User Manual

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I'm having problems with COM ports and my Itsy/Feather 32u4/M0

Theres two COM ports you can have with the 32u4/M0, one is the user port and one is the bootloader port. They

are not the same COM port number!

When you upload a new user program it will come up with a user com port, particularly if you use Serial in your user

program.

If you crash your user program, or have a program that halts or otherwise fails, the user COM port can disappear.

When the user COM port disappears, Arduino will not be able to automatically start the bootloader and upload

new software.

So you will need to help it by performing the click-during upload procedure to re-start the bootloader, and upload

something that is known working like "Blink"