Define the XOR GATE - Microprocessor?

The XOR GATE is a alike to an OR gate except for the instance when all the inputs are high. With a XOR gate when all the inputs are high the output will be low. In an OR gate the output would be high if all the inputs were high.

The output Q is true if either input A is true OR input B is true, however not when both of them are true: Q = (A AND NOT B) OR (B AND NOT A). This is like the OR gate but excluding both inputs being true. The output is true if inputs A and B are DIFFERENT. The Boolean and symbol expression for a 2-input XOR gate is shown below.

The truth table for a 2-input XOR gate is shown underneath.

The XOR gate is used often in mathematical circuits. An illustration of the use of a XOR gate is in the half-adder circuit. If any input is high the output of the half-adder needs to be high but if both inputs are high the output needs to be low and a carry out needs to be generated. The half-adder circuit is shown underneath.