Reading digital input pin state in Embedded C - Mini Project: Build & Apply

Reading digital input pin state

📖 Scenario: You are working with a microcontroller to read the state of a button connected to a digital input pin. The button can be pressed or released, and you want to detect its current state in your program.

🎯 Goal: Build a simple embedded C program that reads the digital input pin state of a button and prints whether the button is pressed or released.

📋 What You'll Learn

Create a variable to represent the digital input pin state.

Create a variable to represent the button pin number.

Read the digital input pin state using a function call.

Print the button state as 'Pressed' or 'Released'.

💡 Why This Matters

🌍 Real World

Reading digital input pins is essential in embedded systems to detect button presses, switches, or sensor signals.

💼 Career

Embedded software developers often need to read hardware pin states to interact with physical devices and control systems.

1

Setup button pin number variable

Create an integer variable called buttonPin and set it to 2 to represent the digital input pin number where the button is connected.

Embedded C

# Create an integer variable called buttonPin and set it to 2
# Your code here

Need a hint?

Use int buttonPin = 2; to store the pin number.

2

Create variable for button state

Create an integer variable called buttonState to store the digital input pin state of the button.

Embedded C

int buttonPin = 2;
// Create an integer variable called buttonState
// Your code here

Need a hint?

Declare int buttonState; without initializing it yet.

3

Read the digital input pin state

Use the function digitalRead(buttonPin) to read the button state and assign it to the variable buttonState.

Embedded C

int buttonPin = 2;
int buttonState;
// Read the digital input pin state into buttonState
// Your code here

Need a hint?

Use buttonState = digitalRead(buttonPin); to read the pin.

4

Print the button state

Use printf to print "Pressed" if buttonState equals 1, otherwise print "Released".

Embedded C

int buttonPin = 2;
int buttonState;
buttonState = digitalRead(buttonPin);
// Print "Pressed" if buttonState == 1 else print "Released"
// Your code here

Need a hint?

Use an if statement to check buttonState and print accordingly.