See the following figure: Supplement: asynchronous counter (also known as ripple counter and traveling wave counter): The triggers that make up the asynchronous counter do not use the same clock source, and the triggers do not occur at the same time. Classification: Counter can be divided into synchronous counter and asynchronous counter according to the input mode of counting pulse.

The design of binary addition counting is as follows: Principle: 74LS74 is a double D flip-flop, that is, it has two D flip-flops, each D flip-flop is a counter, and then it can be connected in series to form an addition metal device.

The main idea of this design is clock frequency division and logical operation. It can also be understood as counter design and carry extraction.

Chip 74LS74 is selected, and the pin diagram is as follows. Description: 74LS74 is a double D flip-flop triggered by rising edge. The characteristic equation of D flip-flop is a design scheme: a counter consists of flip-flops. Flip-flops have two states: 0 and 1, so a single flip-flop can represent a binary number.

N D flip-flops with inverted output (D-NOT) are connected in series, the inverted output of each D flip-flop is connected to its own D input, and the output of the previous stage is used as the clock input signal of the next stage to form an N-bit binary asynchronous counter.