Kevin Braun / ms5611

High resolution barometer and altimeter using i2c mode

Dependents:   upverter_fitbit_clone ReadingMag_HMC5883L_work

ms5611.cpp@7:90ee2168baa7, 2014-12-22 (annotated)

Committer:
loopsva
Date:
Mon Dec 22 23:38:34 2014 +0000
Revision:
7:90ee2168baa7
Parent:
6:41c370fa1f7b
Child:
8:461f68bc94f2
Added second constructor so user can choose the polarity of the ms5611's CSB pin.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
loopsva 0:f97f410d4a21 1 //!
loopsva 0:f97f410d4a21 2 //! @file an520_I2C.c,v
loopsva 0:f97f410d4a21 3 //!
loopsva 0:f97f410d4a21 4 //! Copyright (c) 2009 MEAS Switzerland
loopsva 0:f97f410d4a21 5 //!
loopsva 0:f97f410d4a21 6 //!
loopsva 0:f97f410d4a21 7 //!
loopsva 0:f97f410d4a21 8 //! @brief This C code is for starter reference only. It is written for the
loopsva 0:f97f410d4a21 9 //! MEAS Switzerland MS56xx pressure sensor modules and Atmel Atmega644p
loopsva 0:f97f410d4a21 10 //! microcontroller.
loopsva 0:f97f410d4a21 11 //!
loopsva 0:f97f410d4a21 12 //! @version 1.0 $Id: an520_I2C.c,v 1.0
loopsva 0:f97f410d4a21 13 //!
loopsva 0:f97f410d4a21 14 //! @todo
loopsva 0:f97f410d4a21 15
loopsva 0:f97f410d4a21 16 #include "mbed.h"
loopsva 0:f97f410d4a21 17 #include "ms5611.h"
loopsva 0:f97f410d4a21 18
loopsva 5:0d7b229474c6 19 double P; // compensated pressure value (mB)
loopsva 5:0d7b229474c6 20 double T; // compensated temperature value (degC)
loopsva 5:0d7b229474c6 21 double A; // altitude (ft)
loopsva 5:0d7b229474c6 22 double S; // sea level barometer (mB)
loopsva 2:05804ed70748 23
loopsva 2:05804ed70748 24 uint32_t C[8]; //coefficient storage
loopsva 2:05804ed70748 25
loopsva 0:f97f410d4a21 26 //--------------------------------------------------------------------------------------------------------------------------------------//
loopsva 7:90ee2168baa7 27 // Constructor and destructor - default to be compatible with legacy m5611 driver
loopsva 0:f97f410d4a21 28
loopsva 0:f97f410d4a21 29 ms5611::ms5611(PinName sda, PinName scl) : _i2c(sda, scl) {
loopsva 6:41c370fa1f7b 30 _i2c.frequency(400000);
loopsva 7:90ee2168baa7 31 _i2cWAddr = MS5611_ADDR_W;
loopsva 7:90ee2168baa7 32 _i2cRAddr = MS5611_ADDR_R;
loopsva 7:90ee2168baa7 33 }
loopsva 7:90ee2168baa7 34
loopsva 7:90ee2168baa7 35 //--------------------------------------------------------------------------------------------------------------------------------------//
loopsva 7:90ee2168baa7 36 // Constructor and destructor - new, to allow for user to select i2c address based on CSB pin
loopsva 7:90ee2168baa7 37
loopsva 7:90ee2168baa7 38 ms5611::ms5611(PinName sda, PinName scl, CSBpolarity CSBpin) : _i2c(sda, scl) {
loopsva 7:90ee2168baa7 39 _i2c.frequency(400000);
loopsva 7:90ee2168baa7 40 _i2cWAddr = MS5611_ADDR_W;
loopsva 7:90ee2168baa7 41 _i2cRAddr = MS5611_ADDR_R;
loopsva 7:90ee2168baa7 42 if(CSBpin == CSBpin_1) {
loopsva 7:90ee2168baa7 43 _i2cWAddr -= 2;
loopsva 7:90ee2168baa7 44 _i2cRAddr -= 2;
loopsva 7:90ee2168baa7 45
loopsva 7:90ee2168baa7 46 }
loopsva 0:f97f410d4a21 47 }
loopsva 0:f97f410d4a21 48
loopsva 0:f97f410d4a21 49 //********************************************************
loopsva 0:f97f410d4a21 50 //! @brief send I2C start condition and the address byte
loopsva 0:f97f410d4a21 51 //!
