Revision 12:172540ff6b8b, committed 2014-03-04

Comitter:

ashleymills

Date:

Tue Mar 04 17:50:47 2014 +0000

Parent:

11:dfd1e0afcb7b

Child:

13:4bd8b4cd479d

Commit message:

Added basic raw reading back in after remake.

Changed in this revision

--- a/MMA8452.cpp	Tue Mar 04 16:23:40 2014 +0000
+++ b/MMA8452.cpp	Tue Mar 04 17:50:47 2014 +0000
@@ -25,11 +25,17 @@
 // Connect module at I2C address using I2C port pins sda and scl
 MMA8452::MMA8452(PinName sda, PinName scl, int frequency) : _i2c(sda, scl) , _frequency(frequency) {
    DBG("Creating MMA8452");
+   
+   // set I2C frequency
    _i2c.frequency(_frequency);
    
-   // setup read and write addresses to avoid duplication
+   // setup read and write addresses for convenience
    _readAddress   = MMA8452_ADDRESS | 0x01;
    _writeAddress  = MMA8452_ADDRESS & 0xFE;
+   
+   // set some defaults
+   _bitDepth = BIT_DEPTH_UNKNOWN;
+   setBitDepth(BIT_DEPTH_12);
    DBG("Done");
 }
 
@@ -40,13 +46,13 @@
 // Setting the control register bit 1 to true to activate the MMA8452
 int MMA8452::activate() {
     // perform write and return error code
-    return logicalORRegister(CTRL_REG_1,MMA8452_ACTIVE_MASK);
+    return logicalORRegister(MMA8452_CTRL_REG_1,MMA8452_ACTIVE_MASK);
 }
 
 // Setting the control register bit 1 to 0 to standby the MMA8452
 int MMA8452::standby() {
     // perform write and return error code
-    return logicalANDRegister(CTRL_REG_1,MMA8452_STANDBY_MASK);
+    return logicalANDRegister(MMA8452_CTRL_REG_1,MMA8452_STANDBY_MASK);
 }
 
 // this reads a register, applies a bitmask with logical AND, sets a value with logical OR,
@@ -102,6 +108,7 @@
 }
 
 int MMA8452::setBitDepth(BitDepth depth,int toggleActivation) {
+   _bitDepth = depth;
    return maskAndApplyRegister(
       MMA8452_CTRL_REG_1,
       MMA8452_BIT_DEPTH_MASK,
@@ -110,105 +117,25 @@
    );
 }
 
-
-// Get device ID 
-int MMA8452::getDeviceID(char *dst)
-{
-    return readRegister(WHO_AM_I,dst);
+int MMA8452::isXYZReady() {
+   char rval = 0;
+   if(readRegister(MMA8452_STATUS,&rval)) {
+      return 0;
+   }
+   return (rval&MMA8452_STATUS_ZYXDR_MASK);
 }
-
-
-int MMA8452::readRaw(char src, char *dst, int len) {
-    // this is the register we want to get data from               
-    char register_address[1];
-    register_address[0] = src;
-    
-    if(_i2c.write(_writeAddress,register_address,1,true) == 0)
-    {
-        if(_i2c.read(_readAddress,dst,len)==0)
-        {
-           return 0;
-        }
-    }
-    
-    // failure case, zero array and return error
-    for(int i=0; i<len; i++) {
-       dst[i] = 0x00;
-    }
-    return 1;   
-}
-
-// Reads x data. This method reads two registers containing the x-axis values from the accelerometer. 
-// It takes a 2 byte char array and copies the register values into the buffer. If it fails the char array
-// is set to '0'. It returns '0' success '1' fail. This method does nothing to the registers - just returns
-// the raw data.
-//int MMA8452::read_x(int& xaxisLSB)
-int MMA8452::readRawX(char *xaxis) {   
-    return readRaw(OUT_X_MSB,xaxis,2);  
-}
-
-
-// Reads y data. This method reads two registers containing the x-axis values from the accelerometer. 
-// It takes a 2 byte char array and copies the register values into the buffer. If it fails the char array
-// is set to '0'. It returns '0' success '1' fail. This method does nothing to the registers - just returns
-// the raw data.
-
-int MMA8452::readRawY(char *yaxis) {
-   return readRaw(OUT_Y_MSB,yaxis,2);
+ 
+int MMA8452::getDeviceID(char *dst) {
+   return readRegister(MMA8452_WHO_AM_I,dst);
 }
 
-
-
-// Reads z data. This method reads two registers containing the x-axis values from the accelerometer. 
-// It takes a 2 byte char array and copies the register values into the buffer. If it fails the char array
-// is set to '0'. It returns '0' success '1' fail. This method does nothing to the registers - just returns
-// the raw data.
-
-int MMA8452::readRawZ(char *zaxis)
-{
-   return readRaw(OUT_Z_MSB,zaxis,2);
+int MMA8452::getStatus(char* dst) {
+   return readRegister(MMA8452_STATUS,dst);
 }
 
