Hello Everyone,
I am currently working with the FRDM-MCXA156 development board and have been facing an issue with SWO (Serial Wire Output) while debugging.
Although the application debugs successfully, I am unable to receive any data in the SWO Trace windows, including:
- SWO Data
- SWO Profile
- SWO Interrupt Trace
- SWO ITM Console
To troubleshoot the issue, I have already verified the following:
- The SWO pin has been correctly configured using Config Tools.
- The TRACE clock is enabled and configured to 96 MHz, matching the MCU core clock (MCXA156 runs at 96 MHz).
- The project is being debugged using LinkServer with the on-board MCU-Link probe.
Despite these configurations, all the SWO trace windows remain empty during debugging.
For reference, I have attached screenshots of the SWO Trace Configuration, SWO Data, SWO Profile, and other windows, along with the relevant project configuration.
I would greatly appreciate any guidance or suggestions on what might be causing this issue or if there are any additional configuration steps required to enable SWO trace on the FRDM-MCXA156.
Thank you for your time and assistance.
#swo #frdm-mcxa156
With respect to previous thread,
The screenshot of SWO enable configuration and clocks are attached below.
Thanks
Hello @sidsal
Thank you.
BR
Alice
Thank you for pointing this out @Alice_Yang . I checked the FRDM-MCXA156 schematic and confirmed that R36, which connects the P0_2/SWO signal to the onboard MCU-Link debugger, is marked as DNP.
I also noticed that on the FRDM-MCXN947, the equivalent SWO connection (R130) is populated with a 0 Ω resistor. Could you please confirm whether R36 on the FRDM-MCXA156 should also be populated with a 0 Ω resistor to enable SWO tracing through the onboard MCU-Link debugger?
Additionally, could you please clarify why R36 is left unpopulated (DNP) by default on the FRDM-MCXA156? Is there a specific board-design reason or limitation that requires it to remain unpopulated? So I cannot use SWO feature?
Thank you for your help.
Hello @sidsal
" Could you please confirm whether R36 on the FRDM-MCXA156 should also be populated with a 0 Ω resistor to enable SWO tracing through the onboard MCU-Link debugger?"
->>Yes. If you want to use the SWO function, you need to install a 0 Ω resistor or solder the connection accordingly.
“Additionally, could you please clarify why R36 is left unpopulated (DNP) by default on the FRDM-MCXA156? ”
->>I think this is because not all users require the SWO function, so the 0 Ω resistor is not populated by default.
Thank you.
BR
Alice
Thank you for your support @Alice_Yang .