NOR Gate

An NOR gate is a fundamental binary logic gate with N inputs and one output. The output is 1 if all inputs are 0.

The following truth table gives the specification for a two input NOR gate with output X:

A	B	X
0	0	1
0	1	0
1	0	0
1	1	0

The schematic form of the NOR gate is:

Below is a Verilog structural model for the NOR gate. In the code, the first argument to nor is the gate output, the other arguments are inputs.

	    
module nor_gate(X, A, B);
   output X;
   input  A;
   input  B;

   nor(X, A, B);
endmodule
	    
	  

References

Mano, M. Morris, and Kime, Charles R. Logic and Computer Design Fundamentals. 2nd Edition. Prentice Hall, 2000.
Kleitz, W. Digital Microprocessor Fundamentals. 3rd Edition. Prentice Hall, 2000.