SEGGER J-Trace Pro Cortex-M

J-Trace PRO for Cortex-M-based microcontrollers enables continuous streaming trace for code development and optimization.

SEGGER's J-Trace PRO can capture complete traces over long periods — thereby enabling the recording of infrequent, hard-to-reproduce bugs. This is particularly helpful when the program flow ‘runs off the rails’ and stops in a fault state.

It also supports extended trace features, such as Live Code Coverage (so engineers have visibility over which parts of the application code have been executed) and Live Code Profiling (providing visibility as to which instructions have been executed and how often, so hotspots can be addressed and optimization opportunities identified).

The J-Trace PRO Cortex-M provides support for Cortex-M-based microcontrollers. The SuperSpeed USB 3.0 interface of J-Trace PRO Cortex-M enables continuous streaming trace via USB with the full trace clock. Streaming in real time allows for data capture over long periods of time because there is no limit set on the amount of trace data. This gives you all the insight you need to develop and optimize your code.

Debug and trace connectors

J-Trace has two connectors. The pinout of the debug and trace connector is in the SEGGER knowledge base. The debug connector is for debug only and can be used with target adapters for J-Link.

Please note, that only one connector can be used at a time!

J-Trace connector layout



As a multi-platform solution, J-Trace PRO Cortex-M 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 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-Trace.


Up to 4 MB/s download speed make J-Trace PRO the fastest trace probe on the market.

Flash Breakpoints

The J-Trace PRO Cortex-M comes with an additional feature, called Unlimited Flash Breakpoints, which allows the user to set an unlimited number of breakpoints when debugging in flash memory.

 Ozone — The multi-platform debugger and performance analyzer

Ozone is a full-featured graphical debugger for embedded applications. It includes all well-known debug controls and information windows, and enables the best performance of J-Link debug probes and J-Trace trace probes. With Ozone it is possible to debug any embedded application on C/C++ source and assembly level. The Ozone Trace Tutorial allows developers to test the streaming and live analysis features of J-Trace PRO.

Instruction tracing

With streaming trace data users get deep insights into any application running on the target device whilst offering additional, powerful debug strategies to apply. It enables a far-reaching, yet complete, analysis of such issues, offering fast and efficient data analysis, ensuring higher productivity and also lowering development risks and costs.

Live Code Profiling

Code profiling details which instructions have been executed and how often. Users can address application runtime hotspots and identify opportunities to optimize them. It is all about measuring the execution time and frequency of functions, blocks and instructions and highlighting where computing time is spent. These profiles can later be exported using a tool like the Ozone debugger, for documentation and analysis purposes.

Live Code Coverage

Through Live Code Coverage, engineers gain fully accurate information about how much of a source line, block, function, or file has been executed on a target application. It is this information that makes it possible to detect code that hasn’t been covered by tests — even code that may be unreachable. This enables a fast and efficient way to improve the code or to create a suitable test suite for uncovered blocks.

Trace reference boards

Trace reference boards are optimal for simple and portable trace demos. These boards allow testing and verification of trace setups within minutes. They can also be used as a reference for custom hardware projects as the trace reference boards are optimized for best trace signal quality.

All trace reference boards come with an example project that runs out-of-the-box. For easy setup the boards can be powered using a J-Trace PRO V2 or later.



 J-Trace PRO Cortex-A/R/MJ-Trace PRO Cortex-MJ-Trace PRO RISC-V
Hardware features
Power supplyUSBUSBUSB
Download speed into RAM [1]4.0 MB/s4.0 MB/s4.0 MB/s
Max. CPU frequencyUnlimitedUnlimitedUnlimited
Max. TPIU frequency300 MHz300 MHz300 MHz
Max. trace clock frequency150 MHz150 MHz150 MHz
Max. SWO speed100 MHz100 MHz100 MHz
Max. target interface speed50 MHz50 MHz50 MHz
Host interfaces
Target interfaces
Trace interfaces
Buffer TraceVVV
Cortex-M ETM TraceVVX
Cortex-A ETM TraceVXX
Cortex-R ETM TraceVXX
Cortex-A PTM TraceVXX
SiFive Nexus Trace BTMXXV
Unlimited streaming trace + Live analysis [2]VVV
Software features
Flash Download VVV
GDB Server VVV
J-Flash VVV
Ozone VVV
Real-Time Transfer (RTT) VVV
Unlimited Flash Breakpoints VVV
Supported cores
Cortex-A5 D TXX
Cortex-A7  D TXX
Cortex-A8  D TXX
Cortex-A9 D TXX
Cortex-A12 D TXX
Cortex-A15 D TXX
Cortex-A17 D TXX
Cortex-M3D TDTX
Cortex-M4D TDTX
Cortex-M7D TDTX
Cortex-M33D TDTX
Cortex-R4D TXX
Cortex-R5 D TXX
Cortex-R8D TXX
SC000 (M0 secure)DDX
SC300 (M3 secure)DTDTX


V - Supported         D - Debug support: Run control, memory access, etc.          T - Pin trace supported        X - Not supported

[1]  The download speeds listed here are the peak download speeds that can be achieved by the particular J-Trace 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.

[2]  Unlimited streaming trace allows to transmit trace in real time to the PC. While traditional trace only allows to see and analyze the last xxx MB of trace data, with streaming trace it is possible to have all data available. This allows extended debugging features, such as code coverage or CPU load analysis based on a function basis.

  • Streaming trace probe with SuperSpeed USB3.0 interface and Gigabit Ethernet
  • Download speed up to 4 MB/s
  • Unlimited breakpoints in flash memory (Flash Breakpoints)
  • Use with Ozone and J-Flash
  • Real-time streaming at full System Clock
  • Fine-tune applications with Live Code Profiling
  • Instruction-level code coverage to satisfy regulatory requirements
  • Unlimited trace to isolate & identify hidden code defects
  • Supports Cortex-M targets
  • Full J-Link debug functionality
Supported OSMicrosoft 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
Size (without cables)123mm x 68mm x 30mm
Weight (without cables)(without cables) 120g
Available interfaces
Ethernet interfaceGigabit
USB interfaceUSB 3.0, SuperSpeed
Target interfaceJTAG/SWD 20-pin (14-pin adapter available)
JTAG/SWD + Trace 19-pin
JTAG/SWD interface, electrical
Power supplyUSB-powered (max. 400mA)
Target interface voltage (VIF)1.2V ... 5V
LOW level input voltage (VIL)VIL <= 40% of VIF
HIGH level input voltage (VIH)VIH >= 60% of VIF
JTAG/SWD interface, timing
Data input rise time (Trdi)Max. 20ns
Data input fall time (Tfdi)Max. 20ns
Data output rise time (Trdo)Max. 10ns
Data output fall time (Tfdo)Max. 10ns
Clock rise time (Trc)Max. 10ns
Clock fall time (Tfc)Max. 10ns
Trace interface, electrical
Power supplyUSB-powered (max. 400mA)
Target interface voltage (VIF)1.2V ... 5V
Voltage interface low pulse (VIL)Max. 40% of VIF
Voltage interface high pulse (VIH)Min. 60% of VIF
Trace interface
Max. trace clock frequency150 MHz
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