J-Link BASE is a USB-powered JTAG debug probe 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.

The J-Link debug probes are supported by all major IDEs including Eclipse, GDB-based IDEs and SEGGER Embedded Studio. For a complete list, please refer to supported IDEs. Including all models, more than 1,000,000 J-Links have been shipped so far, making J-Link probably the most popular debug probe for Arm cores and the de-facto standard.

Key features

  • Download speed up to 1 MB/s
  • Built-in VCOM functionality
  • Supports a broad range of microcontrollers
  • Free software updates

License upgrade

The J-Link BASE offers basic functionality. To use the full range of functions of a J-Link PLUS, for instance, the J-Link Upgrade BASE to PLUS is needed.

This license upgrade comes with a software bundle that includes the J-Flash  / J-Flash SPI license, software to program EEPROM and flash chips in Arm systems, as well as a J-Link Unlimited Flash Breakpoints license. Included is also the Ozone J-Link Debugger & Performance Analyzer, the Monitor Mode Debugging technology, the J-Link RDI / RDDI license, and the license pack for the RDI / RDDI interface.


As a multi-platform solution, J-Link BASE comes with the setup and control software for Linux, macOS and Windows. Software and firmware updates are included. Similarly, use on all currently supported target devices, and any that will be added, is also included.

Technical specifications

Supported OSMicrosoft Windows (x86/x64), Linux (x86/x64/Arm), macOS (x86/Apple Silicon)
Electromagnetic compatibility (EMC)EN 55022, EN 55024
Operating temperature+5°C … +60°C
Storage temperature-20°C … +65 °C
Relative humidity (non-condensing)Max. 90% rH
Size of J-Link BASE Classic (without cables)100mm x 53mm x 27mm
Weight of J-Link BASE Classic (without cables)70g
Size of J-Link BASE Compact (without cables)46mm x 46mm x 17mm
Weight of J-Link BASE Compact (without cables)20g
Available interfaces
USB interface (J-Link BASE Classic)USB 2.0 (Hi-Speed); USB Type B
USB interface (J-Link BASE Compact)USB 2.0 (Hi-Speed); Micro USB
Target interfaceJTAG/SWD 20-pin (adapters available)
JTAG/SWD interface, electrical
Power supplyUSB-powered Max. 50mA + Target Supply current.
Target interface voltage (VIF)1.2V … 5V
Current drawn from target voltage sense pin (VTRef)< 25µA
Target supply voltage5V (derived from USB voltage)
Target supply currentMax. 300mA
Reset typeOpen drain. Can be pulled low or tristated
Reset low level output voltageVOL <= 10% of VIF
For the whole target voltage range (1.2V <= VIF <= 5V)
LOW level input voltage (VIL)VIL <= 40% of VIF
HIGH level input voltage (VIH)VIH >= 60% of VIF
For 1.2V >= VIF <= 3.6V
LOW level output voltage (VOL) with a load of 10 kOhmVOL <= 10% of VIF
HIGH level output voltage (VOH) with a load of 10 kOhmVOH >= 90% of VIF
For 3.6 <= VIF <= 5V
LOW level output voltage (VOL) with a load of 10 kOhmVOL <= 20% of VIF
HIGH level output voltage (VOH) with a load of 10 kOhmVOH >= 80% of VIF
JTAG/SWD interface, timing
Target interface speedMax. 50 MHz
SWO sampling frequencyMax. 30 MHz
Data input rise time (Trdi)Trdi <= 20ns
Data input fall time (Tfdi)Tfdi <= 20ns
Data output rise time (Trdo)Trdo <= 10ns
Data output fall time (Tfdo)Tfdo <= 10ns
Clock rise time (Trc)Trc <= 3ns
Clock fall time (Tfc)Trc <= 3ns

Assembly dimensions

The compact variant of the J-Link PLUS is designed to mount securely and unobtrusively into development or end user equipment. The small size and two mounting holes enable placing the J-Link PLUS Compact into existing equipment housings or to reserve space for direct-to-PCB mounting.

Typical applications are test fixtures that are used to automate firmware verification during development, or long-term test setups. It also can be used for integrated firmware reflash or service purposes inside end equipment, minimizing the number of tools that service technicians must carry around.

J-Link Plus Compact

Explosion view of the J-Link BASE Compact

J-Link Plus Compact Dimensions

Assembly dimensions of the J-Link BASE Compact

Package content

J-Link BASE Classic

J-Link Base Classic
USB Cable
20Pin Target Ribbon

J-Link BASE Classic

USB cable

20-pin, 0.1″ target ribbon cable

J-Link BASE Compact

J-Link Base Compact
micro USB Cable
20Pin Target Ribbon

J-Link BASE Compact

USB cable

20-pin, 0.1″ target ribbon cable