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/* adc.c */
/* n.avr.adc - AVR ADC Module. {{{
 *
 * Copyright (C) 2005 Thomas Burg
 *
 * 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; either version 2 of the License, or
 * (at your option) any later version.
 * 
 * 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.
 *
 * Contact :
 *      Email: <burg@efrei.fr>
 * }}} */
#include "adc.h"
#include "n/avr/utils/utils.h"

#include <avr/io.h>
#include <avr/signal.h>

/* Tested AVR check. */
#if defined (__AVR_ATmega8__)
#elif defined (__AVR_ATmega8535__)
#elif defined (__AVR_ATmega128__)
#else
# warning "adc: not tested on this chip."
#endif

/* Different name on ATmega8535. */
#if defined (__AVR_ATmega8535__)
#define ADCSR ADCSRA
#endif

/* +AutoDec */
/* -AutoDec */

/** Initialise adc. */
void
adc_init (void)
{
    /* REFS = 01: AVCC with external capacitor at AREF pin.
     *        11: Internal 2.56V Voltage Reference with external capacitor
     *        at AREF pin. */
    ADMUX = regv (REFS1, REFS0, ADLAR, MUX4, MUX3, MUX2, MUX1, MUX0,
		      1,     1,     0,    0,    0,    0,    0,    0);
    /* Adc enabled. */
    ADCSR = regv (ADEN, ADSC, ADATE, ADIF, ADIE, ADPS2, ADPS1, ADPS0,
		     1,    0,     0,    0,    0,     0,     0,     0);
}

/** Choose and start mesure on adc line. */
void
adc_start (uint8_t d)
{
    /* Choose adc. */
    ADMUX |= d & 0x07;
    /* ADEN active l'adc
     * ADSC demarre la mesure */
    ADCSR |= _BV (ADSC);
}

/** Return a value different of zero if finished. */
uint8_t
adc_checkf (void)
{
    return !(ADCSR & _BV (ADSC));
}

/** Read mesure. */
uint16_t
adc_read (void)
{
    return ADCW;
}