Revision 10:dcd11c84305e, committed 2014-06-17

Comitter:

atommota

Date:

Tue Jun 17 21:40:59 2014 +0000

Parent:

9:5af73355984f

Commit message:

Fixed bug in last release where getAccelZ was being cast to an int instead of a float. Changed the set range functions to preserve the contents of the CTRL_REG_4 register. Additionally, those functions now return the value written to the register.

Changed in this revision

--- a/LIS331.cpp	Tue Jun 17 19:31:05 2014 +0000
+++ b/LIS331.cpp	Tue Jun 17 21:40:59 2014 +0000
@@ -111,40 +111,75 @@
 }
 
 
-void LIS331::setFullScaleRange8g(void){  // Does not preserve rest of CTRL_REG_4!
+char LIS331::setFullScaleRange8g(void){ 
+    // Set our scaling factor and G range variables
     scaling_factor = 4096.0;
     current_range = 8;
-    char tx[2];
-    tx[0] = CTRL_REG_4;
-    tx[1] = 0x30;
+    
+    // Setup our tx and rx arrays
+    char tx1;
+    char tx2[2];
+    char rx;
     
-    i2c_.write((LIS331_I2C_ADDRESS << 1) & 0xFE, tx, 2);
+    // Need to read current register value so we can preserve it
+    // Set our device register address to Control Register 4 and read its contents
+    tx1 = CTRL_REG_4;
+    i2c_.write((LIS331_I2C_ADDRESS << 1) & 0xFE, &tx1, 1);
+    i2c_.read((LIS331_I2C_ADDRESS << 1) | 0x01, &rx, 1);
     
+    tx2[0] = CTRL_REG_4;
+    rx |= 1 << 5;    // set 6th bit
+    rx |= 1 << 4;    // set 5th bit
+    tx2[1] = rx;  
+    
+    i2c_.write((LIS331_I2C_ADDRESS << 1) & 0xFE, tx2, 2);
+    return rx;
 }
 
-void LIS331::setFullScaleRange4g(void){  // Does not preserve rest of CTRL_REG_4!
+char LIS331::setFullScaleRange4g(void){  
     scaling_factor = 8192.0;
     current_range = 4;
     
-    char tx[2];
-    tx[0] = CTRL_REG_4;
-    tx[1] = 0x10;
+    char tx1; 
+    char tx2[2];
+    char rx;
+    
+    // Need to read current register value so we can preserve it
+    // Set our device register address to Control Register 4 and read its contents
+    tx1 = CTRL_REG_4;
+    i2c_.write((LIS331_I2C_ADDRESS << 1) & 0xFE, &tx1, 1);
+    i2c_.read((LIS331_I2C_ADDRESS << 1) | 0x01, &rx, 1);
+    tx2[0] = CTRL_REG_4;
+    rx &= ~(1 << 5);    // Clear 6th bit
+    rx |= 1 << 4;       // set 5th bit
+    tx2[1] = rx;  
         
-    i2c_.write((LIS331_I2C_ADDRESS << 1) & 0xFE, tx, 2);
-    
+    i2c_.write((LIS331_I2C_ADDRESS << 1) & 0xFE, tx2, 2);
+    return rx;
 }
     
 
-void LIS331::setFullScaleRange2g(void){  // Does not preserve rest of CTRL_REG_4!
+char LIS331::setFullScaleRange2g(void){  
     scaling_factor = 16384.0;
     current_range = 2;
     
-    char tx[2];
-    tx[0] = CTRL_REG_4;
-    tx[1] = 0x00;
+    char tx1;
+    char tx2[2];
+    char rx;
+    
+    // Need to read current register value so we can preserve it
+    // Set our device register address to Control Register 4 and read its contents
+    tx1 = CTRL_REG_4;
+    i2c_.write((LIS331_I2C_ADDRESS << 1) & 0xFE, &tx1, 1);
+    i2c_.read((LIS331_I2C_ADDRESS << 1) | 0x01, &rx, 1);
+    
+    tx2[0] = CTRL_REG_4;
+    rx &= ~(1 << 5);    // Clear 6th bit
+    rx &= ~(1 << 4);    // clear 5th bit
+    tx2[1] = rx;  
         
-    i2c_.write((LIS331_I2C_ADDRESS << 1) & 0xFE, tx, 2);
-    
+    i2c_.write((LIS331_I2C_ADDRESS << 1) & 0xFE, tx2, 2);
+    return rx;
 }
 
 
@@ -171,7 +206,7 @@
     
     i2c_.read((LIS331_I2C_ADDRESS << 1) | 0x01, rx, 2);
     
-    int16_t output = ((int) rx[0] << 8) | ((int) rx[1]);
+    int16_t output = ((int) rx[1] << 8) | ((int) rx[0]);
 
     return output/scaling_factor;
 
@@ -186,13 +221,13 @@
     
     i2c_.read((LIS331_I2C_ADDRESS << 1) | 0x01, rx, 2);
     
-    int16_t output = ((int) rx[0] << 8) | ((int) rx[1]);
+    int16_t output = ((int) rx[1] << 8) | ((int) rx[0]);
 
     return output/scaling_factor;
 
 }
 
-int LIS331::getAccelZ(void){
+float LIS331::getAccelZ(void){
 
     char tx = ACCEL_ZOUT_L_REG | 0x80;
     char rx[2];
@@ -201,7 +236,7 @@
     
     i2c_.read((LIS331_I2C_ADDRESS << 1) | 0x01, rx, 2);
     
-    int16_t output = ((int) rx[0] << 8) | ((int) rx[1]);
+    int16_t output = ((int) rx[1] << 8) | ((int) rx[0]);
 
     return output/scaling_factor;
 

--- a/LIS331.h	Tue Jun 17 19:31:05 2014 +0000
+++ b/LIS331.h	Tue Jun 17 21:40:59 2014 +0000
@@ -36,8 +36,6 @@
 #define ACCEL_ZOUT_H_REG 0x2D
 #define ACCEL_ZOUT_L_REG 0x2C
 
-
-
 #define CTRL_REG_1      0x20
 #define CTRL_REG_2      0x21
 #define CTRL_REG_3      0x22
@@ -168,21 +166,21 @@
   
     /**
      * Set the Full Scale Range to +/- 8g's.
-     *
+     * Returns the value written to CTRL_REG_4
      */     
-    void setFullScaleRange8g(void);
+    char setFullScaleRange8g(void);
 
     /**
      * Set the Full Scale Range to +/- 4g's.
-     *
+     * Returns the value written to CTRL_REG_4
      */     
-    void setFullScaleRange4g(void);
+    char setFullScaleRange4g(void);
 
     /**
      * Set the Full Scale Range to +/- 2g's.
-     *
+     * Returns the value written to CTRL_REG_4
      */     
-    void setFullScaleRange2g(void);
+    char setFullScaleRange2g(void);
      
             
     char getAccelStatus(void);
@@ -209,7 +207,7 @@
      * 
      * @return The output on the z-axis in engineering units (g's).
      */
-    int getAccelZ(void);
+    float getAccelZ(void);
 
    
 private: