4 Bit Ring Counter Circuit Diagram

Examining the four bit binary count sequence another predictive pattern can be seen.

4 bit ring counter circuit diagram. Asic and fpga design to create finite state machines a binary counter would require an adder circuit which is substantially more complex than a ring counter and has higher propagation delay as the number of bits increases whereas the propagation delay of a ring counter will be nearly constant regardless of the number of bits. If we design a counter of five bit sequence it has total ten states. The values on the output lines represent a number in the binary or bcd number system. Ring counters are often used in hardware design e g.

A ring counter is a shift register a cascade connection of flip flops with the output of the last flip flop connected to the input of the first. The ring counter is also ideal in creating simple finite state machines. Whereas for the up down counter you can use multiplexers as switches as we saw in the design of the 3 bit synchronous up down counter. In this diagram we can see that the clock pulse clk is applied to all the flip flop simultaneously.

For the 4 bit synchronous down counter just connect the inverted outputs of the flip flops to the display in the circuit diagram of the up counter shown above. It is initialised such that only one of the flip flop output is 1 while the remander is 0. An n stage johnson counter will produce a modulus of 2 n stage n where n is the number of stages in flip flop. Therefore it is a synchronous counter.

In digital logic and computing a counter is a device which stores and sometimes displays the number of times a particular event or process has occurred often in relationship to a clock the most common type is a sequential digital logic circuit with an input line called the clock and multiple output lines. The ring counter is useful in hardware logic design such as application specific integrated circuit asic and field programmable gate array fpga. As the 4 bit ring counter 4 stages or 4 flip flops circulates the preset digit within one clock signal the output frequency of each flip flop is th of the main clock frequency. Of states in ring counter no.

Where a ring counter recirculated a single 1 the 4 stage johnson counter recirculates four 0s then four 1s for an 8 bit pattern then repeats. The state diagram of the 4 bit ring counter is shown in above picture. Here 4 bit register is used so 4 bit sequence has a total of 8 sequences. Following figure shows timing sequence for four bit johnson counter.

State diagram of ring counter. The diagram is a circuit of a 4 bit twisted ring counter which can functi. So for designing 4 bit ring counter we need 4 flip flop. Since we cannot clock the toggling of a bit based on the toggling of a previous bit in a synchronous counter circuit to do so would create a ripple effect we must find some other pattern in the counting sequence that can be used to trigger a bit toggle.