Jens Schneider / BME280

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BME280.cpp@0:6b0de3ad5900, 2015-11-07 (annotated)

Committer:
jenschn
Date:
Sat Nov 07 12:04:40 2015 +0000
Revision:
0:6b0de3ad5900
Child:
1:d766e0ac711f
Bosch BME280 I2C driver

Who changed what in which revision?

UserRevisionLine numberNew contents of line
jenschn 0:6b0de3ad5900 1 /*****************************************************************************
jenschn 0:6b0de3ad5900 2 * *
jenschn 0:6b0de3ad5900 3 * BOSCH BME208 Temperature Pressure Humidity Sensor Driver *
jenschn 0:6b0de3ad5900 4 * *
jenschn 0:6b0de3ad5900 5 * (c) 2015 Jens Schneider *
jenschn 0:6b0de3ad5900 6 * mailto:jens.schneider@kaust.edu.sa *
jenschn 0:6b0de3ad5900 7 * Visual Computing Center (VCC) *
jenschn 0:6b0de3ad5900 8 * King Abdullah University of Science and Technology (KAUST) *
jenschn 0:6b0de3ad5900 9 * 4700 Thuwal, Kingdom of Saudi Arabia *
jenschn 0:6b0de3ad5900 10 * *
jenschn 0:6b0de3ad5900 11 * PERMISSION GRANTED TO USE IN NON-COMMERCIAL AND EDUCATIONAL PROJECTS *
jenschn 0:6b0de3ad5900 12 * NO RESPONSIBILITY ASSUMED FOR DAMAGE OR LOSS OF ANY HARDWARE OR SOFTWARE *
jenschn 0:6b0de3ad5900 13 * *
jenschn 0:6b0de3ad5900 14 * version 0.1 *
jenschn 0:6b0de3ad5900 15 * last change 07.Nov.2015 *
jenschn 0:6b0de3ad5900 16 * *
jenschn 0:6b0de3ad5900 17 *****************************************************************************/
jenschn 0:6b0de3ad5900 18 #include"BME280.h"
jenschn 0:6b0de3ad5900 19
jenschn 0:6b0de3ad5900 20 const uint8_t BME280::REG_HUM_LSB = 0xFE;
jenschn 0:6b0de3ad5900 21 const uint8_t BME280::REG_HUM_MSB = 0xFD;
jenschn 0:6b0de3ad5900 22 const uint8_t BME280::REG_TEMP_XLSB = 0xFC;
jenschn 0:6b0de3ad5900 23 const uint8_t BME280::REG_TEMP_LSB = 0xFB;
jenschn 0:6b0de3ad5900 24 const uint8_t BME280::REG_TEMP_MSB = 0xFA;
jenschn 0:6b0de3ad5900 25 const uint8_t BME280::REG_PRESS_XLSB = 0xF9;
jenschn 0:6b0de3ad5900 26 const uint8_t BME280::REG_PRESS_LSB = 0xF8;
jenschn 0:6b0de3ad5900 27 const uint8_t BME280::REG_PRESS_MSB = 0xF7;
jenschn 0:6b0de3ad5900 28
jenschn 0:6b0de3ad5900 29 const uint8_t BME280::REG_CONFIG = 0xF5;
jenschn 0:6b0de3ad5900 30 const uint8_t BME280::REG_CTRL_MEAS = 0xF4;
jenschn 0:6b0de3ad5900 31 const uint8_t BME280::REG_STATUS = 0xF4;
jenschn 0:6b0de3ad5900 32 const uint8_t BME280::REG_CTRL_HUM = 0xF3;
jenschn 0:6b0de3ad5900 33 const uint8_t BME280::REG_CALIB26_41_BASE = 0xE1;
jenschn 0:6b0de3ad5900 34 const uint8_t BME280::REG_RESET = 0xE0;
jenschn 0:6b0de3ad5900 35 const uint8_t BME280::REG_ID = 0xD0;
jenschn 0:6b0de3ad5900 36 const uint8_t BME280::REG_CALIB00_25_BASE = 0x88;
jenschn 0:6b0de3ad5900 37
