emWin upgrade     Trade-In program     Web shop

Debug Probes - J-Link and J-Trace


SEGGER J-Links are the most widely used line of debug probes available today. They've proven their value for more than 10 years with over 400,000 units sold, including OEM versions and on-board solutions. This popularity stems from the unparalleled performance, extensive feature set, large number of supported CPUs, and compatibility with all popular development environments.

With up to 3 MBytes/s download speed to RAM and record breaking flashloaders, as well as the ability to set an unlimited number of breakpoints in flash memory of MCUs, the J-Link debug probes are undoubtedly the best choice to optimize your debugging and flash programming experience.  


J-Link debug probes support ARM 7/9/11, Cortex™, Microchip PIC32™, Renesas RX™ CPUs and are supported by all major IDEs such as Keil MDK-ARM, GDB-based IDEs and SEGGER Embedded Studio. Here is the complete list of IDEs fully supporting J-Link / J-Trace.

Debug smarter and faster with J-Link debug probes!


Software and Documentation download

Subscribe to the J-Link software update notification list

The J-Link firmware was developed with SEGGER's own embedded software, giving its design a unique advantage.


Model Overview

There is a J-Link or J-Trace model available to fit all project needs. J-Trace is a full superset of J-Link with the added benefit of trace capabilities. J-Trace models are designed for one particular family of cores.

Available models vary in price, speed, and other hardware features such as built-in trace memory and on-board Ethernet, as well as advanced software features. The advanced software features are

For a detailed overview of hardware and software features of our J-Link and J-Trace models, please visit the Model comparison.

Model Price4 Download Speed
into RAM5
Into Flash1
GDB Server Unlimited Flash
J-Flash RDI /
J-Link PRO 798 EUR
998 USD
3.0 MByte/sec
J-Link ULTRA+2 598 EUR
748 USD
3.0 MByte/sec
J-Link PLUS 498 EUR
598 USD
1.0 MByte/sec
J-Link BASE 298 EUR
378 USD
1.0 MByte/sec
J-Link EDU3 42 EUR
60 USD
1.0 MByte/sec
Debug probes with built-in Trace memory
J-Trace PRO Cortex-M 1,390 EUR
1,748 USD
3.0 MByte/sec
J-Trace Cortex-M 995 EUR
1248 USD
3.0 MByte/sec

Included          Not included

1 For use from within an IDE
2 Best value: Includes all software enhancements and maximum performance
3 Educational use
4 Price does not include VAT or Sales Tax which may be applicable in some regions
5 The download speeds listed here are the peak download speeds that can be achieved by the particular J-Link model. The actual download speed may be lower as it depends on various factors, such as, but not limited to: The selected debug interface & speed, the CPU core and its operating frequency, other devices in the JTAG chain in case JTAG is used as target interface.


Product Demonstration Videos

SEGGER: Flash Breakpoint Introduction
Allows setting an unlimited
number of breakpoints in flash
SEGGER J-Flash Introduction
High-speed production programming
software available (J-Flash)
J-Link vs I-jet Speed Comparison
Ultra high speed flash programming


J-Link Features

  • The de-facto standard debug probe (J-Link, more than 400,000 units have been sold so far)
  • Up to 3 MByte/s Download speed!
  • Intelligence in the emulator firmware
  • Compatible with all popular tool chains
  • Support for multi core debugging
  • Supports an unlimited number of software breakpoints in flash memory
  • Setting breakpoints in external flash memory of Cortex-M systems is possible with
    J-Link's Unlimited Flash Breakpoints technology only!
  • Cross platform support (Microsoft Windows, Linux, Mac OS X)
  • Supports concurrent access to CPU by multiple applications
  • Remote Server included. Allows using J-Link remotely via TCP/IP
  • All CPU families supported by the J-Link software can be used without additional license
  • No charges for software updates
  • RDI / RDDI interface DLL available
  • Software comes with free GDBServer, allowing usage of J-Link with all GDB-based debug solutions
  • Production flash programming software (J-Flash) available
  • Debugger independent flash download (internal flash, CFI flash, SPIFI flash)
  • Supports CPU/MCU internal trace buffer (ETB, MTB, ...)
  • Supports ETM tracing (J-Trace Cortex-M, J-Trace ARM)
  • Can be connected to the host PC via USB or Ethernet (J-Link PRO)
  • No power supply required, powered through USB
  • Wide target voltage range: 1.2V - 3.3V, 5V tolerant
  • All JTAG signals can be monitored, target voltage can be measured
  • Target power supply: J-Link can supply up to 300 mA to target with overload protection
  • An SDK is available (Allows customized use of J-Link)
  • Various target adapters and optical isolation adapters available
  • Supports multiple target interfaces (JTAG, SWD, FINE, SPD, ...)


