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Explorer II
November 18, 2025
Solved

STM32 Nucleo-H723ZG PA11&PA12 not working? (GPIO & FDCAN)

  • November 18, 2025
  • 2 replies
  • 235 views

Dear Community,

I am using a Nucleo-H723ZG for my uni project and im running into issues with the PA11 & PA12 Pins.

I want to use them for FDCAN1 and I have verified that my code works.

 

No matter in what way i try to use these two pins the dont output.

if I switch to FDCAN2 with the same code and simply switch all instances of &hfdcan1 to &hfdcan2 i can read the signals with an scope and a can2usb adapter and get the right values.

 

I also tried to select just the mcu instead of the board because i read that sometimes USB_OTG messes with things but no luck.

Lastly i tried with another brand new Nucleo-H723ZG but also here no output on PA11 & PA12 whatsoever.

Not even in GPIO-Mode.

 

Do I have to turn something specific of?

I attached the full project.

 

Kind regards

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

    Hello @NeverRest and welcome to the community;

    mALLEm_0-1763485439538.png

    PA11 & PA12 are used by the USB on the board.

    Meanwhile you can play with the solder bridges according to the board schematic:

    To remove SB21 and SB22 to disconnect these IOs from the USB hardware part:

    mALLEm_1-1763485582523.png

    and solder SB16 and SB17 to connect them to CN12 connector: 

    mALLEm_3-1763485735913.png

     

    2 replies

    mƎALLEmAnswer
    Technical Moderator
    November 18, 2025

    Hello @NeverRest and welcome to the community;

    mALLEm_0-1763485439538.png

    PA11 & PA12 are used by the USB on the board.

    Meanwhile you can play with the solder bridges according to the board schematic:

    To remove SB21 and SB22 to disconnect these IOs from the USB hardware part:

    mALLEm_1-1763485582523.png

    and solder SB16 and SB17 to connect them to CN12 connector: 

    mALLEm_3-1763485735913.png

     

    NeverRestAuthor
    Explorer II
    November 18, 2025

    First of all thank you very much for your quick & detailed answer.

    I have just one question.

    The Nucleo board has two usb ports.

    Which of these two does this affect and will this affect my abillity to flash code to the board via usb?

     

    Kind regards

    Super User
    November 18, 2025

    It affects the USER USB port. It does not affect your ability to flash and debug the chip with ST-Link.

    NeverRestAuthor
    Explorer II
    November 18, 2025

    Okay thank you for the clarification.

    You two guys are my heroes.