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BMP280/BMP280.cpp@11:ce2a977dcab0, 2018-01-09 (annotated)

Committer:
liam_grazier
Date:
Tue Jan 09 11:59:10 2018 +0000
Revision:
11:ce2a977dcab0
NEW NON LIB;

Who changed what in which revision?

UserRevisionLine numberNew contents of line
liam_grazier 11:ce2a977dcab0 1 /**
liam_grazier 11:ce2a977dcab0 2 * BMP280 Combined humidity and pressure sensor library
liam_grazier 11:ce2a977dcab0 3 *
liam_grazier 11:ce2a977dcab0 4 * @author Toyomasa Watarai
liam_grazier 11:ce2a977dcab0 5 * @version 1.0
liam_grazier 11:ce2a977dcab0 6 * @date 06-April-2015
liam_grazier 11:ce2a977dcab0 7 *
liam_grazier 11:ce2a977dcab0 8 * bugfixing by charly
liam_grazier 11:ce2a977dcab0 9 *
liam_grazier 11:ce2a977dcab0 10 * Library for "BMP280 temperature, humidity and pressure sensor module" from Switch Science
liam_grazier 11:ce2a977dcab0 11 * https://www.switch-science.com/catalog/2236/
liam_grazier 11:ce2a977dcab0 12 *
liam_grazier 11:ce2a977dcab0 13 * For more information about the BMP280:
liam_grazier 11:ce2a977dcab0 14 * http://ae-bst.resource.bosch.com/media/products/dokumente/BMP280/BST-BMP280_DS001-10.pdf
liam_grazier 11:ce2a977dcab0 15 */
liam_grazier 11:ce2a977dcab0 16
liam_grazier 11:ce2a977dcab0 17 #include "mbed.h"
liam_grazier 11:ce2a977dcab0 18 #include "BMP280.h"
liam_grazier 11:ce2a977dcab0 19
liam_grazier 11:ce2a977dcab0 20 BMP280::BMP280(PinName sda, PinName scl, char slave_adr)
liam_grazier 11:ce2a977dcab0 21 :
liam_grazier 11:ce2a977dcab0 22 i2c_p(new I2C(sda, scl)),
liam_grazier 11:ce2a977dcab0 23 i2c(*i2c_p),
liam_grazier 11:ce2a977dcab0 24 address(slave_adr<<1),
liam_grazier 11:ce2a977dcab0 25 t_fine(0)
liam_grazier 11:ce2a977dcab0 26 {
liam_grazier 11:ce2a977dcab0 27 initialize();
liam_grazier 11:ce2a977dcab0 28 }
liam_grazier 11:ce2a977dcab0 29
liam_grazier 11:ce2a977dcab0 30 BMP280::BMP280(I2C &i2c_obj, char slave_adr)
liam_grazier 11:ce2a977dcab0 31 :
liam_grazier 11:ce2a977dcab0 32 i2c_p(NULL),
liam_grazier 11:ce2a977dcab0 33 i2c(i2c_obj),
liam_grazier 11:ce2a977dcab0 34 address(slave_adr<<1),
liam_grazier 11:ce2a977dcab0 35 t_fine(0)
liam_grazier 11:ce2a977dcab0 36 {
liam_grazier 11:ce2a977dcab0 37 initialize();
liam_grazier 11:ce2a977dcab0 38 }
liam_grazier 11:ce2a977dcab0 39
liam_grazier 11:ce2a977dcab0 40 BMP280::~BMP280()
liam_grazier 11:ce2a977dcab0 41 {
liam_grazier 11:ce2a977dcab0 42 if (NULL != i2c_p)
liam_grazier 11:ce2a977dcab0 43 delete i2c_p;
liam_grazier 11:ce2a977dcab0 44 }
liam_grazier 11:ce2a977dcab0 45
liam_grazier 11:ce2a977dcab0 46 void BMP280::initialize()
liam_grazier 11:ce2a977dcab0 47 {
liam_grazier 11:ce2a977dcab0 48 char cmd[18];
liam_grazier 11:ce2a977dcab0 49
liam_grazier 11:ce2a977dcab0 50 //cmd[0] = 0xf2; // ctrl_hum
liam_grazier 11:ce2a977dcab0 51 //cmd[1] = 0x01; // Humidity oversampling x1
liam_grazier 11:ce2a977dcab0 52 //i2c.write(address, cmd, 2);
liam_grazier 11:ce2a977dcab0 53
liam_grazier 11:ce2a977dcab0 54 cmd[0] = 0xf4; // ctrl_meas
liam_grazier 11:ce2a977dcab0 55 //cmd[1] = 0x27; // Temparature oversampling x1, Pressure oversampling x1, Normal mode
liam_grazier 11:ce2a977dcab0 56 cmd[1] = 0b01010111; // Temparature oversampling x2 010, Pressure oversampling x16 101, Normal mode 11
liam_grazier 11:ce2a977dcab0 57 i2c.write(address, cmd, 2);
liam_grazier 11:ce2a977dcab0 58
liam_grazier 11:ce2a977dcab0 59 cmd[0] = 0xf5; // config
liam_grazier 11:ce2a977dcab0 60 cmd[1] = 0b10111100; // Standby 1000ms, Filter x16
liam_grazier 11:ce2a977dcab0 61 i2c.write(address, cmd, 2);
liam_grazier 11:ce2a977dcab0 62
liam_grazier 11:ce2a977dcab0 63 cmd[0] = 0x88; // read dig_T regs
liam_grazier 11:ce2a977dcab0 64 i2c.write(address, cmd, 1);
liam_grazier 11:ce2a977dcab0 65 i2c.read(address, cmd, 6);
liam_grazier 11:ce2a977dcab0 66
liam_grazier 11:ce2a977dcab0 67 dig_T1 = (cmd[1] << 8) | cmd[0];
liam_grazier 11:ce2a977dcab0 68 dig_T2 = (cmd[3] << 8) | cmd[2];
liam_grazier 11:ce2a977dcab0 69 dig_T3 = (cmd[5] << 8) | cmd[4];
liam_grazier 11:ce2a977dcab0 70
liam_grazier 11:ce2a977dcab0 71 DEBUG_PRINT("dig_T = 0x%x, 0x%x, 0x%x\n\r", dig_T1, dig_T2, dig_T3);
liam_grazier 11:ce2a977dcab0 72 DEBUG_PRINT("dig_T = %d, %d, %d\n\r", dig_T1, dig_T2, dig_T3);
liam_grazier 11:ce2a977dcab0 73
liam_grazier 11:ce2a977dcab0 74 cmd[0] = 0x8E; // read dig_P regs
liam_grazier 11:ce2a977dcab0 75 i2c.write(address, cmd, 1);
liam_grazier 11:ce2a977dcab0 76 i2c.read(address, cmd, 18);
liam_grazier 11:ce2a977dcab0 77
liam_grazier 11:ce2a977dcab0 78 dig_P1 = (cmd[ 1] << 8) | cmd[ 0];
liam_grazier 11:ce2a977dcab0 79 dig_P2 = (cmd[ 3] << 8) | cmd[ 2];
liam_grazier 11:ce2a977dcab0 80 dig_P3 = (cmd[ 5] << 8) | cmd[ 4];
liam_grazier 11:ce2a977dcab0 81 dig_P4 = (cmd[ 7] << 8) | cmd[ 6];
liam_grazier 11:ce2a977dcab0 82 dig_P5 = (cmd[ 9] << 8) | cmd[ 8];
liam_grazier 11:ce2a977dcab0 83 dig_P6 = (cmd[11] << 8) | cmd[10];
liam_grazier 11:ce2a977dcab0 84 dig_P7 = (cmd[13] << 8) | cmd[12];
liam_grazier 11:ce2a977dcab0 85 dig_P8 = (cmd[15] << 8) | cmd[14];
