bridge 2
GP DMA 7chs
USART0
SPI0/I2S0
ADC
TIMER16
12-bit
SAR ADC
IBus
ARM Cortex-M3
Processor
Fmax: 72MHz
POR/PDR
PLL
Fmax: 72MHz
LDO
1.8V
IRC8M
8MHz
HXTAL
4-32MHz
LVD
EXTI
Powered by VDD/VDDA
TIMER0
AHB1: Fmax = 72MHz
AHB to APB
Bridge 1
CRC RST/CLK
Controller
DBus
Touch
Sensing
Interface
AHB2: Fmax = 72MHz GPIO Ports
A, B, C, D, F
IRC28M
28MHz
CMP
SYS Config
TIMER14
TIMER15
APB2: Fmax = 72MHz
IRC40K
40KHz
Powered by LDO (1.8V)
CMP0
CMP1
TIMER5
WWDGT
APB1: Fmax = 72MHz
SPI1
USART1
I2C0~2
CAN1
RTC
FWDGT
CAN SRAM
PMU
DAC0~1
HDMI-CEC
12-bit
DAC
TIMER13
TIMER2
TIMER1
CAN0
SLCD
OPA
IVREF
SPI2/I2S2
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1.3. Memory map
The ARM® Cortex™-M3 processor is structured in Harvard architecture which can use
separate buses to fetch instructions and load/store data. The instruction code and data are
both located in the same memory address space but in different address ranges. Program
memory, data memory, registers and I/O ports are organized within the same linear 4-Gbyte
address space which is the maximum address range of the Cortex™-M3 since it has a 32-bit
bus address width. Additionally, a pre-defined memory map is provided by the Cortex™-M3
processor to reduce the software complexity of repeated implementation of different device
vendors. However, some regions are used by the ARM® Cortex™-M3 system peripherals.
The following figure shows the memory map of the GD32F1x0 series of devices, including
Code, SRAM, peripheral, and other pre-defined regions. Each peripheral of either type is
allocated 1KB of space. This allows simplifying the address decoding for each peripheral. The
APB1 peripherals are located at the address region from 0x4000 0000 to 0x4000 FFFF, while
the APB2 peripherals are located from 0x4001 0000 to 0x4001 7FFF. The address region
from 0x4002 0000 to 0x4002 FFFF is used for AHB1 peripherals, and the address region from
0x4800 0000 to 0x4800 FFFF is used for AHB2 peripherals.
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Figure 1-4. Memory map of GD32F130xx and GD32F150xx devices
Cortex-M3 Internal
Peripherals
Peripherals
SRAM
0xFFFF FFFF
0xE010 0000
0xE000 0000
0xC000 0000
0xA000 0000
0x8000 0000
0x6000 0000
0x4000 0000
0x2000 0000
0x0000 0000
7
6
5
4
3
2
1
0
reserved
reserved
reserved
reserved
reserved
reserved
reserved
reserved
reserved
reserved
Aliased to Flash or
system memory
according to BOOT
pins configuration
System
memory
Option
Bytes
Flash
memory
0x1FFF FFFF
0x1FFF F80F
0x1FFF F800
0x1FFF EC00
0x0801 FFFF
0x0800 0000
0x0000 0000 TIMER1
0x4000 0000
TIMER2
0x4000 0400
0x4000 0800 reserved
0x4000 1000 TIMER5
0x4000 1400 reserved
0x4000 2000 TIMER13
0x4000 2400 reserved
0x4000 2800 RTC
0x4000 2C00 WWDGT
0x4000 3000 FWDGT
0x4000 3400 reserved
0x4000 3800 SPI1
0x4000 3C00 reserved
0x4000 4000 reserved
0x4000 4400 USART1
0x4000 4800 reserved
0x4000 5400 I2C0
0x4000 5800 I2C1
0x4000 5C00 USB registers
0x4000 6000 USB SRAM (512B)
0x4000 6400 reserved
0x4000 7000 PMU
0x4000 7400 DAC
0x4000 7800 CEC
0x4000 7C00 reserved
0x4000 C000 reserved
0x4000 C400 reserved
0x4001 0000 SYSCFG + CMP
0x4001 0400 EXTI
0x4001 0800 reserved
0x4001 2400 ADC
0x4001 2800 reserved
0x4001 2C00 TIMER0
0x4001 3000 SPI0/I2S0
0x4001 3400 reserved
0x4001 3800 USART0
0x4001 3C00 reserved
0x4001 4000 TIMER14
0x4001 4400 TIMER15
0x4001 4800 TIMER16
0x4001 4C00 reserved
0x4002 0000 DMA
0x4002 0400 reserved
0x4002 1000 RCU
0x4002 1400 reserved
0x4002 2000 FMC
0x4002 2400 reserved
0x4002 3000 CRC
0x4002 3400 reserved
0x4002 4000 TSI
0x4002 4400 reserved
0x4800 0000 Port A
0x4800 0400 Port B
0x4800 0800 Port C
0x4800 0C00 Port D
0x4800 1000 reserved
0x4800 1400 Port F
0x4800 1800 reserved
0x5000 0000
0x5000 0000
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Figure 1-5. Memory map of GD32F170xx and GD32F190xx devices
Cortex-M3 Internal
Peripherals
Peripherals
SRAM
0xFFFF FFFF
0xE010 0000
0xE000 0000
0xC000 0000
0xA000 0000
0x8000 0000
0x6000 0000
0x4000 0000
0x2000 0000
0x0000 0000
7
6
5
4
3
2
1
0
reserved
reserved
reserved
reserved
reserved
reserved
reserved
reserved
reserved
reserved
Aliased to Flash or
system memory
according to BOOT
pins configuration
System
memory
Option
Bytes
Flash
memory
0x1FFF FFFF
0x1FFF F80F
0x1FFF F800
0x1FFF EC00
0x0801 FFFF
0x0800 0000
0x0000 0000 TIMER1
0x4000 0000
TIMER2
0x4000 0400
0x4000 0800 reserved
0x4000 1000 TIMER5
0x4000 1400 reserved
0x4000 2000 TIMER13
0x4000 2400 SLCD
0x4000 2800 RTC
0x4000 2C00 WWDGT
0x4000 3000 FWDGT
0x4000 3400 reserved
0x4000 3800 SPI1
0x4000 3C00 SPI2/I2S2
0x4000 4000 reserved
0x4000 4400 USART1
0x4000 4800 reserved
0x4000 5400 I2C0
0x4000 5800 I2C1
0x4000 5C00
0x4000 6000 CAN SRAM (256B)
0x4000 6400
reserved
0x4000 7000 PMU
0x4000 7400 DAC0~1
0x4000 7800 CEC
0x4000 7C00
reserved
0x4000 C000 I2C2
0x4000 C400 reserved
0x4001 0000 SYSCFG + CMP
0x4001 0400 EXTI
0x4001 0800 reserved
0x4001 2400 ADC
0x4001 2800 reserved
0x4001 2C00 TIMER0
0x4001 3000 SPI0/I2S0
0x4001 3400 reserved
0x4001 3800 USART0
0x4001 3C00 reserved
0x4001 4000 TIMER14
0x4001 4400 TIMER15
0x4001 4800 TIMER16
0x4001 4C00 reserved
0x4002 0000 DMA
0x4002 0400 reserved
0x4002 1000 RCU
0x4002 1400 reserved
0x4002 2000 FMC
0x4002 2400 reserved
0x4002 3000 CRC
0x4002 3400 reserved
0x4002 4000 TSI
0x4002 4400 reserved
0x4800 0000 Port A
0x4800 0400 Port B
0x4800 0800 Port C
0x4800 0C00 Port D
0x4800 1000 reserved
0x4800 1400 Port F
0x4800 1800 reserved
0x5000 0000
0x5000 0000
reserved
CAN1
CAN0
0x4000 6800
0x4000 6C00
OPA+IVREF
0x4000 8000
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1.3.1. Bit-banding
In order to reduce the time of read-modify-write operations, the Cortex™-M3 processor
provides a bit-banding function to perform a single atomic bit operation. The memory map
includes two bit-band regions. These occupy the SRAM and Peripherals respectively. These
bit-band regions map each word in an alias region of memory to a bit in a bit-band region of
memory.
A mapping formula shows how to reference each word in the alias region to a corresponding
bit, or target bit, in the bit-band region. The mapping formula is:
bit_word_addr = bit_band_base + (byte_offset x 32) + (bit_number × 4)
where:
Bit_word_addr is the address of the word in the alias memory region that maps to the
targeted bit.
Bit_band_base is the starting address of the alias region.
Byte_offset is the number of the byte in the bit-band region that contains the targeted bit.
Bit_number is the bit position (0-7) of the targeted bit.
For example, to access bit 7 of address 0x2000 0200, the bit-band alias is:
bit_word_addr = 0x2200 0000 + (0x200 * 32) + (7 * 4) = 0x2200 401C
Writing to address 0x2200 401C will cause bit 7 of address 0x2000 0200 change while a read
to address 0x2200 401C will return 0x01 or 0x00 according to the value of bit 7 at the SRAM
address 0x2000 0200.
1.3.2. On-chip SRAM memory
The devices of GD32F1x0 series contain up to 8 KB of on-chip SRAM which starts at the
address 0x2000 0000. It supports byte, half-word (16 bits), and word (32 bits) accesses. In
order to increase memory robustness, parity check is supported. The user can enable the
parity check function using the bit OB_SRAM_PARITY_CHECK in the user option byte (refer
to Chapter 3.3.9 Option bytes). When enabled, an NMI is generated if the parity check fails.
The SRAM parity check error flag is implemented in the system configuration register 2
(SYSCFG_CFG2). The error flag can be connected to the break input of TIMER 0/ TIMER
14/ TIMER 15/ TIMER 16, if the SRAM_PARITY_ERROR_LOCK control bit in the the system
configuration register 2 (SYSCFG_CFG2) is set to 1.
The real data width of the SRAM is 36 bits, including 32 bits for data and 4 bits for parity (1
bit per byte). When writing, the parity bits are computed and stored into the SRAM. When
reading, the parity bits are also computed using the stored data in SRAM. The computed
parity bits are compared with the stored parity bits which are computed during the writing
access. If they are different, the parity check fails.
Note: When enabling the SRAM parity check, it is recommended to initialize the whole SRAM
memory by software at the beginning of the code, in order to avoid getting parity check errors
GD32F1x0 User Manual
9
when reading non-initialized locations.
1.3.3. On-chip Flash memory
For GD32F130xx and GD32F150xx devices
The devices provide up to 64 KB of on-chip flash memory. The flash memory consists of up
to 64 KB main flash organized into 64 pages with 1 KB capacity per page and a 3 KB
information block for the boot loader. The following table shows details.
Table 1-1. Flash module organization
Block
Name
Address
Main Flash Block
Page 0
0x0800 0000 - 0x0800 03FF
Page 1
0x0800 0400 - 0x0800 07FF
Page 2
0x0800 0800 - 0x0800 0BFF
·
·
·
·
Page 63
0x0800 FC00 - 0x0800
FFFF
Information Block
System memory
0x1FFF EC00 - 0x1FFF
F7FF
Option Bytes
0x1FFF F800 - 0x1FFF
F80F
Read accesses to the preceding 32 pages can be performed 32 bits per cycle without any
wait state. All of byte, half-word (16 bits) and word (32 bits) read accesses are supported.
The flash memory can be programmed half-word (16 bits) or word (32 bits) at a time. Each
page of the flash memory can be erased individually. The whole flash memory space except
information blocks can be erased at a time.
For GD32F170xx and GD32F190xx devices
The devices provide up to 128 KB of on-chip flash memory. The flash memory consists of up
to 128 KB main flash organized into 128 pages with 1 KB capacity per page and a 3 KB
information block for the boot loader. The following table shows details.
Table 1-2. Flash module organization
Block
Name
Address
Main Flash Block
Page 0
0x0800 0000 - 0x0800 03FF
Page 1
0x0800 0400 - 0x0800 07FF
Page 2
0x0800 0800 - 0x0800 0BFF
·
·
·
·
Page 127
0x0801 FC00 - 0x0801
FFFF
Information Block
System memory
0x1FFF EC00 - 0x1FFF
GD32F1x0 User Manual
10
F7FF
Option Bytes
0x1FFF F800 - 0x1FFF
F80F
Read accesses to the preceding 32 pages can be performed 32 bits per cycle without any
wait state. All of byte, half-word (16 bits) and word (32 bits) read accesses are supported.
The flash memory can be programmed half-word (16 bits) or word (32 bits) at a time. Each
page of the flash memory can be erased individually. The whole flash memory space except
information blocks can be erased at a time.
1.4. Boot configuration
The devices of GD32F1x0 series provides three kinds of boot sources which can be selected
using the bit OB_BOOT1_n in the user option byte (refer to Chapter 3.3.9 Option bytes) and
the BOOT0 pins. The value on the BOOT0 pin is latched on the 4th rising edge of SYSCLK
after a reset. It is up to the user to set the OB_BOOT1_n and BOOT0 after a power-on reset
or a system reset to select the required boot source. The details are shown in the following
table.
Table 1-3. Boot modes
Selected boot source
Boot mode selection pins
Boot1
Boot0
Main Flash Memory
x
0
System Memory
0
1
On-chip SRAM
1
1
1. The BOOT1 value is the opposite of the OB_BOOT1_n value.
After power-on sequence or a system reset, the ARM® Cortex™-M3 processor fetches the
top-of-stack value from address 0x0000 0000 and the base address of boot code from 0x0000
0004 in sequence. Then, it starts executing code from the base address of boot code.
According to the selected boot source, either the main flash memory (original memory space
beginning at 0x0800 0000) or the system memory (original memory space beginning at
0x1FFF EC00) is aliased in the boot memory space which begins at the address 0x0000 0000.
When the on-chip SRAM whose memory space is beginning at 0x2000 0000 is selected as
the boot source, in the application initialization code, you have to relocate the vector table in
SRAM using the NVIC exception table and offset register.
The embedded boot loader is located in the System memory, which is used to reprogram the
Flash memory. In GD32F1x0 devices, the boot loader can be activated through one of the
following serial interfaces: USART0 or USART1.
GD32F1x0 User Manual
11
1.5. System configuration registers (SYSCFG)
1.5.1. System configuration register 0 (SYSCFG_CFG0)
Address offset: 0x00
Reset value: 0x0000 000X (X indicates BOOT_MODE[1:0] may be any value according to
the BOOT0 pin and the OB_BOOT1_n option bit after reset)
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
PB9_HCCE
Reserved
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
TIMER16_
DMA_RMP
TIMER15_
DMA_RMP
USART0
_RX_
DMA_RMP
USART0
_TX_
DMA_RMP
ADC_
DMA_RMP
Reserved
BOOT_MODE[1:0]
rw
rw
rw
rw
rw
r
Bits
Fields
Descriptions
31:20
Reserved
Must be kept at reset value
19
PB9_HCCE
PB9 pin high current capability enable
When it is set, the PB9 pin can be used to control an infrared LED directly.
0: High current capability on the PB9 pin is disabled.
1: High current capability on the PB9 pin is enabled, and the speed control of
the pin is bypassed.
18:13
Reserved
Must be kept at reset value
12
TIMER16_DMA_RMP
Timer 16 DMA request remapping enable
0: Not remap (TIMER16_CH0 and TIMER16_UP DMA requests are mapped
on DMA channel 0)
1: Remap (TIMER16_CH0 and TIMER16_UP DMA requests are mapped on
DMA channel 1)
11
TIMER15_DMA_RMP
Timer 15 DMA request remapping enable
0: Not remap (TIMER15_CH0 and TIMER15_UP DMA requests are mapped
on DMA channel 2)
1: Remap (TIMER15_CH0 and TIMER15_UP DMA requests are mapped on
DMA channel 3)
10
USART0_RX_DMA_RMP
USART0_RX DMA request remapping enable
0: Not remap (USART0_RX DMA requests are mapped on DMA channel 2)
1: Remap (USART0_RX DMA requests are mapped on DMA channel 4)
9
USART0_TX_DMA_RMP
USART0_TX DMA request remapping enable
GD32F1x0 User Manual
12
0: Not remap (USART0_TX DMA requests are mapped on DMA channel 1)
1: Remap (USART0_TX DMA requests are mapped on DMA channel 3)
8
ADC_DMA_RMP
ADC DMA request remapping enable
0: Not remap (ADC DMA requests are mapped on DMA channel 0)
1: Remap (ADC DMA requests are mapped on DMA channel 1)
7:2
Reserved
Must be kept at reset value
1:0
BOOT_MODE
[1:0]
Boot mode (Refer to Chapter 1.4 Boot configuration for details)
Bit0 is mapping to the BOOT0 pin; the value of bit1 is the opposite of the
OB_BOOT1_n option bit value.
x0: Boot from the Main Flash
01: Boot from the system memory
11: Boot from the embedded SRAM
1.5.2. System configuration register 1 (SYSCFG_CFG1)
Address offset: 0x04
Reset value: 0x0000 0000
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
SLCD_DECA
Reserved
rw
Bits
Fields
Descriptions
31:4
Reserved
Must be kept at reset value
3:1
SLCD_DECA
Decoupling capacitance connection for SLCD
Bit1: Decoupling capacitance connection to PB2 or not
Bit2: Decoupling capacitance connection to PB12 or not
Bit3: Decoupling capacitance connection to PB0 or not
0
Reserved
Must be kept at reset value
1.5.3. EXTI sources selection register 0 (SYSCFG_EXTISS0)
Address offset: 0x08
Reset value: 0x0000 0000
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
GD32F1x0 User Manual
13
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
EXTI3_SS [3:0]
EXTI2_SS [3:0]
EXTI1_SS [3:0]
EXTI0_SS [3:0]
rw
rw
rw
rw
Bits
Fields
Descriptions
31:16
Reserved
Must be kept at reset value
15:12
EXTI3_SS[3:0]
EXTI 3 sources selection
X000: PA3 pin
X001: PB3 pin
X010: PC3 pin
X011: Reserved
X100: Reserved
X101: Reserved
X110: Reserved
X111: Reserved
11:8
EXTI2_SS[3:0]
EXTI 2 sources selection
X000: PA2 pin
X001: PB2 pin
X010: PC2 pin
X011: PD2 pin
X100: Reserved
X101: Reserved
X110: Reserved
X111: Reserved
7:4
EXTI1_SS[3:0]
EXTI 1 sources selection
X000: PA1 pin
X001: PB1 pin
X010: PC1 pin
X011: Reserved
X100: Reserved
X101: PF1 pin
X110: Reserved
X111: Reserved
3:0
EXTI0_SS[3:0]
EXTI 0 sources selection
X000: PA0 pin
X001: PB0 pin
X010: PC0 pin
X011: Reserved
X100: Reserved
GD32F1x0 User Manual
14
X101: PF0 pin
X110: Reserved
X111: Reserved
1.5.4. EXTI sources selection register 1 (SYSCFG_EXTISS1)
Address offset: 0x0C
Reset value: 0x0000 0000
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
EXTI7_SS [3:0]
EXTI6_SS [3:0]
EXTI5_SS [3:0]
EXTI4_SS [3:0]
rw
rw
rw
rw
Bits
Fields
Descriptions
31:16
Reserved
Must be kept at reset value
15:12
EXTI7_SS[3:0]
EXTI 7 sources selection
X000: PA7 pin
X001: PB7 pin
X010: PC7 pin
X011: Reserved
X100: Reserved
X101: PF7 pin
X110: Reserved
X111: Reserved
11:8
EXTI6_SS[3:0]
EXTI 6 sources selection
X000: PA6 pin
X001: PB6 pin
X010: PC6 pin
X011: Reserved
X100: Reserved
X101: PF6 pin
X110: Reserved
X111: Reserved
7:4
EXTI5_SS[3:0]
EXTI 5 sources selection
X000: PA5 pin
X001: PB5 pin
X010: PC5 pin
X011: Reserved
GD32F1x0 User Manual
15
X100: Reserved
X101: PF5 pin
X110: Reserved
X111: Reserved
3:0
EXTI4_SS[3:0]
EXTI 4 sources selection
X000: PA4 pin
X001: PB4 pin
X010: PC4 pin
X011: Reserved
X100: Reserved
X101: PF4 pin
X110: Reserved
X111: Reserved
1.5.5. EXTI sources selection register 2 (SYSCFG_EXTISS2)
Address offset: 0x10
Reset value: 0x0000 0000
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
EXTI11_SS [3:0]
EXTI10_SS [3:0]
EXTI9_SS [3:0]
EXTI8_SS [3:0]
rw
rw
rw
rw
Bits
Fields
Descriptions
31:16
Reserved
Must be kept at reset value
15:12
EXTI11_SS[3:0]
EXTI 11 sources selection
X000: PA11 pin
X001: PB11 pin
X010: PC11 pin
X011: Reserved
X100: Reserved
X101: Reserved
X110: Reserved
X111: Reserved
11:8
EXTI10_SS[3:0]
EXTI 10 sources selection
X000: PA10 pin
X001: PB10 pin
X010: PC10 pin
GD32F1x0 User Manual
16
X011: Reserved
X100: Reserved
X101: Reserved
X110: Reserved
X111: Reserved
7:4
EXTI9_SS[3:0]
EXTI 9 sources selection
X000: PA9 pin
X001: PB9 pin
X010: PC9 pin
X011: Reserved
X100: Reserved
X101: Reserved
X110: Reserved
X111: Reserved
3:0
EXTI8_SS[3:0]
EXTI 8 sources selection
X000: PA8 pin
X001: PB8 pin
X010: PC8 pin
X011: Reserved
X100: Reserved
X101: Reserved
X110: Reserved
X111: Reserved
1.5.6. EXTI sources selection register 3 (SYSCFG_EXTISS3)
Address offset: 0x14
Reset value: 0x0000 0000
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
EXTI15_SS [3:0]
EXTI14_SS [3:0]
EXTI13_SS [3:0]
EXTI12_SS [3:0]
rw
rw
rw
rw
Bits
Fields
Descriptions
31:16
Reserved
Must be kept at reset value
15:12
EXTI15_SS[3:0]
EXTI 15 sources selection
X000: PA15 pin
X001: PB15 pin
GD32F1x0 User Manual
17
X010: PC15 pin
X011: Reserved
X100: Reserved
X101: Reserved
X110: Reserved
X111: Reserved
11:8
EXTI14_SS[3:0]
EXTI 14 sources selection
X000: PA14 pin
X001: PB14 pin
X010: PC14 pin
X011: Reserved
X100: Reserved
X101: Reserved
X110: Reserved
X111: Reserved
7:4
EXTI13_SS[3:0]
EXTI 13 sources selection
X000: PA13 pin
X001: PB13 pin
X010: PC13 pin
X011: Reserved
X100: Reserved
X101: Reserved
X110: Reserved
X111: Reserved
3:0
EXTI12_SS[3:0]
EXTI 12 sources selection
X000: PA12 pin
X001: PB12 pin
X010: PC12 pin
X011: Reserved
X100: Reserved
X101: Reserved
X110: Reserved
X111: Reserved
1.5.7. System configuration register 2 (SYSCFG_CFG2)
Address offset: 0x18
Reset value: 0x0000 0000
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
GD32F1x0 User Manual
18
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
SRAM_PCEF
Reserved
LVD_
LOCK
SRAM_
PARITY_
ERROR_
LOCK
LOCK
UP_
LOCK
rw
rw
rw
rw
Bits
Fields
Descriptions
31:9
Reserved
Must be kept at reset value
8
SRAM_PCEF
SRAM parity check error flag
This bit is set by hardware when an SRAM parity check error occurs. It is
cleared by software by writing 1.
0: No SRAM parity check error detected
1: SRAM parity check error detected
7:3
Reserved
Must be kept at reset value
2
LVD_LOCK
LVD lock
This bit is set by software and cleared by a system reset.
0: The LVD interrupt is disconnected from the break input of TIMER0/14/15/16.
LVDEN and LVDT[2:0] in the PMU_CTL register can be programmed.
1: The LVD interrupt is connected from the break input of TIMER0/14/15/16.
LVDEN and LVDT[2:0] in the PMU_CTL register are read only.
1
SRAM_PARITY_
ERROR_LOCK
SRAM parity check error lock
This bit is set by software and cleared by a system reset.
0: The SRAM parity check error is disconnected from the break input of
TIMER0/14/15/16
1: The SRAM parity check error is connected from the break input of
TIMER0/14/15/16
0
LOCKUP_LOCK
Cortex-M3 LOCKUP output lock
This bit is set by software and cleared by a system reset.
0: The Cortex-M3 LOCKUP output is disconnected from the break input of
TIMER0/14/15/16
1: The Cortex-M3 LOCKUP output is connected from the break input of
TIMER0/14/15/16
1.6. Device electronic signature
The device electronic signature contains memory density information and the 96-bit unique
device ID. It is stored in the information block of the Flash memory. The 96-bit unique device
ID is unique for any device. It can be used as serial numbers, or part of security keys, etc.
GD32F1x0 User Manual
19
1.6.1. Memory density information
Base address: 0x1FFF F7E0
The value is factory programmed and can never be altered by user.
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
SRAM_DENSITY[15:0]
r
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
FLASH_DENSITY[15:0]
r
Bits
Fields
Descriptions
31:16
SRAM_DENSITY
[15:0]
SRAM density
The value indicates the on-chip SRAM density of the device in Kbytes.
Example: 0x0008 indicates 8 Kbytes.
15:0
FLASH_DENSITY
[15:0]
Flash memory density
The value indicates the Flash memory density of the device in Kbytes.
Example: 0x0020 indicates 32 Kbytes.
1.6.2. Unique device ID (96 bits)
Base address: 0x1FFF F7AC
The value is factory programmed and can never be altered by user.
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
UNIQUE_ID[31:16]
r
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
UNIQUE_ID[15:0]
r
Bits
Fields
Descriptions
31:0
UNIQUE_ID[31:0]
Unique device ID
Base address: 0x1FFF F7B0
The value is factory programmed and can never be altered by user.
This register has to be accessed by word(32-bit)
GD32F1x0 User Manual
20
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
UNIQUE_ID[63:48]
r
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
UNIQUE_ID[47:32]
r
Bits
Fields
Descriptions
31:0
UNIQUE_ID[63:32]
Unique device ID
Base address: 0x1FFF F7B4
The value is factory programmed and can never be altered by user.
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
UNIQUE_ID[95:80]
r
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
UNIQUE_ID[79:64]
r
Bits
Fields
Descriptions
31:0
UNIQUE_ID[95:64]
Unique device ID
GD32F1x0 User Manual
21
2. Power management unit (PMU)
2.1. Introduction
The power consumption is regarded as one of the most important issues for the devices of
GD32F1x0 series. Accordingly the Power management unit (PMU), provide three types of
power saving modes, including Sleep, Deep-sleep and Standby mode. These modes reduce
the power consumption and allow the application to achieve the best tradeoff among the
conflicting demands of CPU operating time, speed and power consumption. For GD32F130xx
and GD32F150xx devices, there are three power domains, including VDD domain, 1.2V
domain, and Backup domain, as is shown in the following figure. For GD32F170xx and
GD32F190xx devices, there are three power domains, including VDD domain, 1.8V domain,
and Backup domain, as is shown in the following figure. The power of the VDD domain is
supplied directly by VDD. An embedded LDO in the VDD domain is used to supply the 1.2V/1.8V
domain power. A power switch is implemented for the Backup domain. It can be powered
from the VBAT voltage when the main VDD supply is shut down.
2.2. Main features
Three power domains: VBAT, VDD and 1.2V power domains for GD32F130xx and
GD32F150xx devices or 1.8V power domains for GD32F170xx and GD32F190xx
devices
Three power saving modes: Sleep, Deep-sleep and Standby modes
Internal Voltage regulator supplies 1.2V voltage source for GD32F130xx and
GD32F150xx devices or 1.8 V voltage source for GD32F170xx and GD32F190xx
devices
20 bytes of backup register powered by VBAK for data protection of user application data
when in the Standby mode
Low Voltage Detector can issue an interrupt or event when the power is lower than a
programmed threshold
Battery power (VBAT) for Backup domain when VDD is shut down
Calibration register for storing the RTC calibration value
2.3. Function description
Figure below provides details on the internal configuration of the PMU and the relevant power
domains.
GD32F1x0 User Manual
22
Figure 2-1. Power supply overview of GD32F130xx and GD32F150xx devices
PMU
CTRL
FWDGT
IRC40K
LDO
LXTAL
RTC BREG
WKUP3
IRC8M
HXTAL
PLL
POR/PDR
BPOR
ADC
Backup Domain
NRST
PA0
VDD Domain
WKUP0
WKUP1
WKUP4
VDD
VBAT
Power Switch
3.3V
VBAK
Cortex-M3
AHB IPs
APB INTF2 APB INTF1
1.2V Domain
APB IPs
SLEEPING
SLEEPDEEP
1.2V
LVD
LVD: Low Voltage Detector LDO: Voltage Regulator BREG: Backup Registers
POR: Power On Reset PDR: Power Down Reset BPOR: VBAK Power On Reset
PC13
WKUP2
IRC14M DAC CMP
VDDA 3.3V
VDDA Domain
GD32F1x0 User Manual
23
Figure 2-2. Power supply overview of GD32F170xx and GD32F190xx devices
PMU
CTRL
FWDGT
IRC40K
LDO
LXTAL
RTC BREG
WKUP3
IRC8M
HXTAL
PLL
POR/PDR
BPOR
ADC
Backup Domain
NRST
PA0
VDD Domain
WKUP0
WKUP1
WKUP4
VDD
VBAT
Power Switch
5V
VBAK
Cortex-M3
AHB IPs
APB INTF2 APB INTF1
1.8V Domain
APB IPs
SLEEPING
SLEEPDEEP
1.8V
LVD
LVD: Low Voltage Detector LDO: Voltage Regulator BREG: Backup Registers
POR: Power On Reset PDR: Power Down Reset BPOR: VBAK Power On Reset
PC13
WKUP2
IRC28M DAC CMP
VDDA 5V
VDDA Domain
2.3.1. Battery backup domain
The Backup Domain contains BPOR (Backup Domain Power on Reset), BREG (Backup
Registers), RTC (Real Time Clock), LXTAL (Low Speed Crystal Oscillator), and three pads,
including PC13, PC14, and PC15. It is powered by the VDD or the battery power source (VBAT)
selected by the internal power switch. To retain the content of the Backup registers and supply
the RTC function, when VDD is turned off, VBAT pin can be connected to an optional standby
voltage supplied by a battery or by another source. The switch is controlled by the Power
Down Reset circuit in the VDD domain. If no external battery is used in the application, it is
recommended to connect VBAT externally to VDD with a 100nF external ceramic decoupling
capacitor.
The Backup Domain reset sources include BPOR and the Backup Domain software reset.
The BPOR signal forces the device to stay in the reset mode until VBAK is completely powered
up. Also the application software can trigger the Backup domain software reset by setting the
BKPRST bit in the RCU_BDCTL register to reset the Backup domain.
The clock source of RTC circuit can be derived from the Internal 40KHz RC oscillator
(IRC40K), the Low Speed Crystal oscillator (LXTAL) or HXTAL clock divided by 32. When
VDD is shut down, only LXTAL is valid for RTC. Before entering the power saving mode by
GD32F1x0 User Manual
24
executing the WFI/WFE instruction, the Cortex™-M3 needs to setup the RTC register with an
expected wakeup time and enable the wakeup function to achieve the RTC timer wakeup
event. After entering the power saving mode for a certain amount of time, the RTC alarm will
be asserted to wake up the device when the time match event occurs. The details of the RTC
configuration and operation will be described in the RTC chapter.
Five 32-bit registers, up to 20 bytes, are provided located in the Backup Domain for user
application data storage. These registers are powered by VBAK which constantly supplies
power when the VDD power is switched off. The Backup Registers are only reset by the Backup
Domain power-on-reset or the Backup Domain software reset.
When the Backup domain is supplied by VDD (VBAK pin is connected to VDD), the following
functions are available:
PC13 can be used as GPIO, TAMPER pin, RTC Calibration, RTC Alarm or second output.
(refer to Chapter 20: Real-time Clock (RTC))
PC14 and PC15 can be used as either GPIO or LXTAL Crystal oscillator pins.
When the Backup domain is supplied by VBAT (VBAK pin is connected to VBAT), the following
functions are available:
PC13 can be used as TAMPER pin, RTC Alarm or second output. (refer to Chapter 20:
Real-time Clock (RTC))
PC14 and PC15 can be used as LXTAL Crystal oscillator pins only.
Note: Since PC13, PC14 and PC15 are supplied through the Power Switch, which can only
be obtained by a small current, the speed of GPIOs PC13 to PC15 should not exceed 2MHz
when they are in output mode.
2.3.2. VDD/VDDA power domain
Most of analog modules are located in the VDDA domain, including IRC8M (Internal 8MHz RC
oscillator), IRC14M (Internal 14MHz RC oscillator) for GD32F130xx and GD32F150xx
devices or IRC28M (Internal 28MHz RC oscillator) for GD32F170xx and GD32F190xx
devices, IRC40K (Internal 40KHz RC oscillator), PLL (Phase Locking Loop), ADC (Analog to
Digital Converter), DAC (Digital to Analog Converter), LVD (Low Voltage Detector), and
Comparator. Besides, LDO (Voltage Regulator), POR/PDR (Power On/Down Reset), HXTAL
(High Speed Crystal oscillator), FWDGT (Free Watchdog Timer), the power control logic, and
pads (except PC13, PC14, and PC15) are implemented in the VDD domain. The LDO is
implemented to supply power for the 1.2V domain in GD32F130xx and GD32F150xx devices
or 1.8V domain in GD32F170xx and GD32F190xx devices. Generally, digital circuits are
powered by VDD, while most of analog circuits are powered by VDDA. The independent power
supply VDDA is implemented to achieve better performance of analog circuits, especially to
improve the ADC and the DAC conversion accuracy. The voltage of VDDA can be equal or
higher than that of VDD. VDDA can be externally connected to VDD through the external filtering
circuit that avoids noise on VDDA. Or, if VDDA is different from VDD, VDDA must always be higher.
In this case, an external Shottky diode may be implemented between VDD and VDDA for safety.
GD32F1x0 User Manual
25
The LVD is used to detect whether the VDD or VDDA supply voltage is lower than the low voltage
detector threshold. The function is configured by the Control Register (PMU_CTL). The
LVDEN bit controls whether LVD is enabled or not, while the LVDT[2:0] bits select the low
voltage detector threshold from 2.2V to 2.9V for GD32F130xx and GD32F150xx devices or
2.4V to 4.5V for GD32F170xx and GD32F190xx devices. The low power detector status flag
(LVDF) is located in the Power Control/Status Register (PMU_CS). Besides, the low voltage
detected event is also connected to the EXTI line 16. Users can generate a corresponding
interrupt through configuring the EXTI line 16.
The POR/PDR circuit is implemented to detect VDD/VDDA and generate the power reset signal
which resets the whole chip except the Backup domain when the supply voltage is lower than
the specified threshold. The following figure shows the relationship between the supply
voltage and the power reset signal. VPOR indicates the threshold of power on reset, while VPDR
means the threshold of power down reset. For GD32F130xx and GD32F150xx devices, VPDR
is configurable. There are two VPDR values which can be selected by the PDVSEL bit in the
RCU_PDVSEL registers (Refer to Chapter4 RCU registers). When the lower one is selected,
it is strongly recommended that neither programming nor erasing is performed to the flash
memory since it may fail when the voltage is low enough nearly the threshold.
Figure 2-3. Waveform of the power reset
VDD/VDDA
VPOR
tRSTTEMPO
2ms
Power Reset (Active Low)
t
VPDR
Vhyst
50mv
GD32F1x0 User Manual
26
Figure 2-4. Waveform of LVD threshold
VDD/VDDA
LVD output
t
LVD threshold 100mV
Vhyst
2.3.3. 1.2V power domain for GD32F130xx and GD32F150xx devices
The main functions that include Cortex™-M3 logic, AHB/APB peripherals, the APB interfaces
for the Backup domain and the VDD domain, etc., are located in the 1.2V power domain. Once
the 1.2V is powered up, the POR will generate a reset sequence on the 1.2V power domain.
2.3.4. 1.8V power domain for GD32F170xx and GD32F190xx devices
The main functions that include Cortex™-M3 logic, AHB/APB peripherals, the APB interfaces
for the Backup domain and the VDD domain, etc., are located in the 1.8V power domain. Once
the 1.8V is powered up, the POR will generate a reset sequence on the 1.8V power domain.
2.3.5. Power saving modes
After a system reset or a power reset, the GD32F1x0 MCU operates at full function and all
power domains are active. Users can achieve lower power consumption through slowing
down the system clocks (HCLK, PCLK1, PCLK2) or gating the clocks of the unused
peripherals. Besides, three power saving modes are provided to achieve even lower power
consumption. They are Sleep mode, Deep-sleep mode, and Standby mode.
Sleep Mode
The Sleep mode is corresponding to the SLEEPING mode of the Cortex™-M3. In Sleep mode,
only clock of Cortex™-M3 is off. To enter the Sleep mode, it is only necessary to clear the
SLEEPDEEP bit in the Cortex™-M3 System Control Register, and execute a WFI or WFE
instruction. If the Sleep mode is entered by executing a WFI instruction, any interrupt can
wake up the system. If it is entered by executing a WFE instruction, any wakeup event can
GD32F1x0 User Manual
27
wake up the system. The mode offers the lowest wakeup time as no time is wasted in interrupt
entry or exit.
According to the SLEEPONEXIT bit in the Cortex™-M3 System Control Register, there are
two options to select the Sleep mode entry mechanism.
Sleep-now: if the SLEEPONEXIT bit is cleared, the MCU enters Sleep mode as soon as
WFI or WFE instruction is executed.
Sleep-on-exit: if the SLEEPONEXIT bit is set, the MCU enters Sleep mode as soon as it
exits from the lowest priority ISR.
Deep-sleep Mode
The Deep-sleep mode is based on the SLEEPDEEP mode of the Cortex™-M3. In Deep-sleep
mode, all clocks in the 1.2V domain for GD32F130/150xx devices or 1.8V domain for
GD32F170/190xx devices are off, and all of IRC8M, IRC14M for GD32F130/150xx devices
or IRC28M for GD32F170/190xx devices, HXTAL and PLL are disabled. The LDO can
operate normally or in low power mode depending on the LDOLP bit in the PMU_CTL register.
Before entering the Deep-sleep mode, it is necessary to set the SLEEPDEEP bit in the
Cortex™-M3 System Control Register, and clear the STBMOD bit in the PMU_CTL register.
Then, the device enters the Deep-sleep mode after a WFI or WFE instruction is executed.
Any interrupt or wakeup event from EXTI lines can wake up the system from the Deep-sleep
mode. When exiting the Deep-sleep mode, the IRC8M is selected as the system clock. Notice
that an additional wakeup delay will be incurred if the LDO operates in low power mode.
Note: In order to enter Deep-sleep mode smoothly, all EXTI line pending status (in the
EXTI_PD register) and RTC Alarm must be reset. If not, the program will skip the entry
process of Deep-sleep mode to continue to executive the following procedure.
Standby Mode
The Standby mode is based on the SLEEPDEEP mode of the Cortex™-M3, too. In Standby
mode, the whole 1.2V domain for GD32F130/150xx devices or 1.8V domain for
GD32F170/190xx devices is power off, the LDO is shut down, and all of IRC8M, IRC14M for
GD32F130/150xx devices or IRC28M for GD32F170/190xx devices, HXTAL and PLL are
disabled. Before entering the Standby mode, it is necessary to set the SLEEPDEEP bit in the
Cortex™-M3 System Control Register, and set the STBMOD bit in the PMU_CTL register,
and clear the WUF bit in the PMU_CS register. Then, the device enters the Standby mode
after a WFI or WFE instruction is executed. There are five wakeup sources for the Standby
mode, including the external reset from NRST pin, the RTC alarm, the FWDGT reset, and the
rising edge on WKUP0 or WKUP1 pin. The Standby mode achieves the lowest power
consumption, but spends longest time to wake up. Besides, the contents of SRAM and
registers (except Backup Registers) are lost in Standby mode. When exiting from the Standby
mode, a power-on reset occurs and the Cortex™-M3 will execute instruction code from the
0x0000 0000 address.
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Table 2-1. Power saving mode summary
Mode
Sleep
Deep-sleep
Standby
Description
Only CPU clock
is off
1. All clocks in the 1.2V
domain for
GD32F130/150xx
devices or 1.8V domain
for GD32F170/190xx
devices are off
2. Disable IRC8M, IRC14M
for GD32F130/150xx
devices or IRC28M for
GD32F170/190xx
devices, HXTAL and
PLL
1. 1.2V domain for
GD32F130/150xx
devices or 1.8V
domain for
GD32F170/190xx
devices is power off
2. Disable IRC8M,
IRC14M for
GD32F130/150xx
devices or IRC28M
for GD32F170/190xx
devices, HXTAL and
PLL
LDO Status
On
On or in low power mode
Off
Configuration
SLEEPDEEP = 0
SLEEPDEEP = 1
STBMOD = 0
SLEEPDEEP = 1
STBMOD = 1, WURST = 1
Entry
WFI or WFE
WFI or WFE
WFI or WFE
Wakeup
Any interrupt for
WFI
Any event for
WFE
Any interrupt or event from
EXTI lines
1. NRST pin
2. RTC alarm
3. FWDGT reset
4. WKUP0 pin
5. WKUP1 pin
Wakeup
Latency
None
IRC8M wakeup time
LDO wakeup time if LDO is in
low power mode
Power on sequence
2.4. PMU registers
2.4.1. Control register (PMU_CTL)
For GD32F130xx and GD32F150xx devices
Address offset: 0x00
Reset value: 0x0000 0000 (reset by wakeup from Standby mode)
This register can be accessed by half-word(16-bit) or word(32-bit).
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
BKPWEN
LVDT[2:0]
LVDEN
STBRST
WURST
STBMOD
LDOLP
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rw
rw
rw
rc_w1
rc_w1
rw
rw
Bits
Fields
Descriptions
31:9
Reserved
Must be kept at reset value
8
BKPWEN
Backup Domain Write Enable
0: Disable write access to the registers in Backup domain
1: Enable write access to the registers in Backup domain
After reset, any write access to the registers in Backup domain is ignored. This bit
has to be set to enable write access to these registers.
7:5
LVDT[2:0]
Low Voltage Detector Threshold
000: 2.2V
001: 2.3V
010: 2.4V
011: 2.5V
100: 2.6V
101: 2.7V
110: 2.8V
111: 2.9V
4
LVDEN
Low Voltage Detector Enable
0: Disable Low Voltage Detector
1: Enable Low Voltage Detector
Note: When LVD_LOCK bit is set to 1 in the SYSCFG_CFG2 register, LVDEN and
LVDT[2:0] are read only.
3
STBRST
Standby Flag Reset
0: No effect
1: Reset the standby flag
This bit is always read as 0.
2
WURST
Wakeup Flag Reset
0: No effect
1: Reset the wakeup flag
This bit is always read as 0.
1
STBMOD
Standby Mode
0: Enter the Deep-sleep mode when the Cortex™-M3 enters SLEEPDEEP mode
1: Enter the Standby mode when the Cortex™-M3 enters SLEEPDEEP mode
0
LDOLP
LDO Low Power Mode
0: The LDO operates normally during the Deep-sleep mode
1: The LDO is in low power mode during the Deep-sleep mode
Note: Some peripherals may work with the IRC8M clock in the Deep-sleep mode. In
this case, the LDO automatically switches from the low power mode to the normal
mode and remains in this mode until the peripheral stop working.
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30
For GD32F170xx and GD32F190xx devices
Address offset: 0x00
Reset value: 0x0000 0000 (reset by wakeup from Standby mode)
This register can be accessed by half-word(16-bit) or word(32-bit).
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
BKPWEN
LVDT[2:0]
LVDEN
STBRST
WURST
STBMOD
LDOLP
rw
rw
rw
rc_w1
rc_w1
rw
rw
Bits
Fields
Descriptions
31:9
Reserved
Must be kept at reset value
8
BKPWEN
Backup Domain Write Enable
0: Disable write access to the registers in Backup domain
1: Enable write access to the registers in Backup domain
After reset, any write access to the registers in Backup domain is ignored. This bit
has to be set to enable write access to these registers.
7:5
LVDT[2:0]
Low Voltage Detector Threshold
000: 2.4V
001: 2.7V
010: 3.0V
011: 3.3V
100: 3.6V
101: 3.9V
110: 4.2V
111: 4.5V
4
LVDEN
Low Voltage Detector Enable
0: Disable Low Voltage Detector
1: Enable Low Voltage Detector
Note: When LVD_LOCK bit is set to 1 in the SYSCFG_CFG2 register, LVDEN and
LVDT[2:0] are read only.
3
STBRST
Standby Flag Reset
0: No effect
1: Reset the standby flag
This bit is always read as 0.
2
WURST
Wakeup Flag Reset
0: No effect
1: Reset the wakeup flag
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31
This bit is always read as 0.
1
STBMOD
Standby Mode
0: Enter the Deep-sleep mode when the Cortex™-M3 enters SLEEPDEEP mode
1: Enter the Standby mode when the Cortex™-M3 enters SLEEPDEEP mode
0
LDOLP
LDO Low Power Mode
0: the LDO operates normally during the Deep-sleep mode
1: the LDO is in low power mode during the Deep-sleep mode
Note: Some peripherals may work with the IRC8M clock in the Deep-sleep mode. In
this case, the LDO automatically switches from the low power mode to the normal
mode and remains in this mode until the peripheral stop working.
2.4.2. Power control/status register (PMU_CS)
Address offset: 0x04
Reset value: 0x0000 0000 (not reset by wakeup from Standby mode)
This register can be accessed by half-word(16-bit) or word(32-bit).
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
WUPEN1
WUPEN0
Reserved
LVDF
STBF
WUF
rw
rw
r
r
r
Bits
Fields
Descriptions
31:10
Reserved
Must be kept at reset value
9
WUPEN1
WKUP1 Pin Enable
0: Disable WKUP1 pin function
1: Enable WKEP1 pin function
If WUPEN1 is set before entering the power saving mode, a rising edge on the
WKUP1 pin wakes up the system from the power saving mode. As the WKUP1 pin
is active high, this bit will setup an input pull down mode when the bit is high.
8
WUPEN0
WKUP0 Pin Enable
0: Disenable WKUP0 pin function
1: Enable WKUP0 pin function
If WUPEN0 is set before entering the power saving mode, a rising edge on the
WKUP0 pin wakes up the system from the power saving mode. As the WKUP0 pin
is active high, this bit will setup an input pull down mode when the bit is high.
7:3
Reserved
Must be kept at reset value
2
LVDF
Low Voltage Detector Status Flag
GD32F1x0 User Manual
32
0: Low Voltage event has not occurred (VDD is higher than the specified LVD
threshold)
1: Low Voltage event occurred (VDD is equal to or lower than the specified LVD
threshold)
Note: The LVD function is stopped in Standby mode.
1
STBF
Standby Flag
0: The device has not been in Standby mode
1: The device has been in Standby mode
This bit is cleared only by a POR/PDR or by setting the STBRST bit in the
PMU_CTL register.
0
WUF
Wakeup Flag
0: No wakeup event has been received
1: A wakeup event has been received from the WKUP pin or the RTC alarm
This bit is cleared only by a POR/PDR or by setting the WURST bit in the
PMU_CTL register.
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33
3. Flash memory controller (FMC)
3.1. Introduction
The Flash Memory Controller, FMC, provides all the necessary functions for the on-chip flash
memory. There is no waiting time within 32K bytes while CPU executes instruction. It also
provides page erase, mass erase, and word/half word program for flash memory.
3.2. Main features
For GD32F130xx and GD32F150xx devices：
Up to 64 KB of on-chip flash memory for storing instruction/data
No waiting time within 32K bytes when CPU executes instruction
A long delay when fetch 32K ~ 64K bytes date from flash
3K bytes information block for boot loader
16 bytes option bytes block for user application requirements
1K bytes page size
Word or half word programming, page erase and mass erase capability
Flash read protection to prevent illegal code/data access
Page erase/program protection to prevent unexpected operation
For GD32F170xx and GD32F190xx devices：
Up to 128 KB of on-chip flash memory for storing instruction/data
No waiting time within 32K bytes when CPU executes instruction
A long delay when fetch 32K ~ 128K bytes date from flash
3K bytes information block for boot loader
16 bytes option bytes block for user application requirements
1K bytes page size
Word or half word programming, page erase and mass erase capability
Flash read protection to prevent illegal code/data access
Page erase/program protection to prevent unexpected operation
3.3. Function description
3.3.1. Flash memory architecture
For GD32F130xx and GD32F150xx devices
The flash memory consists of up to 64 KB main flash organized into 64 pages with 1 KB
capacity per page and a 3 KB Information Block for the Boot Loader. The main flash memory
contains a total of up to 64 pages which can be erased individually. The following table shows
GD32F1x0 User Manual
34
the base address, size.
Table 3-1. Base address and size for flash memory
Block
Name
Address
size(bytes)
Main Flash Block
Page 0
0x0800 0000 - 0x0800 03FF
1KB
Page 1
0x0800 0400 - 0x0800 07FF
1KB
Page 2
0x0800 0800 - 0x0800 0BFF
1KB
.
.
.
.
.
.
.
.
.
Page 63
0x0800 FC00 - 0x0800 FFFF
1KB
Information Block
Boot Loader
0x1FFF EC00- 0x1FFF F7FF
3KB
Option byte Block
Option byte
0x1FFF F800 - 0x1FFF F80F
16B
Note: The Information Block stores the bootloader - this block cannot be programmed or
erased by user.
For GD32F170xx and GD32F190xx devices
The flash memory consists of up to 128 KB main flash organized into 128 pages with 1 KB
capacity per page and a 3 KB Information Block for the Boot Loader. The main flash memory
contains a total of up to 128 pages which can be erased individually. The following table
shows the base address, size.
Table 3-2 Base address and size for flash memory
Block
Name
Address
size(bytes)
Main Flash Block
Page 0
0x0800 0000 - 0x0800 03FF
1KB
Page 1
0x0800 0400 - 0x0800 07FF
1KB
Page 2
0x0800 0800 - 0x0800 0BFF
1KB
.
.
.
.
.
.
.
.
.
Page 127
0x0801 FC00 - 0x0801 FFFF
1KB
Information Block
Boot Loader
0x1FFF EC00- 0x1FFF F7FF
3KB
Option byte Block
Option byte
0x1FFF F800 - 0x1FFF F80F
16B
Note: The Information Block stores the bootloader - this block cannot be programmed or
erased by user.
3.3.2. Read operations
The flash can be addressed directly as a common memory space. Any instruction fetch and
the data access from the flash are through the IBUS or DBUS from the CPU.
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35
3.3.3. Unlock the FMC_CTL register
After reset, the FMC_CTL register is not accessible in write mode, except for the OBRLD bit,
which is used for reloading the option byte, and the LK bit in FMC_CTL register is 1. An
unlocking sequence consists of two write operations to the FMC_KEY register can open the
access to the FMC_CTL register. The two write operations are writing 0x45670123 and
0xCDEF89AB to the FMC_KEY register. After the two write operations, the LK bit in
FMC_CTL register is set to 0 by hardware. The software can lock the FMC_CTL again by
setting the LK bit in FMC_CTL register to 1. If there is any wrong operations on the FMC_KEY
register, the LK bit in FMC_CTL register will be set, and the FMC_CTL register will be locked,
then it will generate a bus error.
The OBPG bit and OBER bit in FMC_CTL are also protected by FMC_OBKEY register. The
unlocking sequence includes two write operations, which are writing 0x45670123 and
0xCDEF89AB to FMC_OBKEY register. And then set the OBWE bit in FMC_CTL register to
1. The software can set OBWE bit to 0 to protect the OBPG bit and OBER bit in FMC_CTL
register again.
3.3.4. Page erase
The FMC provides a page erase function which is used for initializing the contents of a Main
Flash memory page to a high state. Each page can be erased independently without affecting
the contents of other pages. The following steps show the access sequence of the register
for a page erase operation.
Unlock the FMC_CTL register if necessary.
Check the BUSY bit in FMC_STAT register to confirm that no Flash memory operation
is in progress (BUSY equal to 0). Otherwise, wait until the operation has been finished.
Write the page address into the FMC_ADDR register.
Write the page erase command into PER bit in FMC_CTL register.
Send the page erase command to the FMC by setting the START bit in FMC_CTL
register.
Wait until all the operations have been completed by checking the value of the BUSY bit
in FMC_STAT register.
Read and verify the page if required using a DBUS access.
When the operation is executed successfully, an interrupt will be triggered by FMC if the
ENDIE bit in the FMC_CTL register is set, and the END in FMC_STAT register is set. Note
that a correct target page address must be confirmed. The software may run out of control if
the target erase page is being used for fetching codes or accessing data. The FMC will not
provide any notification when this occurs. Additionally, the page erase operation will be
ignored on protected pages. A Flash Operation Error interrupt will be triggered by the FMC if
the ERRIE bit in the FMC_CTL register is set. The software can check the PGERR bit in the
FMC_STAT register to detect this condition in the interrupt handler. The end of this operation
is indicated by the END bit in the FMC_STAT register. The following figure shows the page
erase operation flow.
GD32F1x0 User Manual
36
Figure 3-1. Proccess of page erase operation
Set the FMC_ADDR,
PER bit
Is the LK bit 0
Send the command to
FMC by setting
START bit
Start
Yes
No Unlock the FMC_CTL
Is the BUSY bit 0
Yes
No
Is the BUSY bit 0
Yes
No
Finish
3.3.5. Mass erase
The FMC provides a complete erase function which is used for initializing the Main Flash
Block contents. The following steps show the mass erase register access sequence.
Unlock the FMC_CTL register if necessary.
Check the BUSY bit in FMC_STAT register to confirm that no Flash memory operation
is in progress (BUSY equal to 0). Otherwise, wait until the operation has been finished.
Write the mass erase command into MER bit in FMC_CTL register.
Send the mass erase command to the FMC by setting the START bit in FMC_CTL
register.
Wait until all the operations have been completed by checking the value of the BUSY bit
in FMC_STAT register.
Read and verify the Flash memory if required using a DBUS access.
When the operation is executed successfully, an interrupt will be triggered by FMC if the
ENDIE bit in the FMC_CTL register is set, and the END in FMC_STAT register is set. Since
GD32F1x0 User Manual
37
all flash data will be reset to a value of 0xFFFF_FFFF, the mass erase operation can be
implemented using a program that runs in SRAM or by using the debugging tool to access
the FMC registers directly. The end of this operation is indicated by the END bit in the
FMC_STAT register. (The starting address of programming operation should be 0x08000000)
The following figure indicates the mass erase operation flow.
Figure 3-2. Process of the mass erase operation
Set the MER bit
Is the LK bit 0
Send the command to
FMC by setting
START bit
Start
Yes
No Unlock the FMC_CTL
Is the BUSY bit 0
Yes
No
Is the BUSY bit 0
Yes
No
Finish
3.3.6. Main flash programming
The FMC provides a 32-bit word/16-bit half word programming function which is used to
modify the Main Flash memory contents. The following steps show the word programming
operation register access sequence.
Unlock the FMC_CTL register if necessary.
Check the BUSY bit in FMC_STAT register to confirm that no Flash memory operation
is in progress (BUSY equal to 0). Otherwise, wait until the operation has been finished.
Write the word program command into the PG bit in FMC_CTL register.
GD32F1x0 User Manual
38
A 32-bit word/16-bit half word write at desired address by DBUS.
Wait until all the operations have been completed by checking the value of the BUSY bit
in FMC_STAT register.
Read and verify the Flash memory if required using a DBUS access.
When the operation is executed successfully, an interrupt will be triggered by FMC if the
ENDIE bit in the FMC_CTL register is set, and the END in FMC_STAT register is set. Note
that before the word/half word programming operation you should check the address that it
has been erased. If the address has not been erased, PGERR bit will set when programming
the address except programming 0x0. Additionally, the program operation will be ignored on
protected pages. A Flash operation error interrupt will be triggered by the FMC if the ERRIE
bit in the FMC_CTL register is set. The software can check the PGERR bit in the FMC_STAT
register to detect this condition in the interrupt handler. The end of this operation is indicated
by the END bit in the FMC_STAT register. The following figure displays the word
programming operation flow.
Figure 3-3. Process of the word programming operation
Set the PG bit
Is the LK bit 0
Perform word/half
word write by DBUS
Start
Yes
No Unlock the FMC_CTL
Is the BUSY bit 0
Yes
No
Is the BUSY bit 0
Yes
No
Finish
3.3.7. Option byte erase
The FMC provides an erase function which is used for initializing the option byte block in flash.
The following steps show the erase sequence.
GD32F1x0 User Manual
39
Unlock the FMC_CTL register if necessary.
Unlock the OBWE bit in FMC_CTL register if necessary.
Check the BUSY bit in FMC_STAT register to confirm that no Flash memory operation
is in progress (BUSY equal to 0). Otherwise, wait until the operation has been finished.
Write the option byte erase command into OBER bit in FMC_CTL register.
Send the option byte erase command to the FMC by setting the START bit in FMC_CTL
register.
Wait until all the operations have been completed by checking the value of the BUSY bit
in FMC_STAT register.
Read and verify the Flash memory if required using a DBUS access.
When the operation is executed successfully, an interrupt will be triggered by FMC if the
ENDIE bit in the FMC_CTL register is set, and the END in FMC_STAT register is set. The
end of this operation is indicated by the END bit in the FMC_STAT register.
3.3.8. Option byte programming
The FMC provides a 32-bit word/16-bit half word programming function which is used for
modifying the option byte block contents. The following steps show the programming
operation sequence.
Unlock the FMC_CTL register if necessary.
Unlock the OBWE bit in FMC_CTL register if necessary.
Check the BUSY bit in FMC_STAT register to confirm that no Flash memory operation
is in progress (BUSY equal to 0). Otherwise, wait until the operation has been finished.
Write the program command into the OBPG bit in FMC_CTL register.
A 32-bit word/16-bit half word write at desired address by DBUS.
Wait until all the operations have been completed by checking the value of the BUSY bit
in FMC_STAT register.
Read and verify the Flash memory if required using a DBUS access.
When the operation is executed successfully, an interrupt will be triggered by FMC if the
ENDIE bit in the FMC_CTL register is set, and the END in FMC_STAT register is set. Note
that before the word/half word programming operation you should check the address that it
has been erased. If the address has not been erased, PGERR bit will set when programming
the address except programming 0x0. The end of this operation is indicated by the END bit
in the FMC_STAT register.
3.3.9. Option byte description
The option bytes block of flash memory reloaded to FMC_OBSTAT and FMC_WP registers
after each system reset or OBRLD bit set in FMC_CTL register, and the option bytes work.
The option complement bytes are the opposite of option bytes. When option bytes reload, if
the option complement bytes and option bytes does not match, the OBER bit in
FMC_OBSTAT register is set, and the option byte is set to 0xFF. The following table is the
detail of option bytes.
GD32F1x0 User Manual
40
Table 3-3. Option byte
Address
Name
Description
0x1fff f800
OB_SPC
option byte Security Protection Code
0xA5: No protection
any value except 0xA5 or 0xCC: Protection level low
0xCC: Protection level high
0x1fff f801
OB_SPC_N
OB_SPC complement value
0x1fff f802
OB_USER
option byte which user defined
[7]: Reserved
[6]: OB_SRAM_PARITY_CHECK
0: Enable sram parity check
1: Disable sram parity check
[5]: OB_VDDA_VISOR
0: Disable VDDA monitor
1: Enable VDDA monitor
[4]: OB_BOOT1_n
0: BOOT1 bit is 1
1: BOOT1 bit is 0
[3]: Reserved
[2]: OB_STDBY_RSTn
0: Generate a reset instead of entering standby mode
1: No reset when entering standby mode
[1]: OB_DSLP_RSTn
0: Generate a reset instead of entering Deep-sleep
mode
1: No reset when entering Deep-sleep mode
[0]: OB_WDG_SW
0: Hardware free watchdog timer
1: Software free watchdog timer
0x1fff f803
OB_USER_N
OB_USER complement value
0x1fff f804
OB_DATA[7:0]
user defined data bit 7 to 0
0x1fff f805
OB_DATA_N[7:0]
OB_DATA complement value bit 7 to 0
0x1fff f806
OB_DATA[15:8]
user defined data bit 15 to 8
0x1fff f807
OB_DATA_N[15:8]
OB_DATA complement value bit 15 to 8
0x1fff f808
OB_WP[7:0]
Page Erase/Program Protection bit 7 to 0
0x1fff f809
OB_WP_N[7:0]
OB_WP complement value bit 7 to 0
0x1fff f80a
OB_WP[15:8]
Page Erase/Program Protection bit 15 to 8
0x1fff f80b
OB_WP_N[15:8]
OB_WP complement value bit 15 to 8
3.3.10. Page erase/Program protection
The FMC provides page erase/program protection functions to prevent inadvertent operations
GD32F1x0 User Manual
41
on the Flash memory. The page erase or program will not be accepted by the FMC on
protected pages. If the page erase or program command is sent to the FMC on a protected
page, the WPERR bit in the FMC_STAT register will then be set by the FMC. If the WPERR
bit is set and the ERRIE bit is also set to 1 to enable the corresponding interrupt, then the
Flash operation error interrupt will be triggered by the FMC to get the attention of the CPU.
The page protection function can be individually enabled by configuring the OB_WP [15:0] bit
field to 0 in the option byte. If a page erase operation is executed on the Option Byte region,
all the Flash Memory page protection functions will be disabled. When setting or resetting
OB_WP in the option byte, the software need to set OBRLD in FMC_CTL register or a system
reset to reload the OB_WP bits. The following table shows which pages are protected by set
OB_WP [15:0].
Table 3-4. OB_WP bit for pages protected
OB_WP bit
pages protected
OB_WP[0]
page0 ~ page 3
OB_WP[1]
page4 ~ page 7
OB_WP[2]
page8 ~ page 11
.
.
.
.
.
.
OB_WP[14]
page56 ~ page59
OB_WP[15] for GD32F130xx
and GD32F150xx devices
page60 ~ page63
OB_WP[15] for GD32F170xx
and GD32F190xx devices
page60 ~ page127
3.3.11. Security protection
The FMC provides a security protection function to prevent illegal code/data access on the
Flash memory. This function is useful for protecting the software/firmware from illegal users.
There are 3 levels for protecting:
No protection: when setting OB_SPC byte and its complement value to 0xA55A, no protection
performed. The main flash and option bytes block are accessible by all operations.
Protection level low: when setting OB_SPC byte and its complement value to any value
except 0xA55A or 0xCC33, protection level low performed. The main flash can only be
accessed by user code. In debug mode, boot from SRAM or boot from boot loader mode, all
operations to main flash is forbidden. If a read operation is executed to main flash in debug
mode, boot from SRAM or boot from boot loader mode, a bus error will be generated. If a
program/erase operation is executed to main flash in debug mode, boot from SRAM or boot
from boot loader mode, the PGERR bit in FMC_STAT register will be set. At protection level
low, option bytes block are accessible by all operations. If program back to no protection level
by setting OB_SPC byte and its complement value to 0xA55A, a mass erase for main flash
will be performed.
GD32F1x0 User Manual
42
Protection level high: when set OB_SPC byte and its complement value to 0xCC33, protection
level high performed. When this level is programmed in debug mode, boot from SRAM or
boot from boot loader mode is disabled. All operations are from user code. The main flash
block is accessible by all operations. The option byte cannot be erased, and the OB_SPC
byte and its complement value cannot be reprogrammed. So, if protection level high is
programmed, it cannot move back to protection level low or no protection level.
3.4. FMC registers
3.4.1. Wait state register (FMC_WS)
Address offset: 0x00
Reset value: 0x0000 0000
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
WSCNT[2:0]
rw
Bits
Fields
Descriptions
31:3
Reserved
Must be kept at reset value
2:0
WSCNT[2:0]
Wait state counter register
These bits set and reset by software. The WSCNT valid when WSEN bit is
set
000: 0 wait state added
001: 1 wait state added
010: 2 wait state added
011 ~ 111: Reserved
3.4.2. Unlock key register (FMC_KEY)
Address offset: 0x04
Reset value: 0x0000 0000
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
KEY[31:16]
w
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
GD32F1x0 User Manual
43
KEY[15:0]
w
Bits
Fields
Descriptions
31:0
KEY[31:0]
FMC_CTL unlock registers
These bits are only be written by software
Write KEY[31:0] with key to unlock FMC_CTL register.
3.4.3. Option byte unlock key register (FMC_OBKEY)
Address offset: 0x08
Reset value: 0x0000 0000
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
OBKEY[31:16]
w
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
OBKEY[15:0]
w
Bits
Fields
Descriptions
31:0
OBKEY[31:0]
FMC_CTL option byte operation unlock registers
These bits are only be written by software
Write OBKEY[31:0] with key to unlock option byte command in FMC_CTL
register.
3.4.4. Status register (FMC_STAT)
Address offset: 0x0C
Reset value: 0x0000 0000
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
END
WPER
R
Reserved
.
PGER
R
Reserve
d
BUSY
rw
rw
rw
r
Bits
Fields
Descriptions
GD32F1x0 User Manual
44
31:6
Reserved
Must be kept at reset value
5
END
End of operation flag bit
When the operation executed successfully, this bit is set by hardware. The
software can clear it by writing 1.
4
WPERR
Erase/Program protection error flag bit
When erasing/programming on protected pages, this bit is set by hardware.
The software can clear it by writing 1.
3
Reserved
Must be kept at reset value
2
PGERR
Program error flag bit
When programming to the flash while it is not 0xFFFF, this bit is set by
hardware. The software can clear it by writing 1.
1
Reserved
Must be kept at reset value
0
BUSY
The flash busy bit
When the operation is in progress, this bit is set to 1. When the operation is
end or an error generated, this bit is clear to 0.
3.4.5. Control register (FMC_CTL)
Address offset: 0x10
Reset value: 0x0000 0080
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
OBR
LD
ENDI
E
Rese
rved
ERRI
E
OBW
E
Rese
rved
LK
STA
RT
OBE
R
OBP
G
Rese
rved
MER
PER
PG
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31:14
Reserved
Must be kept at reset value
13
OBRLD
Option byte reload bit
This bit is set by software.
0: No effect
1: Force option byte reload, and generate a system reset
12
ENDIE
End of operation interrupt enable bit
This bit is set or cleared by software.
0: No interrupt generated by hardware
GD32F1x0 User Manual
45
1: End of operation interrupt enable
11
Reserved
Must be kept at reset value
10
ERRIE
Error interrupt enable bit
This bit is set or cleared by software.
0: No interrupt generated by hardware
1: Error interrupt enable
9
OBWE
Option byte erase/program enable bit
This bit is set by hardware when right sequence written to FMC_OBKEY
register. This bit can be cleared by software.
8
Reserved
Must be kept at reset value
7
LK
FMC_CTL lock bit
This bit is cleared by hardware when right sequent written to FMC_KEY
register. This bit can be set by software.
6
START
Send erase command to FMC bit
This bit is set by software to send erase command to FMC. This bit is
cleared by hardware when the BUSY bit is cleared.
5
OBER
Option byte erase command bit
This bit is set or cleared by software.
0: No effect
1: Option byte erase command
4
OBPG
Option byte program command bit
This bit is set or cleared by software.
0: No effect
1: Option byte program command
3
Reserved
Must be kept at reset value
2
MER
Main flash mass erase command bit
This bit is set or cleared by software.
0: No effect
1: Main flash mass erase command
1
PER
Main flash page erase command bit
This bit is set or cleared by software.
0: No effect
1: Main flash page erase command
0
PG
Main flash page program command bit
This bit is set or cleared by software.
0: No effect
1: Main flash page program command
GD32F1x0 User Manual
46
3.4.6. Address register (FMC_ADDR)
Address offset: 0x14
Reset value: 0x0000 0080
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
ADDR[31:16]
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
ADDR[15:0]
rw
Bits
Fields
Descriptions
31:0
ADDR[31:0]
Flash command address bits
These bits are set by software.
ADDR bits are the address of flash erase command
3.4.7. Option byte status register (FMC_OBSTAT)
Address offset: 0x1C
Reset value: 0xXXXX XX0X
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
OB_DATA[15:0]
r
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
OB_USER[7:0]
Reserved
PLEVEL[1:0]
OBER
r
r
r
Bits
Fields
Descriptions
31:16
OB_DATA[15:0]
Store OB_DATA[15:0] of option byte block after system reset
15:8
OB_USER[7:0]
Store OB_USER byte of option byte block after system reset
2:1
PLEVEL[1:0]
Security Protection level
00: No protection level
01: Protect level low
11: Protect level high
0
OBER
Option byte read error bit.
This bit is set by hardware when the option byte and its complement byte
do not match, and the option byte set 0xFF.
GD32F1x0 User Manual
47
3.4.8. Write protection register (FMC_WP)
Address offset: 0x20
Reset value: 0x0000 XXXX
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
OB_WP[15:0]
r
Bits
Fields
Descriptions
31:16
Reserved
Must be kept at reset value
15:0
OB_WP[15:0]
Store OB_WP[15:0] of option byte block after system reset
0: Protection active
1: Unprotected
3.4.9. Wait state enable register (FMC_WSEN)
For GD32F130xx and GD32F150xx devices
Address offset: 0xFC
Reset value: 0xXXXX XXXX
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Resrved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
WSEN
rw
Bits
Fields
Descriptions
31:1
Reserved
Must be kept at reset value
0
WSEN
FMC wait state enable register
This bit set and reset by software. This bit also protected by the
FMC_KEY register. There need writing 0x45670123 and 0xCDEF89AB
to the FMC_KEY register.
0: No wait state added when fetching flash
1: Wait state added when fetching flash
GD32F1x0 User Manual
48
For GD32F170xx and GD32F190xx devices
Address offset: 0xFC
Reset value: 0x0000 0000
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Resrved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
BPE
N
WSE
N
rw
rw
Bits
Fields
Descriptions
31:2
Reserved
Must be kept at reset value
1
BPEN
FMC bit program enable register
This bit set and reset by software.
0: No effect, write page must check if flash is “FF”
1: Write page donot check the flash is FF. The FMC can program each
bit.
0
WSEN
FMC wait state enable register
This bit set and reset by software. This bit is also protected by the
FMC_KEY register. The software need writing 0x45670123 and
0xCDEF89AB to the FMC_KEY register.
0: No wait state added when fetching flash
1: Wait state added when fetching flash
3.4.10. Product ID register (FMC_PID)
Address offset: 0x100
Reset value: 0xXXXX XXXX
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
PID[31:16]
r
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
PID[15:0]
r
Bits
Fields
Descriptions
31:0
PID[31:0]
Product reserved ID code register1
GD32F1x0 User Manual
49
These bits are read only by software.
These bits are unchanged constantly after power on. These bits are one
time programmed when the chip product.
GD32F1x0 User Manual
50
4. Reset and clock unit (RCU)
4.1. Reset control unit (RCTL)
4.1.1. Introduction
GD32F1x0 Reset Control includes the control of three kinds of reset: power reset, system
reset and backup domain reset. The power on reset, known as a cold reset, resets the full
system except the Backup domain during a power up. A system reset resets the processor
core and peripheral IP components with the exception of the SW-DP controller and the
Backup domain. A backup domain reset resets the Backup domain. The resets can be
triggered by an external signal, internal events and the reset generators. More information
about these resets will be described in the following sections.
4.1.2. Function description
Power Reset
The Power reset is generated by either an external reset as Power On and Power Down reset
(POR/PDR reset), or by the internal reset generator when exiting Standby mode. The power
reset sets all registers to their reset values except the Backup domain. The Power reset which
active signal is low will be de-asserted when the internal LDO voltage regulator is ready to
provide 1.2V power for GD32F130/150xx devices or 1.8V power for GD32F170/190xx
devices power. The RESET service routine vector is fixed at address 0x0000_0004 in the
memory map.
System Reset
A system reset is generated by the following events:
A power on reset (PORRESETn)
A external pin reset (NRST)
A window watchdog timer reset (WWDGT_RSTn)
A free watchdog timer reset (FWDGT_RSTn)
The SYSRESETREQ bit in Cortex™-M3 Application Interrupt and Reset Control
Register is set (SW_RSTn)
Option byte loader reset (OBL_RSTn)
Reset generated when entering Standby mode when resetting OB_STDBY_RSTn bit in
User Option Bytes (OB_STDBY_RSTn)
Reset generated when entering Deep-sleep mode when resetting OB_DSLP_RSTn bit
in User Option Bytes (OB_DSLP_RSTn)
A system reset pulse generator guarantees low level pulse duration of 20 μs for each reset
source (external or internal reset).
GD32F1x0 User Manual
51
Figure 4-1. The system reset circuit
Filter
WWDGT_RSTn
FWDGT_RSTn
SW_RSTn
OB_STDBY_RSTn
OB_DEEPSLEEP_RSTn
PORRESETn
NRST
System Reset
min 20 us
pulse generator
OBL_RSTn
Backup domain reset
A backup domain reset is generated by setting the BKPRST bit in the Backup domain control
register or Backup domain power on reset (VDD or VBAT power on, if both supplies have
previously been powered off).
4.2. Clock control unit (CCTL)
4.2.1. Introduction
The Clock Control unit provides a range of frequencies and clock functions. These include a
Internal 8 MHz RC oscillator (IRC8M), a Internal 14 MHz RC oscillator (IRC14M) for
GD32F130xx and GD32F150xx devices or a Internal 28 MHz RC oscillator (IRC28M) for
GD32F170xx and GD32F190xx devices, a High speed crystal oscillator (HXTAL), Internal
40KHz RC oscillator (IRC40K), a Low speed crystal oscillator (LXTAL), a Phase Lock Loop
(PLL), a HXTAL clock monitor, clock prescalers, clock multiplexers and clock gating circuitry.
The clocks of the AHB, APB and Cortex™-M3 are derived from the system clock (CK_SYS)
which can source from the IRC8M, HXTAL or PLL. The maximum operating frequency of the
system clock (CK_SYS) can be up to 72 MHz. The Free Watchdog Timer has independent
clock source (IRC40K), and Real Time Clock (RTC) use the IRC40K, LXTAL or HXTAL/32 as
its clock source.
GD32F1x0 User Manual
52
Figure 4-2. Clock tree of GD32F130xx and GD32F150xx devices
/
2
4-32 MHz
HXTAL
8 MHz
IRC8M PLL
Clock
Monitor
PLLSEL
HXTALPRE
DV
PLLEN
0
1
00
01
1
0
CK_IRC8M
CK_HXTAL
CK_PLL CK_SYS
72 MHz max
AHB
Prescaler
÷1,2...512
CK_AHB
72 MHz max
APB1
Prescaler
÷1,2,4,8,16
TIMER1,2,5,1
3
÷[apb1
prescaler/2]
APB2
Prescaler
÷1,2,4,8,16
TIMER0,14,1
5,16
÷[apb2
prescaler/2]
ADC
Prescaler
÷2,4,6,8
CK_APB2
72 MHz max
Peripheral enable
PCLK2
to APB2 peripherals
CK_APB1
72 MHz max
Peripheral enable
PCLK1
to APB1 peripherals
TIMERx
enable
CK_TIMERx
to TIMER0,14,15,16
TIMERx
enable
CK_TIMERx
to TIMER1,2,5,13
CK_ADC to ADC
14 MHz max
AHB enable
HCLK
(to AHB bus,Cortex-M3,SRAM,DMA)
FMC enable
(by hardware)
CK_FMC
(to FMC)
÷8
CK_CST
(to Cortex-M3 SysTick)
FCLK
(free running clock)
USBD
Prescaler
÷1,1.5,2
CK_USB
(to USB)
32.768 KHz
LXTAL
11
10
0
1
40 KHz
IRC40K
CK_RTC
CK_FWDGT
(to RTC)
(to FWDGT)
/32
CK_ LXTAL
CK_PLL
CK_HXTAL
CK_IRC8M
CK_OUT
SCS[1:0
]
RTCSRC[1:0]
÷1,2.
..16
CK_I2S
(to I2S)
1
0
÷24
4
CK_CEC
(to CEC)
CK_ LXTAL
CECSEL
1
0
ADCSEL
14 MHz
IRC14M
11
00
01
10
CK_IRC8M
CK_LXTAL
CK_SYS
CK_USART0
to USART0
CK_SYS
CK_IRC40K
CK_IRC14M
0
*1,2
÷1,2,4...128
CKOUTDIV
GD32F1x0 User Manual
53
Figure 4-3. Clock tree of GD32F170xx and GD32F190xx devices
/
2
4-32 MHz
HXTAL
8 MHz
IRC8M PLL
Clock
Monitor
PLLSEL
HXTALPRE
DV
PLLEN
0
1
00
01
1
0
CK_IRC8M
CK_HXTAL
CK_PLL CK_SYS
72 MHz max
AHB
Prescaler
÷1,2...512
CK_AHB
72 MHz max
APB1
Prescaler
÷1,2,4,8,16
TIMER1,2,5,1
3
÷[apb1
prescaler/2]
APB2
Prescaler
÷1,2,4,8,16
TIMER0,14,1
5,16
÷[apb2
prescaler/2]
ADC
Prescaler
÷2,4,6,8
CK_APB2
72 MHz max
Peripheral enable
PCLK2
to APB2 peripherals
CK_APB1
72 MHz max
Peripheral enable
PCLK1
to APB1
peripherals
TIMERx
enable
CK_TIMERx
to
TIMER0,14,15,
16
TIMERx
enable
CK_TIMERx
to
TIMER1,2,5,13
CK_ADC to ADC
28 MHz max
AHB enable
HCLK
(to AHB bus,Cortex-M3,SRAM,DMA)
FMC enable
(by hardware)
CK_FMC
(to FMC)
÷8
CK_CST
(to Cortex-M3 SysTick)
FCLK
(free running clock)
32.768 KHz
LXTAL
11
10
0
1
40 KHz
IRC40K
CK_RTC(CK_SLCD)
CK_FWDGT
(to RTC or SLCD)
(to FWDGT)
/32
CK_LXTAL
CK_PLL
CK_HXTAL
CK_IRC8M
CK_OUT0
SCS[1:0
]
RTCSRC[1:0]
÷1,2.
..16
CK_I2S
(to I2S)
1
0
÷24
4
CK_CEC
(to CEC)
CK_LXTAL
CECSEL
1
0
ADCSEL
28 MHz
IRC28M
11
00
0
1
10
CK_IRC8M
CK_LXTAL
CK_SYS
CK_USART0
to USART0
CK_SYS
CK_IRC40K
CK_IRC28M
0
*1,2
÷1,2,4...128
CKOUT0DIV
CK_LXTAL
CK_PLL
CK_HXTAL
CK_IRC8M
CK_OUT1
CK_SYS
CK_IRC40K
CK_IRC28M
0
*1,2
÷1,2,3...64
CKOUT1DIV
÷1,2
The frequency of AHB, APB2 and the APB1 domains can be configured by each prescaler.
The maximum frequency of the AHB and the APB2/APB1 domains is 72 MHz. When using
I2Cx peripherals, APB1 clock need to ensure that no more than 36MHz.The Cortex System
Timer (SysTick) external clock is clocked with the AHB clock (HCLK) divided by 8. The
SysTick can work either with this clock or with the Cortex clock (HCLK), configurable in the
SysTick Control and Status Register.
The ADC is clocked by the clock of APB2 divided by 2, 4, 6, 8 or IRC14M clock selected for
GD32F130xx and GD32F150xx devices or 2, 4, 6, 8 or IRC28M or IRC28M/2 clock for
GD32F170xx and GD32F190xx devices selected by ADCSEL bit in Configuration register 2
(RCU_CFG2). The USART0 is clocked by IRC8M clock or LXTAL clock or system clock or
APB2 clock, which selected by USART0SEL bits in Configuration register 2 (RCU_CFG2).
The CEC clock is clocked by IRC8M divided 244 or LXTAL clock which selected by CECSEL
bit in Configuration register 2 (RCU_CFG2).
The RTC or SLCD (for GD32F170xx and GD32F190xx devices only) is clocked by LXTAL
GD32F1x0 User Manual
54
clock or IRC40K clock or HXTAL clock divided by 32 which select by RTCSRC bit in Backup
Domain Control Register (RCU_BDCTL).
The FWDGT is clocked by IRC40K clock, which is forced on when FWDGT started.
If the APB prescaler is 1, the timer clock frequencies are set to AHB frequency divide by 1.
Otherwise, they are set to the AHB frequency divide by half of APB prescaler.
4.2.2. Main features
4 to 32 MHz High speed crystal oscillator (HXTAL)
Internal 8 MHz RC oscillator (IRC8M)
Internal 14 MHz RC oscillator (IRC14M) for GD32F130xx and GD32F150xx devices or
Internal 28 MHz RC oscillator (IRC28M) for GD32F170xx and GD32F190xx devices
32,768 Hz Low speed crystal oscillator (LXTAL)
Internal 40KHz RC oscillator (IRC40K)
PLL clock source can be HXTAL or IRC8M
HXTAL clock monitor
4.2.3. Function description
High Speed Crystal Oscillator (HXTAL)
The high speed crystal oscillator (HXTAL), which has a frequency from 4 to 32 MHz, produces
a highly accurate clock source for use as the system clock. A crystal with a specific frequency
must be connected and located close to the two HXTAL pins. The external resistor and
capacitor components connected to the crystal are necessary for proper oscillation.
OSCIN OSCOUT
C1 C2
Crystal
The HXTAL crystal oscillator can be switched on or off using the HXTALEN bit in the Control
register 0, RCU_CTL0. The HXTALSTB flag in Control register 0, RCU_CTL0 indicates if the
high-speed external crystal oscillator is stable. When the HXTAL is powered up, it will not be
released for use until this HXTALSTB bit is set by the hardware. This specific delay period is
known as the oscillator “Start-up time”. As the HXTAL becomes stable, an interrupt will be
generated if the related interrupt enable bit HXTALSTBIE in the Interrupt register RCU_INT
is set. At this point the HXTAL clock can be used directly as the system clock source or the
PLL input clock.
GD32F1x0 User Manual
55
Select external clock bypass mode by setting the HXTALBPS and HXTALEN bits in the
Control register 0, RCU_CTL0. The CK_HXTAL is equal to the external clock which drives
the OSCIN pin.
Internal 8 MHz RC Oscillator (IRC8M)
The Internal 8 MHz RC oscillator, IRC8M, has a fixed frequency of 8 MHz and is the default
clock source selection for the CPU when the device is powered up. The IRC8M oscillator
provides a lower cost type clock source as no external components are required. The IRC8M
RC oscillator can be switched on or off using the IRC8MEN bit in the Control register 0,
RCU_CTL0. The IRC8MSTB flag in the Control register 0, RCU_CTL0 is used to indicate if
the internal RC oscillator is stable. The start-up time of the IRC8M oscillator is shorter than
the HXTAL crystal oscillator. An interrupt can be generated if the related interrupt enable bit,
IRC8MSTBIE, in the Interrupt register, RCU_INT, is set when the IRC8M becomes stable.
The IRC8M clock can also be used as the PLL input clock.
The frequency accuracy of the IRC8M can be calibrated by the manufacturer, but its operating
frequency is still less accurate than HXTAL. The application requirements, environment and
cost will determine which oscillator type is selected.
If the HXTAL or PLL is the system clock source, to minimize the time required for the system
to recover from the Deep-sleep Mode, the hardware forces the IRC8M clock to be the system
clock when the system initially wakes-up.
Phase Locked Loop (PLL)
The internal Phase Locked Loop, PLL, can provide 16~72 MHz clock output which is 2 ~32
multiples of a fundamental reference frequency of 4 ~ 32 MHz.
The PLL can be switched on or off by using the PLLEN bit in the Control register 0,
RCU_CTL0. The PLLSTB flag in the Control register 0, RCU_CTL0 will indicate if the PLL
clock is stable. An interrupt can be generated if the related interrupt enable bit, PLLSTBIE, in
the Interrupt register, RCU_INT, is set as the PLL becomes stable.
Internal 14 MHz RC Oscillator (IRC14M) for GD32F130xx and GD32F150xx devices
The Internal 14 MHz RC Oscillator, IRC14M, has a fixed frequency of 14 MHz and dedicated
as ADC clock. The IRC14M RC oscillator can be switched on or off using the IRC14MEN bit
in the Control register 1 (RCU_CTL1). The IRC14MSTB flag in the Control register 1
(RCU_CTL1) is used to indicate if the internal 14M RC oscillator is stable. An interrupt can
be generated if the related interrupt enable bit, IRC14MSTBIE, in the Interrupt register,
RCU_INT, is set when the IRC14M becomes stable.
Internal 28 MHz RC Oscillator (IRC28M) for GD32F170xx and GD32F190xx devices
The Internal 28 MHz RC Oscillator, IRC28M, has a fixed frequency of 28 MHz and dedicated
as ADC clock. The IRC28M RC oscillator can be switched on or off using the IRC28MEN bit
in the Control register 1 (RCU_CTL1). The IRC28MSTB flag in the Control register 1
(RCU_CTL1) is used to indicate if the internal 28M RC oscillator is stable. An interrupt can
GD32F1x0 User Manual
56
be generated if the related interrupt enable bit, IRC28MSTBIE, in the Interrupt register,
RCU_INT, is set when the IRC28M becomes stable.
Low Speed Crystal Oscillator (LXTAL)
The low speed crystal or ceramic resonator oscillator, which has a frequency of 32,768 Hz,
produces a low power but highly accurate clock source for the Real Time Clock circuit. The
LXTAL oscillator can be switched on or off using the LXTALEN bit in the Backup Domain
Control Register (RCU_BDCTL). The LXTALSTB flag in the Backup Domain Control Register
(RCU_BDCTL) will indicate if the LXTAL clock is stable. An interrupt can be generated if the
related interrupt enable bit, LXTALSTBIE, in the Interrupt register RCU_INT is set when the
LXTAL becomes stable.
Select external clock bypass mode by setting the LXTALBPS and LXTALEN bits in the
Backup Domain Control Register (RCU_BDCTL). The CK_LXTAL is equal to the external
clock which drives the OSC32IN pin.
Internal 40KHz RC Oscillator (IRC40K)
The Internal 40KHz RC Oscillator has a frequency of about 40 kHz and is a low power clock
source for the Real Time Clock circuit or the Free Watchdog Timer. The IRC40K offers a low
cost clock source as no external components are required. The IRC40K RC oscillator can be
switched on or off by using the IRC40KEN bit in the Reset Source/Clock Register,
RCU_RSTSCK. The IRC40KSTB flag in the Reset Source/Clock Register RCU_RSTSCK will
indicate if the IRC40K clock is stable. An interrupt can be generated if the related interrupt
enable bit IRC40KSTBIE in the Interrupt register RCU_INT is set when the IRC40K becomes
stable.
System Clock (CK_SYS) Selection
After the system reset, the default CK_SYS source will be IRC8M and can be switched to
HXTAL or PLL by changing the System Clock Switch bits, SCS, in the Configuration register
0, RCU_CFG0. When the SCS value is changed, the CK_SYS will continue to operate using
the original clock source until the target clock source is stable. When a clock source is used
directly by the CK_SYS or the PLL, it is not possible to stop it.
HXTAL Clock Monitor (CKM)
The HXTAL clock monitor function is enabled by the HXTAL Clock Monitor Enable bit,
CKMEN, in the Control register 0, RCU_CTL0. This function should be enabled after the
HXTAL start-up delay and disabled when the HXTAL is stopped. Once the HXTAL failure is
detected, the HXTAL will be automatically disabled. The HXTAL Clock Stuck Flag, CKMIF, in
the Interrupt register, RCU_INT, will be set and the HXTAL failure event will be generated.
This failure interrupt is connected to the Non-Maskable Interrupt, NMI, of the Cortex-M3. If
the HXTAL is selected as the clock source of CK_SYS or PLL, the HXTAL failure will force
the CK_SYS source to IRC8M and the PLL will be disabled automatically
Clock Output Capability
GD32F1x0 User Manual
57
For GD32F130xx and GD32F150xx devices
The clock output capability is ranging from 32 kHz to 54 MHz. There are several clock signals
can be selected via the CK_OUT Clock Source Selection bits, CKOUTSEL, in the
Configuration register 0 (RCU_CFG0). The corresponding GPIO pin should be configured in
the properly Alternate Function I/O (AFIO) mode to output the selected clock signal.
Table 4-1. Clock source select
Clock Source Selection bits
Clock Source
000
No Clock
001
CK_IRC14M
010
CK_IRC40K
011
CK_LXTAL
100
CK_SYS
101
CK_IRC8M
110
CK_HXTAL
111
CK_PLL or CK_PLL/2
The CK_OUT frequency can be reduced by a configurable binary divider, controlled by the
CKOUTDIV[2:0] bits , in the Configuration register 0 (RCU_CFG0).
For GD32F170xx and GD32F190xx devices
The clock output capability is ranging from 32 kHz to 54 MHz. There are several clock signals
can be selected via the CK_OUT0 Clock Source Selection bits, CKOUT0SEL, in the
Configuration register 0 (RCU_CFG0) and CKOUT1SRC in the Configuration register 3
(RCU_CFG3). The corresponding GPIO pin should be configured in the properly Alternate
Function I/O (AFIO) mode to output the selected clock signal.
Table 4-2. Clock source select
Clock Source Selection bits
Clock Source
000
No Clock
001
CK_IRC28M
010
CK_IRC40K
011
CK_LXTAL
100
CK_SYS
101
CK_IRC8M
110
CK_HXTAL
111
CK_PLL or CK_PLL/2
The CK_OUT0 frequency can be reduced by a configurable binary divider, controlled by the
CKOUT0DIV[2:0] bits , in the Configuration register 0 (RCU_CFG0).
The CK_OUT1 is seleced by CKOUT1SRC, in the Configuration register 3 (RCU_CFG3). The
CK_OUT1 frequency can be reduced by a configurable binary divider, controlled by the
CKOUT1DIV[2:0] bits , in the Configuration register 3 (RCU_CFG3).
Deep-sleep mode clock control
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58
When the MCU is in Deep-sleep mode, the HDMI CEC or USART0 can wake up the MCU,
when their clock is provided by LXTAL clock and LXTAL clock is enable.
If the HDMI CEC or USART0 clock is selected IRC8M clock in Deep-sleep mode, they have
capable of open IRC8M clock or close IRC8M clock, which used to the HDMI CEC or USART0
to wake up the Deep-sleep mode.
Voltage control
For GD32F130xx and GD32F150xx devices
The power down reset can be controlled by PDR_S bit in the Power down voltage select
register (RCU_PDVSEL). If the PDR_S bit is 0, the power down reset assert when the VDD is
below 2.6V. If the PDR_S bit is 1, the power down reset assert when the VDD is below 1.8V.
When the PDR_S bit is 1 and VDD is below 2.6V, the flash program/erase cannot be used.
The core domain voltage in Deep-sleep mode can be controlled by DSLPVS[2:0] bit in the
Deep-sleep mode voltage register (RCU_DSV).
Table 4-3. Core domain voltage selected in Deep-sleep mode -
DSLPVS[2:0]
Deep-sleep mode voltage(V)
000
1.2
001
1.1
010
1.0
011
0.9
100 ~ 111
reserved
The RCU_PDVSEL and RCU_DSV register are protected by Voltage Key register
(RCU_VKEY). Only after write 0x1A2B3C4D to the RCU_VKEY register, the RCU_PDVSEL
and RCU_DSV register can be write.
For GD32F170xx and GD32F190xx devices
The core domain voltage in Deep-sleep mode can be controlled by DSLPVS[2:0] bit in the
Deep-sleep mode voltage register (RCU_DSV).
Table 4-4. Core domain voltage selected in Deep-sleep mode -
DSLPVS[2:0]
Deep-sleep mode voltage(V)
000
1.8
001
1.6
010
1.4
011
1.2
100 ~ 111
reserved
The RCU_PDVSEL and RCU_DSV register are protected by Voltage Key register
(RCU_VKEY). Only after write 0x1A2B3C4D to the RCU_VKEY register, the RCU_PDVSEL
and RCU_DSV register can be write.
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4.3. RCU registers
4.3.1. Control register 0 (RCU_CTL0)
Address offset: 0x00
Reset value: 0x0000 XX83 where X is undefined.
This register can be accessed by byte(8-bit), half-word(16-bit) and word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
PLLSTB
PLL
EN
Reserved
CKMEN
HXTALBPS
HXTALSTB
HXTALEN
r
rw
rw
rw
r
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
IRC8MCALIB[7:0]
IRC8MADJ[4:0]
Reserved.
IRC8MSTB
IRC8MEN
r
rw
r
rw
Bits
Fields
Descriptions
31:26
Reserved
Must be kept at reset value.
25
PLLSTB
PLL Clock Stabilization Flag
Set by hardware to indicate if the PLL output clock is stable and ready for use.
0: PLL is not stable
1: PLL is stable
24
PLLEN
PLL enable
Set and reset by software. This bit cannot be reset if the PLL clock is used as the
system clock. Reset by hardware when entering Deep-sleep or Standby mode.
0: PLL is switched off
1: PLL is switched on
23:20
Reserved
Must be kept at reset value.
19
CKMEN
HXTAL Clock Monitor Enable
0: Disable the External 4 ~ 32 MHz crystal oscillator (HXTAL) clock monitor
1: Enable the External 4 ~ 32 MHz crystal oscillator (HXTAL) clock monitor
When the hardware detects that the HXTAL clock is stuck at a low or high state,
the internal hardware will switch the system clock to be the internal high speed
IRC8M RC clock. The way to recover the original system clock is by either an
external reset, power on reset or clearing CKMIF by software.
Note: When the HXTAL clock monitor is enabled, the hardware will automatically
enable the IRC8M internal RC oscillator regardless of the control bit, IRC8MEN,
state.
18
HXTALBPS
External crystal oscillator (HXTAL) clock bypass mode enable
The HXTALBPS bit can be written only if the HXTALEN is 0.
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0: Disable the HXTAL Bypass mode
1: Enable the HXTAL Bypass mode in which the HXTAL output clock is equal to
the input clock.
17
HXTALSTB
External crystal oscillator (HXTAL) clock stabilization flag
Set by hardware to indicate if the HXTAL oscillator is stable and ready for use.
0: HXTAL oscillator is not stable
1: HXTAL oscillator is stable
16
HXTALEN
External High Speed oscillator Enable
Set and reset by software. This bit cannot be reset if the HXTAL clock is used as
the system clock or the PLL input clock. Reset by hardware when entering Deep-
sleep or Standby mode.
0: External 4 ~ 32 MHz crystal oscillator disabled
1: External 4 ~ 32 MHz crystal oscillator enabled
15:8
IRC8MCALIB[7:0]
High Speed Internal Oscillator calibration value register
These bits are load automatically at power on.
7:3
IRC8MADJ[4:0]
High Speed Internal Oscillator clock trim adjust value
These bits are set by software. The trimming value is there bits (IRC8MADJ) added
to the IRC8MCALIB[7:0] bits. The trimming value should trim the IRC8M to 8 MHz
± 1%.
2
Reserved
Must be kept at reset value.
1
IRC8MSTB
IRC8M High Speed Internal Oscillator stabilization Flag
Set by hardware to indicate if the IRC8M oscillator is stable and ready for use.
0: IRC8M oscillator is not stable
1: IRC8M oscillator is stable
0
IRC8MEN
Internal High Speed oscillator Enable
Set and reset by software. This bit cannot be reset if the IRC8M clock is used as
the system clock. Set by hardware when leaving Deep-sleep or Standby mode or
the HXTAL clock is stuck at a low or high state when HXTALCKM is set.
0: Internal 8 MHz RC oscillator disabled
1: Internal 8 MHz RC oscillator enabled
4.3.2. Configuration register 0 (RCU_CFG0)
For GD32F130xx and GD32F150xx devices
Address offset: 0x04
Reset value: 0x0000 0000
This register can be accessed by byte(8-bit), half-word(16-bit) and word(32-bit)
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31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
PLLDV
CKOUTDIV[2:0]
PLLMF[4]
CKOUTSEL[2:0]
USBDPSC[1:0]
PLLMF[3:0]
PLLPREDV
PLLSEL
rw
rw
rw
rw
rw
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
ADCPSC[1:0]
APB2PSC[2:0]
APB1PSC[2:0]
AHBPSC[3:0]
SCSS[1:0]
SCS[1:0]
rw
rw
rw
rw
r
rw
Bits
Fields
Descriptions
31
PLLDV
The CK_PLL divide by 1 or 2 for CK_OUT
0: CK_PLL divide by 2 for CK_OUT
1: CK_PLL divide by 1 for CK_OUT
30:28
CKOUTDIV[2:0]
The CK_OUT divider which the CK_OUT frequency can be reduced
see bits 26:24 of RCU_CFG0 for CK_OUT.
000: The CK_OUT is divided by 1
001: The CK_OUT is divided by 2
010: The CK_OUT is divided by 4
011: The CK_OUT is divided by 8
100: The CK_OUT is divided by 16
101: The CK_OUT is divided by 32
110: The CK_OUT is divided by 64
111: The CK_OUT is divided by 128
27
PLLMF[4]
Bit 4 of PLLMF register
see bits 21:18 of RCU_CFG0.
26:24
CKOUTSEL[2:0]
CK_OUT Clock Source Selection
Set and reset by software.
000: No clock selected
001: Internal 14M RC oscillator clock selected
010: Internal 40K RC oscillator clock selected
011: External Low Speed oscillator clock selected
100: System clock selected
101: Internal 8MHz RC Oscillator clock selected
110: External High Speed oscillator clock selected
111: (CK_PLL / 2) or CK_PLL selected depend on PLLDV
23:22
USBDPSC[1:0]
USBD clock prescaler selection
Set and reset by software to control the USBD clock prescaler value. The USBD
clock must be 48MHz. These bits can’t be reset if the USBD clock is enabled.
00: (CK_PLL / 1.5) selected
01: CK_PLL selected
10: (CK_PLL / 2.5) selected
11: (CK_PLL / 2) selected
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62
21:18
PLLMF[3:0]
PLL multiply factor
These bits and bit 27 of RCU_CFG0 are written by software to define the PLL
multiplication factor.
00000: (PLL source clock x 2)
00001: (PLL source clock x 3)
00010: (PLL source clock x 4)
00011: (PLL source clock x 5)
00100: (PLL source clock x 6)
00101: (PLL source clock x 7)
00110: (PLL source clock x 8)
00111: (PLL source clock x 9)
01000: (PLL source clock x 10)
01001: (PLL source clock x 11)
01010: (PLL source clock x 12)
01011: (PLL source clock x 13)
01100: (PLL source clock x 14)
01101: (PLL source clock x 15)
01110: (PLL source clock x 16)
01111: (PLL source clock x 16)
10000: (PLL source clock x 17)
10001: (PLL source clock x 18)
10010: (PLL source clock x 19)
10011: (PLL source clock x 20)
10100: (PLL source clock x 21)
10101: (PLL source clock x 22)
10110: (PLL source clock x 23)
10111: (PLL source clock x 24)
11000: (PLL source clock x 25)
11001: (PLL source clock x 26)
11010: (PLL source clock x 27)
11011: (PLL source clock x 28)
11100: (PLL source clock x 29)
11101: (PLL source clock x 30)
11110: (PLL source clock x 31)
11111: (PLL source clock x 32)
Note: The PLL output frequency must not exceed 72 MHz.
17
PLLPREDV
HXTAL divider for PLL source clock selection. This bit is the same bit as bit
HXTALPREDV[0] from RCU_CFG1. Refer to RCU_CFG1 HXTALPREDV bits
description.
Set and cleared by software to divide HXTAL or not which is selected to PLL.
0: HXTAL clock selected
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1: (CK_HXTAL / 2) clock selected
16
PLLSEL
PLL Clock Source Selection
Set and reset by software to control the PLL clock source.
0: (CK_IRC8M / 2) selected as PLL source clock
1: HXTAL selected as PLL source clock
15:14
ADCPSC[1:0]
ADC clock prescaler selection
Set and cleared by software.
00: (CK_APB2 / 2) selected
01: (CK_ APB2 / 4) selected
10: (CK_ APB2 / 6) selected
11: (CK_ APB2 / 8) selected
13:11
APB2PSC[2:0]
APB2 prescaler selection
Set and reset by software to control the APB2 clock division ratio.
0xx: CK_AHB selected
100: (CK_AHB / 2) selected
101: (CK_AHB / 4) selected
110: (CK_AHB / 8) selected
111: (CK_AHB / 16) selected
10:8
APB1PSC[2:0]
APB1 prescaler selection
Set and reset by software to control the APB1 clock division ratio.
0xx: CK_AHB selected
100: (CK_AHB / 2) selected
101: (CK_AHB / 4) selected
110: (CK_AHB / 8) selected
111: (CK_AHB / 16) selected
7:4
AHBPSC[3:0]
AHB prescaler selection
Set and reset by software to control the AHB clock division ratio
0xxx: CK_SYS selected
1000: (CK_SYS / 2) selected
1001: (CK_SYS / 4) selected
1010: (CK_SYS / 8) selected
1011: (CK_SYS / 16) selected
1100: (CK_SYS / 64) selected
1101: (CK_SYS / 128) selected
1110: (CK_SYS / 256) selected
1111: (CK_SYS / 512) selected
3:2
SCSS[1:0]
System clock switch status
Set and reset by hardware to indicate the clock source of system clock.
00: select CK_IRC8M as the CK_SYS source
01: select CK_HXTAL as the CK_SYS source
10: select CK_PLL as the CK_SYS source
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11: reserved
1:0
SCS[1:0]
System clock switch
Set by software to select the CK_SYS source. Because the change of CK_SYS has
inherent latency, software should read SCSS to confirm whether the switching is
complete or not. The switch will be forced to IRC8M when leaving Deep-sleep and
Standby mode or by HXTAL clock monitor when the HXTAL failure is detected and
the HXTAL is selected as the clock source of CK_SYS or PLL.
00: select CK_IRC8M as the CK_SYS source
01: select CK_HXTAL as the CK_SYS source
10: select CK_PLL as the CK_SYS source
11: reserved
For GD32F170xx and GD32F190xx devices
Address offset: 0x04
Reset value: 0x0000 0000
This register can be accessed by byte(8-bit), half-word(16-bit) and word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
PLLDV
CKOUT0DIV[2:0]
PLLMF[4]
CKOUT0SEL [2:0]
Reserved
PLLMF[3:0]
PLLPREDV
PLLSEL
rw
rw
rw
rw
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
ADCPSC[1:0]
APB2PSC[2:0]
APB1PSC[2:0]
AHBPSC[3:0]
SCSS[1:0]
SCS[1:0]
rw
rw
rw
rw
r
rw
Bits
Fields
Descriptions
31
PLLDV
The CK_PLL divide by 1 or 2 for CK_OUT0
0: CK_PLL divide by 2 for CK_OUT0
1: CK_PLL divide by 1 for CK_OUT0
30:28
CKOUT0DIV[2:0]
The CK_OUT0 divider which the CK_OUT0 frequency can be reduced
see bits 26:24 of RCU_CFG0 for CK_OUT0
000: The CK_OUT0 is divided by 1
001: The CK_OUT0 is divided by 2
010: The CK_OUT0 is divided by 4
011: The CK_OUT0 is divided by 8
100: The CK_OUT0 is divided by 16
101: The CK_OUT0 is divided by 32
110: The CK_OUT0 is divided by 64
111: The CK_OUT0 is divided by 128
27
PLLMF[4]
Bit 4 of PLLMF register
see bits 21:18 of RCU_CFG0.
GD32F1x0 User Manual
65
26:24
CKOUT0SEL[2:0]
CKOUT0 Clock Source Selection
Set and reset by software.
000: No clock selected
001: Internal 28MHz RC oscillator clock selected
010: Internal 40K RC oscillator clock selected
011: External Low Speed oscillator clock selected
100: System clock selected
101: Internal 8MHz RC Oscillator clock selected
110: External High Speed oscillator clock selected
111: (CK_PLL / 2) or CK_PLL selected depend on PLLDV
23:22
Reserved
Must be kept at reset value.
21:18
PLLMF[3:0]
PLL multiply factor
These bits and bit 27 of RCU_CFG0 are written by software to define the PLL
multiplication factor.
00000: (PLL source clock x 2)
00001: (PLL source clock x 3)
00010: (PLL source clock x 4)
00011: (PLL source clock x 5)
00100: (PLL source clock x 6)
00101: (PLL source clock x 7)
00110: (PLL source clock x 8)
00111: (PLL source clock x 9)
01000: (PLL source clock x 10)
01001: (PLL source clock x 11)
01010: (PLL source clock x 12)
01011: (PLL source clock x 13)
01100: (PLL source clock x 14)
01101: (PLL source clock x 15)
01110: (PLL source clock x 16)
01111: (PLL source clock x 16)
10000: (PLL source clock x 17)
10001: (PLL source clock x 18)
10010: (PLL source clock x 19)
10011: (PLL source clock x 20)
10100: (PLL source clock x 21)
10101: (PLL source clock x 22)
10110: (PLL source clock x 23)
10111: (PLL source clock x 24)
11000: (PLL source clock x 25)
11001: (PLL source clock x 26)
11010: (PLL source clock x 27)
11011: (PLL source clock x 28)
11100: (PLL source clock x 29)
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11101: (PLL source clock x 30)
11110: (PLL source clock x 31)
11111: (PLL source clock x 32)
Note: The PLL output frequency must not exceed 72 MHz.
17
PLLPREDV
HXTAL divider for PLL source clock selection. This bit is the same bit as bit
HXTALPREDV[0] from RCU_CFG1. Refer to RCU_CFG1 HXTALPREDV bits
description.
Set and cleared by software to divide HXTAL or not which is selected to PLL.
0: HXTAL clock selected
1: (CK_HXTAL / 2) clock selected
16
PLLSEL
PLL Clock Source Selection
Set and reset by software to control the PLL clock source.
0: (CK_IRC8M / 2) selected as PLL source clock
1: HXTAL selected as PLL source clock
15:14
ADCPSC[1:0]
ADC clock prescaler selection
Set and cleared by software.
00: (CK_APB2 / 2) selected
01: (CK_APB2 / 4) selected
10: (CK_APB2 / 6) selected
11: (CK_APB2 / 8) selected
13:11
APB2PSC[2:0]
APB2 prescaler selection
Set and reset by software to control the APB2 clock division ratio.
0xx: CK_AHB selected
100: (CK_AHB / 2) selected
101: (CK_AHB / 4) selected
110: (CK_AHB / 8) selected
111: (CK_AHB / 16) selected
10:8
APB1PSC[2:0]
APB1 prescaler selection
Set and reset by software to control the APB1 clock division ratio.
0xx: CK_AHB selected
100: (CK_AHB / 2) selected
101: (CK_AHB / 4) selected
110: (CK_AHB / 8) selected
111: (CK_AHB / 16) selected
7:4
AHBPSC[3:0]
AHB prescaler selection
Set and reset by software to control the AHB clock division ratio
0xxx: CK_SYS selected
1000: (CK_SYS / 2) selected
1001: (CK_SYS / 4) selected
1010: (CK_SYS / 8) selected
1011: (CK_SYS / 16) selected
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1100: (CK_SYS / 64) selected
1101: (CK_SYS / 128) selected
1110: (CK_SYS / 256) selected
1111: (CK_SYS / 512) selected
3:2
SCSS[1:0]
System clock switch status
Set and reset by hardware to indicate the clock source of system clock.
00: select CK_IRC8M as the CK_SYS source
01: select CK_HXTAL as the CK_SYS source
10: select CK_PLL as the CK_SYS source
11: reserved
1:0
SCS[1:0]
System clock switch
Set by software to select the CK_SYS source. Because the change of CK_SYS has
inherent latency, software should read SCSS to confirm whether the switching is
complete or not. The switch will be forced to IRC8M when leaving Deep-sleep and
Standby mode or by HXTAL clock monitor when the HXTAL failure is detected and
the HXTAL is selected as the clock source of CK_SYS or PLL.
00: select CK_IRC8M as the CK_SYS source
01: select CK_HXTAL as the CK_SYS source
10: select CK_PLL as the CK_SYS source
11: reserved
4.3.3. Interrupt register (RCU_INT)
For GD32F130xx and GD32F150xx devices
Address offset: 0x08
Reset value: 0x0000 0000
This register can be accessed by byte(8-bit), half-word(16-bit) and word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
CKMIC
Reserved
IRC14M
STBIC
PLL
STBIC
HXTAL
STBIC
IRC8M
STBIC
LXTAL
STBIC
IRC40K
STBIC
w
w
w
w
w
w
w
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
IRC14M
STBIE
PLL
STBIE
HXTAL
STBIE
IRC8M
STBIE
LXTAL
STBIE
IRC40K
STBIE
CKMIF
Reserved
IRC14M
STBIF
PLL
STBIF
HXTAL
STBIF
IRC8M
STBIF
LXTAL
STBIF
IRC40K
STBIF
rw
rw
rw
rw
rw
rw
r
r
r
r
r
r
r
Bits
Fields
Descriptions
31:24
Reserved
Must be kept at reset value
23
CKMIC
HXTAL Clock Stuck Interrupt Clear
GD32F1x0 User Manual
68
Write 1 by software to reset the CKMIF flag.
0: Not reset CKMIF flag
1: Reset CKMIF flag
22
Reserved
Must be kept at reset value
21
IRC14MSTBIC
IRC14M stabilization Interrupt Clear
Write 1 by software to reset the IRC14MSTBIF flag.
0: Not reset IRC14MSTBIF flag
1: Reset IRC14MSTBIF flag
20
PLLSTBIC
PLL stabilization Interrupt Clear
Write 1 by software to reset the PLLSTBIF flag.
0: Not reset PLLSTBIF flag
1: Reset PLLSTBIF flag
19
HXTALSTBIC
HXTAL Stabilization Interrupt Clear
Write 1 by software to reset the HXTALSTBIF flag.
0: Not reset HXTALSTBIF flag
1: Reset HXTALSTBIF flag
18
IRC8MSTBIC
IRC8M Stabilization Interrupt Clear
Write 1 by software to reset the IRC8MSTBIF flag.
0: Not reset IRC8MSTBIF flag
1: Reset IRC8MSTBIF flag
17
LXTALSTBIC
LXTAL Stabilization Interrupt Clear
Write 1 by software to reset the LXTALSTBIF flag.
0: Not reset LXTALSTBIF flag
1: Reset LXTALRDYF flag
16
IRC40KSTBIC
IRC40K Stabilization Interrupt Clear
Write 1 by software to reset the IRC40KRDYF flag.
0: Not reset IRC40KSTBIF flag
1: Reset IRC40KRDYF flag
15:14
Reserved
Must be kept at reset value
13
IRC14MSTBIE
IRC14M Stabilization Interrupt Enable
Set and reset by software to enable/disable the IRC14M stabilization interrupt.
0: Disable the IRC14M stabilization interrupt
1: Enable the IRC14M stabilization interrupt
12
PLLSTBIE
PLL Stabilization Interrupt Enable
Set and reset by software to enable/disable the PLL stabilization interrupt.
0: Disable the PLL stabilization interrupt
1: Enable the PLL stabilization interrupt
11
HXTALSTBIE
HXTAL Stabilization Interrupt Enable
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Set and reset by software to enable/disable the HXTAL stabilization interrupt
0: Disable the HXTAL stabilization interrupt
1: Enable the HXTAL stabilization interrupt
10
IRC8MSTBIE
IRC8M Stabilization Interrupt Enable
Set and reset by software to enable/disable the IRC8M stabilization interrupt
0: Disable the IRC8M stabilization interrupt
1: Enable the IRC8M stabilization interrupt
9
LXTALSTBIE
LXTAL Stabilization Interrupt Enable
LXTAL stabilization interrupt enable/disable control
0: Disable the LXTAL stabilization interrupt
1: Enable the LXTAL stabilization interrupt
8
IRC40KSTBIE
IRC40K Stabilization interrupt enable
IRC40K stabilization interrupt enable/disable control
0: Disable the IRC40K stabilization interrupt
1: Enable the IRC40K stabilization interrupt
7
CKMIF
HXTAL Clock Stuck Interrupt Flag
Set by hardware when the HXTAL clock is stuck.
Reset by software when setting the CKMIC bit.
0: Clock operating normally
1: HXTAL clock stuck
6
Reserved
Must be kept at reset value
5
IRC14MSTBIF
IRC14M stabilization interrupt flag
Set by hardware when the IRC14M is stable and the IRC14MSTBIE bit is set.
Reset by software when setting the IRC14MSTBIC bit.
0: No IRC14M stabilization interrupt generated
1: IRC14M stabilization interrupt generated
4
PLLSTBIF
PLL stabilization interrupt flag
Set by hardware when the PLL is stable and the PLLSTBIE bit is set.
Reset by software when setting the PLLSTBIC bit.
0: No PLL stabilization interrupt generated
1: PLL stabilization interrupt generated
3
HXTALSTBIF
HXTAL stabilization interrupt flag
Set by hardware when the External 4 ~ 32 MHz crystal oscillator clock is stable and
the HXTALSTBIE bit is set.
Reset by software when setting the HXTALSTBIC bit.
0: No HXTAL stabilization interrupt generated
1: HXTAL stabilization interrupt generated
2
IRC8MSTBIF
IRC8M stabilization interrupt flag
Set by hardware when the Internal 8 MHz RC oscillator clock is stable and the
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IRC8MSTBIE bit is set.
Reset by software when setting the IRC8MSTBIC bit.
0: No IRC8M stabilization interrupt generated
1: IRC8M stabilization interrupt generated
1
LXTALSTBIF
LXTAL stabilization interrupt flag
Set by hardware when the External 32,768 Hz crystal oscillator clock is stable and the
LXTALSTBIE bit is set.
Reset by software when setting the LXTALSTBIC bit.
0: No LXTAL stabilization interrupt generated
1: LXTAL stabilization interrupt generated
0
IRC40KSTBIF
IRC40K stabilization interrupt flag
Set by hardware when the Internal 32kHz RC oscillator clock is stable and the
IRC40KSTBIE bit is set.
Reset by software when setting the IRC40KSTBIC bit.
0: No IRC40K stabilization clock ready interrupt generated
1: IRC40K stabilization interrupt generated
For GD32F170xx and GD32F190xx devices
Address offset: 0x08
Reset value: 0x0000 0000
This register can be accessed by byte(8-bit), half-word(16-bit) and word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
CKMIC
Reserved
IRC28M
STBIC
PLL
STBIC
HXTAL
STBIC
IRC8M
STBIC
LXTAL
STBIC
IRC40K
STBIC
w
w
w
w
w
w
w
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
IRC28M
STBIE
PLL
STBIE
HXTAL
STBIE
IRC8M
STBIE
LXTAL
STBIE
IRC40K
STBIE
CKMIF
Reserved
IRC28M
STBIF
PLL
STBIF
HXTAL
STBIF
IRC8M
STBIF
LXTAL
STBIF
IRC40K
STBIF
rw
rw
rw
rw
rw
rw
r
r
r
r
r
r
r
Bits
Fields
Descriptions
31:24
Reserved
Must be kept at reset value
23
CKMIC
HXTAL Clock Stuck Interrupt Clear
Write 1 by software to reset the CKMIF flag.
0: Not reset CKMIF flag
1: Reset CKMIF flag
22
Reserved
Must be kept at reset value
21
IRC28MSTBIC
IRC28M stabilization Interrupt Clear
Write 1 by software to reset the IRC28MSTBIF flag.
GD32F1x0 User Manual
71
0: Not reset IRC28MSTBIF flag
1: Reset IRC28MSTBIF flag
20
PLLSTBIC
PLL stabilization Interrupt Clear
Write 1 by software to reset the PLLSTBIF flag.
0: Not reset PLLSTBIF flag
1: Reset PLLSTBIF flag
19
HXTALSTBIC
HXTAL Stabilization Interrupt Clear
Write 1 by software to reset the HXTALSTBIF flag.
0: Not reset HXTALSTBIF flag
1: Reset HXTALSTBIF flag
18
IRC8MSTBIC
IRC8M Stabilization Interrupt Clear
Write 1 by software to reset the IRC8MSTBIF flag.
0: Not reset IRC8MSTBIF flag
1: Reset IRC8MSTBIF flag
17
LXTALSTBIC
LXTAL Stabilization Interrupt Clear
Write 1 by software to reset the LXTALSTBIF flag.
0: Not reset LXTALSTBIF flag
1: Reset LXTALRDYF flag
16
IRC40KSTBIC
IRC40K Stabilization Interrupt Clear
Write 1 by software to reset the IRC40KRDYF flag.
0: Not reset IRC40KSTBIF flag
1: Reset IRC40KRDYF flag
15:14
Reserved
Must be kept at reset value
13
IRC28MSTBIE
IRC28M Stabilization Interrupt Enable
Set and reset by software to enable/disable the IRC28M stabilization interrupt.
0: Disable the IRC28M stabilization interrupt
1: Enable the IRC28M stabilization interrupt
12
PLLSTBIE
PLL Stabilization Interrupt Enable
Set and reset by software to enable/disable the PLL stabilization interrupt.
0: Disable the PLL stabilization interrupt
1: Enable the PLL stabilization interrupt
11
HXTALSTBIE
HXTAL Stabilization Interrupt Enable
Set and reset by software to enable/disable the HXTAL stabilization interrupt
0: Disable the HXTAL stabilization interrupt
1: Enable the HXTAL stabilization interrupt
10
IRC8MSTBIE
IRC8M Stabilization Interrupt Enable
Set and reset by software to enable/disable the IRC8M stabilization interrupt
0: Disable the IRC8M stabilization interrupt
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1: Enable the IRC8M stabilization interrupt
9
LXTALSTBIE
LXTAL Stabilization Interrupt Enable
LXTAL stabilization interrupt enable/disable control
0: Disable the LXTAL stabilization interrupt
1: Enable the LXTAL stabilization interrupt
8
IRC40KSTBIE
IRC40K Stabilization interrupt enable
IRC40K stabilization interrupt enable/disable control
0: Disable the IRC40K stabilization interrupt
1: Enable the IRC40K stabilization interrupt
7
CKMIF
HXTAL Clock Stuck Interrupt Flag
Set by hardware when the HXTAL clock is stuck.
Reset by software when setting the CKMIC bit.
0: Clock operating normally
1: HXTAL clock stuck
6
Reserved
Must be kept at reset value
5
IRC28MSTBIF
IRC28M stabilization interrupt flag
Set by hardware when the IRC28M is stable and the IRC28MSTBIE bit is set.
Reset by software when setting the IRC28MSTBIC bit.
0: No IRC28M stabilization interrupt generated
1: IRC28M stabilization interrupt generated
4
PLLSTBIF
PLL stabilization interrupt flag
Set by hardware when the PLL is stable and the PLLSTBIE bit is set.
Reset by software when setting the PLLSTBIC bit.
0: No PLL stabilization interrupt generated
1: PLL stabilization interrupt generated
3
HXTALSTBIF
HXTAL stabilization interrupt flag
Set by hardware when the External 4 ~ 32 MHz crystal oscillator clock is stable and
the HXTALSTBIE bit is set.
Reset by software when setting the HXTALSTBIC bit.
0: No HXTAL stabilization interrupt generated
1: HXTAL stabilization interrupt generated
2
IRC8MSTBIF
IRC8M stabilization interrupt flag
Set by hardware when the Internal 8 MHz RC oscillator clock is stable and the
IRC8MSTBIE bit is set.
Reset by software when setting the IRC8MSTBIC bit.
0: No IRC8M stabilization interrupt generated
1: IRC8M stabilization interrupt generated
1
LXTALSTBIF
LXTAL stabilization interrupt flag
Set by hardware when the External 32.768KHz crystal oscillator clock is stable and
GD32F1x0 User Manual
73
the LXTALSTBIE bit is set.
Reset by software when setting the LXTALSTBIC bit.
0: No LXTAL stabilization interrupt generated
1: LXTAL stabilization interrupt generated
0
IRC40KSTBIF
IRC40K stabilization interrupt flag
Set by hardware when the Internal 40kHz RC oscillator clock is stable and the
IRC40KSTBIE bit is set.
Reset by software when setting the IRC40KSTBIC bit.
0: No IRC40K stabilization clock ready interrupt generated
1: IRC40K stabilization interrupt generated
4.3.4. APB2 reset register (RCU_APB2RST)
Address offset: 0x0C
Reset value: 0x0000 0000
This register can be accessed by byte(8-bit), half-word(16-bit) and word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
TIMER16
RST
TIMER15
RST
TIMER14
RST
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
USART0
RST
Res.
SPI0
RST
TIMER0
RST
Res.
ADC
RST
Reserved
CFG
RST
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31:19
Reserved
Must be kept at reset value
18
TIMER16RST
TIMER16 reset
This bit is set and reset by software.
0: No reset
1: Reset the TIMER16
17
TIMER15RST
TIMER15 reset
This bit is set and reset by software.
0: No reset
1: Reset the TIMER15
16
TIMER14RST
TIMER14 reset
This bit is set and reset by software.
0: No reset
1: Reset the TIMER14
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14
USART0RST
USART0 Reset
This bit is set and reset by software.
0: No reset
1: Reset the USART0
13
Reserved
Must be kept at reset value
12
SPI0RST
SPI0 Reset
This bit is set and reset by software.
0: No reset
1: Reset the SPI0
11
TIMER0RST
TIMER0 reset
This bit is set and reset by software.
0: No reset
1: Reset the TIMER0
10
Reserved
Must be kept at reset value
9
ADCRST
ADC reset
This bit is set and reset by software.
0: No reset
1: Reset the ADC
8:1
Reserved
Must be kept at reset value
0
CFGRST
System configuration reset
This bit is set and reset by software.
0: No reset
1: Reset System configuration
4.3.5. APB1 reset register (RCU_APB1RST)
For GD32F130xx and GD32F150xx devices
Address offset: 0x10
Reset value: 0x0000 0000
This register can be accessed by byte(8-bit), half-word(16-bit) and word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
CEC
RST
DAC
RST
PMU
RST
Reserved
USBD
RST
I2C1
RST
I2C0
RST
Reserved
USART
1RST
Res.
rw
rw
rw
rw
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
SPI2
SPI1
Reserved
WWDGT
Reserved
TIMER13
Reserved
TIMER5
Reserved
TIMER2
TIMER1
GD32F1x0 User Manual
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RST
RST
RST
RST
RST
RST
RST
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31
Reserved
Must be kept at reset value
30
CECRST
HDMI CEC reset
This bit is set and reset by software.
0: No reset
1: Reset hdmi cec unit
29
DACRST
DAC reset
This bit is set and reset by software.
0: No reset
1: Reset DAC unit
28
PMURST
Power control reset
This bit is set and reset by software.
0: No reset
1: Reset power control unit
27:24
Reserved
Must be kept at reset value
23
USBDRST
USBD reset
This bit is set and reset by software.
0: No reset
1: Reset USBD
22
I2C1RST
I2C1 reset
This bit is set and reset by software.
0: No reset
1: Reset I2C1
21
I2C0RST
I2C0 reset
This bit is set and reset by software.
0: No reset
1: Reset I2C0
20:18
Reserved
Must be kept at reset value
17
USART1RST
USART1 reset
This bit is set and reset by software.
0: No reset
1: Reset USART1
16
Reserved
Must be kept at reset value
15
SPI2RST
SPI2 reset
This bit is set and reset by software.
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76
0: No reset
1: Reset SPI2
14
SPI1RST
SPI1 reset
This bit is set and reset by software.
0: No reset
1: Reset SPI1
13:12
Reserved
Must be kept at reset value
11
WWDGTRST
Window watchdog timer reset
This bit is set and reset by software.
