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

#include "lights.h"

void init_pwm()
{
	/* Async clock */
	PLLCSR = _BV(PLLE);

	/* Synchronize to the phase lock */
	_delay_ms(1);
	while ((PLLCSR & _BV(PLOCK)) == 0)
		;
	PLLCSR |= _BV(PCKE);

	// PWM channel D is inverted, ...
	TCCR1C = _BV(COM1D1) | _BV(COM1D0) | _BV(PWM1D);
	// PWM channels A and B are not
	TCCR1A = _BV(COM1A1) | _BV(COM1B1) | _BV(PWM1A) | _BV(PWM1B);
	TCCR1D = 0;
	TCCR1B = _BV(CS10); 			// no clock prescaling

	TC1H = PWM_MAX >> 8;
	OCR1C = PWM_MAX & 0xFF;				// TOP value

	TC1H = PWM_MAX >> 8;		// PWM3 is inverted
	OCR1D = PWM_MAX & 0xFF;

	TC1H = 0x00;
	OCR1B = OCR1A = 0;		// initial stride is 0

	DDRB  &= ~(_BV( PB1 ) | _BV( PB3 ) | _BV( PB5 )); // tristate it
	PORTB &= ~(_BV( PB1 ) | _BV( PB3 ) | _BV( PB5 )); // set to zero
}

void susp_pwm()
{
	DDRB &= ~(_BV( PB1 ) | _BV( PB3 ) | _BV( PB5 ));
	TCCR1D = TCCR1C = TCCR1B = TCCR1A = 0;
	TIMSK = 0;
	TIFR = 0;
}

void pwm_off(unsigned char n)
{
	switch (n) {
	case 0: DDRB &= ~_BV(PB1); break;
	case 1: DDRB &= ~_BV(PB3); break;
	case 2: DDRB &= ~_BV(PB5); break;
	}
}

void pwm_set(unsigned char n, uint16_t stride)
{
	unsigned char hi, lo;

	if (stride > PWM_MAX)
		stride = PWM_MAX;

	if (n == 2)
		stride = PWM_MAX - stride;

	hi = stride >> 8;
	lo = stride & 0xFF;

	switch (n) {
	case 0:
		TC1H = hi;
		OCR1A = lo;
		DDRB |= _BV(PB1);
		break;
	case 1:
		TC1H = hi;
		OCR1B = lo;
		DDRB |= _BV(PB3);
		break;
	case 2:
		TC1H = hi;
		OCR1D = lo;
		DDRB |= _BV(PB5);
		break;
	}
}

#if 0
static void inline pwm_handler()
{
	OCR1A = pwmval[0];
	OCR1B = pwmval[1];
	OCR1D = pwmval[2];
	TIMSK &= ~_BV(TOIE1);
}

ISR(TIMER1_OVF_vect)
{
	pwm_handler();
}
#endif