State Machines#

Hardware follows a plan.

Combine storage with combinational logic that decides the next state from the current state and the inputs, and the result is a finite state machine — the general form of every sequential circuit. A counter is a trivial state machine; a bus controller or a traffic-light sequencer is a deliberate one. The whole discipline is choosing the states, the transitions, and the encoding so the machine does what is intended and nothing dangerous when it doesn’t.

Sections#

• What Is a State Machine? — State, transition, and the next-state/output structure common to all of them.
• Moore vs. Mealy — Whether outputs depend on state alone or on state and input together.
• State Diagrams — Capturing behavior as states and labeled transitions before touching gates.
• State Encoding — Binary, Gray, and one-hot — and why the choice affects speed and safety.
• Sequencers — Counter- and shift-register-based machines that step through a fixed order.