/*
 * Filename: Normal_Mode_0
 * Author: George Howard
 * Date: 1/05/2024
 * Description: PURPOSE – Get PORTA pin 7 to toggle every 0.5s.
 *              Mode of operation used: Mode 2 (CTC Mode).
 *               
 */

// Workings: 

#include <avr/io.h>
#include <HardwareSerial.h>
#include <avr/interrupt.h>
#include <avr/pgmspace.h>
#include <util/delay.h>

int main(void)
{
    Serial.begin(9600);
    cli();                                // Disable all interrupts

    DDRA = 0x80;                          // Set PORTA pin 7 as output
    PORTA = 0x00;

    OCR0A = 7812;
    
    TCCR0A = (1 << WGM01);                // Enable CTC mode
    TCCR0B = (1 << CS02) | (1 << CS00);   // Set prescaler to 1024

    TIMSK0 |= (1 << OCIE0A);              // Enable overflow interrupt

    sei();                                // Enable all interrupts

    while (1)
    {
        ;
    }
}

ISR(TIMER0_COMPA_vect)
{
    PORTA ^= 0x80;
}