This is a bunch of misc. projects I've randomly done.  

m6502 is probably the most interesting subdir, it's a small logic-based 6502 emulator
that could be used to emulate an Apple I in a small (possibly even AVR) microcontroller.
(and it, among many others, could certainly run on a Pi Pico/STM32/RISC-V)

ancientARMs is a subproject which I may or may not break out someday with usage
notes for old ARM kit.  (First up is a NFS boot directory that gets a GUI mostly
working on an obscure Pace STB)