Atsumi Toda / BME280

A modified library for BME280 sensor.

Dependents:   Auto_pilot_prototype_3_2

BME280.cpp@6:7c4db7db09eb, 2020-05-23 (annotated)

Committer:
Joeatsumi
Date:
Sat May 23 13:16:02 2020 +0000
Revision:
6:7c4db7db09eb
Parent:
5:c1f1647004c4 
i2c frequency was changed to 400kHz in .cpp file

Who changed what in which revision?

UserRevisionLine numberNew contents of line
MACRUM 1:763a4018aaec 1 /**
MACRUM 5:c1f1647004c4 2 ******************************************************************************
MACRUM 5:c1f1647004c4 3 * @file BME280.cpp
MACRUM 5:c1f1647004c4 4 * @author Toyomasa Watarai
MACRUM 5:c1f1647004c4 5 * @version V1.0.0
MACRUM 5:c1f1647004c4 6 * @date 11 March 2017
MACRUM 5:c1f1647004c4 7 * @brief BME280 class implementation
MACRUM 5:c1f1647004c4 8 ******************************************************************************
MACRUM 5:c1f1647004c4 9 * @attention
MACRUM 1:763a4018aaec 10 *
MACRUM 5:c1f1647004c4 11 * Permission is hereby granted, free of charge, to any person obtaining a copy
MACRUM 5:c1f1647004c4 12 * of this software and associated documentation files (the "Software"), to deal
MACRUM 5:c1f1647004c4 13 * in the Software without restriction, including without limitation the rights
MACRUM 5:c1f1647004c4 14 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
MACRUM 5:c1f1647004c4 15 * copies of the Software, and to permit persons to whom the Software is
MACRUM 5:c1f1647004c4 16 * furnished to do so, subject to the following conditions:
MACRUM 1:763a4018aaec 17 *
MACRUM 5:c1f1647004c4 18 * The above copyright notice and this permission notice shall be included in
MACRUM 5:c1f1647004c4 19 * all copies or substantial portions of the Software.
MACRUM 1:763a4018aaec 20 *
MACRUM 5:c1f1647004c4 21 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
MACRUM 5:c1f1647004c4 22 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
MACRUM 5:c1f1647004c4 23 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
MACRUM 5:c1f1647004c4 24 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
MACRUM 5:c1f1647004c4 25 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
MACRUM 5:c1f1647004c4 26 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
MACRUM 5:c1f1647004c4 27 * THE SOFTWARE.
MACRUM 1:763a4018aaec 28 */
MACRUM 1:763a4018aaec 29
MACRUM 0:ade9be832910 30 #include "mbed.h"
MACRUM 0:ade9be832910 31 #include "BME280.h"
MACRUM 0:ade9be832910 32
MACRUM 0:ade9be832910 33 BME280::BME280(PinName sda, PinName scl, char slave_adr)
MACRUM 0:ade9be832910 34 :
MACRUM 0:ade9be832910 35 i2c_p(new I2C(sda, scl)),
MACRUM 0:ade9be832910 36 i2c(*i2c_p),
MACRUM 0:ade9be832910 37 address(slave_adr),
MACRUM 0:ade9be832910 38 t_fine(0)
MACRUM 0:ade9be832910 39 {
MACRUM 0:ade9be832910 40 initialize();
