funkstuff/input.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 "input.h"
#include "event.h"

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

static uint8_t pcint_old;
static uint8_t quad_state;
static uint8_t quad_state_old;
static uint8_t debounce_timer[2];

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

ISR(PCINT1_vect)
{
    uint8_t pcint_new       = PINC & PCMSK1;
    uint8_t pcint           = pcint_new ^ pcint_old;
    uint8_t quad_state_new  = quad_state;

    /* quadruple decoder A changed */
    if (pcint & (1<<PINC0))
    {
        /* positive edge */
        if (pcint_new & (1<<PINC0))
        {
            if ((quad_state == 0) || (quad_state == 2))
            {
                quad_state_new++;
            }
        }
        /* negative edge */
        else
        {
            if ((quad_state == 1) || (quad_state == 3))
            {
                quad_state_new--;
            }
        }
    }
    /* quadruple decoder B changed */
    else if (pcint & (1<<PINC1))
    {
        /* positive edge */
        if (pcint_new & (1<<PINC1))
        {
            if ((quad_state == 0) || (quad_state == 1))
            {
                quad_state_new += 2;
            }
        }
        /* negative edge */
        else
        {
            if ((quad_state == 2) || (quad_state == 3))
            {
                quad_state_new -= 2;
            }
        }
    }
    /* quadruple decoder switch changed */
    else if (pcint & (1<<PINC2))
    {
        if (debounce_timer[0] == 0)
        {
            debounce_timer[0] = 60; /* ~60ms */

            event_queue(EVENT_TYPE_INPUT,
                        EVENT_NUM_INPUT_BUTTON,
                        !!(pcint_new & (1<<PINC2))
                        );
        }
    }
    /* door switch changed */
    else if (pcint & (1<<PINC3))
    {
        if (debounce_timer[1] == 0)
        {
            debounce_timer[1] = 60; /* ~60ms */

            event_queue(EVENT_TYPE_INPUT,
                        EVENT_NUM_INPUT_DOOR,
                        !!(pcint_new & (1<<PINC3))
                        );
        }
    }

    /* one revolution completed? */
    if ((quad_state_new == 3) && (quad_state_old == 0))
    {
        /* counter clock wise */
        if (quad_state == 1)
        {
            event_queue(EVENT_TYPE_INPUT,
                        EVENT_NUM_INPUT_QUAD,
                        EVENT_VALUE_INPUT_QUAD_DEC
                       );
        }
        /* clock wise */
        else if (quad_state == 2)
        {
            event_queue(EVENT_TYPE_INPUT,
                        EVENT_NUM_INPUT_QUAD,
                        EVENT_VALUE_INPUT_QUAD_INC
                       );
        }
    }

    /* remember every two states */
    if ((quad_state_new == 0) || (quad_state_new == 3))
    {
        quad_state_old = quad_state_new;
    }

    quad_state = quad_state_new;

    pcint_old = pcint_new;
} /* PCINT1_vect */


void input_tick(void)
{
    if (debounce_timer[0] > 0)
    {
        debounce_timer[0]--;
    }

    if (debounce_timer[1] > 0)
    {
        debounce_timer[1]--;
    }
} /* input_tick */


void input_init(void)
{
    /* pullup on all inputs */
    DDRC &= ~((1<<PORTC3) | (1<<PORTC2) | (1<<PORTC1) | (1<<PORTC0));
    PORTC |= (1<<PORTC3) | (1<<PORTC2) | (1<<PORTC1) | (1<<PORTC0);

    /* Pinchange Interrupts enabled */
    PCMSK1 = (1<<PCINT11) | (1<<PCINT10) | (1<<PCINT9) | (1<<PCINT8);
    PCICR = (1<<PCIE1);

    /* initial pin interrupt state */
    pcint_old = PINC & PCMSK1;

    /* initial quadruple decoder state */
    quad_state = PINC & ((1<<PINC0) | (1<<PINC1));

    /* send button state */
    event_queue(EVENT_TYPE_INPUT,
                EVENT_NUM_INPUT_BUTTON,
                !!(pcint_old & (1<<PINC2))
                );

    /* send door state */
    event_queue(EVENT_TYPE_INPUT,
                EVENT_NUM_INPUT_DOOR,
                !!(pcint_old & (1<<PINC3))
                );
} /* input_init */