Skip to main content
Associate II
September 8, 2025
Solved

SWO output not working with VSCode Cortex-Debug

  • September 8, 2025
  • 11 replies
  • 1626 views

Hello,

I am trying to get SWO output working in VSCode using the Cortex-Debug plugin (v1.12.1).
My setup:

  • Debugger: STLink V3-MINIE

  • MCU: STM32H747IIT6

  • IDE: VSCode with Cortex-Debug

  • GDB Server: OpenOCD

  • Debug config: Trace Asynchronous SW enabled in CubeMX

When I run the project in STM32CubeIDE, the SWO output works as expected.
However, in VSCode I don’t see any SWO output in the terminal.

I overrode the write function like this:

int _write(int file, char *ptr, int len) {
 int dataIdx;
 for (dataIdx = 0; dataIdx < len; dataIdx++) {
 ITM_SendChar(*ptr++);
 }
 return len;
}

My launch.json:

{
 "name": "CM7 SWO",
 "cwd": "${workspaceRoot}/CM7",
 "type": "cortex-debug",
 "executable": "build/Printf_CM7.elf",
 "request": "launch",
 "servertype": "openocd",
 "gdbPath": "/opt/ST/STM32CubeCLT_1.19.0/GNU-tools-for-STM32/bin/arm-none-eabi-gdb",
 "device": "STM32H747IITx",
 "svdFile": "/opt/ST/STM32CubeCLT_1.19.0/STMicroelectronics_CMSIS_SVD/STM32H747_CM7.svd",
 "configFiles": [
 "interface/stlink.cfg",
 "target/stm32h7x.cfg"
 ],
 "runToEntryPoint": "main",
 "preLaunchTask": "Build All Debug",
 "showDevDebugOutput": "raw",
 "swoConfig": {
 "enabled": true,
 "source": "socket",
 "swoFrequency": 2000000,
 "cpuFrequency": 480000000,
 "decoders": [
 {
 "port": 0,
 "type": "console"
 }
 ]
 }
}

When I launch debugging, I get this error message from the GDB server:

marus25.cortex-debug-1.12.1/support/openocd-helpers.tcl: 
Error: Could not find TPIU/SWO names. Perhaps it hasn't been created?

Does anyone know what I might be missing in the launch.json or OpenOCD configuration to get SWO working with Cortex-Debug and STLink V3-MINIE?

Thanks in advance!

Best regards 

OskarP.

Best answer by Cartu38 OpenDev
As far i can see no SWO support (yet at least)
Per release note semihosting is supported but not tracing in real at that
time

11 replies

Nawres GHARBI
ST Technical Moderator
September 15, 2025

@OskarP  Thanks for contributing to this forum—it’s the right place to get answers!
The best way to start is by installing STM32Cube for Visual Studio Code.

 

https://marketplace.visualstudio.com/items?itemName=stmicroelectronics.stm32-vscode-extension&ssr=false#overview

OskarPAuthor
Associate II
September 16, 2025

@Nawres GHARBI  Thanks for your reply, Nawres!
I already have STM32Cube for VS Code installed. The actual issue is that the cortex-debug extension, which STM32Cube also relies on, unfortunately does not support SWO when using the STLink server. Therefore, I switched to OpenOCD to get SWO capabilities.

Nawres GHARBI
ST Technical Moderator
September 16, 2025

could you share the extension version please ? seems you are using a very old one

OskarPAuthor
Associate II
September 16, 2025

@Nawres GHARBI Sure. I'm using the following versions:

- STM32Cube for Visual Studio Code Core Version 0.17.1

- STMCubeMX 6.15

- STMCubeCLT 1.19.0

Nawres GHARBI
ST Technical Moderator
September 23, 2025

Please update to the latest one on the Marketplace and switch to pre-release version

OskarPAuthor
Associate II
September 30, 2025

Hello Nawres,

sorry for the late reply. I have updated STM32Cube for Visual Studio Code to Core Version 1.0.3.

Could you please provide me with an example of a working launch configuration with SWO for the STM32H747IIT6?

Thank you very much for your help.

Best regards,
Oskar