Replacing a 6502 by a 6809 (or a 6309) is difficult but it can be done, for example: https://anachrocomputer.github.io/sixadapt.htm https://anachrocomputer.git

Replacing a 6502 by a 6809 (or a 6309) is difficult but it can be done, for example: https://anachrocomputer.github.io/sixadapt.htm https://anachrocomputer.github.io/sixadapt.htm