Supported CPUs

J-Link supports a wide range of CPU cores that spreads over

  • ARM Cortex-M
  • ARM Cortex-A
  • ARM Cortex-R
  • Legacy ARM cores (ARM 7, 9, ...)
  • Microchip PIC32
  • Renesas RX

For a detailed list of which cores exactly are supported, please refer to the list of supported cores and devices.

Direct download into flash memory of most popular microcontrollers supported

J-Link can program the internal flash of almost all popular microcontrollers as well as external CFI compliant flashes. From a debugger perspective, the flash area can be treated just like RAM, so this great feature works with basically any debugger, including GDB. More info...

Supports unlimited breakpoints in flash memory

Say goodbye to hardware breakpoint limitations! The J-Link offers unlimited breakpoints while debugging in flash memory free of charge for evaluation.

In Cortex-M systems, the typically 6 hardware breakpoints of the Flash-Patch Unit can NOT be used to set breakpoints in external memory, since the address range of the unit is limited.

This means: If you are using a Cortex-M3 or M4 with external flash, a program in this external flash can not be debugged with the popular emulators, except a J-Link with the "Unlimited Flash Breakpoint" license.

In other words: When debugging a program in external flash on a Cortex-M device, a J-Link with the "Unlimited Flash Breakpoint" license such as J-Link ULTRA+ is almost a must.

The evaluation period is not time limited. For commercial use a separate license is required. More info...

Supported by all major IDEs

All major IDEs have built-in direct support for J-Link.  J-Link GDB Server is also available free of charge for use with GNU based solutions. More info...

Free software updates

As a legitimate owner of a SEGGER J-Link, you can always download the latest software free of charge. Though not planned and not likely, we reserve the right to change this policy. Note that older models may not be supported by newer versions of the software. Typically, we support older models with new software at least 3 years after end of life. More info...

Supports concurrent access to CPU by multiple applications

J-Link allows multiple applications to access a CPU at the same time. This has numerous applications. J-Link commander can be used in parallel to a debugger, a tool to communicate via DCC can be used in parallel to a debugger or a visualization tool such as Micrium's u/C-Probe or SEGGER's kernel viewer embOSView. This feature is currently not available for Cortex A and R cores.

Crossplatform support (runs on Windows, Linux, Mac OS X)

The MAC and Linux versions are fully usable and contain the following components:

Intelligence in the emulator firmware

In contrast to other emulators (low-end FTDI-based emulators as well as some "high-end" emulators) J-Link has intelligence for different CPU cores in the emulator firmware. For most emulators, the CPU communication handling is completely done from the PC side while the emulator simply outputs some PC-generated sequences. This makes special handling for scenarios like "low-power" and "very slow CPU speed at very high debug interface speed" almost impossible to handle. Having an intelligent emulator firmware which is able to handle such cases itself, makes J-Link more robust in these situations.

Software Developer Kit (SDK) available

For customers who want to build their own applications using J-Link and for IDE vendors who implement J-Link support for their IDE, SEGGER offers a J-Link SDK which comes with the J-Link DLL + API documentation + implementation samples. The SDK is available for Windows and Linux. More info...

Supports multiple target interfaces

J-Link comes with support for multiple target interfaces. Currently, the following target interfaces are supported:

  • JTAG
  • SWD
  • FINE
  • SPD
  • ICSP

ARM7/9 devices only support the JTAG interface. With the introduction of the ARM Cortex devices, the SWD debug interface has been introduced and the number of devices supporting SWD is growing. SWD is a low-pin-count (actually 2 pins are needed) alternative debug interface to JTAG. FINE is a similar single wire interface introduced by Renesas. SPD is a single wire interface introduced by Infineon, ICSP a 2-wire JTAG interface introduced by Microchip.

Supports SWV/SWO

J-Link fully supports ARM's SWV/SWO feature which is available for most devices which support the SWD interface. SWO is a single pin output from the core which can be used to transfer terminal data (printf) as well as for data tracing (monitor variable read/write accesses).

Various target adapters available, including optical isolation adapter

There are several target interface connectors available on the market. To fit all needs, SEGGER offers various target interface adapters for J-Link including an optical isolation adapter for JTAG (J-Link JTAG Isolator) and SWD (J-Link SWD Isolator) which is connected between the target hardware and J-Link to provide electrical isolation. This is essential when the development tools are not connected to the same ground as the application. More info...

Flash programming

J-Link can program the internal flash of almost all popular microcontrollers as well as external CFI compliant flashes. From a debugger perspective, the flash area can be treated just like RAM, so this great feature works with basically any debugger, including GDB. More info...

Unlimited Flash Breakpoints

The J-Link software comes with an additional feature, called Unlimited Flash Breakpoints. Unlimited Flash Breakpoints allow the user to set an unlimited number of breakpoints when debugging in flash memory, rather than just the usual 2/4/6 (depending on CPU core) hardware breakpoints. More info...

Wireless connections

J-Link PRO can be used in a wireless configuration with the addition of a third-party Wi-Fi Bridge: