Subversion Repositories idreammicro-avr

/**************************************************************************//**
 * \brief ADC library.
 * \author Copyright (C) 2012  Julien Le Sech - www.idreammicro.com
 * \version 1.0
 * \date 20121029
 *
 * This file is part of the iDreamMicro library.
 *
 * This library is free software: you can redistribute it and/or modify it under
 * the terms of the GNU Lesser General Public License as published by the Free
 * Software Foundation, either version 3 of the License, or (at your option) any
 * later version.
 *
 * This library 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 Lesser General Public License for more
 * details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program. If not, see http://www.gnu.org/licenses/
 ******************************************************************************/

/**************************************************************************//**
 * \file adc.c
 ******************************************************************************/

/******************************************************************************
 * Header file inclusions.
 ******************************************************************************/

#include "../adc.h"

#include <useful/bits.h>

#include <avr/io.h>

#include <stdint.h>

/******************************************************************************
 * Public function definitions.
 ******************************************************************************/

/**************************************************************************//**
 * \fn void adc__single_channel_initialize(adc__channel_t channel)
 *
 * \brief Initialize ADC.
 *
 * \param channel   ADC channel.
 ******************************************************************************/
void
adc__single_channel_initialize
(
    adc__channel_t channel
){
    // Enable ADC.
    BIT__SET(ADCSRA, ADEN);

    // Clock prescaled by 16.
    // If Clock speed is 16 MHz, then ADC clock = 16 MHz / 16 = 1 MHz.
    ADCSRA |= 0b00000100;

    // Disable Digital Input on ADC Channel 0 to reduce power consumption
    DIDR0 = 0b00111111;

    // Disable Left-Adjust.
    ADMUX = 0b01000000;

    // Select ADC channel as input.
    ADMUX |= channel;
}

/**************************************************************************//**
 * \fn uint16_t adc__single_channel_read(void)
 *
 * \brief Read ADC.
 *
 * \return Read value.
 ******************************************************************************/
uint16_t
adc__single_channel_read
(
    void
){
    // Start ADC Conversion.
    BIT__SET(ADCSRA, ADSC);

    // Wait till conversion is complete.
    //while ((ADCSRA & (1 << ADIF)) != 0x10);
    while (!BIT__TST(ADCSRA, ADIF));

    // Read the ADC Result.
    uint16_t value = ADC;

    // Clear ADC Conversion Interrupt Flag.
    BIT__RST(ADCSRA, ADIF);

    return value;
}