Jon Trinder / BME280

Replaced original getTemperature Routine as it was returned strange values

Dependents:   LPC1768-GPS-FUSION-17102018-1

Fork of BME280 by Toyomasa Watarai

BME280.cpp@5:691e06db489f, 2016-11-29 (annotated)

Committer:
jont
Date:
Tue Nov 29 18:54:29 2016 +0000
Revision:
5:691e06db489f
Parent:
4:ddcaa259e65b 
Replaced original getTemperature Routine as it was returned strange values

Who changed what in which revision?

UserRevisionLine numberNew contents of line
MACRUM 1:763a4018aaec 1 /**
MACRUM 1:763a4018aaec 2 * BME280 Combined humidity and pressure sensor library
MACRUM 1:763a4018aaec 3 *
MACRUM 1:763a4018aaec 4 * @author Toyomasa Watarai
MACRUM 1:763a4018aaec 5 * @version 1.0
MACRUM 1:763a4018aaec 6 * @date 06-April-2015
MACRUM 1:763a4018aaec 7 *
jont 5:691e06db489f 8 * 29 November 2016
jont 5:691e06db489f 9 * Toyomasa Watarai code Modified by jon trinder jont@ninelocks.com
jont 5:691e06db489f 10 * readtemperature routine replaced
jont 5:691e06db489f 11 *
MACRUM 1:763a4018aaec 12 * Library for "BME280 temperature, humidity and pressure sensor module" from Switch Science
MACRUM 1:763a4018aaec 13 * https://www.switch-science.com/catalog/2236/
MACRUM 1:763a4018aaec 14 *
MACRUM 1:763a4018aaec 15 * For more information about the BME280:
takafuminaka 4:ddcaa259e65b 16 * http://ae-bst.resource.bosch.com/media/products/dokumente/bme280/BST-BME280_DS001-10.pdf
MACRUM 1:763a4018aaec 17 */
MACRUM 1:763a4018aaec 18
MACRUM 0:ade9be832910 19 #include "mbed.h"
MACRUM 0:ade9be832910 20 #include "BME280.h"
MACRUM 0:ade9be832910 21
MACRUM 0:ade9be832910 22 BME280::BME280(PinName sda, PinName scl, char slave_adr)
MACRUM 0:ade9be832910 23 :
MACRUM 0:ade9be832910 24 i2c_p(new I2C(sda, scl)),
MACRUM 0:ade9be832910 25 i2c(*i2c_p),
MACRUM 0:ade9be832910 26 address(slave_adr),
MACRUM 0:ade9be832910 27 t_fine(0)
MACRUM 0:ade9be832910 28 {
MACRUM 0:ade9be832910 29 initialize();
MACRUM 0:ade9be832910 30 }
MACRUM 0:ade9be832910 31
MACRUM 0:ade9be832910 32 BME280::BME280(I2C &i2c_obj, char slave_adr)
MACRUM 0:ade9be832910 33 :
MACRUM 0:ade9be832910 34 i2c_p(NULL),
MACRUM 0:ade9be832910 35 i2c(i2c_obj),
MACRUM 0:ade9be832910 36 address(slave_adr),
MACRUM 0:ade9be832910 37 t_fine(0)
MACRUM 0:ade9be832910 38 {
MACRUM 0:ade9be832910 39 initialize();
MACRUM 0:ade9be832910 40 }
MACRUM 0:ade9be832910 41
MACRUM 0:ade9be832910 42 BME280::~BME280()
MACRUM 0:ade9be832910 43 {
MACRUM 0:ade9be832910 44 if (NULL != i2c_p)
MACRUM 0:ade9be832910 45 delete i2c_p;
MACRUM 0:ade9be832910 46 }
MACRUM 0:ade9be832910 47
MACRUM 0:ade9be832910 48 void BME280::initialize()
MACRUM 0:ade9be832910 49 {
MACRUM 0:ade9be832910 50 char cmd[18];
MACRUM 0:ade9be832910 51
MACRUM 0:ade9be832910 52 cmd[0] = 0xf2; // ctrl_hum
MACRUM 0:ade9be832910 53 cmd[1] = 0x01; // Humidity oversampling x1
MACRUM 0:ade9be832910 54 i2c.write(address, cmd, 2);
MACRUM 0:ade9be832910 55
MACRUM 0:ade9be832910 56 cmd[0] = 0xf4; // ctrl_meas
MACRUM 0:ade9be832910 57 cmd[1] = 0x27; // Temparature oversampling x1, Pressure oversampling x1, Normal mode
