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BME280.cpp@0:ade9be832910, 2015-04-06 (annotated)
- Committer:
- MACRUM
- Date:
- Mon Apr 06 09:13:00 2015 +0000
- Revision:
- 0:ade9be832910
- Child:
- 1:763a4018aaec
Initial release
Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
MACRUM | 0:ade9be832910 | 1 | #include "mbed.h" |
MACRUM | 0:ade9be832910 | 2 | #include "BME280.h" |
MACRUM | 0:ade9be832910 | 3 | |
MACRUM | 0:ade9be832910 | 4 | BME280::BME280(PinName sda, PinName scl, char slave_adr) |
MACRUM | 0:ade9be832910 | 5 | : |
MACRUM | 0:ade9be832910 | 6 | i2c_p(new I2C(sda, scl)), |
MACRUM | 0:ade9be832910 | 7 | i2c(*i2c_p), |
MACRUM | 0:ade9be832910 | 8 | address(slave_adr), |
MACRUM | 0:ade9be832910 | 9 | t_fine(0) |
MACRUM | 0:ade9be832910 | 10 | { |
MACRUM | 0:ade9be832910 | 11 | initialize(); |
MACRUM | 0:ade9be832910 | 12 | } |
MACRUM | 0:ade9be832910 | 13 | |
MACRUM | 0:ade9be832910 | 14 | BME280::BME280(I2C &i2c_obj, char slave_adr) |
MACRUM | 0:ade9be832910 | 15 | : |
MACRUM | 0:ade9be832910 | 16 | i2c_p(NULL), |
MACRUM | 0:ade9be832910 | 17 | i2c(i2c_obj), |
MACRUM | 0:ade9be832910 | 18 | address(slave_adr), |
MACRUM | 0:ade9be832910 | 19 | t_fine(0) |
MACRUM | 0:ade9be832910 | 20 | { |
MACRUM | 0:ade9be832910 | 21 | initialize(); |
MACRUM | 0:ade9be832910 | 22 | } |
MACRUM | 0:ade9be832910 | 23 | |
MACRUM | 0:ade9be832910 | 24 | BME280::~BME280() |
MACRUM | 0:ade9be832910 | 25 | { |
MACRUM | 0:ade9be832910 | 26 | if (NULL != i2c_p) |
MACRUM | 0:ade9be832910 | 27 | delete i2c_p; |
MACRUM | 0:ade9be832910 | 28 | } |
MACRUM | 0:ade9be832910 | 29 | |
MACRUM | 0:ade9be832910 | 30 | void BME280::initialize() |
MACRUM | 0:ade9be832910 | 31 | { |
MACRUM | 0:ade9be832910 | 32 | char cmd[18]; |
MACRUM | 0:ade9be832910 | 33 | |
MACRUM | 0:ade9be832910 | 34 | cmd[0] = 0xf2; // ctrl_hum |
MACRUM | 0:ade9be832910 | 35 | cmd[1] = 0x01; // Humidity oversampling x1 |
MACRUM | 0:ade9be832910 | 36 | i2c.write(address, cmd, 2); |
MACRUM | 0:ade9be832910 | 37 | |
MACRUM | 0:ade9be832910 | 38 | cmd[0] = 0xf4; // ctrl_meas |
MACRUM | 0:ade9be832910 | 39 | cmd[1] = 0x27; // Temparature oversampling x1, Pressure oversampling x1, Normal mode |
MACRUM | 0:ade9be832910 | 40 | i2c.write(address, cmd, 2); |
MACRUM | 0:ade9be832910 | 41 | |
MACRUM | 0:ade9be832910 | 42 | cmd[0] = 0xf5; // config |
MACRUM | 0:ade9be832910 | 43 | cmd[1] = 0xa0; // Standby 1000ms, Filter off |
MACRUM | 0:ade9be832910 | 44 | i2c.write(address, cmd, 2); |
MACRUM | 0:ade9be832910 | 45 | |
MACRUM | 0:ade9be832910 | 46 | cmd[0] = 0x88; // read dig_T regs |
MACRUM | 0:ade9be832910 | 47 | i2c.write(address, cmd, 1); |
MACRUM | 0:ade9be832910 | 48 | i2c.read(address, cmd, 6); |
MACRUM | 0:ade9be832910 | 49 | |
MACRUM | 0:ade9be832910 | 50 | dig_T1 = (cmd[1] << 8) | cmd[0]; |
