J Link / Trace User Guide (UM08001) 02 Jlink

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J-Link / J-Trace
User Guide

Software Version V5.00
Manual Rev. 0
Date: June 8, 2015

Document: UM08001

A product of SEGGER Microcontroller GmbH & Co. KG
www.segger.com

2

Disclaimer
Specifications written in this document are believed to be accurate, but are not guaranteed to be entirely free of error. The information in this manual is subject to
change for functional or performance improvements without notice. Please make sure
your manual is the latest edition. While the information herein is assumed to be
accurate, SEGGER Microcontroller GmbH & Co. KG (the manufacturer) assumes no
responsibility for any errors or omissions. The manufacturer makes and you receive
no warranties or conditions, express, implied, statutory or in any communication with
you. The manufacturer specifically disclaims any implied warranty of merchantability
or fitness for a particular purpose.

Copyright notice
You may not extract portions of this manual or modify the PDF file in any way without
the prior written permission of the manufacturer. The software described in this document is furnished under a license and may only be used or copied in accordance
with the terms of such a license.
© 2015 SEGGER Microcontroller GmbH & Co. KG, Hilden / Germany

Trademarks
Names mentioned in this manual may be trademarks of their respective companies.
Brand and product names are trademarks or registered trademarks of their respective holders.

Contact address
SEGGER Microcontroller GmbH & Co. KG
In den Weiden 11
D-40721 Hilden
Germany
Tel.+49 2103-2878-0
Fax.+49 2103-2878-28
Email: support@segger.com
Internet: http://www.segger.com

Revisions
This manual describes the J-Link and J-Trace device.
For further information on topics or routines not yet specified, please contact us.
Revision

Date

By

V5.00 Rev. 0

150520

EL

V4.99b Rev. 0

150520

EL

V4.99a Rev. 0

150429

AG

V4.98d Rev. 0

150427

EL

V4.98b Rev. 0

150410

AG

J-Link / J-Trace (UM08001)

Explanation
Chapter "J-Flash SPI"
* Initial version added
Chapter "Related Software"
* Section "J-Link STM32 Unlock"
- Added command line options
Chapter "Target interfaces and Adapters"
Chapter "20-pin J-Link connector", section
"Pinout for SPI" added.
Chapter "Related Software"
* Section "Configure SWO output after device
reset" updated.
Chapter "Licensing"
* Section "J-Trace for Cortex-M" updated.

© 2004-2014 SEGGER Microcontroller GmbH & Co. KG

3

Revision

Date

By

V4.98 Rev. 0

150320

NG

V4.96f Rev. 0

150204

JL

V4.96 Rev. 0

141219

JL

V4.90d Rev. 0

141112

NG

V4.90c Rev. 0

140924

JL

V4.90b Rev. 1

140813

EL

V4.90b Rev. 0

140813

NG

V4.86 Rev. 2

140606

AG

V4.86 Rev. 1

140527

JL

V4.86 Rev. 0

140519

AG

V4.84 Rev. 0

140321

EL

V4.82 Rev. 1

140228

EL

V4.82 Rev. 0

140218

JL

J-Link / J-Trace (UM08001)

Explanation
Chapter "Related Software"
* Section "J-Link Commander"
Sub-Section "Commands" added.
Chapter "Working with J-Link and J-Trace"
* Section "J-Link script files" updated
Chapter "Related Software"
* Section "GDB Server"
Exit code description added.
Chapter "RTT" added.
Chapter "Related Software"
* Section "GDB Server"
Command line option "-strict" added.
Command line option "-timeout" added.
Chapter "Related Software"
* Section "J-Link Remote Server" updated.
* Section "J-Scope" updated.
Chapter "Related Software"
* Section "JTAGLoad" updated.
Chapter "Working with J-Link and J-Trace"
* Section "Connecting multiple J-Links / J-Traces
to your PC" updated
Chapter "J-Link software"
* Section "J-Link Configurator" updated.
Chapter "Related Software"
* Section "J-Scope" added.
Chapter "Device specifics"
* Section "Silicon Labs - EFM32 series devices"
added
Chapter "Related Software"
* Section "GDB Server"
Command line options -halt / -nohalt added.
Description for GDB Server CL version added.
Chapter "Flash download"
Section "Mentor Sourcery CodeBench" added.
Chapter "Working with J-Link"
* Section "Virtual COM Port (VCOM) improved.
Chapter "Target interfaces and adapters"
* Section "Pinout for SWD + Virtual COM Port
(VCOM) added."
Chapter "Related Software"
* Section "Command line options"
Extended command line option -speed.
Chapter "J-Link software and documentation
package"
* Section "J-Link STR91x Commander"
Added command line option parameter to
specify a customized scan-chain.
Chapter "Working with J-Link"
* Section "Virtual COM Port (VCOM) added.
Chapter "Setup"
* Section "Getting started with J-Link and DS-5"
Chapter "Related Software"
* Section "GDB Server"
Command line option -notimout added.

© 2004-2014 SEGGER Microcontroller GmbH & Co. KG

4

Revision

Date

By

V4.80f Rev. 0

140204

JL

V4.80 Rev. 1

131219

JL/
NG

V4.80 Rev. 0

131105

JL

V4.76 Rev. 3

130823

JL

V4.76 Rev. 2

130821

JL

V4.76 Rev. 1

130819

JL

V4.76 Rev. 0

130809

JL

V4.71b Rev. 0

130507

JL

V4.66 Rev. 0

130221

JL

V4.62b Rev. 0

130219

EL

V4.62 Rev. 0

130129

JL

V4.62 Rev. 0

130124

EL

V4.58 Rev. 1

121206

AG

V4.58 Rev. 0

121126

JL

V4.56b Rev. 0

121112

JL

V4.56a Rev. 0

121106

JL

J-Link / J-Trace (UM08001)

Explanation
Chapter "Related Software"
* Section "GDB Server"
Command line options and remote commands
added.
Chapter "Related Software"
* Section "GDB Server"
Remote commands and command line options
description improved.
Several corrections.
Chapter "Related Software"
* Section "GDB Server"
SEGGER-specific GDB protocol extensions
added.
Chapter "Flash Download"
* Replaced references to GDB Server manual.
Chapter "Working withc J-Link"
* Replaced references to GDB Server manual.
Chapter "Related Software"
* Section "GDB Server"
Remote commands added.
Chapter "Related Software"
* Section "SWO Viewer"
Sample code updated.
Chapter "Related Software"
* Sections reordered and updated.
Chapter "Setup"
* Section "Using JLinkARM.dll moved here.
Chapter "Related Software"
* Section "SWO Viewer"
Added new command line options.
Chapter "Introduction"
* Section "Supported OS"
Added Linux and Mac OSX
Chapter "Introduction"
* Section "J-Link / J-Trace models"
Clock rise and fall times updated.
Chapter "Introduction"
* Section "J-Link / J-Trace models"
Sub-section "J-link ULTRA" updated.
Chapter "Target interfaces and adapters"
* Section "9-pin JTAG/SWD connector"
Pinout description corrected.
Chapter "Intoduction"
* Section "J-Link / J-Trace models" updated.
Chapter "Working with J-Link"
* Section "J-Link script files"
Sub-section "Executing J-Link script files"
updated.
Chapter "Related Software"
* Section "J-Link SWO Viewer"
Added sub-section "Configure SWO output
after device reset"
Chapter "Related Software"
* Section "J-Link Commander"
Renamed "Commander script files" to
"Commander files" and "script mode" to
"batch mode".
© 2004-2014 SEGGER Microcontroller GmbH & Co. KG

5

Revision

Date

By

V4.56 Rev. 0

121022

AG

V4.54 Rev. 1

121009

JL

V4.54 Rev. 0

120913

EL

V4.53c Rev. 0

120904

EL

V4.51h Rev. 0

120717

EL

V4.51e Rev. 1

120704

EL

V4.51e Rev. 0

120704

AG

V4.51b Rev. 0

120611

EL

V4.51a Rev. 0

120606

EL

V4.47a Rev. 0

120419

AG

V4.46 Rev. 0

120416

EL

V4.42 Rev. 0

120214

EL

V4.36 Rev. 1

110927

EL

V4.36 Rev. 0

110909

AG

V4.26 Rev. 1

110513

KN

V4.26 Rev. 0

110427

KN

V4.24 Rev. 1

110228

AG

J-Link / J-Trace (UM08001)

Explanation
Renamed "J-Link TCP/IP Server" to "J-Link Remote
Server".
Chapter "Related Software"
* Section "TCP/IP Server", subsection "Tunneling
Mode" added.
Chapter "Flash Breakpoints"
* Section "Licensing" updated.
Chapter "Device specifics"
* Section "Freescale", subsection "Data flash
support" added.
Chapter "Licensing"
* Section "Device-based license" updated.
Chapter "Flash download"
* Section "J-Link commander" updated.
Chapter "Support and FAQs"
* Section "Frequently asked questions" updated.
Chapter "J-Link and J-Trace related software"
* Section "J-Link Commander" updated.
Chapter "Working with J-Link"
* Section "Reset strategies" updated and
corrected. Added reset type 8.
Chapter "Device specifics"
* Section "ST" updated and corrected.
Chapter "J-Link and J-Trace related software"
* Section "SWO Viewer" added.
Chapter "Device specifics"
* Section "ST", subsection "ETM init"
for some STM32 devices added..
* Section "Texas Instruments" updated.
Chapter "Target interfaces and adapters"
* Section "Pinout for SWD" updated.
Chapter "Device specifics"
* Section "Texas Instruments" updated.
Chapter "Support" updated.
Chapter "Working with J-Link"
* Section "J-Link script files" updated.
Chapter "Flash download" added.
Chapter "Flash breakpoints" added.
Chapter "Target interfaces and adapters"
* Section "20-pin JTAG/SWD connector" updated.
Chapter "RDI" added.
Chapter "Setup" updated.
Chapter "Device specifics" updated.
Chapter "Working with J-Link"
* Section "J-Link script files" updated.
Chapter "Introduction"
* Section "J-Link / J-Trace models" corrected.
Several corrections.
Chapter "Introduction"
* Section "J-Link / J-Trace models" corrected.
Chapter "Device specifics"
* Section "ST Microelectronics" updated.

© 2004-2014 SEGGER Microcontroller GmbH & Co. KG

6

Revision

Date

By

V4.24 Rev. 0

110216

AG

V4.23d

110202

AG

V4.21g

101130

AG

V4.21

101025

AG

V4.20j

101019

AG

V4.20b

100923

AG

90

100818

AG

89

100630

AG

88

100622

AG

87

100617

AG

86

100504

AG

85

100428

AG

84

100324

KN

83

100223

KN

82

100215

AG

81

100202

KN

J-Link / J-Trace (UM08001)

Explanation
Chapter "Device specifics"
* Section "Samsung" added.
Chapter "Working with J-Link"
* Section "Reset strategies" updated.
Chapter "Target interfaces and adapters"
* Section "9-pin JTAG/SWD connector" added.
Chapter "J-Link and J-Trace related software"
* Section "J-Link software and documentation
package in detail" updated.
Chapter "Introduction"
* Section "Built-in intelligence for
supported CPU-cores" added.
Chapter "Working with J-Link"
* Section "Reset strategies" updated.
Chapter "Device specifics"
* Section "Freescale" updated.
Chapter "Flash download and flash breakpoints
* Section "Supported devices" updated
* Section "Setup for different debuggers
(CFI flash)" updated.
Chapter "Device specifics"
* Section "Freescale" updated.
Chapter "Working with J-Link"
* Section "Reset strategies" updated.
Chapter "Working with J-Link"
* Section "Reset strategies" updated.
Chapter "Working with J-Link"
* Section "J-Link script files" updated.
* Section "Command strings" upadted.
Chapter "Target interfaces and adapters"
* Section "19-pin JTAG/SWD and Trace
connector" corrected.
Chapter "Setup"
* Section "J-Link configurator added."
Several corrections.
Chapter "J-Link and J-Trace related software"
* Section "SWO Analyzer" added.
Several corrections.
Chapter "Introduction"
* Section "J-Link / J-Trace models" updated.
Chapter "Target interfaces and adapters"
* Section "Adapters" updated.
Chapter "Introduction"
* Section "J-Link / J-Trace models" updated.
Chapter "Working with J-Link and J-Trace"
* Several corrections
Chapter Flash download & flash breakpoints
* Section "Supported devices" updated
Chapter "Introduction"
* Section "J-Link / J-Trace models" updated.
Chapter "Working with J-Link"
* Section "J-Link script files" added.
Chapter "Device Specifics"
* Section "Luminary Micro" updated.
Chapter "Flash download and flash breakpoints"
* Section "Supported devices" updated.

© 2004-2014 SEGGER Microcontroller GmbH & Co. KG

7

Revision

Date

By

80

100104

KN

79

091201

AG

78

091023

AG

77

090910

AG

76

090828

KN

75

090729

AG

74

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KN

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090701

KN

72

090618

AG

71

090616

AG

70

090605

AG

69

090515

AG

J-Link / J-Trace (UM08001)

Explanation
Chapter "Flash download and flash breakpoints
* Section "Supported devices" updated
Chapter "Working with J-Link and J-Trace"
* Section "Reset strategies" updated.
Chapter "Licensing"
* Section "J-Link OEM versions" updated.
Chapter "Licensing"
* Section "J-Link OEM versions" updated.
Chapter "Introduction"
* Section "J-Link / J-Trace models" updated.
Chapter "Introduction"
* Section" Specifications" updated
* Section "Hardware versions" updated
* Section "Common features of the J-Link product
family" updated
Chapter "Target interfaces and adapters"
* Section "5 Volt adapter" updated
Chapter "Introduction"
* Section "J-Link / J-Trace models" updated.
Chapter "Working with J-Link and J-Trace"
* Section "SWD interface" updated.
Chapter "Introduction"
* Section "Supported IDEs" added
* Section "Supported CPU cores" updated
* Section "Model comparison chart" renamed to
"Model comparison"
* Section "J-Link bundle comparison chart"
removed
Chapter "Introduction"
* Section "J-Link and J-Trace models" added
* Sections "Model comparison chart" &
"J-Link bundle comparison chart"added
Chapter "J-Link and J-Trace models" removed
Chapter "Hardware" renamed to
"Target interfaces & adapters"
* Section "JTAG Isolator" added
Chapter "Target interfaces and adapters"
* Section "Target board design" updated
Several corrections
Chapter "Working with J-Link"
* Section "J-Link control panel" updated.
Chapter "Flash download and flash breakpoints"
* Section "Supported devices" updated.
Chapter "Device specifics"
* Section "NXP" updated.
Chapter "Device specifics"
* Section "NXP" updated.
Chapter "Introduction"
* Section "Common features of the J-Link
product family" updated.
Chapter "Working with J-Link"
* Section "Reset strategies" updated.
* Section "Indicators" updated.
Chapter "Flash download and flash breakpoints"
* Section "Supported devices" updated.

© 2004-2014 SEGGER Microcontroller GmbH & Co. KG

8

Revision

Date

By

68

090428

AG

67

090402

AG

66

090327

AG

65

090320

AG

64

090313

AG

63

090212

AG

62

090211

AG

61

090120

TQ

60

090114

AG

59

090108

KN

58

090105

AG

57

081222

AG

56

081219

AG

55

081218

AG

54

081217

AG

53

081216

AG

52

081212

AG

51

081202

KN

J-Link / J-Trace (UM08001)

Explanation
Chapter "J-Link and J-Trace related software"
* Section "J-Link STM32 Commander" added.
Chapter "Working with J-Link"
* Section "Reset strategies" updated.
Chapter "Working with J-Link"
* Section "Reset strategies" updated.
Chapter "Background information"
* Section "Embedded Trace Macrocell (ETM)"
updated.
Chapter "J-Link and J-Trace related software"
* Section "Dedicated flash programming
utilities for J-Link" updated.
Several changes in the manual structure.
Chapter "Working with J-Link"
* Section "Indicators" added.
Chapter "Hardware"
* Several corrections.
* Section "Hardware Versions" Version 8.0 added.
Chapter "Working with J-Link and J-Trace"
* Section "Reset strategies" updated.
Chapter J-Link and J-Trace related software
* Section "J-Link STR91x Commander
(Command line tool)" updated.
Chapter "Device specifics"
* Section "ST Microelectronics" updated.
Chapter "Hardware" updated.
Chapter "Working with J-Link"
* Section "Cortex-M3 specific reset strategies"
Chapter "Working with J-Link"
* Section "Cortex-M3 specific reset strategies"
Chapter Hardware
* Section "Target board design for JTAG"
updated.
* Section "Target board design for SWD" added.
Chapter "Working with J-Link Pro"
* Section "Connecting J-Link Pro the first time"
updated.
Chapter "Working with J-Link Pro"
* Section "Introduction" updated.
* Section "Configuring J-Link Pro
via web interface" updated.
Chapter "Introduction"
* Section "J-Link Pro overview" updated.
Chapter "Working with J-Link Pro"
* Section "FAQs" added.
Chapter "Support and FAQs"
* Section "Frequently Asked Questions" updated.
Chapter "Hardware" updated.
Chapter "Working with J-Link and J-Trace"
* Section "Command strings" updated.
Chapter "Working with J-Link Pro" updated.
Chapter "Working with J-Link Pro" added.
Chapter "Licensing"
* Section "Original SEGGER products" updated.
Several corrections.

© 2004-2014 SEGGER Microcontroller GmbH & Co. KG

9

Revision

Date

By

50

081030

AG

49

081029

AG

48

080916

AG

47

080910

AG

46

080904

AG

45

080902

AG

44

080827

AG

43

080826

AG

42

080820

AG

41

080811

AG

40

080630

AG

39

080627

AG

38

080618

AG

37

080617

AG

36

080530

AG

35

080215

AG

J-Link / J-Trace (UM08001)

Explanation
Chapter "Flash download and flash breakpoints"
* Section "Supported devices" corrected.
Several corrections.
Chapter "Working with J-Link and J-Trace"
* Section "Connecting multiple J-Links /
J-Traces to your PC" updated.
Chapter "Licensing" updated.
Chapter "Licensing" added.
Chapter "Hardware"
Section "J-Link OEM versions" moved to chapter
"Licensing"
Chapter "Hardware"
Section "JTAG+Trace connector" JTAG+Trace
connector pinout corrected.
Section "J-Link OEM versions" updated.
Chapter "J-Link control panel" moved to chapter
"Working with J-Link".
Several corrections.
Chapter "Flash download and flash breakpoints"
Section "Supported devices" updated.
Chapter "Flash download and flash breakpoints"
Section "Supported devices" updated.
Chapter "Flash download and flash breakpoints"
updated.
Chapter "Flash download and flash breakpoints",
section "Supported devices" updated.
Chapter "Flash download and flash breakpoints"
updated.
Chapter "J-Link status window" renamed to "J-Link
control panel"
Various corrections.
Chapter "Flash download and flash breakpoints"
Section "Licensing" updated.
Section "Using flash download and flash
breakpoints with different debuggers" updated.
Chapter "J-Link status window" added.
Chapter "Support and FAQs"
Section "Frequently Asked Questions" updated
Chapter "Reset strategies"
Section "Cortex-M3 specific reset strategies"
updated.
Chapter "Reset strategies"
Section "Cortex-M3 specific reset strategies"
updated.
Chapter "Hardware"
Section "Differences between different versions"
updated.
Chapter "Working with J-Link and J-Trace"
Section "Cortex-M3 specific reset strategies"
added.
Chapter "J-Link and J-Trace related software"
Section "J-Link software and documentation
package in detail" updated.

© 2004-2014 SEGGER Microcontroller GmbH & Co. KG

10

Revision

Date

By

34

080212

AG

33

080207

AG

32

0080129

SK

31

0080103

SK

30

071211

AG

29

070912

SK

28

070912

SK

28

070912

AG

27

070827

TQ

26

070710

SK

25

070516

SK

J-Link / J-Trace (UM08001)

Explanation
Chapter "J-Link and J-Trace related software"
Section "J-Link TCP/IP Server (Remote J-Link /
J-Trace use)" updated.
Chapter "Working with J-Link and J-Trace"
Section "Command strings" updated.
Chapter "Flash download and flash breakpoints"
Section "Introduction" updated.
Section "Licensing" updated.
Section "Using flash download and flash
breakpoints with different debuggers" updated.
Chapter "Flash download and flash breakpoints"
added
Chapter "Device specifics:"
Section "ATMEL - AT91SAM7 - Recommended init
sequence" added.
Chapter "Device specifics":
Section "NXP - LPC - Fast GPIO bug" list of
device enhanced.
Chapter "Device specifics":
Section "NXP - LPC - Fast GPIO bug" updated.
Chapter "Device specifics":
Section "Analog Devices" updated.
Section "ATMEL" updated.
Section "Freescale" added.
Section "Luminary Micro" added.
Section "NXP" updated.
Section "OKI" added.
Section "ST Microelectronics" updated.
Section "Texas Instruments" updated.
Chapter "Related software":
Section "J-Link STR91x Commander" updated
Chapter "Hardware", section "Target board design"
updated.
Chapter "Related software":
Section "J-LinkSTR91x Commander" added.
Chapter "Device specifics":
Section "ST Microelectronics" added.
Section "Texas Instruments" added.
Subsection "AT91SAM9" added.
Chapter "Working with J-Link/J-Trace":
Section "Command strings" updated.
Chapter "Working with J-Link/J-Trace":
Section "Command strings" updated.
Chapter "Introduction":
Section "Features of J-Link" updated.
Chapter "Background Information":
Section "Embedded Trace Macrocell" added.
Section "Embedded Trace Buffer" added.
Chapter "Working with J-Link/J-Trace":
Section "Reset strategies in detail"
- "Software, for Analog Devices ADuC7xxx
MCUs" updated
- "Software, for ATMEL AT91SAM7 MCUs"
added.
Chapter "Device specifics"
Section "Analog Devices" added.
Section "ATMEL" added.

© 2004-2014 SEGGER Microcontroller GmbH & Co. KG

11

Revision

Date

By

24

070323

SK

23

070320

SK

22

070316

SK

21

070312

SK

20

070307

SK

19

070226

SK

18

070221

SK

17

070131

SK

16

061222

SK

15

060914

OO

14

060818

TQ

13

060711

OO

12

060628

OO

11

060607

SK

10

060526

SK

9

060324

OO

8

060117

OO

7

051208

OO

J-Link / J-Trace (UM08001)

Explanation
Chapter "Setup":
"Uninstalling the J-Link driver" updated.
"Supported ARM cores" updated.
Chapter "Hardware":
"Using the JTAG connector with SWD" updated.
Chapter "Hardware":
"Using the JTAG connector with SWD" added.
Chapter "Hardware":
"Differences between different versions"
supplemented.
Chapter "J-Link / J-Trace related software":
"J-Link GDB Server" licensing updated.
Chapter "J-Link / J-Trace related software" updated
and reorganized.
Chapter "Hardware"
"List of OEM products" updated
Chapter "Device specifics" added
Subchapter "Command strings" added
Chapter "Hardware":
"Version 5.3": Current limits added
"Version 5.4" added
Chapter "Setup":
"Installating the J-Link USB driver" removed.
"Installing the J-Link software and documentation
pack" added.
Subchapter "List of OEM products" updated.
"OS support" updated
Chapter "Preface": "Company description" added.
J-Link picture changed.
Subchapter 1.5.1: Added target supply voltage and
target supply current to specifications.
Subchapter 5.2.1: Pictures of ways to connect JTrace.
Subchapter 4.7 "Using DCC for memory reads"
added.
Subchapter 5.2.2: Corrected JTAG+Trace connector pinout table.
Subchapter 4.1: Added ARM966E-S to List of supported ARM cores.
Subchapter 5.5.2.2 changed.
Subchapter 5.5.2.3 added.
ARM9 download speed updated.
Subchapter 8.2.1: Screenshot "Start sequence"
updated.
Subchapter 8.2.2 "ID sequence" removed.
Chapter "Support" and "FAQ" merged.
Various improvements
Chapter "Literature and references" added.
Chapter "Hardware":
Added common information trace signals.
Added timing diagram for trace.
Chapter "Designing the target board for trace"
added.
Chapter "Related Software": Added JLinkARM.dll.
Screenshots updated.
Chapter Working with J-Link: Sketch added.

© 2004-2014 SEGGER Microcontroller GmbH & Co. KG

12

Revision

Date

By

6

051118

OO

5

051103

TQ

4

051025

OO

3
2
1

051021
051011
050818

TQ
TQ
TW

J-Link / J-Trace (UM08001)

Explanation
Chapter Working with J-Link: "Connecting multiple
J-Links to your PC" added.
Chapter Working with J-Link: "Multi core debugging" added.
Chapter Background information: "J-Link firmware" added.
Chapter Setup: "JTAG Speed" added.
Chapter Background information: "Flash programming" added.
Chapter Setup: "Scan chain configuration" added.
Some smaller changes.
Performance values updated.
Chapter "Working with J-Link" added.
Initial version.

© 2004-2014 SEGGER Microcontroller GmbH & Co. KG

13

About this document
Assumptions
This document assumes that you already have a solid knowledge of the following:
•
•
•
•

The software tools used for building your application (assembler, linker, C compiler)
The C programming language
The target processor
DOS command line

If you feel that your knowledge of C is not sufficient, we recommend The C Programming Language by Kernighan and Richie (ISBN 0-13-1103628), which describes the
standard in C-programming and, in newer editions, also covers the ANSI C standard.

How to use this manual
This manual explains all the functions and macros that the product offers. It assumes
you have a working knowledge of the C language. Knowledge of assembly programming is not required.

Typographic conventions for syntax
This manual uses the following typographic conventions:
Style

Used for

Body

Body text.

Keyword

Text that you enter at the command-prompt or that appears on
the display (that is system functions, file- or pathnames).

Parameter

Parameters in API functions.

Sample

Sample code in program examples.

Sample comment

Comments in programm examples.

Reference

Reference to chapters, sections, tables and figures or other documents.

GUIElement

Buttons, dialog boxes, menu names, menu commands.

Emphasis

Very important sections.

Table 1.1: Typographic conventions

J-Link / J-Trace (UM08001)

© 2004-2014 SEGGER Microcontroller GmbH & Co. KG

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CHAPTER

SEGGER Microcontroller GmbH & Co. KG develops
and distributes software development tools and ANSI C
software components (middleware) for embedded systems in several industries such as telecom, medical
technology, consumer electronics, automotive industry
and industrial automation.
SEGGER’s intention is to cut software development time
for embedded applications by offering compact flexible and easy to use middleware,
allowing developers to concentrate on their application.
Our most popular products are emWin, a universal graphic software package for embedded applications, and embOS, a small yet efficient real-time kernel. emWin, written
entirely in ANSI C, can easily be used on any CPU and most any display. It is complemented by the available PC tools: Bitmap Converter, Font Converter, Simulator and
Viewer. embOS supports most 8/16/32-bit CPUs. Its small memory footprint makes it
suitable for single-chip applications.
Apart from its main focus on software tools, SEGGER develops and produces programming
tools for flash micro controllers, as well as J-Link, a JTAG emulator to assist in development, debugging and production, which has rapidly become the industry standard for
debug access to ARM cores.

Corporate Office:
http://www.segger.com

EMBEDDED SOFTWARE
(Middleware)
emWin
Graphics software and GUI
emWin is designed to provide an efficient, processor- and display controller-independent graphical user
interface (GUI) for any application that
operates with a graphical display.

embOS
Real Time Operating System
embOS is an RTOS designed to offer
the benefits of a complete multitasking
system for hard real time applications
with minimal resources.

embOS/IP
TCP/IP stack
embOS/IP a high-performance TCP/IP
stack that has been optimized for
speed, versatility and a small memory
footprint.

United States Office:
http://www.segger-us.com

SEGGER TOOLS
Flasher
Flash programmer
Flash Programming tool primarily for micro controllers.

J-Link
JTAG emulator for ARM cores
USB driven JTAG interface for ARM cores.

J-Trace
JTAG emulator with trace
USB driven JTAG interface for ARM cores with
Trace memory. supporting the ARM ETM (Embedded Trace Macrocell).

J-Link / J-Trace Related Software
Add-on software to be used with SEGGER’s industry standard JTAG emulator, this includes flash
programming software and flash breakpoints.
Table 1.1:

emFile
File system
emFile is an embedded file system with
FAT12, FAT16 and FAT32 support. Various Device drivers, e.g. for NAND and
NOR flashes, SD/MMC and CompactFlash cards, are available.

USB-Stack
USB device/host stack
A USB stack designed to work on any
embedded system with a USB controller. Bulk communication and most standard device classes are supported.

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Table of Contents
1 Introduction ....................................................................................................................23
1.1
1.2
1.3
1.3.1
1.3.2
1.3.3
1.3.4
1.3.5
1.3.6
1.3.7
1.3.8
1.3.9
1.3.10
1.4
1.5
1.6
1.6.1
1.6.2
1.6.3
1.7

Requirements.......................................................................................... 24
Supported OS ......................................................................................... 25
J-Link / J-Trace models ............................................................................ 26
Model comparison.................................................................................... 27
J-Link .................................................................................................... 28
J-Link ULTRA+ ........................................................................................ 31
J-Link PRO .............................................................................................. 32
J-Link Lite ARM ....................................................................................... 33
J-Link Lite CortexM .................................................................................. 34
J-Trace ARM ........................................................................................... 35
J-Trace for Cortex-M ................................................................................ 38
Flasher ARM............................................................................................ 40
J-Link ColdFire ........................................................................................ 41
Common features of the J-Link product family ............................................. 42
Supported CPU cores ............................................................................... 43
Built-in intelligence for supported CPU-cores ............................................... 44
Intelligence in the J-Link firmware ............................................................. 44
Intelligence on the PC-side (DLL) ............................................................... 44
Firmware intelligence per model ................................................................ 46
Supported IDEs ....................................................................................... 48

2 Licensing........................................................................................................................49
2.1
2.2
2.2.1
2.2.2
2.3
2.3.1
2.4
2.4.1
2.4.2
2.4.3
2.4.4
2.4.5
2.4.6
2.4.7
2.4.8
2.4.9
2.5
2.5.1
2.5.2
2.5.3
2.5.4
2.5.5
2.5.6
2.5.7
2.5.8
2.6
2.7

................................................................. Components requiring a license50
License types .......................................................................................... 51
Built-in license ........................................................................................ 51
Key-based license.................................................................................... 51
Legal use of SEGGER J-Link software.......................................................... 52
Use of the software with 3rd party tools...................................................... 52
Original SEGGER products......................................................................... 53
J-Link .................................................................................................... 53
J-Link PLUS ............................................................................................ 53
J-link ULTRA+ ......................................................................................... 54
J-Link PRO .............................................................................................. 54
J-Trace................................................................................................... 55
J-Trace for Cortex-M ................................................................................ 55
Flasher ARM............................................................................................ 56
Flasher RX .............................................................................................. 56
Flasher PPC ............................................................................................ 57
J-Link OEM versions ................................................................................. 58
Analog Devices: mIDASLink ...................................................................... 58
Atmel: SAM-ICE ...................................................................................... 58
Digi: JTAG Link........................................................................................ 59
IAR: J-Link / J-Link KS ............................................................................. 59
IAR: J-Link Lite ....................................................................................... 59
IAR: J-Trace ........................................................................................... 60
NXP: J-Link Lite LPC Edition ...................................................................... 60
SEGGER: J-Link Lite ARM.......................................................................... 60
J-Link OBs .............................................................................................. 61
Illegal Clones .......................................................................................... 62

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3 J-Link software and documentation package.................................................................63
3.1
3.2
3.2.1
3.2.2
3.2.3
3.3
3.3.1
3.3.2
3.3.3
3.3.4
3.3.5
3.3.6
3.4
3.4.1
3.4.2
3.5
3.6
3.7
3.7.1
3.7.2
3.7.3
3.7.4
3.8
3.8.1
3.8.2
3.8.3
3.8.4
3.8.5
3.8.6
3.9
3.10
3.11
3.11.1
3.12
3.12.1
3.12.2
3.13

Software overview................................................................................... 64
J-Link Commander (Command line tool) ..................................................... 65
Commands............................................................................................. 66
Command line options ............................................................................. 80
Using command files................................................................................ 82
J-Link GDB Server ................................................................................... 83
J-Link GDB Server CL (Windows, Lunux, Mac) ............................................. 83
Debugging with J-Link GDB Server ............................................................ 84
Supported remote (monitor) commands ..................................................... 89
SEGGER-specific GDB protocol extensions .................................................101
Command line options ............................................................................104
Program termination...............................................................................115
J-Link Remote Server .............................................................................116
List of available commands......................................................................116
Tunneling mode .....................................................................................117
J-Mem Memory Viewer............................................................................120
J-Flash..................................................................................................121
J-Link SWO Viewer .................................................................................122
Usage ...................................................................................................123
List of available command line options ......................................................123
Configure SWO output after device reset ...................................................125
Target example code for terminal output ...................................................125
J-Scope ................................................................................................128
Getting Started ......................................................................................128
Project Files...........................................................................................129
Exporting Sampled Data..........................................................................129
Symbol Configuration .............................................................................130
Short Cuts.............................................................................................130
GUI Meters and Controls .........................................................................130
SWO Analyzer........................................................................................131
JTAGLoad (Command line tool) ................................................................132
J-Link RDI (Remote Debug Interface)........................................................133
Flash download and flash breakpoints .......................................................133
Processor specific tools ...........................................................................134
J-Link STR91x Commander (Command line tool) ........................................134
J-Link STM32 Unlock (Command line tool) .................................................135
J-Link Software Developer Kit (SDK) .........................................................138

4 Setup............................................................................................................................139
4.1
4.1.1
4.2
4.2.1
4.2.2
4.3
4.3.1
4.3.2
4.4
4.5
4.5.1
4.6
4.6.1
4.7
4.7.1
4.7.2
4.7.3
4.7.4
4.8
4.8.1

Installing the J-Link software and documentation pack ................................140
Setup procedure ....................................................................................140
Setting up the USB interface....................................................................143
Verifying correct driver installation ...........................................................143
Uninstalling the J-Link USB driver .............................................................144
Setting up the IP interface.......................................................................146
Configuring J-Link using J-Link Configurator...............................................146
Configuring J-Link using the webinterface ..................................................146
FAQs ....................................................................................................148
J-Link Configurator .................................................................................149
Configure J-Links using the J-Link Configurator ..........................................149
J-Link USB identification..........................................................................151
Connecting to different J-Links connected to the same host PC via USB .........151
Using the J-Link DLL ...............................................................................153
What is the JLink DLL? ............................................................................153
Updating the DLL in third-party programs..................................................153
Determining the version of JLink DLL ........................................................154
Determining which DLL is used by a program .............................................154
Getting started with J-Link and ARM DS-5 .................................................155
Replacing the RDDI DLL manually.............................................................155

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4.8.2

Using J-Link in DS-5 Development Studio ................................................. 155

5 Working with J-Link and J-Trace..................................................................................157
5.1
5.1.1
5.1.2
5.1.3
5.2
5.2.1
5.2.2
5.2.3
5.3
5.3.1
5.3.2
5.3.3
5.3.4
5.4
5.4.1
5.4.2
5.5
5.5.1
5.5.2
5.5.3
5.6
5.6.1
5.7
5.7.1
5.8
5.8.1
5.8.2
5.9
5.9.1
5.9.2
5.9.3
5.10
5.10.1
5.10.2
5.10.3
5.10.4
5.10.5
5.10.6
5.10.7
5.11
5.11.1
5.11.2
5.12
5.13
5.13.1
5.13.2
5.13.3
5.13.4
5.14
5.14.1

Connecting the target system.................................................................. 158
Power-on sequence................................................................................ 158
Verifying target device connection ........................................................... 158
Problems .............................................................................................. 158
Indicators ............................................................................................. 159
Main indicator ....................................................................................... 159
Input indicator ...................................................................................... 161
Output indicator .................................................................................... 161
JTAG interface....................................................................................... 162
Multiple devices in the scan chain ............................................................ 162
Sample configuration dialog boxes ........................................................... 162
Determining values for scan chain configuration......................................... 165
JTAG Speed .......................................................................................... 166
SWD interface ....................................................................................... 167
SWD speed ........................................................................................... 167
SWO .................................................................................................... 167
Multi-core debugging ............................................................................. 169
How multi-core debugging works ............................................................. 169
Using multi-core debugging in detail ........................................................ 170
Things you should be aware of ................................................................ 171
Connecting multiple J-Links / J-Traces to your PC ...................................... 173
How does it work? ................................................................................. 173
J-Link control panel................................................................................ 175
Tabs .................................................................................................... 175
Reset strategies .................................................................................... 181
Strategies for ARM 7/9 devices ................................................................ 181
Strategies for Cortex-M devices ............................................................... 183
Using DCC for memory access ................................................................. 186
What is required? .................................................................................. 186
Target DCC handler ............................................................................... 186
Target DCC abort handler ....................................................................... 186
J-Link script files ................................................................................... 187
Actions that can be customized ............................................................... 187
Script file API functions .......................................................................... 187
Global DLL variables .............................................................................. 193
Global DLL constants.............................................................................. 196
Script file language ................................................................................ 198
Script file writing example ...................................................................... 199
Executing J-Link script files ..................................................................... 199
Command strings .................................................................................. 200
List of available commands ..................................................................... 200
Using command strings .......................................................................... 205
Switching off CPU clock during debug ....................................................... 207
Cache handling...................................................................................... 208
Cache coherency ................................................................................... 208
Cache clean area ................................................................................... 208
Cache handling of ARM7 cores................................................................. 208
Cache handling of ARM9 cores................................................................. 208
Virtual COM Port (VCOM) ........................................................................ 209
Configuring Virtual COM Port ................................................................... 209

6 Flash download............................................................................................................211
6.1
6.2
6.3
6.4
6.4.1

Introduction.......................................................................................... 212
Licensing .............................................................................................. 213
Supported devices ................................................................................. 214
Setup for various debuggers (internal flash) .............................................. 215
IAR Embedded Workbench ...................................................................... 215

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6.4.2
6.4.3
6.4.4
6.4.5
6.4.6
6.5
6.5.1
6.5.2
6.5.3
6.6

Keil MDK ...............................................................................................215
Mentor Sourcery CodeBench ....................................................................218
J-Link GDB Server ..................................................................................218
J-Link Commander .................................................................................219
J-Link RDI .............................................................................................220
Setup for various debuggers (CFI flash) ....................................................221
IAR Embedded Workbench / Keil MDK .......................................................221
J-Link GDB Server ..................................................................................222
J-Link commander..................................................................................222
Using the DLL flash loaders in custom applications......................................224

7 Flash breakpoints.........................................................................................................225
7.1
7.2
7.2.1
7.3
7.4
7.4.1
7.4.2
7.5

Introduction ..........................................................................................226
Licensing...............................................................................................227
Free for evaluation and non-commercial use ..............................................227
Supported devices..................................................................................228
Setup & compatibility with various debuggers ............................................229
Setup ...................................................................................................229
Compatibility with various debuggers ........................................................229
FAQ......................................................................................................230

8 J-Flash SPI ..................................................................................................................231
8.1
8.1.1
8.1.2
8.1.3
8.1.4
8.2
8.2.1
8.3
8.3.1
8.3.2
8.3.3
8.4
8.4.1
8.4.2
8.5
8.5.1
8.5.2
8.5.3
8.5.4
8.6
8.6.1
8.6.2
8.7
8.7.1
8.8
8.8.1
8.9
8.9.1
8.10
8.10.1
8.11
8.11.1
8.11.2

Introduction ..........................................................................................232
What is J-Flash SPI? ...............................................................................232
J-Flash SPI CL (Windows, Linux, Mac) .......................................................232
Features ...............................................................................................232
Requirements ........................................................................................232
Licensing...............................................................................................233
Introduction ..........................................................................................233
Getting Started ......................................................................................234
Setup ...................................................................................................234
Using J-Flash SPI for the first time............................................................234
Menu structure ......................................................................................235
Settings ................................................................................................239
Project Settings .....................................................................................239
Global Settings ......................................................................................241
Command Line Interface .........................................................................243
Overview ..............................................................................................243
Command line options ............................................................................243
Batch processing ....................................................................................245
Programming multiple targets in parallel ...................................................245
Create a new J-Flash SPI project ..............................................................247
Creating a new J-Flash SPI project ...........................................................247
Serial number programming ....................................................................248
Device specifics......................................................................................249
SPI flashes with multiple erase commands.................................................249
Target systems ......................................................................................250
Which flash devices can be programmed? ..................................................250
Performance ..........................................................................................251
Performance values ................................................................................251
Background information ..........................................................................252
SPI interface connection..........................................................................252
Support ................................................................................................253
Troubleshooting .....................................................................................253
Contacting support .................................................................................253

9 RDI...............................................................................................................................255
9.1
9.1.1
9.2

Introduction ..........................................................................................256
Features ...............................................................................................256
Licensing...............................................................................................257

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9.3
9.3.1
9.3.2
9.3.3
9.3.4
9.3.5
9.4
9.4.1
9.4.2
9.4.3
9.4.4
9.5
9.5.1
9.5.2
9.5.3
9.5.4
9.5.5

Setup for various debuggers ................................................................... 258
IAR Embedded Workbench IDE ................................................................ 258
ARM AXD (ARM Developer Suite, ADS) ..................................................... 261
ARM RVDS (RealView developer suite)...................................................... 263
GHS MULTI ........................................................................................... 268
KEIL MDK (µVision IDE).......................................................................... 271
Configuration ........................................................................................ 274
Configuration file JLinkRDI.ini.................................................................. 274
Using different configurations .................................................................. 274
Using mutliple J-Links simulatenously....................................................... 274
Configuration dialog ............................................................................... 274
Semihosting.......................................................................................... 283
Overview .............................................................................................. 283
The SWI interface .................................................................................. 283
Implementation of semihosting in J-Link RDI ............................................. 284
Semihosting with AXD ............................................................................ 284
Unexpected / unhandled SWIs................................................................. 285

10 RTT ............................................................................................................................287
10.1
10.2
10.2.1
10.2.2
10.2.3
10.2.4
10.2.5
10.2.6
10.3
10.3.1
10.3.2
10.3.3
10.3.4
10.4
10.4.1
10.4.2
10.5
10.6

Introduction.......................................................................................... 288
How RTT works ..................................................................................... 289
Target implementation ........................................................................... 289
Locating the Control Block ...................................................................... 289
Internal structures ................................................................................. 289
Requirements........................................................................................ 290
Performance ......................................................................................... 291
Memory footprint................................................................................... 291
RTT Communication ............................................................................... 292
J-Link RTT Viewer .................................................................................. 292
RTT Client............................................................................................. 297
RTT Logger ........................................................................................... 297
RTT in other host applications ................................................................. 297
Implementation..................................................................................... 298
API functions ........................................................................................ 298
Configuration defines ............................................................................. 304
Example code ....................................................................................... 306
FAQ ..................................................................................................... 307

11 Device specifics .........................................................................................................309
11.1
11.1.1
11.2
11.2.1
11.2.2
11.3
11.4
11.5
11.6
11.6.1
11.7
11.8
11.9
11.10
11.10.1
11.11
11.11.1
11.11.2
11.11.3
11.11.4
11.12

Analog Devices...................................................................................... 310
ADuC7xxx ............................................................................................ 310
ATMEL ................................................................................................. 312
AT91SAM7............................................................................................ 313
AT91SAM9............................................................................................ 315
DSPGroup............................................................................................. 316
Ember.................................................................................................. 317
Energy Micro......................................................................................... 318
Freescale.............................................................................................. 319
Kinetis family ........................................................................................ 319
Fujitsu ................................................................................................. 322
Itron .................................................................................................... 323
Infineon ............................................................................................... 324
Luminary Micro ..................................................................................... 325
Unlocking LM3Sxxx devices..................................................................... 326
NXP ..................................................................................................... 327
LPC ARM7-based devices ........................................................................ 328
Reset (Cortex-M3 based devices)............................................................. 329
LPC288x flash programming.................................................................... 329
LPC43xx:.............................................................................................. 329
OKI ..................................................................................................... 330

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11.13
11.14
11.14.1
11.15
11.15.1
11.16
11.16.1
11.16.2
11.16.3
11.16.4
11.17
11.17.1
11.17.2
11.17.3
11.17.4
11.17.5
11.17.6
11.17.7
11.18

Renesas ................................................................................................331
Samsung ..............................................................................................332
S3FN60D ..............................................................................................332
Silicon Labs ...........................................................................................333
EFM32 series devices ..............................................................................333
ST Microelectronics.................................................................................334
STR91x.................................................................................................335
STM32F10xxx ........................................................................................335
STM32F2xxx..........................................................................................337
STM32F4xxx..........................................................................................338
Texas Instruments .................................................................................339
AM335x ................................................................................................339
AM35xx / AM37xx ..................................................................................340
OMAP4430 ............................................................................................340
OMAP-L138 ...........................................................................................340
TMS470M ..............................................................................................340
OMAP3530 ............................................................................................341
OMAP3550 ............................................................................................341
Toshiba.................................................................................................342

12 Target interfaces and adapters ..................................................................................343
12.1
12.1.1
12.1.2
12.1.3
12.1.4
12.2
12.2.1
12.2.2
12.2.3
12.2.4
12.3
12.3.1
12.4
12.5

20-pin J-Link connector...........................................................................344
Pinout for JTAG ......................................................................................344
Pinout for SWD ......................................................................................347
Pinout for SWD + Virtual COM Port (VCOM) ...............................................349
Pinout for SPI ........................................................................................350
38-pin Mictor JTAG and Trace connector ....................................................351
Connecting the target board ....................................................................351
Pinout...................................................................................................352
Assignment of trace information pins between ETM architecture versions .......354
Trace signals .........................................................................................354
19-pin JTAG/SWD and Trace connector .....................................................356
Target power supply ...............................................................................357
9-pin JTAG/SWD connector......................................................................358
Adapters ...............................................................................................359

13 Background information .............................................................................................361
13.1
13.1.1
13.1.2
13.1.3
13.1.4
13.2
13.2.1
13.2.2
13.2.3
13.3
13.4
13.4.1
13.4.2
13.4.3
13.4.4
13.5
13.5.1
13.5.2

JTAG ....................................................................................................362
Test access port (TAP) ............................................................................362
Data registers........................................................................................362
Instruction register.................................................................................362
The TAP controller ..................................................................................363
Embedded Trace Macrocell (ETM) .............................................................365
Trigger condition ....................................................................................365
Code tracing and data tracing ..................................................................365
J-Trace integration example - IAR Embedded Workbench for ARM.................365
Embedded Trace Buffer (ETB) ..................................................................369
Flash programming ................................................................................370
How does flash programming via J-Link / J-Trace work? ..............................370
Data download to RAM ............................................................................370
Data download via DCC...........................................................................370
Available options for flash programming ....................................................370
J-Link / J-Trace firmware.........................................................................372
Firmware update ....................................................................................372
Invalidating the firmware ........................................................................372

14 Designing the target board for trace ..........................................................................375
14.1
14.1.1
14.1.2

Overview of high-speed board design........................................................376
Avoiding stubs .......................................................................................376
Minimizing Signal Skew (Balancing PCB Track Lengths) ...............................376

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14.1.3
14.1.4
14.2
14.2.1
14.3

Minimizing Crosstalk .............................................................................. 376
Using impedance matching and termination .............................................. 376
Terminating the trace signal.................................................................... 377
Rules for series terminators .................................................................... 377
Signal requirements ............................................................................... 378

15 Support and FAQs .....................................................................................................379
15.1
15.1.1
15.2
15.2.1
15.2.2
15.3
15.4

Measuring download speed ..................................................................... 380
Test environment .................................................................................. 380
Troubleshooting .................................................................................... 381
General procedure ................................................................................. 381
Typical problem scenarios ....................................................................... 381
Contacting support ................................................................................ 383
Frequently Asked Questions .................................................................... 384

16 Glossary.....................................................................................................................385
17 Literature and references...........................................................................................391

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Chapter 1
Introduction

This chapter gives a short overview about J-Link and J-Trace.

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1.1

CHAPTER 1

Introduction

Requirements
Host System
To use J-Link or J-Trace you need a host system running Windows 2000 or later. For a
list of all operating systems which are supported by J-Link, please refer to Supported
OS on page 25.

Target System
A target system with a supported CPU is required.
You should make sure that the emulator you are looking at supports your target CPU.
For more information about which J-Link features are supported by each emulator,
please refer to Model comparison on page 27.

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1.2

Supported OS
J-Link/J-Trace can be used on the following operating systems:
•
•
•
•
•
•
•
•
•
•
•

Microsoft Windows
Microsoft Windows
Microsoft Windows
Microsoft Windows
Microsoft Windows
Windows 7
Windows 7 x64
Windows 8
Windows 8 x64
Linux
Mac OSX 10.5 and

J-Link / J-Trace (UM08001)

2000
XP
XP x64
Vista
Vista x64

higher

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CHAPTER 1

1.3

Introduction

J-Link / J-Trace models
J-Link / J-Trace is available in different variations, each designed for different purposes / target devices. Currently, the following models of J-Link / J-Trace are available:
•
•
•
•
•
•
•

J-Link
J-Link PLUS
J-Link PRO
J-Link ULTRA
J-Link ULTRA+
J-Trace ARM
J-Trace for Cortex-M

In the following, the different J-Link / J-Trace models are described and the changes
between the different hardware versions of each model are listed. To determine the
hardware version of your J-Link / J-Trace, the first step should be to look at the label
at the bottom side of the unit. J-Links / J-Traces have the hardware version printed
on the back label.
If this is not the case with your J-Link / J-Trace, start JLink.exe. As part of the initial
message, the hardware version is displayed.

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1.3.1

Model comparison

The following tables show the features which are included in each J-Link / J-Trace
model.
Hardware features
J-Link
Plus

J-Link
USB
Ethernet

yes
no

yes
no

J-Link
ULTRA+
yes
no

J-Link
Pro

J-Trace
for Cortex-M

yes
yes

yes
no
Tracing:
Cortex-M3/M4
No tracing:
ARM7/9/11,
Cortex-M0/M0+/
M1
Cortex-A5/A8/
A9/R4
yes
yes
yes
yes

ARM7/9/11,
Cortex-A5/A8/A9/R4,
Supported cores
Cortex-M0/M0+/M1/M3/M4,
Renesas RX

JTAG
SWD
SWO
ETM Trace

yes
yes
yes
no

yes
yes
yes
no

yes
yes
yes
no

yes
yes
yes
no

J-Trace
yes
no

ARM 7/9

yes
no
no
yes

Software features
Software features are features implemented in the software running on the host.
Software features can either come with the J-Link or be added later using a license
string from Segger.

J-Link
J-Flash
Flash breakpoints
download 2

Flash
GDB Server
RDI

1

J-Link
PLUS

J-Link
ULTRA+

J-Link
Pro

J-Trace
for
Cortex-M

J-Trace

yes(opt)

yes

yes

yes

yes

yes

yes(opt)

yes

yes

yes

yes

yes

yes

yes

yes

yes

yes

yes

yes
yes(opt)

yes
yes

yes
yes

yes
yes

yes
yes

yes
yes

1

In order to use the flash breakpoints with J-Link no additional license for flash
download is required. The flash breakpoint feature allows setting an unlimited number of breakpoints even if the application program is not located in RAM, but in flash
memory. Without this feature, the number of breakpoints which can be set in flash is
limited to the number of hardware breakpoints (typically two for ARM 7/9, up to six
for Cortex-M) For more information about flash breakpoints, please refer to Flash
breakpoints on page 225.

2

Most IDEs come with its own flashloaders, so in most cases this feature is not
essential for debugging applications in flash. The J-Link flash download feature is
mainly used in debug environments where the debugger does not come with an own
flashloader (for example, the GNU Debugger). For more information about how flash
download via FlashDL works, please refer to Flash download on page 211.

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CHAPTER 1

1.3.2

Introduction

J-Link

J-Link is a JTAG emulator designed for ARM cores. It connects
via USB to a PC running Microsoft Windows 2000 or later. For a
complete list of all operating systems which are supported,
please refer to Supported OS on page 25. J-Link has a built-in
20-pin JTAG connector, which is compatible with the standard
20-pin connector defined by ARM.

1.3.2.1 Additional features
•
•
•
•
•
•
•

Direct download into flash memory of most popular microcontrollers supported
Full-speed USB 2.0 interface
Serial Wire Debug supported
Serial Wire Viewer supported
Download speed up to 1 MBytes/second*
Debug interface (JTAG/SWD/...) speed up to 15 MHz
RDI interface available, which allows using J-Link with RDI
compliant software

*The actual speed depends on various factors, such as JTAG/
SWD, clock speed, host CPU core etc.

1.3.2.2 Specifications
The following table gives an overview about the specifications (general, mechanical,
electrical) for J-Link.
General
Supported OS
Electromagnetic compatibility (EMC)
Operating temperature
Storage temperature
Relative humidity (non-condensing)

For a complete list of all operating systems which are supported, please refer
to Supported OS on page 25.
EN 55022, EN 55024
+5°C ... +60°C
-20°C ... +65 °C
Max. 90% rH
Mechanical

Size (without cables)
Weight (without cables)

100mm x 53mm x 27mm
70g
Available interfaces

USB interface

USB 2.0, full speed
JTAG 20-pin
(14-pin adapter available)

Target interface

JTAG/SWD Interface, Electrical
Power supply
Target interface voltage (VIF)
Target supply voltage
Target supply current
Reset Type
Reset low level output voltage (VOL)

USB powered
Max. 50mA + Target Supply current.
1.2V ... 5V
4.5V ... 5V (if powered with 5V on USB)
Max. 300mA
Open drain. Can be pulled low or
tristated.
V OL <= 10% of VIF

For the whole target voltage range (1.2V <= V IF <= 5V)
LOW level input voltage (VIL)

V IL <= 40% of V IF

Table 1.1: J-Link specifications

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HIGH level input voltage (V IH)

V IH >= 60% of VIF
For 1.8V <= V IF <= 3.6V

LOW level output voltage (VOL) with a
load of 10 kOhm
HIGH level output voltage (VOH ) with a
load of 10 kOhm

V OL <= 10% of VIF
V OH >= 90% of V IF

For 3.6 <= V IF <= 5V
LOW level output voltage (VOL) with a
load of 10 kOhm
HIGH level output voltage (VOH ) with a
load of 10 kOhm

V OL <= 20% of VIF
V OH >= 80% of V IF

JTAG/SWD Interface, Timing
SWO sampling frequency
Data input rise time (Trdi)

Max. 7.5 MHz
Trdi <= 20ns

Data input fall time (Tfdi)
Data output rise time (Trdo)

T fdi <= 20ns

Data output fall time (T fdo)
Clock rise time (Trc)

T fdo <= 10ns

Clock fall time (Tfc)
Table 1.1: J-Link specifications

Trdo <= 10ns
Trc <= 3ns
T fc <= 3ns

1.3.2.3 Hardware versions
Versions 1-4 (Obsolete)
Obsolete.

Version 5.0 (Obsolete)
Identical to version 4.0 with the following exception:
•
•
•

•

Uses a 32-bit RISC CPU.
Maximum download speed (using DCC) is over 700 Kbytes/second.
JTAG speed: Maximum JTAG frequency is 12 MHz; possible JTAG speeds are:
48 MHz / n, where n is 4, 5, ..., resulting in speeds of:
12.000 MHz (n = 4)
9.600 MHz (n = 5)
8.000 MHz (n = 6)
6.857 MHz (n = 7)
6.000 MHz (n = 8)
5.333 MHz (n = 9)
4.800 MHz (n = 10)
Supports adaptive clocking.

Version 5.2 (Obsolete)
Identical to version 5.0 with the following exception:
•

Target interface: RESET is open drain.

Version 5.3 (Obsolete)
Identical to version 5.2 with the following exception:
•

5V target supply current limited
5V target supply (pin 19) of Kick-Start versions of J-Link is current monitored
and limited. J-Link automatically switches off 5V supply in case of over-current to
protect both J-Link and host computer. Peak current (<= 10 ms) limit is 1A,
operating current limit is 300mA.

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CHAPTER 1

Introduction

Version 5.4 (Obsolete)
Identical to version 5.3 with the following exception:
•

Supports 5V target interfaces.

Version 6.0 (Obsolete)
Identical to version 5.4 with the following exception:
•
•
•
•

Outputs can be tristated (Effectively disabling the JTAG interface)
Supports SWD interface.
SWD speed: Software implementation. 4 MHz maximum SWD speed.
J-Link supports SWV (Speed limited to 500 kHz)

Version 7.0 (Obsolete)
Identical to version 6.0 with the following exception:
•

Uses an additional pin to the UART unit of the target hardware for SWV support
(Speed limited to 6 MHz).

Version 8.0
Identical to version 7.0 with the following exception:
•

SWD support for non-3.3V targets.

Version 9.1
•

New design based on STM32F205.

Version 9.2
Identical to version 9.1 with the following exception:
•

Pin 1 (VTref) is used for measuring target reference voltage only. Buffers on JLink side are no longer powered through this pin but via the J-Link internal voltage supplied via USB.

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1.3.3

J-Link ULTRA+

J-Link ULTRA+ is a JTAG/SWD emulator designed for ARM/Cortex and other supported CPUs. It is fully compatible to the
standard J-Link and works with the same PC software. Based on
the highly optimized and proven J-Link, it offers even higher
speed as well as target power measurement capabilities due to
the faster CPU, built-in FPGA and High speed USB interface. It
connects via USB to a PC running Microsoft Windows 2000 or
later. For a complete list of all operating systems which are supported, please refer to Supported OS on page 19.# J-link ULTRA
has a built-in 20-pin JTAG/SWD connector.

1.3.3.1 Additional features
•
•
•
•
•
•
•
•
•
•
•
•

Fully compatible to the standard J-Link
Very high performance for all supported CPU cores
Hi-Speed USB 2.0 interface
Download speed up to 3 MByte/second*
Debug interface (JTAG/SWD/...) speed up to 15 MHz
Serial Wire Debug (SWD) supported
Serial Wire Viewer (SWV) supported
SWO sampling frequencies up to 100 MHz
Serial Wire Output (SWO) supported
Target power can be supplied
Comes with built-in licenses for: Unlimited number of breakpoints in flash
(FlashBP), J-Link GDBServer, J-Link RDI, J-Link RDDI and J-Flash (production
programming software).
Target power consumption can be measured with high accuracy.

