Adafruit_MPL3115A2.cpp

/**************************************************************************/
/*!
    EDITED FOR ES2A8 PROJECT - ROCKET INSTRUMENTATION - GROUP C
　
@file Adafruit_MPL3115A2.cpp
@author K.Townsend (Adafruit Industries)
@license BSD (see license.txt)
Driver for the MPL3115A2 barometric pressure sensor
This is a library for the Adafruit MPL3115A2 breakout
----> https://www.adafruit.com/products/1893
Adafruit invests time and resources providing this open source code,
please support Adafruit and open-source hardware by purchasing
products from Adafruit!
@section HISTORY
v1.0 - First release
*/
/**************************************************************************/
#if ARDUINO >= 100
#include "Arduino.h"
#else
#include "WProgram.h"
#endif
#ifdef __AVR_ATtiny85__
#include <TinyWireM.h>
#define Wire TinyWireM
#else
#include <Wire.h>
#endif
#include "Adafruit_MPL3115A2.h"
/**************************************************************************/
/*!
@brief Instantiates a new MPL3115A2 class
*/
/**************************************************************************/
Adafruit_MPL3115A2::Adafruit_MPL3115A2() {
}
/**************************************************************************/
/*!
@brief Setups the HW (reads coefficients values, etc.)
*/
/**************************************************************************/
boolean Adafruit_MPL3115A2::begin() {
    Wire.begin();
    uint8_t whoami = read8(MPL3115A2_WHOAMI);
    if (whoami != 0xC4) {
        return false;
    }
    write8(MPL3115A2_CTRL_REG1,
        MPL3115A2_CTRL_REG1_OST);
    write8(MPL3115A2_PT_DATA_CFG,
        MPL3115A2_PT_DATA_CFG_TDEFE |
        MPL3115A2_PT_DATA_CFG_PDEFE |
        MPL3115A2_PT_DATA_CFG_DREM);
    return true;
}
/**************************************************************************/
/*!
@brief Gets the floating-point pressure level in kPa
*/
/**************************************************************************/
float Adafruit_MPL3115A2::getPressure(int OverSample) {
    uint32_t pressure;
    write8(MPL3115A2_CTRL_REG1,
        MPL3115A2_CTRL_REG1_OST | OverSample);
    uint8_t sta = 0;
    while (!(sta & MPL3115A2_REGISTER_STATUS_PDR)) {
        sta = read8(MPL3115A2_REGISTER_STATUS);
        delay(10);
    }
    Wire.beginTransmission(MPL3115A2_ADDRESS); // start transmission to device
    Wire.write(MPL3115A2_REGISTER_PRESSURE_MSB);
    Wire.endTransmission(false); // end transmission
    Wire.requestFrom((uint8_t)MPL3115A2_ADDRESS, (uint8_t)3);// send data n-bytes read
    pressure = Wire.read(); // receive DATA
    pressure <<= 8;
    pressure |= Wire.read(); // receive DATA
    pressure <<= 8;
    pressure |= Wire.read(); // receive DATA
    pressure >>= 4;
    float baro = pressure;
    baro /= 4.0;
    return baro;
}

float Adafruit_MPL3115A2::getAltitude(int OverSample) {
    int32_t alt;
    write8(MPL3115A2_CTRL_REG1,
        MPL3115A2_CTRL_REG1_OST | MPL3115A2_CTRL_REG1_ALT | OverSample);
    uint8_t sta = 0;
    while (!(sta & MPL3115A2_REGISTER_STATUS_PDR)) {
        sta = read8(MPL3115A2_REGISTER_STATUS);
        delay(10);
    }
    Wire.beginTransmission(MPL3115A2_ADDRESS); // start transmission to device
    Wire.write(MPL3115A2_REGISTER_PRESSURE_MSB);
    Wire.endTransmission(false); // end transmission
    Wire.requestFrom((uint8_t)MPL3115A2_ADDRESS, (uint8_t)3);// send data n-bytes read
    alt = Wire.read(); // receive DATA
    alt <<= 8;
    alt |= Wire.read(); // receive DATA
    alt <<= 8;
    alt |= Wire.read(); // receive DATA
    alt >>= 4;
    if (alt & 0x80000) {
        alt |= 0xFFF00000;
    }
    float altitude = alt;
    altitude /= 16.0;
    return altitude;
}

/**************************************************************************/
/*!
@brief Gets the floating-point temperature in Centigrade
*/
/**************************************************************************/
float Adafruit_MPL3115A2::getTemperature(int OverSample) {
    int16_t t;
    write8(MPL3115A2_CTRL_REG1,
        MPL3115A2_CTRL_REG1_OST | OverSample);
    uint8_t sta = 0;
    while (!(sta & MPL3115A2_REGISTER_STATUS_TDR)) {
        sta = read8(MPL3115A2_REGISTER_STATUS);
        delay(10);
    }
    Wire.beginTransmission(MPL3115A2_ADDRESS); // start transmission to device
    Wire.write(MPL3115A2_REGISTER_TEMP_MSB);
    Wire.endTransmission(false); // end transmission
    Wire.requestFrom((uint8_t)MPL3115A2_ADDRESS, (uint8_t)2);// send data n-bytes read
    t = Wire.read(); // receive DATA
    t <<= 8;
    t |= Wire.read(); // receive DATA
    t >>= 4;
    float temp = t;
    temp /= 16.0;
    return temp;
}
　　　
/*********************************************************************/
uint8_t Adafruit_MPL3115A2::read8(uint8_t a) {
    Wire.beginTransmission(MPL3115A2_ADDRESS); // start transmission to device
    Wire.write(a); // sends register address to read from
    Wire.endTransmission(false); // end transmission
    Wire.requestFrom((uint8_t)MPL3115A2_ADDRESS, (uint8_t)1);// send data n-bytes read
    return Wire.read(); // receive DATA
}

void Adafruit_MPL3115A2::write8(uint8_t a, uint8_t d) {
    Wire.beginTransmission(MPL3115A2_ADDRESS); // start transmission to device
    Wire.write(a); // sends register address to write to
    Wire.write(d); // sends register data
    Wire.endTransmission(false); // end transmission
}