Mehdi Hamm / Mbed 2 deprecated nRF51822_SimpleControls

syscom project

Dependencies:   BLE_API mbed nRF51822

Fork of nRF51822_SimpleControls by RedBearLab

BMP085.cpp@4:608e9604ca26, 2017-01-08 (annotated)

Committer:
mehdiham
Date:
Sun Jan 08 22:06:54 2017 +0000
Revision:
4:608e9604ca26
1

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mehdiham 4:608e9604ca26 1 /*
mehdiham 4:608e9604ca26 2 * mbed library to use a Bosch Sensortec BMP085/BMP180 sensor
mehdiham 4:608e9604ca26 3 * Copyright (c) 2010 Hiroshi Suga
mehdiham 4:608e9604ca26 4 * Released under the MIT License: http://mbed.org/license/mit
mehdiham 4:608e9604ca26 5 */
mehdiham 4:608e9604ca26 6
mehdiham 4:608e9604ca26 7 /** @file BMP085.cpp
mehdiham 4:608e9604ca26 8 * @brief mbed library to use a Bosch Sensortec BMP085/BMP180 sensor
mehdiham 4:608e9604ca26 9 * barometric pressure sensor BMP085/BMP180 (Bosch Sensortec)
mehdiham 4:608e9604ca26 10 * interface: I2C digital
mehdiham 4:608e9604ca26 11 */
mehdiham 4:608e9604ca26 12
mehdiham 4:608e9604ca26 13 #include "mbed.h"
mehdiham 4:608e9604ca26 14 #include "BMP085.h"
mehdiham 4:608e9604ca26 15
mehdiham 4:608e9604ca26 16 #define WEATHER_BMP085 0xee
mehdiham 4:608e9604ca26 17 #define xpow(x, y) ((long)1 << y)
mehdiham 4:608e9604ca26 18
mehdiham 4:608e9604ca26 19 /**
mehdiham 4:608e9604ca26 20 * @brief Initializes interface (private I2C)
mehdiham 4:608e9604ca26 21 * @param p_sda port of I2C SDA
mehdiham 4:608e9604ca26 22 * @param p_scl port of I2C SCL
mehdiham 4:608e9604ca26 23 * @param p_oss parameter of OSS
mehdiham 4:608e9604ca26 24 */
mehdiham 4:608e9604ca26 25 BMP085::BMP085 (PinName p_sda, PinName p_scl, BMP085_oss p_oss) : i2c(p_sda, p_scl) {
mehdiham 4:608e9604ca26 26 init(p_oss);
mehdiham 4:608e9604ca26 27 }
mehdiham 4:608e9604ca26 28
mehdiham 4:608e9604ca26 29 /**
mehdiham 4:608e9604ca26 30 * @brief Initializes interface (public I2C)
mehdiham 4:608e9604ca26 31 * @param p_i2c instance of I2C class
mehdiham 4:608e9604ca26 32 * @param p_oss parameter of OSS
mehdiham 4:608e9604ca26 33 */
mehdiham 4:608e9604ca26 34 BMP085::BMP085 (I2C& p_i2c, BMP085_oss p_oss) : i2c(p_i2c) {
mehdiham 4:608e9604ca26 35 init(p_oss);
mehdiham 4:608e9604ca26 36 }
mehdiham 4:608e9604ca26 37
mehdiham 4:608e9604ca26 38 /**
mehdiham 4:608e9604ca26 39 * @brief Get temperature
mehdiham 4:608e9604ca26 40 * @return temperature (`C)
mehdiham 4:608e9604ca26 41 */
mehdiham 4:608e9604ca26 42 float BMP085::get_temperature() {
mehdiham 4:608e9604ca26 43 return temperature;
mehdiham 4:608e9604ca26 44 }
mehdiham 4:608e9604ca26 45
mehdiham 4:608e9604ca26 46 /**
mehdiham 4:608e9604ca26 47 * @brief Get pressure
