I had some very successful experiments with bit banging ISA on a Raspberry Pi 3 and 4 a while ago: https://github.com/polpo/pigus https://github.com/polpo/pigus

I had some very successful experiments with bit banging ISA on a Raspberry Pi 3 and 4 a while ago: https://github.com/polpo/pigus https://github.com/polpo/pigus I quickly moved over to a Raspberry Pi Pico because it's much better suited to such things. You need more than a couple I/O pins, though... to do real ISA (i.e., not LPC) right, you need more GPIOs than what the Pi gives you. But muxing the data/address lines is enough to give you back what you need.