Hi everyone,
I’ve spent the last few hours troubleshooting SWO (Serial Wire Output) trace within VS Code. I know this is a recurring issue in the forums, and while ST employees have mentioned they are working on a native implementation, I wanted to share a solid workaround that is currently working for me.
It’s a bit tricky to set up the first time, but once you have your launch.json and OpenOCD paths configured correctly, it works great.
The steps are:
1. Install Cortex-Debug
1. Run & Debug - > Add Configuration -> Modify the launch.json file
2. launch.json:
{
"version": "0.2.0",
"configurations": [
{
"name": "Cortex Debug",
"type": "cortex-debug",
"request": "launch",
"servertype": "openocd",
"serverpath": "C:/ST/STM32CubeIDE_2.0.0/STM32CubeIDE/plugins/com.st.stm32cube.ide.mcu.externaltools.openocd.win32_2.4.300.202509300731/tools/bin/openocd.exe",
"cwd": "${workspaceFolder}",
"executable": "${workspaceFolder}/build/Debug/project.elf",
"device": "STM32L471RETx",
"configFiles": [
"${workspaceFolder}/project.cfg",
],
"searchDir": [
"C:/ST/STM32CubeIDE_2.0.0/STM32CubeIDE/plugins/com.st.stm32cube.ide.mcu.debug.openocd_2.3.200.202510310951/resources/openocd/st_scripts"
],
"svdFile": "${workspaceFolder}/YOUR_MCU.svd",
"interface": "swd",
"runToEntryPoint": "main",
"armToolchainPath": "C:/Users/YourUser/AppData/Local/stm32cube/bundles/gnu-tools-for-stm32/14.3.1+st.2/bin",
"swoConfig": {
"source": "probe",
"enabled": true,
"swoFrequency": 2000000,
"cpuFrequency": 4000000, //Your CPU freq!!
"decoders": [
{
"type": "console",
"label":"Mcu-SWO-Trace",
"port": 0
}
]
},
"showDevDebugOutput": "raw"
},
]
}3. Get the .cfg and .svd files at:
- Cfg: Step 3.2.1
- .svd : https://community.st.com/t5/stm32-mcus-embedded-software/where-can-i-find-svd-file-for-stm32l431cct6-uc/td-p/103304
4. Enjoy your SWO:
5. If any issues arise please review DEBUG CONSOLE and TERMINAL(gdb-server) output for clues.
Hope this was helpful.