MACRUM 0:ade9be832910 41 }
MACRUM 0:ade9be832910 42
MACRUM 0:ade9be832910 43 BME280::BME280(I2C &i2c_obj, char slave_adr)
MACRUM 0:ade9be832910 44 :
MACRUM 0:ade9be832910 45 i2c_p(NULL),
MACRUM 0:ade9be832910 46 i2c(i2c_obj),
MACRUM 0:ade9be832910 47 address(slave_adr),
MACRUM 0:ade9be832910 48 t_fine(0)
MACRUM 0:ade9be832910 49 {
MACRUM 0:ade9be832910 50 initialize();
MACRUM 0:ade9be832910 51 }
MACRUM 0:ade9be832910 52
MACRUM 0:ade9be832910 53 BME280::~BME280()
MACRUM 0:ade9be832910 54 {
MACRUM 0:ade9be832910 55 if (NULL != i2c_p)
MACRUM 0:ade9be832910 56 delete i2c_p;
MACRUM 0:ade9be832910 57 }
Joeatsumi 6:7c4db7db09eb 58
MACRUM 0:ade9be832910 59 void BME280::initialize()
MACRUM 0:ade9be832910 60 {
Joeatsumi 6:7c4db7db09eb 61 //I2C initialization
Joeatsumi 6:7c4db7db09eb 62 i2c.frequency(400000); //400 kHz
Joeatsumi 6:7c4db7db09eb 63
MACRUM 0:ade9be832910 64 char cmd[18];
MACRUM 0:ade9be832910 65
MACRUM 0:ade9be832910 66 cmd[0] = 0xf2; // ctrl_hum
MACRUM 0:ade9be832910 67 cmd[1] = 0x01; // Humidity oversampling x1
MACRUM 0:ade9be832910 68 i2c.write(address, cmd, 2);
MACRUM 0:ade9be832910 69
MACRUM 0:ade9be832910 70 cmd[0] = 0xf4; // ctrl_meas
MACRUM 0:ade9be832910 71 cmd[1] = 0x27; // Temparature oversampling x1, Pressure oversampling x1, Normal mode
MACRUM 0:ade9be832910 72 i2c.write(address, cmd, 2);
MACRUM 0:ade9be832910 73
MACRUM 0:ade9be832910 74 cmd[0] = 0xf5; // config
MACRUM 0:ade9be832910 75 cmd[1] = 0xa0; // Standby 1000ms, Filter off
MACRUM 0:ade9be832910 76 i2c.write(address, cmd, 2);
MACRUM 0:ade9be832910 77
MACRUM 0:ade9be832910 78 cmd[0] = 0x88; // read dig_T regs
MACRUM 0:ade9be832910 79 i2c.write(address, cmd, 1);
MACRUM 0:ade9be832910 80 i2c.read(address, cmd, 6);
MACRUM 0:ade9be832910 81
MACRUM 0:ade9be832910 82 dig_T1 = (cmd[1] << 8) | cmd[0];
MACRUM 0:ade9be832910 83 dig_T2 = (cmd[3] << 8) | cmd[2];
MACRUM 0:ade9be832910 84 dig_T3 = (cmd[5] << 8) | cmd[4];
MACRUM 0:ade9be832910 85
MACRUM 0:ade9be832910 86 DEBUG_PRINT("dig_T = 0x%x, 0x%x, 0x%x\n", dig_T1, dig_T2, dig_T3);
MACRUM 0:ade9be832910 87
MACRUM 0:ade9be832910 88 cmd[0] = 0x8E; // read dig_P regs
MACRUM 0:ade9be832910 89 i2c.write(address, cmd, 1);
MACRUM 0:ade9be832910 90 i2c.read(address, cmd, 18);
MACRUM 0:ade9be832910 91
MACRUM 0:ade9be832910 92 dig_P1 = (cmd[ 1] << 8) | cmd[ 0];
MACRUM 0:ade9be832910 93 dig_P2 = (cmd[ 3] << 8) | cmd[ 2];
MACRUM 0:ade9be832910 94 dig_P3 = (cmd[ 5] << 8) | cmd[ 4];
MACRUM 0:ade9be832910 95 dig_P4 = (cmd[ 7] << 8) | cmd[ 6];
MACRUM 0:ade9be832910 96 dig_P5 = (cmd[ 9] << 8) | cmd[ 8];
MACRUM 0:ade9be832910 97 dig_P6 = (cmd[11] << 8) | cmd[10];
MACRUM 0:ade9be832910 98 dig_P7 = (cmd[13] << 8) | cmd[12];
MACRUM 0:ade9be832910 99 dig_P8 = (cmd[15] << 8) | cmd[14];
