STLINK-V3MINIE connecting SWO and VCP_TX pins

maple · ‎2025-05-06

I am making an adapter between 6‐pin target debug header and 14-pin STDC14 connector. The same cable will be used to program and debug both M0+ and M4 targets.

Can I hard-wire SWO (pin 8 ) and T_VCP_TX (pin 14) together? The idea is to have an option on target board to use either UART or SWO, whatever is available.

Will UART transmission affect SWD functionality by sending garbage (from SWV standpoint) to SWO pin?

update: sorry, posted this into wrong forum. can someone can move this into "dev tools", please?

update 2: I think I found an answer here: https://community.st.com/t5/stm32-mcus-boards-and-hardware/uart-signal-on-swo-pin-from-st-link-v2-3/m-p/742773/highlight/true#M22581

Sarra.S · ‎2025-05-13

Hello @maple, any updates on this matter? did the other thread solved your issue?

To give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.

maple · ‎2025-05-13

Hi Sarra,

The other thread provided info on electrical and protocol specifications, that seem to indicate the connection is possible. But it did not answer the main question, which is:

Can random UART data on SWO pin of STLINK-V3MINIE affect programming or debugging?

Or, put it another way, are the SWD and SWV functions completely independent? I want to be able to use the same cable with serial viewer for M4 targets, and with VCP for M0 targets.