High resolution barometer and altimeter using i2c mode. Adapted to FreeIMU interface
Dependents: FreeIMU FreeIMU_external_magnetometer FreeIMU
Fork of ms5611 by
MS561101BA.cpp
- Committer:
- tyftyftyf
- Date:
- 2013-11-02
- Revision:
- 7:8545a1d1d1e4
- Child:
- 8:f3660f819e54
File content as of revision 7:8545a1d1d1e4:
/* MS5611-01BA.cpp - Interfaces a Measurement Specialities MS5611-01BA with Arduino See http://www.meas-spec.com/downloads/MS5611-01BA01.pdf for the device datasheet Copyright (C) 2011 Fabio Varesano <fvaresano@yahoo.it> Development of this code has been supported by the Department of Computer Science, Universita' degli Studi di Torino, Italy within the Piemonte Project http://www.piemonte.di.unito.it/ This program is free software: you can redistribute it and/or modify it under the terms of the version 3 GNU General Public License as published by the Free Software Foundation. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>. */ #include "mbed.h" #include "MS561101BA.h" #define CONVERSION_TIME 12000l // conversion time in microseconds MS561101BA::MS561101BA():i2c(I2C_SDA,I2C_SCL){ } MS561101BA::MS561101BA(I2C _i2c):i2c(_i2c) { ; } void MS561101BA::init(uint8_t address) { lastPresConv=0; lastTempConv=0; t.start(); _addr = address; reset(); // reset the device to populate its internal PROM registers wait_ms(500); // some safety time readPROM(); // reads the PROM into object variables for later use } float MS561101BA::getPressure(uint8_t OSR) { // see datasheet page 7 for formulas uint32_t rawPress = rawPressure(OSR); if(rawPress == NULL) { return NULL; } int32_t dT = getDeltaTemp(OSR); if(dT == NULL) { return NULL; } int64_t off = ((uint32_t)_Cal[1] <<16) + (((int64_t)dT * _Cal[3]) >> 7); int64_t sens = ((uint32_t)_Cal[0] <<15) + (((int64_t)dT * _Cal[2]) >> 8); return ((( (rawPress * sens ) >> 21) - off) >> 15) / 100.0; } float MS561101BA::getTemperature(uint8_t OSR) { // see datasheet page 7 for formulas int64_t dT = getDeltaTemp(OSR); if(dT != NULL) { return (2000 + ((dT * _Cal[5]) >> 23)) / 100.0; } else { return NULL; } } int32_t MS561101BA::getDeltaTemp(uint8_t OSR) { uint32_t rawTemp = rawTemperature(OSR); if(rawTemp != NULL) { return (int32_t)(rawTemp - ((uint32_t)_Cal[4] << 8)); } else { return NULL; } } //TODO: avoid duplicated code between rawPressure and rawTemperature methods //TODO: possible race condition between readings.. serious headache doing this.. help appreciated! uint32_t MS561101BA::rawPressure(uint8_t OSR) { uint32_t now = t.read_us(); if(lastPresConv != 0 && (now - lastPresConv) >= CONVERSION_TIME) { lastPresConv = 0; pressCache = getConversion(MS561101BA_D1 + OSR); } else { if(lastPresConv == 0 && lastTempConv == 0) { startConversion(MS561101BA_D1 + OSR); lastPresConv = now; } } return pressCache; } uint32_t MS561101BA::rawTemperature(uint8_t OSR) { unsigned long now = t.read_us(); if(lastTempConv != 0 && (now - lastTempConv) >= CONVERSION_TIME) { lastTempConv = 0; tempCache = getConversion(MS561101BA_D2 + OSR); } else { if(lastTempConv == 0 && lastPresConv == 0) { // no conversions in progress startConversion(MS561101BA_D2 + OSR); lastTempConv = now; } } return tempCache; } // see page 11 of the datasheet void MS561101BA::startConversion(uint8_t command) { // initialize pressure conversion i2c.start(); i2c.write(_addr<<1); i2c.write(command); i2c.stop(); } uint32_t MS561101BA::getConversion(uint8_t command) { uint32_t conversion = 0; // start read sequence /*Wire.beginTransmission(_addr); Wire.write(0); Wire.endTransmission();*/ i2c.start(); i2c.write(_addr<<1); i2c.write(0); i2c.stop(); //Wire.beginTransmission(_addr); //Wire.requestFrom(_addr, (uint8_t) MS561101BA_D1D2_SIZE); char cobuf[3]; if (i2c.read((_addr<<1)+1, cobuf, MS561101BA_D1D2_SIZE)!=0) {conversion=0xFFFFFFFF;}else{ conversion = (cobuf[0] << 16) + (cobuf[1] << 8) + cobuf[2]; } return conversion; } /** * Reads factory calibration and store it into object variables. */ int MS561101BA::readPROM() { for (int i=0;i<MS561101BA_PROM_REG_COUNT;i++) { /*Wire.beginTransmission(_addr); Wire.write(MS561101BA_PROM_BASE_ADDR + (i * MS561101BA_PROM_REG_SIZE)); Wire.endTransmission();*/ i2c.start(); i2c.write(_addr<<1); i2c.write(MS561101BA_PROM_BASE_ADDR + (i * MS561101BA_PROM_REG_SIZE)); i2c.stop(); char tmp[2]; if (i2c.read((_addr<<1)+1, tmp, MS561101BA_PROM_REG_SIZE)!=0) return -1; _Cal[i] = tmp[0]<<8 | tmp[1]; wait_ms(200); } return 0; } /** * Send a reset command to the device. With the reset command the device * populates its internal registers with the values read from the PROM. */ void MS561101BA::reset() { /*Wire.beginTransmission(_addr); Wire.write(MS561101BA_RESET); Wire.endTransmission();*/ i2c.start(); i2c.write(_addr<<1); i2c.write(MS561101BA_RESET); i2c.stop(); }