Device driver for the BMP180 Digital pressure and temperature sensor.
Dependents: BMP180_example MAXWSNENV_sensors MAXWSNENV_sensors nRF51822_BMP180 ... more
BMP180.cpp
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Maxim Integrated Products, Inc. retains all 00030 * ownership rights. 00031 ******************************************************************************* 00032 */ 00033 00034 #include "BMP180.h" 00035 00036 /***** Definitions *****/ 00037 #define I2C_ADDR (0xEE) // 1110111x 00038 00039 #define REG_ADDR_RESET (0xE0) 00040 #define REG_ADDR_ID (0xD0) 00041 #define REG_ADDR_CTRL (0xF4) 00042 #define REG_ADDR_DATA (0xF6) 00043 #define REG_ADDR_AC1 (0xAA) 00044 00045 #define CTRL_REG_TEMP (0x2E) 00046 #define CTRL_REG_PRESS_0 (0x34) 00047 #define CTRL_REG_PRESS_1 (0x74) 00048 #define CTRL_REG_PRESS_2 (0xB4) 00049 #define CTRL_REG_PRESS_3 (0xF4) 00050 00051 //****************************************************************************** 00052 BMP180::BMP180(PinName sda, PinName scl) 00053 { 00054 i2c_ = new I2C(sda, scl); 00055 i2c_owner = true; 00056 00057 i2c_->frequency(400000); 00058 } 00059 00060 //****************************************************************************** 00061 BMP180::BMP180(I2C *i2c) : 00062 i2c_(i2c) 00063 { 00064 i2c_owner = false; 00065 } 00066 00067 //****************************************************************************** 00068 BMP180::~BMP180() 00069 { 00070 if(i2c_owner) { 00071 delete i2c_; 00072 } 00073 } 00074 00075 //****************************************************************************** 00076 int BMP180::init(void) 00077 { 00078 char addr; 00079 char data[22]; 00080 int i; 00081 00082 if (checkId() != 0) { 00083 return -1; 00084 } 00085 00086 addr = REG_ADDR_AC1; 00087 if (i2c_->write(I2C_ADDR, &addr, 1) != 0) { 00088 return -1; 00089 } 00090 00091 if (i2c_->read(I2C_ADDR, data, 22) != 0) { 00092 return -1; 00093 } 00094 00095 for (i = 0; i < 11; i++) { 00096 calib.value[i] = (data[2*i] << 8) | data[(2*i)+1]; 00097 } 00098 00099 return 0; 00100 } 00101 00102 //****************************************************************************** 00103 int BMP180::reset(void) 00104 { 00105 char data; 00106 00107 data = REG_ADDR_RESET; 00108 if (i2c_->write(I2C_ADDR, &data, 1) != 0) { 00109 return -1; 00110 } 00111 00112 data = 0xB6; 00113 if (i2c_->write(I2C_ADDR, &data, 1) != 0) { 00114 return -1; 00115 } 00116 00117 return 0; 00118 } 00119 00120 //****************************************************************************** 00121 int BMP180::checkId(void) 00122 { 00123 char addr; 00124 char data; 00125 00126 addr = REG_ADDR_ID; 00127 if (i2c_->write(I2C_ADDR, &addr, 1) != 0) { 00128 return -1; 00129 } 00130 00131 if (i2c_->read(I2C_ADDR, &data, 1) != 0) { 00132 return -1; 00133 } 00134 00135 if (data != 0x55) { 00136 return -1; 00137 } 00138 00139 return 0; 00140 } 00141 00142 //****************************************************************************** 00143 int BMP180::startPressure(BMP180::oversampling_t oss) 00144 { 00145 char data[2]; 00146 00147 