Revision 4:1eec283ff5e7, committed 2015-05-07

Comitter:

qk2277

Date:

Thu May 07 16:13:12 2015 +0000

Parent:

3:0e92710a46f9

Commit message:

the first version of my project

Changed in this revision

diff -r 0e92710a46f9 -r 1eec283ff5e7 BMP180.cpp
--- a/BMP180.cpp	Sat Mar 14 12:57:44 2015 +0000
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,245 +0,0 @@
-/**
-@file BMP180.cpp
-
-@brief Member functions implementations
-
-*/
-#include "mbed.h"
-#include "BMP180.h"
-
-BMP180::BMP180(PinName sdaPin, PinName sclPin)
-{
-    i2c = new I2C(sdaPin,sclPin); // create new I2C instance and initialise
-    i2c->frequency(400000);       // I2C Fast Mode - 400kHz
-    leds = new BusOut(LED4,LED3,LED2,LED1);
-}
-
-Measurement BMP180::readValues()
-{
-    // algorithm for taking measurement is taken from datasheet
-    int32_t UT = readUncompensatedTemperatureValue();
-    int32_t UP = readUncompensatedPressureValue();
-    // once you have the uncompensated T and P, you can calculate the true T and P
-    // using the equations from the datasheet
-    int32_t T = calcTrueTemperature(UT);
-    int32_t P = calcTruePressure(UP);
-
-    Measurement measurement;
-    measurement.temperature = T*0.1;  // scaled by 0.1 C
-    measurement.pressure = P*0.01;    // Put pressure in mb
-
-    return measurement;
-}
-
-int32_t BMP180::readUncompensatedTemperatureValue()
-{
-    // from algorithm in datasheet - p15
-    sendByteToRegister(0x2E,0xF4);
-    wait_ms(5);  // 4.5 ms delay for OSS = 1
-    char MSB = readByteFromRegister(0xF6);
-    char LSB = readByteFromRegister(0xF7);
-    // combine in 16-bit value
-    int UT = (MSB << 8) | LSB;
-#ifdef DEBUG
-    UT = 27898;  // test data from datasheet
-    printf("****DEBUG MODE****\nUT = %d\n",UT);
-#endif
-    return UT;
-}
-
-int32_t BMP180::readUncompensatedPressureValue()
-{
-    // from datasheet
-    char byte = 0x34 + (oss << 6);
-    sendByteToRegister(byte,0xF4);
-    wait_ms(8);  // 7.5 ms delay for OSS = 1
-
-    char MSB = readByteFromRegister(0xF6);
-    char LSB = readByteFromRegister(0xF7);
-    char XLSB = readByteFromRegister(0xF7);
-    int UP = (MSB << 16 | LSB << 8 | XLSB) >> (8 - oss);
-
-#ifdef DEBUG
-    UP = 23843;   // test data from datasheet
-    printf("UP = %d\n",UP);
-#endif
-    return UP;
-}
-
-int32_t BMP180::calcTrueTemperature(int32_t UT)
-{
-    // equations from data sheet
-    X1 = ((UT - calibration.AC6)*calibration.AC5) >> 15;
-    X2 = (calibration.MC << 11) / (X1 + calibration.MD);
-    B5 = X1 + X2;
-    int32_t T = (B5 + 8) >> 4;
-#ifdef DEBUG
-    printf("****\nX1=%d\nX2=%d\nB5=%d\nT=%d\n",X1,X2,B5,T);
-#endif
-    return T;
-}
-
-int32_t BMP180::calcTruePressure(int32_t UP)
-{
-    // equations from data sheet
-    B6 = B5 - 4000;
-    X1 = (calibration.B2 * ((B6*B6) >> 12))>>11;
-    X2 = (calibration.AC2*B6)>>11;
-    X3 = X1 + X2;
-    B3 = (((calibration.AC1*4 + X3) << oss)+2)/4;
-#ifdef DEBUG
-    printf("*****\nB6=%d\nX1=%d\nX2=%d\nX3=%d\nB3=%d\n",B6,X1,X2,X3,B3);
-#endif
-    X1 = (calibration.AC3*B6)>>13;
-    X2 = (calibration.B1*((B6*B6)>>12))>>16;
-    X3 = ((X1+X2)+2)/4;
-    B4 = (calibration.AC4*(uint32_t)(X3+32768))>>15;
-#ifdef DEBUG
-    printf("X1=%d\nX2=%d\nX3=%d\nB4=%u\n",X1,X2,X3,B4);
-#endif
-    B7 = ((uint32_t)UP - B3)*(50000>>oss);
-#ifdef DEBUG
-    printf("B7=%u\n",B7);
-#endif
-    int32_t P;
-    if (B7 < 0x80000000)
-        P = (B7*2)/B4;
-    else
-        P = (B7/B4)*2;
-#ifdef DEBUG
-    printf("P=%d\n",P);
-#endif
-    X1 = (P>>8)*(P>>8);
-#ifdef DEBUG
-    printf("X1=%d\n",X1);
-#endif
-    X1 = (X1*3038)>>16;
-#ifdef DEBUG
-    printf("X1=%d\n",X1);
-#endif
-    X2 = (-7357*P)>>16;
-#ifdef DEBUG
-    printf("X2=%d\n",X2);
-#endif
-    P = P + (X1+X2+3791)/16;
-#ifdef DEBUG
