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Hallowing M0 not registering as USB device
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Hallowing M0 not registering as USB device

by dpatterson on Tue Nov 05, 2019 2:07 pm

Hello.

For context, I'm on a Mac.

I've been merrily playing around with the All_seeing_skull code for the Hallowing M0 making various (mostly unsuccessful), changes.
All of a sudden, the Hallowing has stopped showing up as a USB device.
It doesn't show up ion the USB section of the System Report or under /dev/cu*.

I've tried pressed the Reset button and disconnecting/reconnecting. No joy.

Suggestions?

Thanks,
D.

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Re: Hallowing M0 not registering as USB device

by adafruit_support_carter on Tue Nov 05, 2019 2:31 pm

Have you tried also a double press of reset to get into bootloader mode?

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Re: Hallowing M0 not registering as USB device

by adafruit_support_bill on Tue Nov 05, 2019 3:07 pm

Also make sure that the switch on the bottom is in the ON position. (Got caught by that myself last night!)

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Re: Hallowing M0 not registering as USB device

by dpatterson on Wed Nov 06, 2019 12:04 pm

Double-press of the Reset button worked. Yay and Thanks!

Okay. Now can you please provide me with a detailed explanation of what just happened?
What is the difference between "normal" mode and bootloader mode?

A link to such a description will, of course, be just as good as long as there are plenty of details.

Just so you know, while new to the Arduino world, I am far from new to software development. I've been a professional developer for 40+ years and have worked on everything from accounting to database engines to device drivers. Hence the request for details.

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Re: Hallowing M0 not registering as USB device

by adafruit_support_carter on Wed Nov 06, 2019 1:04 pm

Now can you please provide me with a detailed explanation of what just happened?

What happened in your original post? This?
All of a sudden, the Hallowing has stopped showing up as a USB device.
It doesn't show up ion the USB section of the System Report or under /dev/cu*.

Not sure. This could have been something unrelated to the board and coming from your OS, USB cable, USB port, etc. Or it could have been something on the board - unknown hiccup in the firmware, etc.? There are various ways to recover. But being able to get back in to bootloader mode is always a good first step.

What is the difference between "normal" mode and bootloader mode?

There's a guide here that explains what a bootloader is and does:
https://learn.adafruit.com/bootloader-basics/overview
Think of normal mode as just not bootloader mode.

The SAMD boards, like the M0 on the Hallowing, have the ability to set protection on the bootloader code. This prevents your user code (firmware) from accidentally writing over it. This is very useful as it allows you to recover from all kinds of issues. For boards without this protection, if the bootloader code gets overwritten, then you are up a certain creek and recovery is much more difficult.

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Re: Hallowing M0 not registering as USB device

by dpatterson on Wed Nov 06, 2019 1:57 pm

Ah. Thanks for the link.
Why putting it onto bootloader mode solved the problem makes much more sense now.

Cheers!

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Please be positive and constructive with your questions and comments.