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Visitor II
June 4, 2025
Solved

RX/TX pin swapping

  • June 4, 2025
  • 3 replies
  • 461 views

We are using the STM32U575RIT6 device and performed a RX/TX swap on LPUART1, ports PC0 and PC1. When we enabled the Swap TX is properly transmitting out of PC0. But we are unable to read anything on the new RX pin PC1. 

Other than enabling the pin swapping what else would need to be changed? 

Are there any known issues with the SM32u5 pin swapping? 

    This topic has been closed for replies.
    Best answer by jrobinson2

    Solved,

    Thank you for confirming there are no issues with the device. We were able to solve the problem, which was caused by a level shifter, we had to adjust our boot sequence and now everything is working.

    3 replies

    Super User
    June 5, 2025

    There's unlikely to be issues with the chip related to this, especially since it works with the normal mapping. If there was a known issue, it would be listed in the errata sheet.

    STM32U575xx and STM32U585xx device errata - Errata sheet

    Super User
    June 6, 2025

    > we are unable to read anything on the new RX pin PC1

    What does this mean? What is the signal source and how do you "read" it, exactly?

    The basic test with UART is to connect Tx to Rx and write a very simple polled loopback test program, can you please do that?

    JW

    jrobinson2AuthorAnswer
    Visitor II
    June 6, 2025

    Solved,

    Thank you for confirming there are no issues with the device. We were able to solve the problem, which was caused by a level shifter, we had to adjust our boot sequence and now everything is working.