-
-
-// Reads y data
-int MMA8452::read_y()
-{
-    char mcu_address = (MMA8452_ADDRESS <<1);
-
-    _i2c.start();                  // Start
-    _i2c.write(mcu_address);              // A write to device 0x98
-    _i2c.write(OUT_Y_MSB);             // Register to read
-    _i2c.start();                  
-    _i2c.write(mcu_address);              // Read from device 0x99
-    int y = _i2c.read(0);         // Read the data
-    _i2c.stop();
-    
-    return y; 
-
-}
-
-// Reads z data
-int MMA8452::read_z()
-{
-    char mcu_address = (MMA8452_ADDRESS <<1);
-    
-    _i2c.start();                  // Start
-    _i2c.write(mcu_address);              // A write to device 0x98
-    _i2c.write(OUT_Z_MSB);             // Register to read
-    _i2c.start();                  
-    _i2c.write(mcu_address);              // Read from device 0x99
-    int z = _i2c.read(0);         // Read the data
-    _i2c.stop();
-    
-    return z;
-
-}
-
-
 MMA8452::DynamicRange MMA8452::getDynamicRange() {
    char rval = 0;
-   if(readRegister(MMA8452_CTRL_REG_1,&rval)) {
+   if(readRegister(MMA8452_XYZ_DATA_CFG,&rval)) {
       return MMA8452::DYNAMIC_RANGE_UNKNOWN;
    }
    rval &= (MMA8452_DYNAMIC_RANGE_MASK^0xFF);
@@ -228,35 +155,15 @@
 }
 
 // Reads xyz
-int MMA8452::readRawXYZ(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;
-    _i2c.write(mcu_address);              // A write to device 0x98
-    _i2c.write(MMA8452_ADDRESS, &Addr_X, 1);         // Pointer to the OUT_X_MSB register
-    
-    if(_i2c.write(mcu_address,&Addr_X,1) == 0)
-    {
-        if(_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!
-    }
-
+int MMA8452::readRawXYZ(char *dst) {
+   if(_bitDepth==BIT_DEPTH_UNKNOWN) {
+      return 1;
+   }
+   int readLen = 3;
+   if(_bitDepth==BIT_DEPTH_12) {
+      readLen = 6;
+   }
+   return readRegister(MMA8452_OUT_X_MSB,dst,readLen);
 }
 
 // apply an AND mask to a register. read register value, apply mask, write it back
@@ -284,7 +191,6 @@
    return writeRegister(addr,value);
 }
 
-
 // apply an OR mask to a register. read register value, apply mask, write it back
 int MMA8452::logicalXORRegister(char addr, char mask) {
    char value = 0;
@@ -367,7 +273,7 @@
    // get register value
    char v = 0;
    if(readRegister(reg,&v)) {
-      DBG("Error reading control register");
+      DBG("Error reading specified register");
       return;
    }
    // print out details
@@ -410,6 +316,18 @@
          }
       break;
       
+      case MMA8452_STATUS:
+         DBG("STATUS has value: 0x%x",v);
+         DBG(" 7  ZYXOW: %d",(v&0x80)>>7);
+         DBG(" 6  ZOW: %d",  (v&0x40)>>6);
+         DBG(" 5  YOW: %d",  (v&0x20)>>5);
+         DBG(" 4  XOW: %d",  (v&0x10)>>4);
+         DBG(" 3  ZYXDR: %d",(v&0x08)>>3);
+         DBG(" 2  ZDR: %d",  (v&0x04)>>2);
+         DBG(" 1  YDR: %d",  (v&0x02)>>1);
+         DBG(" 0  XDR: %d",  (v&0x01));
+      break;
+      
       default:
          DBG("Unknown register address: 0x%x",reg);
       break;

--- a/MMA8452.h	Tue Mar 04 16:23:40 2014 +0000
+++ b/MMA8452.h	Tue Mar 04 17:50:47 2014 +0000
@@ -74,42 +74,44 @@
 #endif
 
