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/*
* spreadspace avr utils
*
*
* Copyright (C) 2021 Christian Pointner <equinox@spreadspace.org>
*
* This file is part of spreadspace avr utils.
*
* spreadspace avr utils 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, either version 3 of the License, or
* any later version.
*
* spreadspace avr utils 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 spreadspace avr utils. If not, see <http://www.gnu.org/licenses/>.
*/
#include <avr/io.h>
#include <avr/interrupt.h>
#include "rotary.h"
#define DEBOUNCE_MAX 100
uint8_t last_stable = 0;
static inline uint8_t get_current(void)
{
return (PINB & ((1<<PB4) | (1<<PB5))) >> PB4;
}
void rotary_init(void)
{
DDRB &= ~((1<<PB4) | (1<<PB5));
PORTB |= (1<<PB4) | (1<<PB5);
last_stable = get_current();
}
rotary_dir_t rotary_task(void)
{
static uint8_t last = 0;
static uint8_t cnt = 0;
uint8_t current = get_current();
if(last == current)
cnt += (cnt < DEBOUNCE_MAX) ? 1 : 0;
else
cnt -= (cnt > 0) ? 1 : 0;
last = current;
if(cnt < DEBOUNCE_MAX)
return rotary_dir_none;
cnt = 0;
rotary_dir_t dir = rotary_dir_none;
if(last_stable != current) {
switch(last_stable) {
case 0:
if(current == 1) dir = rotary_dir_up;
if(current == 2) dir = rotary_dir_down;
break;
case 1:
if(current == 3) dir = rotary_dir_up;
if(current == 0) dir = rotary_dir_down;
break;
case 2:
if(current == 0) dir = rotary_dir_up;
if(current == 3) dir = rotary_dir_down;
break;
case 3:
if(current == 2) dir = rotary_dir_up;
if(current == 1) dir = rotary_dir_down;
break;
}
}
last_stable = current;
return dir;
}
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