jenschn 0:6b0de3ad5900 38 const uint8_t BME280::VAL_CALIB26_41_SIZE = 0x10;
jenschn 0:6b0de3ad5900 39 const uint8_t BME280::VAL_CALIB00_25_SIZE = 0x1A;
jenschn 0:6b0de3ad5900 40 const uint8_t BME280::VAL_CHIP_ID = 0x60;
jenschn 0:6b0de3ad5900 41 const uint8_t BME280::VAL_RESET = 0xB6;
jenschn 0:6b0de3ad5900 42
jenschn 0:6b0de3ad5900 43 const uint8_t BME280::STATUS_IDLE = 0x00;
jenschn 0:6b0de3ad5900 44 const uint8_t BME280::STATUS_MEASURING = 0x08;
jenschn 0:6b0de3ad5900 45 const uint8_t BME280::STATUS_UPDATING = 0x01;
jenschn 0:6b0de3ad5900 46 const uint8_t BME280::STATUS_ERROR = 0xFF;
jenschn 0:6b0de3ad5900 47
jenschn 0:6b0de3ad5900 48 extern Serial ser;
jenschn 0:6b0de3ad5900 49
jenschn 0:6b0de3ad5900 50 BME280::BME280(void) : m_pI2C(NULL), m_address(0x00), m_fine_temp(0x1F3E6), m_mode(MODE_SLEEP) {
jenschn 0:6b0de3ad5900 51 // initialized m_fine_temp to 25C
jenschn 0:6b0de3ad5900 52 }
jenschn 0:6b0de3ad5900 53
jenschn 0:6b0de3ad5900 54 BME280::~BME280(void) {
jenschn 0:6b0de3ad5900 55 done();
jenschn 0:6b0de3ad5900 56 }
jenschn 0:6b0de3ad5900 57
jenschn 0:6b0de3ad5900 58 bool BME280::init(I2C& i2c, uint8_t address) {
jenschn 0:6b0de3ad5900 59 m_pI2C = &i2c;
jenschn 0:6b0de3ad5900 60 m_address = address<<1;
jenschn 0:6b0de3ad5900 61 m_fine_temp = 0x1F3E6;
jenschn 0:6b0de3ad5900 62 if (!reset()) return false;
jenschn 0:6b0de3ad5900 63 if (read_chip_id()!=0x60) return false;
jenschn 0:6b0de3ad5900 64 if (!read_calibration()) return false;
jenschn 0:6b0de3ad5900 65 return true;
jenschn 0:6b0de3ad5900 66 }
jenschn 0:6b0de3ad5900 67
jenschn 0:6b0de3ad5900 68 bool BME280::done(void) {
jenschn 0:6b0de3ad5900 69 stop();
jenschn 0:6b0de3ad5900 70 m_pI2C = NULL;
jenschn 0:6b0de3ad5900 71 m_address = 0x00;
jenschn 0:6b0de3ad5900 72 m_mode = MODE_SLEEP;
jenschn 0:6b0de3ad5900 73 return true;
jenschn 0:6b0de3ad5900 74 }
jenschn 0:6b0de3ad5900 75
jenschn 0:6b0de3ad5900 76
jenschn 0:6b0de3ad5900 77 bool BME280::start( BME280::sampling_t hum,
jenschn 0:6b0de3ad5900 78 BME280::sampling_t temp,
jenschn 0:6b0de3ad5900 79 BME280::sampling_t press,
jenschn 0:6b0de3ad5900 80 BME280::standby_t standby,
jenschn 0:6b0de3ad5900 81 BME280::filter_t filter,
jenschn 0:6b0de3ad5900 82 BME280::mode_t mode) {
jenschn 0:6b0de3ad5900 83 // 1. Reset
jenschn 0:6b0de3ad5900 84 if (!reset()) return false;
jenschn 0:6b0de3ad5900 85
jenschn 0:6b0de3ad5900 86 // 2. Write CONFIG
jenschn 0:6b0de3ad5900 87 uint8_t val_cfg = uint8_t(standby)<<5;
jenschn 0:6b0de3ad5900 88 val_cfg|=uint8_t(filter)<<2;
jenschn 0:6b0de3ad5900 89 if (!write8(REG_CONFIG,val_cfg)) return false;
jenschn 0:6b0de3ad5900 90
jenschn 0:6b0de3ad5900 91 // 3. Write CTRL_HUM
