High resolution barometer and altimeter using i2c mode
Dependents: mbed_5637_test Weather_Station_Ofiicial
Fork of ms5611 by
Diff: ms5561.cpp
- Revision:
- 8:3a9d37268ccd
- Parent:
- 7:2e8bc98f3dda
--- a/ms5561.cpp Tue May 20 16:13:09 2014 +0000 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000 @@ -1,355 +0,0 @@ -//! -//! @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 "ms5561.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 - -ms5611::ms5611(PinName sda, PinName scl) : _i2c(sda, scl) { - _i2c.frequency(400000); -} - -//******************************************************** -//! @brief send I2C start condition and the address byte -//! -//! @return 0 -//******************************************************** - -int ms5611::m_i2c_start(bool readMode) { - int twst; - _i2c.start(); - if(readMode == true) { - twst = m_i2c_write(MS5611_ADDR_R); - } else { - twst = m_i2c_write(MS5611_ADDR_W); - } - return(twst); -} - -//******************************************************** -//! @brief send I2C stop condition -//! -//! @return none -//******************************************************** - -void ms5611::m_i2c_stop(void) { - _i2c.stop(); -} - -//******************************************************** -//! @brief send I2C stop condition -//! -//! @return remote ack status -//******************************************************** - -unsigned char ms5611::m_i2c_write(unsigned char data) { - int twst = _i2c.write(data); - return(twst); -} - -//******************************************************** -//! @brief read I2C byte with acknowledgment -//! -//! @return read byte -//******************************************************** - -unsigned char ms5611::m_i2c_readAck(void) { - int twst = _i2c.read(1); - return(twst); -} - -//******************************************************** -//! @brief read I2C byte without acknowledgment -//! -//! @return read byte -//******************************************************** - -unsigned char ms5611::m_i2c_readNak(void) { - int twst = _i2c.read(0); - return(twst); -} - -//******************************************************** -//! @brief send command using I2C hardware interface -//! -//! @return none -//******************************************************** - -void ms5611::m_i2c_send(char cmd) { - unsigned char 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() { - m_i2c_send(MS5611_CMD_RESET); - wait_ms(4); - loadCoefs(); -} - -//******************************************************** -//! @brief preform adc conversion -//! -//! @return 24bit result -//******************************************************** - -unsigned long ms5611::cmd_adc(char cmd) { - char cobuf[3]; - cobuf[0] = 0; - cobuf[1] = 0; - cobuf[2] = 0; - unsigned int ret; - unsigned long temp = 0; - m_i2c_send(MS5611_CMD_ADC_CONV + cmd); - 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; - } - m_i2c_send(MS5611_CMD_ADC_READ); - - ret = _i2c.read(MS5611_ADDR_R, cobuf, 3, false); - if(ret) printf("\n*** ms5611 ADC Read Error "); - temp = (cobuf[0] << 16) + (cobuf[1] << 8) + cobuf[2]; - return temp; -} - -//******************************************************** -//! @brief Read calibration coefficients -//! -//! @return coefficient -//******************************************************** - -unsigned int ms5611::cmd_prom(char coef_num) { - char cobuf[2]; - unsigned int ret; - unsigned int rC = 0; - cobuf[0] = 0; - cobuf[1] = 0; - m_i2c_send(MS5611_CMD_PROM_RD + coef_num * 2); // send PROM READ command - ret = _i2c.read(MS5611_ADDR_R, cobuf, 2, false); - if(ret) printf("\n*** ms5611 PROM Read Error "); - rC = cobuf[0] * 256 + cobuf[1]; - return rC; -} - -//******************************************************** -//! @brief calculate the CRC code -//! -//! @return crc code -//******************************************************** - -unsigned char ms5611::crc4(unsigned int n_prom[]) { - unsigned int n_rem; - unsigned int crc_read; - unsigned char 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 ^= (unsigned short) ((n_prom[cnt>>1]) & 0x00FF); - } else { - n_rem ^= (unsigned short) (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: -unsigned int 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 -//******************************************************** - -void ms5611::loadCoefs() { - for (int i = 0; i < 8; i++){ - wait_ms(50); - C[i] = cmd_prom(i); - } - unsigned char 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] << 17) + ((dT * (C[4]) >> 6)); //was OFF = (C[2] << 17) + dT * C[4] / (1 << 6); - int64_t SENS = ((uint32_t)C[1] << 16) + ((dT * (C[3]) >> 7)); //was SENS = (C[1] << 16) + dT * C[3] / (1 << 7); - //T = (2000 + (((uint64_t)dT * C[6]) / (float)(1 << 23))) / 100; - T=(2000+(dT*C[6])/8388608)/100; - //int32_t TEMP = 2000 + (int64_t)dT * (int64_t)C[6] / (int64_t)(1 << 23); - int32_t TEMP = 2000 + (int64_t)dT * (int64_t)(C[6] >> 23); - if(TEMP < 2000) { // if temperature lower than 20 Celsius - float T1 = (TEMP - 2000) * (TEMP - 2000); - int64_t OFF1 = (61 * T1) / 16; - int64_t SENS1 = (29 * T1) / 16; - - if(TEMP < -1500) { // if temperature lower than -15 Celsius - T1 = (TEMP + 1500) * (TEMP + 1500); - OFF1 += 17 * T1; - SENS1 += 9 * T1 ; - } - OFF -= OFF1; - SENS -= SENS1; - T = (float)TEMP / 100; - } -// int64_t P1 = ((((int64_t)D1 * SENS) >> 21) - OFF) >> 15; - //P = ((((int64_t)D1 * SENS ) >> 21) - OFF) / (double) (1 << 15) / 100.0; - P=(D1*SENS/2097152-OFF)/3276800; -} - -//******************************************************** -//! @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); -}