MACRUM 0:ade9be832910 58 i2c.write(address, cmd, 2);
MACRUM 0:ade9be832910 59
MACRUM 0:ade9be832910 60 cmd[0] = 0xf5; // config
MACRUM 0:ade9be832910 61 cmd[1] = 0xa0; // Standby 1000ms, Filter off
MACRUM 0:ade9be832910 62 i2c.write(address, cmd, 2);
MACRUM 0:ade9be832910 63
MACRUM 0:ade9be832910 64 cmd[0] = 0x88; // read dig_T regs
MACRUM 0:ade9be832910 65 i2c.write(address, cmd, 1);
MACRUM 0:ade9be832910 66 i2c.read(address, cmd, 6);
MACRUM 0:ade9be832910 67
MACRUM 0:ade9be832910 68 dig_T1 = (cmd[1] << 8) | cmd[0];
MACRUM 0:ade9be832910 69 dig_T2 = (cmd[3] << 8) | cmd[2];
MACRUM 0:ade9be832910 70 dig_T3 = (cmd[5] << 8) | cmd[4];
MACRUM 0:ade9be832910 71
MACRUM 0:ade9be832910 72 DEBUG_PRINT("dig_T = 0x%x, 0x%x, 0x%x\n", dig_T1, dig_T2, dig_T3);
MACRUM 0:ade9be832910 73
MACRUM 0:ade9be832910 74 cmd[0] = 0x8E; // read dig_P regs
MACRUM 0:ade9be832910 75 i2c.write(address, cmd, 1);
MACRUM 0:ade9be832910 76 i2c.read(address, cmd, 18);
MACRUM 0:ade9be832910 77
MACRUM 0:ade9be832910 78 dig_P1 = (cmd[ 1] << 8) | cmd[ 0];
MACRUM 0:ade9be832910 79 dig_P2 = (cmd[ 3] << 8) | cmd[ 2];
MACRUM 0:ade9be832910 80 dig_P3 = (cmd[ 5] << 8) | cmd[ 4];
MACRUM 0:ade9be832910 81 dig_P4 = (cmd[ 7] << 8) | cmd[ 6];
MACRUM 0:ade9be832910 82 dig_P5 = (cmd[ 9] << 8) | cmd[ 8];
MACRUM 0:ade9be832910 83 dig_P6 = (cmd[11] << 8) | cmd[10];
MACRUM 0:ade9be832910 84 dig_P7 = (cmd[13] << 8) | cmd[12];
MACRUM 0:ade9be832910 85 dig_P8 = (cmd[15] << 8) | cmd[14];
MACRUM 0:ade9be832910 86 dig_P9 = (cmd[17] << 8) | cmd[16];
MACRUM 0:ade9be832910 87
MACRUM 0:ade9be832910 88 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 89
MACRUM 0:ade9be832910 90 cmd[0] = 0xA1; // read dig_H regs
MACRUM 0:ade9be832910 91 i2c.write(address, cmd, 1);
MACRUM 2:c35f637c28ef 92 i2c.read(address, cmd, 1);
MACRUM 2:c35f637c28ef 93 cmd[1] = 0xE1; // read dig_H regs
MACRUM 2:c35f637c28ef 94 i2c.write(address, &cmd[1], 1);
MACRUM 2:c35f637c28ef 95 i2c.read(address, &cmd[1], 7);
MACRUM 2:c35f637c28ef 96
MACRUM 0:ade9be832910 97 dig_H1 = cmd[0];
MACRUM 0:ade9be832910 98 dig_H2 = (cmd[2] << 8) | cmd[1];
MACRUM 0:ade9be832910 99 dig_H3 = cmd[3];
MACRUM 0:ade9be832910 100 dig_H4 = (cmd[4] << 4) | (cmd[5] & 0x0f);
MACRUM 2:c35f637c28ef 101 dig_H5 = (cmd[6] << 4) | ((cmd[5]>>4) & 0x0f);
MACRUM 2:c35f637c28ef 102 dig_H6 = cmd[7];
MACRUM 0:ade9be832910 103
MACRUM 0:ade9be832910 104 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 105 }
MACRUM 0:ade9be832910 106
jont 5:691e06db489f 107
jont 5:691e06db489f 108 /*
jont 5:691e06db489f 109 As Thomas routine was giving me weird values I rewrote it to look mostly like the adafruit
jont 5:691e06db489f 110 arduino code, which in turn is a lot like the bosch datasheet
jont 5:691e06db489f 111 jon Trinder
jont 5:691e06db489f 112 */
jont 5:691e06db489f 113 /*
MACRUM 0:ade9be832910 114 float BME280::getTemperature()
MACRUM 0:ade9be832910 115 {
MACRUM 0:ade9be832910 116 uint32_t temp_raw;
MACRUM 0:ade9be832910 117 float tempf;
