[chillingeffect]

I love it. Ive been reviving a stack of 4 c64s i got untested for $285. I noticed CIA chip replacements cost 40-45 and was wondering if an Rpi pico could replace it! I'll bet they combined two CIAs into one. I'm curious if they repeat the typical 24+ pin bus (16 addr, 8 data, plus more control lines).

[robinsonb5]

Not directly - you'd need level shifters to handle the 5V signals in the C64. (The RP2040 isn't "officially" 5V tolerant - there are certain circumstances where you can get away with wiring some its inputs directly to 5V logic, but those circumstances exclude bidirectional IO.)

[croemer]

Do CIA chip replacements come with a backdoor? </s>

[genewitch]

Yes, via the frame buffer interface pins