High resolution barometer and altimeter using i2c mode
Dependents: upverter_fitbit_clone ReadingMag_HMC5883L_work
ms5611.cpp
- Committer:
- loopsva
- Date:
- 2016-11-11
- Revision:
- 12:e9a90b8c8688
- Parent:
- 11:e0417b67a4b5
File content as of revision 12:e9a90b8c8688:
//! //! @file an520_I2C.c,v //! //! Copyright (c) 2009 MEAS Switzerland //! //! //! //! @brief This C code is for starter reference only. It is written for the //! MEAS Switzerland MS56xx pressure sensor modules and Atmel Atmega644p //! microcontroller. //! //! @version 1.0 $Id: an520_I2C.c,v 1.0 //! //! @todo #include "mbed.h" #include "ms5611.h" double P; // compensated pressure value (mB) double T; // compensated temperature value (degC) double A; // altitude (ft) double S; // sea level barometer (mB) //uint32_t C[8]; //coefficient storage //--------------------------------------------------------------------------------------------------------------------------------------// // Constructor and destructor - default to be compatible with legacy m5611 driver ms5611::ms5611(PinName sda, PinName scl) : _i2c(sda, scl) { _i2c.frequency(400000); _i2cWAddr = MS5611_ADDR_W; _i2cRAddr = MS5611_ADDR_R; } //--------------------------------------------------------------------------------------------------------------------------------------// // Constructor and destructor - new, to allow for user to select i2c address based on CSB pin ms5611::ms5611(PinName sda, PinName scl, CSBpolarity CSBpin) : _i2c(sda, scl) { _i2c.frequency(400000); _i2cWAddr = MS5611_ADDR_W; _i2cRAddr = MS5611_ADDR_R; if(CSBpin == CSBpin_1) { _i2cWAddr -= 2; _i2cRAddr -= 2; } } //******************************************************** //! @brief send I2C start condition and the address byte //! //! @return 0 //******************************************************** int32_t ms5611::m_i2c_start(bool readMode) { int32_t twst; _i2c.start(); if(readMode == true) { twst = m_i2c_write(_i2cRAddr); } else { twst = m_i2c_write(_i2cWAddr); } return(twst); } //******************************************************** //! @brief send I2C stop condition //! //! @return none //******************************************************** void ms5611::m_i2c_stop() { _i2c.stop(); } //******************************************************** //! @brief send I2C stop condition //! //! @return remote ack status //******************************************************** uint8_t ms5611::m_i2c_write(uint8_t data) { uint8_t twst = _i2c.write(data); return(twst); } //******************************************************** //! @brief read I2C byte with acknowledgment //! //! @return read byte //******************************************************** uint8_t ms5611::m_i2c_readAck() { uint8_t twst = _i2c.read(1); return(twst); } //******************************************************** //! @brief read I2C byte without acknowledgment //! //! @return read byte //******************************************************** uint8_t ms5611::m_i2c_readNak() { uint8_t twst = _i2c.read(0); return(twst); } //******************************************************** //! @brief send command using I2C hardware interface //! //! @return none //******************************************************** void ms5611::m_i2c_send(uint8_t cmd) { uint8_t ret; ret = m_i2c_start(false); if(!