2025-06-03 2:48 AM
Good morning,
I would like to request support regarding the programming and debugging of the STM32U031C8U6 microcontroller. It is mounted on a custom-designed board, and I am experiencing issues connecting to the microcontroller via SWD for programming and/or debugging using an ST-LinkV3 updated to the latest version (V3.J16.M8.B5.S1), with STM32CubeProgrammer and STM32CubeIDE. The microcontroller is never detected.
Note: With the ST-LinkV2 programmer, I am able to perform both programming and debugging without issues using the same software tools.
Many thanks in advance to anyone who can help me!
Solved! Go to Solution.
2025-06-03 6:14 AM
Thank you all,
I found the problem!!. Basically, if I use the JTAG20 header on the V2 and connect only the SWD pins, it works correctly. However, if I connect the same pins on the V3, it doesn’t work. Instead, it works when I connect the board using the SWD header pins.
I thought they were the same thing, but clearly I was wrong.
2025-06-03 2:54 AM
Have you connected the target voltage pin? ST-LinkV3 needs it.
2025-06-03 4:50 AM
Hello @MaxBrt and welcome to the community,
You need to share the schematic so others can help you efficiently.
Thank you
2025-06-03 4:57 AM
Welcome to the forum.
For best results, please see How to write your question to maximize your chances to find a solution.
@MaxBrt wrote:It is mounted on a custom-designed board,
So, as @mƎALLEm said, you need to supply full details of the board - in particular, the schematics.
Also show how the ST-Link is connected.
Some good, clear photos of your setup would also help.
Some Knowledge Base articles on debugger connection issues:
How to solve connection errors when connecting and programming the STM32 target board.
How to solve debugger connection issues
2025-06-03 6:07 AM
Show a picture of the setup, showing connecting between chip and programmer.
Ensure the board is powered. The programmer generally does not provide this.
Show a picture of STM32CubeProgrammer screen when it fails to detect the chip.
2025-06-03 6:14 AM
Thank you all,
I found the problem!!. Basically, if I use the JTAG20 header on the V2 and connect only the SWD pins, it works correctly. However, if I connect the same pins on the V3, it doesn’t work. Instead, it works when I connect the board using the SWD header pins.
I thought they were the same thing, but clearly I was wrong.
2025-06-03 6:17 AM
@MaxBrt wrote:I found the problem!!.
Great - thanks for feeding back.
Now please mark your post as the solution:
https://community.st.com/t5/community-guidelines/help-others-to-solve-their-issues/ta-p/575256