loopsva 0:f97f410d4a21 52 //! @return 0
loopsva 0:f97f410d4a21 53 //********************************************************
loopsva 0:f97f410d4a21 54
loopsva 0:f97f410d4a21 55 int ms5611::m_i2c_start(bool readMode) {
loopsva 0:f97f410d4a21 56 int twst;
loopsva 0:f97f410d4a21 57 _i2c.start();
loopsva 0:f97f410d4a21 58 if(readMode == true) {
loopsva 7:90ee2168baa7 59 twst = m_i2c_write(_i2cRAddr);
loopsva 0:f97f410d4a21 60 } else {
loopsva 7:90ee2168baa7 61 twst = m_i2c_write(_i2cWAddr);
loopsva 0:f97f410d4a21 62 }
loopsva 0:f97f410d4a21 63 return(twst);
loopsva 0:f97f410d4a21 64 }
loopsva 0:f97f410d4a21 65
loopsva 0:f97f410d4a21 66 //********************************************************
loopsva 0:f97f410d4a21 67 //! @brief send I2C stop condition
loopsva 0:f97f410d4a21 68 //!
loopsva 0:f97f410d4a21 69 //! @return none
loopsva 0:f97f410d4a21 70 //********************************************************
loopsva 0:f97f410d4a21 71
loopsva 0:f97f410d4a21 72 void ms5611::m_i2c_stop(void) {
loopsva 0:f97f410d4a21 73 _i2c.stop();
loopsva 0:f97f410d4a21 74 }
loopsva 0:f97f410d4a21 75
loopsva 0:f97f410d4a21 76 //********************************************************
loopsva 0:f97f410d4a21 77 //! @brief send I2C stop condition
loopsva 0:f97f410d4a21 78 //!
loopsva 0:f97f410d4a21 79 //! @return remote ack status
loopsva 0:f97f410d4a21 80 //********************************************************
loopsva 0:f97f410d4a21 81
loopsva 0:f97f410d4a21 82 unsigned char ms5611::m_i2c_write(unsigned char data) {
loopsva 0:f97f410d4a21 83 int twst = _i2c.write(data);
loopsva 0:f97f410d4a21 84 return(twst);
loopsva 0:f97f410d4a21 85 }
loopsva 0:f97f410d4a21 86
loopsva 0:f97f410d4a21 87 //********************************************************
loopsva 0:f97f410d4a21 88 //! @brief read I2C byte with acknowledgment
loopsva 0:f97f410d4a21 89 //!
loopsva 0:f97f410d4a21 90 //! @return read byte
loopsva 0:f97f410d4a21 91 //********************************************************
loopsva 0:f97f410d4a21 92
loopsva 0:f97f410d4a21 93 unsigned char ms5611::m_i2c_readAck(void) {
loopsva 0:f97f410d4a21 94 int twst = _i2c.read(1);
loopsva 0:f97f410d4a21 95 return(twst);
loopsva 0:f97f410d4a21 96 }
loopsva 0:f97f410d4a21 97
loopsva 0:f97f410d4a21 98 //********************************************************
loopsva 0:f97f410d4a21 99 //! @brief read I2C byte without acknowledgment
loopsva 0:f97f410d4a21 100 //!
loopsva 0:f97f410d4a21 101 //! @return read byte
loopsva 0:f97f410d4a21 102 //********************************************************
loopsva 0:f97f410d4a21 103
loopsva 0:f97f410d4a21 104 unsigned char ms5611::m_i2c_readNak(void) {
loopsva 0:f97f410d4a21 105 int twst = _i2c.read(0);
loopsva 0:f97f410d4a21 106 return(twst);
loopsva 0:f97f410d4a21 107 }
loopsva 0:f97f410d4a21 108
loopsva 0:f97f410d4a21 109 //********************************************************
loopsva 0:f97f410d4a21 110 //! @brief send command using I2C hardware interface
loopsva 0:f97f410d4a21 111 //!
