Essential Electronic Design Automation (EDA)

Logic

Logic is the circuitry used to compare, add, or subtract data words. A logical gate circuit typically has many inputs and just one output. Gate circuits are built of simple electrical switches. Logic is thus decision-making with switches.

See Figure C.1. A table next to each gate symbol shows the gate output for each set of inputs. The logic gate example shows gates with only two inputs, but gates may have three or more inputs.

Figure C.1. Logic Gates

Note that:

A logical AND gate's output is a “1” only if all inputs are “1”s.

The output of a logical OR gate is a “1” if any input is a “1”.

The output of an inverter gate is a “0” if the input ...