MC74HC161A, MC74HC163A Presettable Counters HighPerformance SiliconGate CMOS The MC74HC161A and HC163A are identical in pinout to the MC74HC161A, MC74HC163A RESET 1 16 V CC RIPPLE FUNCTION TABLE 2 15 CLOCK CARRY OUT Inputs Output 3 14 P0 Q0 Clock Reset* Load Enable P Enable T Q 4 13 P1 Q1 L X X X Reset P2 5 12 Q2 H L X X Load Preset Data P3 6 11 Q3 H H H H Count H H L X No Count 7 10 ENABLE T ENABLE P H H X L No Count GND 8 9 LOAD *HC163A only. HC161A is an Asynchronous Reset Device H = high level, L = low level, X = dont care Figure 1. Pin Assignment 3 14 P0 Q0 4 13 PRESET BCD OR P1 Q1 DATA BINARY 5 12 P2 Q2 INPUTS OUTPUT 6 11 P3 Q3 RIPPLE 2 15 CLOCK CARRY OUT 1 RESET 9 PIN 16 = V CC LOAD PIN 8 = GND 7 ENABLE P COUNT ENABLES 10 ENABLE T Figure 2. Logic Diagram DEVICE/MODE TABLE Count Device Mode Reset Mode HC161A Binary Asynchronous HC163A Binary Synchronous