Why state machines are used in embedded in Embedded C - See It in Action

Why State Machines Are Used in Embedded Systems

📖 Scenario: Imagine you are building a simple traffic light controller for a small intersection. The traffic light changes from green to yellow to red and then back to green in a loop. To manage these changes clearly and safely, you use a state machine.

🎯 Goal: You will create a simple state machine in C that controls the traffic light states. This will help you understand why state machines are useful in embedded systems for managing different modes or states clearly and reliably.

📋 What You'll Learn

Create an enum to represent the traffic light states

Create a variable to hold the current state

Write a function to move to the next state

Print the current state to show the state machine working

💡 Why This Matters

🌍 Real World

State machines are used in embedded systems like traffic lights, washing machines, and elevators to control different modes and actions in a clear, predictable way.

💼 Career

Understanding state machines is important for embedded developers to write reliable and maintainable code that controls hardware behavior step-by-step.

1

Create the traffic light states

Create an enum called TrafficLightState with these exact states: RED, GREEN, and YELLOW.

Embedded C

// Your code here

Need a hint?

An enum lets you name states with words instead of numbers. This makes your code easier to read.

2

Create a variable for the current state

Create a variable called currentState of type TrafficLightState and set it to RED.

Embedded C

typedef enum {
    RED,
    GREEN,
    YELLOW
} TrafficLightState;

// Your code here

Need a hint?

This variable will remember which light is currently on.

3

Write a function to change to the next state

Write a function called nextState that changes currentState from RED to GREEN, from GREEN to YELLOW, and from YELLOW back to RED.

Embedded C

typedef enum {
    RED,
    GREEN,
    YELLOW
} TrafficLightState;

TrafficLightState currentState = RED;

// Your code here

Need a hint?

The switch statement helps you decide what the next state should be based on the current state.

4

Print the current state

Write a main function that calls nextState() three times and prints the currentState after each call. Use printf to print "RED", "GREEN", or "YELLOW" depending on the state.

Embedded C

typedef enum {
    RED,
    GREEN,
    YELLOW
} TrafficLightState;

TrafficLightState currentState = RED;

void nextState() {
    switch (currentState) {
        case RED:
            currentState = GREEN;
            break;
        case GREEN:
            currentState = YELLOW;
            break;
        case YELLOW:
            currentState = RED;
            break;
    }
}

// Your code here

Need a hint?

Use a loop to call nextState() and a switch to print the current state as text.