(ret)) { m_i2c_stop(); } else { ret = m_i2c_write(cmd); m_i2c_stop(); } } //******************************************************** //! @brief send reset sequence //! //! @return none //******************************************************** void ms5611::cmd_reset() { #if defined MS5611i2cLOWLEVEL m_i2c_send(MS5611_CMD_RESET); #else cobuf[0] = MS5611_CMD_RESET; _i2c.write(_i2cWAddr, cobuf, 1, false); #endif wait_ms(4); loadCoefs(); } //******************************************************** //! @brief preform adc conversion //! //! @return 24bit result //******************************************************** uint64_t ms5611::cmd_adc(uint8_t cmd) { uint64_t temp = 0; #if defined MS5611i2cLOWLEVEL m_i2c_send(MS5611_CMD_ADC_CONV + cmd); #else cobuf[0] = 0; cobuf[1] = 0; cobuf[2] = 0; cobuf[0] = MS5611_CMD_ADC_CONV + cmd; _i2c.write(_i2cWAddr, cobuf, 1, false); #endif switch (cmd & 0x0f) { case MS5611_CMD_ADC_256 : wait_us(900); break; case MS5611_CMD_ADC_512 : wait_ms(3); break; case MS5611_CMD_ADC_1024: wait_ms(4); break; case MS5611_CMD_ADC_2048: wait_ms(6); break; case MS5611_CMD_ADC_4096: wait_ms(10); break; } #if defined MS5611i2cLOWLEVEL m_i2c_send(MS5611_CMD_ADC_READ); m_i2c_start(true); temp = m_i2c_readAck(); temp = (temp << 8) | m_i2c_readAck(); temp = (temp << 8) | m_i2c_readNak(); m_i2c_stop(); #else cobuf[0] = MS5611_CMD_ADC_READ; _i2c.write(_i2cWAddr, cobuf, 1, true); cobuf[0] = 0; _i2c.read(_i2cRAddr, cobuf, 3, false); temp = (cobuf[0] << 16) | (cobuf[1] << 8) | cobuf[2]; #endif return temp; } //******************************************************** //! @brief Read calibration coefficients //! //! @return coefficient //******************************************************** uint32_t ms5611::cmd_prom(uint8_t coef_num) { uint32_t rC = 0; #if defined MS5611i2cLOWLEVEL m_i2c_send(MS5611_CMD_PROM_RD + coef_num * 2); // send PROM READ command m_i2c_start(true); rC = m_i2c_readAck(); rC = (rC << 8) | m_i2c_readNak(); m_i2c_stop(); #else cobuf[0] = 0; cobuf[1] = 0; cobuf[0] = MS5611_CMD_PROM_RD + coef_num * 2; _i2c.write(_i2cWAddr, cobuf, 1, true); cobuf[0] = 0; _i2c.read(_i2cRAddr, cobuf, 2, false); rC = (cobuf[0] << 8) | cobuf[1]; #endif return rC; } //******************************************************** //! @brief calculate the CRC code //! //! @return crc code //******************************************************** uint8_t ms5611::crc4(uint32_t n_prom[]) { uint32_t n_rem; uint32_t crc_read; uint8_t n_bit; n_rem = 0x00; crc_read = n_prom[7]; n_prom[7]=(0xFF00 & (n_prom[7])); for (int cnt = 0; cnt < 16; cnt++) { if (cnt%2 == 1) { n_rem ^= (uint16_t) ((n_prom[cnt>>1]) & 0x00FF); } else { n_rem ^= (uint16_t) (n_prom[cnt>>1]>>8); } for (n_bit = 8; n_bit > 0; n_bit--) { if (n_rem & (0x8000)) { n_rem = (n_rem << 1) ^ 0x3000; } else { n_rem = (n_rem << 1); } } } n_rem= (0x000F & (n_rem >> 12)); n_prom[7]=crc_read; return (n_rem ^ 0x0); } /* The CRC code is calculated and written in factory with the LSB byte in the prom n_prom[7] set to 0x00 (see Coefficient table below). It is thus important to clear those bytes from the calculation buffer before proceeding with the CRC calculation itself: n_prom[7]=(0xFF00 & (n_prom[7])); //CRC byte is replaced by 0 As a simple test of the CRC code, the following coefficient table could be used: uint32_t nprom[] = {0x3132,0x3334,0x3536,0x3738,0x3940,0x4142,0x4344,0x4500}; the resulting calculated CRC should be 0xB. DB 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Addr 0 16 bit reserved for manufacturer 1 Coefficient 1 (16 bit unsigned) 2 Coefficient 2 (16 bit unsigned) 3 Coefficient 3 (16 bit unsigned) 4 Coefficient 4 (16 bit unsigned) 5 Coefficient 5 (16 bit unsigned) 6 Coefficient 6 (16 bit unsigned) 7 0 0 0 0 CRC(0x0) */ /* //Returns 0x0b as per AP520_004 C[0] = 0x3132; C[1] = 0x3334; C[2] = 0x3536; C[3] = 0x3738; C[4] = 0x3940; C[5] = 0x4142; C[6] = 0x4344; C[7] = 0x4546; n_crc = ms.crc4(C); // calculate the CRC pc.printf("testing CRC: 0x%x\n", n_crc); */ //******************************************************** //! @brief load all calibration coefficients //! //! @return none //******************************************************** extern RawSerial pc; void ms5611::loadCoefs() { pc.printf("\r\n - Coefs: "); for (int i = 0; i < 8; i++){ wait_ms(50); C[i] = cmd_prom(i); pc.printf("%04x ", C[i]); } pc.printf("\r\n"); uint8_t n_crc = crc4(C); } //******************************************************** //! @brief calculate temperature and pressure //! //! @return none //******************************************************** void ms5611::calcPT() { int32_t D2 = cmd_adc(MS5611_CMD_ADC_D2 + MS5611_CMD_ADC_4096); // read D2 int32_t D1 = cmd_adc(MS5611_CMD_ADC_D1 + MS5611_CMD_ADC_4096); // read D1 int64_t dT = D2 - ((uint64_t)C[5] << 8); int64_t OFF = ((uint32_t)C[2] << 16) + ((dT * (C[4]) >> 7)); //was OFF = (C[2] << 17) + dT * C[4] / (1 << 6); int64_t SENS = ((uint32_t)C[1] << 15) + ((dT * (C[3]) >> 8)); //was SENS = (C[1] << 16) + dT * C[3] / (1 << 7); int32_t TEMP = 2000 + (int64_t)dT * (int64_t)C[6] / (int64_t)(1 << 23); T = (double) TEMP / 100.0; if(TEMP < 2000) { // if temperature lower than +20 Celsius int64_t T1 = ((int64_t)TEMP - 2000) * ((int64_t)TEMP - 2000); int64_t OFF1 = (5 * T1) >> 1; int64_t SENS1 = (5 * T1) >> 2; if(TEMP < -1500) { // if temperature lower than -15 Celsius T1 = ((int64_t)TEMP + 1500) * ((int64_t)TEMP + 1500); OFF1 += 7 * T1; SENS1 += 11 * T1 >> 1; } OFF -= OFF1; SENS -= SENS1; } P = (double)(((((int64_t)D1 * SENS ) >> 21) - OFF) / (double) (1 << 15)) / 100.0; } //******************************************************** //! @brief calculate temperature //! //! @return double temperature degC //******************************************************** double ms5611::calcTemp() { calcPT(); return(T); } //******************************************************** //! @brief calculate pressure //! //! @return double barometric pressure millibar //******************************************************** double ms5611::calcPressure() { calcPT(); return(P); } //******************************************************** //! @brief get pressure, no calculation //! //! @return double barometric pressure millibar //******************************************************** double ms5611::getPressure() { calcPT(); return(P); } //******************************************************** //! @brief get altitude from known sea level barometer, //! @ no pre-pressure calculation //! //! @enter float sea level barometer //! @return float altitude in feet //******************************************************** float ms5611::getAltitudeFT(float sea_pressure) { A = (1 - (pow((P / (double)sea_pressure), 0.190284))) * 145366.45; return((float)A); } //******************************************************** //! @brief get sea level pressure from known altitude(ft), //! @ no pre-pressure calculation //! //! @enter float known altitude in feet //! @return float seal level barometer in mb //******************************************************** float ms5611::getSeaLevelBaroFT(float known_alt) { S = pow(pow((P * INHG), 0.190284) + 0.00001313 * known_alt , 5.2553026) * MB; return((float)S); } //******************************************************** //! @brief get sea level pressure from known altitude(m), //! @ no pre-pressure calculation //! //! @enter float known altitude in meters //! @return float seal level barometer in mb //******************************************************** float ms5611::getSeaLevelBaroM(float known_alt) { S = pow(pow((P * INHG), 0.190284) + 0.00001313 * known_alt * FTMETERS , 5.2553026) * MB; return((float)S); }