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Visitor II
May 6, 2025
Question

STLINK-V3MINIE connecting SWO and VCP_TX pins

  • May 6, 2025
  • 2 replies
  • 469 views

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 

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    2 replies

    ST Employee
    May 13, 2025

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

    mapleAuthor
    Visitor II
    May 13, 2025

    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.