*The actual speed depends on various factors, such as JTAG/SWD, clock speed, host
CPU core etc.

1.3.3.2 Specifications
The following table gives an overview about the specifications (general, mechanical,
electrical) for J-link ULTRA. All values are valid for J-link ULTRA hardware version 1.
Note:
Some specifications, especially speed, are likely to be improved in the
future with newer versions of the J-Link software (freely available).
General
Supported OS
Electromagnetic compatibility (EMC)
Operating temperature
Storage temperature
Relative humidity (non-condensing)

For a complete list of all operating systems which are supported, please refer
to Supported OS on page 25.
EN 55022, EN 55024
+5°C ... +60°C
-20°C ... +65 °C
Max. 90% rH
Mechanical

Size (without cables)
Weight (without cables)

100mm x 53mm x 27mm
73g
Available interfaces

USB interface
Target interface

USB 2.0, Hi-Speed
20-pin J-Link debug interface connector
JTAG/SWD Interface, Electrical

Target interface voltage (VIF)
Target supply voltage

1.8V ... 5V
4.5V ... 5V

Table 1.2: J-link ULTRA specifications

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CHAPTER 1

Target supply current
Reset Type
Reset low level output voltage (VOL)

Introduction

Max. 300mA
Open drain. Can be pulled low or
tristated.
V OL <= 10% of VIF

For the whole target voltage range (1.8V <= V IF <= 5V)
LOW level input voltage (VIL)
HIGH level input voltage (VIH)

V IL <= 40% of V IF
V IH >= 60% of VIF
For 1.8V <= V IF <= 3.6V

LOW level output voltage (V OL) with a
load of 10 kOhm
HIGH level output voltage (VOH ) with a
load of 10 kOhm

V OL <= 10% of VIF
V OH >= 90% of V IF

For 3.6 <= V IF <= 5V
LOW level output voltage (V OL) with a
load of 10 kOhm
HIGH level output voltage (VOH ) with a
load of 10 kOhm

V OL <= 20% of VIF
V OH >= 80% of V IF

JTAG/SWD Interface, Timing
SWO sampling frequency
Data input rise time (Trdi)

Max. 100 MHz
Trdi <= 20ns

Data input fall time (Tfdi)
Data output rise time (Trdo)

T fdi <= 20ns

Data output fall time (Tfdo)

T fdo <= 10ns

Clock rise time (Trc)

Trc <= 3ns

Clock fall time (Tfc)

T fc <= 3ns

Trdo <= 10ns

Analog power measurement interface
Sampling frequency
Resolution

50 kHz
1 mA

Table 1.2: J-link ULTRA specifications

1.3.4

J-Link PRO

J-Link PRO is a JTAG emulator designed for ARM cores. It is
fully compatible to J-Link and connects via Ethernet/USB to a
PC running Microsoft Windows 2000 or later, Linux or Mac OS X.
For a complete list of all operating systems which are supported, please refer to Supported OS on page 19. J-Link Pro
comes with licenses for all J-Link related SEGGER software.

1.3.4.1 Additional features
•
•
•
•
•
•
•
•
•

Fully compatible to J-Link
More memory for future firmware extensions (ARM11, XScale, Cortex R4 and Cortex A8)
Additional LEDs for power and RESET indication
Comes with web interface for easy TCP/IP configuration
(built-in web server)
Serial Wire Debug supported
Serial Wire Viewer supported
Download speed up to 3 MByte/second
Comes with built-in licenses for: Unlimited number of
breakpoints in flash (FlashBP), J-Link GDBServer, J-Link RDI, J-Link RDDI and JFlash (production programming software).
Embedded Trace Buffer (ETB) support

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•

Galvanic isolation from host via Ethernet

1.3.4.2 Hardware versions
Version 1.1
Compatible to J-Link.
•

Provides an additional Ethernet interface which allows to communicate with JLink via TCP/IP.

Version 4
•

New design based on STM32F407 + FPGA (Cyclone IV)Version 4.3

Identical to version 4 with the following exception:
•

1.3.5

Pin 1 (VTref) is used for measuring target reference voltage only. Buffers on JLink side are no longer powered through this pin but via the J-Link internal voltage supplied via USB.

J-Link Lite ARM

J-Link Lite ARM is a fully functional OEM-version of J-Link. If
you are selling evaluation-boards, J-Link Lite ARM is an inexpensive emulator solution for you. Your customer receives a
widely acknowledged JTAG-emulator which allows him to start
right away with his development.

1.3.5.1 Additional features
•
•
•
•
•
•
•

Very small form factor
Fully software compatible to J-Link
Supports any ARM7/9/11, Cortex-A5/A8/A9, Cortex-M0/M0+/M1/M3/M4, CortexR4/R5 core
JTAG clock up to 4 MHz
SWD, SWO supported for Cortex-M devices
Flash download into supported MCUs
Standard 20-pin 0.1 inch JTAG connector (compatible to J-Link)

1.3.5.2 Specifications
The following table gives an overview about the specifications (general, mechanical,
electrical) for J-Link Lite ARM. All values are valid for J-Link hardware version 8.
General
Supported OS
Electromagnetic compatibility (EMC)
Operating temperature
Storage temperature
Relative humidity (non-condensing)
Size (without cables)
Weight (without cables)

For a complete list of all operating systems which are supported, please refer
to Supported OS on page 25.
EN 55022, EN 55024
+5°C ... +60°C
-20°C ... +65 °C
Max. 90% rH
28mm x 26mm x 7mm
6g
Mechanical

USB interface

USB 2.0, full speed
JTAG 20-pin
(14-pin adapter available)

Target interface

JTAG/SWD Interface, Electrical
Table 1.3: J-Link Lite specifications

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Introduction

USB powered
Max. 50mA + Target Supply current.

Power supply
Target interface voltage (VIF)
Target supply voltage
Target supply current
LOW level input voltage (VIL)

3.3V
4.5V ... 5V (if powered with 5V on USB)
Max. 300mA
Max. 40% of V IF

HIGH level input voltage (VIH)

Min. 60% of VIF

JTAG/SWD Interface, Timing
Data input rise time (Trdi)

Max. 20ns

Data input fall time (Tfdi)
Data output rise time (Trdo)

Max. 20ns

Data output fall time (Tfdo)
Clock rise time (Trc)

Max. 10ns

Max. 10ns
Max. 10ns

Clock fall time (Tfc)
Table 1.3: J-Link Lite specifications

1.3.6

Max. 10ns

J-Link Lite CortexM

J-Link Lite CortexM is a specific OEM-version of SEGGER J-Link
Lite which is designed to be used with Cortex-M devices. If you
are selling evaluation-boards, J-Link Lite CortexM is an inexpensive emulator solution for you. Your customer receives a
widely acknowledged JTAG/SWD-emulator which allows him to start right away with
his development.
•
•
•
•
•
•
•
•

Very small form factor
Fully software compatible to J-Link
Any Cortex-M0/M0+/M1/M3/M4 core supported
JTAG clock up to 4 MHz
SWD, SWO supported
Flash download into supported MCUs
Standard 9- or 19-pin 0.05'' Samtec FTSH connector
3.3V target interface voltage

1.3.6.1 Specifications
The following table gives an overview about the specifications (general, mechanical,
electrical) for J-Link Lite Cortex-M.
General
For a complete list of all operating systems which are supported, please refer
to Supported OS on page 25.
EN 55022, EN 55024
+5°C ... +60°C
-20°C ... +65 °C
Max. 90% rH
41mm x 34mm x 8mm
6g

Supported OS
Electromagnetic compatibility (EMC)
Operating temperature
Storage temperature
Relative humidity (non-condensing)
Size (without cables)
Weight (without cables)

Mechanical
USB interface

USB 2.0, full speed
19-pin 0.05'' Samtec FTSH connector
9-pin 0.05'' Samtec FTSH connector

Target interface

JTAG/SWD Interface, Electrical
Table 1.4: J-Link Lite Cortex-M specifications

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USB powered
Max. 50mA + Target Supply current.

Power supply
Target interface voltage (VIF)
Target supply voltage
Target supply current
LOW level input voltage (VIL)

3.3V
4.5V ... 5V
Max. 300mA
Max. 40% of VIF

HIGH level input voltage (V IH)

Min. 60% of V IF

JTAG/SWD Interface, Timing
Data input rise time (Trdi)

Max. 20ns

Data input fall time (Tfdi)
Data output rise time (Trdo)

Max. 20ns

Data output fall time (T fdo)
Clock rise time (Trc)

Max. 10ns

Max. 10ns
Max. 10ns

Clock fall time (Tfc)
Table 1.4: J-Link Lite Cortex-M specifications

1.3.7

Max. 10ns

J-Trace ARM

J-Trace is a JTAG emulator designed for ARM cores which
includes trace (ETM) support. It connects via USB to a PC running Microsoft Windows 2000 or later. For a complete list of all
operating systems which are supported, please refer to Supported OS on page 19. J-Trace has a built-in 20-pin JTAG connector and a built in 38-pin JTAG+Trace connector, which are
compatible to the standard 20-pin connector and 38-pin connector defined by ARM.

1.3.7.1 Additional features
•
•
•
•
•

Supports tracing on ARM7/9 targets
JTAG speed up to 12 MHz
Download speed up to 420 Kbytes/second *
DCC speed up to 600 Kbytes/second *
Comes with built-in licenses for: Unlimited number of
breakpoints in flash (FlashBP), J-Link GDBServer, J-Link
RDI, J-Link RDDI and J-Flash (production programming
software).

* Measured with J-Trace, ARM7 @ 50 MHz, 12MHz JTAG speed.

1.3.7.2 Specifications for J-Trace
General
Supported OS
Electromagnetic Compatibility (EMC)
Operating Temperature
Storage Temperature
Relative Humidity (non-condensing)
Size (without cables)
Weight (without cables)

For a complete list of all operating systems which are supported, please refer
to Supported OS on page 25.
EN 55022, EN 55024
+5°C ... +40°C
-20°C ... +65 °C
<90% rH
123mm x 68mm x 30mm
120g

Mechanical
USB Interface

USB 2.0, full speed

Table 1.5: J-Trace specifications

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Introduction

JTAG 20-pin (14-pin adapter available)
JTAG+Trace: Mictor, 38-pin

Target Interface

JTAG/SWD Interface, Electrical
Power Supply
Supported Target interface voltage

USB powered < 300mA
3.0 - 3.6 V (5V adapter available)

Table 1.5: J-Trace specifications

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1.3.7.3 Download speed
The following table lists performance values (Kbytes/s) for writing to memory (RAM):
Hardware
J-Trace Rev. 1

ARM7 via JTAG
420.0 Kbytes/s
(12MHz JTAG)

ARM9 via JTAG
280.0 Kbytes/s
(12MHz JTAG)

Table 1.6: Download speed differences between hardware revisions

All tests have been performed in the testing environment which is described on Measuring download speed on page 380.
The actual speed depends on various factors, such as JTAG, clock speed, host CPU
core etc.

1.3.7.4 Hardware versions
Version 1
This J-Trace uses a 32-bit RISC CPU. Maximum download speed is approximately 420
KBytes/second (600 KBytes/second using DCC).

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CHAPTER 1

1.3.8

Introduction

J-Trace for Cortex-M

J-Trace for Cortex-M is a JTAG/SWD emulator designed for Cortex-M cores which includes trace (ETM) support. J-Trace for
Cortex-M can also be used as a J-Link and it also supports
ARM7/9 cores. Tracing on ARM7/9 targets is not supported.

1.3.8.1 Additional features
•
•
•

Has all the J-Link functionality
Supports tracing on Cortex-M targets
Comes with built-in licenses for: Unlimited number of
breakpoints in flash (FlashBP), J-Link GDBServer, J-Link
RDI, J-Link RDDI and J-Flash (production programming
software).

1.3.8.2 Specifications
The following table gives an overview about the specifications (general, mechanical,
electrical) for J-Trace for Cortex-M. All values are valid for the latest hardware version of J-Trace for Cortex-M.
General
For a complete list of all operating systems which are supported, please refer
to Supported OS on page 19.
EN 55022, EN 55024
+5°C ... +60°C
-20°C ... +65 °C
Max. 90% rH
123mm x 68mm x 30mm
120g

Supported OS
Electromagnetic compatibility (EMC)
Operating temperature
Storage temperature
Relative humidity (non-condensing)
Size (without cables)
Weight (without cables)

Mechanical
USB interface

USB 2.0, Hi-Speed
JTAG/SWD 20-pin
(14-pin adapter available)
JTAG/SWD + Trace 19-pin

Target interface

JTAG/SWD Interface, Electrical

Target interface voltage (VIF)
Target supply voltage
Target supply current
LOW level input voltage (VIL)

USB powered
Max. 50mA + Target Supply current.
1.2V ... 5V
4.5V ... 5V (if powered with 5V on USB)
Max. 300mA
Max. 40% of V IF

HIGH level input voltage (VIH)

Min. 60% of VIF

Power supply

JTAG/SWD Interface, Timing
Data input rise time (Trdi)

Max. 20ns

Data input fall time (Tfdi)
Data output rise time (Trdo)

Max. 20ns

Data output fall time (Tfdo)

Max. 10ns

Max. 10ns

Table 1.7: J-Trace for Cortex-M3 specifications

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Clock rise time (Trc)

Max. 3ns

Clock fall time (Tfc)

Max. 3ns
Trace Interface, Electrical
USB powered
Max. 50mA + Target Supply current.

Power supply
Target interface voltage (VIF)
Voltage interface low pulse (VIL)
Voltage interface high pulse (VIH )

1.2V ... 5V
Max. 40% of VIF
Min. 60% of V IF

Trace Interface, Timing
TRACECLK low pulse width (Twl)

Min. 2ns

TRACECLK high pulse width (Twh)

Min. 2ns

Data rise time (Trd)

Max. 3ns

Data fall time (Tfd)

Max. 3ns

Clock rise time (Trc)

Max. 3ns

Clock fall time (Tfc)
Data setup time (Ts)

Max. 3ns
Min. 3ns

Data hold time (Th)

Min. 2ns

Table 1.7: J-Trace for Cortex-M3 specifications

1.3.8.3 Download speed
The following table lists performance values (Kbytes/s) for writing to memory (RAM):
Hardware
J-Trace for Cortex-M3 V2
J-Trace for Cortex-M V3.1

Cortex-M3
190 Kbytes/s (12MHz SWD)
760 KB/s (12 MHz JTAG)
190 Kbytes/s (12MHz SWD)
1440 KB/s (25 MHz JTAG)

Table 1.8: Download speed differences between hardware revisions

The actual speed depends on various factors, such as JTAG, clock speed, host CPU
core etc.

1.3.8.4 Hardware versions
Version 2
Obsolete.

Version 3.1
Identical to version 2.0 with the following exceptions:
•
•
•

Hi-Speed USB
Voltage range for trace signals extended to 1.2 - 3.3 V
Higher download speed

J-Link / J-Trace (UM08001)

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CHAPTER 1

1.3.9

Introduction

Flasher ARM

Flasher ARM is a programming tool for microcontrollers with onchip or external Flash memory and ARM core. Flasher ARM is
designed for programming flash targets with the J-Flash software or stand-alone. In addition to that Flasher ARM has all of
the J-Link functionality. For more information about Flasher
ARM, please refer to UM08007, Flasher ARM User’s Guide.

1.3.9.1 Specifications
The following table gives an overview about the specifications
(general, mechanical, electrical) for Flasher ARM.

General
For a complete list of all operating systems which are supported, please refer
to Supported OS on page 19.

Supported OS

Mechanical
USB interface
Target interface

USB 2.0, full speed
JTAG/SWD 20-pin
JTAG Interface, Electrical

Target interface voltage (VIF)

USB powered
Max. 50mA + Target Supply current.
1.2V ... 5V

Target supply voltage
Target supply current

4.5V ... 5V (if powered with 5V on USB)
Max. 300mA

Power supply

For the whole target voltage range (1.8V <= V IF <= 5V)
LOW level input voltage (VIL)

Max. 40% of V IF

HIGH level input voltage (VIH)

Min. 60% of VIF
For 1.8V <= V IF <= 3.6V

LOW level output voltage (V OL) with a
load of 10 kOhm
HIGH level output voltage (VOH ) with a
load of 10 kOhm

Max. 10% of V IF
Min. 90% of VIF

For 3.6 <= V IF <= 5V
LOW level output voltage (V OL) with a
load of 10 kOhm
HIGH level output voltage (VOH ) with a
load of 10 kOhm

Max. 20% of V IF
Min. 80% of VIF

SWD Interface, Electrical
Power supply
Target interface voltage (VIF)
Target supply voltage

USB powered
Max. 50mA + Target Supply current.
1.2V ... 5V (SWD interface is 5V tolerant
but can output a maximum of 3.3V SWD
signals)
4.5V ... 5V (if powered with 5V on USB)

Table 1.9: Flasher ARM specifications

J-Link / J-Trace (UM08001)

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Target supply current
LOW level input voltage (VIL)

Max. 0.8V

HIGH level input voltage (V IH)

Min. 2.0V

LOW level output voltage (VOL) with a
load of 10 kOhm
HIGH level output voltage (VOH ) with a
load of 10 kOhm

Max. 300mA

Max. 0.5V
Min. 2.85V

Table 1.9: Flasher ARM specifications

1.3.10 J-Link ColdFire
J-Link ColdFire is a BDM emulator designed for ColdFire® cores.
It connects via USB to a PC running Microsoft Windows 2000,
Windows XP, Windows 2003, or Windows Vista. J-Link ColdFire
has a built-in 26-pin BDM connector, which is compatible to the
standard 26-pin connector defined by Freescale. For more information about J-Link ColdFire BDM 26, please refer to UM08009,
J-Link ColdFire BDM26 User’s Guide.

J-Link / J-Trace (UM08001)

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CHAPTER 1

1.4

Introduction

Common features of the J-Link product family
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•

USB 2.0 interface (Full-Speed/Hi-Speed, depends on J-Link model)
Any ARM7/9/11 (including thumb mode), Cortex-A5/A8, Cortex-M0/M1/M3/M4,
Cortex-R4 core supported
Automatic core recognition
Maximum JTAG speed 12/25 MHz (depends on J-Link model)
Seamless integration into all major IDEs (https://segger.com/jlink-ide-integration.html)
No power supply required, powered through USB
Support for adaptive clocking
All JTAG signals can be monitored, target voltage can be measured
Support for multiple devices
Fully plug and play compatible
Standard 20-pin JTAG/SWD connector, 19-pin JTAG/SWD and Trace connector,
standard 38-pin JTAG+Trace connector
USB and 20-pin ribbon cable included
Memory viewer (J-Mem) included
Remote server included, which allows using J-Trace via TCP/IP networks
RDI interface available, which allows using J-Link with RDI compliant software
Flash programming software (J-Flash) available
Flash DLL available, which allows using flash functionality in custom applications
Software Developer Kit (SDK) available
Full integration with the IAR C-SPY® debugger; advanced debugging features
available from IAR C-SPY debugger.
14-pin JTAG adapter available
J-Link 19-pin Cortex-M Adapter available
J-Link 9-pin Cortex-M Adapter available
Adapter for 5V JTAG targets available for hardware revisions up to 5.3
Optical isolation adapter for JTAG/SWD interface available
Target power supply via pin 19 of the JTAG/SWD interface (up to 300 mA to target with overload protection), alternatively on pins 11 and 13 of the Cortex-M
19-pin trace connector

J-Link / J-Trace (UM08001)

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1.5

Supported CPU cores
J-Link / J-Trace has been tested with the following cores, but should work with any
ARM7/9/11, Cortex-M0/M1/M3/M4 and Cortex-A5/A8/A9/R4 core. If you experience
problems with a particular core, do not hesitate to contact Segger.
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•

ARM7TDMI (Rev 1)
ARM7TDMI (Rev 3)
ARM7TDMI-S (Rev 4)
ARM720T
ARM920T
ARM922T
ARM926EJ-S
ARM946E-S
ARM966E-S
ARM1136JF-S
ARM1136J-S
ARM1156T2-S
ARM1156T2F-S
ARM1176JZ-S
ARM1176JZF
ARM1176JZF-S
Cortex-A5
Cortex-A8
Cortex-A9
Cortex-M0
Cortex-M1
Cortex-M3
Cortex-M4
Cortex-R4
Renesas RX

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CHAPTER 1

1.6

Introduction

Built-in intelligence for supported CPU-cores
In general, there are two ways to support a CPU-core in the J-Link software:
1.
2.

Intelligence in the J-Link firmware
Intelligence on the PC-side (DLL)

Having the intelligence in the firmware is ideal since it is much more powerful and
robust. The J-Link PC software automatically detects which implementation level is
supported for the connected CPU-core. If intelligence in the firmware is available, it
is used. If you are using a J-Link that does not have intelligence in the firmware and
only PC-side intelligence is available for the connected CPU, a warning message is
shown.

1.6.1

Intelligence in the J-Link firmware

On newer J-Links, the intelligence for a new CPU-core is also available in the J-Link
firmware which means that for these J-Links, the target sequences are no longer
generated on the PC-side but directly inside the J-Link. Having the intelligence in the
firmware leads to improved stability and higher performance.

1.6.2

Intelligence on the PC-side (DLL)

This is the basic implementation level for support of a CPU-core. This implementation
is not J-Link model dependent, since no intelligence for the CPU-core is necessary in
the J-Link firmware. This means, all target sequences (JTAG/SWD/...) are generated
on the PC-side and the J-Link simply sends out these sequences and sends the result
back to the DLL. Using this way of implementation also allows old J-Links to be used
with new CPU cores as long as a DLL-Version is used which has intelligence for the
CPU.
But there is one big disadvantage of implementing the CPU core support on the DLLside: For every sequence which shall be sent to the target a USB or Ethernet transaction is triggered. The long latency especially on a USB connection significantly affects
the performance of J-Link. This is true especially when performing actions where JLink has to wait for the CPU frequently. An example is a memory read/write operation
which needs to be followed by status read operations or repeated until the memory
operation is completed. Performing this kind of task with only PC-side intelligence
requires to either make some assumption like: Operation is completed after a given
number of cycles. Or it requires to make a lot of USB/Ethernet transactions. The first
option (fast mode) will not work under some circumstances such as low CPU speeds,
the second (slow mode) will be more reliable but very slow due to the high number of
USB/Ethernet transactions. It simply boils down to: The best solution is having intelligence in the emulator itself!
J-Link / J-Trace (UM08001)

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1.6.2.1 Limitations of PC-side implementations
•

•

•

Instability, especially on slow targets
Due to the fact that a lot of USB transactions would cause a very bad performance of J-Link, PC-side implementations are on the assumption that the CPU/
Debug interface is fast enough to handle the commands/requests without the
need of waiting. So, when using the PC-side-intelligence, stability cannot be
guaranteed in all cases, especially if the target interface speed (JTAG/SWD/...) is
significantly higher than the CPU speed.
Poor performance
Since a lot more data has to be transferred over the host interface (typically
USB), the resulting download speed is typically much lower than for implementations with intelligence in the firmware, even if the number of transactions over
the host interface is limited to a minimum (fast mode).
No support
Please understand that we cannot give any support if you are running into problems when using a PC-side implementation.

Note:
Due to these limitations, we recommend to use PC-side implementations
for evaluation only.

J-Link / J-Trace (UM08001)

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CHAPTER 1

1.6.3

Introduction

Firmware intelligence per model

There are different models of J-Link / J-Trace which have built-in intelligence for different CPU-cores. In the following, we will give you an overview about which model
of J-Link / J-Trace has intelligence for which CPU-core.

1.6.3.1 Current models
The table below lists the firmware CPU support for J-Link & J-Trace models currently
available.
Version

J-Link / J-Trace
model

ARM
7/9

ARM
11

CortexA/R

JTAG

JTAG

JTAG

Cortex-M
JTAG

SWD

Renesas
RX600
JTAG

J-Link

8

!

!

!

!

!

!

J-Link Pro

3

!

!

!

!

!

!

J-link ULTRA

1

!

!

!

!

!

!

J-Link Lite ARM

8

!

!

!

!

!

"
!

J-Link Lite Cortex-M 8

"

"

"

!

!

"

J-Link Lite RX

8

"

"

"

"

"

!

J-Trace ARM

1

!

"

"

"

"

"

"

"

"

!

!

"

J-Trace for Cortex-M 3

Table 1.10: Built-in intelligence of current J-Links

J-Link / J-Trace (UM08001)

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1.6.3.2 Older models
The table below lists the firmware CPU support for older J-Link & J-Trace models
which are not sold anymore.
Version

J-Link / J-Trace
model

ARM
7/9

ARM
11

CortexA/R

JTAG

JTAG

JTAG

JTAG

Cortex-M
SWD

Renesas
RX600
JTAG

J-Link

3

"

"

"

"

not supported

"

J-Link

4

"

"

"

"

not supported

"

J-Link

5

!

"

"

"

not supported

"

J-Link

6

!

"

"

"

!

"

J-Link

7

!

"

"

"

!

"

J-Link Pro

1

!

!

!

!

!

!

"

"

!

!

!

"

J-Trace for Cortex-M 1

Table 1.11: Built-in intelligence of older J-Link models

J-Link / J-Trace (UM08001)

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CHAPTER 1

1.7

Introduction

Supported IDEs
J-Link / J-Trace can be used with different IDEs. Some IDEs support J-Link directly,
for other ones additional software (such as J-Link RDI) is necessary in order to use JLink. The following tables list which features of J-Link / J-Trace can be used with the
different IDEs.

ARM7/9
Debug
support 4

IDE
IAR EWARM
Keil MDK
Rowley
CodeSourcery
Yargato (GDB)
RDI compliant
toolchains such as
RVDS/ADS

Flash
download

Trace
support 3

Flash
breakpoints

yes
yes
yes
yes
yes

yes
yes
yes
no
yes

yes
yes
no
no
yes

yes
no
no
no
no

yes 1

yes 1

yes 1

no

ARM Cortex-M3
IDE
IAR EWARM
Keil MDK
Rowley
CodeSourcery
Yargato (GDB)

Debug
support 4
yes
yes
yes
yes
yes

Flash
download
yes
yes
yes
no
yes

Flash
breakpoints
yes
yes
no
no
yes

Trace
support 3
yes
yes
no
no
no

SWO
support
yes
yes
no
no
no

ARM11
ARM11 has currently been tested with IAR EWARM only.
Debug
support 4

IDE

Flash
download

Flash
breakpoints

Trace
support 3

IAR EWARM

yes

no 2

no2

no

Rowley

yes

no 2

no

no

yes

2

Yargato (GDB)

no

no

2

1

Requires J-Link RDI license for download of more than 32KBytes

2

Coming soon

no

3

Requires emulator with trace support

4

Debug support includes the following: Download to RAM, memory read/write, CPU
register read/write, Run control (go, step, halt), software breakpoints in RAM and
hardware breakpoints in flash memory.

J-Link / J-Trace (UM08001)

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Chapter 2
Licensing

This chapter describes the different license types of J-Link related software and the
legal use of the J-Link software with original SEGGER and OEM products.

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CHAPTER 2

2.1

Licensing

Components requiring a license
The following programs/features require a full-featured J-Link (PLUS, ULTRA+, PRO,
J-Trace) or an additional license for the J-Link base model:
•
•
•

J-Flash
J-Link RDI
Flash breakpoints (FlashBP)

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2.2

License types
For each of the software components which require an additional license, there are
different types of licenses which are explained in the following.

Built-in License
This type of license is easiest to use. The customer does not need to deal with a
license key. The software automatically finds out that the connected J-Link contains
the built-in license(s). The license is burned into the J-Link debug probe and can be
used on any computer the J-Link is connected to. This type of license applies to the JLink PLUS, J-Link ULTRA+ and J-Link Pro.

Key-based license
This type of license is used if you already have a J-Link, but order a license for a JLink software component at a later time. In addition to that, the key-based license is
used for trial licenses. To enable this type of license you need to obtain a license key
from SEGGER. Free trial licenses are available upon request from www.segger.com.
This license key has to be added to the J-Link license management. How to enter a
license key is described in detail in Licensing on page 227. Every license can be used
on different PCs, but only with the J-Link the license is for. This means that if you
want to use flash breakpoints with other J-Links, every J-Link needs a license.

2.2.1

Built-in license

This type of license is easiest to use. The customer does not need to deal with a
license key. The software automatically finds out that the connected J-Link contains
the built-in license(s). To check what licenses the used J-Link have, simply open the
J-Link commander (JLink.exe). The J-Link commander finds and lists all of the JLink’s licenses automatically, as can be seen in the screenshot below.

The J-Link PLUS in the example above contains licenses for all features. Note that
GDB and FlashDL feature are no longer required.

2.2.2

Key-based license

When using a key-based license, a license key is required in order to enable the feature. License keys can be added via the J-Link License Manager. How to enter a
license via the license manager is described in Licensing on page 227. Like the builtin license, the key-based license is only valid for one J-Link, so if another J-Link is
used it needs a separate license.

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CHAPTER 2

2.3

Licensing

Legal use of SEGGER J-Link software
The software consists of proprietary programs of SEGGER, protected under copyright
and trade secret laws. All rights, title and interest in the software are and shall
remain with SEGGER. For details, please refer to the license agreement which needs
to be accepted when installing the software. The text of the license agreement is also
available as entry in the start menu after installing the software.

Use of software
SEGGER J-Link software may only be used with original SEGGER products and authorized OEM products. The use of the licensed software to operate SEGGER product
clones is prohibited and illegal.

2.3.1

Use of the software with 3rd party tools

For simplicity, some components of the J-Link software are also distributed by partners with software tools designed to use J-Link. These tools are primarily debugging
tools, but also memory viewers, flash programming utilities as well as software for
other purposes. Distribution of the software components is legal for our partners, but
the same rules as described above apply for their usage: They may only be used with
original SEGGER products and authorized OEM products. The use of the licensed software to operate SEGGER product clones is prohibited and illegal.

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2.4

Original SEGGER products
The following products are original SEGGER products for which the use of the J-Link
software is allowed:

2.4.1

J-Link

J-Link is a JTAG emulator designed for ARM cores. It connects
via USB to a PC running Microsoft Windows 2000, Windows XP,
Windows 2003, Windows Vista or Windows 7. J-Link has a builtin 20-pin JTAG connector, which is compatible with the standard
20-pin connector defined by ARM.

Licenses
Comes with built-in licenses for flash download.

2.4.2

J-Link PLUS
J-Link PLUS is a USB powered JTAG emulator supporting a large
number of CPU cores.
Based on a 32-bit RISC CPU, it can communicate at high speed
with the supported target CPUs. J-Link is used around the world
in tens of thousand places for development and production
(flash programming) purposes.
J-Link is supported by all major IDEs such as IAR EWARM, Keil
MDK, Rowley CrossWorks, Atollic TrueSTUDIO, IAR EWRX,
Renesas HEW, Renesas e2studio, and many others.

Licenses
Comes with liicenses for: Unlimited breakpoints in flash memory (Unlimited Flash Breakpoints), RDI and J-Flash

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CHAPTER 2

2.4.3

Licensing

J-link ULTRA+

J-link ULTRA+ is a JTAG/SWD emulator designed for ARM/Cortex and other supported CPUs. It is fully compatible to the standard J-Link and works with the same PC software. Based on the
highly optimized and proven J-Link, it offers even higher speed
as well as target power measurement capabilities due to the
faster CPU, built-in FPGA and High speed USB interface.
It connects via USB to a PC running Microsoft Windows 2000,
Windows XP, Windows 2003, Windows Vista or Windows 7.
J-link ULTRA has a built-in 20-pin JTAG/SWD connector.

Licenses
Unlimited breakpoints in flash memory (Unlimited Flash Breakpoints), RDI and J-Flash

2.4.4

J-Link PRO
J-Link PRO is a JTAG emulator designed for ARM cores. It connects via USB or Ethernet to a PC running Microsoft Windows
2000, Windows XP, Windows 2003, Windows Vista or Windows
7. J-Link has a built-in 20-pin JTAG connector, which is compatible with the standard 20-pin connector defined by ARM.

Licenses
Comes with built-in licenses for all J-Link related software products: J-Link FlashDL, FlashBP, RDI, J-Link GDB Server and JFlash.

J-Link / J-Trace (UM08001)

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2.4.5

J-Trace

J-Trace is a JTAG emulator designed for ARM cores which
includes trace (ETM) support. It connects via USB to a PC running Microsoft Windows 2000, Windows XP, Windows 2003,
Windows Vista or Windows 7. J-Trace has a built-in 20-pin JTAG
connector and a built in 38-pin JTAG+Trace connector, which is
compatible with the standard 20-pin connector and 38-pin connector defined by ARM.

Licenses
Comes with built-in licenses for flash download.

2.4.6

J-Trace for Cortex-M
J-Trace for Cortex-M is a JTAG/SWD emulator designed for Cortex-M cores which include trace (ETM) support. J-Trace for Cortex-M can also be used as a regular J-Link.

Licenses
Comes with built-in licenses for all J-Link related software
products:
•Unlimited flash breakpoints
•RDI / RDDI
•J-Flash
Note:In order to use ETM trace on ARM7/9 targets, a J-Trace is
needed.

J-Link / J-Trace (UM08001)

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CHAPTER 2

2.4.7

Licensing

Flasher ARM

Flasher ARM is a programming tool for microcontrollers with onchip or external Flash memory and ARM core. Flasher ARM is
designed for programming flash targets with the J-Flash software or stand-alone. In addition to that Flasher ARM has all of
the J-Link functionality. Flasher ARM connects via USB or via
RS232 interface to a PC, running Microsoft Windows 2000, Windows XP, Windows 2003 or Windows Vista. Flasher ARM has a
built-in 20-pin JTAG connector, which is compatible with the
standard 20-pin connector defined by ARM.

Licenses
Comes with built-in licenses for flash download and J-Flash.

2.4.8

Flasher RX
Flasher RX is a programming tool for Renesas RX600 series
microcontrollers with on-chip or external flash memory and
Renesas RX core. Flasher RX is designed for programming flash
targets with the J-Flash software or stand-alone. In addition to
that Flasher RX has all of the J-Link RX functionality. Flasher RX
connects via Ethernet, USB or via RS232 interface to a PC, running Microsoft Windows 2000, Windows XP, Windows 2003,
Windows Vista or Windows 7.
Flasher RX itself has a built-in 20-pin JTAG connector but is
shipped with an 14-pin adapter for Renesas RX devices.

Licenses
Comes with built-in licenses for flash download and J-Flash.

J-Link / J-Trace (UM08001)

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2.4.9

Flasher PPC

Flasher ARM is a programming tool for microcontrollers with onchip or external Flash memory and ARM core. Flasher ARM is
designed for programming flash targets with the J-Flash software or stand-alone. In addition to that Flasher ARM has all of
the J-Link functionality. Flasher ARM connects via USB or via
RS232 interface to a PC, running Microsoft Windows 2000, Windows XP, Windows 2003 or Windows Vista. Flasher ARM has a
built-in 20-pin JTAG connector, which is compatible with the
standard 20-pin connector defined by ARM.

Licenses
Comes with built-in licenses for flash download and J-Flash.

J-Link / J-Trace (UM08001)

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CHAPTER 2

2.5

Licensing

J-Link OEM versions
There are several different OEM versions of J-Link on the market. The OEM versions
look different, but use basically identical hardware. Some of these OEM versions are
limited in speed, some can only be used with certain chips and some of these have
certain add-on features enabled, which normally requires a license. In any case, it
should be possible to use the J-Link software with these OEM versions. However,
proper function cannot be guaranteed for OEM versions. SEGGER Microcontroller
does not support OEM versions; support is provided by the respective OEM.

2.5.1

Analog Devices: mIDASLink

mIDASLink is an OEM version of J-Link, sold by Analog Devices.

Limitations
mIDASLink works with Analog Devices chips only. This limitation
can NOT be lifted; if you would like to use J-Link with a device
from an other manufacturer, you need to buy a separate J-Link.

Licenses
Licenses for RDI, J-Link FlashDL and FlashBP are included. Other
licenses can be added.

2.5.2

Atmel: SAM-ICE

SAM-ICE is an OEM version of J-Link, sold by Atmel.

Limitations
SAM-ICE works with Atmel devices only. This limitation can NOT
be lifted; if you would like to use J-Link with a device from an
other manufacturer, you need to buy a separate J-Link.

Licenses
Licenses for RDI and GDB Server are included. Other licenses can
be added.

J-Link / J-Trace (UM08001)

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59

2.5.3

Digi: JTAG Link

Digi JTAG Link is an OEM version of J-Link, sold by Digi International.

Limitations
Digi JTAG Link works with Digi devices only. This limitation can
NOT be lifted; if you would like to use J-Link with a device from an
other manufacturer, you need to buy a separate J-Link.

Licenses
License for GDB Server is included. Other licenses can be added.

2.5.4

IAR: J-Link / J-Link KS

IAR J-Link / IAR J-Link KS are OEM versions of J-Link, sold by IAR.

Limitations
IAR J-Link / IAR J-Link KS cannot be used with Keil MDK. This limitation can NOT be lifted; if you would like to use J-Link with Keil
MDK, you need to buy a separate J-Link. IAR J-Link does not support kickstart power.

Licenses
No licenses are included. All licenses can be added.

2.5.5

IAR: J-Link Lite

IAR J-Link Lite is an OEM version of J-Link, sold by IAR.

Limitations
IAR J-Link Lite cannot be used with Keil MDK. This limitation can
NOT be lifted; if you would like to use J-Link with Keil MDK, you
need to buy a separate J-Link.
JTAG speed is limited to 4 MHz.

Licenses
No licenses are included. All licenses can be added.
Note:
IAR J-Link is only delivered and supported as part of Starter-Kits. It is not
sold to end customer directly and not guaranteed to work with custom hardware.

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2.5.6

Licensing

IAR: J-Trace

IAR J-Trace is an OEM version of J-Trace, sold by IAR.

Limitations
IAR J-Trace cannot be used with Keil MDK. This limitation can NOT
be lifted; if you would like to use J-Trace with Keil MDK, you need
to buy a separate J-Trace.

Licenses
No licenses are included. All licenses can be added.

2.5.7

NXP: J-Link Lite LPC Edition

J-Link Lite LPC Edition is an OEM version of J-Link, sold by NXP.

Limitations
J-Link Lite LPC Edition only works with NXP devices. This limitation can NOT be lifted; if you would like to use J-Link with a
device from an other manufacturer, you need to buy a separate
J-Link.

Licenses
No licenses are included.

2.5.8

SEGGER: J-Link Lite ARM

J-Link Lite ARM is a fully functional OEM-version of SEGGER JLink. If you are selling evaluation-boards, J-Link Lite ARM is an
inexpensive emulator solution for you. Your customer receives a
widely acknowledged JTAG-emulator which allows him to start
right away with his development.

Limitations
JTAG speed is limited to 4 MHz

Licenses
No licenses are included. All licenses can be added.

Note
J-Link Lite ARM is only delivered and supported as part of Starter Kits. It is not sold
to end customers and not guaranteed to work with custom hardware.

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2.6

J-Link OBs
J-Link OBs (J-Link On Board) are single chip versions of J-Link which are used on various evalboards. It is legal to use J-Link software with these boards.

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2.7

CHAPTER 2

Licensing

Illegal Clones
Clones are copies of SEGGER products which use the copyrighted SEGGER Firmware
without a license. It is strictly prohibited to use SEGGER J-Link software with illegal
clones of SEGGER products. Manufacturing and selling these clones is an illegal act
for various reasons, amongst them trademark, copyright and unfair business practise
issues.
The use of illegal J-Link clones with this software is a violation of US, European and
other international laws and is prohibited.
If you are in doubt if your unit may be legally used with SEGGER J-Link software,
please get in touch with us.
End users may be liable for illegal use of J-Link software with clones.

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Chapter 3
J-Link software and documentation package

This chapter describes the contents of the J-Link software and documentation package which can be downloaded from www.segger.com.

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3.1

CHAPTER 3

J-Link software and documentation package

Software overview
The J-Link software and documentation package, which is available for download
from http://www.segger.com/jlink-software.html includes some applications to be
used with J-Link. It also comes with USB-drivers for J-Link and documentations in pdf
format.
Software

Description

JLink Commander

Command-line tool with basic functionality for target analysis.

J-Link GDB Server

The J-Link GDB Server is a server connecting to the GNU
Debugger (GDB) via TCP/IP. It is required for toolchains using
the GDB protocol to connect to J-Link.

J-Link GDB Server
command line version

Command line version of the J-Link GDB Server. Same functionality as the GUI version.

J-Link Remote
Server

Utility which provides the possibility to use J-Link / J-Trace
remotely via TCP/IP.

J-Mem Memory
Viewer

Target memory viewer. Shows the memory content of a running target and allows editing as well.

J-Flasha

Stand-alone flash programming application. For more information about J-Flash please refer to J-Flash ARM User’s Guide
(UM08003).

J-Link SWO Viewer

Free-of-charge utility for J-Link. Displays the terminal output
of the target using the SWO pin. Can be used in parallel with a
debugger or stand-alone.

J-Scope

J-Scope is a free-of-charge software to analyze and visualize
data on a microcontroller in real-time, while the target is running.

J-Link SWO Analyzer

Command line tool that analyzes SWO RAW output and stores
it into a file.

JTAGLoad

Command line tool that opens an svf file and sends the data in
it via J-Link / J-Trace to the target.

J-Link Configurator

GUI-based configuration tool for J-Link. Allows configuration of
USB identification as well as TCP/IP identification of J-Link. For
more information about the J-Link Configurator, please refer to
J-Link Configurator on page 149.

RDI supporta

Provides Remote Debug Interface (RDI) support. This allows
the user to use J-Link with any RDI-compliant debugger.

Processor specific
tools

Free command-line tools for handling specific processors.
Included are: STR9 Commander and STM32 Unlock.

Table 3.1: J-Link / J-Trace related software

a. Full-featured J-Link (PLUS, PRO, ULTRA+) or an additional license for J-Link base model required.

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3.2

J-Link Commander (Command line tool)
J-Link Commander (JLink.exe) is a tool that can be used for verifying proper installation of the USB driver and to verify the connection to the target CPU, as well as for
simple analysis of the target system. It permits some simple commands, such as
memory dump, halt, step, go etc. to verify the target connection.

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3.2.1

J-Link software and documentation package

Commands

The table below lists the available commands of J-Link Commander. All commands
are listed in alphabetical order within their respective categories. Detailed descriptions of the commands can be found in the sections that follow.
Command (short form)
clrBP
clrWP
device
erase
exit (qc, q)
exitonerror (eoe)
f
go (g)
halt (h)
hwinfo
is
loadfile
log
mem
mem8
mem16
mem32
mem64
mr
ms
power
r
regs
rnh
rreg
rx
savebin
setBP
setPC
setWP
sleep
speed
st
step (s)
unlock
verifybin
w1
w2
w4
wreg
fdelete (fdel)
flist
fread (frd)
fshow
J-Link / J-Trace (UM08001)

Explanation
Basic
Clear breakpoint.
Clear watchpoint.
Selects a device.
Erase internal flash of selected device.
Closes J-Link Commander.
Commander exits after error.
Prints firmware info.
Starts the CPU core.
Halts the CPU core.
Show hardware info.
Scan chain select register length.
Load data file into target memory.
Enables log to file.
Read memory.
Read 8-bit items.
Read 16-bit items.
Read 32-bit items.
Read 64-bit items.
Measures reaction time of RTCK pin.
Measures length of scan chain.
Switch power supply for target.
Resets and halts the target.
Shows all current register values.
Resets without halting the target.
Shows a specific register value.
Reset target with delay.
Saves target memory into binary file.
Set breakpoint.
Set the PC to specified value.
Set watchpoint.
Waits the given time (in milliseconds).
Set target interface speed.
Shows the current hardware status.
Single step the target chip.
Unlocks a device.
Compares memory with data file.
Write 8-bit items.
Write 16-bit items.
Write 32-bit items.
Write register.
Flasher I/O
Delete file on emulator.
List directory on emulator.
Read file from emulator.
Read and display file from emulator.
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Command (short form)
fsize (fsz)
fwrite (fwr)
ip
usb

J-Link / J-Trace (UM08001)

Explanation
Display size of file on emulator.
Write file to emulator.
Connection
Connect to J-Link Pro via TCP/IP.
Connect to J-Link via USB.

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3.2.1.1 clrBP
This command removes a breakpoint set by J-Link.

Syntax
clrBP 

Parameter
BP_Handle

Meaning
Handle of breakpoint to be removed.

Example
clrBP 1

3.2.1.2 clrWP
This command removes a watchpoint set by J-Link.

Syntax
clrWP 

Parameter
WP_Handle

Meaning
Handle of watchpoint to be removed.

Example
clrWP 0x2

3.2.1.3 device
Selects a specific device J-Link shall connect to and performs a reconnect. In most
cases explicit selection of the device is not necessary. Selecting a device enables the
user to make use of the J-Link flash programming functionality as well as using
unlimited breakpoints in flash memory.
For some devices explicit device selection is mandatory in order to allow the DLL to
perform special handling needed by the device.
Some commands require that a device is set prior to use them.

Syntax
device 

Parameter
DeviceName

Meaning
Valid device name: Device is selected.
?:
Shows a device selection dialog.

Example
device stm32f407ig

3.2.1.4 erase
Erases all flash sectors of the current device. A device has to be specified previously.

Syntax
erase

3.2.1.5 exit (qc, q)
This command closes the target connection, the connection to the J-Link and exits JLink Commander.

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Syntax
q

3.2.1.6 exitonerror (eoe)
This command toggles whether J-Link Commander exits on error or not.

Syntax
ExitOnError <1|0>\

Parameter
<1|0>

Meaning
1: J-Link Commander will now exit on Error.
0: J-Link Commander will no longer exit on Error.

Example
eoe 1

3.2.1.7 f
Prints firmware and hardware version info. Please notice that minor hardware revisions may not be displayed, as they do not have any effect on the feature set.

Syntax
f

3.2.1.8 fdelete (fdel)
On emulators which support file I/O this command deletes a specific file.

Syntax
fdelete ]

Parameter
FileName

Meaning
File to delete from the Flasher.

Example
fdelete Flasher.dat

3.2.1.9 flist
On emulators which support file I/O this command shows the directory tree of the
Flasher.

Syntax
flist

3.2.1.10 fread (frd)
On emulators which support file I/O this command reads a specific file. Offset applies
to both destination and source file.

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Syntax
fread   [ []]

Parameter
EmuFile
HostFile
Offset
NumBytes

Meaning
File name to read from.
Destination file on the host.
Specifies the offset in the file, at which data reading is started.
Maximum number of bytes to read.

Example
fread Flasher.dat C:\Project\Flasher.dat

3.2.1.11 fshow
On emulators which support file I/O this command reads and prints a specific file.
Currently, only Flasher models support file I/O.

Syntax
fshow  [-a] [ []]

Parameter
FileName
a
Offset
NumBytes

Meaning
Source file name to read from the Flasher.
If set, Input will be parsed as text instead of being shown as hex.
Specifies the offset in the file, at which data reading is started.
Maximum number of bytes to read.

Example
fshow Flasher.dat

3.2.1.12 fsize (fsz)
On emulators which support file I/O this command gets the size of a specific file. Currently, only Flasher models support file I/O.

Syntax
fsize ]

Parameter
FileName

Meaning
Source file name to read from the Flasher.

Example
fsize Flasher.dat

3.2.1.13 fwrite (fwr)
On emulators which support file I/O this command writes a specific file. Currently,
only Flasher models support file I/O.
NumBytes is limited to 512 bytes at once. This means, if you want to write e.g. 1024
bytes, you have to send the command twice, using an appropriate offset when sending it the second time. Offset applies to both destination and source file.

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Syntax
fwrite   [ []]

Parameter
EmuFile
HostFile
Offset
NumBytes

Meaning
File name to write to.
Source file on the host
Specifies the offset in the file, at which data writing is started.
Maximum number of bytes to write.

Example
fwrite Flasher.dat C:\Project\Flasher.dat

3.2.1.14 go (g)
Starts the CPU. In order to avoid setting breakpoints it allows to define a maximum
number of instructions which can be simulated/emulated. This is particulary useful
when the program is located in flash and flash breakpoints are used. Simulating
instructions avoids to reprogram the flash and speeds up (single) stepping.

Syntax
go [ []]

Parameter

NumSteps

Flags

Meaning
Maximum number of instructions allowed to be simulated. Instruction simulation stops whenever a breakpointed instruction is hit, an
instruction which cannot be simulated/emulated is hit or when NumSteps is reached.
0: Do not start the CPU if a BP is in range of NumSteps
1: Overstep BPs

Example
go //Simply starts the CPU
go 20, 1

3.2.1.15 halt (h)
Halts the CPU Core. If successful, shows the current CPU registers.

Syntax
halt

3.2.1.16 hwinfo
This command can be used to get information about the power consumption of the
target (if the target is powered via J-Link). It also gives the information if an overcurrent happened.

Syntax
hwinfo

3.2.1.17 ip
Closes any existing connection to J-Link and opens a new one via TCP/IP.
If no IP Address is specified, the Emulator selection dialog shows up.

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Syntax
ip []

Parameter

Addr

Meaning
Valid values:
IP Address: Connects the J-Link with the specified IP-Address
Host Name: Resolves the host name and connects to it.
*: Invokes the Emulator selection dialog.

Example
ip 192.168.6.3

3.2.1.18 is
This command returns information about the length of the scan chain select register.

Syntax
is

3.2.1.19 loadfile
This command programs a given data file to a specified destination address.
Currently supported data files are:
•
•
•
•
•
•

*.mot
*.srec
*.s19
*.s
*.hex
*.bin

Syntax
loadfile  []

Parameter
Filename
Addr

Meaning
Source filename
Destination address (Required for *.bin files)

Example
loadfile C:\Work\test.bin 0x20000000

3.2.1.20 log
Set path to logfile allowing the DLL to output logging information.
If the logfile already exist, the contents of the current logfile will be overwritten.

Syntax
log 

Parameter
Filename

Meaning
Log filename

Example
log C:\Work\log.txt

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3.2.1.21 mem
The command reads memory from the target system. If necessary, the target CPU is
halted in order to read memory.

Syntax
mem

[:],  (hex)

Parameter
Zone
Addr
Numbytes

Meaning
Name of memory zone to access.
Start address.
Number of bytes to read. Maximum is 0x100000.

Example
mem 0, 100

3.2.1.22 mem8
The command reads memory from the target system in units of bytes. If necessary,
the target CPU is halted in order to read memory.

Syntax
mem8

[:],  (hex)

Parameter
Zone
Addr
NumBytes

Meaning
Name of memory zone to access.
Start address.
Number of bytes to read. Maximum is 0x10000.

Example
mem8 0, 100

3.2.1.23 mem16
The command reads memory from the target system in units of 16-bits. If necessary,
the target CPU is halted in order to read memory.

Syntax
mem16

[:],  (hex)

Parameter
Zone
Addr
NumBytes

Meaning
Name of memory zone to access.
Start address.
Number of bytes to read. Maximum is 0x8000.

Example
mem16 0, 100

3.2.1.24 mem32
The command reads memory from the target system in units of 32-bits. If necessary,
the target CPU is halted in order to read memory.

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Syntax
mem32

[:],  (hex)

Parameter
Zone
Addr
NumBytes

Meaning
Name of memory zone to access.
Start address.
Number of bytes to read. Maximum is 0x4000.

Example
mem32 0, 100

3.2.1.25 mem64
The command reads memory from the target system in units of 64-bits. If necessary,
the target CPU is halted in order to read memory.

Syntax
mem64

[:],  (hex)

Parameter
Zone
Addr
NumBytes

Meaning
Name of memory zone to access.
Start address.
Number of bytes to read. Maximum is 0x4000.

Example
mem64 0, 100

3.2.1.26 mr
Measure reaction time of RTCK pin.

Syntax
mr []

Parameter
RepCount

Meaning
Number of times the test is repeated (Default: 1).

Example
mr 3

3.2.1.27 ms
Measures the number of bits in the specified scan chain.

Syntax
ms 

Parameter
ScanChain

Meaning
Scan chain to be measured.

Example
ms 1

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3.2.1.28 power
This command sets the status of the power supply over pin 19 of the JTAG connector.
The KS(Kickstart) versions of J-Link have the 5V supply over pin 19 activated by
default. This feature is useful for some targets that can be powered over the JTAG
connector.

Syntax
power  [perm]

Parameter
State
perm

Meaning
Valid values: On, Off
Sets the specified State value as default.

Example
f

3.2.1.29 r
Resets and halts the target.

Syntax
r

3.2.1.30 regs
Shows all current register values.

Syntax
regs

3.2.1.31 rnh
This command performs a reset but without halting the device.

Syntax
rnh

3.2.1.32 rreg
The function prints the value of the specified CPU register.

Syntax
rreg 

Parameter
RegIndex

Meaning
Register to read.

Example
rreg 15

3.2.1.33 rx
Resets and halts the target. It is possible to define a delay in milliseconds after reset.
This function is useful for some target devices which already contain an application or
a boot loader and therefore need some time before the core is stopped, for example
to initialize hardware, the memory management unit (MMU) or the external bus
interface.

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Syntax
rx 

Parameter
DelayAfterReset

Meaning
Delay in ms.

Example
rx 10

3.2.1.34 savebin
Saves target memory into binary file.

Syntax
savebin , ,  (hex)

Parameter
Filename
Addr
NumBytes

Meaning
Destination file
Source address.
Number of bytes to read.

Example
savebin C:\Work\test.bin 0x0000000 0x100

3.2.1.35 setBP
This command sets a breakpoint of a specific type at a specified address. Which
breakpoint modes are available depends on the CPU that is used.

Syntax
setBP  [[A/T]/[W/H]] [S/H]

Parameter
Addr
A/T

W/H
S/H

Meaning
Address to be breakpointed.
Only for ARM7/9/11 and Cortex-R4 devices:
A: ARM mode
T: THUMB mode
Only for MIPS devices:
W: MIPS32 mode (Word)
H: MIPS16 mode (Half-word)
S: Force software BP
H: Force hardware BP

Example
setBP 0x8000036

3.2.1.36 setPC
Sets the PC to the specified value.

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Syntax
setpc 

Parameter
Addr

Meaning
Address the PC should be set to.

Example
setpc 0x59C

3.2.1.37 setWP
This command inserts a new watchpoint that matches the specified parameters. The
enable bit for the watchpoint as well as the data access bit of the watchpoint unit are
set automatically by this command. Moreover the bits DBGEXT, CHAIN and the
RANGE bit (used to connect one watchpoint with the other one) are automatically
masked out. In order to use these bits you have to set the watchpoint by writing the
ICE registers directly.

Syntax
setWP  [] [] [ [ []]]

Parameter
Addr
Accesstype
Size
Data

DataMask

AddrMask

Meaning
Address to be watchpointed.
Specifies the control data on which data event has been set:
R: read access
W: write access
Valid values: S8 | S16 | S32
Specifies to monitor an n-bit access width at the selected address.
Specifies the Data on which watchpoint has been set.
Specifies data mask used for comparison. Bits set to 1 are masked
out, so not taken into consideration during data comparison. Please
note that for certain cores not all Bit-Mask combinations are supported by the core-debug logic. On some cores only complete bytes
can be masked out (e.g. PIC32) or similar.
Specifies the address mask used for comparison. Bits set to 1 are
masked out, so not taken into consideration during address comparison. Please note that for certain cores not all Bit-Mask combinations are supported by the core-debug logic. On some cores only
complete bytes can be masked out (e.g. PIC32) or similar.

Example
setWP 0x20000000 W S8 0xFF

3.2.1.38 sleep
Waits the given time (in milliseconds).

Syntax
sleep 

Parameter
Delay

Meaning
Amount of time to sleep in ms.

Example
sleep 200

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3.2.1.39 speed
This command sets the speed for communication with the CPU core.

Syntax
speed |auto|adaptive

Parameter
Freq
auto
adaptive

Meaning
Specifies the interface frequency in kHz.
Selects auto detection of JTAG speed.
Selects adaptive clocking as JTAG speed.

Example
speed 4000
speed auto

3.2.1.40 st
This command prints the current hardware status. Prints the current status of TCK,
TDI, TDO, TMS, TRES, TRST and the interface speeds supported by the target. Also
shows the Target Voltage.

Syntax
st

3.2.1.41 step (s)
Target needs to be halted before calling this command. Executes a single step on the
target. The instruction is overstepped even if it is breakpointed. Prints out the disassembly of the instruction to be stepped.

Syntax
step

3.2.1.42 unlock
This command unlocks a device which has been accidentally locked by malfunction of
user software.

Syntax
unlock 

Parameter

DeviceName

Meaning
Name of the device family to unlock. Supported Devices:
LM3Sxxx
Kinetis
EFM32Gxxx

Example
unlock Kinetis

3.2.1.43 usb
Closes any existing connection to J-Link and opens a new one via USB.
It is possible to select a specific J-Link by port number.

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Syntax
usb []

Parameter
Port

Meaning
Valid values: 0..3

Example
usb

3.2.1.44 verifybin
Verifies if the specified binary is already in the target memory at the specified
address.

Syntax
verifybin , 

Parameter
Filename
Addr

Meaning
Sample bin.
Start address of memory to verify.

Example
verifybin C:\Work\test.bin 0x0000000

3.2.1.45 w1
The command writes one single byte to the target system.

Syntax
w1 [:],  (hex)

Parameter
Zone
Addr
Data

Meaning
Name of memory zone to access.
Start address.
8-bits of data to write.

Example
w1 0x10, 0xFF

3.2.1.46 w2
The command writes a unit of 16-bits to the target system.

Syntax
w2 [:],  (hex)

Parameter
Zone
Addr
Data

Meaning
Name of memory zone to access.
Start address.
16-bits of data to write.

Example
w2 0x0, 0xFFFF

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3.2.1.47 w4
The command writes a unit of 32-bits to the target system.