0: No reset
1: Reset window watchdog timer
10:9
Reserved
Must be kept at reset value
8
TIMER13RST
TIMER13 timer reset
This bit is set and reset by software.
0: No reset
1: Reset TIMER13 Timer
7:5
Reserved
Must be kept at reset value
4
TIMER5RST
TIMER5 timer reset
This bit is set and reset by software.
0: No reset
1: Reset TIMER5 Timer
3:2
Reserved
Must be kept at reset value
1
TIMER2RST
TIMER2 timer reset
This bit is set and reset by software.
0: No reset
1: Reset TIMER2 timer
0
TIMER1RST
TIMER1 timer reset
This bit is set and reset by software.
0: No reset
1: Reset TIMER1 timer
For GD32F170xx and GD32F190xx devices
Address offset: 0x10
Reset value: 0x0000 0000
This register can be accessed by byte(8-bit), half-word(16-bit) and word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
OPAIVREF
CEC
DAC
PMU
Reserved
CAN1
CAN0
Reserved
I2C1
I2C0
Reserved
USART
Reserved
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RST
RST
RST
RST
RST
RST
RST
RST
1RST
rw
rw
rw
rw
rw
rw
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
SPI2
RST
SPI1
RST
Reserved
WWDGT
RST
Reserved.
SLCDRST
TIMER13
RST
Reserved
TIMER5
RST
Reserved
TIMER2
RST
TIMER1
RST
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31
OPAIVREFRST
OPA and IVREF reset
This bit is set and reset by software.
0: No reset
1: Reset OPA unit
30
CECRST
HDMI CEC reset
This bit is set and reset by software.
0: No reset
1: Reset hdmi cec unit
29
DACRST
DAC reset
This bit is set and reset by software.
0: No reset
1: Reset DAC unit
28
PMURST
Power control reset
This bit is set and reset by software.
0: No reset
1: Reset power control unit
27
Reserved
Must be kept at reset value
26
CAN1RST
CAN1 reset
This bit is set and reset by software.
0: No reset
1: Reset CAN1
25
CAN0RST
CAN0 reset
This bit is set and reset by software.
0: No reset
1: Reset CAN0
24:23
Reserved
Must be kept at reset value
22
I2C1RST
I2C1 reset
This bit is set and reset by software.
0: No reset
1: Reset I2C1
GD32F1x0 User Manual
78
21
I2C0RST
I2C0 reset
This bit is set and reset by software.
0: No reset
1: Reset I2C0
20:18
Reserved
Must be kept at reset value
17
USART1RST
USART1 reset
This bit is set and reset by software.
0: No reset
1: Reset USART1
16
Reserved
Must be kept at reset value
15
SPI2RST
SPI2 reset
This bit is set and reset by software.
0: No reset
1: Reset SPI2
14
SPI1RST
SPI1 reset
This bit is set and reset by software.
0: No reset
1: Reset SPI1
13:12
Reserved
Must be kept at reset value
11
WWDGTRST
Window watchdog timer reset
This bit is set and reset by software.
0: No reset
1: Reset window watchdog timer
10
Reserved
Must be kept at reset value
9
SLCDRST
SLCD reset
This bit is set and reset by software.
0: No reset
1: Reset SLCD Timer
8
TIMER13RST
TIMER13 timer reset
This bit is set and reset by software.
0: No reset
1: Reset TIMER13 timer
7:5
Reserved
Must be kept at reset value
4
TIMER5RST
TIMER5 timer reset
This bit is set and reset by software.
0: No reset
1: Reset TIMER5 Timer
GD32F1x0 User Manual
79
3:2
Reserved
Must be kept at reset value
1
TIMER2RST
TIMER2 timer reset
This bit is set and reset by software.
0: No reset
1: Reset TIMER2 timer
0
TIMER1RST
TIMER1 timer reset
This bit is set and reset by software.
0: No reset
1: Reset TIMER1 timer
4.3.6. AHB enable register (RCU_AHBEN)
Address offset: 0x14
Reset value: 0x0000 0014
This register can be accessed by byte(8-bit), half-word(16-bit) and word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
TSIEN
Res.
PFEN
Res.
PDEN
PCEN
PBEN
PAEN
Res.
rw
rw
rw
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved.
CRCEN
Res.
FMCEN
Res.
SRAMEN
Res.
DMAEN
rw
rw
rw
rw
Bits
Fields
Descriptions
31:25
Reserved
Must be kept at reset value
24
TSIEN
TSI clock enable
This bit is set and reset by software.
0: Disabled TSI clock
1: Enabled TSI clock
23
Reserved
Must be kept at reset value
22
PFEN
GPIO port F clock enable
This bit is set and reset by software.
0: Disabled GPIO port F clock
1: Enabled GPIO port F clock
21
Reserved
Must be kept at reset value
20
PDEN
GPIO port D clock enable
This bit is set and reset by software.
0: Disabled GPIO port D clock
GD32F1x0 User Manual
80
1: Enabled GPIO port D clock
19
PCEN
GPIO port C clock enable
This bit is set and reset by software.
0: Disabled GPIO port C clock
1: Enabled GPIO port C clock
18
PBEN
GPIO port B clock enable
This bit is set and reset by software.
0: Disabled GPIO port B clock
1: Enabled GPIO port B clock
17
PAEN
GPIO port A clock enable
This bit is set and reset by software.
0: Disabled GPIO port A clock
1: Enabled GPIO port A clock
16:7
Reserved
Must be kept at reset value
6
CRCEN
CRC clock enable
This bit is set and reset by software.
0: Disabled CRC clock
1: Enabled CRC clock
5
Reserved
Must be kept at reset value
4
FMCEN
FMC clock enable
This bit is set and reset by software to enable/disable FMC clock during Sleep
mode.
0: Disabled FMC clock during Sleep mode
1: Enabled FMC clock during Sleep mode
3
Reserved
Must be kept at reset value
2
SRAMEN
SRAM interface clock enable
This bit is set and reset by software to enable/disable SRAM interface clock
during Sleep mode.
0: Disabled SRAM interface clock during Sleep mode.
1: Enabled SRAM interface clock during Sleep mode
1
Reserved
Must be kept at reset value
0
DMAEN
DMA clock enable
This bit is set and reset by software.
0: Disabled DMA clock
1: Enabled DMA clock
GD32F1x0 User Manual
81
4.3.7. APB2 enable register (RCU_APB2EN)
Address offset: 0x18
Reset value: 0x0000 0000
This register can be accessed by byte(8-bit), half-word(16-bit) and word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
TIMER16EN
TIMER15EN
TIMER14EN
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
USART0EN
Reserved
SPI0EN
TIMER0EN
Reserved
ADCEN
Reserved
CFGCMP
EN
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31:19
Reserved
Must be kept at reset value
18
TIMER16EN
TIMER16 timer clock enable
This bit is set and reset by software.
0: Disabled TIMER16 timer clock
1: Enabled TIMER16 timer clock
17
TIMER15EN
TIMER15 timer clock enable
This bit is set and reset by software.
0: Disabled TIMER15 timer clock
1: Enabled TIMER15 timer clock
16
TIMER14EN
TIMER14 timer clock enable
This bit is set and reset by software.
0: Disabled TIMER14 timer clock
1: Enabled TIMER14 timer clock
15
Reserved
Must be kept at reset value
14
USART0EN
USART0 clock enable
This bit is set and reset by software.
0: Disabled USART0 clock
1: Enabled USART0 clock
13
Reserved
Must be kept at reset value
12
SPI0EN
SPI0 clock enable
This bit is set and reset by software.
0: Disabled SPI0 clock
1: Enabled SPI0 clock
11
TIMER0EN
TIMER0 timer clock enable
GD32F1x0 User Manual
82
This bit is set and reset by software.
0: Disabled TIMER0 timer clock
1: Enabled TIMER0 timer clock
10
Reserved
Must be kept at reset value
9
ADCEN
ADC interface clock enable
This bit is set and reset by software.
0: Disabled ADC interface clock
1: Enabled ADC interface clock
8:1
Reserved
Must be kept at reset value
0
CFGCMPEN
System configuration and comparator clock enable
This bit is set and reset by software.
0: Disabled System configuration and comparator clock
1: Enabled System configuration and comparator clock
4.3.8. APB1 enable register (RCU_APB1EN)
For GD32F130xx and GD32F150xx devices
Address offset: 0x1C
Reset value: 0x0000 0000
This register can be accessed by byte(8-bit), half-word(16-bit) and word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
CECEN
DACEN
PMUEN
Reserved
USBDEN
I2C1EN
I2C0EN
Reserved
USART1EN
Reserved
rw
rw
rw
rw
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
SPI2EN
SPI1EN
Reserved
WWDGTEN
Reserved
TIMER13EN
Reserved
TIMER5EN
Reserved
TIMER2EN
TIMER1EN
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31
Reserved
Must be kept at reset value
30
CECEN
Hdmi cec interface clock enable
This bit is set and reset by software.
0: Disabled Hdmi cec interface clock
1: Enabled Hdmi cec interface clock
29
DACEN
DAC interface clock enable
This bit is set and reset by software.
0: Disabled DAC interface clock
1: Enabled DAC interface clock
GD32F1x0 User Manual
83
28
PMUEN
Power interface clock enable
This bit is set and reset by software.
0: Disabled Power interface clock
1: Enabled Power interface clock
27:24
Reserved
Must be kept at reset value
23
USBDEN
USBD clock enable
This bit is set and reset by software.
0: Disabled USBD clock
1: Enabled USBD clock
22
I2C1EN
I2C1 clock enable
This bit is set and reset by software.
0: Disabled I2C1 clock
1: Enabled I2C1 clock
21
I2C0EN
I2C0 clock enable
This bit is set and reset by software.
0: Disabled I2C0 clock
1: Enabled I2C0 clock
20:18
Reserved
Must be kept at reset value
17
USART1EN
USART1 clock enable
This bit is set and reset by software.
0: Disabled USART1 clock
1: Enabled USART1 clock
16
Reserved
Must be kept at reset value
15
SPI2EN
SPI2 clock enable
This bit is set and reset by software.
0: Disabled SPI2 clock
1: Enabled SPI2 clock
14
SPI1EN
SPI1 clock enable
This bit is set and reset by software.
0: Disabled SPI1 clock
1: Enabled SPI1 clock
13:12
Reserved
Must be kept at reset value
11
WWDGTEN
Window watchdog timer clock enable
This bit is set and reset by software.
0: Disabled Window watchdog timer clock
1: Enabled Window watchdog timer clock
10:9
Reserved
Must be kept at reset value
GD32F1x0 User Manual
84
8
TIMER13EN
TIMER13 timer clock enable
This bit is set and reset by software.
0: Disabled TIMER13 timer clock
1: Enabled TIMER13 timer clock
7:5
Reserved
Must be kept at reset value
4
TIMER5EN
TIMER5 timer clock enable
This bit is set and reset by software.
0: Disabled TIMER5 timer clock
1: Enabled TIMER5 timer clock
3:2
Reserved
Must be kept at reset value
1
TIMER2EN
TIMER2 timer clock enable
This bit is set and reset by software.
0: Disabled TIMER2 timer clock
1: Enabled TIMER2 timer clock
0
TIMER1EN
TIMER1 timer clock enable
This bit is set and reset by software.
0: Disabled TIMER1 timer clock
1: Enabled TIMER1 timer clock
For GD32F170xx and GD32F190xx devices
Address offset: 0x1C
Reset value: 0x0000 0000
This register can be accessed by byte(8-bit), half-word(16-bit) and word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
OPAIVREFEN
CECEN
DACEN
PMUEN
Reserved
CAN1EN
CAN0EN
Reserved
I2C1EN
I2C0EN
Reserved
USART1EN
Reserved
rw
rw
rw
rw
rw
rw
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
SPI2EN
SPI1EN
Reserved
WWDGTE
N
Res.
SLCDEN
TIMER13EN
Reserved
TIMER5EN
Reserved
TIMER2EN
TIMER1EN
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31
OPAIVREFEN
OPA and IVREF clock enable
This bit is set and reset by software.
0: Disabled OPA and IVREF interface clock
1: Enabled OPA and IVREF interface clock
30
CECEN
Hdmi cec interface clock enable
This bit is set and reset by software.
GD32F1x0 User Manual
85
0: Disabled Hdmi cec interface clock
1: Enabled Hdmi cec interface clock
29
DACEN
DAC interface clock enable
This bit is set and reset by software.
0: Disabled DAC interface clock
1: Enabled DAC interface clock
28
PMUEN
Power interface clock enable
This bit is set and reset by software.
0: Disabled Power interface clock
1: Enabled Power interface clock
27
Reserved
Must be kept at reset value
26
CAN1EN
CAN1 clock enable
This bit is set and reset by software.
0: Disabled CAN1 clock
1: Enabled CAN1 clock
25
CAN0EN
CAN0 clock enable
This bit is set and reset by software.
0: Disabled CAN0 clock
1: Enabled CAN0 clock
24:23
Reserved
Must be kept at reset value
22
I2C1EN
I2C1 clock enable
This bit is set and reset by software.
0: Disabled I2C1 clock
1: Enabled I2C1 clock
21
I2C0EN
I2C0 clock enable
This bit is set and reset by software.
0: Disabled I2C0 clock
1: Enabled I2C0 clock
20:18
Reserved
Must be kept at reset value
17
USART1EN
USART1 clock enable
This bit is set and reset by software.
0: Disabled USART1 clock
1: Enabled USART1 clock
16
Reserved
Must be kept at reset value
15
SPI2EN
SPI2 clock enable
This bit is set and reset by software.
0: Disabled SPI2 clock
GD32F1x0 User Manual
86
1: Enabled SPI2 clock
14
SPI1EN
SPI1 clock enable
This bit is set and reset by software.
0: Disabled SPI1 clock
1: Enabled SPI1 clock
13:12
Reserved
Must be kept at reset value
11
WWDGTEN
Window watchdog timer clock enable
This bit is set and reset by software.
0: Disabled Window watchdog timer clock
1: Enabled Window watchdog timer clock
10
Reserved
Must be kept at reset value
9
SLCDEN
SLCD clock enable
This bit is set and reset by software.
0: Disabled SLCD clock
1: Enabled SLCD clock
8
TIMER13EN
TIMER13 timer clock enable
This bit is set and reset by software.
0: Disabled TIMER13 timer clock
1: Enabled TIMER13 timer clock
7:5
Reserved
Must be kept at reset value
4
TIMER5EN
TIMER5 timer clock enable
This bit is set and reset by software.
0: Disabled TIMER5 timer clock
1: Enabled TIMER5 timer clock
3:2
Reserved
Must be kept at reset value
1
TIMER2EN
TIMER2 timer clock enable
This bit is set and reset by software.
0: Disabled TIMER2 timer clock
1: Enabled TIMER2 timer clock
0
TIMER1EN
TIMER1 timer clock enable
This bit is set and reset by software.
0: Disabled TIMER1 timer clock
1: Enabled TIMER1 timer clock
GD32F1x0 User Manual
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4.3.9. Backup domain control register (RCU_BDCTL)
For GD32F130xx and GD32F150xx devices
Address offset: 0x20
Reset value: 0x0000 0018, reset by Backup domain Reset.
This register can be accessed by byte(8-bit), half-word(16-bit) and word(32-bit)
Note: The LXTALEN, LXTALBPS, RTCSRC and RTCEN bits of the Backup domain control
register (BDCTL) are only reset after a Backup domain Reset. These bits can be modified
only when the BKPWEN bit in the Power control register (PMU_CTL) has to be set.
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
BKPRST
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RTCEN
Reserved
RTCSRC[1:0]
Reserved
LXTALDRI[1:0]
LXTALBPS
LXTALSTB
LXTALEN
rw
rw
rw
rw
r
rw
Bits
Fields
Descriptions
31:17
Reserved
Must be kept at reset value
16
BKPRST
Backup domain reset
This bit is set and reset by software.
0: No reset
1: Resets Backup domain
15
RTCEN
RTC clock enable
This bit is set and reset by software.
0: Disabled RTC clock
1: Enabled RTC clock
14:10
Reserved
Must be kept at reset value
9:8
RTCSRC[1:0]
RTC clock entry selection
Set and reset by software to control the RTC clock source.
00: No clock selected
01: CK_LXTAL selected as RTC source clock
10: CK_IRC40K selected as RTC source clock
11: (CK_HXTAL / 32) selected as RTC source clock
7:5
Reserved
Must be kept at reset value
4:3
LXTALDRI[1:0]
LXTAL drive capability
Set and reset by software. Backup domain reset reset this value.
00: lower driving capability
GD32F1x0 User Manual
88
01: medium low driving capability
10: medium high driving capability
11: higher driving capability (reset value)
Note: The LXTALDRI is not in bypass mode.
2
LXTALBPS
LXTAL bypass mode enable
Set and reset by software.
0: Disable the LXTAL Bypass mode
1: Enable the LXTAL Bypass mode
1
LXTALSTB
External low-speed oscillator stabilization
Set by hardware to indicate if the LXTAL output clock is stable and ready for use.
0: LXTAL is not stable
1: LXTAL is stable
0
LXTALEN
LXTAL enable
Set and reset by software.
0: Disable LXTAL
1: Enable LXTAL
For GD32F170xx and GD32F190xx devices
Address offset: 0x20
Reset value: 0x0000 0018, reset by Backup domain Reset.
This register can be accessed by byte(8-bit), half-word(16-bit) and word(32-bit)
Note: The LXTALEN, LXTALBPS, RTCSRC and RTCEN bits of the Backup domain control
register (BDCTL) are only reset after a Backup domain Reset. These bits can be modified
only when the BKPWEN bit in the Power control register (PMU_CTL) has to be set.
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
BKPRST
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RTCEN
Reserved
RTCSRC[1:0]
Reserved
LXTALDRI[1:0]
LXTALBPS
LXTALSTB
LXTALEN
rw
rw
rw
rw
r
rw
Bits
Fields
Descriptions
31:17
Reserved
Must be kept at reset value
16
BKPRST
Backup domain reset
This bit is set and reset by software.
0: No reset
1: Resets Backup domain
15
RTCEN
RTC clock enable
GD32F1x0 User Manual
89
This bit is set and reset by software.
0: Disabled RTC clock
1: Enabled RTC clock
14:10
Reserved
Must be kept at reset value
9:8
RTCSRC[1:0]
RTC and SLCD clock entry selection
Set and reset by software to control the RTC and SLCD clock source. Once the RTC
and SLCD clock source has been selected, it cannot be changed anymore unless
the Backup domain is reset.
00: No clock selected
01: CK_LXTAL selected as RTC/SLCD source clock
10: CK_IRC40K selected as RTC/SLCD source clock
11: (CK_HXTAL / 32) selected as RTC/SLCD source clock
7:5
Reserved
Must be kept at reset value
4:3
LXTALDRI[1:0]
LXTAL drive capability
Set and reset by software. Backup domain reset reset this value.
00: lower driving capability
01: medium low driving capability
10: medium high driving capability
11: higher driving capability (reset value)
Note: The LXTALDRI is not in bypass mode.
2
LXTALBPS
LXTAL bypass mode enable
Set and reset by software.
0: Disable the LXTAL Bypass mode
1: Enable the LXTAL Bypass mode
1
LXTALSTB
External low-speed oscillator stabilization
Set by hardware to indicate if the LXTAL output clock is stable and ready for use.
0: LXTAL is not stable
1: LXTAL is stable
0
LXTALEN
LXTAL enable
Set and reset by software.
0: Disable LXTAL
1: Enable LXTAL
4.3.10. Reset source /clock register (RCU_RSTSCK)
Address offset: 0x24
Reset value: 0x0C00 0000, reset flags reset by power Reset only, other reset by system
reset.
This register can be accessed by byte(8-bit), half-word(16-bit) and word(32-bit)
GD32F1x0 User Manual
90
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
LP
RSTF
WWDGT
RSTF
FWDGT
RSTF
SW
RSTF
POR
RSTF
EP
RSTF
OBL
RSTF
RSTFC
V12
RSTF
Reserved
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
IRC40K
STB
IRC40K
EN
r
rw
Bits
Fields
Descriptions
31
LPRSTF
Low-power reset flag
Set by hardware when Deep-sleep /standby reset generated.
Reset by writing 1 to the RSTFC bit.
0: No Low-power management reset generated
1: Low-power management reset generated
30
WWDGTRSTF
Window watchdog timer reset flag
Set by hardware when a window watchdog timer reset generated.
Reset by writing 1 to the RSTFC bit.
0: No window watchdog reset generated
1: Window watchdog reset generated
29
FWDGTRSTF
Free Watchdog timer reset flag
Set by hardware when a Free Watchdog timer generated.
Reset by writing 1 to the RSTFC bit.
0: No Free Watchdog timer reset generated
1: Free Watchdog timer reset generated
28
SWRSTF
Software reset flag
Set by hardware when a software reset generated.
Reset by writing 1 to the RSTFC bit.
0: No software reset generated
1: Software reset generated
27
PORRSTF
Power reset flag
Set by hardware when a Power reset generated.
Reset by writing 1 to the RSTFC bit.
0: No Power reset generated
1: Power reset generated
26
EPRSTF
External PIN reset flag
Set by hardware when an External PIN generated.
Reset by writing 1 to the RSTFC bit.
0: No External PIN reset generated
1: External PIN reset generated
GD32F1x0 User Manual
91
25
OBLRSTF
Option byte loader reset flag
Set by hardware when an option byte loader generated.
Reset by writing 1 to the RSTFC bit.
0: No Option byte loader reset generated
1: Option byte loader reset generated
24
RSTFC
Reset flag clear
This bit is set by software to clear all reset flags.
0: Not clear reset flags
1: Clear reset flags
23
V12RSTF
V12 domain Power reset flag
Set by hardware when a V12 domain Power reset generated.
Reset by writing 1 to the RSTFC bit.
0: No V12 domain Power reset generated
1: V12 domain Power reset generated
22:2
Reserved
Must be kept at reset value
1
IRC40KSTB
IRC40K stabilization
Set by hardware to indicate if the IRC40K output clock is stable and ready for use.
0: IRC40K is not stable
1: IRC40K is stable
0
IRC40KEN
IRC40K enable
Set and reset by software.
0: Disable IRC40K
1: Enable IRC40K
4.3.11. AHB reset register (RCU_AHBRST)
Address offset: 0x28
Reset value: 0x0000 0000
This register can be accessed by byte(8-bit), half-word(16-bit) and word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
TSIRST
Reserved
PFRST
Reserved
PDRST
PCRST
PBRST
PARST
Reserved
rw
rw
rw
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved.
Bits
Fields
Descriptions
31:25
Reserved
Must be kept at reset value
24
TSIRST
TSI unit reset
GD32F1x0 User Manual
92
This bit is set and reset by software.
0: No reset TSI unit
1: Reset TSI unit
23
Reserved
Must be kept at reset value
22
PFRST
GPIO port F reset
This bit is set and reset by software.
0: No reset GPIO port F
1: Reset GPIO port F
21
Reserved
Must be kept at reset value
20
PDRST
GPIO port D reset
This bit is set and reset by software.
0: No reset GPIO port D
1: Reset GPIO port D
19
PCRST
GPIO port C reset
This bit is set and reset by software.
0: No reset GPIO port C
1: Reset GPIO port C
18
PBRST
GPIO port B reset
This bit is set and reset by software.
0: No reset GPIO port B
1: Reset GPIO port B
17
PARST
GPIO port A reset
This bit is set and reset by software.
0: No reset GPIO port A
1: Reset GPIO port A
16:0
Reserved
Must be kept at reset value
4.3.12. Configuration register 1 (RCU_CFG1)
Address offset: 0x2c
Reset value: 0x0000 0000
This register can be accessed by byte(8-bit), half-word(16-bit) and word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
HXTALPREDV[3:0]
rw
GD32F1x0 User Manual
93
Bits
Fields
Descriptions
31:4
Reserved
Must be kept at reset value
3:0
HXTALPREDV[3:0]
CK_HXTAL divider previous PLL
This bit is set and reset by software. These bits can be written when PLL is
disable
Note: The bit 0 of HXTALPREDV is same as bit 17 of RCU_CFG0, so modifying
bit 17 of RCU_CFG0 aslo modifies bit 0 of RCU_CFG2.
The CK_HXTAL is divided by (HXTALPREDV + 1).
0000: HXTAL input to PLL not divided
0001: HXTAL input to PLL divided by 2
0010: HXTAL input to PLL divided by 3
0011: HXTAL input to PLL divided by 4
0100: HXTAL input to PLL divided by 5
0101: HXTAL input to PLL divided by 6
0110: HXTAL input to PLL divided by 7
0111: HXTAL input to PLL divided by 8
1000: HXTAL input to PLL divided by 9
1001: HXTAL input to PLL divided by 10
1010: HXTAL input to PLL divided by 11
1011: HXTAL input to PLL divided by 12
1100: HXTAL input to PLL divided by 13
1101: HXTAL input to PLL divided by 14
1110: HXTAL input to PLL divided by 15
1111: HXTAL input to PLL divided by 16
4.3.13. Configuration register 2 (RCU_CFG2)
For GD32F130xx and GD32F150xx devices
Address offset: 0x30
Reset value: 0x0000 0000
This register can be accessed by byte(8-bit), half-word(16-bit) and word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
ADCSEL
Reserved
CECSEL
Reserved
USART0SEL[1:0]
rw
rw
rw
Bits
Fields
Descriptions
GD32F1x0 User Manual
94
31:9
Reserved
Must be kept at reset value
8
ADCSEL
CK_ADC clock source selection
This bit is set and reset by software.
0: CK_ADC select CK_IRC14M
1: CK_ADC select CK_APB2 which is divided by 2/4/6/8.
7
Reserved
Must be kept at reset value
6
CECSEL
CK_CEC clock source selection
This bit is set and reset by software.
0: CK_CEC select CK_IRC8M divided by 244
1: CK_CEC select CK_LXTAL
5:2
Reserved
Must be kept at reset value
1:0
USART0SEL[1:0]
CK_USART0 clock source selection
This bit is set and reset by software.
00: CK_USART0 select CK_APB2
01: CK_USART0 select CK_SYS
10: CK_USART0 select CK_LXTAL
11: CK_USART0 select CK_IRC8M
For GD32F170xx and GD32F190xx devices
Address offset: 0x30
Reset value: 0x0000 0000
This register can be accessed by byte(8-bit), half-word(16-bit) and word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
IRC28MDIV
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
ADCSEL
Reserved
CECSEL
Reserved
USART0SEL[1:0]
rw
rw
rw
Bits
Fields
Descriptions
31:17
Reserved
Must be kept at reset value
16
IRC28MDIV
CK_IRC28M divider 2 or not
This bit is set and reset by software.
0: IRC28M/2 select to ADC clock
1: IRC28M select to ADC clock.
15:9
Reserved
Must be kept at reset value
8
ADCSEL
CK_ADC clock source selection
This bit is set and reset by software.
GD32F1x0 User Manual
95
0: CK_ADC select CK_IRC28M or CK_IRC28M/2 set by IRC28MDIV
1: CK_ADC select CK_APB2 which is divided by 2/4/6/8.
7
Reserved
Must be kept at reset value
6
CECSEL
CK_CEC clock source selection
This bit is set and reset by software.
0: CK_CEC select CK_IRC8M divided by 244
1: CK_CEC select CK_LXTAL
5:2
Reserved
Must be kept at reset value
1:0
USART0SEL[1:0]
CK_USART0 clock source selection
This bit is set and reset by software.
00: CK_USART0 select CK_APB2
01: CK_USART0 select CK_SYS
10: CK_USART0 select CK_LXTAL
11: CK_USART0 select CK_IRC8M
4.3.14. Control register 1 (RCU_CTL1)
For GD32F130xx and GD32F150xx devices
Address offset: 0x34
Reset value: 0x0000 XX80 where X is undefined.
This register can be accessed by byte(8-bit), half-word(16-bit) and word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
IRC14MCALIB[7:0]
IRC14MADJ[4:0]
Reserved
IRC14MSTB
IRC14MEN
r
rw
r
rw
Bits
Fields
Descriptions
31:16
Reserved
Must be kept at reset value
15:8
IRC14MCALIB[7:0]
Internal 14M RC Oscillator calibration value register
These bits are load automatically at power on.
7:3
IRC14MADJ[4:0]
Internal 14M RC Oscillator clock trim adjust value
These bits are set by software. The trimming value is there bits (IRC14MADJ)
added to the IRC14MCALIB[7:0] bits. The trimming value should trim the IRC14M
to 14 MHz ± 1%.
2
Reserved
Must be kept at reset value
GD32F1x0 User Manual
96
1
IRC14MSTB
IRC14M Internal 14M RC Oscillator stabilization Flag
Set by hardware to indicate if the IRC14M oscillator is stable and ready for use.
0: IRC14M oscillator is not stable
1: IRC14M oscillator is stable
0
IRC14MEN
IRC14M Internal 14M RC oscillator Enable
Set and reset by software.
0: Internal 14 MHz RC oscillator disabled
1: Internal 14 MHz RC oscillator enabled
For GD32F170xx and GD32F190xx devices
Address offset: 0x34
Reset value: 0x0000 XX80 where X is undefined.
This register can be accessed by byte(8-bit), half-word(16-bit) and word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
IRC28MCALIB[7:0]
IRC28MADJ[4:0]
Reserved
IRC28MSTB
IRC28MEN
r
rw
r
rw
Bits
Fields
Descriptions
31:16
Reserved
Must be kept at reset value
15:8
IRC28MCALIB[7:0]
Internal 28MHz RC Oscillator calibration value register
These bits are load automatically at power on.
7:3
IRC28MADJ[4:0]
Internal 28MHz RC Oscillator clock trim adjust value
These bits are set by software. The trimming value is there bits (IRC28MADJ)
added to the IRC28MCALIB[7:0] bits. The trimming value should trim the IRC28M
to 28 MHz ± 1%.
2
Reserved
Must be kept at reset value.
1
IRC28MSTB
IRC28M Internal 28M RC Oscillator stabilization Flag
Set by hardware to indicate if the IRC28M oscillator is stable and ready for use.
0: IRC28M oscillator is not stable
1: IRC28M oscillator is stable
0
IRC28MEN
IRC28M Internal 28M RC oscillator Enable
Set and reset by software.
0: Internal 28MHz RC oscillator disabled
1: Internal 28 MHz RC oscillator enabled
GD32F1x0 User Manual
97
4.3.15. Configuration register 3 (RCU_CFG3) of GD32F170xx and GD32F190xx
devices
Address offset: 0x80
Reset value: 0x0000 0000
This register can be accessed by byte(8-bit), half-word(16-bit) and word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
CKOUT1DIV[5:0]
Reserved
CKOUT1SRC[2:0]
rw
rw
Bits
Fields
Descriptions
31:14
Reserved
Must be kept at reset value
13:8
CKOUT1DIV[5:0]
The CK_OUT1 divider which the CK_OUT1 frequency can be reduced
see bits 2:0 of RCU_CFG3 for CK_OUT1
0: The CK_OUT1 is divided by 1
1: The CK_OUT1 is divided by 2
2: The CK_OUT1 is divided by 3
…
63: The CK_OUT1 is divided by 64
7:3
Reserved
Must be kept at reset value
2:0
CKOUT1SRC[2:0]
CKOUT1 Clock Source Selection
Set and reset by software.
000: No clock selected
001: Internal 28 MHz RC Oscillator clock selected
010: Internal 40KHz RC Oscillator clock selected
011: Low Speed Crystal Oscillator clock selected
100: System clock selected
101: Internal 8 MHz RC Oscillator clock selected
110: High Speed Crystal Oscillator clock selected
111: (CK_PLL / 2) or CK_PLL selected depend on PLLDV
4.3.16. Additional enable register (RCU_ADDEN)
Address offset: 0xF8
Reset value: 0x0000 0000
This register can be accessed by byte(8-bit), half-word(16-bit) and word(32-bit)
GD32F1x0 User Manual
98
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
I2C2EN
rw
Bits
Fields
Descriptions
31:1
Reserved
Must be kept at reset value
0
I2C2EN
I2C2 unit clock enable
This bit is set and reset by software
0: Disable I2C2 unit clock
1: Enable I2C2 unit clock
4.3.17. Additional reset register (RCU_ADDRST)
Address offset: 0xFC
Reset value: 0x0000 0000
This register can be accessed by byte(8-bit), half-word(16-bit) and word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
I2C2RST
rw
Bits
Fields
Descriptions
31:1
Reserved
Must be kept at reset value
0
I2C2RST
I2C2 unit reset
This bit is set and reset by software
0: Not reset I2C2 unit
1: Reset I2C2 unit
4.3.18. Voltage key register (RCU_VKEY)
Address offset: 0x100
Reset value: 0x0000 0000.
This register can be accessed by byte(8-bit), half-word(16-bit) and word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
KEY[31:16]
GD32F1x0 User Manual
99
w
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
KEY[15:0]
w
Bits
Fields
Descriptions
31:0
KEY[31:0]
The key of RCU_PDVSEL and RCU_DSV register
These bits are written only by software and read as 0. Only after write
0x1A2B3C4D to the RCU_VKEY, the RCU_PDVSEL and RCU_DSV register can
be written.
4.3.19. Deep-sleep mode voltage register (RCU_DSV)
For GD32F130xx and GD32F150xx devices
Offset: 0x134
Reset value: 0x0000 0000
This register can be accessed by byte(8-bit), half-word(16-bit) and word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
DSLPVS[2:0]
rw
Bits
Fields
Descriptions
31:3
Reserved
Must be kept at reset value
2:0
DSLPVS[2:0]
Deep-sleep mode voltage select
These bits is set and reset by software
000 : The core voltage is 1.2V in Deep-sleep mode
001 : The core voltage is 1.1V in Deep-sleep mode
010 : The core voltage is 1.0V in Deep-sleep mode
011 : The core voltage is 0.9V in Deep-sleep mode
100~111 : Reserved
For GD32F170xx and GD32F190xx devices
Address offset: 0x134
Reset value: 0x0000 0000.
This register can be accessed by byte(8-bit), half-word(16-bit) and word(32-bit)
GD32F1x0 User Manual
100
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
DSLPVS[2:0]
rw
Bits
Fields
Descriptions
31:3
Reserved
Must be kept at reset value
2:0
DSLPVS[2:0]
Deep-sleep mode voltage select
These bits is set and reset by software
000 : The core voltage is 1.8V in Deep-sleep mode
001 : The core voltage is 1.6V in Deep-sleep mode
010 : The core voltage is 1.4V in Deep-sleep mode
011 : The core voltage is 1.2V in Deep-sleep mode
100~111 : Reserved
4.3.20. Power down voltage select register (RCU_PDVSEL) of GD32F130xx and
GD32F150xx devices
Address offset: 0x138
Reset value: 0x0000 0000.
This register can be accessed by byte(8-bit), half-word(16-bit) and word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
PDRVS
rw
Bits
Fields
Descriptions
31:1
Reserved
Must be kept at reset value
0
PDRVS
Power down voltage select
This bit is set and reset by software
0: The Power down voltage is 2.6V
1: The Power down voltage is 1.8V
GD32F1x0 User Manual
101
5. General-purpose and alternate-function I/Os (GPIO
and AFIOs)
5.1. Introduction
There are up to 55 general purpose I/O pins, (GPIO), named PA0 ~ PA15 and PB0 ~ PB15,
PC0 ~ PC15, PD2, PF0/PF1, PF4 ~ PF7 for the device to implement logic input/output
functions. Each GPIO port has related control and configuration registers to satisfy the
requirements of specific applications.
The GPIO ports are pin-shared with other alternative functions (AFs) to obtain maximum
flexibility on the package pins. The GPIO pins can be used as alternative functional pins by
configuring the corresponding registers regardless of the AF input or output pins.
Each of the GPIO pins can be configured by software as output (push-pull or open-drain), as
input, as peripheral alternate function or as analog mode. Each GPIO pin can be configured
as pull-up, pull-down or no pull-up/pull-down. All GPIOs are high-current capable except for
analog mode.
5.2. Main features
Input/output direction control
Schmitt Trigger Input function enable control
Each pin weak pull-up/pull-down function
Output push-pull/open drain enable control
Output set/reset control
Output drive speed selection
Analog input/output configurations
Alternate function input/output configurations
Port configuration lock
For GD32F170xx and GD32F190xx devices, additional features are shown below.
Single cycle toggle output capability
5.3. Function description
Each of the general-purpose I/O ports can be configured as GPIO inputs, GPIO outputs, AF
function or analog mode by GPIO 32-bit configuration registers (GPIOx_CTL). AFIO input or
output is selected by AFIO output enable. When the port is output (GPIO output or AFIO
output), it can be configured as push-pull or open drain mode by GPIO output mode registers
(GPIOx_OMODE). And the port max speed can be configured by GPIO output speed
GD32F1x0 User Manual
102
registers (GPIOx_OSPD). Each port can be configured as floating (no pull-up and pull-down) ,
pull-up or pull-down function by GPIO pull-up/pull-down registers (GPIOx_PUD).
Table 5-1. GPIO configuration table
PAD TYPE
CTLn
OMn
PUDn
GPIO
INPUT
X
Floating
00
X
00
Pull-up
01
Pull-down
10
GPIO
OUTPUT
Push-pull
Floating
01
0
00
Pull-up
01
Pull-down
10
Open-drain
Floating
1
00
Pull-up
01
Pull-down
10
AFIO
INPUT
X
Floating
10
X
00
Pull-up
01
Pull-down
10
AFIO
OUTPUT
Push-pull
Floating
10
0
00
Pull-up
01
Pull-down
10
Open-drain
Floating
1
00
Pull-up
01
Pull-down
10
ANALOG
X
X
11
X
XX
Figure below shows the basic structure of an I/O Port bit.
Figure 5-1. Basic structure of a standard I/O port bit
Vdd
Vss
Vss
Vss
Output
Control
Vdd
Vdd
Output
Data
Registe
r
Input
Data
Register
Write
Read/Write
Alternate Function Output
Read
Alternate Function Input
Analog Input
Input driver
Output driver
I/O pin
Schmitt
trigger
Bit Set/Clear
Registers
GD32F1x0 User Manual
103
5.3.1. GPIO pin configuration
During or just after the reset period, the alternative functions are all inactive and the GPIO
ports are configured into the input floating mode that input disabled without Pull-Up(PU)/Pull-
Down(PD) resistors. But the Serial-Wired Debug pins are in input PU/PD mode after reset:
PA14: SWCLK in input pull-down mode
PA13: SWDIO in input pull-up mode
The GPIO pins can be configured as inputs or outputs. And all GPIO pins have an internal
weak pull-up and weak pull-down which can be chosen. When the GPIO pins are configured
as input pins, the data on the external pads can be captured at every AHB2 clock cycle to the
port input status register (GPIO_ISTAT).
When the GPIO pins are configured as output pins, user can configure the speed of the ports.
And chooses the output driver mode: Push-Pull or Open-Drain mode. The value of the port
output control register (GPIO_OCTL) is output on the I/O pin.
When programming the GPIO_OCTL at bit level no need to disable interrupts, user can
modify only one or several bits in a single atomic AHB2 write access by programming ‘1’ to
the Bit Operate Register (GPIO_BOP, or for clearing only GPIO_BC , or for toggle only
GPIO_TG). The other bits will not be affected.
5.3.2. Alternate functions (AF)
When the port is configured as AFIO (set CTLn to “10” bits, which is in GPIOx_CTL registers),
the port is used as peripheral alternate functions. Each port has sixteen alternate functions
can be configured by GPIO alternate functions select registers (GPIOx_AFSEL[1:0]). The
detail alternate function assignments for each port are in the device datasheet.
5.3.3. Additional functions
Some pins have additional functions, which have priority over the configuration in the standard
GPIO registers. When for ADC or DAC additional functions, the port must be configured as
analog mode. When for RTC, WKUPx and oscillators additional functions, the port type is set
automatically by related RTC, PMU and RCU registers. These ports can be used as normal
GPIO when the additional functions disabled.
5.3.4. Input configuration
When GPIO pin is configured as Input:
The Schmitt Trigger Input is activated
The weak pull-up and pull-down resistors could be chosen
Every AHB2 clock cycle the data present on the I/O pad is got to the Data Input
Register
The Output Buffer is disabled
GD32F1x0 User Manual
104
The figure below shows the Configuration of the I/O Port bit.
Figure 5-2. Input floating/pull up/pull down configurations
Vss
Vss
Vdd
Vdd
Input
Data
Register
Read
Input driver
I/O pin
Schmitt trigger
5.3.5. Output configuration
When GPIO pin is configured as output:
The Schmitt Trigger Input is activated.
The weak pull-up and pull-down resistors could be chosen.
The Output Buffer is enabled:
– Open Drain Mode: A “0” in the Output register activates the N-MOS while a “1” in
the Output register leaves the port in Hi-Z.
– Push-Pull Mode: A “0” in the Output register activates the N-MOS while a “1” in
theOutput register activates the P-MOS.
A read access to the Data Output register gets the last written value in Push-Pull mode
A read access to the Data Input Register gets the I/O state in open drain mode
The figure below shows the Output configuration of the I/O port bit.
Figure 5-3. Output configuration
Vdd
Vss
Vss
Output
Control
Vdd
Output
Data
Registe
r
Input
Data
Regist
er
Write
Read/Write
Read
Input driver
Output driver
I/O pin
Schmitt trigger
Bit Set/Clear
Registers
Vss
Vdd
GD32F1x0 User Manual
105
5.3.6. Analog configuration
When GPIO pin is used as analog configuration:
The weak pull-up and pull-down resistors are disabled.
The Output Buffer is disabled.
The Schmitt Trigger Input is de-activated.
Read access to the Data Input Register gets the value “0”.
The figure below shows the high impedance-analog configuration
Figure 5-4. High impedance-analog configuration
Vss
Vss
Vdd /
Vdd_FT
Vdd
Input Data
Register
Read
Analog Input
Input driver
I/O pin
Schmitt
trigger
off
5.3.7. Alternate function (AF) configuration
To suit for different device packages, the GPIO supports some alternate functions to some
other pins by software.
When be configured as Alternate Function:
The Output Buffer is turned on in Open Drain or Push-Pull configuration
The Output Buffer is driven by the peripheral
The Schmitt Trigger Input is activated
The weak pull-up and pull-down resistors could be chosen.
The data present on the I/O pin is sampled into the Data Input Register every AHB2 clock
cycle
A read access to the Data Input Register gets the I/O state in open drain mode
A read access to the Data Output register gets the last written value in Push-Pull mode
The figure below shows the Alternate Function Configuration of the I/O Port bit.
GD32F1x0 User Manual
106
Figure 5-5. Alternate function configuration
Vdd
Vss
Vss
Output
Control
Vdd
Input
Data
Regist
er
Alternate Function Output
Read
Alternate Function Input
Input driver
Output driver
I/O pin
Schmitt trigger
Vss
Vdd
5.3.8. GPIO locking function
The locking mechanism allows the IO configuration to be protected.
The protected registers are GPIOx_CTL, GPIOx_OMODE, GPIOx_OSPD, GPIOx_PUD,
GPIOx_AFSEL[1:0]. It allows the I/O configuration to be frozen by the 32-bit locking register
(GPIOx_LOCK). When the LOCK sequence has been applied on a port bit, it is no longer
able to modify the value of the port bit until the next reset. It should be recommended to be
used in the configuration of driving a power module.
5.4. GPIO registers
5.4.1. Port control register (GPIOx_CTL) (x=A..D,F)
Address offset: 0x00
Reset value: 0x2800 0000 for port A; 0x0000 0000 for others.
This register can be accessed by byte(8-bit), half-word(16-bit) and word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
CTL15[1:0]
CTL14[1:0]
CTL13[1:0]
CTL12[1:0]
CTL11[1:0]
CTL10[1:0]
CTL9[1:0]
CTL8[1:0]
rw
rw
rw
rw
rw
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
CTL7[1:0]
CTL6[1:0]
CTL5[1:0]
CTL4[1:0]
CTL3[1:0]
CTL2[1:0]
CTL1[1:0]
CTL0[1:0]
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31:30
CTL15[1:0]
Pin 15 configuration bits
These bits are set and cleared by software.
Refer to CTL0[1:0] description
GD32F1x0 User Manual
107
29:28
CTL14[1:0]
Pin 14 configuration bits
These bits are set and cleared by software.
Refer to CTL0[1:0] description
27:26
CTL13[1:0]
Pin 13 configuration bits
These bits are set and cleared by software.
Refer to CTL0[1:0] description
25:24
CTL12[1:0]
Pin 12 configuration bits
These bits are set and cleared by software.
Refer to CTL0[1:0] description
23:22
CTL11[1:0]
Pin 11 configuration bits
These bits are set and cleared by software.
Refer to CTL0[1:0] description
21:20
CTL10[1:0]
Pin 10 configuration bits
These bits are set and cleared by software.
Refer to CTL0[1:0] description
19:18
CTL9[1:0]
Pin 9 configuration bits
These bits are set and cleared by software.
Refer to CTL0[1:0] description
17:16
CTL8[1:0]
Pin 8 configuration bits
These bits are set and cleared by software.
Refer to CTL0[1:0] description
15:14
CTL7[1:0]
Pin 7 configuration bits
These bits are set and cleared by software.
Refer to CTL0[1:0] description
13:12
CTL6[1:0]
Pin 6 configuration bits
These bits are set and cleared by software.
Refer to CTL0[1:0] description
11:10
CTL5[1:0]
Pin 5 configuration bits
These bits are set and cleared by software.
Refer to CTL0[1:0] description
9:8
CTL4[1:0]
Pin 4 configuration bits
These bits are set and cleared by software.
Refer to CTL0[1:0] description
7:6
CTL3[1:0]
Pin 3 configuration bits
These bits are set and cleared by software.
Refer to CTL0[1:0] description
5:4
CTL2[1:0]
Pin 2 configuration bits
These bits are set and cleared by software.
GD32F1x0 User Manual
108
Refer to CTL0[1:0] description
3:2
CTL1[1:0]
Pin 1 configuration bits
These bits are set and cleared by software.
Refer to CTL0[1:0] description
1:0
CTL0[1:0]
Pin 0 configuration bits
These bits are set and cleared by software.
00: Input mode (reset state)
01: GPIO output mode
10: Alternate function mode.
11: Analog mode
5.4.2. Port output mode register (GPIOx_OMODE) (x=A..D,F)
Address offset: 0x04
Reset value: 0x0000 0000
This register can be accessed by byte(8-bit), half-word(16-bit) and word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
OM15
OM14
OM13
OM12
OM11
OM10
OM9
OM8
OM7
OM6
OM5
OM4
OM3
OM2
OM1
OM0
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31:16
Reserved
Must be kept at reset value
15
OM15
Pin 15 output mode bit
These bits are set and cleared by software.
Refer to OM0 description
14
OM14
Pin 14 output mode bit
These bits are set and cleared by software.
Refer to OM0 description
13
OM13
Pin 13 output mode bit
These bits are set and cleared by software.
Refer to OM0 description
12
OM12
Pin 12 output mode bit
These bits are set and cleared by software.
Refer to OM0 description
11
OM11
Pin 11 output mode bit
These bits are set and cleared by software.
GD32F1x0 User Manual
109
Refer to OM0 description
10
OM10
Pin 10 output mode bit
These bits are set and cleared by software.
Refer to OM0 description
9
OM9
Pin 9 output mode bit
These bits are set and cleared by software.
Refer to OM0 description
8
OM8
Pin 8 output mode bit
These bits are set and cleared by software.
Refer to OM0 description
7
OM7
Pin 7 output mode bit
These bits are set and cleared by software.
Refer to OM0 description
6
OM6
Pin 6 output mode bit
These bits are set and cleared by software.
Refer to OM0 description
5
OM5
Pin 5 output mode bit
These bits are set and cleared by software.
Refer to OM0 description
4
OM4
Pin 4 output mode bit
These bits are set and cleared by software.
Refer to OM0 description
3
OM3
Pin 3 output mode bit
These bits are set and cleared by software.
Refer to OM0 description
2
OM2
Pin 2 output mode bit
These bits are set and cleared by software.
Refer to OM0 description
1
OM1
Pin 1 output mode bit
These bits are set and cleared by software.
Refer to OM0 description
0
OM0
Pin 0 output mode bit
These bits are set and cleared by software.
0: Output push-pull mode (reset)
1: Output open-drain mode
GD32F1x0 User Manual
110
5.4.3. Port output speed register (GPIOx_OSPD) (x=A..D,F)
Address offset: 0x08
Reset value: 0x0C00 0000 for port A; 0x0000 0000 for others.
This register can be accessed by byte(8-bit), half-word(16-bit) and word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
OSPD15[1:0]
OSPD14[1:0]
OSPD13[1:0]
OSPD12[1:0]
OSPD11[1:0]
OSPD10[1:0]
OSPD9[1:0]
OSPD8[1:0]
rw
rw
rw
rw
rw
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
OSPD7[1:0]
OSPD6[1:0]
OSPD5[1:0]
OSPD4[1:0]
OSPD3[1:0]
OSPD2[1:0]
OSPD1[1:0]
OSPD0[1:0]
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31:30
OSPD15[1:0]
Pin 15 output max speed bits
These bits are set and cleared by software.
Refer to OSPD0[1:0] description
29:28
OSPD14[1:0]
Pin 14 output max speed bits
These bits are set and cleared by software.
Refer to OSPD0[1:0] description
27:26
OSPD13[1:0]
Pin 13 output max speed bits
These bits are set and cleared by software.
Refer to OSPD0[1:0 ]description
25:24
OSPD12[1:0]
Pin 12 output max speed bits
These bits are set and cleared by software.
Refer to OSPD0[1:0] description
23:22
OSPD11[1:0]
Pin 11 output max speed bits
These bits are set and cleared by software.
Refer to OSPD0[1:0] description
21:20
OSPD10[1:0]
Pin 10 output max speed bits
These bits are set and cleared by software.
Refer to OSPD0[1:0] description
19:18
OSPD9[1:0]
Pin 9 output max speed bits
These bits are set and cleared by software.
Refer to OSPD0[1:0] description
17:16
OSPD8[1:0]
Pin 8 output max speed bits
These bits are set and cleared by software.
Refer to OSPD0[1:0] description
15:14
OSPD7[1:0]
Pin 7 output max speed bits
These bits are set and cleared by software.
GD32F1x0 User Manual
111
Refer to OSPD0[1:0] description
13:12
OSPD6[1:0]
Pin 6 output max speed bits
These bits are set and cleared by software.
Refer to OSPD0[1:0] description
11:10
OSPD5[1:0]
Pin 5 output max speed bits
These bits are set and cleared by software.
Refer to OSPD0[1:0] description
9:8
OSPD4[1:0]
Pin 4 output max speed bits
These bits are set and cleared by software.
Refer to OSPD0[1:0] description
7:6
OSPD3[1:0]
Pin 3 output max speed bits
These bits are set and cleared by software.
Refer to OSPD0[1:0] description
5:4
OSPD2[1:0]
Pin 2 output max speed bits
These bits are set and cleared by software.
Refer to OSPD0[1:0] description
3:2
OSPD1[1:0]
Pin 1 output max speed bits
These bits are set and cleared by software.
Refer to OSPD0[1:0] description
1:0
OSPD0[1:0]
Pin 0 output max speed bits
These bits are set and cleared by software.
x0: Output max speed 2M (reset state)
01: Output max speed 10M
11: Output max speed 50M
5.4.4. Port pull-up/down register (GPIOx_PUD) (x=A..D,F)
Address offset: 0x0C
Reset value: 0x2400 0000 for port A; 0x0000 0000 for others.
This register can be accessed by byte(8-bit), half-word(16-bit) and word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
PUD15[1:0]
PUD14[1:0]
PUD13[1:0]
PUD12[1:0]
PUD11[1:0]
PUD10[1:0]
PUD9[1:0]
PUD8[1:0]
rw
rw
rw
rw
rw
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
PUD7[1:0]
PUD6[1:0]
PUD5[1:0]
PUD4[1:0]
PUD3[1:0]
PUD2[1:0]
PUD1[1:0]
PUD0[1:0]
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31:30
PUD15[1:0]
Pin 15 pull-up or pull-down bits
GD32F1x0 User Manual
112
These bits are set and cleared by software.
Refer to PUD0[1:0] description
29:28
PUD14[1:0]
Pin 14 pull-up or pull-down bits
These bits are set and cleared by software.
Refer to PUD0[1:0] description
27:26
PUD13[1:0]
Pin 13 pull-up or pull-down bits
These bits are set and cleared by software.
Refer to PUD0[1:0] description
25:24
PUD12[1:0]
Pin 12 pull-up or pull-down bits
These bits are set and cleared by software.
Refer to PUD0[1:0] description
23:22
PUD11[1:0]
Pin 11 pull-up or pull-down bits
These bits are set and cleared by software.
Refer to PUD0[1:0] description
21:20
PUD10[1:0]
Pin 10 pull-up or pull-down bits
These bits are set and cleared by software.
Refer to PUD0[1:0] description
19:18
PUD9[1:0]
Pin 9 pull-up or pull-down bits
These bits are set and cleared by software.
Refer to PUD0[1:0] description
17:16
PUD8[1:0]
Pin 8 pull-up or pull-down bits
These bits are set and cleared by software.
Refer to PUD0[1:0] description
15:14
PUD7[1:0]
Pin 7 pull-up or pull-down bits
These bits are set and cleared by software.
Refer to PUD0[1:0] description
13:12
PUD6[1:0]
Pin 6 pull-up or pull-down bits
These bits are set and cleared by software.
Refer to PUD0[1:0] description
11:10
PUD5[1:0]
Pin 5 pull-up or pull-down bits
These bits are set and cleared by software.
Refer to PUD0[1:0] description
9:8
PUD4[1:0]
Pin 4 pull-up or pull-down bits
These bits are set and cleared by software.
Refer to PUD0[1:0] description
7:6
PUD3[1:0]
Pin 3 pull-up or pull-down bits
These bits are set and cleared by software.
GD32F1x0 User Manual
113
Refer to PUD0[1:0] description
5:4
PUD2[1:0]
Pin 2 pull-up or pull-down bits
These bits are set and cleared by software.
Refer to PUD0[1:0] description
3:2
PUD1[1:0]
Pin 1 pull-up or pull-down bits
These bits are set and cleared by software.
Refer to PUD0[1:0] description
1:0
PUD0[1:0]
Pin 0 pull-up or pull-down bits
These bits are set and cleared by software.
00: Floating mode, no pull-up and pull-down (reset state)
01: With pull-up mode
10: With pull-down mode
11: Reserved
5.4.5. Port input status register (GPIOx_ISTAT) (x=A..D,F)
Address offset: 0x10
eset value: 0x0000 XXXX.
This register can be accessed by byte(8-bit), half-word(16-bit) and word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
ISTA
T15
ISTA
T14
ISTA
T13
ISTA
T12
ISTA
T11
ISTA
T10
ISTA
T 9
ISTA
T 8
ISTA
T 7
ISTA
T 6
ISTA
T 5
ISTA
T 4
ISTA
T 3
ISTA
T 2
ISTA
T 1
ISTA
T 0
r
r
r
r
r
r
r
r
r
r
r
r
r
r
r
r
Bits
Fields
Descriptions
31:16
Reserved
Must be kept at reset value
15:0
ISTAT[15:0]
Port input data
These bits are set and cleared by hardware.
0: Input signal low
1: Input signal high
5.4.6. Port output control register (GPIOx_OCTL) (x=A..D,F)
Address offset: 0x14
Reset value: 0x0000 0000
This register can be accessed by byte(8-bit), half-word(16-bit) and word(32-bit)
GD32F1x0 User Manual
114
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
OCTL15
OCTL14
OCTL13
OCTL12
OCTL11
OCTL10
OCTL9
OCTL8
OCTL7
OCTL6
OCTL5
OCTL4
OCTL3
OCTL2
OCTL1
OCTL0
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31:16
Reserved
Must be kept at reset value
15:0
OCTL[15:0]
Port output data
These bits are set and cleared by software.
0: Pin output low
1: Pin output high
5.4.7. Port bit operate register (GPIOx_BOP) (x=A..D,F)
Address offset: 0x18
Reset value: 0x0000 0000
This register can be accessed by byte(8-bit), half-word(16-bit) and word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
CR15
CR14
CR13
CR12
CR11
CR10
CR9
CR8
CR7
CR6
CR5
CR4
CR3
CR2
CR1
CR0
w
w
w
w
w
w
w
w
w
w
w
w
w
w
w
w
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
BOP15
BOP14
BOP13
BOP12
BOP11
BOP10
BOP9
BOP8
BOP7
BOP6
BOP5
BOP4
BOP3
BOP2
BOP1
BOP0
w
w
w
w
w
w
w
w
w
w
w
w
w
w
w
w
Bits
Fields
Descriptions
31:16
CRx
Port Clear bit
These bits are set and cleared by software.
0: No action on the corresponding OCTLx bit
1: Clear the corresponding OCTLx bit
15:0
BOPx[15:0]
Port Set bit
These bits are set and cleared by software.
0: No action on the corresponding OCTLx bit
1: Set the corresponding OCTLx bit
5.4.8. Port configuration lock register (GPIOx_LOCK) (x=A, B)
Address offset: 0x1C
Reset value: 0x0000 0000
GD32F1x0 User Manual
115
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
LKK
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
LK15
LK14
LK13
LK12
LK11
LK10
LK9
LK8
LK7
LK6
LK5
LK4
LK3
LK2
LK1
LK0
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31:17
Reserved
Must be kept at reset value
16
LKK
Lock key
It can only be setted using the Lock Key Writing Sequence.And can always
be read.
0: Port configuration lock key not active
1: Port configuration lock key active.
GPIO_LOCK register is locked until an MCU reset..
LOCK key writing sequence
Write 1→Write 0→Write 1→ Read 0→ Read 1
Note: The value of LKx[15:0] must hold during the LOCK Key Writing
sequence.
15:0
LKx[15:0]
Port Lock bit 0 ~ 15
These bits are set and cleared by software
0: Port configuration not locked
1: Port configuration locked
5.4.9. Alternate function selected register0 (GPIOx_AFSEL0) (x=A, B, C)
Address offset: 0x20
Reset value: 0x0000 0000
This register can be accessed by byte(8-bit), half-word(16-bit) and word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
SEL7[3:0]
SEL6[3:0]
SEL5[3:0]
SEL4[3:0]
rw
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
SEL3[3:0]
SEL2[3:0]
SEL1[3:0]
SEL0[3:0]
rw
rw
rw
rw
Bits
Fields
Descriptions
31:28
SEL7[3:0]
Pin 7 alternate function selected
These bits are set and cleared by software.
GD32F1x0 User Manual
116
Refer to SEL0[3:0] description
27:24
SEL6[3:0]
Pin 6 alternate function selected
These bits are set and cleared by software.
Refer to SEL0[3:0] description
23:20
SEL5[3:0]
Pin 5 alternate function selected
These bits are set and cleared by software.
Refer to SEL0[3:0] description
19:16
SEL4[3:0]
Pin 4 alternate function selected
These bits are set and cleared by software.
Refer to SEL0[3:0] description
15:12
SEL3[3:0]
Pin 3 alternate function selected
These bits are set and cleared by software.
Refer to SEL0[3:0] description
11:8
SEL2[3:0]
Pin 2 alternate function selected
These bits are set and cleared by software.
Refer to SEL0[3:0] description
7:4
SEL1[3:0]
Pin 1 alternate function selected
These bits are set and cleared by software.
Refer to SEL0[3:0] description
3:0
SEL0[3:0]
Pin 0 alternate function selected
These bits are set and cleared by software.
0000: AF0 selected (reset value)
0001: AF1 selected
0010: AF2 selected
0011: AF3 selected
0100: AF4 selected (Port A,B only)
0101: AF5 selected (Port A,B only)
0110: AF6 selected (Port A,B only)
0111: AF7 selected (Port A,B only)
1000 ~ 1111: Reserved
5.4.10. Alternate function selected register1 (GPIOx_AFSEL1) (x=A,B,C)
Address offset: 0x24
Reset value: 0x0000 0000
This register can be accessed by byte(8-bit), half-word(16-bit) and word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
SEL15[3:0]
SEL14[3:0]
SEL13[3:0]
SEL12[3:0]
GD32F1x0 User Manual
117
rw
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
SEL11[3:0]
SEL10[3:0]
SEL9[3:0]
SEL8[3:0]
rw
rw
rw
rw
Bits
Fields
Descriptions
31:28
SEL15[3:0]
Pin 15 alternate function selected
These bits are set and cleared by software.
Refer to SEL8[3:0] description
27:24
SEL14[3:0]
Pin 14 alternate function selected
These bits are set and cleared by software.
Refer to SEL8[3:0] description
23:20
SEL13[3:0]
Pin 13 alternate function selected
These bits are set and cleared by software.
Refer to SEL8[3:0] description
19:16
SEL12[3:0]
Pin 12 alternate function selected
These bits are set and cleared by software.
Refer to SEL8[3:0] description
15:12
SEL11[3:0]
Pin 1 alternate function selected
These bits are set and cleared by software.
Refer to SEL8[3:0] description
11:8
SEL10[3:0]
Pin 10 alternate function selected
These bits are set and cleared by software.
Refer to SEL8[3:0] description
7:4
SEL9[3:0]
Pin 9 alternate function selected
These bits are set and cleared by software.
Refer to SEL8[3:0] description
3:0
SEL8[3:0]
Pin 8 alternate function selected
These bits are set and cleared by software.
0000: AF0 selected (reset value)
0001: AF1 selected
0010: AF2 selected
0011: AF3 selected
0100: AF4 selected (Port A,B only)
0101: AF5 selected (Port A,B only)
0110: AF6 selected (Port A,B only)
0111: AF7 selected (Port A,B only)
1000 ~ 1111: Reserved
GD32F1x0 User Manual
118
5.4.11. Bit clear register (GPIOx_BC) (x=A..D,F)
Address offset: 0x28
Reset value: 0x0000 0000
This register can be accessed by byte(8-bit), half-word(16-bit) and word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
CR15
CR14
CR13
CR12
CR11
CR10
CR9
CR8
CR7
CR6
CR5
CR4
CR3
CR2
CR1
CR0
w
w
w
w
w
w
w
w
w
w
w
w
w
w
w
w
Bits
Fields
Descriptions
31:16
Reserved
Must be kept at reset value
15:0
CRx[15:0]
Port Clear bit
These bits are set and cleared by software.
0: No action on the corresponding OCTLx bit
1: Clear the corresponding OCTLx bit
5.4.12. Port bit toggle register (GPIOx_TGx) (x=A..D,F) of GD32F170xx and
GD32F190xx devices
Address offset: 0x2C
Reset value: 0x0000 0000
This register can be accessed by byte(8-bit), half-word(16-bit) and word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
TG15
TG14
TG13
TG12
TG11
TG10
TG9
TG8
TG7
TG6
TG5
TG4
TG3
TG2
TG1
TG0
w
w
w
w
w
w
w
w
w
w
w
w
w
w
w
w
Bits
Fields
Descriptions
31:16
Reserved
Must be kept at reset value
15:0
TGx[15:0]
Port Toggle bit
These bits are set and cleared by software.
0: No action on the corresponding OCTLx bit
1: Toggle the corresponding OCTLx bit
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6. CRC calculation unit
6.1. Introduction
A cyclic redundancy check (CRC) is an error-detecting code commonly used in digital
networks and storage devices to detect accidental changes to raw data.
This CRC calculation unit can be used to calculate 32/16/8 bit CRC code within fixed
polynomial.
6.2. Main features
32/16/8 bit data input and 32-bit data output. Calculation period is 4/2/1 AHB Clock
cycles for 32/16/8 bit input data size from data entered to the calculation result vailable.
Free 8-bit register is unrelated for calculation and can be used for any other goals by
any other peripheral devices.
Fixed polynomial: 0x4C11DB7
X32 + X26 + X23 + X22 + X16 + X12 + X11 + X10 +X8 + X7 + X5 + X4 + X2+ X + 1
This 32-bit CRC polynomial is a common polynomial used in Ethernet.
One 32-bit Input buffer for higher bus efficiency
Reversible option for input and output data
User setting initial value for flexible calculation
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Figure 6-1.Block Diagram of CRC Calculation Unit
AHB
BUS
Interface
Input Data Register
Reversible Option
Output Data Register (32 bit)
Reversible Option
Free Purpose 8 bit Register
Data Input
Reversible
Option
Data Output
Reversible Option
CRC Calculation Unit
Fixed polynomial
0x4C11DB7
Data Access
6.3. Function description
There are five functions in this unit:
CRC calculation unit is used to calculate the 32-bit raw data, and CRC_DATA register
will receive the raw data and store the calculation result. If do not clear the CRC_DATA
register by software setting CRC_CTL register, the new input raw data will calculate
based on the result of previous value of CRC_DATA.
CRC calculation will spend 4/2/1 AHB clock cycles for 32/16/8 bit data size, during this
period AHB will not be hanged because the existence of the 32-bit input buffer.
This module supplies an 8-bit free register CRC_FDATA.
CRC_FDATA is unrelated to the CRC calculation, any value you write in will be read
out at anytime.
Reversible function can reverse the input data and output data.
For input data, 3 reverse types can be selected.
Original data is 0x1A2B3C4D:
1) byte reverse:
32-bit data is divided into 4 groups and reverse implement in group inside. Reversed
data: 0x58D43CB2.
2) half-word reverse:
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32-bit data is divided in to 2 groups and reverse implement in group
inside. Reversed data: 0xD458B23C.
3) word reverse:
32-bit data is divided in to 1 group and reverse implement in group inside. Reversed
data: 0xB23CD458
For output data, reverse type is word reverse.
For example: when REV_O=1, calculation result 0x22CC4488 will be
converted to 0x11223344.
Multiple input data size support function will make users have the flexibility to
adjust the combination of the calculation data.
For example: 6 bytes input data can be combined by 1 word and 1 half-word,
also it can be combined by 3 half-word.
User configurable initial calculation data function will support user calculate
CRC data value under any initial value.
6.4. CRC Registers
6.4.1. Data Register (CRC_DATA)
Address offset: 0x00
Reset value: 0xFFFF FFFF
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
DATA[31:16]
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
DATA[15:0]
rw
Bits
Fields
Descriptions
31:0
DATA[31:0]
CRC calculation result bits
Software writes and reads.
This register is used to calculate new data, and the register can be written the new
data directly.Write value cannot be read because the read value is the CRC
calculation result. If the input calculation data is less than 4 byte, the actual valid
byte is the corresponding least significant byte.
6.4.2. Free Data Register (CRC_FDATA)
Address offset: 0x04
Reset value: 0x0000 0000
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This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
FDATA[7:0]
rw
Bits
Fields
Descriptions
31:8
Reserved
Must be kept at reset value
7:0
FDATA[7:0]
Free Data Register Bits
Software write and read.
These bits are unrelated with CRC calculation. This byte can be used for any goals
by any other peripheral. The CRC_CTL register will generate no effect to the byte.
6.4.3. Control Register (CRC_CTL)
Address offset: 0x08
Reset value: 0x0000 0000
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
REV_O
REV_I[1:0]
Reserved
RST
rw
rw
rs
Bits
Fields
Descriptions
31:8
Reserved
Must be kept at reset value
7
REV_O
Output Data Reverse Function
0: Output data not reverse
1: Output data reversed by 32-bit
6:5
REV_I[1:0]
Input Data Reverse Function
0x0: Input data not reverse
0x1: Input data reversed by byte type
0x2: Input data reversed by half-word type
0x3: Input data reversed by word type
4:1
Reserved
Must be kept at reset value
0
RST
This bit can reset the CRC_DATA register to the value of 0xFFFFFFFF then
GD32F1x0 User Manual
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automatically cleared itself to 0 by hardware. This bit will generate no effect to
CRC_FDATA.
Software writes and reads.
6.4.4. Initialization Data Register (CRC_IDATA)
Address offset: 0x10
Reset value: 0xFFFF FFFF
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
IDATA [31:16]
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
IDATA [15:0]
rw
Bits
Fields
Descriptions
31:0
IDATA[31:0]
Configurable initial CRC data value
When RST bit in CRC_CTL asserted, CRC_DATA will be programmed to this value
.
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7. Interrupts and events
7.1. Introduction
Cortex-M3 integrates the Nested Vectored Interrupt Controller (NVIC) for efficient exception
and interrupts processing. NVIC facilitates low-latency exception and interrupt handling and
controls power management. It’s tightly coupled to the processor core. You can read the
Technical Reference Manual of Cortex-M3 for more details about NVIC.
An external interrupt/event controller (EXTI) is provided in chip which contains 23 independent
edge detectors and generates interrupt requests or events to the processor. The EXTI has
three trigger types: rising edge, falling edge and both edges. Each edge detector in the EXTI
can be configured and masked independently.
7.2. Main features
Cortex-M3 system exception
Up to 52 maskable peripheral interrupts for GD32F130xx and GD32F150xx devices or
74 maskable peripheral interrupts for GD32F170xx and GD32F190xx devices
4 bits interrupt priority configuration-16 priority levels
Efficient interrupt processing
Support exception pre-emption and tail-chaining
Wake up system from power saving mode
Up to 23 independent edge detectors in EXTI
3 trigger types: rising, falling and both edges
Software interrupt or event trigger
Trigger sources configurable
7.3. Function description
7.3.1. NVIC and exception/interrupt processing
The ARM Cortex-M3 processor and the Nested Vectored Interrupt Controller (NVIC) prioritize
and handle all exceptions in Handler Mode. The processor state is automatically stored to the
stack on an exception and automatically restored from the stack at the end of the Interrupt
Service Routine (ISR).
The vector is fetched in parallel to the state saving, enabling efficient interrupt entry. The
processor supports tail-chaining, which enables back-to-back interrupts to be performed
without the overhead of state saving and restoration.
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Table 7-1. NVIC exception types in Cotrex-M3
Exception
Type
Vector
Number
Priority (a)
Vector Address
Description
-
0
-
0x0000_0000
Reserved
Reset
1
-3
0x0000_0004
Reset
NMI
2
-2
0x0000_0008
Non maskable interrupt.
HardFault
3
-1
0x0000_000C
All class of fault
MemManage
4
Programmable
0x0000_0010
Memory management
BusFault
5
Programmable
0x0000_0014
Prefetch fault, memory
access fault
UsageFault
6
Programmable
0x0000_0018
Undefined instruction or
illegal state
-
7-10
-
0x0000_001C -
0x0000_002B
Reserved
SVCall
11
Programmable
0x0000_002C
System service call via SWI
instruction
Debug
Monitor
12
Programmable
0x0000_0030
Debug Monitor
-
13
-
0x0000_0034
Reserved
PendSV
14
Programmable
0x0000_0038
Pendable request for system
service
SysTick
15
Programmable
0x0000_003C
System tick timer(b)
Interrupts
16-89
Programmable
0x0000_0040 -
0x0000_0164
Peripheral Interrupts
(See below table for detail)
Table 7-2. Interrupt vector table of GD32F130xx and GD32F150xx devices
Interrupt
Number
Vector
Number
Peripheral Interrupt Description
Vector Address
IRQ 0
16
Window watchdog interrupt
0x0000_0040
IRQ 1
17
LVD through EXTI Line detection interrupt
0x0000_0044
IRQ 2
18
RTC global interrupt
0x0000_0048
IRQ 3
19
Flash global interrupt
0x0000_004C
IRQ 4
20
RCU global interrupt
0x0000_0050
IRQ 5
21
EXTI Line0-1 interrupt
0x0000_0054
IRQ 6
22
EXTI Line2-3 interrupt
0x0000_0058
IRQ 7
23
EXTI Line4-15 interrupt
0x0000_005C
IRQ 8
24
TSI global interrupt
0x0000_0060
IRQ 9
25
DMA Channel0 global interrupt
0x0000_0064
IRQ 10
26
DMA Channel1-2 global interrupt
0x0000_0068
IRQ 11
27
DMA Channel3-4 global interrupt
0x0000_006C
IRQ 12
28
ADC and CMP0-1 interrupt
0x0000_0070
IRQ 13
29
TIMER0 Break, update, trigger and
commutation interrupt
0x0000_0074
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Interrupt
Number
Vector
Number
Peripheral Interrupt Description
Vector Address
IRQ 14
30
TIMER0 Capture Compare interrupt
0x0000_0078
IRQ 15
31
TIMER1 global interrupt
0x0000_007C
IRQ 16
32
TIMER2 global interrupt
0x0000_0080
IRQ 17
33
TIMER5 and DAC global interrupt
0x0000_0084
IRQ 18
34
Reserved
0x0000_0088
IRQ 19
35
TIMER13 global interrupt
0x0000_008C
IRQ 20
36
TIMER14 global interrupt
0x0000_0090
IRQ 21
37
TIMER15 global interrupt
0x0000_0094
IRQ 22
38
TIMER16 global interrupt
0x0000_0098
IRQ 23
39
I2C0 event interrupt
0x0000_009C
IRQ 24
40
I2C1 event interrupt
0x0000_00A0
IRQ 25
41
SPI0 global interrupt
0x0000_00A4
IRQ 26
42
SPI1 global interrupt
0x0000_00A8
IRQ 27
43
USART0 global interrupt
0x0000_00AC
IRQ 28
44
USART1 global interrupt
0x0000_00B0
IRQ 29
45
Reserved
0x0000_00B4
IRQ 30
46
CEC global interrupt
0x0000_00B8
IRQ 31
47
Reserved
0x0000_00BC
IRQ 32
48
I2C0 error interrupt
0x0000_00C0
IRQ 33
49
Reserved
0x0000_00C4
IRQ 34
50
I2C1 error interrupt
0x0000_00C8
IRQ 35
51
I2C2 event interrupt
0x0000_00CC
IRQ 36
52
I2C2 error interrupt
0x0000_00D0
IRQ 37
53
USBD Low Priority interrupts
0x0000_00D4
IRQ 38
54
USBD High Priority interrupts
0x0000_00D8
IRQ 39-41
55-57
Reserved
0x0000_00DC-
0x0000_00E4
IRQ 42
58
USBD Wake Up through EXTI Line18 interrupt
0x0000_00E8
IRQ 43-47
59-63
Reserved
0x0000_00EC-
0x0000_00FC
IRQ 48
64
DMA Channel5-6 global interrupt
0x0000_0100
IRQ 49-50
65-66
Reserved
0x0000_0104-
0x0000_0108
IRQ 51
67
SPI2 global interrupt
0x0000_010C
Table 7-3. Interrupt vector table of GD32F170xx and GD32F190xx devices
Interrupt
Number
Vector
Number
Peripheral Interrupt Description
Vector Address
IRQ 0
16
Window watchdog timer interrupt
0x0000_0040
IRQ 1
17
LVD through EXTI Line detection interrupt
0x0000_0044
IRQ 2
18
RTC global interrupt
0x0000_0048
GD32F1x0 User Manual
127
Interrupt
Number
Vector
Number
Peripheral Interrupt Description
Vector Address
IRQ 3
19
Flash global interrupt
0x0000_004C
IRQ 4
20
RCU global interrupt
0x0000_0050
IRQ 5
21
EXTI Line0-1 interrupt
0x0000_0054
IRQ 6
22
EXTI Line2-3 interrupt
0x0000_0058
IRQ 7
23
EXTI Line4-15 interrupt
0x0000_005C
IRQ 8
24
TSI global interrupt
0x0000_0060
IRQ 9
25
DMA Channel0 global interrupt
0x0000_0064
IRQ 10
26
DMA Channel1-2 global interrupt
0x0000_0068
IRQ 11
27
DMA Channel3-4 global interrupt
0x0000_006C
IRQ 12
28
ADC and CMP0-1 interrupt
0x0000_0070
IRQ 13
29
TIMER0 Break, update, trigger and
commutation interrupt
0x0000_0074
IRQ 14
30
TIMER0 Capture Compare interrupt
0x0000_0078
IRQ 15
31
TIMER1 global interrupt
0x0000_007C
IRQ 16
32
TIMER2 global interrupt
0x0000_0080
IRQ 17
33
TIMER5 and DAC global interrupt
0x0000_0084
IRQ 18
34
Reserved
0x0000_0088
IRQ 19
35
TIMER13 global interrupt
0x0000_008C
IRQ 20
36
TIMER14 global interrupt
0x0000_0090
IRQ 21
37
TIMER15 global interrupt
0x0000_0094
IRQ 22
38
TIMER16 global interrupt
0x0000_0098
IRQ 23
39
I2C0 event interrupt
0x0000_009C
IRQ 24
40
I2C1 event interrupt
0x0000_00A0
IRQ 25
41
SPI0 global interrupt
0x0000_00A4
IRQ 26
42
SPI1 global interrupt
0x0000_00A8
IRQ 27
43
USART0 global interrupt
0x0000_00AC
IRQ 28
44
USART1 global interrupt
0x0000_00B0
IRQ 29
45
Reserved
0x0000_00B4
IRQ 30
46
CEC global interrupt
0x0000_00B8
IRQ 31
47
Reserved
0x0000_00BC
IRQ 32
48
I2C0 error interrupt
0x0000_00C0
IRQ 33
49
Reserved
0x0000_00C4
IRQ 34
50
I2C1 error interrupt
0x0000_00C8
IRQ 35
51
I2C2 event interrupt
0x0000_00CC
IRQ 36
52
I2C2 error interrupt
0x0000_00D0
IRQ 37-42
53-58
Reserved
0x0000_00D4-
0x0000_00E8
IRQ43
59
CAN0_TX
0x0000_00EC
IRQ44
60
CAN0_RX0
0x0000_00F0
IRQ45
61
CAN0_RX1
0x0000_00F4
GD32F1x0 User Manual
128
Interrupt
Number
Vector
Number
Peripheral Interrupt Description
Vector Address
IRQ46
62
CAN0_SCE
0x0000_00F8
IRQ 47
63
SLCD
0x0000_00FC
IRQ 48
64
DMA Channe5-6 global interrupt
0x0000_0100
IRQ 49-50
65-66
Reserved
0x0000_0104-
0x0000_0108
IRQ 51
67
SPI2 global interrupt
0x0000_010C
IRQ52-69
68-85
Reserved
0x0000_0110-
0x0000_0154
IRQ70
86
CAN1_TX
0x0000_0158
IRQ71
87
CAN1_RX0
0x0000_015C
IRQ72
88
CAN1_RX1
0x0000_0160
IRQ73
89
CAN1_SCE
0x0000_0164
7.3.2. External Interrupt and Event (EXTI)
The EXTI contains 23 independent edge detectors and generates 28 interrupt requests or
events to the processor. The EXTI has three trigger types for the 23 edge detectors: rising
edge, falling edge and both edges. Each edge detector in the EXTI can be configured and
masked independently. The figure below is the block diagram of EXTI.
GD32F1x0 User Manual
129
Figure 7-1. Block diagram of EXTI.
EXTI Line0~22 Edge
detector
Polarity
Control Software
Trigger
Interrupt Mask
Control
Event
Generate Event Mask
Control
To NVIC
To Wakeup Unit
The EXTI trigger source includes 16 lines from I/O pins and 8 lines for GD32F130xx and
GD32F150xx devices (including LVD, RTC, USBD, USART, CEC and CMP, please refer to
Table 7-4 for detail) or 7 lines for GD32F170xx and GD32F190xx devices (including LVD,
RTC, USART, CEC and CMP, please refer to Table 7-5 for detail) from the internal modules.
All GPIO pins can be selected as an EXTI trigger source by configuring SYSCFG_EXTISSx
registers in SYSCFG module (please refer to System section for detail).
EXTI can provide not only interrupts but also event signals to the processor. The Cortex-M3
processor fully implements the Wait-For-Interrupt (WFI), Wait-For-Event (WFE) and the Send
Event (SEV) instructions. There is a Wake-up Interrupt Controller (WIC) in chip, which enables
the processor and NVIC to be put into a very low-power sleep mode leaving the WIC to identify
and prioritize interrupts and events. EXTI can be used to wake up the processor and the
whole system when some expected events occur, such as a special I/O pin toggling or RTC
alarm.
The internal trigger sources from CEC and USART are able to generate event for waking up
the system. However, the two modules are also requested to generate a synchronous
interrupt for the processor to wake up the CPU from Deep-sleep mode. Both internal trigger
lines can be masked by setting corresponding INTEN and EVEN registers in EXTI module.
Hardware Trigger
GD32F1x0 User Manual
130
Hardware trigger may be used to detect the voltage change of external or internal signals.
The software should follow these steps to use this function:
1. Configure EXTI sources in SYSCFG module based on application requirement.
2. Configure EXTI_RTEN and EXTI_FTEN to enable the rising or falling detection on
related pins. (Software may set both RTENx and FTENx for a pin at the same time to detect
both rising and falling changes on this pin).
3. Enable interrupts or events by setting related EXTI_INTEN or EXTI_EVEN bits.
4. EXTI starts to detect changes on the configured pins. The related PDx bits in EXTI_PD
will be set when desired change is detected on these pins and thus, trigger interrupt or event
for software. The software should response to the interrupts or events and clear these PDx
bits.
Software Trigger
Software may also trigger EXTI interrupts or events following these steps:
1. Enable interrupts or events by setting related EXTI_INTEN or EXTI_EVEN bits.
2. Set SWIENx bits in EXTI_SWIEN register. The related PD bits will be set immediately
and thus, trigger interrupts or events. Software should response to these interrupts, and clear
related PDx bits.
Table 7-4. EXTI source of GD32F130xx and GD32F150xx devices
EXTI Line Number
Source
Attrubute
0
PA0 / PB0 / PC0 / PF0
External
1
PA1 / PB1 / PC1 / PF1
External
2
PA2 / PB2 / PC2 / PD2
External
3
PA3 / PB3 / PC3
External
4
PA4 / PB4 / PC4 / PF4
External
5
PA5 / PB5 / PC5 / PF5
External
6
PA6 / PB6 / PC6 / PF6
External
7
PA7 / PB7 / PC7 / PF7
External
8
PA8 / PB8 / PC8
External
9
PA9 / PB9 / PC9
External
10
PA10 / PB10 / PC10
External
11
PA11 / PB11 / PC11
External
12
PA12 / PB12/ PC12
External
13
PA13 / PB13 / PC13
External
14
PA14 / PB14 / PC14
External
15
PA15 / PB15 / PC15
External
16
LVD
External
17
RTC Alarm
External
18
USBD Wakeup
External
19
RTC tamper and Timestamp
External
20
Reserved
Reserved
21
CMP0 output
External
22
CMP1 output
External
GD32F1x0 User Manual
131
EXTI Line Number
Source
Attrubute
23
Reserved
Reserved
24
Reserved
Reserved
25
USART0 Wakeup
Internal
26
Reserved
Reserved
27
CEC Wakeup
Internal
Table 7-5. EXTI source of GD32F170xx and GD32F190xx devices
EXTI Line Number
Source
Attrubute
0
PA0 / PB0 / PC0 / PF0
External
1
PA1 / PB1 / PC1 / PF1
External
2
PA2 / PB2 / PC2 / PD2
External
3
PA3 / PB3 / PC3
External
4
PA4 / PB4 / PC4 / PF4
External
5
PA5 / PB5 / PC5 / PF5
External
6
PA6 / PB6 / PC6 / PF6
External
7
PA7 / PB7 / PC7 / PF7
External
8
PA8 / PB8 / PC8
External
9
PA9 / PB9 / PC9
External
10
PA10 / PB10 / PC10
External
11
PA11 / PB11 / PC11
External
12
PA12 / PB12/ PC12
External
13
PA13 / PB13 / PC13
External
14
PA14 / PB14 / PC14
External
15
PA15 / PB15 / PC15
External
16
LVD
External
17
RTC Alarm
External
18
Reserved
Reserved
19
RTC tamper and Timestamp
External
20
Reserved
Reserved
21
CMP0 output
External
22
CMP1 output
External
23
Reserved
Reserved
24
Reserved
Reserved
25
USART0 Wakeup
Internal
26
Reserved
Reserved
27
CEC Wakeup
Internal
7.4. Interrupts and EXTI registers
7.4.1. Interrupt Enable register (EXTI_INTEN)
Address offset: 0x00
GD32F1x0 User Manual
132
Reset value: 0x0F90 0000
This register has to be accessed by word(32-bit).
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
INTEN2
7
INTEN2
6
INTEN2
5
INTEN2
4
INTEN2
3
INTEN2
2
INTEN2
1
INTEN2
0
INTEN1
9
INTEN1
8
INTEN1
7
INTEN1
6
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
INTEN1
5
INTEN1
4
INTEN1
3
INTEN1
2
INTEN1
1
INTEN1
0
INTEN9
INTEN8
INTEN7
INTEN6
INTEN5
INTEN4
INTEN3
INTEN2
INTEN1
INTEN0
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31:28
Reserved
Must be kept at reset value
27: 0
INTENx
Interrupt mask bit
0: Interrupt from Linex is disabled
1: Interrupt from Linex is enabled
7.4.2. Event enable register (EXTI_EVEN)
Address offset: 0x04
Reset value: 0x0000 0000
This register has to be accessed by word(32-bit).
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
EVEN2
7
EVEN2
6
EVEN2
5
EVEN2
4
EVEN2
3
EVEN2
2
EVEN2
1
EVEN2
0
EVEN1
9
EVEN1
8
EVEN1
7
EVEN1
6
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
EVEN1
5
EVEN1
4
EVEN1
3
EVEN1
2
EVEN1
1
EVEN1
0
EVEN9
EVEN8
EVEN7
EVEN6
EVEN5
EVEN4
EVEN3
EVEN2
EVEN1
EVEN0
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31:28
Reserved
Must be kept at reset value
27: 0
EVENx
Event enable bit
0: Event from Linex is disabled
1: Event from Linex is enabled
7.4.3. Rising edge trigger enable register (EXTI_RTEN)
Address offset: 0x08
GD32F1x0 User Manual
133
Reset value: 0x0000 0000
This register has to be accessed by word(32-bit).
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
RTEN22
RTEN21
Reserved
RTEN19
RTEN18
RTEN17
RTEN16
rw
rw
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RTEN15
RTEN14
RTEN13
RTEN12
RTEN11
RTEN10
RTEN9
RTEN8
RTEN7
RTEN6
RTEN5
RTEN4
RTEN3
RTEN2
RTEN1
RTEN0
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31:23
Reserved
Must be kept at reset value
22:21
RTENx
Rising edge trigger enable
0: Rising edge of Linex is not valid
1: Rising edge of Linex is valid as an interrupt/event request
20
Reserved
Must be kept at reset value
19
RTEN19
Rising edge trigger enable
0: Rising edge of Line19 is not valid
1: Rising edge of Line19 is valid as an interrupt/event request
18
RTEN18
Rising edge trigger enable
This bit is valid only for GD32F150xx device.
0: Rising edge of Line18 is invalid
1: Rising edge of Line18 is valid as an interrupt/event request
17: 0
RTENx
Rising edge trigger enable
0: Rising edge of Linex is invalid
1: Rising edge of Linex is valid as an interrupt/event request
7.4.4. Falling edge trigger enable register (EXTI_FTEN)
Address offset: 0x0C
Reset value: 0x0000 0000
This register has to be accessed by word(32-bit).
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
FTEN22
FTEN21
Reserved
FTEN19
FTEN18
FTEN17
FTEN16
rw
rw
rw
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
FTEN15
FTEN14
FTEN13
FTEN12
FTEN11
FTEN10
FTEN9
FTEN8
FTEN7
FTEN6
FTEN5
FTEN4
FTEN3
FTEN2
FTEN1
FTEN0
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
GD32F1x0 User Manual
134
Bits
Fields
Descriptions
31: 23
Reserved
Must be kept at reset value
22: 21
FTENx
Falling edge trigger enable
0: Falling edge of Linex is invalid
1: Falling edge of Linex is valid as an interrupt/event request
20
Reserved
Must be kept at reset value
19
FTEN19
Falling edge trigger enable
0: Falling edge of Line19 is invalid
1: Falling edge of Line19 is valid as an interrupt/event request
18
FTEN18
Falling edge trigger enable
This bit is valid only for GD32F150xx device.
0: Falling edge of Line18 is invalid
1: Falling edge of Line18 is valid as an interrupt/event request
17: 0
FTENx
Falling edge trigger enable
0: Falling edge of Linex is invalid
1: Falling edge of Linex is valid as an interrupt/event request
7.4.5. Software interrupt event register (EXTI_SWIEV)
Address offset: 0x10
Reset value: 0x0000 0000
This register has to be accessed by word(32-bit).
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
SWIEV2
2
SWIEV2
1
Reserve
d
SWIEV1
9
SWIEV1
8
SWIEV1
7
SWIEV1
6
rw
rw
rw
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
SWIEV1
5
SWIEV1
4
SWIEV1
3
SWIEV1
2
SWIEV1
1
SWIEV1
0
SWIEV
9
SWIEV
8
SWIEV
7
SWIEV6
SWIEV5
SWIEV4
SWIEV3
SWIEV2
SWIEV1
SWIEV0
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31:23
Reserved
Must be kept at reset value
22: 21
SWIEVx
Interrupt/Event software trigger
0: Deactivate the EXTIx software interrupt/event request
1: Activate the EXTIx software interrupt/event request
20
Reserved
Must be kept at reset value
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135
19: 0
SWIEVx
Interrupt/Event software trigger
0: Deactivate the EXTIx software interrupt/event request
1: Activate the EXTIx software interrupt/event request
7.4.6. Pending register (EXTI_PD)
Address offset: 0x14
Reset value: undefined
This register has to be accessed by word(32-bit).
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
PD22
PD21
Reserved
PD19
PD18
PD17
PD16
rc_w1
rc_w1
rc_w1
rc_w1
rc_w1
rc_w1
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
PD15
PD14
PD13
PD12
PD11
PD10
PD9
PD8
PD7
PD6
PD5
PD4
PD3
PD2
PD1
PD0
rc_w1
rc_w1
rc_w1
rc_w1
rc_w1
rc_w1
rc_w1
rc_w1
rc_w1
rc_w1
rc_w1
rc_w1
rc_w1
rc_w1
rc_w1
rc_w1
Bits
Fields
Descriptions
31: 23
Reserved
Must be kept at reset value
22: 21
PDx
Interrupt pending status
0: EXIT Linex is not triggered
1: EXIT Linex is triggered
This bit is cleared to 0 by writing 1 to it.
20
Reserved
Must be kept at reset value
19: 0
PDx
Interrupt pending status
0: EXIT Linex is not triggered
1: EXIT Linex is triggered
This bit is cleared to 0 by writing 1 to it.
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136
8. Direct memory access controller (DMA)
8.1. Introduction
The direct memory access (DMA) controller provides a hardware method of transferring data
between peripherals and memory or between memory and memory without intervention from
the CPU, thereby freeing up bandwidth for other system functions. Data can be quickly moved
by DMA between peripherals and memory as well as memory and memory without any CPU
actions. There are 7 channels in the DMA controller. Each channel is assigned a specific or
multiple target peripheral devices for memory access request management. An arbiter is
implemented inside to handle the priority among DMA requests.
Both the DMA controller and the CortexTM-M3 core implement data access through the system
bus. An arbitration mechanisim is implemented to solve the competition between these two
masters. When the same peripheral is targeted, the CPU access will be suspended for some
specific bus cycles. A round-robin scheduling algorithm is utilized in the bus matrix to guaranty
at least half the bandwidth to the CPU.
8.2. Main features
Programmable length of data to be transferred, max to 65536
7 channels and each channel is configurable
AHB and APB peripherals, FLASH, SRAM can be accessed as source and destination
Each channel is connected to fixed hardware DMA request
The priorities of DMA channel requests are determined by software configuration and
hardware channel number
Support peripheral to memory, memory to peripheral, and memory to memory transfers
Three types of event flags and one single interrupt request for each channel
Configurable transfer size of source and destination in a channel
8.3. Function description
8.3.1. DMA transfers
The handshake mechanism between the DMA controller and peripherals is based on the
request signal and the acknowledge signal. The request singal indicates the peripheral is
requesting for DMA access, while the acknowledge signal indicates the DMA controller has
accessed the peripheral. When the DMA controller receives two or more requests at a time,
the requests are served depending on the channel priorities. Each DMA transfer consists of
two operations, including the loading of data from the source and the storage of the loaded
data to the destination. The source and destination addresses are computed by the DMA
GD32F1x0 User Manual
137
controller based on the programmed values in the DMA_CHxPADDR, DMA_CHxMADDR,
and DMA_CHxCTL0 registers. For details, see Chapter 8.3.3. The DMA_CHxCNT register
controls how many transfers to be transmitted on the channel. The PWIDTH and MWIDTH
bits in the DMA_CHxCTL0 register determine how many bytes to be transmitted in a transfer.
Suppose DMA_CHxCNT is 4, and both PNAGA and MNAGA are set. The DMA transfer
operations for each combination of PWIDTH and MWIDTH are shown in the following table.
Table 8-1. DMA transfer operations
Transfer size
Transfer operations
Source
Destination
Source
Destination
32 bits
32 bits
1: Read B3B2B1B0[31:0] @0x0
2: Read B7B6B5B4[31:0] @0x4
3: Read BBBAB9B8[31:0] @0x8
4: Read BFBEBDBC[31:0] @0xC
1: Write B3B2B1B0[31:0] @0x0
2: Write B7B6B5B4[31:0] @0x4
3: Write BBBAB9B8[31:0] @0x8
4: Write BFBEBDBC[31:0] @0xC
32 bits
16 bits
1: Read B3B2B1B0[31:0] @0x0
2: Read B7B6B5B4[31:0] @0x4
3: Read BBBAB9B8[31:0] @0x8
4: Read BFBEBDBC[31:0] @0xC
1: Write B1B0[15:0] @0x0
2: Write B5B4[15:0] @0x2
3: Write B9B8[15:0] @0x4
4: Write BDBC[15:0] @0x6
32 bits
8 bits
1: Read B3B2B1B0[31:0] @0x0
2: Read B7B6B5B4[31:0] @0x4
3: Read BBBAB9B8[31:0] @0x8
4: Read BFBEBDBC[31:0] @0xC
1: Write B0[7:0] @0x0
2: Write B4[7:0] @0x1
3: Write B8[7:0] @0x2
4: Write BC[7:0] @0x3
16 bits
32 bits
1: Read B1B0[15:0] @0x0
2: Read B3B2[15:0] @0x2
3: Read B5B4[15:0] @0x4
4: Read B7B6[15:0] @0x6
1: Write 0000B1B0[31:0] @0x0
2: Write 0000B3B2[31:0] @0x4
3: Write 0000B5B4[31:0] @0x8
4: Write 0000B7B6[31:0] @0xC
16 bits
16 bits
1: Read B1B0[15:0] @0x0
2: Read B3B2[15:0] @0x2
3: Read B5B4[15:0] @0x4
4: Read B7B6[15:0] @0x6
1: Write B1B0[15:0] @0x0
2: Write B3B2[15:0] @0x2
3: Write B5B4[15:0] @0x4
4: Write B7B6[15:0] @0x6
16 bits
8 bits
1: Read B1B0[15:0] @0x0
2: Read B3B2[15:0] @0x2
3: Read B5B4[15:0] @0x4
4: Read B7B6[15:0] @0x6
1: Write B0[7:0] @0x0
2: Write B2[7:0] @0x1
3: Write B4[7:0] @0x2
4: Write B6[7:0] @0x3
8 bits
32 bits
1: Read B0[7:0] @0x0
2: Read B1[7:0] @0x1
3: Read B2[7:0] @0x2
4: Read B3[7:0] @0x3
1: Write 000000B0[31:0] @0x0
2: Write 000000B1[31:0] @0x4
3: Write 000000B2[31:0] @0x8
4: Write 000000B3[31:0] @0xC
8 bits
16 bits
1: Read B0[7:0] @0x0
2: Read B1[7:0] @0x1
3: Read B2[7:0] @0x2
4: Read B3[7:0] @0x3
1, Write 00B0[15:0] @0x0
2, Write 00B1[15:0] @0x2
3, Write 00B2[15:0] @0x4
4, Write 00B3[15:0] @0x6
8 bits
8 bits
1: Read B0[7:0] @0x0
2: Read B1[7:0] @0x1
3: Read B2[7:0] @0x2
4: Read B3[7:0] @0x3
1, Write B0[7:0] @0x0
2, Write B1[7:0] @0x1
3, Write B2[7:0] @0x2
4, Write B3[7:0] @0x3
8.3.2. Arbitration among channels
When two or more requests are received at a time, the arbiter determines which request is
served based on the priorities of channels. There are two-stage priorities, including the
software priority and the hardware priority. The software priority is configured by the PRIO[1:0]
bits in the DMA_CHxCTL0 register. There are four levels, including low, medium, high, and
ultra high. And the hardware priority is fixed. The lower the channel number is, the higher the
channel priority is. For instance, channel 0 has the higher priority over channel 2. The software
priority is more significant than the hardware priority. If two channels are configured in
different software priorities, the channel with higher software priority is served. If two channels
are configured in the same software priority, the channel with higher hardware priority is
served.
GD32F1x0 User Manual
138
8.3.3. Next address generation algorithm
PWIDTH and MWIDTH bits in the DMA_CHxCTL0 register are used for configuring the
transfer data size of peripheral and memory. PNAGA and MNAGA bits in the DMA_CHxCTL0
register are used to configure the next address generation algorithm of peripheral and
memory. There are two algorithms including the fixed address mode and the increasing
address mode. In the fixed address mode, the next address is equal to the current address.
In the increasing address mode, the next address is the current address plus 1 or 2 or 4,
depending on the transfer data size.
8.3.4. Circulation mode
Circulation mode is implemented for circular data flows (for example, ADC scan mode). The
feature can be enabled by configuring the CMEN bit in the DMA_CHxCTL0 register. If enabled,
the remain counter of the channel is automatically reloaded with the initial programmed value
when it reaches zero. So the DMA requests are always served.
8.3.5. Memory to memory mode
The memory to memory mode is enabled by setting the M2M bit in the DMA_CHxCTL0
register. In this mode, the DMA channel can also work without being triggered by a request
from a peripheral. The DMA channel starts transferring as soon as it is enabled by setting the
CHEN bit in the DMA_CHxCTL0 register, and stops when the DMA_CHxCNT register
reaches zero.
8.3.6. Interrupt requests
Each DMA channel has a dedicated interrupt. There are three types of interrupt event,
including transfer complete, half transfer complete, and transfer error. An interrupt may be
produced when any type of interrupt event occurs on the channel. Each interrupt event has a
dedicated flag bit in the DMA_INTF register, a dedicated clear bit in the DMA_INTC register,
and a dedicated enable bit in the DMA_CHxCTL0 register. The relationship is described in
the following table.
Table 8-2. DMA interrupt event
Interrupt event
Flag bit
Clear bit
Enable bit
Transfer complete
FTFIF
FTFIFC
FTFIE
Half transfer complete
HTFIF
HTFIFC
HTFIE
Transfer error
TAEIF
TAEIFC
TAEIE
GD32F1x0 User Manual
139
Figure 8-1. DMA interrupt generation logic
FTFIFx
FTFIEN
HTFIFx
HTFIEN
TAEIFx
TAEIEN
INTERRUPTx
Note: “x” indicates channel number (x=0…6).
The transfer error event occurs when the DMA controller accesses a reserved address space.
At the moment, the channel is automatically shut down through hardware clear of the CHEN
bit in the DMA_CHxCTL0 register.
8.3.7. DMA channel configuration procedure
The following sequence should be followed to configure a DMA channel.
1. Configure the DMA_CHxPADDR register for setting the peripheral address.
2. Configure the DMA_CHxMADDR register for setting the memory address.
3. Configure the DMA_CHxCNT register for setting the total transfer data number.
4. Configure the DMA_CHxCTL0 register for channel software priority, transfer direction,
mode type, data size and interrupt type.
5. Configure the DMA_CHxCTL0 register for setting the CHEN bit.
8.3.8. DMA request mapping
Several requests from peripherals may be mapped to one DMA channel. They are logically
ORed before entering the DMA. For details, see the following figure. The request of each
peripheral can be independently enabled or disabled by programming the registers of the
corresponding peripheral. The user has to ensure that only one request is enabled at a time
on one channel.
GD32F1x0 User Manual
140
Figure 8-2. DMA request mapping
ADC(1)
TIMER1_CH2
TIMER16_CH0(1)
TIMER16_UP(1)
ADC(2)
SPI0_RX
USART0_TX(1)
I2C0_TX
TIMER0_CH0
TIMER1_UP
TIMER2_CH2
TIMER16_CH0(2)
TIMER16_UP(2)
SPI0_TX
USART0_RX(1)
I2C0_RX
TIMER0_CH1
TIMER1_CH1
TIMER2_CH3
TIMER2_UP
TIMER5_UP
DAC0
TIMER15_CH0(1)
TIMER15_UP(1)
SPI1_RX
USART0_TX(2)
USART1_TX
I2C1_TX
TIMER0_CH3
TIMER0_TRIG
TIMER0_COM
TIMER1_CH3
TIMER2_CH0
TIMER2_TRIG
TIMER15_CH0(2)
TIMER15_UP(2)
SPI1_TX
USART0_RX(2)
USART1_RX
I2C1_RX
TIMER0_CH2
TIMER0_UP
TIMER1_CH0
TIMER14_CH0
TIMER14_UP
TIMER14_TRIG
TIMER14_CH1
SPI2_RX
I2C2_TX
DAC1(For
GD32F170/190d
evices)
SPI2_TX
I2C2_RX
Channel 0
MEMTOMEM0
Channel 1
MEMTOMEM1
Channel 2
MEMTOMEM2
Channel 3
MEMTOMEM3
Channel 4
MEMTOMEM4
Channel 5
MEMTOMEM5
Channel 6
MEMTOMEM6
Hardware
priority
high
low
1. When the corresponding remapping bit in the SYSCFG_CFG0 register is cleared, the
GD32F1x0 User Manual
141
request is mapped on the channel.
2. When the corresponding remapping bit in the SYSCFG_CFG0 register is set, the request
is mapped on the channel.
The following table lists the support request from peripheral of each channel.
Table 8-3. Summary of DMA requests for each channel
Peripheral
Channel 0
Channel 1
Channel 2
Channel 3
Channel 4
Channel 5
Channel 6
ADC
ADC(1)
ADC(2)
●
●
●
●
●
SPI/I2S
●
SPI0_RX
SPI0_TX
SPI1_RX
SPI1_TX
SPI2_RX
SPI2_TX
USART
●
USART0_TX(1
)
USART0_RX(1
)
USART0_TX(2
)
USART1_TX
USART0_RX(2
)
USART1_RX
●
●
I2C
●
I2C0_TX
I2C0_RX
I2C1_TX
I2C1_RX
I2C2_TX
I2C2_RX
TIMER0
●
TIMER0_CH0
TIMER0_CH1
TIMER0_CH3
TIMER0_TRIG
TIMER0_COM
TIMER0_CH2
TIMER0_UP
●
●
TIMER1
TIMER1_CH2
TIMER1_UP
TIMER1_CH1
TIMER1_CH3
TIMER1_CH0
●
●
TIMER2
●
TIMER2_CH2
TIMER2_CH3
TIMER2_UP
TIMER2_CH0
TIMER2_TRIG
●
●
●
TIMER5/DA
C
●
●
TIMER5_UP
DAC0
●
●
DAC1 (For
GD32F170/19
0devices)
●
TIMER14
●
●
●
●
TIMER14_CH0
TIMER14_UP
TIMER14_TRI
G
TIMER14_CO
M
●
●
TIMER15
●
●
TIMER15_CH0
(1)
TIMER15_UP(
1)
TIMER15_CH0
(2)
TIMER15_UP(
2)
●
●
●
TIMER16
TIMER16_CH0
(1)
TIMER16_UP(
1)
TIMER16_CH0
(2)
TIMER16_UP(
2)
●
●
●
●
●
8.4. DMA registers
8.4.1. Interrupt flag register (DMA_INTF)
Address offset: 0x00
Reset value: 0x0000 0000
This register can be accessed by byte(8-bit), half-word(16-bit) and word(32-bit) .
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
TAEIF6
HTFIF6
FTFIF6
GIF6
TAEIF5
HTFIF5
FTFIF5
GIF5
TAEIF4
HTFIF4
FTFIF4
GIF4
r
r
r
r
r
r
r
r
r
r
r
r
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
TAEIF3
HTFIF3
FTFIF3
GIF3
TAEIF2
HTFIF2
FTFIF2
GIF2
TAEIF1
HTFIF1
FTFIF1
GIF1
TAEIF0
HTFIF0
FTFIF0
GIF0
r
r
r
r
r
r
r
r
r
r
r
r
r
r
r
r
Bits
Fields
Descriptions
GD32F1x0 User Manual
142
31:28
Reserved
Must be kept at reset value
27/23/19/
15/11/7/3
TAEIFx
Transfer access error flag of channel x (x=0…6)
Hardware set and software cleared by configuring DMA_INTC register.
0: Error has not occurred on channel x
1: Error has occurred on channel x
26/22/18/
14/10/6/2
HTFIFx
Half transfer finish flag of channel x (x=0…6)
Hardware set and software cleared by configuring DMA_INTC register.
0: Half number of transfer has not completed on channel x
1: Half number of transfer has completed on channel x
25/21/17/
13/9/5/1
FTFIFx
Full transfer finish flag of channel x (x=0…6)
Hardware set and software cleared by configuring DMA_INTC register.
0: Transfer has not completed on channel x
1: Transfer has completed on channel x
24/20/16/
12/8/4/0
GIFx
Global interrupt flag of channel x (x=0…6)
Hardware set and software cleared by configuring DMA_INTC register.
0: None of TAEIF, HTFIF or FTFIF occurs on channel x
1: At least one of TAEIF, HTFIF or FTFIF occurs on channel x
8.4.2. Interrupt flag clear register (DMA_INTC)
Address offset: 0x04
Reset value: 0x0000 0000
This register can be accessed by byte(8-bit), half-word(16-bit) and word(32-bit) .
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
TAEIFC6
HTFIFC6
FTFIFC6
GIC6
TAEIFC5
HTFIFC5
FTFIFC5
GIC5
TAEIFC4
HTFIFC4
FTFIFC4
GIC4
w
w
w
w
w
w
w
w
w
w
w
w
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
TAEIFC3
HTFIFC3
FTFIFC3
GIC3
TAEIFC2
HTFIFC2
FTFIFC2
GIC2
TAEIFC1
HTFIFC1
FTFIFC1
GIC1
TAEIFC0
HTFIFC0
FTFIFC0
GIC0
w
w
w
w
w
w
w
w
w
w
w
w
w
w
w
w
Bits
Fields
Descriptions
31:28
Reserved
Must be kept at reset value
27/23/19/
15/11/7/3
TAEIFCx
Clear bit for transfer access error flag of channel x (x=0…6)
0: No effect
1: Clear TAEIFx bit in the DMA_INTF register
26/22/18/
14/10/6/2
HTFIFCx
Clear bit for half transfer finish flag of channel x (x=0…6)
0: No effect
1: Clear HTFIFx bit in the DMA_INTF register
25/21/17/
FTFIFCx
Clear bit for Full transfer finish flag of channel x (x=0…6)
GD32F1x0 User Manual
143
13/9/5/1
0: No effect
1: Clear FTFIFx bit in the DMA_INTF register
24/20/16/
12/8/4/0
GICx
Clear global interrupt flag of channel x (x=0…6)
0: No effect
1: Clear GIFx, TAEIFx, HTFIFx and FTFIFx bits in the DMA_INTF register
8.4.3. Channel x control registers (DMA_CHxCTL0)
x = 0..6, where x is channel number
Address offset: 0x08 + 0d20 × (x)
Reset value: 0x0000 0000
This register can be accessed by byte(8-bit), half-word(16-bit) and word(32-bit) .
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Res.
M2M
PRIO[1:0]
MWIDTH[1:0]
PWIDTH[1:0]
MNAGA
PNAGA
CMEN
TM
TAEIE
HTFIE
FTFIE
CHEN
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31:15
Reserved
Must be kept at reset value
14
M2M
Memory to Memory Mode
0: Disable Memory to Memory Mode
1: Enable Memory to Memory Mode
13:12
PRIO[1:0]
Priority Level of this channel
00: Low
01: Medium
10: High
11: Ultra high
11:10
MWIDTH[1:0]
Transfer data size of memory
00: 8-bit
01: 16-bit
10: 32-bit
11: Reserved
9:8
PWIDTH[1:0]
Transfer data size of peripheral
00: 8-bit
01: 16-bit
10: 32-bit
11: Reserved
7
MNAGA
Next address generation algorithm of memory
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0: Fixed address mode
1: Increasing address mode
6
PNAGA
Next address generation algorithm of peripheral
0: Fixed address mode
1: Increasing address mode
5
CMEN
Circulation mode enable
0: Disable circulation mode.
1: Enable circulation mode
4
TM
Transfer mode
0: Read from peripheral and write to memory
1: Read from memory and write to peripheral
3
TAEIE
Enable bit for tranfer access error interrupt
0: Disable the channel error interrupt
1: Enable the channel error interrupt
2
HTFIE
Enable bit for half transfer finish interrupt
0: Disable HT interrupt
1: Enable HT interrupt
1
FTFIE
Enable bit for full transfer finish interrupt
0: Disable TC interrupt
1: Enable TC interrupt
0
CHEN
Channel enable
0: Disable channel
1: Enable channel
8.4.4. Channel x counter registers (DMA_CHxCNT)
x = 0..6, where x is channel number
Address offset: 0x0C + 0d20 × (x)
Reset value: 0x0000 0000
This register can be accessed by byte(8-bit), half-word(16-bit) and word(32-bit) .
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
CNT[15:0]
rw
Bits
Fields
Descriptions
31:16
Reserved
Must be kept at reset value
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145
15:0
CNT[15:0]
Transfer counter
This register signifies the number of remaining data to be transferred by the DMA. It
can be modified only when the channel is disabled. Once the data transfer is
started, this register is read-only. After each DMA transfer, CNT is decreamented by
1. When CNT = 0, no DMA transfer can be issued whether the corresponding
channel is enabled or not. CNT can be reloaded automatically to the original value
after the overall DMA transfer operation depending on the channel reload
configuration previously specified.
8.4.5. Channel x peripheral base address registers (DMA_CHxPADDR)
x = 0..6, where x is channel number
Address offset: 0x10 + 0d20 × (x)
Reset value: 0x0000 0000
This register can be accessed by byte(8-bit), half-word(16-bit) and word(32-bit) .
Note: Do not configure this register when channel is enabled.
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
PADDR[31:16]
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
PADDR[15:0]
rw
Bits
Fields
Descriptions
31:0
PADDR[31:0]
Peripheral base address
When PWIDTH is 01 (16-bit), PADDR[0] is ignored. Access is automatically aligned
to a half word address.
When PWIDTH is 10 (32-bit), PADDR[1:0] is ignored. Access is automatically
aligned to a word address.
8.4.6. Channel x memory base address registers (DMA_CHxMADDR)
x = 0..6, where x is channel number
Address offset: 0x14 + 0d20 × (x)
Reset value: 0x0000 0000
This register can be accessed by byte(8-bit), half-word(16-bit) and word(32-bit) .
Note: Do not configure this register when channel is enabled.
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
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MADDR[31:16]
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
MADDR[15:0]
rw
Bits
Fields
Descriptions
31:0
MADDR[31:0]
Memory base address
When MWIDTH is 01 (16-bit), MADDR[0] is ignored. Access is automatically aligned
to a half word address.
When MWIDTH is 10 (32-bit), MADDR[1:0] is ignored. Access is automatically
aligned to a word address.
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9. Timer (TIMERx)
Timers (TIMERx) are devided into six sorts.
TIMER
TIMER0
TIMER1/2
TIMER5
TIMER13
TIMER14
TIMER15/1
6
TYPE
Advanced
General(1)
Basic
General(2)
General(3)
General(4)
Prescaler
16-bit
16-bit
16-bit
16-bit
16-bit
16-bit
Counte mode
UP,DOWN,
Center-
aligned
UP,DOWN,
Center-
aligned
UP
ONLY
UP ONLY
UP ONLY
UP ONLY
Repetition
●
×
×
×
●
●
Capture/
compare CH
4
4
0
1
2
1
Output
Complementar
y & Deadtime
●
×
×
×
●
●
Break
●
×
×
×
●
●
Single Pulse
●
●
×
×
●
●
Quadrature
Decoder
●
●
×
×
×
×
Slave
Controller
●
●
×
×
●
×
Inter
connection
●(1)
●(2)
TRGO
TO DAC
×
●(3)
×
Debug Mode
●
●
●
●
●
●
DMA
●
●
●
×
●
●
(1) TIMER0: tm14_trgo->it0; tm1_trgo->it1; tm2_trgo->it2; 0->it3
(2) TIMER1: tm0_trgo->it0; tm14_trgo->it1; tm2_trgo->it2; 0->it3;
TIMER2: tm0_trgo->it0; tm1_trgo->it1; tm14_trgo->it2; 0->it3;
(3) TIMER14:tm1_trgo->it0; tm2_trgo->it1; 0->it2; 0->it3
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9.1. Advanced timer (TIMER0)
9.1.1. Introduction
The Advanced Timer, known as TIMER0, may be used for a variety of purposes of advanced
control. It consists of one 16-bit up/down-counter; four 16-bit capture/compare registers
(TIMER0_CHxCV), one 16-bit counter auto reload register (TIMER0_CAR) and several
control registers. They can be used for a variety of purposes including general timer, input
signal pulse width measurement or output waveform generation such as single pulse
generation or PWM output. The TIMER0 supports an Encoder Interface using a decoder with
two inputs.
The advanced (TIMER0) and general (TIMERx) timers are completely independent. They do
not share any resources but can be synchronized together.
9.1.2. Main features
16-bit down, up, down/up auto-reload counter.
16-bit programmable prescaler that allows division of the counter clock frequency by any
factor between 1 and 65536.
Up to 4 independent channels support functions including input capture, compare match
output, generation of PWM waveform (edge and center-aligned Mode), and single pulse
mode output.
Counter repetition to update the timer registers only after a given number of cycles of the
counter.
Break input to trigger the timer’s output signals to a known state.
Interrupt/DMA generation by update, trigger event, input capture event, output compare
match event or break input
Programmable dead-time for output match.
Synchronization circuit to control TIMER0 with external signals or to interconnect several
timers together.
Encoder interface controller with two inputs using quadrature decoder
TIMER0 Master/Slave mode controller
9.1.3. Function description
Figure below provides details on the internal configuration of the advanced timer.
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Figure 9-1. Advanced timer block diagram
Trigger
Controller
Mode Slave
Controller
Encoder
Interface
ITI0
ITI1
ITI2
ITI3
ETI Edge Detector
Polarity Selection
Prescaler
Input Filter
CI0FE0
CI1FE0
CI0F_ED
TRGO
CH0
CH1
CH2
CH3
BRKIN Polarity Selection
XOR
Input Filter Edge Detector Prescaler
Capture Register
Compare Register
Prescaler
Counter
AutoReload
Register
Repetition
counter
Repeat
Register
DTG Output
Control
CH0
CH0_N
CH1
CH1_N
CH2
CH2_N
CH3
Reset, Enable, Up/Down, Count
Prescaler counter
The prescaler can divide the timer clock (TIMER_CK) to the counter clock (CNT_CLK) by any
factor between 1 and 65536. It is controlled through prescaler register (TIMER0_PSC) which
can be changed on the fly but be taken into account at the next update event.
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Figure 9-2. Counter timing diagram with prescaler division change from 1 to 2
TIMER_CK
CEN
CNT_CLK
CNT_REG
Reload Pulse
Prescaler CNT
Prescaler BUF
Prescaler CR
F7 F8 F9 FA FB FC 01 02 03 04
01
0 1
0 0 1 0 1 0 1 0 1
modify scaler Vaule
Figure 9-3. Counter timing diagram with prescaler division change from 1 to 4
TIMER_CK
CEN
CNT_CLK
CNT_REG
Reload Pulse
Prescaler CNT
Prescaler BUF
Prescaler CR
F7 F8 F9 FA FB FC 00 01
03
0 3
0 0 1 2 3 0 1 2 3
modify PSC Vaule
Upcounting mode
In this mode the counter counts continuously from 0 to the counter-reload value, which is
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151
defined in the TIMER0_CAR register, in a count-up direction. Once the counter reaches the
counter reload value, the counter restarts to count once again from 0. If the repetition counter
is set, the update events generated after the number (TIMERx_CREP+1) of overflow. Else
the update event is generated at each counter overflow.The counting direction bit DIR in the
TIMER0_CTL0 register should be set to 0 for the upcounting mode.
When the update event is set by the UPG bit in the TIMER0_SWEVG register, the counter
value will be initialized to 0 and generates an update event.
If set the UPDIS bit in TIMER0_CTL0 register, the update event is disabled.
When an update event occurs, all the registers (repetition counter, autoreload register,
prescaler register) are updated.
The following figures show some examples of the counter behavior for different clock
frequencies when TIMERx_CAR=0x63.
Figure 9-4. Counter timing diagram, internal clock divided by 1
TIMER_CK
CEN
CNT_CLK
CNT_REG
overflow
5E 5F 60 61 62 63 00 01 02 03 04 05 06 07
Update event (UPE)
Update interrupt flag (UPIF)
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Figure 9-5. Counter timing diagram, internal clock divided by 2
TIMER_CK
CEN
CNT_CLK
CNT_REG
overflow
61
Update event (UPE)
Update interrupt flag (UPIF)
62 63 00 01 02 03 04
Figure 9-6. Counter timing diagram, internal clock divided by 4
TIMER_CK
CEN
CNT_CLK
CNT_REG
overflow
62
Update event (UPE)
Update interrupt flag (UPIF)
63 00 01
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Figure 9-7. Counter timing diagram, internal clock divided by N
TIMER_CK
CNT_CLK
CNT_REG
overflow
31
Update event (UPE)
Update interrupt flag (UPIF)
32 00
Figure 9-8. Counter timing diagram, update event when ARSE=0
TIMER_CK
CEN
CNT_CLK
CNT_REG
overflow
5E 5F 60 61 62 63 00 01 02 03 04 05 06 07
Update event (UPE)
Update interrupt flag (UPIF)
Auto-reload register 65 63
modify CAR Vaule
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Figure 9-9. Counter timing diagram, update event when ARSE=1
TIMER_CK
CEN
CNT_CLK
CNT_REG
overflow
60 61 62 63 64 65 00 01 02 03 04 05 06 07
Update event (UPE)
Update interrupt flag (UPIF)
Auto-reload register 65 63
modify CAR Vaule
Auto-reload shadow register 65 63
Downcounting mode
In this mode the counter counts continuously from the counter-reload value, which is defined
in the TIMER0_CAR register, to 0 in a count-down direction. Once the counter reaches 0, the
counter restarts to count once again from the counter-reload value. If the repetition counter is
set, the update event generated after the number (TIMERx_CREP+1) of underflow. Else the
update event is generated at each counter underflow. The counting direction bit DIR in the
TIMER0_CTL0 register should be set to 1 for the down-counting mode.
When the update event is set by the UPG bit in the TIMER0_SWEVG register, the counter
value will be initialized to the counter-reload value and generates an update event.
If set the UPDIS bit in TIMER0_CTL0 register, the update event is disabled.
When an update event occurs, all the registers (repetition counter, autoreload register,
prescaler register) are updated.
The following figures show some examples of the counter behavior for different clock
frequencies when TIMERx_CAR=0x63.
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Figure 9-10. Counter timing diagram, internal clock divided by 1
TIMER_CK
CEN
CNT_CLK
CNT_REG
overflow
05 04 03 02 01 00 63 62 61 60 5F 5E 5D 5C
Update event (UPE)
Update interrupt flag (UPIF)
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Figure 9-11. Counter timing diagram, internal clock divided by 2
TIMER_CK
CEN
CNT_CLK
CNT_REG
overflow
002
Update event (UPE)
Update interrupt flag (UPIF)
001 000 063 062 061 060 05F
Figure 9-12. Counter timing diagram, internal clock divided by 4
TIMER_CK
CEN
CNT_CLK
CNT_REG
overflow
001
Update event (UPE)
Update interrupt flag (UPIF)
000 063 062
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Figure 9-13. Counter timing diagram, internal clock divided by N
TIMER_CK
CNT_CLK
CNT_REG
overflow
030
Update event (UPE)
Update interrupt flag (UPIF)
02F063
Figure 9-14. Counter timing diagram, update event when repetition counter is not used
TIMER_CK
CEN
CNT_CLK
CNT_REG
overflow
05 04 03 02 01 00 63 62 61 60 5F 5E 5D 5C
Update event (UPE)
Update interrupt flag (UPIF)
Auto-reload register 65 63
modify CAR Vaule
Center-aligned counting mode
In the center-aligned counting mode, the counter counts up from 0 to the counter-reload value
and then counts down to 0 alternatively. The Timer module generates an overflow event when
the counter counts to the counter-reload value subtract 1 in the up-counting mode and
generates an underflow event when the counter counts to 1 in the down-counting mode. The
counting direction bit DIR in the TIMER0_CTL0 register is read-only and indicates the
counting direction when in the center-aligned mode. The counting direction is updated by
hardware automatically.
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Setting the UPG bit in the TIMER0_SWEVG register will initialize the counter value to 0
irrespective of whether the counter is counting up or down in the center-align counting mode
and generates an update event.
The UPIF bit in the TIMERx_INTF register can be set to 1 when an underflow event at count-
down (CAM in TIMER0_CTL0 is “01”), an overflow event at count-up (CAM in TIMER0_CTL0
is “10”) or both of them occur (CAM in TIMER0_CTL0 is “11”).
If set the UPDIS bit in the TIMER0_CTL0 register, the update event is disabled.
When an update event occurs, all the registers (repetition counter, autoreload register,
prescaler register) are updated.
The following figures show some examples of the counter behavior for different clock
frequencies when TIMERx_CAR=0x5.
Figure 9-15. Counter timing diagram, internal clock divided by 1, TIMERx_CAR = 0x5
TIMER_CK
CEN
CNT_CLK
CNT_REG
overflow
04 03 02 01 00 01 02 03 04 05 04 03 02 01
Update event (UPE)
Update interrupt flag (UPIF)
underflow
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Figure 9-16. Counter timing diagram, internal clock divided by 2
TIMER_CK
CEN
CNT_CLK
CNT_REG
underflow
003
Update event (UPE)
Update interrupt flag (UPIF)
002 001 000 001 002 003 004
Figure 9-17. Counter timing diagram, internal clock divided by 4, TIMERx_CAR=0x63
TIMER_CK
CEN
CNT_CLK
CNT_REG
overflow
061
Update event (UPE)
Update interrupt flag (UPIF)
062 063 062
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Figure 9-18. Counter timing diagram, internal clock divided by N
TIMER_CK
CNT_CLK
CNT_REG
underflow
030
Update event (UPE)
Update interrupt flag (UPIF)
02F 001 000
Figure 9-19. Counter timing diagram, update event with ARSE=1(counter underflow)
TIMER_CK
CEN
CNT_CLK
CNT_REG
overflow
06 05 04 03 02 01 00 01 02 03 04 05 06 07
Update event (UPE)
Update interrupt flag (UPIF)
Auto-reload register 65 63
modify CAR Vaule
Auto-reload shadow register 65 63
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Figure 9-20. Counter timing diagram, Update event with ARSE=1 (counter overflow)
TIMER_CK
CEN
CNT_CLK
CNT_REG
overflow
7A 7B 7C 7D 7E 7F 63 62 61 60 5F 5E 5D 5C
Update event (UPE)
Update interrupt flag (UPIF)
Auto-reload register 80 63
modify CAR Vaule
Auto-reload shadow register 65 63
Counter Repetition
Counter Repetition is used to generator update event or updates the timer registers only after
a given number (N+1) of cycles of the counter, where N is CREP in TIMER0_CREP register.
