#include <avr/io.h>
#include <avr/interrupt.h>
#include "mystd.h"
#include "utils.h"

#define PRESCALER 1024
#define TIMER_FREQ (F_CPU / PRESCALER)

// at a high level:
// Set the OC1A (PB1) pin as output
// set the TIMER1 mode to COMPARE (CTC)
// say to compare against OC1A
// set the value to be compated at X count
// say the presacler for the timer is 512
//
// all these information are on page ~140
void timer1_init(void) {
	// Set PB1 (OC1A) as output
	DDRB   |= _BV(PB1);

	// CTC mode (WGM12 = 1)
	TCCR1B |= _BV(WGM12);

	// Toggle OC1A on compare match (COM1B0 = 1)
	TCCR1A |= _BV(COM1A0);

	// Set compare values
	OCR1A	= TIMER_FREQ * 2;

	// Start timer with prescaler 1024 (CS12 | CS10)
	TCCR1B |= _BV(CS12) | _BV(CS10);
	
	// set OCR1A interrupt
	TIMSK1 |= _BV(OCIE1A);


	// HELLO NO `sei()` SO WE DO IT BY HAND
	SREG |= _BV(SREG_I);
}