BMP085_old.cpp

00001 
00002 #include "mbed.h"
00003 #include "BMP085_old.h"
00004 
00005 //I2C Adresse
00006 #define BMP085_ADRESS 0xEE
00007 
00008 #define xpow(x, y) ((long)1 << y)
00009 
00010 
00011 // Constructor
00012 // -----------------------------------------------
00013 BMP085_old::BMP085_old(PinName sda, PinName scl) : i2c_(sda, scl)
00014     {
00015     Init();
00016     // MYINIT -------
00017     oss = 0; //Oversampling des Barometers setzen
00018     // MYINIT -------
00019     }
00020     
00021 
00022 // Temperatur und Druck auslesen und berechnen
00023 // -----------------------------------------------
00024 void BMP085_old::Update () 
00025     {
00026     long P, UTemp, UPressure, X1, X2, X3, B3, B5, B6;
00027     unsigned long B4, B7;
00028 
00029     twi_writechar(BMP085_ADRESS, 0xf4, 0x2e);
00030     // Wait at least 4.5ms
00031     wait(0.005);
00032     UTemp = twi_readshort(BMP085_ADRESS, 0xf6);
00033     
00034     X1 = ((UTemp - AC6) * AC5) >> 15;
00035     X2 = (MC << 11) / (X1 + MD);
00036     B5 = X1 + X2;
00037     Temperature = (float)((B5 + 8) >> 4)/10.0;
00038 
00039     twi_writechar(BMP085_ADRESS, 0xf4, 0x34 + (oss << 6));
00040     // Wait at least 4.5ms
00041     wait(0.005);
00042     UPressure = twi_readlong(BMP085_ADRESS, 0xf6) >> (8 - oss);
00043 
00044     B6 = B5 - 4000;
00045     X1 = (B2 * (B6 * B6) >> 12) >> 11;
00046     X2 = (AC2 * B6) >> 11;
00047     X3 = X1 + X2;
00048     B3 = ((AC1 * 4 + X3) << oss) >> 2;    
00049 
00050     X1 = (AC3 * B6) >> 13;
00051     X2 = (B1 * (B6 * B6) >> 12) >> 16;
00052     X3 = ((X1 + X2) + 2) >> 2;
00053     B4 = AC4 * (X3 + 32768) >> 15;
00054     
00055     B7 = (unsigned long)(UPressure - B3) * (50000 >> oss);
00056     
00057     if (B7 < 0x80000000) 
00058         {
00059         P = (2 * B7) / B4;
00060         }
00061     else 
00062         {
00063         P = 2* (B7 / B4);
00064         }
00065     X1 = (P >> 8) * (P >> 8);
00066     X1 = (X1 * 3038) >> 16;
00067     X2 = (-7357 * P) >> 16;    
00068     P = P + ((X1 + X2 + 3791) >> 4);
00069     Pressure = (float)P / 100.0;
00070     }
00071 
00072 
00073 // Hoehe u.M. berechnen  (Druck in hPa)
00074 // -----------------------------------------------
00075 float BMP085_old::CalcAltitude(float Press)
00076     {
00077     float A = Press/1013.25;
00078     float B = 1/5.25588;
00079     float C = pow(A,B);
00080     
00081     C = 1 - C;
00082     C = C / 22.5577e-6;
00083     return C;
00084     }
00085     
00086         
00087 // Drucksensor initialisieren  
00088 // -----------------------------------------------
00089 void BMP085_old::Init () 
00090     {
00091     AC1 = twi_readshort(BMP085_ADRESS, 0xaa);
00092     AC2 = twi_readshort(BMP085_ADRESS, 0xac);
00093     AC3 = twi_readshort(BMP085_ADRESS, 0xae);
00094     AC4 = twi_readshort(BMP085_ADRESS, 0xb0);
00095     AC5 = twi_readshort(BMP085_ADRESS, 0xb2);
00096     AC6 = twi_readshort(BMP085_ADRESS, 0xb4);
00097     B1 = twi_readshort(BMP085_ADRESS, 0xb6);
00098     B2 = twi_readshort(BMP085_ADRESS, 0xb8);
00099     MB = twi_readshort(BMP085_ADRESS, 0xba);
00100     MC = twi_readshort(BMP085_ADRESS, 0xbc);
00101     MD = twi_readshort(BMP085_ADRESS, 0xbe);
00102     }
00103     
00104     
00105 // -----------------------------------------------
00106 unsigned short BMP085_old::twi_readshort (int id, int addr) {
00107     unsigned short i;
00108 
00109     i2c_.start();
00110     i2c_.write(id);
00111     i2c_.write(addr);
00112 
00113     i2c_.start();
00114     i2c_.write(id | 1);
00115     i = i2c_.read(1) << 8;
00116     i |= i2c_.read(0);
00117     i2c_.stop();
00118 
00119     return i;
00120 }
00121 
00122 
00123 // -----------------------------------------------
00124 unsigned long BMP085_old::twi_readlong (int id, int addr) {
00125     unsigned long i;
00126 
00127     i2c_.start();
00128     i2c_.write(id);
00129     i2c_.write(addr);
00130 
00131     i2c_.start();
00132     i2c_.write(id | 1);
00133     i = i2c_.read(1) << 16;
00134     i |= i2c_.read(1) << 8;
00135     i |= i2c_.read(0);
00136     i2c_.stop();
00137 
00138     return i;
00139 }
00140 
00141 
00142 // -----------------------------------------------
00143 void BMP085_old::twi_writechar (int id, int addr, int dat) {
00144 
00145     i2c_.start();
00146     i2c_.write(id);
00147     i2c_.write(addr);
00148     i2c_.write(dat);
00149     i2c_.stop();
00150 }