/***************************************************************************
 *   Copyright (C) 09/2007 by Olaf Rempel                                  *
 *   razzor@kopf-tisch.de                                                  *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; version 2 of the License,               *
 *                                                                         *
 *   This program is distributed in the hope that it will be useful,       *
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
 *   GNU General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program; if not, write to the                         *
 *   Free Software Foundation, Inc.,                                       *
 *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
 ***************************************************************************/
#include <avr/io.h>
#include <avr/interrupt.h>

#include "main.h"
#include "blmc.h"

struct blmc_ blmc;

/* Analog Comparator Channel */
static uint8_t next_sense;

void trigger_adc(uint8_t channel)
{
	/* Disable Analog Comperator */
	ACSR &= ~(1<<ACIE);

	/* set channel (Internal reference, 2.56V) */
	ADMUX = (1<<REFS1) | (1<<REFS0) | channel;

	/* turn on ADC with interrupts, start conversion with 1/32 of F_CPU */
	ADCSRA = (1<<ADEN) | (1<<ADSC) | (1<<ADIE) | (1<<ADIF)| (1<<ADPS2) | (1<<ADPS0);
}

void next_phase(void)
{
	static uint8_t phase;
	static uint8_t phase_adc;

	/* Disable Analog Comperator */
	ACSR &= ~(1<<ACIE);

	TCNT1 = 0x00;
	TCNT2 = 0x00;

	switch (phase) {
	case 0:	PORTD = (PORTD & ~PHASE_L_MASK) | PHASE_B_L;
		TCCR1A = (TCCR1A & ~(1<<COM1B1)) | (1<<COM1A1);
		TCCR2 &= ~(1<<COM21);
		ACSR = (1<<ACIS1);
		next_sense = SENSE_C;
		break;

	case 1:	PORTD = (PORTD & ~PHASE_L_MASK) | PHASE_B_L;
		TCCR1A &= ~((1<<COM1A1) | (1<<COM1B1));
		TCCR2 |= (1<<COM21);
		ACSR = (1<<ACIS1) | (1<<ACIS0);
		next_sense = SENSE_A;
		break;

	case 2:	PORTD = (PORTD & ~PHASE_L_MASK) | PHASE_A_L;
		TCCR1A &= ~((1<<COM1A1) | (1<<COM1B1));
		TCCR2 |= (1<<COM21);
		ACSR = (1<<ACIS1);
		next_sense = SENSE_B;
		break;

	case 3:	PORTD = (PORTD & ~PHASE_L_MASK) | PHASE_A_L;
		TCCR1A = (TCCR1A & ~(1<<COM1A1)) | (1<<COM1B1);
		TCCR2 &= ~(1<<COM21);
		ACSR = (1<<ACIS1) | (1<<ACIS0);
		next_sense = SENSE_C;
		break;

	case 4:	PORTD = (PORTD & ~PHASE_L_MASK) | PHASE_C_L;
		TCCR1A = (TCCR1A & ~(1<<COM1A1)) | (1<<COM1B1);
		TCCR2 &= ~(1<<COM21);
		ACSR = (1<<ACIS1);
		next_sense = SENSE_A;
		break;

	case 5:	PORTD = (PORTD & ~PHASE_L_MASK) | PHASE_C_L;
		TCCR1A = (TCCR1A & ~(1<<COM1B1)) | (1<<COM1A1);
		TCCR2 &= ~(1<<COM21);
		ACSR = (1<<ACIS1) | (1<<ACIS0);
		next_sense = SENSE_B;
		break;
	}

	if (phase == (phase_adc & 0x0F)) {
		if (phase_adc & 0x10)
			trigger_adc(SENSE_VOLTAGE);
		else
			trigger_adc(SENSE_CURRENT);

		phase_adc--;
		if (phase_adc == 0xff)
			phase_adc = 0x15;

		else if (phase_adc == 0x0f)
			phase_adc = 0x05;

	} else {
		/* restore channel */
		ADMUX = next_sense;

		/* enable Analog Comparator with Interrupts */
		if (blmc.flags & FLAG_COM_NORMAL)
			ACSR |= (1<<ACIE) | (1<<ACI);
	}

	phase++;
	if (phase == 6)
		phase = 0;

	blmc.rpm_tmp++;
}

/*
 * starts motor, must not run from interrupt
 */
void spinup(void)
{
	uint16_t time = 1000;
	while (time > 50) {
		next_phase();

		uint16_t i;
		for (i = 0; i < time; i++)
			_delay_us(25);

		time -= (time / 24 +1);
	}

	/* manual spinup complete, analog comperator takes control */
	blmc.flags = FLAG_PWM_SPINUP | FLAG_COM_NORMAL;
	next_phase();

	for (time = 0; time < 10; time++)
		_delay_ms(20);

	/* switch to desired pwm value */
	blmc.flags = FLAG_PWM_NORMAL | FLAG_COM_NORMAL;
}

/*
 * sets new pwm value
 * called from i2c-slave (set new value) and from timer (recalc current limit)
 */
void setpwm(uint8_t pwm)
{
	/* run motor *only* if there are no hard errors */
	if (pwm >= 8 && !(blmc.flags & FLAG_HARDERR_MASK)) {
		/* do a spinup */
		if (blmc.pwm == 0)
			blmc.flags = FLAG_PWM_SPINUP | FLAG_COM_SPINUP;

	} else {
		blmc.flags &= ~FLAG_RUN_MASK;
		pwm = 0;
	}

	/* do spinup with small pwm */
	if (blmc.flags & FLAG_PWM_SPINUP)
		pwm = 0x0f;

	/* save pwm value */
	blmc.pwm = pwm;

	/* raise current limit, TODO: magic value */
	if (blmc.current > 120)
		blmc.pwm_limit++;

	/* lower current limit */
	else if (blmc.pwm_limit > 0)
		blmc.pwm_limit--;

	/* set soft current flag */
	if (blmc.pwm_limit)
		blmc.flags |= FLAG_CURRENTLIMIT;
	else
		blmc.flags &= ~FLAG_CURRENTLIMIT;

	/* prevent overflow */
	if (blmc.pwm_limit > pwm)
		blmc.pwm_limit = pwm;

	/* set new value */
	pwm -= blmc.pwm_limit;
	OCR1A = pwm;
	OCR1B = pwm;
	OCR2 = pwm;
}

ISR(ANA_COMP_vect)
{
	next_phase();
}

ISR(ADC_vect)
{
	static uint16_t current_tmp, voltage_tmp;
	static uint8_t current_cnt, voltage_cnt;

	uint8_t channel = ADMUX & 0x0F;
	uint16_t value = ADCW;

	/* restore channel */
	ADMUX = next_sense;

	/* turn off ADC, disable interrupt */
	ADCSRA = 0x00;

	/* enable Analog Comparator with Interrupts */
	if (blmc.flags & FLAG_COM_NORMAL)
		ACSR |= (1<<ACIE) | (1<<ACI);

	if (channel == SENSE_CURRENT) {
		current_tmp += value;
		current_cnt++;
		if (current_cnt == 6) {
			blmc.current = current_tmp;
			current_tmp = 0;
			current_cnt = 0;
		}
		// TODO: overcurrent shutdown

	} else {
		voltage_tmp += value;
		voltage_cnt++;
		if (voltage_cnt == 6) {
			blmc.voltage = voltage_tmp;
			voltage_tmp = 0;
			voltage_cnt = 0;
		}
		// TODO: undervoltage shutdown
	}
}