The HCC40108B (extended temperature range) and HCF40108B (intermediate temperature range) are monolithic integrated circuits, available in 24 lead dual in line plastic or ceramic packageand plastic micropackage. The HCC/HCF40108B is a 4 X 4 multiport register containing four 4-bit register, write address decoder, two separate read address decoders, and two 3-state output buses. When the ENABLE input is low, the corresponding output bus is switched, independently of the clock, to a high impedance state. The high impedance third state provides the outputs with the capability of being connected to the bus lines in a bus organized system without the need for interface or pull-up components. When the WRITE ENABLE input is high, all data input lines are latched on the positive transition of the CLOCK and the data is entered into the word selected by the write address lines. When WRITE ENABLE is low, the CLOCK is inhibited and September 1988