April 30, 2022 Arduino

Timer Interrupt

#include <Arduino.h>

#define ledPin 13

void setup() {
  pinMode(ledPin, OUTPUT);

  // initialize timer1 
  noInterrupts();           // disable all interrupts
  TCCR1A = 0;
  TCCR1B = 0;
  TCNT1  = 0;

  OCR1A = 31250;            // compare match register 16MHz/256/2Hz
  TCCR1B |= (1 << WGM12);   // CTC mode
  TCCR1B |= (1 << CS12);    // 256 prescaler 
  TIMSK1 |= (1 << OCIE1A);  // enable timer compare interrupt
  interrupts();             // enable all interrupts
}


ISR(TIMER1_COMPA_vect){                             // timer compare interrupt service routine
  digitalWrite(ledPin, digitalRead(ledPin) ^ 1);    // toggle LED pin
}

void loop() {
  // your program here…
}