 // Register descriptions found in section 6 of pdf
-#define STATUS 0x00                         // Type 'read' : Real time status, should return 0x00
-#define OUT_X_MSB 0x01                      // Type 'read' : x axis - 8 most significatn bit of a 12 bit sample
-#define OUT_X_LSB 0x02                      // Type 'read' : x axis - 4 least significatn bit of a 12 bit sample
-#define OUT_Y_MSB 0x03                      // Type 'read' : y axis - 8 most significatn bit of a 12 bit sample
-#define OUT_Y_LSB 0x04                      // Type 'read' : y axis - 4 least significatn bit of a 12 bit sample
-#define OUT_Z_MSB 0x05                      // Type 'read' : z axis - 8 most significatn bit of a 12 bit sample
-#define OUT_Z_LSB 0x06                      // Type 'read' : z axis - 4 least significatn bit of a 12 bit sample
+#define MMA8452_STATUS 0x00                 // Type 'read' : Status of the data registers
+#define MMA8452_OUT_X_MSB 0x01              // Type 'read' : x axis - MSB of 2 byte sample
+#define MMA8452_OUT_X_LSB 0x02              // Type 'read' : x axis - LSB of 2 byte sample
+#define MMA8452_OUT_Y_MSB 0x03              // Type 'read' : y axis - MSB of 2 byte sample
+#define MMA8452_OUT_Y_LSB 0x04              // Type 'read' : y axis - LSB of 2 byte sample
+#define MMA8452_OUT_Z_MSB 0x05              // Type 'read' : z axis - MSB of 2 byte sample
+#define MMA8452_OUT_Z_LSB 0x06              // Type 'read' : z axis - LSB of 2 byte sample
 
-#define SYSMOD 0x0B                         // Type 'read' : This tells you if device is active, sleep or standy 0x00=STANDBY 0x01=WAKE 0x02=SLEEP
-#define WHO_AM_I 0x0D                       // Type 'read' : This should return the device id of 0x2A
+// register definitions
+#define MMA8452_XYZ_DATA_CFG 0x0E
+
+#define MMA8452_SYSMOD 0x0B                         // Type 'read' : This tells you if device is active, sleep or standy 0x00=STANDBY 0x01=WAKE 0x02=SLEEP
+#define MMA8452_WHO_AM_I 0x0D                       // Type 'read' : This should return the device id of 0x2A
 
-#define PL_STATUS 0x10                      // Type 'read' : This shows portrait landscape mode orientation
-#define PL_CFG 0x11                         // Type 'read/write' : This allows portrait landscape configuration
-#define PL_COUNT 0x12                       // Type 'read' : This is the portraint landscape debounce counter
-#define PL_BF_ZCOMP 0x13                    // Type 'read' :
-#define PL_THS_REG 0x14                     // Type 'read' :
+#define MMA8452_PL_STATUS 0x10                      // Type 'read' : This shows portrait landscape mode orientation
+#define MMA8452_PL_CFG 0x11                         // Type 'read/write' : This allows portrait landscape configuration
+#define MMA8452_PL_COUNT 0x12                       // Type 'read' : This is the portraint landscape debounce counter
+#define MMA8452_PL_BF_ZCOMP 0x13                    // Type 'read' :
+#define MMA8452_PL_THS_REG 0x14                     // Type 'read' :
 
-#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_MT_THS 0X17                      // Type 'read' : Freefaul motion threshold register
-#define FF_COUNT 0X18                       // Type 'read' : Freefaul motion debouce counter
+#define MMA8452_FF_MT_CFG 0X15                      // Type 'read/write' : Freefaul motion functional block configuration
+#define MMA8452_FF_MT_SRC 0X16                      // Type 'read' : Freefaul motion event source register
+#define MMA8452_FF_MT_THS 0X17                      // Type 'read' : Freefaul motion threshold register
+#define MMA8452_FF_COUNT 0X18                       // Type 'read' : Freefaul motion debouce counter
 
-#define ASLP_COUNT 0x29                     // Type 'read/write' : Counter settings for auto sleep
-#define CTRL_REG_1 0x2A                     // Type 'read/write' :
-#define CTRL_REG_2 0x2B                     // Type 'read/write' :
-#define CTRL_REG_3 0x2C                     // Type 'read/write' :
-#define CTRL_REG_4 0x2D                     // Type 'read/write' :
-#define CTRL_REG_5 0x2E                     // Type 'read/write' :
+#define MMA8452_ASLP_COUNT 0x29                     // Type 'read/write' : Counter settings for auto sleep
+#define MMA8452_CTRL_REG_1 0x2A                     // Type 'read/write' :
+#define MMA8452_CTRL_REG_2 0x2B                     // Type 'read/write' :
+#define MMA8452_CTRL_REG_3 0x2C                     // Type 'read/write' :
+#define MMA8452_CTRL_REG_4 0x2D                     // Type 'read/write' :
+#define MMA8452_CTRL_REG_5 0x2E                     // Type 'read/write' :
 
 // Defined in table 13 of the Freescale PDF
+/// xxx these all need to have better names
 #define STANDBY 0x00                        // State value returned after a SYSMOD request, it can be in state STANDBY, WAKE or SLEEP
 #define WAKE 0x01                           // State value returned after a SYSMOD request, it can be in state STANDBY, WAKE or SLEEP
 #define SLEEP 0x02                          // State value returned after a SYSMOD request, it can be in state STANDBY, WAKE or SLEEP
 #define ACTIVE 0x01                         // Stage value returned and set in Control Register 1, it can be STANDBY=00, or ACTIVE=01
-
-
  