mehdiham 4:608e9604ca26 48 * @return pressure (hPa)
mehdiham 4:608e9604ca26 49 */
mehdiham 4:608e9604ca26 50 float BMP085::get_pressure() {
mehdiham 4:608e9604ca26 51 return pressure;
mehdiham 4:608e9604ca26 52 }
mehdiham 4:608e9604ca26 53
mehdiham 4:608e9604ca26 54 /**
mehdiham 4:608e9604ca26 55 * @brief Update results
mehdiham 4:608e9604ca26 56 */
mehdiham 4:608e9604ca26 57 void BMP085::update () {
mehdiham 4:608e9604ca26 58 long t, p, ut, up, x1, x2, x3, b3, b5, b6;
mehdiham 4:608e9604ca26 59 unsigned long b4, b7;
mehdiham 4:608e9604ca26 60
mehdiham 4:608e9604ca26 61 twi_writechar(WEATHER_BMP085, 0xf4, 0x2e);
mehdiham 4:608e9604ca26 62 wait(0.01);
mehdiham 4:608e9604ca26 63 ut = twi_readshort(WEATHER_BMP085, 0xf6);
mehdiham 4:608e9604ca26 64
mehdiham 4:608e9604ca26 65 twi_writechar(WEATHER_BMP085, 0xf4, 0x34 | (oss << 6));
mehdiham 4:608e9604ca26 66 wait(0.05);
mehdiham 4:608e9604ca26 67 up = twi_readlong(WEATHER_BMP085, 0xf6) >> (8 - oss);
mehdiham 4:608e9604ca26 68
mehdiham 4:608e9604ca26 69 x1 = (ut - ac6) * ac5 / xpow(2, 15);
mehdiham 4:608e9604ca26 70 x2 = (long)mc * xpow(2, 11) / (x1 + md);
mehdiham 4:608e9604ca26 71 b5 = x1 + x2;
mehdiham 4:608e9604ca26 72 t = (b5 + 8) / xpow(2, 4);
mehdiham 4:608e9604ca26 73 temperature = (float)t / 10.0;
mehdiham 4:608e9604ca26 74
mehdiham 4:608e9604ca26 75 b6 = b5 - 4000;
mehdiham 4:608e9604ca26 76 x1 = (b2 * (b6 * b6 / xpow(2, 12))) / xpow(2, 11);
mehdiham 4:608e9604ca26 77 x2 = ac2 * b6 / xpow(2, 11);
mehdiham 4:608e9604ca26 78 x3 = x1 + x2;
mehdiham 4:608e9604ca26 79 b3 = ((((unsigned long)ac1 * 4 + x3) << oss) + 2) / 4;
mehdiham 4:608e9604ca26 80 x1 = ac3 * b6 / xpow(2, 13);
mehdiham 4:608e9604ca26 81 x2 = (b1 * (b6 * b6 / xpow(2, 12))) / xpow(2, 16);
mehdiham 4:608e9604ca26 82 x3 = ((x1 + x2) + 2) / xpow(2, 2);
mehdiham 4:608e9604ca26 83 b4 = ac4 * (unsigned long)(x3 + 32768) / xpow(2, 15);
mehdiham 4:608e9604ca26 84 b7 = ((unsigned long)up - b3) * (50000 >> oss);
mehdiham 4:608e9604ca26 85 if (b7 < (unsigned long)0x80000000) {
mehdiham 4:608e9604ca26 86 p = (b7 * 2) / b4;
mehdiham 4:608e9604ca26 87 } else {
mehdiham 4:608e9604ca26 88 p = (b7 / b4) * 2;
mehdiham 4:608e9604ca26 89 }
mehdiham 4:608e9604ca26 90 x1 = (p / xpow(2, 8)) * (p / xpow(2, 8));
mehdiham 4:608e9604ca26 91 x1 = (x1 * 3038) / xpow(2, 16);
mehdiham 4:608e9604ca26 92 x2 = (-7357 * p) / xpow(2, 16);
mehdiham 4:608e9604ca26 93 p = p + (x1 + x2 + 3791) / xpow(2, 4);
mehdiham 4:608e9604ca26 94 pressure = (float)p / 100.0;
mehdiham 4:608e9604ca26 95 }
mehdiham 4:608e9604ca26 96
mehdiham 4:608e9604ca26 97 void BMP085::init (BMP085_oss p_oss) {