liam_grazier 11:ce2a977dcab0 86 dig_P9 = (cmd[17] << 8) | cmd[16];
liam_grazier 11:ce2a977dcab0 87
liam_grazier 11:ce2a977dcab0 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);
liam_grazier 11:ce2a977dcab0 89
liam_grazier 11:ce2a977dcab0 90 /* cmd[0] = 0xA1; // read dig_H regs
liam_grazier 11:ce2a977dcab0 91 i2c.write(address, cmd, 1);
liam_grazier 11:ce2a977dcab0 92 i2c.read(address, cmd, 1);
liam_grazier 11:ce2a977dcab0 93 cmd[1] = 0xE1; // read dig_H regs
liam_grazier 11:ce2a977dcab0 94 i2c.write(address, &cmd[1], 1);
liam_grazier 11:ce2a977dcab0 95 i2c.read(address, &cmd[1], 7);
liam_grazier 11:ce2a977dcab0 96
liam_grazier 11:ce2a977dcab0 97 dig_H1 = cmd[0];
liam_grazier 11:ce2a977dcab0 98 dig_H2 = (cmd[2] << 8) | cmd[1];
liam_grazier 11:ce2a977dcab0 99 dig_H3 = cmd[3];
liam_grazier 11:ce2a977dcab0 100 dig_H4 = (cmd[4] << 4) | (cmd[5] & 0x0f);
liam_grazier 11:ce2a977dcab0 101 dig_H5 = (cmd[6] << 4) | ((cmd[5]>>4) & 0x0f);
liam_grazier 11:ce2a977dcab0 102 dig_H6 = cmd[7];
liam_grazier 11:ce2a977dcab0 103
liam_grazier 11:ce2a977dcab0 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);
liam_grazier 11:ce2a977dcab0 105 */
liam_grazier 11:ce2a977dcab0 106 }
liam_grazier 11:ce2a977dcab0 107
liam_grazier 11:ce2a977dcab0 108 float BMP280::getTemperature()
liam_grazier 11:ce2a977dcab0 109 {
liam_grazier 11:ce2a977dcab0 110 int32_t temp_raw;
liam_grazier 11:ce2a977dcab0 111 float tempf;
liam_grazier 11:ce2a977dcab0 112 char cmd[4];
liam_grazier 11:ce2a977dcab0 113
liam_grazier 11:ce2a977dcab0 114 cmd[0] = 0xfa; // temp_msb
liam_grazier 11:ce2a977dcab0 115 i2c.write(address, cmd, 1);
liam_grazier 11:ce2a977dcab0 116 i2c.read(address, &cmd[1], 3);
liam_grazier 11:ce2a977dcab0 117
liam_grazier 11:ce2a977dcab0 118 temp_raw = (cmd[1] << 12) | (cmd[2] << 4) | (cmd[3] >> 4);
liam_grazier 11:ce2a977dcab0 119 DEBUG_PRINT("\r\ntemp_raw:%d",temp_raw);
liam_grazier 11:ce2a977dcab0 120
liam_grazier 11:ce2a977dcab0 121 int32_t temp1, temp2,temp;
liam_grazier 11:ce2a977dcab0 122
liam_grazier 11:ce2a977dcab0 123 temp1 =((((temp_raw >> 3) - (dig_T1 << 1))) * dig_T2) >> 11;
liam_grazier 11:ce2a977dcab0 124 temp2 =(((((temp_raw >> 4) - dig_T1) * ((temp_raw >> 4) - dig_T1)) >> 12) * dig_T3) >> 14;
liam_grazier 11:ce2a977dcab0 125 DEBUG_PRINT(" temp1:%d temp2:%d",temp1, temp2);
liam_grazier 11:ce2a977dcab0 126 t_fine = temp1+temp2;
liam_grazier 11:ce2a977dcab0 127 DEBUG_PRINT(" t_fine:%d",t_fine);
liam_grazier 11:ce2a977dcab0 128 temp = (t_fine * 5 + 128) >> 8;