jenschn 0:6b0de3ad5900 92 if (!write8(REG_CTRL_HUM,uint8_t(hum))) return false;
jenschn 0:6b0de3ad5900 93
jenschn 0:6b0de3ad5900 94 // 4. Write CTRL_MEAS
jenschn 0:6b0de3ad5900 95 uint8_t val_meas = uint8_t(temp)<<5;
jenschn 0:6b0de3ad5900 96 val_meas |= uint8_t(press)<<2;
jenschn 0:6b0de3ad5900 97 val_meas |= uint8_t(mode);
jenschn 0:6b0de3ad5900 98 if (!write8(REG_CTRL_MEAS,val_meas)) return false;
jenschn 0:6b0de3ad5900 99
jenschn 0:6b0de3ad5900 100 m_mode = mode;
jenschn 0:6b0de3ad5900 101
jenschn 0:6b0de3ad5900 102 return true;
jenschn 0:6b0de3ad5900 103 }
jenschn 0:6b0de3ad5900 104
jenschn 0:6b0de3ad5900 105 bool BME280::stop(void) {
jenschn 0:6b0de3ad5900 106 return reset();
jenschn 0:6b0de3ad5900 107 }
jenschn 0:6b0de3ad5900 108
jenschn 0:6b0de3ad5900 109 bool BME280::get(float& temperature, float& pressure, float& humidity) {
jenschn 0:6b0de3ad5900 110 int32_t T;
jenschn 0:6b0de3ad5900 111 uint32_t P, H;
jenschn 0:6b0de3ad5900 112 if (!get(T,P,H)) return false;
jenschn 0:6b0de3ad5900 113 temperature = float(T)*0.01f; // in degree C
jenschn 0:6b0de3ad5900 114 pressure = 0.01f*(float(P)/256.0f); // in hPa / mbar
jenschn 0:6b0de3ad5900 115 humidity = float(H)/1024.0f; // in %
jenschn 0:6b0de3ad5900 116 return true;
jenschn 0:6b0de3ad5900 117 }
jenschn 0:6b0de3ad5900 118
jenschn 0:6b0de3ad5900 119 bool BME280::get(int32_t& temperature, uint32_t& pressure, uint32_t& humidity) {
jenschn 0:6b0de3ad5900 120 if (m_mode!=MODE_AUTO) {
jenschn 0:6b0de3ad5900 121 // Trigger forced conversion by updating CTRL_MEAS register
jenschn 0:6b0de3ad5900 122 uint8_t val = 0x00;
jenschn 0:6b0de3ad5900 123 if (!read8(REG_CTRL_MEAS,val)) return false;
jenschn 0:6b0de3ad5900 124 val = (val&0xFC)|uint8_t(MODE_FORCED);
jenschn 0:6b0de3ad5900 125 if (!write8(REG_CTRL_MEAS,val)) return false;
jenschn 0:6b0de3ad5900 126 // Wait for measurement to finish
jenschn 0:6b0de3ad5900 127 do {
jenschn 0:6b0de3ad5900 128 val = read_status();
jenschn 0:6b0de3ad5900 129 if ((val&STATUS_MEASURING)!=0) wait_ms(1);
jenschn 0:6b0de3ad5900 130 } while(val&STATUS_MEASURING);
jenschn 0:6b0de3ad5900 131 }
jenschn 0:6b0de3ad5900 132 int32_t rawT, rawP, rawH;
jenschn 0:6b0de3ad5900 133 if (!raw_data(rawT,rawP,rawH)) return false;
jenschn 0:6b0de3ad5900 134 temperature = compensate_T(rawT);
jenschn 0:6b0de3ad5900 135 pressure = compensate_P(rawP);
jenschn 0:6b0de3ad5900 136 humidity = compensate_H(rawH);
jenschn 0:6b0de3ad5900 137 return true;
jenschn 0:6b0de3ad5900 138 }
jenschn 0:6b0de3ad5900 139
jenschn 0:6b0de3ad5900 140 bool BME280::raw_data(int32_t& rawT, int32_t& rawP, int32_t& rawH) {
jenschn 0:6b0de3ad5900 141 if (m_pI2C==NULL) return false;
jenschn 0:6b0de3ad5900 142 uint8_t data[8];
jenschn 0:6b0de3ad5900 143 uint8_t ok = 0x00;
jenschn 0:6b0de3ad5900 144 m_pI2C->start();
jenschn 0:6b0de3ad5900 145 ok = (ok<<1)|m_pI2C->write(m_address);
jenschn 0:6b0de3ad5900 146 ok = (ok<<1)|m_pI2C->write(REG_PRESS_MSB);
jenschn 0:6b0de3ad5900 147 m_pI2C->start();
jenschn 0:6b0de3ad5900 148 ok = (ok<<1)|m_pI2C->write(m_address|1);
jenschn 0:6b0de3ad5900 149 for (int i=0; i<7; i++) data[i] = m_pI2C->read(1);
jenschn 0:6b0de3ad5900 150 data[7] = m_pI2C->read(0);
jenschn 0:6b0de3ad5900 151 m_pI2C->stop();
jenschn 0:6b0de3ad5900 152 if (ok!=0x7) {
jenschn 0:6b0de3ad5900 153 rawT = rawP = rawH = 0x00;
jenschn 0:6b0de3ad5900 154 return false;
jenschn 0:6b0de3ad5900 155 }
jenschn 0:6b0de3ad5900 156 rawP = (int32_t(data[0])<<12)|(int32_t(data[1])<<4)|(int32_t(data[2])>>4);
jenschn 0:6b0de3ad5900 157 rawT = (int32_t(data[3])<<12)|(int32_t(data[4])<<4)|(int32_t(data[5])>>4);
jenschn 0:6b0de3ad5900 158 rawH = (int32_t(data[6])<<8)|int32_t(data[7]);
jenschn 0:6b0de3ad5900 159 return true;
jenschn 0:6b0de3ad5900 160 }
jenschn 0:6b0de3ad5900 161
jenschn 0:6b0de3ad5900 162
jenschn 0:6b0de3ad5900 163 int16_t BME280::conv_s16(const uint8_t* data, int lo, int hi) const {
jenschn 0:6b0de3ad5900 164 return int16_t(uint16_t(data[lo])|(uint16_t(data[hi])<<8));
jenschn 0:6b0de3ad5900 165 }
jenschn 0:6b0de3ad5900 166
jenschn 0:6b0de3ad5900 167 uint16_t BME280::conv_u16(const uint8_t* data, int lo, int hi) const {
jenschn 0:6b0de3ad5900 168 return uint16_t(data[lo])|(uint16_t(data[hi])<<8);
jenschn 0:6b0de3ad5900 169 }
jenschn 0:6b0de3ad5900 170
jenschn 0:6b0de3ad5900 171 bool BME280::read_calibration(void) {
jenschn 0:6b0de3ad5900 172 if (m_pI2C==NULL) return false;
jenschn 0:6b0de3ad5900 173 return read_calibration_lo() && read_calibration_hi();
jenschn 0:6b0de3ad5900 174 }
jenschn 0:6b0de3ad5900 175
jenschn 0:6b0de3ad5900 176 bool BME280::read_calibration_lo(void) {
jenschn 0:6b0de3ad5900 177 uint8_t data[VAL_CALIB00_25_SIZE];
jenschn 0:6b0de3ad5900 178 if (m_pI2C==NULL) return false;
jenschn 0:6b0de3ad5900 179 uint8_t ok = 0x00;
jenschn 0:6b0de3ad5900 180 m_pI2C->start();
jenschn 0:6b0de3ad5900 181 ok = (ok<<1)|m_pI2C->write(m_address);
jenschn 0:6b0de3ad5900 182 ok = (ok<<1)|m_pI2C->write(REG_CALIB00_25_BASE);
jenschn 0:6b0de3ad5900 183 m_pI2C->start();
jenschn 0:6b0de3ad5900 184 ok = (ok<<1)|m_pI2C->write(m_address|1);
jenschn 0:6b0de3ad5900 185 for (int n=0; n<VAL_CALIB00_25_SIZE-1; n++) data[n] = m_pI2C->read(1);
jenschn 0:6b0de3ad5900 186 data[VAL_CALIB00_25_SIZE-1] = m_pI2C->read(0);
jenschn 0:6b0de3ad5900 187 m_pI2C->stop();