MACRUM 0:ade9be832910 100 dig_P9 = (cmd[17] << 8) | cmd[16];
MACRUM 0:ade9be832910 101
MACRUM 0:ade9be832910 102 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 103
MACRUM 0:ade9be832910 104 cmd[0] = 0xA1; // read dig_H regs
MACRUM 0:ade9be832910 105 i2c.write(address, cmd, 1);
MACRUM 2:c35f637c28ef 106 i2c.read(address, cmd, 1);
MACRUM 2:c35f637c28ef 107 cmd[1] = 0xE1; // read dig_H regs
MACRUM 2:c35f637c28ef 108 i2c.write(address, &cmd[1], 1);
MACRUM 2:c35f637c28ef 109 i2c.read(address, &cmd[1], 7);
MACRUM 2:c35f637c28ef 110
MACRUM 0:ade9be832910 111 dig_H1 = cmd[0];
MACRUM 0:ade9be832910 112 dig_H2 = (cmd[2] << 8) | cmd[1];
MACRUM 0:ade9be832910 113 dig_H3 = cmd[3];
MACRUM 0:ade9be832910 114 dig_H4 = (cmd[4] << 4) | (cmd[5] & 0x0f);
MACRUM 2:c35f637c28ef 115 dig_H5 = (cmd[6] << 4) | ((cmd[5]>>4) & 0x0f);
MACRUM 2:c35f637c28ef 116 dig_H6 = cmd[7];
MACRUM 0:ade9be832910 117
MACRUM 0:ade9be832910 118 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 119 }
Joeatsumi 6:7c4db7db09eb 120
MACRUM 0:ade9be832910 121 float BME280::getTemperature()
MACRUM 0:ade9be832910 122 {
MACRUM 0:ade9be832910 123 uint32_t temp_raw;
MACRUM 0:ade9be832910 124 float tempf;
MACRUM 0:ade9be832910 125 char cmd[4];
MACRUM 0:ade9be832910 126
MACRUM 0:ade9be832910 127 cmd[0] = 0xfa; // temp_msb
MACRUM 0:ade9be832910 128 i2c.write(address, cmd, 1);
takafuminaka 3:d4eb81284ea0 129 i2c.read(address, &cmd[1], 3);
MACRUM 0:ade9be832910 130
MACRUM 0:ade9be832910 131 temp_raw = (cmd[1] << 12) | (cmd[2] << 4) | (cmd[3] >> 4);
MACRUM 0:ade9be832910 132
MACRUM 0:ade9be832910 133 int32_t temp;
MACRUM 0:ade9be832910 134
MACRUM 0:ade9be832910 135 temp =
MACRUM 0:ade9be832910 136 (((((temp_raw >> 3) - (dig_T1 << 1))) * dig_T2) >> 11) +
MACRUM 0:ade9be832910 137 ((((((temp_raw >> 4) - dig_T1) * ((temp_raw >> 4) - dig_T1)) >> 12) * dig_T3) >> 14);
MACRUM 0:ade9be832910 138
MACRUM 0:ade9be832910 139 t_fine = temp;
MACRUM 0:ade9be832910 140 temp = (temp * 5 + 128) >> 8;
MACRUM 0:ade9be832910 141 tempf = (float)temp;
MACRUM 0:ade9be832910 142
MACRUM 0:ade9be832910 143 return (tempf/100.0f);
MACRUM 0:ade9be832910 144 }
MACRUM 0:ade9be832910 145
MACRUM 0:ade9be832910 146 float BME280::getPressure()
MACRUM 0:ade9be832910 147 {
MACRUM 0:ade9be832910 148 uint32_t press_raw;
MACRUM 0:ade9be832910 149 float pressf;
MACRUM 0:ade9be832910 150 char cmd[4];
MACRUM 0:ade9be832910 151
MACRUM 0:ade9be832910 152 cmd[0] = 0xf7; // press_msb
MACRUM 0:ade9be832910 153 i2c.write(address, cmd, 1);
takafuminaka 3:d4eb81284ea0 154 i2c.read(address, &cmd[1], 3);
MACRUM 0:ade9be832910 155
MACRUM 0:ade9be832910 156 press_raw = (cmd[1] << 12) | (cmd[2] << 4) | (cmd[3] >> 4);
MACRUM 0:ade9be832910 157
MACRUM 0:ade9be832910 158 int32_t var1, var2;
MACRUM 0:ade9be832910 159 uint32_t press;
