CubeMX2, allow to use SWD without SWO

av500 · ‎2026-03-25

when you enable SWD in CubeMX2 it automatically blocks the SWO pin as well (tested using C531FBP6), but I only need SWCLK / SWDIO to debug. please add a way to disable the use of SWO.

Oussama_TROUDI · ‎2026-03-26

@Karl Yamashita

but here with attached screenshots you are resetting a reserved pin, not a fully configured one.
You can clearly see the difference in the Pinout legend:

Light‑green circle = Reserved pin
Dark‑green circle with check mark = Configured pin

and on your screenshot, PB3 (JTDO/TRACESWO) is shown with the “Reserved pin” color, meaning it’s only reserved for DEBUG_TRACESWO by the debug configuration.
When you click “Configure DEBUG”, you will see that SWD is not fully activated as a normal configured pin; it’s just reserved by the debug settings, and you can still reset it.

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av500 · ‎2026-03-26

yes, when you open the C652 NUCLEO board, the 3 SWD pins are reserved and can be reset, but once debug is configured, you cannot reset any of them...

Karl Yamashita · ‎2026-03-26

@av500 @Oussama_TROUDI

I see now, I didn't Activate the SWD. Because it was highlighted and labeled when the project was opened, I assumed it was enabled. I didn't look at the legend.

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Saket_Om · ‎2026-03-30

Hello @av500

Thank you for bringing this issue to our attention.

I reported this internally.

Internal ticket number: CDM0061153

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