Sometimes the built-in LED pulsates after an upload. It could be after a failed upload but I'm not entirely sure. What does this indicate? I haven't been able to find any information about it.

It doesn't blink like in the Bliky example. It pulsates.

The led is not controlled by a Sketch. Usually this happens after a failed upload, and the previous Sketch doesn't work anymore.

  • maybe it is the sketch that you loaded
    – jsotola
    Apr 27, 2021 at 15:56
  • @jsotola Usually it's after a failed update, and my best guess is that it is, but I haven't seen it documented anywhere. It's not in the sketch.
    – ivvi
    Apr 27, 2021 at 15:58
  • 1
    bootloader does it while active
    – Juraj
    Apr 27, 2021 at 16:38


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