-    printf("P=%d\n",P);
-#endif
-
-    return P;
-
-}
-
-// configure the barometer
-void BMP180::init()
-{
-    i2c->frequency(400000); // set Fast Mode I2C frequency
-
-    char data = readByteFromRegister(ID_REG);  // Section 4 - datasheet
-    if (data != 0x55) { // if correct ID not found, hang and flash error message
-        error();
-    }
-
-    readCalibrationData();
-
-    oss = 1;  // standard power oversampling setting
-
-#ifdef DEBUG
-    oss = 0;  // used when testing data sheet example
-#endif
-
-
-}
-
-// Reads factory calibrated data
-void BMP180::readCalibrationData()
-{
-
-    char eeprom[22];
-
-    readBytesFromRegister(EEPROM_REG_ADD,22,eeprom);
-    // store calibration data in structure
-    calibration.AC1 = (int16_t) (eeprom[0] << 8) | eeprom[1];
-    calibration.AC2 = (int16_t) (eeprom[2] << 8) | eeprom[3];
-    calibration.AC3 = (int16_t) (eeprom[4] << 8) | eeprom[5];
-    calibration.AC4 = (uint16_t) (eeprom[6] << 8) | eeprom[7];
-    calibration.AC5 = (uint16_t) (eeprom[8] << 8) | eeprom[9];
-    calibration.AC6 = (uint16_t) (eeprom[10] << 8) | eeprom[11];
-    calibration.B1 = (int16_t) (eeprom[12] << 8) | eeprom[13];
-    calibration.B2 = (int16_t) (eeprom[14] << 8) | eeprom[15];
-    calibration.MB = (int16_t) (eeprom[16] << 8) | eeprom[17];
-    calibration.MC = (int16_t) (eeprom[18] << 8) | eeprom[19];
-    calibration.MD = (int16_t) (eeprom[20] << 8) | eeprom[21];
-
-    // test data from data sheet
-#ifdef DEBUG
-    calibration.AC1 = 408;
-    calibration.AC2 = -72;
-    calibration.AC3 = -14383;
-    calibration.AC4 = 32741;
-    calibration.AC5 = 32757;
-    calibration.AC6 = 23153;
-    calibration.B1 = 6190;
-    calibration.B2 = 4;
-    calibration.MB = -32768;
-    calibration.MC = -8711;
-    calibration.MD = 2868;
-    printf("****EXAMPLE CALIBRATION DATA****\n");
-    printf("AC1=%d\nAC2=%d\nAC3=%d\nAC4=%u\nAC5=%u\nAC6=%u\nB1=%d\nB2=%d\nMB=%d\nMC=%d\nMD=%d\n",
-           calibration.AC1,calibration.AC2,calibration.AC3,calibration.AC4,calibration.AC5,calibration.AC6,
-           calibration.B1,calibration.B2,calibration.MB,calibration.MC,calibration.MD);
-#endif
-}
-
-
-// reads a byte from a specific register
-char BMP180::readByteFromRegister(char reg)
-{
-    int nack = i2c->write(BMP180_W_ADDRESS,&reg,1,true);  // send the register address to the slave
-    if (nack)
-        error();  // if we don't receive acknowledgement, flash error message
-
-    char rx;
-    nack = i2c->read(BMP180_W_ADDRESS,&rx,1);  // read a byte from the register and store in buffer
-    if (nack)
-        error();  // if we don't receive acknowledgement, flash error message
-
-    return rx;
-}
-
-// reads a series of bytes, starting from a specific register
-void BMP180::readBytesFromRegister(char reg,int numberOfBytes,char bytes[])
-{
-    int nack = i2c->write(BMP180_W_ADDRESS,&reg,1,true);  // send the slave write address and the configuration register address
-
-    if (nack)
-        error();  // if we don't receive acknowledgement, flash error message
-
-    nack = i2c->read(BMP180_W_ADDRESS,bytes,numberOfBytes);  // read bytes
-    if (nack)
-        error();  // if we don't receive acknowledgement, flash error message
-
-}
-
-// sends a byte to a specific register
-void BMP180::sendByteToRegister(char byte,char reg)
-{
-    char data[2];
-    data[0] = reg;
-    data[1] = byte;
-    // send the register address, followed by the data
-    int nack = i2c->write(BMP180_W_ADDRESS,data,2);
-    if (nack)
-        error();  // if we don't receive acknowledgement, flash error message
-
-}
-
-void BMP180::error()
-{
-    while(1) {
-        leds->write(15);
-        wait(0.1);
-        leds->write(0);
-        wait(0.1);
-    }
-}
\ No newline at end of file