funkstuff/pwm.c

/***************************************************************************
 *   Copyright (C) 11/2014 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 <avr/pgmspace.h>

#include "event.h"
#include "pwm.h"

#include "target.h"

/* *********************************************************************** */

const uint16_t pwmtable[128] PROGMEM =
{
    0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 4, 4, 5, 5,
    6, 6, 7, 8, 9, 9, 10, 11, 12, 14, 15, 16, 18, 20, 22, 24, 26,
    28, 31, 34, 37, 40, 44, 48, 53, 58, 63, 69, 75, 82, 90, 98,
    107, 116, 127, 139, 151, 165, 180, 196, 214, 234, 255, 278,
    303, 331, 361, 394, 430, 469, 511, 557, 608, 663, 723, 789,
    860, 938, 1023, 1116, 1217, 1327, 1447, 1578, 1721, 1877,
    2047, 2232, 2434, 2655, 2895, 3157, 3443, 3755, 4095, 4466,
    4870, 5311, 5792, 6316, 6888, 7511, 8191, 8932, 9741, 10623,
    11584, 12633, 13776, 15023, 16383, 17866, 19483, 21246, 23169,
    25267, 27553, 30047, 32767, 35733, 38967, 42494, 46340, 50534,
    55108, 60096, 65535
};

#define PWMTABLE_SIZE           (sizeof(pwmtable) / sizeof(uint16_t))

static uint8_t pwm_index[2];
static uint8_t pwm_setpoint[2];
static uint8_t pwm_setpoint_save[2];

/* *********************************************************************** */

void pwm_event_handler(struct event_entry *event)
{
    uint8_t channel = event->num;

    if (event->type == EVENT_TYPE_PWM_COMMAND)
    {
        switch (event->value)
        {
            case EVENT_VALUE_PWM_KEEP:
                pwm_setpoint[channel] = pwm_index[channel];
                break;

            /* increment PWM */
            case EVENT_VALUE_PWM_INC:
                if (pwm_setpoint[channel] < (PWMTABLE_SIZE -1))
                {
                    pwm_setpoint[channel]++;
                }
                break;

            /* decrement PWM */
            case EVENT_VALUE_PWM_DEC:
                if (pwm_setpoint[channel] > 0)
                {
                    pwm_setpoint[channel]--;
                }
                break;

            /* fade to min */
            case EVENT_VALUE_PWM_FADE_MIN:
                pwm_setpoint[channel] = 0;
                break;

            /* fade to max */
            case EVENT_VALUE_PWM_FADE_MAX:
                pwm_setpoint[channel] = (PWMTABLE_SIZE -1);
                break;

            // FIXME: move to some other module?
            case PWM_MODE_TOGGLE:
                if (pwm_setpoint[channel] > 5)
                {
                    pwm_setpoint_save[channel] = pwm_setpoint[channel];
                    pwm_setpoint[channel] = 0;
                }
                else
                {
                    pwm_setpoint[channel] = pwm_setpoint_save[channel];
                }
                break;

            default:
                break;
        }

        PWM_TIM_ENABLE();
    }
    else if (event->type == EVENT_TYPE_PWM_VALUE)
    {
        pwm_setpoint[event->num] = event->value;

        PWM_TIM_ENABLE();
    }
} /* pwm_event_handler */


static void pwm_update(uint8_t channel)
{
    if ((pwm_setpoint[channel] > pwm_index[channel]) &&
        (pwm_index[channel] < (PWMTABLE_SIZE -1))
        )
    {
        pwm_index[channel]++;
    }
    else if ((pwm_setpoint[channel] < pwm_index[channel]) &&
                (pwm_index[channel] > 0)
            )
    {
        pwm_index[channel]--;
    }

    /* if PWM is zero, disable output */
    if (pwm_index[channel] == 0)
    {
        if (channel == 0)
        {
            PWM_CH0_OFF();
        }
        else
        {
            PWM_CH1_OFF();
        }
    }
    /* if PWM is max, enable output */
    else if (pwm_index[channel] == (PWMTABLE_SIZE -1))
    {
        if (channel == 0)
        {
            PWM_CH0_ON();
        }
        else
        {
            PWM_CH1_ON();
        }
    }
    /* else load new PWM into timer */
    else
    {
        if (channel == 0)
        {
            PWM_CH0_PWM(pgm_read_word(&pwmtable[pwm_index[0]]));
        }
        else
        {
            PWM_CH1_PWM(pgm_read_word(&pwmtable[pwm_index[1]]));
        }
    }
} /* pwm_set */


ISR(PWM_TIM_VECT)
{
    static uint8_t delay;

    delay++;
    if (delay == 4)
    {
        delay = 0;

        /* update PWM values */
        pwm_update(0);
        pwm_update(1);

        /* disable timer if both channels are ON or OFF */
        if (PWM_TIM_CHECK())
        {
            PWM_TIM_ENABLE();
        }
        else
        {
            PWM_TIM_DISABLE();
        }
    }
} /* TIM1_OVF_vect */


void pwm_init(void)
{
    PWM_TIM_INIT();
} /* pwm_init */