loopsva 0:f97f410d4a21 112 //! @return none
loopsva 0:f97f410d4a21 113 //********************************************************
loopsva 0:f97f410d4a21 114
loopsva 0:f97f410d4a21 115 void ms5611::m_i2c_send(char cmd) {
loopsva 0:f97f410d4a21 116 unsigned char ret;
loopsva 2:05804ed70748 117 ret = m_i2c_start(false);
loopsva 2:05804ed70748 118 if(!(ret)) {
loopsva 0:f97f410d4a21 119 m_i2c_stop();
loopsva 2:05804ed70748 120 } else {
loopsva 0:f97f410d4a21 121 ret = m_i2c_write(cmd);
loopsva 0:f97f410d4a21 122 m_i2c_stop();
loopsva 0:f97f410d4a21 123 }
loopsva 0:f97f410d4a21 124 }
loopsva 0:f97f410d4a21 125
loopsva 0:f97f410d4a21 126 //********************************************************
loopsva 0:f97f410d4a21 127 //! @brief send reset sequence
loopsva 0:f97f410d4a21 128 //!
loopsva 0:f97f410d4a21 129 //! @return none
loopsva 0:f97f410d4a21 130 //********************************************************
loopsva 0:f97f410d4a21 131
loopsva 0:f97f410d4a21 132 void ms5611::cmd_reset() {
loopsva 2:05804ed70748 133 m_i2c_send(MS5611_CMD_RESET);
loopsva 2:05804ed70748 134 wait_ms(4);
loopsva 0:f97f410d4a21 135 loadCoefs();
loopsva 0:f97f410d4a21 136 }
loopsva 0:f97f410d4a21 137
loopsva 0:f97f410d4a21 138 //********************************************************
loopsva 0:f97f410d4a21 139 //! @brief preform adc conversion
loopsva 0:f97f410d4a21 140 //!
loopsva 0:f97f410d4a21 141 //! @return 24bit result
loopsva 0:f97f410d4a21 142 //********************************************************
loopsva 0:f97f410d4a21 143
loopsva 0:f97f410d4a21 144 unsigned long ms5611::cmd_adc(char cmd) {
loopsva 0:f97f410d4a21 145 char cobuf[3];
loopsva 0:f97f410d4a21 146 cobuf[0] = 0;
loopsva 0:f97f410d4a21 147 cobuf[1] = 0;
loopsva 0:f97f410d4a21 148 cobuf[2] = 0;
loopsva 0:f97f410d4a21 149 unsigned int ret;
loopsva 0:f97f410d4a21 150 unsigned long temp = 0;
loopsva 2:05804ed70748 151 m_i2c_send(MS5611_CMD_ADC_CONV + cmd);
loopsva 2:05804ed70748 152 switch (cmd & 0x0f) {
loopsva 0:f97f410d4a21 153 case MS5611_CMD_ADC_256 : wait_us(900); break;
loopsva 0:f97f410d4a21 154 case MS5611_CMD_ADC_512 : wait_ms(3); break;
loopsva 0:f97f410d4a21 155 case MS5611_CMD_ADC_1024: wait_ms(4); break;
loopsva 0:f97f410d4a21 156 case MS5611_CMD_ADC_2048: wait_ms(6); break;
loopsva 0:f97f410d4a21 157 case MS5611_CMD_ADC_4096: wait_ms(10); break;
loopsva 0:f97f410d4a21 158 }
loopsva 0:f97f410d4a21 159 m_i2c_send(MS5611_CMD_ADC_READ);
loopsva 0:f97f410d4a21 160
loopsva 7:90ee2168baa7 161 ret = _i2c.read(_i2cRAddr, cobuf, 3, false);
loopsva 0:f97f410d4a21 162 if(ret) printf("\n*** ms5611 ADC Read Error ");
loopsva 0:f97f410d4a21 163 temp = (cobuf[0] << 16) + (cobuf[1] << 8) + cobuf[2];
loopsva 0:f97f410d4a21 164 return temp;
loopsva 0:f97f410d4a21 165 }
loopsva 0:f97f410d4a21 166
loopsva 0:f97f410d4a21 167 //********************************************************
loopsva 0:f97f410d4a21 168 //! @brief Read calibration coefficients
loopsva 0:f97f410d4a21 169 //!