jenschn 0:6b0de3ad5900 188 if (ok!=0x7) return false;
jenschn 0:6b0de3ad5900 189
jenschn 0:6b0de3ad5900 190 m_calib.dig_T1 = conv_u16(data,0,1); // 0x88:89
jenschn 0:6b0de3ad5900 191 m_calib.dig_T2 = conv_s16(data,2,3); // 0x8A:8B
jenschn 0:6b0de3ad5900 192 m_calib.dig_T3 = conv_s16(data,4,5); // 0x8C:8D
jenschn 0:6b0de3ad5900 193 m_calib.dig_P1 = conv_u16(data,6,7); // 0x8E:8F
jenschn 0:6b0de3ad5900 194 m_calib.dig_P2 = conv_s16(data,8,9); // 0x90:91
jenschn 0:6b0de3ad5900 195 m_calib.dig_P3 = conv_s16(data,10,11); // 0x92:93
jenschn 0:6b0de3ad5900 196 m_calib.dig_P4 = conv_s16(data,12,13); // 0x94:95
jenschn 0:6b0de3ad5900 197 m_calib.dig_P5 = conv_s16(data,14,15); // 0x96:97
jenschn 0:6b0de3ad5900 198 m_calib.dig_P6 = conv_s16(data,16,17); // 0x98:99
jenschn 0:6b0de3ad5900 199 m_calib.dig_P7 = conv_s16(data,18,19); // 0x9A:9B
jenschn 0:6b0de3ad5900 200 m_calib.dig_P8 = conv_s16(data,20,21); // 0x9C:9D
jenschn 0:6b0de3ad5900 201 m_calib.dig_P9 = conv_s16(data,22,23); // 0x9E:9F
jenschn 0:6b0de3ad5900 202 // 0xA0
jenschn 0:6b0de3ad5900 203 m_calib.dig_H1 = data[25]; // 0xA1
jenschn 0:6b0de3ad5900 204 return true;
jenschn 0:6b0de3ad5900 205 }
jenschn 0:6b0de3ad5900 206
jenschn 0:6b0de3ad5900 207 bool BME280::read_calibration_hi(void) {
jenschn 0:6b0de3ad5900 208 uint8_t data[VAL_CALIB26_41_SIZE];
jenschn 0:6b0de3ad5900 209 if (m_pI2C==NULL) return false;
jenschn 0:6b0de3ad5900 210 uint8_t ok = 0x00;
jenschn 0:6b0de3ad5900 211 m_pI2C->start();
jenschn 0:6b0de3ad5900 212 ok = (ok<<1)|m_pI2C->write(m_address);
jenschn 0:6b0de3ad5900 213 ok = (ok<<1)|m_pI2C->write(REG_CALIB26_41_BASE);
jenschn 0:6b0de3ad5900 214 m_pI2C->start();
jenschn 0:6b0de3ad5900 215 ok = (ok<<1)|m_pI2C->write(m_address|1);
jenschn 0:6b0de3ad5900 216 for (int n=0; n<VAL_CALIB26_41_SIZE-1; n++) data[n] = m_pI2C->read(1);
jenschn 0:6b0de3ad5900 217 data[VAL_CALIB26_41_SIZE-1] = m_pI2C->read(0);
jenschn 0:6b0de3ad5900 218 m_pI2C->stop();
jenschn 0:6b0de3ad5900 219 if (ok!=0x7) return false;
jenschn 0:6b0de3ad5900 220
jenschn 0:6b0de3ad5900 221 m_calib.dig_H2 = conv_s16(data,0,1); // 0xE1:E2
jenschn 0:6b0de3ad5900 222 m_calib.dig_H3 = data[2]; // 0xE3
jenschn 0:6b0de3ad5900 223 m_calib.dig_H4 = int16_t((uint16_t(data[3])<<8)|uint16_t((data[4]&0xF)<<4))>>4; // 0xE4:E5[3:0]
jenschn 0:6b0de3ad5900 224 m_calib.dig_H5 = int16_t((uint16_t(data[5])<<8)|uint16_t((data[4]&0xF0))>>4); // 0xE5[7:4]:E6
jenschn 0:6b0de3ad5900 225 m_calib.dig_H6 = int8_t(data[6]); // 0xE7
jenschn 0:6b0de3ad5900 226 return true;
jenschn 0:6b0de3ad5900 227 }
jenschn 0:6b0de3ad5900 228
jenschn 0:6b0de3ad5900 229 int32_t BME280::compensate_T(int32_t raw_T) {
