//-------------------------------------------------------------------
// Filename: hal_adc.c
// Description: These functions/macros simplifies usage of the ADC.
//-------------------------------------------------------------------
#include "hal_defs.h"
#include "hal_adc.h"

//-------------------------------------------------------------------
// @fn  adcSampleSingle
// @brief
//     This function makes the adc sample the given channel at the given
//     resolution with the given reference.
// @param uint8 reference
//         The reference to compare the channel to be sampled.
//       uint8 resolution
//         The resolution to use during the sample (8, 10, 12 or 14 bit)
//       uint8 input
//         The channel to be sampled.
// @return int16
//         The conversion result
//-------------------------------------------------------------------
unsigned int adcSampleSingle(uint8 reference, uint8 resolution, uint8 channel)
{
    unsigned int value;

    ADC_ENABLE_CHANNEL(channel);

    ADCIF = 0;
    ADC_SINGLE_CONVERSION(reference | resolution | channel);
    while (!ADCIF)
        ;

    value = ((unsigned int) ADCH) << 8;
    value |= (unsigned int) ADCL;
    
    if(value & 0x8000)
    {
         value = 0;
    }
    
    value = value & 0x7FF8;

    ADC_DISABLE_CHANNEL(channel);

    //  The variable 'value' contains 16 bits where
    //     bit 15 is a sign bit
    //     bit [14 .. 0] contain the absolute sample value
    //     Only the r upper bits are significant, where r is the resolution
    //     Resolution:
    //        12   -> [14 .. 3] (bitmask 0x7FF8)
    //        10   -> [14 .. 5] (bitmask 0x7FE0)
    //         9   -> [14 .. 6] (bitmask 0x7FC0)
    //         7   -> [14 .. 8] (bitmask 0x7F00)

    return value;
}