Diff: Sensors/Acc/ADXL345.cpp

Revision:

17:e096e85f6c36

Parent:

15:753c5d6a63b3

Child:

18:c8c09a3913ba

--- a/Sensors/Acc/ADXL345.cpp	Wed Oct 31 14:44:07 2012 +0000
+++ b/Sensors/Acc/ADXL345.cpp	Wed Oct 31 16:53:01 2012 +0000
@@ -1,91 +1,47 @@
 #include "ADXL345.h"
-#include "mbed.h"
-
-ADXL345::ADXL345(PinName sda, PinName scl) : i2c(sda, scl) {
 
-    //400kHz, allowing us to use the fastest data rates.
-    //there are other chips on board, sorry
-    i2c.frequency(400000);   
+ADXL345::ADXL345(PinName sda, PinName scl) : I2C_Sensor(sda, scl, ADXL345_I2C_ADDRESS)
+{
     // initialize the BW data rate
-    char tx[2];
-    tx[0] = ADXL345_BW_RATE_REG;
-    tx[1] = ADXL345_1600HZ; //value greater than or equal to 0x0A is written into the rate bits (Bit D3 through Bit D0) in the BW_RATE register 
-    i2c.write( ADXL345_WRITE , tx, 2);  
+    writeRegister(ADXL345_BW_RATE_REG, ADXL345_1600HZ); //value greater than or equal to 0x0A is written into the rate bits (Bit D3 through Bit D0) in the BW_RATE register
 
     //Data format (for +-16g) - This is done by setting Bit D3 of the DATA_FORMAT register (Address 0x31) and writing a value of 0x03 to the range bits (Bit D1 and Bit D0) of the DATA_FORMAT register (Address 0x31).
-   
- char rx[2];
-    rx[0] = ADXL345_DATA_FORMAT_REG;
-    rx[1] = 0x0B; 
-     // full res and +_16g
- i2c.write( ADXL345_WRITE , rx, 2); 
+    writeRegister(ADXL345_DATA_FORMAT_REG, 0x0B);       // full res and +_16g
  
     // Set Offset  - programmed into the OFSX, OFSY, and OFXZ registers, respectively, as 0xFD, 0x03 and 0xFE.
-  char x[2];
-    x[0] = ADXL345_OFSX_REG ;
-    //x[1] = 0xFD; 
-    x[1] = 0x00; 
- i2c.write( ADXL345_WRITE , x, 2);
-  char y[2];
-    y[0] = ADXL345_OFSY_REG ;
-    //y[1] = 0x03;
-    y[1] = 0x00; 
- i2c.write( ADXL345_WRITE , y, 2);
- char z[2];
-    z[0] = ADXL345_OFSZ_REG ;
-    //z[1] = 0xFE;
-    z[1] = 0x00;
- i2c.write( ADXL345_WRITE , z, 2);
+    writeRegister(ADXL345_OFSX_REG, 0x00);              // TODO: 0xFD (sein offset! brauch ich auch?)
+    writeRegister(ADXL345_OFSY_REG, 0x00);              // y[1] = 0x03;
+    writeRegister(ADXL345_OFSZ_REG, 0x00);              // z[1] = 0xFE;
  
- // MY INITIALISATION -------------------------------------------------------
- 
-    writeReg(ADXL345_POWER_CTL_REG, 0x00); // set power control
-    writeReg(ADXL345_DATA_FORMAT_REG, 0x0B); // set data format
-    setDataRate(ADXL345_3200HZ); // set data rate
-    writeReg(ADXL345_POWER_CTL_REG, 0x08); // set mode
+    writeRegister(ADXL345_POWER_CTL_REG, 0x00);         // set power control
+    writeRegister(ADXL345_DATA_FORMAT_REG, 0x0B);       // set data format
+    setDataRate(ADXL345_3200HZ);                        // set data rate
+    writeRegister(ADXL345_POWER_CTL_REG, 0x08);         // set mode
 }
 
-void ADXL345::read(){
-    char buffer[6];    
-    readMultiReg(ADXL345_DATAX0_REG, buffer, 6);
+void ADXL345::read()
+{
+    char buffer[6];                                     // 8-Bit pieces of axis data
     
-    data[0] = (short) ((int)buffer[1] << 8 | (int)buffer[0]);
-    data[1] = (short) ((int)buffer[3] << 8 | (int)buffer[2]);
-    data[2] = (short) ((int)buffer[5] << 8 | (int)buffer[4]);
+    readMultiRegister(ADXL345_DATAX0_REG, buffer, 6);   // read axis registers using I2C
+    
+    data[0] = (short) (buffer[1] << 8 | buffer[0]);     // join 8-Bit pieces to 16-bit short integers
+    data[1] = (short) (buffer[3] << 8 | buffer[2]);
+    data[2] = (short) (buffer[5] << 8 | buffer[4]);
     
     // calculate the angles for roll and pitch (0,1)
-    float R = sqrt(pow((float)data[0],2) + pow((float)data[1],2) + pow((float)data[2],2));
-    angle[0] = -(Rad2Deg * acos((float)data[1] / R)-90);
-    angle[1] =   Rad2Deg * acos((float)data[0] / R)-90;
-    angle[2] =   Rad2Deg * acos((float)data[2] / R);
+    float R = sqrt(pow((float)data[0],2) + pow((float)data[1],2) + pow((float)data[2],2));  // calculate the absolute of the magnetic field vector
+    angle[0] = -(RAD2DEG * acos((float)data[1] / R)-90);                                    // roll - angle of magnetic field vector in x direction
+    angle[1] =   RAD2DEG * acos((float)data[0] / R)-90;                                    // pitch - angle of magnetic field vector in y direction
+    angle[2] =   RAD2DEG * acos((float)data[2] / R);                                        // angle from magnetic field vector in direction which it has
 }
 
-void ADXL345::writeReg(char address, char data){ 
-   char tx[2];
-   tx[0] = address;
-   tx[1] = data;
-   i2c.write(ADXL345_WRITE, tx, 2);
-}
-
-char ADXL345::readReg(char address){   
-   char tx = address;
-   char output; 
-    i2c.write( ADXL345_WRITE , &tx, 1);  //tell it what you want to read
-    i2c.read( ADXL345_READ , &output, 1);    //tell it where to store the data
-    return output; 
-}
-
-void ADXL345::readMultiReg(char address, char* output, int size) {
-    i2c.write(ADXL345_WRITE, &address, 1, true); //tell it where to read from
-    i2c.read(ADXL345_READ , output, size, true); //tell it where to store the data read
-}
-
-void ADXL345::setDataRate(char rate) {
-    //Get the current register contents, so we don't clobber the power bit.
-    char registerContents = readReg(ADXL345_BW_RATE_REG);
+void ADXL345::setDataRate(char rate)
+{
+    char registerContents = readRegister(ADXL345_BW_RATE_REG); // get the current register contents, so we don't clobber the power bit
 
     registerContents &= 0x10;
     registerContents |= rate;
 
-    writeReg(ADXL345_BW_RATE_REG, registerContents);
+    writeRegister(ADXL345_BW_RATE_REG, registerContents);
 }
\ No newline at end of file