Abdelmalek BELLOULA
interface to chr_6dm and Baro bmp085
BMP085.cpp@0:d07617f8ede9, 2011-10-17 (annotated)
- Committer:
- belloula
- Date:
- Mon Oct 17 19:43:06 2011 +0000
- Revision:
- 0:d07617f8ede9
Who changed what in which revision?
| User | Revision | Line number | New contents of line |
|---|---|---|---|
| belloula | 0:d07617f8ede9 | 1 | /* |
| belloula | 0:d07617f8ede9 | 2 | * mbed library to use a Bosch Sensortec BMP085 sensor |
| belloula | 0:d07617f8ede9 | 3 | * Copyright (c) 2010 Hiroshi Suga |
| belloula | 0:d07617f8ede9 | 4 | * Released under the MIT License: http://mbed.org/license/mit |
| belloula | 0:d07617f8ede9 | 5 | */ |
| belloula | 0:d07617f8ede9 | 6 | |
| belloula | 0:d07617f8ede9 | 7 | /** @file BMP085.cpp |
| belloula | 0:d07617f8ede9 | 8 | * @brief mbed library to use a Bosch Sensortec BMP085 sensor |
| belloula | 0:d07617f8ede9 | 9 | * barometric pressure sensor BMP085 (Bosch Sensortec) |
| belloula | 0:d07617f8ede9 | 10 | * interface: I2C digital |
| belloula | 0:d07617f8ede9 | 11 | */ |
| belloula | 0:d07617f8ede9 | 12 | |
| belloula | 0:d07617f8ede9 | 13 | #include "mbed.h" |
| belloula | 0:d07617f8ede9 | 14 | #include "BMP085.h" |
| belloula | 0:d07617f8ede9 | 15 | |
| belloula | 0:d07617f8ede9 | 16 | #define WEATHER_BMP085 0xee |
| belloula | 0:d07617f8ede9 | 17 | #define xpow(x, y) ((long)1 << y) |
| belloula | 0:d07617f8ede9 | 18 | |
| belloula | 0:d07617f8ede9 | 19 | /** |
| belloula | 0:d07617f8ede9 | 20 | * @brief Initializes interface (private I2C) |
| belloula | 0:d07617f8ede9 | 21 | * @param p_sda port of I2C SDA |
| belloula | 0:d07617f8ede9 | 22 | * @param p_scl port of I2C SCL |
| belloula | 0:d07617f8ede9 | 23 | * @param p_oss parameter of OSS |
| belloula | 0:d07617f8ede9 | 24 | */ |
| belloula | 0:d07617f8ede9 | 25 | BMP085::BMP085 (PinName p_sda, PinName p_scl, BMP085_oss p_oss) : i2c(p_sda, p_scl) |
| belloula | 0:d07617f8ede9 | 26 | { |
| belloula | 0:d07617f8ede9 | 27 | init(p_oss); |
| belloula | 0:d07617f8ede9 | 28 | ok=0; |
| belloula | 0:d07617f8ede9 | 29 | } |
| belloula | 0:d07617f8ede9 | 30 | |
| belloula | 0:d07617f8ede9 | 31 | /** |
| belloula | 0:d07617f8ede9 | 32 | * @brief Initializes interface (public I2C) |
| belloula | 0:d07617f8ede9 | 33 | * @param p_i2c instance of I2C class |
| belloula | 0:d07617f8ede9 | 34 | * @param p_oss parameter of OSS |
| belloula | 0:d07617f8ede9 | 35 | */ |
| belloula | 0:d07617f8ede9 | 36 | BMP085::BMP085 (I2C& p_i2c, BMP085_oss p_oss) : i2c(p_i2c) |
| belloula | 0:d07617f8ede9 | 37 | { |
| belloula | 0:d07617f8ede9 | 38 | init(p_oss); |
| belloula | 0:d07617f8ede9 | 39 | ok=0; |
| belloula | 0:d07617f8ede9 | 40 | } |
| belloula | 0:d07617f8ede9 | 41 | |
| belloula | 0:d07617f8ede9 | 42 | /** |
| belloula | 0:d07617f8ede9 | 43 | * @brief Get temperature |
| belloula | 0:d07617f8ede9 | 44 | * @return temperature (`C) |
| belloula | 0:d07617f8ede9 | 45 | */ |
| belloula | 0:d07617f8ede9 | 46 | float BMP085::get_temperature() |
| belloula | 0:d07617f8ede9 | 47 | { |
