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/* speaker control, uses timer2
*/
#include <avr/io.h>
#include <avr/interrupt.h>
#include <stdbool.h>
#include "speaker.h"
static bool value = false;
static void speakerSet () {
if (value) {
PORTD = PORTD | (1 << PD6);
} else {
PORTD = PORTD & ~(1 << PD6);
}
}
ISR(TIMER2_OVF_vect) {
value = !value;
speakerSet ();
}
void speakerInit () {
/* set PD6 to output */
DDRD |= (1 << PD6);
/* value is false */
speakerSet ();
}
void speakerStart () {
/* reset timer value */
TCNT2 = 0;
/* set normal mode timer0 */
TCCR2A = 0;
/* enable overflow interrupt */
TIMSK2 = (1 << TOIE2);
/* io clock with 1024 prescaler */
TCCR2B = ((TCCR2B & ~(1 << CS21)) | (1 << CS22) | (1 << CS20));
}
void speakerStop () {
/* zero clock source */
TCCR2B = 0;
value = false;
speakerSet ();
}
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