7.2: Gates, truth tables, and logic equations

Asserted signal

A signal that is (logically) true, or 1

Deasserted signal

A signal that is (logically) false, or 0.

Combinational logic

A logic system whose blocks do not contain memory and hence compute the same output given the same input.

Sequential logic

A group of logic elements that contain memory and hence whose value depends on the input as well as the current contents of the memory.

Gate

A device that implements basic logic functions, such as AND or OR.

AND gate

OR gate

Inverter

NOR gate

NAND gate