The repetition counter is decremented at each counter overflow in up-counting mode, at each
counter underflow in down-counting mode or at each counter overflow and at each counter
underflow in center-aligned mode.
Setting the UPG bit in the TIMER0_SWEVG register will reload the content of CREP in
TIMER0_CREP register and generator an update event.
For odd values of CREP in center-aligned mode, the update event occurs either on the
overflow or on the under depending on when the CREP register was written and when the
counter was started. The update event generated at overflow when the CREP was written
before starting the counter, and generated at underflow when the CREP was written after
starting the counter.
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Figure 9-21. Update rate examples depending on mode and TIMERx_CREP
Center-aligned mode Upcounting
Edge-aligned mode
Downcounting
Edge-aligned mode
CREP = 0
CREP = 1
Clock selection
The following describes the Timer Module clock controller which determines the clock source
of the internal prescaler counter.
Internal timer clock TIMER_CK
The default internal clock source is the APB2 clock CK_APB2 used to drive the counter
prescaler when the slave mode is disabled. If the slave mode controller is enabled by setting
SMC field in the TIMER0_SMCFG register to an available value including 0x1, 0x2, 0x3 and
0x7, the prescaler is clocked by other clock sources selected by the TRGS field in the
TIMER0_SMCFG register and described as follows. When the slave mode selection bits SMC
are set to 0x4, 0x5 or 0x6, the internal clock TIMER_CK is the counter prescaler driving clock
source.
Figure 9-22. Control circuit in normal mode, internal clock divided by 1
TIMER_CK
CEN
CNT_CLK
CNT_REG
Reload Pulse
17 18 19 20 21 22
UPG
23 00 01 02 03 04 05 06
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Quadrature decoder
To select Quadrature Decoder mode the SMC field should be set to 0x1, 0x2 or 0x3 in the
TIMER0_SMCFG register. The Quadrature Decoder function uses two input states of the
TIMER0_CH0 and TIMER0_CH1 pins to generate the clock pulse to drive the counter
prescaler. The counting direction bit DIR is modified by hardware automatically at each
transition on the input source signal. The input source signal can be derived from the
TIMER0_CH0 pin only, the TIMER0_CH1 pin only or both TIMER0_CH0 and TIMER0_CH1
pins.
Internal trigger inputs (ITI)
The counter prescaler can count during each rising or falling edge of the ITI signal. This mode
can be selected by setting the SMC field to 0x6 in the TIMER0_SMCFG register, here the
counter will act as an event counter. The input event, known as ITI here, can be selected by
setting the TRGS field. When the ITI signal is selected as the clock source, the internal edge
detection circuitry will generate a clock pulse during each ITI signal rising or falling edge to
drive the counter prescaler.
Channel input pin (CI)
The counter prescaler can be driven to count during each rising or falling edge on the external
pin TIMER0_CIx. This mode can be selected by setting SMC field to 0x7 and the TRGS field
to 0x4, 0x5 or 0x6. Note that the CIx is derived from the TIMER0_CHx sampled by a digital
filter.
External trigger input (ETIF)
The counter prescaler can be driven to count during each rising or falling edge on the external
pin TIMER0_ETI. This mode can be selected by setting the SMC1 bit in the TIMER0_SMCFG
register to 1. The other way to select the ETIF signal as the clock source is to set the SMC
field to 0x6 and the TRGS field to 0x7 respectively. Note that the ETIF signal is derived from
the TIMER0_ETI pin sampled by a digital filter. When the clock source is selected to come
from the ETIF signal, the Trigger Controller including the edge detection circuitry will generate
a clock pulse during each ETIF signal rising edge to clock the counter prescaler.
Capture/compare channels
The TIMER0 has four independent channels which can be used as capture inputs or compare
match outputs. Each channel is built around a channel capture/compare value register
including an input stage, channel controller and an output stage.
Input capture stage
The input stage consists of a digital filter, a channel polarity selection, edge detection and a
channel prescaler. The channel 0 input signal (CI0) can be chosen to come from the
TIMER0_CH0 signal or the Excusive-OR function of the TIMER0_CH0, TIMER0_CH1 and
TIMER0_CH2 signals. The channel input signal (CIx) is sampled by a digital filter to generate
a filtered input signal CIxF. Then the channel polarity and the edge detection block can
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164
generate a CIxFEx signal for the input capture function. The effective input event number can
be set by the channel input prescaler (CHxCAPPSC).
Figure 9-23. Capture/compare channel (example: channel 0 input stage)
filter
downcounter
CI0
CH0CAPFLT
[3:0]
CHCTL0
fDTS
Edge Detector CI0F_Falling
CI0F_Rising 0
1
CH0P/
CH0NP
CHCTL2
01
CH0MS[ 1:0 ]
CHCTL0
10
11
CI0FE0
CI1FE0
ITS
divider
/1, /2, /4, /8
CH0CAPPS
C[1:0]
CHCTL0
CH0EN
CHCTL2
IC0
Channel controller
The GPTM has four independent channels which can be used as capture inputs or compare
match outputs.
When used in the input capture mode, the counter value is captured into the TIMER0_CHxCV
shadow register first and then transferred into the TIMER0_CHxCV preload register when the
capture event occurs.
When used in the compare match output mode, the contents of the TIMER0_CHxCV preload
register is copied into the associated shadow register; the counter value is then compared
with the register value.
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Figure 9-24. Capture/compare channel 0 main circuit
APB BUS
MCU-peripheral interface
Capture/compare preload register
Capture/compare shadow
register
Counter
CH0VAL
CH0MS[0]
CH0MS[1]
CH0CAPPSC
CH0EN
CH0G
TIMER_SWEVG
CH0VAL
CH0MS[0]
CH0MS[1]
CH0COMSEN
UPE
CNT>CH0VAL
CNT=CH0VAL
Output stage
The TIMER0 has four channels for compare match, single pulse or PWM output function.
Figure 9-25. Output stage of capture/compare channel (channel 0 to 2)
Output mode controller
CNT>CH0VAL
CNT=CH0VAL
CH0COMCTL
[2:0]
CHCTL0
ETI
0
1
CH0NP
CHCTL2
11
CH0MS[ 1:0 ]
CHCTL0
10
x0
Dead-time
generator
DTCFG
[7:0]
CCHP
x0
CH0MS[ 1:0 ]
CHCTL0
10
11
0
1
CH0P
CHCTL2
Output
enable
circuit
CHx_O
Output
enable
circuit
CHx_ON
CH0NEN
CHCTL2
POEN
CCHP ROS IOS
CH0EN
CHCTL2
CH0COM
CEN
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Figure 9-26. Output stage of capture/compare channel (channel 3)
Output mode controller
CNT>CH3VAL
CNT=CH3VAL
CH3COMCTL[
2:0]
CHCTL0
ETI
0
1
CH3P
CHCTL2
Output enable
circuit
CHx_O
CHxEN
CHCTL2
POE
CCHP ROS
CH3COM
CEN
Input Capture Mode
When the channel is used as a capture input, the counter value is captured into the Channel
Capture/Compare Register (TIMER0_CHxCV) when an effective input signal transition
occurs. Once the capture event occurs, the CHxIF flag in the TIMER0_INTF register is set. If
the CHxIF bit is already set, i.e., the flag has not yet been cleared by software, and another
capture event on this channel occurs, the corresponding channel Over-Capture flag, named
CHxOF, will be set.Once the capture event occurs, a DMA request is generated depending
on the CHxDEN bit and an interrupt is generated depending on the CHxIE bit. The fllowing
step maybe used to implement input capture mode:
Select input signal by set CHxMS bits in the channel control register (TIMER0_CHCTLx).
Add input filter to input signal by set CHxCAPFLT bitst in the the channel control register
(TIMER0_CHCTLx).
Select input capture edge (rising or falling) by set CHxP/CHxNP bit in the channel control
register 2 (TIMER0_CHCTL2).
If input signal need prescaler, set CHxCAPPSC bits in the the channel control register
(TIMER0_CHCTLx).
If need interrupt, set CHxIE bit in DMA and interrupt enable register
(TIMER0_DMAINTEN) to 1.
If need DMA request, set CHxDEN bit in DMA and interrupt enable register
(TIMER0_DMAINTEN) to 1.
Enable the channel by set CHxEN bit in the channel control register 2 (TIMER0_CHCTL2)
to 1.
After configure this registers, the input capture event on this channel may occurs at the
corresponding edge. And the counter value is captured into the Channel Capture/Compare
Register (TIMER0_CHxCV). An interrupt generated if CHxIE bit set. A DMA request
generated if CHxDEN set.
The input capture mode can be also used for pulse width measurement from signals on the
TIMER0_CHx pins (CIx). For example, PWM signal connect to CI0 input. Select channel 0
capture signal to CI0 by setting CH0MS to 01 in the channel control register
(TIMER0_CHCTL0) and set capture on rising edge. Select channel 1 capture signal to CI0
by setting CH1MS to 10 in the channel control register (TIMER0_CHCTL0) and set capture
on falling edge. The counter set to restart mode and restart on channel 0 rising edge. Then
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the TIMER0_CH0CV can measure the PWM period and the TIMER0_CH1CV can measure
the PWM duty.
Output Compare Mode/PWM Mode
When the channel is used as an output mode by setting the CHxMS in the the channel control
register (TIMER0_CHCTLx) to 00, the channel outputs waveform according to the
CHxCOMCTL bits in the the the channel control register (TIMER0_CHCTLx), and the
comparision between the counter and TIMER0_CHxCV registers. When the comparision
equals, the CHxIF flag in the Interrupt flag registers (TIMER0_INTF) set to 1. A DMA request
is generated depending on the CHxDEN bit and an interrupt is generated depending on the
CHxIE bit.
In output mode, the channel can outputs active level by set the CHxCOMCTL to 101, and
outputs inactive level by set the CHxCOMCTL bits to 100.
In ouput mode, the channel output set to active level when the comparision between the
counter and TIMER0_CHxCV registers match, by set the CHxCOMCTL to 001. The channel
output set to inactive level when the comparision between the counter and TIMER0_CHxCV
registers match, by set the CHxCOMCTL to 010.
In output compare toggle mode (by set the CHxCOMCTL to 011), the channel output toggles
when the comparision between the counter and TIMER0_CHxCV registers match.
Figure 9-27. Output compare toggle mode, toggle on CH0_O
CNT_REG
O0CPRE=CH0_O
003A0039
CH0VAL
003B B200 B201
003A B201
Match detected on CH0VAL
Interrupt generated if enabled
Write B201h in the CH0VAL
register
In the output PWM mode (by setting the CHxCOMCTL bits to 110 (PWM mode 0) or to 111
(PWM mode 1)), the channel can outputs PWM waveform according to the TIMER0_CAR
registers and TIMER0_CHxCV registers.
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Figure 9-28. Output compare PWM mode 0 on CH0_O, upcounting mode
CNT_REG
O0CPRE=CH0_O
003A0039
CH0VAL
003B 100 0
003A
Match detected on CH0VAL
Interrupt generated if enabled
Figure 9-29. Output compare PWM mode 0 on CH0_O, center-aligned counting mode
CNT_REG
O0CPRE=CH0_O
003A0039
CH0VAL
003B 0100 00FF
003A
Match detected on CH0VAL
Interrupt generated if enabled
00FE 003B 003A 0039
Channel Output Reference Signal
When the TIMER0 is used in the compare match output mode, the OxCPRE signal (Channel
x Output Reference signal) is defined by setting the CHxCOMCTL bits. The OxCPRE signal
has several types of output function. These include, keeping the original level by setting the
CHxCOMCTL field to 0x00, set to 1 by setting the CHxCOMCTL field to 0x01, set to 0 by
setting the CHxCOMCTL field to 0x02 or signal toggle by setting the CHxCOMCTL field to
0x03 when the counter value matches the content of the TIMER0_CHxCV register.
The PWM mode 0 and PWM mode 1 outputs are also another kind of OxCPRE output which
is setup by setting the CHxCOMCTL field to 0x06/0x07. In these modes, the OxCPRE signal
level is changed according to the counting direction and the relationship between the counter
value and the TIMER0_CHxCV content. With regard to a more detailed description refer to
the relative bit definition.
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Another special function of the OxCPRE signal is a forced output which can be achieved by
setting the CHxCOMCTL field to 0x04/0x05. Here the output can be forced to an
inactive/active level irrespective of the comparison condition between the counter and the
TIMER0_CHxCV values.
The OxCPRE signal can be forced to 0 when the ETIF signal is derived from the external
TIMER0_ ETI pin and when it is set to a high level by setting the CHxCOMCEN bit to 1 in the
TIMER0_CHCTL0 register. The OxCPRE signal will not return to its active level until the next
update event occurs.
Outputs Complementary and Dead-time
The TIMER0 can output two complementary signals. The complementary signals CHx_O and
CHx_ON are activated by a combination of several control bits: the CHxEN and CHxNEN bits
in the TIMER0_CHCTL2 register and the POEN, ISOx, ISOxN, IOS and ROS bits in the
TIMER0_CCHP and TIMER0_CTL1 registers.The outputs polarity are determined by CHxP
and CHxNP bits in the TIMER0_CHCTL2 register.
If CHxEN, CHxNEN and POEN bits are 1, dead-time should insertion. The rising edge of
CHx_O output is delayed relative to the rising edge of OxCPRE and the rising edge of
CHx_ON output is delayed relative to the falling edge of OxCPRE.The delay value is a 8-bit
dead-time counter determined by DTCFG field in TIMER0_CCHP register.If the delay value
is greater than the width of the active output (CHx_O or CHx_ON) then the corresponding
pulse is not generated.
Figure 9-30. Complementary output with dead-time insertion.
OxCPRE
CHx_O
CHx_ON
Dead_time
Dead_time
Figure 9-31. Dead-time waveforms with delay greater than the negative pulse
OxCPRE
CHx_O
CHx_ON
Dead_time
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Figure 9-32. Dead-time waveforms with delay greater than the positive pulse
OxCPRE
CHx_ON
CHx_O
Dead_time
Break function
In this function, the output CHx_O and CHx_ON are controlled by the POEN, IOS and ROS
bits in the TIMER0_CCHP register, ISOx and ISOxN bits in the TIMER0_CTL1 register and
cannot be set both to active level when break occurs. The break sources are input break pin
or HXTAL stack event by Clock Monitor (CKM) in RCU. The break function enabled by setting
the BRKEN bit in the TIMER0_CCHP register. The break input polarity is setting by the BRKP
bit in TIMER0_CCHP.
When a break occurs, the POEN bit is cleared asynchronously, the output CHx_O and
CHx_ON are driven with the level programmed in the ISOx bit in the TIMER0_CTL1 register
as soon as POEN is 0. If IOS is 0 then the timer releases the enable output else the enable
output remains high. The complementary outputs are first put in reset state, and then the
dead-time generator is reactivated in order to drive the outputs with the level programmed in
the ISOx and ISOxN bits after a dead-time.
When a break occurs, the BRKIF bit in the TIMER0_INTF register is set. If BRKIE is 1, an
interrupt generated.
Figure 9-33. Output behavior in response to a break（The break input is acting on high
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level）
OxCPRE
CHx_O
CHx_O
CHx_O
CHx_O
CHx_O
CHx_ON
CHx_O
CHx_ON
CHx_O
CHx_ON
CHx_O
CHx_ON
CHx_O
CHx_ON
Break_In
CHx_ON not implemented CHxP=0,ISOx=1
CHx_ON not implemented CHxP=0,ISOx=0
CHx_ON not implemented CHxP=1,ISOx=1
CHxEN=1, CHxP=0,ISOx=0,CHxNEN=1,CHxNP=0,ISOxN=1
CHxEN=1, CHxP=0,ISOx=1,CHxNEN=1,CHxNP=1,ISOxN=1
CHxEN=1, CHxP=0,ISOx=0,CHxNEN=0,CHxNP=0,ISOxN=1
CHxEN=1, CHxP=0,ISOx=1,CHxNEN=0,CHxNP=0,ISOxN=0
CHxEN=1, CHxP=0,CHxNEN=0,CHxNP=0,ISOx=0,ISOxN=0 or ISOx=0,ISOxN=1
delay
delaydelaydelay
delay delay
CHx_ON not implemented CHxP=0,ISOx=1
Single Pulse Mode
Once the timer is set to operate in the single pulse mode, it is not necessary to set the timer
enable bit CEN in the TIMER0_CTL0 register to 1 to enable the counter. The trigger to
generate a pulse can be sourced from the trigger signals edge or by setting the CEN bit to 1
using software. Setting the CEN bit to 1 or a trigger from the trigger signals edge can generate
a pulse and then keep the CEN bit at a high state until the update event occurs or the CEN
bit is written to 0 by software. If the CEN bit is cleared to 0 using software, the counter will be
stopped and its value held. If the CEN bit is automatically cleared to 0 by a hardware update
event, the counter will be reinitialized.
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In the Single Pulse mode, the trigger active edge which sets the CEN bit to 1 will enable the
counter. However, there exist several clock delays to perform the comparison result between
the counter value and the TIMER0_CHxCV value. In order to reduce the delay to a minimum
value, the user can set the CHxOFE bit in each TIMER0_CHCTL0 register. After a trigger
rising occurs in the single pulse mode, the OxCPRE signal will immediately be forced to the
state which the OxCPRE signal will change to, as the compare match event occurs without
taking the comparison result into account. The CHxOFE bit is available only when the output
channel is configured to operate in the PWM0 or PWM1 output mode and the trigger source
is derived from the trigger signal.
Figure 9-34. Single pulse mode
O0CPRE
CH0_O
CI1
CH0VAL
CARL
T
TIMER_CNT
Quadrature Decoder
The Quadrature Decoder function uses two quadrature inputs CI0 and CI1 derived from the
TIMER0_CH0 and TIMER0_CH1 pins respectively to interact to generate the counter value.
The DIR bit is modified by hardware automatically during each input source transition. The
input source can be either CI0 only, CI1 only or both CI0 and CI1, the selection made by
setting the SMC field to 0x01, 0x02 or 0x03. The mechanism for changing the counter
direction is shown in the following table. The Quadrature decoder can be regarded as an
external clock with a directional selection. This means that the counter counts continuously
in the interval between 0 and the counter-reload value. Therefore, users must configure the
TIMER0_CAR register before the counter starts to count.
Table 9-1. Counting direction versus encoder signals
Counting
mode
Level
CI0FE0
CI1FE1
Rising
Falling
Rising
Falling
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CI0 only
counting
CI1FE=High
Down
Up
-
-
CI1FE=Low
Up
Down
-
-
CI1 only
counting
CI0FE=High
-
-
Up
Down
CI0FE=Low
-
-
Down
Up
CI0 and CI1
counting
CI1FE=High
Down
Up
X
X
CI1FE=Low
Up
Down
X
X
CI0FE=High
X
X
Up
Down
CI0FE=Low
X
X
Down
Up
Note: "-" means "no counting"; "X" means impossible.
Figure 9-35. Example of counter operation in encoder interface mode
CI0
CI1
UP downCount
Figure 9-36. Example of encoder interface mode with CI0FE0 polarity inverted
CI0
CI1
UPdownCount
Slave Controller
The TIMER0 can be synchronized with an external trigger in several modes including the
Restart mode, the Pause mode and the event mode which is selected by the SMC field in the
TIMER0_SMCFG register. The trigger input of these modes can be selected by the TRGS
field in the TIMERx_SMCFG register, below to CI0 signal as an example. The operation
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modes in the Slave Controller are described in the accompanying sections.
Restart mode
The counter and its prescaler can be reinitialized in response to a rising edge of the CI0 signal.
When a CI0 rising edge occurs, the update event software generation bit named UPG will
automatically be asserted by hardware and the trigger event flag will also be set. Then the
counter and prescaler will be reinitialized. Although the UPG bit is set to 1 by hardware, the
update event does not really occur. It depends upon whether the update event disable control
bit UPDIS is set to 1 or not. If UPDIS is set to 1 to disable the update event to occur, there
will no update event will be generated, however the counter and prescaler are still reinitialized
when the CI0 rising edge occurs. If the UPDIS bit in the TIMER0_CTL0 register is cleared to
enable the update event to occur, an update event will be generated together with the CI0
rising edge, then all the preloaded registers will be updated.
Figure 9-37. Control circuit in restart mode
CNT_CLK
CNT_REG 60 61 62 63 00 01 02 03 04 00 01 02 03 04
UPG
TRGIF
CI0
Pause mode
In the Pause Mode, the selected CI0 input signal level is used to control the counter start/stop
operation. The counter starts to count when the selected CI0 signal is at a high level and
stops counting when the CI0 signal is changed to a low level, here the counter will maintain
its present value and will not be reset.
Figure 9-38. Control circuit in pause mode
CNT_CLK
CNT_REG 52 53 54 55 57 58 59
CI0
TRGIF
CEN
56
Event mode
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After the counter is disabled to count, the counter can resume counting when a CI0 rising
edge signal occurs. When a CI0 rising edge occurs, the counter will start to count from the
current value in the counter. Note that the CI0 signal is only used to enable the counter to
resume counting and has no effect on controlling the counter to stop counting.
Figure 9-39. Control circuit in event mode
CNT_CLK
CNT_REG
CI0
TRGIF
56 57 58 59 5A 5B 5C 5D 5E 5F
CEN
Timer Interconnection
The timers can be internally connected together for timer chaining or synchronization. This
can be implemented by configuring one timer to operate in the Master mode while configuring
another timer to be in the Slave mode. The following figures present several examples of
trigger selection for the master and slave modes.
Figure below shows the TIMER0 trigger selection when it is configured in slave mode.
Figure 9-40. TIMER0 Master/Slave mode timer example
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TIMER0
TIMER 14
Prescaler Counter
Master
mode
control
TIMER 1
Prescaler Counter
Master
mode
control
TIMER 2
Prescaler Counter
Master
mode
control
Trigger
selection
ITI0
ITI1
ITI2
CI0F_ED
CI0FE0
CI1FE1
ETIF
TRGS
trigger
selection
Slave mode
control Prescaler Counter
TRGO
TRGO
TRGO
Other interconnection examples:
TIMER1 as prescaler for TIMER0
We configure TIMER1 as a prescaler for TIMER0. Refer to Figure below for connections. Do
as follow:
1. Configure TIMER1 in master mode and select its Update Event (UPE) as trigger output
(MMC=010 in the TIMER1_CTL1 register). Then TIMER1 drives a periodic signal on each
counter overflow.
2. Configure the TIMER1 period (TIMER1_CAR registers).
3. Select the TIMER0 input trigger source from TIMER1 (TRGS=001 in the
TIMER0_SMCFG register).
4. Configure TIMER0 in external clock mode 1 (SMC=111 in TIMER0_SMCFG register).
5. Start TIMER0 by writing ‘1 in the CEN bit (TIMER0_CTL0 register).
6. Start TIMER1 by writing ‘1 in the CEN bit (TIMER1_CTL0 register).
Start TIMER0 with TIMER1’s Enable/Update signal
First, we enable TIMER0 with the enable out of TIMER1. Refer to Figure below. TIMER0
starts counting from its current value on the divided internal clock after trigger by TIMER1
enable output.
When TIMER0 receives the trigger signal its CEN bit is automatically set and the counter
counts until we disable TIMER0. Both counter clock frequencies are divided by 3 by the
prescaler compared to TIMER_CK (fCNT_CLK = fTIMER_CK /3). Do as follow:
1. Configure TIMER1 master mode to send its enable signal as trigger output(MMC=001 in
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the TIMER1_CTL1 register)
2. Configure TIMER0 to select the input trigger from TIMER1 (TRGS=001 in the
TIMER0_SMCFG register).
3. Configure TIMER0 in event mode (SMC=110 in TIMER0_SMCFG register).
4. Start TIMER1 by writing 1 in the CEN bit (TIMER1_CTL0 register).
Figure 9-41. Triggering TIMER0 with Enable of TIMER1
TIMER_CK
TIMER1_CNT_REG
TIMER0_CNT_REG
TIMER1_CEN
61 62 63
11 12 13
TIMER0_TRGIF
14
In this example, we also can use update Event as trigger source instead of enable signal.
Refer to figure below. Do as follow:
1. Configure TIMER1 in master mode and send its Update Event (UPE) as trigger output
(MMC=010 in the TIMER1_CTL1 register).
2. Configure the TIMER1 period (TIMER1_CAR registers).
3. Configure TIMER0 to get the input trigger from TIMER1 (TRGS=001 in the
TIMER0_SMCFG register).
4. Configure TIMER0 in event mode (SMC=110 in TIMER0_SMCFG register).
5. Start TIMER1 by writing ‘1 in the CEN bit (TIMER1_CTL0 register).
Figure 9-42. Triggering TIMER0 with update of TIMER1
TIMER_CK
TIMER1_CNT_REG
TIMER0_CNT_REG
TIMER1_UPE
62
11 12
TIMER0_TRGIF
63 00 01 02
TIMER0_CEN
13 14
Enable TIMER0 count with TIMER1’s enable/O0CPRE signal
In this example, we control the enable of TIMER0 with the enable output of TIMER1 .Refer to
figure below. TIMER0 counts on the divided internal clock only when TIMER1 is enable. Both
counter clock frequencies are divided by 3 by the prescaler compared to TIMER_CK (fCNT_CLK
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= fTIMER_CK /3). Do as follow:
1. Configure TIMER1 input master mode and Output enable signal as trigger output
(MMC=001 in the TIMER1_CTL1 register).
2. Configure TIMER0 to get the input trigger from TIMER1 (TRGS=001 in the
TIMER0_SMCFG register).
3. Configure TIMER0 in pause mode (SMC=101 in TIMER0_SMCFG register).
4. Enable TIMER0 by writing ‘1 in the CEN bit (TIMER0_CTL0 register)
5. Start TIMER1 by writing ‘1 in the CEN bit (TIMER1_CTL0 register).
6. Stop TIMER1 by writing ‘0 in the CEN bit (TIMER1_CTL0 register).
Figure 9-43. Gating TIMER0 with enable of TIMER1
TIMER_CK
TIMER1_CNT_REG
TIMER0_CNT_REG
TIMER1_CEN
61 62 63
11 12 13
TIMER0_TRGIF
In this example, we also can use OxCPRE as trigger source instead of enable signal output.
Do as follow:
1. Configure TIMER1 in master mode and Output Compare 1 Reference (O0CPRE) signal
as trigger output (MMS=100 in the TIMER1_CTL1 register).
2. Configure the TIMER1 O0CPRE waveform (TIMER1_ CHCTL0 register).
3. Configure TIMER0 to get the input trigger from TIMER1 (TRGS=001 in the
TIMER0_SMCFG register).
4. Configure TIMER0 in pause mode (SMC=101 in TIMER0_SMCFG register).
5. Enable TIMER0 by writing ‘1 in the CEN bit (TIMER0_CTL0 register).
6. Start TIMER1 by writing ‘1 in the CEN bit (TIMER1_CTL0 register).
Figure 9-44. Gating TIMER0 with O0CPREof TIMER1
TIMER_CK
TIMER1_CNT_REG
TIMER0_TRGIF
TIMER0_CNT_REG
60
TIMER1_O0CPRE
61 62 63 00 01
11 12 13 14
Using an external trigger to start 2 timers synchronously
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We configure the start of TIMER0 is triggered by the enable of TIMER1, and TIMER1 is
triggered by its CI0 input rises edge. To ensure 2 timers start synchronously, TIMER1 must
be configured in Master/Slave mode. Do as follow:
1. Configure TIMER1 slave mode to get the input trigger from CI0 (TRGS=100 in the
TIMER1_SMCFG register).
2. Configure TIMER1 in event mode (SMC=110 in the TIMER1_SMCFG register).
3. Configure the TIMER1 in Master/Slave mode by writing MSM=1 (TIMER1_SMCFG
register).
4. Configure TIMER0 to get the input trigger from TIMER1 (TRGS=001 in the
TIMER0_SMCFG register).
5. Configure TIMER0 in event mode (SMC=110 in the TIMER1_SMCFG register).
When a rising edge occurs on TIMER1’s CI0, two timer counters starts counting
synchronously on the internal clock and both TRGIF flags are set.
Figure 9-45. Triggering TIMER0 and TIMER1 with TIMER1’s CI0 input
TIMER_CK
TIMER1_CNT_REG
TIMER0_CNT_REG
TIMER1_CI0
00 01
TIMER1_CEN
TIMER1_CK
02 03
00 01 02 03
TIMER0_CK
TIMER1_TRGIF
TIMER0_CEN
TIMER0_TRGIF
Timer debug mode
When the Cortex™-M3 halted, and the DBG_TIMERx_STOP configuration bit in DBG module
set to 1, the TIMERx counter stops.
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9.1.4. TIMER0 registers
Control register 0 (TIMERx_CTL0)
Address offset: 0x00
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
CKDIV[1:0]
ARSE
CAM[1:0]
DIR
SPM
UPS
UPDIS
CEN
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
15:10
Reserved
Must be kept at reset value
9:8
CKDIV[1:0]
Clock division
The CKDIV bits can be configured by software to specify division ratio between the
timer clock (TIMER_CK) and the dead-time and sampling clock (DTS), which is
used by the dead-time generators and the digital filters.
00: fDTS= fTIMER_CK
01: fDTS= fTIMER_CK /2
10: fDTS= fTIMER_CK /4
11: Reserved
7
ARSE
Auto-reload shadow enable
0: The shadow register for TIMERx_CAR register is disabled
1: The shadow register TIMERx_CAR register is enabled
6:5
CAM[1:0]
Counter aligns mode selection
00: No center-aligned mode (edge-aligned mode). The direction of the counter is
specified by the DIR bit.
01: Center-aligned and counting down assert mode. The counter counts up and
down alternatively. Output compare interrupt flags of channels, which are
configured in output mode (CHxMS=00 in TIMERx_CHCTLx register), are set only
when the counter is counting down.
10: Center-aligned and counting up assert mode. The counter counts up and down
alternatively. Output compare interrupt flags of channels, which are configured in
output mode (CHxMS=00 in TIMERx_CHCTLx register), are set only when the
counter is counting up.
11: Center-aligned and counting up/down assert mode. The counter counts up and
down alternatively. Output compare interrupt flags of channels, which are
configured in output mode (CHxMS=00 in TIMERx_CHCTLx register), are set only
when the counter is counting both up and down.
After the counter is enabled, cannot be switched from 0x00 to non 0x00.
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4
DIR
Direction
0: Count up
1: Count down
This bit is read only when the timer is configured in Center-aligned mode or
Encoder mode.
3
SPM
Single pulse mode.
0: Counter continues after update event.
1: The CEN is cleared by hardware and the counter stops at next update event.
2
UPS
Update source
This bit is used to select the update event sources by software.
0: Any of the following events generate an update interrupt or DMA request:
– The UPG bit is set
– The counter generates an overflow or underflow event
– The slave mode controller generates an update event.
1: Only counter overflow/underflow generates an update interrupt or DMA request.
1
UPDIS
Update disable.
This bit is used to enable or disable the update event generation.
0: update event enable. The update event is generate and the buffered registers are
loaded with their preloaded values when one of the following events occurs:
– The UPG bit is set
– The counter generates an overflow or underflow event
– The slave mode controller generates an update event.
1: update event disable. The buffered registers keep their value, while the counter
and the prescaler are reinitialized if the UPG bit is set or if the slave mode controller
generates a hardware reset event.
0
CEN
Counter enable
0: Counter disable
1: Counter enable
The CEN bit must be set by software when timer works in external clock, pause
mode and encoder mode. While in event mode, the hardware can set the CEN bit
automatically.
Control register 1 (TIMERx_CTL1)
Address offset: 0x04
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Res.
ISO3
ISO2N
ISO2
ISO1N
ISO1
ISO0N
ISO0
TI0S
MMC[2:0]
DMAS
CCUC
Res.
CCSE
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
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Bits
Fields
Descriptions
15
Reserved
Must be kept at reset value
14
ISO3
Idle state of channel 3 output
Refer to ISO0 bit
13
ISO2N
Idle state of channel 2 complementary output
Refer to ISO0N bit
12
ISO2
Idle state of channel 2 output
Refer to ISO0 bit
11
ISO1N
Idle state of channel 1 complementary output
Refer to ISO0N bit
10
ISO1
Idle state of channel 1 output
Refer to ISO0 bit
9
ISO0N
Idle state of channel 0 complementary output
0: When POEN bit is reset, CH0_ON is set low.
1: When POEN bit is reset, CH0_ON is set high
This bit can be modified only when PROT[1:0] bits in TIMERx_CCHP register is 00.
8
ISO0
Idle state of channel 0 output
0: When POEN bit is reset, CH0_O is set low.
1: When POEN bit is reset, CH0_O is set high
The CH0_O output changes after a dead-time if CH0_ON is implemented. This bit
can be modified only when PROT[1:0] bits in TIMERx_CCHP register is 00.
7
TI0S
Channel 0 trigger input selection
0: The TIMERx_CH0 pin input is selected as channel 0 trigger input.
1: The result of combinational XOR of TIMERx_CH0, CH1 and CH2 pins is selected
as channel 0 trigger input.
6:4
MMC[2:0]
Master mode control
These bits control the selection of TRGO signal, which is sent in master mode to
slave timers for synchronization function.
000: Reset. When the UPG bit in the TIMERx_SWEVG register is set or a reset is
generated by the slave mode controller, a TRGO pulse occurs. And in the latter
case, the signal on TRGO is delayed compared to the actual reset.
001: Enable. This mode is useful to start several timers at the same time or to
control a window in which a slave timer is enabled. In this mode the master mode
controller selects the counter enable signal as TRGO. The counter enable signal is
set when CEN control bit is set or the trigger input in pause mode is high. There is a
delay between the trigger input in pause mode and the TRGO output, except if the
master-slave mode is selected.
010: Update. In this mode the master mode controller selects the update event as
TRGO.
GD32F1x0 User Manual
183
011: Capture/compare pulse.In this mode the master mode controller generates a
TRGO pulse when a capture or a compare match occurred.
100: Compare.In this mode the master mode controller selects the O0CPRE signal
is used as TRGO
101: Compare.In this mode the master mode controller selects the O1CPRE signal
is used as TRGO
110: Compare.In this mode the master mode controller selects the O2CPRE signal
is used as TRGO
111: Compare.In this mode the master mode controller selects the O3CPRE signal
is used as TRGO
3
DMAS
DMA request source selection
0: DMA request of channel x is sent when capture/compare event occurs.
1: DMA request of channel x is sent when update event occurs.
2
CCUC
Commutation control shadow register update control
When the commutation control shadow registers (for CHxEN, CHxNEN and
CHxCOMCTL bits) are enabled (CCSE=1), this bit control when these shadow
registers update.
0: The shadow registers update by when CMTG bit is set.
1: The shadow registers update by when CMTG bit is set or a rising edge of TRGI
occurs.
When a channel does not have a complementary output, this bit has no effect.
1
Reserved
Must be kept at reset value.
0
CCSE
Commutation control shadow register enable
0: The shadow registers for CHxEN, CHxNEN and CHxCOMCTL bits are disabled.
1: The shadow registers for CHxEN, CHxNEN and CHxCOMCTL bits are enabled.
After these bits have been written, they are updated based when commutation
event coming.
When a channel does not have a complementary output, this bit has no effect.
Slave mode configuration register (TIMERx_SMCFG)
Address offset: 0x08
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
ETP
SMC1
ETPSC[1:0]
ETFC[3:0]
MSM
TRGS[2:0]
OCRC
SMC[2:0]
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
15
ETP
External trigger polarity
This bit specifies the polarity of ETI signal
GD32F1x0 User Manual
184
0: ETI is active at high level or rising edge.
1: ETI is active at low level or falling edge.
14
SMC1
Part of SMC for enable External clock mode1
In external clock mode 1, the counter is clocked by any active edge on the ETIF
signal.
0: External clock mode 1 disabled
1: External clock mode 1 enabled.
Setting the SMC1 bit has the same effect as selecting external clock mode 0 with
TRGI connected to ETIF (SMC=111 and TRGS =111).
It is possible to simultaneously use external clock mode 1 with the reset mode,
pause mode or event mode. But the TRGS bits must not be 111 in this case.
The external clock input will be ETIF if external clock mode 1 and external clock
mode 1 are enabled at the same time.
13:12
ETPSC[1:0]
External trigger prescaler
The frequency of external trigger signal ETI must not be at higher than 1/4 of
TIMERx_CK frequency. When the external trigger signal is a fast clocks, the
prescaler can be enabled to reduce ETI frequency.
00: Prescaler disable
01: ETI frequency will be divided by 2
10: ETI frequency will be divided by 4
11: ETI frequency will be divided by 8
11:8
ETFC[3:0]
External trigger filter control
An event counter is used in the digital filter, in which a transition on the output
occurs after N input events. This bit-field specifies the frequency used to sample
ETI signal and the length of the digital filter applied to ETI.
0000: Filter disalble. fSAMP= fDTS, N=1.
0001: fSAMP= fTIMER_CK, N=2.
0010: fSAMP= fTIMER_CK, N=4.
0011: fSAMP= fTIMER_CK, N=8.
0100: fSAMP=fDTS/2, N=6.
0101: fSAMP=fDTS/2, N=8.
0110: fSAMP=fDTS/4, N=6.
0111: fSAMP=fDTS/4, N=8.
1000: fSAMP=fDTS/8, N=6.
1001: fSAMP=fDTS/8, N=8.
1010: fSAMP=fDTS/16, N=5.
1011: fSAMP=fDTS/16, N=6.
1100: fSAMP=fDTS/16, N=8.
1101: fSAMP=fDTS/32, N=5.
1110: fSAMP=fDTS/32, N=6.
1111: fSAMP=fDTS/32, N=8.
7
MSM
Master-slave mode
GD32F1x0 User Manual
185
The effect of an event on the trigger input is delayed in this mode to allow a perfect
synchronization between the current timer and its slaves through TRGO. If we want
to synchronize several timers on a single external event, this mode can be used.
0: Master-slave mode disable
1: Master-slave mode enable
6:4
TRGS[2:0]
Trigger selection
This bit-field specifies which signal is selected as the trigger input, which is used to
synchronize the counter.
000: Internal trigger input 0 (ITI0) TIMER14
001: Internal trigger input 1 (ITI1) TIMER1
010: Internal trigger input 2 (ITI2) TIMER2
011: Internal trigger input 3 (ITI3) Res.
100: CI0 edge flag (CI0F_ED)
101: channel 0 input Filtered output (CI0FE0)
110: channel 1 input Filtered output (CI1FE1)
111: External trigger input filter output (ETIF)
These bits must not be changed when slave mode is enabled.
3
OCRC
OCPRE clear source selection
0: OCPRE_CLR_INT is connected to the OCPRE_CLR input
1: OCPRE_CLR_INT is connected to ETIF
2:0
SMC[2:0]
Slave mode control
000: Disable mode.The prescaler is clocked directly by the internal clock when CEN
bit is set high.
001: Quadrature decoder mode 0.The counter counts on CI1FE1 edge, while the
direction depends on CI0FE0 level.
010: Quadrature decoder mode 1.The counter counts on CI0FE0 edge, while the
direction depends on CI1FE1 level.
011: Quadrature decoder mode 2.The counter counts on both CI0FE0 and CI1FE1
edge, while the direction depends on each other.
100: Restart Mode. The counter is reinitialized and the shadow registers are
updated on the rising edge of the selected trigger input.
101: Pause Mode. The trigger input enables the counter clock when it is high and
disables the counter when it is low.
110: Event Mode. A rising edge of the trigger input enables the counter. The
counter cannot be disabled by the slave mode controller.
111: External Clock Mode 0. The counter counts on the rising edges of the selected
trigger.
Because CI0F_ED outputs 1 pulse for each transition on CI0F, and the pause mode
checks the level of the trigger signal, when CI0F_ED is selected as the trigger input,
the pause mode must not be used.
GD32F1x0 User Manual
186
DMA and interrupt enable register (TIMERx_DMAINTEN)
Address offset: 0x0C
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Res
TRGDEN
CMTDEN
CH3DEN
CH2DEN
CH1DEN
CH0DEN
UPDEN
BRKIE
TRGIE
CMTIE
CH3IE
CH2IE
CH1IE
CH0IE
UPIE
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
15
Reserved
Must be kept at reset value.
14
TRGDEN
Trigger DMA request enable
0: Trigger DMA request disabled
1: Trigger DMA request enabled
13
CMTDEN
CMT DMA request enable
0: CMT DMA request disabled
1: CMT DMA request enabled
12
CH3DEN
Channel 3 Capture/Compare DMA request enable
0: Channel 3 Capture/Compare DMA request disabled
1: Channel 3 Capture/Compare DMA request enabled
11
CH2DEN
Channel 2 Capture/Compare DMA request enable
0: Channel 2 Capture/Compare DMA request disabled
1: Channel 2 Capture/Compare DMA request enabled
10
CH1DEN
Channel 1 Capture/Compare DMA request enable
0: Channel 1 Capture/Compare DMA request disabled
1: Channel 1 Capture/Compare DMA request enabled
9
CH0DEN
Channel 0 Capture/Compare DMA request enable
0: Channel 0 Capture/Compare DMA request disabled
1: Channel 0 Capture/Compare DMA request enabled
8
UPDEN
Update DMA request enable
0: Update DMA request disabled
1: Update DMA request enabled
7
BRKIE
Break interrupt enable
0: Break interrupt disabled
1: Break interrupt enabled
6
TRGIE
Trigger interrupt enable
0: Trigger interrupt disabled
1: Trigger interrupt enabled
GD32F1x0 User Manual
187
5
CMTIE
CMT interrupt enable
0: CMT interrupt disabled
1: CMT interrupt enabled
4
CH3IE
Channel 3 Capture/Compare interrupt enable
0: Channel 3 Capture/Compare interrupt disabled
1: Channel 3 Capture/Compare interrupt enabled
3
CH2IE
Channel 2 Capture/Compare interrupt enable
0: Channel 2 Capture/Compare interrupt disabled
1: Channel 2 Capture/Compare interrupt enabled
2
CH1IE
Channel 1 Capture/Compare interrupt enable
0: Channel 1 Capture/Compare interrupt disabled
1: Channel 1 Capture/Compare interrupt enabled
1
CH0IE
Channel 0 Capture/Compare interrupt enable
0: Channel 0 Capture/Compare interrupt disabled
1: Channel 0 Capture/Compare interrupt enabled
0
UPIE
Update interrupt enable
0: Update interrupt disabled
1: Update interrupt enabled
Interrupt flag register (TIMERx_INTF)
Address offset: 0x10
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
CH3OF
CH2OF
CH1OF
CH0OF
Res.
BRKIF
TRGIF
CMTIF
CH3IF
CH2IF
CH1IF
CH0IF
UPIF
rc_w0
rc_w0
rc_w0
rc_w0
.
rc_w0
rc_w0
rc_w0
rc_w0
rc_w0
rc_w0
rc_w0
rc_w0
Bits
Fields
Descriptions
15:13
Reserved
Must be kept at reset value.
12
CH3OF
Channel 3 Capture overflow flag
Refer to CH0OF description
11
CH2OF
Channel 2 Capture overflow flag
Refer to CH0OF description
10
CH1OF
Channel 1 Capture overflow flag
Refer to CH0OF description
9
CH0OF
Channel 0 Capture overflow flag
When channel 0 is configured in input mode, this flag is set by hardware when a
GD32F1x0 User Manual
188
capture event occurs while CH0IF flag has already been set. This flag is cleared by
software.
0: No Capture overflow interrupt occurred
1: Capture overflow interrupt occurred
8
Reserved
Must be kept at reset value.
7
BRKIF
Break interrupt flag
This flag is set by hardware when the break input goes active, and cleared by
software if the break input is not active.
0: No active level break has been detected.
1: An active level has been detected.
6
TRGIF
Trigger interrupt flag
This flag is set by hardware on trigger event and cleared by software. When the
slave mode controller is enabled in all modes but pause mode, an active edge on
TRGI input generates a trigger event. When the slave mode controller is enabled in
pause mode both edges on TRGI input generates a trigger event.
0: No trigger event occurred.
1: Trigger interrupt occurred.
5
CMTIF
Channel commutation interrupt flag
This flag is set by hardware when channel’s commutation event occurs, and cleared
by software
0: No channel commutation interrupt occurred
1: Channel commutation interrupt occurred
4
CH3IF
Channel 3‘s Capture/Compare interrupt enable
Refer to CH0IF description
3
CH2IF
Channel 2‘s Capture/Compare interrupt enable
Refer to CH0IF description
2
CH1IF
Channel 1‘s Capture/Compare interrupt enable
Refer to CH0IF description
1
CH0IF
Channel 0‘s Capture/Compare interrupt flag
This flag is set by hardware and cleared by software. When channel 0 is in input
mode, this flag is set when a capture event occurs. When channel 0 is in output
mode, this flag is set when a compare event occurs.
0: No Channel 0 interrupt occurred
1: Channel 0 interrupt occurred
0
UPIF
Update interrupt flag
This bit is set by hardware on an update event and cleared by software.
0: No update interrupt occurred
1: Update interrupt occurred
GD32F1x0 User Manual
189
Software event generation register (TIMERx_SWEVG)
Address offset: 0x14
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
BRKG
TRGG
CMTG
CH3G
CH2G
CH1G
CH0G
UPG
w
w
w
w
w
w
w
w
Bits
Fields
Descriptions
15:8
Reserved
Must be kept at reset value.
7
BRKG
Break event generation
This bit is set by software and cleared by hardware automatically. When this bit is
set, the POEN bit is cleared and BRKIF flag is set, related interrupt or DMA transfer
can occur if enabled.
0: No generate a break event
1: Generate a break event
6
TRGG
Trigger event generation
This bit is set by software and cleared by hardware automatically. When this bit is
set, the TRGIF flag in TIMERx_INTF register is set, related interrupt or DMA
transfer can occur if enabled.
0: No generate a trigger event
1: Generate a trigger event
5
CMTG
Channel commutation event generation
This bit is set by software and cleared by hardware automatically. When this bit is
set the channel control registers (CHxEN, CHxNEN and CHxCOMCTL bits) of the
channels having a complementary output are updated.
0: no affect
1: generate channel’s capture/compare control update event
4
CH3G
Channel 3’s capture or compare event generation
Refer to CH0G description
3
CH2G
Channel 2’s capture or compare event generation
Refer to CH0G description
2
CH1G
Channel 1’s capture or compare event generation
Refer to CH0G description
1
CH0G
Channel 0’s capture or compare event generation
This bit is set by software in order to generate a capture or compare event in
channel 0, it is automatically cleared by hardware. When this bit is set, the CH0IF
flag is set, the corresponding interrupt or DMA request is sent if enabled. In
GD32F1x0 User Manual
190
addition, if channel 0 is configured in input mode, the current value of the counter is
captured in TIMER0_CH0CV register, and the CH0OF flag is set if the CH0IF flag
was already high.
0: No generate a channel 0 capture or compare event
1: Generate a channel 0 capture or compare event
0
UPG
This bit can be set by software, and cleared by hardware automatically. When this
bit is set, the counter is cleared if the center-aligned or upcounting mode is
selected, else (downcounting) it takes the auto-reload value. The prescaler counter
is cleared at the same time.
0: No generate an update event
1: Generate an update event
Channel control register 0 (TIMERx_CHCTL0)
Address offset: 0x18
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
CH1COM
CEN
CH1COMCTL[
2:0]
CH1COM
SEN
CH1COM
FEN
CH1MS[1
:0]
CH0COM
CEN
CH0COMCTL[
2:0]
CH0COM
SEN
CH0COM
FEN
CH0MS[1
:0]
CH1CAPFLT[3:0]
CH1CAPPSC[1:0]
CH0CAPFLT[3:0]
CH0CAPPSC[1:0]
rw
rw
rw
rw
rw
rw
Output compare mode:
Bits
Fields
Descriptions
15
CH1COMCEN
Channel 1 output compare clear enable
Refer to CH0COMCEN description
14:12
CH1COMCTL[2:0]
Channel 1 output compare mode
Refer to CH0COMCTL description
11
CH1COMSEN
Channel 1 output compare shadow enable
Refer to CH0COMSEN description
10
CH1COMFEN
Channel 1 output compare fast enable
Refer to CH0COMFEN description
9:8
CH1MS[1:0]
Channel 1 mode selection
This bit-field specifies the direction of the channel and the input signal selection.
This bit-field is writable only when the channel is OFF (CH1EN bit in
TIMER0_CHCTL2 register is reset).
00: channel 1 is configured as output
01: channel 1 is configured as input, IC1 is connected to CI1FE1
10: channel 1 is configured as input, IC1 is connected to CI0FE1
11: channel 1 is configured as input, IC1 is connected to ITS. This mode is
GD32F1x0 User Manual
191
working only if an internal trigger input is selected through TRGS bits in
TIMERx_SMCFG register.
7
CH0COMCEN
Channel 0 output compare clear enable.
When this bit is set, the O0CPRE signal is cleared when High level is detected on
ETIF input.
0: Channel 0 output compare clear disable
1: Channel 0 output compare clear enable
6:4
CH0COMCTL[2:0]
Channel 0 compare output control
This bit-field specifies the behavior of the output reference signal O0CPRE which
drives CH0_O and CH0_ON. O0CPRE is active high, while CH0_O and CH0_ON
active level depends on CH0P and CH0NP bits.
000: Frozen.The O0CPRE signal keeps stable, independent of the comparison
between the register TIMER0_CH0CV and the counter.
001: Set the channel output. O0CPRE signal is forced high when the counter
matches the output compare register TIMERx_CH0CV.
010: Clear the channel output. O0CPRE signal is forced low when the counter
matches the output compare register TIMERx_CH0CV.
011: Toggle on match. O0CPRE toggles when the counter matches the output
compare register TIMERx_CH0CV.
100: Force low. O0CPRE is forced low level.
101: Force high. O0CPRE is forced high level.
110: PWM mode 0. When counting up, O0CPRE is high as long as the counter is
smaller than TIMER0_CH0CV else low. When counting down, O0CPRE is low as
long as the counter is larger than TIMER0_CH0CV else high.
111: PWM mode 1. When counting up, O0CPRE is low as long as the counter is
smaller than TIMER0_CH0CV else high. When counting down, O0CPRE is high as
long as the counter is larger than TIMER0_CH0CV else low.
When configured in PWM mode, the O0CPRE level changes only when the output
compare mode switches from “frozen” mode to “PWM” mode or when the result of
the comparison changes.
This bit cannot be modified when PROT[1:0] bit-filed in TIMERx_CCHP register is
11 and CH0MS bit-filed is 00.
3
CH0COMSEN
Channel 0 output compare shadow enable
When this bit is set, the shadow register of TIMER0_CH0CV register, which updates
at each update event will be enabled.
0: Channel 0 output compare shadow disable
1: Channel 0 output compare shadow enable
The PWM mode can be used without validating the shadow register only in one
pulse mode (SPM bit set in TIMER0_CTL0 register is set).
This bit cannot be modified when PROT[1:0] bit-filed in TIMERx_CCHP register is
11 and CH0MS bit-filed is 00.
2
CH0COMFEN
Channel 0 output compare fast enable
GD32F1x0 User Manual
192
When this bit is set, the effect of an event on the trigger in input on the
capture/compare output will be accelerated if the channel is configured in PWM0 or
PWM1 mode. The output channel will treat an active edge on the trigger input as a
compare match, and CH0_O is set to the compare level independently from the
result of the comparison.
0: Channel 0 output compare fast disable. The minimum delay from an edge on the
trigger input to activate CH0_O output is 5 clock cycles.
1: Channel 0 output compare fast enable. The minimum delay from an edge on the
trigger input to activate CH0_O output is 3 clock cycles.
1:0
CH0MS[1:0]
Channel 0 I/O mode selection
This bit-field specifies the direction of the channel and the input signal selection.
This bit-field is writable only when the channel is OFF (CH0EN bit in
TIMER0_CHCTL2 register is reset).
00: Channel 0 is configured as output
01: Channel 0 is configured as input, IC0 is connected to CI0FE0
10: Channel 0 is configured as input, IC0 is connected to CI1FE0
11: Channel 0 is configured as input, IC0 is connected to ITS. This mode is working
only if an internal trigger input is selected through TRGS bits in TIMERx_SMCFG
register.
Input capture mode:
Bits
Fields
Descriptions
15:12
CH1CAPFLT[3:0]
Channel 1 input capture filter control
Refer to CH0CAPFLT description
11:10
CH1CAPPSC[1:0]
Channel 1 input capture prescaler
Refer to CH0CAPPSC description
9:8
CH1MS[1:0]
Channel 1 mode selection
This bit-field specifies the direction of the channel and the input signal selection.
This bit-field is writable only when the channel is OFF (CH1EN bit in
TIMER0_CHCTL2 register is reset).
00: Channel 1 is configured as output
01: Channel 1 is configured as input, IC1 is connected to CI1FE1
10: Cchannel 1 is configured as input, IC1 is connected to CI0FE1
11: Channel 1 is configured as input, IC1 is connected to ITS. This mode is
working only if an internal trigger input is selected through TRGS bits in
TIMERx_SMCFG register.
7:4
CH0CAPFLT[3:0]
Channel 0 input capture filter control
An event counter is used in the digital filter, in which a transition on the output
occurs after N input events. This bit-field specifies the frequency used to sample
CI0 input signal and the length of the digital filter applied to CI0.
0000: Filter disable, fSAMP=fDTS, N=1
GD32F1x0 User Manual
193
0001: fSAMP= fTIMER_CK, N=2
0010: fSAMP= fTIMER_CK, N=4
0011: fSAMP= fTIMER_CK, N=8
0100: fSAMP=fDTS/2, N=6
0101: fSAMP=fDTS/2, N=8
0110: fSAMP=fDTS/4, N=6
0111: fSAMP=fDTS/4, N=8
1000: fSAMP=fDTS/8, N=6
1001: fSAMP=fDTS/8, N=8
1010: fSAMP=fDTS/16, N=5
1011: fSAMP=fDTS/16, N=6
1100: fSAMP=fDTS/16, N=8
1101: fSAMP=fDTS/32, N=5
1110: fSAMP=fDTS/32, N=6
1111: fSAMP=fDTS/32, N=8
3:2
CH0CAPPSC[1:0]
Channel 0 input capture prescaler
This bit-field specifies the ratio of the prescaler on channel 0 input.The prescaler is
reset when CH0EN bit in TIMER0_CHCTL2 register is reset.
00: Prescaler disable, capture is done on each channel input edge
01: Capture is done every 2 channel input edges
10: Capture is done every 4 channel input edges
11: Capture is done every 8 channel input edges
1:0
CH0MS[1:0]
Channel 0 mode selection
This bit-field specifies the direction of the channel and the input signal selection.
This bit-field is writable only when the channel is OFF (CH0EN bit in
TIMER0_CHCTL2 register is reset).
00: Channel 0 is configured as output
01: Channel 0 is configured as input, IC0 is connected to CI0FE0
10: Channel 0 is configured as input, IC0 is connected to CI1FE0
11: Channel 0 is configured as input, IC0 is connected to ITS. This mode is
working only if an internal trigger input is selected through TRGS bits in
TIMERx_SMCFG register.
Channel control register 1 (TIMERx_CHCTL1)
Address offset: 0x1C
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
CH3COM
CEN
CH3COMCTL[
2:0]
CH3COM
SEN
CH3COM
FEN
CH3MS[1
:0]
CH2COM
CEN
CH2COMCTL[
2:0]
CH2COM
SEN
CH2COM
FEN
CH2MS[1
:0]
CH3CAPFLT[3:0]
CH3CAPPSC[1:0]
CH2CAPFLT[3:0]
CH2CAPPSC[1:0]
rw
rw
rw
rw
rw
rw
GD32F1x0 User Manual
194
Output compare mode
Bits
Fields
Descriptions
15
CH3COMCEN
Channel 3 output compare clear enable
Refer to CH0COMCEN description
14:12
CH3COMCTL[2:0]
Channel 3 compare output control
Refer to CH0COMCTL description
11
CH3COMSEN
Channel 3 output compare shadow enable
Refer to CH0COMSEN description
10
CH3COMFEN
Channel 3 output compare fast enable
Refer to CH0COMFEN description
9:8
CH3MS[1:0]
Channel 3 mode selection
This bit-field specifies the direction of the channel and the input signal selection.
This bit-field is writable only when the channel is OFF (CH3EN bit in
TIMER0_CHCTL2 register is reset).
00: Channel 3 is configured as output
01: Channel 3 is configured as input, IC3 is connected to CI3FE3
10: Channel 3 is configured as input, IC3 is connected to CI2FE3
11: Channel 3 is configured as input, IC3 is connected to ITS. This mode is
working only if an internal trigger input is selected through TRGS bits in
TIMERx_SMCFG register.
7
CH2COMCEN
Channel 2 output compare clear enable
Refer to CH0COMCEN description
6:4
CH2COMCTL[2:0]
Channel 2 compare output control
Refer to CH0COMCTL description
3
CH2COMSEN
Channel 2 output compare shadow enable
Refer to CH0COMSEN description
2
CH2COMFEN
Channel 2 output compare fast enable
Refer to CH0COMFEN description
1:0
CH2MS[1:0]
Channel 2 mode selection
This bit-field specifies the direction of the channel and the input signal selection.
This bit-field is writable only when the channel is OFF (CH2EN bit in
TIMER0_CHCTL2 register is reset).
00: Channel 2 is configured as output
01: Channel 2 is configured as input, IC2 is connected to CI2FE2
10: Channel 2 is configured as input, IC2 is connected to CI3FE2
11: Channel 2 is configured as input, IC2 is connected to ITS. This mode is
working only if an internal trigger input is selected through TRGS bits in
TIMERx_SMCFG register.
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Input capture mode:
Bits
Fields
Descriptions
15:12
CH3CAPFLT[3:0]
Channel 3 input capture filter control
Refer to CH0CAPFLT description
11:10
CH3CAPPSC[1:0]
Channel 3 input capture prescaler
Refer to CH0CAPPSC description
9:8
CH3MS[1:0]
Channel 3 mode selection
This bit-field specifies the direction of the channel and the input signal selection.
This bit-field is writable only when the channel is OFF (CH3EN bit in
TIMER0_CHCTL2 register is reset).
00: channel 3 is configured as output
01: channel 3 is configured as input, IC3 is connected to CI3FE3
10: channel 3 is configured as input, IC3 is connected to CI2FE3
11: channel 3 is configured as input, IC3 is connected to ITS. This mode is
working only if an internal trigger input is selected through TRGS bits in
TIMERx_SMCFG register.
7:4
CH2CAPFLT[3:0]
Channel 2 input capture filter control
Refer to CH0CAPFLT description
3:2
CH2CAPPSC[1:0]
Channel 2 input capture prescaler
Refer to CH0CAPPSC description
1:0
CH2MS[1:0]
Channel 2 mode selection
This bit-field specifies the direction of the channel and the input signal selection.
This bit-field is writable only when the channel is OFF (CH2EN bit in
TIMER0_CHCTL2 register is reset).
00: channel 2 is configured as output
01: channel 2 is configured as input, IC2 is connected to CI2FE2
10: channel 2 is configured as input, IC2 is connected to CI3FE2
11: channel 2 is configured as input, IC2 is connected to ITS. This mode is
working only if an internal trigger input is selected through TRGS bits in
TIMERx_SMCFG register.
Channel control register 2 (TIMERx_CHCTL2)
Address offset: 0x20
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
CH3P
CH3EN
CH2NP
CH2NEN
CH2P
CH2EN
CH1NP
CH1NEN
CH1P
CH1EN
CH0NP
CH0NEN
CH0P
CHt0EN
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
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Bits
Fields
Descriptions
15:14
Reserved
Must be kept at reset value
13
CH3P
Channel 3 polarity
Refer to CH0P description
12
CH3EN
Channel 3 enable
Refer to CH0EN description
11
CH2NP
Channel 2 complementary output polarity
Refer to CH0NP description
10
CH2NEN
Channel 2 complementary output enable
Refer to CH0NEN description
9
CH2P
Channel 2 polarity
Refer to CH0P description
8
CH2EN
Channel 2 enable
Refer to CH0EN description
7
CH1NP
Channel 1 complementary output polarity
Refer to CH0NP description
6
CH1NEN
Channel 1 complementary output enable
Refer to CH0NEN description
5
CH1P
Channel 1 polarity
Refer to CH0P description
4
CH1EN
Channel 1 enable
Refer to CH0EN description
3
CH0NP
Channel 0 complementary output polarity
When channel 0 is configured in output mode, this bit specifies the complementary
output signal polarity.
0: Channel 0 active high
1: Channel 0 active low
When channel 0 is configured in input mode, In conjunction with CH0P, this bit is
used to define the polarity of CI0.
This bit cannot be modified when PROT[1:0] bit-filed in TIMERx_CCHP register is
11 or 10.
2
CH0NEN
Channel 0 complementary output enable
When channel 0 is configured in output mode, setting this bit enables the
complementary output in channel 0.
0: Channel 0 complementary output disabled
1: Channel 0 complementary output enabled
1
CH0P
Channel 0 polarity
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When channel 0 is configured in output mode, this bit specifies the output signal
polarity.
0: Channel 0 active high
1: Channel 0 active low
When channel 0 is configured in input mode, this bit specifies the CI0 signal
polarity.
[CH0NP, CH0P] will selete the active trigger or capture polarity for CI0FE0 or
CI1FE0.
[CH0NP==0, CH0P==0]: CIxFE0’s rising edge is the active signal for capture or
trigger operation in slave mode. And CIxFE0 will not be inverted.
[CH0NP==0, CH0P==1]: CIxFE0’s falling edge is the active signal for capture or
trigger operation in slave mode. And CIxFE0 will be inverted.
[CH0NP==1, CH0P==0]: Reserved.
[CH0NP==1, CH0P==1]: CIxFE0’s falling and rising edge are both the active signal
for capture or trigger operation in slave mode. And CIxFE0 will be not inverted.
This bit cannot be modified when PROT [1:0] bit-filed in TIMERx_CCHP register is
11 or 10.
0
CH0EN
Channel 0 enable
When channel 0 is configured in input mode, setting this bit enables CH0_O signal
in active state. When channel 0 is configured in output mode, setting this bit enables
the capture event in channel 0.
0: Channel 0 disabled
1: Channel 0 enabled
Counter register (TIMERx_CNT)
Address offset: 0x24
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
CNT[15:0]
rw
Bits
Fields
Descriptions
15:0
CNT[15:0]
This bit-filed indicates the current counter value. Writing to this bit-filed can change
the value of the counter.
Prescaler register (TIMERx_PSC)
Address offset: 0x28
Reset value: 0x0000
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This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
PSC[15:0]
rw
Bits
Fields
Descriptions
15:0
PSC[15:0]
Prescaler value of the counter clock
The PSC clock is divided by (PSC+1) to generate the counter clock. The value of
this bit-filed will be loaded to the corresponding shadow register at every update
event.
Counter auto reload register (TIMERx_CAR)
Address offset: 0x2C
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
CAR[15:0]
rw
Bits
Fields
Descriptions
15:0
CAR[15:0]
Counter auto reload value
This bit-filed specifies the auto reload value of the counter.
Counter repetition register (TIMERx_CREP)
Address offset: 0x30
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
CREP[7:0]
rw
Bits
Fields
Descriptions
15:8
Reserved
Must be kept at reset value.
7:0
CREP[7:0]
Counter repetition value
This bit-filed specifies the update event generation rate. Each time the repetition
counter counting down to zero, an update event is generated. The update rate of
the shadow registers is also affected by this bit-filed when these shadow registers
are enabled.
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Channel 0 capture/compare value register (TIMERx_CH0CV)
Address offset: 0x34
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
CH0VAL[15:0]
rw
Bits
Fields
Descriptions
15:0
CH0VAL[15:0]
Capture or compare value of channel 0
When channel 0 is configured in input mode, this bit-filed indicates the counter
value corresponding to the last capture event. And this bit-filed is read-only.
When channel 0 is configured in output mode, this bit-filed contains value to be
compared to the counter. When the corresponding shadow register is enabled, the
shadow register updates every update event.
Channel 1 capture/compare value register (TIMERx_CH1CV)
Address offset: 0x38
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
CH1VAL[15:0]
rw
Bits
Fields
Descriptions
15:0
CH1VAL[15:0]
Capture or compare value of channel 1
When channel 1 is configured in input mode, this bit-filed indicates the counter
value corresponding to the last capture event. And this bit-filed is read-only.
When channel 1 is configured in output mode, this bit-filed contains value to be
compared to the counter. When the corresponding shadow register is enabled, the
shadow register updates every update event.
Channel 2 capture/compare value register (TIMERx_CH2CV)
Address offset: 0x3C
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
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CH2VAL[15:0]
rw
Bits
Fields
Descriptions
15:0
CH2VAL[15:0]
Capture or compare value of channel 2
When channel 2 is configured in input mode, this bit-filed indicates the counter
value corresponding to the last capture event. And this bit-filed is read-only.
When channel 2 is configured in output mode, this bit-filed contains value to be
compared to the counter. When the corresponding shadow register is enabled, the
shadow register updates every update event.
Channel 3 capture/compare value register (TIMERx_CH3CV)
Address offset: 0x40
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
CH3VAL[15:0]
rw
Bits
Fields
Descriptions
15:0
CH3VAL[15:0]
Capture or compare value of channel 3
When channel 3 is configured in input mode, this bit-filed indicates the counter
value corresponding to the last capture event. And this bit-filed is read-only.
When channel 3 is configured in output mode, this bit-filed contains value to be
compared to the counter. When the corresponding shadow register is enabled, the
shadow register updates every update event.
Channel Complementary Protection register (TIMERx_CCHP)
Address offset: 0x44
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
POEN
OAEN
BRKP
BRKEN
ROS
IOS
PROT[1:0]
DTCFG[7:0]
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
15
POEN
Primary output enable
This bit s set by software or automatically by hardware depending on the OAEN bit.
It is cleared asynchronously by hardware assoon as the break input is active. When
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a channel is configured in output mode, setting this bit enables the channel outputs
(CHx_O and CHx_ON) if the corresponding enable bits (CHxEN, CHxNEN in
TIMERx_CHCTL2 register) have been set.
0: Channel outputs are disabled or forced to idle state.
1: Channel outputs are enabled.
14
OAEN
Output automatic enable
This bit specifies whether the POEN bit can be set automatically by hardware.
0: POEN can be not set by hardware.
1: POEN can be set by hardware automatically at the next update event,if the break
input is notactive.
This bit can be modified only when PROT[1:0] bit-filed in TIMERx_CCHP register is
00.
13
BRKP
Break polarity
This bit specifies the polarity of the BRK input signal.
0: BRK input active low
1; BRK input active high
12
BRKEN
Break enable
This bit can be set to enable the BRK and CCS clock failure event inputs.
0: Break inputs disabled
1; Break inputs enabled
This bit can be modified onlywhen PROT[1:0] bit-filed in TIMERx_CCHP register is
00.
11
ROS
Run mode off-state configure
When POEN bit is set, this bit specifies the output state for the channels which has
a complementary output and has been configured in output mode.
0: When POEN bit is set, the channel output signals (CHx_O/CHx_ON) are
disabled.
1: When POEN bit is set, the channel output signals (CHx_O/CHx_ON) are
enabled, with relationship to CHxEN/CHxNEN bits in TIMER0_CHCTL2 register.
This bit cannot be modified when PROT[1:0] bit-filed in TIMERx_CCHP register is
10 or 11.
10
IOS
Idle mode off-state configure
When POEN bit is reset, this bit specifies the output state for the channels which
has been configured in output mode.
0: When POEN bit is reset, the channel output signals (CHx_O/CHx_ON) are
disabled.
1: When POEN bit is reset, he channel output signals (CHx_O/CHx_ON) are
enabled, with relationship to CHxEN/CHxNEN bits in TIMER0_CHCTL2 register.
This bit cannot be modified when PROT [1:0] bit-filed in TIMERx_CCHP register is
10 or 11.
9:8
PROT[1:0]
Complementary register protect control
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This bit-filed specifies the write protection property of registers.
00: protect disable. No write protection.
01: PROT mode 0.The ISOx/ISOxN bits in TIMER0_CTL1 register and the
BRKEN/BRKP/OAEN/DTCFG bits in TIMER0_CCHP register are writing protected.
10: PROT mode 1. In addition of the registers in PROT mode 0, the CHxP/CHxNP
bits in TIMERx_CHCTL2 register (if related channel is configured in output mode)
and the ROS/IOS bits in TIMER0_CCHP register are writing protected.
11: PROT mode 2. In addition of the registers in PROT mode 1, the
CHxCOMCTL/CHxCOMSEN bits in TIMER0_CHCTLx registers (if the related
channel is configured in output) are writing protected.
This bit-field can be written only once after the reset. Once the TIMERx_CCHP
register has been written, this bit-field will be writing protected.
7:0
DTCFG[7:0]
Dead time configure
This bit-field specifies the duration of the dead-time, which is inserted before the
output transitions. The relationship between DTCFG value and the duration of dead-
time is as follow:
DTCFG[7:5]=0xx: duration =DTCFG[7:0]x tDT, tDT=tDTS.
DTCFG[7:5]=10x:duration =(64+DTCFG[5:0])xtDT,tDT=tDTS*2.
DTCFG[7:5]=110: duration =(32+DTCFG[4:0])xtDT, tDT=tDTS*8.
DTCFG[7:5]=111:duration =(32+DTCFG[4:0])xtDT,tDT=tDTS*16.
This bit can be modified only when PROT[1:0] bit-filed in TIMERx_CCHP register is
00.
DMA configuration register (TIMERx_DMACFG)
Address offset: 0x48
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
DMATC[4:0]
Reserved
DMATA[4:0]
rw
rw
Bits
Fields
Descriptions
15:14
Reserved
Must be kept at reset value.
12:8
DMATC[4:0]
DMA transfer count
When register access are done through the TIMERx_DMATB address, this 5-bit bit-
field specifies the number of transfers.
7:5
Reserved
Must be kept at reset value.
4:0
DMATA[4:0]
DMA transfer access start address
When register access are done through the TIMERx_DMATB address, this bit-field
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specifies the offset of the starting address from the TIMER0_CTL0 register.
DMA Transfer buffer register (TIMERx_DMATB)
Address offset: 0x4C
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
DMATB[15:0]
rw
Bits
Fields
Descriptions
15:0
DMATB[15:0]
DMA transfer
When a read or write operation is assigned to this register, the register located at
the address range (DMATA + burst counter) x 4 from TIMERx_CTL0 will be
accessed.
The burst counter is calculated by hardware, and ranges from 0 to DMATC.
Configuration register (TIMERx_CFG) of GD32F170xx and GD32F190xx
devices
Address offset: 0xFC
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
CCSEL
OUTSEL
rw
rw
Bits
Fields
Descriptions
15:2
Reserved
Must be kept at reset value
1
CCSEL
Write Capture/Compare register selection
This bit-field set and reset by software.
1: If write the Capture/Compare register, the write value is same as the
Capture/Compare value, the write access ignored
0: No effect
0
OUTSEL
The output value selection
This bit-field set and reset by software
1: If POEN and IOS is 0, the output disabled
0: No effect
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9.2. General timers (TIMER1/TIMER2)
9.2.1. Introduction
The general timers (TIMER1 and TIMER2) consist of one 16-bit or 32-bit up/down-counter;
four capture/compare registers (TIMERx_CHxCV), one counter auto reload register
(TIMERx_CAR) and several control registers. They can be used for a variety of purposes
including general timer, input signal pulse width measurement or output waveform generation
such as single pulse generation or PWM output. The TIMERx supports an Encoder Interface
using a decoder with two inputs.
9.2.2. Main features
16-bit (TIMER2) or 32-bit (TIMER1) down, up, down/up auto-reload counter.
16-bit programmable prescaler that allows division of the counter clock frequency by any
factor between 1 and 65536.
Up to 4 independent channels support functions including input capture, compare match
output, generation of PWM waveform (edge and center-aligned Mode), and single pulse
mode output.
Interrupt/DMA generation by update, trigger event, input capture event, output compare
match event
Synchronization circuit to control TIMERx with external signals or to interconnect several
timers together.
Encoder interface controller with two inputs using quadrature decoder
TIMERx Master/Slave mode controller
9.2.3. Function description
Figure below provides details on the internal configuration of the general timer.
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205
Figure 9-46. General timer block diagram (TIMER1 and TIMER2)
Trigger
Controller
Mode Slave
Controller
Encoder
Interface
ITI0
ITI1
ITI2
ITI3
ETI Edge Detector
Polarity Selection
Prescaler
Input Filter
CI0FE0
CI1FE0
CI0F_ED
TIMERx_TRGO
CH0
CH1
CH2
CH3
XOR
Input Filter Edge Detector Prescaler
Capture Register
Compare Register
Prescaler
Counter
AutoReload
Register
Output
Control
CH0
CH1
CH2
CH3
Reset, Enable, Up/Down, Count
Prescaler counter
The prescaler can divide the timer clock (TIMER_CK) to the counter clock (CNT_CLK) by any
factor between 1 and 65536. It is controlled through prescaler register (TIMERx_PSC) which
can be changed on the fly but be taken into account at the next update event.
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206
Figure 9-47. Counter timing diagram with prescaler division change from 1 to 2
TIMER_CK
CEN
CNT_CLK
CNT_REG
Reload Pulse
Prescaler CNT
Prescaler BUF
Prescaler CR
F7 F8 F9 FA FB FC 01 02 03 04
01
0 1
0 0 1 0 1 0 1 0 1
modify scaler Vaule
Figure 9-48. Counter timing diagram with prescaler division change from 1 to 4
TIMER_CK
CEN
CNT_CLK
CNT_REG
Reload Pulse
Prescaler CNT
Prescaler BUF
Prescaler CR
F7 F8 F9 FA FB FC 00 01
03
0 3
0 0 1 2 3 0 1 2 3
modify PSC Vaule
Upcounting mode
In this mode the counter counts continuously from 0 to the counter-reload value, which is
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207
defined in the TIMERx_CAR register, in a count-up direction. Once the counter reaches the
counter reload value, the counter restarts to count once again from 0. The update event is
generated at each counter overflow.The counting direction bit DIR in the TIMERx_CTL0
register should be set to 0 for the upcounting mode.
When the update event is set by the UPG bit in the TIMERx_SWEVG register, the counter
value will be initialized to 0 and generates an update event.
If set the UPDIS bit in TIMERx_CTL0 register, the update event is disabled.
When an update event occurs, all the registers (autoreload register, prescaler register) are
updated.
The following figures show some examples of the counter behavior for different clock
frequencies when TIMERx_CAR=0x63.
Figure 9-49. Counter timing diagram, internal clock divided by 1
PCLK
EN
CNT_CLK
CNT_REG
overflow
5E 5F 60 61 62 63 00 01 02 03 04 05 06 07
Update event (UPE)
Update interrupt flag (UPIF)
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Figure 9-50. Counter timing diagram, internal clock divided by 2
PCLK
EN
CNT_CLK
CNT_REG
overflow
61
Update event (UPE)
Update interrupt flag (UPIF)
62 63 00 01 02 03 04
Figure 9-51. Counter timing diagram, internal clock divided by 4
PCLK
EN
CNT_CLK
CNT_REG
overflow
62
Update event (UPE)
Update interrupt flag (UPIF)
63 00 01
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Figure 9-52. Counter timing diagram, internal clock divided by N
TIMER_CK
CNT_CLK
CNT_REG
overflow
31
Update event (UPE)
Update interrupt flag (UPIF)
32 00
Figure 9-53. Counter timing diagram, update event when ARSE=0
TIMER_CK
CEN
CNT_CLK
CNT_REG
overflow
5E 5F 60 61 62 63 00 01 02 03 04 05 06 07
Update event (UPE)
Update interrupt flag (UPIF)
Auto-reload register 65 63
modify CAR Vaule
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Figure 9-54. Counter timing diagram, update event when ARSE=1
TIMER_CK
CEN
CNT_CLK
CNT_REG
overflow
60 61 62 63 64 65 00 01 02 03 04 05 06 07
Update event (UPE)
Update interrupt flag (UPIF)
Auto-reload register 65 63
modify CAR Vaule
Auto-reload shadow register 65 63
Downcounting mode
In this mode the counter counts continuously from the counter reload value, which is defined
in the TIMERx_CAR register, to 0 in a count-down direction. Once the counter reaches 0, the
counter restarts to count once again from the counter-reload value. If the repetition counter is
set, the update event generated after the number of underflow. Else the update event is
generated at each counter underflow. The counting direction bit DIR in the TIMERx_CTL0
register should be set to 1 for the down counting mode.
When the update event is set by the UPG bit in the TIMERx_SWEVG register, the counter
value will be initialized to the counter-reload value and generates an update event.
If set the UPDIS bit in TIMERx_CTL0 register, the update event is disabled.
When an update event occurs, all the registers (repeat counter, reload register, prescaler
register) are updated.
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Figure 9-55. Counter timing diagram, internal clock divided by 1
PCLK
EN
CNT_CLK
CNT_REG
overflow
05 04 03 02 01 00 63 62 61 60 5F 5E 5D 5C
Update event (UPE)
Update interrupt flag (UPIF)
Figure 9-56. Counter timing diagram, internal clock divided by 2
TIMER_CK
CEN
CNT_CLK
CNT_REG
overflow
002
Update event (UPE)
Update interrupt flag (UPIF)
001 000 063 062 061 060 05F
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Figure 9-57. Counter timing diagram, internal clock divided by 4
TIMER_CK
CEN
CNT_CLK
CNT_REG
overflow
001
Update event (UPE)
Update interrupt flag (UPIF)
000 063 062
Figure 9-58. Counter timing diagram, internal clock divided by N
TIMER_CK
CNT_CLK
CNT_REG
overflow
030
Update event (UPE)
Update interrupt flag (UPIF)
02F063
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213
Figure 9-59. Counter timing diagram, update event when counter is not used
TIMER_CK
CEN
CNT_CLK
CNT_REG
overflow
05 04 03 02 01 00 63 62 61 60 5F 5E 5D 5C
Update event (UPE)
Update interrupt flag (UPIF)
Auto-reload register 65 63
modify CAR Vaule
Center-aligned counting mode
In the center-aligned counting mode, the counter counts up from 0 to the counter-reload value
and then counts down to 0 alternatively. The Timer module generates an overflow event when
the counter counts to the counter-reload value subtract 1 in the up-counting mode and
generates an underflow event when the counter counts to 1 in the down-counting mode. The
counting direction bit DIR in the TIMERx_CTL0 register is read-only and indicates the
counting direction when in the center-aligned mode. The counting direction is updated by
hardware automatically.
Setting the UPG bit in the TIMERx_SWEVG register will initialize the counter value to 0
irrespective of whether the counter is counting up or down in the center-align counting mode
and generates an update event.
The UPIF bit in the TIMER0_INTF register can be set to 1 when an underflow event at count-
down (CAM in TIMERx_CTL0 is “01”), an overflow event at count-up (CAM in TIMERx_CTL0
is “10”) or both of them occur (CAM in TIMERx_CTL0 is “11”).
If set the UPDIS bit in the TIMERx_CTL0 register, the update event is disabled.
When an update event occurs, all the registers (autoreload register, prescaler register) are
updated.
The following figures show some examples of the counter behavior for different clock
frequencies when TIMERx_CAR=0x5.
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Figure 9-60. Counter timing diagram, internal clock divided by 1, TIMERx_CAR = 0x5
TIMER_CK
CEN
CNT_CLK
CNT_REG
overflow
04 03 02 01 00 01 02 03 04 05 04 03 02 01
Update event (UPE)
Update interrupt flag (UPIF)
underflow
Figure 9-61. Counter timing diagram, internal clock divided by 2
TIMER_CK
CEN
CNT_CLK
CNT_REG
underflow
003
Update event (UPE)
Update interrupt flag (UPIF)
002 001 000 001 002 003 004
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Figure 9-62. Counter timing diagram, internal clock divided by 4, TIMERx_CAR=0x63
TIMER_CK
CEN
CNT_CLK
CNT_REG
overflow
061
Update event (UPE)
Update interrupt flag (UPIF)
062 063 062
Figure 9-63. Counter timing diagram, internal clock divided by N
TIMER_CK
CNT_CLK
CNT_REG
underflow
030
Update event (UPE)
Update interrupt flag (UPIF)
02F 001 000
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Figure 9-64. Counter timing diagram, update event with ARSE=1(counter underflow)
TIMER_CK
CEN
CNT_CLK
CNT_REG
overflow
06 05 04 03 02 01 00 01 02 03 04 05 06 07
Update event (UPE)
Update interrupt flag (UPIF)
Auto-reload register 65 63
modify CAR Vaule
Auto-reload shadow register 65 63
Figure 9-65. Counter timing diagram, Update event with ARSE=1 (counter overflow)
TIMER_CK
CEN
CNT_CLK
CNT_REG
overflow
7A 7B 7C 7D 7E 7F 63 62 61 60 5F 5E 5D 5C
Update event (UPE)
Update interrupt flag (UPIF)
Auto-reload register 80 63
modify CAR Vaule
Auto-reload shadow register 65 63
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Clock selection
The following describes the Timer Module clock controller which determines the clock source
of the internal prescaler counter.
Internal timer clock TIMER_CK
The default internal clock source is the APB2 clock CK_APB2 used to drive the counter
prescaler when the slave mode is disabled. If the slave mode controller is enabled by setting
SMC field in the TIMERx_SMCFG register to an available value including 0x1, 0x2, 0x3 and
0x7, the prescaler is clocked by other clock sources selected by the TRGS field in the
TIMERx_SMCFG register and described as follows. When the slave mode selection bits SMC
are set to 0x4 , 0x5 or 0x6, the internal clock TIMER_CK is the counter prescaler driving clock
source.
Figure 9-66. Control circuit in normal mode, internal clock divided by 1
TIMER_CK
CEN
CNT_CLK
CNT_REG
Reload Pulse
17 18 19 20 21 22
UPG
23 00 01 02 03 04 05 06
Quadrature decoder
To select Quadrature Decoder mode the SMC field should be set to 0x1, 0x2 or 0x3 in the
TIMERx_SMCFG register. The Quadrature Decoder function uses two input states of the
TIMERx_CH0 and TIMERx_CH1 pins to generate the clock pulse to drive the counter
prescaler. The counting direction bit DIR is modified by hardware automatically at each
transition on the input source signal. The input source signal can be derived from the
TIMERx_CH0 pin only, the TIMERx_CH1 pin only or both TIMERx_CH0 and TIMERx_CH1
pins.
Internal trigger inputs (ITI)
The counter prescaler can count during each rising or falling edge of the ITI signal. This mode
can be selected by setting the SMC field to 0x6 in the TIMERx_SMCFG Rregister; here the
counter will act as an event counter. The input event, known as ITI here, can be selected by
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setting the TRGS field. When the ITI signal is selected as the clock source, the internal edge
detection circuitry will generate a clock pulse during each ITI signal rising or falling edge to
drive the counter prescaler.
Channel input pin (CI)
The counter prescaler can be driven to count during each rising or falling edge on the external
pin TIMERx_CIx. This mode can be selected by setting SMC field to 0x7 and the TRGS field
to 0x4, 0x5 or 0x6. Note that the CIx is derived from the TIMERx_CHx sampled by a digital
filter.
External trigger input (ETIF)
The counter prescaler can be driven to count during each rising or falling edge on the external
pin TIMERx_ETI. This mode can be selected by setting the SMC1 bit in the TIMERx_SMCFG
register to 1. The other way to select the ETIF signal as the clock source is to set the SMC
field to 0x6 and the TRGS field to 0x7 respectively. Note that the ETIF signal is derived from
the TIMERx_ETI pin sampled by a digital filter. When the clock source is selected to come
from the ETIF signal, the Trigger Controller including the edge detection circuitry will generate
a clock pulse during each ETIF signal rising edge to clock the counter prescaler.
Capture/compare channels
The TIMER1/2 has four independent channels which can be used as capture inputs or
compare match outputs. Each channel is built around a channel capture/compare value
register including an input stage, channel controller and an output stage.
Input capture stage
The input stage consists of a digital filter, a channel polarity selection, edge detection and a
channel prescaler. The channel 0 input signal (CI0) can be chosen to come from the
TIMERx_CH0 signal or the Excusive-OR function of the TIMERx_CH0, TIMERx_CH1 and
TIMERx_CH2 signals. The channel input signal (CIx) is sampled by a digital filter to generate
a filtered input signal CIxF. Then the channel polarity and the edge detection block can
generate a CIxFEx signal for the input capture function. The effective input event number can
be set by the channel input prescaler (CHxCAPPSC).
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Figure 9-67. Capture/compare channel (example: channel 0 input stage)
filter
downcounter
CI0
CH0CAPFLT
[3:0]
CHCTL0
fDTS
Edge Detector CI0F_Falling
CI0F_Rising 0
1
CH0P/
CH0NP
CHCTL2
01
CH0MS[ 1:0 ]
CHCTL0
10
11
CI0FE0
CI1FE0
ITS
divider
/1, /2, /4, /8
CH0CAPPS
C[1:0]
CHCTL0
CH0EN
CHCTL2
IC0
Channel controller
The GPTM has four independent channels which can be used as capture inputs or compare
match outputs.
When used in the input capture mode, the counter value is captured into the TIMERx_CHxCV
shadow register first and then transferred into the TIMERx_CHxCV preload register when the
capture event occurs.
When used in the compare match output mode, the contents of the TIMERx_CHxCV preload
register is copied into the associated shadow register; the counter value is then compared
with the register value.
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Figure 9-68. Capture/compare channel 0 main circuit
APB BUS
MCU-peripheral interface
Capture/compare preload register
Capture/compare shadow
register
Counter
CH0VAL
CH0MS[0]
CH0MS[1]
CH0CAPPSC
CH0EN
CH0G
TIMER_SWEVG
CH0VAL
CH0MS[0]
CH0MS[1]
CH0COMSEN
UPE
CNT>CH0VAL
CNT=CH0VAL
Output stage
The TIMERx has four channels for compare match, single pulse or PWM output function.
Figure 9-69. Output stage of capture/compare channel (channel 0)
Output mode controller
CNT>CH0VAL
CNT=CH0VAL
CH0COMCTL[
2:0]
CHCTL0
ETI
0
1
CH0P
CHCTL2
Output enable
circuit
CHx_O
CHxEN
CHCTL2
CH0COMC
EN
Input capture mode
When the channel is used as a capture input, the counter value is captured into the Channel
Capture/Compare Register (TIMERx_CHxCV) when an effective input signal transition occurs.
Once the capture event occurs, the CHxIF flag in the TIMERx_INTF register is set. If the
CHxIF bit is already set, i.e., the flag has not yet been cleared by software, and another
capture event on this channel occurs, the corresponding channel Over-Capture flag, named
CHxOF, will be set.Once the capture event occurs, a DMA request is generated depending
on the CHxDEN bit and an interrupt is generated depending on the CHxIE bit. The fllowing
step maybe used to implement input capture mode:
Select input signal by set CHxMS bits in the channel control register (TIMERx_CHCTLx).
Add input filter to input signal by set CHxCAPFLT bitst in the the channel control register
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(TIMERx_CHCTLx).
Select input capture edge (rising or falling) by set CHxP/CHxNP bit in the channel control
register 2 (TIMERx_CHCTL2).
If input signal need prescaler, set CHxCAPPSC bits in the the channel control register
(TIMERx_CHCTLx).
If need interrupt, set CHxIE bit in DMA and interrupt enable register
(TIMERx_DMAINTEN) to 1.
If need DMA request, set CHxDEN bit in DMA and interrupt enable register
(TIMERx_DMAINTEN) to 1.
Enable the channel by set CHxEN bit in the channel control register 2 (TIMERx_CHCTL2)
to 1.
After configure this registers, the input capture event on this channel may occurs at the
corresponding edge. And the counter value is captured into the Channel Capture/Compare
Register (TIMERx_CHxCV). An interrupt generated if CHxIE bit set. A DMA request
generated if CHxDEN set.
The input capture mode can be also used for pulse width measurement from signals on the
TIMERx_CHx pins (CIx). For example, PWM signal connect to CI0 input. Select channel 0
capture signal to CI0 by setting CH0MS to 01 in the channel control register
(TIMERx_CHCTL0) and set capture on rising edge. Select channel 1 capture signal to CI0 by
setting CH1MS to 10 in the channel control register (TIMERx_CHCTL0) and set capture on
falling edge. The counter set to restart mode and restart on channel 0 rising edge. Then the
TIMERx_CH0CV can measure the PWM period and the TIMERx_CH1CV can measure the
PWM duty.
Output compare mode/PWM mode
When the channel is used as a output mode by setting the CHxMS in the the channel control
register (TIMERx_CHCTLx) to 00, the channel outputs waveform according to the
CHxCOMCTL bits in the the the channel control register (TIMERx_CHCTLx), and the
comparision between the counter and TIMERx_CHxCV registers. When the comparision
equals, the CHxIF flag in the Interrupt flag registers (TIMERx_INTF) set to 1. A DMA request
is generated depending on the CHxDEN bit and an interrupt is generated depending on the
CHxIE bit.
In output mode, the channel can outputs active level by set the CHxCOMCTL to 101, and
outputs inactive level by set the CHxCOMCTL bits to 100.
In ouput mode, the channel output set to active level when the comparision between the
counter and TIMERx_CHxCV registers match, by set the CHxCOMCTL to 001. The channel
output set to inactive level when the comparision between the counter and TIMERx_CHxCV
registers match, by set the CHxCOMCTL to 010.
In output compare toggle mode (by set the CHxCOMCTL to 011), the channel output toggles
when the comparision between the counter and TIMERx_CHxCV registers match.
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Figure 9-70. Output compare toggle mode, toggle on CH0_O
CNT_REG
O0CPRE=CH0_O
003A0039
CH0VAL
003B B200 B201
003A B201
Match detected on CH0VAL
Interrupt generated if enabled
Write B201h in the CH0VAL
register
In the output PWM mode (by setting the CHxCOMCTL bits to 110 (PWM mode 0) or to 111
(PWM mode 1)), the channel can outputs PWM waveform according to the TIMERx_CAR
registers and TIMERx_CHxCV registers.
Figure 9-71. Output compare PWM mode 0 on CH0_O, upcounting mode
CNT_REG
O0CPRE=CH0_O
003A0039
CH0VAL
003B 100 0
003A
Match detected on CH0VAL
Interrupt generated if enabled
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Figure 9-72. Output compare PWM mode 0 on CH0_O, center-aligned counting mode
CNT_REG
O0CPRE=CH0_O
003A0039
CH0VAL
003B 0100 00FF
003A
Match detected on CH0VAL
Interrupt generated if enabled
00FE 003B 003A 0039
Single pulse mode
Once the timer is set to operate in the single pulse mode, it is not necessary to set the timer
enable bit CEN in the TIMERx_CTL0 register to 1 to enable the counter. The trigger to
generate a pulse can be sourced from the trigger signals edge or by setting the CEN bit to 1
using software. Setting the CEN bit to 1 or a trigger from the trigger signals edge can generate
a pulse and then keep the CEN bit at a high state until the update event occurs or the CEN
bit is written to 0 by software. If the CEN bit is cleared to 0 using software, the counter will be
stopped and its value held. If the CEN bit is automatically cleared to 0 by a hardware update
event, the counter will be reinitialized.
In the Single Pulse mode, the trigger active edge which sets the CEN bit to 1 will enable the
counter. However, there exist several clock delays to perform the comparison result between
the counter value and the TIMERx_CHxCV value. In order to reduce the delay to a minimum
value, the user can set the CHxOFE bit in each TIMERx_CHCTL0 register. After a trigger
rising edge occurs in the single pulse mode, the OxCPRE signal will immediately be forced
to the state which the OxCPRE signal will change to, as the compare match event occurs
without taking the comparison result into account. The CHxOFE bit is available only when the
output channel is configured to operate in the PWM0 or PWM1 output mode and the trigger
source is derived from the trigger signal.
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Figure 9-73. Single pulse mode
O0CPRE
CH0_O
CI1
CH0VAL
CARL
T
TIMER_CNT
Channel output reference signal
When the TIMERx is used in the compare match output mode, the OxCPRE signal (Channel
x Output Reference signal) is defined by setting the CHxCOMCTL bits. The OxCPRE signal
has several types of output function. These include, keeping the original level by setting the
CHxCOMCTL field to 0x00, set to 1 by setting the CHxCOMCTL field to 0x01, set to 0 by
setting the CHxCOMCTL field to 0x02 or signal toggle by setting the CHxCOMCTL field to
0x03 when the counter value matches the content of the TIMERx_CHxCV register.
The PWM mode 0 and PWM mode 1 outputs are also another kind of OxCPRE output which
is setup by setting the CHxCOMCTL field to 0x06/0x07. In these modes, the OxCPRE signal
level is changed according to the counting direction and the relationship between the counter
value and the TIMERx_CHxCV content. With regard to a more detailed description refer to
the relative bit definition.
Another special function of the OxCPRE signal is a forced output which can be achieved by
setting the CHxCOMCTL field to 0x04/0x05. Here the output can be forced to an
inactive/active level irrespective of the comparison condition between the counter and the
TIMERx_CHxCV values.
The OxCPRE signal can be forced to 0 when the ETIF signal is derived from the external
TIMERx_ETI pin and when it is set to a high level by setting the CHxCOMCEN bit to 1 in the
TIMERx_CHCTL0 register. The OxCPRE signal will not return to its active level until the next
update event occurs.
Quadrature decoder
The Quadrature Decoder function uses two quadrature inputs CI0 and CI1 derived from the
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TIMERx_CH0 and TIMERx_CH1 pins respectively to interact to generate the counter value.
The DIR bit is modified by hardware automatically during each input source transition. The
input source can be either CI0 only, CI1 only or both CI0 and CI1, the selection made by
setting the SMC field to 0x01, 0x02 or 0x03. The mechanism for changing the counter
direction is shown in the following table. The Quadrature decoder can be regarded as an
external clock with a directional selection. This means that the counter counts continuously
in the interval between 0 and the counter-reload value. Therefore, users must configure the
TIMERx_CAR register before the counter starts to count.
Table 9-2. Counting direction versus encoder signals
Counting
mode
Level
CI0FE0
CI1FE1
Rising
Falling
Rising
Falling
CI0 only
counting
CI1FE=High
Down
Up
-
-
CI1FE=Low
Up
Down
-
-
CI1 only
counting
CI0FE=High
-
-
Up
Down
CI0FE=Low
-
-
Down
Up
CI0 and CI1
counting
CI1FE=High
Down
Up
X
X
CI1FE=Low
Up
Down
X
X
CI0FE=High
X
X
Up
Down
CI0FE=Low
X
X
Down
Up
Note: "-" means "no counting"; "X" means impossible.
Figure 9-74. Example of counter operation in encoder interface mode
CI0
CI1
UP downCount
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Figure 9-75. Example of encoder interface mode with CI0FE0 polarity inverted
CI0
CI1
UPdownCount
Slave controller
The TIMERx can be synchronized with an external trigger in several modes including the
Restart mode, the Pause mode and the event mode which is selected by the SMC field in the
TIMERx_SMCFG register. The trigger input of these modes can be selected by the TRGS
field in the TIMERx_SMCFG register, below to CI0 signal as an example.The operation
modes in the Slave Controller are described in the accompanying sections.
Restart mode
The counter and its prescaler can be reinitialized in response to a rising edge of the CI0 signal.
When a CI0 rising edge occurs, the update event software generation bit named UPG will
automatically be asserted by hardware and the trigger event flag will also be set. Then the
counter and prescaler will be reinitialized. Although the UPG bit is set to 1 by hardware, the
update event does not really occur. It depends upon whether the update event disable control
bit UPDIS is set to 1 or not. If UPDIS is set to 1 to disable the update event to occur, there
will no update event will be generated, however the counter and prescaler are still reinitialized
when the CI0 rising edge occurs. If the UPDIS bit in the TIMERx_CTL0 register is cleared to
enable the update event to occur, an update event will be generated together with the CI0
rising edge, then all the preloaded registers will be updated.
Figure 9-76. Control circuit in restart mode
CNT_CLK
CNT_REG 60 61 62 63 00 01 02 03 04 00 01 02 03 04
UPG
TRGIF
CI0
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Pause mode
In the Pause Mode, the selected CI0 input signal level is used to control the counter start/stop
operation. The counter starts to count when the selected CI0 signal is at a high level and
stops counting when the CI0 signal is changed to a low level, here the counter will maintain
its present value and will not be reset.
Figure 9-77. Control circuit in pause mode
CNT_CLK
CNT_REG 52 53 54 55 57 58 59
CI0
TRGIF
CEN
56
Event mode
After the counter is disabled to count, the counter can resume counting when a CI0 rising
edge signal occurs. When an CI0 rising edge occurs, the counter will start to count from the
current value in the counter. Note that the CI0 signal is only used to enable the counter to
resume counting and has no effect on controlling the counter to stop counting.
Figure 9-78. Control circuit in event mode
CNT_CLK
CNT_REG
CI0
TRGIF
56 57 58 59 5A 5B 5C 5D 5E 5F
CEN
Timer interconnection
The timers can be internally connected together for timer chaining or synchronization. This
can be implemented by configuring one timer to operate in the Master mode while configuring
another timer to be in the Slave mode. The following figures present several examples of
trigger selection for the master and slave modes.
Figure below shows the timer x trigger selection when it is configured in slave mode.
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Figure 9-79. Master/Slave mode timer example
TIMER1
TIMER 0
Prescaler Counter
Master
mode
control
TIMER 14
Prescaler Counter
Master
mode
control
TIMER 2
Prescaler Counter
Master
mode
control
Trigger
selection
ITI0
ITI1
ITI2
CI0F_ED
CI0EP0
CI1EP1
ETIF
TRGS
trigger
selection
Slave mode
control Prescaler Counter
TRGO
TRGO
TRGO
Timer debug mode
When the Cortex™-M3 halted, and the DBG_TIMERx_STOP configuration bit in DBG module
set to 1, the TIMERx counter stops.
9.2.4. TIMER1/TIMER2 registers
Control register 0 (TIMERx_CTL0)
Address offset: 0x00
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
CKDIV[1:0]
ARSE
CAM[1:0]
DIR
SPM
UPS
UPDIS
CEN
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
15:10
Reserved
Must be kept at reset value
9:8
CKDIV[1:0]
Clock division
The CKDIV bits can be configured by software to specify division ratio between the
timer clock (TIMER_CK) and the dead-time and sampling clock (DTS), which is used
by the dead-time generators and the digital filters.
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00: fDTS=fTIMER_CK
01: fDTS=fTIMER_CK /2
10: fDTS= fTIMER_CK /4
11: Reserved
7
ARSE
Auto-reload shadow enable
0: The shadow register for TIMERx_CAR register is disabled
1: The shadow register for TIMERx_CAR register is enabled
6:5
CAM[1:0]
Counter aligns mode selection
00: No center-aligned mode (edge-aligned mode). The direction of the counter is
specified by the DIR bit.
01: Center-aligned and counting down assert mode. The counter counts up and down
alternatively. Output compare interrupt flags of channels, which are configured in
output mode (CHxMS=00 in TIMERx_CHCTLx register), are set only when the
counter is counting down.
10: Center-aligned and counting up assert mode. The counter counts up and down
alternatively. Output compare interrupt flags of channels, which are configured in
output mode (CHxMS=00 in TIMERx_CHCTLx register), are set only when the
counter is counting up.
11: Center-aligned and counting up/down assert mode. The counter counts up and
down alternatively. Output compare interrupt flags of channels, which are configured
in output mode (CHxMS=00 in TIMERx_CHCTLx register), are set only when the
counter is counting both up and down.
The counter should be disabled when switches from edge-aligned mode to center-
aligned mode.
4
DIR
Direction
0: Count up
1: Count down
This bit is read only when the timer is configured in Center-aligned mode or Encoder
mode.
3
SPM
Single pulse mode.
0: Counter continues after update event.
1: The CEN is cleared by hardware and the counter stops at update event.
2
UPS
Update source
This bit is used to select the update event sources.
0: When enabled, any of the following events generate an update interrupt or DMA
request:
– The UPG bit is set
– The counter generates an overflow or underflow event
– The slave mode controller generates an update event.
1: When enabled, only counter overflow/underflow generates an update interrupt or
DMA request.
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1
UPDIS
Update disable.
This bit is used to enable or disable the update event generation.
0: update event enable. The update event is generate and the buffered registers are
loaded with their preloaded values when one of the following events occurs:
– The UPG bit is set
– The counter generates an overflow or underflow event
– The slave mode controller generates an update event.
1: update event disable. The buffered registers keep their value, while the counter
and the prescaler are reinitialized if the UPG bit is set or if the slave mode controller
generates a hardware reset event.
0
CEN
Counter enable
0: Counter disable
1: Counter enable
The CEN bit must be set by software when timer works in external clock, pause mode
and encoder mode. While in event mode, the hardware can set the CEN bit
automatically.
Control register 1 (TIMERx_CTL1)
Address offset: 0x04
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
TI0S
MMC[2:0]
DMAS
Reserved
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
15:8
Reserved
Must be kept at reset value
7
TI0S
Channel 0 trigger input selection
0: The TIMERx_CH0 pin input is selected as channel 0 trigger input.
1: The result of combinational XOR of TIMERx_CH0, CH1 and CH2 pins is selected
as channel 0 trigger input.
6:4
MMC[2:0]
Master mode control
These bits control the selection of TRGO signal, which is sent in master mode to
slave timers for synchronization function.
000: Reset. When the UPG bit in the TIMERx_SWEVG register is set or a reset is
generated by the slave mode controller, a TRGO pulse occurs. And in the latter
case, the signal on TRGO is delayed compared to the actual reset.
001: Enable. This mode is useful to start several timers at the same time or to
control a window in which a slave timer is enabled. In this mode the master mode
controller selects the counter enable signal TIMERx_EN as TRGO. The counter
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231
enable signal is set when CEN control bit is set or the trigger input in pause mode is
high. There is a delay between the trigger input in pause mode and the TRGO
output, except if the master-slave mode is selected.
010: Update. In this mode the master mode controller selects the update event as
TRGO.
011: Capture/compare pulse.In this mode the master mode controller generates a
TRGO pulse when a capture or a compare match occurred.
100: Compare.In this mode the master mode controller selects the O0CPRE signal
is used as TRGO
101: Compare.In this mode the master mode controller selects the O1CPRE signal
is used as TRGO
110: Compare.In this mode the master mode controller selects the O2CPRE signal
is used as TRGO
111: Compare.In this mode the master mode controller selects the O3CPRE signal
is used as TRGO
3
DMAS
DMA request source selection
0: DMA request of channel x is sent when capture/compare event occurs.
1: DMA request of channel x is sent when update event occurs.
2:1
Reserved
Must be kept at reset value.
Slave mode configuration register (TIMERx_SMCFG)
Address offset: 0x08
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
ETP
SMC1
ETPSC[1:0]
ETFC[3:0]
MSM
TRGS[2:0]
OCRC
SMC[2:0]
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
15
ETP
External trigger polarity
This bit specifies the polarity of ETI signal
0: ETI is active at high level or rising edge.
1: ETI is active at low level or falling edge.
14
SMC1
Part of SMC for enable External clock mode1
In external clock mode 1, the counter is clocked by any active edge on the ETIF
signal.
0: External clock mode 1 disabled
1: External clock mode 1 enabled.
Setting the SMC1 bit has the same effect as selecting external clock mode 0 with
TRGI connected to ETIF (SMC=111 and TRGS =111).
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232
It is possible to simultaneously use external clock mode 1 with the reset mode,
pause mode or event mode. But the TRGS bits must not be 111 in this case.
The external clock input will be ETIF if external clock mode 0 and external clock
mode 1 are enabled at the same time.
13:12
ETPSC[1:0]
External trigger prescaler
The frequency of external trigger signal ETI must not be at higher than 1/4 of
TIMERx_CK frequency. When the external trigger signal is a fast clocks, the
prescaler can be enabled to reduce ETI frequency.
00: Prescaler disable
01: ETI frequency will be divided by 2
10: ETI frequency will be divided by 4
11: ETI frequency will be divided by 8
11:8
ETFC[3:0]
External trigger filter control
An event counter is used in the digital filter, in which a transition on the output
occurs after N input events. This bit-field specifies the frequency used to sample
ETI signal and the length of the digital filter applied to ETI.
0000: Filter disalble. fSAMP=fDTS, N=1.
0001: fSAMP= fTIMER_CK, N=2.
0010: fSAMP= fTIMER_CK, N=4.
0011: fSAMP= fTIMER_CK, N=8.
0100: fSAMP=fDTS/2, N=6.
0101: fSAMP=fDTS/2, N=8.
0110: fSAMP=fDTS/4, N=6.
0111: fSAMP=fDTS/4, N=8.
1000: fSAMP=fDTS/8, N=6.
1001: fSAMP=fDTS/8, N=8.
1010: fSAMP=fDTS/16, N=5.
1011: fSAMP=fDTS/16, N=6.
1100: fSAMP=fDTS/16, N=8.
1101: fSAMP=fDTS/32, N=5.
1110: fSAMP=fDTS/32, N=6.
1111: fSAMP=fDTS/32, N=8.
7
MSM
Master-slave mode
The effect of an event on the trigger input is delayed in this mode to allow a perfect
synchronization between the current timer and its slaves through TRGO. If we want
to synchronize several timers on a single external event, this mode can be used.
0: Master-slave mode disable
1: Master-slave mode enable
6:4
TRGS[2:0]
Trigger selection
This bit-field specifies which signal is selected as the trigger input, which is used to
synchronize the counter.
000: Internal trigger input 0 (ITI0)
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233
001: Internal trigger input 1 (ITI1)
010: Internal trigger input 2 (ITI2)
011: Internal trigger input 3 (ITI3)
100: CI0 edge flag (CI0F_ED)
101: Filtered channel 0 input (CI0FE0)
110: Filtered channel 1 Input (CI1FE1)
111: External trigger input (ETIF)
These bits must not be changed when slave mode is enabled.
Slave TIMER
ITI0
(TRGS =
000)
ITI1
(TRGS =
001)
ITI2
(TRGS =
010)
ITI3
(TRGS =
011)
TIMER1
TIMER0
TIMER14
TIMER2
Reserved
TIMER2
TIMER0
TIMER1
TIMER14
Reserved
3
OCRC
OCPRE clear source selection
0: OCPRE_CLR_INT is connected to the OCPRE_CLR input
1: OCPRE_CLR_INT is connected to ETIF
2:0
SMC[2:0]
Slave mode control
000: Disable mode.The prescaler is clocked directly by the internal clock when CEN
bit is set high.
001: Quadrature decodermode 0.The counter counts on CI1FE1 edge, while the
direction depends on CI0FE0 level.
010: Quadrature decoder mode 1.The counter counts on CI0FE0 edge, while the
direction depends on CI1FE1 level.
011: Quadrature decoder mode 2.The counter counts on both CI0FE0 and CI1FE1
edge, while the direction depends on each other.
100: RestartMode.The counter is reinitialized and the shadow registers are updated
on the rising edge of the selected trigger input.
101: Pause Mode.The trigger input enables the counter clock when it is high and
disables the counter when it is low.
110: Event Mode.A rising edge of the trigger input enables the counter. The counter
cannot be disabled by the slave mode controller.
111: External Clock Mode 0.The counter counts on the rising edges of the selected
trigger.
Because CI0F_ED outputs 1 pulse for each transition on CI0F, and the pause mode
checks the level of the trigger signal, when CI0F_ED is selected as the trigger input,
the pause mode must not be used.
DMA and interrupt enable register (TIMERx_DMAINTEN)
Address offset: 0x0C
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
GD32F1x0 User Manual
234
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Res
TRGDEN
Res
CH3DEN
CH2DEN
CH1DEN
CH0DEN
UPDEN
Res
TRGIE
Res
CH3IE
CH2IE
CH1IE
CH0IE
UPIE
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
15
Reserved
Must be kept at reset value.
14
TRGDEN
Trigger DMA request enable
0: Trigger DMA request disabled
1: Trigger DMA request enabled
13
Reserved
Must be kept at reset value
12
CH3DEN
Channel 3 Capture/Compare DMA request enable
0: Channel 3 Capture/Compare DMA request disabled
1: Channel 3 Capture/Compare DMA request enabled
11
CH2DEN
Channel 2 Capture/Compare DMA request enable
0: Channel 2Capture/Compare DMA request disabled
1: Channel 2 Capture/Compare DMA request enabled
10
CH1DEN
Channel 1 Capture/Compare DMA request enable
0: Channel 1Capture/Compare DMA request disabled
1: Channel 1 Capture/Compare DMA request enabled
9
CH0DEN
Channel 0 Capture/Compare DMA request enable
0: Channel 0 Capture/Compare DMA request disabled
1: Channel 0 Capture/Compare DMA request enabled
8
UPDEN
Update DMA request enable
0: Update DMA request disabled
1: Update DMA request enabled
7
Reserved
Must be kept at reset value
6
TRGIE
Trigger interrupt enable
0: Trigger interrupt disabled
1: Trigger interrupt enabled
5
Reserved
Must be kept at reset value.
4
CH3IE
Channel 3 Capture/Compare interrupt enable
0: Channel 3 Capture/Compare interrupt disabled
1: Channel 3 Capture/Compare interrupt enabled
3
CH2IE
Channel 2 Capture/Compare interrupt enable
0: Channel 2 Capture/Compare interrupt disabled
1: Channel 2 Capture/Compare interrupt enabled
2
CH1IE
Channel 1 Capture/Compare interrupt enable
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235
0: Channel 1 Capture/Compare interrupt disabled
1: Channel 1 Capture/Compare interrupt enabled
1
CH0IE
Channel 0 Capture/Compare interrupt enable
0: Channel 0 Capture/Compare interrupt disabled
1: Channel 0 Capture/Compare interrupt enabled
0
UPIE
Update Capture/Compare interrupt enable
0: Update Capture/Compare interrupt disabled
1: Update Capture/Compare interrupt enabled
Interrupt flag register (TIMERx_INTF)
Address offset: 0x10
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
CH3OF
CH2OF
CH1OF
CH0OF
Reserved.
TRGIF
Res.
CH3IF
CH2IF
CH1IF
CH0IF
UPIF
rc_w0
rc_w0
rc_w0
rc_w0
rc_w0
rc_w0
rc_w0
rc_w0
rc_w0
rc_w0
Bits
Fields
Descriptions
15:13
Reserved
Must be kept at reset value
12
CH3OF
Channel 3 Capture overflow flag
Refer to CH0OF description
11
CH2OF
Channel 2 Capture overflow flag
Refer to CH0OF description
10
CH1OF
Channel 1 Capture overflow flag
Refer to CH0OF description
9
CH0OF
Channel 0 Capture overflow flag
When channel 0 is configured in input mode, this flag is set by hardware when a
capture event occurs while CH0IF flag has already been set. This flag is cleared by
software.
0: No Capture overflow interrupt occurred
1: Capture overflow interrupt occurred
8:7
Reserved
Must be kept at reset value
6
TRGIF
Trigger interrupt flag
This flag is set by hardware on trigger event and cleared by software. When the
slave mode controller is enabled in all modes but pause mode, an active edge on
TRGI input generates a trigger event. When the slave mode controller is enabled in
pause mode both edges on TRGI input generates a trigger event.
0: No trigger event occurred
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236
1: Trigger interrupt occurred
5
Reserved
Must be kept at reset value
4
CH3IF
Channel 3 Capture/Compare interrupt enable
Refer to CH0IF description
3
CH2IF
Channel 2 Capture/Compare interrupt enable
Refer to CH0IF description
2
CH1IF
Channel 1 Capture/Compare interrupt enable
Refer to CH0IF description
1
CH0IF
Channel 0 Capture/Compare interrupt flag
This flag is set by hardware and cleared by software. When channel 0 is in input
mode, this flag is set when a capture event occurs. When channel 0 is in output
mode, this flag is set when a compare event occurs.
0: No Channel 0 interrupt occurred
1: Channel 0 interrupt occurred
0
UPIF
Update interrupt flag
This bit is set by hardware on an update event and cleared by software.
0: No update interrupt occurred
1: Update interrupt occurred
Software event generation register (TIMERx_SWEVG)
Address offset: 0x14
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
BRKG
TRGG
Res.
CH3G
CH2G
CH1G
CH0G
UPG
w
w
w
w
w
w
w
Bits
Fields
Descriptions
15:8
Reserved
Must be kept at reset value
7
BRKG
Break event generation
This bit is set by software and cleared by hardware automatically. When this bit is
set, the POEN bit is cleared and BRKIF flag is set, related interrupt or DMA transfer
can occur if enabled.
0: No generate a break event
1: Generate a break event
6
TRGG
Trigger event generation
This bit is set by software and cleared by hardware automatically. When this bit is
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237
set, the TRGIF flag in TIMERx_INTF register is set,related interrupt or DMA transfer
can occur if enabled.
0: No generate a trigger event
1: Generate a trigger event
5
Reserved
Must be kept at reset value
4
CH3G
Channel 3’s capture or compare event generation
Refer to CH0G description
3
CH2G
Channel 2’s capture or compare event generation
Refer to CH0G description
2
CH1G
Channel 1’s capture or compare event generation
Refer to CH0G description
1
CH0G
Channel 0’s capture or compare event generation
This bit is set by software in order to generate a capture or compare event in
channel 0, it is automatically cleared by hardware. When this bit is set, the CH0IF
flag is set, the corresponding interrupt or DMA request is sent if enabled. In
addition, if channel 0 is configured in input mode, the current value of the counter is
captured in TIMER0_CH0CV register, and the CH0OF flag is set if the CH0IF flag
was already high.
0: No generate a channel 0 capture or compare event
1: Generate a channel 0 capture or compare event
0
UPG
This bit can be set by software, and cleared by hardware automatically. When this
bit is set, the counter is cleared if the center-aligned or upcounting mode is
selected, else (downcounting)it takes the auto-reload value. The prescaler counter
is cleared at the same time.
0: No generate an update event
1: Generate an update event
Channel control register 0 (TIMERx_CHCTL0)
Address offset: 0x18
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
CH1COM
CEN
CH1COMCTL[
2:0]
CH1COM
SEN
CH1COM
FEN
CH1MS[1
:0]
CH0COM
CEN
CH0COMCTL[
2:0]
CH0COM
SEN
CH0COM
FEN
CH0MS[1
:0]
CH1CAPFLT[3:0]
CH1CAPPSC[1:0]
CH0CAPFLT[3:0]
CH0CAPPSC[1:0]
rw
rw
rw
rw
rw
rw
Output compare mode:
Bits
Fields
Descriptions
GD32F1x0 User Manual
238
15
CH1COMCEN
Channel 1 output compare clear enable.
Refer to CH0COMCEN description.
14:12
CH1COMCTL[2:0]
Channel 1 output compare mode
Refer to CH0COMCTL description.
11
CH1COMSEN
Channel 1 output compare shadow enable
Refer to CH0COMSEN description.
10
CH1COMFEN
Channel 1 output compare fast enable
Refer to CH0COMFEN description.
9:8
CH1MS[1:0]
Channel 1 mode selection
This bit-field specifies the direction of the channel and the input signal selection.
This bit-field is writable only when the channel is OFF (CH1EN bit in
TIMERx_CHCTL2 register is reset).
00: Channel 1 is configured as output
01: Channel 1 is configured as input, IC1 is connected to CI1FE1
10: Channel 1 is configured as input, IC1 is connected to CI0FE1
11: Channel 1 is configured as input, IC1 is connected to ITS. This mode is
working only if an internal trigger input is selected through TRGS bits in
TIMERx_SMCFG register.
7
CH0COMCEN
Channel 0 output compare clear enable.
When this bit is set, the O0CPRE signal is cleared when High level is detected on
ETIF input.
0: Channel 0 output compare clear disable
1: Channel 0 output compare clear enable
6:4
CH0COMCTL[2:0]
Channel 0 compare output control
This bit-field specifies the behavior of the output reference signal O0CPRE which
drives CH0_O and CH0_ON. O0CPRE is active high, while CH0_O and CH0_ON
active level depends on CH0P and CH0NP bits.
000: Frozen.The O0CPRE signal keep stable, independent of the comparison
between the output compare register TIMERx_CH0CV and the counter.
001: Set high on match.O0CPRE signal is forced high when the counter matches
the output compare register TIMERx_CH0CV.
010: Set low on match. O0CPRE signal is forced low when the counter matches
the c output compare register TIMERx_CH0CV.
011: Toggle on match. O0CPRE toggles when the counter matches the c output
compare register TIMERx_CH0CV.
100: Force low. O0CPRE is forced low level.
101: Force high. O0CPRE is forced high level.
110: PWM mode 0. When counting up, O0CPRE is high as long as the counter is
smaller than TIMERx_CH0CV else low. When counting down, O0CPRE is low as
long as the counter is larger than TIMERx_CH0CV else high.
111: PWM mode 1. When counting up, O0CPRE is low as long as the counter is
GD32F1x0 User Manual
239
smaller than TIMERx_CH0CV else high. When counting down, O0CPRE is high
as long as the counter is larger than TIMERx_CH0CV else low.
When configured in PWM mode, the OCPRE level changes only when the output
compare mode switches from “frozen” mode to “PWM” mode or when the result of
the comparison changes.
This bit cannot be modified when PROT[1:0] bit-filed in TIMERx_CCHP register is
11 and CH0MS bit-filed is 00.
3
CH0COMSEN
Channel 0 output compare shadow enable
When this bit is set, the shadow register of TIMERx_CH0CV register, which
updates at each update event will be enabled.
0: Channel 0 output compare shadow disable
1: Channel 0 output compare shadow enable
The PWM mode can be used without validating the shadow register only in one
pulse mode (SPM bit set in TIMERx_CTL0 register is set).
This bit cannot be modified when PROT[1:0] bit-filed in TIMERx_CCHP register is
11 and CH0MS bit-filed is 00.
2
CH0COMFEN
Channel 0 output compare fast enable
When this bit is set, the effect of an event on the trigger in input on the
capture/compare output will be accelerated if the channel is configured in PWM0
or PWM1 mode. The output channel will treat an active edge on the trigger input
as a compare match, and CH0_O is set to the compare level independently from
the result of the comparison.
0: Channel 0 output compare fast disable. The minimum delay from an edge on
the trigger input to activate CH0_O output is 5 clock cycles.
1: Channel 0 output compare fast enable. The minimum delay from an edge on
the trigger input to activate CH0_O output is 3 clock cycles.
1:0
CH0MS[1:0]
Channel 0 mode selection
This bit-field specifies the direction of the channel and the input signal selection.
This bit-field is writable only when the channel is OFF (CH0EN bit in
TIMERx_CHCTL2 register is reset).
00: Channel 0 is configured as output
01: Channel 0 is configured as input, IC0 is connected to CI0FE0
10: Channel 0 is configured as input, IC0 is connected to CI1FE0
11: Channel 0 is configured as input, IC0 is connected to ITS. This mode is
working only if an internal trigger input is selected through TRGS bits in
TIMERx_SMCFG register.
Input capture mode:
Bits
Fields
Descriptions
15:12
CH1CAPFLT[3:0]
Channel 1 input capture filter control
Refer to CH0CAPFLT description
GD32F1x0 User Manual
240
11:10
CH1CAPPSC[1:0]
Channel 1 input capture prescaler
Refer to CH0CAPPSC description
9:8
CH1MS[1:0]
Channel 1 mode selection
This bit-field specifies the direction of the channel and the input signal selection.
This bit-field is writable only when the channel is OFF (CH1EN bit in
TIMERx_CHCTL2 register is reset).
00: Channel 1 is configured as output
01: Channel 1 is configured as input, IC1 is connected to CI1FE1
10: Channel 1 is configured as input, IC1 is connected to CI0FE1
11: Channel 1 is configured as input, IC1 is connected to ITS. This mode is
working only if an internal trigger input is selected through TRGS bits in
TIMERx_SMCFG register.
7:4
CH0CAPFLT[3:0]
Channel 0 input capture filter control
An event counter is used in the digital filter, in which a transition on the output
occurs after N input events. This bit-field specifies the frequency used to sample
CI0 input signal and the length of the digital filter applied to CI0.
0000: Filter disable, fSAMP=fDTS, N=1
0001: fSAMP= fTIMER_CK, N=2
0010: fSAMP= fTIMER_CK, N=4
0011: fSAMP= fTIMER_CK, N=8
0100: fSAMP=fDTS/2, N=6
0101: fSAMP=fDTS/2, N=8
0110: fSAMP=fDTS/4, N=6
0111: fSAMP=fDTS/4, N=8
1000: fSAMP=fDTS/8, N=6
1001: fSAMP=fDTS/8, N=8
1010: fSAMP=fDTS/16, N=5
1011: fSAMP=fDTS/16, N=6
1100: fSAMP=fDTS/16, N=8
1101: fSAMP=fDTS/32, N=5
1110: fSAMP=fDTS/32, N=6
1111: fSAMP=fDTS/32, N=8
3:2
CH0CAPPSC[1:0]
Channel 0 input capture prescaler
This bit-field specifies the ratio of the prescaler on channel 0 input.The prescaler is
reset when CH0EN bit in TIMERx_CHCTL2 register is reset.
00: prescaler disable, capture is done on each channel input edge
01: Capture is done every 2 channel input edges
10: Capture is done every 4 channel input edges
11: Capture is done every 8 channel input edges
1:0
CH0MS[1:0]
Channel 0 mode selection
This bit-field specifies the direction of the channel and the input signal selection.
This bit-field is writable only when the channel is OFF (CH0EN bit in
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241
TIMERx_CHCTL2 register is reset).
00: Channel 0 is configured as output
01: Channel 0 is configured as input, IC0 is connected to CI0FE0
10: Channel 0 is configured as input, IC0 is connected to CI1FE0
11: Channel 0 is configured as input, IC0 is connected to ITS. This mode is
working only if an internal trigger input is selected through TRGS bits in
TIMERx_SMCFG register.
Channel control register 1 (TIMERx_CHCTL1)
Address offset: 0x1C
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
CH3COM
CEN
CH3COMCTL[
2:0]
CH3COM
SEN
CH3COM
FEN
CH3MS[1
:0]
CH2COM
CEN
CH2COMCTL[
2:0]
CH2COM
SEN
CH2COM
FEN
CH2MS[1
:0]
CH3CAPFLT[3:0]
CH3CAPPSC[1:0]
CH2CAPFLT[3:0]
CH2CAPPSC[1:0]
rw
rw
rw
rw
rw
rw
Output compare mode:
Bits
Fields
Descriptions
15
CH3COMCEN
Channel 3 output compare clear enable
Refer to CH0COMCEN description
14:12
CH3COMCTL[2:0]
Channel 3 compare output control
Refer to CH0COMCTL description
11
CH3COMSEN
Channel 3 output compare shadow enable
Refer to CH0COMSEN description
10
CH3COMFEN
Channel 3 output compare fast enable
Refer to CH0COMFEN description
9:8
CH3MS[1:0]
Channel 3 mode selection
This bit-field specifies the direction of the channel and the input signal selection.
This bit-field is writable only when the channel is OFF (CH3EN bit in
TIMERx_CHCTL2 register is reset).
00: channel 3 is configured as output
01: Channel 3 is configured as input, IC3 is connected to CI3FE3
10: Channel 3 is configured as input, IC3 is connected to CI2FE3
11: channel 3 is configured as input, IC3 is connected to ITS. This mode is
working only if an internal trigger input is selected through TRGS bits in
TIMERx_SMCFG register.