MACRUM | 0:ade9be832910 | 51 | dig_T2 = (cmd[3] << 8) | cmd[2]; |
MACRUM | 0:ade9be832910 | 52 | dig_T3 = (cmd[5] << 8) | cmd[4]; |
MACRUM | 0:ade9be832910 | 53 | |
MACRUM | 0:ade9be832910 | 54 | DEBUG_PRINT("dig_T = 0x%x, 0x%x, 0x%x\n", dig_T1, dig_T2, dig_T3); |
MACRUM | 0:ade9be832910 | 55 | |
MACRUM | 0:ade9be832910 | 56 | cmd[0] = 0x8E; // read dig_P regs |
MACRUM | 0:ade9be832910 | 57 | i2c.write(address, cmd, 1); |
MACRUM | 0:ade9be832910 | 58 | i2c.read(address, cmd, 18); |
MACRUM | 0:ade9be832910 | 59 | |
MACRUM | 0:ade9be832910 | 60 | dig_P1 = (cmd[ 1] << 8) | cmd[ 0]; |
MACRUM | 0:ade9be832910 | 61 | dig_P2 = (cmd[ 3] << 8) | cmd[ 2]; |
MACRUM | 0:ade9be832910 | 62 | dig_P3 = (cmd[ 5] << 8) | cmd[ 4]; |
MACRUM | 0:ade9be832910 | 63 | dig_P4 = (cmd[ 7] << 8) | cmd[ 6]; |
MACRUM | 0:ade9be832910 | 64 | dig_P5 = (cmd[ 9] << 8) | cmd[ 8]; |
MACRUM | 0:ade9be832910 | 65 | dig_P6 = (cmd[11] << 8) | cmd[10]; |
MACRUM | 0:ade9be832910 | 66 | dig_P7 = (cmd[13] << 8) | cmd[12]; |
MACRUM | 0:ade9be832910 | 67 | dig_P8 = (cmd[15] << 8) | cmd[14]; |
MACRUM | 0:ade9be832910 | 68 | dig_P9 = (cmd[17] << 8) | cmd[16]; |
MACRUM | 0:ade9be832910 | 69 | |
MACRUM | 0:ade9be832910 | 70 | DEBUG_PRINT("dig_P = 0x%x, 0x%x, 0x%x, 0x%x, 0x%x, 0x%x, 0x%x, 0x%x, 0x%x\n", dig_P1, dig_P2, dig_P3, dig_P4, dig_P5, dig_P6, dig_P7, dig_P8, dig_P9); |
MACRUM | 0:ade9be832910 | 71 | |
MACRUM | 0:ade9be832910 | 72 | cmd[0] = 0xA1; // read dig_H regs |
MACRUM | 0:ade9be832910 | 73 | i2c.write(address, cmd, 1); |
MACRUM | 0:ade9be832910 | 74 | i2c.read(address, cmd, 9); |
MACRUM | 0:ade9be832910 | 75 | |
MACRUM | 0:ade9be832910 | 76 | dig_H1 = cmd[0]; |
MACRUM | 0:ade9be832910 | 77 | dig_H2 = (cmd[2] << 8) | cmd[1]; |
MACRUM | 0:ade9be832910 | 78 | dig_H3 = cmd[3]; |
MACRUM | 0:ade9be832910 | 79 | dig_H4 = (cmd[4] << 4) | (cmd[5] & 0x0f); |
MACRUM | 0:ade9be832910 | 80 | dig_H5 = (cmd[7] << 4) | ((cmd[6]>>4) & 0x0f); |
MACRUM | 0:ade9be832910 | 81 | dig_H6 = cmd[8]; |
MACRUM | 0:ade9be832910 | 82 | |
MACRUM | 0:ade9be832910 | 83 | DEBUG_PRINT("dig_H = 0x%x, 0x%x, 0x%x, 0x%x, 0x%x, 0x%x\n", dig_H1, dig_H2, dig_H3, dig_H4, dig_H5, dig_H6); |
MACRUM | 0:ade9be832910 | 84 | } |
MACRUM | 0:ade9be832910 | 85 | |
MACRUM | 0:ade9be832910 | 86 | float BME280::getTemperature() |
MACRUM | 0:ade9be832910 | 87 | { |
MACRUM | 0:ade9be832910 | 88 | uint32_t temp_raw; |
MACRUM | 0:ade9be832910 | 89 | float tempf; |
MACRUM | 0:ade9be832910 | 90 | char cmd[4]; |
MACRUM | 0:ade9be832910 | 91 | |
MACRUM | 0:ade9be832910 | 92 | cmd[0] = 0xfa; // temp_msb |
MACRUM | 0:ade9be832910 | 93 | i2c.write(address, cmd, 1); |
MACRUM | 0:ade9be832910 | 94 | i2c.read(address, &cmd[1], 1); |
MACRUM | 0:ade9be832910 | 95 | |
MACRUM | 0:ade9be832910 | 96 | cmd[0] = 0xfb; // temp_lsb |
MACRUM | 0:ade9be832910 | 97 | i2c.write(address, cmd, 1); |
