The MC74HCT259A is identical in pinout to the LS259. The device inputs are compatible with standard CMOS and LSTTL outputs. The HCT259A has four modes of operation as shown in the mode selection table. In the addressable latch mode, the data on Data In is written into the addressed latch. The addressed latch follows the data input with all nonaddressed latches remaining in their previous states. In the memory mode, all latches remain in their previous state and are unaffected by the Data or Address inputs.