Tim Marvin / LIS331_lib

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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

LIS331.cpp Show annotated file Show diff for this revision Revisions of this file
LIS331.h Show annotated file Show diff for this revision Revisions of this file 
--- 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: