src/lib/Baro/baro_bmp085.cpp

   1 #if 0 // UNTESTED
   2 #include "baro_bmp085.h"
   3
   4 /****
   5  * Calculations used in this code taken from Adafruit BMP085 calculation
   6  * https://github.com/adafruit/Adafruit-BMP085-Library/blob/master/Adafruit_BMP085.cpp
   7  *
   8  * Code reused under GPL License, see the Adafruit project for full license information
   9  * https://github.com/adafruit/Adafruit-BMP085-Library/
  10  ****/
  11
  12 void BMP085::initialize()
  13 {
  14     if (m_initialized)
  15         return;
  16
  17     // All the calibration registers are in order of our struct and are 2 bytes long too,
  18     // so just read them directly into our calib data
  19     readRegister(BMP085_CALIB_COEFFS_START, (uint8_t *)&m_calib, sizeof(m_calib));
  20 }
  21
  22 uint8_t BMP085::getPressureDuration()
  23 {
  24     switch (OVERSAMPLING_PRESSURE)
  25     {
  26         case 0: return 5; // 4.5ms
  27         case 1: return 8; // 7.5ms
  28         case 2: return 14; // 13.5ms
  29         default: // fallthrough
  30         case 3: return 26; // 25.5ms
  31     }
  32 }
  33
  34 void BMP085::startPressure()
  35 {
  36     uint8_t reg_value = BMP085_CMD_MEAS_PRESSURE | (OVERSAMPLING_PRESSURE << 6);
  37     writeRegister(BMP085_REG_CONTROL, &reg_value, sizeof(reg_value));
  38 }
  39
  40 int32_t BMP085::computeB5(int32_t UT) const
  41 {
  42     int32_t X1 = (UT - (int32_t)m_calib.ac6) * ((int32_t)m_calib.ac5) >> 15;
  43     int32_t X2 = ((int32_t)m_calib.mc << 11) / (X1 + (int32_t)m_calib.md);
  44     return X1 + X2;
  45 }
  46
  47 uint32_t BMP085::getPressure()
  48 {
  49     uint8_t buf[3];
  50     readRegister(BMP085_REG_PRESSURE_DATA, buf, sizeof(buf));
  51     uint32_t raw = ((buf[0] << 16) | (buf[1] << 8) | buf[2]) >> OVERSAMPLING_PRESSURE;
  52
  53     int32_t B3, B5, B6, X1, X2, X3, p;
  54     uint32_t B4, B7;
  55
  56     B5 = computeB5(m_temperatureLast);
  57
  58     B6 = B5 - 4000;
  59     X1 = ((int32_t)m_calib.b2 * ((B6 * B6) >> 12)) >> 11;
  60     X2 = ((int32_t)m_calib.ac2 * B6) >> 11;
  61     X3 = X1 + X2;
  62     B3 = ((((int32_t)m_calib.ac1 * 4 + X3) << OVERSAMPLING_PRESSURE) + 2) / 4;
  63
  64     X1 = ((int32_t)m_calib.ac3 * B6) >> 13;
  65     X2 = ((int32_t)m_calib.b1 * ((B6 * B6) >> 12)) >> 16;
  66     X3 = ((X1 + X2) + 2) >> 2;
  67     B4 = ((uint32_t)m_calib.ac4 * (uint32_t)(X3 + 32768)) >> 15;
  68     B7 = ((uint32_t)raw - B3) * (uint32_t)(50000UL >> OVERSAMPLING_PRESSURE);
  69
  70     if (B7 < 0x80000000) {
  71         p = (B7 * 2) / B4;
  72     } else {
  73         p = (B7 / B4) * 2;
  74     }
  75     X1 = (p >> 8) * (p >> 8);
  76     X1 = (X1 * 3038) >> 16;
  77     X2 = (-7357 * p) >> 16;
  78
  79     p = p + ((X1 + X2 + (int32_t)3791) >> 4);
  80     return p;
  81 }
  82
  83 uint8_t BMP085::getTemperatureDuration()
  84 {
  85     // Max. conversion time 4.5ms
  86     return 5;
  87 }
  88
  89 void BMP085::startTemperature()
  90 {
  91     uint8_t reg_value = BMP085_CMD_MEAS_TEMPERATURE;
  92     writeRegister(BMP085_REG_CONTROL, &reg_value, sizeof(reg_value));
  93 }
  94
  95 int32_t BMP085::getTemperature()
  96 {
  97     m_temperatureLast = 0;
  98     readRegister(BMP085_REG_TEMPERATURE_DATA, (uint8_t *)&m_temperatureLast, sizeof(m_temperatureLast));
  99     return m_temperatureLast;
 100 }
 101
 102 bool BMP085::detect()
 103 {
 104     // Assumes Wire.begin() has already been called
 105     uint8_t chipid = 0;
 106     m_address = BMP085_I2C_ADDR;
 107     readRegister(BMP085_REG_CHIPID, &chipid, sizeof(chipid));
 108     return chipid == BMP085_CHIPID;
 109 }
 110 #endif