jenschn 0:6b0de3ad5900 230 int32_t var1, var2, T;
jenschn 0:6b0de3ad5900 231 var1 = ((((raw_T>>3) - ((int32_t)m_calib.dig_T1<<1))) * ((int32_t)m_calib.dig_T2)) >> 11;
jenschn 0:6b0de3ad5900 232 var2 = (((((raw_T>>4) - ((int32_t)m_calib.dig_T1)) * ((raw_T>>4) - ((int32_t)m_calib.dig_T1))) >> 12) * ((int32_t)m_calib.dig_T3)) >> 14;
jenschn 0:6b0de3ad5900 233 m_fine_temp = var1 + var2;
jenschn 0:6b0de3ad5900 234 T = (m_fine_temp * 5 + 128) >> 8;
jenschn 0:6b0de3ad5900 235 return T;
jenschn 0:6b0de3ad5900 236 }
jenschn 0:6b0de3ad5900 237
jenschn 0:6b0de3ad5900 238 uint32_t BME280::compensate_P(int32_t raw_P) {
jenschn 0:6b0de3ad5900 239 int64_t var1, var2, p;
jenschn 0:6b0de3ad5900 240 var1 = ((int64_t)m_fine_temp) - 128000;
jenschn 0:6b0de3ad5900 241 var2 = var1 * var1 * (int64_t)m_calib.dig_P6;
jenschn 0:6b0de3ad5900 242 var2 = var2 + ((var1*(int64_t)m_calib.dig_P5)<<17);
jenschn 0:6b0de3ad5900 243 var2 = var2 + (((int64_t)m_calib.dig_P4)<<35);
jenschn 0:6b0de3ad5900 244 var1 = ((var1 * var1 * (int64_t)m_calib.dig_P3)>>8) + ((var1 * (int64_t)m_calib.dig_P2)<<12);
jenschn 0:6b0de3ad5900 245 var1 = (((((int64_t)1)<<47)+var1))*((int64_t)m_calib.dig_P1)>>33;
jenschn 0:6b0de3ad5900 246 if (var1 == 0) return false; // avoid division by zero
jenschn 0:6b0de3ad5900 247 p = 1048576-raw_P;
jenschn 0:6b0de3ad5900 248 p = (((p<<31)-var2)*3125)/var1;
jenschn 0:6b0de3ad5900 249 var1 = (((int64_t)m_calib.dig_P9) * (p>>13) * (p>>13)) >> 25;
jenschn 0:6b0de3ad5900 250 var2 = (((int64_t)m_calib.dig_P8) * p) >> 19;
jenschn 0:6b0de3ad5900 251 p = ((p + var1 + var2) >> 8) + (((int64_t)m_calib.dig_P7)<<4);
jenschn 0:6b0de3ad5900 252 return (uint32_t)p;
jenschn 0:6b0de3ad5900 253 }
jenschn 0:6b0de3ad5900 254
jenschn 0:6b0de3ad5900 255 uint32_t BME280::compensate_H(int32_t raw_H) {
jenschn 0:6b0de3ad5900 256 int32_t v_x1_u32r;
jenschn 0:6b0de3ad5900 257 v_x1_u32r = (m_fine_temp - ((int32_t)76800));
jenschn 0:6b0de3ad5900 258 v_x1_u32r = (((((raw_H << 14) - (((int32_t)m_calib.dig_H4) << 20) - (((int32_t)m_calib.dig_H5) * v_x1_u32r)) +
jenschn 0:6b0de3ad5900 259 ((int32_t)16384)) >> 15) * (((((((v_x1_u32r * ((int32_t)m_calib.dig_H6)) >> 10) * (((v_x1_u32r *
jenschn 0:6b0de3ad5900 260 ((int32_t)m_calib.dig_H3)) >> 11) + ((int32_t)32768))) >> 10) + ((int32_t)2097152)) *
jenschn 0:6b0de3ad5900 261 ((int32_t)m_calib.dig_H2) + 8192) >> 14));
jenschn 0:6b0de3ad5900 262 v_x1_u32r = (v_x1_u32r - (((((v_x1_u32r >> 15) * (v_x1_u32r >> 15)) >> 7) * ((int32_t)m_calib.dig_H1)) >> 4));
jenschn 0:6b0de3ad5900 263 v_x1_u32r = (v_x1_u32r < 0 ? 0 : v_x1_u32r);
jenschn 0:6b0de3ad5900 264 v_x1_u32r = (v_x1_u32r > 419430400 ? 419430400 : v_x1_u32r);
