J-Link downloads

Installing the software will automatically install the J-Link USB drivers. It also offers to update applications which use the J-Link DLL.
Multiple versions of the J-Link software can be installed on the same PC without problems; they will co-exist in different directories.

J-Link software & documentation pack can also be used with J-Link KS, SAM-ICE, mIDASLink, DIGI JTAG Link and any other licensed J-Link compatible emulator.

Software and documentation pack V4.24f [9767 kb]

J-Link software & documentation pack includes: J-Link Commander (Simple command line utility, primarily for diagnostics and trouble shooting) J-Flash, including sample projects for most popular eval boards GDB Server (extra license required) - Support for GDB and other debuggers using the same protocol. Fully usable in eval mode without time or code size limit. J-Mem - Simple memory viewer J-Link RDI (extra license required) - Support for ARM RDI standard. Makes J-Link compatible with RDI compliant debuggers J-Link DLL Updater - Allows to update 3rd party applications which use the J-Link DLL J-Link TCP/IP Server - Free utility which provides the possibility to use J-Link / J-Trace remotely via TCP/IP. JLinkARM.dll, used by most applications to access J-Link JLinkARM.dll comes with flash breakpoint capabilities (extra license required) Free flash programming utilities - Simple command line utilities which allow programming a bin file into the internal/external flash memory of popular eval boards Processor specific utilities - Small command line utilities which allow some processor specific operations (unsecure of internal flash memory, boot bank switching, ...) Manuals: UM08001 (J-Link User Guide), UM08003 (J-Flash User Guide), UM08004 (RDI User Guide), UM08005 (GDB Server User Guide), UM08007 (Flasher ARM User Guide) Release notes for J-Link DLL, J-Flash, J-Link RDI DLL Sample code for DCC communication USB driver

Latest J-Link DLL release notes
Latest J-Flash release notes
Latest J-Link RDI DLL release notes

Beta software

We frequently publish new Beta versions. The Beta versions follow our current development version very closely and contain the latest features and improvements.
However, the Beta versions are not thoroughly tested, but it is usually safe to assume that the Beta version can be used without risk.

Beta software version
Beta software version for Linux

Previous software versions

Manuals

	Manual	Version	Size
	Flasher ARM manual (UM08007)	Rev. 18	478 KB
	J-Flash manual (UM08003)	4.10 Rev. 3	439.24 KB
	J-Link manual (UM08001)	4.20 Rev.0	2105 KB
	J-Link GDB Server manual (UM08005)	4.08 Rev. 0	508.33 KB
	J-Link RDI manual (UM08004)	4.08 Rev. 0	796.85 KB
	J-Link USB Protocol manual (RM08001)	Rev. 6	337.48 KB

Terms of use

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.

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.
More information...

J-Link Flash Breakpoints

The J-Link software contains an additional feature, called Flash Breakpoints. Flash Breakpoints allow the user to set an unlimited number of software breakpoints when debugging in flash memory, rather than just the 2 hardware breakpoints. Setting the breakpoints in flash is executed very fast using a RAM code specifically designed for this purpose; on chips with fast flash, the difference between breakpoints in RAM and flash is unnoticeable. This feature requires an additional license from SEGGER.

Click to watch demonstration video

List of supported microcontrollers

How do breakpoints work?

There are basically 2 types of breakpoints in a computer system: Hard ones and soft ones. Hardware breakpoints require a dedicate hardware unit for every breakpoint. In other words, the hardware dictates how many hardware breakpoints can be set simultaneously. ARM7 and ARM 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, it requires the program to be located in RAM.

Using Flash Breakpoints

What is special about software breakpoints in flash?

Flash Breakpoints allow you to set an unlimited number of breakpoints even if your application program is not located in RAM, but in flash memory. This is a scenario which was very rare before ARM-microcontrollers hit the market. This new technology makes very powerful, yet inexpensive ARM microcontrollers available for systems, which required external RAM before. The downside of this new technology is that it is not possible to debug larger programs on these micros in RAM, since the RAM is not big enough to hold program and data (typically, these chips contain about 4 times as much flash as RAM), and therefore with standard debuggers, only 2 breakpoints can be set. The 2 breakpoint limit makes debugging very tough; a lot of times the debugger requires 2 breakpoints to simply step over a line of code. With software breakpoints in flash, this limitation is gone.

