J-Link PRO — The universal debug probe

J-Link PRO is SEGGER's versatile JTAG/SWD programming and debug probe with USB and Ethernet interfaces.

Overview

J-Link PRO is fully compatible with J-Link and can be used "out-of-the-box". J-Link PRO uses DHCP per default. The built-in web server makes manual configuration easy. Ethernet allows the use of the debug probe far away from the PC, over a hardwired or wireless network, in a development or production environment. It also makes download and debugging speeds higher and provides electrical isolation from the PC. The product also comes with all features of the regular J-Link.

Key features

Additional Ethernet interface
Download speed up to 4 MB/s
Unlimited breakpoints in flash memory (Flash Breakpoints)
Use with Ozone, RDI/RDDI and J-Flash
Additional LEDs for power and RESET indication
Comes with web interface for easy TCP/IP configuration (built-in webserver)
Built-in VCOM functionality
Supports a broad range of microcontrollers
Supports direct download into RAM and flash memory
Free software updates

Supported devices

The list of supported manufacturers, families and devices and SoCs includes tens of thousands of devices in hundreds of device families.

Device not listed? Please don’t hesitate to contact us.

Software

All software is included free of charge. It comes with licenses for all J-Link related SEGGER software products, such as J-Link Unlimited Flash Breakpoints, Ozone, RDI/RDDI, J-Flash, J-Link GDB Server, providing the optimum debugging solution for professional developers.

The J-Link Software and Documentation Package is available here:

Multi-platform

As a multi-platform solution, J-Link PRO 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.

J-Flash

J-Flash is a part of the J-Link Software and Documentation Package and allows the programming of the internal and external flash memory of a microcontroller-based embedded system via J-Link.

Learn more about J-Flash...

Speed

Up to 4 MB/s download speed make J-Link PRO the fastest debug probe on the market. Using TCP/IP instead of USB eliminates latencies from USB usage, resulting in higher debugging speed.

Learn more about flash programming speed...

Ethernet

J-Link PRO features a GBit-Ethernet interface as an alternative to USB connection.

Flexibility

Due to the Ethernet interface, long distances between the development PC and the target system are possible. You can set a default gateway for J-Link PRO making it also possible to use it in large intranets.

Safety (galvanic isolation)

Ethernet signal lines provide galvanic isolation of J-Link PRO (and so the target system) from the network and development PC.

Flash Breakpoints

The J-Link PRO 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.

Learn more about Unlimited Flash Breakpoints...

Ozone — The J-Link debugger

Ozone is the debugger for J-Link and J-Trace. It includes all well-known debug controls and information windows and makes use of the best performance of J-Link and J-Trace debug probes.

Standalone debugger

Ozone focuses on debugging. There are no compiler or project window distractions. All debug windows can be moved, resized and docked, to provide you with the workspace you need.

Ozone offers all well-known debug controls and information windows, and more. Instruction trace, power graph, live watches, and real-time terminal I/O further extend these capabilities.

Ozone: Debugging features (screen) — Debugging with Ozone

Performance analyzer

With J-Link's High-Speed Sampling technology, Ozone can sample and visualize an embedded system's variables over time. Checking values and flags in the debugger, while the target keeps running, is easy.

J-Link's power measurement features enable you to record the power consumption of your target device in a debug session. This is especially helpful when you are developing a low-power device and need to know how power consumption changes when you enable or disable certain components.

Ozone: Performance analysis features (screen) — Performance analysis with Ozone

Use case

Building a test farm with J-Link PRO

The J-Link PRO is ideally suited for the construction of a test farm. Also known as a board farm or a device farm, it consists of a number of boards or devices connected to a network via debug probes. It is an efficient way to share hardware, including with users in remote locations.

For any successful product, as the number of devices to be tested grows, a test farm becomes the only efficient way to ensure quality.

Using SEGGER’s Test Farm Power Adapter, the power supply of test devices can be controlled remotely. This enables automated reboot for the testing process as well as the ability to turn off devices not in use. In combination with the power-saving J-Link PRO, this makes it easy to build energy-efficient, large-scale test farms.

A J-Link PRO test farm can connect many of the same test devices or can connect completely different ones.

For more information, see SEGGER’s wiki article discussing "What is a test farm?".

Wireless debugging/telemetry

The J-Link PRO can be used for a wireless connection between monitoring/debugging PC and the target device. To achieve this, the J-Link PRO needs to be connected to a WiFi router or switch.

