The 74ACT161 is an advanced high-speed CMOS SYNCRONOUS PRESETTABLE COUNTER fabricated with sub-micron silicon gate and double-layer metal wiring C 2MOS tecnology. It is a 4 bit binary counter with Asynchronous Clear. The circuit have four fundamental modes of operation, in order of preference: synchronous reset, parallel load, count-up and hold. Four control inputs, (CLEAR), (LOAD), (PE) and (TE), determine the mode of operation as shown in the Truth Table. A LOW signal on CLEAR overrides counting and parallel loading and sets all outputs on LOW state. A LOW signal on LOAD overrides