Arduino Interrupts Guide

Introduction

Interrupts allow a microcontroller to respond immediately to important external or internal events.

Types of Interrupts

• Hardware Interrupts: Triggered by external signals on specific pins.
• Timer Interrupts: Triggered at fixed intervals based on timers.

Interrupt Modes

Mode	Description
RISING	Triggered when signal goes from LOW to HIGH
FALLING	Triggered when signal goes from HIGH to LOW
CHANGE	Triggered when signal changes state
LOW	Continuously triggers while signal is LOW

Example Code

const int interruptPin = 2;
volatile int counter = 0;

void setup() {
    pinMode(interruptPin, INPUT_PULLUP);
    Serial.begin(9600);
    attachInterrupt(digitalPinToInterrupt(interruptPin), countInterrupts, FALLING);
}

void loop() {
    Serial.println(counter);
    delay(1000);
}

void countInterrupts() {
    counter++;
}