Finite state machine

The state of the program is its memory. A finite state machine continuously computes the current state with the previous state based on a function.

In a Moore circuit, output only depends on the current state. This is visualized by existence of output on each state node in a state diagram.

In contrast, in a Mealy circuit, input is also wired into the output logic. This is visualized by existence of output on each edge in a state diagram.

A Moore machine is synchronous, whereas a Mealy machine is asynchronous. This is because the input is wired into a Mealy machine's output combinational circuit along with the current state.