adc_avr.h

/*
 * adc_avr.h - Interface to configure ADC speed and capture data for Atmel AVR chips.
 *
 * Copyright (C)2015 Laurentiu Badea
 *
 * This file may be redistributed under the terms of the MIT license.
 * A copy of this license has been included with this distribution in the file LICENSE.
 *
 * http://forum.arduino.cc/index.php/topic,6549.0.html
 */
#ifndef ADC_AVR_H_
#define ADC_AVR_H_
#include "adc.h"

#define ADC_BITS 10
#define ADC_CLOCK_TO_SAMPLING 13
#define ADC_AREF_MV 5000


// defines for setting and clearing register bits
#ifndef cbi
#define cbi(sfr, bit) (_SFR_BYTE(sfr) &= ~_BV(bit))
#endif
#ifndef sbi
#define sbi(sfr, bit) (_SFR_BYTE(sfr) |= _BV(bit))
#endif


class ADCInput : public ADCBase {
protected:
    uint8_t curMode;
    bool setPrescaler(uint8_t mode);
public:
    static const uint8_t prescalers[];
    uint8_t input;                           // analog input port
    uint8_t bits;                            // ADC resolution in bits
    bool init(uint8_t input=0, uint8_t mode=0);
    uint8_t getModeCount();          // returns the number of available rates
    bool setMode(uint8_t mode); // set sampling rate from the available values
    uint32_t getClock();       // Hz for information purposes only
    uint32_t getSampleRate();  // Hz for information purposes only
    void readMulti(uint16_t *buffer, unsigned size); // multi-sample read

    inline uint16_t read() __attribute__((always_inline)){
        return analogRead(input);
    }

    inline uint16_t readFast() __attribute__((always_inline)){
        // this runs just the conversion part of analogRead() without the setup
        sbi(ADCSRA, ADSC); // ADSC=AD Start Conversion
        loop_until_bit_is_clear(ADCSRA, ADSC); // Conversion finished
        return ADCL | (ADCH << 8);
    }
    uint16_t calibrateAREF();
};

#endif /* ADC_AVR_H_ */