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Associate III
June 4, 2025
Solved

STM32 Reset pin duration

  • June 4, 2025
  • 3 replies
  • 608 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?

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Best answer by TDK

350 ns

TDK_0-1749041006257.png

 

3 replies

TDK
TDKBest answer
June 4, 2025

350 ns

TDK_0-1749041006257.png

 

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Associate III
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?

TDK
June 4, 2025

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

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