7
CH2COMCEN
Channel 2 output compare clear enable
Refer to CH0COMCEN description
GD32F1x0 User Manual
242
6:4
CH2COMCTL[2:0]
Channel 2 compare output control
Refer to CH0COMCTL description
3
CH2COMSEN
Channel 2 output compare shadow enable
Refer to CH0COMSEN description
2
CH2COMFEN
Channel 2 output compare fast enable
Refer to CH0COMFEN description
1:0
CH2MS[1:0]
Channel 2 mode selection
This bit-field specifies the direction of the channel and the input signal selection.
This bit-field is writable only when the channel is OFF (CH2EN bit in
TIMERx_CHCTL2 register is reset).
00: Channel 2 is configured as output
01: Channel 2 is configured as input, IC2 is connected to CI2FE2
10: Channel 2 is configured as input, IC2 is connected to CI3FE2
11: Channel 2 is configured as input, IC2 is connected to ITS. This mode is
working only if an internal trigger input is selected through TRGS bits in
TIMERx_SMCFG register.
Input capture mode:
Bits
Fields
Descriptions
15:12
CH3CAPFLT[3:0]
Channel 3 input capture filter control
Refer to CH0CAPFLT description
11:10
CH3CAPPSC[1:0]
Channel 3 input capture prescaler
Refer to CH0CAPPSC description
9:8
CH3MS[1:0]
Channel 3 mode selection
This bit-field specifies the direction of the channel and the input signal selection.
This bit-field is writable only when the channel is OFF (CH3EN bit in
TIMERx_CHCTL2 register is reset).
00: Channel 3 is configured as output
01: Channel 3 is configured as input, IC3 is connected to CI3FE3
10: Channel 3 is configured as input, IC3 is connected to CI2FE3
11: Channel 3 is configured as input, IC3 is connected to ITS. This mode is
working only if an internal trigger input is selected through TRGS bits in
TIMERx_SMCFG register.
7:4
CH2CAPFLT[3:0]
Channel 2 input capture filter control
Refer to CH0CAPFLT description
3:2
CH2CAPPSC[1:0]
Channel 2 input capture prescaler
Refer to CH0CAPPSC description
1:0
CH2MS[1:0]
Channel 2 mode selection
This bit-field specifies the direction of the channel and the input signal selection.
GD32F1x0 User Manual
243
This bit-field is writable only when the channel is OFF (CH2EN bit in
TIMERx_CHCTL2 register is reset).
00: Channel 2 is configured as output
01: Channel 2 is configured as input, IC2 is connected to CI2FE2
10: Channel 2 is configured as input, IC2 is connected to CI3FE2
11: Channel 2 is configured as input, IC2 is connected to ITS. This mode is
working only if an internal trigger input is selected through TRGS bits in
TIMERx_SMCFG register.
Channel control register 2 (TIMERx_CHCTL2)
Address offset: 0x20
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
CH3NP
Res.
CH3P
CH3EN
CH2NP
Res.
CH2P
CH2EN
CH1NP
Res.
CH1P
CH1EN
CH0NP
Res.
CH0P
CH0EN
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
15
CH3NP
Channel 3 complementary output polarity
Refer to CH0NP description
14
Reserved
Must be kept at reset value
13
CH3P
Channel 3 polarity
Refer to CH0P description
12
CH3EN
Channel 3 enable
Refer to CH0EN description
11
CH2NP
Channel 2 complementary output polarity
Refer to CH0NP description
10
Reserved
Must be kept at reset value
9
CH2P
Channel 2 polarity
Refer to CH0P description
8
CH2EN
Channel 2 enable
Refer to CH0EN description
7
CH1NP
Channel 1 complementary output polarity
Refer to CH0NP description
6
Reserved
Must be kept at reset value
5
CH1P
Channel 1 polarity
GD32F1x0 User Manual
244
Refer to CH0P description
4
CH1EN
Channel 1 enable
Refer to CH0EN description
3
CH0NP
Channel 0 complementary output polarity
Channel 0 configured as output
CH0NP need to be set to 0.
Channel 0 configured as input
In conjunction with CH0P, this bit is used to define the polarity of CI0.
2
Reserved
Must be kept at reset value
1
CH0P
Channel 0 polarity
When channel 0 is configured in output mode, this bit specifies the output
signal polarity.
0: Channel 0 active high
1: Channel 0 active low
When channel 0 is configured in input mode, this bit specifies the CI0 signal
polarity.
[CH0NP, CH0P] will selete the active trigger or capture polarity for CI0FE0 or
CI1FE0.
[CH0NP==0, CH0P==0]: CIxFE0’s rising edge is the active signal for capture or
trigger operation in slave mode. And CIxFE1 will not be inverted.
[CH0NP==0, CH0P==1]: CIxFE0’s falling edge is the active signal for capture or
trigger operation in slave mode. And CIxFE1 will be inverted.
[CH0NP==1, CH0P==0]: Reserved.
[CH0NP==1, CH0P==1]: CIxFE0’s falling and rising edge are both the active signal
for capture or trigger operation in slave mode. And CIxFE0 will be not inverted.
This bit cannot be modified when PROT[1:0] bit-filed in TIMERx_CCHP register is 11
or 10.
0
CH0EN
Channel 0 enable
When channel 0 is configured in input mode, setting this bit enables CH0_O signal in
active state. When channel 0 is configured in output mode, setting this bit enables the
capture event in channel 0.
0: Channel 0 disabled.
1: Channel 0 enabled.
Counter register (TIMERx_CNT)
Address offset: 0x24
Reset value: 0x0000
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
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CNT[31:16] TIMER1 ONLY
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
CNT[15:0]
rw
Bits
Fields
Descriptions
31:16
CNT[31:16]
This bit-filed indicates the current counter value. Writing to this bit-filed can change
the value of the counter. Only TIMER1 has this high 16bit counter value.
15:0
CNT[15:0]
This bit-filed indicates the current counter value. Writing to this bit-filed can change
the value of the counter.
Prescaler register (TIMERx_PSC)
Address offset: 0x28
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
PSC[15:0]
rw
Bits
Fields
Descriptions
15:0
PSC[15:0]
Prescaler value of the counter clock
The PSC clock is divided by (PSC+1) to generate the counter clock. The
value of this bit-filed will be loaded to the corresponding shadow register at
every update event.
Counter auto reload register (TIMERx_CAR)
Address offset: 0x2C
Reset value: 0x0000
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
CAR [31:16] TIMER1 ONLY
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
CAR [15:0]
rw
Bits
Fields
Descriptions
31:16
CAR [31:16]
Counter auto reload value. Only TIMER1 has this high 16bit counter value.
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246
15:0
CAR[15:0]
Counter auto reload value
This bit-filed specifies the auto reload value of the counter.
Channel 0 capture/compare value register (TIMERx_CH0CV)
Address offset: 0x34
Reset value: 0x0000
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
CH0VAL [31:16] TIMER1 ONLY
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
CH0VAL[15:0]
rw
Bits
Fields
Descriptions
31:16
CH0VAL
[31:16]
Capture or compare value of channel 0. Only TIMER1 has this high 16bit counter
value.
15:0
CH0VAL
[15:0]
Capture or compare value of channel 0
When channel 0 is configured in input mode, this bit-filed indicates the counter
value corresponding to the last capture event. And this bit-filed is read-only.
When channel 0 is configured in output mode, this bit-filed contains value to be
compared to the counter. When the corresponding shadow register is enabled, the
shadow register updates every update event.
Channel 1 capture/compare value register (TIMERx_CH1CV)
Address offset: 0x38
Reset value: 0x0000
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
CH2VAL [31:16] TIMER1 ONLY
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
CH1VAL [15:0]
rw
Bits
Fields
Descriptions
31:16
CH1VAL
[31:16]
Capture or compare value of channel 1. Only TIMER1 has this high 16bit counter
value.
15:0
CH1VAL
[15:0]
Capture or compare value of channel 1
When channel 1 is configured in input mode, this bit-filed indicates the counter
GD32F1x0 User Manual
247
value corresponding to the last capture event. And this bit-filed is read-only.
When channel 1 is configured in output mode, this bit-filed contains value to be
compared to the counter. When the corresponding shadow register is enabled, the
shadow register updates every update event.
Channel 2 capture/compare value register (TIMERx_CH2CV)
Address offset: 0x3C
Reset value: 0x0000
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
CH2VAL [31:16] TIMER1 ONLY
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
CH2VAL [15:0]
rw
Bits
Fields
Descriptions
31:16
CH2VAL[31:16]
Capture or compare value of channel 2. Only TIMER1 has this high 16bit counter
value.
15:0
CH2VAL[15:0]
Capture or compare value of channel 2
When channel 2 is configured in input mode, this bit-filed indicates the counter
value corresponding to the last capture event. And this bit-filed is read-only.
When channel 2 is configured in output mode, this bit-filed contains value to be
compared to the counter. When the corresponding shadow register is enabled, the
shadow register updates every update event.
Channel 3 capture/compare value register (TIMERx_CH3CV)
Address offset: 0x40
Reset value: 0x0000
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
CH3VAL [31:16] TIMER1 ONLY
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
CH3VAL [15:0]
rw
Bits
Fields
Descriptions
31:16
CH3VAL
[31:16]
Capture or compare value of channel 3. Only TIMER1 has this high 16bit counter
value.
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248
15:0
CH3VAL
[15:0]
Capture or compare value of channel 3
When channel 3 is configured in input mode, this bit-filed indicates the counter
value corresponding to the last capture event. And this bit-filed is read-only.
When channel 3 is configured in output mode, this bit-filed contains value to be
compared to the counter. When the corresponding shadow register is enabled, the
shadow register updates every update event.
DMA configuration register (TIMERx_DMACFG)
Address offset: 0x48
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
DMATC[4:0]
Reserved
DMATA[4:0]
rw
rw
Bits
Fields
Descriptions
15:14
Reserved
Must be kept at reset value
12:8
DMATC[4:0]
DMA transfer count
When register access are done through the TIMERx_DMATB address, this 5-bit bit-
field specifies the number of transfers.
7:5
Reserved
Must be kept at reset value
4:0
DMATA[4:0]
DMA transfer access start address
When register access are done through the TIMERx_DMATB address, this bit-field
specifies the offset of the starting address from the TIMERx_CTL0 register.
DMA Transfer buffer register (TIMERx_DMATB)
Address offset: 0x4C
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
DMATB[15:0]
rw
Bits
Fields
Descriptions
15:0
DMATB[15:0]
DMA transfer
When a read or write operation is assigned to this register, the register located at
the address range (DMATA + burst counter) x 4 from TIMERx_CTL0 will be
accessed.
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249
The burst counter is calculated by hardware, and ranges from 0 to DMATC.
Configuration register (TIMERx_CFG) of GD32F170xx and GD32F190xx
devices
Address offset: 0xFC
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
CCSEL
Reserved
rw
Bits
Fields
Descriptions
15:2
Reserved
Must be kept at reset value
1
CCSEL
Write Capture/Compare register selection
This bit-field set and reset by software.
1: If write the Capture/Compare register, the write value is same as the
Capture/Compare value, the write access ignored
0: No effect
0
Reserved
Must be kept at reset value.
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9.3. Basic timer (TIMER5)
9.3.1. Introduction
The general timers (TIMER5) consist of one 16-bit counter auto reload register (TIMERx_CAR)
and several control registers. It can be used for general timer, and it is also used by
DAC(Digital to analog converter). TIMER5’s TRGO is connected to DAC which can be drived
by this trigger.
9.3.2. Main features
16-bit up auto-reload counter.
16-bit programmable prescaler that allows division of the counter clock frequency by any
factor between 1 and 65536.
Synchronization circuit to trigger the DAC.
Interrupt/DMA generated by counter overflow.
9.3.3. Function description
Figure below provides details on the internal configuration of the Basic timer.
Figure 9-80. General timer block diagram (TIMER5)
Trigger Controller
TIMER5_CK From RCU TRIGO
Prescaler
AutoReload Register
Reset, Enable, Up/Down, Count
Counter
Prescaler counter
The prescaler can divide the timer clock (TIMER_CK) to the counter clock (CNT_CLK) by any
factor between 1 and 65536. It is controlled through prescaler register (TIMERx_PSC) which
can be changed on the fly but be taken into account at the next update event.
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251
Figure 9-81. Counter timing diagram with prescaler division change from 1 to 2
TIMER_CK
CEN
CNT_CLK
CNT_REG
Reload Pulse
Prescaler CNT
Prescaler BUF
Prescaler CR
F7 F8 F9 FA FB FC 01 02 03 04
01
0 1
0 0 1 0 1 0 1 0 1
modify scaler Vaule
Figure 9-82. Counter timing diagram with prescaler division change from 1 to 4
TIMER_CK
CEN
CNT_CLK
CNT_REG
Reload Pulse
Prescaler CNT
Prescaler BUF
Prescaler CR
F7 F8 F9 FA FB FC 00 01
03
0 3
0 0 1 2 3 0 1 2 3
modify PSC Vaule
Upcounting mode
In this mode the counter counts continuously from 0 to the counter-reload value, which is
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252
defined in the TIMERx_CAR register, in a count-up direction. Once the counter reaches the
counter reload value, the counter restarts to count once again from 0. The update event is
generated at each counter overflow.
When the update event is set by the UPG bit in the TIMERx_SWEVG register, the counter
value will be initialized to 0 and generates an update event.
If set the UPDIS bit in TIMERx_CTL0 register, the update event is disabled.
When an update event occurs, all the registers (autoreload register, prescaler register) are
updated.
Clock selection
Basic timer has the unique clock source which is controlled by RCU. Counter and prescaler
counter are clocked by this internal clock TIMER_CK, except UPG is asserted. UPG’s assert
will initial counter and prescaler counter.
Figure 9-83. Control circuit in normal mode, internal clock divided by 1
TIMER_CK
CEN
CNT_CLK
CNT_REG
Reload Pulse
17 18 19 20 21 22
UPG
23 00 01 02 03 04 05 06
Timer debug mode
When the Cortex™-M3 halted, and the DBG_TIMERx_STOP configuration bit in DBG module
set to 1, the TIMERx counter stops.
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253
9.3.4. TIMER5 registers
Control register 0 (TIMERx_CTL0)
Address offset: 0x00
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
ARSE
Reserved
SPM
UPS
UPDIS
CEN
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
15:8
Reserved
Must be kept at reset value
7
ARSE
Auto-reload shadow enable
0: The shadow register for TIMERx_CAR register is disabled
1: The shadow register TIMERx_ CAR register is enabled
3
SPM
Single pulse mode.
0: Counter continues after update event.
1: The CEN is cleared by hardware and the counter stops at next update event.
2
UPS
Update source
This bit is used to select the update event sources by software.
0: When enabled, any of the following events generate an update interrupt or DMA
request:
– The UPG bit is set
– The counter generates an overflow or underflow event
– The slave mode controller generates an update event.
1: When enabled, only counter overflow/underflow generates an update interrupt or
DMA request.
1
UPDIS
Update disable.
This bit is used to enable or disable the update event generation.
0: update event enable. The update event is generate and the buffered registers are
loaded with their preloaded values when one of the following events occurs:
– The UPG bit is set
– The counter generates an overflow or underflow event
– The slave mode controller generates an update event.
1: update event disable. The buffered registers keep their value, while the counter
and the prescaler are reinitialized if the UPG bit is set or if the slave mode controller
generates a hardware reset event.
0
CEN
Counter enable
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254
0: Counter disable
1: Counter enable
The CEN bit must be set by software when timer works in external clock, pause mode
and encoder mode. While in event mode, the hardware can set the CEN bit
automatically.
Control register 1 (TIMERx_CTL1)
Address offset: 0x04
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
MMC[2:0]
Reserved
rw
Bits
Fields
Descriptions
15:7
Reserved
Must be kept at reset value
6:4
MMC[2:0]
Master mode control
These bits control the selection of TRGO signal, which is sent in master mode to
slave timers for synchronization function.
000: Reset. When the UPG bit in the TIMERx_SWEVG register is set or a reset is
generated by the slave mode controller, a TRGO pulse occurs. And in the latter case,
the signal on TRGO is delayed compared to the actual reset.
001: Enable. This mode is useful to start several timers at the same time or to control
a window in which a slave timer is enabled. In this mode the master mode controller
selects the counter enable signal TIMERx_EN as TRGO. The counter enable signal
is set when CEN control bit is set or the trigger input in pause mode is high. There is
a delay between the trigger input in pause mode and the TRGO output, except if the
master-slave mode is selected.
010: Update. In this mode the master mode controller selects the update event as
TRGO.
011: Capture/compare pulse.In this mode the master mode controller generates a
TRGO pulse when a capture or a compare match occurred.
100: Compare.In this mode the master mode controller selects the O0CPRE signal is
used as TRGO
101: Compare.In this mode the master mode controller selects the O1CPRE signal is
used as TRGO
110: Compare.In this mode the master mode controller selects the O2CPRE signal is
used as TRGO
111: Compare.In this mode the master mode controller selects the O3CPRE signal is
used as TRGO
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3:0
Reserved
Must be kept at reset value
DMA and interrupt enable register (TIMERx_DMAINTEN)
Address offset: 0x0C
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
UPDEN
Reserved
UPIE
rw
rw
Bits
Fields
Descriptions
15:9
Reserved
Must be kept at reset value
8
UPDEN
Update DMA request enable
0: Update DMA request disabled
1: Update DMA request enabled
7:1
Reserved
Must be kept at reset value
0
UPIE
Update interrupt enable
0: Update interrupt disabled
1: Update interrupt enabled
Interrupt flag register (TIMERx_INTF)
Address offset: 0x10
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
UPIF
rc_w0
Bits
Fields
Descriptions
15:1
Reserved
Must be kept at reset value
0
UPIF
Update interrupt flag
This bit is set by hardware on an update event and cleared by software.
0: No update interrupt occurred
1: Update interrupt occurred
Software event generation register (TIMERx_SWEVG)
Address offset: 0x14
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256
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
UPG
w
Bits
Fields
Descriptions
15:1
Reserved
Must be kept at reset value.
0
UPG
This bit can be set by software, and cleared by hardware automatically. When this
bit is set, the counter is cleared if the center-aligned or upcounting mode is
selected, else (downcounting) it takes the auto-reload value. The prescaler counter
is cleared at the same time.
0: No generate an update event
1: Generate an update event
Counter register (TIMERx_CNT)
Address offset: 0x24
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
CNT[15:0]
rw
Bits
Fields
Descriptions
15:0
CNT[15:0]
This bit-filed indicates the current counter value. Writing to this bit-filed can change
the value of the counter.
Prescaler register (TIMERx_PSC)
Address offset: 0x28
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
PSC[15:0]
rw
Bits
Fields
Descriptions
15:0
PSC[15:0]
Prescaler value of the counter clock
The PSC clock is divided by (PSC+1) to generate the counter clock. The value of this bit-
GD32F1x0 User Manual
257
filed will be loaded to the corresponding shadow register at every update event.
Counter auto reload register (TIMERx_CAR)
Address offset: 0x2C
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
CAR[15:0]
rw
Bits
Fields
Descriptions
15:0
CAR[15:0]
Counter auto reload value
This bit-filed specifies the auto reload value of the counter.
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258
9.4. General timer (TIMER13)
9.4.1. Introduction
The general timer (TIMER13) consists of one 16-bit up -counter; one capture/compare
register (TIMERx_CHxCV), one counter auto reload register (TIMERx_CAR) and several
control registers. They can be used for a variety of purposes including general timer, input
signal pulse width measurement or output waveform generation such as output compare or
PWM output.
9.4.2. Main features
16-bit up auto-reload counter.
16-bit programmable prescaler that allows division of the counter clock frequency by any
factor between 1 and 65536.
One independent channel supports functions including input capture, compare match
output, and generation of PWM waveform (edge and center-aligned Mode).
Interrupt/DMA generation by update, input capture event, or output compare match event.
9.4.3. Function description
Figure below provides details on the internal configuration of the generic timer.
Figure 9-84. General timer block diagram (TIMER13)
CH0
Input Filter Edge
Detector Prescaler
Capture
Register
Compare
Register
Prescaler
Counter
AutoReload
Register
Output
Control
CH0
Enable
Trigger Controller
TIMER13_CK From RCU
Prescaler counter
The prescaler can divide the timer clock (TIMER_CK) to the counter clock (CNT_CLK) by any
factor between 1 and 65536. It is controlled through prescaler register (TIMERx_PSC) which
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259
can be changed on the fly but be taken into account at the next update event.
Figure 9-85. Counter timing diagram with prescaler division change from 1 to 2
TIMER_CK
CEN
CNT_CLK
CNT_REG
Reload Pulse
Prescaler CNT
Prescaler BUF
Prescaler CR
F7 F8 F9 FA FB FC 01 02 03 04
01
0 1
0 0 1 0 1 0 1 0 1
modify scaler Vaule
Figure 9-86. Counter timing diagram with prescaler division change from 1 to 4
TIMER_CK
CEN
CNT_CLK
CNT_REG
Reload Pulse
Prescaler CNT
Prescaler BUF
Prescaler CR
F7 F8 F9 FA FB FC 00 01
03
0 3
0 0 1 2 3 0 1 2 3
modify PSC Vaule
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260
Upcounting mode
In this mode the counter counts continuously from 0 to the counter-reload value. Once the
counter reaches the counter reload value, the counter restarts to count once again from 0.
The update event is generated at each counter overflow.
When the update event is set by the UPG bit in the TIMERx_SWEVG register, the counter
value will be initialized to 0 and generates an update event.
If set the UPDIS bit in TIMERx_CTL0 register, the update event is disabled.
When an update event occurs, all the registers (autoreload register, prescaler register) are
updated.
The following figures show some examples of the counter behavior for different clock
frequencies when TIMERx_CAR=0x63.
Figure 9-87. Counter timing diagram, internal clock divided by 1
TIMER_CK
CEN
CNT_CLK
CNT_REG
overflow
5E 5F 60 61 62 63 00 01 02 03 04 05 06 07
Update event (UPE)
Update interrupt flag (UPIF)
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261
Figure 9-88. Counter timing diagram, internal clock divided by 2
TIMER_CK
CEN
CNT_CLK
CNT_REG
overflow
61
Update event (UPE)
Update interrupt flag (UPIF)
62 63 00 01 02 03 04
Figure 9-89. Counter timing diagram, internal clock divided by 4
TIMER_CK
CEN
CNT_CLK
CNT_REG
overflow
62
Update event (UPE)
Update interrupt flag (UPIF)
63 00 01
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262
Figure 9-90. Counter timing diagram, internal clock divided by N
TIMER_CK
CNT_CLK
CNT_REG
overflow
31
Update event (UPE)
Update interrupt flag (UPIF)
32 00
Figure 9-91. Counter timing diagram, update event when ARSE=0
TIMER_CK
CEN
CNT_CLK
CNT_REG
overflow
5E 5F 60 61 62 63 00 01 02 03 04 05 06 07
Update event (UPE)
Update interrupt flag (UPIF)
Auto-reload register 65 63
modify CAR Vaule
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263
Figure 9-92. Counter timing diagram, update event when ARSE=1
TIMER_CK
CEN
CNT_CLK
CNT_REG
overflow
60 61 62 63 64 65 00 01 02 03 04 05 06 07
Update event (UPE)
Update interrupt flag (UPIF)
Auto-reload register 65 63
modify CAR Vaule
Auto-reload shadow register 65 63
Clock selection
Basic timer has the unique clock source which is controlled by RCU. Counter and prescaler
counter are clocked by this internal clock, except UPG is asserted. UPG’s assert will initial
counter and prescaler counter.
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264
Figure 9-93. Control circuit in normal mode, internal clock divided by 1
TIMER_CK
CEN
CNT_CLK
CNT_REG
Reload Pulse
17 18 19 20 21 22
UPG
23 00 01 02 03 04 05 06
Capture/compare channels
The TIMER13 has one independent channel which can be used as capture inputs or compare
match outputs. Each channel is built around a channel capture/compare value register
including an input stage, channel controller and an output stage.
Input capture stage
The input stage consists of a digital filter, a channel polarity selection, edge detection and a
channel prescaler. The channel input signal (CIx) can be chosen to come from the
TIMERx_CH0 signal. The channel input signal (CIx) is sampled by a digital filter to generate
a filtered input signal CIxF. Then the channel polarity and the edge detection block can
generate a CIxFEx signal for the input capture function. The effective input event number can
be set by the channel input prescaler (CHxCAPPSC).
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Figure 9-94. Capture/compare channel (example: input stage)
filter
downcounter
CI0
CH0CAPFLT
[3:0]
CHCTL0
fDTS
Edge Detector CI0F_Falling
CI0F_Rising 0
1
CH0P/
CH0NP
CHCTL2
01
CH0MS[ 1:0 ]
CHCTL0
10
11
CI0FE0
CI1FE0
ITS
divider
/1, /2, /4, /8
CH0CAPPS
C[1:0]
CHCTL0
CH0EN
CHCTL2
IC0
Channel controller
The GPTM has one independent channels which can be used as capture inputs or compare
match outputs.
When used in the input capture mode, the counter value is captured into the TIMERx_CHxCV
shadow register first and then transferred into the TIMERx_CHxCV preload register when the
capture event occurs.
When used in the compare match output mode, the contents of the TIMERx_CHxCV preload
register is copied into the associated shadow register; the counter value is then compared
with the register value.
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Figure 9-95. Capture/compare channel 0 main circuit
APB BUS
MCU-peripheral interface
Capture/compare preload register
Capture/compare shadow
register
Counter
CH0VAL
CH0MS[0]
CH0MS[1]
CH0CAPPSC
CH0EN
CH0G
TIMER_SWEVG
CH0VAL
CH0MS[0]
CH0MS[1]
CH0COMSEN
UPE
CNT>CH0VAL
CNT=CH0VAL
Output stage
The TIMER13 has one channel for compare match or PWM output function.
Figure 9-96. Output stage of capture/compare channel
Output mode controller
CNT>CH0VAL
CNT=CH0VAL
CH0COMCTL[
2:0]
CHCTL0
ETI
0
1
CH3P
CHCTL2
Output enable
circuit
CHx_O
CHxEN
CHCTL2
Input Capture Mode
When the channel is used as a capture input, the counter value is captured into the Channel
Capture/Compare Register (TIMERx_CHxCV) when an effective input signal transition occurs.
Once the capture event occurs, the CHxIF flag in the TIMERx_INTF register is set. If the
CHxIF bit is already set, i.e., the flag has not yet been cleared by software, and another
capture event on this channel occurs, the corresponding channel Over-Capture flag, named
CHxOF, will be set.Once the capture event occurs, an interrupt is generated depending on
the CHxIE bit. The fllowing step maybe used to implement input capture mode:
Select input signal by set CHxMS bits in the channel control register (TIMERx_CHCTLx).
Add input filter to input signal by set CHxCAPFLT bitst in the the channel control register
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(TIMERx_CHCTLx).
Select input capture edge (rising or falling) by set CHxP/CHxNP bit in the channel control
register 2 (TIMERx_CHCTL2).
If input signal need prescaler, set CHxCAPPSC bits in the the channel control register
(TIMERx_CHCTLx).
If need interrupt, set CHxIE bit in DMA and interrupt enable register
(TIMERx_DMAINTEN) to 1.
Enable the channel by set CHxEN bit in the channel control register 2 (TIMERx_CHCTL2)
to 1.
After configure this registers, the input capture event on this channel may occurs at the
corresponding edge. And the counter value is captured into the Channel Capture/Compare
Register (TIMERx_CHxCV). An interrupt generated if CHxIE bit set.
The input capture mode can be also used for pulse width measurement from signals on the
TIMERx_CHx pins (CIx). For example, PWM signal connect to CI0 input. Select channel 0
capture signal to CI0 by setting CH0MS to 01 in the channel control register
(TIMERx_CHCTL0) and set capture on rising edge. Select channel 1 capture signal to CI0 by
setting CH1MS to 10 in the channel control register (TIMERx_CHCTL0) and set capture on
falling edge. The counter set to restart mode and restart on channel 0 rising edge. Then the
TIMERx_CH0CV can measure the PWM period and the TIMERx_CH1CV can measure the
PWM duty.
Output Compare Mode/PWM Mode
When the channel is used as an output mode by setting the CHxMS in the the channel control
register (TIMERx_CHCTLx) to 00, the channel outputs waveform according to the
CHxCOMCTL bits in the the the channel control register (TIMERx_CHCTLx), and the
comparision between the counter and TIMERx_CHxCV registers. When the comparision
equals, the CHxIF flag in the Interrupt flag registers (TIMERx_INTF) set to 1. An interrupt is
generated depending on the CHxIE bit.
In output mode, the channel can outputs active level by set the CHxCOMCTL to 101, and
outputs inactive level by set the CHxCOMCTL bits to 100.
In ouput mode, the channel output set to active level when the comparision between the
counter and TIMERx_CHxCV registers match, by set the CHxCOMCTL to 001. The channel
output set to inactive level when the comparision between the counter and TIMERx_CHxCV
registers match, by set the CHxCOMCTL to 010.
In output compare toggle mode (by set the CHxCOMCTL to 011), the channel output toggles
when the comparision between the counter and TIMERx_CHxCV registers match.
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Figure 9-97. Output compare toggle mode, toggle on CH0_O
CNT_REG
O0CPRE=CH0_O
003A0039
CH0VAL
003B B200 B201
003A B201
Match detected on CH0VAL
Interrupt generated if enabled
Write B201h in the CH0VAL
register
In the output PWM mode (by setting the CHxCOMCTL bits to 110 (PWM mode 0) or to 111
(PWM mode 1)), the channel can outputs PWM waveform according to the TIMERx_CAR
registers and TIMERx_CHxCV registers.
Figure 9-98. Output compare PWM mode 0 on CH0_O, upcounting mode
CNT_REG
O0CPRE=CH0_O
003A0039
CH0VAL
003B 100 0
003A
Match detected on CH0VAL
Interrupt generated if enabled
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Figure 9-99. Output compare PWM mode 0 on CH0_O, center-aligned counting mode
CNT_REG
O0CPRE=CH0_O
003A0039
CH0VAL
003B 0100 00FF
003A
Match detected on CH0VAL
Interrupt generated if enabled
00FE 003B 003A 0039
Channel Output Reference Signal
When the TIMER13 is used in the compare match output mode, the OxCPRE signal (Channel
x Output Reference signal) is defined by setting the CHxCOMCTL bits. The OxCPRE signal
has several types of output function. These include, keeping the original level by setting the
CHxCOMCTL field to 0x00, set to 1 by setting the CHxCOMCTL field to 0x01, set to 0 by
setting the CHxCOMCTL field to 0x02 or signal toggle by setting the CHxCOMCTL field to
0x03 when the counter value matches the content of the TIMERx_CHxCV register.
The PWM mode 0 and PWM mode 1 outputs are also another kind of OxCPRE output which
is setup by setting the CHxCOMCTL field to 0x06/0x07. In these modes, the OxCPRE signal
level is changed according to the counting direction and the relationship between the counter
value and the TIMERx_CHxCV content. With regard to a more detailed description refer to
the relative bit definition.
Another special function of the OxCPRE signal is a forced output which can be achieved by
setting the CHxCOMCTL field to 0x04/0x05. Here the output can be forced to an
inactive/active level irrespective of the comparison condition between the counter and the
TIMERx_CHxCV values.
The OxCPRE signal can be forced to 0 when the ETIF signal is derived from the external
TIMERx_ETI pin and when it is set to a high level by setting the CHxCOMCEN bit to 1 in the
TIMERx_CHCTL0 register. The OxCPRE signal will not return to its active level until the next
update event occurs.
Timer debug mode
When the Cortex™-M3 halted, and the DBG_TIMERx_STOP configuration bit in DBG module
set to 1, the TIMERx counter stops.
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9.4.4. TIMER13 registers
Control register 0 (TIMERx_CTL0)
Address offset: 0x00
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
CKDIV[1:0]
ARSE
Reserved
UPS
UPDIS
CEN
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
15:10
Reserved
Must be kept at reset value
9:8
CKDIV[1:0]
Clock division
The CKDIV bits can be configured by software to specify division ratio between the
timer clock (TIMER_CK) and the dead-time and sampling clock (DTS), which is used
by the dead-time generators and the digital filters.
00: fDTS=fTIMER_CK
01: fDTS= fTIMER_CK /2
10: fDTS= fTIMER_CK /4
11: Reserved
7
ARSE
Auto-reload shadow enable
0: The shadow register for TIMERx_CAR register is disabled
1: The shadow register for TIMERx_CAR register is enabled
6:3
Reserved
Must be kept at reset value
2
UPS
Update source
This bit is used to select the update event sources by software.
0: When enabled, any of the following events generate an update interrupt:
– The UPG bit is set
– The counter generates an overflow or underflow event
– The slave mode controller generates an update event.
1: When enabled, only counter overflow/underflow generates an update interrupt.
1
UPDIS
Update disable.
This bit is used to enable or disable the update event generation.
0: update event enable. The update event is generate and the buffered registers are
loaded with their preloaded values when one of the following events occurs:
– The UPG bit is set
– The counter generates an overflow or underflow event
– The slave mode controller generates an update event.
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1: update event disable. The buffered registers keep their value, while the counter
and the prescaler are reinitialized if the UPG bit is set or if the slave mode controller
generates a hardware reset event.
0
CEN
Counter enable
0: Counter disable
1: Counter enable
The CEN bit must be set by software when timer works in external clock, pause mode
and encoder mode. While in event mode, the hardware can set the CEN bit
automatically.
Interrupt enable register (TIMERx_DMAINTEN)
Address offset: 0x0C
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
CH0IE
UPIE
rw
rw
Bits
Fields
Descriptions
15:2
Reserved
Must be kept at reset value.
1
CH0IE
Channel 0 interrupt enable
0: Channel 0 interrupt disabled
1: Channel 0 interrupt enabled
0
UPIE
Update interrupt enable
0: Update interrupt disabled
1: Update interrupt enabled
Interrupt flag register (TIMERx_INTF)
Address offset: 0x10
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
CH0OF
Reserved
CH0IF
UPIF
rc_w0
rc_w0
rc_w0
Bits
Fields
Descriptions
15:10
Reserved
Must be kept at reset value.
9
CH0OF
Channel 0 Capture overflow flag
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When channel 0 is configured in input mode, this flag is set by hardware when a
capture event occurs while CH0IF flag has already been set. This flag is cleared by
software.
0: No Capture overflow interrupt occurred
1: Capture overflow interrupt occurred
8:2
Reserved
Must be kept at reset value.
1
CH0IF
Channel 0 interrupt flag
This flag is set by hardware and cleared by software. When channel 0 is in input
mode, this flag is set when a capture event occurs. When channel 0 is in output
mode, this flag is set when a compare event occurs.
0: No Channel 0 interrupt occurred
1: Channel 0 interrupt occurred
0
UPIF
Update interrupt flag
This bit is set by hardware on an update event and cleared by software.
0: No update interrupt occurred
1: Update interrupt occurred
Software event generation register (TIMERx_SWEVG)
Address offset: 0x14
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
CH0G
UPG
w
w
Bits
Fields
Descriptions
15:2
Reserved
Must be kept at reset value.
1
CH0G
Channel 0’s capture or compare event generation
This bit is set by software in order to generate a capture or compare event in
channel 0, it is automatically cleared by hardware. When this bit is set, the CH0IF
flag is set, the corresponding interrupt or DMA request is sent if enabled. In
addition, if channel 0 is configured in input mode, the current value of the counter is
captured in TIMER0_CH0CV register, and the CH0OF flag is set if the CH0IF flag
was already high.
0: No generate a channel 0 capture or compare event
1: Generate a channel 0 capture or compare event
0
UPG
This bit can be set by software, and cleared by hardware automatically. When this
bit is set, the counter is cleared if the center-aligned or upcounting mode is
selected, else (downcounting) it takes the auto-reload value. The prescaler counter
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is cleared at the same time.
0: No generate an update event
1: Generate an update event
Channel control register 0 (TIMERx_CHCTL0)
Address offset: 0x18
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
CH0COMCEN
CH0COMCTL[2:0]
CH0COMSEN
CH0COMFEN
CH0MS[1:0]
CH0CAPFLT[3:0]
CH0CAPPSC[1:0]
rw
rw
rw
rw
rw
rw
rw
rw
Output compare mode:
Bits
Fields
Descriptions
15:8
Reserved
Must be kept at reset value.
7
CH0COMCEN
Channel 0 output compare clear enable.
When this bit is set, the O0CPRE signal is cleared when High level is detected on
ETIF input.
0: Channel 0 output compare clear disable
1: Channel 0 output compare clear enable
6:4
CH0COMCTL[2:0]
Channel 0 compare output control
This bit-field specifies the behavior of the output reference signal O0CPRE which
drives CH0_O and CH0_ON. O0CPRE is active high, while CH0_O and CH0_ON
active level depends on CH0P and CH0NP bits.
000: Frozen.The O0CPRE signal keep stable, independent of the comparison
between the output compare register TIMERx_CH0CV and the counter.
001: Set high on match.O0CPRE signal is forced high when the counter matches
the output compare register TIMERx_CH0CV.
010: Set low on match. O0CPRE signal is forced low when the counter matches
the c output compare register TIMERx_CH0CV.
011: Toggle on match. O0CPRE toggles when the counter matches the c output
compare register TIMERx_CH0CV.
100: Force low. O0CPRE is forced low level.
101: Force high. O0CPRE is forced high level.
110: PWM mode 0. When counting up, O0CPRE is high as long as the counter is
smaller than TIMERx_CH0CV else low. When counting down, O0CPRE is low as
long as the counter is larger than TIMERx_CH0CV else high.
111: PWM mode 1. When counting up, O0CPRE is low as long as the counter is
smaller than TIMERx_CH0CV else high. When counting down, O0CPRE is high
as long as the counter is larger than TIMERx_CH0CV else low.
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When configured in PWM mode, the O0CPRE level changes only when the output
compare mode switches from “frozen” mode to “PWM” mode or when the result of
the comparison changes.
3
CH0COMSEN
Channel 0 output compare shadow enable
When this bit is set, the shadow register of TIMERx_CH0CV register, which
updates at each update event will be enabled.
0: Channel 0 output compare shadow disable
1: Channel 0 output compare shadow enable
The PWM mode can be used without validating the shadow register only in one
pulse mode (SPM bit set in TIMERx_CTL0 register is set).
2
CH0COMFEN
Channel 0 output compare fast enable
When this bit is set, the effect of an event on the trigger in input on the
Capture/Compare output will be accelerated if the channel is configured in PWM0
or PWM1 mode. The output channel will treat an active edge on the trigger input
as a compare match, and CH0_O is set to the compare level independently from
the result of the comparison.
0: Channel 0 output compare fast disable. The minimum delay from an edge on
the trigger input to activate CH0_O output is 5 clock cycles.
1: Channel 0 output compare fast enable. The minimum delay from an edge on
the trigger input to activate CH0_O output is 3 clock cycles.
1:0
CH0MS[1:0]
Channel 0 mode selection
This bit-field specifies the direction of the channel and the input signal selection.
This bit-field is writable only when the channel is OFF (CH0EN bit in
TIMERx_CHCTL2 register is reset).
00: Channel 0 is configured as output
01: Channel 0 is configured as input, IC0 is connected to CI0FE0
10: Channel 0 is configured as input, IC0 is connected to CI1FE0
11: Channel 0 is configured as input, IC0 is connected to ITS. This mode is
working only if an internal trigger input is selected through TRGS bits in
TIMERx_SMCFG register.
Input capture mode:
Bits
Fields
Descriptions
15:8
Reserved
Must be kept at reset value
7:4
CH0CAPFLT[3:0]
Channel 0 input capture filter control
An event counter is used in the digital filter, in which a transition on the output
occurs after N input events. This bit-field specifies the frequency used to sample
CI0 input signal and the length of the digital filter applied to CI0.
0000: Filter disable, fSAMP=fDTS, N=1
0001: fSAMP=fTIMER_CK, N=2
0010: fSAMP= fTIMER_CK, N=4
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0011: fSAMP= fTIMER_CK, N=8
0100: fSAMP=fDTS/2, N=6
0101: fSAMP=fDTS/2, N=8
0110: fSAMP=fDTS/4, N=6
0111: fSAMP=fDTS/4, N=8
1000: fSAMP=fDTS/8, N=6
1001: fSAMP=fDTS/8, N=8
1010: fSAMP=fDTS/16, N=5
1011: fSAMP=fDTS/16, N=6
1100: fSAMP=fDTS/16, N=8
1101: fSAMP=fDTS/32, N=5
1110: fSAMP=fDTS/32, N=6
1111: fSAMP=fDTS/32, N=8
3:2
CH0CAPPSC[1:0]
Channel 0 input capture prescaler
This bit-field specifies the ratio of the prescaler on channel 0 input.The prescaler is
reset when CH0EN bit in TIMERx_CHCTL2 register is reset.
00: Prescaler disable, capture is done on each channel input edge
01: Capture is done every 2 channel input edges
10: Capture is done every 4channel input edges
11: Capture is done every 8 channel input edges
1:0
CH0MS[1:0]
Channel 0 mode selection
This bit-field specifies the direction of the channel and the input signal selection.
This bit-field is writable only when the channel is OFF (CH0EN bit in
TIMERx_CHCTL2 register is reset).
00: Channel 0 is configured as output
01: Channel 0 is configured as input, IC0 is connected to CI0FE0
10: Channel 0 is configured as input, IC0 is connected to CI1FE0
11: Channel 0 is configured as input, IC0 is connected to ITS. This mode is
working only if an internal trigger input is selected through TRGS bits in
TIMERx_SMCFG register.
Channel control register 2 (TIMERx_CHCTL2)
Address offset: 0x20
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
CH0NP
Res.
CH0P
CH0EN
rw
rw
rw
Bits
Fields
Descriptions
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276
15:4
Reserved
Must be kept at reset value
3
CH0NP
Channel 0 complementary output polarity
When channel 0 is configured in output mode, this bit specifies the complementary
output signal polarity.
0: Channel 0 active high
1: Channel 0 active low
2
Reserved
Must be kept at reset value
1
CH0P
Channel 0 polarity
When channel 0 is configured in input mode, this bit specifies the CI0 signal
polarity. When channel 0 is configured in output mode, this bit specifies the output
signal polarity.
0: Channel 0 active high
1: Channel 0 active low
This bit cannot be modified when PROT[1:0] bit-filed in TIMERx_CCHP register is
11 or 10.
0
CH0EN
Channel 0 enable
When channel 0 is configured in input mode, setting this bit enables CH0_O signal
in active state. When channel 0 is configured in output mode, setting this bit enables
the capture event in channel 0.
0: Channel 0 disabled
1: Channel 0 enabled
Counter register (TIMERx_CNT)
Address offset: 0x24
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
CNT[15:0]
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
15:0
CNT[15:0]
This bit-filed indicates the current counter value. Writing to this bit-filed can change
the value of the counter.
Prescaler register (TIMERx_PSC)
Address offset: 0x28
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
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15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
PSC[15:0]
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
15:0
PSC[15:0]
Prescaler value of the counter clock
The PSC clock is divided by (PSC+1) to generate the counter clock. The
value of this bit-filed will be loaded to the corresponding shadow register at
every update event.
Counter auto reload register (TIMERx_CAR)
Address offset: 0x2C
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
CAR[15:0]
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
15:0
CAR[15:0]
Counter auto reload value
This bit-filed specifies the auto reload value of the counter.
Channel 0 capture/compare value register (TIMERx_CH0CV)
Address offset: 0x34
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
CH0VAL[15:0]
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
15:0
CH0VAL[15:0]
Capture or compare value of channel 0
When channel 0 is configured in input mode, this bit-filed indicates the counter
value corresponding to the last capture event. And this bit-filed is read-only.
When channel 0 is configured in output mode, this bit-filed contains value to be
compared to the counter. When the corresponding shadow register is enabled, the
shadow register updates every update event.
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Channel input remap register(TIMERx_IRMP)
Address offset: 0x50
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
CI0_RMP[1:0]
rw
Bits
Fields
Descriptions
15:2
Reserved
Must be kept at reset value
1:0
CI0_RMP[1:0]
Channel 0 input remap
00: Channel 0 input is connected to GPIO(TIMER13_CH0)
01: Channel 0 input is connected to the RTCCLK
10: Channel 0 input is connected to HXTAL/32 clock
11: Channel 0 input is connected to CKOUTSEL(in GD32F130xx and GD32F150xx
devices )/CKOUT0SEL(in GD32F170xx and GD32F190xx devices), which is
controlled by RCU_CFG0.
Configuration register (TIMERx_CFG) of GD32F170xx and GD32F190xx
devices
Address offset: 0xFC
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
CCSEL
Reserved
rw
Bits
Fields
Descriptions
15:2
Reserved
Must be kept at reset value
1
CCSEL
Write Capture/Compare register selection
This bit-field set and reset by software.
1: If write the Capture/Compare register, the write value is same as the
Capture/Compare value, the write access ignored
0: No effect
0
Reserved
Must be kept at reset value
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9.5. General timer (TIMER14)
9.5.1. Introduction
The general timer, known as TIMER14, may be used for a variety of purposes. It consists of
one 16-bit up-counter; two 16-bit capture/compare registers (TIMERx_CHxCV), one 16-bit
counter auto reload register (TIMERx_CAR) and several control registers. They can be used
for a variety of purposes including general timer, input signal pulse width measurement or
output waveform generation such as single pulse generation or PWM output.
The general (TIMER14) timers are completely independent. They do not share any resources
but can be synchronized together.
9.5.2. Main features
16-bit up auto-reload counter.
16-bit programmable prescaler that allows division of the counter clock frequency by any
factor between 1 and 65536.
Up to 2 independent channels support functions including input capture, compare match
output, generation of PWM waveform (edge and center-aligned Mode), and single pulse
mode output.
Counter repetition to update the timer registers only after a given number of cycles of the
counter.
Break input to trigger the timer’s output signals to a known state.
Interrupt/DMA generation by update, trigger event, input capture event, output compare
match event or break input
Programmable dead-time for output match.
Synchronization circuit to control TIMER14 with external signals or to interconnect
several timers together.
TIMER14 Master/Slave mode controller
9.5.3. Function description
Figure below provides details on the internal configuration of the advanced timer.
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Figure 9-100. Gereral timer block diagram (TIMER14)
Trigger
Controller
Mode Slave
Controller
ITI0
ITI1
ITI2
ITI3
TMER14_CK
CI0FE0
CI1FE0
CI0F_ED
TRGO
CH0
CH1
BRKIN Polarity Selection
Input Filter Edge Detector Prescaler
Capture Register
Compare Register
Prescaler
Counter
AutoReload
Register
Repetition
counter
Repeat
Register
DTG Output
Control
CH0
CH0_N
CH1
Reset, Enable, Up/Down, Count
Prescaler counter
The prescaler can divide the timer clock (TIMER_CK) to the counter clock (CNT_CLK) by any
factor between 1 and 65536. It is controlled through prescaler register (TIMERx_PSC) which
can be changed on the fly but be taken into account at the next update event.
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Figure 9-101. Counter timing diagram with prescaler division change from 1 to 2
TIMER_CK
CEN
CNT_CLK
CNT_REG
Reload Pulse
Prescaler CNT
Prescaler BUF
Prescaler CR
F7 F8 F9 FA FB FC 01 02 03 04
01
0 1
0 0 1 0 1 0 1 0 1
modify scaler Vaule
Figure 9-102. Counter timing diagram with prescaler division change from 1 to 4
TIMER_CK
CEN
CNT_CLK
CNT_REG
Reload Pulse
Prescaler CNT
Prescaler BUF
Prescaler CR
F7 F8 F9 FA FB FC 00 01
03
0 3
0 0 1 2 3 0 1 2 3
modify PSC Vaule
Upcounting mode
In this mode the counter counts continuously from 0 to the counter-reload value, which is
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defined in the TIMERx_CAR register, in a count-up direction. Once the counter reaches the
counter reload value, the counter restarts to count once again from 0. If the repetition counter
is set, the update eventis generated after the number of overflow. Else the update event is
generated at each counter overflow.
When the update event is set by the UPG bit in the TIMERx_SWEVG register, the counter
value will be initialized to 0 and generates an update event.
If set the UPDIS bit in TIMERx_CTL0 register, the update event is disabled.
When an update event occurs, all the registers (repeatition counter, autoreload register,
prescaler register) are updated.
The following figures show some examples of the counter behavior for different clock
frequencies when TIMERx_CAR=0x63.
Figure 9-103. Counter timing diagram, internal clock divided by 1
TIMER_CK
CEN
CNT_CLK
CNT_REG
overflow
5E 5F 60 61 62 63 00 01 02 03 04 05 06 07
Update event (UPE)
Update interrupt flag (UPIF)
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Figure 9-104. Counter timing diagram, internal clock divided by 2
TIMER_CK
CEN
CNT_CLK
CNT_REG
overflow
61
Update event (UPE)
Update interrupt flag (UPIF)
62 63 00 01 02 03 04
Figure 9-105. Counter timing diagram, internal clock divided by 4
TIMER_CK
CEN
CNT_CLK
CNT_REG
overflow
62
Update event (UPE)
Update interrupt flag (UPIF)
63 00 01
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Figure 9-106. Counter timing diagram, internal clock divided by N
TIMER_CK
CNT_CLK
CNT_REG
overflow
31
Update event (UPE)
Update interrupt flag (UPIF)
32 00
Figure 9-107. Counter timing diagram, update event when ARSE=0
TIMER_CK
CEN
CNT_CLK
CNT_REG
overflow
5E 5F 60 61 62 63 00 01 02 03 04 05 06 07
Update event (UPE)
Update interrupt flag (UPIF)
Auto-reload register 65 63
modify CAR Vaule
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Figure 9-108. Counter timing diagram, update event when ARSE=1
TIMER_CK
CEN
CNT_CLK
CNT_REG
overflow
60 61 62 63 64 65 00 01 02 03 04 05 06 07
Update event (UPE)
Update interrupt flag (UPIF)
Auto-reload register 65 63
modify CAR Vaule
Auto-reload shadow register 65 63
Counter Repetition
Counter Repetition is used to generator update event or updates the timer registers only after
a given number (N+1) of cycles of the counter, where N is CREP in TIMERx_CREP register.
The repetition counter is decremented at each counter overflow in up-counting mode, at each
counter underflow in down-counting mode or at each counter overflow and at each counter
underflow in center-aligned mode.
Setting the UPG bit in the TIMERx_SWEVG register will reload the content of CREP in
TIMERx_CREP register and generator an update event.
Figure 9-109. Update rate examples depending on mode and TIMERx_CREP
TIMER14 has only upcounting edge-aligned mode.
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Center-aligned mode Upcounting
Edge-aligned mode
Downcounting
Edge-aligned mode
CREP = 0
CREP = 1
Clock selection
The following describes the Timer Module clock controller which determines the clock source
of the internal prescaler counter.
Internal timer clock TIMER_CK
The default internal clock source is the APB2 clock CK_APB2 used to drive the counter
prescaler when the slave mode is disabled. If the slave mode controller is enabled by setting
SMC field in the TIMERx_SMCFG register to an available value including 0x1, 0x2, 0x3 and
0x7, the prescaler is clocked by other clock sources selected by the TRGS field in the
TIMERx_SMCFG register and described as follows. When the slave mode selection bits SMC
are set to 0x4, 0x5 or 0x6, the internal clock TIMER_CK is the counter prescaler driving clock
source.
Figure 9-110. Control circuit in normal mode, internal clock divided by 1
TIMER_CK
CEN
CNT_CLK
CNT_REG
Reload Pulse
17 18 19 20 21 22
UPG
23 00 01 02 03 04 05 06
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Internal trigger inputs (ITI)
The counter prescaler can count during each rising or falling edge of the ITI signal. This mode
can be selected by setting the SMC field to 0x6 in the TIMERx_SMCFG register;here the
counter will act as an event counter. The input event, known as ITI here, can be selected by
setting the TRGS field. When the ITI signal is selected as the clock source, the internal edge
detection circuitry will generate a clock pulse during each ITI signal rising or falling edge to
drive the counter prescaler.
Channel input pin (CI)
The counter prescaler can be driven to count during each rising or falling edge on the external
pin TIMERx_CIx. This mode can be selected by setting SMC field to 0x7 and the TRGS field
to 0x4, 0x5 or 0x6. Note that the CIx is derived from the TIMERx_CHx sampled by a digital
filter.
Capture/compare channels
The TIMER14 has two independent channels which can be used as capture inputs or
compare match outputs. Each channel is built around a channel capture/compare value
register including an input stage, channel controller and an output stage.
Input capture stage
The input stage consists of a digital filter, a channel polarity selection, edge detection and a
channel prescaler. The channel input signal (CIx) is sampled by a digital filter to generate a
filtered input signal CIxF. Then the channel polarity and the edge detection block can generate
a CIxFEx signal for the input capture function. The effective input event number can be set
by the channel input prescaler (CHxCAPPSC).
Figure 9-111. Capture/compare channel (example: channel 0 input stage)
filter
downcounter
CI0
CH0CAPFLT
[3:0]
CHCTL0
fDTS
Edge Detector CI0F_Falling
CI0F_Rising 0
1
CH0P/
CH0NP
CHCTL2
01
CH0MS[ 1:0 ]
CHCTL0
10
11
CI0FE0
CI1FE0
ITS
divider
/1, /2, /4, /8
CH0CAPPS
C[1:0]
CHCTL0
CH0EN
CHCTL2
IC0
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Channel controller
The GPTM has two independent channels which can be used as capture inputs or compare
match outputs.
When used in the input capture mode, the counter value is captured into the TIMERx_CHxCV
shadow register first and then transferred into the TIMERx_CHxCV preload register when the
capture event occurs.
When used in the compare match output mode, the contents of the TIMERx_CHxCV preload
register is copied into the associated shadow register; the counter value is then compared
with the register value.
Figure 9-112. Capture/compare channel 0 main circuit
APB BUS
MCU-peripheral interface
Capture/compare preload register
Capture/compare shadow
register
Counter
CH0VAL
CH0MS[0]
CH0MS[1]
CH0CAPPSC
CH0EN
CH0G
TIMER_SWEVG
CH0VAL
CH0MS[0]
CH0MS[1]
CH0COMSEN
UPE
CNT>CH0VAL
CNT=CH0VAL
Output stage
The TIMER14 has two channels for compare match, single pulse or PWM output function.
Figure 9-113. Output stage of capture/compare channel (channel 0)
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Output mode controller
CNT>CH0VAL
CNT=CH0VAL
CH0COMCTL
[2:0]
CHCTL0
ETI
0
1
CH0NP
CHCTL2
11
CH0MS[ 1:0 ]
CHCTL0
10
x0
Dead-time
generator
DTCFG
[7:0]
CCHP
x0
CH0MS[ 1:0 ]
CHCTL0
10
11
0
1
CH0P
CHCTL2
Output
enable
circuit
CHx_O
Output
enable
circuit
CHx_ON
CH0NEN
CHCTL2
POEN
CCHP ROS IOS
CH0EN
CHCTL2
CH0COM
CEN
Figure 9-114. Output stage of capture/compare channel (channel 1)
Output mode controller
CNT>CH1VAL
CNT=CH1VAL
CH3COMCTL[
2:0]
CHCTL0
ETI
0
1
CH3P
CHCTL2
Output enable
circuit
CHx_O
CHxEN
CHCTL2
POE
CCHP ROS
CH3COM
CEN
Input Capture Mode
When the channel is used as a capture input, the counter value is captured into the Channel
Capture/Compare Register (TIMERx_CHxCV) when an effective input signal transition occurs.
Once the capture event occurs, the CHxIF flag in the TIMERx_INTF register is set. If the
CHxIF bit is already set, i.e., the flag has not yet been cleared by software, and another
capture event on this channel occurs, the corresponding channel Over-Capture flag, named
CHxOF, will be set.Once the capture event occurs, a DMA request is generated depending
on the CHxDEN bit and an interrupt is generated depending on the CHxIE bit. The fllowing
step maybe used to implement input capture mode:
Select input signal by set CHxMS bits in the channel control register (TIMERx_CHCTLx).
Add input filter to input signal by set CHxCAPFLT bitst in the the channel control register
(TIMERx_CHCTLx).
Select input capture edge (rising or falling) by set CHxP/CHxNP bit in the channel control
register 2 (TIMERx_CHCTL2).
If input signal need prescaler, set CHxCAPPSC bits in the the channel control register
(TIMERx_CHCTLx).
If need interrupt, set CHxIE bit in DMA and interrupt enable register
(TIMERx_DMAINTEN) to 1.
If need DMA request, set CHxDEN bit in DMA and interrupt enable register
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(TIMERx_DMAINTEN) to 1.
Enable the channel by set CHxEN bit in the channel control register 2 (TIMERx_CHCTL2)
to 1.
After configure this registers, the input capture event on this channel may occurs at the
corresponding edge. And the counter value is captured into the Channel Capture/Compare
Register (TIMERx_CHxCV). An interrupt generated if CHxIE bit set. A DMA request
generated if CHxDEN set.
The input capture mode can be also used for pulse width measurement from signals on the
TIMERx_CHx pins (CIx). For example, PWM signal connect to CI0 input. Select channel 0
capture signal to CI0 by setting CH0MS to 01 in the channel control register
(TIMERx_CHCTL0) and set capture on rising edge. Select channel 1 capture signal to CI0 by
setting CH1MS to 10 in the channel control register (TIMERx_CHCTL0) and set capture on
falling edge. The counter set to restart mode and restart on channel 0 rising edge. Then the
TIMERx_CH0CV can measure the PWM period and the TIMERx_CH1CV can measure the
PWM duty.
Output Compare Mode/PWM Mode
When the channel is used as an output mode by setting the CHxMS in the the channel control
register (TIMERx_CHCTLx) to 00, the channel outputs waveform according to the
CHxCOMCTL bits in the the the channel control register (TIMERx_CHCTLx), and the
comparision between the counter and TIMERx_CHxCV registers. When the comparision
equals, the CHxIF flag in the Interrupt flag registers (TIMERx_INTF) set to 1. A DMA request
is generated depending on the CHxDEN bit and an interrupt is generated depending on the
CHxIE bit.
In output mode, the channel can outputs active level by set the CHxCOMCTL to 101, and
outputs inactive level by set the CHxCOMCTL bits to 100.
In ouput mode, the channel output set to active level when the comparision between the
counter and TIMERx_CHxCV registers match, by set the CHxCOMCTL to 001. The channel
output set to inactive level when the comparision between the counter and TIMERx_CHxCV
registers match, by set the CHxCOMCTL to 010.
In output compare toggle mode (by set the CHxCOMCTL to 011), the channel output toggles
when the comparision between the counter and TIMERx_CHxCV registers match.
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Figure 9-115. Output compare toggle mode, toggle onCH0_O
CNT_REG
O0CPRE=CH0_O
003A0039
CH0VAL
003B B200 B201
003A B201
Match detected on CH0VAL
Interrupt generated if enabled
Write B201h in the CH0VAL
register
In the output PWM mode (by setting the CHxCOMCTL bits to 110 (PWM mode 0) or to 111
(PWM mode 1)), the channel can outputs PWM waveform according to the TIMERx_CAR
registers and TIMERx_CHxCV registers.
Figure 9-116. Output compare PWM mode 0 on CH0_O, upcounting mode
CNT_REG
O0CPRE=CH0_O
003A0039
CH0VAL
003B 100 0
003A
Match detected on CH0VAL
Interrupt generated if enabled
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Figure 9-117. Output compare PWM mode 0 on CH0_O, center-aligned counting mode
CNT_REG
OxCPRE=CHx_O
003A0039
CH0VAL
003B 0100 00FF
003A
Match detected on CH0VAL
Interrupt generated if enabled
00FE 003B 003A 0039
Channel Output Reference Signal
When the TIMER14 is used in the compare match output mode, the OxCPRE signal (Channel
x Output Reference signal) is defined by setting the CHxCOMCTL bits. The OxCPRE signal
has several types of output function. These include, keeping the original level by setting the
CHxCOMCTL field to 0x00, set to 1 by setting the CHxCOMCTL field to 0x01, set to 0 by
setting the CHxCOMCTL field to 0x02 or signal toggle by setting the CHxCOMCTL field to
0x03 when the counter value matches the content of the TIMERx_CHxCV register.
The PWM mode 0 and PWM mode 1 outputs are also another kind of OxCPRE output which
is setup by setting the CHxCOMCTL field to 0x06/0x07. In these modes, the OxCPRE signal
level is changed according to the counting direction and the relationship between the counter
value and the TIMERx_CHxCV content. With regard to a more detailed description refer to
the relative bit definition.
Another special function of the OxCPRE signal is a forced output which can be achieved by
setting the CHxCOMCTL field to 0x04/0x05. Here the output can be forced to an
inactive/active level irrespective of the comparison condition between the counter and the
TIMERx_CHxCV values.
The OxCPRE signal can be forced to 0 when the ETIF signal is derived from the external
TIMERx_ETI pin and when it is set to a high level by setting the CHxCOMCEN bit to 1 in the
TIMERx_CHCTL0 register. The OxCPRE signal will not return to its active level until the next
update event occurs.
Outputs Complementary and Dead-time
The TIMER14 can output two complementary signals. The complementary signals CHx_O
and CHx_ON are activated by a combination of several control bits: the CHxEN and CHxNEN
bits in the TIMERx_CHCTL2 register and the POEN, ISOx, ISOxN, IOS and ROS bits in the
TIMERx_CCHP and TIMERx_CTL1 registers.The outputs polarity are determined by CHxP
and CHxNP bits in the TIMERx_CHCTL2 register
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If CHxEN, CHxNEN and POEN bits are 1, dead-time should insertion. The rising edge of
CHx_O output is delayed relative to the rising edge of OxCPRE and the rising edge of
CHx_ON output is delayed relative to the falling edge of OxCPRE.The delay value is a 8-bit
dead-time counter determined by DTCFG field in TIMERx_CCHP register.If the delay value
is greater than the width of the active output (CHx_O or CHx_ON) then the corresponding
pulse is not generated.
Figure 9-118. Complementary output with dead-time insertion.
OxCPRE
CHx_O
CHx_ON
Dead_time
Dead_time
Figure 9-119. Dead-time waveforms with delay greater than the negative pulse
OxCPRE
CHx_O
CHx_ON
Dead_time
Figure 9-120. Dead-time waveforms with delay greater than the positive pulse
OxCPRE
CHx_ON
CHx_O
Dead_time
Break function
In this function, the output CHx_O and CHx_ON are controlled by the POEN, IOS and ROS
bits in the TIMERx_CCHP register, ISOx and ISOxN bits in the TIMERx_CTL1 register and
cannot be set both to active level when break occurs. The break sources are input break pin
or HXTAL stack event by Clock Monitor (CKM) in RCU. The break function enabled by setting
the BRKEN bit in the TIMERx_CCHP register. The break input polarity is setting by the BRKP
bit in TIMERx_CCHP.
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When a break occurs, the POEN bit is cleared asynchronously, the output CHx_O and
CHx_ON are driven with the level programmed in the ISOx bit in the TIMERx_CTL1 register
as soon as POEN is 0. If IOS is 0 then the timer releases the enable output else the enable
output remains high. The complementary outputs are first put in reset state, and then the
dead-time generator is reactivated in order to drive the outputs with the level programmed in
the ISOx and ISOxN bits after a dead-time.
When a break occurs, the BRKIF bit in the TIMERx_INTF register is set.
Figure 9-121. Output behavior in response to a break（The break input is acting on high
level）
OxCPRE
CHx_O
CHx_O
CHx_O
CHx_O
CHx_O
CHx_ON
CHx_O
CHx_ON
CHx_O
CHx_ON
CHx_O
CHx_ON
CHx_O
CHx_ON
Break_In
CHx_ON not implemented CHxP=0,ISOx=1
CHx_ON not implemented CHxP=0,ISOx=0
CHx_ON not implemented CHxP=1,ISOx=1
CHxEN=1, CHxP=0,ISOx=0,CHxNEN=1,CHxNP=0,ISOxN=1
CHxEN=1, CHxP=0,ISOx=1,CHxNEN=1,CHxNP=1,ISOxN=1
CHxEN=1, CHxP=0,ISOx=0,CHxNEN=0,CHxNP=0,ISOxN=1
CHxEN=1, CHxP=0,ISOx=1,CHxNEN=0,CHxNP=0,ISOxN=0
CHxEN=1, CHxP=0,CHxNEN=0,CHxNP=0,ISOx=0,ISOxN=0 or ISOx=0,ISOxN=1
delay
delaydelaydelay
delay delay
CHx_ON not implemented CHxP=0,ISOx=1
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Single Pulse Mode
Once the timer is set to operate in the single pulse mode, it is not necessary to set the timer
enable bit CEN in the TIMERx_CTL0 register to 1 to enable the counter. The trigger to
generate a pulse can be sourced from the trigger signals edge or by setting the CEN bit to 1
using software. Setting the CEN bit to 1 or a trigger from the trigger signals edge can generate
a pulse and then keep the CEN bit at a high state until the update event occurs or the CEN
bit is written to 0 by software. If the CEN bit is cleared to 0 using software, the counter will be
stopped and its value held. If the CEN bit is automatically cleared to 0 by a hardware update
event, the counter will be reinitialized.
In the Single Pulse mode, the trigger active edge which sets the CEN bit to 1 will enable the
counter. However, there exist several clock delays to perform the comparison result between
the counter value and the TIMERx_CHxCV value. In order to reduce the delay to a minimum
value, the user can set the CHxOFE bit in each TIMERx_CHCTL0 register. After a trigger
rising edge occurs in the single pulse mode, the OxCPRE signal will immediately be forced
to the state which the OxCPRE signal will change to, as the compare match event occurs
without taking the comparison result into account. The CHxOFE bit is available only when the
output channel is configured to operate in the PWM0 or PWM1 output mode and the trigger
source is derived from the trigger signal.
Figure 9-122. Single pulse mode
O0CPRE
CH0_O
CI1
CH0VAL
CARL
T
TIMER_CNT
Slave Controller
The TIMER14 can be synchronized with an external trigger in several modes including the
Restart mode, the Pause mode and the event mode which is selected by the SMC field in the
TIMERx_SMCFG register. The trigger input of these modes can be selected by the TRGS
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field in the TIMERx_SMCFG register, below to CI0 signal as an example.The operation
modes in the Slave Controller are described in the accompanying sections.
Restart mode
The counter and its prescaler can be reinitialized in response to a rising edge of the CI0 signal.
When a CI0 rising edge occurs, the update event software generation bit named UPG will
automatically be asserted by hardware and the trigger event flag will also be set. Then the
counter and prescaler will be reinitialized. Although the UPG bit is set to 1 by hardware, the
update event does not really occur. It depends upon whether the update event disable control
bit UPDIS is set to 1 or not. If UPDIS is set to 1 to disable the update event to occur, there
will no update event will be generated, however the counter and prescaler are still reinitialized
when the CI0 rising edge occurs. If the UPDIS bit in the TIMERx_CTL0 register is cleared to
enable the update event to occur, an update event will be generated together with the CI0
rising edge, then all the preloaded registers will be updated.
Figure 9-123. Control circuit in restart mode
CNT_CLK
CNT_REG 60 61 62 63 00 01 02 03 04 00 01 02 03 04
UPG
TRGIF
CI0
Pause mode
In the Pause Mode, the selected CI0 input signal level is used to control the counter start/stop
operation. The counter starts to count when the selected CI0 signal is at a high level and
stops counting when the CI0 signal is changed to a low level, here the counter will maintain
its present value and will not be reset.
Figure 9-124. Control circuit in pause mode
CNT_CLK
CNT_REG 52 53 54 55 57 58 59
CI0
TRGIF
CEN
56
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Event mode
After the counter is disabled to count, the counter can resume counting when a CI0 rising
edge signal occurs. When a CI0 rising edge occurs, the counter will start to count from the
current value in the counter. Note that the CI0 signal is only used to enable the counter to
resume counting and has no effect on controlling the counter to stop counting.
Figure 9-125. Control circuit in event mode
CNT_CLK
CNT_REG
CI0
TRGIF
56 57 58 59 5A 5B 5C 5D 5E 5F
CEN
Timer Interconnection
The timers can be internally connected together for timer chaining or synchronization. This
can be implemented by configuring one timer to operate in the Master mode while configuring
another timer to be in the Slave mode. The following figures present several examples of
trigger selection for the master and slave modes.
Figure below shows the TIMER14 trigger selection when it is configured in slave mode.
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Figure 9-126. TIMER14 Master/Slave mode timer example
TIMER14
TIMER 1
Prescaler Counter
Master
mode
control
TIMER 2
Prescaler Counter
Master
mode
control
Trigger
selection
ITI0
ITI1
CI0F_ED
CI0FE0
CI1FE1
ETIF
TRGS
trigger
selection
Slave mode
control Prescaler Counter
TRGO
TRGO
Other interconnection examples:
TIMER1 as prescaler for TIMER14
We configure TIMER1 as a prescaler for TIMER14. Refer to Figure below for connections.
Do as follow:
1. Configure TIMER1 in master mode and select its Update Event (UPE) as trigger output
(MMC=010 in the TIMER1_CTL1 register). Then TIMER1 driver a periodic signal on each
counter overflow.
2. Configure the TIMER1 period (TIMER1_CAR registers).
3. Select the TIMER14 input trigger source from TIMER1 (TRGS=001 in the
TIMER14_SMCFG register).
4. Configure TIMER14 in external clock mode 1 (SMC=111 in TIMER14_SMCFG register).
5. Start TIMER14 by writing ‘1 in the CEN bit (TIMER14_CTL0 register).
6. Start TIMER1 by writing ‘1 in the CEN bit (TIMER1_CTL0 register).
Start TIMER14 with TIMER1’s Enable/Update signal
First, we enable TIMER14 with the enable out of TIMER1. Refer to Figure below. TIMER14
starts counting from its current value on the divided internal clock after trigger by TIMER1
enable output.
When TIMER14 receives the trigger signal its CEN bit is automatically set and the counter
counts until we disable TIMER14. Both counter clock frequencies are divided by 3 by the
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prescaler compared to TIMER_CK (fCNT_CLK = fTIMER_CK /3). Do as follow:
1. Configure TIMER1 master mode to send its enable signal as trigger output(MMC=001 in
the TIMER1_CTL1 register)
2. Configure TIMER14 to select the input trigger from TIMER1 (TRGS=000 in the
TIMER14_SMCFG register).
3. Configure TIMER14 in event mode (SMC=110 in TIMER14_SMCFG register).
4. Start TIMER1 by writing 1 in the CEN bit (TIMER1_CTL0 register).
Figure 9-127. Triggering TIMER14 with Enable of TIMER1
TIMER_CK
TIMER1_CNT_REG
TIMER14_CNT_REG
TIMER1_CEN
61 62 63
11 12 13
TIMER14_TRGIF
14
In this example, we also can use update Event as trigger source instead of enable signal.
Refer to figure below. Do as follow:
1. Configure TIMER1 in master mode and send its Update Event (UPE) as trigger output
(MMC=010 in the TIMER1_CTL1 register).
2. Configure the TIMER1 period (TIMER1_CAR registers).
3. Configure TIMER14 to get the input trigger from TIMER1 (TRGS=001 in the
TIMER14_SMCFG register).
4. Configure TIMER14 in event mode (SMC=110 in TIMER14_SMCFG register).
5. Start TIMER1 by writing ‘1 in the CEN bit (TIMER1_CTL0 register).
Figure 9-128. Triggering TIMER14 with update of TIMER1
TIMER_CK
TIMER1_CNT_REG
TIMER14_CNT_REG
TIMER1_UPE
62
11 12
TIMER14_TRGIF
63 00 01 02
TIMER14_CEN
13 14
Enable TIMER14 count with TIMER1’s enable/O0CPRE signal
In this example, we control the enable of TIMER14 with the enable output of TIMER1 .Refer
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to figure below. TIMER14 counts on the divided internal clock only when TIMER1 is enable.
Both counter clock frequencies are divided by 3 by the prescaler compared to TIMER_CK
(fCNT_CLK = fTIMER_CK). Do as follow:
1. Configure TIMER1 in master mode and Output enable signal as trigger output (MMC=001
in the TIMER1_CTL1 register).
2. Configure TIMER14 to get the input trigger from TIMER1 (TRGS=001 in the
TIMER14_SMCFG register).
3. Configure TIMER14 in pause mode (SMC=101 in TIMER14_SMCFG register).
4. Enable TIMER14 by writing ‘1 in the CEN bit (TIMER14_CTL0 register)
5. Start TIMER14 by writing ‘1 in the CEN bit (TIMER14_CTL0 register).
6. Stop TIMER1 by writing ‘0 in the CEN bit (TIMER1_CTL0 register).
Figure 9-129. Gating TIMER14 with enable of TIMER1
TIMER_CK
TIMER1_CNT_REG
TIMER14_CNT_REG
TIMER1_CEN
61 62 63
11 12 13
TIMER14_TRGIF
In this example, we also can use OxCPRE as trigger source instead of enable signal output.
Do as follow:
1. Configure TIMER1 in master mode and Output Compare 1 Reference (O0CPRE) signal
as trigger output (MMC=100 in the TIMER1_CTL1 register).
2. Configure the TIMER1 O0CPRE waveform (TIMER1_CHCTL0 register).
3. Configure TIMER14 to get the input trigger from TIMER1 (TRGS=001 in the
TIMER0_SMCFG register).
4. Configure TIMER14 in pause mode (SMC=101 in TIMER14_SMCFG register).
5. Enable TIMER14 by writing ‘1 in the CEN bit (TIMER14_CTL0 register).
6. Start TIMER1 by writing ‘1 in the CEN bit (TIMER1_CTL0 register).
Figure 9-130. Gating TIMER14 with O0CPREof TIMER1
TIMER_CK
TIMER1_CNT_REG
TIMER14_TRGIF
TIMER14_CNT_REG
60
TIMER1_O1CPRE
61 62 63 00 01
11 12 13 14
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Using an external trigger to start 2 timers synchronously
We configure the start of TIMER14 is triggered by the enable of TIMER1, and TIMER1 is
triggered by its CI0 input rises edge. To ensure 2 timers start synchronously, TIMER1 must
be configured in Master/Slave mode. Do as follow:
1. Configure TIMER1 slave mode to get the input trigger from CI0 (TRGS=100 in the
TIMER1_SMCFG register).
2. Configure TIMER1 in event mode (SMC=110 in the TIMER1_SMCFG register).
3. Configure the TIMER1 in Master/Slave mode by writing MSC=1 (TIMER1_SMCFG
register).
4. Configure TIMER14 to get the input trigger from TIMER1 (TRGS=001 in the
TIMER14_SMCFG register).
5. Configure TIMER14 in event mode (SMC=110 in the TIMER14_SMCFG register).
When a rising edge occurs on TIMER1’s CI0, two timer counters starts counting
synchronously on the internal clock and both TRGIF flags are set.
Figure 9-131. Triggering TIMER14 and TIMER1 with TIMER1’s CI0 input
TIMER_CK
TIMER1_CNT_REG
TIMER14_CNT_REG
TIMER1_CI0
00 01
TIMER1_CEN
TIMER1_CK
02 03
00 01 02 03
TIMER14_CK
TIMER1_TRGIF
TIMER14_CEN
TIMER14_TRGIF
Timer debug mode
When the Cortex™-M3 halted, and the DBG_TIMERx_STOP configuration bit in DBG module
set to 1, the TIMERx counter stops.
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9.5.4. TIMER14 registers
Control register 0 (TIMERx_CTL0)
Address offset: 0x00
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
CKDIV[1:0]
ARSE
Reserved
SPM
UPS
UPDIS
CEN
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
15:10
Reserved
Must be kept at reset value
9:8
CKDIV[1:0]
Clock division
The CKDIV bits can be configured by software to specify division ratio between the
timer clock (TIMER_CK) and the dead-time and sampling clock (DTS), which is
used by the dead-time generators and the digital filters.
00: fDTS=fTIMER_CK
01: fDTS= fTIMER_CK /2
10: fDTS= fTIMER_CK /4
11: Reserved
7
ARSE
Auto-reload shadow enable
0: The shadow register for TIMERx_CAR register is disabled
1: The shadow register TIMERx_CAR register is enabled
6:4
Reserved
Must be kept at reset value
3
SPM
Single pulse mode.
0: Counter continues after update event.
1: The CEN is cleared by hardware and the counter stops at next update event.
2
UPS
Update source
This bit is used to select the update event sources by software.
0: When enabled, any of the following events generate an update interrupt or DMA
request:
– The UPG bit is set
– The counter generates an overflow or underflow event
– The slave mode controller generates an update event.
1: When enabled, only counter overflow/underflow generates an update interrupt or
DMA request.
1
UPDIS
Update disable
This bit is used to enable or disable the update event generation.
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0: update event enable. The update event is generate and the buffered registers are
loaded with their preloaded values when one of the following events occurs:
– The UPG bit is set
– The counter generates an overflow or underflow event
– The slave mode controller generates an update event.
1: update event disable. The buffered registers keep their value, while the counter
and the prescaler are reinitialized if the UPG bit is set or if the slave mode controller
generates a hardware reset event.
0
CEN
Counter enable
0: Counter disable
1: Counter enable
The CEN bit must be set by software when timer works in external clock, pause
mode and encoder mode. While in event mode, the hardware can set the CEN bit
automatically.
Control register 1 (TIMERx_CTL1)
Address offset: 0x04
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
ISO1
ISO0N
ISO0
Res.
MMC[2:0]
DMAS
CCUC
Res.
CCSE
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
15:11
Reserved
Must be kept at reset value
10
ISO1
Idle state of channel 1 output
Refer to ISO0 bit
9
ISO0N
Idle state of channel 0 complementary output
0: When POEN bit is reset, CH0_ON is set low
1: When POEN bit is reset, CH0_ON is set high
This bit can be modified only when PROT[1:0] bits in TIMERx_CCHP register is 00.
8
ISO0
Idle state of channel 0 output
0: When POEN bit is reset, CH0_O is set low
1: When POEN bit is reset, CH0_O is set high
The CH0_O output changes after a dead-time if CH0_ON is implemented. This bit
can be modified only when PROT[1:0] bits in TIMERx_CCHP register is 00.
7
Reserved
Must be kept at reset value
6:4
MMC[2:0]
Master mode control
These bits control the selection of TRGO signal, which is sent in master mode to
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slave timers for synchronization function.
000: Reset. When the UPG bit in the TIMERx_SWEVG register is set or a reset is
generated by the slave mode controller, a TRGO pulse occurs. And in the latter
case, the signal on TRGO is delayed compared to the actual reset.
001: Enable. This mode is useful to start several timers at the same time or to
control a window in which a slave timer is enabled. In this mode the master mode
controller selects the counter enable signal TIMERx_EN as TRGO. The counter
enable signal is set when CEN control bit is set or the trigger input in pause mode is
high. There is a delay between the trigger input in pause mode and the TRGO
output, except if the master-slave mode is selected.
010: Update. In this mode the master mode controller selects the update event as
TRGO.
011: Capture/compare pulse.In this mode the master mode controller generates a
TRGO pulse when a capture or a compare match occurred.
100: Compare.In this mode the master mode controller selects the O0CPRE signal
is used as TRGO
101: Compare.In this mode the master mode controller selects the O1CPRE signal
is used as TRGO
110: Compare.In this mode the master mode controller selects the O2CPRE signal
is used as TRGO
111: Compare.In this mode the master mode controller selects the O3CPRE signal
is used as TRGO
3
DMAS
DMA request source selection
0: DMA request of channel x is sent when capture/compare event occurs
1: DMA request of channel x is sent when update event occurs
2
CCUC
Commutation control shadow register update control
When the Commutation control shadow registers (for CHxEN, CHxNEN and
CHxCOMCTL bits) are enabled (CCSE=1), this bit control when these shadow
registers update.
0: The shadow registers update by when CMTG bit is set
1: The shadow registers update by when CMTG bit is set or a rising edge of TRGI
occurs
When a channel does not have a complementary output, this bit has no effect.
1
Reserved
Must be kept at reset value
0
CCSE
Commutation control shadow register enable
0: The shadow registers for CHxEN, CHxNEN and CHxCOMCTL bits are disabled
1: The shadow registers for CHxEN, CHxNEN and CHxCOMCTL bits are
enabled.After these bits have been written, they are updated only when CMTG bit is
set
When a channel does not have a complementary output, this bit has no effect.
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Slave mode configuration register (TIMERx_SMCFG)
Address offset: 0x08
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
MSM
TRGS[2:0]
Res.
SMC[2:0]
rw
rw
rw
Bits
Fields
Descriptions
15:8
Reserved
Must be kept at reset value
7
MSM
Master-slave mode
The effect of an event on the trigger input is delayed in this mode to allow a perfect
synchronization between the current timer and its slaves through TRGO. If we want
to synchronize several timers on a single external event, this mode can be used.
0: Master-slave mode disable
1: Master-slave mode enable
6:4
TRGS[2:0]
Trigger selection
This bit-field specifies which signal is selected as the trigger input, which is used to
synchronize the counter.
000: Internal trigger input 0 (ITI0) TIMER1
001: Internal trigger input 1 (ITI1) TIMER2
010: Internal trigger input 2 (ITI2) Res
011: Internal trigger input 3 (ITI3) Res
100: CI0 edge flag (CI0F_ED)
101: Filtered channel 0 input (CI0FE0)
110: Filtered channel 1 Input (CI1FE1)
111: External trigger input (ETIF)
These bits must not be changed when slave mode is enabled.
3
Reserved
Must be kept at reset value
2:0
SMC[2:0]
Slave mode control
000: Disable mode.The prescaler is clocked directly by the internal clock when CEN
bit is set high
001: Reserved
010: Reserved
011: Reserved
100: Restart Mode. The counter is reinitialized and the shadow registers are updated
on the rising edge of the selected trigger input.
101: Pause Mode. The trigger input enables the counter clock when it is high and
disables the counter when it is low.
110: Event Mode. A rising edge of the trigger input enables the counter. The counter
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cannot be disabled by the slave mode controller.
111: External Clock Mode 0.The counter counts on the rising edges of the selected
trigger.
Because CI0F_ED outputs 1 pulse for each transition on CI0F, and the pause mode
checks the level of the trigger signal, when CI0F_ED is selected as the trigger input,
the pause mode must not be used.
DMA and interrupt enable register (TIMERx_DMAINTEN)
Address offset: 0x0C
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Res
TRGDEN
Reserved
CH1DEN
CH0DEN
UPDEN
BRKIE
TRGIE
CMTIE
Reserved
CH1IE
CH0IE
UPIE
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
15
Reserved
Must be kept at reset value.
14
TRGDEN
Trigger DMA request enable
0: Trigger DMA request disabled
1: Trigger DMA request enabled
13:11
Reserved
Must be kept at reset value.
10
CH1DEN
Channel 1 Capture/Compare DMA request enable
0: Channel 1 Capture/Compare DMA request disabled
1: Channel 1 Capture/Compare DMA request enabled
9
CH0DEN
Channel 0 Capture/Compare DMA request enable
0: Channel 0 Capture/Compare DMA request disabled
1: Channel 0 Capture/Compare DMA request enabled
8
UPDEN
Update DMA request enable
0: Update DMA request disabled
1: Update DMA request enabled
7
BRKIE
Break interrupt enable
0: Break interrupt disabled
1: Break interrupt enabled
6
TRGIE
Trigger interrupt enable
0: Trigger interrupt disabled
1: Trigger interrupt enabled
5
CMTIE
CMT interrupt enable
0: CMT interrupt disabled
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1: CMT interrupt enabled
4:3
Reserved
Must be kept at reset value.
2
CH1IE
Channel 1 Capture/Compare interrupt enable
0: Channel 1 Capture/Compare interrupt disabled
1: Channel 1 Capture/Compare interrupt enabled
1
CH0IE
Channel 0 Capture/Compare interrupt enable
0: Channel 0 Capture/Compare interrupt disabled
1: Channel 0 Capture/Compare interrupt enabled
0
UPIE
Update interrupt enable
0: Update interrupt disabled
1: Update interrupt enabled
Interrupt flag register (TIMERx_INTF)
Address offset: 0x10
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
CH1OF
CH0OF
Res.
BRKIF
TRGIF
CMTIF
Res.
CH1IF
CH0IF
UPIF
rc_w0
rc_w0
rc_w0
rc_w0
rc_w0
rc_w0
rc_w0
rc_w0
Bits
Fields
Descriptions
15:11
Reserved
Must be kept at reset value
10
CH1OF
Channel 1 Capture overflow flag
Refer to CH0OF description
9
CH0OF
Channel 0 Capture overflow flag
When channel 0 is configured in input mode, this flag is set by hardware when a
capture event occurs while CH0IF flag has already been set. This flag is cleared by
software.
0: No Capture overflow interrupt occurred
1: Capture overflow interrupt occurred
8
Reserved
Must be kept at reset value
7
BRKIF
Break interrupt flag
This flag is set by hardware when the break input goes active, and cleared by
software if the break input is not active.
0: No active level break has been detected
1: An active level has been detected
6
TRGIF
Trigger interrupt flag
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This flag is set by hardware on trigger event and cleared by software. When the
slave mode controller is enabled in all modes but pause mode, an active edge on
TRGI input generates a trigger event. When the slave mode controller is enabled in
pause mode both edges on TRGI input generates a trigger event.
0: No trigger event occurred
1: Trigger interrupt occurred
5
CMTIF
Channel commutation interrupt flag
This flag is set by hardware when CMT event occurs, and cleared by software
0: No CMT interrupt occurred
1: CMT interrupt occurred
4:3
Reserved
Must be kept at reset value
2
CH1IF
Channel 1 interrupt enable
Refer to CH0IF description
1
CH0IF
Channel 0 interrupt flag
This flag is set by hardware and cleared by software. When channel 0 is in input
mode, this flag is set when a capture event occurs. When channel 0 is in output
mode, this flag is set when a compare event occurs.
0: No Channel 0 interrupt occurred
1: Channel 0 interrupt occurred
0
UPIF
Update interrupt flag
This bit is set by hardware on an update event and cleared by software.
0: No update interrupt occurred
1: Update interrupt occurred
Software event generation register (TIMERx_SWEVG)
Address offset: 0x14
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
BRKG
TRGG
CMTG
Reserved
CH1G
CH0G
UPG
w
w
w
w
w
w
Bits
Fields
Descriptions
15:8
Reserved
Must be kept at reset value
7
BRKG
Break event generation
This bit is set by software and cleared by hardware automatically. When this bit is
set, the POEN bit is cleared and BRKIF flag is set, related interrupt or DMA transfer
can occur if enabled.
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0: No generate a break event
1: Generate a break event
6
TRGG
Trigger event generation
This bit is set by software and cleared by hardware automatically. When this bit is
set, the TRGIF flag in TIMERx_INTF register is set, related interrupt or DMA
transfer can occur if enabled.
0: No generate a trigger event
1: Generate a trigger event
5
CMTG
Channel commutation event generation
This bit is set by software and cleared by hardware automatically. When this bit is
set the channel control registers (CHxEN, CHxNEN and CHxCOMCTL bits) of the
channels having a complementary output are updated.
0: no generate CMT event
1: generate CMT event
4:3
Reserved
Must be kept at reset value
2
CH1G
Channel 1’s capture or compare event generation
Refer to CH0G description
1
CH0G
Channel 0’s capture or compare event generation
This bit is set by software in order to generate a capture or compare event in
channel 0, it is automatically cleared by hardware. When this bit is set, the CH0IF
flag is set, the corresponding interrupt or DMA request is sent if enabled. In
addition, if channel 0 is configured in input mode, the current value of the counter is
captured in TIMERx_CH0CV register, and the CH0OF flag is set if the CH0IF flag
was already high.
0: No generate a channel 0 capture or compare event
1: Generate a channel 0 capture or compare event
0
UPG
This bit can be set by software, and cleared by hardware automatically. When this
bit is set, the counter is cleared if the center-aligned or upcounting mode is
selected, else (downcounting) it takes the auto-reload value. The prescaler counter
is cleared at the same time.
0: No generate an update event
1: Generate an update event
Channel control register 0 (TIMERx_CHCTL0)
Address offset: 0x18
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
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CH1COM
CEN
CH1COMCTL[
2:0]
CH1COM
SEN
CH1COM
FEN
CH1MS[1
:0]
CH0COM
CEN
CH0COMCTL[
2:0]
CH0COM
SEN
CH0COM
FEN
CH0MS[1
:0]
CH1CAPFLT[3:0]
CH1CAPPSC[1:0]
CH0CAPFLT[3:0]
CH0CAPPSC[1:0]
rw
rw
rw
rw
rw
rw
Output compare mode:
Bits
Fields
Descriptions
15
CH1COMCEN
Channel 1 output compare clear enable
Refer to CH0COMCEN description
14:12
CH1COMCTL[2:0]
Channel 1 output compare mode
Refer to CH0COMCTL description
11
CH1COMSEN
Channel 1 output compare shadow enable
Refer to CH0COMSEN description
10
CH1COMFEN
Channel 1 output compare fast enable
Refer to CH0COMFEN description
9:8
CH1MS[1:0]
Channel 1 mode selection
This bit-field specifies the direction of the channel and the input signal selection.
This bit-field is writable only when the channel is OFF (CH1EN bit in
TIMERx_CHCTL2 register is reset).
00: Channel 1 is configured as output
01: Channel 1 is configured as input, IC1 is connected to CI1FE1
10: Channel 1 is configured as input, IC1 is connected to CI0FE1
11: Channel 1 is configured as input, IC1 is connected to ITS. This mode is
working only if an internal trigger input is selected through TRGS bits in
TIMERx_SMCFG register.
7
CH0COMCEN
Channel 0 output compare clear enable.
When this bit is set, the O0CPRE signal is cleared when High level is detected on
ETIF input.
0: Channel 0 output compare clear disable
1: Channel 0 output compare clear enable
6:4
CH0COMCTL[2:0]
Channel 0 compare output control
This bit-field specifies the behavior of the output reference signal O0CPRE which
drives CH0_O and CH0_ON. O0CPRE is active high, while CH0_O and CH0_ON
active level depends on CH0P and CH0NP bits.
000: Frozen.The O0CPRE signal keep stable, independent of the comparison
between the output compare register TIMERx_CH0CV and the counter.
001: Set high on match.O0CPRE signal is forced high when the counter matches
the output compare register TIMERx_CH0CV.
010: Set low on match. O0CPRE signal is forced low when the counter matches the
c output compare register TIMERx_CH0CV.
011: Toggle on match. O0CPRE toggles when the counter matches the c output
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compare register TIMERx_CH0CV.
100: Force low. O0CPRE is forced low level.
101: Force high. O0CPRE is forced high level.
110: PWM mode 0. When counting up, O0CPRE is high as long as the counter is
smaller than TIMER0_CH0CV else low. When counting down, O0CPRE is low as
long as the counter is larger than TIMERx_CH0CV else high.
111: PWM mode 1. When counting up, O0CPRE is low as long as the counter is
smaller than TIMER0_CH0CV else high. When counting down, O0CPRE is high as
long as the counter is larger than TIMERx_CH0CV else low.
When configured in PWM mode, the O0CPRE level changes only when the output
compare mode switches from “frozen” mode to “PWM” mode or when the result of
the comparison changes.
This bit cannot be modified when PROT[1:0] bit-filed in TIMERx_CCHP register is
11 and CH0MS bit-filed is 00.
3
CH0COMSEN
Channel 0 output compare shadow enable
When this bit is set, the shadow register of TIMER0_CH0CV register, which updates
at each update event will be enabled.
0: Channel 0 output compare shadow disable
1: Channel 0 output compare shadow enable
The PWM mode can be used without validating the shadow register only in one
pulse mode (SPM bit set in TIMERx_CTL0 register is set).
This bit cannot be modified when PROT[1:0] bit-filed in TIMERx_CCHP register is
11 and CH0MS bit-filed is 00.
2
CH0COMFEN
Channel 0 output compare fast enable
When this bit is set, the effect of an event on the trigger in input on the
Capture/Compare output will be accelerated if the channel is configured in PWM0
or PWM1 mode. The output channel will treat an active edge on the trigger input as
a compare match, and CH0_O is set to the compare level independently from the
result of the comparison.
0: Channel 0 output compare fast disable. The minimum delay from an edge on the
trigger input to activate CH0_O output is 5 clock cycles.
1: Channel 0 output compare fast enable. The minimum delay from an edge on the
trigger input to activate CH0_O output is 3 clock cycles.
1:0
CH0MS[1:0]
Channel 0 mode selection
This bit-field specifies the direction of the channel and the input signal selection.
This bit-field is writable only when the channel is OFF (CH0EN bit in
TIMER0_CHCTL2 register is reset).
00: Channel 0 is configured as output.
01: Channel 0 is configured as input, IC0 is connected to CI0FE0.
10: Channel 0 is configured as input, IC0 is connected to CI1FE0.
11: Channel 0 is configured as input, IC0 is connected to ITS. This mode is working
only if an internal trigger input is selected through TRGS bits in TIMERx_SMCFG
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register.
Input capture mode:
Bits
Fields
Descriptions
15:12
CH1CAPFLT[3:0]
Channel 1 input capture filter control
Refer to CH0CAPFLT description
11:10
CH1CAPPSC[1:0]
Channel 1 input capture prescaler
Refer to CH0CAPPSC description
9:8
CH1MS[1:0]
Channel 1 mode selection
This bit-field specifies the direction of the channel and the input signal selection.
This bit-field is writable only when the channel is OFF (CH1EN bit in
TIMERx_CHCTL2 register is reset).
00: Channel 1 is configured as output
01: Channel 1 is configured as input, IC1 is connected to CI1FE1
10: Channel 1 is configured as input, IC1 is connected to CI0FE1
11: Channel 1 is configured as input, IC1 is connected to ITS. This mode is
working only if an internal trigger input is selected through TRGS bits in
TIMERx_SMCFG register.
7:4
CH0CAPFLT[3:0]
Channel 0 input capture filter control
An event counter is used in the digital filter, in which a transition on the output
occurs after N input events. This bit-field specifies the frequency used to sample
CI0 input signal and the length of the digital filter applied to CI0.
0000: Filter disable, fSAMP=fDTS, N=1
0001: fSAMP=fTIMER_CK, N=2
0010: fSAMP= fTIMER_CK, N=4
0011: fSAMP= fTIMER_CK, N=8
0100: fSAMP=fDTS/2, N=6
0101: fSAMP=fDTS/2, N=8
0110: fSAMP=fDTS/4, N=6
0111: fSAMP=fDTS/4, N=8
1000: fSAMP=fDTS/8, N=6
1001: fSAMP=fDTS/8, N=8
1010: fSAMP=fDTS/16, N=5
1011: fSAMP=fDTS/16, N=6
1100: fSAMP=fDTS/16, N=8
1101: fSAMP=fDTS/32, N=5
1110: fSAMP=fDTS/32, N=6
1111: fSAMP=fDTS/32, N=8
3:2
CH0CAPPSC[1:0]
Channel 0 input capture prescaler
This bit-field specifies the ratio of the prescaler on channel 0 input.The prescaler is
reset when CH0EN bit in TIMERx_CHCTL2 register is reset.
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00: Prescaler disable, capture is done on each channel input edge
01: Capture is done every 2 channel input edges
10: Capture is done every 4channel input edges
11: Capture is done every 8 channel input edges
1:0
CH0MS[1:0]
Channel 0 mode selection
This bit-field specifies the direction of the channel and the input signal selection.
This bit-field is writable only when the channel is OFF (CH0EN bit in
TIMERx_CHCTL2 register is reset).
00: Channel 0 is configured as output
01: Channel 0 is configured as input, IC0 is connected to CI0FE0
10: Channel 0 is configured as input, IC0 is connected to CI1FE0
11: Channel 0 is configured as input, IC0 is connected to ITS. This mode is
working only if an internal trigger input is selected through TRGS bits in
TIMERx_SMCFG register.
Channel control register 2 (TIMERx_CHCTL2)
Address offset: 0x20
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
CH1NP
Res.
CH1P
CH1EN
CH0NP
CH0NEN
CH0P
CH0EN
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
15:8
Reserved
Must be kept at reset value
7
CH1NP
Channel 1 complementary output polarity
Refer to CH0NP description
6
Reserved
Must be kept at reset value
5
CH1P
Channel 1 polarity
Refer to CH0P description
4
CH1EN
Channel 1 enable
Refer to CH0EN description
3
CH0NP
Channel 0 complementary output polarity
When channel 0 is configured in output mode, this bit specifies the complementary
output signal polarity.
0: Channel 0 active high
1: Channel 0 active low
This bit cannot be modified when PROT[1:0] bit-filed in TIMERx_CCHP register is
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11 or 10.
2
CH0NEN
Channel 0 complementary output enable
When channel 0 is configured in output mode, setting this bit enables the
complementary output in channel 0.
0: Channel 0 complementary output disabled
1: Channel 0 complementary output enabled
1
CH0P
Channel 0 polarity
When channel 0 is configured in input mode, this bit specifies the CI0 signal
polarity. When channel 0 is configured in output mode, this bit specifies the output
signal polarity.
0: Channel 0 active high
1: Channel 0 active low
This bit cannot be modified when PROT[1:0] bit-filed in TIMERx_CCHP register is
11 or 10.
0
CH0EN
Channel 0 enable
When channel 0 is configured in input mode, setting this bit enables CH0_O signal
in active state. When channel 0 is configured in output mode, setting this bit enables
the capture event in channel 0.
0: Channel 0 disabled
1: Channel 0 enabled
Counter register (TIMERx_CNT)
Address offset: 0x24
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
CNT[15:0]
rw
Bits
Fields
Descriptions
15:0
CNT[15:0]
This bit-filed indicates the current counter value. Writing to this bit-filed can change
the value of the counter.
Prescaler register (TIMERx_PSC)
Address offset: 0x28
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
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PSC[15:0]
rw
Bits
Fields
Descriptions
15:0
PSC[15:0]
Prescaler value of the counter clock
The PSC clock is divided by (PSC+1) to generate the counter clock. The value of
this bit-filed will be loaded to the corresponding shadow register at every update
event.
Counter auto reload register (TIMERx_CAR)
Address offset: 0x2C
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
CAR[15:0]
rw
Bits
Fields
Descriptions
15:0
CAR[15:0]
Counter auto reload value
This bit-filed specifies the auto reload value of the counter.
Counter repetition register (TIMERx_CREP)
Address offset: 0x30
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
CREP[7:0]
rw
Bits
Fields
Descriptions
15:8
Reserved
Must be kept at reset value.
7:0
CREP[7:0]
Counter repetition value
This bit-filed specifies the update event generation rate. Each time the repetition
counter counting down to zero, an update event is generated. The update rate of
the shadow registers is also affected by this bit-filed when these shadow registers
are enabled.
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Channel 0 capture/compare value register (TIMERx_CH0CV)
Address offset: 0x34
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
CH0VAL[15:0]
rw
Bits
Fields
Descriptions
15:0
CH0VAL[15:0]
Capture or compare value of channel 0
When channel 0 is configured in input mode, this bit-filed indicates the counter
value corresponding to the last capture event. And this bit-filed is read-only.
When channel 0 is configured in output mode, this bit-filed contains value to be
compared to the counter. When the corresponding shadow register is enabled, the
shadow register updates every update event.
Channel 1 capture/compare value register (TIMERx_CH1CV)
Address offset: 0x38
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
CH1VAL[15:0]
rw
Bits
Fields
Descriptions
15:0
CH1VAL[15:0]
Capture or compare value of channel 1
When channel 1 is configured in input mode, this bit-filed indicates the counter
value corresponding to the last capture event. And this bit-filed is read-only.
When channel 1 is configured in output mode, this bit-filed contains value to be
compared to the counter. When the corresponding shadow register is enabled, the
shadow register updates every update event.
Complementary Channel Protection register (TIMERx_CCHP)
Address offset: 0x44
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
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POEN
OAEN
BRKP
BRKEN
ROS
IOS
PROT[1:0]
DTCFG[7:0]
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
15
POEN
Primary output enable
This bit s set by software or automatically by hardware depending on the OAEN bit.
It is cleared asynchronously by hardware assoon as the break input is active. When
a channel is configured in output mode, setting this bit enables the channel outputs
(CHx_O and CHx_ON) if the corresponding enable bits (CHxEN, CHxNEN in
TIMERx_CHCTL2 register) have been set.
0: Channel outputs are disabled or forced to idle state.
1: Channel outputs are enabled.
14
OAEN
Output automatic enable
This bit specifies whether the POEN bit can be set automatically by hardware.
0: POEN can be not set by hardware.
1: POEN can be set by hardware automatically at the next update event,if the break
input is notactive.
This bit can be modified only when PROT[1:0] bit-filed in TIMERx_CCHP register is
00.
13
BRKP
Break polarity
This bit specifies the polarity of the BRK input signal.
0: BRK input active low
1: BRK input active high
12
BRKEN
Break enable
This bit can be set to enable the BRK and CCS clock failure event inputs.
0: Break inputs disabled
1: Break inputs enabled
This bit can be modified onlywhen PROT[1:0] bit-filed in TIMERx_CCHP register is
00.
11
ROS
Run mode off-state configure
When POEN bit is set, this bit specifies the output state for the channels which has
a complementary output and has been configured in output mode.
0: When POEN bit is set, the channel output signals (CHx_O/CHx_ON) are
disabled.
1: When POEN bit is set, he channel output signals (CHx_O/CHx_ON)are enabled,
with relationship to CHxEN/CHxNEN bits in TIMERx_CHCTL2 register.
This bit cannot be modified when PROT[1:0] bit-filed in TIMERx_CCHP register is
10 or 11.
10
IOS
Idle mode off-state configure
When POEN bit is reset, this bit specifies the output state for the channels which
has been configured in output mode.
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0: When POEN bit is reset, the channel output signals (CHx_O/CHx_ON) are
disabled.
1: When POEN bit is reset, the channel output signals (CHx_O/CHx_ON) are
enabled, with relationship to CHxEN/CHxNEN bits in TIMERx_CHCTL2 register.
This bit cannot be modified when PROT[1:0] bit-filed in TIMERx_CCHP register is
10 or 11.
9:8
PROT[1:0]
Complementary register protect control
This bit-filed specifies the write protection property of registers.
00: protect disable. No write protection.
01: PROT mode 0.The ISOx/ISOxN bits in TIMERx_CTL1 register and the
BRKEN/BRKP/OAEN/DTCFG bits in TIMERx_CCHP register are writing protected.
10: PROT mode 1. In addition of the registers in PROT mode 0, the CHxP/CHxNP
bits in TIMERx_CHCTL2 register (if related channel is configured in output mode)
and the ROS/IOS bits in TIMERx_CCHP register are writing protected.
11: PROT mode 2. In addition of the registers in PROT mode 1, the
CHxCOMCTL/CHxCOMSEN bits in TIMERx_CHCTLx registers (if the related
channel is configured in output) are writing protected.
This bit-field can be written only once after the reset. Once the TIMERx_CCHP
register has been written, this bit-field will be writing protected.
7:0
DTCFG[7:0]
Dead time configure
This bit-field specifies the duration of the dead-time, which is inserted before the
output transitions. The relationship between DTCFG value and the duration of dead-
time is as follow:
DTCFG [7:5]=0xx: duration =DTCFG[7:0]x tDT, tDT=tDTS.
DTCFG [7:5]=10x:duration =(64+DTCFG[5:0])xtDT,tDT=tDTS*2.
DTCFG [7:5]=110: duration =(32+DTCFG[4:0])xtDT, tDT=tDTS*8.
DTCFG [7:5]=111:duration =(32+DTCFG[4:0])xtDT,tDT=tDTS*16.
This bit can be modified only when PROT[1:0] bit-filed in TIMERx_CCHP register is
00.
DMA configuration register (TIMERx_DMACFG)
Address offset: 0x48
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
DMATC[4:0]
Reserved
DMATA[4:0]
rw
rw
Bits
Fields
Descriptions
15:14
Reserved
Must be kept at reset value
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12:8
DMATC[4:0]
DMA transfer count
When register access are done through the TIMERx_DMATB address, this 5-bit bit-
field specifies the number of transfers.
7:5
Reserved
Must be kept at reset value
4:0
DMATA[4:0]
DMA transfer access start address
When register access are done through the TIMERx_DMATB address, this bit-field
specifies the offset of the starting address from the TIMERx_CTL0 register.
DMA Transfer buffer register (TIMERx_DMATB)
Address offset: 0x4C
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
DMATB[15:0]
rw
Bits
Fields
Descriptions
15:0
DMATB[15:0]
DMA transfer
When a read or write operation is assigned to this register, the register located at
the address range (DMATA + burst counter) x 4 from TIMERx_CTL0 will be
accessed.
The burst counter is calculated by hardware, and ranges from 0 to DMATC.
Configuration register (TIMERx_CFG) of GD32F170xx and GD32F190xx
devices
Address offset: 0xFC
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
CCSEL
OUTSEL
rw
rw
Bits
Fields
Descriptions
15:2
Reserved
Must be kept at reset value
1
CCSEL
Write Capture/Compare register selection
This bit-field set and reset by software.
1: If write the Capture/Compare register, the write value is same as the
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Capture/Compare value, the write access ignored
0: No effect
0
OUTSEL
The output value selection.
This bit-field set and reset by software.
1: If POEN and IOS is 0, the output disabled
0: No effect
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9.6. General timer (TIMER15/TIMER16)
9.6.1. Introduction
The general timer, known as TIMER15/TIMER16, may be used for a variety of purposes. It
consists of one 16-bit up-counter; one 16-bit capture/compare register (TIMERx_CH0CV),
one 16-bit counter auto reload register (TIMERx_CAR) and several control registers. They
can be used for a variety of purposes including general timer, input signal pulse width
measurement or output waveform generation such as single pulse generation or PWM output.
The general (TIMER15/TIMER16) timers are completely independent. They do not share any
resources but can be synchronized together.
9.6.2. Main features
16-bit up auto-reload counter.
16-bit programmable prescaler that allows division of the counter clock frequency by any
factor between 1 and 65536.
1 independent channel supports functions including input capture, compare match output,
generation of PWM waveform (edge and center-aligned Mode), and single pulse mode
output.
Counter repetition to update the timer registers only after a given number of cycles of the
counter.
Break input to trigger the timer’s output signals to a known state.
Interrupt/DMA generation by update, trigger event, input capture event, output compare
match event or break input
Programmable dead-time for output match.
9.6.3. Function description
Figure below provides details on the internal configuration of the advanced timer.
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322
Figure 9-132. Gereral timer block diagram (TIMER15/16)
Counter Control
TIMER15_CK
CH0
BRKIN Polarity Selection
Input Filter Edge Detector Prescaler
Capture Register
Compare Register
Prescaler
Counter
AutoReload
Register
Repetition
counter
Repeat
Register
DTG Output
Control
CH0
CH0_N
Prescaler counter
The prescaler can divide the timer clock (TIMER_CK) to the counter clock (CNT_CLK) by any
factor between 1 and 65536. It is controlled through prescaler register (TIMERx_PSC) which
can be changed on the fly but be taken into account at the next update event.
Figure 9-133. Counter timing diagram with prescaler division change from 1 to 2
TIMER_CK
CEN
CNT_CLK
CNT_REG
Reload Pulse
Prescaler CNT
Prescaler BUF
Prescaler CR
F7 F8 F9 FA FB FC 01 02 03 04
01
0 1
0 0 1 0 1 0 1 0 1
modify scaler Vaule
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Figure 9-134. Counter timing diagram with prescaler division change from 1 to 4
TIMER_CK
CEN
CNT_CLK
CNT_REG
Reload Pulse
Prescaler CNT
Prescaler BUF
Prescaler CR
F7 F8 F9 FA FB FC 00 01
03
0 3
0 0 1 2 3 0 1 2 3
modify PSC Vaule
Upcounting mode
In this mode the counter counts continuously from 0 to the counter-reload value, which is
defined in the TIMERx_CAR register, in a count-up direction. Once the counter reaches the
counter reload value, the counter restarts to count once again from 0. If the repetition counter
is set, the update eventis generated after the number of overflow. Else the update event is
generated at each counter overflow.
When the update event is set by the UPG bit in the TIMERx_SWEVG register, the counter
value will be initialized to 0 and generates an update event.
If set the UPDIS bit in TIMERx_CTL0 register, the update event is disabled.
When an update event occurs, all the registers (repetition counter, autoreload register,
prescaler register) are updated.
The following figures show some examples of the counter behavior for different clock
frequencies when TIMERx_CAR=0x63.
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Figure 9-135. Counter timing diagram, internal clock divided by 1
TIMER_CK
CEN
CNT_CLK
CNT_REG
overflow
5E 5F 60 61 62 63 00 01 02 03 04 05 06 07
Update event (UPE)
Update interrupt flag (UPIF)
Figure 9-136. Counter timing diagram, internal clock divided by 2
TIMER_CK
CEN
CNT_CLK
CNT_REG
overflow
61
Update event (UPE)
Update interrupt flag (UPIF)
62 63 00 01 02 03 04
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Figure 9-137. Counter timing diagram, internal clock divided by 4
TIMER_CK
CEN
CNT_CLK
CNT_REG
overflow
62
Update event (UPE)
Update interrupt flag (UPIF)
63 00 01
Figure 9-138. Counter timing diagram, internal clock divided by N
TIMER_CK
CNT_CLK
CNT_REG
overflow
31
Update event (UPE)
Update interrupt flag (UPIF)
32 00
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Figure 9-139. Counter timing diagram, update event when ARSE=0
TIMER_CK
CEN
CNT_CLK
CNT_REG
overflow
5E 5F 60 61 62 63 00 01 02 03 04 05 06 07
Update event (UPE)
Update interrupt flag (UPIF)
Auto-reload register 65 63
modify CAR Vaule
Figure 9-140. Counter timing diagram, update event when ARSE=1
TIMER_CK
CEN
CNT_CLK
CNT_REG
overflow
60 61 62 63 64 65 00 01 02 03 04 05 06 07
Update event (UPE)
Update interrupt flag (UPIF)
Auto-reload register 65 63
modify CAR Vaule
Auto-reload shadow register 65 63
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Counter Repetition
Counter Repetition is used to generator update event or updates the timer registers only after
a given number (N+1) of cycles of the counter, where N is CREP in TIMERx_CREP register.
The repetition counter is decremented at each counter overflow in up-counting mode, at each
counter underflow in down-counting mode or at each counter overflow and at each counter
underflow in center-aligned mode.
Setting the UPG bit in the TIMERx_SWEVG register will reload the content of CREP in
TIMERx_CREP register and generator an update event.
Figure 9-141. Update rate examples depending on mode and TIMERx_CREP
TIMER15/TIMER16 has only upcounting edge-aligned mode.
Center-aligned mode Upcounting
Edge-aligned mode
Downcounting
Edge-aligned mode
CREP = 0
CREP = 1
Clock selection
The following describes the Timer Module clock controller which determines the clock source
of the internal prescaler counter.
Internal timer clock TIMER_CK
The only clock source is the TIMER_CK clock.
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328
Figure 9-142. Control circuit in normal mode, internal clock divided by 1
TIMER_CK
CEN
CNT_CLK
CNT_REG
Reload Pulse
17 18 19 20 21 22
UPG
23 00 01 02 03 04 05 06
Capture/compare channels
The TIMER15/TIMER16 has one independent channel which can be used as capture inputs
or compare match outputs. Each channel is built around a channel capture/compare value
register including an input stage, channel controller and an output stage.
Input capture stage
The input stage consists of a digital filter, a channel polarity selection, edge detection and a
channel prescaler. The channel input signal (CIx) is sampled by a digital filter to generate a
filtered input signal CIxF. Then the channel polarity and the edge detection block can generate
a CIxFEx signal for the input capture function. The effective input event number can be set
by the channel input prescaler (CHxCAPPSC).
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329
Figure 9-143. Capture/compare channel (example: channel 0 input stage)
filter
downcounter
CI0
CH0CAPFLT
[3:0]
CHCTL0
fDTS
Edge Detector CI0F_Falling
CI0F_Rising 0
1
CH0P/
CH0NP
CHCTL2
01
CH0MS[ 1:0 ]
CHCTL0
10
11
CI0FE0
CI1FE0
ITS
divider
/1, /2, /4, /8
CH0CAPPS
C[1:0]
CHCTL0
CH0EN
CHCTL2
IC0
Channel controller
The GPTM has one independent channels which can be used as capture inputs or compare
match outputs.
When used in the input capture mode, the counter value is captured into the TIMERx_CHxCV
shadow register first and then transferred into the TIMERx_CHxCV preload register when the
capture event occurs.
When used in the compare match output mode, the contents of the TIMERx_CHxCV preload
register is copied into the associated shadow register; the counter value is then compared
with the register value.
Figure 9-144. Capture/compare channel 0 main circuit
APB BUS
MCU-peripheral interface
Capture/compare preload register
Capture/compare shadow
register
Counter
CH0VAL
CH0MS[0]
CH0MS[1]
CH0CAPPSC
CH0EN
CH0G
TIMER_SWEVG
CH0VAL
CH0MS[0]
CH0MS[1]
CH0COMSEN
UPE
CNT>CH0VAL
CNT=CH0VAL
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Output stage
The TIMER15/TIMER16 has one channels for compare match, single pulse or PWM output
function.
Figure 9-145. Output stage of capture/compare channel (channel 0)
Output mode controller
CNT>CH0VAL
CNT=CH0VAL
CH0COMCTL
[2:0]
CHCTL0
ETI
0
1
CH0NP
CHCTL2
11
CH0MS[ 1:0 ]
CHCTL0
10
x0
Dead-time
generator
DTCFG
[7:0]
CCHP
x0
CH0MS[ 1:0 ]
CHCTL0
10
11
0
1
CH0P
CHCTL2
Output
enable
circuit
CHx_O
Output
enable
circuit
CHx_ON
CH0NEN
CHCTL2
POEN
CCHP ROS IOS
CH0EN
CHCTL2
CH0COM
CEN
Input Capture Mode
When the channel is used as a capture input, the counter value is captured into the Channel
Capture/Compare Register (TIMERx_CHxCV) when an effective input signal transition occurs.
Once the capture event occurs, the CHxIF flag in the TIMERx_INTF register is set. If the
CHxIF bit is already set, i.e., the flag has not yet been cleared by software, and another
capture event on this channel occurs, the corresponding channel Over-Capture flag, named
CHxOF, will be set.Once the capture event occurs, a DMA request is generated depending
on the CHxDEN bit and an interrupt is generated depending on the CHxIE bit. The fllowing
step maybe used to implement input capture mode:
Select input signal by set CHxMS bits in the channel control register (TIMERx_CHCTLx).
Add input filter to input signal by set CHxCAPFLT bitst in the the channel control register
(TIMERx_CHCTLx).
Select input capture edge (rising or falling) by set CHxP/CHxNP bit in the channel control
register 2 (TIMERx_CHCTL2).
If input signal need prescaler, set CHxCAPPSC bits in the the channel control register
(TIMERx_CHCTLx).
If need interrupt, set CHxIE bit in DMA and interrupt enable register
(TIMERx_DMAINTEN) to 1.
If need DMA request, set CHxDEN bit in DMA and interrupt enable register
(TIMERx_DMAINTEN) to 1.
Enable the channel by set CHxEN bit in the channel control register 2 (TIMERx_CHCTL2)
to 1.
After configure this registers, the input capture event on this channel may occurs at the
corresponding edge. And the counter value is captured into the Channel Capture/Compare
Register (TIMERx_CHxCV). An interrupt generated if CHxIE bit set. A DMA request
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331
generated if CHxDEN set.
The input capture mode can be also used for pulse width measurement from signals on the
TIMERx_CHx pins (CIx). For example, PWM signal connect to CI0 input. Select channel 0
capture signal to CI0 by setting CH0MS to 01 in the channel control register
(TIMERx_CHCTL0) and set capture on rising edge. Select channel 1 capture signal to CI0 by
setting CH1MS to 10 in the channel control register (TIMERx_CHCTL0) and set capture on
falling edge. The counter set to restart mode and restart on channel 0 rising edge. Then the
TIMERx_CH0CV can measure the PWM period and the TIMERx_CH1CV can measure the
PWM duty.
Output Compare Mode/PWM Mode
When the channel is used as an output mode by setting the CHxMS in the the channel control
register (TIMERx_CHCTLx) to 00, the channel outputs waveform according to the
CHxCOMCTL bits in the the the channel control register (TIMERx_CHCTLx), and the
comparision between the counter and TIMERx_CHxCV registers. When the comparision
equals, the CHxIF flag in the Interrupt flag registers (TIMERx_INTF) set to 1. A DMA request
is generated depending on the CHxDEN bit and an interrupt is generated depending on the
CHxIE bit.
In output mode, the channel can outputs active level by set the CHxCOMCTL to 101, and
outputs inactive level by set the CHxCOMCTL bits to 100.
In ouput mode, the channel output set to active level when the comparision between the
counter and TIMERx_CHxCV registers match, by set the CHxCOMCTL to 001. The channel
output set to inactive level when the comparision between the counter and TIMERx_CHxCV
registers match, by set the CHxCOMCTL to 010.
In output compare toggle mode (by set the CHxCOMCTL to 011), the channel output toggles
when the comparision between the counter and TIMERx_CHxCV registers match.
Figure 9-146. Output compare toggle mode, toggle on CH0_O
CNT_REG
O0CPRE=CH0_O
003A0039
CH0VAL
003B B200 B201
003A B201
Match detected on CH0VAL
Interrupt generated if enabled
Write B201h in the CH0VAL
register
In the output PWM mode (by setting the CHxCOMCTL bits to 110 (PWM mode 0) or to 111
(PWM mode 1)), the channel can outputs PWM waveform according to the TIMERx_CAR
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332
registers and TIMERx_CHxCV registers.
Figure 9-147. Output compare PWM mode 0 on CH0_O, upcounting mode
CNT_REG
O0CPRE=CH0_O
003A0039
CH0VAL
003B 100 0
003A
Match detected on CH0VAL
Interrupt generated if enabled
Figure 9-148. Output compare PWM mode 0 on CH0_O, center-aligned counting mode
CNT_REG
O0CPRE=CH0_O
003A0039
CH0VAL
003B 0100 00FF
003A
Match detected on CH0VAL
Interrupt generated if enabled
00FE 003B 003A 0039
Channel Output Reference Signal
When the TIMER15/TIMER16 is used in the compare match output mode, the OxCPRE signal
(Channel x Output Reference signal) is defined by setting the CHxCOMCTL bits. The
OxCPRE signal has several types of output function. These include, keeping the original level
by setting the CHxCOMCTL field to 0x00, set to 1 by setting the CHxCOMCTL field to 0x01,
set to 0 by setting the CHxCOMCTL field to 0x02 or signal toggle by setting the CHxCOMCTL
field to 0x03 when the counter value matches the content of the TIMERx_CHxCV register.
The PWM mode 0 and PWM mode 1 outputs are also another kind of OxCPRE output which
is setup by setting the CHxCOMCTL field to 0x06/0x07. In these modes, the OxCPRE signal
level is changed according to the counting direction and the relationship between the counter
value and the TIMERx_CHxCV content. With regard to a more detailed description refer to
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the relative bit definition.
Another special function of the OxCPRE signal is a forced output which can be achieved by
setting the CHxCOMCTL field to 0x04/0x05. Here the output can be forced to an
inactive/active level irrespective of the comparison condition between the counter and the
TIMERx_CHxCV values.
The OxCPRE signal can be forced to 0 when the ETIF signal is derived from the external
TIMERx_ ETI pin and when it is set to a high level by setting the CHxCOMCEN bit to 1 in the
TIMERx_CHCTL0 register. The OxCPRE signal will not return to its active level until the next
update event occurs.
Outputs Complementary and Dead-time
The TIMER15/TIMER16 can output two complementary signals can output by
TIMER15/TIMER16. The complementary signals CHx_O and CHx_ON are activated by a
combination of several control bits: the CHxEN and CHxNEN bits in the TIMERx_CHCTL2
register and the POEN, ISOx, ISOxN, IOS and ROS bits in the TIMERx_CCHP and
TIMERx_CTL1 registers.The outputs polarity are determined by CHxP and CHxNP bits in the
TIMERx_CHCTL2 register
If CHxEN, CHxNEN and POEN bits are 1, dead-time should insertion. The rising edge of
CHx_O output is delayed relative to the rising edge of OxCPRE and the rising edge of
CHx_ON output is delayed relative to the falling edge of OxCPRE.The delay value is a 8-bit
dead-time counter determined by DTCFG field in TIMERx_CCHP register.If the delay value
is greater than the width of the active output (CHx_O or CHx_ON) then the corresponding
pulse is not generated.
Figure 9-149. Complementary output with dead-time insertion.
OxCPRE
CHx_O
CHx_ON
Dead_time
Dead_time
Figure 9-150. Dead-time waveforms with delay greater than the negative pulse
OxCPRE
CHx_O
CHx_ON
Dead_time
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Figure 9-151. Dead-time waveforms with delay greater than the positive pulse
OxCPRE
CHx_ON
CHx_O
Dead_time
Break function
In this function, the output CHx_O and CHx_ON are controlled by the POEN, IOS and ROS
bits in the TIMERx_CCHP register, ISOx and ISOxN bits in the TIMERx_CTL1 register and
cannot be set both to active level when break occurs. The break sources are input break pin
or HXTAL stack event by Clock Monitor (CKM) in RCU. The break function enabled by setting
the BRKEN bit in the TIMERx_CCHP register. The break input polarity is setting by the BRKP
bit in TIMERx_CCHP.
When a break occurs, the POEN bit is cleared asynchronously, the output CHx_O and
CHx_ON are driven with the level programmed in the ISOx bit in the TIMERx_CTL1 register
as soon as POEN is 0. If IOS is 0 then the timer releases the enable output else the enable
output remains high. The complementary outputs are first put in reset state, and then the
dead-time generator is reactivated in order to drive the outputs with the level programmed in
the ISOx and ISOxN bits after a dead-time.
When a break occurs, the BRKIF bit in the TIMERx_INTF register is set.
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Figure 9-152. Output behavior in response to a break（The break input is acting on high
level）
OxCPRE
CHx_O
CHx_O
CHx_O
CHx_O
CHx_O
CHx_ON
CHx_O
CHx_ON
CHx_O
CHx_ON
CHx_O
CHx_ON
CHx_O
CHx_ON
Break_In
CHx_ON not implemented CHxP=0,ISOx=1
CHx_ON not implemented CHxP=0,ISOx=0
CHx_ON not implemented CHxP=1,ISOx=1
CHxEN=1, CHxP=0,ISOx=0,CHxNEN=1,CHxNP=0,ISOxN=1
CHxEN=1, CHxP=0,ISOx=1,CHxNEN=1,CHxNP=1,ISOxN=1
CHxEN=1, CHxP=0,ISOx=0,CHxNEN=0,CHxNP=0,ISOxN=1
CHxEN=1, CHxP=0,ISOx=1,CHxNEN=0,CHxNP=0,ISOxN=0
CHxEN=1, CHxP=0,CHxNEN=0,CHxNP=0,ISOx=0,ISOxN=0 or ISOx=0,ISOxN=1
delay
delaydelaydelay
delay delay
CHx_ON not implemented CHxP=0,ISOx=1
Single Pulse Mode
Once the timer is set to operate in the single pulse mode, it is not necessary to set the timer
enable bit CEN in the TIMERx_CTL0 register to 1 to enable the counter. The trigger to
generate a pulse can be sourced from the trigger signals edge or by setting the CEN bit to 1
using software. Setting the CEN bit to 1 or a trigger from the trigger signals edge can generate
a pulse and then keep the CEN bit at a high state until the update event occurs or the CEN
bit is written to 0 by software. If the CEN bit is cleared to 0 using software, the counter will be
stopped and its value held. If the CEN bit is automatically cleared to 0 by a hardware update
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event, the counter will be reinitialized.
