Diff: MMA8452.h

Revision:

0:f10415100c39

diff -r 000000000000 -r f10415100c39 MMA8452.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/MMA8452.h	Mon Feb 11 04:31:13 2019 +0000
@@ -0,0 +1,344 @@
+#pragma once
+ 
+// Authors: Ashley Mills, Nicholas Herriot
+/* Copyright (c) 2013 Vodafone, MIT License
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of this software
+ * and associated documentation files (the "Software"), to deal in the Software without restriction,
+ * including without limitation the rights to use, copy, modify, merge, publish, distribute,
+ * sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all copies or
+ * substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
+ * BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+ * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+ 
+// the SparkFun breakout board defaults to 1, set to 0 if SA0 jumper on the bottom of the board is set
+// see the Table 10. I2C Device Address Sequence in Freescale MMA8452Q pdf
+ 
+#include "mbed.h" 
+ 
+#define MMA8452_DEBUG 1
+ 
+// More info on MCU Master address can be found on section 5.10.1 of http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=MMA8452Q
+#define SA0 1
+#if SA0
+  #define MMA8452_ADDRESS 0x3A // 0x1D<<1  // SA0 is high, 0x1C if low - 
+#else
+  #define MMA8452_ADDRESS 0x38 // 0x1C<<1
+#endif
+ 
+// Register descriptions found in section 6 of pdf
+#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
+ 
+// 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 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 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 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)
+#define SPCNT_STATUS 0x05       // Sleep Count Register (Read/Write)
+#define INTSU_STATUS 0x06       // Interrupt Setup Register
+#define MODE_STATUS 0x07        // Mode Register (Read/Write)
+#define SR_STATUS 0x08          // Auto-Wake and Active Mode Portrait/Landscape Samples per Seconds Register (Read/Write)
+#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
+ 
+// 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
+#define MMA8452_STATUS_ZDR_MASK 0x04
+#define MMA8452_STATUS_YDR_MASK 0x02
+#define MMA8452_STATUS_XDR_MASK 0x01
+ 
+/**
+ * Wrapper for the MMA8452 I2C driven accelerometer.
+ */
+class MMA8452 {
+            
+    public:
+    
+       enum DynamicRange {
+           DYNAMIC_RANGE_2G=0x00,
+           DYNAMIC_RANGE_4G,
+           DYNAMIC_RANGE_8G,
+           DYNAMIC_RANGE_UNKNOWN
+       };
+        
+       enum BitDepth {
+           BIT_DEPTH_12=0x00,
+           BIT_DEPTH_8, // 1 sets fast read mode, hence the inversion
+           BIT_DEPTH_UNKNOWN
+       };
+       
+       enum DataRateHz {
+          RATE_800=0x00,
+          RATE_400,
+          RATE_200,
+          RATE_100,
+          RATE_50,
+          RATE_12_5,
+          RATE_6_25,
+          RATE_1_563,
+          RATE_UNKNOWN
+       };
+         
+       /**
+        * Create an accelerometer object connected to the specified I2C pins.
+        *
+        * @param sda I2C data port
+        * @param scl I2C clock port
+        * @param frequency 
+        * 
+        */ 
+      MMA8452(PinName sda, PinName scl, int frequency);
+       
+      /// Destructor
+      ~MMA8452();
+      
+      /**
+       * Puts the MMA8452 in active mode.
+       * @return 0 on success, 1 on failure.
+       */
+      int activate();
+ 
+      /**
+       * Puts the MMA8452 in standby.
+       * @return 0 on success, 1 on failure.
+       */
+      int standby();      
+    
+       /**
+        * Read the device ID from the accelerometer (should be 0x2a)
+        *
+        * @param dst pointer to store the ID
+        * @return 0 on success, 1 on failure.
+        */        
+      int getDeviceID(char* dst);  
+      
+      /**
+       * Read the MMA8452 status register.
+       *
+       * @param dst pointer to store the register value.
+       * @ return 0 on success, 1 on failure.
+       */
+      int getStatus(char* dst);  
+      
+      /** 
+       * Read the raw x, y, an z registers of the MMA8452 in one operation.
+       * All three registers are read sequentially and stored in the provided buffer.
+       * The stored values are signed 2's complement left-aligned 12 or 8 bit integers.
+       *
+       * @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
+       * @sa setBitDepth
+       */ 
+      int readXYZRaw(char *dst);
+      
+      /// Read the raw x register into the provided buffer. @sa readXYZRaw
+      int readXRaw(char *dst);