data[0] = REG_ADDR_CTRL; 00148 data[1] = CTRL_REG_PRESS_0 | ((oss & 0x3) << 6); 00149 oss_ = oss; 00150 00151 if (i2c_->write(I2C_ADDR, data, 2) != 0) { 00152 return -1; 00153 } 00154 00155 return 0; 00156 } 00157 00158 //****************************************************************************** 00159 int BMP180::getPressure(int *pressure) 00160 { 00161 char addr, byte[3]; 00162 uint32_t up; 00163 int32_t b6, x1, x2, x3, b3, p; 00164 uint32_t b4, b7; 00165 00166 addr = REG_ADDR_DATA; 00167 if (i2c_->write(I2C_ADDR, &addr, 1) != 0) { 00168 return -1; 00169 } 00170 00171 if (i2c_->read(I2C_ADDR, byte, 3) != 0) { 00172 return -1; 00173 } 00174 00175 up = ((byte[0] << 16) | (byte[1] << 8) | byte[2]) >> (8 - oss_); 00176 00177 b6 = b5 - 4000; 00178 x1 = (b6 * b6) >> 12; 00179 x1 *= calib.b2; 00180 x1 >>= 11; 00181 x2 = calib.ac2 * b6; 00182 x2 >>= 11; 00183 x3 = x1 + x2; 00184 b3 = (((((int32_t)calib.ac1) * 4 + x3) << oss_) + 2); 00185 b3 >>= 2; 00186 00187 x1 = (calib.ac3 * b6) >> 13; 00188 x2 = (calib.b1 * ((b6 * b6) >> 12)) >> 16; 00189 x3 = (x1 + x2 + 2) >> 2; 00190 b4 = (calib.ac4 * (uint32_t)(x3 + 32768)) >> 15; 00191 b7 = ((uint32_t)up - b3) * (50000 >> oss_); 00192 p = ((b7 < 0x80000000) ? ((b7 << 1) / b4) : ((b7 / b4) * 2)); 00193 x1 = p >> 8; 00194 x1 *= x1; 00195 x1 = (x1 * 3038) >> 16; 00196 x2 = (-7357 * p) >> 16; 00197 p += (x1 + x2 + 3791) >> 4; 00198 00199 *pressure = p; 00200 00201 return 0; 00202 } 00203 00204 //****************************************************************************** 00205 int BMP180::startTemperature(void) 00206 { 00207 char data[2] = { REG_ADDR_CTRL, CTRL_REG_TEMP }; 00208 00209 if (i2c_->write(I2C_ADDR, data, 2) != 0) { 00210 return -1; 00211 } 00212 00213 return 0; 00214 } 00215 00216 //****************************************************************************** 00217 int BMP180::getTemperature(float *tempC) 00218 { 00219 char addr, byte[2]; 00220 uint16_t ut; 00221 int32_t x1, x2; 00222 00223 addr = REG_ADDR_DATA; 00224 if (i2c_->write(I2C_ADDR, &addr, 1) != 0) { 00225 return -1; 00226 } 00227 00228 if (i2c_->read(I2C_ADDR, byte, 2) != 0) { 00229 return -1; 00230 } 00231 00232 ut = (byte[0] << 8) | byte[1]; 00233 00234 x1 = ((ut - calib.ac6) * calib.ac5) >> 15; 00235 x2 = (calib.mc << 11) / (x1 + calib.md); 00236 b5 = x1 + x2; 00237 00238 *tempC = (float)(b5 + 8) / 160; 00239 00240 return 0; 00241 } 00242 00243 //****************************************************************************** 00244 int BMP180::getTemperature(int16_t *tempCx10) 00245 { 00246 char addr, byte[2]; 00247 uint16_t ut; 00248 int32_t x1, x2; 00249 00250 addr = REG_ADDR_DATA; 00251 if (i2c_->write(I2C_ADDR, &addr, 1) != 0) { 00252 return -1; 00253 } 00254 00255 if (i2c_->read(I2C_ADDR, byte, 2) != 0) { 00256 return -1; 00257 } 00258 00259 ut = (byte[0] << 8) | byte[1]; 00260 00261 x1 = ((ut - calib.ac6) * calib.ac5) >> 15; 00262 x2 = (calib.mc << 11) / (x1 + calib.md); 00263 b5 = x1 + x2; 00264 00265 *tempCx10 = (b5 + 8) >> 4; 00266 00267 return 0; 00268 }
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