#include <avr/io.h>
#include <avr/interrupt.h>

unsigned int n_compare_matchs = 0;

ISR(TIMER2_COMPA_vect) {
    // Toggle D12 on every interrupt
    PORTB ^= (1 << PB4);  // Toggle D12 (pin 12 on the ATmega328P)

    // Increment the counter
    n_compare_matchs++;

    // Toggle D13 every 125 interrupts (1 second)
    if (n_compare_matchs >= 125) {
        PORTB ^= (1 << PB5);  // Toggle D13 (pin 13 on the ATmega328P)
        n_compare_matchs = 0; // Reset the counter for the next second
    }
}

int main() {
    // Set prescaler for Timer2 to 1024
    TCCR2B |= (1 << CS22) | (1 << CS21) | (1 << CS20);  // Prescaler 1024

    // Set Wave Generation mode to CTC (Clear Timer on Compare Match)
    TCCR2A = 0;  // Normal mode
    TCCR2B |= (1 << WGM22);  // Set CTC mode

    // Set OCR2A value to 124 for a 125 Hz interrupt rate
    OCR2A = 124;  // Compare match value for interrupt every 125 cycles

    // Enable Timer2 interrupt on compare match
    TIMSK2 |= (1 << OCIE2A);  // Enable compare match interrupt

    // Set D12 and D13 as outputs (PB4 and PB5 for ATmega328P)
    DDRB |= (1 << PB4) | (1 << PB5);  // Set D12 (PB4) and D13 (PB5) as outputs

    // Enable global interrupts
    sei();

    // Main loop does nothing, all work is done in ISR
    while (1) {
    }

    return 0;
}