Syntax
w4 [:],  (hex)

Parameter
Zone
Addr
Data

Meaning
Name of memory zone to access.
Start address.
32-bits of data to write.

Example
w4 0x0, 0xAABBCCFF

3.2.1.48 wreg
Writes into a register. The value is written into the register on CPU start.

Syntax
wreg , 

Parameter
RegName
Data

Meaning
Register to write to.
Data to write to the specified register.

Example
wreg R14, 0xFF

3.2.2

Command line options

J-Link Commander can be started with different command line options for test and
automation purposes. In the following, the command line options which are available
for J-Link Commander are explained.

-CommandFile
Selects a command file and starts J-Link Commander in batch mode. The batch mode
of J-Link Commander is similar to the execution of a batch file. The command file is
parsed line by line and one command is executed at a time.

Syntax
-CommandFile 

Example
See Using command files on page 82

-Device
Pre-selects the device J-Link Commander shall connect to. For some devices, J-Link
already needs to know the device at the time of connecting, since special handling is
required for some of them. For a list of all supported device names, please refer to
http://www.segger.com/jlink_supported_devices.html.

Syntax
-Device 

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Example
JLink.exe -Device STM32F103ZE

-If
Selects the target interface J-Link shall use to connect to the target. By default, JLink Commander first tries to connect to the target using the target interface which is
currently selected in the J-Link firmware. If connecting fails, J-Link Commander goes
through all target interfaces supported by the connected J-Link and tries to connect
to the device.

Syntax
-If 

Example
JLink.exe -If SWD

Additional information
Currently, the following target interfaces are supported:
•
•

JTAG
SWD

-IP
Selects IP as host interface to connect to J-Link. Default host interface is USB.

Syntax
-IP 

Example
JLink.exe -IP 192.168.1.17

Additional information
To select from a list of all available emulators on Ethernet, please use * as .

-SelectEmuBySN
Connect to a J-Link with a specific serial number via USB. Useful if multiple J-Links
are connected to the same PC and multiple instances of J-Link Commander shall run
and each connects to another J-Link.

Syntax
-SelectEmuBySN 

Example
JLink.exe -SelectEmuBySN 580011111

-Speed
Starts J-Link Commander with a given initial speed. Available parameters are "adaptive", "auto" or a freely selectable integer value in kHz. It is recommended to use
either a fixed speed or, if it is available on the target, adaptive speeds. Default interface speed is 100kHz.

Syntax
-Speed 

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Example
JLink.exe -Speed 4000

3.2.3

Using command files

J-Link commander can also be used in batch mode which allows the user to use JLink commander for batch processing and without user interaction. Please do not
confuse command file with J-Link script files (please refer to J-Link script files on
page 187 for more information about J-Link script files). When using J-Link commander in batch mode, the path to a command file is passed to it. The syntax in the
command file is the same as when using regular commands in J-Link commander
(one line per command). SEGGER recommends to always pass the device name via
command line option due some devices need special handling on connect/reset in
order to guarantee proper function.

Example
JLink.exe -device STM32F103ZE -CommanderScript C:\CommandFile.jlink

Contents of CommandFile.jlink:
si 1
speed 4000
r
h
loadbin C:\firmware.bin,0x08000000

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3.3

J-Link GDB Server
The GNU Project Debugger (GDB) is a freely available and open source debugger. It
can be used in command line mode, but is also integrated in many IDEs like emIDE
or Eclipse.
J-Link GDB Server is a remote server for GDB making it possible for GDB to connect
to and communicate with the target device via J-Link. GDB Server and GDB communicate via a TCP/IP connection, using the standard GDB remote protocol. GDB Server
receives the GDB commands, does the J-Link communication and replies with the
answer to GDB.
With J-Link GDB Server debugging in ROM and Flash of the target device is possible
and the Unlimited Flash Breakpoints can be used.
It also comes with some functionality not directly implemented in the GDB. These can
be accessed via monitor commands, sent directly via GDB, too.

The GNU Project Debugger (GDB) is a freely available debugger, distributed under
the terms of the GPL. The latest Unix version of the GDB is freely available from the
GNU committee under: http://www.gnu.org/software/gdb/download/
J-Link GDB Server is distributed free of charge.

3.3.1

J-Link GDB Server CL (Windows, Lunux, Mac)

J-Link GDB Server CL is a commandline-only version of the GDB Server.
The command line version is part of the Software and Documentation Package and
also included in the Linux and MAC versions.
Except for the missing GUI, J-Link GDB Server CL is identical to the normal version.
All sub-chapters apply to the command line version, too.

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3.3.2

J-Link software and documentation package

Debugging with J-Link GDB Server

With J-Link GDB Server programs can be debugged via GDB directly on the target
device like a normal application. The application can be loaded into RAM or flash of
the device.
Before starting GDB Server make sure a J-Link and the target device are connected.

3.3.2.1 Setting up GDB Server GUI version
The GUI version of GDB Server is part of the Windows J-Link Software Package
(JLinkGDBServer.exe).
When starting GDB Server a configuration dialog pops up letting you select the
needed configurations to connect to J-Link and the target.

All configurations can optionally be given in the command line options.
Note:
To make sure the connection to the target device can be established corretly, the device, as well as the interface and interface speed have to be given on
start of GDB Server, either via command line options or the configuration dialog.
If the target device option (-device) is given, the configuration dialog will not pop
up.

3.3.2.2 Setting up GDB Server CL version
The command line version of GDB Server is part of the J-Link Software Package for
all supported platforms.
On Windows its name is JLinkGDBServerCL.exe, on Linux and Mac it is JLinkGDBServer.

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Starting GDB Server on Windows
To start GDB Server CL on Windows, open the ’Run’ prompt (Windows-R) or a command terminal (cmd) and enter \JLinkGDBServerCL.exe
.

Starting GDB Server on Linux / Mac
To start GDB Server CL on Linux / Mac, open a terminal and call JLinkGDBServer


Command Line Options
When using GDB Server CL, at least the mandatory command line options have to be
given. Additional command line options can be given to change the default behavior
of GDB Server.
For more information about the available command line options, please refer to Command line options on page 104.

3.3.2.3 GDB Server user interface
The J-Link GDB Server’s user interface shows information about the debugging process and the target and allows to configure some settings during execution.

It shows following information:
•
•
•
•
•
•
•
•
•

The IP address of host running debugger.
Connection status of J-Link.
Information about the target core.
Measured target voltage.
Bytes that have been downloaded.
Status of target.
Log output of the GDB Server (optional, if Show log window is checked).
Initial and current target interface speed.
Target endianess.

These configurations can be made from inside GDB Server:
•
•
•
•
•
•

Localhost only: If checked only connections from 127.0.0.1 are accepted.
Stay on top
Show log window.
Generate logfile: If checked, a log file with the GDB <-> GDB Server <-> J-Link
communication will be created.
Verify download: If checked, the memory on the target will be verified after
download.
Init regs on start: If checked, the register values of the target will be set to a
reasonable value before on start of GDB Server.

3.3.2.4 Running GDB from different programs
We assume that you already have a solid knowledge of the software
tools used for building your application (assembler, linker, C compiler) and
especially the debugger and the debugger frontend of your choice. We
do not answer questions about how to install and use the chosen toolchain.

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GDB is included in many IDEs and most commonly used in connection with the GCC
compiler toolchain. This chapter shows how to configure some programs to use GDB
and connect to GDB Server. For more information about any program using GDB,
please refer to its user manual.

emIDE
emIDE is a full-featured, free and open source IDE for embedded development
including support for debugging with J-Link.
To connect to GDB Server with emIDE, the GDB Server configurations need to be set
in the project options at Project -> Properties... -> Debugger.
Select the target device you are using, the target connection, endianess and speed
and enter the additional GDB start commands.
The typically required GDB commands are:
#Initially reset the target
monitor reset
#Load the application
load

Other commands to set up the target (e.g. Set PC to RAM, initialize external flashes)
can be entered here, too.
emIDE will automatically start GDB Server on start of the debug session. If it does
not, or an older version of GDB Server starts, in emIDE click on JLink -> Run the
JLink-plugin configuration.

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The screenshot below shows a debug session in IDE. For download and more information about emIDE, please refer to http://emide.org.

Console
GDB can be used stand-alone as a console application.
To connect GDB to GDB Server enter target remote localhost:2331 into the running GDB. Within GDB all GDB commands and the remote monitor commands are
available. For more information about debugging with GDB refer to its online manual
available at http://sourceware.org/gdb/current/onlinedocs/gdb/.
A typical startup of a debugging session can be like:

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(gdb) file C:/temp/Blinky.elf
Reading symbols from C:/temp/Blinky.elf...done.
(gdb) target remote localhost:2331
Remote debugging using localhost:2331
0x00000000 in ?? ()
(gdb) monitor reset
Resetting target
(gdb) load
Loading section .isr_vector, size 0x188 lma 0x8000000
Loading section .text, size 0x568 lma 0x8000188
Loading section .init_array, size 0x8 lma 0x80006f0
Loading section .fini_array, size 0x4 lma 0x80006f8
Loading section .data, size 0x428 lma 0x80006fc
Start address 0x8000485, load size 2852
Transfer rate: 146 KB/sec, 570 bytes/write.
(gdb) break main
Breakpoint 1 at 0x800037a: file Src\main.c, line 38.
(gdb) continue
Continuing.
Breakpoint 1, main () at Src\main.c:38
38
Cnt = 0;
(gdb)

Eclipse (CDT)
Eclipse is an open source platform-independent software framework, which has typically been used to develop integrated development environment (IDE). Therefore
Eclipse can be used as C/C++ IDE, if you extend it with the CDT plug-in (http://
www.eclipse.org/cdt/).
CDT means "C/C++ Development Tooling" project and is designed to use the GDB as
default debugger and works without any problems with the GDB Server.
Refer to http://www.eclipse.org for detailed information about Eclipse.
Note:
We only support problems directly related to the GDB Server. Problems
and questions related to your remaining toolchain have to be solved on your own.

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3.3.3

Supported remote (monitor) commands

J-Link GDB Server comes with some functionalities which are not part of the standard
GDB. These functions can be called either via a gdbinit file passed to GDB Server or
via monitor commands passed directly to GDB, forwarding them to GDB Server.
To indicate to GDB to forward the command to GDB Server 'monitor' has to be
prepended to the call. For example a reset can be triggered in the gdbinit file with
"reset" or via GDB with "monitor reset".
Following remote commands are available:
Remote command
clrbp
cp15
device
DisableChecks
EnableChecks
flash breakpoints
getargs
go
halt
jtagconf
memU8
memU16
memU32
reg
regs
reset
semihosting breakOnError
semihosting enable
semihosting IOClient
semihosting ARMSWI
semihosting ThumbSWI
setargs
setbp
sleep
speed
step
SWO DisableTarget
SWO EnableTarget
SWO GetMaxSpeed
SWO GetSpeedInfo
waithalt
wice

Explanation
Removes an instruction breakpoint.
Reads or writes from/to cp15 register.
Select the specified target device.
Do not check if an abort occurred after memory read
(ARM7/9 only).
Check if an abort occurred after memory read (ARM7/9
only).
Enables/Disables flash breakpoints.
Get the arguments for the application.
Starts the target CPU.
Halts the target CPU.
Configures a JTAG scan chain with multiple devices on it.
Reads or writes a byte from/to given address.
Reads or writes a halfword from/to given address.
Reads or writes a word from/to given address.
Reads or writes from/to given register.
Reads and displays all CPU registers.
Resets and halts the target CPU.
Enable or disable halting the target on semihosting error.
Enables semihosting.
Set semihosting I/O to be handled via Telnet port or GDB.
Sets the SWI number used for semihosting in ARM mode.
Sets the SWI number used for semihosting in thumb
mode.
Set the arguments for the application.
Sets an instruction breakpoint at a given address.
Sleeps for a given time period.
Sets the JTAG speed of J-Link / J-Trace.
Performs one or more single instruction steps.
Undo target configuration for SWO and disable it in J-Link.
Configure target for SWO and enable it in J-Link.
Prints the maximum supported SWO speed for J-Link and
Target CPU.
Prints the available SWO speed and its minimum divider.
Waits for target to halt code execution.
Writes to given IceBreaker register.

Table 3.2: GDB remote commands

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Following remote commands are deprecated and only available for backward compability:
Remote command

Explanation
Select the specified target device.
Note:
Use
command
instead.
Select the target interface.

device

interface

line

option

-device

Note:
Use command line option -if instead.
Sets the JTAG speed of J-Link / J-Trace.
Note:
For the initial connection speed, use command line option -speed instead.

speed
Table 3.3: GDB remote commands

Note:

The remote commands are case-insensitive.

Note:

Optional parameters are set into square brackets.

Note:
The examples are described as follows:
Lines starting with ’#’ are comments and not used in GDB / GDB Server.
Lines starting with ’>’ are input commands from the GDB.
Lines starting with ’<’ is the output from GDB Server as printed in GDB.

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3.3.3.1 clrbp
Syntax
ClrBP []
or
ci []

Description
Removes an instruction breakpoint, where  is the handle of breakpoint to
be removed. If no handle is specified this command removes all pending breakpoints.

Example
> monitor clrbp 1

or
> monitor ci 1

3.3.3.2 cp15
Syntax
cp15 , , ,  [= ]

Description
Reads or writes from/to cp15 register. If  is specified, this command writes the
data to the cp15 register. Otherwise this command reads from the cp15 register. For
further information please refer to the ARM reference manual.

Example
#Read:
> monitor cp15 1, 2, 6, 7
< Reading CP15 register (1,2,6,7 = 0x0460B77D)
#Write:
> monitor cp15 1, 2, 6, 7 = 0xFFFFFFFF

3.3.3.3 device
Note:

Deprecated. Use command line option -device instead.

Syntax
device 

Description
Selects the specified target device. This is necessary for the connection and some
special handling of the device.
Note:
The device should be selected via commandline option -device when
starting GDB Server.

Example
> monitor device STM32F417IG
< Selecting device: STM32F417IG

3.3.3.4 DisableChecks
Syntax
DisableChecks

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Description
Disables checking if a memory read caused an abort (ARM7/9 devices only). On some
CPUs during the init sequence for enabling access to the internal memory (for example on the TMS470) some dummy reads of memory are required which will cause an
abort as long as the access-init is not completed.

3.3.3.5 EnableChecks
Syntax
EnableChecks

Description
Enables checking if a memory read caused an abort (ARM7/9 devices only). On some
CPUs during the init sequence for enabling access to the internal memory (for example on the TMS470) some dummy reads of memory are required which will cause an
abort as long as the access-init is not completed. The default state is: Checks
enabled.

3.3.3.6 flash breakpoints
Syntax
monitor flash breakpoints = 

Description
This command enables/disables the Flash Breakpoints feature.
By default Flash Breapkoints are enabled and can be used for evaluation.

Example
#Disable Flash Breakpoints:
> monitor flash breakpoints = 0
< Flash breakpoints disabled
#Enable Flash Breakpoins:
> monitor flash breakpoints = 1
< Flash breakpoints enabled

3.3.3.7 getargs
Syntax
getargs

Description
Get the currently set argument list which will be given to the application when calling
semihosting command SYS_GET_CMDLINE (0x15). The argument list is given as one
string.

Example
#No arguments set via setargs:
> monitor getargs
< No arguments.
#Arguments set via setargs:
> monitor getargs
< Arguments: test 0 1 2 arg0=4

3.3.3.8 go
Syntax
go

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Description
Starts the target CPU.

Example
> monitor go

3.3.3.9 halt
Syntax
halt

Description
Halts the target CPU.

Example
> monitor halt

3.3.3.10 interface
Note:

Deprecated. Use command line option -if instead.

Syntax
interface 

Description
Selects the target interface used by J-Link / J-Trace.

3.3.3.11 jtagconf
Syntax
jtagconf  

Description
Configures a JTAG scan chain with multiple devices on it.  is the sum of
IRLens of all devices closer to TDI, where IRLen is the number of bits in the IR
(Instruction Register) of one device.  is the number of devices closer to TDI.
For more detailed information of how to configure a scan chain with multiple devices
please refer to See “Determining values for scan chain configuration” on page 165..
Note:
To make sure the connection to the device can be established correctly, it
is recommended to configure the JTAG scan chain via command line options at the
start of GDB Server.

Example
#Select the second device, where there is 1 device in front with IRLen 4
> monitor jtagconf 4 1

3.3.3.12 memU8
Syntax
MemU8 
 [= ]

Description
Reads or writes a byte from/to a given address. If  is specified, this command writes the value to the given address. Otherwise this command reads from the
given address.

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Example
#Read:
> monitor memU8 0x50000000
< Reading from address 0x50000000 (Data = 0x04)
#Write:
> monitor memU8 0x50000000 = 0xFF
< Writing 0xFF @ address 0x50000000

3.3.3.13 memU16
Syntax
memU16 
 [= ]

Description
Reads or writes a halfword from/to a given address. If  is specified, this command writes the value to the given address. Otherwise this command reads from the
given address.

Example
#Read:
> monitor memU16 0x50000000
< Reading from address 0x50000000 (Data = 0x3004)
#Write:
> monitor memU16 0x50000000 = 0xFF00
< Writing 0xFF00 @ address 0x50000000

3.3.3.14 memU32
Syntax
MemU32 
 [= ]

Description
Reads or writes a word from/to a given address. If  is specified, this command writes the value to the given address. Otherwise this command reads from the
given address. This command is similar to the long command.

Example
#Read:
> monitor memU32 0x50000000
< Reading from address 0x50000000 (Data = 0x10023004)
#Write:
> monitor memU32 0x50000000 = 0x10023004
< Writing 0x10023004 @ address 0x50000000

3.3.3.15 reg
Syntax
reg  [= ]
or
reg  [= (
)]

Description
Reads or writes from/to given register. If  is specified, this command writes
the value into the given register. If 
 is specified, this command writes the
memory content at address 
 to register . Otherwise this command reads the given register.

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Example
#Write value to register:
> monitor reg pc
= 0x00100230
< Writing register (PC = 0x00100230)
#Write value from address to register:
> monitor reg r0
= (0x00000040)
< Writing register (R0 = 0x14813004)
#Read register value:
> monitor reg PC
< Reading register (PC = 0x00100230)

3.3.3.16 regs
Syntax
regs

Description
Reads all CPU registers.

Example
> monitor regs
< PC = 00100230, CPSR = 20000013 (SVC mode, ARM)
R0 = 14813004, R1 = 00000001, R2 = 00000001, R3 = 000003B5
R4 = 00000000, R5 = 00000000, R6 = 00000000, R7 = 00000000
USR: R8 =00000000, R9 =00000000, R10=00000000, R11 =00000000, R12 =00000000
R13=00000000, R14=00000000
FIQ: R8 =00000000, R9 =00000000, R10=00000000, R11 =00000000, R12 =00000000
R13=00200000, R14=00000000, SPSR=00000010
SVC: R13=002004E8, R14=0010025C, SPSR=00000010
ABT: R13=00200100, R14=00000000, SPSR=00000010
IRQ: R13=00200100, R14=00000000, SPSR=00000010
UND: R13=00200100, R14=00000000, SPSR=00000010

3.3.3.17 reset
Syntax
reset

Description
Resets and halts the target CPU. Make sure the device is selected prior to using this
command to make use of the correct reset strategy.

Add. information
There are different reset strategies for different CPUs. Moreover, the reset strategies
which are available differ from CPU core to CPU core. J-Link can perform various
reset strategies and always selects the best fitting strategy for the selected device.

Example
> monitor reset
< Resetting target

3.3.3.18 semihosting breakOnError
Syntax
semihosting breakOnerror 

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Description
Enables or disables halting the target at the semihosting breakpoint / in SVC handler
if an error occurred during a semihosting command, for example a bad file handle for
SYS_WRITE. The GDB Server log window always shows a warning in these cases.
breakOnError is disabled by default.

Example
#Enable breakOnError:
> monitor semihosting breakOnError 1

3.3.3.19 semihosting enable
Syntax
semihosting enable []

Description
Enables semihosting with the specified vector address. If no vector address is specified, the SWI vector (at address 0x8) will be used. GDBServer will output semihosting terminal data from the target via a separate connection on port 2333. Some IDEs
already establish a connection automatically on this port and show terminal data in a
specific window in the IDE.
For IDEs which do not support semihosting terminal output directly, the easiest way
to view semihosting output is to open a telnet connection to the GDBServer on port
2333. The connection on this port can be opened all the time as soon as GDBServer
is started, even before this remote command is executed.

Example
> monitor semihosting enable
< Semihosting enabled (VectorAddr = 0x08)

3.3.3.20 semihosting IOClient
Syntax
semihosting IOClient 

Description
GDB itself can handle (file) I/O operations, too. With this command it is selected
wheter to print output via TELNET port (2333), GDB, or both.
 is
•
•
•

1 for TELNET Client (Standard port 2333) (Default)
2 for GDB Client
or 3 for both (Input via GDB Client)

Example
#Select TELNET port as output source
> monitor semihosting ioclient 1
< Semihosting I/O set to TELNET Client
#Select GDB as output source
> monitor semihosting ioclient 2
< Semihosting I/O set to GDB Client
#Select TELNET port and GDB as output source
> monitor semihosting ioclient 3
< Semihosting I/O set to TELNET and GDB Client

3.3.3.21 semihosting ARMSWI
Syntax
semihosting ARMSWI 

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Description
Sets the SWI number used for semihosting in ARM mode. The default value for the
ARMSWI is 0x123456.

Example
> monitor semihosting ARMSWI 0x123456
< Semihosting ARM SWI number set to 0x123456

3.3.3.22 semihosting ThumbSWI
Syntax
semihosting ThumbSWI 

Description
Sets the SWI number used for semihosting in thumb mode. The default value for the
ThumbSWI is 0xAB

Example
> monitor semihosting ThumbSWI 0xAB
< Semihosting Thumb SWI number set to 0xAB

3.3.3.23 setargs
Syntax
setargs 

Description
Set arguments for the application, where all arguments are in one  separated by whitespaces.
The argument string can be gotten by the application via semihosting command
SYS_GET_CMDLINE (0x15).
Semihosting has to be enabled for getting the argumentstring (semihosting
enable). "monitor setargs" can be used before enabeling semihosting.
The maximum length for  is 512 characters.

Example
> monitor setargs test 0 1 2 arg0=4
< Arguments: test 0 1 2 arg0=4

3.3.3.24 setbp
Syntax
setbp  []

Description
Sets an instruction breakpoint at the given address, where  can be 0x03 for
ARM instruction breakpoints (Instruction width 4 Byte, mask out lower 2 bits) or
0x01 for THUMB instruction breakpoints (Instruction width 2 Byte, mask out lower
bit). If no mask is given, an ARM instruction breakpoint will be set.

Example
#Set a breakpoint (implicit for ARM instructions)
> monitor setbp 0x00000000
#Set a breakpoint on a THUMB instruction
> monitor setbp 0x00000100 0x01

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3.3.3.25 sleep
Syntax
sleep 

Description
Sleeps for a given time, where  is the time period in milliseconds to delay.
While sleeping any communication is blocked until the command returns after the
given period.

Example
> monitor sleep 1000
< Sleep 1000ms

3.3.3.26 speed
Note:
Deprecated. For setting the initial connection speed, use command line
option -speed instead.

Syntax
speed |auto|adaptive

Description
Sets the JTAG speed of J-Link / J-Trace. Speed can be either fixed (in kHz), automatic
recognition or adaptive. In general, Adaptive is recommended if the target has an
RTCK signal which is connected to the corresponding RTCK pin of the device (S-cores
only). For detailed information about the different modes, refer to JTAG Speed on
page 166.
The speed has to be set after selecting the interface, to change it from its default
value.

Example
> monitor speed auto
< Select auto target interface speed (8000 kHz)
> monitor speed 4000
< Target interface speed set to 4000 kHz
> monitor speed adaptive
< Select adaptive clocking instead of fixed JTAG speed

3.3.3.27 step
Syntax
step []
or
si []

Description
Performs one or more single instruction steps, where  is the number of
instruction steps to perform. If  is not specified only one instruction step
will be performed.

Example
> monitor step 3

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3.3.3.28 SWO DisableTarget
Syntax
SWO DisableTarget 

Description
Disables the output of SWO data on the target (Undoes changes from SWO EnableTarget) and stops J-Link to capture it.

Example
#Disable captureing SWO from stimulus ports 0 and 1
> monitor SWO DisableTarget 3
< SWO disabled succesfully.

3.3.3.29 SWO EnableTarget
Syntax
SWO EnableTarget   

Description
Configures the target to be able to output SWO data and starts J-Link to capture it.
CPU and SWO frequency can be 0 for auto-detection.
If CPUFreq is 0, J-Link will measure the current CPU speed.
If SWOFreq is 0, J-Link will use the highest available SWO speed for the selected /
measured CPU speed.
Note:
CPUFreq has to be the speed at which the target will be running when
doing SWO.
If the speed is different from the current speed when issuing CPU speed auto-detection, getting SWO data might fail.
SWOFreq has to be a quotient of the CPU and SWO speeds and their prescalers. To
get available speed, use SWO GetSpeedInfo.
PortMask can be a decimal or hexadecimal Value. Values starting with the Prefix "0x"
are handled hexadecimal.

Example
#Configure SWO for stimulus port 0, measure CPU frequency and calculate SWO frequency
> monitor SWO EnableTarget 0 0 1 0
< SWO enabled succesfully.
#Configure SWO for stimulus ports 0-2, fixed SWO frequency and measure CPU frequency
> monitor SWO EnableTarget 0 1200000 5 0
< SWO enabled succesfully.
#Configure SWO for stimulus ports 0-255, fixed CPU and SWO frequency
> monitor SWO EnableTarget 72000000 6000000 0xFF 0
< SWO enabled succesfully.

3.3.3.30 SWO GetMaxSpeed
Syntax
SWO GetMaxSpeed 

Description
Prints the maximum SWO speed supported by and matching both, J-Link and the
target CPU frequency.

Example
#Get SWO speed for 72MHz CPU speed
> monitor SWO GetMaxSpeed 72000000
< Maximum supported SWO speed is 6000000 Hz.
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3.3.3.31 SWO GetSpeedInfo
Syntax
SWO GetSpeedInfo

Description
Prints the base frequency and the minimum divider of the connected J-Link. With
this, the available SWO speeds for J-Link can be calculated and the matching one for
the target CPU frequency can be selected.

Example
> monitor SWO GetSpeedInfo
< Base frequency: 60000000Hz, MinDiv: 8
# Available SWO speeds for J-Link are: 7.5MHz, 6.66MHz, 6MHz, ...

3.3.3.32 waithalt
Syntax
waithalt 
or
wh 

Description
Waits for target to halt code execution, where  is the maximum time
period in milliseconds to wait.

Example
#Wait for halt with a timeout of 2 seconds
> monitor waithalt 2000

3.3.3.33 wice
Syntax
wice  
or
rmib  

Description
Writes to given IceBreaker register, where  is the data to write.

Example
> monitor wice 0x0C 0x100

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3.3.4

SEGGER-specific GDB protocol extensions

J-Link GDB Server implements some functionality which are not part of the standard
GDB remote protocol in general query packets. These SEGGER-specific general query
packets can be sent to GDB Server on the low-level of GDB, via maintanace commands, or with a custom client connected to GDB Server.
General query packets start with a ’q’. SEGGER-specific general queries are followed
by the identifier ’Segger’ plus the command group, the actual command and its
parameters.
Following SEGGER-specific general query packets are available:
Query Packet
qSeggerSTRACE:config
qSeggerSTRACE:start
qSeggerSTRACE:stop
qSeggerSTRACE:read

Explanation
Configure STRACE for usage.
Start STRACE.
Stop STRACE.
Read STRACE data.

Table 3.4: General Queries

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3.3.4.1 qSeggerSTRACE:config
Syntax
qSeggerSTRACE:config:

Parameter
ConfigString: String containing the configuration data separating settings by ’;’.

Description
Configures STRACE for usage. Configuration for example includes specification of the
trace port width to be used for tracing (1-bit, 2-bit, 4-bit (default) PortWidth=%Var%.
Note:
For more information please refer to UM08002 (J-Link SDK user guide),
chapter STRACE.

Response

ReturnValue is a 4 Byte signed integer.
>= 0
< 0

O.K.
Error.

Note:
ReturnValue is hex-encoded.
Return value 0 is "00000000", return value -1 is "FFFFFFFF".

3.3.4.2 qSeggerSTRACE:start
Syntax
qSeggerSTRACE:start

Description
Starts capturing of STRACE data.
Note:
For more information please refer to UM08002 (J-Link SDK user guide),
chapter STRACE.

Response

ReturnValue is a 4 Byte signed integer.
>= 0
< 0

O.K.
Error.

Note:
ReturnValue is hex-encoded.
Return value 0 is "00000000", return value -1 is "FFFFFFFF".

3.3.4.3 qSeggerSTRACE:stop
Syntax
qSeggerSTRACE:stop

Description
Stops capturing of STRACE data.
Note:
For more information please refer to UM08002 (J-Link SDK user guide),
chapter STRACE.
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Response

ReturnValue is a 4 Byte signed integer.
>= 0
< 0

O.K.
Error.

Note:
ReturnValue is hex-encoded.
Return value 0 is "00000000", return value -1 is "FFFFFFFF".

3.3.4.4 qSeggerSTRACE:read
Syntax
qSeggerSTRACE:read:

Parameter
NumItems: Maximum number of trace data (addresses) to be read. Hexadecimal.

Description
Read the last recently called instruction addresses. The addresses are returned LIFO,
meaning the last recent address is returned first.
Note:
For more information please refer to UM08002 (J-Link SDK user guide),
chapter STRACE.

Response
[...]
ReturnValue is a 4 Byte signed integer.
>= 0
< 0

Number of items read.
Error.

ItemN is a 4 Byte unsigned integer.
0x00000000 - 0xFFFFFFFF Address of the executed instruction
Note:
ReturnValue and ItemN are hex-encoded.
e.g. 3 Items read: 0x08000010, 0x08000014, 0x08000018
Response will be: 00000003080000100800001408000018

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3.3.5

J-Link software and documentation package

Command line options

There are several command line options available for the GDB Server which allow
configuration of the GDB Server before any connection to a J-Link is attempted or
any connection from a GDB client is accepted.
Note:
Using GDB Server CL, device, interface, endian and speed are mandatory
options to correctly connect to the target, and should be given before connection via
GDB. Using GDB Server GUI the mandatory options can also be selected in the configuration dialog.
Command line option

Explanation
Select
Select
Select
Select

-device
-endian
-if
-speed

the
the
the
the

connected target device.
device endianness.
interface to connect to the target.
target communication speed.

Table 3.5: Mandatory command line options

Note:
Using multiple instances of GDB Server, setting custom values for port,
SWOPort and TelnetPort is necessary.
Command line option
-port
-swoport
-telnetport

Explanation
Select the port to listen for GDB clients.
Select the port to listen for clients for SWO RAW output.
Select the port to listen for clients for printf output.

Table 3.6: Port selection command line options

The GDB Server GUI version uses persistent settings which are saved across different
instances and sessions of GDB Server. These settings can be toggled via the checkboxes in the GUI.
Note:

GDB Server CL always starts with the settings marked as default.

For GUI and CL, the settings can be changed with following command line options.
For all persistent settings there is a pair of options to enable or disable the feature.
Command line option
-ir
-noir
-localhostonly
-nolocalhostonly
-logtofile
-nologtofile
-halt
-nohalt
-silent
-nosilent
-stayontop
-nostayontop
-timeout
-notimeout
-vd
-novd

Explanation
Initialize the CPU registers on start of GDB Server. (Default)
Do not initialize CPU registers on start of GDB Server.
Allow only localhost connections (Windows default)
Allow connections from outside localhost (Linux default)
Generate a GDB Server log file.
Do not generate a GDB Server log file. (Default)
Halt the target on start of GDB Server.
Do not halt the target on start of GDB Server. (Default)
Do not show log output.
Show log output. (Default)
Set the GDB Server GUI to be the topmost window.
Do not be the topmost window. (Default)
Set the time after which the target has to be connected.
Set infinite timeout for target connection.
Verify after downloading.
Do not verify after downloading. (Default)

Table 3.7: Persistent command line options

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Following additional command line options are available. These options are temporary for each start of GDB Server.
Command line option
-jtagconf
-log
-singlerun
-scriptfile
-select
-settingsfile
-strict
-x
-xc
-cpu

Explanation
Configures a JTAG scan chain with multiple devices on it.
Logs the GDB Server communication to a specific file.
Starts GDB Server in single run mode.
Uses a J-Link scriptfile.
Selects the interface to connect to J-Link (USB/IP).
Selects the J-Link Settings File.
Starts GDB Server in strict mode.
Executes a gdb file on first connection.
Executes a gdb file on every connection.
Selects the CPU core. Deprecated, use -device instead.

Table 3.8: General command line options

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3.3.5.1 -cpu
Description
Pre-select the CPU core of the connected device, so the GDB Server already knows
the register set, even before having established a connection to the CPU.
Note:
Deprecated, please use -device instead. Anyhow, it does not hurt if this
option is set, too.

Syntax
-CPU 

Example
jlinkgdbserver -CPU ARM7_9

Add. information
The following table lists all valid values for :

CPU_FAMILY_ARM7_9
CPU_FAMILY_CORTEX_A_R
CPU_FAMILY_CORTEX_M
CPU_FAMILY_RX600

Supported CPU cores
Pre-select
Pre-select
Pre-select
Pre-select

ARM7 and ARM9 as CPU cores.
Cortex-A and Cortex-R as CPU cores.
Cortex-M as CPU core.
Renesas RX600 as CPU core.

Table 3.9: GDB allowed values for CPUCore

3.3.5.2 -device
Description
Tells GDBServer to which device J-Link is connected before the connect sequence is
actually performed. It is recommended to use the command line option to select the
device instead of using the remote command since for some devices J-Link already
needs to know the device at the time of connecting to it since some devices need
special connect sequences (e.g. devices with TI ICEPick modules). In such cases, it is
not possible to select the device via remote commands since they are configured
after the GDB client already connected to GDBServer and requested the target registers which already requires a connection to the target.
Note:
Using GDB Server CL this option is mandatory to correctly connect to the
target, and should be given before connection via GDB.

Syntax
-device 

Example
jlinkgdbserver -device AT91SAM7SE256

Add. information
For a list of all valid values for , please refer to http://www.segger.com/jlink_supported_devices.html.

3.3.5.3 -endian
Description
Sets the endianess of the target where endianess can either be "little" or "big".
Note:
Using GDB Server CL this option is mandatory to correctly connect to the
target, and should be given before connection via GDB.

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Syntax
-endian 

Example
jlinkgdbserver -endian little

3.3.5.4 -if
Description
Selects the target interface which is used by J-Link to connect to the device. The
default value is JTAG.
Note:
Using GDB Server CL this option is mandatory to correctly connect to the
target, and should be given before connection via GDB.

Syntax
-if 

Example
jlinkgdbserver -if SWD

Add. information
Currently, the following values are accepted for :
•
•
•
•

JTAG
SWD
FINE
2-wire-JTAG-PIC32

3.3.5.5 -ir
Description
Initializes the CPU register with default values on startup.
Note:
For the GUI version, this setting is persistent for following uses of GDB
Server until changed via -noir or the GUI.

Example
jlinkgdbserver -ir

3.3.5.6 -jtagconf
Syntax
-jtagconf ,

Description
Configures a JTAG scan chain with multiple devices on it.  is the sum of
IRLens of all devices closer to TDI, where IRLen is the number of bits in the IR
(Instruction Register) of one device.  is the number of devices closer to TDI.
For more detailed information of how to configure a scan chain with multiple devices
please refer to See “Determining values for scan chain configuration” on page 165..

Example
#Select the second device, where there is 1 device in front with IRLen 4
jlinkgdbserver -jtagconf 4,1

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3.3.5.7 -localhostonly
Description
Starts the GDB Server with the option to listen on localhost only (This means that
only TCP/IP connections from localhost are accepted) or on any IP address. To allow
remote debugging (connecting to GDBServer from another PC), deactivate this
option.
If no parameter is given, it will be set to 1 (active).
Note:
For the GUI version, this setting is persistent for following uses of GDB
Server until changed via command line option or the GUI.

Syntax
-LocalhostOnly 

Example
jlinkgdbserver -LocalhostOnly 0 //Listen on any IP address (Linux/MAC default)
jlinkgdbserver -LocalhostOnly 1 //Listen on localhost only (Windows default)

3.3.5.8 -log
Description
Starts the GDB Server with the option to write the output into a given log file.
The file will be created if it does not exist. If it exists the previous content will be
removed. Paths including spaces need to be set between quotes.

Syntax
-log 

Example
jlinkgdbserver -log “C:\my path\to\file.log”

3.3.5.9 -logtofile
Description
Starts the GDB Server with the option to write the output into a log file.
If no file is given via -log, the log file will be created in the GDB Server application
directory.
Note:
For the GUI version, this setting is persistent for following uses of GDB
Server until changed via -nologtofile or the GUI.

Syntax
-logtofile

Example
jlinkgdbserver -logtofile
jlinkgdbserver -logtofile -log “C:\my path\to\file.log”

3.3.5.10 -halt
Description
Halts the target after connecting to it on start of GDB Server.
For most IDEs this option is mandatory since they rely on the target to be halted
after connecting to GDB Server.
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Note:
For the GUI version, this setting is persistent for following uses of GDB
Server until changed via -nohalt or the GUI.

Syntax
-halt

Example
jlinkgdbserver -halt

3.3.5.11 -noir
Description
Do not initialize the CPU registers on startup.
Note:
For the GUI version, this setting is persistent for following uses of GDB
Server until changed via -ir or the GUI.

Syntax
-noir

3.3.5.12 -nolocalhostonly
Description
Starts GDB Server with the option to allow remote connections (from outside localhost).
Same as -localhostonly 0
Note:
For the GUI version, this setting is persistent for following uses of GDB
Server until changed via command line option or the GUI.

Syntax
-nolocalhostonly

3.3.5.13 -nologtofile
Description
Starts the GDB Server with the option to not write the output into a log file.
Note:
For the GUI version, this setting is persistent for following uses of GDB
Server until changed via -nologtofile or the GUI.
Note:
When this option is used after -log, no log file will be generated, when -log
is used after this option, a log file will be generated and this setting will be overridden.

Syntax
-nologtofile

Example
jlinkgdbserver -nologtofile

// Will not generate a log file

jlinkgdbserver -nologtofile -log “C:\pathto\file.log” // Will generate a log file
jlinkgdbserver -log “C:\pathto\file.log” -nologtofile // Will not generate a log file

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3.3.5.14 -nohalt
Description
When connecting to the target after starting GDB Server, the target is not explicitly
halted and the CPU registers will not be inited.
After closing all GDB connections the target is started again and continues running.
Some IDEs rely on the target to be halted after connect. In this case do not use nohalt, but -halt.
Note:
For the GUI version, this setting is persistent for following uses of GDB
Server until changed via -halt or the GUI.

Syntax
-nohalt

Example
jlinkgdbserver -nohalt

3.3.5.15 -nosilent
Description
Starts the GDB Server in non-silent mode. All log window messages will be shown.
Note:
For the GUI version, this setting is persistent for following uses of GDB
Server until changed via command line option or the GUI.

Syntax
-nosilent

3.3.5.16 -nostayontop
Description
Starts the GDB Server in non-topmost mode. All windows can be placed above it.
Note:

For the CL version this setting has no effect.

Note:
For the GUI version, this setting is persistent for following uses of GDB
Server until changed via command line option or the GUI.

Syntax
-nostayontop

3.3.5.17 -notimeout
Description
GDB Server automatically closes after a timout of 5 seconds when no target voltage
can be measured or connection to target fails.
This command line option prevents GDB Server from closing, to allow connecting a
target after starting GDB Server.
Note:
The recommended order is to power the target, connect it to J-Link and
then start GDB Server.

Syntax
-notimeout

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3.3.5.18 -novd
Description
Do not explicitly verify downloaded data.
Note:
For the GUI version, this setting is persistent for following uses of GDB
Server until changed via command line option or the GUI.

Syntax
-vd

3.3.5.19 -port
Description
Starts GDB Server listening on a specified port. This option overrides the default listening port of the GDB Server. The default port is 2331.
Note:
Using multiple instances of GDB Server, setting custom values for this
option is necessary.

Syntax
-port 

Example
jlinkgdbserver -port 2345

3.3.5.20 -scriptfile
Description
Passes the path of a J-Link script file to the GDB Server. This scriptfile is executed
before the GDB Server starts the debugging / identifying communication with the target. J-Link scriptfiles are mainly used to connect to targets which need a special connection sequence before communication with the core is possible. For more
information about J-Link script files, please refer to J-Link script files on page 187.

Syntax
-scriptfile 

Example
-scriptfile “C:\My Projects\Default.JLinkScript“

3.3.5.21 -select
Description
Specifies the host interface to be used to connect to J-Link. Currently, USB and TCP/
IP are available.

Syntax
-select =/

Example
jlinkgdbserver -select usb=580011111
jlinkgdbserver -select ip=192.168.1.10

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Additional information
For backward compatibility, when USB is used as interface serial numbers from 0-3
are accepted as USB=0-3 to support the old method of connecting multiple J-Links to
a PC. This method is no longer recommended to be used. Please use the “connect via
emulator serial number“ method instead.

3.3.5.22 -settingsfile
Description
Select a J-Link settings file to be used for the target device. The settings fail can contain all configurable options of the Settings tab in J-Link Control panel.

Syntax
-SettingsFile 

Example
jlinkgdbserver -SettingsFile "C:\Temp\GDB Server.jlink"

3.3.5.23 -silent
Description
Starts the GDB Server in silent mode. No log window messages will be shown.
Note:
For the GUI version, this setting is persistent for following uses of GDB
Server until changed via command line option or the GUI.

Syntax
-silent

3.3.5.24 -singlerun
Description
Starts GDB Server in single run mode. When active, GDB Server will close when all
client connections are closed.
In normal run mode GDB Server will stay open and wait for new connections.
When started in single run mode GDB Server will close immediately when connecting
to the target fails. Make sure it is powered and connected to J-Link before starting
GDB Server.

Syntax
-s
-singlerun

3.3.5.25 -speed
Description
Starts GDB Server with a given initial speed.
Available parameters are “adaptive”, “auto” or a freely selectable integer value in
kHz. It is recommended to use either a fixed speed or, if it is available on the target,
adaptive speeds.
Note:
Using GDB Server CL this option is mandatory to correctly connect to the
target, and should be given before connection via GDB.

Syntax
-speed 

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Example
jlinkgdbserver -speed 2000

3.3.5.26 -stayontop
Description
Starts the GDB Server in topmost mode. It will be placed above all non-topmost windows and maintains it position even when it is deactivated.
Note:

For the CL version this setting has no effect.

Note:
For the GUI version, this setting is persistent for following uses of GDB
Server until changed via command line option or the GUI.

Syntax
-stayontop

3.3.5.27 -timeout
Description
Set the timeout after which the target connection has to be established. If no connection could be established GDB Server will close.
The default timeout is 5 seconds for the GUI version and 0 for the command line version.
Note:
The recommended order is to power the target, connect it to J-Link and
then start GDB Server.

Syntax
-timeout 

Example
Allow target connection within 10 seconds.
jlinkgdbserver -timeout 10000

3.3.5.28 -strict
Description
Starts GDB Server in sctrict mode. When strict mode is active GDB Server checks the
correctness of settings and exits in case of a failure.
Currently the device name is checked. If no device name is given or the device is
unknown to the J-Link, GDB Server exits instead of selecting "Unspecified" as device
or showing the device selection dialog.

Syntax
- strict

Example
Following executions of GDB Server (CL) will cause exit of GDB Server.
jlinkgdbserver -strict -device UnknownDeviceName
jlinkgdbservercl -strict

Following execution of GDB Server will show the device selction dialog under Windows or select "Unspecified" directly under Linux / OS X.
jlinkgdbserver -device UnknownDeviceName

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3.3.5.29 -swoport
Description
Set up port on which GDB Server should listen for an incoming connection that reads
the SWO data from GDB Server. Default port is 2332.
Note:
Using multiple instances of GDB Server, setting custom values for this
option is necessary.

Syntax
-SWOPort 

Example
jlinkgdbserver -SWOPort 2553

3.3.5.30 -telnetport
Description
Set up port on which GDB Server should listen for an incoming connection that gets
target’s printf data (Semihosting and anylized SWO data). Default port is 2333.
Note:
Using multiple instances of GDB Server, setting custom values for this
option is necessary.

Syntax
-TelnetPort 

Example
jlinkgdbserver -TelnetPort 2554

3.3.5.31 -vd
Description
Verifys the data after downloading it.
Note:
For the GUI version, this setting is persistent for following uses of GDB
Server until changed via command line option or the GUI.

Syntax
-vd

3.3.5.32 -x
Description
Starts the GDB Server with a gdbinit (configuration) file. In contrast to the -xc command line option the GDB Server runs the commands in the gdbinit file once only
direct after the first connection of a client.

Syntax
-x 

Example
jlinkgdbserver -x C:\MyProject\Sample.gdb

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3.3.5.33 -xc
Description
Starts the GDB Server with a gdbinit (configuration) file. GDB Server executes the
commands specified in the gdbinit file with every connection of a client / start of a
debugging session.

Syntax
-xc 

Example
jlinkgdbserver -xc C:\MyProject\Sample.gdb

3.3.6

Program termination

J-Link GDB Server is normally terminated by a close or Ctrl-C event. When the single
run mode is active it will also close when an error occurred during start or after all
connections to GDB Server are closed.
On termination GDB Server will close all connections and disconnect from the target
device, letting it run.

3.3.6.1 Exit codes
J-Link GDB Server terminates with an exit code indicating an error by a non-zero exit
code.
The following table describes the defined exit codes of GDB Server.
Exit code
0
-1
-2
-3
-4
-5
-6
-7

Description
No error. GDB Server closed normally.
Unknown error. Should not happen.
Failed to open listener port (Default: 2331)
Could not connect to target. No target voltage detected or
connection failed.
Failed to accept a connection from GDB.
Failed to parse the command line options, wrong or missing
command line parameter.
Unknown or no device name set.
Failed to connect to J-Link.

Table 3.10: GDB Server exit codes

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3.4

J-Link software and documentation package

J-Link Remote Server
J-Link Remote Server allows using J-Link / J-Trace remotely via TCP/IP. This enables
you to connect to and fully use a J-Link / J-Trace from another computer. Performance is just slightly (about 10%) lower than with direct USB connection.

The J-Link Remote Server also accepts commands which are passed to the J-Link
Remote Server via the command line.

3.4.1

List of available commands

The table below lists the commands accepted by the J-Link Remote Server
Command
port
SelectEmuBySN

Description
Selects the IP port on which the J-Link Remote Server is
listening.
Selects the J-Link to connect to by its Serial Number.

Table 3.11: Available commands

3.4.1.1 port
Syntax
-port 

Example
To start the J-Link Remote Server listening on port 19021 the command should look
as follows:
-port 19021

3.4.1.2 SelectEmuBySN
Syntax
-SelectEmuBySN 

Example
To select the emulator with Serial Number 268000000 the command should look as
follows:
-SelectEmuBySN 268000000

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3.4.2

Tunneling mode

The Remote server provides a tunneling mode which allows remote connection to a JLink / J-Trace from any computer, even from outside the local network.
To give access to a J-Link neither a remote desktop or vpn connection nor changing
some difficult firewall settings is necessary.
When started in tunneling mode the Remote server connects to the SEGGER tunnel
server via port 19020 and registers with its serial number. To connect to the J-Link
from the remote computer an also simple connection to tunnel: can be
established and the debugger is connected to the J-Link.

Target
LAN

Debugger
LAN
SEGGER
tunnel
server

TCP/IPServer

PC

Debugger

Internet

PC

USB/Ethernet

J-Link

JTAG

Target
CPU

Example scenario
A device vendor is developing a new device which shall be supported by J-Link.
Because there is only one prototype, a shipment to SEGGER is not possible.
Instead the vendor can connect the device via J-Link to a local computer and start
the Remote server in tunneling mode. He then gives the serial number of the J-Link
to an engineer at SEGGER.
The engineer at SEGGER can use J-Link Commander or a debugger to test and debug
the new device without the need to have the device on his desk.

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Start J-Link Remote Server in tunneling mode

Connect to the J-Link / J-Trace via J-Link commander
J-Link Commander can be used to verify a connection to the J-Link can be established as follows:
Start J-Link Commander
From within J-Link Commander enter
ip tunnel:
If the connection was successful it should look like in this screenshot.

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Troubleshooting
Problem
Remote server cannot connect to tunnel
server.

J-Link Commander cannot connect to
tunnel server.

Solution
1. Make sure the Remote server is not
blocked by any firewall.
2. Make sure port 19020 is not blocked
by any firewall.
3. Contact network admin.
1. Make sure Remote server is started
correctly.
2. Make sure the entered serial number is
correct.
3. Make sure port 19020 is not blocked
by any firewall. Contact network admin.

Table 3.12:

To test whether a connection to the tunnel server can be established or not a network
protocol analyzer like Wireshark can help.
The network transfer of a successful connection should look like:

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J-Mem Memory Viewer
J-Mem displays memory contents of target systems and allows modifications of RAM
and SFRs (Special Function Registers) while the target is running. This makes it possible to look into the memory of a target system at run-time; RAM can be modified
and SFRs can be written. You can choose between 8/16/32-bit size for read and write
accesses. J-Mem works nicely when modifying SFRs, especially because it writes the
SFR only after the complete value has been entered.

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3.6

J-Flash
J-Flash is an application to program data images to the flash of a target device. With
J-Flash the internal flash of all J-Link supported devices can be programmed, as well
as common external flashes connected to the device. Beside flash programming all
other flash operations like erase, blank check and flash content verification can be
done.
J-Flash requires an additional license from SEGGER to enable programming. For
license keys, as well as evaluation licenses got to http://www.segger.com or contact
us directly.

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J-Link software and documentation package

J-Link SWO Viewer
Free-of-charge utility for J-Link. Displays the terminal output of the target using the
SWO pin. The stimulus port(s) from which SWO data is received can be chosen by
using the port checkboxes 0 to 31. Can be used in parallel with a debugger or standalone. This is especially useful when using debuggers which do not come with built-in
support for SWO such as most GDB / GDB+Eclipse based debug environments.

3.7.0.1 J-Link SWO Viewer CL
Command line-only version of SWO Viewer. All commands avaible for J-Link SWO
Viewer can be used with J-Link SWO Viewer Cl. Similar to the GUI Version,J-Link
SWO Viewer Cl asks for a device name or CPU clock speed at startup to be able to
calculate the correct SWO speed or to connect to a running J-Link GDB Server

Using the syntax given below(List of available command line options), you can
directly start J-Link SWO Viewer Cl with parameters.

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3.7.1

Usage

J-Link SWO Viewer is available via the start menu.
It asks for a device name or CPU clock speed at startup to be able to calculate the
correct SWO speed or to connect to a running J-Link GDB Server.

When running in normal mode J-Link SWO Viewer automatically performs the necessary initialization to enable SWO output on the target, in GDB Server mode the initialization has to be done by the debugger.

3.7.2

List of available command line options

J-Link SWO Viewer can also be controlled from the command line if used in a automated test environment etc.
When passing all necessary information to the utility via command line, the configuration dialog at startup is suppressed. Minimum information needed by J-Link SWO
Viewer is the device name (to enable CPU frequency auto detection) or the CPU clock
speed.
The table below lists the commands accepted by the J-Link SWO Viewer.
Command
cpufreq
device
itmmask
itmport
outputfile
settingsfile
swofreq

Description
Select the CPU frequency.
Select the target device.
Selects a set of itm stimulus ports which should be used
to listen to.
Selects a itm stimulus port which should be used to listen
to.
Print the output of SWO Viewer to the selected file.
Specify a J-Link settings file.
Select the CPU frequency.

Table 3.13: Available command line options

3.7.2.1 cpufreq
Defines the speed in Hz the CPU is running at. If the CPU is for example running at
96 MHz, the command line should look as below.

Syntax
-cpufreq 

Example
-cpufreq 96000000

3.7.2.2 device
Select the target device to enable the CPU frequency auto detection of the J-Link
DLL. To select a ST STM32F207IG as target device, the command line should look as
below.
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For a list of all supported device names, please refer to 

Syntax
-device 

Example
-deivce STM32F207IG

3.7.2.3 itmmask
Defines a set of stimulusports from which SWO data is received and displayed by
SWO Viewer.
If itmmask is given, itmport will be ignored.

Syntax
-itmmask 

Example
Listen on ports 0 and 2
-itmmask 0x5

3.7.2.4 itmport
Defines the stimulus port from which SWO data is received and displayed by the SWO
Viewer. Default is stimulus port 0. The command line should look as below.

Syntax
-itmport 

Example
-itmport 0

3.7.2.5 outputfile
Define a file to which the output of SWO Viewer is printed.

Syntax
-outputfile 

Example
-outputfile "C:\Temp\Output.log"

3.7.2.6 settingsfile
Select a J-Link settings file to use for the target device.

Syntax
-settingsfile 

Example
-settingsfile "C:\Temp\Settings.jlink"

3.7.2.7 swofreq
Define the SWO frequency that shall be used by J-Link SWO Viewer for sampling
SWO data.
Usually not necessary to define since optimal SWO speed is calculated automatically
based on the CPU frequency and the capabilities of the connected J-Link.

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Syntax
-swofreq 

Example
-swofreq 6000

3.7.3

Configure SWO output after device reset

In some situations it might happen that the target application is reset and it is
desired to log the SWO output of the target after reset during the booting process.
For such situations, the target application itself needs to initialize the CPU for SWO
output, since the SWO Viewer is not restarted but continuously running.

Example code for enabling SWO out of the target application
#define
#define
#define
#define
#define
#define
#define

ITM_ENA
ITM_TPR
ITM_TCR
ITM_LSR
DHCSR
DEMCR
TPIU_ACPR

(*(volatile
(*(volatile
(*(volatile
(*(volatile
(*(volatile
(*(volatile
(*(volatile

unsigned
unsigned
unsigned
unsigned
unsigned
unsigned
unsigned

int*)0xE0000E00)
int*)0xE0000E40)
int*)0xE0000E80)
int*)0xE0000FB0)
int*)0xE000EDF0)
int*)0xE000EDFC)
int*)0xE0040010)

// ITM Enable
// Trace Privilege Register
// ITM Trace Control Reg.
// ITM Lock Status Register
// Debug register
// Debug register
// Async Clock
\
// presacler register
#define TPIU_SPPR (*(volatile unsigned int*)0xE00400F0) // Selected Pin Protocol \
// Register
#define DWT_CTRL
(*(volatile unsigned int*)0xE0001000) // DWT Control Register
#define FFCR
(*(volatile unsigned int*)0xE0040304) // Formatter and flush
\
// Control Register
U32 _ITMPort = 0; // The stimulus port from which SWO data is received and displayed.
U32 TargetDiv = 1;// Has to be calculated according to
\
// the CPU speed and the output baud rate
static void _EnableSWO() {
U32 StimulusRegs;
//
// Enable access to SWO registers
//
DEMCR |= (1 << 24);
ITM_LSR = 0xC5ACCE55;
//
// Initially disable ITM and stimulus port
// To make sure that nothing is transferred via SWO
// when changing the SWO prescaler etc.
//
StimulusRegs = ITM_ENA;
StimulusRegs &= ~(1 << _ITMPort);
ITM_ENA = StimulusRegs;
ITM_TCR
= 0;
//
// Initialize SWO (prescaler, etc.)
//
TPIU_SPPR = 0x00000002;
TPIU_ACPR = TargetDiv - 1;
ITM_TPR
= 0x00000000;
DWT_CTRL
= 0x400003FE;
FFCR
= 0x00000100;
//
// Enable ITM and stimulus port
//
ITM_TCR
= 0x1000D;
ITM_ENA
= StimulusRegs | (1 << _ITMPort);
}

3.7.4

// Disable ITM stimulus port
// Disable ITM

// Select NRZ mode
// Example: 72/48 = 1,5 MHz

// Enable ITM
// Enable ITM stimulus port

Target example code for terminal output

/*********************************************************************
*
SEGGER MICROCONTROLLER GmbH & Co KG
*
*
Solutions for real time microcontroller applications
*
**********************************************************************
*
*
*
(c) 2012-2013 SEGGER Microcontroller GmbH & Co KG
*
*
*
*
www.segger.com
Support: support@segger.com
*
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*
*
**********************************************************************
---------------------------------------------------------------------File
: SWO.c
Purpose : Simple implementation for output via SWO for Cortex-M processors.
It can be used with any IDE. This sample implementation ensures that
output via SWO is enabled in order to gurantee that the application
does not hang.
-------*/

END-OF-HEADER

---------------------------------------------

/*********************************************************************
*
*
Prototypes (to be placed in a header file such as SWO.h)
*/
void SWO_PrintChar (char c);
void SWO_PrintString(const char *s);
/*********************************************************************
*
*
Defines for Cortex-M debug unit
*/
#define ITM_STIM_U32 (*(volatile unsigned int*)0xE0000000) // STIM word access
#define ITM_STIM_U8 (*(volatile
char*)0xE0000000) // STIM Byte access
#define ITM_ENA
(*(volatile unsigned int*)0xE0000E00) // ITM Enable Reg.
#define ITM_TCR
(*(volatile unsigned int*)0xE0000E80) // ITM Trace Control Reg.
/*********************************************************************
*
*
SWO_PrintChar()
*
* Function description
*
Checks if SWO is set up. If it is not, return,
*
to avoid program hangs if no debugger is connected.
*
If it is set up, print a character to the ITM_STIM register
*
in order to provide data for SWO.
* Parameters
*
c:
The Chacracter to be printed.
* Notes
*
Additional checks for device specific registers can be added.
*/
void SWO_PrintChar(char c) {
//
// Check if ITM_TCR.ITMENA is set
//
if ((ITM_TCR & 1) == 0) {
return;
}
//
// Check if stimulus port is enabled
//
if ((ITM_ENA & 1) == 0) {
return;
}
//
// Wait until STIMx is ready,
// then send data
//
while ((ITM_STIM_U8 & 1) == 0);
ITM_STIM_U8 = c;
}

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/*********************************************************************
*
*
SWO_PrintString()
*
* Function description
*
Print a string via SWO.
*
*/
void SWO_PrintString(const char *s) {
//
// Print out character per character
//
while (*s) {
SWO_PrintChar(*s++);
}
}

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3.8

J-Link software and documentation package

J-Scope
J-Scope is a free-of-charge software to analyze and visualize data on a microcontroller in real-time, while the target is running.

