Feather M4 CAN won't enumerate, red RGB on bootloader start

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nazdreg
 
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Feather M4 CAN won't enumerate, red RGB on bootloader start

Post by nazdreg »

I have Feather M4 CAN Express that was accepting sketches and suddenly stopped showing up as a serial device. I was manually resetting the board to do some power-up power analysis on an attached circuit when I noticed it was no longer enumerating. Now only the pin 13 LED lights up ~2 seconds after power on.

I've had a similar issue before so manually started the bootloader (double press of the reset button), but on doing so the RGB LED stays red rather than changing to green as other Feather M4s do. The small pin 13 red LED also pulses rapidly.

Is there anyway to recover this Feather? I don't have an external programmer on hand.
Thanks.

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adafruit_support_carter
 
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Re: Feather M4 CAN won't enumerate, red RGB on bootloader start

Post by adafruit_support_carter »

Double check you USB cable. Verify it's not a charge only cable. Then try the bootloader test again. Getting red indicates the bootloader was not able to connect to the host's USB.

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nazdreg
 
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Re: Feather M4 CAN won't enumerate, red RGB on bootloader start

Post by nazdreg »

The cable is the one that was previously uploading code just fine, and works with any other uC i've tested since. Same story with other USB C cables i've tested, and other USB ports on my laptop.

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Re: Feather M4 CAN won't enumerate, red RGB on bootloader start

Post by adafruit_support_carter »

OK, so probably not as simple as a bad USB cable.
I was manually resetting the board to do some power-up power analysis on an attached circuit
What is the "attached circuit" mentioned here? Can you post a photo of the setup?

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nazdreg
 
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Re: Feather M4 CAN won't enumerate, red RGB on bootloader start

Post by nazdreg »

The relevant part of the circuit that we connected are attached. Only power and serial were connected to the load (A Cubemars AK80-9 motor).

The digital out to enable power to the load is isolated from the 48V external supply by the optoisolator. The grounds are tied together , and +5VD is generated from the 48V using an isolated DC-DC.

There is no optoisolator on the serial data lines from the Mux.
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