In the Single Pulse mode, the trigger active edge which sets the CEN bit to 1 will enable the
counter. However, there exist several clock delays to perform the comparison result between
the counter value and the TIMERx_CHxCV value. In order to reduce the delay to a minimum
value, the user can set the CHxOFE bit in each TIMERx_CHCTL0 register. After a trigger
rising edge occurs in the single pulse mode, the OxCPRE signal will immediately be forced
to the state which the OxCPRE signal will change to, as the compare match event occurs
without taking the comparison result into account. The CHxOFE bit is available only when the
output channel is configured to operate in the PWM0 or PWM1 output mode and the trigger
source is derived from the trigger signal.
Figure 9-153. Single pulse mode
O0CPRE
CH0_O
CI1
CH0VAL
CARL
T
TIMER_CNT
Timer debug mode
When the Cortex™-M3 halted, and the DBG_TIMERx_STOP configuration bit in DBG module
set to 1, the TIMERx counter stops.
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9.6.4. TIMER15/TIMER16 registers
Control register 0 (TIMERx_CTL0)
Address offset: 0x00
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
CKDIV[1:0]
ARSE
Reserved
SPM
UPS
UPDIS
CEN
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
15:10
Reserved
Must be kept at reset value
9:8
CKDIV[1:0]
Clock division
The CKDIV bits can be configured by software to specify division ratio between the
timer clock (TIMER_CK) and the dead-time and sampling clock (DTS), which is
used by the dead-time generators and the digital filters.
00: fDTS=fTIMER_CK
01: fDTS= fTIMER_CK /2
10: fDTS= fTIMER_CK /4
11: Reserved
7
ARSE
Auto-reload shadow enable
0: The shadow register for TIMERx_CAR register is disabled
1: The shadow register TIMERx_CAR register is enabled
6:4
Reserved
Must be kept at reset value
3
SPM
Single pulse mode.
0: Counter continues after update event.
1: The CEN is cleared by hardware and the counter stops at next update event.
2
UPS
Update source
This bit is used to select the update event sources by software.
0: When enabled, any of the following events generate an update interrupt or DMA
request:
– The UPG bit is set
– The counter generates an overflow or underflow event
– The slave mode controller generates an update event.
1: When enabled, only counter overflow/underflow generates an update interrupt or
DMA request.
1
UPDIS
Update disable.
This bit is used to enable or disable the update event generation.
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0: Update event enable. The update event is generate and the buffered registers
are loaded with their preloaded values when one of the following events occurs:
– The UPG bit is set
– The counter generates an overflow or underflow event
– The slave mode controller generates an update event.
1: Update event disable. The buffered registers keep their value, while the counter
and the prescaler are reinitialized if the UPG bit is set or if the slave mode controller
generates a hardware reset event.
0
CEN
Counter enable
0: Counter disable
1: Counter enable
The CEN bit must be set by software when timer works in external clock, pause
mode and encoder mode. While in event mode, the hardware can set the CEN bit
automatically.
Control register 1 (TIMERx_CTL1)
Address offset: 0x04
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
ISO0N
ISO0
Reserved
DMAS
CCUC
Res.
CCSE
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
15:11
Reserved
Must be kept at reset value
9
ISO0N
Idle state of channel 0 complementary output
0: When POEN bit is reset, CH0_ON is set low
1: When POEN bit is reset, CH0_ON is set high
This bit can be modified only when PROT[1:0] bits in TIMERx_CCHP register is 00.
8
ISO0
Idle state of channel 0 output
0: When POEN bit is reset, CH0_O is set low
1: When POEN bit is reset, CH0_O is set high
The CH0_O output changes after a dead-time if CH0_ON is implemented. This bit
can be modified only when PROT[1:0] bits in TIMERx_CCHP register is 00.
7:4
Reserved
Must be kept at reset value
3
DMAS
DMA request source selection
0: DMA request of channel x is sent when capture/compare event occurs
1: DMA request of channel x is sent when update event occurs
2
CCUC
Commutation control shadow register update control
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When the Commutation control shadow shadow registers (for CHxEN, CHxNEN
and CHxCOMCTL bits) are enabled (CCSE=1), this bit control when these shadow
registers update.
0: The shadow registers update by when CMTG bit is set
1: The shadow registers update by when CMTG bit is set or an rising edge of TRGI
occurs
When a channel does not have a complementary output, this bit has no effect.
1
Reserved
Must be kept at reset value
0
CCSE
Commutation control shadow register enable
0: The shadow registers for CHxEN, CHxNEN and CHxCOMCTL bits are disabled
1: The shadow registers for CHxEN, CHxNEN and CHxCOMCTL bits are
enabled.After these bits have been written, they are updated only when CMTG bit is
set
When a channel does not have a complementary output, this bit has no effect.
DMA and interrupt enable register (TIMERx_DMAINTEN)
Address offset: 0x0C
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
CH0DEN
UPDEN
BRKIE
Res.
CMTIE
Res.
CH0IE
UPIE
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
15:10
Reserved
Must be kept at reset value
9
CH0DEN
Channel 0 Capture/Compare DMA request enable
0: Channel 0 Capture/Compare DMA request disabled
1: Channel 0 Capture/Compare DMA request enabled
8
UPDEN
Update DMA request enable
0: Update DMA request disabled
1: Update DMA request enabled
7
BRKIE
Break interrupt enable
0: Break interrupt disabled
1: Break interrupt enabled
6
Reserved
Must be kept at reset value.
5
CMTIE
CMT interrupt enable
0: CMT interrupt disabled
1: CMT interrupt enabled
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4:2
Reserved
Must be kept at reset value
1
CH0IE
Channel 0 Capture/Compare interrupt enable
0: Channel 0 Capture/Compare interrupt disabled
1: Channel 0 Capture/Compare interrupt enabled
0
UPIE
Update interrupt enable
0: Update interrupt disabled
1: Update interrupt enabled
Interrupt flag register (TIMERx_INTF)
Address offset: 0x10
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
CH0OF
Res.
BRKIF
Res.
CMTIF
Reserved
CH0IF
UPIF
rc_w0
rc_w0
rc_w0
rc_w0
rc_w0
Bits
Fields
Descriptions
15:10
Reserved
Must be kept at reset value
9
CH0OF
Channel 0 Capture overflow flag
When channel 0 is configured in input mode, this flag is set by hardware when a
capture event occurs while CH0IF flag has already been set. This flag is cleared by
software.
0: No Capture overflow interrupt occurred
1: Capture overflow interrupt occurred
8
Reserved
Must be kept at reset value
7
BRKIF
Break interrupt flag
This flag is set by hardware when the break input goes active, and cleared by
software if the break input is not active.
0: No active level break has been detected
1: An active level has been detected
6
Reserved
Must be kept at reset value.
5
CMTIF
Channel commutation interrupt flag
This flag is set by hardware when CMT event occurs, and cleared by software
0: No CMT interrupt occurred
1: CMT interrupt occurred
4:2
Reserved
Must be kept at reset value.
1
CH0IF
Channel 0 interrupt flag
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This flag is set by hardware and cleared by software. When channel 0 is in input
mode, this flag is set when a capture event occurs. When channel 0 is in output
mode, this flag is set when a compare event occurs.
0: No Channel 0 interrupt occurred
1: Channel 0 interrupt occurred
0
UPIF
Update interrupt flag
This bit is set by hardware on an update event and cleared by software.
0: No update interrupt occurred
1: Update interrupt occurred
Software event generation register (TIMERx_SWEVG)
Address offset: 0x14
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
BRKG
Reserved.
CMTG
Reserved
CH0G
UPG
w
w
w
w
Bits
Fields
Descriptions
15:8
Reserved
Must be kept at reset value
7
BRKG
Break event generation
This bit is set by software and cleared by hardware automatically. When this bit is
set, the POEN bit is cleared and BRKIF flag is set, related interrupt or DMA transfer
can occur if enabled.
0: No generate a break event
1: Generate a break event
6
Reserved
Must be kept at reset value.
5
CMTG
Channel commutation event generation
This bit is set by software and cleared by hardware automatically. When this bit is
set the channel control registers (CHxEN, CHxNEN and CHxCOMCTL bits) of the
channels having a complementary output are updated.
0: No generate CMT event
1: Generate CMT event
4:2
Reserved
Must be kept at reset value.
1
CH0G
Channel 0’s capture or compare event generation
This bit is set by software in order to generate a capture or compare event in
channel 0, it is automatically cleared by hardware. When this bit is set, the CH0IF
flag is set, the corresponding interrupt or DMA request is sent if enabled. In
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addition, if channel 0 is configured in input mode, the current value of the counter is
captured in TIMERx_CH0CV register, and the CH0OF flag is set if the CH0IF flag
was already high.
0: No generate a channel 0 capture or compare event
1: Generate a channel 0 capture or compare event
0
UPG
This bit can be set by software, and cleared by hardware automatically. When this
bit is set, the counter is cleared if the center-aligned or upcounting mode is
selected, else (downcounting) it takes the auto-reload value. The prescaler counter
is cleared at the same time.
0: No generate an update event
1: Generate an update event
Channel control register 0 (TIMERx_CHCTL0)
Address offset: 0x18
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
CH0COMCEN
CH0COMCTL[2:0]
CH0COMSEN
CH0COMFEN
CH0MS[1:0]
CH0CAPFLT[3:0]
CH0CAPPSC[1:0]
rw
rw
Output compare mode:
Bits
Fields
Descriptions
15:8
Reserved
Must be kept at reset value.
7
CH0COMCEN
Channel 0 output compare clear enable.
When this bit is set, the O0CPRE signal is cleared when High level is detected on
ETIF input.
0: Channel 0 output compare clear disable
1: Channel 0 output compare clear enable
6:4
CH0COMCTL[2:0]
Channel 0 compare output control
This bit-field specifies the behavior of the output reference signal O0CPRE which
drives CH0_O and CH0_ON. O0CPRE is active high, while CH0_O and CH0_ON
active level depends on CH0P and CH0NP bits.
000: Frozen.The O0CPRE signal keep stable, independent of the comparison
between the output compare register TIMERx_CH0CV and the counter.
001: Set high on match.O0CPRE signal is forced high when the counter matches
the output compare register TIMERx_CH0CV.
010: Set low on match. O0CPRE signal is forced low when the counter matches the
c output compare register TIMERx_CH0CV.
011: Toggle on match. O0CPRE toggles when the counter matches the c output
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compare register TIMERx_CH0CV.
100: Force low. O0CPRE is forced low level.
101: Force high. O0CPRE is forced high level.
110: PWM mode 0. When counting up, O0CPRE is high as long as the counter is
smaller than TIMERx_CH0CV else low. When counting down, O0CPRE is low as
long as the counter is larger than TIMERx_CH0CV else high.
111: PWM mode 1. When counting up, O0CPRE is low as long as the counter is
smaller than TIMERx_CH0CV else high. When counting down, O0CPRE is high as
long as the counter is larger than TIMERx_CH0CV else low.
When configured in PWM mode, the O0CPRE level changes only when the output
compare mode switches from “frozen” mode to “PWM” mode or when the result of
the comparison changes.
This bit cannot be modified when PROT[1:0] bit-filed in TIMERx_CCHP register is
11 and CH0MS bit-filed is 00.
3
CH0COMSEN
Channel 0 output compare shadow enable
When this bit is set, the shadow register of TIMERx_CH0CV register, which updates
at each update event will be enabled.
0: Channel 0 output compare shadow disable
1: Channel 0 output compare shadow enable
The PWM mode can be used without validating the shadow register only in one
pulse mode (SPM bit set in TIMERx_CTL0 register is set).
This bit cannot be modified when PROT[1:0] bit-filed in TIMERx_CCHP register is
11 and CH0MS bit-filed is 00.
2
CH0COMFEN
Channel 0 output compare fast enable
When this bit is set, the effect of an event on the trigger in input on the
Capture/Compare output will be accelerated if the channel is configured in PWM0
or PWM1 mode. The output channel will treat an active edge on the trigger input as
a compare match, and CH0_O is set to the compare level independently from the
result of the comparison.
0: Channel 0 output compare fast disable. The minimum delay from an edge on the
trigger input to activate CH0_O output is 5 clock cycles.
1: Channel 0 output compare fast enable. The minimum delay from an edge on the
trigger input to activate CH0_O output is 3 clock cycles.
1:0
CH0MS[1:0]
Channel 0 mode selection
This bit-field specifies the direction of the channel and the input signal selection.
This bit-field is writable only when the channel is OFF (CH0EN bit in
TIMERx_CHCTL2 register is reset).
00: Channel 0 is configured as output
01: Channel 0 is configured as input, IC0 is connected to CI0FE0
10: Channel 0 is configured as input, IC0 is connected to CI1FE0
11: Channel 0 is configured as input, IC0 is connected to ITS. This mode is working
only if an internal trigger input is selected through TRGS bits in TIMERx_SMCFG
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register.
Input capture mode:
Bits
Fields
Descriptions
15:8
Reserved
Must be kept at reset value
7:4
CH0CAPFLT[3:0]
Channel 0 input capture filter control
An event counter is used in the digital filter, in which a transition on the output
occurs after N input events. This bit-field specifies the frequency used to sample
CI0 input signal and the length of the digital filter applied to CI0.
0000: Filter disable, fSAMP=fDTS, N=1
0001: fSAMP=fTIMER_CK, N=2
0010: fSAMP= fTIMER_CK, N=4
0011: fSAMP= fTIMER_CK, N=8
0100: fSAMP=fDTS/2, N=6
0101: fSAMP=fDTS/2, N=8
0110: fSAMP=fDTS/4, N=6
0111: fSAMP=fDTS/4, N=8
1000: fSAMP=fDTS/8, N=6
1001: fSAMP=fDTS/8, N=8
1010: fSAMP=fDTS/16, N=5
1011: fSAMP=fDTS/16, N=6
1100: fSAMP=fDTS/16, N=8
1101: fSAMP=fDTS/32, N=5
1110: fSAMP=fDTS/32, N=6
1111: fSAMP=fDTS/32, N=8
3:2
CH0CAPPSC[1:0]
Channel 0 input capture prescaler
This bit-field specifies the ratio of the prescaler on channel 0 input.The prescaler is
reset when CH0EN bit in TIMERx_CHCTL2 register is reset.
00: prescaler disable, capture is done on each channel input edge
01: capture is done every 2 channel input edges
10: capture is done every 4 channel input edges
11: capture is done every 8 channel input edges
1:0
CH0MS[1:0]
Channel 0 mode selection
This bit-field specifies the direction of the channel and the input signal selection.
This bit-field is writable only when the channel is OFF (CH0EN bit in
TIMERx_CHCTL2 register is reset).
00: channel 0 is configured as output
01: channel 0 is configured as input, IC0 is connected to CI0FE0
10: Channel 0 is configured as input, IC0 is connected to CI1FE0
11: channel 0 is configured as input, IC0 is connected to ITS. This mode is
working only if an internal trigger input is selected through TRGS bits in
TIMERx_SMCFG register.
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Channel control register 2 (TIMERx_CHCTL2)
Address offset: 0x20
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
CH0NP
CH0NEN
CH0P
CH0EN
rw
rw
rw
rw
Bits
Fields
Descriptions
15:4
Reserved
Must be kept at reset value
3
CH0NP
Channel 0 complementary output polarity
When channel 0 is configured in output mode, this bit specifies the complementary
output signal polarity.
0: Channel 0 active high
1: Channel 0 active low
This bit cannot be modified when PROT[1:0] bit-filed in TIMERx_CCHP register is
11 or 10.
2
CH0NEN
Channel 0 complementary output enable
When channel 0 is configured in output mode, setting this bit enables the
complementary output in channel 0.
0: Channel 0 complementary output disabled
1: Channel 0 complementary output enabled
1
CH0P
Channel 0 polarity
When channel 0 is configured in input mode, this bit specifies the CI0 signal
polarity. When channel 0 is configured in output mode, this bit specifies the output
signal polarity.
0: Channel 0 active high
1: Channel 0 active low
This bit cannot be modified when PROT[1:0] bit-filed in TIMERx_CCHP register is
11 or 10.
0
CH0EN
Channel 0 enable
When channel 0 is configured in input mode, setting this bit enables CH0_O signal
in active state. When channel 0 is configured in output mode, setting this bit enables
the capture event in channel 0.
0: Channel 0 disabled
1: Channel 0 enabled
Counter register (TIMERx_CNT)
Address offset: 0x24
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Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
CNT[15:0]
rw
Bits
Fields
Descriptions
15:0
CNT[15:0]
This bit-filed indicates the current counter value. Writing to this bit-filed can change
the value of the counter.
Prescaler register (TIMERx_PSC)
Address offset: 0x28
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
PSC[15:0]
rw
Bits
Fields
Descriptions
15:0
PSC[15:0]
Prescaler value of the counter clock
The PSC clock is divided by (PSC+1) to generate the counter clock. The value of
this bit-filed will be loaded to the corresponding shadow register at every update
event.
Counter auto reload register (TIMERx_CAR)
Address offset: 0x2C
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
CAR[15:0]
rw
Bits
Fields
Descriptions
15:0
CAR[15:0]
Counter auto reload value
This bit-filed specifies the auto reload value of the counter.
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Counter repetition register (TIMERx_CREP)
Address offset: 0x30
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
CREP[7:0]
rw
Bits
Fields
Descriptions
15:8
Reserved
Must be kept at reset value.
7:0
CREP[7:0]
Counter repetition value
This bit-filed specifies the update event generation rate. Each time the repetition
counter counting down to zero, an update event is generated. The update rate of
the shadow registers is also affected by this bit-filed when these shadow registers
are enabled.
Channel 0 capture/compare value register (TIMERx_CH0CV)
Address offset: 0x34
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
CH0VAL[15:0]
rw
Bits
Fields
Descriptions
15:0
CH0VAL[15:0]
Capture or compare value of channel 0
When channel 0 is configured in input mode, this bit-filed indicates the counter
value corresponding to the last capture event. And this bit-filed is read-only.
When channel 0 is configured in output mode, this bit-filed contains value to be
compared to the counter. When the corresponding shadow register is enabled, the
shadow register updates every update event.
Channel Complementary Protection register (TIMERx_CCHP)
Address offset: 0x44
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
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POEN
OAEN
BRKP
BRKEN
ROS
IOS
PROT[1:0]
DTCFG[7:0]
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
15
POEN
Primary output enable
This bit s set by software or automatically by hardware depending on the OAEN bit.
It is cleared asynchronously by hardware assoon as the break input is active. When
a channel is configured in output mode, setting this bit enables the channel outputs
(CHx_O and CHx_ON) if the corresponding enable bits (CHxEN, CHxNEN in
TIMERx_CHCTL2 register) have been set.
0: Channel outputs are disabled or forced to idle state.
1: Channel outputs are enabled.
14
OAEN
Output automatic enable
This bit specifies whether the POEN bit can be set automatically by hardware.
0: POEN can be not set by hardware.
1: POEN can be set by hardware automatically at the next update event,if the break
input is notactive.
This bit can be modified only when PROT[1:0] bit-filed in TIMERx_CCHP register is
00.
13
BRKP
Break polarity
This bit specifies the polarity of the BRK input signal.
0: BRK input active low
1: BRK input active high
12
BRKEN
Break enable
This bit can be set to enable the BRK and CCS clock failure event inputs.
0: Break inputs disabled
1: Break inputs enabled
This bit can be modified onlywhen PROT[1:0] bit-filed in TIMERx_CCHP register is
00.
11
ROS
Run mode off-state configure
When POEN bit is set, this bit specifies the output state for the channels which has
a complementary output and has been configured in output mode.
0: When POEN bit is set, the channel output signals (CHx_O/CHx_ON) are disabled
1: When POEN bit is set, he channel output signals (CHx_O/CHx_ON)are enabled,
with relationship to CHxEN/CHxNEN bits in TIMERx_CHCTL2 register
This bit cannot be modified when PROT[1:0] bit-filed in TIMERx_CCHP register is
10 or 11.
10
IOS
Idle mode off-state configure
When POEN bit is reset, this bit specifies the output state for the channels which
has been configured in output mode.
0: When POEN bit is reset, the channel output signals (CHx_O/CHx_ON) are
GD32F1x0 User Manual
349
disabled.
1: When POEN bit is reset, he channel output signals (CHx_O/CHx_ON)are
enabled, with relationship to CHxEN/CHxNEN bits in TIMERx_CHCTL2 register.
This bit cannot be modified when PROT[1:0] bit-filed in TIMERx_CCHP register is
10 or 11.
9:8
PROT[1:0]
Complementary register protect control
This bit-filed specifies the write protection property of registers.
00: protect disable. No write protection.
01: PROT mode 0.The ISOx/ISOxN bits in TIMERx_CTL1 register and the
BRKEN/BRKP/OAEN/DTCFG bits in TIMERx_CCHP register are writing protected.
10: PROT mode 1. In addition of the registers in PROT mode 0, the CHxP/CHxNP
bits in TIMERx_CHCTL2 register (if related channel is configured in output mode)
and the ROS/IOS bits in TIMERx_CCHP register are writing protected.
11: PROT mode 2. In addition of the registers in PROT mode 1, the
CHxCOMCTL/CHxCOMSEN bits in TIMERx_CHCTLx registers (if the related
channel is configured in output) are writing protected.
This bit-field can be written only once after the reset. Once the TIMERx_CCHP
register has been written, this bit-field will be writing protected.
7:0
DTCFG[7:0]
Dead time configure
This bit-field specifies the duration of the dead-time, which is inserted before the
output transitions. The relationship between DTCFG value and the duration of dead-
time is as follow:
DTCFG[7:5]=0xx: duration =DTCFG[7:0]x tDT, tDT=tDTS.
DTCFG[7:5]=10x:duration =(64+DTCFG[5:0])xtDT,tDT=tDTS*2.
DTCFG[7:5]=110: duration =(32+DTCFG[4:0])xtDT, tDT=tDTS*8.
DTCFG[7:5]=111:duration =(32+DTCFG[4:0])xtDT,tDT=tDTS*16.
This bit can be modified only when PROT[1:0] bit-filed in TIMERx_CCHP register is
00.
DMA configuration register (TIMERx_DMACFG)
Address offset: 0x48
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
DMATC[4:0]
Reserved
DMATA[4:0]
rw
rw
Bits
Fields
Descriptions
15:14
Reserved
Must be kept at reset value
12:8
DMATC[4:0]
DMA transfer count
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When register access are done through the TIMERx_DMATB address, this 5-bit bit-
field specifies the number of transfers.
7:5
Reserved
Must be kept at reset value
4:0
DMATA[4:0]
DMA transfer access start address
When register access are done through the TIMERx_DMATB address, this bit-field
specifies the offset of the starting address from the TIMERx_CTL0 register.
DMA Transfer buffer register (TIMERx_DMATB)
Address offset: 0x4C
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
DMATB[15:0]
rw
Bits
Fields
Descriptions
15:0
DMATB[15:0]
DMA transfer
When a read or write operation is assigned to this register, the register located at
the address range (DMATA + burst counter) x 4 from TIMERx_CTL0 will be
accessed.
The burst counter is calculated by hardware, and ranges from 0 to DMATC.
Configuration register (TIMERx_CFG) of GD32F170xx and GD32F190xx
devices
Address offset: 0xFC
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
CCSEL
OUTSEL
rw
rw
Bits
Fields
Descriptions
15:2
Reserved
Must be kept at reset value
1
CCSEL
Write Capture/Compare register selection
This bit-field set and reset by software.
1: If write the Capture/Compare register, the write value is same as the
Capture/Compare value, the write access ignored.
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351
0: No effect
0
OUTSEL
The output value selection.
This bit-field set and reset by software.
1: If POEN and IOS is 0, the output disabled
0: No effect
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10. Infrared ray port (IFRR)
10.1. Introduction
Infrared ray port (IFRR) is used to control infrared light LED, and send out infrared data to
implement infrared ray remote control.
There is no register in this module, which is controlled by TIMER15 and TIMER16. You can
improve the module's output to high current capacity by set the GPIO pin to Fast Mode.
10.2. Main features
The IFRR output is enabled by enabling PB9 pin high current capability(set PB9_HCCE)
The IFRR output signal is decided by TIMER15_CH0 and TIMER16_CH0
To get correct infrared ray signal, TIMER15 should generate low frequence modulation
envelope signal, and TIMER16 should generate high frequence carrier signal
PB9 should provide high current to control LED interface
10.3. Function description
IFRR is a module which could integrate the output of TIMER15 and TIMER16 to generate an
infrared ray signal.
1. The TIMER15’s CH0 is programed to generate the low frequence PWM signal which is
the modulation evalope signal. The TIMER16’s CH0 is programed to generate the high
frquence PWM signal which is the carrier signal. And the channel is needed to enable
before generating these signals.
2. Program the GPIO remap regisger and enable the pin.
3. If you want to get the high current capacity of output, remapping IFRR_OUT to PB9 and
setting the PB9 to Fast Mode by the register in SYS_CFG module are required.
Figure 10-1. IFRR output timechart 1
Note: IFRR_OUT has one APB clock delay from TIMER16_CH0.
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353
Figure 10-2. IFRR output timechart 2
Note: Carrier(TIMER15_CH0)’s duty cycle can be changed, and IFRR_OUT has inverted
relationship with TIMER16_CH0 when TIMER15_CH0 is high.
Figure 10-3. IFRR output timechart 3
Note: IFRR_OUT will keep the integrity of TIMER16_CH0, even if evelope signal
(TIMER15_CH0) is no active.
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11. Watchdog timer (WDGT)
The Watchdog Timer (WDGT) is a hardware timing circuitry that can be used to detect system
failures due to software malfunctions. The GD32F1x0 has two watchdog peripherals, Free
watchdog timer and Window watchdog timer. They offer a combination of a high safety level,
flexibility of use and timing accuracy. Both watchdog peripherals are offered to resolve
malfunctions of software. The Watchdog will generate a reset (or an interrupt in Window
watchdog timer) when the counter reaches a given value.
The Watchdog Timer counter can be stopped while the processor is in the debug mode. The
register write protection function in Free watchdog timer can be enabled to prevent it from
changing the configuration unexpectedly.
11.1. Free watchdog timer (FWDGT)
11.1.1. Introduction
The Free watchdog timer (FWDGT) has independent clock source (IRC40K). There upon the
FWDGT can operate even if the main clock fails. It’s suitable for the situation that requires an
independent environment and lower timing accuracy. The Window watchdog timer (WWDGT)
is suitable for the situation that requires an accurate timing.
In addition, the FWDGT has a configurable window value, if the software reloads the counter
before the counter reaches the window value, a reset will be generated.
11.1.2. Main features
Free-running 12-bit downcounter.
Reset when the downcounter reaches 0, if the watchdog is enabled.
Reset when the downcounter is reloaded outside the window, if watchdog activated.
Independent clock source，FWDGT can operate even if the main clock fails such as in
standby and Deep-sleep modes.
Hardware free watchdog timer bit, automatically start the FWDGT at power on or not
depending on this bit.
FWDGT debug mode congfig bit, the FWDGT continus to work or stoped in debug mode
depends on this bit.
11.1.3. Function description
The free watchdog timer consists of an 8-stage prescaler and a 12-bit down-counter. Refer to
the figure below for the functional blocks of the free watchdog timer module.
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355
Figure 11-1. Free watchdog timer block diagram
The free watchdog timer is enabled by writing the value 0xCCCC in the control register
(FWDGT_CTL), and the counter starts counting down. When the counter reaches the value
0x000, a reset is generated.
Reload the counter by writing the value 0xAAAA in the control register anytime, the reload
value is come from the FWDGT_RLD register. The software prevents the watchdog reset by
reloading the counter before the counter reaches the value 0x000.
By setting the appropriate window in the FWDGT_WND register, the FWDGT can also work
as a Window watchdog timer. A reset will occur if the reload operation is performed while the
counter is greater than the value stored in the window register (FWDGT_WND). The default
value of the FWDGT_WND is 0x0000 0FFF, so if it is not updated, the window option is
disabled. A reload operation is performed in order to reset the downcounter to the
FWDGT_RLD value and the prescaler counter to generate the next reload, as soon as the
window value is changed.
The free watchdog timer can automatically start at power on when the hardware free
watchdog timer bit in the device option bits is set. Then the software should reload the counter
before the counter reaches 0x000.
The FWDGT_PSC register, the FWDGT_RLD register and the FWDGT_WND register are
write protected. Before writing these registers, the software should write the value 0x5555 in
the control register. These registers will be protected again by writing any other value in the
control register. When an update of the prescaler (FWDGT_PSC) or watchdog counter
window value (FWDGT_WND) or the reload value (FWDGT_RLD) is on going, the status bit
in FWDGT_STAT register is set.
If the FWDGT_HOLD bit in DBG module is cleared, the FWDGT continues to work even the
Cortex™-M3 core halted (Debug mode). While the FWDGT stops in Debug mode if the
FWDGT_HOLD bit is set.
IRC40K
Reset
Prescaler
/4/8…256
12-Bit Down
Counter
Reload
register
Control
register
Status: PUD
Status: RUD
Reload
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Table 11-1. Min/max FWDGT timeout period at 40 kHz (IRC40K)
Prescaler
divider
PSC[2:0]
bits
Min timeout (ms)
RL[11:0]=
0x000
Max timeout (ms)
RL[11:0]=
0xFFF
1/4
000
0.1
409.6
1/8
001
0.2
819.2
1/16
010
0.4
1638.4
1/32
011
0.8
3276.8
1/64
100
1.6
6553.6
1/128
101
3.2
13107.2
1/256
110 or 111
6.4
26214.4
The FWDGT timeout can be more accurately by calibrating the IRC40K.
11.1.4. FWDGT registers
Control register (FWDGT_CTL)
Address offset: 0x00
Reset value: 0x0000 0000
This register can be accessed by half-word (16-bit) or word (32-bit) access
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
CMD[15:0]
wo
Bits
Fields
Descriptions
31:16
Reserved
Must be kept at reset value
15:0
CMD[15:0]
Write only. These bits have different fuctions when writing different values
0x5555: Disable the FWDGT_PSC, FWDGT_RLD and FWDGT_WND write
protection
0xCCCC: Start the free watchdog timer counter. When the counter reduces to 0, the
free watchdog timer generates a reset
0xAAAA: Reload the counter
Prescaler register (FWDGT_PSC)
Address offset: 0x04
Reset value: 0x0000 0000
This register can be accessed by half-word (16-bit) or word (32-bit) access
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31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
PSC[2:0]
rw
Bits
Fields
Descriptions
31:3
Reserved
Must be kept at reset value
2:0
PSC[2:0]
Free watchdog timer prescaler selection. Write 0x5555 in the FWDGT_CTL register
before writing these bits. When a write operation to this register ongoing, the PUD bit
in the FWDGT_STAT register is set and the value read from this register is invalid.
000: 1/4 001: 1/8 010: 1/16
011: 1/32 100: 1/64 101: 1/128
110: 1/256 111: 1/256
If several prescaler values are used by the application, it is mandatory to wait until
PUD bit is reset before changing the prescaler value. However, after updating the
prescaler value it is not necessary to wait until PUD is reset before continuing code
execution except in case of low-power mode entry.
Reload register (FWDGT_RLD)
Address offset: 0x08
Reset value: 0x0000 0FFF
This register can be accessed by half-word (16-bit) or word (32-bit) access
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
RLD [11:0]
rw
Bits
Fields
Descriptions
31:12
Reserved
Must be kept at reset value
11:0
RLD[11:0]
Free watchdog timer counter reload value. Write 0xAAAA in the FWDGT_CTL register
will reload the FWDGT conter.
These bits are write-protected. Write 0X5555 in the FWDGT_CTL register before writing
these bits. When a write operation to this register ongoing, the RUD bit in the
FWDGT_STAT register is set and the value read from this register is invalid.
If several reload values are used by the application, it is mandatory to wait until RUD
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358
bit is reset before changing the reload value. However, after updating the reload value
it is not necessary to wait until RUD is reset before continuing code execution except
in case of low-power mode entry.
Status register (FWDGT_STAT)
Address offset: 0x0C
Reset value: 0x0000 0000
This register can be accessed by half-word (16-bit) or word (32-bit) access
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
WUD
RUD
PUD
ro
ro
ro
Bits
Fields
Descriptions
31:2
Reserved
Must be kept at reset value
2
WUD
Watchdog counter window value update
When a write operation to FWDGT_WND register ongoing, this bit is set and the value
read from FWDGT_WND register is invalid.
1
RUD
Free watchdog timer counter reload value update
When a write operation to FWDGT_RLD register ongoing, this bit is set and the value
read from FWDGT_RLD register is invalid.
0
PUD
Free watchdog timer prescaler value update
When a write operation to FWDGT_PSC register ongoing, this bit is set and the value
read from FWDGT_PSC register is invalid.
Window register (FWDGT_WND)
Address offset: 0x10
Reset value: 0x0000 0000
This register can be accessed by half-word (16-bit) or word (32-bit) access
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
WND[11:0]
r
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359
Bits
Fields
Descriptions
31:12
Reserved
Must be kept at reset value
11:0
WND[11:0]
Watchdog counter window value. These bits are used to contain the high limit of the
window value to be compared to the downcounter. A reset will occur if the reload
operation is performed while the counter is greater than the value stored in this register.
The WUD bit in the FWDGT_STAT register must be reset in order to be able to change
the reload value.
These bits are write protected. Write 5555h in the FWDGT_CTL register before writing
these bits.
If several window values are used by the application, it is mandatory to wait until WUD
bit is reset before changing the window value. However, after updating the window
value it is not necessary to wait until WUD is reset before continuing code execution
except in case of low-power mode entry.
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11.2. Window watchdog timer (WWDGT)
11.2.1. Introduction
The Window watchdog timer (WWDGT) is used to detect system failures due to software
malfunctions.After the Window watchdog timer start, the 7-bit downcounter reduce
progressively. The watchdog causes a reset when the counter reached 0x3F (the CNT[6] bit
becomes cleared). The watchdog also cause a reset if the counter is refreshed before the
counter reached the window register value. So the software should refresh the counter in a
limited window. The Window watchdog timer has an early wakeup status flag when the
counter reaches 0x40. Interrupt occurs if it is enabled
The Window watchdog timer (WWDGT) clock is prescaled from the APB1 clock.
11.2.2. Main features
Programmable free-running 7-bit downcounter
Conditional reset, when WWDGT is enabled :
- Reset when the counter reached 0x3F
- The counter is refreshed when the value of the counter is greater than the window
register value
Early wakeup interrupt (EWI): if the watchdog is started and the interrupt is enabled, the
interrupt occurred when the counter reached 0x40
WWDGT debug mode, the WWDGT can stop or continue to work in debug mode.
11.2.3. Function description
If the Window watchdog timer is enable (set the WDGTEN bit in the WWDGT_CTL), the
watchdog cause a reset when the counter reached 0x3F (the CNT[6] bit becomes cleared),
or when the counter is refreshed before the counter reached the window register value.
Figure 11-2. Window watchdog timer block diagram
Reset
Write WWDGT_CTL
CNT>WIN
CNT[6]=0
Reset
PCLK1/4096
Prescaler
/1/2/4/8
7-Bit Down Counter
CNT
Window WIN
WDGTEN
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361
The watchdog is always disabled after power on reset. The software starts the watchdog by
setting the WDGTEN bit in the WWDGT_CTL register. Whenever Window watchdog timer is
enabled, the counter counts down all the time, the configured value of the counter should be
greater than 0x3F, it implies that the CNT[6] bit should be set. The CNT[5:0] determine the
maximum time interval of two reloading. The countdown speed depends on the APB1 clock
and the prescaler (PSC[1:0] bits in the WWDGT_CFG register).
The WIN[6:0] bits in the configuration register (WWDGT_CFG) specifies the window value.
The software can prevent the reset event by reloading the downcounter when counter value
is less than the window value and greater than 0x3F, otherwise the watchdog causes a reset.
The Early Wakeup Interrupt (EWI) is enabled by setting the EWIE bit in the WWDGT_CFG
register, and the interrupt will occur when the counter reaches 0x40. The software can do
something such as communications or data logging in the interrupt service routine (ISR) in
order to analyse the reason of software malfunctions or save the important data before
resetting the device. Moreover the software can reload the counter in ISR to manage a
software system check and so on. In this case, the WWDGT will never generate a WWDGT
reset but used for other things.
The EWI interrupt is cleared by writing '0' to the EWIF bit in the WWDGT_STAT register.
Figure 11-3. Window watchdog timer timing diagram
Calculate the WWDGT timeout by using the formula below.
tWWDGT = tPCLK1 × 4096 × 2PSC × (CNT[5:0] + 1) (ms)
where:
tWWDGT: WWDGT timeout
tPCLK1: APB1 clock period measured in ms
Refer to the table below for the minimum and maximum values of the tWWDG.
Write WWDGT_CTL when CNT>WIN cause reset
cause a reset
CNT[6]=0 cause a reset
0x7F Start
CNT[6:0]
0x3F
WIN
Write CNT
Start
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Table 11-2. Min-max timeout value at 36 MHz (fPCLK1)
Prescaler
divider
PSC[1:0]
Min timeout value
CNT[6:0] =0x40
Max timeout value
CNT[6:0]=0x7F
1/1
00
113 μs
7.28 ms
1/2
01
227 μs
14.56 ms
1/4
10
455 μs
29.12 ms
1/8
11
910 μs
58.25 ms
If the WWDGT_HOLD bit in DBG module is cleared, the WWDGT continues to work even the
Cortex™-M3 core halted (Debug mode). While the WWDGT_HOLD bit is set, the WWDGT
stops in Debug mode.
11.2.4. WWDGT registers
Control register (WWDGT_CTL)
Address offset: 0x00
Reset value: 0x0000 007F
This register can be accessed by half-word (16-bit) or word (32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
WDGTEN
CNT[6:0]
rs
rw
Bits
Fields
Descriptions
31:8
Reserved
Must be kept at reset value.
7
WDGTEN
Start the Window watchdog timer. Cleared by a hardware reset. Writing 0 has no effect.
0: Window watchdog timer disabled
1: Window watchdog timer enabled
6:0
CNT[6:0]
The value of the watchdog timer counter. A reset will occur when the value of this
counter decreases from 0x40 to 0x3F. Writing this counter when the value of this
counter is greater than the window value also cause a reset.
Configuration register (WWDGT_CFG)
Address offset: 0x04
Reset value: 0x0000 007F
This register can be accessed by half-word (16-bit) or word (32-bit)
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31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
EWIE
PSC [1:0]
WIN[6:0]
rs
rw
rw
Bits
Fields
Descriptions
31:10
Reserved
Must be kept at reset value.
9
EWIE
Early wakeup interrupt enable. An interrupt will occur when the counter reaches 0x40 if
the bit is set. It’s could be cleared by a hardware reset or software clock reset (refer to
4.3.5. APB1 reset register ) . A write of 0 has no effect.
8:7
PSC[1:0]
Prescaler. The time base of the watchdog counter
00: PCLK1 / 4096 / 1
01: PCLK1 / 4096 / 2
10: PCLK1 / 4096 / 4
11: PCLK1 / 4096 / 8
6:0
WIN[6:0]
The Window value. A reset will occur if the watchdog counter (CNT bits in
WWDGT_CTL) is written when the value of the watchdog counter is greater than the
Window value.
Status register (WWDGT_STAT)
Address offset: 0x08
Reset value: 0x0000 0000
This register can be accessed by half-word (16-bit) or word (32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
EWIF
rw
Bits
Fields
Descriptions
31:1
Reserved
Must be kept at reset value.
0
EWIF
Early wakeup interrupt flag. When the counter has reached 0x40, this bit is set by
hardware even the interrupt is not enabled (EWIE in WWDGT_CFG is cleared). This bit
is cleared by writing 0 . There is no effect when writing 1 to it.
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12. Analog to digital converter (ADC)
12.1. Introduction
The 12 bit ADC is an analog-to-digital converter using successive approximation approach. It
has 19 multiplexed channels which are used to measure the signals from 16 external and 3
internal signal sources. Analog watchdog allows the application to detect whether the input
voltage exceeds the user's set of high and low threshold. The A/D conversion of each channel
can be performed in single, continuous, scan, or discontinuous mode. The result of the ADC
will be stored in a 16 bit data register in left or right aligned manner.
12.2. Main features
For GD32F130xx and GD32F150xx devices:
12-bit resolution
ADC conversion time: 1.0 us (1MS/s)
Dual clock domain architecture (APB clock and ADC clock)
Self-calibration time: 83 ADC clock periods
Programmable sampling time
Configurable data alignment in data registers
DMA request for regular data transfer
Analog input channels: 16 external analog inputs, 1 channel for internal temperature
sensor (VSENSE), 1 channel for internal reference voltage (VREFINT), 1 channel for
monitoring external VBAT power supply pin
Conversion modes: single, scan, continuous and discontinuous
Analog watchdog
ADC supply requirements: 2.6V to 3.6V
ADC input range: VSSA ≤VIN ≤VDDA
Interrupt generation at the end of regular and inserted group conversions, and in case of
analog watchdog
External trigger on regular and inserted channels
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For GD32F170xx and GD32F190xx devices:
High performance
12-bit, 10-bit, 8-bit, or 6-bit configurable resolution
ADC conversion time: 0.5μs for 12-bit resolution (2MS/s), about 0.43μs conversion
time for 10-bit resolution, about 0.286μs for 6-bit resolution. Faster conversion time
can be obtained by lowering the resolution
Self-calibration time: 84 ADC clock cycles
Programmable sampling time
Configurable data alignment in data registers
DMA request for regular data transfer
Dual clock domain architecture (APB clock and ADC clock)
Analog input channels
16 external analog inputs
1 channel for internal temperature sensor (VSENSE)
1 channel for internal reference voltage (VREFINT)
1 channel for monitoring external VBAT power supply pin
Start of the conversion can be initiated:
By software
By hardware triggers with configurable polarity (internal timer events from
TIMER0,TIMER1, TIMER2 and TIMER14)
External trigger on regular and inserted channels
Conversion modes:
Can convert a single channel or can scan a sequence of channels.
Single mode converts selected inputs once per trigger
Continuous mode converts selected inputs continuously
Discontinuous mode
Interrupt generation at the end of regular and inserted group conversions, and in case of
analog watchdog events
Analog watchdog
ADC supply requirements: from 3V to 5.5V, and typical power supply voltage is 5V.
Oversampling
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16-bit data register
Oversampling ratio adjustable from 2 to 256x
Programmable data shift up to 8-bits
ADC input range: VSSA ≤VIN ≤VDDA
12.3. Function description
Figure 12-1 and Figure 12-2 show the ADC block diagram.
Figure 12-1. ADC module block diagram of GD32F130xx and GD32F150xx devices
ADC_IN0
ADC_IN1
· ·
·
ADC_IN15
GPIO
VSENSE
VREF
VDDA
VSSA
Inserted data registers
（16 bits x 4）
Regular data registers
（16 bits）
Regular
channels Inserted
channels
Channel Mangement
Trig select
EXTI_11
TIMER0_CH0
TIMER0_CH1
TIMER0_CH2
TIMER1_CH1
TIMER2_TRGO
TIMER14_CH0
Trig select
EXTI_15
TIMER0_TRGO
TIMER0_CH3
TIMER1_TRGO
TIMER1_CH0
TIMER2_CH3
TIMER14_TRGO
Analog
watchdog
A
P
B
B
U
S
EOC
EOIC
watchdog
event
Interrupt
generator
ADC
Interrupt
Analog block
SWRCST
SWICST
VBAT/2
SAR ADC
ADC_CLB self calibration
DMA request
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Figure 12-2. ADC module block diagram of GD32F170xx and GD32F190xx devices
ADC_IN0
ADC_IN1
· · ·
ADC_IN15
GPIO
Channel selector
VBAT/2
VREF
VDDA
VSSA
6~12-
bit
Inserted data registers
（16 bits x 4）
Regular data registers
（16 bits）
Regular
channels Inserted
channels
Channel Mangement
Trig select
EXTI_11
TIMER0_CH0
TIMER0_CH1
TIMER0_CH2
TIMER1_CH1
TIMER2_TRGO
TIMER14_CH0
Trig select
EXTI_15
TIMER0_TRGO
TIMER0_CH3
TIMER1_TRGO
TIMER1_CH0
TIMER2_CH3
TIMER14_TRGO
Analog
watchdog
A
P
B
B
U
S
EOC
EOIC
watchdog
event
Interrupt
generator
ADC
Interrupt
SWRCST
SWICST
SAR ADC
ADC_CLB
self calibration
ADC_DRES[1:0]
12, 10, 8, 6 bits
Over
sampler
OVSS[3:0]
OVSR[2:0]
OVSE
TOVS
VSENSE
DMA request
Table 12-2 and Table 12-3 give the ADC internal signals and pins description.
Table 12-1. ADC internal signals
Internal signal name
Signal type
Description
VSENSE
Input
Internal temperature sensor output voltage
VREFINT
Input
Internal voltage reference output voltage
VBAT/2
Input
VBAT pin input voltage divided by 2
Table 12-2. ADC pins definition of GD32F130xx and GD32F150xx devices
Name
Signal type
Remarks
VDDA(1)
Input, analog supply
Analog power supply equal to VDD and
2.6 V ≤VDDA≤ 3.6 V
VSSA(1)
Input, analog supply
ground
Ground for analog power supply equal to
VSS
ADCx_IN[15:0]
Analog signals
Up to 16 analog channels
Table 12-3. ADC pins definition of GD32F170xx and GD32F190xx devices
Name
Signal type
Remarks
VDDA(1)
Input, analog supply
Analog power supply equal to VDD and 3 V
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≤ VDDA ≤ 5.5 V
VSSA(1)
Input, analog supply
ground
Ground for analog power supply equal to
VSS
ADCx_IN[15:0]
Analog signals
Up to 16 analog channels
1. VDDA and VSSA have to be connected to VDD and VSS, respectively.
12.3.1. Calibration (ADC_CLB)
The ADC has a calibration feature. The application must not use the ADC during calibration
and must wait until it is completed. Calibration should be performed before starting A/D
conversion. For GD32F130xx and GD32F150xx devices, the calibration needs 83 clock
periods to remove the comparator offset error and capacitor mismatch error which may vary
from chip to chip due to process variation. But it needs 84 clock periods for GD32F170xx and
GD32F190xx devices.
The calibration is initiated by software by setting bit ADC_CLB=1. ADC_CLB bit stays at 1
during all the calibration sequence. It is then cleared by hardware as soon as the calibration
completes.
When the ADC’s operating conditions change (VDDA changes are the main contributor to ADC
offset variations and temperature changes are the secondary contributor), it is recommended
to re-run a calibration cycle.
The internal analog calibration can be reset by setting the RSTCLB bit in ADC_CTL1 register.
Calibration software procedure:
1. Ensure that ADCON=1
2. Set RSTCLB (optional)
3. Set CLB=1
4. Wait until CLB =0
12.3.2. Dual clock domain architecture
The ADC sub-module, with exception of the APB interface block, is feed by an ADC clock,
which can be asynchronous and independent from the APB clock.
Application can reduce PLCK frequency for low power operation while still keeping optimum
ADC performance.
Refer to RCU Section 4.2.1 for more information on generating this clock source.
12.3.3. Regular and inserted channel groups
The ADC supports 19 multiplexed channels and organizes the conversion results into two
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groups: a regular channel group and an inserted channel group.
In the regular group, a sequence of up to 16 conversions can be organized in a specific
sequence. The ADC_RSQ0~ADC_RSQ2 registers specify the selected channels of the
regular group. The RL[3:0] bits in the ADC_RSQ0 register specify the total conversion
sequence length.
In the inserted group, a sequence of up to 4 conversions can be organized in a specific
sequence. The ADC_ISQ register specifies the selected channels of the inserted group. The
IL[1:0] bits in the ADC_ISQ register specify the total conversion sequence length.
12.3.4. Conversion modes
Single conversion mode
In the single conversion mode, the ADC performs conversion on the channels with a specific
sequence specified in the ADC_RSQ0~ADC_RSQ2 registers or ADC_ISQ register. Once the
ADCON is set high, the ADC samples and converts a single channel in the regular or inserted
group, when the corresponding software trigger or external trigger is active. After conversion
of the single channel, the conversion data will be stored in the ADC_RDATA or ADC_IDATAx
register. The EOC or EOIC will be set. An interrupt will be generated if the EOCIE or EOICIE
bit is set.
Figure 12-3. Single conversion mode
CH2CH1CH5CH7CH11 CH16 CH2CH1· · ·
Inserted
trigger
EOC
One circle of regular group, RL=6
CH9CH10 CH8CH6CH9CH10 · · ·
EOIC
One circle of inserted group, IL=4
Regular
trigger
Sample
Convert
Continuous conversion mode
The continuous conversion mode will be enabled when CTN bit in the ADC_CTL1 register is
set. In this mode, the ADC performs conversion on the channels with a specific sequence
specified in the ADC_RSQ0~ADC_RSQ2 registers or ADC_ISQ register. Once the ADCON
is set high, the ADC samples and converts specified channels one by one in the regular or
inserted group, when the corresponding software trigger or external trigger is active. The
conversion data will be stored in the ADC_RDATA or ADC_IDATAx register. If scan mode is
disabled, the EOC or EOIC will be set after conversion of every channel. If scan mode is
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enabled, the EOC or EOIC will be set after every circle of the regular or inserted channel
group. An interrupt will be generated if the EOCIE or EOICIE bit is set.
Figure 12-4. Continuous conversion mode, scan disable
CH2CH1CH5CH7CH11 CH16 CH2CH1· · ·
Inserted
trigger
EOC
One circle of regular group, RL=8
CH9CH10 CH8CH6CH9CH10 · · ·
EOIC
One circle of inserted group, IL=4
Regular
trigger
Sample
Convert
CH12 CH17 CH5
Figure 12-5. Continuous conversion mode, scan enable
CH2 CH1 CH5 CH7 CH11 CH2 CH1 · · ·
Inserted
trigger
EORC
One circle of regular group, RL=5
CH10 CH8 CH6 CH10 · · ·
EOIC
One circle of inserted group, IL=3
Regular
trigger
Sample
Convert
CH5 CH7 CH11 CH2
CH8 CH6 CH10
Scan conversion mode
The scan conversion mode will be enabled when SM bit in the ADC_CTL0 register is set. In
this mode, the ADC performs conversion on the channels with a specific sequence specified
in the ADC_RSQ0~ADC_RSQ2 registers or ADC_ISQ register. Once the ADCON is set high,
the ADC samples and converts specified channels one by one in the regular or inserted group
till the end of the regular or inserted group, when the corresponding software trigger or
external trigger is active. The conversion data will be stored in the ADC_RDATA or
ADC_IDATAx register. After conversion of the regular or inserted channel group, the EOC or
EOIC will be set. An interrupt will be generated if the EOCIE or EOICIE bit is set. The DMA
bit in ADC_CTL1 register must be set in scan mode.
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Figure 12-6. Scan conversion mode
CH2CH1CH5CH7CH11 CH16 CH2CH1· · ·
Inserted
trigger
EOC
One circle of regular group, RL=8
CH9CH10 CH8CH6CH9CH10 · · ·
EOIC
One circle of inserted group, IL=4
Regular
trigger
Sample
Convert
CH12 CH17
Discontinuous mode
For regular channel group, the discontinuous conversion mode will be enabled when DISRC
bit in the ADC_CTL0 register is set. In this mode, the ADC performs a short sequence of n
conversions (n<=8) which is a part of the sequence of conversions selected in the
ADC_RSQ0~ADC_RSQ2 registers. The value of n is defined by the DISNUM[2:0] bits in the
ADC_CTL0 register. When the corresponding software trigger or external trigger is active, the
ADC samples and coverts the next n channels selected in the ADC_RSQ0~ADC_RSQ2
registers until all the channels in the regular sequence are done. The EOC will be set after
every circle of the regular channel group. An interrupt will be generated if the EOCIE bit is set.
For inserted channel group, the discontinuous conversion mode will be enabled when DISIC
bit in the ADC_CTL0 register is set. In this mode, the ADC performs one conversion which is
a part of the sequence of conversions selected in the ADC_ISQ register. When the
corresponding software trigger or external trigger is active, the ADC samples and coverts the
next channel selected in the ADC_ISQ register until all the channels in the inserted sequence
are done. The EOIC will be set after every circle of the inserted channel group. An interrupt
will be generated if the EOICIE bit is set.
The regular and inserted groups cannot both work in discontinuous conversion mode. Only
for one group conversion can be set in discontinuous conversion mode.
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Figure 12-7. Discontinuous conversion mode
CH2CH1CH5CH7CH11 CH16 CH2CH1· · ·
Inserted
trigger
EOC
One circle of regular group, RL=8, DISNUM=3'b010
CH9CH10 CH8CH9CH10 · · ·
EOIC
One circle of inserted group, IL=3
Regular
trigger
Sample
Convert
CH12 CH17 CH5
12.3.5. Analog watchdog
The analog watchdog is enabled when the RWDEN and IWDEN bits in the ADC_CTL0
register are set for regular and inserted channel groups respectively. When the analog voltage
converted by the ADC is below a low threshold or above a high threshold, the WDE bit in
ADC_STAT register will be set. An interrupt will be generated if the WDEIE bit is set. The
ADC_WDHT and ADC_WLT registers are used to specify the high and low threshold. The
comparison is done before the alignment, so the threshold value is independent of the
alignment, which is specified by the DAL bit in the ADC_CTL1 register. One or more channels
to be monitored by the analog watchdog are selected by the RWDEN, IWDEN, WDSC and
WDCHSEL[4:0] bits in ADC_CTL0 register.
12.3.6. Inserted channel management
Auto-insertion
The inserted group channels are automatically converted after the regular group channels
when the ICA bit in ADC_CTL0 register is set. In this mode, external trigger on inserted
channels cannot be enabled. A sequence of up to 20 conversions programmed in the
ADC_RSQ0~ADC_RSQ2 and ADC_ISQ registers can be used to convert in this mode. In
addition to the ICA bit, if the CTN bit is also set, regular channels followed by inserted
channels are continuously converted.
The auto insertion mode cannot be enabled when the discontinuous conversion mode is set.
Triggered insertion
If the ICA bit is cleared and SM bit is set, the triggered insertion occurs if a software or external
trigger occurs during the regular group channel conversion. In this situation, the ADC abort
from the current conversion and start the conversion of inserted channel sequence in scan
mode. After the inserted channel group is done, the regular group channel conversion is
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resumed from the last aborted conversion.
12.3.7. Data alignment
The alignment of data stored after conversion can be specified by DAL bit in the ADC_CTL1
register.
After decreased by the user-defined offset written in the ADC_IOFFx registers, the inserted
group data value may be a negative value. The sign value is extended.
Figure 12-8. Data alignment of 12-bit resolution
Sign Sign Sign Sign D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
0 0 0 0 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
Regular group data
Inserted group data
0 0 0Sign D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
0 0 0 0D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
Regular group data
Inserted group data
DAL=0
DAL=1
12.3.8. Programmable sample time
The number of ADC_CLK cycles which is used to sample the input voltage can be specified
by the SPTn[2:0] bits in the ADC_SAMPT0 and ADC_SAMPT1 registers. A different sample
time can be specified for each channel. Take the 12-bit resolution as an example, its total
conversion time is “sampling time + 12.5” ADC_CLK cycles.
12.3.9. External trigger
When the ETERC or ETEIC bit in ADC_CTL1 register is set, conversion of regular or inserted
group can be triggered by a rising edge of external trigger input. The ETSRC[2:0] and
ETSIC[2:0] control bits are used to specify which out of 8 possible events can trigger
conversion for the regular and inserted groups.
Table 12-4. External trigger for regular channels of ADC
ETSRC[2:0]
Trigger Source
Trigger Type
000
TIMER0_CH0
Internal on-chip signal
001
TIMER0_CH1
010
TIMER0_CH2
011
TIMER1_CH1
100
TIMER2_TRGO
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ETSRC[2:0]
Trigger Source
Trigger Type
101
TIMER14_CH0
110
EXTI_11
External signal
111
SWRCST
Software trigger
Table 12-5. External trigger for inserted channels of ADC
ETSIC[2:0]
Trigger Source
Trigger Type
000
TIMER0_TRGO
Internal on-chip signal
001
TIMER0_CH3
010
TIMER1_TRGO
011
TIMER1_CH0
100
TIMER2_CH3
101
TIMER14_TRGO
110
EXTI_15
External signal
111
SWICST
Software trigger
12.3.10. DMA request
The DMA request is used to transfer data of regular group for conversion of more than one
channel. The ADC generates a DMA request at the end of conversion of a regular channel.
When this request is received, the DMA will transfer the converted data from the ADC_RDATA
register to the destination location which is specified by the user.
12.3.11. Temperature sensor and internal reference voltage VREF
When the TSVREN bit in ADC_CTL1 register is set, the temperature sensor channel
(ADC_IN16) and VREF channel (ADC_IN17) is enabled. The temperature sensor can be used
to measure the ambient temperature of the device. The sensor output voltage can be
converted into a digital value by ADC. The sampling time for the temperature sensor is
recommended to be set to 17.1µs. When this sensor is not in use, it can be put in power down
mode by resetting the TSVREN bit.
The output voltage of the temperature sensor changes linearly with temperature. Because
there is an offset, which is up to 45°C and varies from chip to chip due to process variation,
on this line, the internal temperature sensor is more suited for applications that detect
temperature variations instead of absolute temperatures. When it is used to detect accurate
temperature, an external temperature sensor part should be used.
The internal voltage reference (VREF) provides a stable (bandgap) voltage output for the ADC
and Comparators. VREF is internally connected to the ADC_IN17 input channel.
To use the temperature sensor:
1. Configure the conversion sequence (ADC_IN16) and the sampling time (17.1μs) for the
channel.
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2. Enable the temperature sensor by setting the TSVREN bit in the ADC control register 1
(ADC_CTL1).
3. Start the ADC conversion by setting the ADCON bit (or by external trigger).
4. Read the resulting temperature data (Vtemperature) in the ADC data register, and get the
temperature using the following formula:
Temperature (°C) = {(V30 – Vtemperature (digit)) / Avg_Slope} + 30.
V30 : Vtemperature value at 30°C ,the typical value is 1.43 V.
Avg_Slope : Average Slope for curve between Temperature vs. Vtemperature, the typical
value is 4.3 mV/°C.
12.3.12. Battery voltage monitoring
The VBAT channel can be used to measure the backup battery voltage on the VBAT pin. When
the VBATEN bit in ADC_CTL1 register is set, VBAT channel (ADC_IN18) is enabled and a
bridge divider by 2 integrated on the VBAT pin is also enabled automatically with it. As VBAT
may be higher than VDDA, this bridge is used to ensure the ADC correct operation. And it
connect VBAT/2 to the ADC_IN18 input channel. So, the converted digital value is VBAT/2. In
order to prevent unnecessary battery energy consumption, it is recommended that the bridge
will be enabled only when it is required.
12.3.13. ADC interrupts
An interrupt can be produced at the end of conversion for regular and inserted groups and
when the analog watchdog status bit is set. The independent interrupt enable bits is used to
set the ADC interrupt flexibly.
12.3.14. Programmable resolution (RES) - fast conversion mode for GD32F170xx
and GD32F190xx devices
It is possible to obtain faster conversion time (tADC) by reducing the ADC resolution.
The resolution can be configured to be either 12, 10, 8, or 6 bits by programming the
DRES[1:0] bits in the ADC_CTL0 register. Lower resolution allows faster conversion time for
applications where high data precision is not required.
The DRES[1:0] bits must only be changed when the ADCON bit is reset.
The result of the conversion is always 12 bits wide and any unused LSB bits are read as
zeroes.
Lower resolution reduces the conversion time needed for the successive approximation steps
as shown in Table 12-6.
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Table 12-6. tSAR timings depending on resolution
DRES[1:0]
bits
tSAR (ADC
clock
cycles)
tSAR (ns) at
fADC=28MHz
tSMPL (ADC
clock
cycles)
tADC (ADC
clock
cycles)
tADC(ns) at
fADC=28MHz
12
12.5
446ns
1.5
14
500ns
10
10.5
375ns
1.5
12
429ns
8
8.5
304ns
1.5
10
357ns
6
6.5
232ns
1.5
8
286ns
12.3.15. Oversampling for GD32F170xx and GD32F190xx devices
The oversampling unit, which is enabled by OVSEN bit in the ADC_OVSAMPCTL register,
provides higher data resolution at the cost of lower output data rate.
The oversampling unit performs data preprocessing to offload the CPU. It can handle multiple
conversions and average them into a single data with increased data width, up to 16-bit.
It provides a result with the following form, where N and M can be adjusted:
 
 


It allows to perform by hardware the following functions: averaging, data rate reduction, SNR
improvement, basic filtering.
The oversampling ratio N is defined using the OVSR[2:0] bits in the ADC_OVSAMPCTL
register. It can range from 2x to 256x. The division coefficient M consists of a right bit shift up
to 8 bits. It is configured through the OVSS[3:0] bits in the ADC_OVSAMPCTL register.
The summation unit can yield a result up to 20 bits (256 x 12-bit), which is first shifted right.
The upper bits of the result are then truncated, keeping only the 16 least significant bits
rounded to the nearest value using the least significant bits left apart by the shifting, before
being finally transferred into the data register.
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Figure 12-9. 20-bit to 16-bit result truncation
Raw 20-bit data
19 15 11 7 3 0
15 11 7 3 0
Shifting
Truncation and
rounding
Note: If the intermediate result after the shifting exceeds 16 bits, the upper bits of the result
are simply truncated.
The Figure 12-10 shows a numerical example of the processing, from a raw 20-bit
accumulated data to the final 16-bit result.
Figure 12-10. Numerical example with 5-bits shift and rounding
2 A C D 6Raw 20-bit data
19 15 11 7 3 0
1566
15 11 7 3 0
Final result after 5-bit shift
and rounding to nearest
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The Table 12-7 below gives the data format for the various N and M combination, for a raw
conversion data equal to 0xFFF.
Table 12-7. Maximum output results vs N and M. Grayed values indicates truncation
Over
sa
mplin
g
ratio
Max
Raw
data
No-
shift
OVSS
=
0000
1-bit
shift
OVSS
=
0001
2-bit
shift
OVSS
=
0010
3-bit
shift
OVSS
=
0011
4-bit
shift
OVSS
=
0100
5-bit
shift
OVSS
=
0101
6-bit
shift
OVSS
=
0110
7-bit
shift
OVSS
=
0111
8-bit
shift
OVS
S=
1000
2x
0x1FF
E
0x1F
FE
0x0F
FF
0x080
0
0x040
0
0x020
0
0x010
0
0x008
0
0x004
0
0x002
0
4x
0x3FF
C
0x3F
FC
0x1F
FE
0x0F
FF
0x080
0
0x040
0
0x020
0
0x010
0
0x008
0
0x004
0
8x
0x7FF
8
0x7F
F8
0x3F
FC
0x1F
FE
0x0F
FF
0x080
0
0x040
0
0x020
0
0x010
0
0x008
0
16x
0xFFF
0
0xFF
F0
0x7F
F8
0x3F
FC
0x1F
FE
0x0F
FF
0x080
0
0x040
0
0x020
0
0x010
0
32x
0x1FF
E0
0xFF
E0
0xFF
F0
0x7F
F8
0x3F
FC
0x1F
FE
0x0F
FF
0x080
0
0x040
0
0x020
0
64x
0x3FF
C0
0xFF
C0
0xFF
E0
0xFF
F0
0x7F
F8
0x3F
FC
0x1F
FE
0x0F
FF
0x080
0
0x040
0
128x
0x7FF
80
0xFF
80
0xFF
C0
0xFF
E0
0xFF
F0
0x7F
F8
0x3F
FC
0x1F
FE
0x0F
FF
0x080
0
256x
0xFFF
00
0xFF
00
0xFF
80
0xFF
C0
0xFF
E0
0xFF
F0
0x7F
F8
0x3F
FC
0x1F
FE
0x0F
FF
The conversion time in oversampling mode do not change compared to standard conversion
mode: the sampling time is maintained equal during the whole oversampling sequence. New
data are provided every N conversion, with an equivalent delay equal to N x tADC = N x (tSMPL
+ tSAR).
Oversampling work with ADC modes
Most of the ADC work modes are available when oversampling is enabled.
Regular or inserted channels
ADC started by softeware or external triggers
Single or scan, continuous or discontinuous conversion modes
Programmable sample time
Analog watchdog
The oversampling configuration can only be changed when ADCON is reset. Make sure
configuring the oversampling before seting ADCON to 1.
GD32F1x0 User Manual
379
12.4. ADC registers
12.4.1. Status register (ADC_STAT)
Address offset: 0x00
Reset value: 0x0000 0000
This register has to be accessed by word (32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
STRC
STIC
EOIC
EOC
WDE
rc_w0
rc_w0
rc_w0
rc_w0
rc_w0
Bits
Fields
Descriptions
31:5
Reserved
Must be kept at reset value
4
STRC
Start flag of regular channel group
0: No regular channel group started
1: Regular channel group started
Set by hardware when regular channel conversion starts.
Cleared by software writing 0 to it.
3
STIC
Start flag of inserted channel group
0: No inserted channel group started
1: Inserted channel group started
Set by hardware when inserted channel group conversion starts.
Cleared by software writing 0 to it.
2
EOIC
End of inserted group conversion flag
0: No end of inserted group conversion
1: End of inserted group conversion
Set by hardware at the end of all inserted group channel conversion.
Cleared by software writing 0 to it.
1
EOC
End of group conversion flag
0: No end of group conversion
1: End of group conversion
Set by hardware at the end of a regular or inserted group channel conversion.
Cleared by software writing 0 to it or by reading the ADC_RDATA register.
0
WDE
Analog watchdog event flag
0: No analog watchdog event
1: Analog watchdog event
GD32F1x0 User Manual
380
Set by hardware when the converted voltage crosses the values programmed in the
ADC_WLT and ADC_WDHT registers.
Cleared by software writing 0 to it.
12.4.2. Control register 0 (ADC_CTL0)
For GD32F130xx and GD32F150xx devices
Address offset: 0x04
Reset value: 0x0000 0000
This register has to be accessed by word (32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
RWDEN
IWDEN
Reserved
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
DISNUM[2:0]
DISIC
DISRC
ICA
WDSC
SM
EOICIE
WDEIE
EOCIE
WDCHSEL[4:0]
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31:24
Reserved
Must be kept at reset value
23
RWDEN
Regular channel analog watchdog enable
0: Analog watchdog regular channel disable
1: Analog watchdog regular channel enable
22
IWDEN
Inserted channel analog watchdog enable
0: Analog watchdog inserted channel disable
1: Analog watchdog inserted channel enable
21:16
Reserved
Must be kept at reset value
15:13
DISNUM[2:0]
Number of conversions in discontinuous mode
The number of channels to be converted after a trigger will be DISNUM[2:0]+1
12
DISIC
Discontinuous mode on inserted channels
0: Discontinuous mode on inserted channels disable
1: Discontinuous mode on inserted channels enable
11
DISRC
Discontinuous mode on regular channels
0: Discontinuous mode on regular channels disable
1: Discontinuous mode on regular channels enable
10
ICA
Inserted channel group convert automatically
0: Inserted channel group convert automatically disable
1: Inserted channel group convert automatically enable
GD32F1x0 User Manual
381
9
WDSC
When in scan mode, analog watchdog is effective on a single channel
0: Analog watchdog is effective on all channels
1: Analog watchdog is effective on a single channel
8
SM
Scan mode
0: scan mode enable
1: scan mode disable
7
EOICIE
Interrupt enable for EOIC
0: EOIC interrupt disable
1: EOIC interrupt enable
6
WDEIE
Interrupt enable for WDE
0: WDE interrupt disable
1: WDE interrupt enable
5
EOCIE
Interrupt enable for EOC
0: EOC interrupt disable
1: EOC interrupt enable
4:0
WDCHSEL[4:0]
Analog watchdog channel select
00000: ADC channel0
00001: ADC channel1
00010: ADC channel2
……
01111: ADC channel15
1xx00: ADC channel16
1xx01: ADC channel17
1xx1x: ADC channel18
“x” means 0 or 1
For GD32F170xx and GD32F190xx devices
Address offset: 0x04
Reset value: 0x0000 0000
This register has to be accessed by word (32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
DRES[1:0]
RWDEN
IWDEN
Reserved
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
DISNUM[2:0]
DISIC
DISRC
ICA
WDSC
SM
EOICIE
WDEIE
EOCIE
WDCHSEL[4:0]
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
GD32F1x0 User Manual
382
31:26
Reserved
Must be kept at reset value
25:24
DRES[1:0]
ADC resolution
00: 12bit;
01: 10bit;
10: 8bit;
11: 6bit
23
RWDEN
Regular channel analog watchdog enable
0: Analog watchdog regular channel disable
1: Analog watchdog regular channel enable
22
IWDEN
Inserted channel analog watchdog enable
0: Analog watchdog inserted channel disable
1: Analog watchdog inserted channel enable
21:16
Reserved
Must be kept at reset value
15:13
DISNUM[2:0]
Number of conversions in discontinuous mode
The number of channels to be converted after a trigger will be DISNUM[2:0]+1
12
DISIC
Discontinuous mode on inserted channels
0: Discontinuous mode on inserted channels disable
1: Discontinuous mode on inserted channels enable
11
DISRC
Discontinuous mode on regular channels
0: Discontinuous mode on regular channels disable
1: Discontinuous mode on regular channels enable
10
ICA
Inserted channel group convert automatically
0: Inserted channel group convert automatically disable
1: Inserted channel group convert automatically enable
9
WDSC
When in scan mode, analog watchdog is effective on a single channel
0: Analog watchdog is effective on all channels
1: Analog watchdog is effective on a single channel
8
SM
Scan mode
0: Scan mode enable
1: Scan mode disable
7
EOICIE
Interrupt enable for EOIC
0: EOIC interrupt disable
1: EOIC interrupt enable
6
WDEIE
Interrupt enable for WDE
0: WDE interrupt disable
1: WDE interrupt enable
5
EOCIE
Interrupt enable for EOC
GD32F1x0 User Manual
383
0: EOC interrupt disable
1: EOC interrupt enable
4:0
WDCHSEL[4:0]
Analog watchdog channel select
00000: ADC channel0
00001: ADC channel1
00010: ADC channel2
……
01111: ADC channel15
1xx00: ADC channel16
1xx01: ADC channel17
1xx1x: ADC channel18
“x” means 0 or 1
12.4.3. Control register 1 (ADC_CTL1)
Address offset: 0x08
Reset value: 0x0000 0000
This register has to be accessed by word (32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
VBA
TEN
TSV
REN
SWR
CST
SWIC
ST
ETE
RC
ETSRC[2:0]
Reserved
rw
rw
rw
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
ETEIC
ETSIC[2:0]
DAL
Reserved
DMA
Reserved
RSTCLB
CLB
CTN
ADCON
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31:25
Reserved
Must be kept at reset value
24
VBATEN
This bit is set and cleared by software to enable/disable the VBAT channel.
0: VBAT channel disabled
1: VBAT channel enabled
23
TSVREN
Channel 16 and 17 enable of ADC.
0: Channel 16 and 17 of ADC disable
1: Channel 16 and 17 of ADC enable
22
SWRCST
Start on regular channel.
Set 1 on this bit starts a conversion of a group of regular channels if ETSRC is 111.
It is set by software and cleared by software or by hardware after the conversion
starts.
21
SWICST
Start on inserted channel.
Set 1 on this bit starts a conversion of a group of inserted channels if ETSIC is 111.
GD32F1x0 User Manual
384
It is set by software and cleared by software or by hardware after the conversion
starts.
20
ETERC
External trigger enable for regular channel
0: External trigger for regular channel disable
1: External trigger for regular channel enable
19:17
ETSRC[2:0]
External trigger select for regular channel
000: TIMER0 CH0
001: TIMER0 CH1
010: TIMER0 CH2
011: TIMER1 CH1
100: TIMER2 TRGO
101: TIMER14 CH1
110: EXTI line 11
111: SWRCST
16
Reserved
Must be kept at reset value
15
ETEIC
External trigger enable for inserted channel
0: External trigger for inserted channel disable
1: External trigger for inserted channel enable
14:12
ETSIC[2:0]
External trigger select for inserted channel
000: TIMER0 TRGO
001: TIMER0 CH3
010: TIMER1 TRGO
011: TIMER1 CH0
100: TIMER2 CH3
101: TIMER14 TRGO
110: EXTI line15
111: SWICST
11
DAL
Data alignment
0: LSB alignment
1: MSB alignment
10:9
Reserved
Must be kept at reset value
8
DMA
DMA request enable.
0: DMA request disable
1: DMA request enable
7:4
Reserved
Must be kept at reset value
3
RSTCLB
Reset calibration
This bit is set by software and cleared by hardware after the calibration registers are
initialized.
0: Calibration register initialize done.
GD32F1x0 User Manual
385
1: Initialize calibration register start
2
CLB
ADC calibration
0: Calibration done
1: Calibration start
1
CTN
Continuous mode
0: Continuous mode disable
1: Continuous mode enable
0
ADCON
ADC ON. The ADC will be wake up when this bit is changed from low to high. When
this bit is high and “1” is written to it with other bits of this register unchanged, the
conversion will start.
0: ADC disable and power down
1: ADC enable
12.4.4. Sampling time register 0 (ADC_SAMPT0)
For GD32F130xx and GD32F150xx devices
Address offset: 0x0C
Reset value: 0x0000 0000
This register has to be accessed by word (32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
SPT17[2:0]
SPT16[2:0]
SPT15[2:1]
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
SPT15[0]
SPT14[2:0]
SPT13[2:0]
SPT12[2:0]
SPT11[2:0]
SPT10[2:0]
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31:24
Reserved
Must be kept at reset value
23:0
SPTn[2:0]
Channel n sampling time
000: 1.5 cycles
001: 7.5 cycles
010: 13.5 cycles
011: 28.5 cycles
100: 41.5 cycles
101: 55.5 cycles
110: 71.5 cycles
111: 239.5 cycles
Note: For GD32F130xx and GD32F150xx devices, the channel 17 and channel 18
sampling time are specified by the SPT17[2:0] bits in the ADC_SAMPT0
GD32F1x0 User Manual
386
For GD32F170xx and GD32F190xx devices
Address offset: 0x0C
Reset value: 0x0000 0000
This register has to be accessed by word (32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
SPT18[2:0]
SPT17[2:0]
SPT16[2:0]
SPT15[2:1]
rw
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
SPT15[0]
SPT14[2:0]
SPT13[2:0]
SPT12[2:0]
SPT11[2:0]
SPT10[2:0]
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31:27
Reserved
Must be kept at reset value
26:0
SPTn[2:0]
Channel n sampling time
000: 1.5 cycles
001: 7.5 cycles
010: 13.5 cycles
011: 28.5 cycles
100: 41.5 cycles
101: 55.5 cycles
110: 71.5 cycles
111: 239.5 cycles
12.4.5. Sampling time register 1 (ADC_SAMPT1)
Address offset: 0x10
Reset value: 0x0000 0000
This register has to be accessed by word (32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
SPT9[2:0]
SPT8[2:0]
SPT7[2:0]
SPT6[2:0]
SPT5[2:1]
rw
rw
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
SPT5[0]
SPT4[2:0]
SPT3[2:0]
SPT2[2:0]
SPT1[2:0]
SPT0[2:0]
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31:30
Reserved
Must be kept at reset value
29:0
SPTn[2:0]
Channel sampling time
000: 1.5 cycles
GD32F1x0 User Manual
387
001: 7.5 cycles
010: 13.5 cycles
011: 28.5 cycles
100: 41.5 cycles
101: 55.5 cycles
110: 71.5 cycles
111: 239.5 cycles
12.4.6. Inserted channel data offset registers (ADC_IOFFx) (x=0..3)
Address offset: 0x14-0x20
Reset value: 0x0000 0000
This register has to be accessed by word (32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
IOFF[11:0]
rw
Bits
Fields
Descriptions
31:12
Reserved
Must be kept at reset value
11:0
IOFF[11:0]
Data offset for inserted channel x
These bits will be subtracted from the raw converted data when converting inserted
channels. The conversion result can be read from the ADC_IDATAx registers.
12.4.7. Watchdog high threshold register (ADC_WDHT)
Address offset: 0x24
Reset value: 0x0000 0FFF
This register has to be accessed by word (32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
WDHT[11:0]
rw
Bits
Fields
Descriptions
GD32F1x0 User Manual
388
31:12
Reserved
Must be kept at reset value
11:0
WDHT[11:0]
Analog watchdog high threshold
These bits define the high threshold for the analog watchdog.
12.4.8. Watchdog low threshold register (ADC_WDLT)
Address offset: 0x28
Reset value: 0x0000 0000
This register has to be accessed by word (32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
WDLT[11:0]
rw
Bits
Fields
Descriptions
31:12
Reserved
Must be kept at reset value
11:0
WDLT[11:0]
Analog watchdog low threshold
These bits define the low threshold for the analog watchdog.
12.4.9. Regular sequence register 0 (ADC_RSQ0)
Address offset: 0x2C
Reset value: 0x0000 0000
This register has to be accessed by word (32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
RL[3:0]
RSQ16[4:1]
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RSQ16[0]
RSQ15[4:0]
RSQ14[4:0]
RSQ13[4:0]
rw
rw
rw
rw
Bits
Fields
Descriptions
31:24
Reserved
Must be kept at reset value
23:20
RL[3:0]
Regular channel group length.
The total number of conversion in regular group equals to RL[3:0]+1.
19:0
RSQn[4:0]
The channel number (0..18) are written to these bits to select a channel at the nth
GD32F1x0 User Manual
389
conversion in the regular channel group.
12.4.10. Regular sequence register 1 (ADC_RSQ1)
Address offset: 0x30
Reset value: 0x0000 0000
This register has to be accessed by word (32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
RSQ12[4:0]
RSQ11[4:0]
RSQ10[4:1]
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RSQ10[0]
RSQ9[4:0]
RSQ8[4:0]
RSQ7[4:0]
rw
rw
rw
rw
Bits
Fields
Descriptions
31:30
Reserved
Must be kept at reset value
29:0
RSQn[4:0]
The channel number (0..18) are written to these bits to select a channel at the nth
conversion in the regular channel group.
12.4.11. Regular sequence register 2 (ADC_RSQ2)
Address offset: 0x34
Reset value: 0x0000 0000
This register has to be accessed by word (32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
RSQ6[4:0]
RSQ5[4:0]
RSQ4[4:1]
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RSQ4[0]
RSQ3[4:0]
RSQ2[4:0]
RSQ1[4:0]
rw
rw
rw
rw
Bits
Fields
Descriptions
31:30
Reserved
Must be kept at reset value
29:0
RSQn[4:0]
The channel number (0..18) are written to these bits to select a channel at the nth
conversion in the regular channel group.
12.4.12. Inserted sequence register (ADC_ISQ)
Address offset: 0x38
GD32F1x0 User Manual
390
Reset value: 0x0000 0000
This register has to be accessed by word (32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
IL[1:0]
ISQ4[4:1]
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
ISQ4[0]
ISQ3[4:0]
ISQ2[4:0]
ISQ1[4:0]
rw
rw
rw
rw
Bits
Fields
Descriptions
31:22
Reserved
Must be kept at reset value
21:20
IL[1:0]
Inserted channel group length.
The total number of conversion in regular group equals to IL[1:0]+1.
19:0
ISQn[4:0]
The channel number (0..18) are written to these bits to select a channel at the nth
conversion in the inserted channel group.
Unlike the regular conversion sequence, the inserted channels are converted
starting from (4-IL[1:0]), if IL[1:0] length is less than 4.
IL
Insert channel order
11
ISQ0 >> ISQ1 >> ISQ2 >> ISQ3
10
ISQ1 >> ISQ2 >> ISQ3
01
ISQ2 >> ISQ3
00
ISQ3
12.4.13. Inserted data registers (ADC_IDATAx) (x= 0..3)
Address offset: 0x3C - 0x48
Reset value: 0x0000 0000
This register has to be accessed by word (32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
IDATAn[15:0]
r
Bits
Fields
Descriptions
31:16
Reserved
Must be kept at reset value
15:0
IDATAn[15:0]
Inserted number n conversion data
These bits contain the number n conversion result, which is read only.
GD32F1x0 User Manual
391
12.4.14. Regular data register (ADC_RDATA)
Address offset: 0x4C
Reset value: 0x0000 0000
This register has to be accessed by word (32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RDATA[15:0]
r
Bits
Fields
Descriptions
31:16
Reserved
Must be kept at reset value
15:0
RDATA[15:0]
Regular channel data
These bits contain the conversion result from regular channel, which is read only.
12.4.15. Oversampling control register (ADC_OVSAMPCTL) of GD32F170xx and
GD32F190xx devices
Address offset: 0x80
Reset value: 0x0000_0000
This register has to be accessed by word (32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
TOVS
OVSS[3:0]
OVSR[2:0]
Reserved
OVSEN
rw
rw
rw
rw
Bits
Fields
Descriptions
31:10
Reserved
Must be kept at reset value
9
TOVS
Triggered Oversampling
This bit is set and cleared by software.
0: All oversampled conversions for a channel are done consecutively after a trigger
1: Each oversampled conversion for a channel needs a trigger
Note: Software is allowed to write this bit only when ADCON=0 (which ensures that
no conversion is ongoing).
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8:5
OVSS[3:0]
Oversampling shift
This bit is set and cleared by software.
0000: No shift
0001: Shift 1-bit
0010: Shift 2-bits
0011: Shift 3-bits
0100: Shift 4-bits
0101: Shift 5-bits
0110: Shift 6-bits
0111: Shift 7-bits
1000: Shift 8-bits
Other codes reserved
Note: Software is allowed to write this bit only when ADCON =0 (which ensures that
no conversion is ongoing).
4:2
OVSR[2:0]
Oversampling ratio
This bit filed defines the number of oversampling ratio.
000: 2x
001: 4x
010: 8x
011: 16x
100: 32x
101: 64x
110: 128x
111: 256x
Note: Software is allowed to write this bit only when ADCON =0 (which ensures that
no conversion is ongoing).
1
Reserved
Must be kept at reset value
0
OVSEN
Oversampling Enable
This bit is set and cleared by software.
0: Oversampling disabled
1: Oversampling enabled
Note: Software is allowed to write this bit only when ADCON =0 (which ensures that
no conversion is ongoing).
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13. Digital-to-analog converter (DAC)
13.1. DAC Introduction
The 12-bit DAC module is a voltage output digital-to-analog converter. The DAC can be
configured in 8 or 12 bit mode and may be used in conjunction with the DMA controller. The
input data of the DAC could be left-aligned or right-aligned. The output voltage can optionally
be buffered for higher drive capability.
For GD32F150xx devices，the DAC module only has one DAC.
For GD32F190xx devices, the DAC module has two DACs, each with its own converter. In
DAC concurrent mode, conversions could be done independently or concurrently when both
DACs are grouped together for synchronous update operation.
13.2. DAC Main features
DAC main features are the following:
12-bit resolution. Left or right data alignment
DMA capability with underrun error detection
Conversion update synchronously
Conversion trigged by external triggers
Configurable internal buffer
Input voltage reference, VDDA
For GD32F190xx devices, additional features are shown below.
Two DAC converters: one output channel each
DAC independently or concurrently conversions
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Figure 13-1 shows the block diagram of DAC and Table 13-1 gives the pin description.
Figure 13-1. DAC block diagram
SWTRx
TIMER5_TRGO
TIMER2_TRGO
TIMER14_TRGO
TIMER1_TRGO
Trigger selectorx
DAC control register
DTSELx[2:0]
DMA requestx
DTENx
DHRx
12-bit
ODR
12-bit DAC
Control
logic
VDDA VSSA
DBOFFx
Buff
MUX2X1
DDMA ENx
DAC_OUT
12-bit
EXTI_9
Table 13-1. DAC pin
Name
Description
Signal type
VDDA
Analog power supply
Input, analog supply
VSSA
Ground for analog power supply
Input, analog supply ground
DAC_OUTx
DACx analog output
Analog output signal
Note: The corresponding GPIO pin is automatically connected to the analog converter output
(DAC_OUTx), Once the DAC is enabled. The GPIO pin should first be configured to analog
(AIN to avoid parasitic consumption).
For GD32F150xx devices, corresponding GPIO pin is PA4.
For GD32F190xx devices, corresponding GPIO pin is PA4 or PA5.
13.3. DAC Function description
13.3.1. DAC enable
The DAC can be powered on by setting the DENx bit in the DAC_CTL register. The DAC is
then enabled after a startup time tWAKEUP.
13.3.2. DAC output buffer enable
The DAC integrates output buffer(For GD32F150xx devices, there is an output buffer; For
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GD32F190xx devices, there are two output buffers ) which can be used to reduce the
impedance of output, so DAC can be directly connected to external loads without operational
amplifier. By the DBOFFx bit in the DAC_CTL register the DAC channel output buffer can be
enabled and disabled. Users can enable the output buffer when the load of the DAC is heavy.
13.3.3. DAC data format
Depending on the selected configuration mode, the data has to be written in the specified
register as described below:
Single DAC, there are three possibilities
1. right alignment 8-bit: DHx[11:4] bits are stored into DACx_R8DH [7:0] bits
2. right alignment 12-bit: DHx[11:0] bits are stored into DACx_R12DH [11:0] bits
3. left alignment 12-bit: DHx[11:0] bits are stored into DACx_L12DH [15:4] bits
The data can be shifted and stored into the DHx(Data Holding Register x, that are internal
non-memory-mapped registers) according to the value of the DACx_yyDH register. When a
software trigger or an external event trigger occurs, the DH register will be loaded into
DACx_DO register automatically.
Two DACs, there are three possibilities ( only for GD32F190xx devices)
1. Right alignment 8-bit: data for DAC0, DH0 [11:4] bits are stored into DACC_R8DH [7:0]
bits. Data for DAC1, DH1 [11:4] bits are stored into DACC_R8DH [15:8] bits.
2. Right alignment12-bit: data for DAC0 channel, DH0 [11:0] bits are stored into DACC_
R12DH [11:0] bits. Data for DAC1 channel, DH1 [11:0] bits are stored into DACC_
R12DH [27:16] bits.
3. Left alignment 12-bit: data for DAC0 channel, DH0 [11:0] bits are stored into DACC_
L12DH [15:4] bits. Data for DAC1 channel, DH1 [11:0] bits are stored into DACC_ L12DH
[31:20] bits.
The data can be shifted and stored into the DAC0_DH and DAC1_DH (Data Holding Register
x, that are internal non-memory-mapped registers) according to the value of the DACx_yyDH
register. When a software trigger or an external event trigger occurs, the DH register will be
loaded into DAC0_DO and DAC1_DO register automatically.
13.3.4. DAC conversion
Any data to be transferred by DAC should firstly be stored into the DH registers (DAC0_R8DH,
DAC0_R12DH, DAC0_L12DH, DAC1_R8DH, DAC1_R12DH, DAC1_L12DH, DACC_R8DH,
DACC_R12DH, DACC_L12DH).
If no hardware trigger is selected (DTENx bit in DAC_CTL register is reset), data stored in the
DACx_yyDH register are automatically transferred to the DACx_DO register. However, when
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a hardware trigger is selected (DTENx bit in DAC_CTL register is set), the transfer is
performed after the corresponding trigger occurs.
When the data from the DACx_yyDH register is loaded into the DACx_DO register, after the
time tSETTLING, the analog output is valid, and the value of tSETTLING is related to the power
supply voltage and the analog output load.
13.3.5. DAC output voltage
The analog output voltages on the DAC pin are determined by the following equation:
DAC output = VDDA*DO/4095
The digital input is linearly converted to an analog output voltage, its range is 0 to VDDA.
13.3.6. DMA request
Each DAC has a DMA function. For GD32F190xx devices, two DMA channel can be
respectively used for DAC DMA requests.
If the DDMAENx bit is set, a DAC DMA request will be generated when an external trigger
(not a software trigger) occurs. Then the value in the DACx_yyDH register will be transferred
to the DACx_DO register.
If a second external trigger arrives before the acknowledgement of the last request, the new
request will not be serviced, because the DAC DMA request is not queued. Than the DDUDRx
bit (DACx DMA underrun flag) in the DAC_STAT register is set, error status is reported. DMA
data transfer function is disable and no further processing DMA requests. DACx continues to
convert old data.
GD32F190xx devices:
In concurrent mode, if both DDMAENx bits are set, two DMA requests will be generated.
If you need one DMA request, only the corresponding DDMAENx bit should be set. In addition,
the application can handle both DAC channel in concurrent mode using one DMA request
and an independent DMA channel.
13.3.7. DAC trigger
Conversion can then be triggered by an external event (timer counter, external interrupt line),
when the DTENx control bit is set,
The last data in the DACx_yyDH register is transferred into the DACx_DO register, when a
DAC interface detects a selected timer TRGO output, or a rising edge on the selected external
interrupt line 9.
When the software trigger is selected and the SWTRx bit is set, the conversion will start.
SWTRx is reset by hardware.
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Table 13-2. External triggers of DAC
DTSELx[2:0]
Trigger Source
Trigger Type
000
TIMER5_TRGO
Internal on-chip signal
001
TIMER2_TRGO
010
reserved
011
TIMER14_TRGO
100
TIMER1_TRGO
101
reserved
110
EXTI_9
External signal
111
SWTRIG
Software trigger
13.3.8. DAC concurrent conversion for GD32F190xx devices
When the two DACs work at the same time, for more effective utilization of bus bandwidth in
applications, three concurrent registers can be used: DACC_R8DH, DACC_R12DH,
DACC_L12DH. You just need to access a unique register to realize driving both DAC
channels at the same time.
For the two DACs and these special registers, several possible conversion modes are
possible. The conversion mode in the case of only use one DAC channel, still can operate
through independent DHx registers.
All modes are described in the paragraphs below.
Independent trigger
To configure the DAC in this conversion mode, the following sequence is required:
Set the two DAC trigger enable bits DTEN0 and DTEN1
Set different values in the DTSEL0[2:0] and DTSEL1[2:0] bits to configure different
trigger sources
Load the DACs channel data into the required DACC_DH register (DACC_R8DH,
DACC_R12DH, DACC_L12DH)
When the DAC0 channel is triggered, the value of the DH0 register is transferred to DAC0_DO
(three APB1 clock cycles later).
When the DAC1 channel is triggered, the value of the DH1 register is transferred to DAC1_DO
(three APB1 clock cycles later).
Concurrent software start
In this conversion mode, follow the steps below to set the DAC:
Load the DACs channel data to the required DACC_DH register (DACC_R8DH,
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DACC_R12DH, DACC_L12DH)
In this mode, after one APB1 clock cycle, the value of the DH1 and DH2 registers is
immediately transferred to DAC0_DO and DAC1_DO.
Concurrent trigger
In this conversion mode, follow the steps below to set the DAC:
Set the two DAC trigger enable bits DTEN0 and DTEN1
Set the DTSEL0[2:0] and DTSEL1[2:0] bit to the same value, to configure the same
trigger source for both DAC
The data of two DACs conversion load to the required DACC_DH register (DACC_R8DH,
DACC_R12DH, DACC_L12DH)
If detects a rising edge of a trigger, the value of the DH1 and DH2 registers is immediately
transferred to DAC0_DO and DAC1_DO (three APB1 clock cycles later).
13.4. DAC registers
13.4.1. Control register (DAC_CTL)
For GD32F150xx devices
Address offset: 0x00
Reset value: 0x0000 0000
This register has to be accessed by word (32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
DDUDRIE0
DDMAEN0
Reserved
DTSEL0[2:0]
DTEN0
DBOFF0
DEN0
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31:14
Reserved
Must be kept at reset value
13
DDUDRIE0
DAC0 DMA Underrun Interrupt enable
0: DAC0 DMA Underrun Interrupt disabled
1: DAC0 DMA Underrun Interrupt enabled
12
DDMAEN0
DAC0 DMA enable
0: DAC0 DMA mode disabled
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1: DAC0 DMA mode enabled
11:6
Reserved
Must be kept at reset value
5:3
DTSEL0[2:0]
DAC0 trigger selection
These bits are only used if bit DTEN0 = 1 and select the external event used to
trigger DAC0.
000: TIMER5 TRGO event
001: TIMER2 TRGO event
010: Reserved
011: TIMER14 TRGO event
100: TIMER1 TRGO event
101: Reserved
110: External line9
111: Software trigger
2
DTEN0
DAC0 trigger enable
This bit is set and cleared by software to enable/disable DAC0 trigger.
0: DAC0 trigger disabled
1: DAC0 trigger enabled
1
DBOFF0
DAC0 output buffer turn off
This bit is set and cleared by software to enable/disable DAC0 output buffer.
0: DAC0 output buffer enabled
1: DAC0 output buffer turn off
0
DEN0
DAC0 enable
This bit is set and cleared by software to enable/disable DAC0.
0: DAC0 disabled
1: DAC0 enabled
For GD32F190xx devices
Address offset: 0x00
Reset value: 0x0000 0000
This register has to be accessed by word (32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
DDUDRIE1
DDMAEN1
Reserved
DTSEL1[2:0]
DTEN1
DBOFF1
DEN1
rw
rw
rw
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
DDUDRIE0
DDMAEN0
Reserved
DTSEL0[2:0]
DTEN0
DBOFF0
DEN0
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31:30
Reserved
Must be kept at reset value
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29
DDUDRIE1
DAC1 DMA Underrun Interrupt enable
0: DAC1 DMA Underrun Interrupt disabled
1: DAC1 DMA Underrun Interrupt enabled
28
DDMAEN1
DAC1 DMA enable
0: DAC1 DMA mode disabled
1: DAC1 DMA mode enabled
27:22
Reserved
Must be kept at reset value
21:19
DTSEL1[2:0]
DAC1 trigger selection
These bits are only used if bit DTEN1 = 1 and select the external event used to
trigger DAC1.
000: TIMER5 TRGO event
001: TIMER2 TRGO event
010: Reserved
011: TIMER14 TRGO event
100: TIMER1 TRGO event
101: Reserved
110: External line9
111: Software trigger
18
DTEN1
DAC1 trigger enable
This bit is set and cleared by software to enable/disable DAC1 trigger.
0: DAC1 trigger disabled
1: DAC1 trigger enabled
17
DBOFF1
DAC1 output buffer turn off
This bit is set and cleared by software to enable/disable DAC1 output buffer.
0: DAC1 output buffer enabled
1: DAC1 output buffer turn offd
16
DEN1
DAC1 enable
This bit is set and cleared by software to enable/disable DAC1.
0: DAC1 disabled
1: DAC1 enabled
15:14
Reserved
Must be kept at reset value
13
DDUDRIE0
DAC0 DMA Underrun Interrupt enable
0: DAC0 DMA Underrun Interrupt disabled
1: DAC0 DMA Underrun Interrupt enabled
12
DDMAEN0
DAC0 DMA enable
0: DAC0 DMA mode disabled
1: DAC0 DMA mode enabled
11:6
Reserved
Must be kept at reset value
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5:3
DTSEL0[2:0]
DAC0 trigger selection
These bits are only used if bit DTEN0 = 1 and select the external event used to
trigger DAC0.
000: TIMER5 TRGO event
001: TIMER2 TRGO event
010: Reserved
011: TIMER14 TRGO event
100: TIMER1 TRGO event
101: Reserved
110: External line9
111: Software trigger
2
DTEN0
DAC0 trigger enable
This bit is set and cleared by software to enable/disable DAC0 trigger.
0: DAC0 trigger disabled
1: DAC0 trigger enabled
1
DBOFF0
DAC0 output buffer turn off
This bit is set and cleared by software to enable/disable DAC0 output buffer.
0: DAC0 output buffer enabled
1: DAC0 output buffer turn off
0
DEN0
DAC0 enable
This bit is set and cleared by software to enable/disable DAC0.
0: DAC0 disabled
1: DAC0 enabled
13.4.2. Software trigger register (DAC_SWT)
For GD32F150xx devices
Address offset: 0x04
Reset value: 0x0000 0000
This register has to be accessed by word (32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
SWTR0
w
Bits
Fields
Descriptions
31:1
Reserved
Must be kept at reset value
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0
SWTR0
DAC0 software trigger, cleared by hardware
0: Software trigger disabled
1: Software trigger enabled
For GD32F190xx devices
Address offset: 0x04
Reset value: 0x0000 0000
This register has to be accessed by word (32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
SWTR1
SWTR0
w
w
Bits
Fields
Descriptions
31:2
Reserved
Must be kept at reset value
1
SWTR1
DAC1 software trigger, cleared by hardware
0: Software trigger disabled
1: Software trigger enabled
0
SWTR0
DAC0 software trigger, cleared by hardware
0: Software trigger disabled
1: Software trigger enabled
13.4.3. DAC0 12-bit right-aligned data holding register (DAC0_R12DH)
Address offset: 0x08
Reset value: 0x0000 0000
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
DAC0_DH[11:0]
rw
Bits
Fields
Descriptions
31:12
Reserved
Must be kept at reset value
11:0
DAC0_DH[11:0]
DAC0 12-bit right-aligned data
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These bits are written by software which specifies 12-bit data for DAC0.
13.4.4. DAC0 12-bit left-aligned data holding register (DAC0_L12DH)
Address offset: 0x0C
Reset value: 0x0000 0000
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
DAC0_DH[11:0]
Reserved
rw
Bits
Fields
Descriptions
31:16
Reserved
Must be kept at reset value
15:4
DAC0_DH[11:0]
DAC0 12-bit left-aligned data
These bits are written by software which specifies 12-bit data for DAC0.
3:0
Reserved
Must be kept at reset value
13.4.5. DAC0 8-bit right-aligned data holding register (DAC0_R8DH)
Address offset: 0x10
Reset value: 0x0000 0000
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
DAC0_DH[7:0]
rw
Bits
Fields
Descriptions
31:8
Reserved
Must be kept at reset value
7:0
DAC0_DH[7:0]
DAC0 8-bit right-aligned data
These bits are written by software which specifies 8-bit data for DAC0.
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13.4.6. DAC1 12-bit right-aligned data holding register (DAC1_R12DH) of
GD32F190xx devices
Address offset: 0x14
Reset value: 0x0000 0000
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
DAC1_DH[11:0]
rw
Bits
Fields
Descriptions
31:12
Reserved
Must be kept at reset value
11:0
DAC1_DH[11:0]
DAC1 12-bit right-aligned data
These bits are written by software which specifies 12-bit data for DAC1.
13.4.7. DAC1 12-bit left-aligned data holding register (DAC1_L12DH) of
GD32F190xx devices
Address offset: 0x18
Reset value: 0x0000 0000
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
DAC1_DH[11:0]
Reserved
rw
Bits
Fields
Descriptions
31:16
Reserved
Must be kept at reset value
15:4
DAC1_DH[11:0]
DAC1 12-bit left-aligned data
These bits are written by software which specifies 12-bit data for DAC1.
3:0
Reserved
Must be kept at reset value
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13.4.8. DAC1 8-bit right-aligned data holding register (DAC1_R8DH) of
GD32F190xx devices
Address offset: 0x1C
Reset value: 0x0000 0000
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
DAC1_DH[7:0]
rw
Bits
Fields
Descriptions
31:8
Reserved
Must be kept at reset value
7:0
DAC1_DH[7:0]
DAC1 8-bit right-aligned data
These bits are written by software which specifies 8-bit data for DAC1.
13.4.9. DAC concurrent mode 12-bit right-aligned data holding register
(DACC_R12DH) of GD32F190xx devices
Address offset: 0x20
Reset value: 0x0000 0000
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
DAC1_DH[11:0]
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
DAC0_DH[11:0]
rw
Bits
Fields
Descriptions
31:28
Reserved
Must be kept at reset value
27:16
DAC1_DH[11:0]
DAC1 12-bit right-aligned data
These bits are written by software which specifies 12-bit data for DAC1.
15:12
Reserved
Must be kept at reset value
11:0
DAC0_DH[11:0]
DAC0 12-bit right-aligned data
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These bits are written by software which specifies 12-bit data for DAC0.
13.4.10. DAC concurrent mode 12-bit left-aligned data holding register
(DACC_L12DH) of GD32F190xx devices
Address offset: 0x24
Reset value: 0x0000 0000
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
DAC1_DH[11:0]
Reserved
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
DAC0_DH[11:0]
Reserved
rw
Bits
Fields
Descriptions
31:20
DAC1_DH[11:0]
DAC1 12-bit left-aligned data
These bits are written by software which specifies 12-bit data for DAC1.
19:16
Reserved
Must be kept at reset value
15:4
DAC0_DH[11:0]
DAC0 12-bit left-aligned data
These bits are written by software which specifies 12-bit data for DAC1.
3:0
Reserved
Must be kept at reset value
13.4.11. DAC concurrent mode 8-bit right-aligned data holding register
(DACC_R8DH) of GD32F190xx devices
Address offset: 0x28
Reset value: 0x0000 0000
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
DAC1_DH[7:0]
DAC0_DH[7:0]
rw
rw
Bits
Fields
Descriptions
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31:16
Reserved
Must be kept at reset value
15:8
DAC1_DH[7:0]
DAC1 8-bit right-aligned data
These bits are written by software which specifies 8-bit data for DAC1.
7:0
DAC0_DH[7:0]
DAC0 8-bit right-aligned data
These bits are written by software which specifies 8-bit data for DAC0.
13.4.12. DAC0 data output register (DAC0_DO)
Address offset: 0x2C
Reset value: 0x0000 0000
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
DAC0_DO [11:0]
r
Bits
Fields
Descriptions
31:12
Reserved
Must be kept at reset value
11:0
DAC0_DO [11:0]
DAC0 output data
These bits are read-only, they contain data output for DAC0.
13.4.13. DAC1 data output register (DAC1_DO) of GD32F190xx devices
Address offset: 0x30
Reset value: 0x0000 0000
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
DAC1_DO [11:0]
r
Bits
Fields
Descriptions
31:12
Reserved
Must be kept at reset value
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11:0
DAC1_DO [11:0]
DAC1 output data
These bits are read-only, they contain data output for DAC1.
13.4.14. Status register (DAC_STAT)
For GD32F150xx devices
Address offset: 0x34
Reset value: 0x0000 0000
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
DDUDR0
Reserved
rc_w1
Bits
Fields
Descriptions
31:14
Reserved
Must be kept at reset value
13
DDUDR0
DAC0 DMA underrun flag
This bit is set by hardware and cleared by software (by writing it to 1).
0: No DMA underrun error condition occurred
1: DMA underrun error condition occurred (the frequency of the current selected
trigger that is driving DAC conversion is higher than the DMA service capability rate)
12:0
Reserved
Must be kept at reset value
For GD32F190xx devices
Address offset: 0x34
Reset value: 0x0000 0000
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
DDUDR1
Reserved
rc_w1
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
DDUDR0
Reserved
rc_w1
Bits
Fields
Descriptions
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31:30
Reserved
Must be kept at reset value
29
DDUDR1
DAC1 DMA underrun flag
This bit is set by hardware and cleared by software (by writing it to 1).
0: No DMA underrun error condition occurred
1: DMA underrun error condition occurred (the frequency of the current selected
trigger that is driving DAC conversion is higher than the DMA service capability rate)
28:14
Reserved
Must be kept at reset value
13
DDUDR0
DAC0 DMA underrun flag
This bit is set by hardware and cleared by software (by writing it to 1).
0: No DMA underrun error condition occurred
1: DMA underrun error condition occurred (the frequency of the current selected
trigger that drives DAC conversion is higher than the DMA service capability rate)
12:0
Reserved
Must be kept at reset value
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14. Inter-integrated circuit (I2C) interface
14.1. Introduction
The I2C (inter-integrated circuit) module provides an I2C interface which is an industry
standard two-line serial interface for MCU to communicate with external I2C interface. I2C
bus uses two serial lines: a serial data line, SDA, and a serial clock line, SCL.
The I2C interface implements standard I2C protocol at standard or fast speed as well as CRC
calculation and checking, SMBus (system management bus) and PMBus (power
management bus). It also supports multi-master I2C bus. The I2C interface provides DMA
mode for users to reduce CPU overload.
14.2. Main features
Parallel-bus to I2C-bus protocol converter and interface
Both master and slave functions with the same interface
Bi-directional data transfer between master and slave
Supports 7-bit and 10-bit addressing and general call addressing
Multi-master capability
Supports Standard Speed (up to 100 kHz) and Fast Speed (up to 400 kHz)
Configurable SCL stretching in slave mode
Supports DMA mode
SMBus 2.0 and PMBus compatible
2 Interrupts: one for successful byte transmission and the other for error event
Optional PEC (packet error checking) generation and check
For GD32F170xx and GD32F190xx devices, additional features are shown below.
Support SAM_V mode
14.3. Function description
Figure 14-1 below provides details on the internal configuration of the I2C interface.
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Figure 14-1. I2C module block diagram
Data Register
APB Bus
Shift RegisterSDA Controller
CRC Calculation /
Check
PEC register
SCL Controller
Timing and
Control Logic
Control Registers
Status Flags
SDA
SCL
SMBA
DMA/ Interrupts
Table 14-1. Definition of I2C-bus terminology
Term
Description
Transmitter
the device which sends data to the bus
Receiver
the device which receives data from the bus
Master
the device which initiates a transfer, generates clock signals and terminates
a transfer
Slave
the device addressed by a master
Multi-master
more than one master can attempt to control the bus at the same time
without corrupting the message
Synchronization
procedure to synchronize the clock signals of two or more devices
Arbitration
procedure to ensure that, if more than one master simultaneously tries to
control the bus, only one is allowed to do so and the winning message is
not corrupted
14.3.1. SDA and SCL lines
The I2C module has two external lines, the serial data SDA and serial clock SCL lines. The
two wires carry information between the devices connected to the bus.
Both SDA and SCL are bidirectional lines, connected to a positive supply voltage via ccurrent-
source or pull-up resistor. When the bus is free, both lines are HIGH. The output stages of
devices connected to the bus must have an open-drain or open-collect or to perform the wired-
AND function. Data on the I2C-bus can be transferred at rates of up to 100 kbit/s in the
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standard-mode and up to 400 kbit/s in the fast mode. Due to the variety of different technology
devices (CMOS, NMOS, bipolar) that can be connected to the I2C-bus, the levels of the logical
‘0’ (LOW) and ‘1’ (HIGH) are not fixed and depend on the associated level of VDD.
14.3.2. Data validation
The data on the SDA line must be stable during the HIGH period of the clock. The HIGH or
LOW state of the data line can only change when the clock signal on the SCL line is LOW
(see Figure 14-2). One clock pulse is generated for each data bit transferred.
Figure 14-2. Data validation
14.3.3. START and STOP condition
All transactions begin with a START (S) and are terminated by a STOP (P) (see Figure 14-3).
A HIGH to LOW transition on the SDA line while SCL is HIGH defines a START condition. A
LOW to HIGH transition on the SDA line while SCL is HIGH defines a STOP condition.
Figure 14-3. START and STOP condition
14.3.4. Clock synchronization
Two masters can begin transmitting on a free bus at the same time and there must be a
method for deciding which takes control of the bus and complete its transmission. This is done
by clock synchronization and arbitration. In single master systems, clock synchronization and
arbitration are not needed.
Clock synchronization is performed using the wired-AND connection of I2C interfaces to the
SCL line. This means that a HIGH to LOW transition on the SCL line causes the masters
concerned to start counting off their LOW period and, once a master clock has gone LOW, it
holds the SCL line in that state until the clock HIGH state is reached (see Figure 14-4).
However, if another clock is still within its LOW period, the LOW to HIGH transition of this
clock may not change the state of the SCL line. The SCL line is therefore held LOW by the
SDA
SCL
START
SDA
SCL
STOP
SDA
SCL
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master with the longest LOW period. Masters with shorter LOW periods enter a HIGH wait-
state during this time.
Figure 14-4. Clock synchronization
14.3.5. Arbitration
Arbitration, like synchronization, refers to a portion of the protocol required only if more than
one master is used in the system. Slaves are not involved in the arbitration procedure.
A master may start a transfer only if the bus is free. Two masters may generate a START
condition within the minimum hold time of the START condition which results in a valid START
condition on the bus. Arbitration is then required to determine which master will complete its
transmission.
Arbitration proceeds bit by bit. During every bit, while SCL is HIGH, each master checks to
see if the SDA level matches what it has sent. This process may take many bits. Two masters
can actually complete an entire transaction without error, as long as the transmissions are
identical. The first time a master tries to send a HIGH, but detects that the SDA level is LOW,
the master knows that it has lost the arbitration and turns off its SDA output driver. The other
master goes on to complete its transaction.
Figure 14-5. SDA Line arbitration
14.3.6. I2C communication flow
Each I2C device is recognized by a unique address (whether it is a microcontroller, LCD driver,
memory or keyboard interface) and can operate as either a transmitter or receiver, depending
on the function of the device.
An I2C slave will continue to detect addresses after a START condition on I2C bus and
compare the detected address with its own address which is programmable by software.
Once the two addresses match, the I2C slave will send an ACK to the I2C bus and responses
Count
Wait
0ns
25ns
50ns
75ns
CLK1
CLK2
SCL
1
0
1
1
1
0
1
0
1
0
1
0
Arbitration Lost
SDA from master1
SDA from master2
SDA
SCL
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to the following command on I2C bus: transmitting or receiving desired data. Additionally, if
General Call is enabled by software, an I2C slave always responses to a General Call
Address (0x00). The I2C block support both 7-bit and 10-bit addresses.
An I2C master always initiates or end a transfer using START or STOP condition and it’s also
responsible for SCL clock generation.
Figure 14-6. I2C communication flow with 7-bit address.
Figure 14-7. I2C communication flow with 10-bit address.
14.3.7. Programming model
An I2C device such as LCD driver may be only a receiver, whereas a memory can both
receive and transmit data. In addition to transmitters and receivers, devices can also be
considered as masters or slaves when performing data transfers. A master is the device which
initiates a data transfer on the bus and generates the clock signals to permit that transfer. At
that time, any device addressed is considered a slave.
An I2C device is able to transmit or receive data whether it’s a master or a slave, thus, there’re
4 operation modes for an I2C device:
Master Transmitter
Master Receiver
Slave Transmitter
Slave Receiver
I2C block supports all of the four I2C modes. After system reset, it works in slave mode. If it’s
programmed by software and finished sending a START condition on I2C bus, it changes into
master mode. The I2C changes back to slave mode after it’s programmed by software and
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finished sending a STOP condition on I2C bus.
Programming model in slave transmitting mode
As it shows in figure below, software should follow these steps to operate I2C block in slave
mode for transmitting some data to the I2C bus:
1. First of all, software should enable I2C peripheral clock as well as configure clock related
registers in I2C_CTL1 to make sure correct I2C timing. After enabled and configured,
I2C operates in its default slave state and waits for START condition followed by address
on I2C bus.
2. After receiving a START condition followed by a matched address, either in 7-bit format
or in 10-bit format, the I2C hardware sets the ADDSEND bit in I2C_STAT0 register, which
should be monitored by software either by polling or interrupt. Now software should read
I2C_STAT0 and then I2C_STAT1 to clear ADDSEND bit. If the address is in 10-bit format,
the I2C master should then generate a repeated START (Sr) condition and send a header
to the I2C bus. The slave sets ADDSEND bit again after it detects the repeated START
(Sr) condition and the following header. Software also clears the ADDSEND bit again by
reading I2C_STAT0 and then I2C_STAT1.
3. Now I2C enters data transmission stage and hardware sets TBE bit because both the
shift register and data register I2C_DATA are empty. Software now write the first byte
data to I2C_DATA register, but the TBE is not cleared because the written byte in
I2C_DATA is moved to internal shift register immediately. The I2C begins to transmit data
to I2C bus as soon as shift register is not empty.
4. During the first byte’s transmission, software can write the second byte to I2C_DATA,
and this time TBE is cleared because neither I2C_DATA nor shift register is empty.
5. Any time TBE is set, software can write a byte to I2C_DATA as long as there are still data
to be transmitted.
6. During the second last byte’s transmission, software writes the last data to I2C_DATA to
clear the TBE flag and doesn’t care TBE anymore. So TBE will be seted after the byte’s
transmission and not cleared until a STOP condition.
7. I2C master doesn’t acknowledge to the last byte according to the I2C protocol, so after
sending the last byte, I2C slave will wait for the STOP condition on I2C bus and sets
AERR (Acknowledge Error) bit to notify software that transmission completes. Software
clears AERR bit by writing 0 to it.
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Figure 14-8. Programming model for slave transmitting
IDLE
Master generates START
condition
Master sends Address
Slave sends Acknowledge
Master generates repeated
START condition
Master sends header
Slave sends Acknowledge
SCL stretched by slave
Slave sends DATA(1)
Master sends Acknowledge
……（Data transmission）
Slave sends DATA(N-2)
Master sends Acknowledge
Slave sends DATA(N)
Master DON'T send Ack
Master generates STOP
condition
1) Software initialization
Set ADDSEND 2) Clear ADDSEND
Set ADDSEND 2) Clear ADDSEND
Set TBE
Set TBE
Set TBE
Set AE
Clear TBE
3) Write DATA(1) to
I2C_DATA
Write DATA(x) to I2C_DATA
Set TBE
4) Write DATA(2) to
I2C_DATA
5) Write DATA(3) to
I2C_DATA
6)Write DATA(N) to
I2C_DATA
Slave sends DATA(N-1)
Master sends Acknowledge
Set TBE
7) Clear AE
I2C Line State Hardware Action Software Flow
Master sends Header
Slave sends Acknowledge
Programming model in slave receiving mode
As it shows in figure below, software should follow these steps to operate I2C block in slave
mode for receiving some data from the I2C bus:
1. First of all, software should enable I2C peripheral clock as well as configure clock related
registers in I2C_CTL1 to make sure correct I2C timing. After enabled and configured,
I2C operates in its default slave state and waits for START condition followed by address
on I2C bus.
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2. After receiving a START condition followed by a matched 7-bit or 10-bit address, the I2C
hardware sets the ADDSEND bit in I2C status register, which should be monitored by
software either by polling or interrupt. Now software should read I2C_STAT0 and then
I2C_STAT1 to clear ADDSEND bit. The I2C begins to receive data to I2C bus as soon
as ADDSEND bit is cleared.
3. As soon as the first byte is received, RBNE is set by hardware. Software now can read
the first byte from I2C_DATA and RBNE is cleared as well.
4. Any time RBNE is set, software can read a byte from I2C_DATA.
5. After last byte is received, RBNE is set. Software reads the last byte.
6. STPDET bit is set when I2C detects a STOP condition on I2C bus and software reads
I2C_STAT0 and then writes I2C_CTL0 to clear the STPDET bit.
Figure 14-9. Programming model for slave receiving
IDLE
Master generates START
condition
Master sends Header
Slave sends Acknowledge
Master sends Address
Slave sends Acknowledge
SCL stretched by slave
Master sends DATA(1)
Slave sends Acknowledge
……（Data transmission）
Master sends DATA(N)
Slave sends Acknowledge
Master generates STOP
condition
Set ADDSEND 2) Clear ADDSEND
Set RBNE
Set STPDET
4) Read DATA(x)
Set RBNE 3) Read DATA(1)
5) Read DATA(N)
6) Clear STPDET
I2C Line State Hardware Action Software Flow
Set RBNE
1) Software initialization
Programming model in master transmitting mode
As it shows in figure below, software should follow these steps to operate I2C block in master
mode for transmitting some data to the I2C bus:
1. First of all, software should enable I2C peripheral clock as well as configure clock related
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registers in I2C_CTL1 to make sure correct I2C timing. After enabled and configured,
I2C operates in its default slave state and waits for START condition followed by address
on I2C bus.
2. Software set START bit requesting I2C to generate a START condition to I2C bus.
3. After sending a START condition, the I2C hardware sets the SBSEND bit in I2C status
register and enters master mode. Now software should clear the SBSEND bit by reading
I2C_STAT0 and then writing a 7-bit address or header of a 10-bit address to I2C_DATA.
I2C begins to send address or header to I2C bus as soon as SBSEND bit is cleared. If
the address sent is a header of 10-bit address, the hardware sets ADD10SEND bit after
sending header and software should clear the ADD10SEND bit by reading I2C_STAT0
and writing 10-bit lower address to I2C_DATA.
4. After the 7-bit or 10-bit address is sent, the I2C hardware sets the ADDSEND bit and
software should clear the ADDSEND bit by reading I2C_STAT0 and then I2C_STAT1.
5. Now I2C enters data transmission stage and hardware sets TBE bit because both the
shift register and data register I2C_DATA are empty. Software now write the first byte
data to I2C_DATA register, but the TBE is not cleared because the written byte in
I2C_DATA is moved to internal shift register immediately. The I2C begins to transmit data
to I2C bus as soon as shift register is not empty.
6. During the first byte’s transmission, software can write the second byte to I2C_DATA,
and this time TBE is cleared because neither I2C_DATA nor shift register is empty.
7. Any time TBE is set, software can write a byte to I2C_DATA as long as there are still data
to be transmitted.
8. During the second last byte’s transmission, software writes the last data to I2C_DATA to
clear the TBE flag and doesn’t care TBE anymore. So TBE will be asserted after the
byte’s transmission and not cleared until a STOP condition.
9. After sending the last byte, I2C master sets BTC bit because both shift register and
I2C_DATA are empty. Software should program a STOP request now, and the I2C clears
both TBE and BTC flags after sending a STOP condition.
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Figure 14-10. Programming model for master transmitting
IDLE
Master generates START
condition
Master sends Address
Slave sends Acknowledge
Master sends Header
Slave sends Acknowledge
SCL stretched by master
Master sends DATA(1)
Slave sends Acknowledge
……（Data transmission）
Master sends DATA(N-2)
Slave sends Acknowledge
Master sends DATA(N)
Slave sends Acknowledge
Master generates STOP
condition
1) Software initialization
Set ADD10SEND 4) Clear ADD10SEND
Set ADDSEND 4) Clear ADDSEND
Set TBE
Set TBE
Set TBE
Set BTC
5) Write DATA(1) to
I2C_DATA
Write DATA(x) to I2C_DATA
Set TBE
6) Write DATA(2) to
I2C_DATA
7) Write DATA(3) to
I2C_DATA
8)Write DATA(N) to
I2C_DATA
Master sends DATA(N-1)
Slave sends Acknowledge
Set TBE
9) Set GENSTP
I2C Line State Hardware Action Software Flow
2) Set GENSTA
Set SBSEND
SCL stretched by master 3) Clear SBSEND
SCL stretched by master
SCL stretched by master
Programming model in master receiving mode
In master receiving mode, a master is responsible for generating NACK for the last byte
reception and then sending STOP condition on I2C bus. So, special attention should be paid
to ensure the correct ending of data receiving. Two solutions for master receiving is provided
here for your application: Solution A and B. Solution A requires the software’s quick response
to I2C events, while Solution B doesn’t.
Solution A
1. First of all, software should enable I2C peripheral clock as well as configure clock related
registers in I2C_CTL1 to make sure correct I2C timing. After enabled and configured,
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I2C operates in its default slave state and waits for START condition followed by address
on I2C bus.
2. Software set START bit requesting I2C to generate a START condition to I2C bus.
3. After sending a START condition, the I2C hardware sets the SBSEND bit in I2C status
register and enters master mode. Now software should clear the SBSEND bit by reading
I2C_STAT0 and then writing a 7-bit address or header of a 10-bit address to I2C_DATA.
I2C begins to send address or header to I2C bus as soon as SBSEND bit is cleared. If
the address sent is a header of 10-bit address, the hardware sets ADD10SEND bit after
sending header and software should clear the ADD10SEND bit by reading I2C_STAT0
and writing 10-bit lower address to I2C_DATA.
4. After the 7-bit or 10-bit address is sent, the I2C hardware sets the ADDSEND bit and
software should clear the ADDSEND bit by reading I2C_STAT0 and then I2C_STAT1. If
the address is in 10-bit format, software should then set START bit again to generate a
repeated START condition on I2C bus and SBSEND is set after the repeated START is
sent out. Software should clear the SBSEND bit by reading I2C_STAT0 and writing
header to I2C_DATA. Then the header is sent out to I2C bus, and ADDSEND is set again.
Software should again clear ADDSEND by reading I2C_STAT0 and then I2C_STAT1.
5. As soon as the first byte is received, RBNE is set by hardware. Software now can read
the first byte from I2C_DATA and RBNE is cleared as well.
6. Any time RBNE is set, software can read a byte from I2C_DATA.
7. After the second last byte is received, the software should clear ACKEN bit and set STOP
bit. These actions should complete before the end of the last byte’s receiving to ensure
that NACK is sent for the last byte.
8. After last byte is received, RBNE is set. Software reads the last byte. I2C doesn’t send
ACK to the last byte and generate a STOP condition after the transmission of the last
byte.
Above steps require byte number N>1. If N=1, Step 7 should be performed after Step 4 and
completed before the end of the single byte’s receiving.
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Figure 14-11. Programming model for master receiving using Solution A
IDLE
START Condition
Master sends Address
Slave sends Acknowledge
Master sends Header
Slave sends Acknowledge
SCL stretched by master
Slave sends DATA(1)
Master sends Acknowledge
……（Data transmission）
Slave sends DATA(N)
Master DON'T send Ack
Master generates STOP
condition
1) Software initialization
Set ADD10SEND 4) Clear ADD10SEND
Set ADDSEND 4) Clear ADDSEND
Set RBNE
Set RBNE
Read DATA(x)
Set RBNE 5) Read DATA(1)
Slave sends DATA(N-1)
Master sends Acknowledge
Set RBNE
8) Read DATA(N)
I2C Line State Hardware
Action Software Flow
2) Set GENSTA
Set SBSEND
SCL Strechd 3) Clear SBSEND
SCL stretched by master
4) Set GENSTA
Master generates repeated
START condition Set SBSEND 4) Clear SBSEND
SCL stretched by master
Master sends Header
Slave sends Acknowledge
Set ADDSEND 4) Clear ADDSEND
SCL stretched by master
6) Read DATA(N-1)
7) Clear ACKEN，Set
GENSTP
Solution B
1. First of all, software should enable I2C peripheral clock as well as configure clock related
registers in I2C_CTL1 to make sure correct I2C timing. After enabled and configured,
I2C operates in its default slave state and waits for START condition followed by address
on I2C bus.
2. Software set START bit requesting I2C to generate a START condition to I2C bus.
3. After sending a START condition, the I2C hardware sets the SBSEND bit in I2C status
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register and enters master mode. Now software should clear the SBSEND bit by reading
I2C_STAT0 and then writing a 7-bit address or header of a 10-bit address to I2C_DATA.
I2C begins to send address or header to I2C bus as soon as SBSEND bit is cleared. If
the address sent is a header of 10-bit address, the hardware sets ADD10SEND bit after
sending header and software should clear the ADD10SEND bit by reading I2C_STAT0
and writing 10-bit lower address to I2C_DATA.
4. After the 7-bit or 10-bit address is sent, the I2C hardware sets the ADDSEND bit and
software should clear the ADDSEND bit by reading I2C_STAT0 and then I2C_STAT1. If
the address is in 10-bit format, software should then set START bit again to generate a
repeated START condition on I2C bus and SBSEND is set after the repeated START is
sent out. Software should clear the SBSEND bit by reading I2C_STAT0 and writing
header to I2C_DATA. Then the header is sent out to I2C bus, and ADDSEND is set again.
