- #3 bit aynchornous ripple counter verilog code mod
- #3 bit aynchornous ripple counter verilog code serial
So QB will remain 0.QBQA = 01 after the first clock pulse.
#3 bit aynchornous ripple counter verilog code mod
If we use n flip flops to design the Johnson counter, it is known as 2n bit Johnson counter or Mod 2n Johnson counter.Īs soon as the first negative clock edge is applied, FF-A will toggle and QA will change from 0 to 1.But at the instant of application of negative clock edge, QA, JB = KB = 0. In this the inverted output of the last stage flip flop is connected to the input of first flip flop.
The JB and KB inputs are connected to QA. The JA and KA inputs of FF-A are tied to logic 1. If the “clock” pulses are applied to all the flip-flops in a counter simultaneously, then such a counter is called as synchronous counter. Hence it toggles to change QB from 1 to 0.QBQA = 00 after the fourth clock pulse. On the arrival of 4th negative clock edge, FF-A toggles again and QA becomes 1 from 0.This negative change in QA acts as clock pulse for FF-B. So QB does not change and continues to be equal to 1.QBQA = 11 after the third clock pulse. On the arrival of 3rd negative clock edge, FF-A toggles again and QA become 1 from 0.Since this is a positive going change, FF-B does not respond to it and remains inactive.
So it will also toggle, and QB will be 1.QBQA = 10 after the second clock pulse. On the arrival of second negative clock edge, FF-A toggles again and QA = 0.The change in QA acts as a negative clock edge for FF-B. There is no change in QB because FF-B is a negative edge triggered FF.QBQA = 01 after the first clock pulse. Since QA has changed from 0 to 1, it is treated as the positive clock edge by FF-B. Initially let both the FFs be in the reset stateĪs soon as the first negative clock edge is applied, FF-A will toggle and QA will be equal to 1.QA is connected to clock input of FF-B. It counts from 0 to 9.When the clock pulse advances to 10 the ports QB and QD become high and thus NAND gate’s output will become low which will reset all the flip flops.
#3 bit aynchornous ripple counter verilog code serial
Decade or BCD counter : A binary coded decimal (BCD) is a serial digital counter that counts ten digits.A 3-bit ripple counter can count up to 8 states.It counts down from 7 to 0. It counts from 0 to 7.ģ bit ripple down counter: It contains three flip flops. A 3-bit ripple counter can count up to 8 states. It is known as down counter as it counts down from 3 to 0.ģ bit ripple up counter: It contains three flip flops. A 2-bit ripple counter can count up to 4 states. 2 bit ripple down counter: It contains two flip flops.2 bit ripple up counter: It contains two flip flops.The flip-flop applied with external clock pulse act as LSB (Least Significant Bit) in the counting sequence.The flip-flop toggles the output either for every positive edge of clock signal or for negative edge of clock signal. It is known as ripple counter because of the way the clock pulse ripples its way through the flip-flops. The logic diagram of a 2-bit ripple up counter is shown in figure.īut you can use the JK flip-flop also with J and K connected permanently to logic 1.Įxternal clock is applied to the clock input of flip-flop A and QA output is applied to the clock input of the next flip-flop i.e. It is a group of flip-flops with a clock signal applied. Counter is the widest application of flip-flops. A digital circuit which is used for a counting pulses is known counter. This site uses Just the Docs, a documentation theme for Jekyll.Ĭounter is a sequential circuit.