OR Gate

An OR gate is a fundamental binary logic gate with N inputs and one output. The output is 1 if any input is 1. The equivalent logical connective is disjunction.

The following truth table gives the specification for a two input OR gate with output X:

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

The schematic form of the OR gate is:

Below is a Verilog structural model for the OR gate. In the code, the first argument to or is the gate output, the other arguments are inputs.

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

   or(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.