3.8.1

Getting Started

J-Scope is part of the J-Link Software and Documentation Package (JScope.exe).

Preparation
Before starting J-Scope make sure you have an elf-file of your target application and
the target is running the application. The application can either be flashed with JFlash or directly ran from an IDE.
Start J-Scope by double-clicking on the executable.
The Project Configuration Dialog will open.

3.8.1.1 Set up Connection
Attach to a running instance

J-Scope can be used alongside other applications, e.g. a debugger, which are connected to J-Link and share the connection to the J-Link. If J-Scope is used in this
mode select "Existing Session" as connection type.
All Target options will be disabled, as they are already determined by the running
session.
Note:
In attach mode J-Scope will connect to J-Link indirectly via another application connected to J-Link. J-Scope can only be used while the connection is active,
e.g. a debug session is running. It is the applications responsibility to set up the target and J-Link connection and to manage target execution.

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Connecting to J-Link

If J-Scope is used in standalone mode, opening a dedicated connection to J-Link,
choose "USB" or "TCP/IP" as connection type and optionally enter the serial number
or the IP of the J-Link to connect to a specific J-Link.
For most targets, the target configuration does not have to be specified. If there are
any problems, select your target device and configure the interface accordingly.

3.8.1.2 Select application file and symbols
In the configuration dialog, select your elf-file and click OK. The Symbol Selection
Dialog will open.
Select the symbols of your application, you want to watch and analyze. Click OK to
finalize the setup.

3.8.1.3 Start sampling
Data sampling can be started via the record-button (red dot) in the toolbar. On start
of sampling, the connection to J-Link or running session will be established.

3.8.2

Project Files

The project configuration, which are the J-Link connection settings, the elf-application file and the configuration of the selected symbols can be saved to a J-Scope
project file (.jscope).
J-Scope projects can be used for further sessions and exchanged between different
users.

3.8.3

Exporting Sampled Data

3.8.3.1 Export to CSV
The sampled data which is currently in the buffer can be exported into CSV format, to
be opened and analyzed by other tools, for example spreadsheet programs like MS
Excel, Apple Numbers or Libre Office Calc, by pressing File -> Export Data.

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3.8.4

J-Link software and documentation package

Symbol Configuration

The symbol context menu can be accessed by right-clicking the corresponding row in
the watch below the graph.
From the context menu the Y-resolution, visibility and color of the graph, as well as
the display as hexadecimal or decimal can be configured.
When sampling is stopped, symbols can be removed or added via the context menu.

3.8.5

Short Cuts

The Y-Resolution of a symbol can be changed be selecting the respective row in the
watch and using the "+" and "-" keys.
The visibility of a symbol can be changed by pressing "enter".
Scrolling through the Graph Window can be done with the mouse wheel.
Holding control while using the mouse wheel will zoom in and out the time base.

3.8.6

GUI Meters and Controls

3.8.6.1 Toolbar

I.

Show/Hide the Graph | Show/Hide Watch Window

II. Start sampling | Stop sampling | Pause / Resume sampling
III. Zoom in | Zoom out
IV. Start the target | Halt the target | Reset the target

3.8.6.2

Statusbar

I. Start:
II. X-Resolution:
III. Status:
IV. Sampling:
V. Samples in Buffer:

J-Link / J-Trace (UM08001)

Timestamp of the 1st value currently shown in the graph.
Displayed time per division.
Shows the lastest status message
Indicates whether HSS is currently running or not.
Shows the current amount of datapoints stored in buffer

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3.9

SWO Analyzer
SWO Analyzer (SWOAnalyzer.exe) is a tool that analyzes SWO output. Status and
summary of the analysis are output to standard out, the details of the analysis are
stored in a file.

Usage
SWOAnalyzer.exe 
This can be achieved by simply dragging the SWO output file created by the J-Link
DLL onto the executable.

Creating an SWO output file
In order to create the SWO output file, which is th input file for the SWO Analyzer,
the J-Link config file needs to be modified.
It should contain the following lines:
[SWO]
SWOLogFile="C:\TestSWO.dat"

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3.10 JTAGLoad (Command line tool)
JTAGLoad is a tool that can be used to open and execute an svf (Serial vector format)
file for JTAG boundary scan tests. The data in the file will be sent to the target via JLink / J-Trace.

SVF is a standard format for boundary scan vectors to be used with different tools
and targets. SVF files contain human-readable ASCII SVF statements consisting of an
SVF command, the data to be sent, the expected response, a mask for the response
or additional information.
JTAGLoad supports following SVF commands:
•
•
•
•
•
•
•
•
•
•
•
•
•

ENDDR
ENDIR
FREQUENCY
HDR
HIR
PIOMAP
PIO
RUNTEST
SDR
SIR
STATE
TDR
TIR

A simple SVF file to read the JTAG ID of the target can look like following:
! Set JTAG frequency
FREQUENCY 12000000HZ;
! Configure scan chain
! For a single device in chain, header and trailer data on DR and IR are 0
! Set TAP to IDLE state
STATE IDLE;
! Configure end state of DR and IR after scan operations
ENDDR IDLE;
ENDIR IDLE;
! Start of test
! 32 bit scan on DR, In: 32 0 bits, Expected out: Device ID (0x0BA00477)
SDR 32 TDI (0) TDO (0BA00477) MASK (0FFFFFFF);
! Set TAP to IDLE state
STATE IDLE;
! End of test

SVD files allow even more complex tasks, basically everything which is possible via
JTAG and the devices in the scan chain, like configuring an FPGA or loading data into
memory.

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3.11 J-Link RDI (Remote Debug Interface)
The J-Link RDI software is a remote debug interface for J-Link. It makes it possible to
use J-Link with any RDI compliant debugger. The main part of the software is an RDIcompliant DLL, which needs to be selected in the debugger. There are two additional
features available which build on the RDI software foundation. Each additional feature requires an RDI license in addition to its own license. Evaluation licenses are
available free of charge. For further information go to our website or contact us
directly.
Note:
The RDI software (as well as flash breakpoints and flash downloads) do
not require a license if the target device is an LPC2xxx. In this case the software verifies that the target device is actually an LPC 2xxx and have a device-based license.

3.11.1 Flash download and flash breakpoints
Flash download and flash breakpoints are supported by J-Link RDI. For more information about flash download and flash breakpoints, please refer to J-Link RDI User’s
Guide (UM08004), chapter Flash download and chapter Breakpoints in flash memory.

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3.12 Processor specific tools
The J-Link software and documentation package includes some tools which support
processor specific functionalities, like unlocking a device.

3.12.1 J-Link STR91x Commander (Command line tool)
J-Link STR91x Commander (JLinkSTR91x.exe) is a tool that can be used to configure
STR91x cores. It permits some STR9 specific commands like:
•
•
•
•
•

Set the configuration register to boot from bank 0 or 1.
Erase flash sectors.
Read and write the OTP sector of the flash.
Write-protect single flash sectors by setting the sector protection bits.
Prevent flash from communicate via JTAG by setting the security bit.

All of the actions performed by the commands, excluding writing the OTP sector and
erasing the flash, can be undone. This tool can be used to erase the flash of the controller even if a program is in flash which causes the CPU core to stall.

When starting the STR91x commander, a command sequence will be performed
which brings MCU into Turbo Mode.
"While enabling the Turbo Mode, a dedicated test mode signal is set and controls the
GPIOs in output. The IOs are maintained in this state until a next JTAG instruction is
sent." (ST Microelectronics)
Enabling Turbo Mode is necessary to guarantee proper function of all commands in
the STR91x Commander.

3.12.1.1 Command line options
J-Link STR91x Commander can be started with different command line options. In
the following, the command line options which are available for J-Link STR91x Commander are explained.

-CommandFile
Selects a command file and starts J-Link STR91x Commander in batch mode. The
batch mode of J-Link Commander is similar to the execution of a batch file. The command file is parsed line by line and one command is executed at a time.

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Syntax
-CommanderScript 

Example
See Using command files on page 82

-DRPre, -DRPost, -IRPre and -IRPost (Scan-Chain Configuration )
STR91x allows to configure a specific scan-chain via command-line. To use this feature four command line options have to be specified in order to allow a proper connection to the proper device. In case of passing an incomplete configuration, the
utility tries to auto-detect.

Syntax
-DRPre 
-DRPost 
-IRPre 
-IRPost 

Example
JLink.exe -DRPre 1 -DRPost 4 -IRPre

16

-IRPost 20

-IP
Selects IP as host interface to connect to J-Link. Default host interface is USB.

Syntax
-IP 

Example
JLinkSTR91x.exe -IP 192.168.1.17

Additional information
To select from a list of all available emulators on Ethernet, please use * as .

-SelectEmuBySN
Connect to a J-Link with a specific serial number via USB. Useful if multiple J-Links
are connected to the same PC and multiple instances of J-Link STR91x Commander
shall run and each connects to another J-Link.

Syntax
-SelectEmuBySN 

Example
JLinkSTR91x.exe -SelectEmuBySN 580011111

3.12.2 J-Link STM32 Unlock (Command line tool)
J-Link STM32 Unlock (JLinkSTM32.exe) is a free command line tool which can be
used to disable the hardware watchdog of STM32 devices which can be activated by
programming the option bytes. Moreover the J-Link STM32 Commander unsecures a
read-protected STM32 device by re-programming the option bytes.

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Note:
memory.

J-Link software and documentation package

Unprotecting a secured device or will cause a mass erase of the flash

3.12.2.1 Command Line Options
The J-Link STM32 Unlock Utility can be started with different command line options
for test and automation purposes. In the following, the available command line
options are explained.

-IP
Selects IP as host interface to connect to J-Link. Default host interface is USB.
Syntax
-IP 

Example
JLinkSTM32.exe -IP 192.168.1.17

Additional information
To select from a list of all available emulators on Ethernet, please use * as .

-SelectEmuBySN
Connect to a J-Link with a specific serial number via USB. Useful if multiple J-Links
are connected to the same PC.
Syntax
-SelectEmuBySN 

Example
JLinkSTM32.exe -SelectEmuBySN 580011111

-Speed
Starts J-Link STM32 Unlock Utility with a given initial speed. Available parameters
are "adaptive", "auto" or a freely selectable integer value in kHz. It is recommended to use either a fixed speed or, if it is available on the target, adaptive
speeds. Default interface speed is 1000 kHz.
Syntax
-Speed 

-SetPowerTarget
The connected debug probe will power the target via pin 19 of the debug connector.
Syntax

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-SetPowerTarget 

Example
JLinkSTM32.exe -SetPowerTarget 1

// Target power will be set

-SetDeviceFamily
This command allows to specify a device family, so that no user input is required to
start the unlocking process.
Syntax
-SetDeviceFamily 

Parameter
There are two different options to specify the device family to be used:
a) Pass the list index from the list which shows all supported familys on start up
b) Pass the defined device name
ListIndex
1
2
3
4
5
6

Name
STM32F0xxxx
STM32F1xxxx
STM32F2xxxx
STM32F3xxxx
STM32F4xxxx
STM32L1xxxx

Table 3.14: Available Parameter for -SetDeviceFamily

Example
JLinkSTM32.exe -SetDeviceFamily 6

// Selects STM32L1 series

JLinkSTM32.exe -SetDeviceFamily STM32L1xxxx

// Selects STM32L1 series

-Exit
In general, the J-Link STM32 utility waits at the end of the unlock process for any
user input before application closes. This option allows to skip this step, so that the
utility closes automatically.
Syntax
-Exit 

Example
JLinkSTM32.exe -Exit 1

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// J-Link STM32 utility closes automatically

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3.13 J-Link Software Developer Kit (SDK)
The J-Link Software Developer Kit is needed if you want to write your own program
with J-Link / J-Trace. The J-Link DLL is a standard Windows DLL typically used from C
programs (Visual Basic or Delphi projects are also possible). It makes the entire
functionality of J-Link / J-Trace available through its exported functions, such as halting/stepping the CPU core, reading/writing CPU and ICE registers and reading/writing
memory. Therefore it can be used in any kind of application accessing a CPU core.
The standard DLL does not have API functions for flash programming. However, the
functionality offered can be used to program flash. In this case, a flash loader is
required. The table below lists some of the included files and their respective purpose.
The J-Link SDK requires an additional license and is available upon request from
www.segger.com.

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Chapter 4
Setup

This chapter describes the setup procedure required in order to work with J-Link / JTrace. Primarily this includes the installation of the J-Link software and documentation package, which also includes a kernel mode J-Link USB driver in your host system.

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CHAPTER 4

Setup

4.1 Installing the J-Link software and documentation
pack
J-Link is shipped with a bundle of applications, corresponding manuals and some
example projects and the kernel mode J-Link USB driver. Some of the applications
require an additional license, free trial licenses are available upon request from
www.segger.com.
Refer to chapter J-Link software and documentation package on page 63 for an overview of the J-Link software and documentation pack.

4.1.1

Setup procedure

To install the J-Link software and documentation pack, follow this procedure:
Note:
We recommend to check if a newer version of the J-Link software and documentation pack is available for download before starting the installation. Check
therefore the J-Link related download section of our website:
http://www.segger.com/download_jlink.html
1.

Before you plug your J-Link / J-Trace into your computer's USB port, extract the
setup tool Setup_JLinkARM_V.zip. The setup wizard will
install the software and documentation pack that also includes the certified JLink USB driver. Start the setup by double clicking Setup_JLinkARM_V.exe. The license Agreement dialog box will be opened. Accept the
terms with the Yes button.

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2.

The Welcome dialog box is opened. Click Next > to open the Choose Destination Location dialog box.

3.

Accept
the
default
installation
path
C:\Program
Files\SEGGER\JLinkARM_V or choose an alternative location. Confirm
your choice with the Next > button.

4.

The Choose options dialog is opened.
The Install J-Link Serial Port Driver installs the driver for J-Links with CDC
functionality. It is not preselected since J-Links without CDC functionality do not
need this driver.
The Create entry in start menu creates an entry in start menu. It is preselected.
The Add shortcuts to desktop option can be selected in order to create a
shortcut on the desktop.
Accept or deselect the options and confirm the selection with the Next > button.

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5.

The installation process will start.

6.

The J-Link DLL Updater pops up, which allows you to update the DLL of an
installed IDE to the DLL verion which is included in the installer. For further information about the J-Link DLL updater, please refer to J-Link DLL updater on
page 153.

7.

The Installation Complete dialog box appears after the copy process. Close the
installation wizard with the Finish > button.
The J-Link software and documentation pack is successfully installed on your PC.

8.

Connect your J-Link via USB with your PC. The J-Link will be identified and after
a short period the J-Link LED stops rapidly flashing and stays on permanently.

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4.2

Setting up the USB interface
After installing the J-Link software and documentation package it should not be necessary to perform any additional setup sequences in order to configure the USB interface of J-Link.

4.2.1

Verifying correct driver installation

To verify the correct installation of the driver, disconnect and reconnect J-Link / JTrace to the USB port. During the enumeration process which takes about 2 seconds,
the LED on J-Link / J-Trace is flashing. After successful enumeration, the LED stays
on permanently.
Start the provided sample application JLink.exe, which should display the compilation time of the J-Link firmware, the serial number, a target voltage of 0.000V, a
complementary error message, which says that the supply voltage is too low if no
target is connected to J-Link / J-Trace, and the speed selection. The screenshot below
shows an example.

In addition you can verify the driver installation by consulting the Windows device
manager. If the driver is installed and your J-Link / J-Trace is connected to your computer, the device manager should list the J-Link USB driver as a node below "Universal Serial Bus controllers" as shown in the following screenshot:

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Right-click on the driver to open a context menu which contains the command Properties. If you select this command, a J-Link driver Properties dialog box is opened
and should report: This device is working properly.

If you experience problems, refer to the chapter Support and FAQs on page 379 for
help. You can select the Driver tab for detailed information about driver provider,
version, date and digital signer.

4.2.2

Uninstalling the J-Link USB driver

If J-Link / J-Trace is not properly recognized by Windows and therefore does not enumerate, it makes sense to uninstall the J-Link USB driver.
This might be the case when:
•
•

The LED on the J-Link / J-Trace is rapidly flashing.
The J-Link / J-Trace is recognized as Unknown Device by Windows.

To have a clean system and help Windows to reinstall the J-Link driver, follow this
procedure:
1.
2.

Disconnect J-Link / J-Trace from your PC.
Open the Add/Remove Programs dialog (Start > Settings > Control Panel
> Add/Remove Programs) and select Windows Driver Package - Segger

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(jlink) USB and click the Change/Remove button.

3.

Confirm the uninstallation process.

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4.3

Setup

Setting up the IP interface
Some emulators of the J-Link family have (or future members will have) an additional
Ethernet interface, to communicate with the host system. These emulators will also
come with a built-in web server which allows configuration of the emulator via web
interface. In addition to that, you can set a default gateway for the emulator which
allows using it even in large intranets. For simplicity the setup process of J-Link Pro
(referred to as J-Link) is described in this section.

4.3.1

Configuring J-Link using J-Link Configurator

The J-Link software and documentation package comes with a free GUI-based utility
called J-Link Configurator which auto-detects all J-Links that are connected to the
host PC via USB & Ethernet. The J-Link Configurator allows the user to setup the IP
interface of J-Link. For more information about how to use the J-Link Configurator,
please refer to J-Link Configurator on page 149.

4.3.2

Configuring J-Link using the webinterface

All emulators of the J-Link family which come with an Ethernet interface also come
with a built-in web server, which provides a web interface for configuration. This
enables the user to configure J-Link without additional tools, just with a simple web
browser. The Home page of the web interface shows the serial number, the current
IP address and the MAC address of the J-Link.

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The Network configuration page allows configuration of network related settings
(IP address, subnet mask, default gateway) of J-Link. The user can choose between
automatic IP assignment (settings are provided by a DHCP server in the network)
and manual IP assignment by selecting the appropriate radio button.

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4.4
Q:
A:

CHAPTER 4

Setup

FAQs
How can I use J-Link with GDB and Ethernet?
You have to use the J-Link GDB Server in order to connect to J-Link via GDB and
Ethernet.

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4.5

J-Link Configurator
Normally, no configuration is required, especially when using J-Link via USB. For special cases like having multiple older J-Links connected to the same host PC in parallel, they need to be re-configured to be identified by their real serial number when
enumerating on the host PC. This is the default identification method for current JLinks (J-Link with hardware version 8 or later). For re-configuration of old J-Links or
for configuration of the IP settings (use DHCP, IP address, subnet mask, ...) of a JLink supporting the Ethernet interface, SEGGER provides a GUI-based tool, called JLink Configurator. The J-Link Configurator is part of the J-Link software and documentation package and can be used free of charge.

4.5.1

Configure J-Links using the J-Link Configurator

A J-Link can be easily configured by selecting the appropriate J-Link from the emulator list and using right click -> Configure.

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In order to configure an old J-Link, which uses the old USB 0 - 3 USB identification
method, to use the new USB identification method (reporting the real serial number)
simply select "Real SN" as USB identification method and click the OK button. The
same dialog also allows configuration of the IP settings of the connected J-Link if it
supports the Ethernet interface.

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4.6

J-Link USB identification
In general, when using USB, there are two ways in which a J-Link can be identified:
•
•

By serial number
By USB address

Default configuration of J-Link is: Identification by serial number. Identification via
USB address is used for compatibility and not recommended.

Background information
"USB address" really means changing the USB-Product ID (PID).
The following table shows how J-Links enumerate in the different identification
modes.
Identification
Serial number (default)
USB
USB
USB
USB

address
address
address
address

0
1
2
3

(Deprecated)
(Deprecated)
(Deprecated)
(Deprecated)

PID
0x0101
0x0101
0x0102
0x0103
0x0104

Serial number
Serial number is real serial number of the
J-Link or user assigned.
123456
123456
123456
123456

Table 4.1: J-Link enumeration in different identification modes

4.6.1 Connecting to different J-Links connected to the same
host PC via USB
In general, when having multiple J-Links connected to the same PC, the J-Link to
connect to is explicitly selected by its serial number. Most software/debuggers provide an extra field to type-in the serial number of the J-Link to connect to.
The following screenshot shows the connection dialog of the J-Flash software:

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The following screenshot shows the connection dialog of IAR EWARM:

A debugger / software which does not provide such a functionality, the J-Link DLL
automatically detects that multiple J-Links are connected to the PC and shows a
selection dialog which allows the user to select the appropriate J-Link he wants to
connect to.

So even in IDEs which do not have an selection option for the J-Link, it is possible to
connect to different J-Links.

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4.7

Using the J-Link DLL

4.7.1

What is the JLink DLL?

The J-LinkARM.dll is a standard Windows DLL typically used from C or C++, but
also Visual Basic or Delphi projects. It makes the entire functionality of the J-Link / JTrace available through the exported functions.
The functionality includes things such as halting/stepping the ARM core, reading/
writing CPU and ICE registers and reading/writing memory. Therefore, it can be used
in any kind of application accessing a CPU core.

4.7.2

Updating the DLL in third-party programs

The JLink DLL can be used by any debugger that is designed to work with it. Some
debuggers are usually shipped with the J-Link DLL already installed. Anyhow it may
make sense to replace the included DLL with the latest one available, to take advantage of improvements in the newer version.

4.7.2.1 Updating the J-Link DLL in the IAR Embedded Workbench for
ARM (EWARM)
It is recommended to use the J-Link DLL updater to update the J-Link DLL in the IAR
Embedded Workbench. The IAR Embedded Workbench IDE is a high-performance
integrated development environment with an editor, compiler, linker, debugger. The
compiler generates very efficient code and is widely used. It comes with the JLinkARM.dll in the arm\bin subdirectory of the installation directory. To update this
DLL, you should backup your original DLL and then replace it with the new one.
Typically, the DLL is located in C:\Program Files\IAR Systems\Embedded Workbench 6.n\arm\bin\.
After updating the DLL, it is recommended to verify that the new DLL is loaded as
described in Determining which DLL is used by a program on page 154.

J-Link DLL updater
The J-Link DLL updater is a tool which comes with the J-Link software and allows the
user to update the JLinkARM.dll in all installations of the IAR Embedded Workbench, in a simple way. The updater is automatically started after the installation of a
J-Link software version and asks for updating old DLLs used by IAR. The J-Link DLL
updater can also be started manually. Simply enable the checkbox left to the IAR
installation which has been found. Click Ok in order to update the JLinkARM.dll
used by the IAR installation.

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4.7.3

Setup

Determining the version of JLink DLL

To determine which version of the JLinkARM.dll you are using, the DLL version can be
viewed by right clicking the DLL in explorer and choosing Properties from the context menu. Click the Version tab to display information about the product version.

4.7.4

Determining which DLL is used by a program

To verify that the program you are working with is using the DLL you expect it to use,
you can investigate which DLLs are loaded by your program with tools like Sysinternals’ Process Explorer. It shows you details about the DLLs used by your program,
such as manufacturer and version.

Process Explorer is - at the time of writing - a free utility which can be downloaded
from www.sysinternals.com.

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4.8

Getting started with J-Link and ARM DS-5
J-Link supports ARM DS-5 Development via the RDDI protocol.
For commercially using J-Link via RDDI in ARM DS-5, an RDI/RDDI license is
required. J-Link models which come with an RDI license, can also be used via RDDI.
RDDI can be evaluated free of charge.
In order to use J-Link in ARM DS-5 Development Studio, the RDDI DLL in DS-5 needs
to be replaced by the SEGGER version of this DLL. The SEGGER version of the RDDI
still allows using ARM’s DSTREAM in DS-5. After installing the J-Link software and
documentation package, the J-Link DLL Updater is started which allows easily updating the RDDI DLL in DS-5. An backup of the original DLL is made automatically.

4.8.1

Replacing the RDDI DLL manually

If J-Link DLL Updater is unable to find a DS-5 installation and does not list it for
updating, the RDDI DLL can always be replaced manually. For more information
about
how
to
manually
update
the
RDDI
DLL,
please
refer
to
$JLINK_INST_DIR$\RDDI\ManualInstallation.txt.

4.8.2

Using J-Link in DS-5 Development Studio

Please follow the following steps, in order to use J-Link in DS-5, after replacing the
RDDI DLL accordingly:
•
•
•
•
•
•
•
•
•

•
•

Connect J-Link and target.
Open ARM DS-5.
Open DS-5 Project for target.
Open Debug Configurations...
Select DS-5 Debugger on the left side.
Press New button.
In the Connection tab, select The target from the device database, Bare Metal
Debug, Debug via DSTREAM/RVI.
Click on the Browse... button right to the Text box at the bottom Connection.
In the Dialog select the J-Link which is connected to the target (e.g.
JLinkUSB:174200001).

Click OK.
Add the device name to the connection string (e.g. JLinkUSB:174200001:Device

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STM32F103ZG).

•
•
•
•
•
•

Click Apply.
In the Files tab, select the application to download.
In the Debugger tab, select 'Debug from symbol' and enter main or select Debug
from entry point.
Click Apply.
Start a new debug session with the newly created debug configuration.
Now the debug session should start and downloaded the application to the target.

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Chapter 5
Working with J-Link and J-Trace

This chapter describes functionality and how to use J-Link and J-Trace.

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5.1

Working with J-Link and J-Trace

Connecting the target system

5.1.1

Power-on sequence

In general, J-Link / J-Trace should be powered on before connecting it with the target
device. That means you should first connect J-Link / J-Trace with the host system via
USB and then connect J-Link / J-Trace with the target device via JTAG. Power-on the
device after you connected J-Link / J-Trace to it.

5.1.2

Verifying target device connection

If the USB driver is working properly and your J-Link / J-Trace is connected with the
host system, you may connect J-Link / J-Trace to your target hardware. Then start
JLink.exe which should now display the normal J-Link / J-Trace related information
and in addition to that it should report that it found a JTAG target and the target’s
core ID. The screenshot below shows the output of JLink.exe. As can be seen, it
reports a J-Link with one JTAG device connected.

5.1.3

Problems

If you experience problems with any of the steps described above, read the chapter
Support and FAQs on page 379 for troubleshooting tips. If you still do not find appropriate help there and your J-Link / J-Trace is an original SEGGER product, you can
contact SEGGER support via e-mail. Provide the necessary information about your
target processor, board etc. and we will try to solve your problem. A checklist of the
required information together with the contact information can be found in chapter
Support and FAQs on page 379 as well.

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5.2

Indicators
J-Link uses indicators (LEDs) to give the user some information about the current
status of the connected J-Link. All J-Links feature the main indicator. Some newer JLinks such as the J-Link Pro / Ultra come with additional input/output Indicators. In
the following, the meaning of these indicators will be explained.

5.2.1

Main indicator

For J-Links up to V7, the main indicator is single color (Green). J-Link V8 comes with
a bi-color indicator (Green & Red LED), which can show multiple colors: green, red
and orange.

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5.2.1.1 Single color indicator (J-Link V7 and earlier)
Indicator status

Meaning

GREEN, flashing at 10 Hz Emulator enumerates.

GREEN, flickering

Emulator is in operation. Whenever the emulator is executing a command, the LED is switched off temporarily.
Flickering speed depends on target interface speed. At
low interface speeds, operations typically take longer and
the "OFF" periods are typically longer than at fast
speeds.

GREEN, constant

Emulator has enumerated and is in idle mode.

GREEN, switched off for
10ms once per second

J-Link heart beat. Will be activated after the emulator
has been in idle mode for at least 7 seconds.

GREEN, flashing at 1 Hz

Emulator has a fatal error. This should not normally happen.

Table 5.1: J-Link single color main indicator

5.2.1.2 Bi-color indicator (J-Link V8)
Indicator status

Meaning

GREEN, flashing at 10 Hz Emulator enumerates.

GREEN, flickering

Emulator is in operation. Whenever the emulator is executing a command, the LED is switched off temporarily.
Flickering speed depends on target interface speed. At
low interface speeds, operations typically take longer and
the "OFF" periods are typically longer than at fast
speeds.

GREEN, constant

Emulator has enumerated and is in idle mode.

GREEN, switched off for
10ms once per second

J-Link heart beat. Will be activated after the emulator
has been in idle mode for at least 7 seconds.

ORANGE

Reset is active on target.

RED, flashing at 1 Hz

Emulator has a fatal error. This should not normally happen.

Table 5.2: J-Link single color LED main color indicator

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5.2.2

Input indicator

Some newer J-Links such as the J-Link Pro/Ultra come with additional input/output
indicators. The input indicator is used to give the user some information about the
status of the target hardware.

5.2.2.1 Bi-color input indicator
Indicator status

Meaning

GREEN

Target voltage could be measured. Target is connected.

ORANGE

Target voltage could be measured. RESET is pulled low
(active) on target side.

RED

RESET is pulled low (active) on target side. If no target is
connected, reset will also be active on target side.

Table 5.3: J-Link bi-color input indicator

5.2.3

Output indicator

Some newer J-Links such as the J-Link Pro/Ultra come with additional input/output
indicators. The output indicator is used to give the user some information about the
emulator-to-target connection.

5.2.3.1 Bi-color output indicator
Indicator status

Meaning

OFF

Target power supply via Pin 19 is not active.

GREEN

Target power supply via Pin 19 is active.

ORANGE

Target power supply via Pin 19 is active. Emulator pulls
RESET low (active).

RED

Emulator pulls RESET low (active).

Table 5.4: J-Link bi-color output indicator

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5.3

Working with J-Link and J-Trace

JTAG interface
By default, only one device is assumed to be in the JTAG scan chain. If you have multiple devices in the scan chain, you must properly configure it. To do so, you have to
specify the exact position of the CPU that should be addressed. Configuration of the scan
is done by the target application. A target application can be a debugger such as the
IAR C-SPY® debugger, ARM’s AXD using RDI, a flash programming application such
as SEGGER’s J-Flash, or any other application using J-Link / J-Trace. It is the application’s responsibility to supply a way to configure the scan chain. Most applications
offer a dialog box for this purpose.

5.3.1

Multiple devices in the scan chain

J-Link / J-Trace can handle multiple devices in the scan chain. This applies to hardware where multiple chips are connected to the same JTAG connector. As can be seen
in the following figure, the TCK and TMS lines of all JTAG device are connected, while
the TDI and TDO lines form a bus.

TDO

TRST

TCK
TRST

TMS

TCK
TDI

Device 0

TDI

TMS

TDO

TRST

Device 1

TMS

TCK

TDI

TDO

JTAG

Currently, up to 8 devices in the scan chain are supported. One or more of these
devices can be CPU cores; the other devices can be of any other type but need to
comply with the JTAG standard.

5.3.1.1 Configuration
The configuration of the scan chain depends on the application used. Read JTAG
interface on page 162 for further instructions and configuration examples.

5.3.2

Sample configuration dialog boxes

As explained before, it is the responsibility of the application to allow the user to configure the scan chain. This is typically done in a dialog box; some sample dialog
boxes are shown below.

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SEGGER J-Flash configuration dialog
This dialog box can be found at Options|Project settings.

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SEGGER J-Link RDI configuration dialog box
This dialog can be found under RDI|Configure for example in IAR Embedded Workbench®. For detailed information check the IAR Embedded Workbench user guide.

IAR J-Link configuration dialog box
This dialog box can be found under Project|Options.

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5.3.3

Determining values for scan chain configuration

When do I need to configure the scan chain?
If only one device is connected to the scan chain, the default configuration can be
used. In other cases, J-Link / J-Trace may succeed in automatically recognizing the
devices on the scan chain, but whether this is possible depends on the devices
present on the scan chain.

How do I configure the scan chain?
2 values need to be known:
•
•

The position of the target device in the scan chain.
The total number of bits in the instruction registers of the devices before the target device (IR len).

The position can usually be seen in the schematic; the IR len can be found in the
manual supplied by the manufacturers of the others devices.
ARM7/ARM9 have an IR len of four.

Sample configurations
The diagram below shows a scan chain configuration sample with 2 devices connected to the JTAG port.

TCK
TRST

TMS

TCK
TDI

Device 0

TDO

TRST

TDI

TMS

TDO

TRST

Device 1

TMS

TCK

TDI

TDO

JTAG

Examples
The following table shows a few sample configurations with 1,2 and 3 devices in different configurations.
Device 0
Device 1
Device 2
Chip(IR len) Chip(IR len) Chip(IR len)

Position

IR len

Xilinx(8)
ARM(4)
Xilinx(8)

0
0
1
2

0
0
8
16

ARM(4)
ARM(4)
Xilinx(8)
Xilinx(8)

ARM(4)

Table 5.5: Example scan chain configurations

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Device 0
Device 1
Device 2
Chip(IR len) Chip(IR len) Chip(IR len)

Position

IR len

Xilinx(8)
Xilinx(8)
ARM(4)

0
2
1

0
12
8

ARM(4)
ARM(4)
Xilinx(8)

ARM(4)
ARM(4)
Xilinx(8)

Table 5.5: Example scan chain configurations

The target device is marked in blue.

5.3.4

JTAG Speed

There are basically three types of speed settings:
•
•
•

Fixed JTAG speed.
Automatic JTAG speed.
Adaptive clocking.

These are explained below.

5.3.4.1 Fixed JTAG speed
The target is clocked at a fixed clock speed. The maximum JTAG speed the target can
handle depends on the target itself. In general CPU cores without JTAG synchronization logic (such as ARM7-TDMI) can handle JTAG speeds up to the CPU speed, ARM
cores with JTAG synchronization logic (such as ARM7-TDMI-S, ARM946E-S,
ARM966EJ-S) can handle JTAG speeds up to 1/6 of the CPU speed.
JTAG speeds of more than 10 MHz are not recommended.

5.3.4.2 Automatic JTAG speed
Selects the maximum JTAG speed handled by the TAP controller.
Note:
On ARM cores without synchronization logic, this may not work reliably,
because the CPU core may be clocked slower than the maximum JTAG speed.

5.3.4.3 Adaptive clocking
If the target provides the RTCK signal, select the adaptive clocking function to synchronize the clock to the processor clock outside the core. This ensures there are no
synchronization problems over the JTAG interface.
If you use the adaptive clocking feature, transmission delays, gate delays, and synchronization requirements result in a lower maximum clock frequency than with nonadaptive clocking.

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5.4

SWD interface
The J-Link support ARMs Serial Wire Debug (SWD). SWD replaces the 5-pin JTAG port
with a clock (SWDCLK) and a single bi-directional data pin (SWDIO), providing all the
normal JTAG debug and test functionality. SWDIO and SWCLK are overlaid on the
TMS and TCK pins. In order to communicate with a SWD device, J-Link sends out
data on SWDIO, synchronous to the SWCLK. With every rising edge of SWCLK, one
bit of data is transmitted or received on the SWDIO.

5.4.1

SWD speed

Currently only fixed SWD speed is supported by J-Link. The target is clocked at a
fixed clock speed. The SWD speed which is used for target communication should not
exceed target CPU speed * 10. The maximum SWD speed which is supported by JLink depends on the hardware version and model of J-Link. For more information
about the maximum SWD speed for each J-Link / J-Trace model, please refer to JLink / J-Trace models on page 26.

5.4.2

SWO

Serial Wire Output (SWO) support means support for a single pin output signal from
the core. The Instrumentation Trace Macrocell (ITM) and Serial Wire Output (SWO)
can be used to form a Serial Wire Viewer (SWV). The Serial Wire Viewer provides a
low cost method of obtaining information from inside the MCU.
Usually it should not be necessary to configure the SWO speed because this is usually
done by the debugger.

5.4.2.1 Max. SWO speeds
The supported SWO speeds depend on the connected emulator. They can be retrieved
from the emulator. To get the supported SWO speeds for your emulator, use J-Link
Commander:
J-Link> si 1
//Select target interface SWD
J-Link> SWOSpeed

Currently, following speeds are supported:
Emulator
J-Link V9
J-Link Pro/ULTRA V4

Speed formula
60MHz/n, n >= 8
3.2GHz/n, n >= 64

Resulting max. speed
7.5 MHz
50 MHz

Table 5.6: J-Link supported SWO input speeds

5.4.2.2 Configuring SWO speeds
The max. SWO speed in practice is the max. speed which both, target and J-Link can
handle. J-Link can handle the frequencies described in SWO on page 167 whereas the
max. deviation between the target and the J-Link speed is about 3%.
The computation of possible SWO speeds is typically done in the debugger. The SWO
output speed of the CPU is determined by TRACECLKIN, which is normally the same
as the CPU clock.

Example1
Target CPU running at 72 MHz. n is be between 1 and 8192.
Possible SWO output speeds are:
72MHz, 36MHz, 24MHz, ...
J-Link V9: Supported SWO input speeds are: 60MHz / n, n>= 8:
7.5MHz, 6.66MHz, 6MHz, ...

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Permitted combinations are:
SWO output
6MHz, n = 12
4MHz, n = 18
...
2MHz, n = 36
...

SWO input
6MHz, n = 10
4MHz, n = 15
...
2MHz, n = 30
...

Deviation percent
0
0
<= 3
0
...

Table 5.7: Permitted SWO speed combinations

Example 2
Target CPU running at 10 MHz.
Possible SWO output speeds are:
10MHz, 5MHz, 3.33MHz, ...
J-Link V7: Supported SWO input speeds are: 6MHz / n, n>= 1:
6MHz, 3MHz, 2MHz, 1.5MHz, ...
Permitted combinations are:
SWO output
2MHz, n = 5
1MHz, n = 10
769kHz, n = 13
...

SWO input
2MHz, n = 3
1MHz, n = 6
750kHz, n = 8
...

Deviation percent
0
0
2.53
...

Table 5.8: Permitted SWO speed combinations

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5.5

Multi-core debugging
J-Link / J-Trace is able to debug multiple cores on one target system connected to the
same scan chain. Configuring and using this feature is described in this section.

5.5.1

How multi-core debugging works

Multi-core debugging requires multiple debuggers or multiple instances of the same
debugger. Two or more debuggers can use the same J-Link / J-Trace simultaneously.
Configuring a debugger to work with a core in a multi-core environment does not
require special settings. All that is required is proper setup of the scan chain for each
debugger. This enables J-Link / J-Trace to debug more than one core on a target at
the same time.
The following figure shows a host, debugging two CPU cores with two instances of the
same debugger.

Host (PC)

Debugger

Debugger

Instance 1

Instance 2

USB

J-Link

JTAG

CPU0

Target hardware

CPU1

Both debuggers share the same physical connection. The core to debug is selected
through the JTAG-settings as described below.

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5.5.2

Working with J-Link and J-Trace

Using multi-core debugging in detail

1.
2.
3.

Connect your target to J-Link / J-Trace.
Start your debugger, for example IAR Embedded Workbench for ARM.
Choose Project|Options and configure your scan chain. The picture below
shows the configuration for the first CPU core on your target.

4.
5.

Start debugging the first core.
Start another debugger, for example another instance of IAR Embedded Workbench for ARM.

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6.

Choose Project|Options and configure your second scan chain. The following
dialog box shows the configuration for the second ARM core on your target.

7.

Start debugging your second core.

Example:
Core #1

Core #2

Core #3

TAP number TAP number
debugger #1 debugger #2

ARM7TDMI ARM7TDMI-S ARM7TDMI 0
ARM7TDMI ARM7TDMI ARM7TDMI
0
ARM7TDM
ARM7TDMI-S ARM7TDMI-S 1
I-S

1
2
2

Table 5.9: Multicore debugging

Cores to debug are marked in blue.

5.5.3

Things you should be aware of

Multi-core debugging is more difficult than single-core debugging. You should be
aware of the pitfalls related to JTAG speed and resetting the target.

5.5.3.1 JTAG speed
Each core has its own maximum JTAG speed. The maximum JTAG speed of all cores
in the same chain is the minimum of the maximum JTAG speeds.
For example:
•
•
•

Core #1:
2MHz maximum JTAG speed
Core #2:
4MHz maximum JTAG speed
Scan chain: 2MHz maximum JTAG speed

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5.5.3.2 Resetting the target
All cores share the same RESET line. You should be aware that resetting one core
through the RESET line means resetting all cores which have their RESET pins connected to the RESET line on the target.

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5.6

Connecting multiple J-Links / J-Traces to your PC
In general, it is possible to have an unlimited number of J-Links / J-Traces connected
to the same PC. Current J-Link models are already factory-configured to be used in a
multi-J-Link environment, older J-Links can be re-configured to use them in a multiJ-link environment.

5.6.1

How does it work?

USB devices are identified by the OS by their product ID, vendor id and serial number. The serial number reported by current J-Links is a unique number which allows
to have an almost unlimited number of J-Links connected to the same host at the
same time. In order to connect to the correct J-Link, the user has to make sure that
the correct J-Link is selected (by SN or IP). In cases where no specific J-Link is
selected, following pop-up will shop and allow the user to select the proper J-Link:

The sketch below shows a host, running two application programs. Each applicationcommunicates with one CPU core via a separate J-Link.

Host (PC)

Application

Application

Instance 1

Instance 2

USB

USB

J-Link
1

J-Link
2

JTAG

JTAG

CPU0

CPU1

Target hardware 1

Target hardware 2

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Older J-Links may report USB0-3 instead of unique serial number when enumerating
via USB. For these J-Links, we recommend to re-configure them to use the new enumeration method (report real serial number) since the USB0-3 behavior is obsolete.
Re-configuration can be done by using the J-Link Configurator, which is part of the JLink software and documentation package. For further information about the J-Link
configurator and how to use it, please refer to J-Link Configurator on page 149.

Re-configuration to the old USB 0-3 enumeration method
In some special cases, it may be necessary to switch back to the obsolete USB 0-3
enumeration method. For example, old IAR EWARM versions supports connecting to a
J-Link via the USB0-3 method only. As soon as more than one J-Link is connected to
the pc, there is no oppertunity to pre-select the J-Link which should be used for a
debug session.
Below, a small instruction of how to re-configure J-Link to enumerate with the old
obsolete enumeration method in order to prevent compatibility problems, a short
instruction is give on how to set USB enumeration method to USB 2 is given:
Config area byte

Meaning

0

USB-Address. Can be set to 0-3, 0xFF is default which
means USB-Address 0.

1

Enumeration method
0x00 / 0xFF: USB-Address is used for enumeration.
0x01:
Real-SN is used for enumeration.

Table 5.10: Config area layout: USB-Enumeration settings

Example for setting enumeration method to USB 2:
1.
2.
3.
4.

Start J-Link Commander (JLink.exe) which is part of the J-Link software
Enter wconf 0 02
// Set USB-Address 2
Enter wconf 1 00
// Set enumeration method to USB-Address
Power-cycle J-Link in order to apply new configuration.

Re-configuration to REAL-SN enumeration can be done by using the J-Link Configurator, which is part of the J-Link software and documentation package. For further
information about the J-Link configurator and how to use it, please refer to J-Link
Configurator on page 149.

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5.7

J-Link control panel
Since software version V3.86 J-Link the J-Link control panel window allows the user
to monitor the J-Link status and the target status information in real-time. It also
allows the user to configure the use of some J-Link features such as flash download,
flash breakpoints and instruction set simulation. The J-Link control panel window can
be accessed via the J-Link tray icon in the tray icon list. This icon is available when
the debug session is started.

To open the status window, simply click on the tray icon.

5.7.1

Tabs

The J-Link status window supports different features which are grouped in tabs. The
organization of each tab and the functionality which is behind these groups will be
explained in this section

5.7.1.1 General
In the General section, general information about J-Link and the target hardware
are shown. Moreover the following general settings can be configured:
•
•
•

Show tray icon: If this checkbox is disabled the tray icon will not show from the
next time the DLL is loaded.
Start minimized: If this checkbox is disabled the J-Link status window will show
up automatically each time the DLL is loaded.
Always on top: if this checkbox is enabled the J-Link status window is always
visible even if other windows will be opened.

The general information about target hardware and J-Link which are shown in this
section, are:
•
•
•
•
•
•
•

Process: Shows the path of the file which loaded the DLL.
J-Link: Shows OEM of the connected J-Link, the hardware version and the Serial
number. If no J-Link is connected it shows "not connected" and the color indicator is red.
Target interface: Shows the selected target interface (JTAG/SWD) and the current JTAG speed. The target current is also shown. (Only visible if J-Link is connected)
Endian: Shows the target endianess (Only visible if J-Link is connected)
Device: Shows the selected device for the current debug session.
License: Opens the J-Link license manager.
About: Opens the about dialog.

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5.7.1.2 Settings
In the Settings section project- and debug-specific settings can be set. It allows the
configuration of the use of flash download and flash breakpoints and some other target specific settings which will be explained in this topic. Settings are saved in the
configuration file. This configuration file needs to be set by the debugger. If the
debugger does not set it, settings can not be saved. All settings can only the changed
by the user himself. All settings which are modified during the debug session have to
be saved by pressing Save settings, otherwise they are lost when the debug session
is closed.

Section: Flash download
In this section, settings for the use of the J-Link FlashDL feature and related settings can be configured. When a license for J-Link FlashDL is found, the color indicator is green and "License found" appears right to the J-Link FlashDL usage
settings.

•
•
•
•

•

Auto: This is the default setting of J-Link FlashDL usage. If a license is found
J-Link FlashDL is enabled. Otherwise J-Link FlashDL will be disabled internally.
On: Enables the J-Link FlashDL feature. If no license has been found an error
message appears.
Off: Disables the J-Link FlashDL feature.
Skip download on CRC match: J-Link checks the CRC of the flash content to
determine if the current application has already been downloaded to the flash. If
a CRC match occurs, the flash download is not necessary and skipped. (Only
available if J-Link FlashDL usage is configured as Auto or On)
Verify download: If this checkbox is enabled J-Link verifies the flash content
after the download. (Only available if J-Link FlashDL usage is configured as
Auto or On)

Section: Flash breakpoints:
In this section, settings for the use of the FlashBP feature and related settings can
be configured. When a license for FlashBP is found, the color indicator is green and
"License found" appears right to the FlashBP usage settings.

•
•
•
•

Auto: This is the default setting of FlashBP usage. If a license has been found
the FlashBP feature will be enabled. Otherwise FlashBP will be disabled internally.
On: Enables the FlashBP feature. If no license has been found an error message
appears.
Off: Disables the FlashBP feature.
Show window during program: When this checkbox is enabled the "Programming flash" window is shown when flash is re-programmed in order to set/clear
flash breakpoints.

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Flash download and flash breakpoints independent settings
These settings do not belong to the J-Link flash download and flash breakpoints settings section. They can be configured without any license needed.

•

•
•

•
•
•

•

Log file: Shows the path where the J-Link log file is placed. It is possible to
override the selection manually by enabling the Override checkbox. If the Override checkbox is enabled a button appears which let the user choose the new
location of the log file.
Settings file: Shows the path where the configuration file is placed. This configuration file contains all the settings which can be configured in the Settings tab.
Override device selection: If this checkbox is enabled, a dropdown list
appears, which allows the user to set a device manually. This especially makes
sense when J-Link can not identify the device name given by the debugger or if a
particular device is not yet known to the debugger, but to the J-Link software.
Allow caching of flash contents: If this checkbox is enabled, the flash contents are cached by J-Link to avoid reading data twice. This speeds up the transfer between debugger and target.
Allow instruction set simulation: If this checkbox is enabled, instructions will
be simulated as far as possible. This speeds up single stepping, especially when
FlashBPs are used.
Save settings: When this button is pushed, the current settings in the Settings
tab will be saved in a configuration file. This file is created by J-Link and will be
created for each project and each project configuration (e.g. Debug_RAM,
Debug_Flash). If no settings file is given, this button is not visible.
Modify breakpoints during execution: This dropdown box allows the user to
change the behavior of the DLL when setting breakpoints if the CPU is running.
The following options are available:
Allow: Allows settings breakpoints while the CPU is running. If the CPU needs to
be halted in order to set the breakpoint, the DLL halts the CPU, sets the breakpoints and restarts the CPU.
Allow if CPU does not need to be halted: Allows setting breakpoints while the
CPU is running, if it does not need to be halted in order to set the breakpoint. If
the CPU has to be halted the breakpoint is not set.
Ask user if CPU needs to be halted: If the user tries to set a breakpoint while
the CPU is running and the CPU needs to be halted in order to set the breakpoint,
the user is asked if the breakpoint should be set. If the breakpoint can be set
without halting the CPU, the breakpoint is set without explicit confirmation by the
user.
Do not allow: It is not allowed to set breakpoints while the CPU is running.

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5.7.1.3 Break/Watch
In the Break/Watch section all breakpoints and watchpoints which are in the DLL
internal breakpoint and watchpoint list are shown.

Section: Code
Lists all breakpoints which are in the DLL internal breakpoint list are shown.
•
•
•
•
•

Handle: Shows the handle of the breakpoint.
Address: Shows the address where the breakpoint is set.
Mode: Describes the breakpoint type (ARM/THUMB)
Permission: Describes the breakpoint implementation flags.
Implementation: Describes the breakpoint implementation type. The breakpoint types are: RAM, Flash, Hard. An additional TBC (to be cleared) or TBS (to
be set) gives information about if the breakpoint is (still) written to the target or
if it’s just in the breakpoint list to be written/cleared.

Note:
It is possible for the debugger to bypass the breakpoint functionality of
the J-Link software by writing to the debug registers directly. This means for ARM7/
ARM9 cores write accesses to the ICE registers, for Cortex-M3 devices write accesses
to the memory mapped flash breakpoint registers and in general simple write
accesses for software breakpoints (if the program is located in RAM). In these cases,
the J-Link software cannot determine the breakpoints set and the list is empty.

Section: Data
In this section, all data breakpoints which are listed in the DLL internal breakpoint
list are shown.
•
•
•
•
•
•
•
•

Handle: Shows the handle of the data breakpoint.
Address: Shows the address where the data breakpoint is set.
AddrMask: Specifies which bits of Address are disregarded during the comparison for a data breakpoint match. (A 1 in the mask means: disregard this bit)
Data: Shows on which data to be monitored at the address where the data
breakpoint is set.
Data Mask: Specifies which bits of Data are disregarded during the comparison
for a data breakpoint match. (A 1 in the mask means: disregard this bit)
Ctrl: Specifies the access type of the data breakpoint (read/write).
CtrlMask: Specifies which bits of Ctrl are disregarded during the comparison for
a data breakpoint match.

5.7.1.4 Log
In this section the log output of the DLL is shown. The user can determine which
function calls should be shown in the log window.

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Available function calls to log: Register read/write, Memory read/write, set/clear
breakpoint, step, go, halt, is halted.

5.7.1.5 CPU Regs
In this section the name and the value of the CPU registers are shown.

5.7.1.6 Target Power
In this section currently just the power consumption of the target hardware is shown.

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5.7.1.7 SWV
In this section SWV information are shown.

•
•
•
•
•
•

Status: Shows the encoding and the baudrate of the SWV data received by the
target (Manchester/UART, currently J-Link only supports UART encoding).
Bytes in buffer: Shows how many bytes are in the DLL SWV data buffer.
Bytes transferred: Shows how many bytes have been transferred via SWV,
since the debug session has been started.
Refresh counter: Shows how often the SWV information in this section has
been updated since the debug session has been started.
Host buffer: Shows the reserved buffer size for SWV data, on the host side.
Emulator buffer: Shows the reserved buffer size for SWV data, on the emulator
side.

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5.8

Reset strategies
J-Link / J-Trace supports different reset strategies. This is necessary because there is
no single way of resetting and halting a CPU core before it starts to execute instructions. For example reset strategies which use the reset pin can not succeed on targets where the reset pin of the CPU is not connected to the reset pin of the JTAG
connector. Reset strategy 0 is always the recommended one because it has been
adapted to work on every target even if the reset pin (Pin 15) is not connected.

What is the problem if the core executes some instructions after RESET?
The instructions which are executed can cause various problems. Some cores can be
completely "confused", which means they can not be switched into debug mode (CPU
can not be halted). In other cases, the CPU may already have initialized some hardware components, causing unexpected interrupts or worse, the hardware may have
been initialized with illegal values. In some of these cases, such as illegal PLL settings, the CPU may be operated beyond specification, possibly locking the CPU.

5.8.1

Strategies for ARM 7/9 devices

5.8.1.1 Type 0: Hardware, halt after reset (normal)
The hardware reset pin is used to reset the CPU. After reset release, J-Link continuously tries to halt the CPU. This typically halts the CPU shortly after reset release;
the CPU can in most systems execute some instructions before it is halted. The number of instructions executed depends primarily on the JTAG speed: the higher the
JTAG speed, the faster the CPU can be halted.
Some CPUs can actually be halted before executing any instruction, because the start
of the CPU is delayed after reset release. If a pause has been specified, J-Link waits
for the specified time before trying to halt the CPU. This can be useful if a bootloader
which resides in flash or ROM needs to be started after reset.
This reset strategy is typically used if nRESET and nTRST are coupled. If nRESET and
nTRST are coupled, either on the board or the CPU itself, reset clears the breakpoint,
which means that the CPU can not be stopped after reset with the BP@0 reset strategy.

5.8.1.2 Type 1: Hardware, halt with BP@0
The hardware reset pin is used to reset the CPU. Before doing so, the ICE breaker is
programmed to halt program execution at address 0; effectively, a breakpoint is set
at address 0. If this strategy works, the CPU is actually halted before executing a single instruction.
This reset strategy does not work on all systems for two reasons:
•
•

If nRESET and nTRST are coupled, either on the board or the CPU itself, reset
clears the breakpoint, which means the CPU is not stopped after reset.
Some MCUs contain a bootloader program (sometimes called kernel), which
needs to be executed to enable JTAG access.

5.8.1.3 Type 2: Software, for Analog Devices ADuC7xxx MCUs
This reset strategy is a software strategy. The CPU is halted and performs a sequence
which causes a peripheral reset. The following sequence is executed:
•
•
•
•

The CPU is halted.
A software reset sequence is downloaded to RAM.
A breakpoint at address 0 is set.
The software reset sequence is executed.

This sequence performs a reset of CPU and peripherals and halts the CPU before executing instructions of the user program. It is the recommended reset sequence for
Analog Devices ADuC7xxx MCUs and works with these chips only.
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5.8.1.4 Type 3: No reset
No reset is performed. Nothing happens.

5.8.1.5 Type 4: Hardware, halt with WP
The hardware RESET pin is used to reset the CPU. After reset release, J-Link continuously tries to halt the CPU using a watchpoint. This typically halts the CPU shortly
after reset release; the CPU can in most systems execute some instructions before it
is halted.
The number of instructions executed depends primarily on the JTAG speed: the
higher the JTAG speed, the faster the CPU can be halted. Some CPUs can actually be
halted before executing any instruction, because the start of the CPU is delayed after
reset release

5.8.1.6 Type 5: Hardware, halt with DBGRQ
The hardware RESET pin is used to reset the CPU. After reset release, J-Link continuously tries to halt the CPU using the DBGRQ. This typically halts the CPU shortly after
reset release; the CPU can in most systems execute some instructions before it is
halted.
The number of instructions executed depends primarily on the JTAG speed: the
higher the JTAG speed, the faster the CPU can be halted. Some CPUs can actually be
halted before executing any instruction, because the start of the CPU is delayed after
reset release.

5.8.1.7 Type 6: Software
This reset strategy is only a software reset. "Software reset" means basically no
reset, just changing the CPU registers such as PC and CPSR. This reset strategy sets
the CPU registers to their after-Reset values:
•
•
•
•
•

PC = 0
CPSR = 0xD3 (Supervisor mode, ARM, IRQ / FIQ disabled)
All SPSR registers = 0x10
All other registers (which are unpredictable after reset) are set to 0.
The hardware RESET pin is not affected.

5.8.1.8 Type 7: Reserved
Reserved reset type.

5.8.1.9 Type 8: Software, for ATMEL AT91SAM7 MCUs
The reset pin of the device is disabled by default. This means that the reset strategies which rely on the reset pin (low pulse on reset) do not work by default. For this
reason a special reset strategy has been made available.
It is recommended to use this reset strategy. This special reset strategy resets the
peripherals by writing to the RSTC_CR register. Resetting the peripherals puts all
peripherals in the defined reset state. This includes memory mapping register, which
means that after reset flash is mapped to address 0. It is also possible to achieve the
same effect by writing 0x4 to the RSTC_CR register located at address 0xfffffd00.

5.8.1.10 Type 9: Hardware, for NXP LPC MCUs
After reset a bootloader is mapped at address 0 on ARM 7 LPC devices. This reset
strategy performs a reset via reset strategy Type 1 in order to reset the CPU. It also
ensures that flash is mapped to address 0 by writing the MEMMAP register of the LPC.
This reset strategy is the recommended one for all ARM 7 LPC devices.

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5.8.2

Strategies for Cortex-M devices

J-Link supports different specific reset strategies for the Cortex-M cores. All of the
following reset strategies are available in JTAG and in SWD mode. All of them halt the
CPU after the reset.
Note:
It is recommended that the correct device is selected in the debugger so
the debugger can pass the device name to the J-Link DLL which makes it possible for
J-Link to detect what is the best reset strategy for the device. Moreover, we recommend that the debugger uses reset type 0 to allow J-Link to dynamically select what
reset is the best for the connected device.

5.8.2.1 Type 0: Normal
This is the default strategy. It does whatever is the best way to reset the target
device.
If the correct device is selected in the debugger this reset strategy may also perform
some special handling which might be necessary for the connected device. This for
example is the case for devices which have a ROM bootloader that needs to run after
reset and before the user application is started (especially if the debug interface is
disabled after reset and needs to be enabled by the ROM bootloader).
For most devices, this reset strategy does the same as reset strategy 8 does:
1.
2.
3.
4.

Make sure that the device halts immediately after reset (before it can execute any
instruction of the user application) by setting the VC_CORERESET in the DEMCR.
Reset the core and peripherals by setting the SYSRESETREQ bit in the AIRCR.
Wait for the S_RESET_ST bit in the DHCSR to first become high (reset active) and
then low (reset no longer active) afterwards.
Clear VC_CORERESET.