jenschn 0:6b0de3ad5900 265 return (uint32_t)(v_x1_u32r>>12);
jenschn 0:6b0de3ad5900 266 }
jenschn 0:6b0de3ad5900 267
jenschn 0:6b0de3ad5900 268 // ======================================== LOW LEVEL API ========================================
jenschn 0:6b0de3ad5900 269 bool BME280::reset(void) {
jenschn 0:6b0de3ad5900 270 if (write8(REG_RESET,VAL_RESET)) {
jenschn 0:6b0de3ad5900 271 wait_ms(2);
jenschn 0:6b0de3ad5900 272 m_mode = MODE_SLEEP;
jenschn 0:6b0de3ad5900 273 return true;
jenschn 0:6b0de3ad5900 274 }
jenschn 0:6b0de3ad5900 275 return false;
jenschn 0:6b0de3ad5900 276 }
jenschn 0:6b0de3ad5900 277
jenschn 0:6b0de3ad5900 278 uint8_t BME280::read_chip_id(void) {
jenschn 0:6b0de3ad5900 279 uint8_t result;
jenschn 0:6b0de3ad5900 280 if (read8(REG_ID,result)) return result;
jenschn 0:6b0de3ad5900 281 else return 0x00;
jenschn 0:6b0de3ad5900 282 }
jenschn 0:6b0de3ad5900 283
jenschn 0:6b0de3ad5900 284 uint8_t BME280::read_status(void) {
jenschn 0:6b0de3ad5900 285 uint8_t result;
jenschn 0:6b0de3ad5900 286 if (read8(REG_STATUS,result)) return result&0x9;
jenschn 0:6b0de3ad5900 287 else return STATUS_ERROR;
jenschn 0:6b0de3ad5900 288 }
jenschn 0:6b0de3ad5900 289
jenschn 0:6b0de3ad5900 290 bool BME280::read8(uint8_t reg, uint8_t& val) {
jenschn 0:6b0de3ad5900 291 if (m_pI2C==NULL) return false;
jenschn 0:6b0de3ad5900 292 uint8_t ok = 0x00;
jenschn 0:6b0de3ad5900 293 val = 0x00;
jenschn 0:6b0de3ad5900 294 m_pI2C->start();
jenschn 0:6b0de3ad5900 295 m_pI2C->start();
jenschn 0:6b0de3ad5900 296 ok = (ok<<1)|m_pI2C->write(m_address);
jenschn 0:6b0de3ad5900 297 ok = (ok<<1)|m_pI2C->write(reg);
jenschn 0:6b0de3ad5900 298 m_pI2C->start();
jenschn 0:6b0de3ad5900 299 ok = (ok<<1)|m_pI2C->write(m_address|1);
jenschn 0:6b0de3ad5900 300 val = m_pI2C->read(0);
jenschn 0:6b0de3ad5900 301 m_pI2C->stop();
jenschn 0:6b0de3ad5900 302 return ok==0x7;
jenschn 0:6b0de3ad5900 303 }
jenschn 0:6b0de3ad5900 304
jenschn 0:6b0de3ad5900 305 bool BME280::write8(uint8_t reg, uint8_t val) {
jenschn 0:6b0de3ad5900 306 if (m_pI2C==NULL) return false;
jenschn 0:6b0de3ad5900 307 uint8_t ok = 0x00;
jenschn 0:6b0de3ad5900 308 m_pI2C->start();
jenschn 0:6b0de3ad5900 309 ok = (ok<<1)|m_pI2C->write(m_address);
jenschn 0:6b0de3ad5900 310 ok = (ok<<1)|m_pI2C->write(reg);
jenschn 0:6b0de3ad5900 311 ok = (ok<<1)|m_pI2C->write(val);
jenschn 0:6b0de3ad5900 312 m_pI2C->stop();
jenschn 0:6b0de3ad5900 313 return ok==0x7;
jenschn 0:6b0de3ad5900 314 }
jenschn 0:6b0de3ad5900 315
jenschn 0:6b0de3ad5900 316 const BME280::calib_t& BME280::calib(void) const {
jenschn 0:6b0de3ad5900 317 return m_calib;
jenschn 0:6b0de3ad5900 318 }