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Visitor II
June 14, 2025
Question

uart 2 and uart 3 not transmitting in B-U585I-IOT02A

  • June 14, 2025
  • 2 replies
  • 456 views

HI 

  am using stm32 B-U585I-IOT02A  dev board in that the uart2 and uart3 are not transmitting the data but its receiving the data . I have set PH 13 and PH 15 high also . but Tx is not working only Rx working

my code

Screenshot 2025-06-14 210522.png

in this only hello2 getting in my serial terminal.

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    2 replies

    Graduate II
    June 14, 2025

    PH13 and PH15 do not have UART peripherals.

    KarlYamashita_0-1749934932521.png

    KarlYamashita_1-1749934992151.png

     

    Those pins are used to switch between 1 and 2 on the switcher 

    KarlYamashita_2-1749935351217.png

     

    Look at the schematic again, you'll see that USART2_TX is PA2 and USART3_TX is PD8

     

    shivssAuthor
    Visitor II
    June 15, 2025

    Hi @Karl Yamashita 

       PH 13 and 15 are not uart2 and 3 pins yes but need to use that for on board uart2 and 3 to work according to the user manual , used PA2 and PD8 only for Tx 

    Screenshot 2025-06-15 074028.png

    Graduate II
    June 15, 2025

    Sorry, I've misinterpreted your "set" to high, as in pulled-up to high for the Tx pins.

     

    If you are receiving on USAT3, then the switcher is configured correctly. So what are you transmitting to?

     

    Also, use strlen to send the correct amount of characters.

    HAL_UART_Transmit(&huart2, (uint8_t*)"hello\n", strlen("hello\n"), 100) 

     

    shivssAuthor
    Visitor II
    June 15, 2025

    Hi @Karl Yamashita 

      Thanks for the help