Revision 3:0e92710a46f9, committed 2015-03-14

Comitter:

eencae

Date:

Sat Mar 14 12:57:44 2015 +0000

Parent:

2:79d0d565c3af

Commit message:

Added DEBUG mode to check algorithm and compare to data sheet value.; Uncomment #define DEBUG in header file.; Confirmed agreement with data sheet values.

Changed in this revision

diff -r 79d0d565c3af -r 0e92710a46f9 BMP180.cpp
--- a/BMP180.cpp	Fri Mar 13 18:44:57 2015 +0000
+++ b/BMP180.cpp	Sat Mar 14 12:57:44 2015 +0000
@@ -39,9 +39,11 @@
     char MSB = readByteFromRegister(0xF6);
     char LSB = readByteFromRegister(0xF7);
     // combine in 16-bit value
-    int UT = (MSB << 8) | LSB;   
-    //int32_t UT = 27898;  // test data from datasheet
-    //printf("\n\nUT = %d\n",UT);
+    int UT = (MSB << 8) | LSB;
+#ifdef DEBUG
+    UT = 27898;  // test data from datasheet
+    printf("****DEBUG MODE****\nUT = %d\n",UT);
+#endif
     return UT;
 }
 
@@ -55,12 +57,12 @@
     char MSB = readByteFromRegister(0xF6);
     char LSB = readByteFromRegister(0xF7);
     char XLSB = readByteFromRegister(0xF7);
-    // just do 16-bit, not 19-bit
-    //int UP = (MSB << 16 | LSB << 8 | XLSB) >> (8 - oss);
-    int UP = (MSB << 16 | LSB << 8) >> (8 - oss);
-    
-    //int32_t UP = 23843;   // test data from datasheet
-    //printf("UP = %d\n",UP);
+    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;
 }
 
@@ -71,7 +73,9 @@
     X2 = (calibration.MC << 11) / (X1 + calibration.MD);
     B5 = X1 + X2;
     int32_t T = (B5 + 8) >> 4;
-    //printf("X1=%d\nX2=%d\nB5=%d\n*****\nT=%d\n******\n",X1,X2,B5,T);
+#ifdef DEBUG
+    printf("****\nX1=%d\nX2=%d\nB5=%d\nT=%d\n",X1,X2,B5,T);
+#endif
     return T;
 }
 
@@ -79,34 +83,49 @@
 {
     // equations from data sheet
     B6 = B5 - 4000;
-    //printf("\n********\nB6=%d\n",B6);
     X1 = (calibration.B2 * ((B6*B6) >> 12))>>11;
     X2 = (calibration.AC2*B6)>>11;
     X3 = X1 + X2;
     B3 = (((calibration.AC1*4 + X3) << oss)+2)/4;
-    //printf("X1=%d\nX2=%d\nX3=%d\nB3=%d\n",X1,X2,X3,B3);
+#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;
-    //printf("X1=%d\nX2=%d\nX3=%d\nB4=%u\n",X1,X2,X3,B4);
+#ifdef DEBUG
+    printf("X1=%d\nX2=%d\nX3=%d\nB4=%u\n",X1,X2,X3,B4);
+#endif
     B7 = ((uint32_t)UP - B3)*(50000>>oss);
-    //printf("B7=%u\n",B7);
+#ifdef DEBUG
+    printf("B7=%u\n",B7);
+#endif
     int32_t P;
     if (B7 < 0x80000000)
         P = (B7*2)/B4;
     else
         P = (B7/B4)*2;
-    //printf("P=%d\n",P);
+#ifdef DEBUG
+    printf("P=%d\n",P);
+#endif
     X1 = (P>>8)*(P>>8);
-    //printf("X1=%d\n",X1);
+#ifdef DEBUG
+    printf("X1=%d\n",X1);
+#endif
     X1 = (X1*3038)>>16;
-    //printf("X1=%d\n",X1);
+#ifdef DEBUG
+    printf("X1=%d\n",X1);
+#endif
     X2 = (-7357*P)>>16;
-    //printf("X2=%d\n",X2);
+#ifdef DEBUG
+    printf("X2=%d\n",X2);
+#endif
     P = P + (X1+X2+3791)/16;
-    //printf("P=%d\n",P);
-    
+#ifdef DEBUG
+    printf("P=%d\n",P);
+#endif
+
     return P;
 
 }
@@ -120,17 +139,22 @@
     if (data != 0x55) { // if correct ID not found, hang and flash error message
         error();
     }
-    
+
     readCalibrationData();
+
     oss = 1;  // standard power oversampling setting
-    //oss = 0;  // used when testing data sheet example
+
+#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);
@@ -146,13 +170,25 @@
     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
-    //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("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);
+#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
 }
 
 

diff -r 79d0d565c3af -r 0e92710a46f9 BMP180.h
--- a/BMP180.h	Fri Mar 13 18:44:57 2015 +0000
+++ b/BMP180.h	Sat Mar 14 12:57:44 2015 +0000
@@ -15,6 +15,9 @@
 #define ID_REG          0xD0
 #define EEPROM_REG_ADD  0xAA
 
+// uncomment line below to run in debug mode and compare to datasheet values
+//#define DEBUG
+
 // Struct to store calibration data
 typedef struct Calibration Calibration;
 struct Calibration {