MACRUM 0:ade9be832910 160
MACRUM 0:ade9be832910 161 var1 = (t_fine >> 1) - 64000;
MACRUM 0:ade9be832910 162 var2 = (((var1 >> 2) * (var1 >> 2)) >> 11) * dig_P6;
MACRUM 0:ade9be832910 163 var2 = var2 + ((var1 * dig_P5) << 1);
MACRUM 0:ade9be832910 164 var2 = (var2 >> 2) + (dig_P4 << 16);
MACRUM 0:ade9be832910 165 var1 = (((dig_P3 * (((var1 >> 2)*(var1 >> 2)) >> 13)) >> 3) + ((dig_P2 * var1) >> 1)) >> 18;
MACRUM 0:ade9be832910 166 var1 = ((32768 + var1) * dig_P1) >> 15;
MACRUM 0:ade9be832910 167 if (var1 == 0) {
MACRUM 0:ade9be832910 168 return 0;
MACRUM 0:ade9be832910 169 }
MACRUM 0:ade9be832910 170 press = (((1048576 - press_raw) - (var2 >> 12))) * 3125;
MACRUM 0:ade9be832910 171 if(press < 0x80000000) {
MACRUM 0:ade9be832910 172 press = (press << 1) / var1;
MACRUM 0:ade9be832910 173 } else {
MACRUM 0:ade9be832910 174 press = (press / var1) * 2;
MACRUM 0:ade9be832910 175 }
MACRUM 0:ade9be832910 176 var1 = ((int32_t)dig_P9 * ((int32_t)(((press >> 3) * (press >> 3)) >> 13))) >> 12;
MACRUM 0:ade9be832910 177 var2 = (((int32_t)(press >> 2)) * (int32_t)dig_P8) >> 13;
MACRUM 0:ade9be832910 178 press = (press + ((var1 + var2 + dig_P7) >> 4));
MACRUM 0:ade9be832910 179
MACRUM 0:ade9be832910 180 pressf = (float)press;
MACRUM 0:ade9be832910 181 return (pressf/100.0f);
MACRUM 0:ade9be832910 182 }
MACRUM 0:ade9be832910 183
MACRUM 0:ade9be832910 184 float BME280::getHumidity()
MACRUM 0:ade9be832910 185 {
MACRUM 0:ade9be832910 186 uint32_t hum_raw;
MACRUM 0:ade9be832910 187 float humf;
MACRUM 0:ade9be832910 188 char cmd[4];
MACRUM 0:ade9be832910 189
MACRUM 0:ade9be832910 190 cmd[0] = 0xfd; // hum_msb
MACRUM 0:ade9be832910 191 i2c.write(address, cmd, 1);
takafuminaka 3:d4eb81284ea0 192 i2c.read(address, &cmd[1], 2);
MACRUM 0:ade9be832910 193
MACRUM 0:ade9be832910 194 hum_raw = (cmd[1] << 8) | cmd[2];
MACRUM 0:ade9be832910 195
MACRUM 0:ade9be832910 196 int32_t v_x1;
MACRUM 0:ade9be832910 197
MACRUM 0:ade9be832910 198 v_x1 = t_fine - 76800;
MACRUM 0:ade9be832910 199 v_x1 = (((((hum_raw << 14) -(((int32_t)dig_H4) << 20) - (((int32_t)dig_H5) * v_x1)) +
MACRUM 0:ade9be832910 200 ((int32_t)16384)) >> 15) * (((((((v_x1 * (int32_t)dig_H6) >> 10) *
MACRUM 0:ade9be832910 201 (((v_x1 * ((int32_t)dig_H3)) >> 11) + 32768)) >> 10) + 2097152) *
MACRUM 0:ade9be832910 202 (int32_t)dig_H2 + 8192) >> 14));
MACRUM 0:ade9be832910 203 v_x1 = (v_x1 - (((((v_x1 >> 15) * (v_x1 >> 15)) >> 7) * (int32_t)dig_H1) >> 4));
MACRUM 0:ade9be832910 204 v_x1 = (v_x1 < 0 ? 0 : v_x1);
MACRUM 0:ade9be832910 205 v_x1 = (v_x1 > 419430400 ? 419430400 : v_x1);
MACRUM 0:ade9be832910 206
MACRUM 0:ade9be832910 207 humf = (float)(v_x1 >> 12);
MACRUM 0:ade9be832910 208
MACRUM 0:ade9be832910 209 return (humf/1024.0f);
MACRUM 0:ade9be832910 210 }