Software should again clear ADDSEND by reading I2C_STAT0 and then I2C_STAT1.
5. As soon as the first byte is received, RBNE is set by hardware. Software now can read
the first byte from I2C_DATA and RBNE is cleared as well.
6. Any time RBNE is set, software can read a byte from I2C_DATA until the master receives
N-3 bytes.
7. As shown in Figure 14-12, the N-2 byte is not read out by software, so after the N-1 byte
is received, both BTC and RBNE are asserted. The bus is stretched by master to prevent
the reception of the last byte. Then software should clear ACKEN bit.
8. Software reads out N-2 byte, clearing BTC. After this the N-1 byte is moved from shift
register to I2C_DATA and bus is released and begins to receive the last byte.
9. After last byte is received, both BTC and RBNE is set again. Software sets STOP bit and
master sends out a STOP condition on bus.
10. Software reads the N-1 byte, clearing BTC. After this the last byte is moved from shift
register to I2C_DATA.
11. Software reads the last byte, clearing RBNE.
Above steps require that byte number N>2. N=1 or N=2 are similar:
N=1
In Step4, software should reset ACK bit before clearing ADDSEND bit and set STOP bit after
clearing ADDSEND bit. Step 5 is the last step when N=1.
N=2
In Step 2, software should set POAP bit before set START bit. In Step 4, software should
reset ACKEN bit before clearing ADDSEND bit. In Step 5, software should wait until BTC is
set and then set STOP bit and reads I2C_DATA twice.
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Figure 14-12. Programming model for master receiving using Solution B
IDLE
Master generates START
condition
Master sends Address
Slave sends Acknowledge
Master sends Header
Slave sends Acknowledge
SCL stretched by master
Slave sends DATA(1)
Master sends Acknowledge
……（Data transmission）
Slave sends DATA(N)
Master DON'T send Ack
Master generates STOP
condition
1) Software initialization
Set ADD10SEND 4) Clear ADD10SEND
Set ADDSEND 4) Clear ADDSEND
Set RBNE
Set RBNE and BTC
6) Read DATA(N-3)
Set RBNE 5) Read DATA(1)
Slave sends DATA(N-1)
Master sends Acknowledge
Set RBNE
8) Read DATA(N-2)
I2C Line State Hardware Action Software Flow
2) Set GENSTA
Set SBSEND
SCL stretched by master 3) Clear SBSEND
SCL stretched by master
4) Set GENSTA
Master generates repeated
START condition Set SBSEND 4) Clear SBSEND
SCL stretched by master
Master sends Header
Slave sends Acknowledge
Set ADDSEND 4) Clear ADDSEND
SCL stretched by master
7) Clear ACKEN
Slave sends DATA(N-2)
Master sends Acknowledge
SCL stretched by master
Set RBNE and BTC
8) Read DATA(N-1)
7) Set GENSTP
SCL stretched by master
9) Read DATA(N)
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Programming model for DMA mode
As is shown in Programming Model, each time TBE or RBNE is asserted, software should
write or read a byte, this may cause CPU’s high overload. DMA can be used to process TBE
and RBNE flag: each time TBE or RBNE is asserted. DMA does a read or write operation
automatically.
14.3.8. Packet error checking
There is a CRC-8 calculator in I2C block to perform Packet Error Checking for I2C data. The
polynomial of the CRC is x8 + x2 + x + 1 which is compatible with the SMBus protocol. If
enabled by setting PECEN bit, the PEC will calculate all the data transmitted through I2C
including address. I2C is able to send out the PEC value after the last data byte or check the
received PEC value with its calculated PEC using the PECTRANS bit. In DMA mode, the I2C
will send or check PEC value automatically if PECEN bit is set.
14.3.9. SMBus support
The System Management Bus (abbreviated to SMBus or SMB) is a single-ended simple two-
wire bus for the purpose of lightweight communication. Most commonly it is found in computer
motherboards for communication with the power source for ON/OFF instructions.It is derived
from I2C for communication with low-bandwidth devices on a motherboard, especially power
related chips such as a laptop's rechargeable battery subsystem (see Smart Battery Data).
SMBus protocol
Each message transaction on SMBus follows the format of one of the defined SMBus
protocols. The SMBus protocols are a subset of the data transfer formats defined in the I2C
specifications. I2C devices that can be accessed through one of the SMBus protocols are
compatible with the SMBus specifications. I2C devices that do not adhere to these protocols
cannot be accessed by standard methods as defined in the SMBus and Advanced
Configuration and Power Management Interface (abbreviated to ACPI) specifications.
Address resolution protocol
The SMBus uses I2C hardware and I2C hardware addressing, but adds second-level
software for building special systems. Additionally, its specifications include an Address
Resolution Protocol that can make dynamic address allocations. Dynamic reconfiguration of
the hardware and software allow bus devices to be ‘hot-plugged’ and used immediately,
without restarting the system. The devices are recognized automatically and assigned unique
addresses. This advantage results in a plug-and-play user interface. In both those protocols
there is a very useful distinction made between a System Host and all the other devices in
the system that can have the names and functions of masters or slaves.
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Time-out feature
SMBus has a time-out feature which resets devices if a communication takes too long. This
explains the minimum clock frequency of 10 kHz to prevent locking up the bus. I2C can be a
‘DC’ bus, meaning that a slave device stretches the master clock when performing some
routine while the master is accessing it. This will notify to the master that the slave is busy but
does not want to lose the communication. The slave device will allow continuation after its
task is completed. There is no limit in the I2C bus protocol as to how long this delay can be,
whereas for a SMBus system, it would be limited to 35ms. SMBus protocol just assumes that
if something takes too long, then it means that there is a problem on the bus and that all
devices must reset in order to clear this mode. Slave devices are not allowed to hold the clock
low too long.
Packet error checking
SMBus 2.0 and 1.1 allow enabling Packet Error Checking (PEC). In that mode, a PEC (packet
error code) byte is appended at the end of each transaction. The byte is calculated as CRC-
8 checksum, calculated over the entire message including the address and read/write bit. The
polynomial used is x8+x2+x+1 (the CRC-8-ATM HEC algorithm, initialized to zero).
SMBus alert
The SMBus has an extra optional shared interrupt signal called SMBALERT# which can be
used by slaves to tell the host to ask its slaves about events of interest. SMBus also defines
a less common "Host Notify Protocol", providing similar notifications but passing more data
and building on the I2C multi-master mode.
SMBus programming flow
The programming flow for SMBus is similar to normal I2C. In order to use SMBus mode, the
application should configure several SMBus specific registers, response to some SMBus
specific flags and implement the upper protocols described in SMBus specification.
1. Before communication, SMBEN bit in I2C_CTL0 should be set and SMBSEL and ARPEN
bits should be configured to desired value.
2. In order to support ARP protocol (ARPEN=1), the software should response to HSTSMB
flag in SMBus Host Mode (SMBTYPE =1) or DEFSMB flag in SMBus Device Mode, and
implement the function of ARP protocol.
3. In order to support SMBus Alert Mode, the software should response to SMBALTS flag
and implement the related function.
14.3.10. Status, errors and interrupts
There are several status and error flags in I2C, and interrupt may be asserted from these
flags by setting some register bits (refer to I2C register for detail).
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Table 14-2. Event status flags
Event Flag Name
Description
SBSEND
START condition sent (master)
ADDSEND
Address sent or received
ADD10SEND
Header of 10-bit address sent
STPDET
STOP condition detected
BTC
Byte transmission completed
TBE
I2C_DATA is empty when transmitting
RBNE
I2C_DATA is not empty when receiving
Table 14-3. I2C error flags
I2C Error Name
Description
BE
Bus error
LOSTARB
Arbitration lost
OUERR
Over-run or under-run when SCL stretch is
disabled.
AERR
No acknowledge received
PECERR
CRC value doesn’t match
SMBTO
Bus timeout in SMBus mode
SMBALTS
SMBus Alert
14.4. I2C registers
14.4.1. Control register 0 (I2C_CTL0)
Address offset: 0x00
Reset value: 0x0000
This register can be accessed by half-word (16-bit) or word (32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
SRESET
Reserved
SALT
PECTRANS
POAP
ACKEN
STOP
START
DISSTRC
GCEN
PECEN
ARPEN
SMBSEL
Reserved
SMBEN
I2CEN
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
15
SRESET
Software reset I2C, software should wait until the I2C lines are released to reset
the I2C
0: I2C is not under reset
1: I2C is under reset
14
Reserved
Must be kept the reset value
13
SALT
Software can set and clear this bit and hardware can clear this bit.
0: Don’t issue alert through SMBA
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1: Issue alert through SMBA pin
12
PECTRANS
PEC Transfer
Software sets and clears this bit while hardware clears this bit when PEC is
transferred or START/STOP condition detectedor I2CEN=0
0: Don’t transfer PEC value
1: Transfer PEC
11
POAP
Position of ACK/PEC’s meaning
This bit is set and cleared by software and cleared by hardware when I2CEN=0
0: ACKEN bit decides whether to send ACK or not for the current byte that is being
received. PEC bit indicates that PECTRANS is in shift register
1: ACKEN bit decides whether to send ACK or not for the next byte, PECTRANS bit
indicates that the next byte to be received is PEC
10
ACKEN
Whether or not to send an ACK
This bit is set and cleared by software and cleared by hardware when I2CEN=0
0: ACK will not be sent
1: ACK will be sent
9
STOP
Generate a STOP condition on I2C bus
This bit is set and cleared by software and set by hardware when SMBUs timeout
and cleared by hardware when STOP condition detected.
0: STOP will not be sent
1: STOP will be sent
8
START
Generate a START condition on I2C bus
This bit is set and cleared by software and and cleared by hardware when START
condition detected or I2CEN=0
0: START will not be sent
1: START will be sent
7
DISSTRC
Whether to stretch SCL low when data is not ready in slave mode.
This bit is set and cleared by software.
0: SCL Stretching is enabled
1: SCL Stretching is disabled
6
GCEN
Whether or not to response to a General Call (0x00)
0: Slave won’t response to a General Call
1: Slave will response to a General Call
5
PECEN
PEC Calculation Switch
0: PEC Calculation off
1: PEC Calculation on
4
ARPEN
ARP protocol in SMBus switch
0: ARP is disabled
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1: ARP is enabled
3
SMBSEL
SMBusType Selection
0: Device
1: Host
2
Reserved
Must keep the reset value
1
SMBEN
SMBus/I2C mode switch
0: I2C mode
1: SMBus mode
0
I2CEN
I2C peripheral enable
0: I2C is disabled
1: I2C is enabled
14.4.2. Control register 1 (I2C_CTL1)
Address offset: 0x04
Reset value: 0x0000
This register can be accessed by half-word (16-bit) or word (32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
DMALST
DMAON
BUFIE
EVIE
ERRIE
Reserved
I2CCLK[5:0]
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
15:13
Reserved
Must be kept the reset value
12
DMALST
Flag indicating DMA last transfer
0: Next DMA EOT is not the last transfer
1: Next DMA EOT is the last transfer
11
DMAON
DMA mode switch
0: DMA mode disabled
1: DMA mode enabled
10
BUFIE
Buffer interrupt enable
0: No interrupt asserted when TBE = 1 or RBNE = 1
1: Interrupt asserted when TBE = 1 or RBNE = 1 if ITEVTEN=1
9
EVIE
Event interrupt enable
0: Event interrupt disabled
1: Event interrupt enabled, means that interrupt will be generated when SBSEND,
ADDSEND, ADD10SEND, STPDET or BTC flag asserted or TBE=1 or RBNE=1 if
BUFIE=1.
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8
ERRIE
Error interrupt enable
0: Error interrupt disabled
1: Error interrupt enabled, means that interrupt will be generated when BE,
LOSTARB, AERR, OUERR, PECERR, SMBTO or SMBALTS flag asserted.
7:6
Reserved
Must be kept the reset value
5:0
I2CCLK[5:0]
I2C Peripheral clock frequency
I2CCLK[5:0] should be the frequency of input APB clock in MHz which is at least 2.
0h - 1h: Not allowed
2h - 36h: 2 MHz~36MHz
37h - 63h: Not allowed due to the limitation of APB clock
14.4.3. Slave address register 0 (I2C_SADDR0)
Address offset: 0x08
Reset value: 0x0000
This register can be accessed by half-word (16-bit) or word (32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
ADDFORMAT
Reserved
ADDRESS[9:8]
ADDRESS[7:1]
ADDRESS0
rw
rw
rw
rw
Bits
Fields
Descriptions
15
ADDFORMAT
Address mode for the I2C slave
0: 7-bit Address
1: 10-bit Address
14:10
Reserved
Must be kept the reset value
9:8
ADDRESS[9:8]
Highest two bits of a 10-bit address
7:1
ADDRESS[7:1]
7-bit address or bits 7:1 of a 10-bit address
0
ADDRESS0
Bit 0 of a 10-bit address
14.4.4. Slave address register 1 (I2C_SADDR1)
Address offset: 0x0C
Reset value: 0x0000
This register can be accessed by half-word (16-bit) or word (32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
ADDRESS2[7:1]
DUADEN
rw
rw
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Bits
Fields
Descriptions
15:8
Reserved
Must be kept the reset value
7:1
ADDRESS2[7:1]
Second I2C address for the slave in Dual-Address mode
0
DUADEN
Dual-Address mode switch
0: Dual-Address mode disabled
1: Aual-Address mode enabled
14.4.5. Transfer buffer register (I2C_DATA)
Address offset: 0x10
Reset value: 0x0000
This register can be accessed by half-word (16-bit) or word (32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
TRB[7:0]
rw
Bits
Fields
Descriptions
15:8
Reserved
Must be kept the reset value
7:0
TRB[7:0]
Transmission or reception data buffer register
14.4.6. Transfer status register 0 (I2C_STAT0)
Address offset: 0x14
Reset value: 0x0000
This register can be accessed by half-word (16-bit) or word (32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
SMBALTS
SMBTO
Reserved
PECERR
OUERR
AERR
LOSTARB
BE
TBE
RBNE
Reserved
STPDET
ADD10SEND
BTC
ADDSEND
SBSEND
rc_w0
rc_w0
rc_w0
rc_w0
rc_w0
rc_w0
rc_w0
r
r
r
r
r
r
r
Bits
Fields
Descriptions
15
SMBALTS
SMBus Alert status
This bit is set by hardware and cleared by writing 0.
0: SMBA pin not pulled down (device mode) or no Alert detected (host mode)
1: SMBA pin pulled down (device mode) or Alert detected (host mode)
14
SMBTO
Timeout signal in SMBus mode
This bit is set by hardware and cleared by writing 0.
0: No timeout error
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1: Timeout event occurs (SCL is low for 25 ms)
13
Reserved
Must keep the reset value
12
PECERR
PEC error when receiving data
This bit is set by hardware and cleared by writing 0.
0: Received PEC and calculated PEC match
1: Received PEC and calculated PEC don’t match, I2C will send NACK careless of
ACKEN bit.
11
OUERR
Over-run or under-run situation occurs in slave mode, when SCL stretching is
disabled. In slave receiving mode, if the last byte in I2C_DATA is not read out while
the following byte is already received, over-run occurs. In slave transmitting mode,
if the current byte is already sent out, while the I2C_DATA is still empty, under-run
occurs.
This bit is set by hardware and cleared by writing 0.
0: No over-run or under-run occurs
1: Over-run or under-run occurs
10
AERR
Acknowledge Error
This bit is set by hardware and cleared by writing 0.
0: No Acknowledge Error
1: Acknowledge Error
9
LOSTARB
Arbitration Lost in master mode
This bit is set by hardware and cleared by writing 0.
0: No Arbitration Lost
1: Arbitration Lost occurs and the I2C block changes back to slave mode.
8
BE
A bus error occurs indication an unexpected START or STOP condition on I2C bus
This bit is set by hardware and cleared by writing 0.
0: No bus error
1: A bus error detected
7
TBE
I2C_DATA is Empty during transmitting
This bit is set by hardware after it moves a byte from I2C_DATA to shift register
and cleared by writing a byte to I2C_DATA. If both the shift register and I2C_DATA
are empty, writing I2C_DATA won’t clear TBE (refer to Programming Model for
detail).
0: I2C_DATA is not empty
1: I2C_DATA is empty, software can write
6
RBNE
TRBR is not Empty during receiving
This bit is set by hardware after it moves a byte from shift register to I2C_DATA
and cleared by reading it. If both BTC and RBNE are asserted, reading I2C_DATA
won’t clear RBNE because the shift register’s byte is moved to I2C_DATA
immediately.
0: TRBR is empty
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1: TRBR is not empty, software can read
5
Reserved
Must be kept the reset value
4
STPDET
STOP condition detected in slave mode
This bit is set by hardware and cleared by reading I2C_STAT0 and then writing
I2C_CTL0
0: STOP condition not detected in slave mode
1: STOP condition detected in slave mode
3
ADD10SEND
Header of 10-bit address is sent in master mode
This bit is set by hardware and cleared by reading I2C_STAT0 and writing
I2C_DATA.
0: No header of 10-bit address sent in master mode
1: Header of 10-bit address is sent in master mode
2
BTC
Byte transmission completed.
If a byte is already received in shift register but I2C_DATA is still full in receiving
mode or a byte is already sent out from shift register but I2C_DATA is still empty in
transmitting mode, the BTC flag is asserted if SCL stretching enabled.
This bit is set by hardware and cleared by reading I2C_STAT0 and reading or
writing I2C_DATA.
0: BTC not asserted
1: BTC asserted
1
ADDSEND
Address is sent in master mode or received and matches in slave mode.
This bit is set by hardware and cleared by reading I2C_STAT0 and reading
I2C_STAT1.
0: No address sent or received
1: Address sent out in master mode or a matched address is received in salve
mode
0
SBSEND
START condition sent out in master mode
This bit is set by hardware and cleared by reading I2C_STAT0 and writing
I2C_DATA
0: No START condition sent
1: START condition sent
14.4.7. Transfer status register 1 (I2C_STAT1)
Address offset: 0x18
Reset value: 0x0000
This register can be accessed by half-word (16-bit) or word (32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
ECV[7:0]
DUMODF
HSTSMB
DEFSMB
RXGC
Reserved
TRS
I2CBSY
MASTER
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r
r
r
r
r
r
r
r
Bits
Fields
Descriptions
15:8
ECV[7:0]
Packet Error Checking Value that calculated by hardware when PEC is enabled.
7
DUMODF
Dual Flag in slave mode indicating which address is matched in Dual-Address
mode
This bit is cleared by hardware after a STOP or a START condition or I2CEN=0
0: SADDR0 address matches
1: SADDR1 address matches
6
HSTSMB
SMBus Host Header detected in slave mode
This bit is cleared by hardware after a STOP or a START condition or I2CEN=0
0: No SMBus Host Header detected
1: SMBus Host Header detected
5
DEFSMB
SMBus host header in slave mode
This bit is cleared by hardware after a STOP or a START condition or I2CEN=0.
0: SMBus Device has no default address
1: Received a default address for SMBus Device
4
RXGC
General call address (00h) received.
This bit is cleared by hardware after a STOP or a START condition or I2CEN=0.
0: No general call address (00h) received
1: General call address (00h) received
3
Reserved
Must be kept the reset value
2
TRS
Whether the I2C is a transmitter or a receiver
This bit is cleared by hardware after a STOP or a START condition or I2CEN=0 or
LOSTARB.
0: Receiver
1: Transmitter
1
I2CBSY
Busy flag
This bit is cleared by hardware after a STOP condition
0: No I2C communication.
1: I2C communication active.
0
MASTER
A flag indicating whether I2C block is in master or slave mode.
This bit is cleared by hardware after a STOP or a START condition or I2CEN=0 or
LOSTARB.
0: Slave mode
1: Master mode
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14.4.8. Clock configure register (I2C_CKCFG)
Address offset: 0x1C
Reset value: 0x0000
This register can be accessed by half-word (16-bit) or word (32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
FAST
DTCY
Reserved
CLKC[11:0]
rw
rw
rw
Bits
Fields
Descriptions
15
FAST
I2C speed selection in master mode
0: Standard speed
1: Fast speed
14
DTCY
Duty cycle in fast mode
0:   
1:  
13:12
Reserved
Must be kept the reset value
11:0
CLKC[11:0]
I2C Clock control in master mode
In standard speed mode:     
In fast speed mode if DTCY=0:
   ,    
In fast speed mode if DTCY=1:
    ,   
14.4.9. Rise time register (I2C_RT)
Address offset: 0x20
Reset value: 0x0002
This register can be accessed by half-word (16-bit) or word (32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
RISETIME[5:0]
rw
Bits
Fields
Descriptions
15:6
Reserved
Must be kept the reset value
5:0
RISETIME[5:0]
Maximum rise time in master mode
The RISETIME value should be the maximum SCL rise time incremented by 1.
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14.4.10. SAM control and status register (I2C_SAMCS) of GD32F170xx and
GD32F190xx devices
Address offset: 0x80
Reset value: 0x0000
This register can be accessed by half-word (16-bit) or word (32-bit)
15
14
13
12
11 10
9
8
7
6
5
4
3 2
1
0
RFR
RFF
TFR
TFF
Reserved
RXF
TXF
RFRIE
RFFIE
TFRIE
TFFIE
Reserved
STOE
N
SAME
N
r_w0
r_w0
r_w0
r_w0
r
r
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
15
RFR
Rxframe rise flag, cleared by software write 0
14
RFF
Rxframe fall flag, cleared by software write 0
13
TFR
Txframe rise flag, cleared by software write 0
12
TFF
Txframe fall flag, cleared by software write 0
11:10
Reserved
Must be kept the reset value
9
RXF
Level of Rxframe signal
8
TXF
Level of Txframe signal
7
RFRIE
Rxframe rise interrupt enable
0: Disable
1: Enable
6
RFFIE
Rxframe fall interrupt enable
0: Disable
1: Enable
5
TFRIE
Txframe rise interrupt enable
0: Disable
1: Enable
4
TFFIE
Txframe fall interrupt enable
0: Disable
1: Enable
3:2
Reserved
Must be kept the reset value
1
STOEN
SAM_V interface timeout detect enable
0: Disable
1: Enable
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0
SAMEN
SAM_V interface enable
0: Disable
1: Enable
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15. Serial peripheral interface/Inter-IC sound(SPI/I2S)
15.1. Introduction
The SPI/I2S module can communicate with external devices using the SPI protocol or the I2S
audio protocol.
The Serial Peripheral Interface (SPI) provides a SPI protocol data transmit and receive
function in both master and slave mode. For GD32F130xx and GD32F150xx devices, the SPI
Interface supports single wire configuration in both master and slave mode. But for
GD32F170xx and GD32F190xx devices, the SPI Interface also supports quad wire
configuration in master mode except supporting single wire configuration. In single wire
configuration, the SPI interface uses 4 pins, among which are the serial data input and output
lines MISO and MOSI, the clock line (SCK), and the slave select line (NSS). In quad wire
configuration, SPI uses 6 pins: MOSI, MISO, IO2, IO3, SCK and NSS. One SPI device acts
as a master which controls the data flow using the NSS and SCK signals to indicate the start
of the data communication and the data sampling rate. To receive a data byte, the streamed
data bits are latched on a specific clock edge and stored in the Data transfer register. Data
transmission is carried in a similar way but with a reverse sequence. The configuration fault
detection provides a capability for multi-master applications. The SPI interface may be used
for a variety of purposes, including simplex synchronous transfers on two lines with a possible
bidirectional data line or reliable communication using CRC checking.
The inter-IC sound function supports four audio standards, including I2S Phillips standard,
MSB justified standard, LSB justified standard, and PCM standard. It can operate in four
modes, including master transmission mode, master reception mode, slave transmission
mode, and slave reception mode.
15.2. Main features
15.2.1. SPI features
Master or slave operation
Programmable clock bit rate
Programmable clock polarity and phase
Separate transmit and receive buffer, 16 bits wide
Programmable data frame size, 8 or 16 bits
Programmable data order, transmit MSB-first or LSB-first
Hardware CRC calculation and transmit automatic CRC error checking
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Full-duplex synchronous transfers on three lines
Simplex synchronous transfers on two lines
NSS work in software mode or hardware mode for both master and slave
SPI bus busy status flag
Transmission and reception flags with interrupt capability
Master configuration fault, overrun and CRC error flags with interrupt capability
Transmission and reception by DMA capability
For GD32F170xx and GD32F190xx devices, additional features are shown below.
Quad wire configuration available in master mode(SPI1)
15.2.2. I2S features
Supported I2S standards:
I2S Phillips standard
MSB justified standard
LSB justified standard
PCM standard (both short and long frame synchronization mode)
Supported operation modes:
Master transmission
Master reception
Slave transmission
Slave reception
The data length can be 16 bits, 24 bits or 32 bits
The channel length can be 16 bits or 32 bits
16-bit shift register for transmission and reception
Data direction is always MSB first
8-bit programmable linear prescaler to reach accurate audio sample frequencies from 8
kHz to 192 kHz
Programmable idle state clock polarity
Master clock can be output to drive an external audio component
Error flags including the transmission underrun error flag (TXURERR) and the reception
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overrun error flag (RXORERR)
DMA capability for both transmission and reception
15.3. SPI function description
15.3.1. Pin configuration (Single wire, default)
The SPI is connected to external devices through 2-4 pins in different modes:
MISO: This pin is used to receive data in master mode (Master In) or transmit data in
slave mode (Slave Out).
MOSI: This pin is used to transmit data in master mode (Master Out) or receive data in
slave mode (Slave In).
SCK: This pin is used to output clock in master mode or receive clock in slave mode.
NSS: In hardware mode (SWNSSEN bit is cleared), the NSS pin can be used as an input.
The NSS pin should be driven high in master mode or driven low in slave mode. It was
a fault if the NSS pin is driven low in master mode, CONFERR bit will be set and
MSTMOD will be cleared by hardware. The NSS pin is driven high in slave mode which
means the chip is not selected, the SPI would not work until the NSS pin is driven low.
In software mode (SWNSSEN bit is set), the SWNSS bit replaces the function of the NSS
pin, the NSS pin can be used as a standard IO ports. In addition, the NSS pin can be
used as an output in master mode when NSSDRV is set, the NSS pin will be driven low
when SPI starts.
Typical interconnections between a single master and a single slave:
Figure 15-1. Single master/ single slave application
The MOSI pins are connected, the MISO pins are connected and the SCK pins are connected.
MISO
MISO
NSS
MOSI
MOSI
VDD
NSS
SCK
SCK
PCLK
Master
8/16-bit shift register
Transmit buffer
Receive buffer
PSC
Slaver
8/16-bit shift register
Transmit buffer
Receive buffer
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Data is transferred from master to slave by MOSI line and transferred from slave to master
by MISO line. The clock is created in master and transferred to slave by SCK. In hardware
mode (SWNSSEN bit is cleared), the NSS is driven high in master mode or driven low in slave
mode; in software mode (SWNSSEN bit is set), the NSS pin is not used.
The master device controls the communication by the clock. When the master device
transmits data to the slave device via MOSI pin, it sends clock to the slave device at same
time via SCK pin, the slave receives data via MOSI pin and transmits data via MISO pin
according to the clock.
The NSS pin can be used in software mode or hardware mode by the SWNSSEN bit in the
SPI_CTL0 register.
Hardware NSS mode (SWNSSEN = 0)
Depending on the NSSDRV bit in SPI_CTL1 register, the NSS pin can be used as input
or output (only in master mode).
– NSS output enabled (SWNSSEN = 0, NSSDRV = 1)
This configuration is used only in master mode. The NSS signal is driven low when
the master starts the communication (start to transmit clock) and is kept low until
the SPI is disabled.
– NSS output disabled (SWNSSEN = 0, NSSDRV = 0)
The NSS pin is used as input. In master mode, the NSS pin should be driven high.
In slave mode, the NSS pin acts as a chip select, the slave is selected when NSS
is low and deselected when NSS high.
Software NSS mode (SWNSSEN = 1)
The SWNSS bit in SPI_CTL0 replace the function of the NSS pin, in master mode, the
SWNSS bit should be set. In slave mode, the slave is selected when SWNSS is
cleared and deselected when SWNSS is set. The NSS pin is not used in SPI
communication.
Clock phase and clock polarity
Using the CKPL and CKPH bits in SPI_CTL0 register, four types of the timing relationship can
be configured. The CKPL bit controls the steady state value of the clock. If the CKPL is cleared,
the SCK pin is low when idle. If the CKPL is set, the SCK pin is high when idle.
The CKPH determines the timing of capturing the data. If the CKPH is cleared, capturing the
first data at the first edge on the SCK pin. If the CKPH is set, capturing the first data at the
second edge on the SCK pin.
The following figure shows an SPI transfer with the four types of timing relationship:
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Figure 15-2. SPI data clock timing diagram
Data frame format
Data can be shifted out either MSB-first or LSB-first depending on the value of the LF bit in
the SPI_CTL0 Register.
Depending on the LF bit in SPI_CTL0 register, the MSB (LF=0) or the LSB (LF=1) will be sent
out at first. And the length of data is 8 bits or 16 bits depending on the FF16 bit in the
SPI_CTL0 register.
15.3.2. Pin configuration (Quad wire) for GD32F170xx and GD32F190xx devices
SPI is in single wire configuration by default and enters into quad wire mode after QMOD bit
in SPI_QCTL register is set (only available in SPI1).
The SPI is connected to external devices through 6 pins in quad wire configuration:
MOSI: This pin is used to transmit data in quad write mode and receive data in quad
read mode.
Capture
NSS (SLAVE)
CKPH=0
CKPL= 1
CKPL= 0
MISO
MOSI
CKPH=1
CKPL= 1
CKPL= 0
MISO
MOSI
Capture
NSS (SLAVE)
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MISO: This pin is used to transmit data in quad write mode and receive data in quad
read mode.
IO2: This pin is used to transmit data in quad write mode and receive data in quad read
mode.
IO3: This pin is used to transmit data in quad write mode and receive data in quad read
mode.
SCK: The configuration and behavior of SCK pin is the same as single wire mode except
that there are only 2 clock cycles per data frame in quad wire configuration.
Data frame format: The frame length is fixed to 8 bits in quad wire mode, as shown below.
Figure 15-3. SPI data clock timing diagram in quad wire mode (CKPL=1, CKPH=1)
D[5]
D[4]
D[6]
D[7]
D[0]
D[1]
D[2]
D[3]
D[5]
D[4]
D[6]
D[7]
D[0]
D[1]
D[2]
D[3]
SCK
MOSI
MISO
IO2
IO3
NSS(slave)
Capture
15.3.3. SPI slave mode
In slave mode, the serial clock is received from master device, the PSC[2:0] bits in the
SPI_CTL0 register are useless. The communication is controlled by the master device and
the slave should be enabled before the master sends the clock.
SPI slave mode configuration steps:
1. Program data format (FF16 bit in the SPI_CTL0 register).
2. Program the timing relationships (CKPL and CKPH bits in the SPI_CTL0 register). They
must be configured in the same way as the master device.
3. Program the frame format (LF bit in the SPI_CTL0 register), it must be same as the
master device.
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4. Program the NSS mode (SWNSSEN bit in the SPI_CTL0 register). In hardware mode
(SWNSSEN=0), the NSS pin must be connected to a low level signal during transmit
sequence. In software mode (SWNSSEN=1), the SWNSS bit in the SPI_CTL0 register
must be cleared during transmit sequence.
5. Set the slave mode (Clear the MSTMOD bit). Enable the SPI (set the SPIEN bit).
Transmit sequence
The slave transmit begins when the slave receives the clock via the SCK pin, the LSB or MSB
transmit on its MOSI pin, the other bits are loaded from transmit buffer to shift-register. The
TBE bit is set and the software writes the second data to the transmit buffer if it is necessary.
The hardware transmits the bits in the shift-register according the clock received.
Receive sequence
After the last sampling clock edge, data transfer is complete, the data in shift register is copied
to receive buffer and the RBNE bit in SPI_STAT register is set. Reading SPI_DATA returns
the data in receive buffer and the RBNE bit is cleared by reading the SPI_DATA register.
15.3.4. SPI master mode
In the master configuration, the serial clock is generated on the SCK pin.
In master mode, the serial clock is generated by the PCLK (PCLK2 for SPI0 or PCLK1 for
SPI1), the PSC[2:0] is the baud rate.
SPI master mode configuration steps:
1. Program the PSC[2:0] bits to define the baud rate.
2. Program data format (FF16 bit in the SPI_CTL0 register).
3. Program the timing relationships (CKPL and CKPH bits in the SPI_CTL0 register). They
must be configured in the same way as the slave device.
4. Program the frame format (LF bit in the SPI_CTL0 register), it must be same as the slave
device.
5. Program the NSS mode (SWNSSEN bit in the SPI_CTL0 register). If the NSS pin is used
as input, in hardware mode (SWNSSEN=0), the NSS pin must be connected to a high
level signal. In software mode (SWNSSEN=1), the SWNSS bit in the SPI_CTL0 register
must be set. If the NSS pin is used as output, the NSSDRV bit should be set, and the
NSS pin will be driven low when the transfer begins.
6. Set the master mode (Set the MSTMOD bit). Enable the SPI (set the SPIEN bit).
Transmit sequence
The master transmit begins when a data is written in the transmit buffer, the LSB or MSB
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transmit on its MOSI pin, the other bits are loaded from transmit buffer to shift-register. The
TBE bit is set after the data is loaded from transmit buffer to shift-register. A continuous data
can be transmitted if the data is put in the transmit buffer. Write SPI_DATA register when the
TBE bit is set.
Receive sequence
After the last sampling clock edge, data transfer is complete, the data in shift register is copied
to receive buffer and the RBNE bit in SPI_STAT register is set. Reading SPI_DATA returns
the data in receive buffer and the RBNE bit is cleared by reading the SPI_DATA register.
15.3.5. SPI quad wire operation in master mode for GD32F170xx and
GD32F190xx devices
The SPI quad wire mode is designed to control quad SPI flash, including but not limited to
GD25QXX serials flash chip.
In order to enter quad wire mode, the software should first verify that the TBE bit is set and
TRANS bit is cleared, and then set QMOD bit in SPI_QCTL register. In quad wire mode,
BDEN, BDOEN, CRCERRN, CRCNT, FF16, RO and LF in SPI_CTL0 register should be kept
cleared and MSTMOD should be set to ensure that SPI is in master mode. SPIEN, PSC,
CKPL and CKPH should be configured as desired.
There are 2 operation modes in quad wire configuration: quad write and quad read, decided
by QRD bit in SPI_QCTL register.
Quad write operation
SPI works in quad write mode when QMOD is set and QRD is cleared in SPI_QCTL register.
In this mode, MOSI, MISO, IO2 and IO3 are all used as output pins. SPI begins to generate
clock on SCK line and transmit data on MOSI, MISO, IO2 and IO3 as soon as TBE is cleared
(SPI_DATA not empty) and SPIEN is set. Once SPI starts transmission, it always checks
SPIEN and TBE status at the end of a frame and stops when condition not met.
The operation flow for transmitting in quad mode:
1. Configure clock presales, clock polarity, phase, etc in SPI_CTL0 and SPI_CTL1 based
on your application requirements.
2. Set QMOD bit in SPI_QCTL register and then enable SPI by setting SPIEN in SPI_CTL0.
3. Write the byte to SPI_DATA register and the TBE will be cleared.
4. Wait until TBE be set by hardware again before writing the next byte.
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D1[5]
D1[4]
D1[6]
D1[7]
D1[0]
D1[1]
D1[2]
D1[3]
SCK
MOSI
MISO
IO2
IO3
TBE
D2[4]
D2[6]
D2[7]
D2[0]
D2[1]
D2[2]
D2[3]
D2[5]
Software Write SPI_DATA Hadware Set TBE again
Quad read operation
SPI works in quad read mode when QMOD and QRD both set in SPI_QCTL register. In this
mode, MOSI, MISO, IO2 and IO3 are all used as input pins. SPI begins to generate clock on
SCK line as soon as TBE is cleared (SPI_DATA not empty) and SPIEN is set. Once SPI starts
transmission, it always checks SPIEN and TBE status at the end of a frame and stops when
condition not met. So, software should always write dummy data into SPI_DATA to make SPI
generate SCK and receive data.
The operation flow for receiving in quad mode:
1. Configure clock presales, clock polarity, phase, etc in SPI_CTL0 and SPI_CTL1 based
on your application requirements.
2. Set QMOD and QRD bits in SPI_QCTL register and then enable SPI by setting SPIEN
in SPI_CTL0.
3. Write an arbitrary byte (for example, 0xFF) to SPI_DATA register.
4. Wait the RBNE flag set and read SPI_DATA to get the received byte.
5. Write an arbitrary byte (for example, 0xFF) to SPI_DATA to receive the next byte.
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D1[5]
D1[4]
D1[6]
D1[7]
D1[0]
D1[1]
D1[2]
D1[3]
SCK
MOSI
MISO
IO2
IO3
TBE
D2[4]
D2[6]
D2[7]
D2[0]
D2[1]
D2[2]
D2[3]
D2[5]
Software Write
SPI_DATA
Hadware Set TBE
RBNE
Software Read
SPI_DATA
Software Write
SPI_DATA
Leave quad wire mode or disable SPI
Before leaving quad wire mode or disabling SPI, software should first check that TBE bit is
set and TRANS bit is cleared, then clear the QMOD bit in SPI_QCTL register or SPIEN bit in
SPI_CTL0 register.
15.3.6. SPI simplex communication
The SPI is able to work in simplex mode in 2 configurations.
1. Set the BDEN bit in the SPI_CTL0 register. The clock is transmitted from the SCK pin of
master to the SCK pin of slave. The data is transmitted between the MOSI pin of the
master and the MISO pin of the slave. The transfer direction is defined by the BDOEN
bit in the SPI_CTL0 register, the BDOEN bit in master and slave must be different. If the
BDOEN is set in master and cleared in slave, the data is transmitted from master to slave.
If the BDOEN is cleared in master and set in slave, the data is transmitted from slave to
master.
2. BDEN is cleared, the RO bit in master and in slave should be different in simplex
communication. If the RO bit is cleared in master and set in slave, the data is transmitted
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from master to slave, the MOSI pin of master outputs the data and the MOSI pin of slave
receives the data, the MISO pins are not used. If the RO bit is set in master and cleared
in slave, the data is transmitted from slave to master, the MISO pin of slave outputs the
data and the MISO pin of master receives the data, the MOSI pins are not used. Anyway
the clock is generated in master and transmitted to slave by SCK pins.
In simplex communication, if the master is configured in receive-only mode and the slave is
configured in transmit-only mode, the master starts receiving data immediately when the SPI
is enable. The slave should get ready before the master enables the SPI, and write data in
transmit buffer in a limited time. The master should disable the SPI (clear the SPIEN bit) after
the last second data is received; the last data is being transmitted at that time, and the SPI
will be disabled by hardware after the last data received.
15.3.7. Data Rx and Tx procedures
There are two buffers for each SPI module, transmit buffer and receive buffer, a write access
to the SPI_DATA stores the data into the transmit buffer and a read access to the SPI_DATA
returns the data in the receive buffer.
When the previous data is transmitted over, the data in the transmit buffer is copied to the
shift register, and the TBE bit is set by hardware, then the software can write the next data to
the transmit buffer by writing it to the SPI_DATA register if it is necessary, an interrupt is
generated when the TBE is set if the TBEIE bit in the SPI_CTL1 register is set. Writing the
SPI_DATA register can clear the TBE bit. Writing the SPI_DATA register when the TBE bit is
cleared will cover the data stored in the transmit buffer.
When the last bit of one data is captured on the sampling clock edge, the data is received
and stored in shift register, then the hardware copies the data in shift register to the receive
buffer and sets the RBNE bit. It’s ready to be read by software. An interrupt is generated when
the RBNE is set if the RBNEIE bit in the SPI_CTL1 register is set. Reading the SPI_DATA
register can clear the RBNE bit. If one data is received when the RBNE is set (the last data
have not be read), the RXORERR bit is set to indicate that was fault.
15.3.8. CRC calculation
CRC calculation increases communication reliability. Two CRC calculators are implemented
for transmitted data and received data. The calculators calculate the CRC value serially on
each bit. The polynomial used in calculation is programmable and stored in SPI_CRCPOLY
register.
CRC calculation is enabled by setting the CRCEN bit in the SPI_CTL0 register. In full-duplex
or transmit-only mode, the software should set the CRCNT bit immediately after the last data
is written to the SPI_DATA, last the SPI_TCRC value will be transmitted after the last data. If
the data is transmitted by DMA, the SPI_TCRC value is transmitted by hardware and the
CRCNT is not used. When the SPI_TCRC value is being transmitted, the data received is
considered to be the CRC value of the received data, the calculator is switched off and the
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data is compared with the SPI_RCRC, the CRCERR is set if they are different.
In receive-only mode, the software should write the CRCNT bit after the second last data has
been received (The last data is being received at that time). The CRC value of the received
data is received after the last data and is compared with the SPI_RCRC, the CRCERR is set
if they are different.
The CRC value is transmitted only when the transmit buffer is empty. During CRC
transmission, the CRC calculator is switched off.
SPI communication using the CRC:
1. Program the CKPL, CKPH, LF, PSC, SWNSSEN, SWNSS and MSTMOD values.
2. Program the polynomial in the SPI_CRCPOLY register.
3. Enable the CRC calculation by setting the CRCEN bit in the SPI_CTL0 register.
4. Enable the SPI by setting the SPIEN bit in the SPI_CTL0 register.
5. Start the communication.
6. In full-duplex or transmit-only mode, set the CRCNT bit immediately after the last data is
written to the SPI_DATA. In receive-only mode, set the bit CRCNT after the reception of
the second to last data. CRC calculation is switched off during the CRC transfer.
7. The SPI transfers the CRC value after the last data. The received CRC value is
compared with the SPI_RCRC, the CRCERR is set if they are different.
If the CRCEN is set in slave mode, CRC calculator is still work even if the NSS pin is pulled
high. The CRC value should be cleared on both master and slave sides in order to
resynchronize the master and slave for their respective CRC calculation. The CRC value
(SPI_RCRC and SPI_TCRC) is cleared when the SPIEN bit or the CRCEN is cleared.
15.3.9. Status flags and error flags
Status flags
Transmit buffer empty flag (TBE)
This bit is set when the transmit buffer is empty, the software can write the next data to the
transmit buffer by writing it to the SPI_DATA register. If the TBEIE bit is set, an interrupt is
generated when TBE is set. The TBE bit is cleared by writing it to the SPI_DATA register.
Receive buffer not empty flag (RBNE)
This bit is set when receive buffer is not empty, one data is received and stored in the receive
buffer, and software can read the data by reading the SPI_DATA register. If the RBNEIE bit is
set, an interrupt is generated when RBNE is set. The RBNE bit is cleared by reading the
SPI_DATA register.
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SPI Transmitting On-Going flag (TRANS)
This TRANS flag is set and cleared by hardware. It indicates the state of the communication
layer of the SPI. The TRANS flag is useful to detect the end of a transfer if the software wants
to disable the SPI. This avoids corrupting the last transfer. For this, the procedure described
below must be strictly respected.
The TRANS bit is set when a transfer starts, except in bidirectional receive-only mode of
master device (MSTMOD=1 and BDEN=1 and BDOEN=0). It is cleared when the SPI is
disabled or a configuration fault (CONFERR=1) occurs. When communication is not
continuous, TRANS flag is low between each communication. When communication is
continuous, TRANS flag is low between each communication in slave mode and kept high
during all the transfers in master mode.
Error flags
Configuration Fault Error (CONFERR)
In NSS hardware mode and the NSSDRV is not enable, the CONFERR is set when the NSS
pin is pulled low. In NSS software mode, the CONFERR is set when the SWNSS bit is low.
When the CONFERR is set, an interrupt is generated if the ERRIE bit is set; the SPIEN bit
and the MSTMOD bit are cleared by hardware, the SPI is disabled and the device is forced
into slave mode.
The CONFERR bit is cleared by the following software sequence:
1. Read from or write to the SPI_STAT register.
2. Write to the SPI_CTL0 register.
The SPIEN and MSTMOD bits are in write protection until the CONFERR is cleared. The
CONFERR bit of the slave cannot be set. In a multi-master configuration, the device can be
in slave mode with CONFERR bit set, which means there might have been a multi-master
conflict for system control.
Rx Overrun Error (RXORERR)
The RXORERR bit is set if a data is received when the RBNE is set. That means, the last
data has not be read out and the new data is received. The receive buffer contents will be
cover with the newly received data, and the last data is lost. An interrupt is generated when
the RXORERR bit is set if the ERRIE bit is set.
The RXORERR bit is cleared by the following software sequence: a read access to SPI_DATA
register, then a read access to SPI_STAT register.
CRC error (CRCERR)
When the CRCEN bit is set, the CRC calculation result of the received data in the SPI_RCRC
register is compared with the received CRC value after the last data, the CRCERR is set
when they are different. Clear the CRCERR bit by writing 0 to this bit, write 1 to this bit has
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no effect.
15.3.10. Disabling the SPI
When a transfer is finished, the software stops the SPI by clearing the SPIEN bit. In some
configurations, the last transfer is ongoing after the SPIEN is cleared. To avoid corrupting the
last transfer, follow the steps below:
Full-duplex mode
1. Wait until RBNE=1 to receive the last data
2. Wait until TBE=1
3. Wait until TRANS=0
4. Disable the SPI (SPIEN=0), enter the Halt mode or disable the peripheral clock
Transmit-only mode
1. The last data is written into the SPI_DATA register
2. Wait until TBE=1
3. Wait until TRANS=0
4. Disable the SPI (SPIEN=0), enter the Halt mode or disable the peripheral clock
Receive-only mode of master
1. Wait for the second last RBNE=1
2. Wait for one SPI clock cycle (using a software loop) before disabling the SPI (SPIEN=0)
3. Wait for the last RBNE=1 before entering the Halt mode or disabling the peripheral clock
Receive-only mode of slave
1. The SPI can be disabled (write SPIEN=0) at any time, the SPI is effectively disabled after
the current transfer complete
2. Wait until TRANS = 0 then entering the Halt mode or disabling the peripheral clock.
15.3.11. DMA requests
Using DMA to transmit or receive data will let the SPI operate at its maximum speed. Read
and write SPI_DATA is fast enough and it’s no interstice between data that will be transmitted.
A DMA access is enabled if the DMATEN bit or the DMAREN bit in the SPI_CTL1 register is
set. When the TBE is set, a DMA request is issued in transmit channel of DMA, the TBE bit is
cleared after the DMA writes a data to SPI_DATA register. When the RBNE is set, a DMA
request is issued in receive channel of DMA, the RBNE bit is cleared after the DMA reads a
data from SPI_DATA register.
When the SPI is only used for transmitting data, it is possible to enable the SPI Tx DMA
channel only. In this case, because the data received are not read, the RXORERR flag is set.
When the SPI is only used for receiving data, it is possible to enable the SPI Rx DMA channel
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only.
In transmission mode, when all the data to be transmitted has been written by the DMA (flag
FTFIF is set in the DMA_INTF register), the TRANS flag can be monitored to ensure that the
SPI communication is complete. Before disabling the SPI or entering the halt mode, it is
required to avoid corrupting the last transmission. The software must first wait until TBE=1
and then until TRANS=0.
Figure 15-4. Transmission using DMA
Figure 15-5. Reception using DMA
If the CRCEN bit is set when using DMA in SPI communication, the CRC value transmitted
and received after the last data are automatic. The CRCNT is no useful. The CRC value in
receive buffer should be read to clear the RBNE bit.
15.3.12. SPI interrupts
Table 15-1. SPI interrupt requests
Interrupt event
Event flag
Enable Control bit
Transmit buffer empty
TBE
TBEIE
Clock
Transmit
TBE
DMA request
DMA write
TX buffer
D1
D2
D3
DMA TCIF
TRANS
Clock
Receive
RBNE
DMA request
DMA read
RX buffer
DMA TCIF
D1
D3
D2
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Interrupt event
Event flag
Enable Control bit
Receive buffer not empty
RBNE
RBNEIE
Configuration Fault Error
CONFERR
ERRIE
Rx Overrun Error
RXORERR
CRC error
CRCERR
15.4. I2S function description
15.4.1. General description
The block diagram of I2S is shown in the following figure.
Figure 15-6. I2S block diagram
Clock Generator
SPI_MOSI /
I2S_SD
SPI_NSS /
I2S_WS
SPI_SCK /
I2S_CK
SPI_MISO /
I2S_MCK
Master Control Logic
Slave Control Logic
TX Buffer
Shift Register
RX Buffer
Control
Registers
16
bits
SYSCLK
16
bits
LSBMSB
PAD
PAD
O
I
O
I
PAD
O
I
PAD
O
I
APB
The I2S shares the same pins, flags, interrupts, data buffers, and shift register with SPI. When
the I2SSEL bit in the SPI_I2SCTL register is set, the resources are occupied by I2S. Or, they
are used by SPI.
There are four pins on the I2S interface, including I2S_CK, I2S_WS, I2S_SD, and I2S_MCK.
I2S_CK is the serial clock signal, which shares the same pin with SPI_SCK. I2S_WS is the
data control signal, which shares the same pin with SPI_NSS. I2S_SD is the serial data signal,
which shares the same pin with SPI_MOSI. I2S_MCK is the master clock signal, which shares
the same pin with SPI_MISO. I2S_MCK is an optional signal for I2S interface. It produces a
frequency rate equal to 256 x Fs, where Fs is the audio sampling frequency.
There are five sub modules to support I2S function, including control registers, clock generator,
master control logic, slave control logic and shift register. All the user configuration registers
are implemented in the control registers module, including the TX buffer and RX buffer. The
clock generator is used to produce I2S communication clock in master mode. The master
control logic is implemented to generate the I2S_WS signal and control the communication
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in master mode. The slave control logic is implemented to control the communication in slave
mode according to the received I2SCK and I2S_WS. The shift register handles the serial data
transmission and reception on I2S_SD.
15.4.2. Supported audio standards
The I2S audio standard is selected by the I2SSTD bits in the SPI_I2SCTL register. Four audio
standards are supported, including I2S Phillips standard, MSB justified standard, LSB justified
standard, and PCM standard. All standards except PCM handle audio data time-multiplexed
on two channels (the left channel and the right channel). For these standards, the I2S_WS
signal indicates the channel side. For PCM standard, the I2S_WS signal indicates frame
synchronization information.
The data length and the channel length are configured by the DTLEN bits and CHLEN bit in
the SPI_I2SCTL register. Since the channel length must be greater than or equal to the data
length, four packet types are available. They are 16-bit data packed in 16-bit frame, 16-bit
data packed in 32-bit frame, 24-bit data packed in 32-bit frame, and 32-bit data packed in 32-
bit frame. The data buffer for transmission and reception is 16-bit wide. In the case that the
data length is 24 bits or 32 bits, two write or read operations to or from the SPI_DATA register
are needed to complete a frame. In the case that the data length is 16 bits, only one write or
read operation to or from the SPI_DATA register is needed to complete a frame. When using
16-bit data packed in 32-bit frame, 16-bit 0 is inserted by hardware automatically to extend
the data to 32-bit format.
For all standards and packet types, the most significant bit is always sent first. For all
standards based on two channels time-multiplexed, the channel left is always sent first
followed by the channel right.
I2S Phillips standard
For I2S Phillips standard, I2S_WS and I2S_SD are updated on the falling edge of I2S_CK.
The timing diagrams for each configuration are shown below.
Figure 15-7. I2S Phillips standard timing diagram (DTLEN=00, CHLEN=0, CKPL=0)
Figure 15-8. I2S Phillips standard timing diagram (DTLEN=00, CHLEN=0, CKPL=1)
When the packet type is 16-bit data packed in 16-bit frame, only one write or read operation
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to or from the SPI_DATA register is needed to complete a frame.
Figure 15-9. I2S Phillips standard timing diagram (DTLEN=10, CHLEN=1, CKPL=0)
Figure 15-10. I2S Phillips standard timing diagram (DTLEN=10, CHLEN=1, CKPL=1)
When the packet type is 32-bit data packed in 32-bit frame, two write or read operations to or
from the SPI_DATA register are needed to complete a frame. In transmission mode, if
0x8899AABB is going to be sent, the first data written to the SPI_DATA register should be
0x8899, and the second one should be 0xAABB. In reception mode, if 0x8899AABB is
received, the first data read from the SPI_DATA register should be 0x8899, and the second
one should be 0xAABB.
Figure 15-11. I2S Phillips standard timing diagram (DTLEN=01, CHLEN=1, CKPL=0)
Figure 15-12. I2S Phillips standard timing diagram (DTLEN=01, CHLEN=1, CKPL=1)
When the packet type is 24-bit data packed in 32-bit frame, two write or read operations to or
from the SPI_DATA register are needed to complete a frame. In transmission mode, if
0x8899AA is going to be sent, the first data written to the SPI_DATA register should be 0x8899,
and the second one should be 0xAAXX (the 8 LSB could be any value, but forced to 0x00
instead by hardware). In reception mode, if 0x8899AA is received, the first data read from the
SPI_DATA register should be 0x8899, and the second one should be 0xAA00.
Figure 15-13. I2S Phillips standard timing diagram (DTLEN=00, CHLEN=1, CKPL=0)
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Figure 15-14. I2S Phillips standard timing diagram (DTLEN=00, CHLEN=1, CKPL=1)
When the packet type is 16-bit data packed in 32-bit frame, only one write or read operation
to or from the SPI_DATA register is needed to complete a frame. The 16 remaining bits are
forced by hardware to 0x0000 to extend the data to 32-bit format.
MSB justified standard
For MSB justified standard, I2S_WS and I2S_SD are updated on the falling edge of I2S_CK.
The SPI_DATA register is handled in the exactly same way as that for I2S Phillips standard.
The timing diagrams for each configuration are shown below.
Figure 15-15. MSB justified standard timing diagram (DTLEN=00, CHLEN=0, CKPL=0)
Figure 15-16. MSB justified standard timing diagram (DTLEN=00, CHLEN=0, CKPL=1)
Figure 15-17. MSB justified standard timing diagram (DTLEN=10, CHLEN=1, CKPL=0)
Figure 15-18. MSB justified standard timing diagram (DTLEN=10, CHLEN=1, CKPL=1)
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Figure 15-19. MSB justified standard timing diagram (DTLEN=01, CHLEN=1, CKPL=0)
Figure 15-20. MSB justified standard timing diagram (DTLEN=01, CHLEN=1, CKPL=1)
Figure 15-21. MSB justified standard timing diagram (DTLEN=00, CHLEN=1, CKPL=0)
Figure 15-22. MSB justified standard timing diagram (DTLEN=00, CHLEN=1, CKPL=1)
LSB justified standard
For LSB justified standard, I2S_WS and I2S_SD are updated on the falling edge of I2S_CK.
In the case that the channel length is equal to the data length, LSB justified standard and
MSB justified standard are exactly the same. In the case that the channel length is greater
than the data length, the valid data is aligned to LSB for LSB justified standard while the valid
data is aligned to MSB for MSB justified standard. The timing diagrams for the cases that the
channel length is greater than the data length are shown below.
Figure 15-23. LSB justified standard timing diagram (DTLEN=01, CHLEN=1, CKPL=0)
Figure 15-24. LSB justified standard timing diagram (DTLEN=01, CHLEN=1, CKPL=1)
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When the packet type is 24-bit data packed in 32-bit frame, two write or read operations to or
from the SPI_DATA register are needed to complete a frame. In transmission mode, if
0x8899AA is going to be sent, the first data written to the SPI_DATA register should be
0xXX88 (the 8 MSB could be any value, but forced to 0x00 instead by hardware), and the
second one should be 0x99AA. In reception mode, if 0x8899AA is received, the first data read
from the SPI_DATA register should be 0x0088, and the second one should be 0x99AA.
Figure 15-25. LSB justified standard timing diagram (DTLEN=00, CHLEN=1, CKPL=0)
Figure 15-26. LSB justified standard timing diagram (DTLEN=00, CHLEN=1, CKPL=1)
When the packet type is 16-bit data packed in 32-bit frame, only one write or read operation
to or from the SPI_DATA register is needed to complete a frame. The 16 remaining bits are
forced by hardware to 0x0000 to extend the data to 32-bit format.
PCM standard
For PCM standard, I2S_WS and I2S_SD are updated on the rising edge of I2S_CK, and the
I2S_WS signal indicates frame synchronization information. Both the short frame
synchronization mode and the long frame synchronization mode are available and
configurable using the PCMSMOD bit in the SPI_I2SCTL register. The SPI_DATA register is
handled in the exactly same way as that for I2S Phillips standard. The timing diagrams for
each configuration of the short frame synchronization mode are shown below.
Figure 15-27. PCM standard short frame synchronization mode timing diagram
(DTLEN=00, CHLEN=0, CKPL=0)
Figure 15-28. PCM standard short frame synchronization mode timing diagram
(DTLEN=00, CHLEN=0, CKPL=1)
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Figure 15-29. PCM standard short frame synchronization mode timing diagram
(DTLEN=10, CHLEN=1, CKPL=0)
Figure 15-30. PCM standard short frame synchronization mode timing diagram
(DTLEN=10, CHLEN=1, CKPL=1)
Figure 15-31. PCM standard short frame synchronization mode timing diagram
(DTLEN=01, CHLEN=1, CKPL=0)
Figure 15-32. PCM standard short frame synchronization mode timing diagram
(DTLEN=01, CHLEN=1, CKPL=1)
Figure 15-33. PCM standard short frame synchronization mode timing diagram
(DTLEN=00, CHLEN=1, CKPL=0)
Figure 15-34. PCM standard short frame synchronization mode timing diagram
(DTLEN=00, CHLEN=1, CKPL=1)
The timing diagrams for each configuration of the long frame synchronization mode are shown
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below.
Figure 15-35. PCM standard long frame synchronization mode timing diagram
(DTLEN=00, CHLEN=0, CKPL=0)
Figure 15-36. PCM standard long frame synchronization mode timing diagram
(DTLEN=00, CHLEN=0, CKPL=1)
Figure 15-37. PCM standard long frame synchronization mode timing diagram
(DTLEN=10, CHLEN=1, CKPL=0)
Figure 15-38. PCM standard long frame synchronization mode timing diagram
(DTLEN=10, CHLEN=1, CKPL=1)
Figure 15-39. PCM standard long frame synchronization mode timing diagram
(DTLEN=01, CHLEN=1, CKPL=0)
Figure 15-40. PCM standard long frame synchronization mode timing diagram
(DTLEN=01, CHLEN=1, CKPL=1)
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Figure 15-41. PCM standard long frame synchronization mode timing diagram
(DTLEN=00, CHLEN=1, CKPL=0)
Figure 15-42. PCM standard long frame synchronization mode timing diagram
(DTLEN=00, CHLEN=1, CKPL=1)
15.4.3. Clock generator
Figure 15-43. Block diagram of I2S clock generator
8-bit
Configurable
Divider
I2SCLK
frequency dividing ratio =
DIV * 2 + OF
DIV4
DIV2
1
0
CHLEN
0
1
MCKOE
I2S_CK
I2S_MCK
The block diagram of I2S clock generator is shown above. The I2S interface clocks are
configured by the DIV bits, the OF bit, the MCKOEN bit in the SPI_I2SPSC register and the
CHLEN bit in the SPI_I2SCTL register. The source clock is SYSCLK. The I2S bitrate can be
calculated by the formulas shown in the following table.
Table 15-2. I2S bitrate calculation formulas
MCKOEN
CHLEN
Formula
0
0
I2SCLK / (DIV * 2 + OF)
0
1
I2SCLK / (DIV * 2 + OF)
1
0
I2SCLK / (8 * (DIV * 2 + OF))
1
1
I2SCLK / (4 * (DIV * 2 + OF))
The relationship between audio sampling frequency (Fs) and I2S bitrate is defined by the
following formula.
Fs = I2S bitrate / (number of bits per channel * number of channels)
So, in order to get the desired audio sampling frequency, the clock generator needs to be
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461
configured according to the formulas listed in the following table.
Table 15-3. Audio sampling frequency calculation formulas
MCKOEN
CHLEN
Formula
0
0
I2SCLK / (32 * (DIV * 2 + OF))
0
1
I2SCLK / (64 * (DIV * 2 + OF))
1
0
I2SCLK / (256 * (DIV * 2 + OF))
1
1
I2SCLK / (256 * (DIV * 2 + OF))
The configuration and precision of audio sampling frequencies in common use are listed in
the following table. The precision is calculated in the case when using standard 8 MHz HXTAL.
Table 15-4. Audio sampling frequency configuration and precision
Targe
t
Fs(Hz
)
SYSCL
K
(MHz)
MCKOE
N
CHLEN = 0
CHLEN = 1
DI
V
O
F
Real
Fs(Hz)
Error
DI
V
O
F
Real
Fs(Hz)
Error
96000
72
No
11
1
97826.0
9
1.90
%
6
0
93750
2.34
%
96000
72
Yes
1
1
93750
2.34
%
1
1
93750
2.34
%
96000
48
No
8
0
93750
2.34
%
4
0
93750
2.34
%
96000
48
Yes
1
0
93750
2.34
%
1
0
93750
2.34
%
48000
72
No
23
1
47872.3
4
0.27
%
11
1
48913.0
4
1.90
%
48000
72
Yes
3
0
46875
2.34
%
3
0
46875
2.34
%
48000
48
No
15
1
48387.1
0.81
%
8
0
46875
2.34
%
48000
48
Yes
2
0
46875
2.34
%
2
0
46875
2.34
%
44100
72
No
25
1
44117.6
5
0.04
%
13
0
43269.2
3
1.88
%
44100
72
Yes
3
0
46875
6.29
%
3
0
46875
6.29
%
44100
48
No
17
0
44117.6
5
0.04
%
8
1
44117.6
5
0.04
%
44100
48
Yes
2
0
46875
6.29
%
2
0
46875
6.29
%
32000
72
No
35
0
32142.8
6
0.44
%
17
1
32142.8
6
0.44
%
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Targe
t
Fs(Hz
)
SYSCL
K
(MHz)
MCKOE
N
CHLEN = 0
CHLEN = 1
DI
V
O
F
Real
Fs(Hz)
Error
DI
V
O
F
Real
Fs(Hz)
Error
32000
72
Yes
4
1
31250
2.34
%
4
1
31250
2.34
%
32000
48
No
23
1
31914.8
9
0.27
%
11
1
32608.7
1.90
%
32000
48
Yes
3
0
31250
2.34
%
3
0
31250
2.34
%
22050
72
No
51
0
22058.8
2
0.04
%
25
1
22058.8
2
0.04
%
22050
72
Yes
6
1
21634.6
1
1.88
%
6
1
21634.6
1
1.88
%
22050
48
No
34
0
22058.8
2
0.04
%
17
0
22058.8
2
0.04
%
22050
48
Yes
4
1
20833.3
3
5.52
%
4
1
20833.3
3
5.52
%
16000
72
No
70
1
15675.7
5
0.27
%
35
0
16071.4
3
0.45
%
16000
72
Yes
9
0
15625
2.34
%
9
0
15625
2.34
%
16000
48
No
47
0
15957.4
5
0.27
%
23
1
15957.4
5
0.27
%
16000
48
Yes
6
0
15625
2.34
%
6
0
15625
2.34
%
11025
72
No
10
2
0
11029.4
1
0.04
%
51
0
11029.4
1
0.04
%
11025
72
Yes
13
0
10817.3
1.88
%
13
0
10817.3
1.88
%
11025
48
No
68
0
11029.4
1
0.04
%
34
0
11029.4
1
0.04
%
11025
48
Yes
8
1
11029.4
1
0.04
%
8
1
11029.4
1
0.04
%
8000
72
No
14
0
1
8007.11
0.09
%
70
1
7978.72
0.27
%
8000
72
Yes
17
1
8035.71
0.45
%
17
1
8035.71
0.45
%
8000
48
No
94
0
7978.72
0.27
%
47
0
7978.72
0.27
%
8000
48
Yes
11
1
8152.17
1.90
%
11
1
8152.17
1.90
%
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15.4.4. Operation
Operation modes
The operation mode is selected by the I2SOPMOD bits in the SPI_I2SCTL register. There are
four available operation modes, including master transmission mode, master reception mode,
slave transmission mode, and slave reception mode. The direction of I2S interface signals for
each operation mode is shown in the following table.
Table 15-5. Direction of I2S interface signals for each operation mode
Operation mode
I2S_MCK
I2S_CK
I2S_WS
I2S_SD
Master transmission
output or NU(1)
output
output
output
Master reception
output or NU(1)
output
output
input
Slave transmission
input or NU(1)
input
input
output
Slave reception
input or NU(1)
input
input
input
1. NU means the pin is not used by I2S and can be used by other functions.
Status flags and interrupts
There are six status flags implemented in the SPI_STAT register, including TBE, RBNE,
TRANS, I2SCH, TXURERR, and RXORERR. The user can use them to fully monitor the state
of the I2S bus.
Transmit buffer empty flag (TBE)
This bit is set when the transmit buffer is empty. An interrupt may be generated if the
TBEIE bit in the SPI_CTL1 register is set. The software can write the next data to the
transmit buffer by writing it to the SPI_DATA register. The TBE bit is cleared by a write
operation to the SPI_DATA register.
Receive buffer not empty flag (RBNE)
This bit is set when receive buffer is not empty. An interrupt may be generated if the
RBNEIE bit in the SPI_CTL1 register is set. It indicates valid data has been received and
stored in the receive buffer. The software can read the data by reading the SPI_DATA
register. The RBNE bit is cleared by a read operation to the SPI_DATA register.
Transmitting On-Going flag (TRANS)
This TRANS flag is set and cleared by hardware. It indicates the state of the
communication layer of the I2S. The TRANS flag is useful to detect the end of a transfer
if the software wants to disable the I2S. This avoids corrupting the last transfer. For this,
the procedure described below must be strictly respected. The TRANS flag is set when
a transfer starts, except in master reception mode where the flag is kept low during
reception. It is cleared when the I2S is disenabled or a transfer complete. When
communication is not continuous, the TRANS flag is low between each communication.
When communication is continuous, the TRANS flag is kept high during all the transfers
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in master transmission mode, and goes low for one I2S clock cycle between each
transfer in slave mode.
I2S channel side flag (I2SCH)
In transmission mode, this flag is refreshed at the moment when the TBE flag goes high,
indicating the channel side to which the data to transfer belongs. In reception mode, this
flag is refreshed at the moment when the RBNE flag goes high, indicating the channel
side to which the received data belongs. Notice that in case of error (TXURERR or
RXORERR) this flag becomes not reliable and I2S needs to be switched off and switched
on before resuming the communication. Besides, this flag has no meaning in the PCM
standard.
Transmission underrun error flag (TXURERR)
This flag is set when the first clock for data transmission appears while the transmit buffer
is still empty in slave transmission mode. An interrupt may be generated if the ERRIE bit
in the SPI_CTL1 register is set. This flag is cleared by a read operation to the SPI_STAT
register.
Reception overrun error flag (RXORERR)
This flag is set when data are received and the previous data has not been read from
the SPI_DATA register yet in reception mode. An interrupt may be generated if the ERRIE
bit in the SPI_CTL1 register is set. In the case, the contents in receive buffer are not
updated with the newly received data. A read operation to the SPI_DATA register returns
the previous correctly received data. All other subsequently received half-words are lost.
This flag is cleared by a read access to the SPI_DATA register followed by a read access
to the SPI_STAT register.
I2S interrupt events and corresponding enable bits are summed up in the following table.
Table 15-6. I2S interrupt
Interrupt event
Flag
Enable bit
Transmit buffer empty
TBE
TBEIE
Receive buffer not empty
RBNE
RBNEIE
Transmission underrun error
TXURERR
ERRIE
Reception overrun error
RXORERR
ERRIE
Initialization sequence
I2S initialization sequence contains the five steps shown below. In order to initialize I2S
working in master mode, all the five steps should be done. In order to initialize I2S working in
slave mode, only step 2, step 3, step 4 and step 5 should be done.
Step 1: Configure the DIV[7:0] bits, the OF bit, and the MCKOEN bit in the SPI_I2SPSC
register, in order to define the I2S bitrate and whether I2S_MCK needs to be provided or
not.
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Step 2: Configure the CKPL in the SPI_I2SCTL register, in order to define the idle state
clock polarity.
Step 3: Configure the I2SSEL bit, the I2SSTD[1:0] bits, the PCMSMOD bit, the
I2SOPMOD[1:0] bits, the DTLEN[1:0] bits, and the CHLEN bit in the SPI_I2SCTL register,
in order to define the I2S feature.
Step 4: Configure the TBEIE bit, the RBNEIE bit, the ERRIE bit, the DMATEN bit, and
the DMAREN bit in the SPI_CTL1 register, in order to select the potential interrupt
sources and the DMA capabilities. This step is optional.
Step 5: Set the I2SEN bit in the SPI_I2SCTL register to enable I2S.
Master transmission sequence
The TBE flag is used to control the transmission sequence. As is mentioned before, the TBE
flag indicates the transmit buffer is empty, and may generate an interrupt if the TBEIE bit in
the SPI_CTL1 register is set. At the beginning, the transmit buffer is empty (TBE is high) and
no transmission sequence is processing in the shift register. When a half word is written to
the SPI_DATA register (TBE goes low), the data is transferred from the transmit buffer to the
shift register (TBE goes high) immediately. At the moment, the transmission sequence begins.
The data is parallel loaded into the 16-bit shift register, and shifted out serially to the I2S_SD
pin, MSB first. The next data should be written to the SPI_DATA register, when the TBE flag
is high. After a write operation to the SPI_DATA register, the TBE flag goes low. When the
current transmission finishes, the data in the transmit buffer is loaded into the shift register,
and the TBE flag goes back high. To ensure a continuous audio data transmission, it is
mandatory to write the SPI_DATA register with the next data to transmit before the end of the
current transmission.
For all standards except PCM, the I2SCH flag is used to distinguish the channel side to which
the data to transfer belongs. The I2SCH flag is refreshed at the moment when the TBE flag
goes high. At the beginning, the I2SCH flag is low, indicating the left channel data should be
written to the SPI_DATA register.
In order to switch off I2S, it is mandatory to clear the I2SEN bit after the TBE flag is high and
the TRANS flag is low.
Master reception sequence
The RBNE flag is used to control the reception sequence. As is mentioned before, the RBNE
flag indicates the receive buffer is not empty, and may generate an interrupt if the RBNEIE bit
in the SPI_CTL1 register is set. The reception sequence begins immediately when the I2SEN
bit in the SPI_I2SCTL register is set. At the beginning, the receive buffer is empty (RBNE is
low). When a reception sequence finishes, the received data in the shift register is loaded into
the receive buffer (RBNE goes high). The data should be read from the SPI_DATA register,
when the RBNE flag is high. After a read operation to the SPI_DATA register, the RBNE flag
goes low. It is mandatory to read the SPI_DATA register before the end of the next reception.
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Or, reception overrun error occurs. The RXORERR flag is set and an interrupt may be
generated if the ERRIE bit in the SPI_CTL1 register is set. In this case, it is mandatory to
switch off and switch on I2S before resuming the communication.
For all standards except PCM, the I2SCH flag is used to distinguish the channel side to which
the received data belongs. The I2SCH flag is refreshed at the moment when the RBNE flag
goes high.
In order to switch off I2S, specific actions are required to ensure that I2S completes the
transfer cycle properly without initiating a new data transfer. The actions depend on the audio
standard selected, and on the configuration of the data length and the channel length. The
actions for each case are described below.
16-bit data packed in 32-bit frame in the LSB justified standard (DTLEN = 00, CHLEN =
1, and I2SSTD = 10)
1. Wait for the second to last RBNE
2. Then wait 17 I2S clock cycles
3. Clear the I2SEN bit
16-bit data packed in 32-bit frame in the audio standards except the LSB justified
standard (DTLEN = 00, CHLEN = 1, and I2SSTD is not equal to 10)
1. Wait for the last RBNE
2. Then wait one I2S clock cycle
3. Clear the I2SEN bit
For all other cases
1. Wait for the second to last RBNE
2. Then wait one I2S clock cycle
3. Clear the I2SEN bit
Slave transmission sequence
The transmission sequence in slave mode is similar to that in master mode. The difference
between them is described below.
In slave mode, the slave has to be enabled before the external master starts the
communication. The transmission sequence begins when the external master sends the clock
and when the I2S_WS signal requests the transfer of data. The data has to be written to the
SPI_DATA register before the master initiates the communication. To ensure a continuous
audio data transmission, it is mandatory to write the SPI_DATA register with the next data to
transmit before the end of the current transmission. Or, transmission underrun error occurs.
The TXURERR flag is set and an interrupt may be generated if the ERRIE bit in the SPI_CTL1
register is set. In this case, it is mandatory to switch off and switch on I2S before resuming
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the communication. In slave mode, I2SCH is sensitive to the I2S_WS signal coming from the
external master.
In order to switch off I2S, it is mandatory to clear the I2SEN bit after the TBE flag is high and
the TRANS flag is low.
Slave reception sequence
The reception sequence in slave mode is similar to that in master mode. The difference
between them is described below.
In slave mode, the slave has to be enabled before the external master starts the
communication. The reception sequence begins when the external master sends the clock
and when the I2S_WS signal requests the transfer of data. In slave mode, I2SCH is sensitive
to the I2S_WS signal coming from the external master.
In order to switch off I2S, it is mandatory to clear the I2SEN bit immediately after receiving
the last RBNE.
15.4.5. DMA features
DMA is working in exactly the same way as for the SPI mode. The only difference is that the
CRC feature is not available in I2S mode.
15.5. SPI registers
15.5.1. Control register 0 (SPI_CTL0)
Address offset: 0x00
Reset value: 0x0000
This register can be accessed by half-word (16-bit) or word (32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
BDE
N
BDOE
N
CRCEN
CRCNT
FF16
RO
SWNSSEN
SWNSS
LF
SPIEN
PSC [2:0]
MSTMOD
CKPL
CKPH
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
15
BDEN
Bidirectional Enable
0: 2 line unidirectional transmit mode
1: 1 line bidirectional transmit mode. The information transfer between the MOSI pin in
master and the MISO pin in slave.
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14
BDOEN
Bidirectional Transmit Output Enable
When BDEN is set, this bit determines the direction of transfer.
0: Work in receive-only mode
1: Work in transmit-only mode
13
CRCEN
CRC Calculation Enable
0: CRC calculation is disabled
1: CRC calculation is enabled.
12
CRCNT
CRC Transfer Next
0: Next transfer is Data
1: Next transfer is CRC value (TCR)
When the transfers are managed by DMA, CRC value is transferred by hardware. This bit
should be cleared.
In full-duplex or transmit-only mode, set this bit after the last data is written to SPI_DATA
register. In receive only mode, set this bit after the second last data is received.
11
FF16
Data frame format
0: 8-bit data frame format
1: 16-bit data frame format
10
RO
Receive only
When BDEN is cleared, this bit determines the direction of transfer.
0: Full-duplex
1: Receive-only
9
SWNSSEN
NSS Software Mode Selection
0: NSS hardware mode. The NSS pin input depends on IO.
1: NSS software mode. The NSS pin input depends on SWNSS bit.
8
SWNSS
NSS Pin Selection In NSS Software Mode
0: NSS pin is pull low
1: NSS pin is pull high
This bit has an effect only when the SWNSSEN bit is set.
7
LF
LSB First Mode
0: Transmit MSB first
1: Transmit LSB first
6
SPIEN
SPI Enable
0: SPI peripheral is disabled
1: SPI peripheral is enabled
5:3
PSC[2:0]
Master Clock Prescaler Selection
000: PCLK/2 100: PCLK/32
001: PCLK/4 101: PCLK/64
010: PCLK/8 110: PCLK/128
011: PCLK/16 111: PCLK/256
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PCLK means PCLK2 when using SPI0 or PCLK1 when using SPI1
2
MSTMOD
Master Selection
0: Slave mode
1: Master mode
1
CKPL
Clock Polarity Selection
0: CLK pin is pulled low when SPI is idle
1: CLK pin is pulled high when SPI is idle
0
CKPH
Clock Phase Selection
0: Capture the first data at the first clock transition.
1: Capture the first data at the second clock transition
15.5.2. Control register 1 (SPI_CTL1)
Address offset: 0x04
Reset value: 0x0000
This register can be accessed by half-word (16-bit) or word (32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
TBEIE
RBNEIE
ERRIE
Reserved.
NSSDRV
DMATEN
DMAREN
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
15:8
Reserved
Must be kept at reset value.
7
TBEIE
Transmit Buffer Empty Interrupt Enable
0: TBE interrupt is disenabled.
1: TBE interrupt is enabled. An interrupt is generated when the TBE bit is set
6
RBNEIE
Receive Buffer Not Empty Interrupt Enable
0: RBNE interrupt is disenabled.
1: RBNE interrupt is enabled. An interrupt is generated when the RBNE bit is set
5
ERRIE
Errors Interrupt Enable.
0: Error interrupt is disabled.
1: Error interrupt is enabled. An interrupt is generated when the CRCERR bit or the CONFERR
bit or the RXORERR bit or the TXURERR bit is set.
4:3
Reserved
Must be kept at reset value.
2
NSSDRV
Drive NSS Output
0: NSS output is disabled.
1: NSS output is enabled. If the NSS pin is configured as output, the NSS pin is pulled low in
master mode when SPI is enabled.
If the NSS pin is configured as input, the NSS pin should be pulled high in master mode, and
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this bit has on effect.
1
DMATEN
Transmit Buffer DMA Enable
0: Transmit buffer DMA is disabled
1: Transmit buffer DMA is enabled, when the TBE bit in SPI_STAT is set, it will be a DMA
request at corresponding DMA channel.
0
DMAREN
Receive Buffer DMA Enable
0: Receive buffer DMA is disabled
1: Receive buffer DMA is enabled, when the RBNE bit in SPI_STAT is set, it will be a DMA
request at corresponding DMA channel.
15.5.3. Status register (SPI_STAT)
Address offset: 0x08
Reset value: 0x0002
This register can be accessed by half-word (16-bit) or word (32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
TRANS
RXORERR
CONFERR
CRCERR
TXURERR
I2SCH
TBE
RBNE
r
r
r
rc_w0
r
r
r
r
Bits
Fields
Descriptions
15:8
Reserved
Must be kept at reset value.
7
TRANS
Transmitting On-going Bit
0: SPI or I2S is idle.
1: SPI or I2S is currently transmitting and/or receiving a frame, or the transmit buffer is not
empty.
This bit is set and cleared by hardware.
6
RXORER
R
Reception Overrun Error Bit
0: No reception overrun error occurred.
1: Reception overrun error occurred.
This bit is set by hardware and cleared by a read operation on the SPI_DATA register
followed by a read access to the SPI_STAT register.
5
CONFERR
SPI Configuration error
0: No configuration fault occurred
1: Configuration fault occurred. (In master mode, the NSS pin is pulled low in NSS
hardware mode or SWNSS bit is low in NSS software mode.)
This bit is set by hardware and cleared by a read or write operation on the SPI_STAT
register followed by a write access to the SPI_CTL0 register.
This bit is not used in I2S mode.
4
CRCERR
SPI CRC Error Bit
0: The SPI_RCR value is equals to the received CRC data at last.
1: The SPI_RCR value is not equals to the received CRC data at last.
This bit is set by hardware and cleared by software writing 0.
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This bit is not used in I2S mode.
3
TXURERR
Transmission underrun error bit
0: No transmission underrun error occurred.
1: Transmission underrun error occurred.
This bit is set by hardware and cleared by a read operation on the SPI_STAT register.
This bit is not used in SPI mode.
2
I2SCH
I2S channel side
0: Channel Left has to be transmitted or has been received.
1: Channel Right has to be transmitted or has been received.
This bit is set and cleared by hardware.
This bit is not used in SPI mode, and has no meaning in the I2S PCM mode.
1
TBE
Transmit Buffer Empty
0: Transmit buffer is not empty
1: Transmit buffer is empty
0
RBNE
Receive Buffer Not Empty
0: Receive buffer is empty
1: Receive buffer is not empty
15.5.4. Data register (SPI_DATA)
Address offset: 0x0C
Reset value: 0x0000
This register can be accessed by half-word (16-bit) or word (32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
SPI_DATA[15:0]
rw
Bits
Fields
Descriptions
15:0
SPI_DATA[15:0]
Data transfer register. The hardware has two buffers, including transmit buffer and
receive buffer. Write data to SPI_DATA will save the data to transmit buffer and read
data from SPI_DATA will get the data from receive buffer.
When the data frame format is set to 8-bit data, the SPI_DATA[15:8] is forced to 0 and
the SPI_DATA[7:0] is used for transmission and reception, transmit buffer and receive
buffer are 8-bits. If the Data frame format is set to 16-bit data, the SPI_DATA[15:0] is
used for transmission and reception, transmit buffer and receive buffer are 16-bit.
15.5.5. CRC polynomial register (SPI_CRCPOLY)
Address offset: 0x10
Reset value: 0x0007
This register can be accessed by half-word (16-bit) or word (32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
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CPR [15:0]
rw
Bits
Fields
Descriptions
15:0
CPR[15:0]
This register contains the CRC polynomial and used for CRC calculation. The default
value is 0007h.
15.5.6. Receive CRC register (SPI_RCRC)
Address offset: 0x14
Reset value: 0x0000
This register can be accessed by half-word (16-bit) or word (32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RCR[15:0]
r
Bits
Fields
Descriptions
15:0
RCR[15:0]
When the CRCEN bit of SPI_CTL0 is set, the hardware computes the CRC value of the
received bytes and save them in RCR register. If the Data frame format is set to 8-bit data,
CRC calculation is done based on CRC8 standard, and save the value in RCR[7:0], when the
Data frame format is set to 16-bit data, CRC calculation is done based on CRC16 standard,
and save the value in RCR[15:0].
The hardware computes the CRC value after each received bit, when the TRANS is set, a read
to this register could return an intermediate value.
This register is reset when the CRCEN bit or the SPIEN bit of SPI_CTL0 is cleared.
15.5.7. Transmit CRC register (SPI_TCRC)
Address offset: 0x18
Reset value: 0x0000
This register can be accessed by half-word (16-bit) or word (32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
TCR[15:0]
r
Bits
Fields
Descriptions
15:0
TCR[15:0]
When the CRCEN bit of SPI_CTL0 is set, the hardware computes the CRC value of the
transmitted bytes and save them in TCR register. If the Data frame format is set to 8-bit data,
CRC calculation is done based on CRC8 standard, and save the value in TCR[7:0], when the
Data frame format is set to 16-bit data, CRC calculation is done based on CRC16 standard,
and save the value in TCR[15:0].
The hardware computes the CRC value after each transmitted bit, when the TRANS is set, a
read to this register could return an intermediate value. The different frame format (LF bit of
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473
the SPI_CTL0) will get different CRC value.
This register is reset when the CRCEN bit or the SPIEN bit of SPI_CTL0 is cleared.
15.5.8. I2S control register (SPI_I2SCTL)
Address offset: 0x1C
Reset value: 0x0000
This register can be accessed by half-word (16-bit) or word (32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
I2SS
EL
I2SE
N
I2SOPMOD[1:
0]
PCM
SMO
D
Rese
rved
I2SSTD[1:0]
CKPL
DTLEN[1:0]
CHL
EN
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
15:12
Reserved
Must be kept at reset value
11
I2SSEL
I2S mode selection
0: SPI mode
1: I2S mode
This bit should be configured when SPI or I2S is disenabled.
10
I2SEN
I2S enable
0: I2S is disenable
1: I2S is enable
This bit is not used in SPI mode.
9:8
I2SOPMOD[1:0]
I2S operation mode
00: Slave transmission mode
01: Slave reception mode
10: Master transmission mode
11: Master reception mode
This bit should be configured when I2S is disenabled.
This bit is not used in SPI mode.
7
PCMSMOD
PCM frame synchronization mode
0: Short frame synchronization
1: long frame synchronization
This bit has a meaning only when PCM standard is used.
This bit should be configured when I2S is disenabled.
This bit is not used in SPI mode.
6
Reserved
Must be kept at reset value
5:4
I2SSTD[1:0]
I2S standard selection
00: I2S Phillips standard
01: MSB justified standard
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10: LSB justified standard
11: PCM standard
These bits should be configured when I2S is disenabled.
These bits are not used in SPI mode.
3
CKPL
Idle state clock polarity
0: The idle state of I2S_CK is low level
1: The idle state of I2S_CK is high level
This bit should be configured when I2S is disenabled.
This bit is not used in SPI mode.
2:1
DTLEN[1:0]
Data length
00: 16 bits
01: 24 bits
10: 32 bits
11: Reserved
These bits should be configured when I2S is disenabled.
These bits are not used in SPI mode.
0
CHLEN
Channel length
0: 16 bits
1: 32 bits
The channel length must be equal to or greater than the data length.
This bit should be configured when I2S is disenabled.
This bit is not used in SPI mode.
15.5.9. I2S prescaler register (SPI_I2SPSC)
Address offset: 0x20
Reset value: 0x0002
This register can be accessed by half-word (16-bit) or word (32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
MCK
OEN
OF
DIV[7:0]
rw
rw
rw
Bits
Fields
Descriptions
15:10
Reserved
Must be kept at reset value
9
MCKOEN
I2S_MCK output enable
0: I2S_MCK output is disenable
1: I2S_MCK output is enable
This bit should be configured when I2S is disenabled.
This bit is not used in SPI mode.
8
OF
Odd factor for the prescaler
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0: Real divider value is DIV * 2
1: Real divider value is DIV * 2 + 1
This bit should be configured when I2S is disenabled.
This bit is not used in SPI mode.
7:0
DIV[7:0]
Dividing factor for the prescaler
Real divider value is DIV * 2 + OF.
DIV must not be 0.
These bits should be configured when I2S is disenabled.
These bits are not used in SPI mode.
15.5.10. Quad wire control register (SPI_QCTL) of GD32F170xx and GD32F190xx
devices
Address offset: 0x80
Reset value: 0x0000
This register can be accessed by half-word (16-bit) or word (32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
IO23
_DR
V
QRD
QMO
D
rw
rw
rw
Bits
Fields
Descriptions
15:3
Reserved
Must be kept at reset value
2
IO23_DRV
Drive IO2 and IO3 enable
0: IO2 and IO3 are not driven in single wire mode
1: IO2 and IO3 are driven to high in single wire mode
This bit is only available in SPI1.
1
QRD
Quad wire read select.
0: SPI is in quad wire write mode
1: SPI is in quad wire read mode
This bit should be only be configured when SPI is not busy (TRANS bit cleared)
This bit is only available in SPI1.
0
QMOD
Quad wire mode enable.
0: SPI is in single wire mode
1: SPI is in quad wire mode
This bit should only be configured when SPI is not busy (TRANS bit cleared).
This bit is only available in SPI1.
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16. Comparator (CMP)
16.1. Introduction
The general purpose comparators, CMP0 and CMP1, can work either standalone (all terminal
are available on I/Os) or together with the timers. They can be used for a variety of functions
including wakeup from low-power mode when triggered by an analog signal, analog signal
conditioning and cycle-by-cycle current control loop when combined with the DAC and a PWM
output from a timer.
16.2. Main features
Rail-to-rail comparators
Configurable hysteresis
Configurable speed and consumption
Each comparator has configurable analog input source
DAC
3 I/O pins
The whole or sub-multiple values of internal reference voltage
Window comparator
Outputs to I/O
Outputs to timers for triggering
Outputs to EXTI
16.3. Function description
The block diagrams of CMP are shown below.
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Figure 16-1. CMP block diagram of GD32F130xx and GD32F150xx devices
Note: VREFINT is 1.2V.
Figure 16-2. CMP block diagram of GD32F170xx and GD32F190xx devices
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Note: VREFINT is 1.2V.
16.3.1. CMP clock and reset
The CMP clock provided by the clock controller is synchronous with the PCLK. The CMP
share common reset and clock enable bits with SYSCFG.
16.3.2. CMP inputs and outputs
The I/Os must be configured in analog mode in the GPIOs registers before they are selected
as CMPs inputs.
Considering pin definitions in Datasheet, the CMP output must be connected to corresponding
alternate I/Os.
A variety of timer inputs can be internally connected to the CMP output to realize the following
functions:
Input capture for timing measures
Emergency shut-down of PWM signals, using BKIN
Cycle-by-cycle current control, using OCPRE_CLR inputs
In order to work even in Deep-sleep mode, the polarity selection logic and the output
redirection to the port work independently from PCLK.
It is possible to have the CMP output simultaneously redirected internally and externally.
The CMP outputs are internally connected to the extended interrupts and events controller.
Each CMP has its own EXTI line and can generate either interrupts or events. The same
mechanism is used to exit from power saving modes.
16.3.3. CMP power mode
For a given application, the CMP power consumption versus propagation delay can be
adjusted to have the optimum trade-off by configuring bits CMPxM [1:0] in CMP_CS register.
The CMP works fastest with highest power consumption when CMPxM = 2’b00, while works
slowest with lowest power consumption when CMPxM = 2’b11.
16.3.4. CMP hysteresis
In order to avoid spurious output transitions that caused by the noise signal, the CMP includes
a programmable hysteresis to force the hysteresis value using external components. This
function can be shut down when you don't need it (for example, exiting from the power saving
mode).
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16.3.5. CMP register write protection
Out of security concerns for applications, such as over-current or thermal protection, and
having specific functional safety requirements, it is a need to insure that the CMP’s
configuration cannot be changed in case of spurious register access or program counter
corruption.
For this consideration, the CMP control and status register (CMP_CS) can be entered into
the write protect state by setting CMPxLK bit to 1, which should be done once the
programming is completed. The whole CMP_CS register will become read-only, including the
CMPxLK bit. Only the MCU reset can reset the CMPxLK bit.
16.4. CMP registers
16.4.1. Control/status register (CMP_CS)
For GD32F130xx and GD32F150xx devices
Address offset: 0x00
Reset value: 0x0000 0000
This register has to be accessed by word (32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
CMP1LK
CMP1O
CMP1HST[1:0]
CMP1PL
CMP1OSEL[2:0]
WNDEN
CMP1MSEL[2:0]
CMP1M
Reserved
CMP1EN
rwo
r
rw/r
rw/r
rw/r
rw/r
rw/r
rw/r
rw/r
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
CMP0LK
CMP0O
CMP0HST[1:0]
CMP0PL
CMP0OSEL[2:0]
Reserved
CMP0MSEL[2:0]
CMP0M[1:0]
CMP0S
CMP0EN
rwo
r
rw/r
rw/r
rw/r
rw/r
rw/r
rw/r
rw/r
Bits
Fields
Descriptions
31
CMP1LK
CMP1 lock
This bit allows to have all control bits of CMP1 as read-only. This bit is write-once.
It can only be cleared by a system reset once It is set by software.
0: CMP_CS[31:16] bits are read-write
1: CMP_CS[31:16] bits are read-only
30
CMP1O
CMP1 output
This is a copy of CMP1 output state, which is read only.
0: Non-inverting input below inverting input and the output is low
1: Non-inverting input above inverting input and the output is high
29:28
CMP1HST[1:0]
CMP1 hysteresis
These bits are used to control the hysteresis level.
00: No hysteresis
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01: Low hysteresis
10: Medium hysteresis
11: High hysteresis
27
CMP1PL
Polarity of CMP1 output
This bit is used to select the CMP1 output.
0: Output is not inverted
1: Output is inverted
26:24
CMP1OSEL[2:0]
CMP1 output selection
These bits are used to select the destination of the CMP1 output.
000: No selection
001: TIMER 0 break input
010: TIMER 0 channel0 Input capture
011: TIMER 0 OCPRE_CLR input
100: TIMER1 channel3 input capture
101: TIMER1 OCPRE_CLR input
110: TIMER2 channel0 input capture
111: TIMER2 OCPRE_CLR input
23
WNDEN
Window mode enable
This bit is used to disconnect the CMP1_IP input of CMP1 from PA3 and connect it
to CMP0’s CMP0_IP input.
0: CMP1_IP is connected to PA3
1: CMP1_IP is connected to CMP0_IP
22:20
CMP1MSEL[2:0]
CMP1_M input selection
These bits are used to select the source connected to the CMP1_M input of the
CMP1.
000: VREFINT/4
001: VREFINT /2
010: VREFINT *3/4
011: VREFINT
100: PA4 (DAC0)
101: PA5
110: PA2
111: Reserved
19:18
CMP1M[1:0]
CMP1 mode
These bits are used to control the operating mode of the CMP1 adjust the
speed/consumption.
00: High speed / full power
01: Medium speed / medium power
10: Low speed / low power
11: Very-low speed / ultra-low power
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17
Reserved
Must be kept at reset value
16
CMP1EN
CMP1 enable
0: CMP1 disabled
1: CMP1 enabled
15
CMP0LK
CMP0 lock
This bit allows to have all control bits of CMP0 as read-only. This bit is write-once.
It can only be cleared by a system reset once It is set by software.
0: CMP_CS[15:0] bits are read-write
1: CMP_CS[15:0] bits are read-only
14
CMP0O
CMP0 output
This is a copy of CMP0 output state, which is read only.
0: Non-inverting input below inverting input and the output is low
1: Non-inverting input above inverting input and the output is high
13:12
CMP0HST[1:0]
CMP0 hysteresis
These bits are used to control the hysteresis level.
00: No hysteresis
01: Low hysteresis
10: Medium hysteresis
11: High hysteresis
11
CMP0PL
Polarity of CMP0 output
This bit is used to select the CMP0 output.
0 : Output is not inverted
1 : Output is inverted
10:8
CMP0OSEL[2:0]
Comparator 0 output selection
These bits are used to select the destination of the CMP0 output.
000: no selection
001: TIMER 0 break input
010: TIMER 0 channel0 Input capture
011: TIMER 0 OCPRE_CLR input
100: TIMER1 channel3 input capture
101: TIMER1 OCPRE_CLR input
110: TIMER2 channel0 input capture
111: TIMER2 OCPRE_CLR input
7
Reserved
Must be kept at reset value
6:4
CMP0MSEL[2:0]
CMP0_M input selection
These bits are used to select the source connected to the CMP0_M input of the
CMP0.
000: VREFINT /4
001: VREFINT /2
010: VREFINT *3/4
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011: VREFINT
100: PA4 (DAC0)
101: PA5
110: PA0
111: Reserved
3:2
CMP0M[1:0]
CMP0 mode
These bits are used to control the operating mode of the CMP0 adjust the
speed/consumption.
00: High speed/ full power
01: Medium speed/ medium power
10: Low speed/ low power
11: Very-low speed/ ultra-low power
1
CMP0S
CMP0 switch
This bit is used to closes a switch between CMP0 non-inverting input on PA0 and
PA4 (DAC0) I/O.
0: Switch open
1: Switch closed
0
CMP0EN
CMP0 enable
0: CMP0 disabled
1: CMP0 enabled
For GD32F170xx and GD32F190xx devices
Address offset: 0x00
Reset value: 0x0000 0000
This register has to be accessed by word (32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
CMP1LK
CMP1O
CMP1HST[1:0]
CMP1PL
CMP1OSEL[2:0]
WNDEN
CMP1MSEL[2:0]
CMP1M
Reserved
CMP1EN
rwo
r
rw/r
rw/r
rw/r
rw/r
rw/r
rw/r
rw/r
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
CMP0LK
CMP0O
CMP0HST[1:0]
CMP0PL
CMP0OSEL[2:0]
Reserved
CMP0MSEL[2:0]
CMP0M[1:0]
CMP0S
CMP0EN
rwo
r
rw/r
rw/r
rw/r
rw/r
rw/r
rw/r
rw/r
Bits
Fields
Descriptions
31
CMP1LK
CMP1 lock
This bit allows to have all control bits of CMP1 as read-only. This bit is write-once.
It can only be cleared by a system reset once It is set by software.
0: CMP_CS[31:16] bits are read-write
1: CMP_CS[31:16] bits are read-only
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30
CMP1O
CMP1 output
This is a copy of CMP1 output state, which is read only.
0: Non-inverting input below inverting input and the output is low
1: Non-inverting input above inverting input and the output is high
29:28
CMP1HST[1:0]
CMP1 hysteresis
These bits are used to control the hysteresis level.
00: No hysteresis
01: Low hysteresis
10: Medium hysteresis
11: High hysteresis
27
CMP1PL
Polarity of CMP1 output
This bit is used to select the CMP1 output.
0: Output is not inverted
1: Output is inverted
26:24
CMP1OSEL[2:0]
CMP1 output selection
These bits are used to select the destination of the CMP1 output.
000: No selection
001: TIMER 0 break input
010: TIMER 0 channel0 Input capture
011: TIMER 0 OCPRE_CLR input
100: TIMER1 channel3 input capture
101: TIMER1 OCPRE_CLR input
110: TIMER2 channel0 input capture
111: TIMER2 OCPRE_CLR input
23
WNDEN
Window mode enable
This bit is used to disconnect the CMP1_IP input of CMP1 from PA3 and connect it
to CMP0’s CMP0_IP input.
0: CMP1_IP is connected to PA3
1: CMP1_IP is connected to CMP0_IP
22:20
CMP1MSEL[2:0]
CMP1_M input selection
These bits are used to select the source connected to the CMP1_M input of the
CMP1.
000: VREFINT/4
001: VREFINT /2
010: VREFINT *3/4
011: VREFINT
100: PA4 (DAC0)
101: PA5 (DAC1)
110: PA2
111: Reserved
19:18
CMP1M[1:0]
CMP1 mode
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These bits are used to control the operating mode of the CMP1 adjust the
speed/consumption.
00: High speed / full power
01: Medium speed / medium power
10: Low speed / low power
11: Very-low speed / ultra-low power
17
Reserved
Must be kept at reset value
16
CMP1EN
CMP1 enable
0: CMP1 disabled
1: CMP1 enabled
15
CMP0LK
CMP0 lock
This bit allows to have all control bits of CMP0 as read-only. This bit is write-once.
It can only be cleared by a system reset once It is set by software.
0: CMP_CS[15:0] bits are read-write
1: CMP_CS[15:0] bits are read-only
14
CMP0O
CMP0 output
This is a copy of CMP0 output state, which is read only.
0: Non-inverting input below inverting input and the output is low
1: Non-inverting input above inverting input and the output is high
13:12
CMP0HST[1:0]
CMP0 hysteresis
These bits are used to control the hysteresis level.
00: No hysteresis
01: Low hysteresis
10: Medium hysteresis
11: High hysteresis
11
CMP0PL
Polarity of CMP0 output
This bit is used to select the CMP0 output.
0 : Output is not inverted
1 : Output is inverted
10:8
CMP0OSEL[2:0]
CMP0 output selection
These bits are used to select the destination of the CMP0 output.
000: no selection
001: TIMER 0 break input
010: TIMER 0 channel0 Input capture
011: TIMER 0 OCPRE_CLR input
100: TIMER1 channel3 input capture
101: TIMER1 OCPRE_CLR input
110: TIMER2 channel0 input capture
111: TIMER2 OCPRE_CLR input
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7
Reserved
Must be kept at reset value
6:4
CMP0MSEL[2:0]
CMP0_M input selection
These bits are used to select the source connected to the CMP0_M input of the
CMP0.
000: VREFINT /4
001: VREFINT /2
010: VREFINT *3/4
011: VREFINT
100: PA4 (DAC0)
101: PA5 (DAC1)
110: PA0
111: Reserved
3:2
CMP0M[1:0]
CMP0 mode
These bits are used to control the operating mode of the CMP0 adjust the
speed/consumption.
00: High speed/ full power
01: Medium speed/ medium power
10: Low speed/ low power
11: Very-low speed/ ultra-low power
1
CMP0S
CMP0 switch
This bit is used to closes a switch between CMP0 non-inverting input on PA0 and
PA4 (DAC0) I/O.
0: Switch open
1: Switch closed
0
CMP0EN
CMP0 enable
0: CMP0 disabled
1: CMP0 enabled
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17. Universal synchronous asynchronous receiver
transmitter (USART)
17.1. Introduction
The Universal Synchronous Asynchronous Receiver Transmitter (USART) provides a flexible
serial data exchange interface. Data frames can be transferred in full duplex or half duplex
mode, synchronously or asynchronously through this interface. A programmable baud rate
generator divides the periperial clock (PCLK1 or PCLK2) to produce a dedicated baudrate
clock for the USART transmitter and receiver.
It supports half-duplex single wire synchronous communication, LIN (local interconnection
network), Smartcard Protocol and IrDA (infrared data association) SIR ENDEC specification.
It also supports modem operations (CTS/RTS) and multiprocessor communication.
The USART also supports DMA function for high speed data communication.
17.2. Main features
Full duplex, asynchronous communications
Half duplex single wire communications
NRZ standard format (Mark/Space)
Dual clock domain
– Asynchronous pclk and usart clock
– Baud rate programming independent from the PCLK reprogramming
Programmable baud-rate generator allowing speed up to 9 MBits/s when the clock
frequency is 72 MHz and oversampling is by 8.
Fully programmable serial interface characteristics:
– A data word (8 or 9 bits) LSB or MSB first
– Even, odd or no-parity bit generation/detection
– 1, 1.5 or 2 stop bit generation
Swappable Tx/Rx pin
Configurable data polarity
Auto baud rate detection
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Hardware Modem operations (CTS/RTS) and RS485 drive enable
Configurable multibuffer communication using centralized DMA
Separate enable bits for Transmitter and Receiver
Transfer detection flags:
– Receive buffer full
– Transmit buffer empty
– End of Transmission flags
Parity control:
– Transmits parity bit
– Checks parity of received data byte
Error detection: Overrun, Noise, Frame and Parity error
LIN Break generation and detection
IrDA Support
Synchronous mode and transmitter clock output for synchronous transmission
ISO 7816-3 (T=0 and T=1) compliant smartcard interface
Multiprocessor communication
– Enter into mute mode if address match does not occur
– Wake up from mute mode by idle line or address mark detection
Support for ModBus communication
– Timeout feature
– CR/LF character recognition
Wake up from Deep-sleep mode
– By standard RXNE interrupt
– By WUF interrupt
14 interrupt sources with flags:
– CTS changes
– LIN break detection
– Transmit data register empty
– Transmission complete
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– Receive data register full
– Idle line detected
– Overrun error
– Framing error
– Noise error
– Parity error
– Address/character match
– Receiver timeout interrupt
– End of block interrupt
– Wakeup from Deep-sleep mode
While USART0 is fully implemented, USART1 is only partially implemented with the following
features not supported.
Auto baud rate detection
Smartcard mode
IrDA SIR ENDEC block
LIN mode
Dual clock domain and wakeup from Deep-sleep mode
Receiver timeout interrupt
Modbus communication
17.3. Function description
The interface is externally connected to another device by the main pins listed as following.
Table 17-1. USART important pins description
Pin
Type
Description
RX
Input
Receive Data
TX
Output I/O (single-
wire/smartcard mode)
Transmit Data. high level When enabled but
nothing to be transmitted
CK
Output
Serial clock for synchronous communication
nCTS
Input
Clear to send in Hardware flow control mode
nRTS
Output
Request to send in Hardware flow control mode
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Figure 17-1. USART module block diagram
USART Data Register
CPU/DMA
RW
IrDA
Block
TX
SW_RX
RX
CK Controler
Transmit
Shift
Register
Receive
Shift
Register
USART Control
Registers
CK
Transimit
Controler
Hardware
Flow
Controler
nRTS
nCTS
Receiver
Controler
USART
Address
Wakeup Unit
USART Guard Time
and Prescaler Register
USART Status Register USART Interrupt
Controler
/USARTDIV
/8*(2-OM)
USART Baud
Rate Register
USART CLK
Transmitter
clock
Receiver
clock
17.3.1. USART transmitter
When the transmit enable bit (TEN) in USART_CTL0 register is set, the transmitter clock
pulses are generated by the baud rate generator, and output on the CK pin. Then the serial
bit stream is sent after an idle frame by the transmitter according to the programmed
configuration in the control registers.
In case of transmission corruption, the TEN bit should not be disabled when transmission is
ongoing.
If the data can be written to the USART_TDATA without overwriting the previous one, the TBE
bit is asserted. And it is cleared when the data is written.
If a frame is transmitted and the TBE bit is asserted, the TC bit will be set. An interrupt is
generated if the corresponding interrupt enable bit (TCIE) is set in the USART_CTL0 register.
Refer to the following procedure for the USART transmission:
1. Write the WL bit in USART_CTL0 to set the data bits length.
2. Set the stop bits length in USART_CTL1.
3. Enable DMA (DENT bit) in USART_CTL2 if multibuffer communication is selected.
4. Set the baud rate in USART_BAUD.
5. Set the UEN bit in USART_CTL0 to enable the USART.
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6. Set the TEN bit in USART_CTL0.
7. Wait for the TBE being asserted.
8. Write the data to in the USART_TDATA register.
9. Wait until TC=1 to finish.
It is necessary to wait for the TC bit asserted before disabling the USART or entering the
power saving mode.
Reading the USART_STAT then writing the USART_TDATA can clear the TC bit. And writing
‘0’ directly to TC bit can also clear the TC bit for multibuffer communication
The break frame is sent when the SBKCMD bit is set, and SBKCMD bit is reset after the
transmission.
Table 17-2. Stop bits configuration
Stop bit length (bit)
Description
1
default value
1.5
Smartcard mode
2
normal USART, single-wire and modem modes
Figure 17-2. USART character frame (9 bits data and 1 stop bit)
The MSB bit is taken as the parity bit if parity control is enabled.
If there is even number of ‘1s’ in the data bits (the LSB bits), the parity bit should be ‘0’ (even
parity) or ‘1’ (odd parity).
17.3.2. USART receiver
The receiver receives a bit stream after a valid start pulse has been detected. Overrun, parity,
frame error checking, and line-break detection are also performed.
If a frame is received and the RBNE bit is asserted, the USART_RDATA and associated bits
in USART_STAT can be read. An interrupt is generated if the corresponding interrupt enable
bit (RBNEIE) is set in the USART_CTL0 register.
The RBNE bit must be cleared before the next data arrived, or an overrun error will occur.
In case of reception corruption, the REN bit should not be disabled when reception is ongoing.
The RBNE bit can be cleared by directly reading the USART_RDATA in multibuffer
start bit bit 0 bit 1 bit 2 bit 3 bit 4 bit 5 bit 6 bit 7 bit 8 stop bit start bit
start bit
stop bit start bit
parity bit
Clock
Data Frame
Idle Frame
Break Frame
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communication. DMA read in multibuffer communication can also clear the RBNE bit.
Refer to the following procedure for the USART receiving:
1. Write the WL bit in USART_CTL0 to set the data bits length.
2. Set the stop bits length in USART_CTL1.
3. Enable DMA (DENT bit) in USART_CTL2 if multibuffer communication is selected.
4. Set the baud rate in USART_BAUD.
5. Set the UEN bit in USART_CTL0 to enable the USART.
6. Set the REN bit in USART_CTL0.
17.3.3. Reception errors
An overrun error occurs, if the next data arrived or the previous DMA request has not been
serviced when the RBNE bit is set. The ORERR bit in the USART_STAT register is set.
The internal baud-rate reference clock is used to over sample RX line for data recovery. If a
noise error occurs, the NERR in USART_STAT is set at the rising edge of the RBNE bit and
the invalid data is received from the shift register.
A framing error occurs when the stop bit is not detected at the expected time. If a framing
error occurs, the FERR in USART_STAT is set at the rising edge of the RBNE bit and the
invalid data is received from the shift register.
The three error flag bits can be reset by writting the OREC, NEC and FEC bits in
USART_INTC register respectively.
17.3.4. Baud rate generation
The baud-rate divisor is a 16-bit number consisting of a 12-bit integer and a 4-bit fractional
part. The number formed by these two values is used by the baud-rate generator to determine
the bit period. Having a fractional baud-rate divider allows the USART to generate all the
standard baud rates.
The baud-rate divider (USARTDIV) has the following relationship to the system clock:
In case of oversampling by 16, the equation is:
  

In case of oversampling by 8, the equation is:
  

The choice of the USART clock (UCLK) is done through the Clock Control system (see the
Reset and clock uint(RCU) section). The clock source must be chosen before enabling the
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USART (by setting the UEN bit).
17.3.5. Auto baudrate detection
The USART is able to detect and automatically set the USART_BAUD register value based
on the reception of one character. There are two methods which can be chosen through the
ABDM bits in the USART_CTL1 register. These methods are:
1. The USART will measure the duration of the start bit (falling edge to rising edge). In this
case the receiving pattern should be any character starting with a bit at 1.
2. The USART will measure the duration of the start and of the 1st data bit. The measure
is done falling edge to falling edge, ensuring a better accuracy in the case of slow signal
slopes. In this case, the receiving pattern should be any character starting with 10xx bits.
17.3.6. Multi-processor communication
In multiprocessor communication, the mute mode for the unaddressed receivers is introduced.
During a reception, the target receiver is active to receive the full message contents while the
unintended message recipients are in the mute mode. Idle line detection and address mark
detection can be used to enter or exit the mute mode.
In idle line detection, the USART enters the mute mode and the RWU bit in the USART_STAT
register is set when the MMCMD bit in USART_CMD is asserted. It exits as soon as the idle
frame is detected. The RWU bit in the USART_STAT register is cleared when the IDLEF bit
in USART_STAT is not set.
In address mark detection, the bytes with their MSB bit set are recognized as address byte.
The 4/7 LSB bits in the address byte are the address of the target receiver. The receivers
compare the address byte with the address of their own, then enter or exit the mute mode
(set or reset the RWU bit) according to the result.
17.3.7. ModBus communication
The USART offers basic support for the implementation of Modbus/RTU and Modbus/ASCII
protocols by implementing an end of block detection.
In the Modbus/RTU mode, the end of one block is recognized by an idle line for more than 2
characters time. This function is implemented through the programmable timeout function.
To detect the idle line, the RTEN bit in the USART_CTL1 register and the RTIE in the
USART_CTL0 register must be set. The USART_RT register must be set to the value
corresponding to a timeout of 2 characters time. After the last stop bit is received, when the
receive line is idle for this duration, an interrupt will be generated, informing the software that
the current block reception is completed.
In the Modbus/ASCII mode, the end of a block is recognized by a specific (CR/LF) character
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sequence. The USART manages this mechanism using the character match function by
programming the LF ASCII code in the ADDR field and activating the addrress match interrupt
(AMIE=1). When a LF has been received or can check the CR/LF in the DMA buffer, the
software will be informed.
17.3.8. LIN mode
The local interconnection network mode is enabled by setting the LMEN bit in USART_CTL1.
The CKEN bit in USART_CTL1 and the STPL, SCEN, HDEN, IREN bits in USART_CTL2
should be reset in LIN mode.
The LIN transmission procedure is almost the same as the normal transmission procedure.
The data bits length can only be 8. And the break frame is 13-bit ’0s’.
Break detection is totally independent from the normal USART receiver. So a break can be
detected during the idle state or during a frame.
When the receiver is enabled and a start bit has been detected, the circuit samples the next
bit.
During the break detection, when the framing error occurs, the break detection cancels only
until the RX line becomes high level. Then start bit detection begins. If 10/11 (configured by
the LBLEN bit in USART_CTL1) consecutive bits are detected as ‘0’ before a delimiter
character (high level), the LIN break detection flag is also set in USART_STAT.
Figure 17-3. Frame error detection and break frame detection in LIN mode
17.3.9. Half-duplex communication mode
The half-duplex communication mode is enabled by setting the HDEN bit in USART_CTL2.
The LMEN, CKEN bits in USART_CTL1 and SCEN, IREN bits in USART_CTL2 should be
reset in half-duplex communication mode.
Only one wire is used in half-duplex mode. The TX and RX pins are connected together
internally. The TX pin should be configured as IO pin. The conflicts should be controlled by
the software. When the TEN bit is set, the data in the data register will be sent.
DATA0 DATA1 BREAK FRAME DATA2 DATA3
data length
RX Line
FE
LBDF
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17.3.10. Synchronous mode
The USART can be used for full-duplex synchronous serial communications only in master
mode, by setting the CKEN bit in USART_CTL1. The LMEN bit in USART_CTL1 and SCEN,
HDEN, IREN bits in USART_CTL2 should be reset in synchronous mode. The CK pin is the
synchronous USART transmitter clock output, and can be only activated when the TEN bit is
enabled. No clock pulse will be sent to the CK pin during the start bit and stop bit transmission.
The CLEN bit in USART_CTL1 can be used to determine whether the clock is output or not
during the LSB (address index) bit transmission. The clock output is also not activated during
idle and break frame sending. The CPH bit in USART_CTL1 can be used to determine
whether data is captured on the first or the second clock edge. The CPL bit in USART_CTL1
can be used to configure the clock polarity in the USART Synchronous Mode idle state.
These 3 bits (CPL, CPH, CLEN) should not be changed while the transmitter or the receiver
is enabled
The clock is synchronized with the data transmitted. The receiver in synchronous mode
samples the data on the transmitter clock without any oversampling.
Figure 17-4. Example of USART in synchronous mode
USART
(master mode)
RX
TX
CK
Device
(slave mode)
Clock input
Data input
Data output
Figure 17-5. 8-bit format USART synchronous waveform (CLEN=1)
CLK2(CPL=1)
CLK3(CPL=0)
CLK4(CPL=1)
Master data output
Master data input
CPH=0
CPH=1
Idle or preceding transmission Idle or next transmission
Start
Stop
bit4 bit5 bit6 bit7bit0 bit1 bit2 bit3
bit4 bit5 bit6 bit7bit0 bit1 bit2 bit3
CLK1(CPL=0)
17.3.11. Smartcard (ISO7816) mode
The smartcard mode is an asynchronous mode, which is enabled by setting the SCEN bit in
USART_CTL2. The LMEN bit in USART_CTL1 and HDEN, IREN bits in USART_CTL2 should
be reset in smartcard mode.
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A clock is provided to the smartcard if the CKEN bit is set. The clock can be divided for other
use.
The frame consists of 1 start bit, 9 data bits (1 parity bit included) and 1.5 stop bits.
The smartcard mode is a half-duplex communication protocol. When connected to a
smartcard, the TX pin must be configured as open drain and drives a bidirectional line that is
also driven by the smartcard.
T=0 mode
Figure 17-6. ISO7816-3 frame format
01234567
01234567
0.5 bit 1 bit
S
S
ISO 7816-3 frame without parity error
ISO 7816-3 frame with parity error
P
P
Comparing to the time in normal operation, the transmission time from transmit shift register
to the TX pin is delayed half baud clock, and the TC flag assertion time delayed a certain
value wrote in the guard time register. The USART can automaticly re-send data according to
the protocol by SCRTNUM times. At the end of reception of the last repeated character the
TC bit is set without gardtime immediately. The USART will stop transmitting and signal the
error as a framing error if it continues receiving the NKEN after the programmed number of
retries. The TXFCMD bit in the USART_CMD register can be used to clear the TBE bit.
During USART reception, the TX line is pulled low for a baud clock after finishing receiving
the frame if a parity error is detected. This signal is the ‘NKEN’ signal to smartcard. Then a
frame error occurred in smartcard side. The RBNE/receive DMA request is not activated if the
received character is erroneous. According to the protocol, the smartcard can resend the data.
The USART stops transmitting the NKEN and signals the error as a parity error if the received
character is still erroneous after the maximum number of retries specified in the SCARNUM
bit field.
The ‘NKEN’ signal will be sent to the USART if the NKEN bit in USART_CTL2 is set. And the
USART will not take the ‘NKEN’ signal as the start bit.
The idle frame and break frame do not apply for the smartcard mode.
T=1 mode (block mode)
In T=1 (block) mode, the NKEN bit in the USART_CTL2 register should be cleared to
deactivate the parity error transmission.
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When requesting a read from the smartcard, the USART_RT register should be programmed
with the BWT (block wait time) - 11 value and RBNEIE must be set. A timeout interrupt will be
generated, if no answer is received from the card before the expiration of this period. If the
first character is received before the expiration of the period, it is signaled by the RBNE
interrupt. If DMA is used to read from the smartcard in block mode, the DMA must be enabled
only after the first received byte.
In order to allow the automatic check of the maximum wait time between two consecutive
characters, the USART_RT register must be programmed to the CWT (character wait time) -
11 value, which is expressed in baudtime units, after the reception of the first character (RBNE
interrupt). The USART signals to the software through the RT flag and interrupt (when RTIE
bit is set), if the smartcard doesn’t send a new character in less than the CWT period after the
end of the previous character.
The USART uses a block length counter, which is reset when the USART is transmitting
(TBE=0), to count all the characters received. The length of the block, which must be
programmed to the BL field in the USART_RT register, is communicated by the smartcard in
the third byte of the block (prologue field). This register field must be programmed to the
minimum value (0x0), before the start of the block, when using DMA mode. With this value,
an interrupt is generated after the 4th received character. The software must read the third
byte as block length from the receive buffer.
In interrupt driven receive mode, the length of the block may be checked by software or by
programming the BL value. However, before the start of the block, the maximum value of BL
(0xFF) may be programmed. The real value will be programmed after the reception of the
third character.
The total block length (including prologue, epilogue and information fields) equals BL+4. The
end of the block is signaled to the software through the EBF flag and interrupt (when EBIE bit
is set). The RT interrupt may occur in case of an error in the block length.
Direct and inverse convention
The smartcard protocol defines two conventions: direct and inverse.
The direct convention is defined as: LSB first, logical bit value of 1 corresponds to H state of
the line and parity is even. In this case, the following control bits must be programmed:
MSBF=0, DINV=0 (default values).
The inverse convention is defined as: MSB first, logical bit value 1 corresponds to an L state
on the signal line and parity is even. In this case, the following control bits must be
programmed: MSBF=1, DINV=1.
17.3.12. IrDA SIR ENDEC mode
The IrDA mode is enabled by setting the IREN bit in USART_CTL2. The LMEN, STPL, CKEN
bits in USART_CTL1 and HDEN, SCEN bits in USART_CTL2 should be reset in IrDA mode.
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In IrDA SIR physical layer, an infrared light pulse (a Return to Zero signal) represent the logic
‘0’. The pulse width should be 3/16 of a bit period. The IrDA could not detect the pulse if the
pulse width is less than 1 PSC clock. While it can detect some pulse by chance if the pulse
width is greater than 1 but smaller than 2 times PSC clock.
The USART data frame is modulated in SIR Transmit encoder. The modulated signal is
transmitted by the infrared LED. The baud rate should not be larger than 115200 for the
encoder.
The infrared detector receives the modulated signal and outputs the data frame decoded. The
polarity of modulated signal transmitted by the encoder is opposite to that received by the
decoder. Then the decoder input is usually the high level and a start bit is decoded if the input
signal is low.
The transmission and the reception should not be carried out at the same time in the IrDA
SIR ENDEC block.
For power saving mode:
Transmitter: The pulse width can be 3 times the low-power baud rate.
Receiver: The same as normal mode.
Figure 17-7. IrDA SIR ENDEC module
USART
Transmit
Encoder
Receive
Decoder
SIR MODULE
TX
RX
USART_TX
IrDA_OUT
IrDA_IN
USART_RX
IREN
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Figure 17-8. IrDA data modulation
17.3.13. Hardware flow control
Using the nCTS input and the nRTS output to control the serial data flow is called hardware
flow control. The RTS flow control is enabled by writing ‘1’ to the RTSEN bit in USART_CTL2
and the CTS flow control is enabled by write ‘1’ to the CTSEN bit in USART_CTL2.
Figure 17-9. Hardware flow control between two USARTs
USART 1
TX module
RX module
USART 2
RX module
TX module
TX RX
nCTS nRTS
RX TX
nRTS nCTS
RTS flow control
USART receiver can receive data only when the nRTS signal is low, and the signal does not
go high until the data frame reception is finished. The next reception occurs when the nRTS
signal goes low again. The signal keeps high when the receive register is full.
CTS flow control
If the TBE bit in USART_STAT is ‘0’ and the nCTS signal is low, the transmitter transmits the
data frame. When the nCTS signal goes high during a transmission, the transmitter stops
after the current transmission is accomplished.
start bit 1 0 1 0 1 1 0 0 0 1 0
stop bit
stop bit
start bit 1 0 1 0 1 1 0 0 0 1 0
TX
IrDA_OUT
IrDA_IN
RX
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Figure 17-10. Hardware flow control
RS485 Driver Enable
The driver enable feature, which is enabled by setting bit DEM in the USART_CTL2 control
register, allows the user to activate the external transceiver control, through the DE (Driver
Enable) signal. The assertion time, which is programmed using the DEA [4:0] bits field in the
USART_CTL0 control register, is the time between the activation of the DE signal and the
beginning of the START bit. The de-assertion time, which is programmed using the DED [4:0]
bits field in the USART_CTL0 control register, is the time between the end of the last stop bit
and the de-activation of the DE signal. The polarity of the DE signal can be configured using
the DEP bit in the USART_CTL2 control register.
17.3.14. DMA requests
DMA can be used for USART continuously communication. The DENT bit in USART_CTL2 is
used to enable the DMA transmission, and the DENR bit in USART_CTL2 is used to enable
the DMA reception.
DMA transmission configuration:
1. Configuring the DMA registers, which the destination address (USART_TDATA register
address), the source address (memory address), the total number of bytes to be
transferred, channel priority, DMA interrupts are written to.
2. Writing ‘0’ to the TCC bit in USART_INTC.
3. Writing ‘1’ to the DENT bit in the DMA control register to enable the DMA channel.
The TC flag in USART_STAT is set later than the time when the FTFIF flag is set in DMA_INTF.
It remains reset during the data transfers, and is set when the USART communication finished.
Entering the Deep-sleep mode or disabling the USART will lead to the transfer corruption
when the TC bit is not set.
DMA reception configuration: configuring the DMA registers, which the destination address
(memory address), the source address (USART_RDATA register address), the total number
start startstop stop
idle
data 1 data 2
RTS flow control
CTS flow control
data 1 data 2
stop start stop
startstop idle
empty data 2 empty data 3 empty
idle
nRTS
RX
nCTS
USART_DR
TX
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of bytes to be transferred, channel priority, DMA interrupts are written to.
The RBNE event occurs as soon as the data is received.
17.3.15. Wakeup from Deep-sleep mode
The USART is able to wake up the MCU from Deep-sleep mode by the standard RBNE
interrupt or the WUM interrupt.
The UESM bit must be set and the USART clock must be set to IRC8M or LXTAL (refer to the
reset and clock unit RCU section).
When using the standard RBNE interrupt, the RBNEIE bit must be set before entering Deep-
sleep mode.
When using the WUIE interrupt, the soure of WUIE interrupt may be selected through the
WUM bit fields.
DMA must be disabled before entering Deep-sleep mode. Before entering Deep-sleep mode,
software must check that the USART is not performing a transfer, by checking the BSY flag
in the USART_STAT register. The REA bit must be checked to ensure the USART is actually
enabled.
When the wakeup event is detected, the WUF flag is set by hardware and a wakeup interrupt
is generated if the WUIE bit is set, independently of whether the MCU is in stop or active
mode.
17.3.16. USART interrupts
The USART interrupt events and flags are listed in the table below.
Table 17-3. USART interrupt requests
Interrupt event
Event flag
Enable Control bit
Transmit data register empty
TBE
TBEIE
CTS flag
CTSF
CTSIE
Transmission complete
TC
TCIE
Received data ready to be read
RBNE
RBNEIE
Overrun error detected
ORERR
Idle line detected
IDLEF
IDLEIE
Parity error flag
PERR
PERRIE
Break detected flag in LIN
mode
LBDF
LBDIE
Reception Errors (Noise flag,
overrun error, framing error) in
DMA reception
NERR or ORERR or FERR
EIE
Character match
AMF
AMIE
Receiver timeout error
RTF
RTIE
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Interrupt event
Event flag
Enable Control bit
End of Block
EBF
EBIE
Wakeup from Deep-sleep mode
WUF
WUIE
All of the interrupt events are ORed together before being sent to the interrupt controller, so
the USART can only generate a single interrupt request to the controller at any given time.
