GY-63_MS5611/libraries/MS5611/MS5611.cpp

//
//    FILE: MS5611.cpp
//  AUTHOR: Rob Tillaart
//          Erni - testing/fixes
// VERSION: 0.3.0
// PURPOSE: MS5611 Temperature & Humidity library for Arduino
//     URL: https://github.com/RobTillaart/MS5611
//
//  HISTORY:
//  0.3.0   2021-01-27  fix #9 math error (thanks to Emiel Steerneman)
//                      add Wire1..WireN support (e.g. teensy)
//                      changed getTemperature() and getPressure()
//                      add reset()
//  0.2.2   2021-01-01  add Arduino-CI + unit tests + isConnected()
//  0.2.1   2020-06-28  fix #1 min macro compile error
//  0.2.0   2020-06-21  refactor; #pragma once; 
//  0.1.8               fix #109 incorrect constants (thanks to flauth)
//  0.1.7               revert double to float (issue 33)
//  0.1.6   2015-07-12  refactor
//  0.1.05  moved 6 float multiplies to init  [adds ~70 bytes !!!]
//          moved the MS5611_LIB_VERSION to PROGMEM
//  0.1.04  changed float to double (for platforms which support it)
//          changed divisions in multiplications
//          fixed uint32_t readADC()
//          reduced size of C array by 1 float
//          added second order temperature compensation
//  0.1.03  changed math to float [test version]
//  0.1.02  fixed bug return value read()
//          fixed bug #bits D2
//          added MS5611_READ_OK
//          added inline getters for temp & pres & lastresult.
//          adjusted delay's based on datasheet
//          merged convert functions
//          fixed offset in readProm()
//  0.1.01  small refactoring
//  0.1.00  added temperature and Pressure code
//  0.0.00  initial version by Rob Tillaart (15-okt-2014)


#include "MS5611.h"


// datasheet page 10
#define MS5611_CMD_READ_ADC       0x00
#define MS5611_CMD_READ_PROM      0xA0
#define MS5611_CMD_RESET          0x1E
#define MS5611_CMD_CONVERT_D1     0x40
#define MS5611_CMD_CONVERT_D2     0x50


/////////////////////////////////////////////////////
//
// PUBLIC
//
MS5611::MS5611(uint8_t deviceAddress)
{
  _address     = deviceAddress;
  _temperature = MS5611_NOT_READ;
  _pressure    = MS5611_NOT_READ;
  _result      = MS5611_NOT_READ;
  _lastRead    = 0;
}


#if defined (ESP8266) || defined(ESP32)
bool MS5611::begin(uint8_t dataPin, uint8_t clockPin, TwoWire * wire)
{
  if ((_address < 0x76) || (_address > 0x77)) return false;

  _wire = wire;
  if ((dataPin < 255) && (clockPin < 255))
  {
    _wire->begin(dataPin, clockPin);
  } else {
    _wire->begin();
  }
  if (! isConnected()) return false;

  reset();
  return true;
}
#endif


bool MS5611::begin(TwoWire * wire)
{
  if ((_address < 0x76) || (_address > 0x77)) return false;
  _wire = wire;
  _wire->begin();
  if (! isConnected()) return false;

  reset();
  return true;
}


bool MS5611::isConnected()
{
  _wire->beginTransmission(_address);
  return (_wire->endTransmission() == 0);
}


void MS5611::reset()
{
  command(MS5611_CMD_RESET);
  delay(3);
  // constants that were multiplied in read()
  // do this once and you save CPU cycles
  C[0] = 1;
  C[1] = 32768L;
  C[2] = 65536L;
  C[3] = 3.90625E-3;
  C[4] = 7.8125E-3;
  C[5] = 256;
  C[6] = 1.1920928955E-7;
  // read factory calibrations from EEPROM.
  for (uint8_t reg = 0; reg < 7; reg++)
  {
    // used indices match datasheet.
    // C[0] == manufacturer - read but not used;
    // C[7] == CRC - skipped.
    C[reg] *= readProm(reg);
  }
}


int MS5611::read(uint8_t bits)
{
  // VARIABLES NAMES BASED ON DATASHEET
  // ALL MAGIC NUMBERS ARE FROM DATASHEET

  convert(MS5611_CMD_CONVERT_D1, bits);
  if (_result) return _result;
  uint32_t D1 = readADC();
  if (_result) return _result;

  convert(MS5611_CMD_CONVERT_D2, bits);
  if (_result) return _result;
  uint32_t D2 = readADC();
  if (_result) return _result;
  
  //  TEST VALUES - comment lines above
  // uint32_t D1 = 9085466;
  // uint32_t D2 = 8569150;

  // TEMP & PRESS MATH - PAGE 7/20
  float dT = D2 - C[5];
  _temperature = 2000 + dT * C[6];

  float offset =  C[2] + dT * C[4];
  float sens = C[1] + dT * C[3];

  // SECOND ORDER COMPENSATION - PAGE 8/20
  // COMMENT OUT < 2000 CORRECTION IF NOT NEEDED
  // NOTE TEMPERATURE IS IN 0.01 C
  if (_temperature < 2000)
  {
    float T2 = dT * dT * 4.6566128731E-10;
    float t = (_temperature - 2000) * (_temperature - 2000);
    float offset2 = 2.5 * t;
    float sens2 = 1.25 * t;
    // COMMENT OUT < -1500 CORRECTION IF NOT NEEDED
    if (_temperature < -1500)
    {
      t = (_temperature + 1500) * (_temperature + 1500);
      offset2 += 7 * t;
      sens2 += 5.5 * t;
    }
    _temperature -= T2;
    offset -= offset2;
    sens -= sens2;
  }
  // END SECOND ORDER COMPENSATION

  _pressure = (D1 * sens * 4.76837158205E-7 - offset) * 3.051757813E-5;

  _lastRead = millis();
  return MS5611_READ_OK;
}


/////////////////////////////////////////////////////
//
// PRIVATE
//
void MS5611::convert(const uint8_t addr, uint8_t bits)
{
  uint8_t del[5] = {1, 2, 3, 5, 10};

  bits = constrain(bits, 8, 12);
  uint8_t offset = (bits - 8) * 2;
  command(addr + offset);
  delay(del[offset/2]);
}


uint16_t MS5611::readProm(uint8_t reg)
{
  // last EEPROM register is CRC - Page13 datasheet.
  uint8_t promCRCRegister = 7;
  if (reg > promCRCRegister) return 0;

  uint8_t offset = reg * 2;
  command(MS5611_CMD_READ_PROM + offset);
  if (_result == 0)
  {
    int nr = _wire->requestFrom(_address, (uint8_t)2);
    if (nr >= 2)
    {
      uint16_t val = _wire->read() * 256;
      val += _wire->read();
      return val;
    }
    return 0;
  }
  return 0;
}


uint32_t MS5611::readADC()
{
  command(MS5611_CMD_READ_ADC);
  if (_result == 0)
  {
    int nr = _wire->requestFrom(_address, (uint8_t)3);
    if (nr >= 3)
    {
      uint32_t val = _wire->read() * 65536UL;
      val += _wire->read() * 256UL;
      val += _wire->read();
      return val;
    }
    return 0UL;
  }
  return 0UL;
}


int MS5611::command(const uint8_t command)
{
  yield();
  _wire->beginTransmission(_address);
  _wire->write(command);
  _result = _wire->endTransmission();
  return _result;
}

// -- END OF FILE --