BME680 etwas ATMega-freundlicher auslesen

/*!

 * @brief This internal API is used to calculate the temperature value.

 */

static int16_t calc_temperature(uint32_t temp_adc, struct bme680_dev *dev)

{

  int64_t var1;

  int64_t var2;

  int64_t var3;

  int16_t calc_temp;

  var1 = ((int32_t) temp_adc >> 3) - ((int32_t) dev->calib.par_t1 << 1);

  var2 = (var1 * (int32_t) dev->calib.par_t2) >> 11;

  var3 = ((var1 >> 1) * (var1 >> 1)) >> 12;

  var3 = ((var3) * ((int32_t) dev->calib.par_t3 << 4)) >> 14;

  dev->calib.t_fine = (int32_t) (var2 + var3);

  calc_temp = (int16_t) (((dev->calib.t_fine * 5) + 128) >> 8);

  return calc_temp;

}

/*!

 * @brief This internal API is used to calculate the pressure value.

 */

static uint32_t calc_pressure(uint32_t pres_adc, const struct bme680_dev *dev)

{

  int32_t var1;

  int32_t var2;

  int32_t var3;

  int32_t pressure_comp;

  var1 = (((int32_t)dev->calib.t_fine) >> 1) - 64000;

  var2 = ((((var1 >> 2) * (var1 >> 2)) >> 11) *

    (int32_t)dev->calib.par_p6) >> 2;

  var2 = var2 + ((var1 * (int32_t)dev->calib.par_p5) << 1);

  var2 = (var2 >> 2) + ((int32_t)dev->calib.par_p4 << 16);

  var1 = (((((var1 >> 2) * (var1 >> 2)) >> 13) *

    ((int32_t)dev->calib.par_p3 << 5)) >> 3) +

    (((int32_t)dev->calib.par_p2 * var1) >> 1);

  var1 = var1 >> 18;

  var1 = ((32768 + var1) * (int32_t)dev->calib.par_p1) >> 15;

  pressure_comp = 1048576 - pres_adc;

  pressure_comp = (int32_t)((pressure_comp - (var2 >> 12)) * ((uint32_t)3125));

  if (pressure_comp >= BME680_MAX_OVERFLOW_VAL)

    pressure_comp = ((pressure_comp / var1) << 1);

  else

    pressure_comp = ((pressure_comp << 1) / var1);

  var1 = ((int32_t)dev->calib.par_p9 * (int32_t)(((pressure_comp >> 3) *

    (pressure_comp >> 3)) >> 13)) >> 12;

  var2 = ((int32_t)(pressure_comp >> 2) *

    (int32_t)dev->calib.par_p8) >> 13;

  var3 = ((int32_t)(pressure_comp >> 8) * (int32_t)(pressure_comp >> 8) *

    (int32_t)(pressure_comp >> 8) *

    (int32_t)dev->calib.par_p10) >> 17;

  pressure_comp = (int32_t)(pressure_comp) + ((var1 + var2 + var3 +

    ((int32_t)dev->calib.par_p7 << 7)) >> 4);

  return (uint32_t)pressure_comp;

}

/*!

 * @brief This internal API is used to calculate the humidity value.

 */

static uint32_t calc_humidity(uint16_t hum_adc, const struct bme680_dev *dev)

{

  int32_t var1;

  int32_t var2;

  int32_t var3;

  int32_t var4;

  int32_t var5;

  int32_t var6;

  int32_t temp_scaled;

  int32_t calc_hum;

  temp_scaled = (((int32_t) dev->calib.t_fine * 5) + 128) >> 8;

  var1 = (int32_t) (hum_adc - ((int32_t) ((int32_t) dev->calib.par_h1 * 16)))

    - (((temp_scaled * (int32_t) dev->calib.par_h3) / ((int32_t) 100)) >> 1);

  var2 = ((int32_t) dev->calib.par_h2

    * (((temp_scaled * (int32_t) dev->calib.par_h4) / ((int32_t) 100))

      + (((temp_scaled * ((temp_scaled * (int32_t) dev->calib.par_h5) / ((int32_t) 100))) >> 6)

        / ((int32_t) 100)) + (int32_t) (1 << 14))) >> 10;

  var3 = var1 * var2;

  var4 = (int32_t) dev->calib.par_h6 << 7;

  var4 = ((var4) + ((temp_scaled * (int32_t) dev->calib.par_h7) / ((int32_t) 100))) >> 4;

  var5 = ((var3 >> 14) * (var3 >> 14)) >> 10;

  var6 = (var4 * var5) >> 1;

  calc_hum = (((var3 + var6) >> 10) * ((int32_t) 1000)) >> 12;

  if (calc_hum > 100000) /* Cap at 100%rH */

    calc_hum = 100000;

  else if (calc_hum < 0)

    calc_hum = 0;

  return (uint32_t) calc_hum;

}

/*!

 * @brief This internal API is used to calculate the Gas Resistance value.

 */

static uint32_t calc_gas_resistance(uint16_t gas_res_adc, uint8_t gas_range, const struct bme680_dev *dev)

{

  int64_t var1;

  uint64_t var2;

  int64_t var3;

  uint32_t calc_gas_res;

  /**Look up table 1 for the possible gas range values */

  uint32_t lookupTable1[16] = { UINT32_C(2147483647), UINT32_C(2147483647), UINT32_C(2147483647), UINT32_C(2147483647),

    UINT32_C(2147483647), UINT32_C(2126008810), UINT32_C(2147483647), UINT32_C(2130303777),

    UINT32_C(2147483647), UINT32_C(2147483647), UINT32_C(2143188679), UINT32_C(2136746228),

    UINT32_C(2147483647), UINT32_C(2126008810), UINT32_C(2147483647), UINT32_C(2147483647) };

  /**Look up table 2 for the possible gas range values */

  uint32_t lookupTable2[16] = { UINT32_C(4096000000), UINT32_C(2048000000), UINT32_C(1024000000), UINT32_C(512000000),

    UINT32_C(255744255), UINT32_C(127110228), UINT32_C(64000000), UINT32_C(32258064), UINT32_C(16016016),

    UINT32_C(8000000), UINT32_C(4000000), UINT32_C(2000000), UINT32_C(1000000), UINT32_C(500000),

    UINT32_C(250000), UINT32_C(125000) };

  var1 = (int64_t) ((1340 + (5 * (int64_t) dev->calib.range_sw_err)) *

    ((int64_t) lookupTable1[gas_range])) >> 16;

  var2 = (((int64_t) ((int64_t) gas_res_adc << 15) - (int64_t) (16777216)) + var1);

  var3 = (((int64_t) lookupTable2[gas_range] * (int64_t) var1) >> 9);

  calc_gas_res = (uint32_t) ((var3 + ((int64_t) var2 >> 1)) / (int64_t) var2);

  return calc_gas_res;

}