| belloula | 0:d07617f8ede9 | 48 | return temperature; |
| belloula | 0:d07617f8ede9 | 49 | } |
| belloula | 0:d07617f8ede9 | 50 | |
| belloula | 0:d07617f8ede9 | 51 | /** |
| belloula | 0:d07617f8ede9 | 52 | * @brief Get pressure |
| belloula | 0:d07617f8ede9 | 53 | * @return pressure (hPa) |
| belloula | 0:d07617f8ede9 | 54 | */ |
| belloula | 0:d07617f8ede9 | 55 | float BMP085::get_pressure() |
| belloula | 0:d07617f8ede9 | 56 | { |
| belloula | 0:d07617f8ede9 | 57 | return pressure; |
| belloula | 0:d07617f8ede9 | 58 | } |
| belloula | 0:d07617f8ede9 | 59 | /** |
| belloula | 0:d07617f8ede9 | 60 | * @brief Get altitude e |
| belloula | 0:d07617f8ede9 | 61 | * @return altitude (m) |
| belloula | 0:d07617f8ede9 | 62 | */ |
| belloula | 0:d07617f8ede9 | 63 | float BMP085::get_altitude() |
| belloula | 0:d07617f8ede9 | 64 | { |
| belloula | 0:d07617f8ede9 | 65 | return altitude; |
| belloula | 0:d07617f8ede9 | 66 | } |
| belloula | 0:d07617f8ede9 | 67 | |
| belloula | 0:d07617f8ede9 | 68 | |
| belloula | 0:d07617f8ede9 | 69 | /** |
| belloula | 0:d07617f8ede9 | 70 | * @brief Update results |
| belloula | 0:d07617f8ede9 | 71 | */ |
| belloula | 0:d07617f8ede9 | 72 | void BMP085::update () |
| belloula | 0:d07617f8ede9 | 73 | { |
| belloula | 0:d07617f8ede9 | 74 | static long t, p, ut, up, x1, x2, x3, b3, b5, b6; |
| belloula | 0:d07617f8ede9 | 75 | static unsigned long b4, b7; |
| belloula | 0:d07617f8ede9 | 76 | static unsigned int nbtick=0; |
| belloula | 0:d07617f8ede9 | 77 | |
| belloula | 0:d07617f8ede9 | 78 | switch(nbtick){ |
| belloula | 0:d07617f8ede9 | 79 | case 0 : twi_writechar(WEATHER_BMP085, 0xf4, 0x2e); |
| belloula | 0:d07617f8ede9 | 80 | nbtick=1; |
| belloula | 0:d07617f8ede9 | 81 | break; |
| belloula | 0:d07617f8ede9 | 82 | case 1 : ut = twi_readshort(WEATHER_BMP085, 0xf6); |
| belloula | 0:d07617f8ede9 | 83 | twi_writechar(WEATHER_BMP085, 0xf4, 0x34 | (oss << 6)); |
| belloula | 0:d07617f8ede9 | 84 | nbtick=2; |
| belloula | 0:d07617f8ede9 | 85 | break; |
| belloula | 0:d07617f8ede9 | 86 | case 2 : |
| belloula | 0:d07617f8ede9 | 87 | case 3 : |
| belloula | 0:d07617f8ede9 | 88 | case 4 : |
| belloula | 0:d07617f8ede9 | 89 | case 5 : |
| belloula | 0:d07617f8ede9 | 90 | case 6 : |
| belloula | 0:d07617f8ede9 | 91 | //case 7 : |
| belloula | 0:d07617f8ede9 | 92 | nbtick++; |
| belloula | 0:d07617f8ede9 | 93 | break; |
| belloula | 0:d07617f8ede9 | 94 | case 7 : up = twi_readlong(WEATHER_BMP085, 0xf6) >> (8 - oss); |
| belloula | 0:d07617f8ede9 | 95 | x1 = (ut - ac6) * ac5 / xpow(2, 15); |
| belloula | 0:d07617f8ede9 | 96 | x2 = (long)mc * xpow(2, 11) / (x1 + md); |
| belloula | 0:d07617f8ede9 | 97 | b5 = x1 + x2; |
| belloula | 0:d07617f8ede9 | 98 | t = (b5 + 8) / xpow(2, 4); |
| belloula | 0:d07617f8ede9 | 99 | temperature = (float)t / 10.0; |
| belloula | 0:d07617f8ede9 | 100 | b6 = b5 - 4000; |
| belloula | 0:d07617f8ede9 | 101 | x1 = (b2 * (b6 * b6 / xpow(2, 12))) / xpow(2, 11); |
| belloula | 0:d07617f8ede9 | 102 | x2 = ac2 * b6 / xpow(2, 11); |