loopsva 0:f97f410d4a21 170 //! @return coefficient
loopsva 0:f97f410d4a21 171 //********************************************************
loopsva 0:f97f410d4a21 172
loopsva 0:f97f410d4a21 173 unsigned int ms5611::cmd_prom(char coef_num) {
loopsva 0:f97f410d4a21 174 char cobuf[2];
loopsva 0:f97f410d4a21 175 unsigned int ret;
loopsva 0:f97f410d4a21 176 unsigned int rC = 0;
loopsva 0:f97f410d4a21 177 cobuf[0] = 0;
loopsva 0:f97f410d4a21 178 cobuf[1] = 0;
loopsva 0:f97f410d4a21 179 m_i2c_send(MS5611_CMD_PROM_RD + coef_num * 2); // send PROM READ command
loopsva 7:90ee2168baa7 180 ret = _i2c.read(_i2cRAddr, cobuf, 2, false);
loopsva 0:f97f410d4a21 181 if(ret) printf("\n*** ms5611 PROM Read Error ");
loopsva 0:f97f410d4a21 182 rC = cobuf[0] * 256 + cobuf[1];
loopsva 0:f97f410d4a21 183 return rC;
loopsva 0:f97f410d4a21 184 }
loopsva 0:f97f410d4a21 185
loopsva 0:f97f410d4a21 186 //********************************************************
loopsva 0:f97f410d4a21 187 //! @brief calculate the CRC code
loopsva 0:f97f410d4a21 188 //!
loopsva 0:f97f410d4a21 189 //! @return crc code
loopsva 0:f97f410d4a21 190 //********************************************************
loopsva 0:f97f410d4a21 191
loopsva 0:f97f410d4a21 192 unsigned char ms5611::crc4(unsigned int n_prom[]) {
loopsva 2:05804ed70748 193 unsigned int n_rem;
loopsva 2:05804ed70748 194 unsigned int crc_read;
loopsva 0:f97f410d4a21 195 unsigned char n_bit;
loopsva 0:f97f410d4a21 196 n_rem = 0x00;
loopsva 2:05804ed70748 197 crc_read = n_prom[7];
loopsva 2:05804ed70748 198 n_prom[7]=(0xFF00 & (n_prom[7]));
loopsva 2:05804ed70748 199 for (int cnt = 0; cnt < 16; cnt++) {
loopsva 0:f97f410d4a21 200 if (cnt%2 == 1) {
loopsva 0:f97f410d4a21 201 n_rem ^= (unsigned short) ((n_prom[cnt>>1]) & 0x00FF);
loopsva 0:f97f410d4a21 202 } else {
loopsva 0:f97f410d4a21 203 n_rem ^= (unsigned short) (n_prom[cnt>>1]>>8);
loopsva 0:f97f410d4a21 204 }
loopsva 0:f97f410d4a21 205 for (n_bit = 8; n_bit > 0; n_bit--) {
loopsva 0:f97f410d4a21 206 if (n_rem & (0x8000)) {
loopsva 0:f97f410d4a21 207 n_rem = (n_rem << 1) ^ 0x3000;
loopsva 0:f97f410d4a21 208 } else {
loopsva 0:f97f410d4a21 209 n_rem = (n_rem << 1);
loopsva 0:f97f410d4a21 210 }
loopsva 0:f97f410d4a21 211 }
loopsva 0:f97f410d4a21 212 }
loopsva 2:05804ed70748 213 n_rem= (0x000F & (n_rem >> 12));
loopsva 2:05804ed70748 214 n_prom[7]=crc_read;
loopsva 0:f97f410d4a21 215 return (n_rem ^ 0x0);
loopsva 2:05804ed70748 216 }
loopsva 2:05804ed70748 217
loopsva 0:f97f410d4a21 218 /*
loopsva 0:f97f410d4a21 219 The CRC code is calculated and written in factory with the LSB byte in the prom n_prom[7] set to 0x00 (see
loopsva 0:f97f410d4a21 220 Coefficient table below). It is thus important to clear those bytes from the calculation buffer before proceeding
loopsva 0:f97f410d4a21 221 with the CRC calculation itself:
loopsva 0:f97f410d4a21 222 n_prom[7]=(0xFF00 & (n_prom[7])); //CRC byte is replaced by 0
loopsva 0:f97f410d4a21 223 As a simple test of the CRC code, the following coefficient table could be used:
loopsva 0:f97f410d4a21 224 unsigned int nprom[] = {0x3132,0x3334,0x3536,0x3738,0x3940,0x4142,0x4344,0x4500};
loopsva 0:f97f410d4a21 225 the resulting calculated CRC should be 0xB.
