Skip to main content
Graduate II
June 4, 2025
Solved

STM32 Reset pin duration

  • June 4, 2025
  • 1 reply
  • 503 views

Hi,
We are working with the STM32G491 board and intend to drive the NRST pin using an external device. Could you please confirm the minimum low-level pulse duration on the NRST pin for it to be recognized as a valid reset by the MCU?

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

    350 ns

    TDK_0-1749041006257.png

     

    1 reply

    TDKAnswer
    Super User
    June 4, 2025

    350 ns

    TDK_0-1749041006257.png

     

    Graduate II
    June 4, 2025

    Hi @TDK ,
    The external device controls both the BOOT and NRST pins of the STM32G491 MCU. According to the datasheet, the minimum low-level pulse duration on the NRST pin required to trigger a reset is 350 ns. If I hold the BOOT pin high and apply a 1 ms low pulse on the NRST pin, will the MCU recognize it as a valid reset and enter bootloader mode?

    Super User
    June 4, 2025

    Yes, provided the BOOT0 pin state is not disabled in option bytes. See AN2606.