[SOLVED] nRESET as Input/Output

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  • [SOLVED] nRESET as Input/Output

    Hi,

    In the J-Link user guide, the nRESET is listed as an I/O.

    I am just not clear what it means by I/O. I believe it is an output from the segger? Why is it listed as I/O?

    Furthermore, is this signal open drain or driven high?
  • Well, it is marked as an I/O because it is an I/O.
    J-Link can drive it LOW and J-Link can release it and read the pin level.
    The pin is open drain.

    Input makes sense because there may be a reset button on the target HW that may be pushed asynchronously to J-Link.

    On some MCUs like the NXP Kinetis series, the reset pin is also an output of the MCU where it can be driven LOW if the MCU is reset by software, running on it.
  • SEGGER - Alex wrote:

    Well, it is marked as an I/O because it is an I/O.
    J-Link can drive it LOW and J-Link can release it and read the pin level.
    The pin is open drain.

    Input makes sense because there may be a reset button on the target HW that may be pushed asynchronously to J-Link.

    On some MCUs like the NXP Kinetis series, the reset pin is also an output of the MCU where it can be driven LOW if the MCU is reset by software, running on it.

    Thank you, Alex! That makes perfect sense.
  • New

    Hi,
    As this inquiry is resolved, we will close this thread now.

    Best regards,
    Fabian
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