liam_grazier 11:ce2a977dcab0 129 tempf = (float)temp;
liam_grazier 11:ce2a977dcab0 130 DEBUG_PRINT(" tempf:%f",tempf);
liam_grazier 11:ce2a977dcab0 131
liam_grazier 11:ce2a977dcab0 132 return (tempf/100.0f);
liam_grazier 11:ce2a977dcab0 133 }
liam_grazier 11:ce2a977dcab0 134
liam_grazier 11:ce2a977dcab0 135 float BMP280::getPressure()
liam_grazier 11:ce2a977dcab0 136 {
liam_grazier 11:ce2a977dcab0 137 uint32_t press_raw;
liam_grazier 11:ce2a977dcab0 138 float pressf;
liam_grazier 11:ce2a977dcab0 139 char cmd[4];
liam_grazier 11:ce2a977dcab0 140
liam_grazier 11:ce2a977dcab0 141 cmd[0] = 0xf7; // press_msb
liam_grazier 11:ce2a977dcab0 142 i2c.write(address, cmd, 1);
liam_grazier 11:ce2a977dcab0 143 i2c.read(address, &cmd[1], 3);
liam_grazier 11:ce2a977dcab0 144
liam_grazier 11:ce2a977dcab0 145 press_raw = (cmd[1] << 12) | (cmd[2] << 4) | (cmd[3] >> 4);
liam_grazier 11:ce2a977dcab0 146
liam_grazier 11:ce2a977dcab0 147 int32_t var1, var2;
liam_grazier 11:ce2a977dcab0 148 uint32_t press;
liam_grazier 11:ce2a977dcab0 149
liam_grazier 11:ce2a977dcab0 150 var1 = (t_fine >> 1) - 64000;
liam_grazier 11:ce2a977dcab0 151 var2 = (((var1 >> 2) * (var1 >> 2)) >> 11) * dig_P6;
liam_grazier 11:ce2a977dcab0 152 var2 = var2 + ((var1 * dig_P5) << 1);
liam_grazier 11:ce2a977dcab0 153 var2 = (var2 >> 2) + (dig_P4 << 16);
liam_grazier 11:ce2a977dcab0 154 var1 = (((dig_P3 * (((var1 >> 2)*(var1 >> 2)) >> 13)) >> 3) + ((dig_P2 * var1) >> 1)) >> 18;
liam_grazier 11:ce2a977dcab0 155 var1 = ((32768 + var1) * dig_P1) >> 15;
liam_grazier 11:ce2a977dcab0 156 if (var1 == 0) {
liam_grazier 11:ce2a977dcab0 157 return 0;
liam_grazier 11:ce2a977dcab0 158 }
liam_grazier 11:ce2a977dcab0 159 press = (((1048576 - press_raw) - (var2 >> 12))) * 3125;
liam_grazier 11:ce2a977dcab0 160 if(press < 0x80000000) {
liam_grazier 11:ce2a977dcab0 161 press = (press << 1) / var1;
liam_grazier 11:ce2a977dcab0 162 } else {
liam_grazier 11:ce2a977dcab0 163 press = (press / var1) * 2;
liam_grazier 11:ce2a977dcab0 164 }
liam_grazier 11:ce2a977dcab0 165 var1 = ((int32_t)dig_P9 * ((int32_t)(((press >> 3) * (press >> 3)) >> 13))) >> 12;
liam_grazier 11:ce2a977dcab0 166 var2 = (((int32_t)(press >> 2)) * (int32_t)dig_P8) >> 13;
liam_grazier 11:ce2a977dcab0 167 press = (press + ((var1 + var2 + dig_P7) >> 4));
liam_grazier 11:ce2a977dcab0 168
liam_grazier 11:ce2a977dcab0 169 pressf = (float)press;
liam_grazier 11:ce2a977dcab0 170 return (pressf/100.0f);
liam_grazier 11:ce2a977dcab0 171 }