I have a Arduino Nano 33 BLE that I've been using for a while. I usually upload new programs to the board through USB with the board in a bootloader loop. The other day this stopped working. The board can successfully be put in the bootloader (slow pulsing light), however it does not appear as a TTY device on my computer. The last program I put on my device still works, and successfully outputs serial output (and I can even connect to the bluetooth module).

This leads me to believe my board is working, though I don't understand why I cannot upload via the bootloader. Interestingly the bootloader running makes the board pretty hot (hotter than my program running, is it in an infinite loop or something?).

I thought the bootloader might've been corrupted, so I re-uploaded the board's bootloader via a raspberry pi over OpenOCD (it's possible I did this incorrectly?). Now the device remains in the bootloader no matter what.

I'm wondering if it's possible I fried just the USB part of my board? is that likely? I did hook up the board to a wall adapter that is rated 12V @ 1.5A. The issue seemed to occur after this. Is the board able to handle 1.5A? Do I need to use an additional circuit to properly power the board off of this power adapter?

  • So I cannot even attempt to upload it, as the board is not available for selection. A ls /dev/tty.* results in no devices. Apr 13, 2022 at 14:03
  • If you put that 12V to Vin pin, it should be fine, to any other pin it means death.
    – KIIV
    Apr 13, 2022 at 14:44
  • @KIIV thanks! that's what I expected, I didn't see a max current for that pin, and assumed that shouldn't be a problem (it should just draw the amount it needs, no?) Apr 13, 2022 at 14:51
  • Yes, I did see that, the detail data sheet says the Vin feeds into a 3.3V power which has a max current of 1A. Is it possible I messed something up there? I have a new board on the way, my bigger concern is not also bricking that board, if I have indeed bricked my current board. Apr 13, 2022 at 16:25
  • I'd expect smoke to appear if an Arduino gets fried with 12V and that should most likely have killed the entire controller.
    – Sim Son
    Apr 13, 2022 at 16:48


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