Software can service multiple interrupt events in a single interrupt service routine
Figure 17-11. USART interrupt mapping diagram
IDLE
IDLEIE
RBNE
RBNEIE
ORE
RBNEIE
PE
PEIE
WUF
WUIE
LBDF
LBDIE
AMF
AMIE
RTF
RTIE
EBF
EBIE
FE
NE
ORE EIE OR
TC
TCIE
TBE
TBEIE
CTSF
CTSIE
USART_INT
17.4. USART registers
17.4.1. Control register 0 (USART_CTL0)
Address offset: 0x00
Reset value: 0x0000_0000
This register has to be accessed by word (32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
EBIE
RTIE
DEA[4:0]
DED[4:0]
rw
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
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OVSMOD
AMIE
MEN
WL
WM
PCEN
PM
PERRIE
TBEIE
TCIE
RBNEIE
IDLEIE
TEN
REN
UESM
UEN
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31:28
Reserved
Must be kept at reset value
27
EBIE
End of Block interrupt enable
0: End of Block interrupt is disabled
1: End of Block interrupt is enabled
This bit is reserved in USART1.
26
RTIE
Receiver timeout interrupt enable
0: Receiver timeout interrupt is disabled
1: Receiver timeout interrupt is enabled
This bit is reserved in USART1.
25:21
DEA[4:0]
Driver Enable assertion time
These bits are used to define the time between the activation of the DE (Driver
Enable) signal and the beginning of the start bit. It is expressed in sample time units
(1/8 or 1/16 bit time), which are configured by the OVSMOD bit.
This bit field cannot be written when the USART is enabled (UEN=1).
20:16
DED[4:0]
Driver Enable deassertion time
These bits are used to define the time between the end of the last stop bit, in a
transmitted message, and the de-activation of the DE (Driver Enable) signal. It is
expressed in sample time units (1/8 or 1/16 bit time), which are configured by the
OVSMOD bit.
This bit field cannot be written when the USART is enabled (UEN=1).
15
OVSMOD
Oversample mode
0: Oversampling by 16
1: Oversampling by 8
This bit must be kept cleared in LIN, IrDA and smartcard modes.
This bit field cannot be written when the USART is enabled (UEN=1).
14
AMIE
ADDR match interrupt enable
0: ADDR match interrupt is disabled
1: ADDR match interrupt is enabled
13
MEN
Mute mode enable
0: Mute mode disabled
1: Mute mode enabled
12
WL
Word length
0: 8 Data bits,
1: 9 Data bits
This bit field cannot be written when the USART is enabled (UEN=1).
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11
WM
Wakeup method in mute mode
0: Idle Line
1: Address Mark
This bit field cannot be written when the USART is enabled (UEN=1).
10
PCEN
Parity control enable
0: Parity control disabled
1: Parity control enabled
This bit field cannot be written when the USART is enabled (UEN=1).
9
PM
Parity mode
0: Even parity
1: Odd parity
This bit field cannot be written when the USART is enabled (UEN=1).
8
PERRIE
Parity error interrupt enable
0: Parity error interrupt is disabled
1: An interrupt will occur whenever the PERR bit is set in USART_STAT.
7
TBEIE
Transmitter register empty interrupt enable
0: Interrupt is inhibited
1: An interrupt will occur whenever the TBE bit is set in USART_STAT
6
TCIE
Transmission complete interrupt enable
0: Transmission complete interrupt is disabled
1: An interrupt will occur whenever the TC bit is set in USART_STAT.
5
RBNEIE
Read data buffer not empty interrupt and overrun error interrupt enable
0: Read data register not empty interrupt and overrun error interrupt disabled
1: An interrupt will occur whenever the ORERR bit is set or the RBNE bit is set in
USART_STAT.
4
IDLEIE
IDLE line detected interrupt enable
0: IDLE line detected interrupt disabled
1: An interrupt will occur whenever the IDLEF bit is set in USART_STAT.
3
TEN
Transmitter enable
0: Transmitter is disabled
1: Transmitter is enabled
2
REN
Receiver enable
0: Receiver is disabled
1: Receiver is enabled and begins searching for a start bit
1
UESM
USART enable in Deep-sleep mode
0: USART not able to wake up the MCU from Deep-sleep mode.
1: USART able to wake up the MCU from Deep-sleep mode. Providing that the
clock source for the USART must be IRC8M or LXTAL.
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This bit is reserved in USART1.
0
UEN
USART enable
0: USART prescaler and outputs disabled
1: USART prescaler and outputs enabled
17.4.2. Control register 1 (USART_CTL1)
Address offset: 0x04
Reset value: 0x0000_0000
This register has to be accessed by word (32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
ADDR[7:0]
RTEN
ABDM[1:0]
ABDEN
MSBF
DINV
TINV
RINV
rw
rw
rw
rw
rw
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
STRP
LMEN
STB[1:0]
CKEN
CPL
CPH
CLEN
Reserved
LBDIE
LBLEN
ADDM
Reserved
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31:24
ADDR[7:0]
Address of the USART terminal
These bits give the address of the USART terminal.
In multiprocessor communication during mute mode or Deep-sleep mode, this is used
for wakeup with address mark detection. The received frame, the MSB of which is
equal to 1, will be compared to these bits. When the ADDM bit is reset, only the
ADDR[3:0] bits are used to compare.
In normal reception, these bits are also used for character detection. The whole
received character (8-bit) is compared to the ADD[7:0] value and AMF flag is set on
matching.
This bit field cannot be written when both reception (REN=1) and USART (UEN=1)
are enabled.
23
RTEN
Receiver timeout enable
0: Receiver timeout function disabled
1: Receiver timeout function enabled
This bit is reserved in USART1.
22:21
ABDM[1:0]
Auto baud rate mode
00: Falling edge to rising edge measurement (measurement of the start bit)
01: Falling edge to falling edge measurement (the received frame must be in a Start
10xxxxxx frame format)
10: Reserved.
11: Reserved
This bit field cannot be written when the USART is enabled (UEN=1).
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This bit is reserved in USART1.
20
ABDEN
Auto baud rate enable
0: Auto baud rate detection is disabled
1: Auto baud rate detection is enabled
This bit is reserved in USART1.
19
MSBF
Most significant bit first
0: Data is transmitted/received with the LSB first
1: Data is transmitted/received with the MSB first
This bit field cannot be written when the USART is enabled (UEN=1).
18
DINV
Data bit level inversion
0: Data bit signal values are not inverted
1: Data bit signal values are inverted
This bit field cannot be written when the USART is enabled (UEN=1).
17
TINV
TX pin level inversion
0: TX pin signal values are not inverted
1: TX pin signal values are inverted
This bit field cannot be written when the USART is enabled (UEN=1).
16
RINV
RX pin level inversion
0: RX pin signal values are not inverted
1: RX pin signal values are inverted
This bit field cannot be written when the USART is enabled (UEN=1).
15
STRP
Swap TX/RX pins
0: The TX and RX pins functions are not swapped
1: The TX and RX pins functions are swapped
This bit field cannot be written when the USART is enabled (UEN=1).
14
LMEN
LIN mode enable
0: LIN mode disabled
1: LIN mode enabled
This bit field cannot be written when the USART is enabled (UEN=1).
This bit is reserved in USART1.
13:12
STB[1:0]
STOP bits length
00: 1 Stop bit
01: Reserved
10: 2 Stop bits
11: 1.5 Stop bit
This bit field cannot be written when the USART is enabled (UEN=1).
11
CKEN
CK pin enable
0: CK pin disabled
1: CK pin enabled
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This bit field cannot be written when the USART is enabled (UEN=1).
This bit is reserved in USART1.
10
CPL
Clock polarity
0: Steady low value on CK pin outside transmission window in synchronous mode
1: Steady high value on CK pin outside transmission window in synchronous mode
This bit field cannot be written when the USART is enabled (UEN=1).
9
CPH
Clock phase
0: The first clock transition is the first data capture edge in synchronous mode
1: The second clock transition is the first data capture edge in synchronous mode
This bit field cannot be written when the USART is enabled (UEN=1).
8
CLEN
CK length
0: The clock pulse of the last data bit (MSB) is not output to the CK pin in
synchronous mode
1: The clock pulse of the last data bit (MSB) is output to the CK pin in synchronous
mode
This bit field cannot be written when the USART is enabled (UEN=1)
7
Reserved
Must be kept at reset value
6
LBDIE
LIN break detection interrupt enable
0: LIN break detection interrupt is disabled
1: An interrupt will occur whenever the LBDF bit is set in USART_STAT
This bit is reserved in USART1.
5
LBLEN
LIN break frame length
0: 10 bit break detection
1: 11 bit break detection
This bit field cannot be written when the USART is enabled (UEN=1).
This bit is reserved in USART1.
4
ADDM
Address detection mode
This bit is used to select between 4-bit address detection and full-bit address
detection.
0: 4-bit address detection
1: full-bit address detection. In 7-bit, 8-bit and 9-bit data modes, the address
detection is done on 6-bit, 7-bit and 8-bit address (ADD[5:0], ADD[6:0] and
ADD[7:0]) respectively
This bit field cannot be written when the USART is enabled (UEN=1).
3:0
Reserved
Must be kept at reset value
17.4.3. Control register 2 (USART_CTL2)
Address offset: 0x08
Reset value: 0x0000_0000
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This register has to be accessed by word (32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
WUIE
WUM[1:0]
SCRTNUM[2:0]
Reserved
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
DEP
DEM
DDRE
OVRD
OSB
CTSIE
CTSEN
RTSEN
DENT
DENR
SCEN
NKEN
HDEN
IRLP
IREN
ERRIE
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31:23
Reserved
Must be kept at reset value
22
WUIE
Wakeup from Deep-sleep mode interrupt enable
0: Wakeup from Deep-sleep mode interrupt is disabled
1: Wakeup from Deep-sleep mode interrupt is enabled
This bit is reserved in USART1.
21:20
WUM[1:0]
Wakeup mode from Deep-sleep mode
These bits are used to specify the event which activates the WU (Wakeup from
Deep-sleep mode flag) in the USART_STAT register.
00: WU active on address match, which is defined by ADDR and ADDM
01: Reserved
10: WU active on Start bit
11: WU active on RBNE
This bit field cannot be written when the USART is enabled (UEN=1).
This bit is reserved in USART1.
19:17
SCRTNUM[2:0]
Smartcard auto-retry number
In smartcard mode, these bits specify the number of retries in transmit and receive.
In transmission mode, a transmission error (FERR bit set) will occur after this
number of automatic retransmission retries.
In reception mode, reception error (RBNE and PERR bits set) will occur after this
number or erroneous reception trials.
When these bits are configured as 0x0, there will be no automatic retransmission in
transmit mode.
This bit field is only can be cleared to 0 when the USART is enabled (UEN=1), to
stop retransmission.
This bit is reserved in USART1.
16
Reserved
Must be kept at reset value
15
DEP
Driver enable polarity mode
0: DE signal is active high
1: DE signal is active low
This bit field cannot be written when the USART is enabled (UEN=1).
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14
DEM
Driver enable mode
This bit is used to activate the external transceiver control, through the DE signal,
which is output on the RTS pin.
0: DE function is disabled
1: DE function is enabled
This bit field cannot be written when the USART is enabled (UEN=1).
13
DDRE
Disable DMA on reception error
0: DMA is not disabled in case of reception error. The DMA request is not asserted
to make sure the erroneous data is not transferred, but the next correct received
data will be transferred.The RBNE is kept 0 to prevent overrun, but the
corresponding error flag is set. This mode can be used in Smartcard mode
1: DMA is disabled following a reception error. The DMA request is not asserted
until the error flag is cleared. The RBNE flag and corresponding error flag will be
set. The software must first disable the DMA request (DMAR = 0) or clear RBNE
before clearing the error flag
This bit field cannot be written when the USART is enabled (UEN=1).
12
OVRD
Overrun Disable
0: Overrun functionality is enabled. The ORERR error flag will be set when received
data is not read before receiving new data, and the new data will be lost
1: Overrun functionality is disabled. The ORERR error flag will not be set when
received data is not read before receiving new data, and the new received data
overwrites the previous content of the USART_RDATA register
This bit field cannot be written when the USART is enabled (UEN=1).
11
OSB
One sample bit method
0: Three sample bit method
1: One sample bit method
This bit field cannot be written when the USART is enabled (UEN=1).
10
CTSIE
CTS interrupt enable
0: CTS interrupt is disabled
1: An interrupt will occur whenever the CTS bit is set in USART_STAT
9
CTSEN
CTS enable
0: CTS hardware flow control disabled
1: CTS hardware flow control enabled
This bit field cannot be written when the USART is enabled (UEN=1).
8
RTSEN
RTS enable
0: RTS hardware flow control disabled
1: RTS hardware flow control enabled, data can be requested only when there is
space in the receive buffer
This bit field cannot be written when the USART is enabled (UEN=1).
7
DENT
DMA enable for transmission
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0: DMA mode is disabled for transmission
1: DMA mode is enabled for transmission
6
DENR
DMA enable for reception
0: DMA mode is disabled for reception
1: DMA mode is enabled for reception
5
SCEN
Smartcard mode enable
0: Smartcard Mode disabled
1: Smartcard Mode enabled
This bit field cannot be written when the USART is enabled (UEN=1).
This bit is reserved in USART1.
4
NKEN
NKEN enable in Smartcard mode
0: Disable NKEN transmission when parity error
1: Enable NKEN transmission when parity error
This bit field cannot be written when the USART is enabled (UEN=1).
This bit is reserved in USART1.
3
HDEN
Half-duplex enable
0: Half duplex mode is disabled
1: Half duplex mode is enabled
This bit field cannot be written when the USART is enabled (UEN=1).
2
IRLP
IrDA low-power
0: Normal mode
1: Low-power mode
This bit field cannot be written when the USART is enabled (UEN=1).
1
IREN
IrDA mode enable
0: IrDA disabled
1: IrDA enabled
This bit field cannot be written when the USART is enabled (UEN=1).
This bit is reserved in USART1.
0
ERRIE
Error interrupt enable
0: Error interrupt disabled
1: An interrupt will occur whenever the FERR bit or the ORERR bit or the NERR bit
is set in USART_STAT in multibuffer communication
17.4.4. Baud rate generator register (USART_BAUD)
Address offset: 0x0C
Reset value: 0x0000_0000
This register has to be accessed by word (32-bit)
This register cannot be written when the USART is enabled (UEN=1)
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31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
INTDIV [11:0]
FRADIV [3:0]
rw
rw
Bits
Fields
Descriptions
31:16
Reserved
Must be kept at reset value
15:4
INTDIV [11:0]
Integer part of baud-rate divider
DIV_INT[11:0] = INTDIV [11:0]
3:0
FRADIV [3:0]
Fraction part of baud-rate divider
If OVSMOD = 0, USARTDIV [3:0] = FRADIV [3:0];
If OVSMOD = 1, USARTDIV [3:1] = FRADIV [2:0], FRADIV [3] must be reset.
17.4.5. Prescaler and guard time configuration register (USART_GP)
Address offset: 0x10
Reset value: 0x0000_0000
This register has to be accessed by word (32-bit)
This register cannot be written when the USART is enabled (UEN=1)
This register is reserved in USART1
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
GUAT[7:0]
PSC[7:0]
rw
rw
Bits
Fields
Descriptions
31:16
Reserved
Must be kept at reset value
15:8
GUAT[7:0]
Guard time value in smartcard mode
7:0
PSC[7:0]
Prescaler value for dividing the system clock
In IrDA Low-power mode, the division factor is the prescaler value.
00000000: Reserved - do not program this value
00000001: divides the source clock by 1
00000010: divides the source clock by 2
...
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In IrDA normal mode.
00000001: can be set this value only
In smartcard mode, the prescaler value for dividing the system clock is stored in
PSC[4:0] bits. And the bits of PSC[7:5] must be kept at reset value. The division factor
is twice as the prescaler value.
00000: Reserved - do not program this value
00001: divides the source clock by 2
00010: divides the source clock by 4
00011: divides the source clock by 6
...
17.4.6. Receiver timeout register (USART_RT)
Address offset: 0x14
Reset value: 0x0000_0000
This register has to be accessed by word (32-bit)
This bit is reserved in USART1
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
BL[7:0]
RT[23:16]
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RT[15:0]
rw
Bits
Fields
Descriptions
31:24
BL[7:0]
Block Length
These bits specify the block length in smartcard T=1 Reception. Its value equals the
number of information characters + the length of the Epilogue Field (1-LEC/2-CRC)
- 1.
This value, which must be programmed only once per received block, can be
programmed after the start of the block reception (using the data from the LEN
character in the Prologue Field). The block length counter is reset when TBE=0 in
smartcard mode.
In other modes, when REN=0 (receiver disabled) and/or when the EOBCF bit is
written to 1, the Block length counter is reset.
23:0
RT[23:0]
Receiver timeout threshold
These bits are used to specify receiver timeout value in terms of number of baud
clocks.
In standard mode, the RTF flag is set if no new start bit is detected for more than
the RT value after the last received character.
In smartcard mode, the CWT and BWT are implemented by this value. In this case,
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the timeout measurement is started from the start bit of the last received character.
These bits can be written on the fly. The RTF flag will be set if the new value is
lower than or equal to the counter. These bits must only be programmed once per
received character.
17.4.7. Command register (USART_CMD)
Address offset: 0x18
Reset value: 0x0000_0000
This register has to be accessed by word (32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
TXFCMD
RXFCMD
MMCMD
SBKCMD
ABDCMD
w
w
w
w
w
Bits
Fields
Descriptions
31:5
Reserved
Must be kept at reset value
4
TXFCMD
Transmit data flush request
Writing 1 to this bit sets the TBE flag, to discard the transmit data.
This bit is reserved in USART1.
3
RXFCMD
Receive data flush command
Writing 1 to this bit clears the RBNE flag to discard the received data without
reading it.
2
MMCMD
Mute mode command
Writing 1 to this bit makes the USART into mute mode and sets the RWU flag.
1
SBKCMD
Send break command
Writing 1 to this bit sets the SBKF flag and make the USART send a BREAK frame,
as soon as the transmit machine is idle.
0
ABDCMD
Auto baudrate detection command
Writing 1 to this bit issues an automatic baud rate measurement command on the
next received data frame and resets the ABDF flag in the USART_STAT.
This bit is reserved in USART1
17.4.8. Status register (USART_STAT)
Address offset: 0x1C
Reset value: 0x0000_00C0
This register has to be accessed by word (32-bit)
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31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
REA
TEA
WUF
RWU
SBF
AMF
BSY
r
r
r
r
r
r
r
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
ABDF
ABDE
Reserved
EBF
RTF
CTS
CTSF
LBDF
TBE
TC
RBNE
IDLEF
ORERR
NERR
FERR
PERR
r
r
r
r
r
r
r
r
r
r
r
r
r
r
r
Bits
Fields
Descriptions
31:23
Reserved
Must be kept at reset value
22
REA
Receive enable acknowledge flag
This bit, which is set/reset by hardware, reflects the receive enable state of the
USART core logic.
0: The USART core receiving logic has not been enabled
1: The USART core receiving logic has been enabled
21
TEA
Transmit enable acknowledge flag
This bit, which is set/reset by hardware, reflects the transmit enable state of the
USART core logic.
0: The USART core transmitting logic has not been enabled
1: The USART core transmitting logic has been enabled
20
WUF
Wakeup from Deep-sleep mode flag
0: No wakeup from Deep-sleep mode
1: Wakeup from Deep-sleep mode. An interrupt is generated if WUFIE=1 in the
USART_CTL2 register and the MCU is in Deep-sleep mode.
This bit is set by hardware when a wakeup event, which is defined by the WUS bit
field, is detected.
Cleared by writing a 1 to the WUC in the USART_INTC register.
This bit can also be cleared when UESM is cleared.
This bit is reserved in USART1.
19
RWU
Receiver wakeup from mute mode.
This bit is used to indicate if the USART is in mute mode.
0: Receiver in active mode
1: Receiver in mute mode
It is cleared/set by hardware when a wakeup/mute sequence (address or IDLE) is
recognized, which is selected by the WAKE bit in the USART_CTL0 register.
This bit can only be set by writing 1 to the MMCMD bit in the USART_CMD register
when wakeup on IDLE mode is selected.
18
SBF
Send break flag
0: No break character is to be transmitted
1: Break character will be transmitted
This bit indicates that a send break character was requested.
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Set by software, by writing 1 to the SBKCMD bit in the USART_CMD register.
Clear by hardware during the stop bit of break transmission.
17
AMF
ADDR match flag
0: ADDR do not match the received character
1: ADDR matches the received character, An interrupt is generated if AMIE=1in the
USART_CTL0 register.
Set by hardware, when the character defined by ADDR [7:0] is received.
Cleared writing 1 to the AMC in the USART_INTC register.
16
BSY
Busy flag
0: USART reception path is idle
1: USART reception path is working
15
ABDF
Auto baudrate detection flag
0: No auto baudrate detection complete
1: Auto baudrate detection complete
Set by hardware when the automatic baud rate has been completed.
Cleared by writing 1 to the ABDCMD in the USART_CMD register, to request a new
auto baudrate detection.
This bit is reserved in USART1.
14
ABDE
Auto baudrate detection error
0: No auto baudrate detection error occured
1: Auto baudrate detection error occured
Set by hardware if the baud rate out of range or character comparison failed
Cleared by software, by writing 1 to the ABDRQ bit in the USART_CTL2 register.
This bit is reserved in USART1
13
Reserved
Must be kept at reset value
12
EBF
End of block flag
0: End of Block not reached
1: End of Block (number of characters) reached. An interrupt is generated if the
EBIE=1 in the USART_CTL1 register
Set by hardware when the number of received bytes (from the start of the block,
including the prologue) is equal or greater than BLEN + 4.
Cleared by writing 1 to EBC bit in USART_INTC register.
This bit is reserved in USART1.
11
RTF
Receiver timeout flag
0: Timeout value not reached
1: Timeout value reached without any data reception. An interrupt is generated if
RTIE bit in the USART_CTL1 register is set.
Set by hardware when the RT value, programmed in the USART_RT register has
lapsed without any communication.
Cleared by writing 1 to RTC bit in USART_INTC register.
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The timeout corresponds to the CWT or BWT timings in smartcard mode.
This bit is reserved in USART1
10
CTS
CTS level
This bit equals to the inverted level of the nCTS input pin.
0: nCTS input pin is in high level
1: nCTS input pin is in low level
9
CTSF
CTS change flag
0: No change occurred on the nCTS status line
1: A change occurred on the nCTS status line. An interrupt will occur if the CTSIE
bit is set in USART_CTL2
Set by hardware when the nCTS input toggles.
Cleared by writing 1 to CTSC bit in USART_INTC register.
8
LBDF
LIN break detected flag
0: LIN Break is not detected
1: LIN Break is detected. An interrupt will occur if the LBDIE bit is set in
USART_CTL1
Set by hardware when the LIN break is detected.
Cleared by writing 1 to LBDC bit in USART_INTC register.
This bit is reserved in USART1.
7
TBE
Transmit data register empty
0: Data is not transferred to the shift register
1: Data is transferred to the shift register. An interrupt will occur if the TBEIE bit is
set in USART_CTL0
Set by hardware when the content of the USART_TDATA register has been
transferred into the transmit shift register or writing 1 to TXFCMD bit of the
USART_CMD register.
Cleared by a write to the USART_TDATA.
6
TC
Transmission completed
0: Transmission is not completed
1: Transmission is complete. An interrupt will occur if the TCIE bit is set in
USART_CTL0.
Set by hardware if the transmission of a frame containing data is completed and if
the TBE bit is set.
Cleared by writing 1 to TCC bit in USART_INTC register.
5
RBNE
Read data buffer not empty
0: Data is not received
1: Data is received and ready to be read. An interrupt will occur if the RBNEIE bit is
set in USART_CTL0.
Set by hardware when the content of the receive shift register has been transferred
to the USART_RDATA.
Cleared by reading the USART_TDATA or writing 1 to RXFCMD bit of the
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USART_CMD register.
4
IDLEF
IDLE line detected flag
0: No Idle Line is detected
1: Idle Line is detected. An interrupt will occur if the IDLEIE bit is set in
USART_CTL0
Set by hardware when an Idle Line is detected. It will not be set again until the
RBNE bit has been set itself.
Cleared by writing 1 to IDLEC bit in USART_INTC register.
3
ORERR
Overrun error
0: No Overrun error is detected
1: Overrun error is detected. An interrupt will occur if the RBNEIE bit is set in
USART_CTL0. In multibuffer communication, an interrupt will occur if the ERRIE bit
is set in USART_CTL2.
Set by hardware when the word in the receive shift register is ready to be
transferred into the USART_TDATA register while the RBNE bit is set.
Cleared by writing 1 to OREC bit in USART_INTC register.
2
NERR
Noise error flag
0: No noise error is detected
1: Noise error is detected. In multibuffer communication, an interrupt will occur if the
ERRIE bit is set in USART_CTL2.
Set by hardware when noise error is detected on a received frame.
Cleared by writing 1 to NEC bit in USART_INTC register.
1
FERR
Frame error flag
0: No framing error is detected
1: Frame error flag or break character is detected. In multibuffer communication, an
interrupt will occur if the ERRIE bit is set in USART_CTL2.
Set by hardware when a de-synchronization, excessive noise or a break character
is detected. This bit will be set when the maximum number of transmit attempts is
reached without success (the card NACKs the data frame), when USART transmits
in smartcard mode.
Cleared by writing 1 to FEC bit in USART_INTC register.
0
PERR
Parity error flag
0: No parity error is detected
1: Parity error flag is detected. An interrupt will occur if the PERRIE bit is set in
USART_CTL0.
Set by hardware when a parity error occurs in receiver mode.
Cleared by writing 1 to PEC bit in USART_INTC register.
17.4.9. Interrupt status clear register (USART_INTC)
Address offset: 0x20
Reset value: 0x0000_0000
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This register has to be accessed by word (32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
WUC
Reserved
AMC
Reserved
w
w
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
EBC
RTC
Reserved
CTSC
LBDC
Reserved
TCC
Reserved
IDLEC
OREC
NEC
FEC
PEC
w
w
w
w
w
w
w
w
w
w
Bits
Fields
Descriptions
31:21
Reserved
Must be kept at reset value
20
WUC
Wakeup from Deep-sleep mode clear
Writing 1 to this bit clears the WUF bit in the USART_STAT register.
This bit is reserved in USART1.
19:18
Reserved
Must be kept at reset value
17
AMC
ADDR match clear
Writing 1 to this bit clears the AM bit in the USART_STAT register.
16:13
Reserved
Must be kept at reset value
12
EBC
End of timeout clear
Writing 1 to this bit clears the EB bit in the USART_STAT register.
This bit is reserved in USART1.
11
RTC
Receiver timeout clear
Writing 1 to this bit clears the RT flag in the USART_STAT register.
This bit is reserved in USART1.
10
Reserved
Must be kept at reset value
9
CTSC
CTS change clear
Writing 1 to this bit clears the CTSF bit in the USART_STAT register.
8
LBDC
LIN break detected clear
Writing 1 to this bit clears the LBDF flag in the USART_STAT register.
This bit is reserved in USART1.
7
Reserved
Must be kept at reset value
6
TCC
Transmission complete clear
Writing 1 to this bit clears the TC bit in the USART_STAT register.
5
Reserved
Must be kept at reset value
4
IDLEC
Idle line detected clear
Writing 1 to this bit clears the IDLEF bit in the USART_STAT register.
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3
OREC
Overrun error clear
Writing 1 to this bit clears the ORERR bit in the USART_STAT register.
2
NEC
Noise detected clear
Writing 1 to this bit clears the NERR bit in the USART_STAT register.
1
FEC
Frame error flagclear
Writing 1 to this bit clears the FERR bit in the USART_STAT register
0
PEC
Parity error clear
Writing 1 to this bit clears the PERR bit in the USART_STAT register.
17.4.10. Receive data register (USART_RDATA)
Offset: 0x24
Reset value: Undefined
This register has to be accessed by word (32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
RDATA[8:0]
r
Bits
Fields
Descriptions
31:9
Reserved
Must be kept at reset value
8:0
RDATA[8:0]
Receive Data value
The received data character is contained in these bits.
The value read in the MSB (bit 7 or bit 8 depending on the data length) will be the
received parity bit, if receiving with the parity is enabled (PERR bit set to 1 in the
USART_CTL0 register).
17.4.11. Transmit data register (USART_TDATA)
Offset: 0x28
Reset value: Undefined
This register has to be accessed by word (32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
TDATA[8:0]
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rw
Bits
Fields
Descriptions
31:9
Reserved
Must be kept at reset value
8:0
TDATA[8:0]
Transmit Data value
The transmit data character is contained in these bits.
The value written in the MSB (bit 7 or bit 8 depending on the data length) will be
replaced by the parity, when transmitting with the parity is enabled (PERR bit set to
1 in the USART_CTL0 register).
This register must be written only when TBE bit in USART_STAT reigister is set.
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18. Debug (DBG)
18.1. Introduction
The DBG module helps debugger to debug power saving mode, TIMER, I2C, RTC, WWDGT,
FWDGT and CAN. When corresponding bit set, provide clock when in power saving mode or
hold the state for TIMER, WWDGT, FWDGT, RTC, I2C or CAN. (The contents of CAN is only
for GD32F170xx and GD32F190xx devices)
18.2. Function description
18.2.1. Debug support for power saving mode
When STB_HOLD bit in DBG control register 0 (DBG_CTL0) set and entering the standby
mode, the clock of AHB bus and system clock are provided by CK_IRC8M, and the debugger
can debug in standby mode. When exitting the standby mode, a system reset generated.
When DSLP_HOLD bit in DBG control register 0 (DBG_CTL0) set and entering the Deep-
sleep mode, the clock of AHB bus and system clock are provided by CK_IRC8M, and the
debugger can debug in Deep-sleep mode.
When SLP_HOLD bit in DBG control register 0 (DBG_CTL0) set and entering the sleep mode,
the clock of AHB bus for CPU is not closed, and the debugger can debug in sleep mode.
18.2.2. Debug support for TIMER, I2C, RTC, WWDGT, FWDGT and CAN
When the core halted and the corresponding bit in DBG control register 0 (DBG_CTL0) or
DBG control register 1 (DBG_CTLR1) is set, the following behaved will be occurred
For TIMER, the timer counters stopped and hold for debug.
For I2C, SMBUS timeout hold for debug.
For WWDGT or FWDGT, the counter clock stopped for debug.
For RTC, the counter stopped for debug.
For CAN, the receive register stopped counting for debug.
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18.3. DBG registers
18.3.1. ID code register (DBG_ID)
Address: 0xE004 2000
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
ID_CODE[31:16]
r
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
ID_CODE[15:0]
r
Bits
Fields
Descriptions
31:0
ID_CODE[31:0]
DBG ID code register
These bits can be read by software, These bits are unchanged constant.
18.3.2. Control register 0(DBG_CTL0)
For GD32F130xx and GD32F150xx devices
Address offset: 0x04
Reset value: 0x0000 0000; power reset only
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
TIMER13_
HOLD
Reserved
TIMER5_
HOLD
Reserved
I2C2
HOLD
I2C1_
HOLD
rw
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
I2C0_
HOLD
Reserved
TIMER2_
HOLD
TIMER1_
HOLD
TIMER0_
HOLD
WWDGT_
HOLD
FWDGT_
HOLD
Reserved
STB_
HOLD
DSLP_HOLD
SLP_
HOLD
rw
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31:28
Reserved
Must be kept at reset value
27
TIMER13_HOLD
TIMER13 hold register
This bit is set and reset by software.
0: No effect
1: Hold the TIMER13 counter for debug when core halted
26:20
Reserved
Must be kept at reset value
19
TIMER5_HOLD
TIMER5 hold register
This bit is set and reset by software.
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0: No effect
1: Hold the TIMER5 counter for debug when core halted
18
Reserved
Must be kept at reset value
17
I2C2_HOLD
I2C2 hold register
This bit is set and reset by software.
0: No effect
1: Hold the I2C2 SMBUS timeout for debug when core halted
16
I2C1_HOLD
I2C1 hold register
This bit is set and reset by software.
0: No effect
1: Hold the I2C1 SMBUS timeout for debug when core halted
15
I2C0_HOLD
I2C0 hold register
This bit is set and reset by software.
0: No effect
1: Hold the I2C0 SMBUS timeout for debug when core halted
14:13
Reserved
Must be kept at reset value
12
TIMER2_HOLD
TIMER2 hold register
This bit is set and reset by software.
0: No effect
1: Hold the TIMER2 counter for debug when core halted
11
TIMER1_HOLD
TIMER1 hold register
This bit is set and reset by software.
0: No effect
1: Hold the TIMER1 counter for debug when core halted
10
TIMER0_HOLD
TIMER0 hold register
This bit is set and reset by software.
0: No effect
1: Hold the TIMER0 counter for debug when core halted
9
WWDGT_HOLD
WWDGT hold register
This bit is set and reset by software.
0: No effect
1: Hold the WWDGT counter clock for debug when core halted
8
FWDGT_HOLD
FWDGT hold register
This bit is set and reset by software.
0: No effect
1: Hold the FWDGT counter clock for debug when core halted
2
STB_HOLD
Standby mode hold register
This bit is set and reset by software.
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0: No effect
1: At the standby mode, the system clock and HCLK are provided by
CK_IRC8M, a system reset generated when exiting standby mode
1
DSLP_HOLD
Deep-sleep mode hold register
This bit is set and reset by software.
0: No effect
1: At the Deep-sleep mode, the system clock and HCLK are provided by
CK_IRC8M
0
SLP_HOLD
Sleep mode hold register
This bit is set and reset by software.
0: No effect
1: At the sleep mode, the HCLK is on
For GD32F170xx and GD32F190xx devices
Address offset: 0x04
Reset value: 0x0000 0000; power reset only
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
TIMER13_
HOLD
Reserved
CAN1_
HOLD
Reserved
TIMER5_
HOLD
Reserved
I2C2_
HOLD
I2C1
HOLD
rw
rw
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
I2C0_
HOLD
CAN0_
HOLD
Reserved
TIMER2_
HOLD
TIMER1_
HOLD
TIMER0_
HOLD
WWDGT_
HOLD
FWDGT_
HOLD
Reserved
STB_
HOLD
DSLP_
HOLD
SLP_
HOLD
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31:28
Reserved
Must be kept at reset value
27
TIMER13_HOLD
TIMER13 hold register
This bit is set and reset by software.
0: No effect
1: Hold the TIMER13 counter for debug when core halted
26:22
Reserved
Must be kept at reset value
21
CAN1_HOLD
CAN1 hold register
This bit is set and reset by software.
0: No effect
1: Hold the CAN1 for debug when core halted
20
Reserved
Must be kept at reset value
19
TIMER5_HOLD
TIMER5 hold register
This bit is set and reset by software.
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524
0: No effect
1: Hold the TIMER5 counter for debug when core halted
18
Reserved
Must be kept at reset value
17
I2C2_HOLD
I2C2 hold register
This bit is set and reset by software.
0: No effect
1: Hold the I2C2 SMBUS timeout for debug when core halted
16
I2C1_HOLD
I2C1 hold register
This bit is set and reset by software.
0: No effect
1: Hold the I2C1 SMBUS timeout for debug when core halted
15
I2C0_HOLD
I2C0 hold register
This bit is set and reset by software.
0: No effect
1: Hold the I2C0 SMBUS timeout for debug when core halted
14
CAN0_HOLD
CAN0 hold register
This bit is set and reset by software.
0: No effect
1: Hold the CAN0 for debug when core halted
13
Reserved
Must be kept at reset value
12
TIMER2_HOLD
TIMER2 hold register
This bit is set and reset by software.
0: No effect
1: Hold the TIMER2 counter for debug when core halted
11
TIMER1_HOLD
TIMER1 hold register
This bit is set and reset by software.
0: No effect
1: Hold the TIMER1 counter for debug when core halted
10
TIMER0_HOLD
TIMER0 hold register
This bit is set and reset by software.
0: No effect
1: Hold the TIMER0 counter for debug when core halted
9
WWDGT_HOLD
WWDGT hold register
This bit is set and reset by software.
0: No effect
1: Hold the WWDGT counter clock for debug when core halted
8
FWDGT_HOLD
FWDGT hold register
This bit is set and reset by software.
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525
0: No effect
1: Hold the FWDGT counter clock for debug when core halted
2
STB_HOLD
Standby mode hold register
This bit is set and reset by software.
0: No effect
1: At the standby mode, the system clock and HCLK are provided by
CK_IRC8M, a system reset generated when exit stanby mode
1
DSLP_HOLD
Deep-sleep mode hold register
This bit is set and reset by software.
0: No effect
1: At the Deep-sleep mode, the system clock and HCLK are provided by
CK_IRC8M
0
SLP_HOLD
Sleep mode hold register
This bit is set and reset by software.
0: No effect
1: At the sleep mode, the HCLK is on
18.3.3. Control register 1 (DBG_CTL1)
Address offset: 0x08
Reset value: 0x0000 0000; power reset only
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
TIMER16_
HOLD
TIMER15_
HOLD
TIMER14_
HOLD
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
RTC_
HOLD
Reserved
rw
Bits
Fields
Descriptions
31:19
Reserved
Must be kept at reset value
18
TIMER16_HOLD
TIMER16 hold register
This bit is set and reset by software.
0: No effect
1: Hold the TIMER16 counter for debug when core halted
17
TIMER15_HOLD
TIMER15 hold register
This bit is set and reset by software.
0: No effect
1: Hold the TIMER15 counter for debug when core halted
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16
TIMER14_HOLD
TIMER14 hold register
This bit is set and reset by software.
0: No effect
1: Hold the TIMER14 counter for debug when core halted
15:11
Reserved
Must be kept at reset value
10
RTC_HOLD
RTC hold register
This bit is set and reset by software.
0: No effect
1: Hold the RTC counter for debug when core halted
9:0
Reserved
Must be kept at reset value
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19. Universal serial bus full-speed device interface (USBD)
This chapter applies to GD32F150xx devices, mainly describes the USB full-speed device
controller and its interface. As this module is different from other serial ports, so the higher
complexity of it requires developers to know about its background knowledge. If developers
want to get its latest information, please refer to the official specification of USB 2.0 version
which is published by the USB Implements Forum (USB-IF).
19.1. Introduction
The Universal Serial Bus (USB) is a four-wire bus, which are the power line VBus, the data
line D+ (DP), the data line D- (DM) and the ground line GND. It supports communication
between a host and the function device implemented by the USB controller. The host
controller allocates the USB bandwidth to attached devices through a token-based protocol.
It communicates data with device in polling method. The USB bus supports hot plugging and
dynamic configuration of the devices. All interactive processes are initiated by the host.
Every transmission between the USB host and the device is accomplished by transaction.
Transactions can be classified into three types: Setup transaction, Data-IN transaction and
Data-out transaction. Transaction consists of three kinds of data packets: token packet, data
packet and optional handshake packet.
The USB device interface implements the communication between a full-speed USB 2.0 bus
and the APB1 bus. According to USB standard request, it can deal with all USB packets: such
as detecting token packets, handling data packet transfer and processing handshake packets.
The format of transaction is performed by the hardware, including CRC generation and
checking. According to the USB protocol, each device can have a maximum of 16 logical or
32 physical endpoints. The USB controller supports up to 8 bidirectional endpoints or 16
mono-directional endpoints.
Each USB endpoint has a corresponding buffer located in a dedicated 512 byte SRAM. The
data transfer between host PC and the system memory is based on the data buffer. The data
transceiver of endpoint in its own buffer must comply with the condition that the state of
endpoint is valid. For isochronous transfer which is need to be in stable rate, and bulk transfer
with high throughput, the USB controller provides special handling and implements a double
buffer algorithm, which allows the isochronous endpoint or bulk endpoint to transmit and
receive data continuously without waiting for the state of endpoint to become valid, since that
buffers of these endpoints are always available, one is handling data, meanwhile, MCU can
use the other one.
The USB module can be placed in low-power mode (SUSPEND mode) by writing in the
Control register (USBD_CTL) whenever required. At this time, all static power dissipation is
avoided and the USB clock can be slowed down or stopped. It will be resumed when detect
activity at the USB bus.
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19.2. Main features
USB 2.0 full-speed device controller
Support USB 2.0 Link Power Management (LPM)
Support up to 8 configurable endpoints
Support double-buffered bulk/isochronous endpoints
Each endpoint supports control, bulk, isochronous or interrupt transfer types(exclude
endpoint 0)
Support USB suspend/resume operations
A dedicated 512-byte SRAM used for data packet buffer
Integrated USB PHY
19.2.1. Implementation
Table 19-1 describes the USB implementation in GD32F150xx devices.
Table 19-1. GD32F150xx USB implementation
USB features
GD32F150xx USB
Number of endpoints
8 bidirectional / 16 mono-
directional endpoints
Size of dedicated data packet
buffer(SRAM)
512 bytes
Dedicated data packet buffer access
scheme
2×16bits / word
USB 2.0 Link Power
Management(LPM)support
YES
19.2.2. Clock
According to the USB standard definition, the USB full-speed module adopt fixed 48MHz clock.
For using the USB module, it is need to open the two clock, one is the USB controller clock,
its frequency must be configured to 48MHz, and the other one is the APB1 USB interface
clock, that is APB1 bus clock, its frequency can be above or below 48MHz.
Note: in order to meet the system requirements of packet buffer interface and USB data
transfer rate, the frequency of the APB1 bus clock must be greater than 24MHz, so as to
avoid data buffer overflow and underflow.
48MHz clock of USB controller can be generated by MCU internal or external crystal oscillator,
through PLL frequency multiplication:
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Regard two frequency division of 8MHz internal oscillator as the input of the PLL, then
12 frequencies doubling of the clock
Regard 8MHz external oscillator as the input of the PLL, firstly frequency doubling, then
adopt USB Frequency divider to divide frequency
When the USB clock is generated by external crystal, only four USB frequency division
coefficients are 1, 1.5, 2 and 2.5 (useless, MCU frequency cannot reach 120 MHz).Thus, for
obtaining 48MHz clock, PLL frequencies doubling can only be 48MHz, 72MHz and 96MHz.
Note: Regardless of internal or external crystal oscillator generate USB clock, the clock
accuracy must reach ±500ppm. If the accuracy of the USB clock cannot meet the condition,
data transfer may not conform to the requirements of the USB specification, and even it may
lead USB cannot work directly.
19.2.3. Pin description
The USB controller in device mode uses 3 pins, DP, DM and VBus. DP and DM are data pins,
which are mainly used to send and receive data and fixed on the controller. Before enabling
USB, these pins default to ordinary GPIO after reset, after enabling USB, they will become
USB pins. As bus power supply USB device, the VBus pin is mainly used to supply power for
the controller, while it is not used in that USB controller is self powered device.
The pins DP and DM don’t need configure because they are connected to the USB internal
transceiver automatically as soon as the USB is enabled.
The signal pinouts are shown in the table below:
Table 19-2. GD32F150xx USB signal pinouts
USB pinout
GPIO pin
GPIO configuration
USBDP
PA12
As soon as the USB is enabled, these pins are
connected to the USB internal transceiver
automatically.
USBDM
PA11
19.3. Function description
19.3.1. Basic functional block
Figure 19-1,shows the block diagram of the USB peripheral
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Figure 19-1. USB peripheral block diagram
USB PHY Analog
transceiver
Control registers
and logic
Interrupt registers
and logic
Suspend
Timer
EPnCSR
registers
APB interface
Arbiter Packet
buffer
memory
Register
mapper Interrupt
mapper
APB wrapper
IRQs to NVIC
APB busPCLK
USB clock
（48MHz）
PCLK
（>12MHz）
USB
connector DP DM
S.I.E
TX-RX Endpoint
selection
Control
Packet
buffer
interface
Controller block
The USB controller includes the following blocks:
Built-in analog transceiver (ATX): The USB ATX connects to the USB pins DP and DM
to send/receive the bi-directional signals of the USB bus.
Serial interface engine (SIE): The SIE implements integrated full-speed USB protocol
layer. In order to ensure the speed, it is implemented by hardware without software
intervention. SIE is in charge of data transfer between endpoint buffers and USB bus.
The module features include: decodes and encodes the serial data, corrects error, bit
stuffing and relief stuffing, isochronous pattern recognition, CRC verifying and generating,
PID verifying and generating, parallel and serial conversion, address recognition, and
evaluation and generation of handshake signals.
Timer: The timer generates a start-of-frame locked clock pulse and detects a global
suspend (from the host) when no activity has occurred on the USB bus for 3ms.
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Packet buffer interface: this module mainly manages data packet buffers for endpoints
transmission and reception. It could select proper buffer for endpoints to meet SIE
demand and locate them in the right memory addresses according to endpoint register
data. It progressive increase address with each byte exchanging until the end of data
packet, as well as to follow up on the number of exchanged bytes for preventing buffer
overrun.
Endpoint control and status registers: Each endpoint has an associated register
containing its controlling information and current status. For mono-directional/single-
buffer endpoints, a single endpoint register can be used to implement two distinct
endpoints. The number of registers is 8, allowing up to 16 mono-directional/single-buffer
or 7 double-buffer endpoints in any combination. For example, the USB peripheral can
be programmed to have two double buffer endpoints and 12 mono-directional/single-
buffer endpoints.
Control registers: These registers contain information about the status and controlling of
the whole USB device.
Interrupt flag registers: These registers contain the interrupt flag and records of the
events. They can be used to inquire an interrupt reason, the interrupt status or to clear a
pending interrupt.
APB1 interface block
The USB APB1 interface includes the following blocks:
Data Packet buffer: The block is dedicated 512 bytes SRAM. There is reserved memory
for each implemented USB endpoint. The size of total buffer depends on the number of
endpoints, the packet maximum length of endpoint and whether to support double
buffering. This module is used by the data packet buffer interface and the corresponding
data structure is created. Application can directly access the buffer. It is composed of
256 16-bits words. However, the access mode of MCU is 32-bits, so the actual
occupancy memory size is 1024 bytes.
Arbiter: Since the USB module is connected to the APB1 bus through the APB1 interface,
the APB1 bus has a conflict with the USB interface when they all have memory access
request. The arbiter is used to resolve the conflict. It will give the APB1 bus higher priority,
and always keep half of the memory bandwidth for USB complete transmission. Through
this time division multiplexing strategy, the virtual dual port SRAM is realized, which
allows the application to access memory at the same time of the USB transmission. At
the same time, it allows any length of multi byte APB1 transmission in the transmission
process.
Register Mapper: This module collects the various byte-wide and bit-wide registers of
the USB peripheral in a structured 16-bits wide word set addressed by the APB1.
APB1 Wrapper: This module provides an interface to the APB1 for the memory and
register. It also maps the whole USB peripheral in the APB1 address space.
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Interrupt Mapper: This module is used to select interrupts which are generated by the
possible USB events and map them to different lines of the NVIC.
19.3.2. Buffer
USB buffer transfers data between MCU core and SIE. It is implemented by a special virtual
dual port SRAM memory, and it is mapped to the APB1 peripheral memory, from 0x4000 6000
to 0x4000 6400. The total capacity is 1KB, but USB uses actually only 512 bytes
Buffer descriptor table
Each USB endpoint has a relevant buffer descriptor only for control endpoint buffer. In
application, it is generally treated as a special function “register”. Since these registers are
not hardware mapped, their addresses are not constant. Register mainly control endpoints
related memory address, buffer size, and number of transfer bytes. If the endpoint which
corresponds to buffer descriptor is not enabled, the register of endpoint cannot come into use,
and then buffer descriptor turn into available SRAM. A set of these registers is known as the
buffer descriptor table, which provides a flexible method for the user to construct and control
various length and configuration endpoint buffer.
The buffer descriptor table is composed of many data structures that define the buffer address
and the length of the buffer. The first table item is defined by USBD_BADDR. An effective
endpoint usually has two packet buffers, which are used to send and receive, so it correspond
two table items. Each table item includes four 16-bits words, and thus is aligned with the 8
byte boundary.
Double buffer
In general, each endpoint has only one send buffer and one receive buffer, thus, for both
sending and receiving, USB endpoint adopt signal buffer. However, to meet the following two
kinds of USB transfer, the USB module implements a double buffer data transfer mode:
Bulk transfer: require high data throughput, ensure can achieve the fastest rate when the
bus is in idle state.
Isochronous transfer: which is real-time streaming transfer, require data must be at a
constant rate transfer, or arrive within a specific time limit.
As an endpoint register can be used to send and receive data, so endpoint register actually
control two buffers. For implementing double buffer, it is necessary to change two buffers
which are controlled by endpoint register into two send buffers or receive buffers. Actually, the
course of change from one buffer to double buffer is complex, referring to the “double buffer
endpoint” section for details.
Figure 19-2 describes the relationship between the buffer description table and the packet
buffer, including endpoint 0 which using single buffer and endpoint 1 which using double buffer.
Note: this figure is not drawn on the actual scale, and it is addressed through the USB bus
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16-bits mode.
Figure 19-2. An example with buffer descriptor table usage (USBD_BADDR = 0)
TXAR0
TXCNTR0
RXAR0
RXCNTR0
AR0
CNTR0
AR1
CNTR1
Endpoint 0
Transmission buffer
Endpoint 0
Reception buffer
IN Endpoint 1
Double buffer 1
IN Endpoint 1
Double buffer 0
0x00
0x02
0x0C
0xFF
0x0E
0x0A
0x08
0x06
0x04
19.3.3. Endpoint
The USB module supports dynamic configuration of the endpoint, except for the endpoint 0
(which is only configured to be control transfer mode), each endpoint could be configured to
be any one of four kinds of USB transfer mode. Except that endpoint 0 is only configured with
single buffer, other endpoints could be configured with single buffer or double buffer.
Single buffer endpoint
In general, if endpoint is configured with single buffer, there is only one buffer in each transfer
direction. Once the transaction is completed, the endpoint state will be automatically set to
the NAK state by hardware. At this time, the USB device needs to handle the previous data
transfer, however, if this USB endpoint meanwhile receives a new packet, USB device will
reply host with NAK packet. It leads host to retransmit the same data constantly until the
device could handle new data, and then to respond the ACK packet. Such a heavy
retransmission takes up lots of bandwidth, which affects the transmission rate in terms of the
bulk transfer, which need high throughput, and isochronous transfer, which require higher
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real-time performance. Therefore, the dual buffer is needed.
Double buffer endpoint
Double buffer endpoint use two buffers to send and receive data, one of them is used by
hardware, and the other one is used by application. In the course of using double buffer, USB
peripherals need to know which buffer is used by applications for avoiding conflict. Since there
are 2 data rollover bits in the USBD_EPxCS register, the USB device uses only 1 bit to handle
hardware data processing (double buffer function constraint one direction transfer),so
application program use the other bit to indicate which buffer is used at this time, that is what
is called ”SW_BUF”.
In the following table, the correspondence between USBD_EPxCS register bits and
DTOG/SW_BUF definition is explained.
Table 19-3. Double-buffering buffer flag definition
Buffer flag
Tx endpoint
Rx endpoint
DTOG
TX_DTG(USBD_EPxCS bit 6)
RX_DTG(USBD_EPxCS bit 14)
SW_BUF
USBD_EPxCS bit 14
USBD_EPxCS bit 6
The DTOG bit and the SW_BUF bit are responsible for the stream control. When a transfer
completes, the USB peripheral toggle the DTOG bit; when the data have been copied, the
application software need to toggle the SW_BUF bit. Except the first time, if the value of
DTOG bit equal to the SW_BUF’s, the transfer will pause, and NAK will be sent to host. When
the two bits do not equal, the transfer resume.
To enable the double-buffered feature, EP_CTL and EP_KCTL need to be configured:
Setting EP_CTL = ’00
Setting EP_KCTL = ’1
Table 19-4. Double buffer usage
Endpoint
Type
DTOG
SW_
BUF
Packet buffer used by the
USB peripheral
Packet buffer used by the
application software
OUT
0
1
RXARn_0 / RXCNTRn_0 buffer
description table locations.
RXARn_1 / RXCNTRn_1 buffer
description table locations.
1
0
RXARn_1 / RXCNTRn_1 buffer
description table locations.
RXARn_0 / RXCNTRn_0 buffer
description table locations.
IN
0
1
TXARn_0 / TXCNTn_0 buffer
description table locations.
TXARn_1 / TXCNTn_1 buffer
description table locations.
1
0
TXARn_1 / TXCNTn_1 buffer
description table locations.
TXARn_0 / TXCNTn_0 buffer
description table locations.
Endpoint initialization
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The USB endpoints must be initialized before they are used, initialization process is as follows:
Initialize the TADDRx/RADDRx registers with transmission/reception data buffer address;
Configure The EP_CTL and EP_KCTL bits in the USBD_EPxCS register according to
the endpoint usage;
For transmission, initiate the TXCNTn and enable TX_STA ; for reception, initiate the
RXCNTRn, BLKSIZ and BLKNUM, then enable RX_STA.
For isochronous and double-buffered bulk endpoints, both transmission and reception
relevant fields are need to be initialized. Once the endpoint is enabled, register USBD_EPxCS,
buffer address and COUNT filed should not be modified by the application software.
Endpoint request
If there are multiple endpoints trigger interrupt request at the same time, the hardware will
respond to the highest priority endpoint. The priority definition method for endpoint is as
follows:
Firstly, depending on the basis of the endpoint attributes, synchronous endpoint and
double buffering endpoint has a high priority, the other endpoints are low priority
Then, according to the same attribute endpoint’s endpoint number to arrange, the smaller
the endpoint number, the higher the priority
Application should conform to the above priority policy order for processing endpoint interrupt
request.
19.3.4. Interrupt handling
There are two kinds of USB interrupt event: device interrupt and endpoint interrupt. Device
interrupt event includes the reset, suspend, wakeup and so on. Endpoint interrupt event only
includes successful transfer interrupt. All interrupt events are captured through interrupt flag
register, When there is an interrupt condition occur, the corresponding interrupt status bit will
be set by the hardware (regardless of whether the interrupt enable bit is set). The software
can program the corresponding bits of interrupt enable register, thereby NVIC triggers the
USB interrupt event. NVIC can configure three kinds of USB interrupt as following:
USB low-priority interrupt: triggered by all USB events
USB high-priority interrupt: triggered only by a successful transfer event for isochronous
and double buffer bulk transfer
USB wakeup interrupt: triggered by the wakeup events.
USB low-priority interrupts handling
Checking interrupt flag bits in the interrupt service program is to confirm the specific interrupt
event. After the corresponding operation implemented, interrupt flag bit must be cleared,
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otherwise the same interrupt is triggered again. Even if the multiple interrupt flags are set,
only one interrupt will be triggered. The sequence to check each interrupt flag of the interrupt
flag register in the interrupt service program, which determines the priority of each interrupt
event, processing procedures in accordance with this priority to handle the interrupt event.
USB high-priority interrupts handling
It is only for handling isochronous transfer and dual buffering bulk transfer. Surely, the two
transfers can also be configured as lower priority interrupt, but if it is configured as high priority
interrupt, they will be handled in high priority interrupt process instead of lower priority process.
Since there is only normally successful transfer interrupt in the interrupt service program, its
handling speed is faster than lower priority interrupt.
USB wakeup interrupt handling
In general MCU sleep is awaked by external interrupt event. However, USB is awaked by
both external interrupt event and internal interrupt event. The external interrupt source is used
to wake up the USB by triggering the interrupt line 18. The internal wake event is mainly
aroused by the signal. Specific wake-up interrupt handling process is directly performed
through the USB low priority interrupt processing service program.
The USB clock will be restored and the interrupt flag bit will be cleared in the wake up interrupt
service program.
19.3.5. Reset events
System reset and power on reset
Upon the system or the power reset, the USB controller and the interface are in the closed
state. At this time, all the endpoints are in a disabled state, the USB module will not respond
to any group. Applications need to be carried out as follows:
Firstly, the USB controller is configured to 48MHz, and the APB1 interface clock is turned on,
so as to activate the register unit clock and then clear the reset signal;
Secondly, open the analog part of the USB transceiver, which opens the internal voltage
required for a period of time;
Finally, the configuration of the register and buffer description table is required, so that the
USB module can carry out normal interrupt processing and data transfer.
The USB firmware should do as follows:
Reset CLOSE bit in USBD_CTL register
Wait for the internal reference voltage stability
Clear SETRST bit in USBD_CTL register
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Clear the IFR register to remove the redundant pending interrupt and then enable other
unit
Reset interrupt
Once reset occurs, the USB module will reset the internal protocol state machine, and the
sending and receiving parts will be banned until the reset interrupt bit is cleared. All the
configuration registers will keep the original state and will not be reset to ensure that correct
execution can transfer immediately after reset, however, device address and endpoint register
will be reset.
The USB firmware should do as follows:
Set USBEN bit in USBD_DADDR register to enable USB module in 10ms
Initialize the EP0CS register and its related packet buffers
19.3.6. Transfer procedure
USB transaction summary
USB module transfers data between the device endpoint and the host through the transaction.
Host defines the direction of the transaction: IN and OUT are relative to the host, the IN
transaction is to transfer data from the device to the host, the OUT transaction is to transfer
data from the host to the device. All the transactions are initiated by the host controller.
The process of a transaction is generally as follows: when the host sends a valid function /
endpoint token packet that can be recognized by the USB module, the USB device is properly
received and needs to send or receive data, which will be followed by the associated data
transfer process. The USB module is used to realize the data exchange between the special
buffer and the port through the buffer description block and the endpoint register, and then
realizes the data exchange with the host through the port. After all the data transfer is
completed, if required, according to the direction of transmission, send or receive the
corresponding handshake packet.
After each successful transaction, it will trigger an interrupt related to the endpoint. In the case
of enabling interrupt related to the endpoint, the Interrupt flag register can be read to handle
the corresponding interrupt event.
Figure 19-3 describes the relationship between the USB transaction and the interrupt event:
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Figure 19-3 .USB transaction and the interrupt event
SOF
Differential
data SETUP DATA STATUS SOF
Control
transfer
1ms frame
SOF interrupt
SOFIF
Reset
Reset interrupt
RSTIF
SETUP token data ACK
From host From host To host
IN token data ACK
From host To host From host
OUT token no data ACK
From host From host To host
Transaction
Set STIF
Set STIF
Set STIF
Transaction
finished
Data transmission (IN transaction)
When a valid endpoint receives an IN token packet, the SIE will begin to read TXCNTn bytes
of parallel data from the endpoint associated TADDRx buffer. After the IN packet transmission,
the data will be loaded into the output shift register and converted to serial data to be sent
through the USB ATX to the USB bus and send to host. At the end of the data transmission,
the hardware will send the computed CRC to the host. If the endpoint indicated by the IN
group is invalid, a NAK or STALL handshake is sent according to the TX_STA value. The USB
peripheral transmit the data packet from the address indicated by TADDRx by LSB order.
When receiving the ACK sent from the host, then the USB peripheral will toggle the TX_DTG,
set TX_STA=’10 (NAK) and TX_ST bit. The application software can identify which endpoint
has completed transfer by checking the EPNUM and DIR bits in the USBD_INTF register.
After filled the data packet memory with data, the application software can start next transfer
by re-enable the endpoint by setting TX_STA=’11 (VALID).
Data reception (OUT and SETUP transaction)
When a valid endpoint receives an OUT or SETUP token packet, the USB ATX will receive
the bidirectional data on the USB bus. SIE receives serial data from the ATX and converts
them into parallel data streams. These data streams are stored in the buffer by the RADDRx
controlled. And the controller updates RXCNTRn with actually received number of bytes. The
values of BLKSIZ and BLKNUM are used to compute the BUF_COUNT, which is used to
detect the buffer overrun. The USB peripheral receives the data from the host by LSB order
and the computed CRC. When detecting the end of DATA packet, the computed CRC and
received CRC are compared. If no errors occur, an ACK handshake packet is sent to the host.
If any error happens during reception, the USB peripheral set the ERRIF bit and still copy
data into the packet memory buffer, but not send the ACK packet. The USB peripheral itself
can recover from reception errors and continue to handle next transfer. The USB peripheral
never access outside the packet memory buffer, which is defined by BLKSIZ and BLKNUM.
The received 2-byte CRC which follow data bytes is also copied to the packet memory buffer.
If the length of data is greater than actually allocated length, the excess data are not copied.
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This is a buffer overrun condition. A STALL handshake is sent, and this transaction fails.
If an addressed endpoint is invalid, a NAK or STALL handshake packet is sent instead of the
ACK according to bits RX_STA in the USBD_EPxCS register, no data is written in the
reception memory buffers. Reception memory buffers are written starting from the address
contained in the RADDRx, the number of bytes corresponding to the received data packet
length, CRC included (i.e. data payload length + 2), or up to the last allocated memory location,
as defined by BLKSIZ and BLKNUM. In this way, the USB peripheral never writes beyond the
end of the allocated reception memory buffer area. If the length of the data packet payload
(actual number of bytes used by the application) is greater than the allocated buffer, the USB
peripheral detects a buffer overrun condition. In this case, a STALL handshake is sent instead
of the usual ACK to notify the problem to the host, no interrupt is generated and the
transaction is considered failed.
If no error happens, the USB peripheral send the ACK handshake packet to the host, toggle
RX_DTG bit, set RX_STA=‘10 (NAK) and RX_ST bit. The application software checks the
EPNUM and DIR bits in the USBD_INTF register to determine which endpoint to trigger the
RX_ST. After handling the received data, the application software can initiate another
transaction by setting RX_STA=’11 (Valid).
Control transfers
Control transfers require that a SETUP transaction be started from the host to a device to
describe the type of control access that the device should perform. The SETUP transaction
is followed by zero or more control DATA transactions that carry the specific information for
the requested access. Finally, a STATUS transaction completes the control transfer and
allows the endpoint to return the status of the control transfer to the client software. After the
STATUS transaction for a control transfer is completed, the host can urge the next control
transfer for the endpoint.
To initialize the control transfer, TX_DTG and RX_DTG bits are set to 1 and 0 respectively,
and both TX_STA and RX_STA are set to ‘10 (NAK). According to the SETUP contents, the
application software can determine if the next transactions are IN or OUT. When RX_ST event
happens during control transfer, the SETUP bit must be firstly checked. If it is 1, it means a
SETUP transaction, or else a normal OUT one. The USB peripheral is aware of the number
and direction of data transfer by analyzing the contents of SETUP transaction, and is required
to set the unused direction to STALL except the last data stage.
At the last data stage, the application software set the control endpoint opposite direction to
NAK. This will keep the host waiting for the completion of the control operation. If the operation
completes successfully, the software will change NAK to VALID, otherwise to STALL. If the
status stage is an OUT transaction, the STATUS_OUT bit should be set, so that a status
transaction with non-zero data will be answered STALL to indicate an error happen.
The USB specification requires that the SETUP packet of the host has an automatic retransfer
function, which means that the device cannot respond to the SETUP request of the host with
a non ACK packet (NAK packet or STALL packet). When the SETUP packet transmission
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fails, the next SETUP packet transmission will be triggered.
The RX_STA bit of the control endpoint cannot be set to '00 (disabled) state. When the SETUP
token is received, the USB receives the data, performs the requested data transmission and
sends back an ACK handshake packet. If that endpoint has a previously issued RX_ST
request not yet handled by the application, the USB will discard the SETUP transaction and
does not answer with any handshake packet regardless of its state, simulating a reception
error and forcing the host to send the SETUP token again. It is to avoid missing another
SETUP packet transfer which following RX_ST interrupt.
Isochronous transfers
Isochronous transfers can guarantee constant data rate and bounded latency, but do not
support data retransmission in response to errors on the bus. A receiver can check that a
transmission error occurred. The bottom USB protocol does not allow handshakes to be
returned to the transmitter of an isochronous pipe. Normally, handshakes would be returned
to tell the transmitter whether a packet was successfully received or not. Consequently, the
isochronous transaction does not have a handshake phase, and have no ACK packet after
the data packet. Data toggling is not supported, and only DATA0 PID is used to start a data
packet.
The endpoint is defined as isochronous endpoint by setting the EP_CTL bits to ‘10. The STA
bits have two possible values: ‘00 (Disabled) and ‘11 (Valid), any other value is illegal. The
application software can implement double-buffering to improve performance. By swapping
transmission and reception data packet buffer on each transaction, the application software
can copy the data into or out of a buffer, at the same time the USB peripheral handle the data
transmission or reception of data in another buffer. The DTOG bit indicates that the USB
peripheral is currently using which buffer.
The application software initializes the DTOG according to the first buffer to be used. At the
end of each transaction, the RX_ST or TX_ST bit is set depending on the enabled direction,
regardless of CRC errors and buffer-overrun condition (if errors happen, the ERRIF bit will be
set). At the same time, The USB peripheral will toggle the DTOG bit, but not affect the STA
bits.
19.3.7. Power management
Power mode
USB applications tend to have several different power requirements and configurations. The
most common mode of power supply is as follows:
1. Bus power supply mode: the USB protocol insists on power management by the USB
device which requires the device to draw power from the bus. The following constraints
should be met by the bus-powered device.
A device in the non-configured state should draw a maximum of 100mA from the USB
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bus.
A configured device can draw only up to what is specified in the Max Power field of
the configuration descriptor. The maximum value is 500mA.
A suspended device should draw a maximum of 500uA.
2. Self powered mode: in this mode, USB is applied to provide power for itself, only a very
small part of the power supply comes from USB
3. Dual power with self-power dominance mode: some applications may require a dual
power option. This allows the application to use internal power primarily, but switch to
power from the USB when no internal power is available.
The USB module supports both the bus power supply and the self powered mode, and the
switching which requires manual control between the two modes.
Suspend and wakeup
A device will go into the SUSPEND state if there is no activity on the USB bus for more than
3ms. As the full speed mode of the USB host sends a start frame packet (SOF) every
millisecond, the suspend mode can be determined by detecting 3 consecutive SOF packet
loss events. A suspended device wakes up, if RESUME signaling is detected. RESUME
signaling is derived from the RESUME sequence, which can be initiated by the host, and can
also be triggered by the device itself. Under the SUSPEND state, the hardware do not detect
the suspend signal until wakeup process complete.
The USB peripheral also supports software initiated remote wakeup. Remote wakeup always
means device to wakeup host. At this time, it requires to wakeup USB module first, then
wakeup host. To initiate remote wakeup, the application software must enable all clocks and
clear the suspend bit. This will cause the hardware to generate a remote wakeup signal
upstream.
Setting the SETSPS bit to 1 enables the SUSPEND mode, and it will disable the check of
SOF reception. Setting the LOWM bit to 1 will shut down the static power consumption in the
analog USB transceivers, but the resume signal is still able to be detected.
Setting the RSREQ bit to 1 and clearing it in 10ms will initiate the RESUME sequence. (The
time interval of 10ms can be implemented with ESOF interrupt, the interrupt occurs once per
1ms in the kernel.)
Link Power Management (LPM) Level L1
A device will go into the LPM L1 state (sleep state) if the host sends the EXT PID and LPM
SubPID when the SUB_STA bits in USB sub endpoint registers is 0x3(Valid).
Setting the SETSPS bit to 1 enables the power saving mode, and it will disable the check of
SOF reception. Setting the LOWM bit to 1 will shut down the static power consumption in the
analog USB transceivers, but the resume signal is still able to be detected. When the resume
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signal is detected, sleep state will exit.
19.4. USB registers
19.4.1. Control register (USBD_CTL)
Address offset: 0x40
Reset value: 0x0003
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
STIE
PMOUIE
ERRIE
WKUPIE
SPSIE
RSTIE
SOFIE
ESOFIE
Reserved
RSREQ
SETSPS
LOWM
CLOSE
SETRST
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rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
15
STIE
Successful transfer interrupt enable
0: Successful transfer interrupt disabled
1: Interrupt generated when STIF bit in USBD_INTF register is set
14
PMOUIE
Packet memory overrun / underrun interrupt enable
0: No interrupt generated when packet memory overrun / underrun
1: Interrupt generated when PMOUIF bit in USBD_INTF register is set
13
ERRIE
Error interrupt enable
0: Error interrupt disabled
1: Interrupt generated when ERRIF bit in USBD_INTF register is set
12
WKUPIE
Wakeup interrupt enable
0: Wakeup interrupt disabled
1: Interrupt generated when WKUPIF bit in USBD_INTF register is set
11
SPSIE
Suspend state interrupt enable
0: Suspend state interrupt disabled
1: Interrupt generated when SPSIF bit in USBD_INTF register is set
10
RSTIE
USB reset interrupt enable
0: USB reset interrupt disabled
1: Interrupt generated when RSTIF bit in USBD_INTF register is set
9
SOFIE
Start of frame interrupt enable
0: Start of frame interrupt disabled
1: Interrupt generated when SOFIF bit in USBD_INTF register is set.
8
ESOFIE
Expected start of frame interrupt enable register
0: Expected start of frame interrupt disabled
1: Interrupt generated when ESOFIF bit in USBD_INTF register is set
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7:5
Reserved
Must be kept at reset value
4
RSREQ
The software set a resume request to the USB host, and the USB host should drive
the resume sequence according the USB specifications
0: No resume request
1: Send resume request.
3
SETSPS
The software should set suspend state when SPSIF bit in USBD_INTF register is set
0: Not set suspend state.
1: Set suspend state.
2
LOWM
When set this bit, the USB goes to low-power mode at suspend state. If resume from
suspend state, the hardware reset this bit
0: No effect
1: Go to low-power mode at suspend state
1
CLOSE
When this bit set, the USB goes to close state, and completely close the USB and
disconnected from the host
0: Not in close state
1: In close state.
0
SETRST
When this bit set, the USB peripheral should be reset
0: No reset
1: A reset generated
19.4.2. Interrupt flag register (USBD_INTF)
Address offset: 0x44
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
STIF
PMOUIF
ERRIF
WKUPIF
SPSIF
RSTIF
SOFIF
ESOFIF
Reserved
DIR
EPNUM[3:0]
r
rc_w0
rc_w0
rc_w0
rc_w0
rc_w0
rc_w0
rc_w0
r
r
Bits
Fields
Descriptions
15
STIF
Successful transfer interrupt flag
This bit set by hardware when a successful transaction completes
14
PMOUIF
Packet memory overrun / underrun interrupt flag
This bit set by hardware to indicate that the packet memory is inadequate to hold
transfer data. The software writes 0 to clear this bit.
13
ERRIF
Error interrupt flag
This bit set by hardware when an error happens during transaction. The software
writes 0 to clear this bit.
12
WKUPIF
Wakeup interrupt flag
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This bit set by hardware in the SUSPEND state to indicate that activity is detected.
The software writes 0 to clear this bit.
11
SPSIF
Suspend state interrupt flag
When no traffic happen in 3 ms, hardware set this bit to indicate a SUSPEND request.
The software writes 0 to clear this bit.
10
RSTIF
USB reset interrupt flag
Set by hardware when the USB RESET signal is detected. The software writes 0 to
clear this bit.
9
SOFIF
Start of frame interrupt flag
Set by hardware when a new SOF packet arrives, The software writes 0 to clear this
bit.
8
ESOFIF
Expected start of frame interrupt flag
Set by the hardware to indicate that a SOF packet is expected but not received. The
software writes 0 to clear this bit.
7:5
Reserved
Must be kept at reset value
4
DIR
Direction of transaction
Set by the hardware to indicate the direction of the transaction
0: IN type
1: OUT type
3:0
EPNUM[3:0]
Endpoint Number
Set by the hardware to identify the endpoint which the transaction is directed to
19.4.3. Status register (USBD_STAT)
Address offset: 0x48
Reset value: 0x0XXX where X is undefined
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RX_DP
RX_DM
LOCK
SOFLN[1:0]
FCNT[10:0]
r
r
r
r
r
Bits
Fields
Descriptions
15
RX_DP
Receive data + line status
Represent the status on the DP line.
14
RX_DM
Receive data - line status
Represent the status on the DM line.
13
LOCK
Locked the USB
Set by the hardware indicate that at the least two consecutive SOF have been
received.
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12:11
SOFLN[1:0]
SOF lost number
Increment every ESOFIF happens by hardware.
Cleared once the reception of SOF.
10:0
FCNT[10:0]
Frame number counter
The Frame number counter incremented every SOF received.
19.4.4. Device address register (USBD_DADDR)
Address offset: 0x4C
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
USBEN
USBADDR[6:0]
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Bits
Fields
Descriptions
15:8
Reserved
Must be kept at reset value
7
USBEN
USB device enable
Set by software to enable the USB device.
0: The USB device disabled. No transactions handled.
1: The USB device enabled.
6:0
USBADDR[6:0]
USB device address
After bus reset, the address is reset to
0x00. If the enable bit is set, the device will respond on packets
for function address DEV_ADDR.
19.4.5. Buffer address register (USBD_BADDR)
Address offset: 0x50
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
BAR[15:3]
Reserved
rw
Bits
Fields
Descriptions
15:3
BAR[15:3]
Buffer address
Start address of the allocation buffer(512byte on-chip SRAM), used for buffer
descriptor table, packet memory.
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2:0
Reserved
Must be kept at reset value
19.4.6. Endpoint n control/status register (USBD_EPxCS), n=[0..7]
Address offset: 0x00 to 0x1C
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RX_ST
RX_DTG
RX_STA[1:0]
SETUP
EP_CTL[1:0]
EP_KCTL
TX_ST
TX_DTG
TX_STA[1:0]
EP_AR[3:0]
rc_w0
t
t
r
rw
rw
rc_w0
t
t
rw
Bits
Fields
Descriptions
15
RX_ST
Reception Successful Transferred
Set by hardware when a successful OUT/SETUP transaction complete.
Cleared by software by writing 0.
14
RX_DTG
Reception Data PID Toggle
This bit represent the toggle data bit (0=DATA0,1=DATA1)for non-isochronous
endpoint.
Used to implement the flow control for double-buffered endpoint.
Used to swap buffer for isochronous endpoint.
13:12
RX_STA[1:0]
Reception status bits
Toggle by writing 1 by software.
Remain unchanged by writing 0.
Refer to the table below
11
SETUP
Setup transaction completed
Set by hardware when a SETUP transaction completed.
10:9
EP_CTL[1:0]
Endpoint type control
Refer to the table below
8
EP_KCTL
Endpoint kind control
The exact meaning depends on the endpoint type.
Refer to the table below
7
TX_ST
Transmission Successful Transfer
Set by hardware when a successful IN transaction complete.
Clear by software.
6
TX_DTG
Transmission Data PID Toggle
This bit represent the toggle data bit (0=DATA0,1=DATA1)for non-isochronous
endpoint.
Used to implement the flow control for double-buffered endpoint.
Used to swap buffer for isochronous endpoint.
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5:4
TX_STA[1:0]
Status bits, for transmission transfers
Refer to the table below
3:0
EP_AR
Endpoint address
Used to direct the transaction to the target endpoint.
Table 19-5. Reception status encoding
RX_STA[1:0]
Meaning
00
DISABLED: ignore all reception requests of this endpoint
01
STALL: STALL handshake status
10
NAK: NAK handshake status
11
VALID: enable endpoint for reception.
Table 19-6. Endpoint type encoding
EP_CTL[1:0]
Meaning
00
BULK
01
CONTROL
10
ISO
11
INTERRUPT
Table 19-7. Endpoint kind meaning
EP_CTL[1:0]
EP_KCTL Meaning
00
BULK
DBL_BUF
01
CONTROL
STATUS_OUT
Table 19-8. Transmission status encoding
TX_STA[1:0]
Meaning
00
DISABLED: ignore all transmission requests of this endpoint
01
STALL: STALL handshake status
10
NAK: NAK handshake status
11
VALID: enable this endpoint for transmission.
19.4.7. Transmission buffer address register x (USBD_TADDRx)
Address offset: [USBD_BADDR] + n*16
USB local address: [USBD_BADDR] + n*8
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
TXARn[15:1]
TXARn0
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Bits
Fields
Descriptions
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15:1
TXARn[15:1]
Transmission buffer address
Start address of the packet buffer containing data to be sent when receive next IN
token.
0
TXARn[0]
Must be set to 0
19.4.8. Transmission byte count register x (USBD_TCNTx)
Address offset: [USBD_BADDR] + n*16 + 4
USB local Address: [USBD_BADDR] + n*8 + 2
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
TXCNTn[9:0]
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Bits
Fields
Descriptions
15:10
Reserved
Must be kept at reset value
9:0
TXCNTn[9:0]
Transmission bytes count
The number of bytes to be transmitted at next IN token
19.4.9. Reception buffer address register x (USBD_RADDRx)
Address offset: [USBD_BADDR] + n*16 + 8
USB local Address: [USBD_BADDR] + n*8 + 4
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RXARn[15:1]
RXARn0
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Bits
Fields
Descriptions
15:1
RXARn[15:1]
Reception buffer address
Start address of packet buffer containing the data
received by the endpoint at the next OUT/SETUP token.
0
RXARn[0]
Must be set to 0
19.4.10. Reception byte count register x (USBD_RCNTx)
Address offset: [USBD_BADDR] + n*16 + 12
USB local Address: [USBD_BADDR] + n*8 + 6
This register can be accessed by half-word(16-bit) or word(32-bit)
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15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
BLKSIZ
BLKNUM[4:0]
RXCNTRn[9:0]
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rw
r
Bits
Fields
Descriptions
15
BLKSIZ
Block size
0: Block size is 2 bytes
1: Block size is 32 bytes
14:10
BLKNUM[4:0]
Block number
The number of blocks allocated to the packet buffer.
9:0
RXCNTRn[9:0]
Reception bytes count
The number of bytes to be received at next OUT/SETUP token.
19.4.11. Sub-endpoint x registers (USBD_SEPx), n=[0..7]
Address offset: 0x100 to 0x11C
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
SUB_ST
Reserved
SUB_STA[1:0]
Reserved
SUBPID_ATTR
rc_w0
t
r
Bits
Fields
Descriptions
15
SUB_ST
Successful Receive for LPM Token
Set by hardware when a successful receiving for LPM token completely.
Cleared by software by writing 0.
14
Reserved
Must be kept at reset value
13:12
SUB_STA[1:0]
Status bits, for the handshake of receiving subpid LPM
Toggle by writing 1 by software.
Remain unchanged by writing 0.
Refer to the table below
11
Reserved
Must be kept at reset value
10:0
SUBPID_ATTR
LPM Token bmAttribute Field.
These bits write by hardware and read by software.
Table 19-9. Sub-endpoints status
SUB_STA[1:0]
Meaning
00
DISABLED: ignore all LPM token reception requests of this endpoint
01
STALL: STALL handshake status
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10
NYET: NYET handshake status
11
VALID: enable endpoint for reception LPM token
19.4.12. LPM control register (USBD_LPMCTL)
Address offset: 0x140
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
LPMSTIE
Reserved
rw
Bits
Fields
Descriptions
15
LPMSTIE
LPM token successful transfer interrupt enable
This bit set and reset by software
0: No interrupt generated
1: Interrupt generated when LPM token successful transferred
14:0
Reserved
Must be kept at reset value
19.4.13. LPM interrupt flag register (USBD_LPMINTF)
Address offset: 0x144
Reset value: 0x0000
This register can be accessed by half-word(16-bit) or word(32-bit)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
LPMSTIF
Reserved
rw
Bits
Fields
Descriptions
15
LPMSTIF
LPM token Correct transfer interrupt flag
This bit set and reset by software
0: No effect
1: LPM token Correct transferred
14:0
Reserved
Must be kept at reset value
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20. Real-time clock(RTC)
20.1. Introduction
The RTC provides a time which includes hour/minute/second/sub-second and a calendar
includes year/month/day/week day. The time and calendar are expressed in BCD code except
sub-second. Sub-second is expressed in binary code. Hour adjust for daylight saving time.
Works in power saving mode and smart wakeup for software configurable. Support extern
accurate low frequency clock for higher calendar accuracy.
20.2. Main features
Daylight saving compensation support by software
External high accurate low frequency(50Hz or 60Hz) clock for higher calendar accuracy
performed by reference clock detection option function
Atomic clock adjust(max adjust accuracy is 0.95ppm) for calendar calibration performed
by digital calibration function
Sub-second adjustment by shift function
Time-stamp function for saving event time
2 Tamper source can be choice and tamper type is configurable
Programmable calendar and field maskable alarm
Maskable interrupt source:
- Alarm
- Time-stamp detection
- Tamper detection
Five 32-bit universal backup registers which can keep data under power saving mode.
Backup register will be reset if tamper event detected
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20.3. Function description
20.3.1. Block diagram
Figure 20-1.Block diagram of RTC
Digital Smooth
Calibration
7-bit
Asynchronous
Prescaler
(Default = 128)
15-bit
Synchronous
Prescaler
(Default = 256)
Shadow
Register
RTC_SS
Shadow
Register
RTC_TIME
RTC_DATE
Backup register
and RTC
tamper control
logic
Time-Stamp
Control logic
Calendar
IRC40K
HXTAL/32
LXTAL(32.768KHz)
RTC_TAMP1
RTC_TAMP0 TPxF
RTC_TS TSF
RTC_REFIN
ck_apre
(Default 256
Hz)
ck_spre
(Default 1 Hz)
Alarm Logic
RTC_ALRM0TD
RTC_ALRM0SS
512Hz
1Hz
=AF
RTC_CALIB
RTC_ALARM
Output Selection
Logic
RTC_OUT
RTC
Block Diagram
The RTC unit includes:
Alarm event/interrupt
Tamper event/interrupt
32-bit backup registers
Optional RTC output function:
- 512Hz (default prescale)
- 1Hz(default prescale)
- Alarm event(polarity is configurable)
Optional RTC input function:
- time stamp event detection: RTC_TS
- tamper 0 event detection: RTC_TAMP0
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- tamper 1 event detection: RTC_TAMP1
- reference clock input: RTC_REFIN(50 or 60 Hz)
20.3.2. RTC pin
PC13, PC14 and PC15 can be directly controlled by RTC through the register RTC_TAMP
and RTC_CTL.
The function priority of PC13 is obey the below table:
PC13
Function
OS
COEN
TP1EN
TSEN
PC13
MODE
PC13
VALUE
RTC_ALARM
output OD
1
X
X
X
X
0
RTC_ALRM
output PP
1
X
X
X
X
1
RTC_CALIB
output PP
0
1
X
X
X
X
RTC_TAMP0
Input Floating
0
0
1
0
X
X
RTC_TS and
RTC_TAMP0
Input Floating
0
0
1
1
X
X
RTC_TS
Input Floating
0
0
0
1
X
X
Output PP
forced
0
0
0
0
1
PC13
value bit
Wakeup pin or
Standard GPIO
0
0
0
0
0
X
Note: (1) OD means open drain, PP means push-pull
(2) ‘X’ means no effect
The function priority of PC14 is obey the below table:
PC14
Function
LXTALEN in
RCU_BDCTL
LXTALBPS in
RCU_BDCTL
PC14
MODE
PC14
VALUE
LXTAL
Oscillator
Analog
Input
1
0
X
X
LXTAL
Bypass
Analog
Input
1
1
X
X
Output PP
0
X
1
PC14 value bit
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forced
Standard
GPIO
0
X
0
X
Note: (1) OD means open drain, PP means push-pull
(2) ‘X’ means no effect
The function priority of PC15 is obey the below table:
PC15
Function
LXTALEN in
RCU_BDCTL
LXTALBPS in
RCU_BDCTL
PC15
MODE
PC15
VALUE
LXTAL
Oscillator
Analog
Input
1
0
X
X
Output PP
forced
1
1
1
PC15 value bit
0
X
Standard
GPIO
0
X
0
X
Note: (1) OD means open drain, PP means push-pull
(2) ‘X’ means no effect
20.3.3. Clock and prescalers
RTC unit has three independent clock sources: LXTAL IRC40K and HXTAL with divided by
32.
In the RTC unit, there are two prescalers used for implementing the calendar and other
functions. One prescaler is a 7-bit asynchronous prescaler and other is a 15-bit synchronous
prescaler. Asynchronous prescaler is mainly used for reducing the power consuming. The
asynchronous prescaler is recommended to set as high as possible if both the prescalers are
used.
The frequency formula of two prescalers are shown as below:
ck_apre rtcclk
_A + 1
ck_spre ck_apre
_S + 1 rtcclk
(_A + 1)*(_S + 1)
The ck_apre clock is used to driven the RTC_SS down counter which stands for the time left
to next second in binary format and when it is reached 0 it will automatically reload to
FACTOR_S. The ck_spre clock is used to driven the calendar registers. Each clock will make
second plus one.
20.3.4. Real-time clock and calendar
BPSHAD control bit decides the location when APB bus accesses the RTC calendar register
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RTC_DATE, RTC_TIME and RTC_SS. By default, the BPSHAD is cleared, and APB bus
accesses the shadow calendar registers. Shadow calendar registers is updated to real
calendar register every two RTC clock and at the same time RSYNF bit is set once. This
update mechanism is not performed in Deep-Sleep mode and Standby mode. When exiting
these modes, software must clear RSYNF bit and wait it is asserted (the max wait time is 2
RTC clock) if software wants to read calendar register under BPSHAD=0 situation.
Note: When reading calendar registers (RTC_SS, RTC_TIME, RTC_DATE) under
BPSHAD=0, the frequency of the APB clock (fAPB) must be at least 7 times the frequency of
the RTC clock (fRTCCLK).
Systerm reset will reset the shadow calendar registers.
20.3.5. Configurable and field maskable alarm
RTC alarm function is divided into some fields and each has a maskable bit.
RTC alarm function can be enabled/disabled by ALRM0EN bit in RTC_CTL. If all the alarm
fields value match the corresponding calendar value when ALRM0EN=1, the ALRM0F flag
will set.
Note: If the seconds field is selected (MSKS bit reset in RTC_ALRM0TD), the synchronous
prescaler division factor value in the RTC_PSC register must be set at least 3 to ensure
correct behavior.
If a field is masked, the field is seen as matched in logic. If all the fields are masked the
ALRM0F will assert 3 RTC clock later after ALRM0EN is set.
20.3.6. RTC initialization and configuration
RTC register write protection
BKPWEN bit in the PMU_CTL register is cleared in default, so writing to RTC registers needs
setting BKPWEN bit ahead of time.
After power-on reset, most of RTC registers are write protected. Unlocking this protection is
the first step before writing to them.
Following below steps will unlock the write protection:
1. Write ‘0xCA’ into the RTC_WPK register
2. Write ‘0x53’ into the RTC_WPK register
Writing a wrong value to RTC_WPK will make write protection valid again. The state of write
protection is not affected by system reset.
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Calendar initialization and configuration
The prescaler and calendar value can be programmed by following steps:
1. Set INITM bit to 1 to enter initialization mode. In this mode, the calendar counter is
stopped and its value can be updated.
2. Circularly reading INITF bit. The initialization phase mode is really entered if INITF is set
to 1. It takes around 2 RTCCLK clock cycles (because of clock synchronization).
3. Program both the asynchronous and synchronous prescaler factors in RTC_PSC register.
4. Write the initial calendar values into the shadow calendar registers (RTC_TIME and
RTC_DATE), and use the CS bit in the RTC_CTL register to configure the time format
(12 or 24 hours).
5. Clear INITM bit for exiting the initialization mode.
About 4 RTCCLK clock cycles later, real calendar registers will load from shadow registers
and calendar counter restarts.
Note: Reading calendar register (BPSHAD=0) after initialization, software should confirm the
RSYNF bit is already set to 1.
YCM flag indicates whether the calendar has been initialized by checking the year field of
calendar is 0x00(YCM=0) or not (YCM=1).
Daylight saving Time
RTC unit supports daylight saving time adjust function through S1H, A1H and DSM bit.
S1H and A1H can subtract or add 1 hour to the calendar when the calendar is running. S1H
and A1H operation can be tautologically set and DSM bit can be used to recording this adjust
operation. After setting the S1H/A1H, subtract/add 1 hour will perform when next second
comes.
Alarm function operation process
To avoid unexpected alarm assertion and metastable state, alarm function has an operation
flow:
1. Clear ALRM0EN in RTC_CTL to disable Alarm
2. Set the Alarm registers needed(RTC_ALRM0SS/ RTC_ALRM0TD)
3. Set ALRM0EN in the RTC_CTL register to enable Alarm function
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20.3.7. Calendar reading
Reading calendar registers under BPSHAD=0
When BPSHAD=0, caldendar is read from shadow registers. For the existence of
synchronization mechanism, a basic request has to meet: the APB1 bus clock frequency must
be equal to or greater than 7 times the RTC clock frequency. APB1 bus clock frequency lower
than RTC clock frequency is not allowed in any case whatever happens.
When APB1 bus clock frequency is not equal to or greater than 7 times the RTC clock, the
calendar reading flow should be obeyed:
1. reading calendar time register and date register twice
2. if the twice value is equal, the value can be seen as the correct value
3. if the twice value is not equal, a third reading should performed
4. the third value can be seen as the correct value
RSYNF is asserted once every 2 RTC clock and at this time point, the shadow calendar
register will be updated to current calendar time and date.
To ensure consistency of the 3 values (RTC_SS, RTC_TIME, RTC_DATE), below consistency
mechanism is used in hardware:
1. reading RTC_SS will lock the updating of RTC_TIME and RTC_DATE
2. reading RTC_TIME will lock the updating of RTC_DATE
3. reading RTC_DATE will unlock updating of RTC_TIME and RTC_DATE
If the software wants to read calendar in a short time interval(smaller than 2 RTCCLK periods),
RSYNF must be cleared by software after the first calendar read, and then the software must
wait until RSYNF is set before reading again.
In below situations, software should wait RSYNF bit asserted be for reading calendar
register(RTC_SS, RTC_TIME, RTC_DATE):
1. after a system reset
2. after an initialization
3. after synchronization
Especially that software must clear RSYNF bit and wait it asserted before reading calendar
register after wakeup from power saving mode.
Reading calendar registers under BPSHAD=1
When BPSHAD=1, RSYNF is cleared and maintained to 0 by hardware so reading calendar
registers does not care about RSYNF bit. Current calendar value is read from real-time
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calendar counter directly. The benefit of this configuration is that software can get the real
current time with no any delay(max to 2 RTC clock) after wakeup from power saving
mode(Deep-sleep /Standby Mode).
Because of no RSYNF bit periodic assertion, the results of the different calendar registers
(RTC_SS/RTC_TIME/RTC_DATE) might not be coherent with each other when clock ck_apre
edge occurs between two reading calendar registers.
In addition, if current calendar register is changing and at the same time the APB bus reading
calendar register is also performing, the value of the calendar register read out might be not
correct.
To ensure the correctness and consistency of the calendar value, software must perform
reading operation as this: read all calendar registers continuously, if the last twice data are
the same, the data is coherent and correct.
20.3.8. Resetting the RTC
There are two reset sources used in RTC unit: system reset and backup domain reset.
System reset will affect calendar shadow registers and some bits of the RTC_STAT. When
system reset is valid, the bits or registers mentioned before are reset to the default value.
Backup domain reset will affect the following registers and system reset will not affect them:
- RTC current real-time calendar registers
- RTC control register (RTC_CTL)
- RTC prescaler register (RTC_PSC)
- RTC high resolution frequency compensation register (RTC_HRFC)
- RTC shift register (RTC_SHIFTCTL)
- RTC timestamp registers (RTC_SSTS/RTC_TTS/RTC_DTS)
- RTC tamper and alternate function configuration register (RTC_TAMP)
- RTC backup registers (RTC_BKPx)
- RTC Alarm registers (RTC_ALRM0SS/RTC_ALRM0TD)
The RTC unit will go on running when system reset occurs or enter power saving mode, but
if backup domain reset occurs, RTC will stop counting and all registers will reset.
20.3.9. RTC synchronization
When the user has a remote clock with higher degree of precision and RTC time has an offset
in a fraction of a second with remote clock, RTC unit provides a function named
synchronization shift to remove this offset and thus make second precision higher.
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RTC_SS register indicates the fraction of a second in binary format and is down counting
when RTC is running. Therefore adding sub-seconds value (by adding the SFS[14:0] value
to the synchronous prescaler counter SSC[15:0]) or subtracting(by adding the SFS[14:0]
value to the synchronous prescaler counter SSC[15:0] and set A1S at the same time) sub-
seconds value can delay or advance the time when next second arrives.
The maximal RTC_SS value depends on the FACTOR_S value in RTC_PSC. The higher is
FACTOR_S, the higher is adjust precision.
Because of the 1Hz clock(ck_spre) is generated by FACTOR_A and FACTOR_S, the higher
FACTOR_S means the lower FACTOR_A and at the same time the lower FACTOR_A means
the higher power consuming.
Note: Before using synchronization shift function, the software must check the 15-bit of SS in
RTC_SS(SSC[15]) and confirm it is 0.
After writing RTC_SHIFTCTL register, the SOPF bit in RTC_STAT will set at once. When
synchronization shift operation is complete, SOPF bit is cleared by hardware. System reset
does not affect SOPF bit.
Synchronization shift operation only works correctly when REFEN=0.
Software must not write to RTC_SHIFTCTL if REFEN=1.
20.3.10. RTC reference clock detection
RTC reference clock detection is another way supported to increase the precision of RTC
second. To enable this function, you should has a external clock source(50Hz or 60 Hz) which
has the higher precision than LXTAL clock source.
After enabling this function (REFEN=1), each second update clock(1Hz) edge is compared
to the nearest RTC_REFIN clock edge. In most cases, the two clock edges are aligned every
time. But when two clock edge are misaligned for the reason of LXTAL precision, the RTC
reference clock detection function will shift the 1Hz clock edge a little to make future 1Hz
aligned to reference clock edge.
When REFEN=1, a time window around every second update time for detection is performed.
Different detection state will use different window period.
7 ck_apre window periods are used when the detection state is detecting the first reference
clock edge and 3 ck_apre window periods are used for the edge aligned operation.
Whatever window used, the asynchronous prescaler counter will be forced to reload when
the reference clock is detected in the window. When the two clock(ck_spre and reference
clock) edge are aligned, this reload operation has no any effect for 1Hz calendar updating
clock. But when the two clock edge are not aligned, this reload operation will shift ck_spre
clock edge a bit to make the ck_spre(1Hz) clock edge aligned to the reference clock edge.
When reference detection function is running and the external reference clock removed(no
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reference clock edge found in 3 ck_apre window), the calendar updating also can be
performed by LXTAL clock only. If the reference clock is recovered later, detection function
will use 7 ck_apre window to identify the reference clock and use 3 ck_apre window to adjust
the ck_spre(1Hz) clock edge.
Note: Software must configure the FACTOR_A to 0x7F and FACTOR_S to 0xFF before
enabling reference detection function(REFEN=1)
Reference detection function does not work in Standby Mode.
20.3.11. RTC smooth digital calibration
RTC calibration function is a way to calibrate the RTC frequency based RTC clock cycle
number in a configurable period time.
This calibration is equally executed in a period time and after finish calibrating once, the cycle
number of the RTC clock in the period time will be added or subtracted some individual
RTCCLK cycles. The resolution of the calibration is about 0.954ppm with the range from -
487.1ppm to +488.5ppm.
The calibration period time can be configured to the 220/219/218 RTC clock cycles which
stands for 32/16/8 seconds if RTC input frequency is 32.768KHz.
The calibration configure register (RTC_HRFC) specifies the number of RTCCLK clock cycles
to be calibrated during the period time:
Setting CMSK[0] to 1 causes 1 cycle to be masked during the period time
Setting CMSK[1] to 1 causes 2 additional cycles to be masked
Setting CMSK[2] to 1 causes 4 additional cycles to be masked
Setting CMSK[8] to 1 causes 256 additional cycles to be masked
So using CMSK can mask clock cycles from 0 to 511 and thus the RTC frequency can be
reduced by up to 487.1ppm.
To increase the RTC frequency the FREQI bit can be set. If FREQI bit is set, there will be 512
additional cycles to be added during period time which means every 211/210/29(32/16/8
seconds) RTC clock insert one cycle.
So using FREQI can increase the RTC frequency by 488.5ppm.
The combined using of CMSK a FREQI can adjust the RTC cycles from -511 to +512 cycles
in the period time which means the calibration range is -487.1ppm to +488.5ppm with a
resolution of about 0.954ppm.
When calibration function is running, the output frequency of calibration is calculated by the
following formula:
fcal=frtcclk*[1+(FREQI×512-CMSK)/(2N +CMSK-FREQI×512)]
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Note: N=20/19/18 for 32/16/8 seconds window period
Calibration when FACTOR_A < 3
When asynchronous prescaler value (FACTOR_A) is set to less than 3, software should not
set FREQI bit to 1 when using calibration function. FREQI setting will be ignored when
FACTOR_A<3.
When the FACTOR_A is less than 3, the FACTOR_S value should be set to a value less than
the nominal value. Assuming that RTC clock frequency is nominal 32.768KHz, the
corresponding FACTOR_S should be set as following rule:
FACTOR_A = 2: 2 less than nominal FACTOR_S(8189 with 32.768KHz)
FACTOR_A = 1: 4 less than nominal FACTOR_S(16379 with 32.768KHz)
FACTOR_A = 0: 8 less than nominal FACTOR_S(32759 with 32.76KHz)
When the FACTOR_A is less than 3,the formula of calibration frequency is as follows:
fcal=frtcclk*[1+(256-CMSK)/(2N +CMSK-256)]
Note: If FACTOR_A is less than 3, the calibration midpoint of CMSK is 0x100 when RTC clock
is exactly 32.768KHz.
Verifying the RTC calibration
Calibration 1Hz output is provided to assist software to measure and verify the RTC precision.
Up to 2 RTCCLK clock cycles measurement error may occur when measuring the RTC
frequency over a limited measurement period. To eliminate this measurement error the
measurement period should be the same as the calibration period.
When the calibration period is 32 seconds(this is default configuration)
Using exactly 32s period to measure the accuracy of the calibration 1Hz output can guarantee
the measure is within 0.477ppm(0.5 RTCCLK cycles over 32s)
When the calibration period is 16 seconds(by setting CWND16 bit)
In this configuration, CMSK[0] is fixed to 0 by hardware.Using exactly 16s period to measure
the accuracy of the calibration 1Hz output can guarantee the measure is within 0.954ppm(0.5
RTCCLK cycles over 16s)
When the calibration period is 8 seconds(by setting CWND8 bit)
In this configuration, CMSK[1:0] is fixed to 0 by hardware.Using exactly 8s period to measure
the accuracy of the calibration 1Hz output can guarantee the measure is within 1.907ppm(0.5
RTCCLK cycles over 8s)
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Re-calibration on-the-fly
When the INITF bit is 0, software can update the value of RTC_HRFC using following steps:
1) Wait the SCPF bit is set to 0
2) Write the new value into RTC_HRFC register
3) After 3 ck_apre clocks, the new calibration settings take effect
20.3.12. Time-stamp function
Time-stamp function is performed on RTC_TS pin and is enabled by control bit TSEN.
When a time-stamp event occurs on RTC_TS pin, the calendar value will be saved in time-
stamp registers(RTC_DTS/RTC_TTS/RTC_SSTS) and the time-stamp flag(TSF) is set to 1
by hardware. Time-stamp event can generate an interrupt if time-stamp interrupt enable(TSIE)
is set.
Time-stamp registers only record the calendar at the first time time-stamp event occurs which
means that time-stamp registers will not change when TSF=1.
To extend the time-stamp event source, one optional feature is provided: tamper function can
also be seen as time-stamp function if TPTS is set.
Note: When the time-stamp event occurs, TSF is set 2 ck_apre cycles delay because of
synchronization mechanism.
20.3.13. Tamper detection
The RTC_TAMPx pin input can be used for tamper event detection under edge detection
mode or level detection mode with configurable filtering setting.
RTC backup registers(RTC_BKPx)
The RTC backup registers are located in the VDD backup domain that remains powered-on by
VBAT even if VDD power is switched off. The wake up action from Standby Mode or system
reset are not affect these registers.
These registers are only affected to reset by detected tamper event or when reading
protection of the flash is changed from level 1 to level 0.
Tamper detection function initialization
RTC tamper detection function can be independently enabled on tamper input pin by setting
corresponding TPxEN bit. Tamper detection configuration is set before enable TPxEN
bit.When the tamper event is detected, the corresponding flag(TPxF) will assert.Tamper event
can generate an interrupt if tamper interrupt enable(TPIE) is set. Any tamper event will reset
all backup registers(RTC_BKPx).
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Timestamp on tamper event
The TPTS bit can control whether the tamper detection function is used as time-stamp
function. If the bit is set to 1, the TSF bit will be set when the tamper event detected as if
“enable” the time-stamp function. Whatever the TPTS bit is, the TPxF will assert when tamper
event detected.
Edge detection mode on tamper input detection
When FLT bit is set to 0x0, the tamper detection is set to edge detection mode and TPxEG
bit determines the rising edge or falling edge is the detecting edge. When tamper detection is
under edge detection mode, the internal pull-up resistors on the tamper detection input pin
are deactivated.
Because of detecting the tamper event will reset the backup registers(RTC_BKPx), writing to
the backup register should ensure that the tamper event reset and the writing operation will
not occur at the same time, a recommend way to avoid this situation is disable the tamper
detection before writing to the backup register and re-enable tamper detection after finish
writing.
Note: Tamper detection is still running on tamper0 (PC13) when VDD power is switched off if
tamper0 is enabled.
Level detection mode with configurable filtering on tamper input detection
When FLT bit is not set to 0x0, the tamper detection is set to level detection mode and FLT
bit determines the consecutive number of time(2,4 or 8) for sampling.When DISPU is set to
0(this is default), the internal pull-up resistance will pre-charge the tamper input pin before
each sampling and thus larger capacitance is allowed to connect to the tamper input pin. The
pre-charge duration is configured through PRCH bit. Higher capacitance needs long pre-
charge time.
The interval time between each sampling is also configurable. Through adjusting the sampling
frequency(FREQ), software can balance between the power consuming and tamper detection
latency.
20.3.14. Calibration clock output
Calibration reference clock can be output on the PC13 if COEN bit is set to 1.
When the COS bit is set to 0(this is default) and asynchronous prescaler is set to
0x7F(FACTOR_A), the frequency of RTC_CALIB is fRTCCLK/64.When the RTCCLK is
32.768KHz, RTC_CALIB output is corresponding to 512Hz.It’s recommend to using rising
edge of RTC_CALIB output for there are maybe a light jitter on falling edge.
When the COS bit is set to 1, the RTC_CALIB frequency is ：
fRTCCLK/((FACTOR_S+1)*(FACTOR_A+1))
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When the RTCCLK is 32.768KHz, RTC_CALIB output is corresponding to 1Hz if prescaler
are default values.
20.3.15. Alarm output
When OS control bits are set to 0x01, RTC_ALARM alternate function output is enabled. This
function will directly output the content of ALRM0F bit in RTC_STAT.
The OPOL bit in RTC_CTL can configure the polarity of the ALRM0F output which means that
whether the RTC_ALARM output is the opposite of ALRM0F bit.
20.3.16. RTC power saving mode management
Mode
Active in Mode
Exit Mode
Sleep
Yes
RTC interrupts
Deep-
sleep
Yes: if clock source
is LXTAL or IRC40K
RTC alarm/tamper event/timestamp event
Standby
Yes: if clock source
is LXTAL or IRC40K
RTC alarm/tamper event/timestamp event
20.3.17. RTC interrupts
All RTC interrupts are connected to the EXTI controller.
Below steps should be followed if you want to use the RTC alarm/tamper/timestamp interrupt:
1) Configure and enable the corresponding line to RTC alarm/tamper/timestamp event of
EXIT and set the rising edge for triggering
2) Configure and enable the RTC global interrupt
3) Configure and enable the RTC alarm/tamper/timestamp function
Interrupt
Event flag
Control Bit
Exit
Sleep
Exit Deep-
sleep
Exit
Standby
Alarm
ALRM0F
ALRM0IE
Y
Y(*)
Y(*)
Timestamp
TSF
TSIE
Y
Y(*)
Y(*)
Tamper 0
TP0F
TPIE
Y
Y(*)
Y(*)
Tamper 1
TP1F
TPIE
Y
Y(*)
Y(*)
Note: Only active when RTC clock source is LXTAL or IRC40K
20.4. RTC registers
20.4.1. Time of day register (RTC_TIME)
Address offset: 0x00
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System reset value: 0x0000 0000 when BPSHAD = 0.
Not affected when BPSHAD = 1.
This register is write protected and can only be written in initialization state
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
PM
HRT[1:0]
HRU[3:0]
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
MNT[2:0]
MNU[3:0]
Reserved
SCT[2:0]
SCU[3:0]
rw
rw
rw
rw
Bits
Fields
Descriptions
31:23
Reserved
Must be kept at reset value
22
PM
AM/PM mark
0: AM or 24-hour format
1: PM
21:20
HRT[1:0]
Hour tens in BCD code
19:16
HRU[3:0]
Hour units in BCD code
15:
Reserved
Must be kept at reset value
14:12
MNT[2:0]
Minute tens in BCD code
11:8
MNU[3:0]
Minute units in BCD code
7
Reserved
Must be kept at reset value
6:4
SCT[2:0]
Second tens in BCD code
3:0
SCU[3:0]
Second units in BCD code
20.4.2. Date register (RTC_DATE)
Address offset: 0x04
System reset value: 0x0000 2101 when BPSHAD = 0.
Not affected when BPSHAD = 1.
This register is write protected and can only be written in initialization state
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
YRT[3:0]
YRU[3:0]
rw
rw
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15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
DOW[2:0]
MONT
MONU[3:0]
Reserved
DAYT[1:0]
DAYU[3:0]
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31:24
Reserved
Must be kept at reset value
23:20
YRT[3:0]
Year tens in BCD code
19:16
YRU[3:0]
Year units in BCD code
15:13
DOW[2:0]
Days of the week
0x0: Reserved
0x1: Monday
…
0x7: Sunday
12
MONT
Month tens in BCD code
11:8
MONU[2:0]
Month units in BCD code
7:6
Reserved
Must be kept at reset value
5:4
DAYT[1:0]
Date tens in BCD code
3:0
DAYU[3:0]
Date units in BCD code
20.4.3. Control register (RTC_CTL)
Address offset: 0x08
System reset: not affected
Backup domain reset value: 0x0000 0000
This register is write protected
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
COEN
OS[1:0]
OPOL
COS
DSM
S1H
A1H
rw
rw
rw
rw
rw
w
w
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
TSIE
Reserved
ALRM0IE
TSEN
Reserved
ALRM0EN
Reserved
CS
BPSHAD
REFEN
TSEG
Reserved
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31:24
Reserved
Must be kept at reset value
23
COEN
Calibration output enable
0: Disable calibration output
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1: Enable calibration output
22:21
OS[1:0]
Output selection
This bit is used for selecting flag source of RTC_ALARM output
0x0: Disable output RTC_ALARM
0x1: Enable alarm flag output
0x2: Reserved
0x3: Reserved
20
OPOL
Output polarity
This bit is used to invert output RTC_ALARM
0: Disable invert output RTC_ALARM
1: Enable invert output RTC_ALARM
19
COS
Calibration output selection
Valid only when COEN=1 and prescalers are at default values
0: Calibration output is 512 Hz
1: Calibration output is 1Hz
18
DSM
Daylight saving mark
This bit is flexible used by software. Often can be used to recording the daylight saving
hour adjust.
17
S1H
Subtract 1 hour(winter time change)
One hour will be subtracted from now time if now hour time is not 0
0: No effect
1: 1 hour will be subtracted at next second change time.
16
A1H
Add 1 hour(summer time change)
One hour will be added from now time
0: No effect
1: 1 hour will be added at next second change time
15
TSIE
Time-stamp interrupt enable
0: Disable time-stamp interrupt
1: Enable time-stamp interrupt
14:13
Reserved
Must be kept at reset value
12
ALRM0IE
RTC alarm-0 interrupt enable
0: Disable alarm interrupt
1: Enable alarm interrupt
11
TSEN
time-stamp function enable
0: Disable time-stamp function
1: Enable time-stamp function
10:9
Reserved
Must be kept at reset value
8
ALRM0EN
Alarm-0 function enable
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0: Disable alarm function
1: Enable alarm function
7
Reserved
Must be kept at reset value
6
CS
Clock System
0: 24-hour format
1: 12-hour format
Note: Can only be written in initialization state
5
BPSHAD
Shadow registers bypass control
0: Reading calendar from shadow registers
1: Reading calendar from current real-time calendar
Note: If frequency of APB1 clock is less than seven times the frequency of RTCCLK,
this bit must set to 1.
4
REFEN
Reference clock detection function enable
0: Disable reference clock detection function
1: Enable reference clock detection function
Note: Can only be written in initialization state
3
TSEG
Valid event edge of time-stamp
0: rising edge is valid event edge for time-stamp event
1: falling edge is valid event edge for time-stamp event
2:0
Reserved
Must be kept at reset value
20.4.4. Status register (RTC_STAT)
Address offset: 0x0C
System reset: Only INITM, INITF and RSYNF bit are set to 0. others are not affected
Backup domain reset value: 0x0000 0007
This register is write protected except RTC_STAT[14:8].
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
SCPF
r
15
14
13
12
11
10 9
8
7
6
5
4
3
2 1
0
Res.
TP1F
TP0F
TSOVRF
TSF
Reserved
ALRM0F
INITM
INITF
RSYNF
YCM
SOPF
Res.
ALRM0WF
rc_w0
rc_w0
rc_w0
rc_w0
rc_w0
rw
r
rc_w0
r
rc_w0
r
Bits
Fields
Descriptions
31:17
Reserved
Must be kept at reset value
16
SCPF
Smooth calibration pending flag
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Set to 1 by hardware when software writes to RTC_HRFC and set to 0 by hardware
when calibration configuration is taken into account.
15
Reserved
Must be kept at reset value
14
TP1F
RTC_TAMP1 detected flag
Set to 1 by hardware when tamper detection is found on tamper1 input pin. Software
can clear this bit by writing 0 into this bit.
13
TP0F
RTC_TAMP0 detected flag
Set to 1 by hardware when tamper detection is found on tamper0 input pin. Software
can clear this bit by writing 0 into this bit.
12
TSOVRF
Time-stamp overflow flag
This bit is set by hardware when a time-stamp event is detected if TSF bit is set
before.
Cleared by software writing 0.
11
TSF
Time-stamp flag
Set by hardware when time-stamp event is detected.
Cleared by software writing 0.
10:9
Reserved
Must be kept at reset value
8
ALRM0F
Alarm-0 occurs flag
Set to 1 by hardware when now time/date matches the time/date of alarm setting
value.
Cleared by software writing 0.
7
INITM
enter initialization mode
0: Free running mode
1: Enter initialization mode for setting calendar time/date and prescaler. Counter will
stop under this mode.
6
INITF
Initialization state flag
Set to 1 by hardware and calendar register and prescaler can be programmed in
this state.
0: Calendar registers and prescaler register cannot be changed
1: Calendar registers and prescaler register can be changed
5
RSYNF
Register synchronization flag
Set to 1 by hardware every 2 RTCCLK which will copy current calendar time/date
into shadow register. Initialization mode(INITM), shift operation pending flag(SOPF)
or bypass mode(BPSHAD) will clear this bit. This bit is also can be cleared by
software writing 0.
0: Shadow register are not yet synchronized
1: Shadow register are synchronized
4
YCM
Year configuration mark
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Set by hardware if the year field of calendar date register is not the default value 0.
0: Calendar has not been initialized
1: Calendar has been initialized
3
SOPF
Shift function operation pending flag
0: No shift operation is pending
1: Shift function operation is pending
2:1
Reserved
Must be kept at reset value
0
ALRM0WF
Alarm 0 configuration can be write flag
Set by hardware if alarm register can be write after ALRM0EN bit has reset.
0: Alarm registers programming is not allowed
1: Alarm registers programming is allowed
20.4.5. Time prescaler register (RTC_PSC)
Address offset: 0x10
System reset: not effected
Backup domain reset value: 0x007F 00FF
This register can only be wrote in initialization mode.
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
FACTOR_A[6:0]
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Res
FACTOR_S[14:0]
rw
Bits
Fields
Descriptions
31:23
Reserved
Must be kept at reset value
22:16
FACTOR_A[6:0]
Asynchronous prescaler factor
ck_apre frequency = RTCCLK frequency/(FACTOR_A+1)
15
Reserved
Must be kept at reset value
14:0
FACTOR_S[14:0]
synchronous prescaler factor
ck_spre frequency = ck_apre frequency/(FACTOR_S+1)
20.4.6. Alarm 0 Time and date register (RTC_ALRM0TD)
Address offset : 0x1C
System reset : not effected
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Backup domain reset value: 0x0000 0000
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
MSKD
DOWS
DAYT[1:0]
DAYU[3:0]
MSKH
PM
HRT[1:0]
HRU[3:0]
rw
rw
rw
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
MSKM
MNT[2:0]
MNU[3:0]
MSKS
SCT[2:0]
SCU[3:0]
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31
MSKD
Alarm date mask bit
0: Not mask date/day field
1: Mask date/day field
30
DOWS
Day of the week selected
0: DAYU[3:0] indicates the date units
1: DAYU[3:0] indicates the week day and DAYT[3:0] has no means.
29:28
DAYT[1:0]
Date tens in BCD code
27:24
DAYU[3:0]
Date units or week day in BCD code
23
MSKH
Alarm hour mask bit
0: Not mask hour field
1: Mask hour field
22
PM
AM/PM flag
0: AM or 24-hour format
1: PM
21:20
HRT[1:0]
Hour tens in BCD code
19:16
HRU[3:0]
Hour units in BCD code
15
MSKM
Alarm minutes mask bit
0: Not mask minutes field
1: Mask minutes field
14:12
MNT[2:0]
Minutes tens in BCD code
11:8
MNU[3:0]
Minutes units in BCD code
7
MSKS
Alarm second mask bit
0: Not mask second field
1: Mask second field
6:4
SCT[2:0]
Second tens in BCD code
3:0
SCU[3:0]
Second units in BCD code
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20.4.7. Write protection key register (RTC_WPK)
Address offset : 0x24
Reset value : 0x0000 0000
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
WPK[7:0]
w
Bits
Fields
Descriptions
31:8
Reserved
Must be kept at reset value
7:0
WPK[7:0]
Key for write protection
20.4.8. Sub second register (RTC_SS)
Address offset: 0x28
System reset value: 0x0000 0000 when BPSHAD = 0.
Not affected when BPSHAD = 1.
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
SSC[15:0]
r
Bits
Fields
Descriptions
31:16
Reserved
Must be kept at reset value
15:0
SSC[15:0]
Sub second value
This value is the counter value of synchronous prescaler. Second fraction value is
calculated by the below formula:
Second fraction = ( FACTOR_S - SSC ) / ( FACTOR_S + 1 )
20.4.9. Shift function control register (RTC_SHIFTCTL)
Address offset: 0x2C
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Reset value: 0x0000 0000
This register can only be wrote when SOPF=0
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
A1S
Reserved
w
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
SFS[14:0]
w
Bits
Fields
Descriptions
31
A1S
One second add
0: Not add 1 second
1: Add one second to the clock/calendar.
This bit is jointly use with SFS bit to add a fraction of a second to the clock.
30:15
Reserved
Must be kept at reset value
14:0
SFS[14:0]
Subtract a fraction of a second
The value of this bit will add to the counter of synchronous prescaler.
When just only use SFS, the clock will delay because the synchronous prescaler is
a down counter:
Delay (seconds) = SFS / ( FACTOR_S + 1 )
When jointly use A1S and SFS, the clock will advance:
Advance (seconds) = ( 1 - ( SFS / ( FACTOR_S + 1 ) ) )
Note: Writing to this register will cause RSYNF bit to be cleared.
20.4.10. Time of time stamp register (RTC_TTS)
Address offset: 0x30
Backup domain reset value: 0x0000 0000
System reset: no effect
This register will record the calendar time when TSF is set to 1.
Reset TSF bit will also clear this register.
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
PM
HRT[1:0]
HRU[3:0]
r
r
r
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
MNT[2:0]
MNU[3:0]
Reserved
SCT[2:0]
SCU[3:0]
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r
r
r
r
Bits
Fields
Descriptions
31:23
Reserved
Must be kept at reset value
22
PM
AM/PM mark
0: AM or 24-hour format
1: PM
21:20
HRT[1:0]
Hour tens in BCD code
19:16
HRU[3:0]
Hour units in BCD code
15
Reserved
Must be kept at reset value
14:12
MNT[2:0]
Minute tens in BCD code
11:8
MNU[3:0]
Minute units in BCD code
7
Reserved
Must be kept at reset value
6:4
SCT[2:0]
Second tens in BCD code
3:0
SCU[3:0]
Second units in BCD code
20.4.11. Date of time stamp register (RTC_DTS)
Address offset: 0x34
Backup domain reset value: 0x0000 0000
System reset: no effect
This register will record the calendar date when TSF is set to 1.
Reset TSF bit will also clear this register.
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
DOW[2:0]
MONT
MONU[3:0]
Reserved
DAYT[1:0]
DAYU[3:0]
r
r
r
r
r
Bits
Fields
Descriptions
31:16
Reserved
Must be kept at reset value
15:13
DOW[2:0]
Week day units
12
MONT
Month tens in BCD code
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11:8
MONU[3:0]
Month units in BCD code
7:6
Reserved
Must be kept at reset value
5:4
DAYT[1:0]
Date tens in BCD code
3:0
DAYU[3:0]
Date units in BCD code
20.4.12. Sub second of time stamp register (RTC_SSTS)
Address offset: 0x38
Backup domain reset: 0x0000 0000
System reset: no effect
This register will record the calendar date when TSF is set to 1.
Reset TSF bit will also clear this register.
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
SSC[15:0]
r
Bits
Fields
Descriptions
31:16
Reserved
Must be kept at reset value
15:0
SSC[15:0]
Sub second value
This value is the counter value of synchronous prescaler when TSF is set to 1.
20.4.13. High resolution frequency compensation registor (RTC_HRFC)
Address offset: 0x3C
Backup domain reset: 0x0000 0000
System Reset: no effect
This register is write protected.
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
FREQI
CWND8
CWND16
Reserved
CMSK[8:0]
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rw
rw
rw
rw
Bits
Fields
Descriptions
31:16
Reserved
Must be kept at reset value
15
FREQI
Increase RTC frequency by 488.5ppm
0: No effect
1: One RTCCLK pulse is equivalently inserted every 211 pulses.
This bit should be used in conjunction with CMSK bit. If the input clock frequency is
32.768KHz, the number of RTCCLK pulses added during 32s calibration window is
(512 * FREQI) - CMSK
14
CWND8
Frequency compensation window 8 second selected
0: No effect
1: Calibration window is 8 second
Note: When CWND8=1, CMSK[1:0] are stuck at “00”.
13
CWND16
Frequency compensation window 16 second selected
0: No effect
1: Calibration window is 16 second
Note: When CWND16=1, CMSK[0] are stuck at “0”.
12:9
Reserved
Must be kept at reset value
8:0
CMSK[8:0]
Calibration mask number
The number of mask pulse out of 220 RTCCLK pulse.
This feature will decrease the frequency of calendar with a resolution of 0.9537 ppm.
20.4.14. Tamper register (RTC_TAMP)
Address offset: 0x40
Backup domain reset: 0x0000 0000
System reset : no effect
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
PC15MDE
PC15VAL
PC14MDE
PC14VAL
PC13MDE
PC13VAL
Reserved
rw
rw
rw
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
DISPU
PRCH[1:0]
FLT[1:0]
FREQ[2:0]
TPTS
Reserved
TP1EG
TP1EN
TPIE
TP0EG
TP0EN
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31:24
Reserved
Must be kept at reset value
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23
PC15MDE
PC15 mode
0: PC15 is controlled by GPIO configuration.
1: PC15 is forced to push-pull output if LXTALEN=0.
22
PC15VAL
PC15 value
PC15 outputs this value when PC15MDE=1 and LXTALEN=0.
21
PC14MDE
PC14 mode
0: PC14 is controlled by GPIO configuration.
1: PC14 is forced to push-pull output if LXTALEN=0.
20
PC14VAL
PC14 value
PC14 outputs this value when PC14MODE=1 and LXTALEN=0.
19
PC13MDE
0: PC13 is controlled by GPIO configuration.
1: PC13 is forced to push-pull output if all RTC alternate functions are disabled..
18
PC13VAL
Alarm output type control/PC13 output value
When RTC alternate function enabled, output RTC_ALARM:
0: RTC_ALARM output is open-drain mode
1: RTC_ALARM output is push-pull mode
When all RTC alternate function are disabled and PC13MODE=1,this bit control the
PC13 output value
17:16
Reserved
Must be kept at reset value
15
DISPU
RTC_TAMPx pull up disable bit
0:Enable inner pull-up before sampling for precharge RTC_TAMPx pin
1:Disable precharge duration
14:13
PRCH[1:0]
Precharge duration time of RTC_TAMPx
This setting determines the prechagre time before each sampling.
0x0: 1 RTC clock
0x1: 2 RTC clock
0x2: 4 RTC clock
0x3: 8 RTC clock
12:11
FLT[1:0]
RTC_TAMPx filter count setting
This bit determines the tamper sampling type and the number of consecutive
sample.
0x0: Detecting tamper event using edge mode. Precharge duration is disabled
automatically
0x1: Detecting tamper event using level mode.2 consecutive valid level samples
will make a effective tamper event
0x2: Detecting tamper event using level mode.4 consecutive valid level samples
will make an effective tamper event
0x3: Detecting tamper event using level mode.8 consecutive valid level samples
will make a effective tamper event
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10:8
FREQ[2:0]
Sample frequency of tamper event detection
0x0: Sample once every 32768 RTCCLK(1Hz if RTCCLK=32.768KHz)
0x1: Sample once every 16384 RTCCLK(2Hz if RTCCLK=32.768KHz)
0x2: Sample once every 8192 RTCCLK(4Hz if RTCCLK=32.768KHz)
0x3: Sample once every 4096 RTCCLK(8Hz if RTCCLK=32.768KHz)
0x4: Sample once every 2048 RTCCLK(16Hz if RTCCLK=32.768KHz)
0x5: Sample once every 1024 RTCCLK(32Hz if RTCCLK=32.768KHz)
0x6: Sample once every 512 RTCCLK(64Hz if RTCCLK=32.768KHz)
0x7: Sample once every 256 RTCCLK(128Hz if RTCCLK=32.768KHz)
7
TPTS
Make tamper function used for timestamp function
0: No effect
1: TSF is set when tamper event detected even TSEN=0
6:5
Reserved
Must be kept at reset value
4
TP1EG
Tamper 1 event trigger edge for RTC_TAMP1 input
If tamper detection is in edge mode(FLT =0):
0: Rising edge triggers a tamper detection event
1: Falling edge triggers a tamper detection event
If tamper detection is in level mode(FLT ≠0):
0: Low level triggers a tamper detection event
1: High level triggers a tamper detection event
3
TP1EN
Tamper 1 detection enable
0: Disable tamper 1 detection function
1:Enable tamper 1 detection function
2
TPIE
Tamper detection interrupt enable
0: Disable tamper interrupt
1: Enable tamper interrupt
1
TP0EG
Tamper 0 event trigger edge for RTC_TAMP0 input
If tamper detection is in edge mode(FLT =0):
0: Rising edge triggers a tamper detection event
1: Falling edge triggers a tamper detection event
If tamper detection is in level mode(FLT !=0):
0: Low level triggers a tamper detection event
1: High level triggers a tamper detection event
0
TP0EN
Tamper 0 detection enable
0: Disable tamper 0 detection function
1: Enable tamper 0 detection function
Note: It’s strongly recommended that reset the TAMPxE before change the tamper configuration.
