Revision 1:ef026bf28798, committed 2013-10-08

Comitter:

nherriot

Date:

Tue Oct 08 15:25:32 2013 +0000

Parent:

0:bcf2aa85d7f9

Child:

2:66db0f91b215

Commit message:

adding device id method detection

Changed in this revision

--- a/MMA8452.cpp	Fri Oct 04 14:48:02 2013 +0000
+++ b/MMA8452.cpp	Tue Oct 08 15:25:32 2013 +0000
@@ -27,7 +27,7 @@
 
 
 // Connect module at I2C address using I2C port pins sda and scl
-Accelerometer_MMA8452::Accelerometer_MMA8452(PinName sda, PinName scl,int frequency) : m_i2c(sda, scl): m_frequency(frequency):
+Accelerometer_MMA8452::Accelerometer_MMA8452(PinName sda, PinName scl,int frequency) : m_i2c(sda, scl) , m_frequency(frequency)
 {
     //m_i2c.frequency(m_frequency);
 }
@@ -42,19 +42,21 @@
 // Setting the control register bit 1 to true to activate the MMA8452
 int Accelerometer_MMA8452::activate()
 {
-    char mcu_address = (MMA8452_ADDRESS <1);
+    char mcu_address = (MMA8452_ADDRESS<<1);
     char init[2];
     init[0] = CTRL_REG_1;                 // control register 1
     init[1] = 0x01;                       // set to active
+    //while(m_i2c.write(mcu_address,init,2));
+    
     if(m_i2c.write(mcu_address,init,2) == 0)
     {
          // pc.printf("The initialisation worked");
-         return 0;
+         return 0;  // return 0 to indicate success
     }
     else
     {
         // pc.printf("The initialisation failed");
-        return 1;
+        return 1;   // crumbs it failed!!!
     }
          
 }
@@ -71,6 +73,44 @@
 }
 
 
+// Get device ID 
+int Accelerometer_MMA8452::Get_DeviceID(int *deviceID)
+{
+    char mcu_address = (MMA8452_ADDRESS<<1);
+    int z = 0;
+    m_i2c.start();
+    wait( 0.1);
+    if( m_i2c.write( mcu_address) == 0) 
+    {
+        //printf( "GetDeviceId NAK on writing address");
+        return 1;
+    }
+    wait( 0.1);
+    if( m_i2c.write( WHO_AM_I) == 0) 
+    {
+        //printf( "GetDeviceId NAK on writing register address");
+
+        return 1;
+    }
+    wait( 0.1);
+    m_i2c.start();
+    wait( 0.1);
+    if( m_i2c.write( mcu_address | 0x01) == 0)          // this is asking to read the slave address - even though it's a 'write' method!!! Crap API...
+    {
+        //printf( "GetDeviceId NAK on writing address");
+
+        return 1;
+    }
+    wait( 0.1);
+    //deviceID  = m_i2c.read(0);
+    z = m_i2c.read(0);
+    wait( 0.1);
+    m_i2c.stop();
+    return 0;
+
+}
+
+
 // Reads the tilt angle
 void Accelerometer_MMA8452::read_Tilt(float *x, float *y, float *z)
 {
@@ -92,17 +132,17 @@
 // Reads x data
 int Accelerometer_MMA8452::read_x()
 {
-    char mcu_address = (MMA8452_ADDRESS <1);
+    char mcu_address = (MMA8452_ADDRESS <<1);
 
-    m_i2c.start();                  // Start
-    m_i2c.write(mcu_address);              // A write to device 0x98
-    m_i2c.write(OUT_X_MSB);             // Register to read
+    m_i2c.start();                      // Start
+    m_i2c.write(mcu_address);           // A write to devic
+    m_i2c.write(OUT_X_LSB);             // Register to read
     m_i2c.start();                  
-    m_i2c.write(mcu_address);              // Read from device 0x99
-    char x = m_i2c.read(0);         // Read the data
+    m_i2c.write(mcu_address);           // Read from device
+    int x = m_i2c.read(0);             // Read the data
     m_i2c.stop();
     
-    return (int)x;  
+    return x;  
 
 }
 
@@ -110,17 +150,17 @@
 // Reads y data
 int Accelerometer_MMA8452::read_y()
 {
-    char mcu_address = (MMA8452_ADDRESS <1);
+    char mcu_address = (MMA8452_ADDRESS <<1);
 
     m_i2c.start();                  // Start
     m_i2c.write(mcu_address);              // A write to device 0x98
     m_i2c.write(OUT_Y_MSB);             // Register to read
     m_i2c.start();                  
     m_i2c.write(mcu_address);              // Read from device 0x99
-    char y = m_i2c.read(0);         // Read the data
+    int y = m_i2c.read(0);         // Read the data
     m_i2c.stop();
     