loopsva 0:f97f410d4a21 226
loopsva 0:f97f410d4a21 227 DB 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
loopsva 0:f97f410d4a21 228 Addr
loopsva 0:f97f410d4a21 229 0 16 bit reserved for manufacturer
loopsva 0:f97f410d4a21 230 1 Coefficient 1 (16 bit unsigned)
loopsva 0:f97f410d4a21 231 2 Coefficient 2 (16 bit unsigned)
loopsva 0:f97f410d4a21 232 3 Coefficient 3 (16 bit unsigned)
loopsva 0:f97f410d4a21 233 4 Coefficient 4 (16 bit unsigned)
loopsva 0:f97f410d4a21 234 5 Coefficient 5 (16 bit unsigned)
loopsva 0:f97f410d4a21 235 6 Coefficient 6 (16 bit unsigned)
loopsva 0:f97f410d4a21 236 7 0 0 0 0 CRC(0x0)
loopsva 0:f97f410d4a21 237 */
loopsva 0:f97f410d4a21 238 /*
loopsva 0:f97f410d4a21 239 //Returns 0x0b as per AP520_004
loopsva 2:05804ed70748 240 C[0] = 0x3132;
loopsva 2:05804ed70748 241 C[1] = 0x3334;
loopsva 2:05804ed70748 242 C[2] = 0x3536;
loopsva 2:05804ed70748 243 C[3] = 0x3738;
loopsva 2:05804ed70748 244 C[4] = 0x3940;
loopsva 2:05804ed70748 245 C[5] = 0x4142;
loopsva 2:05804ed70748 246 C[6] = 0x4344;
loopsva 2:05804ed70748 247 C[7] = 0x4546;
loopsva 0:f97f410d4a21 248 n_crc = ms.crc4(C); // calculate the CRC
loopsva 0:f97f410d4a21 249 pc.printf("testing CRC: 0x%x\n", n_crc);
loopsva 0:f97f410d4a21 250 */
loopsva 2:05804ed70748 251
loopsva 0:f97f410d4a21 252 //********************************************************
loopsva 0:f97f410d4a21 253 //! @brief load all calibration coefficients
loopsva 0:f97f410d4a21 254 //!
loopsva 0:f97f410d4a21 255 //! @return none
loopsva 0:f97f410d4a21 256 //********************************************************
loopsva 0:f97f410d4a21 257
loopsva 0:f97f410d4a21 258 void ms5611::loadCoefs() {
loopsva 0:f97f410d4a21 259 for (int i = 0; i < 8; i++){
loopsva 0:f97f410d4a21 260 wait_ms(50);
loopsva 2:05804ed70748 261 C[i] = cmd_prom(i);
loopsva 0:f97f410d4a21 262 }
loopsva 2:05804ed70748 263 unsigned char n_crc = crc4(C);
loopsva 0:f97f410d4a21 264 }
loopsva 0:f97f410d4a21 265
loopsva 0:f97f410d4a21 266 //********************************************************
loopsva 0:f97f410d4a21 267 //! @brief calculate temperature and pressure
loopsva 0:f97f410d4a21 268 //!