| belloula | 0:d07617f8ede9 | 103 | x3 = x1 + x2; |
| belloula | 0:d07617f8ede9 | 104 | b3 = ((((unsigned long)ac1 * 4 + x3) << oss) + 2) / 4; |
| belloula | 0:d07617f8ede9 | 105 | x1 = ac3 * b6 / xpow(2, 13); |
| belloula | 0:d07617f8ede9 | 106 | x2 = (b1 * (b6 * b6 / xpow(2, 12))) / xpow(2, 16); |
| belloula | 0:d07617f8ede9 | 107 | x3 = ((x1 + x2) + 2) / xpow(2, 2); |
| belloula | 0:d07617f8ede9 | 108 | b4 = ac4 * (unsigned long)(x3 + 32768) / xpow(2, 15); |
| belloula | 0:d07617f8ede9 | 109 | b7 = ((unsigned long)up - b3) * (50000 >> oss); |
| belloula | 0:d07617f8ede9 | 110 | if (b7 < (unsigned long)0x80000000) { |
| belloula | 0:d07617f8ede9 | 111 | p = (b7 * 2) / b4; |
| belloula | 0:d07617f8ede9 | 112 | } else { |
| belloula | 0:d07617f8ede9 | 113 | p = (b7 / b4) * 2; |
| belloula | 0:d07617f8ede9 | 114 | } |
| belloula | 0:d07617f8ede9 | 115 | x1 = (p / xpow(2, 8)) * (p / xpow(2, 8)); |
| belloula | 0:d07617f8ede9 | 116 | x1 = (x1 * 3038) / xpow(2, 16); |
| belloula | 0:d07617f8ede9 | 117 | x2 = (-7357 * p) / xpow(2, 16); |
| belloula | 0:d07617f8ede9 | 118 | p = p + (x1 + x2 + 3791) / xpow(2, 4); |
| belloula | 0:d07617f8ede9 | 119 | pressure = (float)p / 100.0; |
| belloula | 0:d07617f8ede9 | 120 | ok=1; |
| belloula | 0:d07617f8ede9 | 121 | nbtick=0; |
| belloula | 0:d07617f8ede9 | 122 | break; |
| belloula | 0:d07617f8ede9 | 123 | default: nbtick=0; |
| belloula | 0:d07617f8ede9 | 124 | break; |
| belloula | 0:d07617f8ede9 | 125 | } |
| belloula | 0:d07617f8ede9 | 126 | /*float To=231; // 298 273,15 + 25 |
| belloula | 0:d07617f8ede9 | 127 | float ho=0; |
| belloula | 0:d07617f8ede9 | 128 | float Po=102400; //101325 |
| belloula | 0:d07617f8ede9 | 129 | //ecuacion |
| belloula | 0:d07617f8ede9 | 130 | float c=(To-0.0065*ho); |
| belloula | 0:d07617f8ede9 | 131 | float e=(p/Po); |
| belloula | 0:d07617f8ede9 | 132 | float d=exp(0.19082*log(e)); |
| belloula | 0:d07617f8ede9 | 133 | float b=c*d; |
| belloula | 0:d07617f8ede9 | 134 | altitude = 153.84615*(To-b); |
| belloula | 0:d07617f8ede9 | 135 | |
| belloula | 0:d07617f8ede9 | 136 | /*altitude = (float)44330 * (1 - pow(((float) pressure/Po), 0.190295)); |
| belloula | 0:d07617f8ede9 | 137 | float A = pressure/1024.00; |
| belloula | 0:d07617f8ede9 | 138 | float B = 1/5.25588; |
| belloula | 0:d07617f8ede9 | 139 | altitude = pow(A,B); |
| belloula | 0:d07617f8ede9 | 140 | altitude = 1 - altitude; |
| belloula | 0:d07617f8ede9 | 141 | altitude = altitude /0.0000225577;*/ |
| belloula | 0:d07617f8ede9 | 142 | |
| belloula | 0:d07617f8ede9 | 143 | |
| belloula | 0:d07617f8ede9 | 144 | |
| belloula | 0:d07617f8ede9 | 145 | |
| belloula | 0:d07617f8ede9 | 146 | |
| belloula | 0:d07617f8ede9 | 147 | } |
| belloula | 0:d07617f8ede9 | 148 | |
| belloula | 0:d07617f8ede9 | 149 | void BMP085::init (BMP085_oss p_oss) { |
| belloula | 0:d07617f8ede9 | 150 | ac1 = twi_readshort(WEATHER_BMP085, 0xaa); |
| belloula | 0:d07617f8ede9 | 151 | ac2 = twi_readshort(WEATHER_BMP085, 0xac); |
| belloula | 0:d07617f8ede9 | 152 | ac3 = twi_readshort(WEATHER_BMP085, 0xae); |