5.8.2.2 Type 1: Core
Only the core is reset via the VECTRESET bit. The peripherals are not affected. After
setting the VECTRESET bit, J-Link waits for the S_RESET_ST bit in the Debug Halting
Control and Status Register (DHCSR) to first become high and then low afterwards.
The CPU does not start execution of the program because J-Link sets the
VC_CORERESET bit before reset, which causes the CPU to halt before execution of the
first instruction.
Note:
In most cases it is not recommended to reset the core only since most target applications rely of the reset state of some peripherals (PLL, External memory
interface etc.) and may be confused if they boot up but the peripherals are already
configured.

5.8.2.3 Type 2: ResetPin
J-Link pulls its RESET pin low to reset the core and the peripherals. This normally
causes the CPU RESET pin of the target device to go low as well, resulting in a reset
of both CPU and peripherals. This reset strategy will fail if the RESET pin of the target
device is not pulled low. The CPU does not start execution of the program because JLink sets the VC_CORERESET bit before reset, which causes the CPU to halt before
execution of the first instruction.

5.8.2.4 Type 3: Connect under Reset
J-Link connects to the target while keeping Reset active (reset is pulled low and
remains low while connecting to the target). This is the recommended reset strategy
for STM32 devices. This reset strategy has been designed for the case that communication with the core is not possible in normal mode so the VC_CORERESET bit can not
be set in order to guarantee that the core is halted immediately after reset.

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5.8.2.5 Type 4: Reset core & peripherals, halt after bootloader
Same as type 0, but bootloader is always executed. This reset strategy has been
designed for MCUs/CPUs which have a bootloader located in ROM which needs to run
at first, after reset (since it might initialize some target settings to their reset state).
When using this reset strategy, J-Link will let the bootloader run after reset and halts
the target immediately after the bootloader and before the target application is
started. This is the recommended reset strategy for LPC11xx and LPC13xx devices
where a bootloader should execute after reset to put the chip into the "real" reset
state.

5.8.2.6 Type 5: Reset core & peripherals, halt before bootloader
Basically the same as reset type 8. Performs a reset of core & peripherals and halts
the CPU immediately after reset. The ROM bootloader is NOT executed.

5.8.2.7 Type 6: Reset for Freescale Kinetis devices
Performs a via reset strategy 0 (normal) first in order to reset the core & peripherals
and halt the CPU immediately after reset. After the CPU is halted, the watchdog is
disabled, since the watchdog is running after reset by default. If the target application does not feed the watchdog, J-Link loses connection to the device since it is
reset permanently.

5.8.2.8 Type 7: Reset for Analog Devices CPUs (ADI Halt after kernel)
Performs a reset of the core and peripherals by setting the SYSRESETREQ bit in the
AIRCR. The core is allowed to perform the ADI kernel (which enables the debug interface) but the core is halted before the first instruction after the kernel is executed in
order to guarantee that no user application code is performed after reset.

5.8.2.9 Type 8: Reset core and peripherals
J-Link tries to reset both, core and peripherals by setting the SYSRESETREQ bit in the
AIRCR. VC_CORERESET in the DEMCR is also set to make sure that the CPU is halted
immediately after reset and before executing any instruction.
Reset procedure:
1.
2.
3.
4.

Make sure that the device halts immediately after reset (before it can execute any
instruction of the user application) by setting the VC_CORERESET in the DEMCR.
Reset the core and peripherals by setting the SYSRESETREQ bit in the AIRCR.
Wait for the S_RESET_ST bit in the DHCSR to first become high (reset active) and
then low (reset no longer active) afterwards.
Clear VC_CORERESET.

This type of reset may fail if:
•
•

J-Link has no connection to the debug interface of the CPU because it is in a low
power mode.
The debug interface is disabled after reset and needs to be enabled by a device
internal bootloader. This would cause J-Link to lose communication after reset
since the CPU is halted before it can execute the internal bootlader.

5.8.2.10 Type 9: Reset for LPC1200 devices
On the NXP LPC1200 devices the watchdog is enabled after reset and not disabled by
the bootloader, if a valid application is in the flash memory. Moreover, the watchdog
keeps counting if the CPU is in debug mode. When using this reset strategy, J-Link
performs a reset of the CPU and peripherals, using the SYSRESETREQ bit in the AIRCR
and halts the CPU after the bootloader has been performed and before the first

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instruction of the user code is executed. Then the watchdog of the LPC1200 device is
disabled. This reset strategy is only guaranteed to work on "modern" J-Links (J-Link
V8, J-Link Pro, J-link ULTRA, J-Trace for Cortex-M, J-Link Lite) and if a SWD speed of
min. 1 MHz is used. This reset strategy should also work for J-Links with hardware
version 6, but it can not be guaranteed that these J-Links are always fast enough in
disabling the watchdog.

5.8.2.11 Type 10: Reset for Samsung S3FN60D devices
On the Samsung S3FN60D devices the watchdog may be running after reset (if the
watchdog is active after reset or not depends on content of the smart option bytes at
addr 0xC0). The watchdog keeps counting even if the CPU is in debug mode (e.g.
halted by a halt request or halted by vector catch). When using this reset strategy, JLink performs a reset of the CPU and peripherals, using the SYSRESETREQ bit and sets
VC_CORERESET in order to halt the CPU after reset, before it executes a single instruction. Then the watchdog of the S3FN60D device is disabled.

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5.9

Working with J-Link and J-Trace

Using DCC for memory access
The ARM7/9 architecture requires cooperation of the CPU to access memory when the
CPU is running (not in debug mode). This means that memory cannot normally be
accessed while the CPU is executing the application program. The normal way to read
or write memory is to halt the CPU (put it into debug mode) before accessing memory. Even if the CPU is restarted after the memory access, the real time behavior is
significantly affected; halting and restarting the CPU costs typically multiple milliseconds. For this reason, most debuggers do not even allow memory access if the CPU is
running.
However, there is one other option: DCC (Direct communication channel) can be used
to communicate with the CPU while it is executing the application program. All that is
required is the application program to call a DCC handler from time to time. This DCC
handler typically requires less than 1 µs per call.
The DCC handler, as well as the optional DCC abort handler, is part of the J-Link software package and can be found in the Samples\DCC\IAR directory of the package.

5.9.1
•
•
•

What is required?
An application program on the host (typically a debugger) that uses DCC.
A target application program that regularly calls the DCC handler.
The supplied abort handler should be installed (optional).

An application program that uses DCC is JLink.exe.

5.9.2

Target DCC handler

The target DCC handler is a simple C-file taking care of the communication. The function DCC_Process() needs to be called regularly from the application program or
from an interrupt handler. If an RTOS is used, a good place to call the DCC handler is
from the timer tick interrupt. In general, the more often the DCC handler is called,
the faster memory can be accessed. On most devices, it is also possible to let the
DCC generate an interrupt which can be used to call the DCC handler.

5.9.3

Target DCC abort handler

An optional DCC abort handler (a simple assembly file) can be included in the application. The DCC abort handler allows data aborts caused by memory reads/writes via
DCC to be handled gracefully. If the data abort has been caused by the DCC communication, it returns to the instruction right after the one causing the abort, allowing
the application program to continue to run. In addition to that, it allows the host to
detect if a data abort occurred.
In order to use the DCC abort handler, 3 things need to be done:
•
•
•

Place a branch to DCC_Abort at address 0x10 ("vector" used for data aborts).
Initialize the Abort-mode stack pointer to an area of at least 8 bytes of stack
memory required by the handler.
Add the DCC abort handler assembly file to the application.

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5.10 J-Link script files
In some situations it it necessary to customize some actions performed by J-Link. In
most cases it is the connection sequence and/or the way in which a reset is performed by J-Link, since some custom hardware needs some special handling which
cannot be integrated into the generic part of the J-Link software. J-Link script files
are written in C-like syntax in order to have an easy start to learning how to write JLink script files. The script file syntax supports most statements (if-else, while, declaration of variables, ...) which are allowed in C, but not all of them. Moreover, there
are some statements that are script file specific. The script file allows maximum flexibility, so almost any target initialization which is necessary can be supported.

5.10.1 Actions that can be customized
The script file support allows customizing of different actions performed by J-Link.
Depending on whether the corresponding function is present in the script file or not,
a generically implemented action is replaced by an action defined in a script file. In
the following all J-Link actions which can be customized using a script file are listed
and explained.

5.10.1.1 ResetTarget()
Description
If present, it replaces the reset strategy performed by the DLL when issuing a reset.

Prototype
void ResetTarget(void);

5.10.1.2 InitEMU()
Description
If present, it allows configuration of the emulator prior to starting target communication. Currently this function is only used to configure whether the target which is
connected to J-Link has an ETB or not. For more information on how to configure the
existence of an ETB, please refer to Global DLL variables on page 193.

Prototype
void InitEMU(void);

5.10.1.3 InitTarget()
Description
If present, it can replace the auto-detection capability of J-Link. Some targets can
not be auto-detected by J-Link since some special target initialization is necessary
before communication with the core is possible. Moreover, J-Link uses a TAP reset to
get the JTAG IDs of the devices in the JTAG chain. On some targets this disables
access to the core.

Prototype
void InitTarget(void);

5.10.2 Script file API functions
In the following, the API functions which can be used in a script file to communicate
with the DLL are explained.

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5.10.2.1 MessageBox()
Description
Outputs a string in a message box.

Prototype
__api__ int MessageBox(const char * sMsg);

5.10.2.2 MessageBox1()
Description
Outputs a constant character string in a message box. In addition to that, a given
value (can be a constant value, the return value of a function or a variable) is added,
right behind the string.

Prototype
__api__ int MessageBox1(const char * sMsg, int v);

5.10.2.3 Report()
Description
Outputs a constant character string on stdio.

Prototype
__api__ int Report(const char * sMsg);

5.10.2.4 Report1()
Description
Outputs a constant character string on stdio. In addition to that, a given value (can
be a constant value, the return value of a function or a variable) is added, right
behind the string.

Prototype
__api__ int Report1(const char * sMsg, int v);

5.10.2.5 JTAG_SetDeviceId()
Description
Sets the JTAG ID of a specified device, in the JTAG chain. The index of the device
depends on its position in the JTAG chain. The device closest to TDO has index 0. The
Id is used by the DLL to recognize the device.
Before calling this function, please make sure that the JTAG chain has been configured correctly by setting the appropriate global DLL variables. For more information
about the known global DLL variables, please refer to Global DLL variables on
page 193.

Prototype
__api__ int JTAG_SetDeviceId(int DeviceIndex, unsigned int Id);

5.10.2.6 JTAG_GetDeviceId()
Description
Retrieves the JTAG ID of a specified device, in the JTAG chain. The index of the
device depends on its position in the JTAG chain. The device closest to TDO has index
0.

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Prototype
__api__ int JTAG_GetDeviceId(int DeviceIndex);

5.10.2.7 JTAG_WriteIR()
Description
Writes a JTAG instruction.
Before calling this function, please make sure that the JTAG chain has been configured correctly by setting the appropriate global DLL variables. For more information
about the known global DLL variables, please refer to Global DLL variables on
page 193.

Prototype
__api__ int JTAG_WriteIR(unsigned int Cmd);

5.10.2.8 JTAG_StoreIR()
Description
Stores a JTAG instruction in the DLL JTAG buffer.
Before calling this function, please make sure that the JTAG chain has been configured correctly by setting the appropriate global DLL variables. For more information
about the known global DLL variables, please refer to Global DLL variables on
page 193.

Prototype
__api__ int JTAG_StoreIR(unsigned int Cmd);

5.10.2.9 JTAG_WriteDR()
Description
Writes JTAG data.
Before calling this function, please make sure that the JTAG chain has been configured correctly by setting the appropriate global DLL variables. For more information
about the known global DLL variables, please refer to Global DLL variables on
page 193.

Prototype
__api__ int JTAG_WriteDR(unsigned __int64 tdi, int NumBits);

5.10.2.10JTAG_StoreDR()
Description
Stores JTAG data in the DLL JTAG buffer.
Before calling this function, please make sure that the JTAG chain has been configured correctly by setting the appropriate global DLL variables. For more information
about the known global DLL variables, please refer to Global DLL variables on
page 193.

Prototype
__api__ int JTAG_StoreDR(unsigned __int64 tdi, int NumBits);

5.10.2.11JTAG_Write()
Description
Writes a JTAG sequence (max. 64 bits per pin).

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Prototype
__api__ int JTAG_Write(unsigned __int64 tms, unsigned __int64 tdi, int
NumBits);

5.10.2.12JTAG_Store()
Description
Stores a JTAG sequence (max. 64 bits per pin) in the DLL JTAG buffer.

Prototype
__api__ int JTAG_Store(unsigned __int64 tms, unsigned __int64 tdi, int
NumBits);

5.10.2.13JTAG_GetU32()
Description
Gets 32 bits JTAG data, starting at given bit position.

Prototype
__api__ int JTAG_GetU32(int BitPos);

5.10.2.14JTAG_WriteClocks()
Description
Writes a given number of clocks.

Prototype
__api__ int JTAG_WriteClocks(int NumClocks);

5.10.2.15JTAG_StoreClocks()
Description
Stores a given number of clocks in the DLL JTAG buffer.

Prototype
__api__ int JTAG_StoreClocks(int NumClocks);

5.10.2.16JTAG_Reset()
Description
Performs a TAP reset and tries to auto-detect the JTAG chain (Total IRLen, Number of
devices). If auto-detection was successful, the global DLL variables which determine
the JTAG chain configuration, are set to the correct values. For more information
about the known global DLL variables, please refer to Global DLL variables on
page 193.
Note:
This will not work for devices which need some special init (for example to
add the core to the JTAG chain), which is lost at a TAP reset.

Prototype
__api__ int JTAG_Reset(void);

5.10.2.17SYS_Sleep()
Description
Waits for a given number of miliseconds. During this time, J-Link does not communicate with the target.

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Prototype
__api__ int SYS_Sleep(int Delayms);

5.10.2.18 JLINK_CORESIGHT_AddAP()
Description
Allows the user to manually configure the AP-layout of the device J-Link is connected
to. This makes sense on targets on which J-Link can not perform a auto-detection of
the APs which are present on the target system. Type can only be a known global JLink DLL AP constant. For a list of all available constants, please refer to Global DLL
constants on page 196.

Prototype
__api__ int JLINK_CORESIGHT_AddAP(int Index, unsigned int Type);

Example
JLINK_CORESIGHT_AddAP(0, CORESIGHT_AHB_AP); // First AP is a AHB-AP
JLINK_CORESIGHT_AddAP(1, CORESIGHT_APB_AP); // Second AP is a APB-AP
JLINK_CORESIGHT_AddAP(2, CORESIGHT_JTAG_AP); // Third AP is a JTAG-AP

5.10.2.19JLINK_CORESIGHT_Configure()
Description
Has to be called once, before using any other _CORESIGHT_ function that accesses
the DAP.
Takes a configuration string to prepare target and J-Link for CoreSight function
usage. Configuration string may contain multiple setup parameters that are set.
Setup parameters are separated by a semicolon.
At the end of the JLINK_CORESIGHT_Configure(), the appropriate target interface
switching sequence for the currently active target interface is output, if not disabled
via setup parameter.
This function has to be called again, each time the JTAG chain changes (for dynamically changing JTAG chains like those which include a TI ICEPick), in order to setup
the JTAG chain again.

For JTAG
The SWD -> JTAG switching sequence is output. This also triggers a TAP reset on the
target (TAP controller goes through -> Reset -> Idle state)
The IRPre, DRPre, IRPost, DRPost parameters describe which device inside the JTAG
chain is currently selected for communication.

For SWD
The JTAG -> SWD switching sequence is output.
It is also made sure that the "overrun mode enable" bit in the SW-DP CTRL/STAT register is cleared, as in SWD mode J-Link always assumes that overrun detection mode
is disabled.
Make sure that this bit is NOT set by accident when writing the SW-DP CTRL/STAT
register via the _CORESIGHT_ functions.

Prototype
int JLINK_CORESIGHT_Configure(const char* sConfig);

Example
if (MAIN_ActiveTIF == JLINK_TIF_JTAG) {
// Simple setup where we have TDI -> Cortex-M (4-bits IRLen) -> TDO
JLINK_CORESIGHT_Configure("IRPre=0;DRPre=0;IRPost=0;DRPost=0;IRLenDevice=4");
} else {
// For SWD, no special setup is needed, just output the switching sequence
JLINK_CORESIGHT_Configure("");

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}
v = JLINK_CORESIGHT_ReadDP(JLINK_CORESIGHT_DP_REG_CTRL_STAT);
Report1("DAP-CtrlStat: " v);
// Complex setup where we have TDI -> ICEPick (6-bits IRLen) -> Cortex-M (4-bits
IRLen) -> TDO
JLINK_CORESIGHT_Configure("IRPre=0;DRPre=0;IRPost=6;DRPost=1;IRLenDevice=4;");
v = JLINK_CORESIGHT_ReadDP(JLINK_CORESIGHT_DP_REG_CTRL_STAT);
Report1("DAP-CtrlStat: " v)

Known setup parameters
Parameter

Type

IRPre

DecValue

DRPre

DecValue

IRPost

DecValue

DRPost

DecValue

IRLenDevice

DecValue

PerformTIFInit DecValue

Explanation
Sum of IRLen of all JTAG devices in the JTAG chain,
closer to TDO than the actual one J-Link shall communicate with.
Number of JTAG devices in the JTAG chain, closer to
TDO than the actual one, J-Link shall communicate
with.
Sum of IRLen of all JTAG devices in the JTAG chain, following the actual one, J-Link shall communicate with.
Number of JTAG devices in the JTAG chain, following
the actual one, J-Link shall communicate with.
IRLen of the actual device, J-Link shall communicate
with.
0: Do not output switching sequence etc. once
JLINK_CORESIGHT_Configure() completes.

5.10.2.20JLINK_CORESIGHT_ReadAP()
Description
Reads a specific AP register.
For JTAG, makes sure that AP is selected automatically.
Makes sure that actual data is returned, meaning for register read-accesses which
usually only return data on the second access, this function performs this automatically, so the user will always see valid data.

Prototype
int JLINK_CORESIGHT_ReadAP(unsigned int RegIndex);

Example
v = JLINK_CORESIGHT_ReadAP(JLINK_CORESIGHT_AP_REG_DATA);
Report1("DATA: " v);

5.10.2.21JLINK_CORESIGHT_ReadDP()
Description
Reads a specific DP register.
For JTAG, makes sure that DP is selected automatically.
Makes sure that actual data is returned, meaning for register read-accesses which
usually only return data on the second access, this function performs this automatically, so the user will always see valid data.

Prototype
int JLINK_CORESIGHT_ReadDP(unsigned int RegIndex);

Example
v = JLINK_CORESIGHT_ReadDP(JLINK_CORESIGHT_DP_REG_IDCODE);
Report1("DAP-IDCODE: " v);

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5.10.2.22JLINK_CORESIGHT_WriteAP()
Description
Writes a specific AP register.
For JTAG, makes sure that AP is selected automatically.

Prototype
int JLINK_CORESIGHT_WriteAP(unsigned int RegIndex, unsigned int Data);

Example
JLINK_CORESIGHT_WriteDP(JLINK_CORESIGHT_AP_REG_BD1, 0x1E);

5.10.2.23JLINK_CORESIGHT_WriteDP()
Description
Writes a specific DP register.
For JTAG, makes sure that DP is selected automatically.

Prototype
int JLINK_CORESIGHT_WriteDP(unsigned int RegIndex, unsigned int Data);

Example
JLINK_CORESIGHT_WriteAP(JLINK_CORESIGHT_DP_REG_ABORT, 0x1E);

5.10.3 Global DLL variables
The script file feature also provides some global variables which are used for DLL
configuration. Some of these variables can only be set to some specific values, others
can be set to the whole datatype with. In the following all global variables and their
value ranges are listed and described.
Note:
tialized.

All global variables are treated as unsigned 32-bit values and are zero-ini-

Variable

CPU

Description

R/W

Pre-selects target CPU J-Link is communicating
with. Used in InitTarget() to skip the core autodetection of J-Link. This variable can only be set
to a known global J-Link DLL constant. For a list
W
of all valid values, please refer to Global DLL constants on page 196.
Example
CPU = ARM926EJS;

JTAG_IRPre

Used for JTAG chain configuration. Sets the number of IR-bits of all devices which are closer to
TDO than the one we want to communicate with. R/W
Example
JTAG_IRPre = 6;

JTAG_DRPre

Used for JTAG chain configuration. Sets the number of devices which are closer to TDO than the
R
one we want to communicate with.
Example
JTAG_DRPre = 2;

JTAG_IRPost

Used for JTAG chain configuration. Sets the number of IR-bits of all devices which are closer to
TDI than the one we want to communicate with. R
Example
JTAG_IRPost = 6;

Table 5.11: Global DLL variables

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Variable

JTAG_DRPost

Working with J-Link and J-Trace

Description

R/W

Used for JTAG chain configuration. Sets the number of devices which are closer to TDI than the
R
one we want to "communicate with.
Example
JTAG_DRPost = 0;

JTAG_IRLen

IR-Len (in bits) of the device we want to communicate with.
R
Example
JTAG_IRLen = 4;

JTAG_TotalIRLen

Computed automatically, based on the values of
JTAG_IRPre, JTAG_DRPre, JTAG_IRPost and
JTAG_DRPost.
Example

R

v = JTAG_TotalIRLen;

JTAG_AllowTAPReset

JTAG_Speed

En-/Disables auto-JTAG-detection of J-Link. Has
to be disabled for devices which need some special init (for example to add the core to the JTAG
W
chain), which is lost at a TAP reset.
Allowed values
0 Auto-detection is enabled.
1 Auto-detection is disabled.
Sets the JTAG interface speed. Speed is given in
kHz.
W
Example
JTAG_Speed = 2000; // 2MHz JTAG speed

JTAG_ResetPin

Pulls reset pin low / Releases nRST pin. Used to
issue a reset of the CPU. Value assigned to reset
pin reflects the state. 0 = Low, 1 = high.
Example

W

JTAG_ResetPin = 0;
SYS_Sleep(5); // Give pin some time to get low
JTAG_ResetPin = 1;

JTAG_TRSTPin

Pulls reset pin low / Releases nTRST pin. Used to
issue a reset of the debug logic of the CPU. Value
assigned to reset pin reflects the state. 0 = Low,
1 = high.
W
Example
JTAG_TRSTPin = 0;
SYS_Sleep(5); // Give pin some time to get low
JTAG_TRSTPin = 1;

JTAG_TCKPin

Pulls TCK pin LOW / HIGH. Value assigned to
reset pin reflects the state. 0 = LOW, 1 = HIGH.
Example

R/W

JTAG_TCKPin = 0;

JTAG_TDIPin

Pulls TDI pin LOW / HIGH. Value assigned to
reset pin reflects the state. 0 = LOW, 1 = HIGH.
Example

R/W

JTAG_TDIPin = 0;

JTAG_TMSPin

Pulls TMS pin LOW / HIGH. Value assigned to
reset pin reflects the state. 0 = LOW, 1 = HIGH.
Example

R/W

JTAG_TMSPin = 0;
Table 5.11: Global DLL variables

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Variable

EMU_ETB_IsPresent

Description

R/W

If the connected device has an ETB and you want
to use it with J-link, this variable should be set to
1. Setting this variable in another function as
InitEmu() does not have any effect.
W
Example
void InitEmu(void) {
EMU_ETB_IsPresent = 1;
}

EMU_ETB_UseETB

Uses ETB instead of RAWTRACE capability of the
emulator. Setting this variable in another function as InitEmu() does not have any effect.
Example

R

EMU_ETB_UseETB = 0;

EMU_ETM_IsPresent

Selects whether an ETM is present on the target
or not. Setting this variable in another function
as InitEmu() does not have any effect.
Example

R/W

EMU_ETM_IsPresent= 0;

EMU_ETM_UseETM

Uses ETM as trace source. Setting this variable in
another function as InitEmu() does not have any
W
effect.
Example
EMU_ETM_UseETM = 1;

Disables use of hardware units for JTAG transmissions since this can cause problems on some
EMU_JTAG_
hardware designs.
DisableHWTransmissions
Example

W

EMU_JTAG_DisableHWTransmissions = 1;

Sets base address of core debug component for
CoreSight compliant devices. Setting this variable disables the J-Link auto-detection of the
core debug component base address. Used on
CORESIGHT_CoreBaseAddr devices where auto-detection of the core debug
component base address is not possible due to
incorrect CoreSight information.
Example

R/W

CORESIGHT_CoreBaseAddr = 0x80030000;

CORESIGHT_
IndexAHBAPToUse

Pre-selects an AP as an AHB-AP that J-Link uses
for debug communication (Cortex-M). Setting
this variable is necessary for example when
debugging multi-core devices where multiple
AHB-APs are present (one for each device). This
function can only be used if a AP-layout has been
configured via JLINK_CORESIGHT_AddAP().
Example
W
JLINK_CORESIGHT_AddAP(0, CORESIGHT_AHB_AP);
JLINK_CORESIGHT_AddAP(1, CORESIGHT_AHB_AP);
JLINK_CORESIGHT_AddAP(2, CORESIGHT_APB_AP);
//
// Use second AP as AHB-AP
// for target communication
//
CORESIGHT_IndexAHBAPToUse = 1;

Table 5.11: Global DLL variables

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Variable

CORESIGHT_
IndexAPBAPToUse

MAIN_ResetType

Working with J-Link and J-Trace

Description
Pre-selects an AP as an APB-AP that J-Link uses
for debug communication (Cortex-A/R). Setting
this variable is necessary for example when
debugging multi-core devices where multiple
APB-APs are present (one for each device). This
function can only be used if an AP-layout has
been configured via JLINK_CORESIGHT_AddAP().
Example

R/W

W

JLINK_CORESIGHT_AddAP(0, CORESIGHT_AHB_AP);
JLINK_CORESIGHT_AddAP(1, CORESIGHT_APB_AP);
JLINK_CORESIGHT_AddAP(2, CORESIGHT_APB_AP);
//
// Use third AP as APB-AP
// for target communication
//
CORESIGHT_IndexAPBAPToUse = 2;

Used to determine what reset type is currently
selected by the debugger. This is useful, if the
script has to behave differently in case a specific
reset type is selected by the debugger and the
script file has a ResetTarget() function which
overrides the J-Link reset strategies.
Example

R

if (MAIN_ResetType == 2) {
[...]
} else {
[...]
}

Used to check if this is the first time we are running into InitTarget(). Useful if some init steps
only need to be executed once per debug session.Example
MAIN_IsFirstIdentify

if (MAIN_IsFirstIdentify == 1) {
[...]
} else {
[...]
}

R

Table 5.11: Global DLL variables

5.10.4 Global DLL constants
Currently there are only global DLL constants to set the global DLL variable CPU. If
necessary, more constants will be implemented in the future.

5.10.4.1 Constants for global variable: CPU
The following constants can be used to set the global DLL variable CPU:
•
•
•
•
•
•
•
•
•
•
•
•
•

ARM7
ARM7TDMI
ARM7TDMIR3
ARM7TDMIR4
ARM7TDMIS
ARM7TDMISR3
ARM7TDMISR4
ARM9
ARM9TDMIS
ARM920T
ARM922T
ARM926EJS
ARM946EJS

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•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•

ARM966ES
ARM968ES
ARM11
ARM1136
ARM1136J
ARM1136JS
ARM1136JF
ARM1136JFS
ARM1156
ARM1176
ARM1176J
ARM1176JS
ARM1176IF
ARM1176JFS
CORTEX_M0
CORTEX_M1
CORTEX_M3
CORTEX_M3R1P0
CORTEX_M3R1P1
CORTEX_M3R2P0
CORTEX_M4
CORTEX_M7
CORTEX_A5
CORTEX_A7
CORTEX_A8
CORTEX_A9
CORTEX_A12
CORTEX_A15
CORTEX_A17
CORTEX_R4
CORTEX_R5

5.10.4.2 Constants for "JLINK_CORESIGHT_xxx" functions
APs
•
•
•
•

CORESIGHT_AHB_AP
CORESIGHT_APB_AP
CORESIGHT_JTAG_AP
CORESIGHT_CUSTOM_AP

DP/AP register indexes
•
•
•
•
•
•
•
•
•
•
•
•
•
•

JLINK_CORESIGHT_DP_REG_IDCODE
JLINK_CORESIGHT_DP_REG_ABORT
JLINK_CORESIGHT_DP_REG_CTRL_STAT
JLINK_CORESIGHT_DP_REG_SELECT
JLINK_CORESIGHT_DP_REG_RDBUF
JLINK_CORESIGHT_AP_REG_CTRL
JLINK_CORESIGHT_AP_REG_ADDR
JLINK_CORESIGHT_AP_REG_DATA
JLINK_CORESIGHT_AP_REG_BD0
JLINK_CORESIGHT_AP_REG_BD1
JLINK_CORESIGHT_AP_REG_BD2
JLINK_CORESIGHT_AP_REG_BD3
JLINK_CORESIGHT_AP_REG_ROM
JLINK_CORESIGHT_AP_REG_IDR

5.10.4.3 Constants for global variable "MAIN_ActiveTIF"
•
•

JLINK_TIF_JTAG
JLINK_TIF_SWD

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5.10.5 Script file language
The syntax of the J-Link script file language follows the conventions of the C-language, but it does not support all expresisons and operators which are supported by
the C-language. In the following, the supported operators and expressions are listed.

5.10.5.1 Supported Operators
The following operators are supported by the J-Link script file language:
•
•
•
•
•
•
•
•

Multiplicative operators: *, /, %
Additive operators: +, Bitwise shift operators: <<, >>)
Relational operators: <, >, <=, >=
Equality operators: ==, !=
Bitwise operators: &, |, ^
Logical operators: &&, ||
Assignment operators: =, *=, /=, +=, -=, <<=, >>=, &=, ^=, |=

5.10.5.2 Supported type specifiers
The following type specifiers are supported by the J-Link script file language:
•
•
•
•

void
char
int (32-bit)
__int64

5.10.5.3 Supported type qualifiers
The following type qualifiers are supported by the J-Link script file language:
•
•
•

const
signed
unsigned

5.10.5.4 Supported declarators
The following type qualifiers are supported by the J-Link script file language:
•

Array declarators

5.10.5.5 Supported selection statements
The following selection statements are supported by the J-Link script file language:
•
•

if-statements
if-else-statements

5.10.5.6 Supported iteration statements
The following iteration statements are supported by the J-Link script file language:
•
•

while
do-while

5.10.5.7 Jump statements
The following jump statements are supported by the J-Link script file language:
•

return

5.10.5.8 Sample script files
The J-Link software and documentation package comes with sample script files for
different devices. The sample script files can be found at $JLINK_INST_DIR$\Samples\JLink\Scripts.
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5.10.6 Script file writing example
In the following, a short example of how a J-Link script file could look like. In this
example we assume a JTAG chain with two devices on it (Cortex-A8 4 bits IRLen, custom device 5-bits IRLen).
void InitTarget(void) {
Report("J-Link script example.");
JTAG_Reset();
// Perform TAP reset and J-Link JTAG auto-detection
if (JTAG_TotalIRLen != 9) {
// Basic check if JTAG chain information matches
MessageBox("Can not find xxx device");
return 1;
}
JTAG_DRPre
= 0; // Cortex-A8 is closest to TDO, no no pre devices
JTAG_DRPost
= 1; // 1 device (custom device) comes after the Cortex-A8
JTAG_IRPre
= 0; // Cortex-A8 is closest to TDO, no no pre IR bits
JTAG_IRPost
= 5; // custom device after Cortex-A8 has 5 bits IR len
JTAG_IRLen
= 4; // We selected the Cortex-A8, it has 4 bits IRLen
CPU
= CORTEX_A8; // We are connected to a Cortex-A8
JTAG_AllowTAPReset
= 1;
// We are allowed to enter JTAG TAP reset
//
// We have a non-CoreSight compliant Cortex-A8 here
// which does not allow auto-detection of the Core debug components base address.
// so set it manually to overwrite the DLL auto-detection
//
CORESIGHT_CoreBaseAddr = 0x80030000;
}

5.10.7 Executing J-Link script files
5.10.7.1 In J-Link commander
When J-Link commander is started it searches for a script file called
Default.JLinkScript in the folder wich contains the JLink.exe and the J-Link DLL
(by default the installation folder e.g. "C:\Program Files\SEGGER\JLinkARM_V456\").
If this file is found, it is executed instead of the standard auto detection of J-Link. If
this file is not present, J-Link commander behaves as before and the normal autodetection is performed.

5.10.7.2 In debugger IDE environment
To execute a script file out of your debugger IDE, simply select the script file to execute in the Settings tab of the J-Link control panel and click the save button (after
the debug session has been started). Usually a project file for J-Link is set by the
debugger, which allows the J-Link DLL to save the settings of the control panel in this
project file. After selecting the script file restart your debug session. From now on,
the script file will be executed when starting the debug session.

5.10.7.3 In GDB Server
In order to execute a script file when using J-Link GDB Server, simply start the GDB
Server, using the following command line paramter:
-scriptfile 

For more information about the -scriptfile command line parameter, please refer
to J-Link GDB Server on page 83.

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5.11 Command strings
The behavior of the J-Link can be customized via command strings passed to the
JLinkARM.dll which controls J-Link. Applications such as the J-Link Commander, but
also the C-SPY debugger which is part of the IAR Embedded Workbench, allow passing one or more command strings. Command line strings can be used for passing
commands to J-Link (such as switching on target power supply), as well as customize
the behavior (by defining memory regions and other things) of J-Link. The use of
command strings enables options which can not be set with the configuration dialog
box provided by C-SPY.

5.11.1 List of available commands
The table below lists and describes the available command strings.
Command
device
DisableFlashBPs
EnableFlashBPs
map exclude
map indirectread
map ram
map reset
SetAllowSimulation
SetCheckModeAfterRead
SetResetPulseLen
SetResetType
SetRestartOnClose
SetDbgPowerDownOnClose
SetSysPowerDownOnIdle
SupplyPower
SupplyPowerDefault

Description
Selects the target device.
Disables the FlashPB feature.
Enables the FlashPB feature.
Ignores all memory accesses to specified area.
Specifies an area which should be read indirect.
Specifies location of target RAM.
Restores the default mapping, which means all memory accesses are permitted.
Enables/Disables instruction set simulation.
Enables/Disables CPSR check after read operations.
Defines the length of the RESET pulse in milliseconds.
Selects the reset strategy.
Specifies restart behavior on close.
Used to power-down the debug unit of the target CPU
when the debug session is closed.
Used to power-down the target CPU, when there are
no transmissions between J-Link and target CPU, for a
specified timeframe.
Activates/Deactivates power supply over pin 19 of the
JTAG connector.
Activates/Deactivates power supply over pin 19 of the
JTAG connector permanently.

Table 5.12: Available command line options

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5.11.1.1 device
This command selects the target device.

Syntax
device = 
DeviceID has to be a valid device identifier. For a list of all available device identifiers please refer to chapter Supported devices on page 214.

Example
device = AT91SAM7S256

5.11.1.2 DisableFlashBPs
This command disables the FlashBP feature.

Syntax
DisableFlashBPs

5.11.1.3 EnableFlashBPs
This command enables the FlashBP feature.

Syntax
EnableFlashBPs

5.11.1.4 map exclude
This command excludes a specified memory region from all memory accesses. All
subsequent memory accesses to this memory region are ignored.

Memory mapping
Some devices do not allow access of the entire 4GB memory area. Ideally, the entire
memory can be accessed; if a memory access fails, the CPU reports this by switching
to abort mode. The CPU memory interface allows halting the CPU via a WAIT signal.
On some devices, the WAIT signal stays active when accessing certain unused memory areas. This halts the CPU indefinitely (until RESET) and will therefore end the
debug session. This is exactly what happens when accessing critical memory areas.
Critical memory areas should not be present in a device; they are typically a hardware design problem. Nevertheless, critical memory areas exist on some devices.
To avoid stalling the debug session, a critical memory area can be excluded from
access: J-Link will not try to read or write to critical memory areas and instead
ignore the access silently. Some debuggers (such as IAR C-SPY) can try to access
memory in such areas by dereferencing non-initialized pointers even if the debugged
program (the debuggee) is working perfectly. In situations like this, defining critical
memory areas is a good solution.

Syntax
map exclude -

Example
This is an example for the map
LPC2148 MCU.

exclude command in combination with an NXP

Memory map
0x00000000-0x0007FFFF
0x00080000-0x3FFFFFFF
0x40000000-0x40007FFF

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On-chip flash memory
Reserved
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0x40008000-0x7FCFFFFF
0x7FD00000-0x7FD01FFF
0x7FD02000-0x7FD02000
0x7FFFD000-0x7FFFFFFF
0x80000000-0xDFFFFFFF
0xE0000000-0xEFFFFFFF
0xF0000000-0xFFFFFFFF

Working with J-Link and J-Trace

Reserved
On-chip USB DMA RAM
Reserved
Boot block (remapped from on-chip flash memory)
Reserved
VPB peripherals
AHB peripherals

The "problematic" memory areas are:
0x00080000-0x3FFFFFFF
0x40008000-0x7FCFFFFF
0x7FD02000-0x7FD02000
0x80000000-0xDFFFFFFF

Reserved
Reserved
Reserved
Reserved

To exclude these areas from being accessed through J-Link the map exclude command should be used as follows:
map
map
map
map

exclude
exclude
exclude
exclude

0x00080000-0x3FFFFFFF
0x40008000-0x7FCFFFFF
0x7FD02000-0x7FD02000
0x80000000-0xDFFFFFFF

5.11.1.5 map indirectread
This command can be used to read a memory area indirectly. Indirect reading means
that a small code snippet is downloaded into RAM of the target device, which reads
and transfers the data of the specified memory area to the host. Before map indirectread can be called a RAM area for the indirect read code snippet has to be
defined. Use therefor the map ram command and define a RAM area with a size of >=
256 byte.

Typical applications
Refer to chapter Fast GPIO bug on page 328 for an example.

Syntax
map indirectread -

Example
map indirectread 0x3fffc000-0x3fffcfff

5.11.1.6 map ram
This command should be used to define an area in RAM of the target device. The area
must be 256-byte aligned. The data which was located in the defined area will not be
corrupted. Data which resides in the defined RAM area is saved and will be restored if
necessary. This command has to be executed before map indirectread will be
called.

Typical applications
Refer to chapter Fast GPIO bug on page 328 for an example.

Syntax
map ram -

Example
map ram 0x40000000-0x40003fff;

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5.11.1.7 map reset
This command restores the default memory mapping, which means all memory
accesses are permitted.

Typical applications
Used with other "map" commands to return to the default values. The map reset
command should be called before any other "map" command is called.

Syntax
map reset

Example
map reset

5.11.1.8 SetAllowSimulation
This command can be used to enable or disable the instruction set simulation. By
default the instruction set simulation is enabled.

Syntax
SetAllowSimulation = 0 | 1

Example
SetAllowSimulation 1

// Enables instruction set simulation

5.11.1.9 SetCheckModeAfterRead
This command is used to enable or disable the verification of the CPSR (current processor status register) after each read operation. By default this check is enabled.
However this can cause problems with some CPUs (e.g. if invalid CPSR values are
returned). Please note that if this check is turned off (SetCheckModeAfterRead = 0),
the success of read operations cannot be verified anymore and possible data aborts
are not recognized.

Typical applications
This verification of the CPSR can cause problems with some CPUs (e.g. if invalid CPSR
values are returned). Note that if this check is turned off (SetCheckModeAfterRead =
0), the success of read operations cannot be verified anymore and possible data
aborts are not recognized.

Syntax
SetCheckModeAfterRead = 0 | 1

Example
SetCheckModeAfterRead = 0

5.11.1.10 SetResetPulseLen
This command defines the length of the RESET pulse in milliseconds. The default for
the RESET pulse length is 20 milliseconds.

Syntax
SetResetPulseLen = 

Example
SetResetPulseLen = 50

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5.11.1.11 SetResetType
This command selects the reset startegy which shall be used by J-Link, to reset the
device. The value which is used for this command is analog to the reset type which
shall be selected. For a list of all reset types which are available, please refer to
Reset strategies on page 181. Please note that there different reset strategies for
ARM 7/9 and Cortex-M devices.

Syntax
SetResetType = 

Example
SetResetType = 0

// Selects reset strategy type 0: normal

5.11.1.12 SetRestartOnClose
This command specifies whether the J-Link restarts target execution on close. The
default is to restart target execution. This can be disabled by using this command.

Syntax
SetRestartOnClose = 0 | 1

Example
SetRestartOnClose = 1

5.11.1.13 SetDbgPowerDownOnClose
When using this command, the debug unit of the target CPU is powered-down when
the debug session is closed.
Note:

This command works only for Cortex-M3 devices

Typical applications
This feature is useful to reduce the power consumption of the CPU when no debug
session is active.

Syntax
SetDbgPowerDownOnClose = 

Example
SetDbgPowerDownOnClose = 1 // Enables debug power-down on close.
SetDbgPowerDownOnClose = 0 // Disables debug power-down on close.

5.11.1.14 SetSysPowerDownOnIdle
When using this command, the target CPU is powered-down when no transmission
between J-Link and the target CPU was performed for a specific time. When the next
command is given, the CPU is powered-up.
Note:

This command works only for Cortex-M3 devices.

Typical applications
This feature is useful to reduce the power consumption of the CPU.

Syntax
SetSysPowerDownOnIdle = 
Note:

A 0 for  disables the power-down on idle functionality.

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Example
SetSysPowerDownOnIdle = 10; // The target CPU is powered-down when there is no
// transmission between J-Link and target CPU for at least
10ms

5.11.1.15 SupplyPower
This command activates power supply over pin 19 of the JTAG connector. The KS
(Kickstart) versions of J-Link have the V5 supply over pin 19 activated by default.

Typical applications
This feature is useful for some eval boards that can be powered over the JTAG connector.

Syntax
SupplyPower = 0 | 1

Example
SupplyPower = 1

5.11.1.16 SupplyPowerDefault
This command activates power supply over pin 19 of the JTAG connector permanently. The KS (Kickstart) versions of J-Link have the V5 supply over pin 19 activated
by default.

Typical applications
This feature is useful for some eval boards that can be powered over the JTAG connector.

Syntax
SupplyPowerDefault = 0 | 1

Example
SupplyPowerDefault = 1

5.11.2 Using command strings
5.11.2.1 J-Link Commander
The J-Link command strings can be tested with the J-Link Commander. Use the command exec supplemented by one of the command strings.

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Example
exec SupplyPower = 1
exec map reset
exec map exclude 0x10000000-0x3FFFFFFF

5.11.2.2 IAR Embedded Workbench
The J-Link command strings can be supplied using the C-SPY debugger of the IAR
Embedded Workbench. Open the Project options dialog box and select Debugger.

On the Extra Options page, select Use command line options.
Enter --jlink_exec_command "" in the textfield, as shown in
the screenshot below. If more than one command should be used separate the commands with semicolon.

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5.12 Switching off CPU clock during debug
We recommend not to switch off CPU clock during debug. However, if you do, you
should consider the following:

Non-synthesizable cores (ARM7TDMI, ARM9TDMI, ARM920, etc.)
With these cores, the TAP controller uses the clock signal provided by the emulator,
which means the TAP controller and ICE-Breaker continue to be accessible even if the
CPU has no clock.
Therefore, switching off CPU clock during debug is normally possible if the CPU clock
is periodically (typically using a regular timer interrupt) switched on every few ms for
at least a few us. In this case, the CPU will stop at the first instruction in the ISR
(typically at address 0x18).

Synthesizable cores (ARM7TDMI-S, ARM9E-S, etc.)
With these cores, the clock input of the TAP controller is connected to the output of a
three-stage synchronizer, which is fed by clock signal provided by the emulator,
which means that the TAP controller and ICE-Breaker are not accessible if the CPU
has no clock.
If the RTCK signal is provided, adaptive clocking function can be used to synchronize
the JTAG clock (provided by the emulator) to the processor clock. This way, the JTAG
clock is stopped if the CPU clock is switched off.
If adaptive clocking is used, switching off CPU clock during debug is normally possible if the CPU clock is periodically (typically using a regular timer interrupt) switched
on every few ms for at least a few us. In this case, the CPU will stop at the first
instruction in the ISR (typically at address 0x18).

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5.13 Cache handling
Most target systems with external memory have at least one cache. Typically, ARM7
systems with external memory come with a unified cache, which is used for both
code and data. Most ARM9 systems with external memory come with separate caches
for the instruction bus (I-Cache) and data bus (D-Cache) due to the hardware architecture.

5.13.1 Cache coherency
When debugging or otherwise working with a system with processor with cache, it is
important to maintain the cache(s) and main memory coherent. This is easy in systems with a unified cache and becomes increasingly difficult in systems with hardware architecture. A write buffer and a D-Cache configured in write-back mode can
further complicate the problem.
ARM9 chips have no hardware to keep the caches coherent, so that this is the
responsibility of the software.

5.13.2 Cache clean area
J-Link / J-Trace handles cache cleaning directly through JTAG commands. Unlike
other emulators, it does not have to download code to the target system. This makes
setting up J-Link / J-Trace easier. Therefore, a cache clean area is not required.

5.13.3 Cache handling of ARM7 cores
Because ARM7 cores have a unified cache, there is no need to handle the caches during debug.

5.13.4 Cache handling of ARM9 cores
ARM9 cores with cache require J-Link / J-Trace to handle the caches during debug. If
the processor enters debug state with caches enabled, J-Link / J-Trace does the following:

When entering debug state
J-Link / J-Trace performs the following:
•
•

It stores the current write behavior for the D-Cache.
It selects write-through behavior for the D-Cache.

When leaving debug state
J-Link / J-Trace performs the following:
•
•

It restores the stored write behavior for the D-Cache.
It invalidates the D-Cache.

Note:
The implementation of the cache handling is different for different cores.
However, the cache is handled correctly for all supported ARM9 cores.

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5.14 Virtual COM Port (VCOM)
5.14.1 Configuring Virtual COM Port
In general, the VCOM feature can be disabled and enabled for debug probes which
comes with support for it via J-Link Commander and J-Link Configurator. Below, a
small description of how to use use them to configure the feature is given.
Note:
VCOM can only be used when debugging via SWD target interface. Pin 5 =
J-Link-Tx (out), Pin 17 = J-Link-Rx (in).
Note:
Currently, only J-Link models with hardware version 9 or newer comes
with VCOM capabilites.

5.14.1.1 Via J-Link Configurator
The J-Link software and documentation package comes with a free GUI-based utility
called J-Link Configurator which auto-detects all J-Links that are connected to the
host PC via USB & Ethernet. The J-Link Configurator allows the user to enable and
disable the VCOM. For more information about the J-Link Configurator, please refer to
J-Link Configurator on page 149.

5.14.1.2 Via J-Link Commander
Simply start J-Link Commander, which is part of the J-Link software and documentation package and enter the vcom enable|disable command as in the screenshot
below. After changing the configuration a power on cycle of the debug probe is necessary in order to use the new configuration. For feature information about how to
use the J-Link Commander, please refer to J-Link Commander (Command line tool)
on page 65.

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Chapter 6
Flash download

This chapter describes how the flash download feature of the DLL can be used in different debugger environments.

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6.1

CHAPTER 6

Flash download

Introduction
The J-Link DLL comes with a lot of flash loaders that allow direct programming of
internal flash memory for popular microcontrollers. Moreover, the J-Link DLL also
allows programming of CFI-compliant external NOR flash memory. The flash download feature of the J-Link DLL does not require an extra license and can be used free
of charge.

Why should I use the J-Link flash download feature?
Being able to download code directly into flash from the debugger or integrated IDE
significantly shortens the turn-around times when testing software. The flash download feature of J-Link is very efficient and allows fast flash programming. For
example, if a debugger splits the download image into several pieces, the flash
download software will collect the individual parts and perform the actual flash programming right before program execution. This avoids repeated flash programming. .
Moreover, the J-Link flash loaders make flash behave like RAM. This means that the
debugger only needs to select the correct device which enables the J-Link DLL to
automatically activate the correct flash loader if the debugger writes to a specific
memory address.
This also makes it very easy for debugger vendors to make use of the flash download
feature because almost no extra work is necessary on the debugger side since the
debugger does not have to differ between memory writes to RAM and memory writes
to flash.

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6.2

Licensing
No extra license required. The flash download feature can be used free of charge.

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6.3

CHAPTER 6

Flash download

Supported devices
J-Link supports download into the internal flash of a large number of microcontrollers. You can always find the latest list of supported devices on our website:
http://www.segger.com/jlink_supported_devices.html
In general, J-Link can be used with any ARM7/9/11, Cortex-M0/M1/M3/M4 and Cortex-A5/A8/R4 core even if it does not provide internal flash.
Furthermore, flash download is also available for all CFI-compliant external NORflash devices.

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6.4

Setup for various debuggers (internal flash)
The J-Link flash download feature can be used by different debuggers, such as IAR
Embedded Workbench, Keil MDK, GDB based IDEs, ... For different debuggers there
are different steps required to enable J-Link flash download. In this section, the
setup for different debuggers is explained.

6.4.1

IAR Embedded Workbench

Using the J-Link flash download feature in IAR EWARM is quite simple:
First, choose the right device in the project settings if not already done. The device
settings can be found at Project->Options->General Options->Target.

To use the J-Link flash loaders, the IAR flash loader has to be disabled. To disable the
IAR flash loader, the checkbox Use flash loader(s) at Project->Options->Debugger->Download has to be disabled, as shown below.

6.4.2

Keil MDK

To use the J-Link flash download feature in Keil MDK, the following steps need to be
performed:

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First, choose the device in the project settings if not already done. The device settings can be found at Project->Options for Target->Device.

To enable the J-Link flash loader J-Link / J-Trace at Project->Options for Target->Utilities has to be selected. It is important that "Update Target before Debugging" is unchecked since otherwise uVision tries to use its own flashloader.

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Then J-Link has to be selected as debugger. To select J-Link as debugger simply
choose J-Link / J-Trace from the list box which can be found at Project>Options for Target->Debug.

Now setup the Download Options at Project->Options for Target->Debug ->
Settings. Check Verify Code Download and Download to Flash as shown in the
screenshot below.

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6.4.3

Flash download

Mentor Sourcery CodeBench

To use the J-Link flash download feature in Mentor Sourcery CodeBench, the following steps need to be performed:
Current versions of Sourcery CodeBench do not pass the device name selected in
CodeBench to the J-Link DLL. Therefore a device override via J-Link settings file is
needed.
•
•
•

•

•

Copy the J-Link settings file template from
$JLINK_INST_DIR$\Samples\JLink\SettingsFiles\Sample.jlinksettings
to the directory where the CodeBench project is located.
Open the Sample.jlinksettings in a text editor and scroll to the [FLASH] section.
Change the line
Device="UNSPECIFIED"
to the device name that shall be selected (keep the quotation marks). A list of
valid
device
names
can
be
found
here:
http://www.segger.com/
jlink_supported_devices.html (List of known devices)
Change the line
Override = 0
to
Override = 1
Select the settings file to be used in Sourcery CodeBench:

Additional steps for enabling Flash Breakpoints feature
By default, Mentor Sourcery CodeBench does not allow the user to use the J-Link
unlimited number of breakpoints in flash feature, since it only allows hardware
breakpoints being set, by default. Enabling this feature requires an additional tweak
in the J-Link settings file:
•
•

•
•
•

6.4.4

Make sure that all steps from Mentor Sourcery CodeBench on page 218, to
enable flash download, have been performed.
Make sure that Sourcery CodeBench uses a J-Link DLL with version V4.85d or
later. If an earlier version is used, this tweak does not work.
To update the DLL used by CodeBench, copy the J-Link DLL from the J-Link
installation directory to:
C:\Tool\C\Mentor\CodeBench\bin\arm-none-eabi-jlinkarm.dll
Open the settings file in a text editor and scroll to the [BREAKPOINTS] section.
Add the line:
ForceImpTypeAny = 1
Make sure that CodeBench uses the settings file.

J-Link GDB Server

The configuration for the J-Link GDB Server is done by the .gdbinit file. The following command has to be added to the .gdbinit file to enable the J-Link flash download feature:
monitor flash device 

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 is the name of the device for which download into internal flash memory shall be enabled. For a list of supported devices, please refer to Supported
devices on page 214. For more information about the GDB monitor commands please
refer to J-Link GDB Server on page 83.

6.4.5

J-Link Commander

J-Link Commander supports downloading bin files into internal flash memory of popular microcontrollers. In the following, it is explained which steps are necessary to
prepare J-Link Commander for download into internal flash memory.

6.4.5.1 Preparing J-Link Commander for flash download
To configure J-Link Commander for flash download simply select the connected
device by typing in the following command:
exec device = 

 is the name of the device for which download into internal flash memory shall be enabled. For a list of supported devices, please refer to Supported
devices on page 214. In order to start downloading the binary data file into flash,
please type in the following command:
loadbin , 

 is the path of the binary data file which should be downloaded into the
flash. is the start address, the data file should be written to.

6.4.5.2 Converting non-bin files
As previously mentioned, J-Link Commander supports programming of bin files into
flash memory. If the data file to be programmed is in non-bin format (.hex, .mot,
.srec), the file needs to be converted into binary first. There are various free software utilities available which allow data file conversion. Another possibility is to use
J-Flash which is part of the J-Link software and documentation package. For converting data files, no J-Flash license is needed.
In order to convert a hex/mot/... file into a bin file using J-Flash, the following needs
to be done:
1.
2.
3.
4.
5.

Start J-Flash.
Click File | Open data file... to open the data file to be converted in J-Flash.
Click File | Save data file as...
Select Binary file (*.bin) as file type so J-Flash knows that the file shall be saved
as binary (bin) file.
Click Save.

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6.4.6

Flash download

J-Link RDI

The configuration for J-Link RDI is done via the J-Link RDI configuration dialog.

For more information about the J-Link RDI configuration dialog please refer to
UM08004, J-Link RDI User Guide, chapter Configuration dialog.

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6.5

Setup for various debuggers (CFI flash)
The setup for download into CFI-compliant memory is different from the one for
internal flash. Initialization of the external memory interface the CFI flash is connected to, is user's responsibility and is expected by the J-Link software to be done
prior to performing accesses to the specified CFI area. In this section, the setup for
different debuggers is explained.

6.5.1

IAR Embedded Workbench / Keil MDK

Using the J-Link flash download feature with IAR Embedded Workbench / Keil MDK is
quite simple:
First, start the debug session and open the J-Link Control Panel. In the tab "Settings"
you will find the location of the settings file.

Close the debug session and open the settings file with a text editor. Add the following lines to the file:
[CFI]
CFISize = 
CFIAddr = 
[GENERAL]
WorkRAMSize = 
WorkRAMAddr = 

After this the file should look similar to the sample in the following screenshot.

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Save the settings file and restart the debug session. Open the J-Link Control Panel
and verify that the "MemMap" tab shows the new settings for CFI flash and work RAM
area.

6.5.2

J-Link GDB Server

The configuration for the J-Link GDB Server is done by the .gdbinit file. The following commands have to be added to the .gdbinit file to enable the flash download
feature:
monitor WorkRAM = -
monitor flash CFI = -

For more information about the GDB monitor commands please refer to J-Link GDB
Server on page 83.

6.5.3

J-Link commander

J-Link Commander supports downloading bin files into external CFI flash memory. In
the following, it is explained which steps are necessary to prepare J-Link Commander
for download into external CFI flash memory based on a sample sequence for a ST
STM32F103ZE device:
r
speed 1000
exec setcfiflash 0x64000000 - 0x64FFFFFF
exec setworkram 0x20000000 - 0x2000FFFF
w4 0x40021014, 0x00000114 // RCC_AHBENR, FSMC clock enable
w4 0x40021018, 0x000001FD // GPIOD~G clock enable
w4 0x40011400, 0xB4BB44BB // GPIOD low config, NOE, NWE => Output, NWAIT => Input
w4 0x40011404, 0xBBBBBBBB // GPIOD high config, A16-A18
w4 0x40011800, 0xBBBBBBBB // GPIOE low config, A19-A23
w4 0x40011804, 0xBBBBBBBB // GPIOE high config, D5-D12
w4 0x40011C00, 0x44BBBBBB // GPIOF low config, A0-A5
w4 0x40011C04, 0xBBBB4444 // GPIOF high config, A6-A9
w4 0x40012000, 0x44BBBBBB // GPIOG low config, A10-A15
w4 0x40012004, 0x444B4BB4 // GPIOG high config, NE2 => output
w4 0xA0000008, 0x00001059 // CS control reg 2, 16-bit, write enable, Type: NOR flash
w4 0xA000000C, 0x10000505 // CS2 timing reg (read access)
w4 0xA000010C, 0x10000505 // CS2 timing reg (write access)
speed 4000
mem 0x64000000,100
loadbin C:\STMB672_STM32F103ZE_TestBlinky.bin,0x64000000
mem 0x64000000,100

6.5.3.1 Converting non-bin files
As previously mentioned, J-Link Commander supports programming of bin files into
flash memory. If the data file to be programmed is in non-bin format (.hex, .mot,
.srec), the file needs to be converted into binary first. There are various free soft-

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ware utilities available which allow data file conversion. Another possibility is to use
J-Flash which is part of the J-Link software and documentation package. For converting data files, no J-Flash license is needed.
In order to convert a hex/mot/... file into a bin file using J-Flash, the following needs
to be done:
1.
2.
3.
4.
5.

Start J-Flash.
Click File | Open data file... to open the data file to be converted in J-Flash.
Click File | Save data file as...
Select Binary file (*.bin) as file type so J-Flash knows that the file shall be saved
as binary (bin) file.
Click Save.

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6.6 Using the DLL flash loaders in custom applications
The J-Link DLL flash loaders make flash behave as RAM from a user perspective,
since flash programming is triggered by simply calling the J-Link API functions for
memory reading / writing. For more information about how to setup the J-Link API
for flash programming please refer to UM08002 J-Link SDK documentation (available
for SDK customers only).