MACRUM | 0:ade9be832910 | 98 | i2c.read(address, &cmd[2], 1); |
MACRUM | 0:ade9be832910 | 99 | |
MACRUM | 0:ade9be832910 | 100 | cmd[0] = 0xfc; // temp_xlsb |
MACRUM | 0:ade9be832910 | 101 | i2c.write(address, cmd, 1); |
MACRUM | 0:ade9be832910 | 102 | i2c.read(address, &cmd[3], 1); |
MACRUM | 0:ade9be832910 | 103 | |
MACRUM | 0:ade9be832910 | 104 | temp_raw = (cmd[1] << 12) | (cmd[2] << 4) | (cmd[3] >> 4); |
MACRUM | 0:ade9be832910 | 105 | |
MACRUM | 0:ade9be832910 | 106 | int32_t temp; |
MACRUM | 0:ade9be832910 | 107 | |
MACRUM | 0:ade9be832910 | 108 | temp = |
MACRUM | 0:ade9be832910 | 109 | (((((temp_raw >> 3) - (dig_T1 << 1))) * dig_T2) >> 11) + |
MACRUM | 0:ade9be832910 | 110 | ((((((temp_raw >> 4) - dig_T1) * ((temp_raw >> 4) - dig_T1)) >> 12) * dig_T3) >> 14); |
MACRUM | 0:ade9be832910 | 111 | |
MACRUM | 0:ade9be832910 | 112 | t_fine = temp; |
MACRUM | 0:ade9be832910 | 113 | temp = (temp * 5 + 128) >> 8; |
MACRUM | 0:ade9be832910 | 114 | tempf = (float)temp; |
MACRUM | 0:ade9be832910 | 115 | |
MACRUM | 0:ade9be832910 | 116 | return (tempf/100.0f); |
MACRUM | 0:ade9be832910 | 117 | } |
MACRUM | 0:ade9be832910 | 118 | |
MACRUM | 0:ade9be832910 | 119 | float BME280::getPressure() |
MACRUM | 0:ade9be832910 | 120 | { |
MACRUM | 0:ade9be832910 | 121 | uint32_t press_raw; |
MACRUM | 0:ade9be832910 | 122 | float pressf; |
MACRUM | 0:ade9be832910 | 123 | char cmd[4]; |
MACRUM | 0:ade9be832910 | 124 | |
MACRUM | 0:ade9be832910 | 125 | cmd[0] = 0xf7; // press_msb |
MACRUM | 0:ade9be832910 | 126 | i2c.write(address, cmd, 1); |
MACRUM | 0:ade9be832910 | 127 | i2c.read(address, &cmd[1], 1); |
MACRUM | 0:ade9be832910 | 128 | |
MACRUM | 0:ade9be832910 | 129 | cmd[0] = 0xf8; // press_lsb |
MACRUM | 0:ade9be832910 | 130 | i2c.write(address, cmd, 1); |
MACRUM | 0:ade9be832910 | 131 | i2c.read(address, &cmd[2], 1); |
MACRUM | 0:ade9be832910 | 132 | |
MACRUM | 0:ade9be832910 | 133 | cmd[0] = 0xf9; // press_xlsb |
MACRUM | 0:ade9be832910 | 134 | i2c.write(address, cmd, 1); |
MACRUM | 0:ade9be832910 | 135 | i2c.read(address, &cmd[3], 1); |
MACRUM | 0:ade9be832910 | 136 | |
MACRUM | 0:ade9be832910 | 137 | press_raw = (cmd[1] << 12) | (cmd[2] << 4) | (cmd[3] >> 4); |
MACRUM | 0:ade9be832910 | 138 | |
MACRUM | 0:ade9be832910 | 139 | int32_t var1, var2; |
MACRUM | 0:ade9be832910 | 140 | uint32_t press; |
MACRUM | 0:ade9be832910 | 141 | |
MACRUM | 0:ade9be832910 | 142 | var1 = (t_fine >> 1) - 64000; |
MACRUM | 0:ade9be832910 | 143 | var2 = (((var1 >> 2) * (var1 >> 2)) >> 11) * dig_P6; |
MACRUM | 0:ade9be832910 | 144 | var2 = var2 + ((var1 * dig_P5) << 1); |
MACRUM | 0:ade9be832910 | 145 | var2 = (var2 >> 2) + (dig_P4 << 16); |
MACRUM | 0:ade9be832910 | 146 | var1 = (((dig_P3 * (((var1 >> 2)*(var1 >> 2)) >> 13)) >> 3) + ((dig_P2 * var1) >> 1)) >> 18; |
MACRUM | 0:ade9be832910 | 147 | var1 = ((32768 + var1) * dig_P1) >> 15; |
