J-Trace is a SEGGER debug and trace probe, specialized on live instruction tracing.
For the full feature set and best performance, it is recommended to use J-Trace in combination with the Ozone debugger.
For purchasing information and technical specification, please refer to the SEGGER homepage
- 1 General information about tracing
- 2 Available Trace features
- 3 Tested devices
- 4 Setting up Trace with J-Trace
- 5 Trouble shooting
General information about tracing
- General information about different trace types
- General information about Arm Coresight trace elements:
- Arm trace specification and timings
Available Trace features
Some trace features are only available for the J-Trace Pro series. For more information see below.
- J-Trace Pro supports all of the features listed above and additionally the following.
- Realtime/Streaming Trace
- Live code coverage
- Live code profiling
- Trace to file
- Trace automation with Ozone
The tested devices page on the SEGGER homepage contains a variety of different devices, that trace support has been tested with. For these devices example projects are available, including J-Link script files containing the required (pin) init. This is usually the best starting point if you want to trace a device, as it provides an out of the box experience.
Together with the J-Trace Pro, a trace reference board is shipped. For this board, a trace tutorial project is available on the SEGGER homepage.
Setting up Trace with J-Trace
If no example project is available for a specific device, and example project can be request via the official SEGGER Technical support. Otherwise, support can also be added manually which is explained below.
Pinout / Trace debug interface
Usually, devices provide multiple trace pin combinations to use trace with. This also means, that the pins have to be initialized before tracing can work.
The trace pinout (19-pin) used by J-Trace can be used with JTAG and SWD:
The pins, clocks, etc. required for tracing can be initialized either via the device application, or via a J-Link Script file. Using a J-Link script file is generally recommended, as otherwise the init section of the code will not be traced when initializing trace from the target application. Another benefit is that by using a J-Link Script file you guarantee that not debug code gets overlooked and accidently stays in your final product code.
Setting up Trace with Ozone
Setting up Trace with different IDEs
- Arm trace technical specification
- Trace board design recommendations
- Debug setup considerations when tracing
In this section multiple trouble shooting articles are referenced.
- Adjusting trace timings and general troubleshooting
- Debug & Trace with RAM Functions / reading into trace cache
- Handling J-Trace overflow errors
- Tracing modified code
- J-Trace driver issue (driver could not be started)
- USB driver not found / J-Trace detected as HP printer BIDI