MACRUM 0:ade9be832910 118 char cmd[4];
MACRUM 0:ade9be832910 119
MACRUM 0:ade9be832910 120 cmd[0] = 0xfa; // temp_msb
MACRUM 0:ade9be832910 121 i2c.write(address, cmd, 1);
takafuminaka 3:d4eb81284ea0 122 i2c.read(address, &cmd[1], 3);
MACRUM 0:ade9be832910 123
MACRUM 0:ade9be832910 124 temp_raw = (cmd[1] << 12) | (cmd[2] << 4) | (cmd[3] >> 4);
MACRUM 0:ade9be832910 125
MACRUM 0:ade9be832910 126 int32_t temp;
MACRUM 0:ade9be832910 127
MACRUM 0:ade9be832910 128 temp =
MACRUM 0:ade9be832910 129 (((((temp_raw >> 3) - (dig_T1 << 1))) * dig_T2) >> 11) +
MACRUM 0:ade9be832910 130 ((((((temp_raw >> 4) - dig_T1) * ((temp_raw >> 4) - dig_T1)) >> 12) * dig_T3) >> 14);
MACRUM 0:ade9be832910 131
MACRUM 0:ade9be832910 132 t_fine = temp;
MACRUM 0:ade9be832910 133 temp = (temp * 5 + 128) >> 8;
MACRUM 0:ade9be832910 134 tempf = (float)temp;
MACRUM 0:ade9be832910 135
MACRUM 0:ade9be832910 136 return (tempf/100.0f);
MACRUM 0:ade9be832910 137 }
jont 5:691e06db489f 138 */
jont 5:691e06db489f 139
jont 5:691e06db489f 140 // new version of getTemperature jont@ninelocks.com November 2016
jont 5:691e06db489f 141 float BME280::getTemperature()
jont 5:691e06db489f 142 {
jont 5:691e06db489f 143 int32_t var1, var2, T;
jont 5:691e06db489f 144 int32_t adc_T;
jont 5:691e06db489f 145 float temp_as_float;
jont 5:691e06db489f 146 char cmd[4];
jont 5:691e06db489f 147 cmd[0] = 0xfa; // temp_msb
jont 5:691e06db489f 148 i2c.write(address, cmd, 1);
jont 5:691e06db489f 149 i2c.read(address, &cmd[1], 3);
jont 5:691e06db489f 150
jont 5:691e06db489f 151 //jons slow painful shifting of bits to make it readable
jont 5:691e06db489f 152 adc_T = cmd[1];
jont 5:691e06db489f 153 adc_T <<= 8;
jont 5:691e06db489f 154 adc_T |= cmd[2];
jont 5:691e06db489f 155 adc_T <<= 8;
jont 5:691e06db489f 156 adc_T |= cmd[3];
jont 5:691e06db489f 157
jont 5:691e06db489f 158 //from here more or less same as ada and bosch
jont 5:691e06db489f 159
jont 5:691e06db489f 160 adc_T >>= 4;
jont 5:691e06db489f 161
jont 5:691e06db489f 162 var1 = ((((adc_T>>3) - ((int32_t)dig_T1 <<1))) *
jont 5:691e06db489f 163 ((int32_t)dig_T2)) >> 11;
jont 5:691e06db489f 164
jont 5:691e06db489f 165 var2 = (((((adc_T>>4) - ((int32_t)dig_T1)) *
jont 5:691e06db489f 166 ((adc_T>>4) - ((int32_t)dig_T1))) >> 12) *
jont 5:691e06db489f 167 ((int32_t)dig_T3)) >> 14;
jont 5:691e06db489f 168
jont 5:691e06db489f 169 t_fine = var1 + var2;
jont 5:691e06db489f 170
jont 5:691e06db489f 171 T = (t_fine * 5 + 128) >> 8;
jont 5:691e06db489f 172 temp_as_float = T/100.0;
jont 5:691e06db489f 173 return temp_as_float;
jont 5:691e06db489f 174 }
jont 5:691e06db489f 175
jont 5:691e06db489f 176
MACRUM 0:ade9be832910 177
MACRUM 0:ade9be832910 178 float BME280::getPressure()
MACRUM 0:ade9be832910 179 {
MACRUM 0:ade9be832910 180 uint32_t press_raw;
MACRUM 0:ade9be832910 181 float pressf;
MACRUM 0:ade9be832910 182 char cmd[4];
MACRUM 0:ade9be832910 183
MACRUM 0:ade9be832910 184 cmd[0] = 0xf7; // press_msb
MACRUM 0:ade9be832910 185 i2c.write(address, cmd, 1);
