MOS Technology 6522

In addition to being manufactured by MOS Technology, the 6522 was second sourced by other companies including Rockwell and Synertek.

Video game platforms such as the Vectrex also used the 6522, as did the 1984 through 1989 Corvette digital dash cluster.

A high speed, CMOS version, the W65C22, is produced by the Western Design Center (WDC).

This feature of timer 1, combined with its ability to output to pin PB7, can be used to generate complex waveforms, for example pulse-width modulation signals, frequency sweeps, or bi-phase or FM-encoded serial bit streams.

The WDC W65C22S, in contrast, has a totem pole IRQ output that must be isolated from a wired-OR circuit by a Schottky diode, due to the fact that the totem pole output actively drives the IRQ pin high when the W65C22S is not interrupting.