Adafruit_Neopixel library: RP2040 support added

[Bodmer]

I have adapted the Adafruit_Neopixel library to support the RP2040 using the PIO features of the Pico/RP2040.

Download from here.

[earlephilhower]

Cool. I have never actually used a neopixel but they seem to be everywhere!

Can you include the uncompiled source for the PIO.h file, and also look at the PioProgram class in RP2040.h for a simple way of working w/in the existing Arduino setup. Tone.cpp or Servo.cpp shows how to use that class to work together w/others, and ensures only 1 copy is loaded in PIO memory.

You should also consider doing a PR on the docs/readme to include it in the list.

[Bodmer]

Done, apart from docs/readme.

[Bodmer]

Ah, had to revert, I was not testing the copy I thought I was!

[Bodmer]

Because the extension to the library follows the format of others (extern C) it cannot see the PioProgram class, so some restructuring will be needed.

[earlephilhower]

You can make the file .cpp and then just do extern "C" { ..... }; to allow C++ features but keep the C interface. We do that in many files where the C++ compiler is used for better error detection/etc.

[Bodmer]

OK, will do it that way.

[Bodmer]

Adafruit have accepted a pull request on the current version so the official Adafruit_Neopixel Github copy of the library now has RP2040/Pico support built in.

Todo: add PIO availability check.