mehdiham 4:608e9604ca26 98 ac1 = twi_readshort(WEATHER_BMP085, 0xaa);
mehdiham 4:608e9604ca26 99 ac2 = twi_readshort(WEATHER_BMP085, 0xac);
mehdiham 4:608e9604ca26 100 ac3 = twi_readshort(WEATHER_BMP085, 0xae);
mehdiham 4:608e9604ca26 101 ac4 = twi_readshort(WEATHER_BMP085, 0xb0);
mehdiham 4:608e9604ca26 102 ac5 = twi_readshort(WEATHER_BMP085, 0xb2);
mehdiham 4:608e9604ca26 103 ac6 = twi_readshort(WEATHER_BMP085, 0xb4);
mehdiham 4:608e9604ca26 104 b1 = twi_readshort(WEATHER_BMP085, 0xb6);
mehdiham 4:608e9604ca26 105 b2 = twi_readshort(WEATHER_BMP085, 0xb8);
mehdiham 4:608e9604ca26 106 mb = twi_readshort(WEATHER_BMP085, 0xba);
mehdiham 4:608e9604ca26 107 mc = twi_readshort(WEATHER_BMP085, 0xbc);
mehdiham 4:608e9604ca26 108 md = twi_readshort(WEATHER_BMP085, 0xbe);
mehdiham 4:608e9604ca26 109 oss = p_oss;
mehdiham 4:608e9604ca26 110 }
mehdiham 4:608e9604ca26 111
mehdiham 4:608e9604ca26 112 unsigned short BMP085::twi_readshort (int id, int addr) {
mehdiham 4:608e9604ca26 113 unsigned short i;
mehdiham 4:608e9604ca26 114
mehdiham 4:608e9604ca26 115 i2c.start();
mehdiham 4:608e9604ca26 116 i2c.write(id);
mehdiham 4:608e9604ca26 117 i2c.write(addr);
mehdiham 4:608e9604ca26 118
mehdiham 4:608e9604ca26 119 i2c.start();
mehdiham 4:608e9604ca26 120 i2c.write(id | 1);
mehdiham 4:608e9604ca26 121 i = i2c.read(1) << 8;
mehdiham 4:608e9604ca26 122 i |= i2c.read(0);
mehdiham 4:608e9604ca26 123 i2c.stop();
mehdiham 4:608e9604ca26 124
mehdiham 4:608e9604ca26 125 return i;
mehdiham 4:608e9604ca26 126 }
mehdiham 4:608e9604ca26 127
mehdiham 4:608e9604ca26 128 unsigned long BMP085::twi_readlong (int id, int addr) {
mehdiham 4:608e9604ca26 129 unsigned long i;
mehdiham 4:608e9604ca26 130
mehdiham 4:608e9604ca26 131 i2c.start();
mehdiham 4:608e9604ca26 132 i2c.write(id);
mehdiham 4:608e9604ca26 133 i2c.write(addr);
mehdiham 4:608e9604ca26 134
mehdiham 4:608e9604ca26 135 i2c.start();
mehdiham 4:608e9604ca26 136 i2c.write(id | 1);
mehdiham 4:608e9604ca26 137 i = i2c.read(1) << 16;
mehdiham 4:608e9604ca26 138 i |= i2c.read(1) << 8;
mehdiham 4:608e9604ca26 139 i |= i2c.read(0);
mehdiham 4:608e9604ca26 140 i2c.stop();
mehdiham 4:608e9604ca26 141
mehdiham 4:608e9604ca26 142 return i;
mehdiham 4:608e9604ca26 143 }
mehdiham 4:608e9604ca26 144
mehdiham 4:608e9604ca26 145 void BMP085::twi_writechar (int id, int addr, int dat) {
mehdiham 4:608e9604ca26 146
mehdiham 4:608e9604ca26 147 i2c.start();
mehdiham 4:608e9604ca26 148 i2c.write(id);
mehdiham 4:608e9604ca26 149 i2c.write(addr);
mehdiham 4:608e9604ca26 150 i2c.write(dat);
mehdiham 4:608e9604ca26 151 i2c.stop();
mehdiham 4:608e9604ca26 152 }