One question that comes up pretty frequently among vintage computer enthusiasts is what to use as a MOS 6522 replacement. Commodore used this chip extensively, but so did others. There are suitable replacements in the form of second-source 65c22 chips, but not all of them work. Here’s what to use.
Commodore went out of business in 1994, and started winding down its chip production as early as 1992. But some of its designs were available through second sources, and the 6522 was one of them.