How does this work?

Basically very simple:
The J-Link software reprograms a sector of the flash to set or clear a breakpoint.

What performance can I expect ?

A RAMCode, specially designed for this purpose, sets and clears Flash Breakpoints extremely fast; on micros with fast flash the difference between 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 then 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 reprogramming 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, maximizing the life time of the flash. All resources of the ARM micro are available to the application program, no memory is lost for debugging. All of the optimizations described above can be disabled.

Licensing

The software is licensed on a per J-Link basis. It requires a J-Link with Flash Breakpoints. J-Link Flash Breakpoints can also be used with J-Link ARM RDI and J-Link GDB Server. If you want to use Flash Breakpoints with J-Link ARM RDI or J-Link GDB Server, you will need an additional license for these software components.

In order to receive your free 30 days trial license, please send an e-mail including the J-Link serial number to: このメールアドレスはスパムボットから保護されています。閲覧するにはJavaScriptを有効にする必要があります。 .

Using Flash Breakpoints with different software components

Flash Breakpoints can be used with the following J-Link software components:

• J-Link DLL (For example if you use the J-Link DLL natively in IAR Embedded Workbench for ARM or RealView^® MDK)
• J-Link ARM RDI
• J-Link GDB Server

For more information about how to use Flash Breakpoints with the different software components, please refer to the corresponding manuals.

Article about Flash Breakpoints in ARM's "I.Q." magazine

J-Link Flash Download

J-Link comes with a set of highly speed-optimized built-in flashloaders which allow fast download of applications, directly into the flash memory of your target system. This flash memory can be internal, on-chip flash memory or external CFI-compliant NOR flash memory.

And the best of all: This feature is free of charge.

What makes J-Link's built-in flash programming so much faster ?

The flashloaders which come with the J-Link software (JLinkARM.dll) are a set of so-called "RAMCodes" which are small programs that include the logic for erasing and programming the flash memory. These RAMCodes are downloaded into and are executed in the RAM of the target system.

But the flash-algorithm itself is not the only thing which makes the J-Link flashloaders so extremely fast. In addition to this, only the flash-sectors which are needed to be programmed are programmed by J-Link.

What does this mean?: By default, the J-Link DLL is configured to check if the same application which is intended to download, is already present in the flash of the target memory. If this is the case, the flash download it skipped which saves a lot of time. The process of checking if the target application is already in flash is also a highly speed-optimized process since this check is performed by a CRC comparison.

Moreover, if you are debugging, usually your target application continuously changes and the debug session is terminated and re-started multiple times. J-Link is also able to detect only small changes in your target application which means that only the parts which have been changed are re-downloaded if the debug session is re-started.

To get a better idea of what difference the above mentioned logic makes, in the following you will find a speed comparison test which has been performed with the J-Link flash download.

For the speed comparison test, a standard IAR EAWRM sample project and the maximum supported JTAG frequency (usually 12 MHz) has been used. All time values have been taken from the point where downloading starts until the debugger is ready to start debugging (application arrived at main()).

¹J-Link commander has been used as follows:
speed 20000
exec device = TMPM330FDFG
loadbin C:\TMPM330.bin,0

²J-Link commander has been used as follows:
speed 20000
exec device = MK40X256VMD100
loadbin C:\MK40.bin,0

³J-Link commander has been used as follows:
speed 20000
exec device = STM32F103ZE
loadbin C:\STM32.bin,0x08000000

Why do the speeds differ between different devices with the same CPU core?

Download speed into RAM is identical for all devices, but flash programming speed depends heavily on the flash technolgy and flash controller used. On most devices, J-Link speed is so high that the limiting factor is the time that it takes to erase the flash memory and to copy the data from RAM to flash.