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20.4.15. Alarm 0 sub second register (RTC_ALRM0SS)
Address offset: 0x44
Backup domain reset: 0x0000 0000
System reset: no effect
This register is write protected and can only be wrote when ALRM0EN=0 or INITM=1
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
MSKSSC[3:0]
Reserved
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
SSC[14:0]
rw
Bits
Fields
Descriptions
31:28
Reserved
Must be kept at reset value
27:24
MSKSSC[3:0]
Mask control bit of SSC
0x0: Mask alarm sub second setting. The alarm asserts at every second time point
if all the rest alarm fields are matched.
0x1: SSC[0] is to be compared and all others are ignored
0x2: SSC[1:0] is to be compared and all others are ignored
0x3: SSC[2:0] is to be compared and all others are ignored
0x4: SSC[3:0] is to be compared and all others are ignored
0x5: SSC[4:0] is to be compared and all others are ignored
0x6: SSC[5:0] is to be compared and all others are ignored
0x7: SSC[6:0] is to be compared and all others are ignored
0x8: SSC[7:0] is to be compared and all others are ignored
0x9: SSC[8:0] is to be compared and all others are ignored
0x10: SSC[9:0] is to be compared and all others are ignored
0x11: SSC[10:0] is to be compared and all others are ignored
0x12: SSC[11:0] is to be compared and all others are ignored
0x13: SSC[12:0] is to be compared and all others are ignored
0x14: SSC[13:0] is to be compared and all others are ignored
0x15: SSC[14:0] is to be compared and all others are ignored
Note: The bit 15 of synchronous counter(SSC[15] in RTC_SS) is never compared.
23:15
Reserved
Must be kept at reset value
14:0
SSC[14:0]
Alarm sub second value
This value is the alarm sub second value which is to be compared with
synchronous prescaler counter SSC. Bit number is controlled by MSKSSC bit.
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20.4.16. Backup register (RTC_BKPx)(x=0,1,2,3,4)
Address offset: 0x50 to 0x60
Backup domain reset: 0x0000 0000
System reset: no effect
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
DATA[31:16]
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
DATA[15:0]
rw
Bits
Fields
Descriptions
31:0
DATA[31:0]
Backup domain registers.
These registers can be wrote or read by software. The content remains valid even
in power saving mode because they can powered-on by VBAT. Tamper detection
flag TPxF assertion or disable Flash readout protection will reset these registers.
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21. Touch sensing interface(TSI)
21.1. Introduction
Touch Sensing Interface (TSI) provides a convenient solution for touch keys, sliders and
capacitive proximity sensing applications. The controller builds on charge transfer method.
Placing a finger near fringing electric fields adds capacitance to the system and TSI is able to
measure this capacitance change using charge transfer method.
21.2. Main features
Transfer sequence fully controlled by hardware
6 fully parallel groups implemented
18 IOs configurable for capacitive sensing Channel Pins and 6 for Sample Pins
Configurable transfer sequence frequency
Possible to implement the user specific transfer sequences
Sequence end and error flags / configurable interrupts
Spread spectrum function implemented
21.3. Function description
21.3.1. TSI block diagram
Figure 21-1. Block diagram of TSI module
TSI registers
AHB Bus
Group 0 IO
Controller
Pulse Clock
Generators
G0_IO0
Transfer
Sequence FSM
G0_IO3
G0_IO2
G0_IO1
Group 1 IO
Controller
G1_IO0
G1_IO3
G1_IO2
G1_IO1
Group 5 IO
Controller
G5_IO0
G5_IO3
G5_IO2
G5_IO1
TSI Counters
21.3.2. Touch sensing technique overview
There are different technologies for touch sensing, such as optical, resistive, capacitive, strain,
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582
etc. Detecting the change of a system is the key problem and goal in these technologies. The
TSI module is designed to use charge transfer method which detects the capacitive change
of an electrode when touched by or a finger close to it. In order to detect the capacitive change,
TSI performs a charge transfer sequence including several charging, transfer steps. The
number of these steps indicates the capacitance of an electrode. So the application is able to
detect the change of capacitance by monitoring the step number of each transfer sequence.
As shown in Figure 21-2, there are 4 PINs in one group and each PIN has an analog switch
connected to a common point which is the key component to implement charge transfer.
There should be a sample pin and one or more channel pin(s) configured in one group. In
Figure 21-2, PIN0 is a channel pin and PIN1 is a sample pin while PIN2 and PIN3 are unused.
An electrode connecting PIN0 is designed on PCB board. The A sample
capacitorconnected to sample pin PIN1 is also required. Now the capacitance of the
channel pin PIN0 includes  and the capacitance introduced by the electrode, so
capacitance of PIN0 increases when a finger is touching while the capacitance of PIN1
remains unchanged. Thus, the finger’s touching can be detected if the capacitance of PIN0
can be measured. In TSI module, a charge-transfer sequence is performed to measure the
capacitance of the channel pin(s) in a group, which will be detailed in next section.
Figure 21-2. Block diagram of Sample pin and Channel Pin
CX
Electrode
CS
ASW_0
PIN0 PIN1
ASW_1 ASW_2
PIN2 PIN3
ASW_3
Chip
21.3.3. Charge transfer sequence
In order to measure the capacitance of a channel pin, charge transfer sequence is performed
in chip. The sequence shown in Table 21-1 is described based on the connection of Figure
21-2, i.e. PIN0 is channel pin and PIN1 is sample pin.
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Table 21-1. Pin and analog switch state in a charge-transfer sequence
Step
Name
ASW_0
ASW_1
Pin0
Pin1
1
Discharge
Close
Close
Input Floating
Pull Down
2
Buffer Time1
Open
Open
Input Floating
Input Floating
3
Charge
Open
Open
Output High
Input Floating
4
Extend Charge
Open
Open
Output High
Input Floating
5
Buffer Time2
Open
Open
Input Floating
Input Floating
6
Charge Transfer
Close
Close
Input Floating
Input Floating
7
Buffer Time3
Open
Open
Input Floating
Input Floating
8
Compare
Open
Open
Input Floating
Input Floating
1. Discharge
Both and are discharged by closing ASW_0 and ASW_1 and configuring PIN1 to pull
down. This step is the initial operation for a correct charge transfer sequence and is performed
by software before starting a charge transfer sequence. Discharging time in this step should
be guaranteed to ensure that the voltage of and are discharged to zero.
2. Buffer Time1
Buffer time with ASW_0 and ASW_1 open, PIN0 is configured to input floating.
3. Charge
Channel pin PIN0 is configured to output high, in order to charge . ASW_0 and ASW_1
remain open during this step. The charging time should be configured (see Register Section
for detail) to ensure that the voltage of is charged to VDD.
4. Extend Charge
This is an optional step in a charge-transfer sequence and the behavior of all pins and analog
switches in this step is the same as Step 3. The only difference between this and step 3 is the
duration time, which is configurable in TSI registers. The duration of this step changes in each
loop of a charge-transfer sequence, spreading the spectrum.
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5. Buffer Time2
Buffer time with ASW_0 and ASW_1 open, PIN0 is configured to input floating.
6. Charge transfer
ASW_0 and ASW_1 are closed and PIN0 is configured to input floating to transfer charge
from to. The transfer time should be configured (see Register Section for detail) to
ensure the full transfer after that the voltage of and will be equal.
7. Buffer Time3
Buffer time with ASW_0 and ASW_1 open, PIN0 is configured to input floating.
8. Compare
ASW_0, ASW_1 and PIN0 remain the configuration of Step7. At this step, the voltage of
sample pin PIN1 is compared to a threshold called. If voltage of PIN1 is lower than,
the sequence returns to Step2 and continues, otherwise, the sequence ends.
The voltage of sample pinis zero after initial step and increases after each charge cycle,
as shown in Figure 21-3. A larger will cause a greater increase during a cycle. The
sequence stops whenreaches. Each group has a counter which records the number
of cycles performed on it to reach. At the end of charge-transfer sequence, the group
counter is read out to estimate the, i.e. a smaller counter values indicates a larger.
Figure 21-3. Voltage of a sample pin during charge-transfer sequence
0
3.3
012345678910 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28
Cycle Number
Vth
Vs
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21.3.4. Charge transfer sequence FSM
A hardware FSM is designed in chip to perform the charge transfer sequence described in
the previous section as shown in Figure 21-4.
Figure 21-4. FSM flow of a charge-transfer sequence
Buffer Time1
Buffer Time3
Buffer Time2
Charge
Charge Transfer
Extend Charge
Compare
IDLE(discharge)
Extend Charge
enabled
Spread spectrum
disabled
Started
Vx > Vth
or the cycle number
reaches MCN
！(Vx > Vth)
or the cycle number
reaches MCN
This FSM remains in IDLE state after reset. There are 2 kinds of start condition defined by
TRGMOD bit in TSI_CTL register:
TRGMOD = 0: Software Trigger Mode. In this mode, the FSM starts after TSIS bit in TSI_CTL
register is written 1 by software.
TRGMOD = 1: Hardware Trigger Mode. In this mode the FSM starts when a falling or rising
edge on TSITG pin is detected.
Once started, the FSM runs following the flow described in Figure 21-4. The FSM leaves a
state if the duration time of this state reaches defined value, and goes into the next state.
The Extend Charge state is present only if the ECEN bit is set in TSI_CTL register. This state
is designed to implement spread spectrum function.
In comparing sate, the FSM compares voltage of the sample pin in every enabled group and
the threshold voltage. If all sample pins’ voltage reach the threshold, FSM returns IDLE state
and stops, otherwise, it returns to Buffer Time 1 state and begins the next cycle.
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As shown in Figure 21-4, after 27 cycles, (the voltage of sample pin) reaches  (the
threshold voltage).
There is also a max cycle number defined by MCN in TSI_CTL register. When the cycle
number reaches MCN, FSM returns to IDLE state and stops after Compare State, whether
 reaches or not.
21.3.5. Clock and duration time of states
There are 3 clocks in TSI module: HCLK, CTCLK and ECCLK. HCLK is system clock and
drives TSI’s register and FSM. CTCLK, which is divided from HCLK with division factor
defined by register CTCDIV is the clock used for calculating the duration time of the charge
state and Charge Transfer state. ECCLK, which is divided from HCLK with division factor
defined by register ECCDIV is the clock used to calculate the maximum duration time of
Extend Charge state.
The duration time of each state except state Extend Charge state is fixed in each loop
according to the configuration of the register.
The duration time of Buffer Time1, Buffer Time2 and Buffer Time3 are fixed to 2 HCLK periods.
The duration time of Charge state and Charge Transfer state is defined by CDT and CTDT
bits (see TSC_CTL register section for detail).
The duration time of Extend Charge state changes in each cycle of the charge-transfer FSM
and the maximum duration time are defined by ECDT[6:0] in TSI_CTL register.
The duration time of Extend Charge state in each cycle is presented in Table 21-2.
Table 21-2. Duration time of Extend Charge state in each cycle
Cycle Number
Number of ECCLKs in Extend Charge state
1
0
2
1
…
ECDT
ECDT-1
ECDT+1
ECDT
ECDT+2
ECDT+1
ECDT+3
ECDT
ECDT+4
ECDT-1
…
…
2*ECDT+1
2
2*ECDT+2
1
2*ECDT+3
0
2*ECDT+4
1
2*ECDT+5
2
…
…
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21.3.6. PIN mode control of TSI
There are 4 pins in each group and each of these pins is able to be used as a sample pin or
channel pin. Only one pin in a group should be configured as sample pin, and channel pins
can be more than one. The sample pin and channel pin(s) should not be configured as the
same pin in any case.
When a PIN is configured in GPIO (see chapter GPIO) used by TSI, the pin’s mode is
controlled by TSI. Generally, each pin has 3 modes: input, output high and output low.
The mode of a channel pin or a sample pin during a charge-transfer sequence is described
in Table 21-1 in which PIN0 represents a channel pin and PIN1 represents a sample pin, i.e.
the charge-transfer FSM take control of these channels or sample pins’ mode and the states
of related analog switches when the sequence is on-going. When the sequence is in IDLE
state, PINMOD bit in TSI_CTL register defines the mode of these pins. Pins that are
configured in GPIO used by TSI but neither sample nor channel in TSI register is called free
pins whose mode is defined by PINMOD bit in TSI_CTL, too.
21.3.7. ASW and hysteresis mode
A channel or sample pin’s analog switch is controlled by charge-transfer sequence when FSM
is running, as shown in Table 21-1. When the FSM is IDLE, these pins’ analog switches are
controlled by GxPy bits in TSI_ASW register. All free pin’s analog switches are controlled by
GxPy bits too.
TSI takes control of the analog switches when FSM is IDLE, even if these pins are not
configured to be used by TSI in GPIO. The user is able to perform user-defined charge-
transfer sequence by writing GxPy bits to control these analog switches, while controlling pin
mode directly in GPIO.
Each TSI pin’s hysteresis mode is configurable by GxPy bit in TSI_PHM register.
21.3.8. TSI operation flow
The normal operation flow of TSI is listed below:
System initialization, such as system clock configuration, TSI related GPIO configuration, etc.
Program TSI_CTL, TSI_CHCFG, TSI_INTEN, TSI_SAMPCFG and GEx bits of TSI_GCTL
register according to demand.
Enable TSI by setting TSIEN bit in TSI_CTL register.
Optional for software trigger mode: program TSIS bit to start charging transfer sequence. In
hardware trigger mode, TSI is started by falling/rising edge on the trigger pin.
Wait for the CTCF or MNERR flag in TSI_INTF and clear these flags by writing TSI_INTC.
Read out the CYCN bits in TSI_GxCYCN registers.
21.3.9. TSI flags and interrupts
Table 21-3. TSI errors and flags
Flag Name
Description
Cleared by
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CTCF
TSI stops because all enabled samplers’
sample pins reach.
CCTCF bit in TSI_INTC
MNERR
TSI stops because the cycle number
reaches the maximum value.
CMNERR bit in TSI_INTC
21.3.10. TSI GPIOs
Table 21-4. TSI pins
TSI Group
TSI Pins
GPPIN pins
TSI_GRP0
PIN0
PA0
PIN1
PA1
PIN2
PA2
PIN3
PA3
TSI_GRP1
PIN0
PA4
PIN1
PA5
PIN2
PA6
PIN3
PA7
TSI_GRP2
PIN0
PC5
PIN1
PB0
PIN2
PB1
PIN3
PB2
TSI_GRP3
PIN0
PA9
PIN1
PA10
PIN2
PA11
PIN3
PA12
TSI_GRP4
PIN0
PB3
PIN1
PB4
PIN2
PB6
PIN3
PB7
TSI_GRP5
PIN0
PB11
PIN1
PB12
PIN2
PB13
PIN3
PB14
21.4. TSI registers
21.4.1. Control register (TSI_CTL)
Address offset: 0x00
Reset value: 0x0000 0000
This register can be accessed by word(32-bit).
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31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
CDT[3:0]
CTDT[3:0]
ECDT[6:0]
ECEN
rw
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
ECDIV
CTCDIV[2:0]
Reserved
MCN[2:0]
PINMOD
EGSEL
TRGMO
D
TSIS
TSIEN
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31:28
CDT[3:0]
Charge State Duration Time
CDT[3:0] is set and clear by software. These bits controls the duration time of
Charge State in a charge-transfer sequence.
0000: 
0001: 
0010: 
….
1111:  
27:24
CTDT[3:0]
Charge Transfer State Duration Time
CTDT[3:0] is set and clear by software. These bits control the duration time of
Charge Transfer State in a charge-transfer sequence.
0000: 
0001: 
0010: 
….
1111:  
23:17
ECDT[6:0]
Extend Charge State Maximum Duration Time
ECDT[6:0] is set and clear by software. These bits control the maximum Duration
Time duration time of Extend Charge Transfer State in a charge-transfer sequence.
Extend Charge State is only present when ECEN bit in TSI_CTL register is set.
0000000: 
0000001: 
0000010: 
….
1111111:  
16
ECEN
Extend Charge State Enable.
0: Extend Charge disabled
1: Extend Charge enabled
15
ECDIV
ECCLK clock division factor.
ECCLK in TSI is divided from HCLK and ECDIV defines the division factor.
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0:   
1:   
14:12
CTCDIV[2:0]
CTCLK clock division factor.
CTCLK in TSI is divided from HCLK and CTCDIV defines the division factor.
000:   
001:   
010:   
011:   
….
111:   
11:8
Reserved
Must be kept at reset value
7:5
MCN[2:0]
Max cycle number of a sequence
MCN [2:0] defines the max cycle number of a charge-transfer sequence FSM which
stops after reaching this number.
000: 255
001: 511
010: 1023
011: 2047
100: 4095
101: 8191
110: 16383
111: Reserved
4
PINMOD
Pin mode
This bit defines a TSI pin’s mode when charge-transfer sequence is IDLE.
0: TSI pin will output low when IDLE
1: TSI pin will keep input mode when IDLE
3
EGSEL
Edge selection
This bit defines the edge type in hardware trigger mode.
0: Falling edge
1: Rising edge
2
TRGMOD
Trigger mode selection
0: Software Trigger Mode, sequence will start after TSIS bit is set.
1: Hardware Trigger Mode, sequence will start after a falling/rising edge on trigger
pin detected.
1
TSIS
TSI start
This bit is set by software to start a charge-transfer sequence in software trigger
mode and reset by hardware when the sequence stops. After setting this bit,
software can reset it to stop the started sequence manually.
0: TSI is not started
1: TSI is started.
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0
TSIEN
TSI enable
0: TSI module is enabled
1: TSI module is disabled
21.4.2. Interrupt enable register (TSI_INTEN)
Address offset: 0x04
Reset value: 0x0000 0000
This register can be accessed by word(32-bit).
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
MNERRI
E
CTCFIE
rw
rw
Bits
Fields
Descriptions
31:2
Reserved
Must be kept at reset value
1
MNERRIE
Max Cycle Number Error Interrupt Enable
0: MNERR interrupt is disabled
1: MNERR interrupt is enabled
0
CTCFIE
Charge-transfer complete flag Interrupt Enable
0: CTCF interrupt is enabled
1: CTCF interrupt is disabled
21.4.3. Interrupt flag clear register (TSI_INTC)
Address offset: 0x08
Reset value: 0x0000 0000
This register can be accessed by word(32-bit).
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
CMNER
R
CCTCF
w
w
Bits
Fields
Descriptions
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31:2
Reserved
Must be kept at reset value
1
CMNERR
Clear max cycle number error
0: Reserved
1: Clear MNERR
0
CCTCF
Clear charge-transfer complete flag
0: Reserved
1: Clear CTCF
21.4.4. Interrupt flag register (TSI_INTF)
Address offset: 0x0C
Reset value: 0x0000 0000
This register can be accessed by word(32-bit).
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
MNERR
CTCF
r
r
Bits
Fields
Descriptions
31:2
Reserved
Must be kept at reset value
1
MNERR
Max Cycle Number Error
This bit is set by hardware after charge-transfer sequence stops because it
reaches the max cycle number defined by MCN[2:0]. This bit is cleared by writing 1
to CMNERR bit in TSI_INTC register.
0: No Max Count Error
1: Max Count Error
0
CTCF
Charge-Transfer complete flag
This bit is set by hardware after charge-transfer sequence stops because all
enabled group’s sample pins reach the threshold voltage or because the cycle
number reaches the value defined by MCN[2:0]. This bit is cleared by writing 1 to
CCTCF bit in TSI_INTC register.
0: Charge-Transfer not complete
1: Charge-Transfer complete
21.4.5. Pin hysteresis mode register (TSI_PHM)
Address offset: 0x10
Reset value: 0x0000 0000
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This register can be accessed by word(32-bit).
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
G5P3
G5P2
G5P1
G5P0
G4P3
G4P2
G4P1
G4P0
rw
rw
rw
rw
rw
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
G3P3
G3P2
G3P1
G3P0
G2P3
G2P2
G2P1
G2P0
G1P3
G1P2
G1P1
G1P0
G0P3
G0P2
G0P1
G0P0
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31:24
Reserved
Must be kept at reset value
23:0
GxPy
Pin hysteresis mode
This bit is set and cleared by software.
0: Pin GxPy Schmitt trigger hysteresis mode disabled
1: Pin GxPy Schmitt trigger hysteresis mode enabled
21.4.6. Analog switch register (TSI_ASW)
Address offset: 0x18
Reset value: 0x0000 0000
This register can be accessed by word(32-bit).
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
G5P3
G5P2
G5P1
G5P0
G4P3
G4P2
G4P1
G4P0
rw
rw
rw
rw
rw
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
G3P3
G3P2
G3P1
G3P0
G2P3
G2P2
G2P1
G2P0
G1P3
G1P2
G1P1
G1P0
G0P3
G0P2
G0P1
G0P0
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31:24
Reserved
Must be kept at reset value
23:0
GxPy
Analog switch state.
This bit is set and cleared by software.
0: Analog switch of GxPy is open
1: Analog switch of GxPy is closed
21.4.7. Sample configuration register (TSI_SAMPCFG)
Address offset: 0x20
Reset value: 0x0000 0000
This register can be accessed by word(32-bit).
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31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
G5P3
G5P2
G5P1
G5P0
G4P3
G4P2
G4P1
G4P0
rw
rw
rw
rw
rw
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
G3P3
G3P2
G3P1
G3P0
G2P3
G2P2
G2P1
G2P0
G1P3
G1P2
G1P1
G1P0
G0P3
G0P2
G0P1
G0P0
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31:24
Reserved
Must be kept at reset value
23:0
GxPy
Sample pin mode
This bit is set and cleared by software.
0: Pin GxPy is not a sample pin
1: Pin GxPy is a sample pin
21.4.8. Channel configuration register (TSI_CHCFG)
Address offset: 0x28
Reset value: 0x0000 0000
This register can be accessed by word(32-bit).
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
G5P3
G5P2
G5P1
G5P0
G4P3
G4P2
G4P1
G4P0
rw
rw
rw
rw
rw
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
G3P3
G3P2
G3P1
G3P0
G2P3
G2P2
G2P1
G2P0
G1P3
G1P2
G1P1
G1P0
G0P3
G0P2
G0P1
G0P0
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31:24
Reserved
Must be kept at reset value
23:0
GxPy
Channel pin mode
This bit is set and cleared by software.
0: Pin GxPy is not a channel pin
1: Pin GxPy is a channel pin
21.4.9. Group control register (TSI_GCTL)
Address offset: 0x30
Reset value: 0x0000 0000
This register can be accessed by word(32-bit).
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31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
GC5
GC4
GC3
GC2
GC1
GC0
r
r
r
r
r
r
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
GE5
GE4
GE3
GE2
GE1
GE0
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31:24
Reserved
Must be kept at reset value
21:16
GCx
Group complete
This bit is set by hardware when charge-transfer sequence for an enabled group is
complete. It is cleared by hardware when a new charge-transfer sequence starts.
0: Charge-transfer for group x is not complete
1: Charge-transfer for group x is complete
15:6
Reserved
Must be kept at reset value
5:0
GEx
Group enable
This bit is set and cleared by software.
0: Group x is disabled
1: Group x is enabled
21.4.10. Group x cycle number registers (TSI_GxCYCN) (x= 0..5)
Address offset: 0x30 + 0x04 *(x + 1)
Reset value: 0x0000 0000
This register can be accessed by word(32-bit).
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
CYCN[13:0]
rw
Bits
Fields
Descriptions
31:14
Reserved
Must be kept at reset value
13:0
CYCN[13:0]
Cycle number
These bits reflect the cycle number for a group as soon as a charge-transfer
sequence completes. They are cleared by hardware when a new charge-transfer
sequence starts.
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22. HDMI-CEC controller(HDMI-CEC)
22.1. Introduction
Consumer Electronics Control (CEC) belongs to a part of HDMI (High-Definition Multimedia
Interface) standard. CEC, as a kind of protocol, it provides the advanced control functions of
all kinds of audio-visual products in a user environment. The CEC protocol gets hardware
support from the HDMI-CEC controller.
22.2. Main features
HDMI-CEC controller complies with HDMI-CEC v1.4 Specification
Tow clock source options for 32.768KHz CEC clock:
1) LXTAL oscillator
2) IRC8M oscillator with settled prescaler (IRC8M/244)
For ultra low-power applications ,HDMI-CEC controller can work in Deep-sleep mode
Programmable SFT(Signal Free Time) value for arbitration priority:
1) User configure
2) Auto configure by controller as HDMI-CEC protocol specification
Programmable own address(OADR)
Listen mode supports user receiving messages on the CEC line but not disturb the CEC
line.
RX bit-tolerance function support for higher compatibility
Bit Error Detection
1) Short bit period error(RSBPE)
2) Long bit period error(RLBPE)
3) Bit rising error(RBRE)
Programmable error-bit generation
1) RSBPE detection will always generate error-bit
2) RLBPE detection will generate error-bit if RLBPEGEN=1
3) RBRE detection will generate error-bit if RBREGEN=1
Transmission error detection (TERR)
Transmission underrun detection (TU)
Reception overrun detection (RO)
Arbitration lost detection (LSTARB),if asserted controller will automatic retry transmission
22.3. Function description
22.3.1. CEC bus pin
The CEC device only use one bidirectional line to connect to others. The CEC pin through a
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27KΩ pull-up resister connected to a +3.3V supply voltage. When the CEC device is in the
output state, in order to allow a wired-and connection it must have an open-drain or open-
collector.
Using HDMI-CEC controller needs configuring CEC pin as alternate function open drain and
a 27kΩ resister is also needed for pulling-up the CEC pin.
Figure 22-1. HDMI-CEC Controller Block Diagram
ARM
Cortex-M3 AHB to APB
Bridge
RCU
APB Bus
CEC Clock
IRC8M/244
LXTAL
Interrupt/Wake
HDMI-CEC
Controller
HDMI-CEC
Interface and
Registers
HDMI-CEC
Core
3.3V 27KΩ
CEC Bus line
CEC
Device 1 CEC
Device 2
CEC PAD
MCU
22.3.2. Message description
A complete message includes one or more frames and the message structure is shown as
below:
Bus
High
START
Bit
Header
Frame
Data
Frame
. . . .
Data
Frame
Data
Frame
Bus
High
The frame has two types:
1) Header frame: The first frame in the message which followed the start-bit, it consists of
the source logical address field and the destination logical address field.
2) Data frame: All frames in the message except header frame. All frames are ten bits long
and have the same basic structure as shown below:
Frame Structure
7
6
5
4
3
2
1
0
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Information bits
ENDOM
ACK
The information bits are data, opcodes or addresses, dependent on context. The control bits,
ENDOM and ACK, are always present and always have the same usage.
22.3.3. Bit timing description
All bits timing in the message are divided into two types: Start bit and Data bit.
1) Start Bit: The start bit has to be validated by its low duration(a) and its total duration(b)
showed as below:
High Impedence
Low Impedence
a
b
0ms 3.7m
s4.5m
s
3.5ms 3.9ms 4.3ms 4.7ms
Start Bit Timing
2) Data Bit: The valid data bit timing is constrained as below:
High Impedence
Low Impedence
Ts
Data Bit Timing
Logic 0
Logic 1
1.5ms 2.4ms
T1
0.6ms
T2 T5
T3 T4 T6 T7 T8
Safe
Sample
Period
Nominal sample time 1.05 ms
2.4ms
High Impedence
Low Impedence
Table 22-1. Data Bit Timing Parameter Table
Ts
Time (ms)
The bit start event.
T1
0.4ms
When indicating a logical 1,T1 as the earliest time for a low - high
transition.
T2
0.8ms
When indicating a logical 1,T2 as the latest time for a low - high
transition.
T3
0.85ms
The earliest time it is safe to sample the signal line to determine
its state.
T4
1.25ms
The latest time it is safe to sample the signal line to determine
its state.
T5
1.3ms
T5 as the earliest time that a device is allowed to return to a high
impedance state(logical 0).
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Ts
Time (ms)
The bit start event.
T6
1.7ms
T6 as the latest time that a device is allowed to return to a high
impedance state(logical 0).
T7
2.05ms
T7 as the earliest time for the start of a following bit.
2.4ms
As a nominal data bit period.
T8
2.75ms
T8 as the latest time for the start of a following bit.
22.3.4. Arbitration
CEC line arbitration starts from the front edge of the start bit to the end of the Initiator address
bits among the Header Block. In the meantime the Initiator should monitors the CEC
line.During this period , if low impedance be detected when whilst in high impedance state
then it should assume that it has lost the arbitration to a second Initiator.
|Arbitration Phase|
Bus
High
START
Bit
END
OM
ACK
Bus
High
Before attempting to transmit or re-transmit a frame, a device shall ensure that the CEC line
has been inactive for a number of bit periods.
This signal free time is defined as the time since the start of the final bit of the previous frame.
SFT of three nominal bit period
ACK bit of last frame of
previous message
Start bit of next
message
The length of the required signal free time depends on the current status of the control signal
line and the initiating device. If SFT=0x0, the HDMI-CEC controller’s SFT will perform as table
below:
Precondition
Signal Free Time (nominal data
bit periods)
Present Initiator wants to send another message
immediately after its previous message
≥7
New Initiator wants to send a message
≥5
Previous attempt to send message unsuccessful
≥3
This means that there is an opportunity for other devices to gain access to the CEC line during
INITIATOR[7:4]
DESTINATION[3:0]
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the periods mentioned above to send their own messages after the current device has
finished sending its current message.
If SFT is not 0x0,the corresponding user configure SFT will be performed.
22.3.5. SFT option bit description
SFT option bit support another way for saving bus inactive time through setting more SFT
counter’s start time point.
When SFTOPT = 0, the SFT timer will start at the time SOM bit asserted when the controller
is in the idle state.
When SFTOPT = 1, the SFT timer will start at the time CEC bus is in idle state and the SFT
time will be saved if you configure the SOM after SFT done because the controller will start
transmit without any latency.
When SFTOPT = 1, some other cases will also start the SFT counter:
In case of regular TX/RX complete(TEND/REND asserted)
In case of transmission not complete such as the time TERR,TAERR or TU asserted.
In case of receiving progress, if some error detected and error bit is generated, the SFT
timer will start when output error bit finished.
22.3.6. Error definition
Error-Bit
If some errors are occurred and corresponding generation configure is enabled the HDMI-
CEC controller will generate an error bit on the CEC pin for indicating. Error bit period
definition is shown as below:
Error-Bit Timing
High
impedence
Low
impedence
3.6ms +/-
0.24ms
Frame error
CEC protocol defines that each frame of message need the acknowledgement to confirm the
communication is successful. For broadcast(destination address=0xF), the ACK bit should be
logic 1 and for singlecast(destination address<0xF), the ACK bit should be logic 0,otherwise
the frame error occurs(TAERR/RAE flag asserted).
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Another frame error situation is that the CEC bus pin voltage is different from CEC pad when
HDMI-CEC controller is under initiator state(TERR flag asserted).
Bit rising error(RBRE)
RBRE flag can be asserted if rising edge detected during the RBRE checking window and
RBRE flag will also generate CEC interrupt if the RBREIE=1.
If RBRESTP=1,the controller will stop receiving message and if RBREGEN=1 the error-bit
will be generated.
If RBRESTP=1 in broadcast the RBRE flag asserted, the error bit will be generated to notify
the initiator the error.If you do not want to generate the error bit for RBRE detection you can
configure the RBREGEN=0 and BCNG=1.
Note: The RBRESTP=0 and RBREGEN=1 configuration must be avoided.
Short bit period error(RSBPE)
RSBPE is set when the period of the neighboring falling edge is shorter than expected.
RSBPE flag will also generate CEC interrupt if the RSBPEIE=1.
If the RSBPE flag asserted, the error bit will must be generated except one of the cases below:
1) BCNG = 1
2) LMEN = 1
3) Receiving broadcast
Long bit period error(RLBPE)
RLBPE is set when the period of the neighboring falling edge is longer than expected. RLBPE
flag will also generate CEC interrupt if the RLBPEIE=1.
When RLBPE asserted, controller will stop receiving message and generate error bit if in one
of the cases below:
1) RLBPEGEN=1 in both singlecast and broadcast
2) BCNG=0 in broadcast
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High
Impedence
Low Impedence
Ts
Logic
0
Logic
1
1.5ms 2.4ms
T1
0.6ms
T2 T5
T3 T4 T6 T7 T8
2.4ms
Legend: Checking Window
BRE BRE
SBPE
Nominal sample time 1.05 ms
LBPE
High
Impedence
Low Impedence
Table 22-2. Error Handling Timing Parameter Table
Symbol
RTOL
Time(ms)
Description
Ts
-
0ms
The bit start event.
T1
1
0.3ms
When indicating a logical 1,T1 as the earliest time for a low -
high transition.
0
0.4ms
T2
0
0.8ms
When indicating a logical 1,T2 as the latest time for a low -
high transition.
1
0.9ms
T3
-
0.85ms
The earliest time it is safe to sample the signal line to
determine its state.
T4
-
1.25ms
The latest time it is safe to sample the signal line to determine
its state.
T5
1
1.2ms
T5 as the earliest time that a device is allowed to return to a
high impedance state(logical 0).
0
1.3ms
T6
0
1.7ms
T6 as the latest time that a device is allowed to return to a high
impedance state(logical 0).
1
1.8ms
T7
1
1.85ms
T7 as the earliest time for the start of a following bit.
0
2.05ms
2.4ms
As a nominal data bit period.
T8
0
2.75ms
T8 as the latest time for the start of a following bit.
1
2.95ms
Transmission error detection(TERR)
The TERR is set when the initiator find low impedance on the CEC bus when it is transmitting
high impedance. TERR will also generate CEC interrupt if TERRIE=1.
When TERR asserted the transmission is aborted and the software can retry the transmission.
TERR check window is depending on the different bit state of the frame shown as below:
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High
Impedence
Low Impedence
Ts
Logic
0
Logic
1
1.5ms 2.4ms
T1
0.6ms
T2 T5
T3 T4 T6 T7 T8
2.4ms
Legend: Checking
Window TX data=0
Nominal sample time 1.05 ms
TX arb-bit=0/1
TX data=1
TX ack
High
Impedence
Low Impedence
Table 22-3. TERR Timing Parameter Table
Symbol
RTOL
Time(ms)
Description
Ts
-
0ms
The bit start event.
T1
1
0.3ms
The earliest time for a low - high transition when indicating a
logical 1.
0
0.4ms
T2
0
0.8ms
The latest time for a low - high transition when indicating a
logical 1.
1
0.9ms
T3
-
0.85ms
The earliest time it is safe to sample the signal line to
determine its state.
T4
-
1.25ms
The latest time it is safe to sample the signal line to determine
its state.
T5
1
1.2ms
The earliest time a device is permitted return to a high
impedance state (logical 0).
0
1.3ms
T6
0
1.7ms
The latest time a device is permitted return to a high
impedance state (logical 0).
1
1.8ms
T7
1
1.85ms
The earliest time for the start of a following bit.
0
2.05ms
2.4ms
The nominal data bit period.
T8
0
2.75ms
The latest time for the start of a following bit.
1
2.95ms
22.3.7. HDMI-CEC interrupt
There 13 interrupts in HDMI-CEC controller and each are made up of corresponding flag and
interrupt enable bit:
No.
Interrupt event in HDMI-CEC
Event flag
Interrupt enable bit
1
Arbitration lost
LSTARB
LSTARBIE
2
TX Byte Request
TBR
TBRIE
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No.
Interrupt event in HDMI-CEC
Event flag
Interrupt enable bit
3
Transmission end
TEND
TENDIE
4
TX Byte buffer underrun
TU
TUIE
5
TX error
TERR
TERRIE
6
TX acknowledge error
TAERR
TAERRIE
7
RX Byte Received
RBR
RBRIE
8
Reception end
REND
RENDIE
9
RX Overrun
RO
ROIE
10
RX-Bit rising error
RBRE
BREIE
11
RX-Short Bit Period Error
RSBPE
RSBPEIE
12
RX-Long Bit Period Error
RLBPE
RLBPEIE
13
RX acknowledge error
RAE
RAEIE
Note: Any HDMI-CEC interrupt will wake up the chip from Deep-sleep Mode.
22.4. HDMI-CEC registers
22.4.1. Control register (CEC_CTL)
Address offset: 0x00
Reset value: 0x0000 0000
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
ENDOM
SOM
CECEN
rs
rs
rw
Bits
Fields
Descriptions
31:3
Reserved
Must be kept at reset value
2
ENDOM
ENDOM bit value in the next frame in TX mode.
ENDOM can only be software wrote when CECON=1.ENDOM is cleared by
hardware in the same situation of clear SOM.
0: Next frame send 0 in ENDOM bit position
1: Next frame send 1 in ENDOM bit position
1
SOM
Start of sending a message.
SOM can only be software wrote when CECON=1.SOM is cleared by hardware if
any of flags asserted: TEND, TU, TAERR, TERR and CECON=0.
If the message consists of only one frame, ENDOM should be set before
configuring txdata. After setting SOM, the SFT counter will start and when SFT is
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done the Start-bit will performance one CEC line. Software can abort sending the
message through clear CECON bit under SOM=1.
0: No CEC transmission is on-going
1: CEC transmission is pending or executing
0
CECEN
Enable/disable HDMI-CEC controller bit.
CECON bit is configured by software.
0: Disable HDMI-CEC controller. Abort any sending message state and clear
ENDOM/SOM
1: Enable CEC controller and go into receiving state if SOM=0
22.4.2. Configuration register (CEC_CFG)
Address offset: 0x04
Reset value: 0x0000 0000
This register has to be accessed by word(32-bit)
Note: This register can only be write when CECON=0
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
LMEN
OADR [14:0]
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
SFTOPT
BCNG
RLBPEGEN
RBREGEN
RBRESTP
RTOL
SFT[2:0]
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31
LMEN
Listen Mode Enable Bit
This bit is set and cleared by software.
0: Only receive broadcast and singlecast in OADR address with appropriate ACK
1: Receive broadcast and singlecast in OADR address with appropriate ACK and
receive message whose destination address is not in OADR without feedback ACK
30:16
OADR[14:0]
Own Address
Each bit of OADR represents one destination address. For example: if oar[0]=1,the
controller will receive the message sent address=0x0.This means the controller can
be configured to multiple own address. Broadcast message is always received.
After received destination address(last 4 bit of HEADER frame), if it is valid in the oar,
the controller will feedback with positive acknowledge ,if it is not valid in the oar and
LMEN=1,the controller will receive the message with no acknowledge, if it is not valid
in the oar and LMEN=0,the controller will not receive the message.
15:9
Reserved
Must be kept at reset value
8
SFTOPT
The SFT start option bit
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This bit is set and cleared by software.
0: SFT counter starts counting when SOM is asserted
1: SFT counter starts automatically after transmission/reception en
7
BCNG
Do not generate Error-bit in broadcast message
This bit is set and cleared by software.
0: In broadcast mode, RBRE and RLBPE will generate Error-bit on CEC line and if
LMEN=1, RSBPE will also generate Error-bit
1: Error-bit is not generated in the same condition as above
6
RLBPEGEN
Generate Error-bit when detected RLBPE in singlecast
This bit is set and cleared by software.
0: Not generate Error-bit on CEC line when detected RLBPE in singlecast
1: Generate Error-bit on CEC line when detected RLBPE in singlecast
5
RBREGEN
Generate Error-bit when detected RBRE in singlecast
This bit is set and cleared by software.
0: Not generate Error-bit on CEC line when detected RBRE in singlecast
1: Generate Error-bit on CEC line when detected RBRE in singlecast
4
RBRESTP
Whether stop receive message when detected RBRE
This bit is set and cleared by software.
0: Do not stop reception for RBRE and data bit is sampled at nominal time(1.05ms)
1: Stop reception for RBRE
3
RTOL
Reception bit timing tolerance
This bit is set and cleared by software.
0: Standard bit timing tolerance
1: Extended bit timing tolerance
2:0
SFT[2:0]
Signal Free Time
This bit is set and cleared by software.
If SFT=0x0, the SFT time will perform as HDMI-CEC protocol description and if not,
the SFT time is fixed configured by software. The start point is the falling edge of the
ACK bit.
0x0:
- 3 Standard data-bit period if SFT counter is start because of unsuccessful
transmission(LSTARB=1,TERR=1,TU=1 or TAERR=1)
- 5 Standard data-bit period if CEC controller is the new initiator
- 7 Standard data-bit period if CEC controller has successful completed
transmission
0x1: 1.5 nominal data bit periods
0x2: 2.5 nominal data bit periods
0x3: 3.5 nominal data bit periods
0x4: 4.5 nominal data bit periods
0x5: 5.5 nominal data bit periods
0x6: 6.5 nominal data bit periods
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0x7: 7.5 nominal data bit periods
22.4.3. Transmit data register (CEC_TDATA)
Address offset: 0x08
Reset value: 0x0000 0000
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
TXDATA[7:0]
w
Bits
Fields
Descriptions
31:8
Reserved
Must be kept at reset value
7:0
TXDATA[7:0]
Tx data register
This bit is write only.
22.4.4. Receive data register (CEC_RDATA)
Address offset: 0xC
Reset value: 0x0000 0000
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
RXDATA[7:0]
r
Bits
Fields
Descriptions
31:8
Reserved
Must be kept at reset value
7:0
RXDATA[7:0]
Rx data register
This bit is read only and contains the last data byte which has been received from
the CEC line.
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22.4.5. Interrupt Flag Register (CEC_INTF)
Address offset: 0x10
Reset value: 0x0000 0000
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
TAERR
TERR
TU
TEND
TBR
LSTARB
RAE
RLBPE
RSBPE
RBRE
RO
REND
RBR
rc_w1
rc_w1
rc_w1
rc_w1
rc_w1
rc_w1
rc_w1
rc_w1
rc_w1
rc_w1
rc_w1
rc_w1
rc_w1
Bits
Fields
Descriptions
31:13
Reserved
Must be kept at reset value
12
TAERR
Tx ACK Error flag.
This bit is set by hardware and cleared by software write at 1.
The ACK bit is received 1 in singlecast and is received 0 in broadcast will assert
the flag. TAERR will stop sending message and clear SOM and ENDOM.
11
TERR
Tx-Error
This bit is set by hardware and cleared by software write at 1.
TERR is asserted if the controller is in initiator state and find the CEC line is low
impedance but it does not pull it down. TERR will stop sending message and
clear SOM and ENDOM.
10
TU
Tx data buffer underrun
This bit is set by hardware and cleared by software write at 1.
TU is asserted if the software does not write data before sending the next byte.
TU will stop sending message and clear SOM and ENDOM.
9
TEND
Transmission successfully end
This bit is set by hardware and cleared by software write at 1.
TEND is asserted if the all frames of the message are successfully transmitted.
TEND will clear SOM and ENDOM bit.
8
TBR
Tx-Byte data request
This bit is set by hardware and cleared by software write at 1.
TBR is asserted when the 4th bit of current frame is transmitted and software
should write data into txdata within 6 nominal data-bit periods
7
LSTARB
Arbitration lost
This bit is set by hardware and cleared by software write at 1.
LSTARB is asserted when either situation is occurs: external CEC device pull
down the CEC line for sending start bit when controller is in SFT state or the
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controller and CEC device sending the start bit at the same time but the
controller’s initiator address priority is lower.
If LSTARB is asserted, the controller will get into reception state and after finish
receiving the message the controller will retry to send message. During
receiving and sending message, the SOM will keep set.
6
RAE
Rx ACK Error
This bit is set by hardware and cleared by software write at 1.
RAE is asserted if ACK=0 in broadcast or ACK=1 in singlecast under LMEN=1
and destination address is not in OADR.
RAE will stop receiving message.
5
RLBPE
Long Bit Period Error
This bit is set by hardware and cleared by software write at 1.
RLBPE is asserted when the data-bit is out of the maximum period. RLBPE will
stop receiving message and generate error-bit if RLBPEGEN=1 in singlecast or
BCNG=0 in broadcast.
4
RSBPE
Short Bit Period Error
This bit is set by hardware and cleared by software write at 1.
RSBPE is asserted if a data-bit period is less than the minimal period.
3
RBRE
Bit Rising Error
This bit is set by hardware and cleared by software write at 1.
RBRE is asserted if the rising edge in a period is occurs in unexpected time.
2
RO
RX Overrun
This bit is set by hardware and cleared by software write at 1.
RO is asserted when a new byte is received and RBR is also set.
RO will stop receiving message and send an incorrect ACK bit.
1
REND
End of Reception
This bit is set by hardware and cleared by software write at 1.
REND is asserted if the controller received the whole message with feedback
correct ACK. REND is asserted at the same time of RBR.
0
RBR
Rx-Byte data received
This bit is set by hardware and cleared by software write at 1.
RBR is asserted if the controller received the whole message with feedback
correct ACK. When RBR is asserted, the rxdata is valid.
22.4.6. Interrupt enable register (CEC_INTEN)
Address offset: 0x14
Reset value: 0x0000 0000
This register has to be accessed by word (32-bit)
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31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
TAERRIE
TERRIE
TUIE
TXENDIE
TBRIE
LSTARBI
E
RAEIE
RLBPEIE
RSBPEIE
RBREIE
ROIE
RENDIE
RBRIE
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31:13
Reserved
Must be kept at reset value
12
TAERRIE
TAERR Interrupt Enable.
This bit is set by and cleared by software.
0: TAERR interrupt disable
1: TAERR interrupt enable
11
TERRIE
TERR Interrupt Enable.
This bit is set by and cleared by software.
0: TERR interrupt disable
1: TERR interrupt enable
10
TUIE
TU Interrupt Enable.
This bit is set by and cleared by software.
0: TU interrupt disable
1: TU interrupt enable
9
TENDIE
TEND Interrupt Enable.
This bit is set by and cleared by software.
0: TEND interrupt disable
1: TEND interrupt enable
8
TBRIE
TBR Interrupt Enable.
This bit is set by and cleared by software.
0: TBR interrupt disable
1: TBR interrupt enable
7
LSTARBIE
ALRLST Interrupt Enable.
This bit is set by and cleared by software.
0: LSTARB interrupt disable
1: LSTARB interrupt enable
6
RAEIE
RAE Interrupt Enable.
This bit is set by and cleared by software.
0: RAE interrupt disable
1: RAE interrupt enable
5
RLBPEIE
RLBPE Interrupt Enable.
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This bit is set by and cleared by software.
0: RLBPE interrupt disable
1: RLBPE interrupt enable
4
RSBPEIE
RSBPE Interrupt Enable.
This bit is set by and cleared by software.
0: RSBPE interrupt disable
1: RSBPE interrupt enable
3
RBREIE
RBRE Interrupt Enable.
This bit is set by and cleared by software.
0: RBRE interrupt disable
1: RBRE interrupt enable
2
ROIE
RO Interrupt Enable.
This bit is set by and cleared by software.
0: RO interrupt disable
1: RO interrupt enable
1
RENDIE
REND Interrupt Enable.
This bit is set by and cleared by software.
0: REND interrupt disable
1: REND interrupt enable
0
RBRIE
RBR Interrupt Enable.
This bit is set by and cleared by software.
0: RBR interrupt disable
1: RBR interrupt enable
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23. Segment LCD controller (SLCD)
This chapter applies to GD32F170xx and GD32F190xx devices.
23.1. Introduction
The SLCD controller directly drives LCD displays by creating the AC segment and common
voltage signals automatically. It can drive the monochrome passive liquid crystal display (LCD)
which composed of a plurality of segments (pixels or complete symbols) that can be converted
to visible or invisible. The SLCD controller can support up to 32 segments and 8 commons.
23.2. Main features
Configurable frame frequency
Blinking of individual segments or all segments
Supports Static, 1/2, 1/3, 1/4, 1/6 and 1/8 duty
Supports 1/2, 1/3 and 1/4 bias
Double buffer up to 8x32 bits registers to store SLCD_DATAx
The contrast can also be adjusted by configuring dead time
VSLCD rails decoupling capability
23.3. Function description
23.3.1. SLCD Architecture
The block diagram of the SLCD controller is shown as follows.
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Figure 23-1. SLCD Block Diagram
SLCD
SEG
COM
Driver
Clock
generator
SLCD
RAM
Blink
control
ANALOG
matrix
SLCD
REG
COM0...7
SEG0...31
data data
control signal
The SLCD REG is the register of SLCD controller, which configured by APB bus, and
generate interrupt to CPU. It includes SLCD_CTL, SLCD_CFG, SLCD_STAT, SLCD_STATC,
SLCD_DATAx registers.
The Clock generator generates SLCD clock from input clock. The SLCD clock drivers the
blink control and SEG/COM driver. The Blink control generates blink frequency and blink
pixels. The SEG/COM driver generates segment and common signals to ANALOG matrix.
The ANALOG matrix implements segment and common voltages.
23.3.2. Clock generator
SLCD input clock is the same as RTCCLK, 3 different clock sources: LXTAL, IRC40K and
HXTAL divided by 32 can be selected by RTCSRC bits in RCU_BDCTL register. The input
clock frequency varies from 32KHz to 1MHz.
The SLCD controller uses the input clock signal from the integrated clock divider to generate
the timing for common and segment lines. The SLCD clock frequency is selected with the
PSC and DIV bits in SLCD_CTL registers. The resulting SLCD clock frequency is calculated
by:
 
  
The SLCD clock is the time base for the SLCD controller. The frequency of SLCD clock is
equivalent to the phase frequency. One SLCD frame is one odd frame or one even frame,
both of them have several phases as many as active common terminals. The duty is the
Number defined as 1/ (the number of common terminals on a given SLCD display). So the
frame frequency is calculated by:
  
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The SOF bit in SLCD_STAT register is set by the hardware at the start of the frame, and the
SLCD interrupt is executed if the SOFIE bit in SLCD_CFG is set. SOF is cleared by writing 1
to the SOFC bit in SLCD_STATC register.
Figure 23-2. 1/3 Bias, 1/4 Duty
COM
SEG
VSLCD
2/3VSLCD
1/3VSLCD
VSS
VSLCD
2/3VSLCD
1/3VSLCD
VSS
COM inact.
SEG inact.
COM inact. COM act. COM inact.
Odd frame Even frame
SEG act. SEG inact. SEG act.
Phase 0 Phase 1 Phase 2 Phase 0Phase 3
COM inact.COM inact. COM act. COM inact.
SEG inact. SEG act. SEG inact. SEG act.
Phase 1 Phase 2 Phase 3
23.3.3. Blink control
The SLCD controller also supports blinking. The blinking mode controlled by BLKMOD bits in
SLCD_CFG register. BLKMOD = 01 allows to blink individual segment on SEG0 with COM0,
with BLKMOD = 10 all commons on SEG0 are blinking, with BLKMOD = 11 all segments with
all commons are blinking, and with BLKMOD = 00 blinking is disabled.
The blink frequency is generated from SLCD clock and selected with BLKDIV bit in
SLCD_CFG registers. The resulting BLINK frequency is calculated by:
 

After a blinking mode (BLKMOD = 01, 10 or 11) is selected, the enabled segments or all
segments go blank at the next frame boundary and stay off for half a BLKCLK period. Then
they go active at the next frame boundary and stay on for another half BLKCLK period before
they go blank again at a frame boundary.
23.3.4. SEG/COM Driver
SEG/COM Driver generates segments and commons signals.
BIAS generator:
The bias is selected by setting BIAS bits in SLCD_CTL registers. It has its max amplitude
VSLCD or VSS only in the corresponding phase of a frame cycle. The odd frame voltage and
even frame voltage are shown as follows:
Table 23-1. The odd frame voltage
BIAS
Static
1/2 bias
1/3 bias
1/4 bias
COM active
VSLCD
VSLCD
VSLCD
VSLCD
GD32F1x0 User Manual
615
BIAS
Static
1/2 bias
1/3 bias
1/4 bias
COM inactive
/
1/2 VSLCD
1/3 VSLCD
1/4 VSLCD
SEG active
VSS
VSS
VSS
VSS
SEG inactive
VSLCD
VSLCD
2/3 VSLCD
1/2 VSLCD
Table 23-2. The even frame voltage
BIAS
Static
1/2 bias
1/3 bias
1/4 bias
COM active
VSS
VSS
VSS
VSS
COM inactive
/
1/2 VSLCD
2/3 VSLCD
3/4 VSLCD
SEG active
VSLCD
VSLCD
VSLCD
VSLCD
SEG inactive
VSS
VSS
1/3 VSLCD
1/2 VSLCD
COM signal:
The common signal is selected by DUTY bits in SLCD_CTL register. When DUTY is 000,
static duty selected. Only COM[0] used and only one phase in odd frame or even frame, so
COM[0] driver active signal always. When DUTY is 001, only COM[1:0] and 2 phases used.
When DUTY is 010, only COM[2:0] and 3 phases used. When DUTY is 011, only COM[3:0]
and 4 phases used. When DUTY is 100, COM[7:0] and 8 phases used. When DUTY is 101,
COM[5:0] and 6 phases used. The all common signal driver is shown as follows:
Table 23-3. The all common signal driver
phase
1
2
3
4
5
6
7
8
COM0
active
inactive
inactive
inactive
inactive
inactive
inactive
inactive
COM1
inactive
active
inactive
inactive
inactive
inactive
inactive
inactive
COM2
inactive
inactive
active
inactive
inactive
inactive
inactive
inactive
COM3
inactive
inactive
inactive
active
inactive
inactive
inactive
inactive
COM4
inactive
inactive
inactive
inactive
active
inactive
inactive
inactive
COM5
inactive
inactive
inactive
inactive
inactive
active
inactive
inactive
COM6
inactive
inactive
inactive
inactive
inactive
inactive
active
inactive
COM7
inactive
inactive
inactive
inactive
inactive
inactive
inactive
active
SEG signal:
The segment signals are read from SLCD_DATAx registers. The segment signals data are
SLCD_DATAx when phase x. When the value is 1, the corresponding segment drives active
signal. When the value is 0, the corresponding segment drives inactive signal.
For example, if the application need to active the pixel COM2 SEG2, COM3 SEG2, and COM5
SEG4. It should set the bit2 in the SLCD_DATA2, the bit2 in the SLCD_DATA3, and the bit4
in the SLCD_DATA5. Then the SEG2 signal will active at the third and fourth phase of each
odd and even frame, the SEG4 signal will active at the sixth phase of each odd and even
frame. The active and inactive voltages are shown in Table 23-1 and Table 23-2. The segment
signals show in figure 23-3 is the result to the above configuration when bias is 1/4 and duty
is 1/6.
GD32F1x0 User Manual
616
Figure 23-3. 1/4 Bias, 1/6 Duty
COM0
COM2
COM3
COM5
SEG2
SEG4
VSLCD
3/4VSLCD
1/2VSLCD
1/4VSLCD
VSS
VSLCD
3/4VSLCD
1/2VSLCD
1/4VSLCD
VSS
VSLCD
3/4VSLCD
1/2VSLCD
1/4VSLCD
VSS
VSLCD
3/4VSLCD
1/2VSLCD
1/4VSLCD
VSS
VSLCD
3/4VSLCD
1/2VSLCD
1/4VSLCD
VSS
VSLCD
3/4VSLCD
1/2VSLCD
1/4VSLCD
VSS
DEAD time:
The dead time is using DTD bits in SLCD_CFG register. It inserts VSS after each even frame.
The number of phase inserted is defined by DTD bits. The application can adjust the contrast
according to the configuration of dead time.
Figure 23-4. SLCD dead time (1/3 Bias, 1/4 Duty)
Odd frame Even frame Dead time Odd frame Even frame
COM
SEG
GD32F1x0 User Manual
617
23.3.5. Double buffer memory
The double buffer memory is used to ensure the coherency of the displayed information.
The application access the first buffer according to modify the SLCD_DATAx registers. After
writing the displayed information into the SLCD_DATAx registers, the application need to set
the UPRF bit in SLCD_STAT register, then the hardware will transfer the data from the first
buffer to the seconed buffer, during this time, the UPRF keeps set and the SLCD_DATAx
registers are write protected. When the transfer is completed, the UPRF is cleared and the
UPDF is set by the hardware, an interrupt will be generated if the UPDIE is set. The segment
signal is driven by the data in the second buffer, so the displayed information will not be
influenced by writing SLCD_DATAx.
If the UPRF is set when the display is disabled (SLCDON = 0), the transfer will not occur until
the SLCDON is set.
23.3.6. ANALOG matrix
The analog matrix supplies SLCD voltage. The SLCD voltage levels are generated by the
VSLCD pin or by the internal voltage step-up converter (depending on the VSRC bit in the
SLCD_CTL register). When using the internal voltage, the VSLCD value can be selected from
VSLCD0 to VSLCD7 by the CONR[2:0] bits in the SLCD_CFG register (Refer to the product
datasheet for the VSLCDx values). The application can adjust the contrast according to the
change of VSLCD value. The other way to adjust the contrast is by using the deadtime.
The analog matrix supplies intermediate voltage levels (1/3 VSLCD, 2/3 VSLCD or 1/4
VSLCD, 2/4 VSLCD, 3/4 VSLCD) between VSS and VSLCD through an internal resistor
divider network as shown in the figure 23-5.
Figure 23-5. Resistr divider network
RL
RH
HD SLCDON
BIAS[1]
VSLCDrai l3
VSS
VSLCDrai l2
VSLCDrai l1
RL
RL
RL
RH
RH
RH
BIAS[0]
VSLCD
During the transitions, the low value resistors (RL) are switched on to increase the current in
order to quickly reach the static state. Then the low value resistors (RL) are switched off, the
high value resistors (RH) are used to reduce the power. The length of the time during RL is
switched on depend on the PULSE[2:0] bits in the SLCD_CFG register. The RL can be always
switched on according to setting the HDEN bit in the SLCD_CFG register.
GD32F1x0 User Manual
618
External decoupling:
The VSLCD intermediate voltage rails (VSLCDrail1, VSLCDrail2, VSLCDrail3 in the figure 23-
5) can be connect to the GPIOs by configuring the SLCD_DECA bits of the SYSCFG_CFG1
register. Adding decoupling capacitors on these GPIOs helps to get a steady voltage resulting
in a higher contrast. Thus the PULSE[2:0] is allowed to select low value to reduce the power.
Note: When using VSLCDrail function, GPIO should be configured to analog input mode. The
segment AFIO and VSLCDrail decoupling functions cannot be used simultaneously.
Table 23-4. VSLCDrail connect pins
BIAS
Pin
1/2
1/3
1/4
VSLCDrail1
1/2VSLCD
1/3VSLCD
1/4VSLCD
PB12
VSLCDrail2
1/2VSLCD
2/3VSLCD
1/2VSLCD
PB2
VSLCDrail3
1/2VSLCD
2/3VSLCD
3/4VSLCD
PB0
23.4. SLCD registers
23.4.1. Control register (SLCD_CTL)
Address offset: 0x00
Reset value: 0x0000 0000
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
COMS
BIAS[1:0]
DUTY[2:0]
VSRC
SLCDON
rw rw
rw
rw
rw
Bits
Fields
Descriptions
31:8
Reserved
Must be kept at reset value
7
COMS
common/segment pad select
This bit is used to common/segment pad selection. When duty selects 1/8 or 1/6,
SLCD_COM[7:4] pad is always select SLCD_COM[7:4] function whatever this bit is
set or reset.
0: SLCD_COM[7:4] pad select SLCD_COM[7:4]
1: SLCD_COM[7:4] pad select SLCD_SEG[31:28]
6:5
BIAS[1:0]
Bias select
Bias is the number of voltage levels used when driving a SLCD. It is defined as 1/
(number of voltage levels used to drive an SLCD display - 1).
GD32F1x0 User Manual
619
00: 1/4 Bias (5 voltage levels: VSS, 1/4VSLCD, 1/2VSLCD, 3/4VSLCD, VSLCD)
01: 1/2 Bias (3 voltage levels: VSS, 1/2VSLCD, VSLCD)
10: 1/3 Bias (4 voltage levels: VSS, 1/3VSLCD, 2/3VSLCD, VSLCD)
11: Reserved
4:2
DUTY[2:0]
Duty select
These bits determine the duty cycle. Duty is the number defined as 1/(number of
common terminals on a given SLCD display).
000: Static duty
001: 1/2 duty
010: 1/3 duty
011: 1/4 duty
100: 1/8 duty
101: 1/6 duty
110: Reserved
111: Reserved
1
VSRC
SLCD Voltage source
Set this bit determines which is the SLCD voltage source.
0: Internal source
1: External source (VSLCD pin)
0
SLCDON
SLCD controller start
Set this bit by software to start SLCD controller. Clear this bit by software to stop
SLCD controller and the SLCD controller stop at the beginning of the next frame.
0: SLCD Controller stop
1: SLCD Controller start
23.4.2. Configuration register (SLCD_CFG)
Address offset: 0x04
Reset value: 0x0000 0000
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
PSC[3:0]
DIV[3:0]
BLKMOD[1:0]
rw rw rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
BLKDIV[2:0]
CONR[2:0]
DTD[2:0]
PULSE[2:0]
UPDIE
Reserved
SOFIE
HDEN
rw rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31:26
Reserved
Must be kept at reset value
25:22
PSC[3:0]
SLCD clock prescaler
GD32F1x0 User Manual
620
Set these bits define the prescaler of SLCD clock.
0000: fPSC = fin_clk
0001: fPSC = fin_clk/2
0010: fPSC = fin_clk/4
...
1111: fPSC = fin_clk/32768
21:18
DIV[3:0]
SLCD clock divider
Set these bits define the division factor of the DIV divider.
0000: fSLCD = fPSC/16
0001: fSLCD = fPSC/17
0010: fSLCD = fPSC/18
...
1111: fSLCD = fPSC/31
17:16
BLKMOD[1:0]
Blink mode
00: No Blink
01: Blink on SEG[0], COM[0] (1 pixel)
10: Blink on SEG[0], all COMs (up to 8 pixels depending on the programmed duty)
11: Blink on all SEGs and all COMs (all pixels)
15:13
BLKDIV[2:0]
Blink frequency divider
000: fBLINK = fSLCD/8
001: fBLINK = fSLCD/16
010: fBLINK = fSLCD /32
011: fBLINK = fSLCD /64
100: fBLINK = fSLCD/128
101: fBLINK = fSLCD/256
110: fBLINK = fSLCD/512
111: fBLINK = fSLCD/1024
12:10
CONR[2:0]
Contrast ratio
When chosing the internal voltage source (VSRC=0), these bits specify the VSLCD
voltage. It ranges from VSLCD0 to VSLCD7(typical 2.75 V to 5.20V), Refer to the
product datasheet for the VSLCDx values. When chosing the external voltage
source (VSRC=1), these bits is invalid.
000: VSLCD0
001: VSLCD1
010: VSLCD2
011: VSLCD3
100: VSLCD4
101: VSLCD5
110: VSLCD6
111: VSLCD7
9:7
DTD[2:0]
Dead time duration
GD32F1x0 User Manual
621
Set these bits configure the length of the dead time between frames.
000: No dead time
001: 1 phase dead time
010: 2 phase dead time
...
111: 7 phase dead time
6:4
PULSE[2:0]
Pulse ON duration
Set these bits define the pulse duration in terms of PSC pulses.
000: 0
001: 1/fPSC
010: 2/fPSC
011: 3/fPSC
100: 4/fPSC
101: 5/fPSC
110: 6/fPSC
111: 7/fPSC
3
UPDIE
SLCD update done interrupt enable
This bit is set and cleared by software.
0: SLCD Update Done interrupt disabled
1: SLCD Update Done interrupt enabled
2
Reserved
Must be kept at reset value
1
SOFIE
Start of frame interrupt enable
This bit is set and cleared by software.
0: SLCD Start of Frame interrupt disabled
1: SLCD Start of Frame interrupt enabled
0
HDEN
High drive enable
This bit is set and cleared by software.
0: Permanent high drive disabled. The time during which RL is enabled is configured
by the PULSE[2:0].
1: Permanent high drive enabled. RL is always switched on, and the PULSE[2:0] is
invalid.
23.4.3. Status flag register (SLCD_STAT)
Address offset: 0x08
Reset value: 0x0000 0020
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
GD32F1x0 User Manual
622
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
SYNF
VRDYF
UPDF
UPRF
SOF
ONF
r
r
r
rs
r
r
Bits
Fields
Descriptions
31:6
Reserved
Must be kept at reset value
5
SYNF
SLCD_CFG register synchronization flag
This bit is set when SLCD_CFG register update to SLCD clock domain, and It is
cleared by hardware when writing to the SLCD_CFG register.
0: SLCD_CFG Register not yet synchronized
1: SLCD_CFG Register synchronized to SLCD clock domain
4
VRDYF
SLCD voltage ready flag
This bit is set and cleared by the hardware according to the SLCD voltage.
0: SLCD voltage Is not ready
1: Step-up converter is enabled and ready to provide the correct voltage
3
UPDF
Update SLCD data done flag
This bit is set by hardware when update SLCD data done. It is cleared by writing 1
to the UPDC bit in the SLCD_STATC register.
0: No effect
1: SLCD data update done
2
UPRF
Update SLCD data request flag
After modifying the the first buffer by the SLCD_DATAx registers, the application
should set this bit to transfer the data to the second buffer. This bit stays set until the
transfer is complete, the SLCD_DATAx register is write protected during this time.
0: No effect
1: Request SLCD data update
1
SOF
Start of frame flag
This bit is set by hardware at the beginning of a new frame. It is cleared by writing 1
to the SOFC bit in the SLCD_STATC register.
0: No effect
1: Start of Frame flag
0
ONF
SLCD controller on flag
This bit is set by hardware when SLCDON is set to 1, it is cleard by hardware after
the SLCDON is cleared and the last frame is displayed.
0: SLCD Controller disabled.
1: SLCD Controller enabled
23.4.4. Status flag clear register (SLCD_STATC)
Address offset: 0x0C
GD32F1x0 User Manual
623
Reset value: 0x0000 0000
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
UPDC
Reserved
SOFC
Reserved
rc_w1
rc_w1
Bits
Fields
Descriptions
31:4
Reserved
Must be kept at reset value
3
UPDC
SLCD data update done clear bit
Set this bit to clear the UPDF flag in SLCD_STAT register.
0: No effect
1: Clear UPDF flag
2
Reserved
Must be kept at reset value
1
SOFC
Start of frame flag clear
Set this bit to clear the SOF flag in the SLCD_STAT register.
0: No effect
1: Clear SOF flag
0
Reserved
Must be kept at reset value
23.4.5. Display data registers (SLCD_DATAx, x=0~7)
Address offset: 0x14+0x08*(x+1)
Reset value: 0x0000 0000
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
SEG_DATAx[31:16]
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
SEG_DATAx[15:0]
rw
Bits
Fields
Descriptions
31:0
SEG_DATAx[31:0]
Each bit corresponds to one pixel to display.
0: Pixel inactive
1: Pixel active
GD32F1x0 User Manual
624
24. Operational amplifiers (OPA)/ Programmable curre
nt and voltage reference (IVREF)
This chapter applies to GD32F170xx and GD32F190xx devices.
24.1. Operational amplifiers (OPA)
24.1.1. Introduction
There are three operational amplifiers in the MCU and the operational amplifiers can be able
to route to external or internal follower.
When an operational amplifier is enabled, there will be a corresponding ADC channel used
to output measurement outcome.
24.1.2. Main features
Rail-to-rail input and output voltage range
Low input bias current
Low input offset voltage
Low power mode
24.1.3. Function description
Signal routing
The connections with dedicated I/O are listed below:
OPA0_VINP——>PA1
OPA0_VINM——>PA2
OPA0_VOUT——>PA3
OPA1_VINP——>PA6
OPA1_VINM——>PA7
OPA1_VOUT——>PB0
OPA2_VINP——>PC1
OPA2_VINM——>PC2
OPA2_VOUT——>PC3
GD32F1x0 User Manual
625
Figure 24-1. OPA0 Signal Route
ADC
switch
matrix
OPA0
S3
S2
S1
T3
DAC0
PA1
PA2
PA3
Figure 24-2. OPA1 Signal Route
ADC
switch
matrix
OPA1
S3
S2
S1
T3
DAC0
PA6
PA7
PB0
S4
DAC1
Figure 24-3. OPA2 Signal Route
ADC
switch
matrix
OPA2
S3
S2
S1
T3
DAC1
PC1
PC2
PC3
OPA_CTL register can select the routing for the three operational amplifiers.
For OPA0-2, S3/S4 is used to connect DAC0/DAC1 to their positive input.
GD32F1x0 User Manual
626
The OPAx_PD bit can be used to power down all operational amplifiers.
Calibration
Before leaving factory, the default factory trimming values are stored in nonvolatile memory
and used to initialize the operational amplifier offset. But also the chip support software using
the user value to trim the operational amplifier offset.
During trimming operation, all switches related to the inputs of each operational amplifier must
be disconnected.
Each operational amplifier has two operation modes: normal mode and low-power mode. The
different mode can configure different user trimming value in different register. The trimming
value is a 30-bit value for each mode of each operational amplifier. Writing 1 to OT_USER bit
will switch the trimming value to user configured values. This will take effect for all the
operational amplifiers.
Following steps are the commendatory procedure for either one of operational amplifier:
1). Configure control register to disconnected all the switches to the operational amplifier
2). Set the OT_USER bit to 1
3). Choose one calibration mode in below table:
For example: Operational amplifier-1, Normal mode offset cal low
Configure like this:
OPA0PD=0, OPA0LPM=0, OPA0CAL_H=0, OPA0CAL_L=1
4). Write trimming values in OPA0_TRIM_LOW. The writing value should be start from
00000b to the first value that causes the OPA0CALOUT bit set to 1.
Note: After writing trimming values into trimming register and before check CALOUT bit,
software should wait for the tofftrimmax delay specified in datasheet.
When got the correct trimming values, the values must be kept in trimming register.
Repeat step 3 and 4 for complete the whole operational amplifier calibration procedure:
- Normal mode calibration high,
- Low-power mode calibration low,
- Low-power mode calibration high.
Note: During the whole process of calibration, the external connection of operational amplifier
output must not pull-up or pull-down current higher than 500uA.
Table 24-1. Operating mode and calibration
Mode
Control Bits
Output
OPAxPD
OPAxLPM
OPAxCAL_H
OPAxCAL_L
VOUT
CALOUT
Normal
0
0
0
0
analog
0
1
1
Low-
power
0
1
0
0
analog
0
1
1
GD32F1x0 User Manual
627
Power-
down
1
X
X
X
Z
0
Offset
cal-high
0
X
1
0
analog
X
Offset
cal-low
0
X
0
1
analog
X
24.1.4. OPA register
Control register (OPA_CTL)
Address offset: 0x5C
Reset value: 0x0001 0101
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
OPA2CAL
OUT
OPA1CAL
OUT
OPA0CAL
OUT
OPA_
RANG
E
S4OPA
1
Reserved
OPA2
LPM
OPA2
CAL_H
OPA2CA
L_L
S3O
PA2
S2O
PA2
S1O
PA2
T3O
PA2
OPA2
PD
r
r
r
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
OPA1LP
M
OPA1CAL
_H
OPA1CAL
_L
S3OP
A1
S2OP
A1
S1OP
A1
T3OP
A1
OPA
1PD
OPA0
LPM
OPA0CA
L_H
OPA0
CAL_L
S3O
PA0
S2O
PA0
S1O
PA0
T3O
PA0
OPA0
PD
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31
OPA2CALOUT
OPA2 calibration output
When in calibration mode, if offset is trimmed the flag will assert.
30
OPA1CALOUT
OPA1 calibration output
When in calibration mode, if offset is trimmed the flag will assert.
29
OPA0CALOUT
OPA0 calibration output
When in calibration mode, if offset is trimmed the flag will assert.
28
OPA_RANGE
Power supply range
This bit can be set and cleared by software when the operational amplifiers are in
powered down. It select the operational amplifier power supply range for stability
0: Low range (VDDA < 3.3 V)
1: High range (VDDA > 3.3 V)
27
S4OPA1
S4 switch enable for OPA1
0: S4 switch opened
1: S4 switch closed
26:24
Reserved
Must be kept at reset value
23
OPA2LPM
OPA2 low power mode
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0: OPA2 low power mode off
1: OPA2 low power mode on
22
OPA2CAL_H
OPA2 offset calibration for N diff
0: OPA2 offset calibration for N diff OFF
1: OPA2 offset calibration for N diff ON if OPA2CAL_L = 0
21
OPA2CAL_L
OPA2 offset calibration for P diff
0: OPA2 offset calibration for P diff OFF
1: OPA2 offset calibration for P diff ON if OPA2CAL_H = 0
20
S3OPA2
S3 switch enable for OPA2
0: S3 switch opened
1: S3 switch closed
19
S2OPA2
S2 switch enable for OPA2
0: S2 switch opened
1: S2 switch closed
18
S1OPA2
S1 switch enable for OPA2
0: S1 switch opened
1: S1 switch closed
17
T3OPA2
T3 switch enable for OPA2
0: T3 switch opened
1: T3 switch closed
16
OPA2PD
OPA2 power down
0: OPA2 enabled
1: OPA2 disabled
15
OPA1LPM
OPA1 low power mode
0: OPA1 low power mode off
1: OPA1 low power mode on
14
OPA1CAL_H
OPA1 offset calibration for N diff
0: OPA1 offset calibration for N diff OFF
1: OPA1 offset calibration for N diff ON if OPA1CAL_L = 0
13
OPA1CAL_L
OPA1 offset calibration for P diff
0: OPA1 offset calibration for P diff OFF
1: OPA1 offset calibration for P diff ON if OPA1CAL_H = 0
12
S3OPA1
S3 switch enable for OPA1
0: S3 switch opened
1: S3 switch closed
11
S2OPA1
S2 switch enable for OPA1
0: S2 switch opened
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1: S2 switch closed
10
S1OPA1
S1 switch enable for OPA1
0: S1 switch opened
1: S1 switch closed
9
T3OPA1
T3 switch enable for OPA1
0: T3 switch opened
1: T3 switch closed
8
OPA1PD
OPA1 power down
0: OPA1 enabled
1: OPA1 disabled
7
OPA0LPM
OPA0 low power mode
0: OPA0 low power mode off
1: OPA0 low power mode on
6
OPA0CAL_H
OPA0 offset calibration for N diff
0: OPA0 offset calibration for N diff OFF
1: OPA0 offset calibration for N diff ON if OPA0CAL_L = 0
5
OPA0CAL_L
OPA0 offset calibration for P diff
0: OPA0 offset calibration for P diff OFF
1: OPA0 offset calibration for P diff ON if OPA0CAL_H = 0
4
S3OPA0
S3 switch enable for OPA0
0: S3 switch opened
1: S3 switch closed
3
S2OPA0
S2 switch enable for OPA0
0: S2 switch opened
1: S2 switch closed
2
S1OPA0
S1 switch enable for OPA0
0: S1 switch opened
1: S1 switch closed
1
T3OPA0
T3 switch enable for OPA0
0: T3 switch opened
1: T3 switch closed
0
OPA0PD
OPA0 power down
0: OPA0 enabled
1: OPA0 disabled
Bias trimming register for normal mode (OPA_BT)
Address offset: 0x60
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Reset value: 0x0000 0000
This register has to be accessed by word (32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
OT_USE
R
Reserved
OA2_TRIM_HIGH[4:0]
OA2_TRIM_LOW[4:0]
OA1_TRIM_HIGH[4:1]
w
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
OA1_
TRIM_HI
GH[0]
OA1 _TRIM_LOW[4:0]
OA0 _TRIM_HIGH[4:0]
OA0 _TRIM_LOW[4:0]
rw
rw
rw
rw
Bits
Fields
Descriptions
31
OT_USER
This bit is set and cleared by software; it is always read as 0. It is used to select
if the OPAx offset is trimmed by the preset factory-programmed trimming values
or the user programmed trimming value.
0: Trim the OPA offset using default factory values
1: Trim the OPA offset using user programmed values
30
Reserved
Must be kept at reset value
29:25
OA2_TRIM_HIGH[4:0]
OPA2, normal mode 5-bit offset trim value for NMOS pairs
24:20
OA2_TRIM_LOW[4:0]
OPA2, normal mode 5-bit offset trim value for PMOS pairs
19:15
OA1_TRIM_HIGH[4:0]
OPA1, normal mode 5-bit offset trim value for NMOS pairs
14:10
OA1_TRIM_LOW[4:0]
OPA1, normal mode 5-bit offset trim value for PMOS pairs
9:5
OA0_TRIM_HIGH[4:0]
OPA0, normal mode 5-bit offset trim value for NMOS pairs
4:0
OA0_TRIM_LOW[4:0]
OPA0, normal mode 5-bit offset trim value for PMOS pairs
Bias trimming register for low power mode (OPA_LPBT)
Address offset: 0x64
Reset value: 0x0000 0000
This register has to be accessed by word (32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
OA2_TRIM_LP_HIGH[4:0]
OA2_TRIM_ LP_LOW[4:0]
OA1_TRIM_ LP_HIGH[4:1]
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
OA1_
TRIM_
LP_HIGH[0]
OA1 _TRIM_ LP_LOW[4:0]
OA0 _TRIM_ LP_HIGH[4:0]
OA0 _TRIM_ LP_LOW[4:0]
rw
rw
rw
rw
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Bits
Fields
Descriptions
31:30
Reserved
Must be kept at reset value
29:25
OA2_TRIM_LP_HIG
H[4:0]
OPA2, low-power mode 5-bit offset trim value for NMOS pairs
24:20
OA2_TRIM_
LP_LOW[4:0]
OPA2, low-power mode 5-bit offset trim value for PMOS pairs
19:15
OA1_TRIM_
LP_HIGH[4:0]
OPA1, low-power mode 5-bit offset trim value for NMOS pairs
14:10
OA1_TRIM_
LP_LOW[4:0]
OPA1, low-power mode 5-bit offset trim value for PMOS pairs
9:5
OA0_TRIM_
LP_HIGH[4:0]
OPA0, low-power mode 5-bit offset trim value for NMOS pairs
4:0
OA0_TRIM_
LP_LOW[4:0]
OPA0, low-power mode 5-bit offset trim value for PMOS pairs
24.2. Programmable Current and Voltage Reference (IVREF)
24.2.1. Introduction
An application programmable current reference module is included in the MCU.
When users want to use current reference, there are two different running modes are supplied.
One mode named Low Power Mode and another one named High Current Mode.
The difference between two modes is the current step and maximum current.
The former’s (LPM) step current is 1uA and the latter’s (HCM) 8uA.
The former’s (LPM) maximum current is 63uA and the latter’s (HCM) 504uA.
There is still a voltage reference module in the MCU which can provide a 2.5V voltage.
24.2.2. Main features
Current Reference feature:
Programmable current
Programmable Source or sink
Low Power Mode and High Current Mode
Voltage Reference feature:
User programmable trim
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24.2.3. Function description
Signal routing
IREF PB0
When IREF is used, the PB0 pin should be configured to analog input mode.
VREF PB1
When VREF is used, the PB1 pin should be configured as an analog I/O and external VREF
decoupling capacitors are recommended.
User Trimming
User can trim the IREF outputting current by programming IREF_TRIM and can trim the
voltage by programming VREF_TRIM.
24.2.4. IVREF registers
Control register (IVREF_CTL)
Address offset: 0x300
Reset value: 0x1000 0F00
This register has to be accessed by word (32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
VREN
DECAP
Reserved
VPT[4:0]
Reserved
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
CREN
SSEL
Reserved
CPT[4:0]
SCMOD
Reserved
CSDT[5:0]
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31
VREN
Voltage Reference Enable
0: Disable Voltage Reference
1: Enable Voltage Reference
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30
DECAP
Disconnect external capacitor
0: Connect external capacitor
1: Disconnect external capacitor
29
Reserved
Must be kept at reset value
28:24
VPT[4:0]
Voltage precision trim
00000: -6.4%
00001: -6.0%
….
11110: +5.6%
11111: +6%
23:16
Reserved
Must be kept at reset value
15
CREN
Current Reference Enable.
0: Disable current reference
1: Enable current reference
14
SSEL
Step selection
0: Low power, 1uA step
1: High current, 8uA step
13
Reserved
Must be kept at reset value
12:8
CPT[4:0]
Current precision trim
00000: -15%
….
11111: +16%
7
SCMOD
Sink current mode
0: Source current
1: Sink current
6
Reserved
Must be kept at reset value
5:0
CSDT[5:0]
Current step data
000000: Default value.
000001: Step * 1
….
111111: Step * 63
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25. Controller area network (CAN)
This chapter applies to GD32F170xx and GD32F190xx devices.
25.1. Introduction
CAN bus (for controller area network) is a bus standard designed to allow microcontrollers
and devices to communicate with each other without a host computer.
The Basic Extended CAN (CAN), interfaces the CAN network. It supports the CAN protocols
version 2.0A and B. The CAN interface handles the transmission and the reception of CAN
frames fully autonomously. The CAN provides 28 scalable/configurable identifier filter banks.
The filters are for selecting the incoming messages the software needs and discarding the
others. Three transmit mailboxes are provided to the software for setting up messages. The
transmission Scheduler decides which mailbox has to be transmitted first. Three complete
messages can be stored in each FIFO. The FIFOs are managed completely by hardware.
Two receive FIFOs are used by hardware to store the incoming messages. The CAN
controller also provides all hardware functions for supporting the time-triggered
communication option for safety-critical applications.
25.2. Main features
Supports CAN protocols version 2.0A, B
Baud rates up to 1 Mbit/s
Supports the time-triggered communication
Maskable interrupts
Transmission
3 transmit mailboxes
Prioritization of messages
Time Stamp on SOF transmission
Reception
2 receive FIFOs with 3 messages deep
28 scalable/configurable identifier filter banks
FIFO lock
Time-triggered communication
Disable retransmission automatically
16-bit free timer
Time Stamp on SOF reception
Time Stamp sent in last two data bytes
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25.3. Function description
Figure below shows the CAN block diagram.
Figure 25-1. CAN module block diagram
CAN0 Transmit
mailbox[0..2] Receive
FIFO[0..1]
CAN1 Transmit
mailbox[0..2] Receive
FIFO[0..1]
CAN0 Tx/Rx
CAN1 Tx/Rx
Mailbox 2
Mailbox 1
Mailbox 0
Mailbox 2
Mailbox 1
Mailbox 0
25.3.1. Working mode
The CAN interface has three working modes:
Sleep working mode
Initial working mode
Normal working mode
Sleep working mode
Sleep working mode is the default mode after reset. Also, sleep working mode is in the low-
power status while the CAN clock is stopped.
When SLPWMOD bit in CAN_CTL register is set, the CAN enters the sleep working mode.
Then the SLPWS bit in CAN_STAT register is set.
To leave sleep working mode automatically: the AWU bit in CAN_CTL register is set. To leave
sleep working mode by software: clear the SLPWMOD bit in CAN_CTL register.
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Initial working mode
The CAN enters initial working mode whenever the options of CAN bus communication need
to be changed.
Set IWMOD bit in CAN_CTL register to enter initial working mode or clear it in order to leave.
Normal working mode
After initialization, the CAN can enter normal working mode and is ready to communicate with
other CAN communication nodes.
To enter normal working mode: clear IWMOD bit in CAN_CTL register.
25.3.2. Communication modes
The CAN interface has four communication modes:
Silent communication mode
Loopback communication mode
Loopback and silent communication mode
Normal communication mode
Silent communication mode
Silent communication mode means reception available and transmission disable.
The Rx pin of the CAN can get the signal from the network and the Tx pin always holds logical
one.
When the SCMOD bit in CAN_BT register is set, the CAN enters the silent communication
mode. When it is cleared, the CAN leaves silent communication mode.
Silent communication mode is useful on monitoring the network messages.
Loopback communication mode
Loopback communication mode means the sending messages are transferred into the
reception FIFOs.
Set LCMOD bit in CAN_BT register to enter loopback communication mode or clear it to leave.
Loopback communication mode is useful on self-test.
Loopback and silent communication mode
Loopback and silent communication mode means the RX and TX pins are disconnected from
the CAN network while the sending messages are transformed into the reception FIFOs.
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Set LCMOD and SCMOD bit in CAN_BT register to enter loopback and silent communication
mode or clear them to leave.
Loopback and silent communication mode is useful on self-test. The TX pin holds logical one.
The RX pin holds high impedance state.
Normal communication mode
Normal communication mode is the default communication mode unless the LCMOD or
SCMOD bit in CAN_BT register is set.
25.3.3. Data transmission
Transmission register
Three transmit mailboxes are transparent to the application. You can use transmit mailboxes
through four registers: CAN_TMIx, CAN_TMPx, CAN_TMDATA0x and CAN_TMDATA1x. As
shown in figure below.
Figure 25-2. Transmission register
Application
Transmit
mailbox 0
Transmit
mailbox 1
Transmit
mailbox 2
TMI2
TMP2
TMDATA02
TMDATA12
TMI0
TMP0
TMDATA00
TMDATA10
TMI1
TMP1
TMDATA01
TMDATA11
Transmit mailbox state
A transmit mailbox can be used when it is free: empty state. If the data is filled in the mailbox,
setting TEN bit in CAN_TMIx register to prepare for starting the transmission: pending state.
If more than one mailbox is in the pending state, they need schedule the transmission:
scheduled state. A mailbox with priority enter transmit state and start transmitting the
message. After the message has been sent, the mailbox is free: empty state. As shown in
figure below.
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Figure 25-3. State of transmission mailbox
empty
pending scheduled
transmit
Transmit status and error
The CAN_TSTAT register includes the transmit status and error bits: MTF, MTFNERR, MAL,
MTE.
MTF: mailbox transmits finished. Typically, MTF is set when the frame in the transmit
mailbox has been sent.
MTFNERR: mailbox transmits finished and no error. MTFNERR is set when the frame in
the transmission mailbox has been sent.
MAL: mailbox arbitration lost. MAL is set while the frame transmission is failed because
of the arbitration lost.
MTE: mailbox transmits error. MTE is set while the frame transmission is failed because
of the detection error of CAN bus.
Steps of sending a frame
To send a frame through the CAN:
Step 1: Select one free transmit mailbox.
Step 2: Fill four registers with the application’s acquirement.
Step 3: Set TEN bit in CAN_TMIx register.
Step 4: Check the transmit status. Typically, MTF and MTFNERR are set if transmission is
successful.
Transmission options
Abort
MST bit in CAN_TSTAT register can abort the transmission.
If the transmission mailbox’s state is pending or scheduled, the abort of transmission can
be done immediately.
In the state of transmit the abort of transmission has two results. In case of transmission
successful, the MTFNERR and MTF in CAN_TSTAT are set and state changes to empty. In
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case of transmission failed, the state changes to be scheduled and then the abort of
transmission can be done immediately.
Priority
When more than one transmit mailbox is pending, the transmission order is given by the TFO
bit in CAN_CTL register.
In case TFO is 1, the three transmit mailboxes work as FIFO.
In case TFO is 0, the transmit mailbox with lowest identifier has the highest priority of
transmission. If the identifiers are equal, the lower mailbox number will be scheduled first.
25.3.4. Data reception
Reception register
Two receive FIFOs are transparent to the application. You can use receive FIFOs through
five registers: CAN_RFIFOx, CAN_RFIFOMIx, CAN_RFIFOMPx, CAN_RFIFOMDATA0x and
CAN_RFIFOMDATA1x. FIFO’s status and operation can be handled by CAN_RFIFOx
register. Reception frame data can be achieved through the registers: CAN_RFIFOMIx,
CAN_RFIFOMPx, CAN_RFIFOMDATA0x and CAN_RFIFOMDATA1x.
Each FIFO consists of three receive mailboxes. As shown in figure below.
Figure 25-4. Reception register
Application
Receive FIFO0
Receive FIFO1
RFIFOMI0
RFIFOMP0
RFIFOMDATA00
RFIFOMDATA10
RFIFOMI1
RFIFOMP1
RFIFOMDATA01
RFIFOMDATA11
Mailbox 0
Mailbox 1
Mailbox 2
Mailbox 0
Mailbox 1
Mailbox 2
RFIFO0
RFIFO1
Receive FIFO
Receive FIFO has three mailboxes. The reception frames are stored in the mailbox ordered
by the arriving sequence of the frames. First arrived frame can be accessed by application
firstly.
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The number of frames in the receive FIFO and the status can be accessed by the register
CAN_RFIFO0 and CAN_RFIFO1.
If at least one frame has been stored in the receive FIFO0, set RFD bit in CAN_RFIFO0 to
read one frame from receive FIFO. The frame data is placed in the registers (CAN_RFIFOMI0,
CAN_RFIFOMP0, CAN_RFIFOMDATA00, CAN_RFIFOMDATA10) until the RFD bit in
CAN_RFIFO0 register is cleared.
Receive FIFO status
RFL bit in CAN_RFIFOx register: receive FIFO length. It is 0 when no frame is stored in the
reception FIFO and 3 when full.
RFF bit in CAN_RFIFOx register: the FIFO holds three frames.
RFO bit in CAN_RFIFOx register: one new frame arrived while the FIFO has hold three frames.
Steps of receiving a message
Step 1: Check the number of frames in the receive FIFO.
Step 2: Set the RFD bit in CAN_RFIFOx register.
Step 3: Wait for reading CAN_RFIFOMIx, CAN_RFIFOMPx, CAN_RFIFOMDATA0x and
CAN_RFIFOMDATA1x until the RFD bit is cleared.
25.3.5. Filtering Function
The CAN would receive frames from the CAN bus. If the frame is passed through the filter, it
is copied into the receive FIFOs. Otherwise, the frame will be discarded without intervention
by the software.
The identifier of frame from the CAN bus takes part in the matching of the filter.
Scale
Each filter bank can be configured 32-bit or 16-bit.
32-bit: SFID[10:0], EFID[17:0], FF and FT bits. As shown in figure below.
Figure 25-5. 32-bit filter
16-bit: SFID [10:0], FT, FF and EFID[17:15] bits. As shown in figure below.
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Figure 25-6. 16-bit filter
Mask mode
In mask mode the identifier registers are associated with mask registers specifying which bits
of the identifier are handled as “must match” or as “don’t care”. 32-bit mask mode example is
shown in figure below.
Figure 25-7. 32-bit mask mode filter
List mode
The filter consists of frame identifiers. The filter can decide whether a frame will be discarded
or not. When one frame arrived, the filter will check which member can match the identifier of
the frame.
32-bit list mode example is shown in figure below.
Figure 25-8. 32-bit list mode filter
Filter number
Each filter within a filter bank is numbered from 0 to a maximum dependent on the mode and
the scale of each of the filter banks.
For example, there are two filter banks. Bank 0 is configured as 32-bit mask mode. Bank 1 is
configured as 16-bit list mode. The filter number is shown in figure below.
Figure 25-9. 32-bit filter number
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Associated FIFO
28 banks can be associated with FIFO0 or FIFO1. If the bank is associated with FIFO 0, the
frames passed through the bank will fill the FIFO0.
Active
The filter bank needs to be configured activation if the application wants the bank working
and while filters not used by the application should be left deactivated.
Filtering index
Each filter number corresponds to a filtering rule. When the frame from the CAN bus passes
the filters, a filter number must associate with the frame. The filter number is called filtering
index. It stores in the FI bit in CAN_RFIFOMPx when the frame is read by the application.
Each FIFO numbers the filters within the banks associated with the FIFO itself whatever the
bank is active or not.
The example about filtering index is shown in figure below.
Figure 25-10. Filtering index
Priority
The filters have the priority:
1. 32-bit mode is higher than 16-bit mode.
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2. List mode is higher than mask mode.
3. Smaller filter index value has the higher priority.
25.3.6. Time-triggered communication
The time-triggered CAN protocol is a higher layer protocol on top of the CAN (Controller Area
Network) data link layer. Time-triggered communication means that activities are triggered by
the elapsing of time segments. In a time-triggered communication system all points of time of
message transmission are defined during the development of a system. A time-triggered
communication system is ideal for applications in which the data traffic is of a periodic nature.
In this mode, the 16-bit internal counter of the CAN hardware is activated and used to
generate the time stamp value stored in the CAN_RFIFOMPx and CAN_TMPx registers for
reception and transmission respectively. The internal counter is incremented each CAN bit
time. The internal counter is captured on the sample point of the SOF (Start of Frame) bit in
both reception and transmission.
The automatic retransmission is disabled in the time-triggered CAN communication.
25.3.7. Communication parameters
Nonautomatic retransmission mode
This mode has been implemented in order to fulfill the requirement of the time-triggered
communication option of the CAN standard. To configure the hardware in this mode the ARD
bit in the CAN_CTL register must be set.
In this mode, each transmission is started only once. If the first attempt fails, due to an
arbitration loss or an error, the hardware will not automatically restart the frame transmission.
At the end of the first transmission attempt, the hardware considers the request as finished
and sets the MTF bit in the CAN_TSTAT register. The result of the transmission is indicated
in the CAN_TSTAT register by the MTFNERR, MAL and MTE bits.
Bit time
On the bit-level the CAN protocol uses synchronous bit transmission. This not only enhances
the transmitting capacity but also means that a sophisticated method of bit synchronization is
required. While bit synchronization in a character-oriented transmission (asynchronous) is
performed upon the reception of the start bit available with each character, a synchronous
transmission protocol there is just one start bit available at the beginning of a frame. To ensure
the receiver to correctly read the messages, continuous resynchronization is required. Phase
buffer segments are therefore inserted before and after the nominal sample point within a bit
interval.
The CAN protocol regulates bus access by bit-wise arbitration. The signal propagation from
sender to receiver and back to the sender must be completed within one bit-time. For
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synchronization purposes a further time segment, the propagation delay segment, is needed
in addition to the time reserved for synchronization, the phase buffer segments. The
propagation delay segment takes into account the signal propagation on the bus as well as
signal delays caused by transmitting and receiving nodes.
The normal bit time simplified by the CAN from the CAN protocol has three segments as
follows:
Synchronization segment (SYNC_SEG): a bit change is expected to occur within this time
segment. It has a fixed length of one time quantum ().
Bit segment 1 (BS1): defines the location of the sample point. It includes the Propagation
delay segment and Phase buffer segment 1 of the CAN standard. Its duration is
programmable between 1 and 16 time quanta but may be automatically lengthened to
compensate for positive phase drifts due to differences in the frequency of the various nodes
of the network.
Bit segment 2 (BS2): defines the location of the transmit point. It represents the Phase buffer
segment 2 of the CAN standard. Its duration is programmable between 1 and 8 time quanta
but may also be automatically shortened to compensate for negative phase drifts.
The bit time is shown as in the figure below.
Figure 25-11. The bit time
The resynchronization Jump Width (SJW) defines an upper bound to the amount of
lengthening or shortening of the bit segments. It is programmable between 1 and 4 time
quanta.
A valid edge is defined as the first transition in a bit time from dominant to recessive bus level
provided the controller itself does not send a recessive bit.
If a valid edge is detected in BS1 instead of SYNC_SEG, BS1 is extended by up to SJW so
that the sample point is delayed.
Conversely, if a valid edge is detected in BS2 instead of SYNC_SEG, BS2 is shortened by
up to SJW so that the transmit point is moved earlier.
Baud Rate
The CAN’s clock derives from the APB1 bus. The CAN calculates its baud rate as follow:
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 

   
with:
  
 
 
  
25.3.8. Error flags
The error management as described in the CAN protocol is handled entirely by hardware
using a Transmit Error Counter (TECNT value, in CAN_ERR register) and a Receive Error
Counter (RECNT value, in the CAN_ERR register), which get incremented or decremented
according to the error condition. For detailed information about TECNT and RECNT
management, please refer to the CAN standard.
Both of them may be read by software to determine the stability of the network.
Furthermore, the CAN hardware provides detailed information on the current error status in
CAN_ERR register. By means of the CAN_INTEN register (ERRIE bit, etc.), the software can
configure the interrupt generation on error detection in a very flexible way.
Bus-Off recovery
The Bus-Off state is reached when TECNT is greater than 255. This state is indicated by
BOERR bit in CAN_ERR register. In Bus-Off state, the CAN is no longer able to transmit and
receive messages.
Depending on the ABOR bit in the CAN_CTL register, CAN will recover from Bus-Off
(becomes error active again) either automatically or on software request. But in both cases
the CAN has to wait at least for the recovery sequence specified in the CAN standard (128
occurrences of 11 consecutive recessive bits monitored on CAN RX).
If ABOR is set, the CAN will start the recovering sequence automatically after it has entered
Bus-Off state.
If ABOR is cleared, the software must initiate the recovering sequence by requesting CAN to
enter and to leave initialization mode.
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25.3.9. CAN interrupts
Four interrupt vectors are dedicated to CAN. Each interrupt source can be independently
enabled or disabled seting or reseting related bits in CAN_INTEN.
The interrupt sources can be classified into:
transmit interrupt
FIFO0 interrupt
FIFO1 interrupt
error and status change interrupt
Transmit interrupt
The transmit interrupt can be generated by the following events:
– Transmit mailbox 0 becomes empty, MTF0 bit in the CAN_TSTAT register set.
– Transmit mailbox 1 becomes empty, MTF1 bit in the CAN_TSTAT register set.
– Transmit mailbox 2 becomes empty, MTF2 bit in the CAN_TSTAT register set.
FIFO0 interrupt
The FIFO0 interrupt can be generated by the following events:
– Reception of a new message, RFL0 bits in the CAN_RFIFO0 register are not ‘00’.
– FIFO0 full condition, RFF0 bit in the CAN_RFIFO0 register set.
– FIFO0 overrun condition, RFO0 bit in the CAN_RFIFO0 register set.
FIFO1 interrupt
The FIFO1 interrupt can be generated by the following events:
– Reception of a new message, RFL1 bits in the CAN_RFIFO1 register are not ‘00’.
– FIFO1 full condition, RFF1 bit in the CAN_RFIFO1 register set.
– FIFO1 overrun condition, RFO1 bit in the CAN_RFIFO1 register set.
Error and status change interrupt
The error and status change interrupt can be generated by the following events:
– Error condition, for more details on error conditions please refer to the CAN Error register
(CAN_ERR).
– Wakeup condition, SOF monitored on the CAN RX signal.
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– Enter into sleep mode.
25.3.10. CAN PHY mode
If set PHYEN bit in CAN_PHYCTL register, integrated CAN PHY is enabled. At this time the
internal transceiver will begin to work. This mode only used for CAN0.
1. The connection outside of MCU chip is refer to the figure as follows:
Figure 25-12. CAN PHY connection
PA5
PA6
diode
CANH
CANL
diode
diode
diode
2. Configure the PA5/PA6 to analog input mode.
3. Enable the CAN clock.
4. Set PHYEN bit and PDMODE if needed in CAN_PHYCTL register.
5. Configure CAN registers as usual, same as not in CAN PHY mode.
25.4. CAN registers
25.4.1. Control register (CAN_CTL)
Address offset: 0x00
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Reset value: 0x0001 0002
This register has to be accessed by word(32-bit).
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
DFZ
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
SWRST
Reserved
TTC
ABOR
AWU
ARD
RFOD
TFO
SLPWMOD
IWMOD
rs
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31:17
Reserved
Must be kept at reset value
16
DFZ
Debug freeze
0: CAN reception and transmission working during debug
1: CAN reception and transmission stop working during debug
15
SWRST
Software reset
0: Normal operation.
1: Reset CAN with working mode of sleep. This bit is automatically reset to 0.
14:8
Reserved
Must be kept at reset value
7
TTC
Time-triggered communication
0: Disable time-triggered communication
1: Enable time-triggered communication
6
ABOR
Automatic bus-off recovery
0: The bus-off state is left manually by software
1: The bus-off state is left automatically by hardware
5
AWU
Automatic wakeup
0: The sleeping working mode is left manually by software
1: The sleeping working mode is left automatically by hardware
4
ARD
Automatic retransmission disable
0: Enable Automatic retransmission
1: Disable Automatic retransmission
3
RFOD
Receive FIFO overwrite disable
0: Enable receive FIFO overwrite when receive FIFO is full and overwrite the FIFO
with the incoming frame
1: Disable receive FIFO overwrite when receive FIFO is full and discard the
incoming frame
2
TFO
Transmit FIFO order
0: Order with the identifier of the frame
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1: Order with first in and first out
1
SLPWMOD
Sleep working mode
0: Disable sleep working mode
1: Enable sleep working mode
0
IWMOD
Initial working mode
0: Disable initial working mode
1: Enable initial working mode
25.4.2. Status register (CAN_STAT)
Address offset: 0x04
Reset value: 0x0000 0C02
This register has to be accessed by word(32-bit).
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
RXL
LASTRX
RS
TS
Reserved
SLPIF
WUIF
ERRIF
SLPWS
IWS
r
r
r
r
rc_w1
rc_w1
rc_w1
r
r
Bits
Fields
Descriptions
31:12
Reserved
Must be kept at reset value
11
RXL
RX level
10
LASTRX
Last sample value of Rx pin
9
RS
Receiving state
0: CAN is not working in the receiving state
1: CAN is working in the receiving state
8
TS
Transmitting state
0: CAN is not working in the transmitting state
1: CAN is working in the transmitting state
7:5
Reserved
Must be kept at reset value
4
SLPIF
Status change interrupt flag of sleep working mode entering
0: CAN is not entering the sleep working mode
1: CAN is entering the sleep working mode. This bit is set while the interrupt is
enabling.
3
WUIF
Status change interrupt flag of wakeup from sleep working mode
0: Wakeup event is not coming
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1: Wakeup event is coming. This bit is set while the interrupt is enabling.
2
ERRIF
Error interrupt flag
0: No error interrupt
1: Any error interrupt has happened while the interrupt is enabling
1
SLPWS
Sleep working state
0: CAN is not the state of sleep working mode
1: CAN is the state of sleep working mode
0
IWS
Initial working state
0: CAN is not the state of initial working mode
1: CAN is the state of initial working mode
25.4.3. Transmit status register (CAN_TSTAT)
Address offset: 0x08
Reset value: 0x1C00 0000
This register has to be accessed by word(32-bit).
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
TMLS2
TMLS1
TMLS0
TME2
TME1
TME0
NUM[1:0]
MST2
Reserved
MTE2
MAL2
MTFNERR2
MTF2
r
r
r
r
r
r
r
rs
rc_w1
rc_w1
rc_w1
rc_w1
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
MST1
Reserved
MTE1
MAL1
MTFNERR1
MTF1
MST0
Reserved
MTE0
MAL0
MTFNERR0
MTF0
rs
rc_w1
rc_w1
rc_w1
rc_w1
rs
rc_w1
rc_w1
rc_w1
rc_w1
Bits
Fields
Descriptions
31
TMLS2
Transmit mailbox 2 last sending in transmit FIFO
This bit is set by hardware when transmit mailbox 2 has the last sending order in the
transmit FIFO with at least two frame are pending.
30
TMLS1
Transmit mailbox 1 last sending in transmit FIFO
This bit is set by hardware when transmit mailbox 1 has the last sending order in the
transmit FIFO with at least two frame are pending.
29
TMLS0
Transmit mailbox 0 last sending in transmit FIFO
This bit is set by hardware when transmit mailbox 0 has the last sending order in the
transmit FIFO with at least two frame are pending.
28
TME2
Transmit mailbox 2 empty
0: Transmit mailbox 2 not empty
1: Transmit mailbox 2 empty
27
TME1
Transmit mailbox 1 empty
0: Transmit mailbox 1 not empty
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1: Transmit mailbox 1 empty
26
TME0
Transmit mailbox 0 empty
0: Transmit mailbox 0 not empty
1: Transmit mailbox 0 empty
25:24
NUM[1:0]
These bits are the number of the transmit FIFO mailbox in which the frame will be
transmitted if at least one mailbox is empty.
These bits are the number of the transmit FIFO mailbox in which the frame will be
transmitted lastly if all mailboxes are full.
23
MST2
Mailbox 2 stop transmitting
This bit is set by the software to stop mailbox 2 transmitting.
This bit is reset by the hardware while the mailbox 2 is empty.
22:20
Reserved
Must be kept at reset value
19
MTE2
Mailbox 2 transmit error
This bit is set while the transmit error is occurred.
18
MAL2
Mailbox 2 arbitration lost
This bit is set while the arbitration lost is occurred.
17
MTFNERR2
Mailbox 2 transmit finished and no error
0: Mailbox 2 transmit finished with error
1: Mailbox 2 transmit finished and no error
16
MTF2
Mailbox 2 transmit finished
0: Mailbox 2 transmit is progressing
1: Mailbox 2 transmit finished
15
MST1
Mailbox 1 stop transmitting
This bit is set by the software to stop mailbox 1 transmitting.
This bit is reset by the hardware while the mailbox 1 is empty.
14:12
Reserved
Must be kept at reset value
11
MTE1
Mailbox 1 transmit error
This bit is set while the transmit error is occurred.
10
MAL1
Mailbox 1 arbitration lost
This bit is set while the arbitration lost is occurred.
9
MTFNERR1
Mailbox 1 transmit finished and no error
0: Mailbox 1 transmit finished with error
1: Mailbox 1 transmit finished and no error
8
MTF1
Mailbox 1 transmit finished
0: Mailbox 1 transmit is progressing
1: Mailbox 1 transmit finished
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7
MST0
Mailbox 0 stop transmitting
This bit is set by the software to stop mailbox 0 transmitting.
This bit is reset by the hardware while the mailbox 0 is empty.
6:4
Reserved
Must be kept at reset value
3
MTE0
Mailbox 0 transmit error
This bit is set while the transmit error is occurred.
2
MAL0
Mailbox 0 arbitration lost
This bit is set while the arbitration lost is occurred.
1
MTFNERR0
Mailbox 0 transmit finished and no error
0: Mailbox 0 transmit finished with error
1: Mailbox 0 transmit finished and no error
0
MTF0
Mailbox 0 transmit finished
0: Mailbox 0 transmit is progressing
1: Mailbox 0 transmit finished
25.4.4. Receive message FIFO0 register (CAN_RFIFO0)
Address offset: 0x0C
Reset value: 0x0000 0000
This register has to be accessed by word(32-bit).
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
RFD0
RFO0
RFF0
Reserved
RFL0[1:0]
rs
rc_w1
rc_w1
r
Bits
Fields
Descriptions
31:6
Reserved
Must be kept at reset value
5
RFD0
Receive FIFO 0 dequeue
This bit is set by the software to start dequeuing a frame from receive FIFO 0.
This bit is reset by the hardware while the dequeuing is done.
4
RFO0
Receive FIFO 0 overfull
0: The receive FIFO 0 is not overfull
1: The receive FIFO 0 is overfull
3
RFF0
Receive FIFO 0 full
0: The receive FIFO 0 is not full
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1: The receive FIFO 0 is full
2
Reserved
Must be kept at reset value
1:0
RFL0[1:0]
Receive FIFO 0 length
These bits are the length of the receive FIFO0.
25.4.5. Receive message FIFO1 register (CAN_RFIFO1)
Address offset: 0x10
Reset value: 0x0000 0000
This register has to be accessed by word(32-bit).
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
RFD1
RFO1
RFF1
Reserved
RFL1[1:0]
rs
rc_w1
rc_w1
r
Bits
Fields
Descriptions
31:6
Reserved
Must be kept at reset value
5
RFD1
Receive FIFO1 dequeue
This bit is set by the software to start dequeuing a frame from receive FIFO1.
This bit is reset by the hardware while the dequeuing is done.
4
RFO1
Receive FIFO1 overfull
0: The receive FIFO1 is not overfull
1: The receive FIFO1 is overfull
3
RFF1
Receive FIFO1 full
0: The receive FIFO1 is not full
1: The receive FIFO1 is full
2
Reserved
Must be kept at reset value
1:0
RFL1[1:0]
Receive FIFO1 length
These bits are the length of the receive FIFO1.
25.4.6. Interrupt enable register (CAN_INTEN)
Address offset: 0x14
Reset value: 0x0000 0000
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This register has to be accessed by word(32-bit).
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
SLPWIE
WIE
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
ERRIE
Reserved
ERRNIE
BOIE
PERRIE
WERRI
E
Reserve
d
RFOIE1
RFFIE1
RFNEIE
1
RFOIE0
RFFIE0
RFNEIE
0
TMEIE
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31:18
Reserved
Must be kept at reset value
17
SLPWIE
Sleep working interrupt enable
0: Sleep working interrupt disable
1: Sleep working interrupt enable
16
WIE
Wakeup interrupt enable
0: Wakeup interrupt disable
1: Wakeup interrupt enable
15
ERRIE
Error interrupt enable
0: Error interrupt disable
1: Error interrupt enable
14:12
Reserved
Must be kept at reset value
11
ERRNIE
Error number interrupt enable
0: Error number interrupt disable
1: Error number interrupt enable
10
BOIE
Bus-off interrupt enable
0: Bus-off interrupt disable
1: Bus-off interrupt enable
9
PERRIE
Passive error interrupt enable
0: Passive error interrupt disable
1: Passive error interrupt enable
8
WERRIE
Warning error interrupt enable
0: Warning error interrupt disable
1: Warning error interrupt enable
7
Reserved
Must be kept at reset value
6
RFOIE1
Receive FIFO1 overfull interrupt enable
0: Receive FIFO1 overfull interrupt disable
1: Receive FIFO1 overfull interrupt enable
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5
RFFIE1
Receive FIFO1 full interrupt enable
0: Receive FIFO1 full interrupt disable
1: Receive FIFO1 full interrupt enable
4
RFNEIE1
Receive FIFO1 not empty interrupt enable
0: Receive FIFO1 not empty interrupt disable
1: Receive FIFO1 not empty interrupt enable
3
RFOIE0
Receive FIFO0 overfull interrupt enable
0: Receive FIFO0 overfull interrupt disable
1: Receive FIFO0 overfull interrupt enable
2
RFFIE0
Receive FIFO0 full interrupt enable
0: Receive FIFO0 full interrupt disable
1: Receive FIFO0 full interrupt enable
1
RFNEIE0
Receive FIFO0 not empty interrupt enable
0: Receive FIFO0 not empty interrupt disable
1: Receive FIFO0 not empty interrupt enable
0
TMEIE
Transmit mailbox empty interrupt enable
0: Transmit mailbox empty interrupt disable
1: Transmit mailbox empty interrupt enable
25.4.7. Error register (CAN_ERR)
Address offset: 0x18
Reset value: 0x0000 0000
This register has to be accessed by word(32-bit).
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RECNT[7:0]
TECNT[7:0]
r
r
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
ERRN[2:0]
Reserved
BOERR
PERR
WERR
rw
r
r
r
Bits
Fields
Descriptions
31:24
RECNT[7:0]
Receive Error Count
23:16
TECNT[7:0]
Transmit Error Count
15:7
Reserved
Must be kept at reset value
6:4
ERRN[2:0]
Error number
These bits indicate the error status of bit transformation. They are updated by the
hardware. While the bit transformation is successful, they are equal to 0. Software
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can set these bits to 0b111.
000: No Error
001: Stuff Error
010: Form Error
011: Acknowledgment Error
100: Bit recessive Error
101: Bit dominant Error
110: CRC Error
111: Set by software
3
Reserved
Must be kept at reset value
2
BOERR
Bus-off error
Whenever the CAN enters buf-off state, the bit will be set by the hardware.
1
PERR
Passive error
Whenever the TECNT or RECNT is greater than 127, the bit will be set by the
hardware.
0
WERR
Warning error
Whenever the TECNT or RECNT is greater than or equal to 96, the bit will be set by
the hardware.
25.4.8. Bit timing register (CAN_BT)
Address offset: 0x1C
Reset value: 0x0123 0000
This register has to be accessed by word(32-bit).
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
SCMOD
LCMOD
Reserved
SJW[1:0]
Reserved
BS2[2:0]
BS1[3:0]
rw
rw
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
BAUDPSC[9:0]
rw
Bits
Fields
Descriptions
31
SCMOD
Silent communication mode
0: Silent communication disable
1: Silent communication enable
30
LCMOD
Loopback communication mode
0: Loopback communication disable
1: Loopback communication enable
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29:26
Reserved
Must be kept at reset value
25:24
SJW[1:0]
Resynchronization jump width
Resynchronization jump width time quantum= SJW[1:0]+1
23
Reserved
Must be kept at reset value
22:20
BS2[2:0]
Bit segment 2
Bit segment 2 time quantum=BS2[2:0]+1
19:16
BS1[3:0]
Bit segment 1
Bit segment 1 time quantum=BS1[3:0]+1
15:10
Reserved
Must be kept at reset value
9:0
BAUDPSC[9:0]
Baud rate prescaler
The CAN baud rate prescaler
25.4.9. Transmit mailbox identifier register (CAN_TMIx) (x=0..2)
Address offset: 0x180, 0x190, 0x1A0
Reset value: 0xXXXX XXXX (bit0=0)
This register has to be accessed by word(32-bit).
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
SFID[10:0]/EFID[28:18]
EFID[17:13]
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
EFID[12:0]
FF
FT
TEN
rw
rw
rw
rw
Bits
Fields
Descriptions
31:21
SFID[10:0]/EFID[28:18]
The frame identifier
SFID[10:0]: Standard format frame identifier
EFID[28:18]: Extended format frame identifier
20:16
EFID[17:13]
The frame identifier
EFID[17:13]: Extended format frame identifier
15:3
EFID[12:0]
The frame identifier
EFID[12:0]: Extended format frame identifier
2
FF
Frame format
0: Standard format frame
1: Extended format frame
1
FT
Frame type
0: Data frame
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1: Remote frame
0
TEN
Transmit enable
0: Transmit disable
1: Transmit enable
This bit is set by the software when one frame will be transmitted and reset by
the hardware when the transmit mailbox is empty.
25.4.10. Transmit mailbox property register (CAN_TMPx) (x=0..2)
Address offset: 0x184, 0x194, 0x1A4
Reset value: 0xXXXX XXXX
This register has to be accessed by word(32-bit).
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
TS[15:0]
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
TSEN
Reserved
DLENC[3:0]
rw
rw
Bits
Fields
Descriptions
31:16
TS[15:0]
Time stamp
The time stamp of frame in transmit mailbox.
15:9
Reserved
Must be kept at reset value
8
TSEN
Time stamp enable
0: Time stamp disable
1: Time stamp enable. The TS[15:0] will be transmitted in the DATA6 and DATA7 in
DL.
This bit is available while the TTC bit in CAN_CTL is set.
7:4
Reserved
Must be kept at reset value
3:0
DLENC[3:0]
Data length code
DLENC[3:0] is the number of bytes in a frame.
25.4.11. Transmit mailbox data0 register (CAN_TMDATA0x) (x=0..2)
Address offset: 0x188, 0x198, 0x1A8
Reset value: 0xXXXX XXXX
This register has to be accessed by word(32-bit).
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31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
DB3[7:0]
DB2[7:0]
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
DB1[7:0]
DB0[7:0]
rw
rw
Bits
Fields
Descriptions
31:24
DB3[7:0]
Data byte 3
23:16
DB2[7:0]
Data byte 2
15:8
DB1[7:0]
Data byte 1
7:0
DB0[7:0]
Data byte 0
25.4.12. Transmit mailbox data1 register (CAN_TMDATA1x) (x=0..2)
Address offset: 0x18C, 0x19C, 0x1AC
Reset value: 0xXXXX XXXX
This register has to be accessed by word(32-bit).
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
DB7[7:0]
DB6[7:0]
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
DB5[7:0]
DB4[7:0]
rw
rw
Bits
Fields
Descriptions
31:24
DB7[7:0]
Data byte 7
23:16
DB6[7:0]
Data byte 6
15:8
DB5[7:0]
Data byte 5
7:0
DB4[7:0]
Data byte 4
25.4.13. Receive FIFO mailbox identifier register (CAN_RFIFOMIx) (x=0..1)
Address offset: 0x1B0, 0x1C0
Reset value: 0xXXXX XXXX
This register has to be accessed by word(32-bit).
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31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
SFID[10:0]/EFID[28:18]
EFID[17:13]
r
r
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
EFID[12:0]
FF
FT
Reserved
r
r
r
Bits
Fields
Descriptions
31:21
SFID[10:0]/EFID[28:18]
The frame identifier
SFID[10:0]: Standard format frame identifier
EFID[28:18]: Extended format frame identifier
20:16
EFID[17:13]
The frame identifier
EFID[17:13]: Extended format frame identifier
15:3
EFID[12:0]
The frame identifier
EFID[12:0]: Extended format frame identifier
2
FF
Frame format
0: Standard format frame
1: Extended format frame
1
FT
Frame type
0: Data frame
1: Remote frame
0
Reserved
Must be kept at reset value
25.4.14. Receive FIFO mailbox property register (CAN_RFIFOMPx) (x=0..1)
Address offset: 0x1B4, 0x1C4
Reset value: 0xXXXX XXXX
This register has to be accessed by word(32-bit).
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
TS[15:0]
r
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
FI[7:0]
Reserved
DLENC[3:0]
r
r
Bits
Fields
Descriptions
31:16
TS[15:0]
Time stamp
The time stamp of frame in transmit mailbox.
GD32F1x0 User Manual
661
15:8
FI[7:0]
Filtering index
The index of the filter by which the frame is passed.
7:4
Reserved
Must be kept at reset value
3:0
DLENC[3:0]
Data length code
DLENC[3:0] is the number of bytes in a frame.
25.4.15. Receive FIFO mailbox data0 register (CAN_RFIFOMDATA0x) (x=0..1)
Address offset: 0x1B8, 0x1C8
Reset value: 0xXXXX XXXX
This register has to be accessed by word(32-bit).
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
DB3[7:0]
DB2[7:0]
r
r
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
DB1[7:0]
DB0[7:0]
r
r
Bits
Fields
Descriptions
31:24
DB3[7:0]
Data byte 3
23:16
DB2[7:0]
Data byte 2
15:8
DB1[7:0]
Data byte 1
7:0
DB0[7:0]
Data byte 0
25.4.16. Receive FIFO mailbox data1 register (CAN_RFIFOMDATA1x) (x=0..1)
Address offset: 0x1BC, 0x1CC
Reset value: 0xXXXX XXXX
This register has to be accessed by word(32-bit).
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
DB7[7:0]
DB6[7:0]
r
r
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
DB5[7:0]
DB4[7:0]
r
r
Bits
Fields
Descriptions
GD32F1x0 User Manual
662
31:24
DB7[7:0]
Data byte 7
23:16
DB6[7:0]
Data byte 6
15:8
DB5[7:0]
Data byte 5
7:0
DB4[7:0]
Data byte 4
25.4.17. Filter control register (CAN_FCTL)
Address offset: 0x200
Reset value: 0x2A1C 0E01
This register has to be accessed by word(32-bit).
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
HBC1F[5:0]
Reserved
FLD
rw
rw
Bits
Fields
Descriptions
31:14
Reserved
Must be kept at reset value
13:8
HBC1F[5:0]
Header bank of CAN1 filter
7:1
Reserved
Must be kept at reset value
0
FLD
Filter lock disable
0: Filter lock enable
1: Filter lock disable
25.4.18. Filter mode configuration register (CAN_FMCFG)
Address offset: 0x204
Reset value: 0x0000 0000
This register has to be accessed by word(32-bit).
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
FMOD2
7
FMOD2
6
FMOD2
5
FMOD2
4
FMOD2
3
FMOD2
2
FMOD2
1
FMOD2
0
FMOD1
9
FMOD1
8
FMOD1
7
FMOD1
6
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
FMOD1
5
FMOD1
4
FMOD1
3
FMOD1
2
FMOD1
1
FMOD1
0
FMOD9
FMOD8
FMOD7
FMOD6
FMOD5
FMOD4
FMOD3
FMOD2
FMOD1
FMOD0
GD32F1x0 User Manual
663
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31:28
Reserved
Must be kept at reset value
27:0
FMODx
Filter mode
0: Filter x with Mask mode
1: Filter x with List mode
25.4.19. Filter scale configuration register (CAN_FSCFG)
Address offset: 0x20C
Reset value: 0x0000 0000
This register has to be accessed by word(32-bit).
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
FS27
FS26
FS25
FS24
FS23
FS22
FS21
FS20
FS19
FS18
FS17
FS16
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
FS15
FS14
FS13
FS12
FS11
FS10
FS9
FS8
FS7
FS6
FS5
FS4
FS3
FS2
FS1
FS0
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31:28
Reserved
Must be kept at reset value
27:0
FSx
Filter scale
0: Filter x with 16-bit scale
1: Filter x with 32-bit scale
25.4.20. Filter associated FIFO register (CAN_FAFIFO)
Address offset: 0x214
Reset value: 0x0000 0000
This register has to be accessed by word(32-bit).
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
FAF27
FAF26
FAF25
FAF24
FAF23
FAF22
FAF21
FAF20
FAF19
FAF18
FAF17
FAF16
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
FAF15
FAF14
FAF13
FAF12
FAF11
FAF10
FAF9
FAF8
FAF7
FAF6
FAF5
FAF4
FAF3
FAF2
FAF1
FAF0
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
GD32F1x0 User Manual
664
Bits
Fields
Descriptions
31:28
Reserved
Must be kept at reset value
27:0
FAFx
Filter associated FIFO
0: Filter x associated with FIFO0
1: Filter x associated with FIFO1
25.4.21. Filter working register (CAN_FW)
Address offset: 0x21C
Reset value: 0x0000 0000
This register has to be accessed by word(32-bit).
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
FW2
7
FW2
6
FW2
5
FW2
4
FW2
3
FW2
2
FW2
1
FW2
0
FW1
9
FW1
8
FW1
7
FW1
6
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
FW1
5
FW1
4
FW1
3
FW1
2
FW1
1
FW1
0
FW9
FW8
FW7
FW6
FW5
FW4
FW3
FW2
FW1
FW0
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
Bits
Fields
Descriptions
31:28
Reserved
Must be kept at reset value
27:0
FWx
Filter working
0: Filter x working disable
1: Filter x working enable
25.4.22. Filter x data y register (CAN_FxDATAy) (x=0..27, y=0..1)
Address offset: 0x240+8*x+4*y, (x=0..27,y=0,1)
Reset value: 0xXXXX XXXX
This register has to be accessed by word(32-bit).
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
FD31
FD30
FD29
FD28
FD27
FD26
FD25
FD24
FD23
FD22
FD21
FD20
FD19
FD18
FD17
FD16
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
FD15
FD14
FD13
FD12
FD11
FD10
FD9
FD8
FD7
FD6
FD5
FD4
FD3
FD2
FD1
FD0
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
GD32F1x0 User Manual
665
Bits
Fields
Descriptions
31:0
FDx
Filter data
Mask mode
0: Mask match disable
1: Mask match enable
List mode
0: List identifier bit is 0
1: List identifier bit is 1
25.4.23. PHY control register (CAN_PHYCTL)
Address offset: 0x3FC
Reset value: 0x0000 0300
This register has to be accessed by word(32-bit).
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
POMOD
Reserved
PHYEN
rw
rw
Bits
Fields
Descriptions
31:10
Reserved
Must be kept at reset value
9:8
POMOD
CAN PHY output driver control register
This bit set and cleared by software.
00: Low Slope Mode
01: Middle Slope Mode
10: High Slope Mode
11: High Speed Mode(Default)
7:1
Reserved
Must be kept at reset value
0
PHYEN
PHY enable bit
This bit set and cleared by software. This bit can use CAN PHY for CAN0 or not.
0: No CAN PHY mode
1: CAN PHY enable for CAN0
GD32F1x0 User Manual
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26. Revision history
Table 26-1. Revision history
Revision No.
Description
Date
1.0
Initial Release
Mar.18, 2014
2.0
Add GD32F170/190 Products
Jan.15, 2016
3.0
Adapt To New Name Convention
Jun.24, 2016

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