 #define TILT_STATUS 0x03        // Tilt Status (Read only)
 #define SRST_STATUS 0x04        // Sample Rate Status Register (Read only)
@@ -120,23 +122,27 @@
 #define PDET_STATUS 0x09        // Tap/Pulse Detection Register (Read/Write)
 #define PD_STATUS 0xA           // Tap/Pulse Debounce Count Register (Read/Write)
  
+// masks for enabling/disabling standby
 #define MMA8452_ACTIVE_MASK 0x01
 #define MMA8452_STANDBY_MASK 0xFE
- 
-#define MMA8452_XYZ_DATA_CFG 0x0E
-#define MMA8452_CTRL_REG_1 0x2A
 
+// mask for dynamic range reading and writing
 #define MMA8452_DYNAMIC_RANGE_MASK 0xFC
 
-
+// mask and shift for data rate reading and writing
 #define MMA8452_DATA_RATE_MASK 0xC7
 #define MMA8452_DATA_RATE_MASK_SHIFT 0x03
 
+// mask and shift for general reading and writing
 #define MMA8452_WRITE_MASK 0xFE
 #define MMA8452_READ_MASK 0x01
 
+// mask and shift for bit depth reading and writing
 #define MMA8452_BIT_DEPTH_MASK 0xFD
 #define MMA8452_BIT_DEPTH_MASK_SHIFT 0x01
+
+// status masks and shifts
+#define MMA8452_STATUS_ZYXDR_MASK 0x08
  
 class MMA8452         
 {        
@@ -151,7 +157,8 @@
         
        enum BitDepth {
            BIT_DEPTH_12=0x00,
-           BIT_DEPTH_8 // 1 sets fast read mode, hence the inversion
+           BIT_DEPTH_8, // 1 sets fast read mode, hence the inversion
+           BIT_DEPTH_UNKNOWN
        };
        
        enum DataRateHz {
@@ -228,21 +235,19 @@
         */        
       int getDeviceID(char* dst);  
       
-      int read_y();
-      
-      int read_z();  
+      int getStatus(char* dst);  
 
       /** Read the x register of the MMA8452
         *
         * @returns The value of x acceleration
         */
-      int readRawX(char *xaxis);
-      //int read_x(int& xaxisLSB);
+      int readRawX(char *dst);
+      
       /** Read the y register of the MMA8452
-        *
-        * @returns The value of y acceleration
-        */
-      int readRawY(char *yaxis);
+       * @param dst The destination buffer
+       * @returns The value of y acceleration
+       */
+      int readRawY(char *dst);
       
       /** Read the z register of the MMA8452
         *
@@ -250,30 +255,41 @@
         */
        int readRawZ(char * zaxis);
       
-      /** Read the x,y and z registers of the MMA8452
+      /** 
+       * 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
-       *
+       * @param dst The destination buffer. Note that this needs to be 3 bytes for
+       * BIT_DEPTH_8 and 6 bytes for BIT_DEPTH_12. It is upto the caller to ensure this.
+       * @return 0 for success, and 1 for failure
        */ 
-      int readRawXYZ(char *x, char *y, char *z); 
+      int readRawXYZ(char *dst); 
+      
+      int isXYZReady();
             
-        /** Read from specified MMA8452 register
-         *
-         * @param addr The internal registeraddress of the MMA8452
-         * @returns The value of the register
-         */
+      /** Read from specified MMA8452 register
+       *
+       * @param addr The internal registeraddress of the MMA8452
+       * @return The value of the register
+       */
       int readRegister(char addr, char *dst);
       
       int readRegister(char addr, char *dst, int nbytes);
         
-        /** Write to specified MMA8452 register
+       /** 
+        * Write to the specified MMA8452 register.
         *
-        * @param addr The internal registeraddress of the MMA8452
-        * @param data New value of the register
+        * @param addr The internal register address
+        * @param data Data to write
         */    
       int writeRegister(char addr, char data);
+      
+       /** 
+        * Write a data buffer to the specified MMA8452 register.
+        *
+        * @param addr The internal register address
+        * @param data Data buffer to write
+        * @param nbytes The length of the data buffer to write
+        */    
       int writeRegister(char addr, char *data, int nbytes);
       
       int logicalANDRegister(char addr, char mask);
@@ -285,6 +301,7 @@
       int setDataRate(DataRateHz dataRate, int toggleActivation=1);
       DynamicRange getDynamicRange();
       DataRateHz getDataRate();
+      BitDepth getBitDepth();
       
       void debugRegister(char reg);
    
@@ -296,6 +313,8 @@
       int _frequency;
       int _readAddress;
       int _writeAddress;
+      
+      BitDepth _bitDepth;
          
 };