such as a Motorola 68000. If the address lines changed while chip select was low (inactive) but the ϕ2 clock input was high (active), register contents could be changed despite the fact that the chip was not selected. This was fixed in some but not all of the CMOS versions. References External links MOS 6522 VIA preliminary datasheet (1977) MOS 6522 VIA die shots WDC W65C22 description MOS Technology integrated circuits Input/output integrated circuits