[SOLVED] Tracing over SWD pins?

This site uses cookies. By continuing to browse this site, you are agreeing to our Cookie Policy.

  • [SOLVED] Tracing over SWD pins?

    I think I know the answer from the documentation I've read on the J-Trace but I want to be sure:

    Is it possible to do instruction tracing over just the minimum SWD connection? (SWDIO and SWDCLK). I have a project that's extremely limited on I/O and the trace pins and SWO pins are used for other purposes. Or do you absolutely have to have the trace pins (TRx and TCLK) in order to do instruction tracing?

  • Hi,

    For a reliable instruction trace, you need (besides SWCLK and SWDIO) also TCLK and TDATA 0-3 (TDATA0 may be sufficient for slower core speeds).
    The trace pins are there for a reason...

    Theoretically, you can also output the ETM (instruction trace) data over the SWO pin but it is easily overloaded with that data. SWO was mainly designed for printf-like output.


    BR
    Alex
    Please read the forum rules before posting.

    Keep in mind, this is *not* a support forum.
    Our engineers will try to answer your questions between their projects if possible but this can be delayed by longer periods of time.
    Should you be entitled to support you can contact us via our support system: segger.com/ticket/
    Or you can contact us via e-mail.