[SOLVED] SAMD21 JLink hot-plug/attach does not work when target is in power-down

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  • [SOLVED] SAMD21 JLink hot-plug/attach does not work when target is in power-down

    Dear Segger,

    I am using Jlink Plus to hot-plug/attach to my running target (SAMD21) which works basically fine. This great.

    Now I encounted problems when the firmware is longer in power-down.

    I do not have checked the edge timing when is still works, I have an firmware with realizes two power-down timings and can reproduce the issue. When the mcu wakes every 10ms hot-attach works, when doing the wakes only every 2.5 s it fails. Then the reset line is asserted automatically by Jlink. I am using Ozone for testing. Seem that there is a timeout which leads to the hw reset. How to changes this behaviour?


  • Hello Stefan,

    Thank you for your inquiry.
    When using sleep modes the debug logic must still be available for J-Link to access the device reliably during sleep.
    If that is not the case (depends on how the target device has implemented it) J-Link will assume that it has lost connection and will try to reconnect to the target device.
    So from J-Link side there is not much we can do if the target device does not support debugging while in sleep modes.

    Best regards,
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