loopsva 0:f97f410d4a21 269 //! @return none
loopsva 0:f97f410d4a21 270 //********************************************************
loopsva 0:f97f410d4a21 271
loopsva 0:f97f410d4a21 272 void ms5611::calcPT() {
loopsva 2:05804ed70748 273 int32_t D2 = cmd_adc(MS5611_CMD_ADC_D2 + MS5611_CMD_ADC_4096); // read D2
loopsva 2:05804ed70748 274 int32_t D1 = cmd_adc(MS5611_CMD_ADC_D1 + MS5611_CMD_ADC_4096); // read D1
loopsva 3:c2d1b0d432ad 275 int64_t dT = D2 - ((uint64_t)C[5] << 8);
loopsva 2:05804ed70748 276 int64_t OFF = ((uint32_t)C[2] << 16) + ((dT * (C[4]) >> 7)); //was OFF = (C[2] << 17) + dT * C[4] / (1 << 6);
loopsva 2:05804ed70748 277 int64_t SENS = ((uint32_t)C[1] << 15) + ((dT * (C[3]) >> 8)); //was SENS = (C[1] << 16) + dT * C[3] / (1 << 7);
loopsva 2:05804ed70748 278 T = (2000 + (((uint64_t)dT * C[6]) / (float)(1 << 23))) / 100;
loopsva 2:05804ed70748 279 int32_t TEMP = 2000 + (int64_t)dT * (int64_t)C[6] / (int64_t)(1 << 23);
loopsva 0:f97f410d4a21 280
loopsva 2:05804ed70748 281 if(TEMP < 2000) { // if temperature lower than 20 Celsius
loopsva 2:05804ed70748 282 float T1 = (TEMP - 2000) * (TEMP - 2000);
loopsva 2:05804ed70748 283 int64_t OFF1 = (5 * T1) / 2;
loopsva 2:05804ed70748 284 int64_t SENS1 = (5 * T1) / 4;
loopsva 2:05804ed70748 285
loopsva 2:05804ed70748 286 if(TEMP < -1500) { // if temperature lower than -15 Celsius
loopsva 2:05804ed70748 287 T1 = (TEMP + 1500) * (TEMP + 1500);
loopsva 2:05804ed70748 288 OFF1 += 7 * T1;
loopsva 2:05804ed70748 289 SENS1 += 11 * T1 / 2;
loopsva 2:05804ed70748 290 }
loopsva 2:05804ed70748 291 OFF -= OFF1;
loopsva 2:05804ed70748 292 SENS -= SENS1;
loopsva 2:05804ed70748 293 T = (float)TEMP / 100;
loopsva 2:05804ed70748 294 }
loopsva 2:05804ed70748 295 // int64_t P1 = ((((int64_t)D1 * SENS) >> 21) - OFF) >> 15;
loopsva 2:05804ed70748 296 P = ((((int64_t)D1 * SENS ) >> 21) - OFF) / (double) (1 << 15) / 100.0;
loopsva 0:f97f410d4a21 297 }
loopsva 0:f97f410d4a21 298
loopsva 0:f97f410d4a21 299 //********************************************************
loopsva 0:f97f410d4a21 300 //! @brief calculate temperature
loopsva 0:f97f410d4a21 301 //!
loopsva 0:f97f410d4a21 302 //! @return double temperature degC
loopsva 0:f97f410d4a21 303 //********************************************************
loopsva 0:f97f410d4a21 304
loopsva 0:f97f410d4a21 305 double ms5611::calcTemp() {
loopsva 0:f97f410d4a21 306 calcPT();
loopsva 0:f97f410d4a21 307 return(T);
loopsva 0:f97f410d4a21 308 }
loopsva 0:f97f410d4a21 309
loopsva 0:f97f410d4a21 310 //********************************************************
loopsva 3:c2d1b0d432ad 311 //! @brief calculate pressure
loopsva 0:f97f410d4a21 312 //!