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Chapter 7
Flash breakpoints

This chapter describes how the flash breakpoints feature of the DLL can be used in
different debugger environments.

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7.1

CHAPTER 7

Flash breakpoints

Introduction
The J-Link DLL supports a feature called flash breakpoints which allows the user to
set an unlimited number of breakpoints in flash memory rather than only being able
to use the hardware breakpoints of the device. Usually when using hardware breakpoints only, a maximum of 2 (ARM 7/9/11) to 8 (Cortex-A/R) breakpoints can be set.
The flash memory can be the internal flash memory of a supported microcontroller or
external CFI-compliant flash memory. In the following sections the setup for different
debuggers for use of the flash breakpoints feature is explained.

How do breakpoints work?
There are basically 2 types of breakpoints in a computer system: Hardware breakpoints and software breakpoints. Hardware breakpoints require a dedicated hardware
unit for every breakpoint. In other words, the hardware dictates how many hardware
breakpoints can be set simultaneously. ARM 7/9 cores have 2 breakpoint units (called
"watchpoint units" in ARM's documentation), allowing 2 hardware breakpoints to be
set. Hardware breakpoints do not require modification of the program code. Software
breakpoints are different: The debugger modifies the program and replaces the
breakpointed instruction with a special value. Additional software breakpoints do not
require additional hardware units in the processor, since simply more instructions are
replaced. This is a standard procedure that most debuggers are capable of, however,
this usually requires the program to be located in RAM.

What is special about software breakpoints in flash?
Flash breakpoints allows setting delete of an unlimited number of breakpoints even if
the user application is not located in RAM. On modern microcontrollers this is the
standard scenario because on most microcontrollers the internal RAM is not big
enough to hold the complete application. When replacing instructions in flash memory this requires re-programming of the flash which takes much more time than simply replacing a instruction when debugging in RAM. The J-Link flash breakpoints
feature is highly optimized for fast flash programming speed and in combination with
the instruction set simulation only re-programs flash that is absolutely necessary.
This makes debugging in flash using flash breakpoints almost as flawless as debugging in RAM.

What performance can I expect?
Flash algorithm, specially designed for this purpose, sets and clears flash breakpoints
extremely fast; on microcontrollers with fast flash the difference between software
breakpoints in RAM and flash is hardly noticeable.

How is this performance achieved?
We have put a lot of effort in making flash breakpoints really usable and convenient.
Flash sectors are programmed only when necessary; this is usually the moment execution of the target program is started. A lot of times, more than one breakpoint is
located in the same flash sector, which allows programming multiple breakpoints by
programming just a single sector. The contents of program memory are cached,
avoiding time consuming reading of the flash sectors. A smart combination of software and hardware breakpoints allows us to use hardware breakpoints a lot of times,
especially when the debugger is source level-stepping, avoiding re-programming the
flash in these situations. A built-in instruction set simulator further reduces the number of flash operations which need to be performed. This minimizes delays for the
user, while maximizing the life time of the flash. All resources of the ARM microcontroller are available to the application program, no memory is lost for debugging.

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7.2

Licensing
In order to use the flash breakpoints feature a separate license is necessary for each
J-Link. For some devices J-Link comes with a device-based license and some J-Link
models also come with a full license for flash breakpoints but the normal J-Link
comes without any licenses. For more information about licensing itself and which
devices have a device-based license, please refer to Licensing on page 49.

7.2.1

Free for evaluation and non-commercial use

In general, the unlimited flash breakpoints feature of the J-Link DLL can be used
free of charge for evaluation and non-commercial use.
If used in a commercial project, a license needs to be purchased when the evaluation
is complete. There is no time limit on the evaluation period. This feature allows setting an unlimited number of breakpoints even if the application program is located in
flash memory, thereby utilizing the debugging environment to its fullest.

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7.3

CHAPTER 7

Flash breakpoints

Supported devices
J-Link supports flash breakpoints for a large number of microcontrollers. You can
always find the latest list of supported devices on our website:
http://www.segger.com/jlink_supported_devices.html
In general, J-Link can be used with any ARM7/9/11, Cortex-M0/M1/M3/M4 and Cortex-A5/A8/R4 core even if it does not provide internal flash.
Furthermore, flash breakpoints are also available for all CFI compliant external NORflash devices.

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7.4

Setup & compatibility with various debuggers

7.4.1

Setup

In compatible debuggers, flash breakpoints work if the J-Link flash loader works and
a license for flash breakpoints is present. No additional setup is required. The flash
breakpoint feature is available for internal flashes and for external CFI-flash. For
more information about how to setup various debuggers for flash download, please
refer to Setup for various debuggers (internal flash) on page 215. Whether flash
breakpoints are available can be verified using the J-Link control panel:

7.4.2

Compatibility with various debuggers

Flash breakpoints can be used in all debugger which use the proper J-Link API to set
breakpoints. Compatible debuggers/ debug interfaces are:
•
•
•
•
•
•

IAR Embedded Workbench
Keil MDK
GDB-based debuggers
Freescale Codewarrior
Mentor Graphics Sourcery CodeBench
RDI-compliant debuggers

Incompatible debuggers / debug interfaces:
•

Rowley Crossworks

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7.5
Q:
A:

CHAPTER 7

Flash breakpoints

FAQ
Why can flash breakpoints not be used with Rowley Crossworks?
Because Rowley Crossworks does not use the proper J-Link API to set breakpoints.
Instead of using the breakpoint-API, Crossworks programs the debug hardware
directly, leaving J-Link no choice to use its flash breakpoints.

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Chapter 8
J-Flash SPI

This chapter describes J-Flash SPI and J-Flash SPI CL, which are seperate software
(executables) which allows direct programming of SPI flashes, without any additional
hardware. Both, J-Flash SPI and J-Flash SPI CL are part of the J-Link software and
documentation package which is available free of charge.
This chapter assumes that you already possess working knowledge of the J-Link
device.

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CHAPTER 8

8.1

J-Flash SPI

Introduction
The following chapter introduces J-Flash SPI, highlights some of its features, and lists
its requirements on host and target systems.

8.1.1

What is J-Flash SPI?

J-Flash SPI is a stand-alone flash programming software for PCs running Microsoft
Windows, which allows direct programming of SPI flashes, without any additional
hardware. The following Microsoft Windows versions are supported:
•
•
•
•
•
•
•
•
•
•
•

Microsoft Windows
Microsoft Windows
Microsoft Windows
Microsoft Windows
Microsoft Windows
Microsoft Windows
Microsoft Windows
Microsoft Windows
Microsoft Windows
Windows 8
Windows 8 x64

2000
XP
XP x64
2003
2003 x64
Vista
Vista x64
7
7 x64

J-Flash SPI has an intuitive user interface and makes programming flash devices convenient. J-Flash SPI requires a J-Link or Flasher to interface to the hardware. It is
able to program all kinds of SPI flashes, even if the CPU they are connected to, is not
supported by J-Link / Flasher because J-Flash SPI communicates directly with the SPI
flash bypassing all other components of the hardware.

8.1.2

J-Flash SPI CL (Windows, Linux, Mac)

J-Flash SPI CL is a commandline-only version of the J-Flash SPI programming tool.
The command line version is included in the J-Link Software and Documentation
Package for Windows, Linux and Mac (cross-platform). Except from the missing GUI,
J-Flash SPI CL is identical to the normal version.
The commands, used to configure / control J-Flash SPI CL, are exactly the same as
for the command line interface of the J-Flash SPI GUI version. For further information, please refer to Command Line Interface on page 243.

8.1.3
•
•
•
•
•
•

8.1.4

Features
Directly communicates with the SPI flash via SPI protocol, no MCU in between
needed.
Programming of all kinds of SPI flashes is supported.
Can also program SPI flashes that are connected to CPUs that are not supported
by J-Link.
Verbose logging of all communication.
.hex, .mot, .srec, and .bin support.
Intuitive user interface.

Requirements

8.1.4.1 Host
J-Flash SPI requires a PC running Microsoft Windows 2000 or Windows XP with a free
USB port dedicated to a J-Link. A network connection is required only if you want to
use J-Flash SPI together with J-Link Remote Server.

8.1.4.2 Target
The flash device must be an SPI flash that supports standard SPI protocols.

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8.2

Licensing
The following chapter provides an overview of J-Flash SPI related licensing options.

8.2.1

Introduction

A J-Link PLUS, ULTRA+, PRO or Flasher ARM/PRO is required to use J-Flash SPI. No
additional license is required / available.

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8.3

J-Flash SPI

Getting Started
This chapter presents an introduction to J-Flash SPI. It provides an overview of the
included sample projects and describes the menu structure of J-Flash SPI in detail.

8.3.1

Setup

For J-Link setup procedure required in order to work with J-Flash SPI, please refer to
chapter Setup on page 139

8.3.1.1 What is included?
The following table shows the contents of all subdirectories of the J-Link software and
documentation pack with regard to J-Flash SPI:
Directory

Contents

.

The J-Flash SPI application. Please refer to the J-Link
manual for more information about the other J-Link
related tools.

.\Doc

Contains the J-Flash SPI documentation and the other JLink related manuals.

Table 8.1: J-Flash SPI directory structure

8.3.2

Using J-Flash SPI for the first time

Start J-Flash SPI from the Windows Start menu. The main window will appear, which
contains a log window at the bottom and the Project window of a default project on
the left. The application log will initially display:
•
•
•

The version and time of compilation for the application.
The version and time of compilation for the J-Link DLL.
The location of the default project.

The Project window contains an overview of the current project settings (initially, a
default project is opened).

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8.3.3

Menu structure

The main window of J-Flash SPI contains seven drop-down menus (File, Edit, View,
Target, Options, Window, Help). Any option within these drop-down menus that is
followed by a three period ellipsis (...), is an option that requires more information
before proceeding.

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File menu elements
Command
Open data file...

Merge data file

Save data file
Save data file as...
New Project
Open Project...
Save Project
Save Project as...
Close Project
Recent Files >
Recent Projects >
Exit

Description
Opens a data file that may be used to flash the target
device. The data file must be an Intel HEX file, a Motorola
S file, or a Binary file (.hex, .mot, .srec, or .bin).
Merges two data files (.hex, .mot, .srec, or .bin). All
gaps will be filled with FF. Find below a short example of
merging two data files named, File0.bin and File1.bin into
File3.bin.
File0.bin --> Addr 0x0200 - 0x02FF
File1.bin --> Addr 0x1000 - 0x13FF
Merge File0.bin & File1.bin
0x0200 - 0x02FF Data of File0.bin
0x0300 - 0x0FFF gap (will be filled with 0xFF if image is
saved as *.bin file)
0x1000 - 0x13FF Data of File1.bin
Can be saved in new data file (File3.bin).
Saves the data file that currently has focus.
Saves the data file that currently has focus using the
name and location given.
Creates a new project using the default settings.
Opens a project file. Note that only one project file may
be open at a time. Opening a project will close any other
project currently open.
Saves a project file.
Saves a project file using the name and location given.
Closes a project file.
Contains a list of the most recently open data files.
Contains a list of the most recently open project files.
Exits the application.

Table 8.2: File menu elements

Edit menu elements
Command
Relocate...

Delete range...
Eliminate blank
areas...

Description
Relocates the start of the data file to the supplied hex
offset from the current start location.
Deletes a range of values from the data file, starting and
ending at given addresses. The End address must be
greater than the Start address otherwise nothing will be
done.
Eliminates blank regions within the data file.

Table 8.3: Edit menu elements

View menu elements
Command
Log
Project

Description
Opens and/or brings the log window to the active window.
Opens and/or brings the project window to the active
window.

Table 8.4: View menu elements

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Target menu elements
Command
Connect
Disconnect

Test >

Erase sectors
Erase chip
Program
Program & Verify

Auto

Verify

Read back >

Description
Creates a connection through the J-Link using the configuration options set in the Project settings... of the
Options drop-down menu.
Disconnects a current connection that has been made
through the J-Link.
Two test functions are implemented: "Generates test
data" generates data which can be used to test if the
flash can be programmed correctly. The size of the generated data file can be defined.
"Tests up/download speed" writes data of an specified
size to a defined address, reads the written data back
and measures the up- and download speed.
Erases all selected flash sectors.
Erases the entire chip.
Programs the chip using the currently active data file.
Programs the chip using the currently active data file and
then verifies that it was written successfully.
The Auto command performs a sequence of steps. It connects to the device, erases sectors and programs the chip
using the currently active data file before the written
data is finally verified. The range of sectors to be erased
can be configured through the Flash tab of the Project
settings dialog and through the Global settings dialog.
Verifies the data found on the chip with the data file.
Reads back the data found on the chip and creates a new
data file to store this information. There are three ways
in which the data can be read back. The Selected sectors
identified on the Flash tab of the Project Settings... found
in the Options drop-down menu may be read back. The
Entire chip may be read back. A specified Range... may
be read back.

Table 8.5: Target menu elements

Options menu elements
Command

Project settings...

Global settings...

Description
Location of the project settings that are displayed in the
snapshot view found in the Project window of the J-Flash
SPI application. Furthermore various settings needed to
locate the J-Link and pass specified commands needed
for chip initialization.
Settings that influence the general operation of J-Flash
SPI.

Table 8.6: Options menu elements

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Window menu elements
Command
Cascade
Tile Horizontal
Tile Vertical

Description
Arranges all open windows, one above the other, with the
active window at the top.
Tiles the windows horizontally with the active window at
the top.
Tiles the windows vertically with the active window at the
left.

Table 8.7: Window menu elements

Help menu elements
Command
J-Link User’s Guide
About...

Description
Shows the J-Link User’s Guide in a PDF viewer such as
Adobe Reader.
J-Flash SPI and company information.

Table 8.8: Help menu elements

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8.4

Settings
The following chapter provides an overview of the program settings. Both general
and per project settings are considered.

8.4.1

Project Settings

Project settings are available from the Options menu in the main window or by using
the ALT-F7 keyboard shortcut.

8.4.1.1 General Settings
This dialog is used to choose the connection to J-Link. The J-Link can either be
connected over USB or via TCP/IP to the host system. Refer to the J-Link manual for
more information regarding the operation of J-Link and J-Link TCP/IP Server.

8.4.1.1.1 USB
If this option is checked, J-Flash SPI will connect to J-Link over the USB port. You
may change the device number if you want to connect more than one J-Link to your
PC. The default device number is 0. For more information about how to use multiple
J-Links on one PC, please see also the chapter "Working with J-Link" of the J-Link
User’s Guide.

8.4.1.1.2 TCP/IP
If this option is selected, J-Flash SPI will connect to J-Link via J-Link TCP/IP Server.
You have to specify the hostname of the remote system running the J-Link TCP/IP
Server.

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8.4.1.2 Interface
This dialog is used to configure the SPI interface settings like SPI communication
speed etc.

8.4.1.2.1 Interface Speed
Specifies the SPI communication speed J-Link uses to communicate with the SPI
flash.

8.4.1.3 Flash Settings
This dialog is used to select and configure the parameters of the SPI flash that JFlash SPI will connect to. Examples for flash parameters are: Sector size (Smallest
erasable unit), page size (smallest programmable unit), Flash ID, etc. There is also
the option to try to auto-detect the connected flash device. The latter option will
prompt J-Flash SPI to try to identify the flash by its Flash ID, looking up in an
internal list of known flash devices.

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8.4.2

Global Settings

Global settings are available from the Options menu in the main window.

8.4.2.1 Operation
You may define the behavior of some operations such as "Auto" or "Program & Verify".

8.4.2.1.1 Disconnect after each operation
If this option is checked, connection to the target will be closed at the end of each
operation.

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8.4.2.1.2 Automatically unlock sectors
If this option is checked, all sectors affected by an erase or program operation will be
automatically unlocked if necessary.

8.4.2.1.3 Perform blank check
If this option is checked, a blank check is performed before any program operation to
examine if the affected flash sectors are completely empty. The user will be asked to
erase the affected sectors if they are not empty.

8.4.2.1.4 Skip blank areas on read
If this option is checked, a blank check is performed before any read back operation
to examine which flash areas need to be read back from target. This improves performance of read back operations since it minimizes the amount of data to be transferred via JTAG and USB.

8.4.2.2 Logging
You may set some logging options to customize the log output of J-Flash SPI.

8.4.2.2.1 General log level
This specifies the log level of J-Flash SPI. Increasing log levels result in more information logged in the log window.

8.4.2.2.2 Enable J-Link logfile
If this option is checked, you can specify a file name for the J-Link logfile. The J-Link
logfile differs from the log window output of J-Flash SPI. It does not log J-Flash SPI
operations performed. Instead of that, it logs the J-Link ARM DLL API functions called
from within J-Flash SPI.

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8.5

Command Line Interface
This chapter describes the J-Flash SPI command line interface. The command line
allows using J-Flash SPI in batch processing mode and other advanced uses.

8.5.1

Overview

In addition to its traditional Windows graphical user interface (GUI), J-Flash SPI supports a command line mode as well. This makes it possible to use J-Flash SPI for
batch processing purposes. All important options accessible from the menus are
available in command line mode as well. If you provide command line options, JFlash SPI will still start its GUI, but processing will start immediately.
The screenshot below shows the command line help dialog, which is displayed if you
start J-Flash SPI in a console window with JFlashSPI.exe -help or JFlashSPI.exe
-?

8.5.2

Command line options

This section lists and describes all available command line options. Some options
accept additional parameters which are enclosed in angle brackets, e.g. . If these parameters are optional they are enclosed in square brackets too,
e.g. []. Neither the angel nor the square brackets must be typed on the
command line, they are used here only to denote (optional) parameters. Also, note
that a parameter must follow immediately after the option,
e.g. JFlash.exe -openprjC:\Projects\Default.jflash.

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The command line options are evaluated in the order they are passed to J-Flash, so
please ensure that a project and data file has already been opened when evaluating a
command line option which requires this.
It is recommended to always use -open[,] to make sure the
right data file is opened.
All command line options return 0 if the processing was successful. A return value
unequal 0 means that an error occured.
Option
-?
-auto
-connect
-delrange,
-disconnect
-eliminate
-erasechip
-erasesectors
-exit
-help

-merge
-merge.bin,

-open[,]

-openprj
-program
-programverify
-readchip
-readrange,
-save[,]

-saveas[,,]
-saveprj
-saveprjas
-verify
-usb
-ip
-ip

Description
Displays help dialog.
Erases, program and verify target.
Connects to target.
Deletes data in the given range.
Disconnects from target.
Eliminates blank areas in data file.
Erases the entire flash chip.
Erases all sectors.
Exits application.
Displays help dialog.
Merges a given file with the one currently
opened.
Note that when passing a .bin file via this command, also the start-address where it shall be
merged the file currently openend in J-Flash
SPI must be given, too, since .bin files do not
contain any address information.
Open a data file. Please note that the
 parameter applies only if the data
file is a *.bin file.
Open an existing project file. This will also
automatically open the data file that has been
recently used with this project.
Program target.
Program and verify target.
Read entire flash chip.
Read specified range of target memory.
Save the current data file. Please note that the
parameters , apply only if
the data file is a *.bin file or *.c file.
Save the current data file into the specified
file. Please note that the parameters
,  apply only if the data file
is a *.bin file or *.c file.
Save the current project.
Save the current project in the specified file.
Verify target memory.
Overrides connection settings to USB.
Overrides connection settings to IP.

Table 8.9: J-Flash SPI command line options

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8.5.3

Batch processing

J-Flash SPI can be used for batch processing purposes. All important options are
available in command line mode as well. When providing command line options, the
application does not wait for manual user input. All command line operations will be
performed in exactly the order they are passed. So, for example issuing a program
command before a project has been opened will cause the program command to fail.
The example batchfile below will cause J-Flash SPI to perform the following operations:
1.
2.
3.
4.

Open project C:\Projects\Default.jflash
Open bin file C:\Data\data.bin and set start address to 0x100000
Perform "Auto" operation in J-Flash (by default this performs erase, program,
verify)
Close J-Flash SPI

The return value will be checked and in case of an error message will be displayed.
Adapt the example according to the requirements of your project.
@ECHO OFF
ECHO Open a project and data file, start auto processing and exit
JFlashSPI.exe -openprjC:\Projects\Default.jflash -openC:\Data\data.bin,0x100000 auto -exit
IF ERRORLEVEL 1 goto ERROR
goto END
:ERROR
ECHO J-Flash SPI:
pause

Error!

:END

Starting J-Flash minimized
Adapt this example call to start J-Flash SPI minimized:
start /min /wait "J-Flash" "JFlashSPI.exe"
\
-openC:\Data\data.bin,0x100000 -auto -exit

-openprjC:\Projects\Default.jflash

Note that every call of JFlashSPI.exe has to be completed with the -exit option,
otherwise the execution of the batch file stops and the following commands will not
be processed.

8.5.4

Programming multiple targets in parallel

In order to program multiple targets in parallel using J-Flash SPI, the following is
needed:
•

Multiple J-Flash SPI projects, each configured to connect to a specific J-Link /
Flasher (emulator to connect to is selected by serial number).

The easiest way is to setup the appropriate project once and then make multiple copies of this project. Now modify the Connection to J-Link setting in each project, in
order to let J-Flash SPI connect to the different programmers as shown in the screenshot below:
Find below a small sample which shows how to program multiple targets in parallel:

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@ECHO OFF
ECHO Open first project which is configured to connect to the first J-Link. Open data
file, start auto processing and exit
open JFlashSPI.exe -openprjC:\Projects\Project01.jflash -openC:\Data\data.bin,
0x100000 -auto -exit
IF ERRORLEVEL 1 goto ERROR
ECHO Open second project which is configured to connect to the second J-Link. Open
data file, start auto processing and exit
open JFlashSPI.exe -openprjC:\Projects\Project02.jflash -openC:\Data\data.bin,
0x100000 -auto -exit
IF ERRORLEVEL 1 goto ERROR
ECHO Open third project which is configured to connect to the third J-Link. Open data
file, start auto processing and exit
open JFlashSPI.exe -openprjC:\Projects\Project03.jflash -openC:\Data\data.bin,
0x100000 -auto -exit
IF ERRORLEVEL 1 goto ERROR
goto END
:ERROR
ECHO J-Flash SPI:
pause

Error!

:END

Note that every call of JFlashSPI.exe has to completed with the -exit option, otherwise stops the execution of the batch file and the following commands will not be
processed.

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8.6

Create a new J-Flash SPI project
This chapter contains information about the required steps for the setup of a new JFlash SPI project.

8.6.1

Creating a new J-Flash SPI project

Creating a new project for J-Flash is pretty simple. In the following, all necessary
steps to create a project file are explained.
1.
2.

Select File -> New Project to create a new project with default settings.
Open the Project Settings context menu. Select Options -> Project Settings
to open the Project settings dialog and select the type of connection to J-Link.

3.

Define the SPI communication speed. The default settings work without any
problem for most targets, but to achieve the last quantum of performance, manual tuning may be necessary.

4.

Open the Flash and either select Automatically detect SPI flash or manually
enter the flash parameters.
Save the project (File -> Save Project) and test it.

5.

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8.6.2

J-Flash SPI

Serial number programming

J-Flash SPI supports programming of serial numbers. In order to use the serial number programming feature, the J-Flash SPI project to be used as well as some files in
the working folder (depending on the configuration) need to be configured first.
In general, J-Flash SPI supports two ways of programming a serial number into the
target:
1.
2.

Programming continuous serial numbers. Serial number is 1-4 bytes in size. Start
serial number, increment, serial number size and address have to be configured in the
J-Flash SPI project production settings.
Programming custom serial numbers from a serial number list file. Start line of
the serial number list file, line increment, serial number size and address is configured in J-Flash SPI production project settings. Serial number list file needs to
be specified and created by user.

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8.7

Device specifics
This chapter gives some additional information about specific devices.

8.7.1

SPI flashes with multiple erase commands

Some SPI flashes support multiple erase commands that allow to erase different
units on the flash. For example some flashes provide a sector erase (erase 4 KB
units) and a block erase (erase 16 KB or 64 KB units) command. In general, it is up
to the user which command to use, as the EraseSector command can be overridden
by the user. When manually changing the SectorErase command in the Options ->
Project settings... -> Flash tab, make sure that the SectorSize parameter
matches the command being used.

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8.8

J-Flash SPI

Target systems

8.8.1

Which flash devices can be programmed?

In general, all kinds of SPI flash can be programmed. Since all flash parameters are
configurable, also flashes with non-standard command sets can be programmed.

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8.9

Performance
The following chapter lists programming performance for various SPI flash devices.

8.9.1

Performance values

In direct programming mode (J-Link directly connects to the pins of the SPI flash),
the programming speed is mainly limited by the SPI communication speed, the USB
speed of J-Link (if a Full-Speed or Hi-Speed based J-Link is used) and the maximum
programming speed of the flash itself.
For most SPI flash devices, in direct programming mode speeds of >= 50 KB/s can
be achieved.

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8.10 Background information
This chapter provides some background information about specific parts of the JFlash SPI software.

8.10.1 SPI interface connection
For direct SPI flash programming, J-Link needs to be wired to the SPI flash in a specific way. For more information about the pinout for the J-Link SPI target interface,
please refer to UM08001, J-Link J-Trace User Guide. The minimum pins that need to
be connected, are: VTref, GND, SPI-CLK, MOSI, MISO. If other components on the
target hardware need to be kept in reset while programming the SPI flash (e.g. a
CPU etc.), nRESET also needs to be connected.

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8.11 Support
The following chapter provides advises on troubleshooting for possible typical
problems and information about how to contact our support.

8.11.1 Troubleshooting
8.11.1.1 Typical problems
Target system has no power
Meaning:
J-Link could not measure the target (flash) reference voltage on pin 1 of its connector.
Remedy:
The target interface of J-Link works with level shifters to be as flexible as possible.
Therefore, the reference I/O voltage the flash is working with also needs to be connected to pin 1 of the J-Link connector.

Programming / Erasing failed
Meaning:
The SPI communication speed may be too high for the given signal quality.
Remedy:
Try again with a slower speed. If it still fails, check the quality of the SPI signals.

Failed to verify Flash ID
Meaning:
J-Link could not verify the ID of the connected flash.
Remedy:
Check the Flash ID entered in the flash parameters dialog, for correctness.

8.11.2 Contacting support
If you experience a J-Flash SPI related problem and advice given in the sections
above does not help you to solve it, you may contact our support. In this case, please
provide us with the following information:
•
•
•
•

A detailed description of the problem.
The relevant log file and project file. In order to generate an expressive log file,
set the log level to "All messages" (see section Global Settings on page 241 for
information about changing the log level in J-Flash SPI).
The relevant data file as a .hex or .mot file (if possible).
The processor and flash types used.

Once we received this information we will try our best to solve the problem for you.
Our contact address is as follows:
SEGGER Microcontroller GmbH & Co. KG
In den Weiden 11
D-40721 Hilden
Germany
Tel.+49 2103-2878-0
Fax.+49 2103-2878-28
Email: support@segger.com
Internet: http://www.segger.com

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Chapter 9
RDI

RDI (Remote Debug Interface) is a standard defined by ARM, trying to standardize a
debugger / debug probe interface. It is defined only for cores that have the same
CPU register set as ARM7 CPUs. This chapter describes how to use the RDI DLL which
comes with the J-Link software and documentation package. The J-Link RDI DLL
allows the user to use J-Link with any RDI-compliant debugger and IDE.

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9.1

RDI

Introduction
Remote Debug Interface (RDI) is an Application Programming Interface (API) that
defines a standard set of data structures and functions that abstract hardware for
debugging purposes. J-Link RDI mainly consists of a DLL designed for ARM cores to
be used with any RDI compliant debugger. The J-Link DLL feature flash download and
flash breakpoints can also be used with J-Link RDI.

Host (PC)
RDI compliant +
Debugger
elf.gif

Data
File

(e.g. elf)

J-Link RDI DLL

USB

J-Link

JTAG

ARM

9.1.1
•
•
•
•
•

Features
Can be used with every RDI compliant debugger.
Easy to use.
Flash download feature of J-Link DLL can be used.
Flash breakpoints feature of J-Link DLL can be used.
Instruction set simulation (improves debugging performance).

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9.2

Licensing
In order to use the J-Link RDI software a separate license is necessary for each JLink. For some devices J-Link comes with a device-based license and some J-Link
models also come with a full license for J-Link RDI. The normal J-Link however,
comes without any licenses. For more information about licensing itself and which
devices have a device-based license, please refer to Licensing on page 49.

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9.3

RDI

Setup for various debuggers
The J-Link RDI software is an ARM Remote Debug Interface (RDI) for J-Link. It makes
it possible to use J-Link with any RDI compliant debugger. Basically, J-Link RDI consists of a additional DLL (JLinkRDI.dll) which builds the interface between the RDI
API and the normal J-Link DLL. The JLinkRDI.dll itself is part of the J-Link software
and documentation package.

9.3.1

IAR Embedded Workbench IDE

J-Link RDI can be used with IAR Embedded Workbench for ARM.

9.3.1.1 Supported software versions
J-Link RDI has been tested with IAR Embedded Workbench IDE version 4.40. There
should be no problems with other versions of IAR Embedded Workbench IDE. All
screenshots are taken from IAR Embedded Workbench version 4.40.
Note:
Since IAR EWARM V5.30 J-Link is fully and natively supported by EWARM,
so RDI is no longer needed.

9.3.1.2 Configuring to use J-Link RDI
1.

Start the IAR Embedded Workbench and open the tutor example project or the
desired project. This tutor project has been preconfigured to use the simulator driver.
In order to run the J-Link RDI, the driver needs to be changed.

2.

Choose Project | Options and select the Debugger category. Change the

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Driver option to RDI.

3.

Go to the RDI page of the Debugger options, select the manufacturer driver
( JLinkRDI.dll ) and click OK .

4.

Now an extra menu, RDI, has been added to the menu bar.
Choose RDI | Configure to configure the J-Link. For more information about the
generic setup of J-Link RDI, please refer to Configuration on page 274.

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9.3.1.3 Debugging on Cortex-M3 devices
The RDI protocol has only been specified by ARM for ARM 7/9 cores. For Cortex-M
there is no official extension of the RDI protocol regarding the register assignement,
that has been approved by ARM. Since IAR EWARM version 5.11 it is possible to use
J-Link RDI for Cortex-M devices because SEGGER and IAR have come to an agreement regarding the RDI register assignment for Cortex-M. The following table lists
the register assignment for RDI and Cortex-M:
Register
Index

0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
16
17
18
19
20
21
22
23
24
25
26
27
28

Assigned register

R0
R1
R2
R3
R4
R5
R6
R7
R8
R9
R10
R11
R12
MSP / PSP (depending on mode)
R14 (LR)
R15 (PC)
XPSR
APSR
IPSR
EPSR
IAPSR
EAPSR
IEPSR
PRIMASK
FAULTMASK
BASEPRI
BASEPRI_MAX
CFBP (CONTROL/FAULT/BASEPRI/PRIMASK)

Table 9.1: Cortex-M register mapping for IAR + J-Link RDI

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9.3.2

ARM AXD (ARM Developer Suite, ADS)

9.3.2.1 Software version
The JLinkRDI.dll has been tested with ARM’s AXD version 1.2.0 and 1.2.1.
There should be no problems with other versions of ARM’s AXD. All screenshots are
taken from ARM’s AXD version 1.2.0.

9.3.2.2 Configuring to use J-Link RDI
1.

Start the ARM debugger and select Options | Configure Target.... This opens the
Choose Target dialog box:

2.

Press the Add Button to add the JLinkRDI.dll .

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3.

Now J-Link RDI is available in the Target Environments list.

4.

Select J-Link and press OK to connect to the target via J-Link. For more information about the generic setup of J-Link RDI, please refer to Configuration on
page 274. After downloading an image to the target board, the debugger window
looks as follows:

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9.3.3

ARM RVDS (RealView developer suite)

9.3.3.1 Software version
J-Link RDI has been tested with ARM RVDS version 2.1 and 3.0. There should be no
problems with earlier versions of RVDS (up to version v3.0.1). All screenshots are
taken from ARM’s RVDS version 2.1.
Note:
RVDS version 3.1 does not longer support RDI protocol to communicate
with the debugger.

9.3.3.2 Configuring to use J-Link RDI
1.

Start the Real View debugger:

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2.

Select File | Connection | Connect to Target .

3.

In the Connection Control dialog use the right mouse click on the first item and
select Add/Remove/Edit Devices .

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4.

Now select Add DLL to add the JLinkRDI.dll . Select the installation path of the
software, for example:
C:\Program Files\SEGGER\JLinkARM_V350g\JLinkRDI.dll

5.

After adding the DLL, an additional Dialog opens and asks for description: (These
values are voluntary, if you do not want change them, just click OK ) Use the following values and click on OK , Short Name: JLinkRDI Description: J-Link
RDI Interface .

6.

Back in the RDI Target List Dialog, select JLink-RDI and click Configure . For
more information about the generic setup of J-Link RDI, please refer to Configuration on page 274.

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7.
8.

RDI

Click the OK button in the configuration dialog. Now close the RDI Target List
dialog. Make sure your target hardware is already connected to J-Link.
In the Connection control dialog, expand the JLink ARM RDI Interface and
select the ARM_0 Processor. Close the Connection Control Window.

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9.

Now the RealView Debugger is connected to J-Link.

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10. A project or an image is needed for debugging. After downloading, J-Link is used
to debug the target.

9.3.4

GHS MULTI

9.3.4.1 Software version
J-Link RDI has been tested with GHS MULTI version 4.07. There should be no problems with other versions of GHS MULTI. All screenshots are taken from GHS MULTI
version 4.07.

9.3.4.2 Configuring to use J-Link RDI
1.

Start Green Hills Software MULTI integrated development environment. Click Connect | Connection Organizer to open the Connection Organizer.

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2.

Click Method | New in the Connection Organizer dialog.

3.

The Create a new Connection Method will be opened. Enter a name for your
configuration in the Name field and select Custom in the Type list. Confirm your
choice with the Create... button.

4.

The Connection Editor dialog will be opened. Enter rdiserv in the Server field
and enter the following values in the Arguments field:
-config -dll 
Note that JLinkRDI.dll and JLinkARM.dll must be stored in the same directory.
If the standard J-Link installation path or another path that includes spaces has
been used, enclose the path in quotation marks.
Example:
-config -dll "C:\Program Files\SEGGER\JLinkARM_V350g\JLinkRDI.dll"
Refer to GHS manual "MULTI: Configuring Connections for ARM Targets", chapter
"ARM Remote Debug Interface (rdiserv) Connections" for a complete list of possible arguments.

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5.

Confirm the choices by clicking the Apply button after the Connect button.

6.

The J-Link RDI Configuration dialog will open. For more information about the
generic setup of J-Link RDI, please refer to Configuration on page 274.
Click the OK button to connect to the target. Build the project and start the
debugger. Note that at least one action (for example step or run ) has to be performed in order to initiate the download of the application.

7.

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9.3.5

KEIL MDK (µVision IDE)

9.3.5.1 Software version
J-Link has been tested with KEIL MDK 3.34. There should be no problems with other
versions of KEIL µVision. All screenshots are taken from MDK 3.34.

9.3.5.2 Configuring to use J-Link RDI
Start KEIL uVision and open the project.

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Select Project | Options for Target ’’ to open the project options
dialog and select the Debug tab.

Choose RDI Interface Driver from the list as shown above and click the Settings
button. Select the location of JLinkRDI.dll in Browse for RDI Driver DLL field.
and click the Configure RDI Driver button.

The J-Link RDI Configuration dialog will be opened.For more information about the
generic setup of J-Link RDI, please refer to Configuration on page 274.

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After finishing configuration, the project can be built ( Project | Build Target) and
the debugger can be started ( Debug | Start/Stop debug session ).

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9.4

RDI

Configuration
This section describes the generic setup of J-Link RDI (same for all debuggers) using
the J-Link RDI configuration dialog.

9.4.1

Configuration file JLinkRDI.ini

All settings are stored in the file JLinkRDI.ini . This file is located in the same directory as JLinkRDI.dll.

9.4.2

Using different configurations

It can be desirable to use different configurations for different targets. If this is the
case, a new folder needs to be created and the JLinkARM.dll as well as the
JLinkRDI.dll needs to be copied into it.
Project A needs to be configured to use JLinkRDI.dll A in the first folder, project B
needs to be configured to use the DLL in the second folder. Both projects will use
separate configuration files, stored in the same directory as the DLLs they are using.
If the debugger allows using a project-relative path (such as IAR EWARM: Use for
example $PROJ_DIR$\RDI\ ), it can make sense to create the directory for the DLLs
and configuration file in a subdirectory of the project.

9.4.3

Using mutliple J-Links simulatenously

Same procedure as using different configurations. Each debugger session will use
their own instance of the JLinkRDI.dll .

9.4.4

Configuration dialog

The configuration dialog consists of several tabs making the configuration of J-Link
RDI very easy.

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9.4.4.1 General tab

Connection to J-Link
This setting allows the user to configure how the DLL should connect to the J-Link.
Some J-Link models also come with an Ethernet interface which allows to use an
emulator remotely via TCP/IP connection.

License (J-Link RDI License managment)
1.

The License button opens the J-Link RDI License management dialog. J-Link
RDI requires a valid license.

2.

Click the Add license button and enter your license. Confirm your input by click-

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ing the OK button.

3.

The J-Link RDI license is now added.

9.4.4.2 Init tab

Macro file
A macro file can be specified to load custom settings to configure J-Link RDI with
advanced commands for special chips or operations. For example, a macro file can be
used to initialize a target to use the PLL before the target application is downloaded,
in order to speed up the download.

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Comands in the macro file
Command
SetJTAGSpeed(x);
Delay(x);
Reset(x);
Go();
Halt();
Read8(Addr);
Read16(Addr);
Read32(Addr);
Verify8(Addr, Data);
Verify16(Addr, Data);
Verify32(Addr, Data);
Write8(Addr, Data);
Write16(Addr, Data);
Write32(Addr, Data);
WriteVerify8(Addr, Data);
WriteVerify16(Addr, Data);
WriteVerify32(Addr, Data);
WriteRegister(Reg, Data);
WriteJTAG_IR(Cmd);
WriteJTAG_DR(nBits, Data);

Description

Sets the JTAG speed, x = speed in kHz (0=Auto)
Waits a given time,
x = delay in milliseconds
Resets the target,
x = delay in milliseconds
Starts the ARM core
Halts the ARM core
Reads a 8/16/32 bit value,
Addr = address to read (as hex value)
Verifies a 8/16/32 bit value,
Addr = address to verify (as hex value)
Data = data to verify (as hex value)
Writes a 8/16/32 bit value,
Addr = address to write (as hex value)
Data = data to write (as hex value)
Writes and verifies a 8/16/32 bit value,
Addr = address to write (as hex value)
Data = data to write (as hex value)
Writes a register
Writes the JTAG instruction register
Writes the JTAG data register

Table 9.2: Macro file commands

Example of macro file
/*********************************************************************
*
*
Macro file for J-LINK RDI
*
**********************************************************************
* File:
LPC2294.setup
* Purpose: Setup for Philips LPC2294 chip
**********************************************************************
*/
SetJTAGSpeed(1000);
Reset(0);
Write32(0xE01FC040, 0x00000001); // Map User Flash into Vector area at (0-3f)
Write32(0xFFE00000, 0x20003CE3); // Setup CS0
Write32(0xE002C014, 0x0E6001E4); // Setup PINSEL2 Register
SetJTAGSpeed(2000);

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9.4.4.3 JTAG tab

JTAG speed
This allows the selection of the JTAG speed. There are basically three types of speed
settings (which are explained below):
•
•
•

Fixed JTAG speed
Automatic JTAG speed
Adaptive clocking

For more information about the different speed settings supported by J-Link, please
refer to JTAG Speed on page 166.

JTAG scan chain with multiple devices
The JTAG scan chain allows to specify the instruction register organization of the target system. This may be needed if there are more devices located on the target system than the ARM chip you want to access or if more than one target system is
connected to one J-Link at once.

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9.4.4.4 Flash tab

Enable flash programming
This checkbox enables flash programming. Flash programming is needed to use
either flash download or flash breakpoints.
If flash programming is enabled you must select the correct flash memory and flash
base address. Furthermore it is necessary for some chips to enter the correct CPU
clock frequence.

Cache flash contents
If enabled, the flash content is cached by the J-Link RDI software to avoid reading
data twice and to speed up the transfer between debugger and target.

Allow flash download
This allows the J-Link RDI software to download program into flash. A small piece of
code will be downloaded and executed in the target RAM which then programs the
flash memory. This provides flash loading abilities even for debuggers without a
build-in flash loader.
An info window can be shown during download displaying the current operation.
Depending on your JTAG speed you may see the info window only very short.

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9.4.4.5 Breakpoints tab

Use software breakpoints
This allows to set an unlimited number of breakpoints if the program is located in
RAM by setting and resetting breakpoints according to program code.

Use flash breakpoints
This allows to set an unlimited number of breakpoints if the program is located either
in RAM or in flash by setting and resetting breakpoints according to program code.
An info window can be displayed while flash breakpoints are used showing the current operation. Depending on your JTAG speed the info window may hardly to be
seen.

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9.4.4.6 CPU tab

Instruction set simulation
This enables instruction set simulation which speeds up single stepping instructions
especially when using flash breakpoints.

Reset strategy
This defines the way J-Link RDI should handle resets called by software.
J-Link supports different reset strategies. This is necessary because there is no single
way of resetting and halting an ARM core before it starts to execute instructions.
For more information about the different reset strategies which are supported by JLink and why different reset strategies are necessary, please refer to Reset strategies
on page 181.

9.4.4.7 Log tab
A log file can be generated for the J-Link DLL and for the J-Link RDI DLL. This log
files may be useful for debugging and evaluating. They may help you to solve a problem yourself, but is also needed by customer support help you.
Default path of the J-Link log file: c:\JLinkARM.log
Default path of the J-Link RDI log file: c:\JLinkRDI.log

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Example of logfile content:
060:028 (0000) Logging started @ 2005-10-28 07:36
060:028 (0000) DLL Compiled: Oct 4 2005 09:14:54
060:031 (0026) ARM_SetMaxSpeed - Testing speed 3F0F0F0F 3F0F0F0F 3F0F0F0F 3F0F0F0F
3F0F0F0F 3F0F0F0F 3F0F0F0F 3F0F0F0F 3F0F0F0F 3F0F0F0F 3F0F0F0F 3F0F0F0FAuto JTAG
speed: 4000 kHz
060:059 (0000) ARM_SetEndian(ARM_ENDIAN_LITTLE)
060:060 (0000) ARM_SetEndian(ARM_ENDIAN_LITTLE)
060:060 (0000) ARM_ResetPullsRESET(ON)
060:060 (0116) ARM_Reset(): SpeedIsFixed == 0 -> JTAGSpeed = 30kHz >48> >2EF>
060:176 (0000) ARM_WriteIceReg(0x02,00000000)
060:177 (0016) ARM_WriteMem(FFFFFC20,0004) -- Data: 01 06 00 00 - Writing 0x4 bytes
@ 0xFFFFFC20 >1D7>
060:194 (0014) ARM_WriteMem(FFFFFC2C,0004) -- Data: 05 1C 19 00 - Writing 0x4 bytes
@ 0xFFFFFC2C >195>
060:208 (0015) ARM_WriteMem(FFFFFC30,0004) -- Data: 07 00 00 00 - Writing 0x4 bytes
@ 0xFFFFFC30 >195>
060:223 (0002) ARM_ReadMem (00000000,0004)JTAG speed: 4000 kHz -- Data: 0C 00 00 EA
060:225 (0001) ARM_WriteMem(00000000,0004) -- Data: 0D 00 00 EA - Writing 0x4 bytes
@ 0x00000000 >195>
060:226 (0001) ARM_ReadMem (00000000,0004) -- Data: 0C 00 00 EA
060:227 (0001) ARM_WriteMem(FFFFFF00,0004) -- Data: 01 00 00 00 - Writing 0x4 bytes
@ 0xFFFFFF00 >195>
060:228 (0001) ARM_ReadMem (FFFFF240,0004) -- Data: 40 05 09 27
060:229 (0001) ARM_ReadMem (FFFFF244,0004) -- Data: 00 00 00 00
060:230 (0001) ARM_ReadMem (FFFFFF6C,0004) -- Data: 10 01 00 00
060:232 (0000) ARM_WriteMem(FFFFF124,0004) -- Data: FF FF FF FF - Writing 0x4 bytes
@ 0xFFFFF124 >195>
060:232 (0001) ARM_ReadMem (FFFFF130,0004) -- Data: 00 00 00 00
060:233 (0001) ARM_ReadMem (FFFFF130,0004) -- Data: 00 00 00 00
060:234 (0001) ARM_ReadMem (FFFFF130,0004) -- Data: 00 00 00 00
060:236 (0000) ARM_ReadMem (FFFFF130,0004) -- Data: 00 00 00 00
060:237 (0000) ARM_ReadMem (FFFFF130,0004) -- Data: 00 00 00 00
060:238 (0001) ARM_ReadMem (FFFFF130,0004) -- Data: 00 00 00 00
060:239 (0001) ARM_ReadMem (FFFFF130,0004) -- Data: 00 00 00 00
060:240 (0001) ARM_ReadMem (FFFFF130,0004) -- Data: 00 00 00 00
060:241 (0001) ARM_WriteMem(FFFFFD44,0004) -- Data: 00 80 00 00 - Writing 0x4 bytes
@ 0xFFFFFD44 >195>
060:277 (0000) ARM_WriteMem(00000000,0178) -- Data: 0F 00 00 EA FE FF FF EA ...
060:277 (0000) ARM_WriteMem(000003C4,0020) -- Data: 01 00 00 00 02 00 00 00 ... Writing 0x178 bytes @ 0x00000000
060:277 (0000) ARM_WriteMem(000001CC,00F4) -- Data: 30 B5 15 48 01 68 82 68 ... Writing 0x20 bytes @ 0x000003C4
060:277 (0000) ARM_WriteMem(000002C0,0002) -- Data: 00 47
060:278 (0000) ARM_WriteMem(000002C4,0068) -- Data: F0 B5 00 27 24 4C 34 4D ... Writing 0xF6 bytes @ 0x000001CC
060:278 (0000) ARM_WriteMem(0000032C,0002) -- Data: 00 47
060:278 (0000) ARM_WriteMem(00000330,0074) -- Data: 30 B5 00 24 A0 00 08 49 ... Writing 0x6A bytes @ 0x000002C4
060:278 (0000) ARM_WriteMem(000003B0,0014) -- Data: 00 00 00 00 0A 00 00 00 ... Writing 0x74 bytes @ 0x00000330
060:278 (0000) ARM_WriteMem(000003A4,000C) -- Data: 14 00 00 00 E4 03 00 00 ... Writing 0x14 bytes @ 0x000003B0
060:278 (0000) ARM_WriteMem(00000178,0054) -- Data: 12 4A 13 48 70 B4 81 B0 ... Writing 0xC bytes @ 0x000003A4
060:278 (0000) ARM_SetEndian(ARM_ENDIAN_LITTLE)
060:278 (0000) ARM_SetEndian(ARM_ENDIAN_LITTLE)
060:278 (0000) ARM_ResetPullsRESET(OFF)
060:278 (0009) ARM_Reset(): - Writing 0x54 bytes @ 0x00000178 >3E68>
060:287 (0001) ARM_Halt(): **** Warning: Chip has already been halted.
...

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9.5

Semihosting
Semihosting is a mechanism for ARM targets to communicate input/output requests
from application code to a host computer running a debugger.
It effectively allows the target to do disk operations and console I/O and is used primarily for flash loaders with ARM debuggers such as AXD.

9.5.1

Overview

Semihosting
Semihosting is a mechanism for ARM targets to communicate input/output requests
from application code to a host computer running a debugger. This mechanism is
used to allow functions in the C library, such as printf() and scanf() , to use the
screen and keyboard of the host rather than having a screen and keyboard on the
target system.
This is useful because development hardware often does not have all the input and
output facilities of the final system. Semihosting allows the host computer to provide
these facilities.
Semihosting is also used for Disk I/O and flash programming; a flash loader uses
semihosting to load the target program from disk.
Semihosting is implemented by a set of defined software interrupt (SWI) operations.
The application invokes the appropriate SWI and the debug agent then handles the
SWI exception. The debug agent provides the required communication with the host.
In many cases, the semihosting SWI will be invoked by code within library functions.

Usage of semihosting
The application can also invoke the semihosting SWI directly. Refer to the C library
descriptions in the ADS Compilers and Libraries Guide for more information on support for semihosting in the ARM C library.
Semihosting is not used by all tool chains; most modern tool chains (such as IAR)
use different mechanisms to achive the same goal.
Semihosting is used primarily by ARM’s tool chain and debuggers, such as AXD.
Since semihosting has been used primarily by ARM, documents published by ARM are
the best source of add. information.
For further information on semihosting and the C libraries, see the "C and C++
Libraries" chapter in ADS Compilers and Libraries Guide. Please see also the "Writing
Code for ROM" chapter in ADS Developer Guide.

9.5.2

The SWI interface

The ARM and Thumb SWI instructions contain a field that encodes the SWI number
used by the application code. This number can be decoded by the SWI handler in the
system. See the chapter on exception handling in ADS Developer Guide for more
information on SWI handlers.
Semihosting operations are requested using a single SWI number. This leaves the
other SWI numbers available for use by the application or operating system. The SWI
used for semihosting is:
0x123456 in ARM state
0xAB
in Thumb state
The SWI number indicates to the debug agent that the SWI
In order to distinguish between operations, the operation
other parameters are passed in a block that is pointed to by
in r0, either as an explicit return value or as a pointer to
result is returned, assume that r0 is corrupted.

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is a semihosting request.
type is passed in r0. All
r1. The result is returned
a data block. Even if no

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The available semihosting operation numbers passed in r0 are allocated as follows:
0x00 to 0x31 These are used by ARM.
0x32 to 0xFF These are reserved for future use by ARM.
0x100 to 0x1FF Reserved for applications.

9.5.2.1 Changing the semihosting SWI numbers
It is strongly recommended that you do not change the semihosting SWI numbers
0x123456 (ARM) or 0xAB (Thumb). If you do so you must:
•
•

9.5.3

change all the code in your system, including library code, to use the new SWI
number.
reconfigure your debugger to use the new SWI number.

Implementation of semihosting in J-Link RDI

When using J-Link RDI in default configuration, semihosting is implemented as follows:
•
•
•
•

A breakpoint / vector catch is set on the SWI vector.
When this breakpoint is hit, J-Link RDI examines the SWI number.
If the SWI is recognized as a semihosting SWI, J-Link RDI emulates it and transparently restarts execution of the application.
If the SWI is not recognized as a semihosting SWI, J-Link RDI halts the processor
and reports an error. (See Unexpected / unhandled SWIs on page 285)

9.5.3.1 DCC semihosting
J-Link RDI does not support using the debug communications channel for semihosting.

9.5.4

Semihosting with AXD

This semihosting mechanism can be disabled or changed by the following debugger
internal variables:

$semihosting_enabled
Set this variable to 0 to disable semihosting. If you are debugging an application running from ROM, this allows you to use an additional watchpoint unit.
Set this variable to 1 to enable semihosting. This is the default.
Set this variable to 2 to enable Debug Communications Channel (DCC) semihosting.
The S bit in $vector_catch has no effect unless semihosting is disabled.

$semihosting_vector
This variable controls the location of the breakpoint set by J-Link RDI to detect a
semihosted SWI. It is set to the SWI entry in the exception vector table () by default.

9.5.4.1 Using SWIs in your application
If your application requires semihosting as well as having its own SWI handler, set
$semihosting_vector to an address in your SWI handler. This address must point to
an instruction that is only executed if your SWI handler has identified a call to a
semihosting SWI. All registers must already have been restored to whatever values
they had on entry to your SWI handler.

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9.5.5

Unexpected / unhandled SWIs

When an unhandled SWI is detected by J-Link RDI, the message box below is shown.

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Chapter 10
RTT

SEGGER’s Real Time Terminal (RTT) is a technology for interactive user I/O in embedded applications. It combines the advantages of SWO and semihosting at very high
performance.

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10.1 Introduction
With RTT it is possible to output information from the target microcontroller as well
as sending input to the application at a very high speed without affecting the target's
real time behavior.
SEGGER RTT can be used with any J-Link model and any supported target processor
which allows background memory access, which are Cortex-M and RX targets.
RTT supports multiple channels in both directions, up to the host and down to the
target, which can be used for different purposes and provide the most possible freedom to the user.
The default implementation uses one channel per direction, which are meant for
printable terminal input and output. With the J-Link RTT Viewer this channel can be
used for multiple "virtual" terminals, allowing to print to multiple windows (e.g. one
for standard output, one for error output, one for debugging output) with just one
target buffer. An additional up (to host) channel can for example be used to send
profiling or event tracing data.

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10.2 How RTT works
10.2.1 Target implementation
Real Time Terminal uses a SEGGER RTT Control Block structure in the target's memory to manage data reads and writes.
The control block contains an ID to make it findable in memory by a connected J-Link
and a ring buffer structure for each available channel, describing the channel buffer
and its state.
The maximum number of available channels can be configured at compile time and
each buffer can be configured and added by the application at run time. Up and down
buffers can be handled separately.
Each channel can be configured to be blocking or non-blocking. In blocking mode the
application will wait when the buffer is full, until all memory could be written, resulting in a blocked application state but preventing data from getting lost. In non-blocking mode only data which fits into the buffer, or none at all, will be written and the
rest will be discarded. This allows running in real-time, even when no debugger is
connected. The developer does not have to create a special debug version and the
code can stay in place in a release application.

10.2.2 Locating the Control Block
When RTT is active on the host computer, either by using RTT directly via an application like RTT Viewer or by connecting via Telnet to an application which is using JLink, like a debugger, J-Link automatically searches for the SEGGER RTT Control
Block in the target's known RAM regions. The RAM regions or the specific address of
the Control Block can also be set via the host applications to speed up detection or if
the block cannot be found automatically.

10.2.3 Internal structures
There may be any number of "Up Buffer Descriptors" (Target -> Host), as well as any
number of "Down Buffer Descriptors" (Host -> Target). Each buffer size can be configured individually.
The gray areas in the buffers are the areas that contain valid data.
For Up buffers, the Write Pointer is written by the target, the Read Pointer is written
by the debug probe (J-Link, Host).

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When Read and Write Pointers point to the same element, the buffer is empty. This
assures there is never a race condition. The image shows the simplified structure in
the target.

10.2.4 Requirements
SEGGER RTT does not need any additional pin or hardware, despite a J-Link connected via the standard debug port to the target. It does not require any configuration of the target or in the debugging environment and can even be used with varying
target speeds.
RTT can be used in parallel to a running debug session, without intrusion, as well as
without any IDE or debugger at all.

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10.2.5 Performance
The performance of SEGGER RTT is significantly higher than any other technology
used to output data to a host PC. An average line of text can be output in one microsecond or less. Basically only the time to do a single memcopy().

10.2.6 Memory footprint
The RTT implementation code uses ~500 Bytes of ROM and 24 Bytes ID + 24 Bytes
per channel for the control block in RAM. Each channel requires some memory for the
buffer. The recommended sizes are 1 kByte for up channels and 16 to 32 Bytes for
down channels depending on the load of in- / output.

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10.3 RTT Communication
Communication with the RTT implementation on the target can be done with different
applications. The functionality can even be integrated into custom applications using
the J-Link SDK.
Using RTT in the target application is made easy. The implementation code is freely
available for download and can be integrated into any existing application. To communicate via RTT any J-Link can be used.
The simple way to communicate via the Terminal (Channel 0) is to create a connection to localhost:19021 with a Telnet client or similar, when a connection to J-Link
(e.g. via a debug session) is active.
The J-Link Software Package comes with some more advanced applications, which
demonstrates RTT functionality for different purposes.

10.3.1 J-Link RTT Viewer

J-Link RTT Viewer is a Windows GUI application to use all features of RTT in one
application. It supports:
•
•
•
•
•

Displaying terminal output of Channel 0.
Up to 16 virtual Terminals on Channel 0.
Sending text input to Channel 0.
Interpreting text control codes for colored text and controling the Terminal.
Logging data on Channel 1.

10.3.1.1 RTT Viewer Startup
Make sure J-Link and target device are connected and powered up.
Start RTT Viewer by opening the executable (JLinkRTTViewer.exe) from the installation folder of the J-Link Software or the start menu.
The Configuration Dialog will pop up.
Configure the Connection Settings as described below and click OK. The connection
settings and all in app configuration will be saved for the next start of RTT Viewer.

10.3.1.2 Connection Settings
RTT Viewer can be used in two modes:
•

Stand-alone, opening an own connection to J-Link and target.

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•

In attach mode, connecting to an existing J-Link connection of a debugger.

Stand-alone connection settings
In stand-alone mode RTT Viewer needs to know some settings of J-Link and target
device.
Select USB or TCP/IP as the connection to J-Link. For USB a specific J-Link serial
number can optionally be entered, for TCP/IP the IP or hostname of the J-Link has to
be entered.
Select the target device to connect to. This allows J-Link to search in the known RAM
of the target.
Select the target interface and its speed.
If known, enter the address of the RTT Control Block in the target application. Otherwise leave as 0 for auto detection.

Attaching to a connection
In attach mode RTT Viewer does not need any settings. Select Existing Session.
For attach mode a connection to J-Link has to be opened and configured by another
application like a debugger or simply J-Link Commander. If the RTT Control Block
cannot be found automatically, configuration of its location has to be done by the
debugger / application.

10.3.1.3 The Terminal Tabs
RTT Viewer allows displaying the output of Channel 0 in different "virtual" Terminals.
The
target
application
can
switch
between
SEGGER_RTT_SetTerminal() and SEGGER_RTT_TerminalOut().

terminals

with

RTT Viewer displays the Terminals in different tabs.

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All Terminals
The All Terminals tab displays the complete output of RTT Channel 0 and can display
the user input (Check Input -> Echo input... -> Echo to "All Terminals").
Each output line is prefixed by the Terminal it has been sent to. Additionally, output
on Terminal 1 is shown in red, output on Terminals 2 - 15 in grey.

