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Graduate
March 11, 2025
Solved

STM32h755 Clock sync

  • March 11, 2025
  • 2 replies
  • 1321 views

Hi,

I am working on a product for one of my clients that included two MCUs (STM32h755) on the same board working together and he requested both MCUs to be run on the same time "same clock", to be synced together. could you please advise if it possible to add a clock generator IC to feed both MCUs same clock. if so, please suggest a component or a document that will help me with this design.

Thanks

    This topic has been closed for replies.
    Best answer by Andrew Neil

    If you use a clock generator, then it's just a digital signal that you apply to both microcontrollers.

    The microcontroller's datasheet will give the specifications of its input pin;

    The clock generator's datasheet will give the specifications of its output pin.

    Just make sure that those are compatible.

     +------+
     | |
    +---------+ +------->+ MCU1 |
    | | | | |
    | Clock | | +------+
    | Gen +---------->+
    | | | +------+
    +---------+ | | |
     +------->+ MCU2 |
     | |
     +------+

    2 replies

    Super User
    March 11, 2025

    One way would be to feed a clock signal to both using an XO. Another would be to generate the clock from one to send to the other using a TIM or MCO output.

    Graduate
    March 11, 2025

    Hi thanks for your answer
    would you recommend a clock generator to feed them both, or a design document to help.

    Super User
    March 14, 2025

    If you use a clock generator, then it's just a digital signal that you apply to both microcontrollers.

    The microcontroller's datasheet will give the specifications of its input pin;

    The clock generator's datasheet will give the specifications of its output pin.

    Just make sure that those are compatible.

     +------+
     | |
    +---------+ +------->+ MCU1 |
    | | | | |
    | Clock | | +------+
    | Gen +---------->+
    | | | +------+
    +---------+ | | |
     +------->+ MCU2 |
     | |
     +------+
    Super User
    March 14, 2025

    @baselimadt wrote:

    both MCUs to be run on the same time "same clock", to be synced together.


    Note that just running them on the same clock will not guarantee that they are synchronised!

     

    See: https://community.st.com/t5/stm32-mcus-products/synchronizing-the-clocks-of-two-stm32s/m-p/719808/highlight/true#M261443

    Graduate
    March 14, 2025

    Hi 
    I know this point, but for now I want to them to run on the same clock, since this is a requirement from the client.