esp-fc

#include "BaroBMP085.hpp"
#include "Hal/Time.hpp"
#include <cmath>

#define BMP085_DEFAULT_ADDRESS 0x77
#define BMP085_WHOAMI_ID 0x55

#define BMP085_CALIB_REG 0xAA
#define BMP085_WHOAMI_REG 0xD0
#define BMP085_RESET_REG 0xE0
#define BMP085_CONTROL_REG 0xF4
#define BMP085_MEASUREMENT_REG 0xF6

#define BMP085_MEASURE_T 0x2E  // temperature measurent
#define BMP085_MEASURE_P0 0x34 // pressure measurement no oversampling
#define BMP085_MEASURE_P1 0x74 // pressure measurement oversampling x2
#define BMP085_MEASURE_P2 0xB4 // pressure measurement oversampling x4
#define BMP085_MEASURE_P3 0xF4 // pressure measurement oversampling x8

namespace Espfc::Device::Baro {

int BaroBMP085::begin(Hal::BusDevice* bus)
{
  return begin(bus, BMP085_DEFAULT_ADDRESS);
}

int BaroBMP085::begin(Hal::BusDevice* bus, uint8_t addr)
{
  setBus(bus, addr);

  if (!testConnection()) return 0;

  _bus->writeByte(_addr, BMP085_RESET_REG, 0xB6); // device reset
  delay(10);

  _bus->read(_addr, BMP085_CALIB_REG, sizeof(CalibrationData), (uint8_t*)&_cal);

  return 1;
}

BaroDeviceType BaroBMP085::getType() const
{
  return BARO_BMP085;
}

float BaroBMP085::readTemperature()
{
  uint8_t buffer[2];
  _bus->read(_addr, BMP085_MEASUREMENT_REG, 2, buffer);

  // calbrate temp
  int32_t ut = ((uint16_t)buffer[0] << 8) + buffer[1];
  if (ut == 0) return NAN;

  int32_t x1 = ((ut - (int32_t)_cal.ac6) * (int32_t)_cal.ac5) >> 15;
  int32_t x2 = ((int32_t)_cal.mc << 11) / (x1 + _cal.md);
  _t_fine = x1 + x2;
  //_t_fine = (_t_fine + x1 + x2 + 1) >> 1; // avg of last two samples
  return (float)((_t_fine + 8) >> 4) * 0.1f;
}

float BaroBMP085::readPressure()
{
  uint8_t buffer[3];
  _bus->read(_addr, BMP085_MEASUREMENT_REG, 3, buffer);

  uint32_t up = ((uint32_t)buffer[0] << 16) | ((uint32_t)buffer[1] << 8) | buffer[2];

  uint8_t oss = (_mode & 0xC0) >> 6;
  if (_mode & 0x34) up = up >> (8 - oss);
  if (up == 0) return NAN;

  int32_t b6 = _t_fine - 4000;
  int32_t x1 = ((int32_t)_cal.b2 * ((b6 * b6) >> 12)) >> 11;
  int32_t x2 = ((int32_t)_cal.ac2 * b6) >> 11;
  int32_t x3 = x1 + x2;
  int32_t b3 = ((((int32_t)_cal.ac1 * 4 + x3) << oss) + 2) >> 2;
  x1 = ((int32_t)_cal.ac3 * b6) >> 13;
  x2 = ((int32_t)_cal.b1 * ((b6 * b6) >> 12)) >> 16;
  x3 = ((x1 + x2) + 2) >> 2;
  uint32_t b4 = ((uint32_t)_cal.ac4 * (uint32_t)(x3 + 32768)) >> 15;
  uint32_t b7 = ((uint32_t)up - b3) * (uint32_t)(50000UL >> oss);

  int32_t p = 0;
  if (b7 < 0x80000000)
  {
    p = (b7 << 1) / b4;
  }
  else
  {
    p = (b7 / b4) << 1;
  }
  x1 = (p >> 8) * (p >> 8);
  x1 = (x1 * 3038) >> 16;
  x2 = (-7357 * p) >> 16;

  p = p + ((x1 + x2 + (int32_t)3791) >> 4);

  return p;
}

void BaroBMP085::setMode(BaroDeviceMode mode)
{
  _mode = mode == BARO_MODE_TEMP ? BMP085_MEASURE_T : BMP085_MEASURE_P3;
  _bus->writeByte(_addr, BMP085_CONTROL_REG, _mode);
}

int BaroBMP085::getDelay(BaroDeviceMode mode) const
{
  switch (mode)
  {
    case BARO_MODE_TEMP:
      return 4550; // temp
    default:
      // return 4550;  // press_0
      // return 7550;  // press_1
      // return 13550; // press_2
      return 25550; // press_3
  }
}

bool BaroBMP085::testConnection()
{
  uint8_t whoami = 0;
  if (_bus->readByte(_addr, BMP085_WHOAMI_REG, &whoami) != 1) return false;
  setChipId(whoami);
  if (whoami != BMP085_WHOAMI_ID) return false;
  return true;
}

} // namespace Espfc::Device::Baro