Terminal 0 - 15
Each tab Terminal 0 - Terminal 15 displays the output which has been sent to this
Terminal. The Terminal tabs interpret and display Text Control Codes as sent by the
application to show colored text or erase the screen.
By default, if the RTT application does not set a Terminal Id, the output is displayed
in Terminal 0.
The Teminal 0 tab can additionally display the user input. (Check Input -> Echo
input... -> Echo to "Terminal 0")
Each Terminal tab can be shown or hidden via the menu Terminals -> Terminals... or
their respective shortcuts as described below.

10.3.1.4 Sending Input
RTT Viewer supports sending user input to RTT Down Channel 0 which can be read by
the target application with SEGGER_RTT_GetKey() and SEGGER_RTT_Read().
Input can be entered in the text box below the Teminal Tabs.
RTT Viewer can be configured to directly send each character while typing or buffer it
until Enter is pressed (Menu Input -> Sending...).
In stand-alone mode RTT Viewer can retry to send input, in case the target input
buffer is full, until all data could be sent to the target via Input -> Sending... ->
Block if FIFO full.

10.3.1.5 Logging Data
Additionally to displaying output of Channel 0, RTT Viewer can log data which is sent
on RTT Channel 1 into a file. This can for example be used to sent instrumentalized
event tracing data. The data log file contains header and footer and the binary data
as received from the application.
Logging can be started via Data -> Start Logging....
Note:

Logging is only available in stand-alone mode.

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10.3.1.6 Menus and Shortcuts
Menu entry

Contents

Shortcut

File

Closes connection and exit RTT
Viewer.

Alt-Q

-> Add next terminal

Opens the next available Terminal
Tab.

Alt-A

-> Close active terminal

Closes the active Terminal Tab.

Alt-C

-> Show Log

Opens or closes the Log Tab.

Alt-L

--> Terminal 0 - 9

Opens or closes the Terminal Tab.

Alt-0 Alt-9

--> Terminal 10 - 15

Opens or closes the Terminal Tab.

-> Exit
Terminals

Terminals -> Terminals...

Input
-> Clear input field

Clears the input field without sending
entered data.

Button
’Clear’

Input -> Sending...
--> Send on Input

If selected, entered input will be sent
directly to the target while typing.

--> Send on Enter

If selected, entered input will be sent
when pressing Enter.

--> Block if FIFO full

If checked, RTT Viewer will retry to
send all input to the target when the
target buffer is full.

Input -> End of line...
-->
-->
-->
-->

Windows format (CR+LF)
Unix format (LF)
Mac format (CR)
None

Selects the end of line character to
be sent on Enter.

Input -> Echo input...
--> Echo to "All Terminals"

If checked, sent input will be displayed in the All Terminals Tab.

--> Echo to "Terminal 0"

If checked, sent input will be displayed in the Terminal Tab 0.

Data
-> Start logging...

Starts logging data of Channel 1 to a
file.

F5

-> Stop logging

Stops loggind data and close the file.

Shift-F5

Shows version info of RTT Viewer.

F12

Help
-> About...

Table 10.1: RTT Viewer Menus and Shortcuts

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Menu entry

RTT

Contents

Shortcut

-> J-Link Manual...

Opens the J-Link Manual PDF file.

F11

-> RTT Webpage...

Opens the RTT webpage.

F10

Right-Click on Tab
-> Clear Terminal

Clears the displayed output of this
Terminal Tab.

Table 10.1: RTT Viewer Menus and Shortcuts

10.3.1.7 Using "virtual" Terminals in RTT
For virtual Terminals the target application needs only Up Channel 0. This is especially important on targets with low RAM.
If nothing is configured, all data is sent to Terminal 0.
The Teminal to output all following via Write, WriteString or printf can be set with
SEGGER_RTT_SetTerminal() .
Output of only one string
SEGGER_RTT_TerminalOut().

via

a

specific

Terminal

can

be

done

with

The sequences sent to change the Terminal are interpreted by RTT Viewer. Other
applications like a Telnet Client will ignore them.

10.3.1.8 Using Text Control Codes
RTT allows using Text Control Codes (ANSI escape codes) to configure the display of
text.
RTT Viewer supports changing the text color and background color and can erase the
Terminal.
These Control Codes are pre-defined in the RTT application and can easily be used in
the application.

Example 1:
SEGGER_RTT_WriteString(0,
RTT_CTRL_RESET"Red: "
RTT_CTRL_TEXT_BRIGHT_RED"This text is red. "
RTT_CTRL_TEXT_BLACK""
RTT_CTRL_BG_BRIGHT_RED"This background is red. "
RTT_CTRL_RESET"Normal text again.");

\
\
\
\

Example 2:
SEGGER_RTT_printf(0, "%sTime:%s%s %.7d\n",
RTT_CTRL_RESET,
RTT_CTRL_BG_BRIGHT_RED,
RTT_CTRL_TEXT_BRIGHT_WHITE,
1111111
);
//
// Clear the terminal.
// The first line will not be shown after this command.
//
SEGGER_RTT_WriteString(0, RTT_CTRL_CLEAR);
SEGGER_RTT_printf(0, "%sTime: %s%s%.7d\n",
RTT_CTRL_RESET,
RTT_CTRL_BG_BRIGHT_RED,
RTT_CTRL_TEXT_BRIGHT_WHITE,
2222222
);

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10.3.2 RTT Client
J-Link RTT Client acts as a Telnet client, but automatically tries to reconnect to a JLink connection when a debug session is closed.
The J-Link RTT Client is part of the J-Link Software and Documentation Pack for Windows, Linux and OS X and can be used for simple RTT use cases.

10.3.3 RTT Logger
With J-Link RTT Logger, data from Up-Channel 1 can be read and logged to a file. This
channel can for example be used to send performance analysis data to the host.
J-Link RTT Logger opens a dedicated connection to J-Link and can be used standalone, without running a debugger.
The application is part of the J-Link Software and Documentation Pack for Windows,
Linux and OS X.
The source of J-Link RTT Logger can be used as a starting point to integrate RTT in
other PC applications, like debuggers, and is part of the J-Link SDK.

10.3.4 RTT in other host applications
RTT can also be integrated in any other PC application like a debugger or a data visualizer in either of two ways.
1.
2.

The application can establish a socket connection to the RTT Telnet Server which
is opened on localhost:19021 when a J-Link connection is active.
The application creates its own connection to J-Link and uses the J-Link RTT API
which is part of the J-Link SDK to directly configure and use RTT.

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10.4 Implementation
The SEGGER RTT implementation code is written in ANSI C and can be integrated into
any embedded application by simply adding the available sources.
RTT can be used via a simple and easy to use API. It is even possible to override the
standard printf() functions to be used with RTT. Using RTT reduces the time taken for
output to a minimum and allows printing debug information to the host computer
while the application is performing time critical real time tasks.
The implementation code also includes a simple version of printf() which can be used
to write formatted strings via RTT. It is smaller than most standard library printf()
implementations and does not require heap and only a configureable ammount of
stack.
The SEGGER RTT implementation is fully configureable at compile time with pre-processor defines. The number of channels, the size of the default channels can be set.
Reading and writing can be made task-safe with definable Lock() and Unlock() routines.

10.4.1 API functions
The following API functions are available in the RTT Implementation. To use them
SEGGER_RTT.h has to be included in the calling sources.

10.4.1.1 SEGGER_RTT_ConfigDownBuffer()
Description
Configure or add a down buffer by specifying its name, size and flags.

Prototype
int SEGGER_RTT_ConfigDownBuffer (unsigned BufferIndex, const char* sName,
char* pBuffer, int BufferSize, int Flags);

Parameters
Parameter
BufferIndex
sName
pBuffer
BufferSize
Flags

Meaning

Index of the buffer to configure. Must be lower than
SEGGER_RTT_MAX_NUM_DOWN_CHANNELS.
Pointer to a 0-terminated string to be displayed as the name of the
channel.
Pointer to a buffer used by the channel.
Size of the buffer in Bytes.
Flags of the channel (blocking or non-blocking).

Table 10.2: SEGGER_RTT_ConfigDownBuffer() parameter list

Return value
>= 0
< 0

O.K.
Error.

Example
//
// Configure down channel 1
//
SEGGER_RTT_ConfigDownChannel(1, "DataIn", &abDataIn[0], sizeof(abDataIn),
SEGGER_RTT_MODE_NO_BLOCK_SKIP);

Additional information
Once a channel is configured only the flags of the channel should be changed.

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10.4.1.2 SEGGER_RTT_ConfigUpBuffer()
Description
Configure or add an up buffer by specifying its name, size and flags.

Prototype
int SEGGER_RTT_ConfigUpBuffer (unsigned BufferIndex, const char* sName,
char* pBuffer, int BufferSize, int Flags);

Parameters
Parameter
BufferIndex
sName
pBuffer
BufferSize
Flags

Meaning

Index of the buffer to configure. Must be lower than
SEGGER_RTT_MAX_NUM_UP_CHANNELS.
Pointer to a 0-terminated string to be displayed as the name of the
channel.
Pointer to a buffer used by the channel.
Size of the buffer in Bytes.
Flags of the channel (blocking or non-blocking).

Table 10.3: SEGGER_RTT_ConfigUpBuffer() parameter list

Return value
>= 0
< 0

O.K.
Error.

Example
//
// Configure up channel 1 to work in blocking mode
//
SEGGER_RTT_ConfigUpChannel(1, "DataOut", &abDataOut[0], sizeof(abDataOut),
SEGGER_RTT_MODE_BLOCK_IF_FIFO_FULL);

Additional information
Once a channel is configured only the flags of the channel should be changed.

10.4.1.3 SEGGER_RTT_GetKey()
Description
Reads one character from SEGGER RTT buffer 0. Host has previously stored data
there.

Prototype
int SEGGER_RTT_GetKey (void);

Return value
< 0
>= 0

No character available (empty buffer).
Character which has been read (0 - 255).

Example
int c;
c = SEGGER_RTT_GetKey();
if (c == ’q’) {
exit();
}

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10.4.1.4 SEGGER_RTT_HasKey()
Description
Checks if at least one character for reading is available in SEGGER RTT buffer. 0

Prototype
int SEGGER_RTT_HasKey (void);

Return value
0
1

No characters are available to be read.
At least one character is available in the buffer.

Example
if (SEGGER_RTT_HasKey()) {
int c = SEGGER_RTT_GetKey();
}

10.4.1.5 SEGGER_RTT_Init()
Description
Initializes the RTT Control Block.

Prototype
void SEGGER_RTT_Init (void);

Additional information
Should be used in RAM targets, at start of the application.

10.4.1.6 SEGGER_RTT_printf()
Description
Send a formatted string to the host.

Prototype
int SEGGER_RTT_printf (unsigned BufferIndex, const char * sFormat, ...)

Parameters
Parameter
BufferIndex
sFormat

Meaning

Index of the up channel to sent the string to.
Pointer to format string, followed by arguments for conversion.

Table 10.4: SEGGER_RTT_printf() parameter list

Return value
>= 0
< 0

Number of bytes which have been sent.
Error.

Example
SEGGER_RTT_printf(0, "SEGGER RTT Sample. Uptime: %.10dms.", /*OS_Time*/ 890912);
// Formatted output on channel 0: SEGGER RTT Sample. Uptime: 890912ms.

Additional information
(1) Conversion specifications have following syntax:
•

%[flags][FieldWidth][.Precision]ConversionSpecifier

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(2) Supported flags:
•
•
•

-: Left justify within the field width
+: Always print sign extension for signed conversions
0: Pad with 0 instead of spaces. Ignored when using '-'-flag or precision

(3) Supported conversion specifiers:
•
•
•
•
•
•

c: Print the argument as one char
d: Print the argument as a signed integer
u: Print the argument as an unsigned integer
x: Print the argument as an hexadecimal integer
s: Print the string pointed to by the argument
p: Print the argument as an 8-digit hexadecimal integer. (Argument shall be a
pointer to void.)

10.4.1.7 SEGGER_RTT_Read()
Description
Read characters from any RTT down channel which have been previously stored by
the host.

Prototype
int SEGGER_RTT_Read (unsigned BufferIndex, char* pBuffer, unsigned
BufferSize);

Parameters
Parameter
BufferIndex
pBuffer
BufferSize

Meaning

Index of the down channel to read from.
Pointer to a character buffer to store the read characters.
Number of bytes available in the buffer.

Table 10.5: SEGGER_RTT_Read() parameter list

Return value
>= 0

Number of bytes that have been read.

Example
char acIn[4];
int NumBytes = sizeof(acIn);
NumBytes = SEGGER_RTT_Read(0, &acIn[0], NumBytes);
if (NumBytes) {
AnalyzeInput(acIn);
}

10.4.1.8 SEGGER_RTT_SetTerminal()
Description
Set the "virtual" terminal to send following data on channel 0.

Prototype
void SEGGER_RTT_SetTerminal(char TerminalId);

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Parameters
Parameter
TerminalId

Meaning

Id of the virtual terminal (0-9).

Table 10.6: SEGGER_RTT_SetTerminal() parameter list

Example
//
// Send a string to terminal 1 which is used as error out.
//
SEGGER_RTT_SetTerminal(1); // Select terminal 1
SEGGER_RTT_WriteString(0, "ERROR: Buffer overflow");
SEGGER_RTT_SetTerminal(0); // Reset to standard terminal

Additional information
All following data which is sent via channel 0 will be printed on the set terminal until
the next change.

10.4.1.9 SEGGER_RTT_TerminalOut()
Description
Send one string to a specific "virtual" terminal.

Prototype
int SEGGER_RTT_TerminalOut (char TerminalID, const char* s);

Parameters
Parameter
TerminalId
s

Meaning

Id of the virtual terminal (0-9).
Pointer to 0-terminated string to be sent.

Table 10.7: SEGGER_RTT_TerminalOut() parameter list

Return value
>= 0

Number of bytes sent to the terminal.

Example
//
// Sent a string to terminal 1 without changing the standard terminal.
//
SEGGER_RTT_TerminalOut(1, "ERROR: Buffer overflow.");

Additional information
SEGGER_RTT_TerminalOut does not affect following data which is sent via channel 0.

10.4.1.10SEGGER_RTT_Write()
Description
Send data to the host on an RTT channel.

Prototype
int SEGGER_RTT_Write (unsigned BufferIndex, const char* pBuffer, unsigned
NumBytes);

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Parameters
Parameter
BufferIndex
pBuffer
NumBytes

Meaning

Index of the up channel to send data to.
Pointer to data to be sent.
Number of bytes to send.

Table 10.8: SEGGER_RTT_Write() parameter list

Return value
>= 0

Number of bytes which have been sent.

Additional information
With SEGGER_RTT_Write() all kinds of data, not only printable one can be sent.

10.4.1.11SEGGER_RTT_WaitKey()
Description
Waits until at least one character is avaible in SEGGER RTT buffer 0. Once a character
is available, it is read and returned.

Prototype
int SEGGER_RTT_WaitKey (void);

Return value
>= 0

Character which has been read (0 - 255).

Example
int c = 0;
do {
c = SEGGER_RTT_WaitKey();
} while (c != ’c’);

10.4.1.12SEGGER_RTT_WriteString()
Description
Write a 0-terminated string to an up channel via RTT.

Prototype
int SEGGER_RTT_WriteSting (unsigned BufferIndex, const char* s);

Parameters
Parameter
BufferIndex
s

Meaning

Index of the up channel to send string to.
Pointer to 0-terminated string to be sent.

Table 10.9: SEGGER_RTT_WriteString() parameter list

Return value
>= 0

Number of bytes which have been sent.

Example
SEGGER_RTT_WriteString(0, "Hello World from your target.\n");

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10.4.2 Configuration defines
10.4.2.1 RTT configuration
SEGGER_RTT_MAX_NUM_DOWN_BUFFERS
Maximum number of down (to target) channels.

SEGGER_RTT_MAX_NUM_UP_BUFFERS
Maximum number of up (to host) cahnnels.

BUFFER_SIZE_DOWN
Size of the buffer for default down channel 0.

BUFFER_SIZE_UP
Size of the buffer for default up channel 0.

SEGGER_RTT_PRINT_BUFFER_SIZE
Size of the buffer for SEGGER_RTT_printf to bulk-send chars.

SEGGER_RTT_LOCK()
Locking routine to prevent interrupts and task switches from within an RTT operation.

SEGGER_RTT_UNLOCK()
Unlocking routine to allow interrupts and task switches after an RTT operation.

SEGGER_RTT_IN_RAM
Indicate the whole application is in RAM to prevent falsly identifying the RTT Control
Block in the init segment by defining as 1.

10.4.2.2 Channel buffer configuration
SEGGER_RTT_MODE_BLOCK_IF_FIFO_FULL
SEGGER_RTT_NO_BLOCK_SKIP
SEGGER_RTT_NO_BLOCK_TRIM

10.4.2.3 Color control sequences
RTT_CTRL_RESET
Reset the text color and background color.

RTT_CTRL_TEXT_*
Set the text color to one of the following colors.
•
•
•
•
•
•
•
•
•
•

BLACK
RED
GREEN
YELLOW
BLUE
MAGENTA
CYAN
WHITE (light grey)
BRIGHT_BLACK (dark grey)
BRIGHT_RED

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•
•
•
•
•
•

BRIGHT_GREEN
BRIGHT_YELLOW
BRIGHT_BLUE
BRIGHT_MAGENTA
BRIGHT_CYAN
BRIGHT_WHITE

RTT_CTRL_BG_*
Set the background color to one of the following colors.
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•

BLACK
RED
GREEN
YELLOW
BLUE
MAGENTA
CYAN
WHITE (light grey)
BRIGHT_BLACK (dark grey)
BRIGHT_RED
BRIGHT_GREEN
BRIGHT_YELLOW
BRIGHT_BLUE
BRIGHT_MAGENTA
BRIGHT_CYAN
BRIGHT_WHITE

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10.5 Example code
/*********************************************************************
*
SEGGER MICROCONTROLLER GmbH & Co KG
*
*
Solutions for real time microcontroller applications
*
**********************************************************************
*
*
*
(c) 2014 SEGGER Microcontroller GmbH & Co KG
*
*
*
*
www.segger.com
Support: support@segger.com
*
*
*
**********************************************************************
---------------------------------------------------------------------File
: RTT.c
Purpose : Simple implementation for output via RTT.
It can be used with any IDE.
-------- END-OF-HEADER --------------------------------------------*/
#include "SEGGER_RTT.h"
static void _Delay(int period) {
int i = 100000*period;
do { ; } while (i--);
}
int main(void) {
int Cnt = 0;
SEGGER_RTT_WriteString(0, "Hello World from SEGGER!\n");
do {
SEGGER_RTT_printf("%sCounter: %s%d\n",
RTT_CTRL_TEXT_BRIGHT_WHITE,
RTT_CTRL_TEXT_BRIGHT_GREEN,
Cnt);
if (Cnt > 100) {
SEGGER_RTT_TerminalOut(1, RTT_CTRL_TEXT_BRIGHT_RED"Counter overflow!");
Cnt = 0;
}
_Delay(100);
Cnt++;
} while (1);
return 0;
}
/*************************** End of file ****************************/

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10.6 FAQ
Q:
A:

How does J-Link find the RTT buffer?
There are two ways: If the debugger (IDE) knows the address of the SEGGER RTT
Control Block, it can pass it to J-Link. This is for example done by J-Link Debugger.
If another application that is not SEGGER RTT aware is used, then J-Link searches
for the ID in the known target RAM during execution of the application in the background. This process normally takes just fractions of a second and does not delay
program execution.

Q:

I am debugging a RAM-only application. J-Link finds an RTT buffer, but I get no
output. What can I do?
In case the init section of an application is stored in RAM, J-Link migh falsely identify the block in the init section instead of the actual one in the data section.
To prevent this, set the define SEGGER_RTT_IN_RAM to 1. Now J-Link will find the
correct RTT buffer, but only after calling the first SEGGER_RTT function in the
application. A call to SEGGER_RTT_Init() at the beginning of the application is recommended.

A:

Q:
A:

Can this also be used on targets that do not have the SWO pin?
Yes, the debug interface is used. This can be JTAG or SWD (2pins only!) on most
Cortex-M devices, or even the FINE interface on some Renesas devices, just like
the Infineon SPD interface (single pin!).

Q:
A:

Can this also be used on Cortex-M0 and M0+?
Yes.

Q:

Some terminal output (printf) Solutions "crash" program execution when executed
outside of the debug environment, because they use a Software breakpoint that
triggers a hardfault without debugger or halt because SWO is not initialized. That
makes it impossible to run a Debug-build in stand-alone mode.
What about SEGGER-RTT?
SEGGER-RTT uses non-blocking mode per default, which means it does not halt
program execution if no debugger is present and J-Link is not even connected. The
application program will continue to work.

A:

Q:

I do not see any output, although the use of RTT in my application is correct. What
can I do?
In some cases J-Link cannot locate the RTT buffer in the known RAM region.
In this case the possible region or the exact address can be set manually via a JLink exec command:

A:

•
•
•

Set ranges to be searched for RTT buffer: SetRTTSearchRanges  [,  , ...] (e.g. "SetRTTSearchRanges 0x10000000 0x1000, 0x2000000 0x1000")
Set address of the RTT buffer: SetRTTAddr  (e.g. "SetRTTAddr 0x20000000")
Set address of the RTT buffer via J-Link Control Panel -> RTTerminal

Note:
J-Link exec commands can be executed in most applications, for example
in J-Link Commander via "exec ", in J-Link GDB Server via "monitor
exec " or in IAR EW via "__jlinkExecCommand("");" from a
macro file.

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Chapter 11
Device specifics

This chapter describes for which devices some special handling is necessary to use
them with J-Link.

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Device specifics

11.1 Analog Devices
J-Link has been tested with the following MCUs from Analog Devices:
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•

AD7160
ADuC7020x62
ADuC7021x32
ADuC7021x62
ADuC7022x32
ADuC7022x62
ADuC7024x62
ADuC7025x32
ADuC7025x62
ADuC7026x62
ADuC7027x62
ADuC7028x62
ADuC7030
ADuC7031
ADuC7032
ADuC7033
ADuC7034
ADuC7036
ADuC7038
ADuC7039
ADuC7060
ADuC7061
ADuC7062
ADuC7128
ADuC7129
ADuC7229x126
ADuCRF02
ADuCRF101

11.1.1 ADuC7xxx
11.1.1.1 Software reset
A special reset strategy has been implemented for Analog Devices ADuC7xxx MCUs.
This special reset strategy is a software reset. "Software reset" means basically
RESET pin is used to perform the reset, the reset is initiated by writing special function registers via software.
The software reset for Analog Devices ADuC7xxxx executes the following sequence:
•
•
•
•

The CPU is halted
A software reset sequence is downloaded to RAM.
A breakpoint at address 0 is set
The software reset sequence is executed.

It is recommended to use this reset strategy. This sequence performs a reset of CPU
and peripherals and halts the CPU before executing instructions of the user program.
It is the recommended reset sequence for Analog Devices ADuC7xxx MCUs and works
with these devices only.

This information is applicable to the following devices:
•
•
•
•
•
•
•
•

Analog
Analog
Analog
Analog
Analog
Analog
Analog
Analog

ADuC7020x62
ADuC7021x32
ADuC7021x62
ADuC7022x32
ADuC7022x62
ADuC7024x62
ADuC7025x32
ADuC7025x62

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•
•
•
•
•
•
•
•
•

Analog
Analog
Analog
Analog
Analog
Analog
Analog
Analog
Analog

ADuC7026x62
ADuC7027x62
ADuC7030
ADuC7031
ADuC7032
ADuC7033
ADuC7128
ADuC7129
ADuC7229x126

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Device specifics

11.2 ATMEL
J-Link has been tested with the following ATMEL devices:
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•

AT91SAM3A2C
AT91SAM3A4C
AT91SAM3A8C
AT91SAM3N1A
AT91SAM3N1B
AT91SAM3N1C
AT91SAM3N2A
AT91SAM3N2B
AT91SAM3N2C
AT91SAM3N4A
AT91SAM3N4B
AT91SAM3N4C
AT91SAM3S1A
AT91SAM3S1B
AT91SAM3S1C
AT91SAM3S2A
AT91SAM3S2B
AT91SAM3S2C
AT91SAM3S4A
AT91SAM3S4B
AT91SAM3S4C
AT91SAM3U1C
AT91SAM3U2C
AT91SAM3U4C
AT91SAM3U1E
AT91SAM3U2E
AT91SAM3U4E
AT91SAM3X2C
AT91SAM3X2E
AT91SAM3X2G
AT91SAM3X2H
AT91SAM3X4C
AT91SAM3X4E
AT91SAM3X4G
AT91SAM3X4H
AT91SAM3X8C
AT91SAM3X8E
AT91SAM3X8G
AT91SAM3X8H
AT91SAM7A3
AT91SAM7L64
AT91SAM7L128
AT91SAM7S16
AT91SAM7S161
AT91SAM7S32
AT91SAM7S321
AT91SAM7S64
AT91SAM7S128
AT91SAM7S256
AT91SAM7S512
AT91SAM7SE32
AT91SAM7SE256
AT91SAM7SE512
AT91SAM7X128
AT91SAM7X256
AT91SAM7X512
AT91SAM7XC128
AT91SAM7XC256

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•
•
•

AT91SAM7XC512
AT91SAM9XE128
AT91SAM9XE256

11.2.1 AT91SAM7
11.2.1.1 Reset strategy
The reset pin of the device is per default disabled. This means that the reset strategies which rely on the reset pin (low pulse on reset) do not work per default. For this
reason a special reset strategy has been made available.
It is recommended to use this reset strategy. This special reset strategy resets the
peripherals by writing to the RSTC_CR register. Resetting the peripherals puts all
peripherals in the defined reset state. This includes memory mapping register, which
means that after reset flash is mapped to address 0. It is also possible to achieve the
same effect by writing 0x4 to the RSTC_CR register located at address 0xfffffd00.

This information is applicable to the following devices:
•
•
•
•
•

AT91SAM7S (all devices)
AT91SAM7SE (all devices)
AT91SAM7X (all devices)
AT91SAM7XC (all devices)
AT91SAM7A (all devices)

11.2.1.2 Memory mapping
Either flash or RAM can be mapped to address 0. After reset flash is mapped to
address 0. In order to majlink_supported_devices.html RAM to address 0, a 1 can be
written to the RSTC_CR register. Unfortunately, this remap register is a toggle register, which switches between RAM and flash every time bit zero is written.
In order to achieve a defined mapping, there are two options:
1.
2.

Use the software reset described above.
Test if RAM is located at 0 using multiple read/write operations and testing the
results.

Clearly 1. is the easiest solution and is recommended.

This information is applicable to the following devices:
•
•
•
•
•

AT91SAM7S (all devices)
AT91SAM7SE (all devices)
AT91SAM7X (all devices)
AT91SAM7XC (all devices)
AT91SAM7A (all devices)

11.2.1.3 Recommended init sequence
In order to work with an ATMEL AT91SAM7 device, it has to be initialized. The following paragraph describes the steps of an init sequence. An example for different software tools, such as J-Link GDB Server, IAR Workbench and RDI, is given.
•
•
•
•
•
•

Set JTAG speed to 30kHz.
Reset target.
Perform peripheral reset.
Disable watchdog.
Initialize PLL.
Use full JTAG speed.

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Samples
GDB Sample
# connect to the J-Link gdb server
target remote localhost:2331
monitor flash device = AT91SAM7S256
monitor flash download = 1
monitor flash breakpoints = 1
# Set JTAG speed to 30 kHz
monitor endian little
monitor speed 30
# Reset the target
monitor reset 8
monitor sleep 10
# Perform peripheral reset
monitor long 0xFFFFFD00 = 0xA5000004
monitor sleep 10
# Disable watchdog
monitor long 0xFFFFFD44 = 0x00008000
monitor sleep 10
# Initialize PLL
monitor long 0xFFFFFC20 = 0x00000601
monitor sleep 10
monitor long 0xFFFFFC2C = 0x00480a0e
monitor sleep 10
monitor long 0xFFFFFC30 = 0x00000007
monitor sleep 10
monitor long 0xFFFFFF60 = 0x00480100
monitor sleep 100
monitor speed 12000
break main
load
continue

IAR Sample
/*******************************************************************
*
*
_Init()
*/
_Init() {
__emulatorSpeed(30000);
// Set JTAG speed to 30 kHz
__writeMemory32(0xA5000004,0xFFFFFD00,"Memory");
// Perform peripheral reset
__sleep(20000);
__writeMemory32(0x00008000,0xFFFFFD44,"Memory");
// Disable Watchdog
__sleep(20000);
__writeMemory32(0x00000601,0xFFFFFC20,"Memory");
// PLL
__sleep(20000);
__writeMemory32(0x10191c05,0xFFFFFC2C,"Memory");
// PLL
__sleep(20000);
__writeMemory32(0x00000007,0xFFFFFC30,"Memory");
// PLL
__sleep(20000);
__writeMemory32(0x002f0100,0xFFFFFF60,"Memory");
// Set 1 wait state for
__sleep(20000);
// flash (2 cycles)
__emulatorSpeed(12000000);
// Use full JTAG speed
}
/*******************************************************************
*
*
execUserReset()
*/
execUserReset() {
__message "execUserReset()";
_Init();
}
/*******************************************************************
*
*
execUserPreload()
*/
execUserPreload() {
__message "execUserPreload()";
_Init();
}

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RDI Sample
SetJTAGSpeed(30);
Reset(0, 0);
Write32(0xFFFFFD00, 0xA5000004);
Write32(0xFFFFFD44, 0x00008000);
Write32(0xFFFFFC20, 0x00000601);
Delay(200);
Write32(0xFFFFFC2C, 0x00191C05);
Delay(200);
Write32(0xFFFFFC30, 0x00000007);
Write32(0xFFFFFF60, 0x00320300);
SetJTAGSpeed(12000);

// Set JTAG speed to 30 kHz
// Perform peripheral reset
// Disable watchdog
// Set PLL
// Set PLL and divider
// Select master clock and processor clock
// Set flash wait states

11.2.2 AT91SAM9
11.2.2.1 JTAG settings
We recommend using adaptive clocking.

This information is applicable to the following devices:
•
•
•
•
•

AT91RM9200
AT91SAM9260
AT91SAM9261
AT91SAM9262
AT91SAM9263

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11.3 DSPGroup
J-Link has been tested with the following DSPGroup devices:
•

DA56KLF

Currently, there are no specifics for these devices.

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11.4 Ember
For more information, please refer to Silicon Labs on page 333.

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11.5 Energy Micro
For more information, please refer to Silicon Labs on page 333.

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11.6 Freescale
J-Link has been tested with the following Freescale devices:
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•

MAC7101
MAC7106
MAC7111
MAC7112
MAC7116
MAC7121
MAC7122
MAC7126
MAC7131
MAC7136
MAC7141
MAC7142
MK10DN512
MK10DX128
MK10DX256
MK20DN512
MK20DX128
MK20DX256
MK30DN512
MK30DX128
MK30DX256
MK40N512
MK40X128
MK40X256
MK50DN512
MK50DX256
MK50DN512
MK50DX256
MK51DX256
MK51DN512
MK51DX256
MK51DN512
MK51DN256
MK51DN512
MK52DN512
MK53DN512
MK53DX256
MK60N256
MK60N512
MK60X256

11.6.1 Kinetis family
11.6.1.1 Unlocking
If your device has been locked by setting the MCU security status to "secure", and
mass erase via debug interface is not disabled, J-Link is able to unlock your Kinetis
K40/K60 device. The device can be unlocked by using the "unlock" command in JLink Commander.
For more information regarding the MCU security status of the Kinetis devices, please
refer to the user manual of your device.

11.6.1.2 Tracing
The first silicon of the Kinetis devices did not match the data setup and hold times
which are necessary for ETM-Trace. On these devices, a low drive strength should be
configured for the trace clock pin in order to match the timing requirements.
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On later silicons, this has been corrected. This bug applies to all devices with mask
0M33Z from the 100MHz series.
The J-Link software and documentation package comes with a sample project for the
Kinetis K40 and K60 devices which is pre-configured for the TWR-40 and TWR-60 eval
boards and ETM / ETB Trace. This sample project can be found at \Samples\JLink\Projects .

11.6.1.3 Data flash support
Some devices of the Kinetis family have an additional area called FlexNVM, which can
be configured as data flash. The size of the FlexNVM to be used as data flash is configurable and needs to be configured first, before this area can be used as data flash.
The sample below shows how to configure the FlexNVM area to be used as data flash
out of the target application.
For J-Flash there are also projects that are preconfigured to setup the data flash size
of a Kinetis device. The projects can be found at $JLINK_INST_DIR$\Samples\JFlash\ProjectFiles.
One
of
these
sample
projects
is
the
MK40DX256xxx10_ConfigureDataFlash.jflash .
For more information about how configuration of the data flash works, please refer to
the appropriate user manual of the device.

Configure FlexNVM area as data flash
The follwing sample configures the data flash size of Kinetis device. It is created for a
MK40DX256xxx10 device. The sequence is almost the same for all Kinetis devices
only the lines which configure size of the data flash may be modified. In this sample
the data flash is set to max size. EEPROM size is set to 0 bytes.
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define

FSTAT
FCCOB0
FCCOB1
FCCOB2
FCCOB3
FCCOB4
FCCOB5
FCCOB6
FCCOB7
FCCOB8

(*(volatile
(*(volatile
(*(volatile
(*(volatile
(*(volatile
(*(volatile
(*(volatile
(*(volatile
(*(volatile
(*(volatile

unsigned
unsigned
unsigned
unsigned
unsigned
unsigned
unsigned
unsigned
unsigned
unsigned

char*)(0x40020000
char*)(0x40020000
char*)(0x40020000
char*)(0x40020000
char*)(0x40020000
char*)(0x40020000
char*)(0x40020000
char*)(0x40020000
char*)(0x40020000
char*)(0x40020000

+
+
+
+
+
+
+
+
+
+

0x00))
0x07))
0x06))
0x05))
0x04))
0x0B))
0x0A))
0x09))
0x08))
0x0F))

void ConfigureDataFlash(void);
*******************************************************************
*
*
ConfigureDataFlash
*
* Notes
*
Needs to be located in RAM since it performs flash operations
*
which make instruction fetching from flash temporarily not possible.
*/
void ConfigureDataFlash(void) {
unsigned char v;
//
// Read out current configuration first
//
FSTAT = 0x70;
// Clear error flags in status register
FCCOB0 = 0x03;
// Read resource
FCCOB1 = 0x80;
// Read from data flash IFR area with offset 0xFC (0x8000FC)
FCCOB2 = 0x00;
FCCOB3 = 0xFC;
FCCOB8 = 0x00;
// Select IFR area to be read
FSTAT = 0x80;
// Start command execution
while((FSTAT & 0x80) == 0); // Wait until flash controller has finished
//
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// Check current data flash & EEPROM config
//
v = FCCOB6;
// IFR offset 0xFD
if (v != 0xFF) {
// EEPROM data set size already configured?
return;
}
v = FCCOB7;
// IFR offset 0xFC
if (v != 0xFF) {
// FlexNVM partition code already configured?
return;
}
//
// Configure EEPROM size and data flash size
// via the program partition command
//
FCCOB0 = 0x80;
// Program partition
FCCOB4 = 0x3F;
// EEPROM data size code: 0 KB EEPROM
FCCOB5 = 0x00;
// FlexNVM partition code: 256 KB data flash
FSTAT = 0x80;
// Start command execution
while((FSTAT & 0x80) == 0);
// Wait until flash controller has finished
}

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11.7 Fujitsu
J-Link has been tested with the following Fujitsu devices:
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•

MB9AF102N
MB9AF102R
MB9AF104N
MB9AF104R
MB9BF104N
MB9BF104R
MB9BF105N
MB9BF105R
MB9BF106N
MB9BF106R
MB9BF304N
MB9BF304R
MB9BF305N
MB9BF305R
MB9BF306N
MB9BF306R
MB9BF404N
MB9BF404R
MB9BF405N
MB9BF405R
MB9BF406N
MB9BF406R
MB9BF504N
MB9BF504R
MB9BF505N
MB9BF505R
MB9BF506N
MB9BF506R

Currently, there are no specifics for these devices.

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11.8 Itron
J-Link has been tested with the following Itron devices:
•

TRIFECTA

Currently, there are no specifics for these devices.

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11.9 Infineon
J-Link has been tested with the following Infineon devices:
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•

UMF1110
UMF1120
UMF5110
UMF5120
XMC1100-T016F00xx
XMC1100-T038F00xx
XMC1100-T038F0xxx
XMC1201-T028F0xxx
XMC1201-T038F0xxx
XMC1202-T016X00xx
XMC1202-T028X00xx
XMC1202-T038X00xx
XMC1203-T016X0xxx
XMC1301-T016F00xx
XMC1302-T038X0xxx
XMC4100-128
XMC4104-128
XMC4104-64
XMC4200-256
XMC4400-256
XMC4400-512
XMC4402-256
XMC4500-1024
XMC4500-768
XMC4502
XMC4504

Currently, there are no specifics for these devices.

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11.10 Luminary Micro
J-Link has been tested with the following Luminary Micro devices:
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•

LM3S101
LM3S102
LM3S301
LM3S310
LM3S315
LM3S316
LM3S317
LM3S328
LM3S601
LM3S610
LM3S611
LM3S612
LM3S613
LM3S615
LM3S617
LM3S618
LM3S628
LM3S801
LM3S811
LM3S812
LM3S815
LM3S817
LM3S818
LM3S828
LM3S2110
LM3S2139
LM3S2410
LM3S2412
LM3S2432
LM3S2533
LM3S2620
LM3S2637
LM3S2651
LM3S2730
LM3S2739
LM3S2939
LM3S2948
LM3S2950
LM3S2965
LM3S6100
LM3S6110
LM3S6420
LM3S6422
LM3S6432
LM3S6610
LM3S6633
LM3S6637
LM3S6730
LM3S6938
LM3S6952
LM3S6965

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11.10.1 Unlocking LM3Sxxx devices
If your device has been "locked" accidentially (e.g. by bad application code in flash
which mis-configures the PLL) and J-Link can not identify it anymore, there is a special unlock sequence which erases the flash memory of the device, even if it cannot
be identified. This unlock sequence can be sent to the target, by using the "unlock"
command in J-Link Commander.

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11.11 NXP
J-Link has been tested with the following NXP devices:
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•

LPC1111
LPC1113
LPC1311
LPC1313
LPC1342
LPC1343
LPC1751
LPC1751
LPC1752
LPC1754
LPC1756
LPC1758
LPC1764
LPC1765
LPC1766
LPC1768
LPC2101
LPC2102
LPC2103
LPC2104
LPC2105
LPC2106
LPC2109
LPC2114
LPC2119
LPC2124
LPC2129
LPC2131
LPC2132
LPC2134
LPC2136
LPC2138
LPC2141
LPC2142
LPC2144
LPC2146
LPC2148
LPC2194
LPC2212
LPC2214
LPC2292
LPC2294
LPC2364
LPC2366
LPC2368
LPC2378
LPC2468
LPC2478
LPC2880
LPC2888
LPC2917
LPC2919
LPC2927
LPC2929
PCF87750
SJA2010
SJA2510

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11.11.1 LPC ARM7-based devices
11.11.1.1Fast GPIO bug
The values of the fast GPIO registers cannot be read directly via JTAG from a debugger. The direct access to the registers corrupts the returned values. This means that
the values in the fast GPIO registers normally cannot be checked or changed by a
debugger.

Solution / Workaround
J-Link supports command strings which can be used to read a memory area indirectly. Indirect reading means that a small code snippet will be written into RAM of
the target device, which reads and transfers the data of the specified memory area to
the debugger. Indirect reading solves the fast GPIO problem, because only direct register access corrupts the register contents.
Define a 256 byte aligned area in RAM of the LPC target device with the J-Link command map ram and define afterwards the memory area which should be read indirect
with the command map indirectread to use the indirectly reading feature of J-Link.
Note that the data in the defined RAM area is saved and will be restored after using
the RAM area.

This information is applicable to the following devices:
•
•
•
•
•
•
•

LPC2101
LPC2102
LPC2103
LPC213x/01
LPC214x (all devices)
LPC23xx (all devices)
LPC24xx (all devices)

Example
J-Link commands line options can be used for example with the C-SPY debugger of
the IAR Embedded Workbench. Open the Project options dialog and select Debugger. Select Use command line options in the Extra Options tap and enter in the
textfield --jlink_exec_command "map ram 0x40000000-0x40003fff; map indirectread 0x3fffc000-0x3fffcfff; map exclude 0x3fffd000-0x3fffffff;" as shown
in the screenshot below.

With these additional commands the values of the fast GPIO registers in the C-SPY
debugger are correct and can be used for debugging. For more information about JLink command line options refer to subchapter Command strings on page 200.
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11.11.1.2RDI
J-Link comes with a device-based RDI license for NXP LPC21xx-LPC24xx devices. This
means the J-Link RDI software can be used with LPC21xx-LPC24xx devices free of
charge. For more information about device-based licenses, please refer to License
types on page 51.

11.11.2 Reset (Cortex-M3 based devices)
For Cortex-M3 based NXP LPC devices the reset itself does not differ from the one for
other Cortex-M3 based devices: After the device has been reset, the core is halted
before any instruction is performed. For the Cortex-M3 based LPC devices this means
the CPU is halted before the bootloader which is mapped at address 0 after reset.
The user should write the memmap register after reset, to ensure that user flash is
mapped at address 0. Moreover, the user have to correct the Stack pointer (R13) and
the PC (R15) manually, after reset in order to debug the application.

11.11.3 LPC288x flash programming
In order to use the LPC288x devices in combination with the J-Link flash download
feature, the application you are trying to debug, should be linked to the original flash
@ addr 0x10400000. Otherwise it is user’s responsibility to ensure that flash is remapped to 0x0 in order to debug the application from addr 0x0.

11.11.4 LPC43xx:
All devices of the LPC43xx are dual core devices (One Cortex-M4 core and one Cortex-M0 core). For these devices, a J-Link script file is needed (exact file depends on if
the Cortex-M4 or the Cortex-M0 shall be debugged) in order to guarantee proper
functionality.
Script file can be found at $JLINK_INST_DIR$\Samples\JLink\Scripts
For more information about how to use J-Link script files, please refer to Executing JLink script files on page 199.

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11.12 OKI
J-Link has been tested with the following OKI devices:
•
•
•
•
•
•

ML67Q4002
ML67Q4003
ML67Q4050
ML67Q4051
ML67Q4060
ML67Q4061

Currently, there are no specifics for these devices.

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11.13 Renesas
J-Link has been tested with the following Renesas devices:
•
•
•
•
•
•
•
•
•
•
•
•

R5F56104
R5F56106
R5F56107
R5F56108
R5F56216
R5F56217
R5F56218
R5F562N7
R5F562N8
R5F562T6
R5F562T7
R5F562TA

Currently, there are no specifics for these devices.

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11.14 Samsung
J-Link has been tested with the following Samsung devices:
•

S3FN60D

11.14.1 S3FN60D
On the S3FN60D the watchdog may be running after reset (depends on the content
of the smart option bytes at addr. 0xC0). The watchdog keeps counting even if the
CPU is in debug mode (e.g. halted). So, please do not use the watchdog when debugging to avoid unexpected behavior of the target application. A special reset strategy
has been implemented for this device which disables the watchdog right after a reset
has been performed. We recommend to use this reset strategy when debugging a
Samsung S3FN60D device.

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11.15 Silicon Labs
J-Link has been tested with the following Silicon Labs devices:
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•

EFM32G200F16
EFM32G200F32
EFM32G200F64
EFM32G210F128
EFM32G230F32
EFM32G230F64
EFM32G230F128
EFM32G280F32
EFM32G280F64
EFM32G280F128
EFM32G290F32
EFM32G290F64
EFM32G290F128
EFM32G840F32
EFM32G840F64
EFM32G840F128
EFM32G880F32
EFM32G880F64
EFM32G880F128
EFM32G890F32
EFM32G890F64
EFM32G890F128
EFM32TG108F4
EFM32TG108F8
EFM32TG108F16
EFM32TG108F32
EFM32TG110F4
EFM32TG110F8
EFM32TG110F16
EFM32TG110F32
EFM32TG210F8
EFM32TG210F16
EFM32TG210F32
EFM32TG230F8
EFM32TG230F16
EFM32TG230F32
EFM32TG840F8
EFM32TG840F16
EFM32TG840F32
EM351
EM357

11.15.1 EFM32 series devices
11.15.1.1SWO
Usually, the SWO output frequency of a device is directly dependent on the CPU
speed. The SWO speed is calculated as:  / n. On the EFM32 series this is
not the case:
The SWO related units (ITM, TPIU, ...) are chip-internally wired to a fixed 14 MHz
clock (AUXHFRCO).
This will cause the auto-detection of J-Link to not work by default for these devices,
if the CPU is running at a different speed than AUXHFRCO. All utilities that use SWO
speed auto-detection, like the J-Link SWOViewer, need to be told that the CPU is running at 14 MHz, to make SWO speed auto-detection work, no matter what speed the
CPU is really running at.

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11.16 ST Microelectronics
J-Link has been tested with the following ST Microelectronics devices:
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•

STR710FZ1
STR710FZ2
STR711FR0
STR711FR1
STR711FR2
STR712FR0
STR712FR1
STR712FR2
STR715FR0
STR730FZ1
STR730FZ2
STR731FV0
STR731FV1
STR731FV2
STR735FZ1
STR735FZ2
STR736FV0
STR736FV1
STR736FV2
STR750FV0
STR750FV1
STR750FV2
STR751FR0
STR751FR1
STR751FR2
STR752FR0
STR752FR1
STR752FR2
STR755FR0
STR755FR1
STR755FR2
STR755FV0
STR755FV1
STR755FV2
STR911FM32
STR911FM44
STR911FW32
STR911FW44
STR912FM32
STR912FM44
STR912FW32
STR912FW44
STM32F101C6
STM32F101C8
STM32F101R6
STM32F101R8
STM32F101RB
STM32F101V8
STM32F101VB
STM32F103C6
STM32F103C8
STM32F103R6
STM32F103R8
STM32F103RB
STM32F103V8
STM32F103VB

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11.16.1 STR91x
11.16.1.1JTAG settings
These device are ARM966E-S based. We recommend to use adaptive clocking for
these devices.

11.16.1.2Unlocking
The devices have 3 TAP controllers built-in. When starting J-Link.exe, it reports 3
JTAG devices. A special tool, J-Link STR9 Commander ( JLinkSTR91x.exe) is available
to directly access the flash controller of the device. This tool can be used to erase the
flash of the controller even if a program is in flash which causes the ARM core to
stall. For more information about the J-Link STR9 Commander, please refer to J-Link
STR91x Commander (Command line tool) on page 134.
When starting the STR91x commander, a command sequence will be performed
which brings MCU into Turbo Mode.
"While enabling the Turbo Mode, a dedicated test mode signal is set and controls the
GPIOs in output. The IOs are maintained in this state until a next JTAG instruction is
sent." (ST Microelectronics)
Enabling Turbo Mode is necessary to guarantee proper function of all commands in
the STR91x Commander.

11.16.1.3Switching the boot bank
The bootbank of the STR91x devices can be switched by using the J-Link STR9 Commander which is part of the J-Link software and documentation package. For more
information about the J-Link STR9 Commander, please refer to J-Link STR91x Commander (Command line tool) on page 134.

11.16.2 STM32F10xxx
These devices are Cortex-M3 based.
All devices of this family are supported by J-Link.

11.16.2.1ETM init
The following sequence can be used to prepare STM32F10xxx devices for 4-bit ETM
tracing:
int v;
//
// DBGMCU_CR, enable trace I/O and configure pins for 4-bit trace.
//
v = *((volatile int *)(0xE0042004));
v &= ~(7 << 5); // Preserve all bits except the trace pin configuration
v |= (7 << 5); // Enable trace I/O and configure pins for 4-bit trace
*((volatile int *)(0xE0042004)) = v;

11.16.2.2 Option byte programming
J-Flash supports programming of the option bytes for STM32 devices. In order to
program the option bytes simply choose the appropriate Device, which allows option
byte programming, in the CPU settings tab (e.g. STM32F103ZE (allow opt.
bytes) ). J-Flash will allow programming a virtual 16-byte sector at address

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0x06000000 which represents the 8 option bytes and their complements. You do not
have to care about the option bytes’ complements since they are computated automatically. The following table describes the structure of the option bytes sector:
Address

0x06000000
0x06000004
0x06000008
0x0600000C

[31:24]

complement
complement
complement
complement

[23:16]

Option
Option
Option
Option

byte
byte
byte
byte

[15:8]

1
3
5
7

complement
complement
complement
complement

[7:0]

Option
Option
Option
Option

byte
byte
byte
byte

0
2
4
6

Table 11.1: Option bytes sector description

Note:
Writing a value of 0xFF inside option byte 0 will read-protect the STM32.
In order to keep the device unprotected you have to write the key value 0xA5 into
option byte 0.
Note:
The address 0x06000000 is a virtual address only. The option bytes are
originally located at
address 0x1FFFF800. The remap from 0x06000000 to
0x1FFFF800 is done automatically by J-Flash.

Example
To program the option bytes 2 and 3 with the values 0xAA and 0xBB, but leave the
device unprotected your option byte sector (at addr 0x06000000) should look like as
follows:
Address

0x06000000
0x06000004
0x06000008
0x0600000C

[31:24]

0x00
0x44
0x00
0x00

[23:16]

0xFF
0xBB
0xFF
0xFF

[15:8]

0x5A
0x55
0x00
0x00

[7:0]

0xA5
0xAA
0xFF
0xFF

Table 11.2: Option bytes programming example

For a detailed description of each option byte, please refer to ST programming manual PM0042, section "Option byte description".

11.16.2.3Securing/unsecuring the device
The user area internal flash of the STM32 devices can be protected (secured) against
read by untrusted code. The J-Flash software allows securing a STM32F10x device.
For more information about J-Flash, please refer to UM08003, J-Flash User Guide . In
order to unsecure a read-protected STM32F10x device, SEGGER offers two software
components:
•
•

J-Flash
J-Link STM32 Commander (command line utility)

For more information about J-Flash, please refer to UM08003, J-Flash User Guide . For
more information about the J-Link STM32 Commander, please refer to J-Link STM32
Unlock (Command line tool) on page 135.
Note:
memory.

Unsecuring a secured device will cause a mass-erase of the internal flash

11.16.2.4Hardware watchdog
The hardware watchdog of a STM32F10x device can be enabled by programming the
option bytes. If the hardware watchdog is enabled the device is reset periodically if
the watchdog timer is not refreshed and reaches 0. If the hardware watchdog is
enabled by an application which is located in flash and which does not refresh the
watchdog timer, the device can not be debugged anymore.

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Disabling the hardware watchdog
In order to disable the hardware watchdog the option bytes have to be re-programmed. SEGGER offers a free command line tool which reprograms the option
bytes in order to disable the hardware watchdog. For more information about the
STM32 commander, please refer to J-Link STM32 Unlock (Command line tool) on
page 135.

11.16.2.5Debugging with software watchdog enabled
If the device shall be debugged with one of the software watchdogs (independed
watchdog / window watchdog) enabled, there is an additional init step necessary to
make the watchdog counter stop when the CPU is halted by the debugger. This is
configured in the DBGMCU_CR register. The following sequence can be used to enable
debugging with software watchdogs enabled:
//
// Configure both watchdog timers to be halted if the CPU is halted by the debugger
//
*((volatile int *)(0xE0042004)) |= (1 << 8) | (1 << 9);

11.16.3 STM32F2xxx
These devices are Cortex-M3 based.
All devices of this family are supported by J-Link.

11.16.3.1ETM init
The following sequence can be used to prepare STM32F2xxx devices for 4-bit ETM
tracing:
int v;
//
// Enable GPIOE clock
//
*((volatile int *)(0x40023830)) = 0x00000010;
//
// Assign trace pins to alternate function in order
// to make them usable as trace pins
// PE2: Trace clock
// PE3: TRACE_D0
// PE4: TRACE_D1
// PE5: TRACE_D2
// PE6: TRACE_D3
//
*((volatile int *)(0x40021000)) = 0x00002AA0;
//
// DBGMCU_CR, enable trace I/O and configure pins for 4-bit trace.
//
v = *((volatile int *)(0xE0042004));
v &= ~(7 << 5); // Preserve all bits except the trace pin configuration
v |= (7 << 5); // Enable trace I/O and configure pins for 4-bit trace
*((volatile int *)(0xE0042004)) = v;

11.16.3.2Debugging with software watchdog enabled
If the device shall be debugged with one of the software watchdogs (independed
watchdog / window watchdog) enabled, there is an additional init step necessary to
make the watchdog counter stop when the CPU is halted by the debugger. This is
configured in the DBGMCU_APB1_FZ register. The following sequence can be used to
enable debugging with software watchdogs enabled:
//
// Configure both watchdog timers to be halted if the CPU is halted by the debugger
//
*((volatile int *)(0xE0042008)) |= (1 << 11) | (1 << 12);

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11.16.4 STM32F4xxx
These devices are Cortex-M4 based.
All devices of this family are supported by J-Link.

11.16.4.1ETM init
The following sequence can be used to prepare STM32F4xxx devices for 4-bit ETM
tracing:
int v;
//
// Enable GPIOE clock
//
*((volatile int *)(0x40023830)) = 0x00000010;
//
// Assign trace pins to alternate function in order
// to make them usable as trace pins
// PE2: Trace clock
// PE3: TRACE_D0
// PE4: TRACE_D1
// PE5: TRACE_D2
// PE6: TRACE_D3
//
*((volatile int *)(0x40021000)) = 0x00002AA0;
//
// DBGMCU_CR, enable trace I/O and configure pins for 4-bit trace.
//
v = *((volatile int *)(0xE0042004));
v &= ~(7 << 5); // Preserve all bits except the trace pin configuration
v |= (7 << 5); // Enable trace I/O and configure pins for 4-bit trace
*((volatile int *)(0xE0042004)) = v;

11.16.4.2Debugging with software watchdog enabled
If the device shall be debugged with one of the software watchdogs (independed
watchdog / window watchdog) enabled, there is an additional init step necessary to
make the watchdog counter stop when the CPU is halted by the debugger. This is
configured in the DBGMCU_APB1_FZ register. The following sequence can be used to
enable debugging with software watchdogs enabled:
//
// Configure both watchdog timers to be halted if the CPU is halted by the debugger
//
*((volatile int *)(0xE0042008)) |= (1 << 11) | (1 << 12);

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11.17 Texas Instruments
J-Link has been tested with the following Texas Instruments devices:
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•

AM3352
AM3354
AM3356
AM3357
AM3358
AM3359
OMAP3530
OMAP3550
OMAP4430
OMAP-L138
TMS470M
TMS470R1A64
TMS470R1A128
TMS470R1A256
TMS470R1A288
TMS470R1A384
TMS470R1B512
TMS470R1B768
TMS470R1B1M
TMS470R1VF288
TMS470R1VF688
TMS470R1VF689

11.17.1 AM335x
The AM335x series devices need some special handling which requires the correct
device is selected in the J-Link DLL. When used out of a debugger, this is usually
done automatically (see Software reset on page 310). For J-Link Commander & JLink GDBServer this needs to be done manually.

11.17.1.1Selecting the device in the IDE
When using J-Link in an IDE, there is usually a way to directly select the device in the
IDE, since it usually also needs this information for peripheral register view etc. The
selected device is then usually automatically passed to the J-Link DLL.
The screenshot below is an example for a device selection inside emIDE (http://
www.emide.org).

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11.17.1.2Selecting the device when using GDBServer
When using the J-Link GDBServer, the device needs to be known before GDB connects to the GDBServer since GDBServer connects to the device as soon as it is
started. So selecting the device via monitor command is too late. In order to select
the device before GDBServer connects to it, simply start it with the following command line:
-device 
Example: JLinkGDBServer -device AM3359

11.17.1.3Selecting the device when using J-Link Commander
For J-Link Commander, type:
device 

Then J-Link Commander will perform a reconnect with the device name selected
before.

11.17.1.4Known values for 
For a list of all supported devices, please refer to http://www.segger.com/
jlink_supported_devices.html

11.17.1.5Required J-Link hardware version
The special handling for the AM335x cannot be supported by some older hardware
versions of J-Link, so the device cannot be used with these versions.
The following hardware versions come with AM335x support:
•
•
•
•

J-Link V8 or later
J-Link PRO V3 or later
J-Link ULTRA V4 or later
Flasher ARM V4 or later

11.17.2 AM35xx / AM37xx
Script is not needed. Refer to AM335x special handling. Same needs to be done for
AM35xx / AM37xx.

11.17.3 OMAP4430
Script is not needed. Refer to AM335x special handling. Same needs to be done for
AM35xx / AM37xx.

11.17.4 OMAP-L138
Needs a J-Link script file to guarantee proper functionality.
J-Link script file can be found at $JLINK_INST_DIR$\Samples\JLink\Scripts.
For more information about how to use J-Link script files, please refer to Executing JLink script files on page 199.

11.17.5 TMS470M
Needs a J-Link script file to guarantee proper functionality.
J-Link script file can be found at $JLINK_INST_DIR$\Samples\JLink\Scripts
For more information about how to use J-Link script files, please refer to Executing JLink script files on page 199.

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11.17.6 OMAP3530
Needs a J-Link script file to guarantee proper functionality.
J-Link script file can be found at $JLINK_INST_DIR$\Samples\JLink\Scripts
For more information about how to use J-Link script files, please refer to Executing JLink script files on page 199.

11.17.7 OMAP3550
Needs a J-Link script file to guarantee proper functionality.
J-Link script file can be found at $JLINK_INST_DIR$\Samples\JLink\Scripts
For more information about how to use J-Link script files, please refer to Executing JLink script files on page 199.