| belloula | 0:d07617f8ede9 | 153 | ac4 = twi_readshort(WEATHER_BMP085, 0xb0); |
| belloula | 0:d07617f8ede9 | 154 | ac5 = twi_readshort(WEATHER_BMP085, 0xb2); |
| belloula | 0:d07617f8ede9 | 155 | ac6 = twi_readshort(WEATHER_BMP085, 0xb4); |
| belloula | 0:d07617f8ede9 | 156 | b1 = twi_readshort(WEATHER_BMP085, 0xb6); |
| belloula | 0:d07617f8ede9 | 157 | b2 = twi_readshort(WEATHER_BMP085, 0xb8); |
| belloula | 0:d07617f8ede9 | 158 | mb = twi_readshort(WEATHER_BMP085, 0xba); |
| belloula | 0:d07617f8ede9 | 159 | mc = twi_readshort(WEATHER_BMP085, 0xbc); |
| belloula | 0:d07617f8ede9 | 160 | md = twi_readshort(WEATHER_BMP085, 0xbe); |
| belloula | 0:d07617f8ede9 | 161 | oss = p_oss; |
| belloula | 0:d07617f8ede9 | 162 | } |
| belloula | 0:d07617f8ede9 | 163 | |
| belloula | 0:d07617f8ede9 | 164 | unsigned short BMP085::twi_readshort (int id, int addr) { |
| belloula | 0:d07617f8ede9 | 165 | unsigned short i; |
| belloula | 0:d07617f8ede9 | 166 | |
| belloula | 0:d07617f8ede9 | 167 | i2c.start(); |
| belloula | 0:d07617f8ede9 | 168 | i2c.write(id); |
| belloula | 0:d07617f8ede9 | 169 | i2c.write(addr); |
| belloula | 0:d07617f8ede9 | 170 | |
| belloula | 0:d07617f8ede9 | 171 | i2c.start(); |
| belloula | 0:d07617f8ede9 | 172 | i2c.write(id | 1); |
| belloula | 0:d07617f8ede9 | 173 | i = i2c.read(1) << 8; |
| belloula | 0:d07617f8ede9 | 174 | i |= i2c.read(0); |
| belloula | 0:d07617f8ede9 | 175 | i2c.stop(); |
| belloula | 0:d07617f8ede9 | 176 | |
| belloula | 0:d07617f8ede9 | 177 | return i; |
| belloula | 0:d07617f8ede9 | 178 | } |
| belloula | 0:d07617f8ede9 | 179 | |
| belloula | 0:d07617f8ede9 | 180 | unsigned long BMP085::twi_readlong (int id, int addr) { |
| belloula | 0:d07617f8ede9 | 181 | unsigned long i; |
| belloula | 0:d07617f8ede9 | 182 | |
| belloula | 0:d07617f8ede9 | 183 | i2c.start(); |
| belloula | 0:d07617f8ede9 | 184 | i2c.write(id); |
| belloula | 0:d07617f8ede9 | 185 | i2c.write(addr); |
| belloula | 0:d07617f8ede9 | 186 | |
| belloula | 0:d07617f8ede9 | 187 | i2c.start(); |
| belloula | 0:d07617f8ede9 | 188 | i2c.write(id | 1); |
| belloula | 0:d07617f8ede9 | 189 | i = i2c.read(1) << 16; |
| belloula | 0:d07617f8ede9 | 190 | i |= i2c.read(1) << 8; |
| belloula | 0:d07617f8ede9 | 191 | i |= i2c.read(0); |
| belloula | 0:d07617f8ede9 | 192 | i2c.stop(); |
| belloula | 0:d07617f8ede9 | 193 | |
| belloula | 0:d07617f8ede9 | 194 | return i; |
| belloula | 0:d07617f8ede9 | 195 | } |
| belloula | 0:d07617f8ede9 | 196 | |
| belloula | 0:d07617f8ede9 | 197 | void BMP085::twi_writechar (int id, int addr, int dat) |
| belloula | 0:d07617f8ede9 | 198 | { |
| belloula | 0:d07617f8ede9 | 199 | |
| belloula | 0:d07617f8ede9 | 200 | i2c.start(); |
| belloula | 0:d07617f8ede9 | 201 | i2c.write(id); |
| belloula | 0:d07617f8ede9 | 202 | i2c.write(addr); |
| belloula | 0:d07617f8ede9 | 203 | i2c.write(dat); |
| belloula | 0:d07617f8ede9 | 204 | i2c.stop(); |
| belloula | 0:d07617f8ede9 | 205 | } |
| belloula | 0:d07617f8ede9 | 206 |