Counter introduction
Counting is one of the simplest basic operations. The counter is the logic circuit that realizes this kind of operation. In the digital system, the counter mainly counts the number of pulses to realize the functions of measurement, counting and control. At the same time, it also has the function of frequency division. The counter is composed of the basic counting unit and Some control gates are composed, and the counting unit is composed of a series of various flip-flops with the function of storing information. These flip-flops include RS flip-flops, T flip-flops, D flip-flops and JK flip-flops.