takafuminaka 3:d4eb81284ea0 186 i2c.read(address, &cmd[1], 3);
MACRUM 0:ade9be832910 187
MACRUM 0:ade9be832910 188 press_raw = (cmd[1] << 12) | (cmd[2] << 4) | (cmd[3] >> 4);
MACRUM 0:ade9be832910 189
MACRUM 0:ade9be832910 190 int32_t var1, var2;
MACRUM 0:ade9be832910 191 uint32_t press;
MACRUM 0:ade9be832910 192
MACRUM 0:ade9be832910 193 var1 = (t_fine >> 1) - 64000;
MACRUM 0:ade9be832910 194 var2 = (((var1 >> 2) * (var1 >> 2)) >> 11) * dig_P6;
MACRUM 0:ade9be832910 195 var2 = var2 + ((var1 * dig_P5) << 1);
MACRUM 0:ade9be832910 196 var2 = (var2 >> 2) + (dig_P4 << 16);
MACRUM 0:ade9be832910 197 var1 = (((dig_P3 * (((var1 >> 2)*(var1 >> 2)) >> 13)) >> 3) + ((dig_P2 * var1) >> 1)) >> 18;
MACRUM 0:ade9be832910 198 var1 = ((32768 + var1) * dig_P1) >> 15;
MACRUM 0:ade9be832910 199 if (var1 == 0) {
MACRUM 0:ade9be832910 200 return 0;
MACRUM 0:ade9be832910 201 }
MACRUM 0:ade9be832910 202 press = (((1048576 - press_raw) - (var2 >> 12))) * 3125;
MACRUM 0:ade9be832910 203 if(press < 0x80000000) {
MACRUM 0:ade9be832910 204 press = (press << 1) / var1;
MACRUM 0:ade9be832910 205 } else {
MACRUM 0:ade9be832910 206 press = (press / var1) * 2;
MACRUM 0:ade9be832910 207 }
MACRUM 0:ade9be832910 208 var1 = ((int32_t)dig_P9 * ((int32_t)(((press >> 3) * (press >> 3)) >> 13))) >> 12;
MACRUM 0:ade9be832910 209 var2 = (((int32_t)(press >> 2)) * (int32_t)dig_P8) >> 13;
MACRUM 0:ade9be832910 210 press = (press + ((var1 + var2 + dig_P7) >> 4));
MACRUM 0:ade9be832910 211
MACRUM 0:ade9be832910 212 pressf = (float)press;
MACRUM 0:ade9be832910 213 return (pressf/100.0f);
MACRUM 0:ade9be832910 214 }
MACRUM 0:ade9be832910 215
MACRUM 0:ade9be832910 216 float BME280::getHumidity()
MACRUM 0:ade9be832910 217 {
MACRUM 0:ade9be832910 218 uint32_t hum_raw;
MACRUM 0:ade9be832910 219 float humf;
MACRUM 0:ade9be832910 220 char cmd[4];
MACRUM 0:ade9be832910 221
MACRUM 0:ade9be832910 222 cmd[0] = 0xfd; // hum_msb
MACRUM 0:ade9be832910 223 i2c.write(address, cmd, 1);
takafuminaka 3:d4eb81284ea0 224 i2c.read(address, &cmd[1], 2);
MACRUM 0:ade9be832910 225
MACRUM 0:ade9be832910 226 hum_raw = (cmd[1] << 8) | cmd[2];
MACRUM 0:ade9be832910 227
MACRUM 0:ade9be832910 228 int32_t v_x1;
MACRUM 0:ade9be832910 229
MACRUM 0:ade9be832910 230 v_x1 = t_fine - 76800;
MACRUM 0:ade9be832910 231 v_x1 = (((((hum_raw << 14) -(((int32_t)dig_H4) << 20) - (((int32_t)dig_H5) * v_x1)) +
MACRUM 0:ade9be832910 232 ((int32_t)16384)) >> 15) * (((((((v_x1 * (int32_t)dig_H6) >> 10) *
MACRUM 0:ade9be832910 233 (((v_x1 * ((int32_t)dig_H3)) >> 11) + 32768)) >> 10) + 2097152) *
MACRUM 0:ade9be832910 234 (int32_t)dig_H2 + 8192) >> 14));
MACRUM 0:ade9be832910 235 v_x1 = (v_x1 - (((((v_x1 >> 15) * (v_x1 >> 15)) >> 7) * (int32_t)dig_H1) >> 4));
MACRUM 0:ade9be832910 236 v_x1 = (v_x1 < 0 ? 0 : v_x1);
MACRUM 0:ade9be832910 237 v_x1 = (v_x1 > 419430400 ? 419430400 : v_x1);
MACRUM 0:ade9be832910 238
MACRUM 0:ade9be832910 239 humf = (float)(v_x1 >> 12);
MACRUM 0:ade9be832910 240
MACRUM 0:ade9be832910 241 return (humf/1024.0f);
MACRUM 0:ade9be832910 242 }