NOR Gate (Verilog)

Synopsis

All logic gates can be simplified to a NOR Gate. This is a demonstration of a NOR Gate in Verilog

Notes

I am not an expert, but I discourage using truth tables in Verilog as doing so may defeat optimizations that the compiler may otherwise perform. This is only included as a reference, not as a best practice.

Compilation

iverilog -o Nor_tb.vvp Nor_tb.v
vvp Nor_tb.vvp
gtkwave Nor_tb.vcd

Code Nor.v by assignment

1 module Nor(Q,A,B);
2 	output Q;
3 	input A,B;
4 	assign Q = ~(A | B);
5 	endmodule

Code Nor.v by truth table

 1 primitive Nor(Q, A, B);
 2 	output Q;
 3 	input A,B;
 4 	table
 5 		0 0 : 1;
 6 		0 1 : 0;
 7 		1 0 : 0;
 8 		1 1 : 0;
 9 		x ? : 0;
10 		? x : 0;
11 	endtable
12 endprimitive

Code Nor_tb.v test bench

 1 `timescale 1ns/1ns
 2 `include "Nor.v"
 3 
 4 module Nor_tb;
 5 
 6 reg A;
 7 reg B;
 8 wire Q;
 9 
10 Nor uut(Q,A,B);
11 
12 initial begin
13 	$dumpfile("Nor_tb.vcd");
14 	$dumpvars(0,Nor_tb);
15 
16 A = 0;
17 B = 0;
18 #10;
19 A = 1;
20 #10;
21 B = 1;
22 #10;
23 A = 0;
24 #10;
25 
26 $display("Test Complete!");
27 end
28 endmodule

Pictures

GTKWave Signals of a NOR Gate