button-sensor.c

/*Button sensor routine 
* Author: Georg von Zengen 
*/

#include "lib/sensors.h"
#include "dev/button-sensor.h"
#include <avr/io.h>
#include <avr/interrupt.h>
const struct sensors_sensor button_sensor;
static int status(int type);
static struct timer debouncetimer;
ISR(INT2_vect){

        if(timer_expired(&debouncetimer)) {
                timer_set(&debouncetimer, CLOCK_SECOND / 40);
                sensors_changed(&button_sensor);
        }

}

static int
value(int type)
{
        return 1-((PINB & (1<<PB2))>>PB2) || !timer_expired(&debouncetimer);
}

static int
configure(int type, int c)
{
        switch (type) {
        case SENSORS_ACTIVE:
                if (c) {
                        if(!status(SENSORS_ACTIVE)) {
                                timer_set(&debouncetimer, CLOCK_SECOND / 40);
                                DDRB &= ~(1<<PB2);
                                PORTB &= ~(1<<PB2);
                                sei();
                                EICRA |= (1<<ISC20);
                                EIMSK |= (1<<INT2);
                        }
                } else {
                        DDRB |= (1<<PB2);
                        PORTB |= (1<<PB2);
                        EIMSK &= ~(1<<INT2);
                }
                return 1;
        }
        return 0;
}

static int
status(int type)
{
        switch (type) {
        case SENSORS_ACTIVE:
                return 0;
        case SENSORS_READY:
                return ~(DDRB & (1<<PB2));
        }

        return 0;
}

SENSORS_SENSOR(button_sensor, BUTTON_SENSOR,
               value, configure, status);