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11.18 Toshiba
J-Link has been tested with the following Toshiba devices:
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•

TMPM321F10FG
TMPM322F10FG
TMPM323F10FG
TMPM324F10FG
TMPM330FDFG
TMPM330FWFG
TMPM330FYFG
TMPM332FWUG
TMPM333FDFG
TMPM333FWFG
TMPM333FYFG
TMPM341FDXBG
TMPM341FYXBG
TMPM360F20FG
TMPM361F10FG
TMPM362F10FG
TMPM363F10FG
TMPM364F10FG
TMPM366FDFG
TMPM366FWFG
TMPM366FYFG
TMPM370FYDFG
TMPM370FYFG
TMPM372FWUG
TMPM373FWDUG
TMPM374FWUG
TMPM380FWDFG
TMPM380FWFG
TMPM380FYDFG
TMPM380FYFG
TMPM382FSFG
TMPM382FWFG
TMPM395FWXBG

Currently, there are no specifics for these devices.

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Chapter 12
Target interfaces and adapters

This chapter gives an overview about J-Link / J-Trace specific hardware details, such
as the pinouts and available adapters.

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12.1 20-pin J-Link connector
12.1.1 Pinout for JTAG
J-Link and J-Trace have a JTAG connector compatible to ARM’s Multi-ICE. The JTAG connector is a 20
way Insulation Displacement Connector (IDC) keyed
box header (2.54mm male) that mates with IDC
sockets mounted on a ribbon cable.
*On later J-Link products like the J-link ULTRA,
these pins are reserved for firmware extension purposes. They can be left open or connected to GND in
normal debug environment. They are not essential
for JTAG/SWD in general.

V T re f

1

2

NC

nTRST
TDI

3
5

4
6

GND
GND

TM S
TCK

7
9

8
GND
10 GN D
12 GN D

RTCK

11

TDO
RESET

13
15

DBGRQ
5 V - S u p p ly

17
19

14 GN D*
16 GN D*
18 GN D*
20 GN D*

The following table lists the J-Link / J-Trace JTAG pinout.
PIN

SIGNAL

TYPE

Description

1

VTref

Input

This is the target reference voltage. It is used to check if
the target has power, to create the logic-level reference for
the input comparators and to control the output logic levels
to the target. It is normally fed from Vdd of the target board
and must not have a series resistor.

2

Not connected

NC

This pin is not connected in J-Link.

3

nTRST

Output

5

TDI

Output

7

TMS

Output

9

TCK

Output

11

RTCK

Input

13

TDO

Input

JTAG Reset. Output from J-Link to the Reset signal of the
target JTAG port. Typically connected to nTRST of the target
CPU. This pin is normally pulled HIGH on the target to avoid
unintentional resets when there is no connection.
JTAG data input of target CPU. It is recommended that this
pin is pulled to a defined state on the target board. Typically
connected to TDI of the target CPU.
JTAG mode set input of target CPU. This pin should be
pulled up on the target. Typically connected to TMS of the
target CPU.
JTAG clock signal to target CPU. It is recommended that this
pin is pulled to a defined state of the target board. Typically
connected to TCK of the target CPU.
Return test clock signal from the target. Some targets must
synchronize the JTAG inputs to internal clocks. To assist in
meeting this requirement, you can use a returned, and
retimed, TCK to dynamically control the TCK rate. J-Link
supports adaptive clocking, which waits for TCK changes to
be echoed correctly before making further changes. Connect to RTCK if available, otherwise to GND.
JTAG data output from target CPU. Typically connected to
TDO of the target CPU.

Table 12.1: J-Link / J-Trace pinout

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PIN

SIGNAL

15

RESET

17

DBGRQ

19

5V-Supply

TYPE

Description

Target CPU reset signal. Typically connected to the RESET
pin of the target CPU, which is typically called "nRST",
"nRESET" or "RESET".
This pin is not connected in J-Link. It is reserved for compatibility with other equipment to be used as a debug
NC
request signal to the target system. Typically connected to
DBGRQ if available, otherwise left open.
This pin can be used to supply power to the target hardware. Older J-Links may not be able to supply power on this
Output pin. For more information about how to enable/disable the
power supply, please refer to Target power supply on
page 346.

I/O

Table 12.1: J-Link / J-Trace pinout

Pins 4, 6, 8, 10, 12, 14, 16, 18, 20 are GND pins connected to GND in J-Link. They
should also be connected to GND in the target system.

12.1.1.1 Target board design
We strongly advise following the recommendations given by the chip manufacturer.
These recommendations are normally in line with the recommendations given in the
table Pinout for JTAG on page 344. In case of doubt you should follow the recommendations given by the semiconductor manufacturer.
You may take any female header following the specifications of DIN 41651.
For example:
Harting
Molex
Tyco Electronics

J-Link / J-Trace (UM08001)

part-no. 09185206803
part-no. 90635-1202
part-no. 2-215882-0

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Typical target connection for JTAG
Target board

JTAG connector
5V supply

Voltage
Regulator

19

1

1

3*

3

nTRST

TDI

5

5

TDI

TMS

7

7

TMS

TCK

9

9

TCK

VTref
nTRST

J-Link

19**

11*

11

RTCK

TDO

13

13

TDO

RESET

15

15

nRST

GND

20

20

RTCK

VCC

VCC

CPU

GND

* NTRST and RTCK may not be available on some CPUs.
** Optional to supply the target board from J-Link.

12.1.1.2 Pull-up/pull-down resistors
Unless otherwise specified by developer’s manual, pull-ups/pull-downs are recommended to 100 kOhms.

12.1.1.3 Target power supply
Pin 19 of the connector can be used to supply power to the target hardware. Supply
voltage is 5V, max. current is 300mA. The output current is monitored and protected
against overload and short-circuit. Power can be controlled via the J-Link commander. The following commands are available to control power:
Command
power
power
power
power

on
off
on perm
off perm

Explanation

Switch target power on
Switch target power off
Set target power supply default to "on"
Set target power supply default to "off"

Table 12.2: Command List

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12.1.2 Pinout for SWD
The J-Link and J-Trace JTAG connector is also compatible to ARM’s Serial Wire Debug (SWD).
*On later J-Link products like the J-link ULTRA,
these pins are reserved for firmware extension purposes. They can be left open or connected to GND in
normal debug environment. They are not essential
for JTAG/SWD in general.
The following table lists the J-Link / J-Trace SWD
pinout.
PIN

SIGNAL

TYPE

VTref

1

2

NC

Not used
Not used

3
5

4
6

GND
GND

SWDIO
SWCLK

7
9

8 GND
10 GND
12 GND

Not used

11

SWO
RESET

13
15

Not used
5V-Supply

17
19

14 GND*
16 GND*
18 GND*
20 GND*

Description

1

VTref

Input

This is the target reference voltage. It is used to check if
the target has power, to create the logic-level reference for
the input comparators and to control the output logic levels
to the target. It is normally fed from Vdd of the target board
and must not have a series resistor.

2

Not connected

NC

This pin is not connected in J-Link.

3

5
7

9

11
13
15
17

19

This pin is not used by J-Link. If the device may also be
accessed via JTAG, this pin may be connected to nTRST,
otherwise leave open.
This pin is not used by J-Link. If the device may also be
Not used NC
accessed via JTAG, this pin may be connected to TDI, otherwise leave open.
Single bi-directional data pin. A pull-up resistor is required.
SWDIO
I/O
ARM recommends 100 kOhms.
Clock signal to target CPU.
It is recommended that this pin is pulled to a defined state
SWCLK
Output
on the target board. Typically connected to TCK of target
CPU.
This pin is not used by J-Link when operating in SWD mode.
Not used NC
If the device may also be accessed via JTAG, this pin may
be connected to RTCK, otherwise leave open.
Serial Wire Output trace port. (Optional, not required for
SWO
Input
SWD communication.)
Target CPU reset signal. Typically connected to the RESET
RESET
I/O
pin of the target CPU, which is typically called "nRST",
"nRESET" or "RESET".
Not used NC
This pin is not connected in J-Link.
This pin can be used to supply power to the target hardware. Older J-Links may not be able to supply power on this
5V-SupOutput pin. For more information about how to enable/disable the
ply
power supply, please refer to Target power supply on
page 348.
Not Used NC

Table 12.3: J-Link / J-Trace SWD pinout

Pins 4, 6, 8, 10, 12, 14, 16, 18, 20 are GND pins connected to GND in J-Link. They
should also be connected to GND in the target system.

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12.1.2.1 Target board design
We strongly advise following the recommendations given by the chip manufacturer.
These recommendations are normally in line with the recommendations given in the
table Pinout for SWD on page 347. In case of doubt you should follow the recommendations given by the semiconductor manufacturer.

Typical target connection for SWD
Target board

JTAG connector
5V supply

J-Link

19*

Voltage
Regulator

19

1

1

SWDIO

7

7

SWCLK

9

9

SWO

13

13

SWO

RESET

15

15

nRST

100 k

VTref

SWDIO
SWCLK

VCC

VCC

CPU
GND

GND

20

20

* Optional to supply the target board from J-Link.

12.1.2.2 Pull-up/pull-down resistors
A pull-up resistor is required on SWDIO on the target board. ARM recommends 100
kOhms.
In case of doubt you should follow the recommendations given by the semiconductor
manufacturer.

12.1.2.3 Target power supply
Pin 19 of the connector can be used to supply power to the target hardware. Supply
voltage is 5V, max. current is 300mA. The output current is monitored and protected
against overload and short-circuit.
Power can be controlled via the J-Link commander. The following commands are
available to control power:
Command
power
power
power
power

on
off
on perm
off perm

Explanation

Switch target power on
Switch target power off
Set target power supply default to "on"
Set target power supply default to "off"

Table 12.4: Command List

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12.1.3 Pinout for SWD + Virtual COM Port (VCOM)
The J-Link and J-Trace JTAG connector is also
compatible to ARM’s Serial Wire Debug (SWD).
*On later J-Link products like the J-link ULTRA,
these pins are reserved for firmware extension
purposes. They can be left open or connected to
GND in normal debug environment. They are not
essential for JTAG/SWD in general.
The following table lists the J-Link / J-Trace SWD
pinout.
PIN

SIGNAL

TYPE

VTref

1

2

NC

Not used
J-Link Tx

3
5

4
6

GND
GND

SWDIO
SWCLK

7
9

8 GND
10 GND
12 GND

Not used

11

SWO
RESET

13
15

J-Link Rx
17
5V-Supply 19

14 GND*
16 GND*
18 GND*
20 GND*

Description

1

VTref

Input

This is the target reference voltage. It is used to check if
the target has power, to create the logic-level reference for
the input comparators and to control the output logic levels
to the target. It is normally fed from Vdd of the target board
and must not have a series resistor.

2

Not connected

NC

This pin is not connected in J-Link.

3

5

7

9

11
13
15

17

19

This pin is not used by J-Link. If the device may also be
accessed via JTAG, this pin may be connected to nTRST,
otherwise leave open.
This pin is used as VCOM Tx (out on J-Link side) in case
VCOM functionality of J-Link is enabled. For further informaJ-Link Tx Output
tion about VCOM, please refer to Virtual COM Port (VCOM)
on page 209.
Single bi-directional data pin. A pull-up resistor is required.
SWDIO
I/O
ARM recommends 100 kOhms.
Clock signal to target CPU.
It is recommended that this pin is pulled to a defined state
SWCLK
Output
on the target board. Typically connected to TCK of target
CPU.
This pin is not used by J-Link when operating in SWD mode.
Not used NC
If the device may also be accessed via JTAG, this pin may
be connected to RTCK, otherwise leave open.
Serial Wire Output trace port. (Optional, not required for
SWO
Input
SWD communication.)
Target CPU reset signal. Typically connected to the RESET
RESET
I/O
pin of the target CPU, which is typically called "nRST",
"nRESET" or "RESET".
This pin is used as VCOM Rx (in on J-Link side) in case
J-Link Rx input
VCOM functionality of J-Link is enabled. For further information, please refer to Virtual COM Port (VCOM) on page 209.
This pin can be used to supply power to the target hardware. Older J-Links may not be able to supply power on this
5V-SupOutput pin. For more information about how to enable/disable the
ply
power supply, please refer to Target power supply on
page 348.
Not Used NC

Table 12.5: J-Link / J-Trace SWD pinout

Pins 4, 6, 8, 10, 12, 14, 16, 18, 20 are GND pins connected to GND in J-Link. They
should also be connected to GND in the target system.

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12.1.4 Pinout for SPI
*On later J-Link products like the J-link ULTRA,
these pins are reserved for firmware extension purposes. They can be left open or connected to GND
in normal debug environment.

The following table lists the pinout for the SPI interface on J-Link.
PIN

1

2
3

SIGNAL

VTref

Not connected
Not connected

5

DI

7
9

nCS
CLK
Not connected

11

TYPE

VTref

1

2

NC

NC
DI

3
5

4
6

GND
GND

nCS
CLK

7
9

8 GND
10 GND
12 GND

NC

11

DO
nRESET

13
15

NC
17
5V-Supply 19

14 GND*
16 GND*
18 GND*
20 GND*

Description

Input

This is the target reference voltage. It is used to check if
the target has power, to create the logic-level reference for
the input comparators and to control the output logic levels
to the target. It is normally fed from Vdd of the target board
and must not have a series resistor.

NC

Leave open on target side

NC

Leave open on target side

Data-input of target SPI. Output of J-Link, used to transmit
data to the target SPI.
Output Chip-select of target SPI (active LOW).
Output SPI clock signal.
Output

NC

Leave open on target side
Data-out of target SPI. Input of J-Link, used to receive data
from the target SPI.
Target CPU reset signal. Typically connected to the RESET
pin of the target CPU, which is typically called "nRST",
"nRESET" or "RESET".

13

DO

Input

15

RESET

I/O

17

Not connected

NC

5V-Supply

This pin can be used to supply power to the target hardware. Older J-Links may not be able to supply power on this
Output pin. For more information about how to enable/disable the
power supply, please refer to Target power supply on
page 346.

19

Leave open on target side

Table 12.6: J-Link / J-Trace pinout

Pins 4, 6, 8, 10, 12 are GND pins connected to GND in J-Link. They should also be
connected to GND in the target system.

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12.2 38-pin Mictor JTAG and Trace connector
J-Trace provides a JTAG+Trace connector. This connector is a 38-pin mictor plug. It
connects to the target via a 1-1 cable.
The connector on the target board should be "TYCO type 5767054-1" or a compatible
receptacle. J-Trace supports 4, 8, and 16-bit data port widths with the high density
target connector described below.

Target board trace connector

38 37

Target
system
Pin 1
chamfer

2 1

J-Trace can capture the state of signals PIPESTAT[2:0], TRACESYNC and
TRACEPKT[n:0] at each rising edge of each TRACECLK or on each alternate rising or
falling edge.

12.2.1 Connecting the target board
J-Trace connects to the target board via a 38-pin trace cable. This cable has a receptacle on the one side, and a plug on the other side. Alternatively J-Trace can be connected with a 20-pin JTAG cable.

Warning: Never connect trace cable and JTAG cable at the same time because
this may harm your J-Trace and/or your target.

J-Trace
JTAG
+
Trace

J-Trace

ARM

Target board

J-Link / J-Trace (UM08001)

ARM

Target board
JTAG
connector

Target board
Trace
connector

Target board

JTAG

JTAG cable

Target board
Trace
connector

Trace cable

Target board
Trace
connector

JTAG
+
Trace

JTAG cable

Target board
JTAG
connector

JTAG

Trace cable

JTAG

JTAG
+
Trace

J-Trace

ARM

Target board
JTAG
connector

Target board

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12.2.2 Pinout
The following table lists the JTAG+Trace connector pinout. It is compatible to the
"Trace Port Physical Interface" described in [ETM], 8.2.2 "Single target connector
pinout".
PIN

SIGNAL

1
2
3
4
5
6
7

NC
NC
NC
NC
GND
TRACECLK
DBGRQ

8

DBGACK

9

RESET

10

EXTTRIG

11

TDO

12

VTRef

13

RTCK

14

VSupply

15

TCK

16

Trace signal 12

17

TMS

18

Trace signal 11

19

TDI

20

Trace signal 10

21

nTRST

Description

Not connected.
Not connected.
Not connected.
Not connected.
Signal ground.
Clocks trace data on rising edge or both edges.
Debug request.
Debug acknowledge from the test chip, high when in
debug state.
Open-collector output from the run control to the target
system reset.
Optional external trigger signal to the Embedded trace
Macrocell (ETM). Not used. Leave open on target system.
Test data output from target JTAG port.
Signal level reference. It is normally fed from Vdd of the
target board and must not have a series resistor.
Return test clock from the target JTAG port.
Supply voltage. It is normally fed from Vdd of the target
board and must not have a series resistor.
Test clock to the run control unit from the JTAG port.
Trace signal. For more information, please refer to
Assignment of trace information pins between ETM architecture versions on page 354.
Test mode select from run control to the JTAG port.
Trace signal. For more information, please refer to
Assignment of trace information pins between ETM architecture versions on page 354.
Test data input from run control to the JTAG port.
Trace signal. For more information, please refer to
Assignment of trace information pins between ETM architecture versions on page 354.
Active-low JTAG reset.

Table 12.7: JTAG+Trace connector pinout

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PIN

22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38

SIGNAL

Trace
Trace
Trace
Trace
Trace
Trace
Trace
Trace
Trace
Trace
Trace
Trace
Trace
Trace
Trace
Trace
Trace

signal
signal
signal
signal
signal
signal
signal
signal
signal
signal
signal
signal
signal
signal
signal
signal
signal

9
20
8
19
7
18
6
17
5
16
4
15
3
14
2
13
1

Description

Trace signals. For more information, please refer to
Assignment of trace information pins between ETM architecture versions on page 354.

Table 12.7: JTAG+Trace connector pinout

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12.2.3 Assignment of trace information pins between ETM
architecture versions
The following table show different names for the trace signals depending on the ETM
architecture version.
Trace signal

Trace
Trace
Trace
Trace
Trace
Trace
Trace
Trace
Trace
Trace
Trace
Trace
Trace
Trace
Trace
Trace
Trace
Trace
Trace
Trace

signal
signal
signal
signal
signal
signal
signal
signal
signal
signal
signal
signal
signal
signal
signal
signal
signal
signal
signal
signal

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20

ETMv1

PIPESTAT[0]
PIPESTAT[1]
PIPESTAT[2]
TRACESYNC
TRACEPKT[0]
TRACEPKT[1]
TRACEPKT[2]
TRACEPKT[3]
TRACEPKT[4]
TRACEPKT[5]
TRACEPKT[6]
TRACEPKT[7]
TRACEPKT[8]
TRACEPKT[9]
TRACEPKT[10]
TRACEPKT[11]
TRACEPKT[12]
TRACEPKT[13]
TRACEPKT[14]
TRACEPKT[15]

ETMv2

PIPESTAT[0]
PIPESTAT[1]
PIPESTAT[2]
PIPESTAT[3]
TRACEPKT[0]
TRACEPKT[1]
TRACEPKT[2]
TRACEPKT[3]
TRACEPKT[4]
TRACEPKT[5]
TRACEPKT[6]
TRACEPKT[7]
TRACEPKT[8]
TRACEPKT[9]
TRACEPKT[10]
TRACEPKT[11]
TRACEPKT[12]
TRACEPKT[13]
TRACEPKT[14]
TRACEPKT[15]

ETMv3

TRACEDATA[0]
TRACECTL
Logic 1
Logic 0
Logic 0
TRACEDATA[1]
TRACEDATA[2]
TRACEDATA[3]
TRACEDATA[4]
TRACEDATA[5]
TRACEDATA[6]
TRACEDATA[7]
TRACEDATA[8]
TRACEDATA[9]
TRACEDATA[10]
TRACEDATA[11]
TRACEDATA[12]
TRACEDATA[13]
TRACEDATA[14]
TRACEDATA[15]

Table 12.8: Assignment of trace information pins between ETM architecture versions

12.2.4 Trace signals
Data transfer is synchronized by TRACECLK.

12.2.4.1 Signal levels
The maximum capacitance presented by J-Trace at the trace port connector, including
the connector and interfacing logic, is less than 6pF. The trace port lines have a
matched impedance of 50.
The J-Trace unit will operate with a target board that has a supply voltage range of
3.0V-3.6V.

12.2.4.2 Clock frequency
For capturing trace port signals synchronous to TRACECLK, J-Trace supports a
TRACECLK frequency of up to 200MHz. The following table shows the TRACECLK frequencies and the setup and hold timing of the trace signals with respect to TRACECLK.
Parameter

Tperiod
Fmax
Tch
Tcl
Tsh

Min.

5ns
1MHz
2.5ns
2.5ns
2.5ns

Max.

1000ns
200MHz
-

Explanation

Clock period
Maximum trace frequency
High pulse width
Low pulse width
Data setup high

Table 12.9: Clock frequency

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Parameter

Thh
Tsl
Thl

Min.

1.5ns
2.5ns
1.5ns

Max.

-

Explanation

Data hold high
Data setup low
Data hold low

Table 12.9: Clock frequency

The diagram below shows the TRACECLK frequencies and the setup and hold timing
of the trace signals with respect to TRACECLK.
Tperiod

Full
TRACECLK

Tch

Tcl

DATA
Tsh

Thh

Tsl

Thl

Half-rate
TRACECLK

Note:
J-Trace supports half-rate clocking mode. Data is output on each edge of
the TRACECLK signal and TRACECLK (max) <= 100MHz. For half-rate clocking, the
setup and hold times at the JTAG+Trace connector must be observed.

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12.3 19-pin JTAG/SWD and Trace connector
J-Trace provides a JTAG/SWD+Trace connector. This
connector is a 19-pin connector. It connects to the
target via an 1-1 cable.

VTref

1

2

SWDIO/TMS

GND
GND

3
5

4
6

SWCLK/TCK
SWO/TDO

--NC

7
9

8 TDI
10 nRESET

5V-Supply

11

12 TRACECLK

5V-Supply
GND

13
15

14 TRACEDATA[0]
16 TRACEDATA[1]

GND
GND

17
19

18 TRACEDATA[2]
20 TRACEDATA[3]

The following table lists the J-Link / J-Trace SWD pinout.
PIN

SIGNAL

TYPE

1

VTref

Input

2

SWDIO/
TMS

I/O /
output

4

SWCLK/TCK Output

6

SWO/TDO

Input

---

---

---

8

TDI

Output

9

NC

NC

10

nRESET

I/O

11

5V-Supply

Output

12

TRACECLK

Input

13

5V-Supply

Output

14

TRACEDATA[0]

Input

Description

This is the target reference voltage. It is used to check if
the target has power, to create the logic-level reference
for the input comparators and to control the output logic
levels to the target. It is normally fed from Vdd of the
target board and must not have a series resistor.
SWDIO: (Single) bi-directional data pin.
JTAG mode set input of target CPU. This pin should be
pulled up on the target. Typically connected to TMS of the
target CPU.
SWCLK: Clock signal to target CPU. It is recommended
that this pin is pulled to a defined state of the target
board. Typically connected to TCK of target CPU.
JTAG clock signal to target CPU.
JTAG data output from target CPU. Typically connected to
TDO of the target CPU.
When using SWD, this pin is used as Serial Wire Output
trace port. (Optional, not required for SWD communication)
This pin (normally pin 7) is not existent on the 19-pin
JTAG/SWD and Trace connector.
JTAG data input of target CPU. It is recommended that
this pin is pulled to a defined state on the target board.
Typically connected to TDI of the target CPU. For CPUs
which do not provide TDI (SWD-only devices), this pin is
not used. J-Link will ignore the signal on this pin when
using SWD.
Not connected inside J-Link. Leave open on target hardware.
Target CPU reset signal. Typically connected to the RESET
pin of the target CPU, which is typically called "nRST",
"nRESET" or "RESET".
This pin can be used to supply power to the target hardware. For more information about how to enable/disable
the power supply, please refer to Target power supply on
page 357.
Input trace clock. Trace clock = 1/2 CPU clock.
This pin can be used to supply power to the target hardware. For more information about how to enable/disable
the power supply, please refer to Target power supply on
page 357.
Input Trace data pin 0.

Table 12.10: 19-pin JTAG/SWD and Trace pinout

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PIN

16
18
20

SIGNAL

TRACEDATA[1]
TRACEDATA[2]
TRACEDATA[3]

TYPE

Description

Input

Input Trace data pin 0.

Input

Input Trace data pin 0.

Input

Input Trace data pin 0.

Table 12.10: 19-pin JTAG/SWD and Trace pinout

Pins 3, 5, 15, 17, 19 are GND pins connected to GND in J-Trace CM3. They should
also be connected to GND in the target system.

12.3.1 Target power supply
Pins 11 and 13 of the connector can be used to supply power to the target hardware.
Supply voltage is 5V, max. current is 300mA. The output current is monitored and
protected against overload and short-circuit.
Power can be controlled via the J-Link commander. The following commands are
available to control power:
Command
power
power
power
power

on
off
on perm
off perm

Explanation

Switch target power on
Switch target power off
Set target power supply default to "on"
Set target power supply default to "off"

Table 12.11: Command List

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12.4 9-pin JTAG/SWD connector
Some target boards only provide a 9-pin JTAG/
SWD connector for Cortex-M. For these devices
SEGGER provides a 20-pin -> 9-pin Cortex-M
adapter.

VTref

1

2

SWDIO / TMS

GND
GND

3
5

4
6

SWCLK / TCK
SWO / TDO

--NC

7
9

8 TDI
10 nRESET

The following table lists the output of the 9-pin Cortex-M connector.
PIN

1

2

4

6

---

8

9

SIGNAL

TYPE

Description

This is the target reference voltage. It is used to check if
the target has power, to create the logic-level reference
VTref
Input for the input comparators and to control the output logic
levels to the target. It is normally fed from Vdd of the
target board and must not have a series resistor.
SWDIO: (Single) bi-directional data pin.
SWDIO/
I/O /
JTAG mode set input of target CPU. This pin should be
TMS
output pulled up on the target. Typically connected to TMS of the
target CPU.
SWCLK: Clock signal to target CPU. It is recommended
that this pin is pulled to a defined state of the target
SWCLK/TCK Output
board. Typically connected to TCK of target CPU.
JTAG clock signal to target CPU.
When using SWD, this pin is used as Serial Wire Output
trace port (optional, not required for SWD communicaSWO/TDO
Input tion).
JTAG data output from target CPU. Typically connected to
TDO of the target CPU.
This pin (normally pin 7) is not existent on the 19-pin
----JTAG/SWD and Trace connector.
JTAG data input of target CPU.- It is recommended that
this pin is pulled to a defined state on the target board.
Typically connected to TDI of the target CPU. For CPUs
TDI
Output
which do not provide TDI (SWD-only devices), this pin is
not used. J-Link will ignore the signal on this pin when
using SWD.
Not connected inside J-Link. Leave open on target hardNC
NC
ware.

Table 12.12: 9-pin JTAG/SWD pinout

Pins 3 and 5 are GND pins connected to GND on the Cortex-M adapter. They should
also be connected to GND in the target system.

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12.5 Adapters
There are various adapters available for J-Link as for example the JTAG isolator, the
J-Link RX adapter or the J-Link Cortex-M adapter.
For more information about the different adapters, please refer to
http://www.segger.com/jlink-adapters.html.

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Chapter 13
Background information

This chapter provides background information about JTAG and ARM. The ARM7 and
ARM9 architecture is based on Reduced Instruction Set Computer (RISC) principles.
The instruction set and the related decode mechanism are greatly simplified compared with microprogrammed Complex Instruction Set Computer (CISC).

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CHAPTER 13

Background information

13.1 JTAG
JTAG is the acronym for Joint Test Action Group. In the scope of this document,
"the JTAG standard" means compliance with IEEE Standard 1149.1-2001.

13.1.1 Test access port (TAP)
JTAG defines a TAP (Test access port). The TAP is a general-purpose port that can
provide access to many test support functions built into a component. It is composed
as a minimum of the three input connections (TDI, TCK, TMS) and one output connection (TDO). An optional fourth input connection (nTRST) provides for asynchronous initialization of the test logic.
PIN

Type

Explanation

TCK

Input

The test clock input (TCK) provides the clock for the test
logic.

TDI

Input

Serial test instructions and data are received by the test
logic at test data input (TDI).

TMS

Input

The signal received at test mode select (TMS) is
decoded by the TAP controller to control test operations.

TDO

Output

Test data output (TDO) is the serial output for test
instructions and data from the test logic.

nTRST

Input
(optional)

The optional test reset (nTRST) input provides for asynchronous initialization of the TAP controller.

Table 13.1: Test access port

13.1.2 Data registers
JTAG requires at least two data registers to be present: the bypass and the boundary-scan register. Other registers are allowed but are not obligatory.

Bypass data register
A single-bit register that passes information from TDI to TDO.

Boundary-scan data register
A test data register which allows the testing of board interconnections, access to
input and output of components when testing their system logic and so on.

13.1.3 Instruction register
The instruction register holds the current instruction and its content is used by the
TAP controller to decide which test to perform or which data register to access. It
consist of at least two shift-register cells.

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13.1.4 The TAP controller
The TAP controller is a synchronous finite state machine that responds to changes at
the TMS and TCK signals of the TAP and controls the sequence of operations of the
circuitry.

TAP controller state diagram
Reset
tm s=1
tm s=0

Idle

tm s=1

tm s=1

DR-Scan

tm s=0

tm s=0
tm s=1

tm s=0
tm s=1

Capture-DR

Capture-IR

tm s=0

tm s=0

Shift-DR
tm s=1

tm s=1

IR-Scan

Shift-IR
tm s=0

tm s=1

Exit1-DR

tm s=0

Exit1-IR
tm s=1

tm s=1

tm s=0

tm s=0

Pause-DR
tm s=1
tm s=0

Pause-IR
tm s=0

Exit2-DR

tm s=1
tm s=0

Exit2-IR

tm s=1

tm s=1

Update-DR

Update-IR

tm s=1

tm s=0

tm s=0

tm s=1

tm s=0

13.1.4.1 State descriptions
Reset
The test logic is disabled so that normal operation of the chip logic can continue
unhindered. No matter in which state the TAP controller currently is, it can change
into Reset state if TMS is high for at least 5 clock cycles. As long as TMS is high, the
TAP controller remains in Reset state.

Idle
Idle is a TAP controller state between scan (DR or IR) operations. Once entered, this
state remains active as long as TMS is low.

DR-Scan
Temporary controller state. If TMS remains low, a scan sequence for the selected
data registers is initiated.

IR-Scan
Temporary controller state. If TMS remains low, a scan sequence for the instruction
register is initiated.

Capture-DR
Data may be loaded in parallel to the selected test data registers.

Shift-DR
The test data register connected between TDI and TDO shifts data one stage towards
the serial output with each clock.
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Exit1-DR
Temporary controller state.

Pause-DR
The shifting of the test data register between TDI and TDO is temporarily halted.

Exit2-DR
Temporary controller state. Allows to either go back into Shift-DR state or go on to
Update-DR.

Update-DR
Data contained in the currently selected data register is loaded into a latched parallel
output (for registers that have such a latch). The parallel latch prevents changes at
the parallel output of these registers from occurring during the shifting process.

Capture-IR
Instructions may be loaded in parallel into the instruction register.

Shift-IR
The instruction register shifts the values in the instruction register towards TDO with
each clock.

Exit1-IR
Temporary controller state.

Pause-IR
Wait state that temporarily halts the instruction shifting.

Exit2-IR
Temporary controller state. Allows to either go back into Shift-IR state or go on to
Update-IR.

Update-IR
The values contained in the instruction register are loaded into a latched parallel output from the shift-register path. Once latched, this new instruction becomes the current one. The parallel latch prevents changes at the parallel output of the instruction
register from occurring during the shifting process.

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13.2 Embedded Trace Macrocell (ETM)
Embedded Trace Macrocell (ETM) provides comprehensive debug and trace facilities
for ARM processors. ETM allows to capture information on the processor's state without affecting the processor's performance. The trace information is exported immediately after it has been captured, through a special trace port.
Microcontrollers that include an ETM allow detailed program execution to be recorded
and saved in real time. This information can be used to analyze program flow and
execution time, perform profiling and locate software bugs that are otherwise very
hard to locate. A typical situation in which code trace is extremely valuable, is to find
out how and why a "program crash" occurred in case of a runaway program count.
A debugger provides the user interface to J-Trace and the stored trace data. The
debugger enables all the ETM facilities and displays the trace information that has
been captured. J-Trace is seamlessly integrated into the IAR Embedded Workbench®
IDE. The advanced trace debugging features can be used with the IAR C-SPY debugger.

13.2.1 Trigger condition
The ETM can be configured in software to store trace information only after a specific
sequence of conditions. When the trigger condition occurs the trace capture stops
after a programmable period.

13.2.2 Code tracing and data tracing
Code trace
Code tracing means that the processor outputs trace data which contain information
about the instructions that have been executed at last.

Data trace
Data tracing means that the processor outputs trace data about memory accesses
(read / write access to which address and which data has been read / stored). In
general, J-Trace supports data tracing, but it depends on the debugger if this option
is available or not. Note that when using data trace, the amount of trace data to be
captured rises enormously.

13.2.3 J-Trace integration example - IAR Embedded Workbench for ARM
In the following a sample integration of J-Trace and the trace functionality on the
debugger side is shown. The sample is based on IAR’s Embedded Workbench for ARM
integration of J-Trace.

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13.2.3.1 Code coverage - Disassembly tracing

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13.2.3.2 Code coverage - Source code tracing

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13.3 Embedded Trace Buffer (ETB)
The ETB is a small, circular on-chip memory area where trace information is stored
during capture. It contains the data which is normally exported immediately after it
has been captured from the ETM. The buffer can be read out through the JTAG port of
the device once capture has been completed. No additional special trace port is
required, so that the ETB can be read via J-Link. The trace functionality via J-Link is
limited by the size of the ETB. While capturing runs, the trace information in the
buffer will be overwritten every time the buffer size has been reached.

The result of the limited buffer size is that not more data can be traced than the
buffer can hold. Because of this limitation, an ETB is not a fully- alternative to the
direct access to an ETM via J-Trace.

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13.4 Flash programming
J-Link / J-Trace comes with a DLL, which allows - amongst other functionalities reading and writing RAM, CPU registers, starting and stopping the CPU, and setting
breakpoints. The standard DLL does not have API functions for flash programming.
However, the functionality offered can be used to program the flash. In that case, a
flashloader is required.

13.4.1 How does flash programming via J-Link / J-Trace work?
This requires extra code. This extra code typically downloads a program into the RAM
of the target system, which is able to erase and program the flash. This program is
called RAM code and "knows" how to program the flash; it contains an implementation of the flash programming algorithm for the particular flash. Different flash chips
have different programming algorithms; the programming algorithm also depends on
other things such as endianess of the target system and organization of the flash
memory (for example 1 * 8 bits, 1 * 16 bits, 2 * 16 bits or 32 bits). The RAM code
requires data to be programmed into the flash memory. There are 2 ways of supplying this data: Data download to RAM or data download via DCC.

13.4.2 Data download to RAM
The data (or part of it) is downloaded to another part of the RAM of the target system. The Instruction pointer (R15) of the CPU is then set to the start address of the
RAM code, the CPU is started, executing the RAM code. The RAM code, which contains the programming algorithm for the flash chip, copies the data into the flash
chip. The CPU is stopped after this. This process may have to be repeated until the
entire data is programmed into the flash.

13.4.3 Data download via DCC
In this case, the RAM code is started as described above before downloading any
data. The RAM code then communicates with the host computer (via DCC, JTAG and
J-Link / J-Trace), transferring data to the target. The RAM code then programs the
data into flash and waits for new data from the host. The WriteMemory functions of JLink / J-Trace are used to transfer the RAM code only, but not to transfer the data.
The CPU is started and stopped only once. Using DCC for communication is typically
faster than using WriteMemory for RAM download because the overhead is lower.

13.4.4 Available options for flash programming
There are different solutions available to program internal or external flashes connected to ARM cores using J-Link / J-Trace. The different solutions have different
fields of application, but of course also some overlap.

13.4.4.1 J-Flash - Complete flash programming solution
J-Flash is a stand-alone Windows application, which can read / write data files and
program the flash in almost any ARM system. J-Flash requires an extra license from
SEGGER.

13.4.4.2 RDI flash loader: Allows flash download from any RDI-compliant
tool chain
RDI (Remote debug interface) is a standard for "debug transfer agents" such as JLink. It allows using J-Link from any RDI compliant debugger. RDI by itself does not
include download to flash. To debug in flash, you need to somehow program your
application program (debuggee) into the flash. You can use J-Flash for this purpose,
use the flash loader supplied by the debugger company (if they supply a matching
flash loader) or use the flash loader integrated in the J-Link RDI software. The RDI
software as well as the RDI flash loader require licenses from SEGGER.
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13.4.4.3 Flash loader of compiler / debugger vendor such as IAR
A lot of debuggers (some of them integrated into an IDE) come with their own flash
loaders. The flash loaders can of course be used if they match your flash configuration, which is something that needs to be checked with the vendor of the debugger.

13.4.4.4 Write your own flash loader
Implement your own flash loader using the functionality of the JLinkARM.dll as
described above. This can be a time consuming process and requires in-depth knowledge of the flash programming algorithm used as well as of the target system.

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13.5 J-Link / J-Trace firmware
The heart of J-Link / J-Trace is a microcontroller. The firmware is the software executed by the microcontroller inside of the J-Link / J-Trace. The J-Link / J-Trace firmware sometimes needs to be updated. This firmware update is performed
automatically as necessary by the JLinkARM.dll.

13.5.1 Firmware update
Every time you connect to J-Link / J-Trace, JLinkARM.dll checks if its embedded firmware is newer than the one used the J-Link / J-Trace. The DLL will then update the
firmware automatically. This process takes less than 3 seconds and does not require
a reboot.
It is recommended that you always use the latest version of JLinkARM.dll.

In the screenshot:
•
•

The red box identifies the new firmware.
The green box identifies the old firmware which has been replaced.

13.5.2 Invalidating the firmware
Downdating J-Link / J-Trace is not performed automatically through an old
JLinkARM.dll.
J-Link / J-Trace will continue using its current, newer firmware when
using older versions of the JLinkARM.dll.
Note:
risk!

Downdating J-Link / J-Trace is not recommended, you do it at your own

Note:
Note also the firmware embedded in older versions of JLinkARM.dll might
not execute properly with newer hardware versions.

To downdate J-Link / J-Trace, you need to invalidate the current J-Link / J-Trace firmware, using the command exec InvalidateFW.

In the screenshot, the red box contains information about the formerly used J-Link /
J-Trace firmware version.
Use an application (for example JLink.exe) which uses the desired version of
JLinkARM.dll. This automatically replaces the invalidated firmware with its embedded
firmware.

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In the screenshot:
•
•

The red box identifies the new firmware.
The green box identifies the old firmware which has been replaced.

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Chapter 14
Designing the target board for
trace

This chapter describes the hardware requirements which have to be met by the target board.

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Designing the target board for trace

14.1 Overview of high-speed board design
Failure to observe high-speed design rules when designing a target system containing an ARM Embedded Trace Macrocell (ETM) trace port can result in incorrect data
being captured by J-Trace.You must give serious consideration to high-speed signals
when designing the target system.
The signals coming from an ARM ETM trace port can have very fast rise and fall
times, even at relatively low frequencies.
Note:
These principles apply to all of the trace port signals (TRACEPKT[0:15],
PIPESTAT[0:2], TRACESYNC), but special care must be taken with TRACECLK.

14.1.1 Avoiding stubs
Stubs are short pieces of track that tee off from the main track carrying the signal to,
for example, a test point or a connection to an intermediate device. Stubs cause
impedance discontinuities that affect signal quality and must be avoided.
Special care must therefore be taken when ETM signals are multiplexed with other
pin functions and where the PCB is designed to support both functions with differing
tracking requirements.

14.1.2 Minimizing Signal Skew (Balancing PCB Track Lengths)
You must attempt to match the lengths of the PCB tracks carrying all of TRACECLK,
PIPESTAT, TRACESYNC, and TRACEPKT from the ASIC to the mictor connector to be
within approximately 0.5 inches (12.5mm) of each other. Any greater differences
directly impact the setup and hold time requirements.

14.1.3 Minimizing Crosstalk
Normal high-speed design rules must be observed. For example, do not run dynamic
signals parallel to each other for any significant distance, keep them spaced well
apart, and use a ground plane and so forth. Particular attention must be paid to the
TRACECLK signal. If in any doubt, place grounds or static signals between the
TRACECLK and any other dynamic signals.

14.1.4 Using impedance matching and termination
Termination is almost certainly necessary, but there are some circumstances where it
is not required. The decision is related to track length between the ASIC and the
JTAG+Trace connector, see Terminating the trace signal on page 377 for further reference.

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14.2 Terminating the trace signal
To terminate the trace signal, you can choose between three termination options:
•
•
•

Matched impedance.
Series (source) termination.
DC parallel termination.

Matched impedance
Where available, the best termination scheme is to have the ASIC manufacturer
match the output impedance of the driver to the impedance of the PCB track on your
board. This produces the best possible signal.

Series (source) termination
This method requires a resistor fitted in series with signal. The resistor value plus the
output impedance of the driver must be equal to the PCB track impedance.

DC parallel termination
This requires either a single resistor to ground, or a pull-up/pull-down combination of
resistors (Thevenin termination), fitted at the end of each signal and as close as possible to the JTAG+Trace connector. If a single resistor is used, its value must be set
equal to the PCB track impedance. If the pull-up/pull-down combination is used, their
resistance values must be selected so that their parallel combination equals the PCB
track impedance.
Caution:

At lower frequencies, parallel termination requires considerably more drive capability
from the ASIC than series termination and so, in practice, DC parallel termination is
rarely used.

14.2.1 Rules for series terminators
Series (source) termination is the most commonly used method. The basic rules are:
1.
2.
3.

The series resistor must be placed as close as possible to the ASIC pin (less than
0.5 inches).
The value of the resistor must equal the impedance of the track minus the output
impedance of the output driver. So for example, a 50 PCB track driven by an output with a 17 impedance, requires a resistor value of 33.
A source terminated signal is only valid at the end of the signal path. At any point
between the source and the end of the track, the signal appears distorted
because of reflections. Any device connected between the source and the end of
the signal path therefore sees the distorted signal and might not operate correctly. Care must be taken not to connect devices in this way, unless the distortion does not affect device operation.

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14.3 Signal requirements
The table below lists the specifications that apply to the signals as seen at the
JTAG+Trace connector.
Signal

Fmax
Ts setup time (min.)
Th hold time (min.)
TRACECLK high pulse width (min.)
TRACECLK high pulse width (min.)

Value

200MHz
2.0ns
1.0ns
1.5ns
1.5ns

Table 14.1: Signal requirements

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Chapter 15
Support and FAQs

This chapter contains troubleshooting tips as well as solutions for common problems
which might occur when using J-Link / J-Trace. There are several steps you can take
before contacting support. Performing these steps can solve many problems and
often eliminates the need for assistance. This chapter also contains a collection of
frequently asked questions (FAQs) with answers.

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CHAPTER 15

Support and FAQs

15.1 Measuring download speed
15.1.1 Test environment
JLink.exe has been used for measurement performance. The hardware consisted of:
•
•
•
•
•

PC with 2.6 GHz Pentium 4, running Win2K
USB 2.0 port
USB 2.0 hub
J-Link
Target with ARM7 running at 50MHz

Below is a screenshot of JLink.exe after the measurement has been performed.

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15.2 Troubleshooting
15.2.1 General procedure
If you experience problems with J-Link / J-Trace, you should follow the steps below to
solve these problems:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.

Close all running applications on your host system.
Disconnect the J-Link / J-Trace device from USB.
Disable power supply on the target.
Re-connect J-Link / J-Trace with the host system (attach USB cable).
Enable power supply on the target.
Try your target application again. If the problem remains continue the following
procedure.
Close all running applications on your host system again.
Disconnect the J-Link / J-Trace device from USB.
Disable power supply on the target.
Re-connect J-Link / J-Trace with the host system (attach the USB cable).
Enable power supply on the target.
Start JLink.exe.
If JLink.exe displays the J-Link / J-Trace serial number and the target processor’s core ID, the J-Link / J-Trace is working properly and cannot be the cause of
your problem.
If the problem persists and you own an original product (not an OEM version),
see section Contacting support on page 383.

15.2.2 Typical problem scenarios
J-Link / J-Trace LED is off
Meaning:

The USB connection does not work.
Remedy:

Check the USB connection. Try to re-initialize J-Link / J-Trace by disconnecting and
reconnecting it. Make sure that the connectors are firmly attached. Check the cable
connections on your J-Link / J-Trace and the host computer. If this does not solve the
problem, check if your cable is defective. If the USB cable is ok, try a different host
computer.

J-Link / J-Trace LED is flashing at a high frequency
Meaning:

J-Link / J-Trace could not be enumerated by the USB controller.
Most likely reasons:

a.) Another program is already using J-Link / J-Trace.
b.) The J-Link USB driver does not work correctly.
Remedy:

a.) Close all running applications and try to reinitialize J-Link / J-Trace by disconnecting and reconnecting it.
b.) If the LED blinks permanently, check the correct installation of the J-Link USB
driver. Deinstall and reinstall the driver as shown in chapter Setup on page 139.

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J-Link/J-Trace does not get any connection to the target
Most likely reasons:

a.) The JTAG cable is defective.
b.) The target hardware is defective.
Remedy:

Follow the steps described in General procedure on page 381.

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15.3 Contacting support
Before contacting support, make sure you tried to solve your problem by following
the steps outlined in section General procedure on page 381. You may also try your
J-Link / J-Trace with another PC and if possible with another target system to see if it
works there. If the device functions correctly, the USB setup on the original machine
or your target hardware is the source of the problem, not J-Link / J-Trace.
If you need to contact support, send the following information to
support@segger.com:
•
•
•
•
•

A detailed description of the problem.
J-Link/J-Trace serial number.
Output of JLink.exe if available.
Your findings of the signal analysis.
Information about your target hardware (processor, board, etc.).

J-Link / J-Trace is sold directly by SEGGER or as OEM-product by other vendors. We
can support only official SEGGER products.

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15.4 Frequently Asked Questions
Supported CPUs
Q:
A:

Which CPUs are supported?
J-Link / J-Trace should work with any ARM7/9 and Cortex-M3 core. For a list of
supported cores, see section Supported CPU cores on page 43.

Converting data files
Q:
A:

I want to download my application into flash memory using J-Link Commander but
my application is a *.hex data file and J-Link Commander supports *.bin files only.
How do I download it?
Please use the J-Flash (which is part of the J-Link software and documentation
package) software to convert your *.hex/*.mot/... file to a *.bin file. For data file
conversion, no J-Flash license is necessary.

Using J-Link in my application
Q:
A:

I want to write my own application and use J-Link / J-Trace. Is this possible?
Yes. We offer a dedicated Software Developer Kit (SDK). See section J-Link Software Developer Kit (SDK) on page 138 for further information.

Using DCC with J-Link
Q:
A:

Can I use J-Link / J-Trace to communicate with a running target via DCC?
Yes. The DLL includes functions to communicate via DCC on cores which support
DCC, such as ARM7/9/11, Cortex A/R series.

Read status of JTAG pins
Q:
A:

Can J-Link / J-Trace read back the status of the JTAG pins?
Yes, the status of all pins can be read. This includes the outputs of J-Link / J-Trace
as well as the supply voltage, which can be useful to detect hardware problems on
the target system.

J-Link support of ETM
Q:
A:

Does J-Link support the Embedded Trace Macrocell (ETM)?
No. ETM requires another connection to the ARM chip and a CPU with built-in ETM.
Most current ARM7 / ARM9 chips do not have ETM built-in.

J-Link support of ETB
Q:
A:

Does J-Link support the Embedded Trace Buffer (ETB)?
Yes. J-Link supports ETB. Most current ARM7 / ARM9 chips do not have ETB builtin.

Registers on ARM 7 / ARM 9 targets
Q:
A:

I’m running J-Link.exe in parallel to my debugger, on an ARM 7 target. I can read
memory okay, but the processor registers are different. Is this normal?
If memory on an ARM 7/9 target is read or written the processor registers are
modified. When memory read or write operations are performed, J-Link preserves
the register values before they are modified. The register values shown in the
debugger’s register window are the preserved ones. If a second instance, in this
case J-Link.exe , reads the processor registers, it reads the values from the hardware, which are the modified ones. This is why it shows different register values.

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Chapter 16
Glossary

This chapter describes important terms used throughout this manual.

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Glossary

Adaptive clocking
A technique in which a clock signal is sent out by J-Link / J-Trace. J-Link / J-Trace
waits for the returned clock before generating the next clock pulse. The technique
allows the J-Link / J-Trace interface unit to adapt to differing signal drive capabilities
and differing cable lengths.

Application Program Interface
A specification of a set of procedures, functions, data structures, and constants that
are used to interface two or more software components together.

Big-endian
Memory organization where the least significant byte of a word is at a higher address
than the most significant byte. See Little-endian.

Cache cleaning
The process of writing dirty data in a cache to main memory.

Coprocessor
An additional processor that is used for certain operations, for example, for floatingpoint math calculations, signal processing, or memory management.

Dirty data
When referring to a processor data cache, data that has been written to the cache
but has not been written to main memory is referred to as dirty data. Only write-back
caches can have dirty data because a write-through cache writes data to the cache
and to main memory simultaneously. See also cache cleaning.

Dynamic Linked Library (DLL)
A collection of programs, any of which can be called when needed by an executing
program. A small program that helps a larger program communicate with a device
such as a printer or keyboard is often packaged as a DLL.

Embedded Trace Macrocell (ETM)
ETM is additional hardware provided by debuggable ARM processors to aid debugging
with trace functionality.

Embedded Trace Buffer (ETB)
ETB is a small, circular on-chip memory area where trace information is stored during
capture.

EmbeddedICE
The additional hardware provided by debuggable ARM processors to aid debugging.

Halfword
A 16-bit unit of information. Contents are taken as being an unsigned
unless otherwise stated.

integer

Host
A computer which provides data and other services to another computer. Especially, a
computer providing debugging services to a target being debugged.

ICache
Instruction cache.

ICE Extension Unit
A hardware extension to the EmbeddedICE logic that provides more breakpoint units.

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ID
Identifier.

IEEE 1149.1
The IEEE Standard which defines TAP. Commonly (but incorrectly) referred to as
JTAG.

Image
An executable file that has been loaded onto a processor for execution.

In-Circuit Emulator (ICE)
A device enabling access to and modification of the signals of a circuit while that circuit is operating.

Instruction Register
When referring to a TAP controller, a register that controls the operation of the TAP.

IR
See Instruction Register.

Joint Test Action Group (JTAG)
The name of the standards group which created the IEEE 1149.1 specification.

Little-endian
Memory organization where the least significant byte of a word is at a lower address
than the most significant byte. See also Big-endian.

Memory coherency
A memory is coherent if the value read by a data read or instruction fetch is the
value that was most recently written to that location. Obtaining memory coherency is
difficult when there are multiple possible physical locations that are involved, such as
a system that has main memory, a write buffer, and a cache.

Memory management unit (MMU)
Hardware that controls caches and access permissions to blocks of memory, and
translates virtual to physical addresses.

Memory Protection Unit (MPU)
Hardware that controls access permissions to blocks of memory. Unlike an MMU, an
MPU does not translate virtual addresses to physical addresses.

Multi-ICE
Multi-processor EmbeddedICE interface. ARM registered trademark.

RESET
Abbreviation of System Reset. The electronic signal which causes the target system
other than the TAP controller to be reset. This signal is also known as "nSRST"
"nSYSRST", "nRST", or "nRESET" in some other manuals. See also nTRST.

nTRST
Abbreviation of TAP Reset. The electronic signal that causes the target system TAP
controller to be reset. This signal is known as nICERST in some other manuals. See
also nSRST.

Open collector
A signal that may be actively driven LOW by one or more drivers, and is otherwise
passively pulled HIGH. Also known as a "wired AND" signal.

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Glossary

Processor Core
The part of a microprocessor that reads instructions from memory and executes
them, including the instruction fetch unit, arithmetic and logic unit, and the register
bank. It excludes optional coprocessors, caches, and the memory management unit.

Program Status Register (PSR)
Contains some information about the current program and some information about
the current processor state. Therefore often referred to as Processor Status Register.
Also referred to as Current PSR (CPSR), to emphasize the distinction to the Saved
PSR (SPSR). The SPSR holds the value the PSR had when the current function was
called, and which will be restored when control is returned.

Remapping
Changing the address of physical memory or devices after the application has started
executing. This is typically done to make RAM replace ROM once the initialization has
been done.

Remote Debug Interface (RDI)
RDI is an open ARM standard procedural interface between a debugger and the
debug agent. The widest possible adoption of this standard is encouraged.

RTCK
Returned TCK. The signal which enables Adaptive Clocking.

RTOS
Real Time Operating System.

Scan Chain
A group of one or more registers from one or more TAP controllers connected
between TDI and TDO, through which test data is shifted.

Semihosting
A mechanism whereby the target communicates I/O requests made in the application
code to the host system, rather than attempting to support the I/O itself.

SWI
Software Interrupt. An instruction that causes the processor to call a programerspecified subroutine. Used by ARM to handle semihosting.

TAP Controller
Logic on a device which allows access to some or all of that device for test purposes.
The circuit functionality is defined in IEEE1149.1.

Target
The actual processor (real silicon or simulated) on which the application program is
running.

TCK
The electronic clock signal which times data on the TAP data lines TMS, TDI, and
TDO.

TDI
The electronic signal input to a TAP controller from the data source (upstream). Usually, this is seen when connecting the J-Link / J-Trace Interface Unit to the first TAP
controller.

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TDO
The electronic signal output from a TAP controller to the data sink (downstream).
Usually, this is seen connecting the last TAP controller to the J-Link / J-Trace Interface Unit.

Test Access Port (TAP)
The port used to access a device's TAP Controller. Comprises TCK, TMS, TDI, TDO,
and nTRST (optional).

Transistor-Transistor logic (TTL)
A type of logic design in which two bipolar transistors drive the logic output to one or
zero. LSI and VLSI logic often used TTL with HIGH logic level approaching +5V and
LOW approaching 0V.

Watchpoint
A location within the image that will be monitored and that will cause execution to
stop when it changes.

Word
A 32-bit unit of information. Contents are taken as being an unsigned integer unless
otherwise stated.

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J-Link / J-Trace (UM08001)

CHAPTER 16

Glossary

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Chapter 17
Literature and references

This chapter lists documents, which we think may be useful to gain deeper understanding of technical details.

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CHAPTER 17

Reference

Title

Literature and references

Comments

[ETM]

Embedded Trace Macrocell™
Architecture Specification,
ARM IHI 0014J

[RVI]

RealView® ICE and RealView
Trace User Guide, ARM DUI
0155C

This document defines the ETM
standard, including signal protocol
and physical interface.
It is publicly available from ARM
( www.arm.com ).
This document describes ARM’s
realview ice emulator and requirements on the target side.
It is publicly available from ARM
( www.arm.com ).

Table 17.1: Literature and References

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Index

A
Adaptive clocking ............................... 386
Application Program Interface .............. 386

B
Big-endian ........................................ 386

C
Cache cleaning .................................. 386
Coprocessor ...................................... 386

D
Dirty data ......................................... 386
Dynamic Linked Library (DLL) .............. 386

J-Link
Adapters ........................................359
Developer Pack DLL .........................138
Supported chips ........ 212–213, 226–227
J-Link Commander .............................. 65
J-Link GDB Server ............................... 83
J-Link RDI .........................................133
J-Link STR9 Commander .....................134
J-Link TCP/IP Server ...........................116
J-Mem Memory Viewer ........................120
Joint Test Action Group (JTAG) .............387
JTAG ........................................ 240, 362
TAP controller ..................................363
JTAGLoad ..........................................132

L

E

Little-endian ......................................387

Embedded Trace Buffer (ETB) .......369, 386
Embedded Trace Macrocell (ETM) ..365, 386
EmbeddedICE ................................... 386

M

General Query Packets ....................... 101

Memory coherency .............................387
Memory management unit (MMU) ........387
Memory Protection Unit (MPU) .............387
Menu structure ..................................235
Multi-ICE ..........................................387

H

N

G

Halfword ........................................... 386
Host ................................................. 386

I
ICache ............................................. 386
ICE Extension Unit ............................. 386
ID ................................................... 387
IEEE 1149.1 ...................................... 387
Image .............................................. 387
In-Circuit Emulator ............................ 387
Instruction Register ............................ 387
IR .................................................... 387

J
J-Flash ARM ...................................... 121

J-Link / J-Trace (UM08001)

nTRST ...................................... 344, 387

O
Open collector ...................................387

P
Processor Core ..................................388
Program Status Register (PSR) ............388

R
RDI Support ......................................133
Remapping ........................................388
Remote Debug Interface (RDI) .............388
RESET ..............................................387
RTCK ................................................388
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Index

RTOS ............................................... 388

S
Scan Chain ....................................... 388
Semihosting ..................................... 388
Server command
clrbp ............................................... 91
cp15 ............................................... 91
DisableChecks .................................. 91
EnableChecks ................................... 92
flash breakpoints .............................. 92
go ................................................... 92
halt ................................................. 93
jtagconf ........................................... 93
memU16 .......................................... 94
memU8 ........................................... 93
reg ................................................. 94
reset ............................................... 95
setBP ......................................... 95–97
sleep ............................................... 98
speed .............................................. 98
step ................................................ 98
waithalt ......................................... 100
wice .............................................. 100
SetDbgPowerDownOnClose ................. 204
SetSysPowerDownOnIdle .................... 204
STRACE ........................................... 102
Support .................................... 379, 385
Supported flash devices 214–215, 221, 228
SWI ................................................. 388
Syntax, conventions used ..................... 13

T
Tabs ................................................
TAP Controller ...................................
Target ..............................................
TCK .......................................... 344,
TCP/IP .............................................
TDI .......................................... 344,
TDO ......................................... 344,
Test Access Port (TAP) ........................
Transistor-transistor logic (TTL) ...........

175
388
388
388
239
388
389
389
389

U
USB ................................................. 239

W
Watchpoint ....................................... 389
Word ............................................... 389

J-Link / J-Trace (UM08001)

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