Add support for M4

[inventhouse]

Lack of support for M4 (specifically AT SAM D51) is blocking touchio support in CircuitPython: adafruit/circuitpython#268

I'd really like to have touch inputs on the Adafruit M4-based boards, but the data sheet basically just says "use qtouch"; how can I help?

[tannewt]

We'd love to have it too! A while ago I spent time trying to document the registers on the SAMD51 and port FreeTouch to it. I did enough to believe it was tough and not the same register layout as the SAMD21.

I think the easiest approach would be to use qtouch. However, if you like figuring out how something works, freetouch support would be awesome.

[inventhouse]

I'd love to try some reverse-engineering, but I don't know when I'll find the time.

Why doesn't touchio use qtouch on the M4 builds?

[tannewt]

Stubborn-ness mainly. We definitely could. It's just not the ideal.

[modelkayak]

Plus one, would definitely like support for this. Especially given the larger size of the M4.

Any hints on how one could help you all add support?

[DeamEyes]

Also interested in a solution to this. I've looked for any tutorials to add the atmel library, but haven't found anything step-by-step. Is it possible to add qtouch in an unofficial branch?

[wero1414]

Hello! we did the port to the SAML21 which clocks are kind of related to the SAMD51 in this fork if it helps to anybody to be looking at the SAMD51 port.

[davepruitt]

I am also very interested in support for the SAMD51. Is there any timeline on when this could happen?

[s-light]

I landed her from this question:
https://arduino.stackexchange.com/questions/43663/built-in-capacitive-touch-detection-with-samd21-development-board-arduino-zero#43694

LibrePTC is not update to include samd51 support
And i Aldi Süd not find any other lib..

Maybe as a work around (not tested yet) i can youse something like:
https://github.com/martin2250/ADCTouch

Are there any other libs in this direction that are known to work?