Does the data above include the time it takes to erase the flash?

Yes, in all cases in which the flash is programmed the required sectors are also erased. This time is included.

Debuggers with support for J-Link flash download:

Currently, the flash download feature of J-Link is supported by the following debuggers/workbenches:

• IAR Embedded Workbench for ARM (IAR EWARM)
• Keil RealView MDK
• Yagarto GNU ARM Toolchain (free) + J-Link GDB Server
• GNU Debugger (GDB) + J-Link GDB Server
• RDI + any RDI compliant debugger

But in general, the flash download feature can be used with every workbench which supports J-Link, since even if it is not possible to select your target device in the debugger, you can always select it in the J-Link control panel, which is opened when a debug session starts.

Download into flash memory for production purposes

• Flasher ARM - Stand-alone flash programming solution. Flasher ARM is a programming tool for ARM/Cortex devices with internal or external flash memory. Flasher ARM is designed for programming flash targets with the J-Flash software or stand-alone. Flasher ARM can also operate as a normal J-Link.
• J-Flash - Complete flash programming solution. J-Flash is a Windows application, which can program internal and external flash on ARM/Cortex devices. J-Flash can be used as a GUI-based application or in batch mode.
• J-Link Flash SDK - An enhanced version of the J-Link SDK, which comes with an DLL with API functions for flash programming (erase, program verify). Ideally for customers which are planning to built their own application for production process.

Enabling J-Link built-in flashloaders in different debuggers

Usually, in order to enable the J-Link built-in flashloaders you only need to disable the debugger's flashloader. Since the built-in flashloaders of J-Link make flash behave as RAM , when the debugger writes to the target memory, the J-Link DLL automatically detects if the memory range which is written in flash memory or not. If the affected memory area is in flash memory, the J-Link flashloader will become active and performs the programming of the flash memory automatically in a very short time. Please note that the correct device has to be selected in the debugger in order to tell J-Link which device is intended to be programmed.

The following screenshot illustrates how to disable the IAR EWARM flashloader, in order to use the J-Link built-in flashloader.

J-Link ARM RDI

Support for RDI compatible ARM debuggers

The JLink-RDI software is an RDI interface for J-Link. It makes it possible to use J-Link with any RDI compliant debugger. The package consists of 2 DLLs, which need to be copied to the same folder. In order to use these DLLs, they need to be selected in the debugger. It is a separate item and not included in the J-Link software. For more information on the pricing please check out our Pricelist.

Software download

Supported ARM Debuggers

J-Link RDI can be used with any RDI-compliant debuggers. In the following all RDI compliant debuggers which have been tested with J-Link RDI are listed.

• ARM^® Developer Suite^™ (ADS)
• ARM^® RealView^® Development Suite (RVDS) V3.0 (Since RVDS 3.1 removed RDI support, J-Link RDI will not work with RVDS 3.1)
• IAR Embedded Workbench for ARM (EWARM)
• RealView^® Microcontroller Development Kit (Keil MDK)

For more information about how to use RDI with debuggers listed above, please refer to the J-Link RDI User's Guide (UM08004).

Flash breakpoints

The RDI DLL allows setting software breakpoints in flash memory areas, in the following called flash breakpoints. This makes it possible to set an unlimited number of flash breakpoints, rather than just the 2 hardware breakpoints permitted by the ICE. Setting flash breakpoints is executed very fast using a RAMcode specially designed for this purpose; on chips with fast flash the difference between breakpoints in RAM and Flash is unnoticeable.

More information about flash breakpoints

Configuration

RDI allows various configuartion settings, such as:

• Target system initialization via setup file
• JTAG Speed and scan chain settings
• Enable / disable Flash programming
• Breakpoint settings (use software breakpoints, use flash breakpoints
• CPU specific settings (Endianess, Reset strategy)
• Enable / Disable Logfiles

Commands in the setup file

Example of setup file

/*********************************************************************
*
*    Setup 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);