//
//    FILE: AnalogPin.cpp
//  AUTHOR: Rob Tillaart
// VERSION: 0.2.6
//    DATE: 2013-09-09
// PURPOSE: wrapper for analogRead with smoothing and noise filtering
//
//  HISTORY:
//  0.1.00  2013-09-09  initial version
//  0.1.01  2013-11-09  added some comments
//  0.1.02  2014-10-05  changed signatures data types
//  0.1.03  2014-12-07  some refactor
//  0.1.04  2015-03-06  refactor smaller footprint
//  0.2.00  2015-05-14  added pre-scale support
//  0.2.01  2015-12-19  breaking interface; big refactor;
//  0.2.2   2020-03-25  refactor AVR specific code; bugfix
//  0.2.3   2020-05-27  update library.json
//  0.2.4   2020-12-10  add Arduino-ci
//  0.2.5   2021-10-17  update Arduino-CI
//  0.2.6   2021-12-12  update library.json, license, minor edits.


#include "AnalogPin.h"


AnalogPin::AnalogPin(const uint8_t pin)
{
  _pin      = pin;
  _prescale = 7;
  _alpha    = 0;
  _noise    = 0;
  _rawRead();
  _prevValue = _value;
}


void AnalogPin::setPrescaler(const uint8_t prescale)
{
  _prescale = prescale; 
  if (_prescale < 2)      _prescale = 2; 
  else if (_prescale > 7) _prescale = 7; 
};


void AnalogPin::setSmoothWeight(const uint8_t alpha)
{
  _alpha = alpha;
  if (_alpha > 31) _alpha = 31;
};


int AnalogPin::read(const bool twice)
{
  if (twice) _rawRead();
  _rawRead();
  if ( (_noise == 0) || (((_value - _prevValue) & 0x7FFF) > _noise) )
  {
    _prevValue = _value;
  }
  return _prevValue;
}


int AnalogPin::readSmoothed()
{
  _rawRead();
  if (_alpha > 0)
  {
    _value = _value + (_alpha * (_prevValue - _value)) / 32;
  }
  _prevValue = _value;
  return _value;
}


void AnalogPin::_rawRead()
{
#if defined(ARDUINO_ARCH_AVR)
  // remember old register value
  uint8_t ADCSRA_TMP = ADCSRA;
  ADCSRA = (ADCSRA | 0x07) & (0xF8 | _prescale);
#elif defined(ARDUINO_ARCH_SAM)

#else

#endif

  _value = analogRead(_pin);

#if defined(ARDUINO_ARCH_AVR)
  // restore register
  ADCSRA = ADCSRA_TMP;
#elif defined(ARDUINO_ARCH_SAM)

#else

#endif
}


// -- END OF FILE --