MACRUM | 0:ade9be832910 | 148 | if (var1 == 0) { |
MACRUM | 0:ade9be832910 | 149 | return 0; |
MACRUM | 0:ade9be832910 | 150 | } |
MACRUM | 0:ade9be832910 | 151 | press = (((1048576 - press_raw) - (var2 >> 12))) * 3125; |
MACRUM | 0:ade9be832910 | 152 | if(press < 0x80000000) { |
MACRUM | 0:ade9be832910 | 153 | press = (press << 1) / var1; |
MACRUM | 0:ade9be832910 | 154 | } else { |
MACRUM | 0:ade9be832910 | 155 | press = (press / var1) * 2; |
MACRUM | 0:ade9be832910 | 156 | } |
MACRUM | 0:ade9be832910 | 157 | var1 = ((int32_t)dig_P9 * ((int32_t)(((press >> 3) * (press >> 3)) >> 13))) >> 12; |
MACRUM | 0:ade9be832910 | 158 | var2 = (((int32_t)(press >> 2)) * (int32_t)dig_P8) >> 13; |
MACRUM | 0:ade9be832910 | 159 | press = (press + ((var1 + var2 + dig_P7) >> 4)); |
MACRUM | 0:ade9be832910 | 160 | |
MACRUM | 0:ade9be832910 | 161 | pressf = (float)press; |
MACRUM | 0:ade9be832910 | 162 | return (pressf/100.0f); |
MACRUM | 0:ade9be832910 | 163 | } |
MACRUM | 0:ade9be832910 | 164 | |
MACRUM | 0:ade9be832910 | 165 | float BME280::getHumidity() |
MACRUM | 0:ade9be832910 | 166 | { |
MACRUM | 0:ade9be832910 | 167 | uint32_t hum_raw; |
MACRUM | 0:ade9be832910 | 168 | float humf; |
MACRUM | 0:ade9be832910 | 169 | char cmd[4]; |
MACRUM | 0:ade9be832910 | 170 | |
MACRUM | 0:ade9be832910 | 171 | cmd[0] = 0xfd; // hum_msb |
MACRUM | 0:ade9be832910 | 172 | i2c.write(address, cmd, 1); |
MACRUM | 0:ade9be832910 | 173 | i2c.read(address, &cmd[1], 1); |
MACRUM | 0:ade9be832910 | 174 | |
MACRUM | 0:ade9be832910 | 175 | cmd[0] = 0xfd; // hum_lsb |
MACRUM | 0:ade9be832910 | 176 | i2c.write(address, cmd, 1); |
MACRUM | 0:ade9be832910 | 177 | i2c.read(address, &cmd[2], 1); |
MACRUM | 0:ade9be832910 | 178 | |
MACRUM | 0:ade9be832910 | 179 | hum_raw = (cmd[1] << 8) | cmd[2]; |
MACRUM | 0:ade9be832910 | 180 | |
MACRUM | 0:ade9be832910 | 181 | int32_t v_x1; |
MACRUM | 0:ade9be832910 | 182 | |
MACRUM | 0:ade9be832910 | 183 | v_x1 = t_fine - 76800; |
MACRUM | 0:ade9be832910 | 184 | v_x1 = (((((hum_raw << 14) -(((int32_t)dig_H4) << 20) - (((int32_t)dig_H5) * v_x1)) + |
MACRUM | 0:ade9be832910 | 185 | ((int32_t)16384)) >> 15) * (((((((v_x1 * (int32_t)dig_H6) >> 10) * |
MACRUM | 0:ade9be832910 | 186 | (((v_x1 * ((int32_t)dig_H3)) >> 11) + 32768)) >> 10) + 2097152) * |
MACRUM | 0:ade9be832910 | 187 | (int32_t)dig_H2 + 8192) >> 14)); |
MACRUM | 0:ade9be832910 | 188 | v_x1 = (v_x1 - (((((v_x1 >> 15) * (v_x1 >> 15)) >> 7) * (int32_t)dig_H1) >> 4)); |
MACRUM | 0:ade9be832910 | 189 | v_x1 = (v_x1 < 0 ? 0 : v_x1); |
MACRUM | 0:ade9be832910 | 190 | v_x1 = (v_x1 > 419430400 ? 419430400 : v_x1); |
MACRUM | 0:ade9be832910 | 191 | |
MACRUM | 0:ade9be832910 | 192 | humf = (float)(v_x1 >> 12); |
MACRUM | 0:ade9be832910 | 193 | |
MACRUM | 0:ade9be832910 | 194 | return (humf/1024.0f); |
MACRUM | 0:ade9be832910 | 195 | } |