Finite State Machines (FSMs) are a fundamental concept in computer science and are widely used in software development, hardware design, and other fields. They provide a way to model systems that can exist in a finite number of states and change from one state to another in response to inputs.

Basic Concepts

  • State: A state represents a condition or mode of the system.
  • Input: An input is an event or signal that can cause the system to change state.
  • Transition: A transition is the change from one state to another in response to an input.
  • State Diagram: A state diagram is a graphical representation of the states, transitions, and inputs of an FSM.

Types of FSMs

There are two main types of FSMs:

  • Mealy FSM: The output depends only on the current state and the input.
  • Moore FSM: The output depends only on the current state.

Applications

FSMs are used in a wide variety of applications, including:

  • User Interface Design: To model the behavior of buttons and other UI elements.
  • Control Systems: To model the behavior of robots, autonomous vehicles, and other systems.
  • Communication Protocols: To model the behavior of network protocols.

Example

Consider a simple traffic light system. The system can be in one of three states: red, yellow, or green. The transitions between these states are triggered by the passage of time and the detection of vehicles at the intersection.

  • Red State: The light is red, and the system waits for a certain amount of time.
  • Yellow State: The light turns yellow, and the system waits for a shorter amount of time.
  • Green State: The light turns green, and the system waits for a certain amount of time.

Traffic Light FSM

For more information on FSMs, you can read our detailed guide on Designing FSMs for User Interfaces.