loopsva 0:f97f410d4a21 313 //! @return double barometric pressure millibar
loopsva 0:f97f410d4a21 314 //********************************************************
loopsva 0:f97f410d4a21 315
loopsva 0:f97f410d4a21 316 double ms5611::calcPressure() {
loopsva 0:f97f410d4a21 317 calcPT();
loopsva 0:f97f410d4a21 318 return(P);
loopsva 2:05804ed70748 319 }
loopsva 3:c2d1b0d432ad 320
loopsva 3:c2d1b0d432ad 321 //********************************************************
loopsva 3:c2d1b0d432ad 322 //! @brief get pressure, no calculation
loopsva 3:c2d1b0d432ad 323 //!
loopsva 3:c2d1b0d432ad 324 //! @return double barometric pressure millibar
loopsva 3:c2d1b0d432ad 325 //********************************************************
loopsva 3:c2d1b0d432ad 326
loopsva 3:c2d1b0d432ad 327 double ms5611::getPressure() {
loopsva 3:c2d1b0d432ad 328 calcPT();
loopsva 3:c2d1b0d432ad 329 return(P);
loopsva 3:c2d1b0d432ad 330 }
loopsva 3:c2d1b0d432ad 331
loopsva 3:c2d1b0d432ad 332 //********************************************************
loopsva 5:0d7b229474c6 333 //! @brief get altitude from known sea level barometer,
loopsva 5:0d7b229474c6 334 //! @ no pre-pressure calculation
loopsva 3:c2d1b0d432ad 335 //!
loopsva 3:c2d1b0d432ad 336 //! @enter float sea level barometer
loopsva 3:c2d1b0d432ad 337 //! @return float altitude in feet
loopsva 3:c2d1b0d432ad 338 //********************************************************
loopsva 3:c2d1b0d432ad 339
loopsva 3:c2d1b0d432ad 340 float ms5611::getAltitudeFT(float sea_pressure) {
loopsva 3:c2d1b0d432ad 341 A = (1 - (pow((P / (double)sea_pressure), 0.190284))) * 145366.45;
loopsva 3:c2d1b0d432ad 342 return((float)A);
loopsva 3:c2d1b0d432ad 343 }
loopsva 5:0d7b229474c6 344
loopsva 5:0d7b229474c6 345 //********************************************************
loopsva 5:0d7b229474c6 346 //! @brief get sea level pressure from known altitude(ft),
loopsva 5:0d7b229474c6 347 //! @ no pre-pressure calculation
loopsva 5:0d7b229474c6 348 //!
loopsva 5:0d7b229474c6 349 //! @enter float known altitude in feet
loopsva 5:0d7b229474c6 350 //! @return float seal level barometer in mb
loopsva 5:0d7b229474c6 351 //********************************************************
loopsva 5:0d7b229474c6 352
loopsva 5:0d7b229474c6 353 float ms5611::getSeaLevelBaroFT(float known_alt) {
loopsva 5:0d7b229474c6 354 S = pow(pow((P * INHG), 0.190284) + 0.00001313 * known_alt , 5.2553026) * MB;
loopsva 5:0d7b229474c6 355 return((float)S);
loopsva 5:0d7b229474c6 356 }
loopsva 5:0d7b229474c6 357
loopsva 5:0d7b229474c6 358 //********************************************************
loopsva 5:0d7b229474c6 359 //! @brief get sea level pressure from known altitude(m),
loopsva 5:0d7b229474c6 360 //! @ no pre-pressure calculation
loopsva 5:0d7b229474c6 361 //!
loopsva 5:0d7b229474c6 362 //! @enter float known altitude in meters
loopsva 5:0d7b229474c6 363 //! @return float seal level barometer in mb
loopsva 5:0d7b229474c6 364 //********************************************************
loopsva 5:0d7b229474c6 365
loopsva 5:0d7b229474c6 366 float ms5611::getSeaLevelBaroM(float known_alt) {
loopsva 5:0d7b229474c6 367 S = pow(pow((P * INHG), 0.190284) + 0.00001313 * known_alt * FTMETERS , 5.2553026) * MB;
loopsva 5:0d7b229474c6 368 return((float)S);
loopsva 5:0d7b229474c6 369 }