-    return (int)y; 
+    return y; 
 
 }
 
@@ -128,25 +168,52 @@
 // Reads z data
 int Accelerometer_MMA8452::read_z()
 {
-    char mcu_address = (MMA8452_ADDRESS <1);
+    char mcu_address = (MMA8452_ADDRESS <<1);
     
     m_i2c.start();                  // Start
     m_i2c.write(mcu_address);              // A write to device 0x98
     m_i2c.write(OUT_Z_MSB);             // Register to read
     m_i2c.start();                  
     m_i2c.write(mcu_address);              // Read from device 0x99
-    char z = m_i2c.read(0);         // Read the data
+    int z = m_i2c.read(0);         // Read the data
     m_i2c.stop();
     
-    return (int)z;
+    return z;
 
 }
 
 
 // Reads xyz
-
+int Accelerometer_MMA8452::read_xyz(char *x, char *y, char *z) 
+{
+    
+    
+    char mcu_address = (MMA8452_ADDRESS <<1);
+    char register_buffer[6] ={0,0,0,0,0,0};
+    const char Addr_X = OUT_X_MSB;
+    m_i2c.write(mcu_address);              // A write to device 0x98
+    m_i2c.write(MMA8452_ADDRESS, &Addr_X, 1);         // Pointer to the OUT_X_MSB register
+    
+    if(m_i2c.write(mcu_address,&Addr_X,1) == 0)
+    {
+        if(m_i2c.read(mcu_address,register_buffer,6) == 0)
+        {
+            *x = register_buffer[1];
+            *y = register_buffer[3];
+            *z = register_buffer[5];
+            return 0;           // yahoooooo
+        }
+        else
+        {
+            return 1;           // failed oh nooo!
+        }    
+    }
+    else
+    {
+        return 1;               // failed oh nooo!
+    }
 
-
+}
 
         // Write register (The device must be placed in Standby Mode to change the value of the registers) 
 void Accelerometer_MMA8452::write_reg(char addr, char data)

--- a/MMA8452.h	Fri Oct 04 14:48:02 2013 +0000
+++ b/MMA8452.h	Tue Oct 08 15:25:32 2013 +0000
@@ -89,7 +89,7 @@
 
 #define FF_MT_CFG 0X15                      // Type 'read/write' : Freefaul motion functional block configuration
 #define FF_MT_SRC 0X16                      // Type 'read' : Freefaul motion event source register
-#define FF_COUNT 0X17                       // Type 'read' : Freefaul motion threshold register
+#define FF_MT_THS 0X17                      // Type 'read' : Freefaul motion threshold register
 #define FF_COUNT 0X18                       // Type 'read' : Freefaul motion debouce counter
 
 #define ASLP_COUNT 0x29                     // Type 'read/write' : Counter setting for auto sleep
@@ -126,7 +126,8 @@
         * @param scl I2C8452 clock port
         * 
         */ 
-      Accelerometer_MMA8452(PinName sda, PinName scl);
+      Accelerometer_MMA8452(PinName sda, PinName scl, int frequency);
+      //Accelerometer_MMA8452(PinName sda, PinName scl);
        
        /** Destroys an MMA8452 object
         *
@@ -134,16 +135,23 @@
       ~Accelerometer_MMA8452();
       
       /** Activate the MMA8452 (required)
-       *
-       *
-       */
+        *   returns 0 for success in activating the chip
+        *   returns 1 for failure in activating the chip
+        *   -currrently no retries or waiting is done, this method tries 1 time the exits.
+      */
       int activate();
       
        /** Initialization of device MMA8452 (required)
-        *
         */
       void init();
     
+       /** Read the device ID from the accelerometer
+        *
+        * @param *deviceID Value of device - is should be 0x2A
+        * return 0 for success or
+        * return 1 for failure.
+        */        
+      int Get_DeviceID(int *deviceID);    
        /** Read the Tilt Angle using Three Axis
         *
         * @param *x Value of x tilt
@@ -169,6 +177,15 @@
         * @returns The value of z acceleration
         */
        int read_z();
+      
+      /** Read the x,y and z registers of the MMA8452
+       *
+       * takes a 2 byte char buffer to store the value
+       * for each axis.
+       * returns 0 for success, and 1 for failure
+       *
+       */ 
+      int read_xyz(char *x, char *y, char *z); 
             
         /** Read from specified MMA8452 register
          *
@@ -187,7 +204,7 @@
    
     private:
       I2C m_i2c;
-      int m_frequencey;
+      int m_frequency;
          
 };