Daniel David / BMP280

Pressure and temperature sensor based on BMP280

Dependents:   weather_station_proj weather_station_project weather_station_proj_v1_2

Fork of BMP280 by Karl Zweimüller

BMP280.cpp@9:3a0af995dd4c, 2018-07-01 (annotated)

Committer:
daniel_davvid
Date:
Sun Jul 01 11:58:14 2018 +0000
Revision:
9:3a0af995dd4c
Parent:
8:d22ecbef9b90 
updated so it can work in a weather station project

Who changed what in which revision?

UserRevisionLine numberNew contents of line
MACRUM 1:763a4018aaec 1 /**
12104404 7:c72b726c7dc9 2 * BMP280 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 *
charly 8:d22ecbef9b90 8 * bugfixing by charly
charly 8:d22ecbef9b90 9 *
12104404 7:c72b726c7dc9 10 * Library for "BMP280 temperature, humidity and pressure sensor module" from Switch Science
MACRUM 1:763a4018aaec 11 * https://www.switch-science.com/catalog/2236/
MACRUM 1:763a4018aaec 12 *
12104404 7:c72b726c7dc9 13 * For more information about the BMP280:
12104404 7:c72b726c7dc9 14 * http://ae-bst.resource.bosch.com/media/products/dokumente/BMP280/BST-BMP280_DS001-10.pdf
MACRUM 1:763a4018aaec 15 */
MACRUM 1:763a4018aaec 16
MACRUM 0:ade9be832910 17 #include "mbed.h"
12104404 5:7139d5accbc3 18 #include "BMP280.h"
MACRUM 0:ade9be832910 19
12104404 7:c72b726c7dc9 20 BMP280::BMP280(PinName sda, PinName scl, char slave_adr)
MACRUM 0:ade9be832910 21 :
MACRUM 0:ade9be832910 22 i2c_p(new I2C(sda, scl)),
MACRUM 0:ade9be832910 23 i2c(*i2c_p),
charly 8:d22ecbef9b90 24 address(slave_adr<<1),
MACRUM 0:ade9be832910 25 t_fine(0)
MACRUM 0:ade9be832910 26 {
MACRUM 0:ade9be832910 27 initialize();
MACRUM 0:ade9be832910 28 }
MACRUM 0:ade9be832910 29
12104404 7:c72b726c7dc9 30 BMP280::BMP280(I2C &i2c_obj, char slave_adr)
MACRUM 0:ade9be832910 31 :
MACRUM 0:ade9be832910 32 i2c_p(NULL),
MACRUM 0:ade9be832910 33 i2c(i2c_obj),
charly 8:d22ecbef9b90 34 address(slave_adr<<1),
MACRUM 0:ade9be832910 35 t_fine(0)
MACRUM 0:ade9be832910 36 {
MACRUM 0:ade9be832910 37 initialize();
MACRUM 0:ade9be832910 38 }
MACRUM 0:ade9be832910 39
12104404 7:c72b726c7dc9 40 BMP280::~BMP280()
MACRUM 0:ade9be832910 41 {
MACRUM 0:ade9be832910 42 if (NULL != i2c_p)
MACRUM 0:ade9be832910 43 delete i2c_p;
MACRUM 0:ade9be832910 44 }
MACRUM 0:ade9be832910 45
12104404 7:c72b726c7dc9 46 void BMP280::initialize()
MACRUM 0:ade9be832910 47 {
MACRUM 0:ade9be832910 48 char cmd[18];
MACRUM 0:ade9be832910 49
charly 8:d22ecbef9b90 50 //cmd[0] = 0xf2; // ctrl_hum
charly 8:d22ecbef9b90 51 //cmd[1] = 0x01; // Humidity oversampling x1
charly 8:d22ecbef9b90 52 //i2c.write(address, cmd, 2);
MACRUM 0:ade9be832910 53
MACRUM 0:ade9be832910 54 cmd[0] = 0xf4; // ctrl_meas
charly 8:d22ecbef9b90 55 //cmd[1] = 0x27; // Temparature oversampling x1, Pressure oversampling x1, Normal mode
charly 8:d22ecbef9b90 56 cmd[1] = 0b01010111; // Temparature oversampling x2 010, Pressure oversampling x16 101, Normal mode 11
MACRUM 0:ade9be832910 57 i2c.write(address, cmd, 2);
MACRUM 0:ade9be832910 58
MACRUM 0:ade9be832910 59 cmd[0] = 0xf5; // config
charly 8:d22ecbef9b90 60 cmd[1] = 0b10111100; // Standby 1000ms, Filter x16
MACRUM 0:ade9be832910 61 i2c.write(address, cmd, 2);
MACRUM 0:ade9be832910 62
MACRUM 0:ade9be832910 63 cmd[0] = 0x88; // read dig_T regs
MACRUM 0:ade9be832910 64 i2c.write(address, cmd, 1);
MACRUM 0:ade9be832910 65 i2c.read(address, cmd, 6);
MACRUM 0:ade9be832910 66
MACRUM 0:ade9be832910 67 dig_T1 = (cmd[1] << 8) | cmd[0];
MACRUM 0:ade9be832910 68 dig_T2 = (cmd[3] << 8) | cmd[2];
MACRUM 0:ade9be832910 69 dig_T3 = (cmd[5] << 8) | cmd[4];
MACRUM 0:ade9be832910 70
charly 8:d22ecbef9b90 71 DEBUG_PRINT("dig_T = 0x%x, 0x%x, 0x%x\n\r", dig_T1, dig_T2, dig_T3);
charly 8:d22ecbef9b90 72 DEBUG_PRINT("dig_T = %d, %d, %d\n\r", 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
12104404 6:d03826fe1062 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);
12104404 6:d03826fe1062 105 */
MACRUM 0:ade9be832910 106 }
MACRUM 0:ade9be832910 107
12104404 7:c72b726c7dc9 108 float BMP280::getTemperature()
MACRUM 0:ade9be832910 109 {
charly 8:d22ecbef9b90 110 int32_t temp_raw;
MACRUM 0:ade9be832910 111 float tempf;
MACRUM 0:ade9be832910 112 char cmd[4];
MACRUM 0:ade9be832910 113
MACRUM 0:ade9be832910 114 cmd[0] = 0xfa; // temp_msb
MACRUM 0:ade9be832910 115 i2c.write(address, cmd, 1);
takafuminaka 3:d4eb81284ea0 116 i2c.read(address, &cmd[1], 3);
MACRUM 0:ade9be832910 117
MACRUM 0:ade9be832910 118 temp_raw = (cmd[1] << 12) | (cmd[2] << 4) | (cmd[3] >> 4);
charly 8:d22ecbef9b90 119 DEBUG_PRINT("\r\ntemp_raw:%d",temp_raw);
MACRUM 0:ade9be832910 120
charly 8:d22ecbef9b90 121 int32_t temp1, temp2,temp;
MACRUM 0:ade9be832910 122
charly 8:d22ecbef9b90 123 temp1 =((((temp_raw >> 3) - (dig_T1 << 1))) * dig_T2) >> 11;
charly 8:d22ecbef9b90 124 temp2 =(((((temp_raw >> 4) - dig_T1) * ((temp_raw >> 4) - dig_T1)) >> 12) * dig_T3) >> 14;
charly 8:d22ecbef9b90 125 DEBUG_PRINT(" temp1:%d temp2:%d",temp1, temp2);
charly 8:d22ecbef9b90 126 t_fine = temp1+temp2;
charly 8:d22ecbef9b90 127 DEBUG_PRINT(" t_fine:%d",t_fine);
charly 8:d22ecbef9b90 128 temp = (t_fine * 5 + 128) >> 8;
MACRUM 0:ade9be832910 129 tempf = (float)temp;
charly 8:d22ecbef9b90 130 DEBUG_PRINT(" tempf:%f",tempf);
charly 8:d22ecbef9b90 131
MACRUM 0:ade9be832910 132 return (tempf/100.0f);
MACRUM 0:ade9be832910 133 }
MACRUM 0:ade9be832910 134
12104404 7:c72b726c7dc9 135 float BMP280::getPressure()
MACRUM 0:ade9be832910 136 {
MACRUM 0:ade9be832910 137 uint32_t press_raw;
MACRUM 0:ade9be832910 138 float pressf;
MACRUM 0:ade9be832910 139 char cmd[4];
MACRUM 0:ade9be832910 140
MACRUM 0:ade9be832910 141 cmd[0] = 0xf7; // press_msb
MACRUM 0:ade9be832910 142 i2c.write(address, cmd, 1);
takafuminaka 3:d4eb81284ea0 143 i2c.read(address, &cmd[1], 3);
MACRUM 0:ade9be832910 144
MACRUM 0:ade9be832910 145 press_raw = (cmd[1] << 12) | (cmd[2] << 4) | (cmd[3] >> 4);
MACRUM 0:ade9be832910 146
MACRUM 0:ade9be832910 147 int32_t var1, var2;
MACRUM 0:ade9be832910 148 uint32_t press;
MACRUM 0:ade9be832910 149
MACRUM 0:ade9be832910 150 var1 = (t_fine >> 1) - 64000;
MACRUM 0:ade9be832910 151 var2 = (((var1 >> 2) * (var1 >> 2)) >> 11) * dig_P6;
MACRUM 0:ade9be832910 152 var2 = var2 + ((var1 * dig_P5) << 1);
MACRUM 0:ade9be832910 153 var2 = (var2 >> 2) + (dig_P4 << 16);
MACRUM 0:ade9be832910 154 var1 = (((dig_P3 * (((var1 >> 2)*(var1 >> 2)) >> 13)) >> 3) + ((dig_P2 * var1) >> 1)) >> 18;
MACRUM 0:ade9be832910 155 var1 = ((32768 + var1) * dig_P1) >> 15;
MACRUM 0:ade9be832910 156 if (var1 == 0) {
MACRUM 0:ade9be832910 157 return 0;
MACRUM 0:ade9be832910 158 }
MACRUM 0:ade9be832910 159 press = (((1048576 - press_raw) - (var2 >> 12))) * 3125;
MACRUM 0:ade9be832910 160 if(press < 0x80000000) {
MACRUM 0:ade9be832910 161 press = (press << 1) / var1;
MACRUM 0:ade9be832910 162 } else {
MACRUM 0:ade9be832910 163 press = (press / var1) * 2;
MACRUM 0:ade9be832910 164 }
MACRUM 0:ade9be832910 165 var1 = ((int32_t)dig_P9 * ((int32_t)(((press >> 3) * (press >> 3)) >> 13))) >> 12;
MACRUM 0:ade9be832910 166 var2 = (((int32_t)(press >> 2)) * (int32_t)dig_P8) >> 13;
MACRUM 0:ade9be832910 167 press = (press + ((var1 + var2 + dig_P7) >> 4));
MACRUM 0:ade9be832910 168
MACRUM 0:ade9be832910 169 pressf = (float)press;
MACRUM 0:ade9be832910 170 return (pressf/100.0f);
12104404 7:c72b726c7dc9 171 }