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/* LED pwm, uses timer0
*/
#include "common.h"
#include <avr/io.h>
#include <avr/interrupt.h>
#include <stdbool.h>
#include <assert.h>
#include <stdlib.h>
#include "speaker.h"
#include "pwm.h"
/* max count for blinks */
static uint8_t blink[6];
static uint8_t comphit = 0;
static uint8_t state = 0;
/* PORTB and PORTB values */
static uint8_t val[2];
static uint8_t init[2];
static void ledOff () {
PORTB = PORTB & ~((1 << PB6) | (1 << PB7));
PORTD = PORTD & ~((1 << PD2) | (1 << PD3) | (1 << PD4) | (1 << PD5));
}
static uint8_t ledToArray (const uint8_t i) {
assert (i < PWM_LED_COUNT);
if (i >= 2) {
return 1;
} else {
return 0;
}
}
static uint8_t ledToShift (const uint8_t i) {
assert (i < PWM_LED_COUNT);
static const uint8_t shifts[] = {PB6, PB7, PD2, PD3, PD4, PD5};
return shifts[i];
}
/* All LEDs are off for state % 2 == 0 (off state) or state >= 7 (end of blink
* sequence), setting blink[i] = state*2 causes LED i to blink state times
*/
ISR(TIMER0_COMPA_vect) {
++comphit;
/* divide by 13 to get ~10 Hz timer */
if (comphit >= 13) {
comphit = 0;
++state;
if (state == 12) {
state = 0;
}
val[0] = init[0];
val[1] = init[1];
if (state >= 10 || state % 2 == 0) {
/* end of blink/off state */
} else {
for (uint8_t i = 0; i < PWM_LED_COUNT; i++) {
if (state < blink[i]) {
val[ledToArray (i)] |= (1 << ledToShift(i));
}
}
}
}
if (comphit % 2 == 0) {
ledOff ();
} else {
PORTB |= val[0];
PORTD |= val[1];
}
}
void pwmInit () {
/* set led1,led2 to output */
DDRB |= (1 << PB6) | (1 << PB7);
/* set led3,led4,led5,led6 to output */
DDRD |= (1 << PD2) | (1 << PD3) | (1 << PD4) | (1 << PD5);
}
void pwmStart () {
comphit = 0;
state = 0;
/* reset timer value */
TCNT0 = 0;
/* set ctc timer0 (part 1) */
TCCR0A = (1 << WGM01);
/* enable compare match interrupt */
TIMSK0 = (1 << OCIE0A);
/* compare value */
OCR0A = 255;
/* io clock with prescaler 256; ctc (part 2) */
TCCR0B = (1 << CS02) | (0 << CS01) | (0 << CS00);
}
void pwmStop () {
/* zero clock source */
TCCR0B = 0;
ledOff ();
}
void pwmSetBlink (const uint8_t i, const uint8_t value) {
assert (i < PWM_LED_COUNT);
if (value == PWM_BLINK_ON) {
/* permanently switch on LED */
init[ledToArray (i)] |= (1 << ledToShift (i));
} else {
init[ledToArray (i)] &= ~(1 << ledToShift (i));
blink[i] = value*2;
}
}
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