I’m looking to add support for ChipKIT to FastSPI_LED. I assume the place to start is with the latest RC4 release?
Yes. If the ChipKit environment implements the arduino methods for getting pin ports/bitmasks and setting input vs. output, then low performance bitbang’d SPI should, in theory, work out of the box (I have a chip kit here to start working with, but there’s other things on the table first before I get to it). There’s a class to implement to provide hardware SPI support - there’s AVR and teensy 3 ARM versions in there at the moment (I have a branch where I’m working on adding DUE as well as support for USARTS in SPI mode).
To do the clockline-less chips (e.g. TM1809, WS2811/12, etc…) as well as higher performance bit-banging, it gets a bit more fun. First, you’d need to implement a chip kit version of the pin classes in fastpin.h, as well as define/provide pin/port/bitmask mapping definitions. Then there’s writing the code for the clock-lineless chips. They have timing requirements that are measured in nano-seconds, which most likely means clock-cycle counting asm.
At least, this roughly outlines my plan for supporting chip kit when it comes around.