BLS COIN M0 - added supporting libraries so frozen neopixel works

[bradanlane]

This pull request is to add the neopixel_write and pixelbuf modules to the build for the COIN_M0. This is to enable 'out of the box' support for neopixels ~(which is already a frozen library for the board)_.

A full new CircuitPython 10 build environment was used to build and deploy. The contents of boot_out.txt are provided for reference:

Adafruit CircuitPython 10.0.0-beta.2-23-g4b2624a27b on 2025-08-29; Bradán Lane STUDIO Coin M0 with samd21g18
Board ID:bradanlanestudio_coin_m0
UID:296759F1464A305020312E46273314FF

[dhalbert]

@bradanlane

This board has external flash, so it's more like Feather M0 Express than, say, Trinket M0. So there is a lot more room, and you don't need to turn off so many modules.

I would suggest using something like the feather_m0_express/mpconfigboard.mk. You can turn off modules that are useless, but I'd leave LONGINT_IMPL = MPZ so you can have longints. And don't set CIRCUITPY_FULL_BUILD = 0. Just remove it and it will default to CIRCUITPY_FULL_BUILD = 1. Then you can turn off modules that are useless to make room for any frozen libraries.

With CIRCUITPY_FULL_BUILD = 1, CIRCUITPY_PIXELBUF will default to on. CIRCUITPY_NEOPIXEL_WRITE always defaults to 1. I think your issue was lack of pixelbuf, not neopixel_write.

[bradanlane]

The coin m0 was originally based off the Itsy Bitsy (about a year ago).

One reason so much is turned off is the coin m0 is a "feature" board and has no exposed IO pins. It really only has SAMD21 analog audio to an onboard piezo, 3 touch pads, and 9 neopixels.

I am reticent to make too many changes as it should then be fully tested again.

I will change CIRCUITPY_FULL_BUILD = 1

[dhalbert]

Looks fine now!

After you make changes and they build, click the circular arrows next to my username so I'll get a request to re-review. Then I'll get a ping about. Thanks.