Learn more at: https://wiki.segger.com/Using_J-Link_via_WiFi#Via_WiFi_bridge

Media gallery

Product photos

SEGGER J-Link PRO: Debug probe (photo) — J-Link PRO

Videos

SEGGER J-Link Tutorials: The J-Link Configurator

Mar. 2022 | 5:24 min
J-Link — J-Link Configurator

SEGGER J-Link Tutorials: The J-Link Commander

Mar. 2022 | 7:48 min
J-Link — J-Link Commander

SEGGER J-Link Remote Server: Accessing a J-Link, J-Trace or Flasher remotely - anywhere in the world

Mar. 2019 | 4:35 min
J-Link Remote Server — Intro

SEGGER J-Link PRO: Performance analysis on RISC-V

Jan. 2022 | 4:02 min
J-Link — Performance analysis

SEGGER J-Link PRO: An introduction to Cortex-M faults and how SEGGER's Ozone debugger can help

Aug. 2020 | 5:22 min
J-Link & Ozone — Intro Cortex-M Faults

SEGGER J-Link PRO: Analyzing Cortex-M faults using SEGGER's Ozone debugger

Aug. 2020 | 7:30 min
J-Link & Ozone — Cortex-M Faults analysis

SEGGER BBC micro:bit J-Link upgrade: Step-by-step instructions

Aug. 2016 | 1:33 min
BBC micro:bit J-Link Upgrade — Intro

Technical specifications

General
Supported OS	Microsoft Windows (x86/x64), Linux (x86/x64/Arm), macOS (x86/Apple M1)
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
Mechanical
Size (without cables)	100mm x 53mm x 27mm
Weight (without cables)	73g
Available interfaces
Ethernet interface	100 Mbit/s
USB interface	USB 2.0 (Hi-Speed)
Target interface	JTAG/SWD 20-pin
JTAG/SWD interface, electrical
Target interface voltage (V_IF)	1.2V ... 5V
Current drawn from target voltage sense pin (VTRef)	< 25µA
Target supply voltage	5V (derived from USB voltage)
Target supply current	Max. 300mA
Reset type	Open drain. Can be pulled low or tristated
Reset low level output voltage	V_OL <= 10% of V_IF
For the whole target voltage range (1.2V <= V_IF <= 5V)
LOW level input voltage (V_IL)	V_IL <= 40% of V_IF
HIGH level input voltage (V_IH)	V_IH >= 60% of V_IF
For 1.2V >= V_IF <= 3.6V
LOW level output voltage (V_OL) with a load of 10 kOhm	V_OL <= 20% of V_IF
HIGH level output voltage (V_OH) with a load of 10 kOhm	V_OH >= 80% of V_IF
For 3.6 <= V_IF <= 5V
LOW level output voltage (V_OL) with a load of 10 kOhm	VOL <= 20% of V_IF
HIGH level output voltage (V_OH) with a load of 10 kOhm	VOH >= 80% of V_IF
JTAG/SWD interface, timing
Target interface speed	Max. 50 MHz
SWO sampling frequency	Max. 100 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
Analog power measurement interface
Sampling frequency	200 kHz
Resolution	50 uA

Package content

J-Link PRO: Ethernet cable white — Ethernet cable

J-Link PRO: 20-pin, 0.1" target ribbon cable — 20-pin, 0.1" target ribbon cable

FAQ

Q: Can I use J-Flash with J-Link PRO?

A: Yes. J-Link PRO comes with a license for J-Flash preinstalled on the probe itself. No license setup necessary, simply plug in J-Link PRO and start using J-Flash.

Q: What is the advantage of J-Link versus simple probes such as FTDI-based systems?

A: J-Link has numerous advantages: the actual J-Link software supplied by SEGGER (which enables use with common IDEs), the availability of Unlimited Flash Breakpoints for the debugging of software which runs in the flash of microcontrollers, it’s high speed and it’s simple, fast download into flash memory.

In contrast to most simple probes, J-Link supports adaptive clocking as well as SWD and SWO. It also functions more stably, since it is not just a dump USB to JTAG converter. Instead, it uses the intelligence of the built-in CPU which provides more robust communication. This is especially so in situations where the target CPU runs at low clock speeds.

Q: May I work with more than one J-Link at the same time, on the same machine?

A: Yes, you can connect an unlimited number of J-Links to your PC. No special configuration required; each J-Link is registered with its unique serial number on the PC. This enables you to have multiple J-Links connected at once.

Q: I have multiple Arm cores in my JTAG chain. How can I debug them (simultaneously) with J-Link?

A: That's simple: Two or more debuggers can use the same J-Link simultaneously. Multi-core debugging requires multiple debuggers or multiple instances of the same debugger. You need to tell your debugger which device in the scan chain you want to debug. Additional special settings are not required.

Q: Does J-Link support the Embedded Trace Buffer (ETB)?

A: Yes. J-Link supports ETB on Cortex-M3/M4/M7 and Cortex-A/R (if implemented by target device).

Q: Does J-Link support the Micro Trace Buffer (MTB)?

A: Yes.

Q: Does J-Link support the Embedded Trace Macrocell (ETM)?

A: No. ETM requires another connection to the ARM chip and a CPU with built-in ETM. ETM is supported by the J-Trace product family.

Q: What is the maximum voltage that can be handled by the galvanic isolation of the Ethernet?

A: The Ethernet data lines are isolated as required per IEEE 802.3 (test voltage 1500 Vrms for one minute). Note that this is NOT valid for the Ethernet shield that has a direct electrical contact to the USB shield and a resistive and capacitive coupling to probe GND. For an effective isolation, you need to use an unshielded twisted pair Ethernet cable.