AIM:

To implement D flipflop using verilog and validating their functionality using their functional tables

SOFTWARE REQUIRED:

Quartus prime

THEORY

D Flip-Flop

D flip-flop operates with only positive clock transitions or negative clock transitions. Whereas, D latch operates with enable signal. That means, the output of D flip-flop is insensitive to the changes in the input, D except for active transition of the clock signal. The circuit diagram of D flip-flop is shown in the following figure.

This circuit has single input D and two outputs Qtt & Qtt’. The operation of D flip-flop is similar to D Latch. But, this flip-flop affects the outputs only when positive transition of the clock signal is applied instead of active enable. The following table shows the state table of D flip-flop.

Therefore, D flip-flop always Hold the information, which is available on data input, D of earlier positive transition of clock signal. From the above state table, we can directly write the next state equation as Qt+1t+1 = D

Next state of D flip-flop is always equal to data input, D for every positive transition of the clock signal. Hence, D flip-flops can be used in registers, shift registers and some of the counters.

Procedure

/* write all the steps invloved */

PROGRAM

/* Program for flipflops and verify its truth table in quartus using Verilog programming. Developed by:Vineela Shaik RegisterNumber:212223040243 */

module DFLIPFLOPNEGEDGE(D,Clock,Q,Qbar);
input D,Clock;
output reg Q,Qbar;
always @ (negedge Clock)// use negative edge clock for triggereing condition 
//compute D flipflop logic here
begin
 	Q=D;
Qbar=~D;
end
 endmodule

RTL LOGIC FOR FLIPFLOPS

TIMING DIGRAMS FOR FLIP FLOPS

RESULTS

The observation of the simulation results and confirm the successful execution of the program