+      /// Read the raw y register into the provided buffer. @sa readXYZRaw
+      int readYRaw(char *dst);
+      /// Read the raw z register into the provided buffer. @sa readXYZRaw
+      int readZRaw(char *dst);
+      
+      /**
+       * Read the x, y, and z signed counts of the MMA8452 axes.
+       * 
+       * Count resolution is either 8 bits or 12 bits, and the range is either +-2G, +-4G, or +-8G
+       * depending on settings. The number of counts per G are 1024, 512, 256 for 2,4, and 8 G
+       * respectively at 12 bit resolution and 64, 32, 16 for 2, 4, and 8 G respectively at
+       * 8 bit resolution.
+       * 
+       * This function queries the MMA8452 and returns the signed counts for each axes.
+       *
+       * @param x Pointer to integer to store x count
+       * @param y Pointer to integer to store y count
+       * @param z Pointer to integer to store z count
+       * @return 0 on success, 1 on failure.
+       */
+      int readXYZCounts(int *x, int *y, int *z);
+      
+      /// Read the x axes signed count. @sa readXYZCounts
+      int readXCount(int *x);
+      /// Read the y axes signed count. @sa readXYZCounts
+      int readYCount(int *y);
+      /// Read the z axes signed count. @sa readXYZCounts
+      int readZCount(int *z);
+      
+      /**
+       * Read the x, y, and z accelerations measured in G.
+       *
+       * The measurement resolution is controlled via setBitDepth which can
+       * be 8 or 12, and by setDynamicRange, which can be +-2G, +-4G, or +-8G.
+       *
+       * @param x A pointer to the double to store the x acceleration in.
+       * @param y A pointer to the double to store the y acceleration in.
+       * @param z A pointer to the double to store the z acceleration in.
+       *
+       * @return 0 on success, 1 on failure.
+       */
+      int readXYZGravity(double *x, double *y, double *z);
+      
+      /// Read the x gravity in G into the provided double pointer. @sa readXYZGravity
+      int readXGravity(double *x);
+      /// Read the y gravity in G into the provided double pointer. @sa readXYZGravity
+      int readYGravity(double *y);
+      /// Read the z gravity in G into the provided double pointer. @sa readXYZGravity
+      int readZGravity(double *z);
+      
+      /// Returns 1 if data has been internally sampled (is available) for all axes since last read, 0 otherwise.
+      int isXYZReady();
+      /// Returns 1 if data has been internally sampled (is available) for the x-axis since last read, 0 otherwise.
+      int isXReady();
+      /// Returns 1 if data has been internally sampled (is available) for the y-axis since last read, 0 otherwise.
+      int isYReady();
+      /// Returns 1 if data has been internally sampled (is available) for the z-axis since last read, 0 otherwise.
+      int isZReady();
+            
+      /** 
+       * Reads a single byte from the specified MMA8452 register.
+       *
+       * @param addr The internal register address.
+       * @param dst The destination buffer address.
+       * @return 1 on success, 0 on failure.
+       */
+      int readRegister(char addr, char *dst);
+      
+      /** 
+       * Reads n bytes from the specified MMA8452 register.
+       *
+       * @param addr The internal register address.
+       * @param dst The destination buffer address.
+       * @param nbytes The number of bytes to read.
+       * @return 1 on success, 0 on failure.
+       */
+      int readRegister(char addr, char *dst, int nbytes);
+        
+       /** 
+        * Write to the specified MMA8452 register.
+        *
+        * @param addr The internal register address
+        * @param data Data byte 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 Pointer to data buffer to write
+        * @param nbytes The length of the data buffer to write
+        */    
+      int writeRegister(char addr, char *data, int nbytes);
+      
+      int setDynamicRange(DynamicRange range, int toggleActivation=1);
+      int setBitDepth(BitDepth depth, int toggleActivation=1);
+      int setDataRate(DataRateHz dataRate, int toggleActivation=1);
+      
+      DynamicRange getDynamicRange();
+      DataRateHz getDataRate();
+      BitDepth getBitDepth();
+      
+      #ifdef MMA8452_DEBUG
+      void debugRegister(char reg);
+      #endif
+   
+    private:
+      /**
+       * Reads the specified register, applies the mask with logical AND, logical ORs the value
+       * and writes back the result to the register. If toggleActivation is set to true then the
+       * device is put in standby before the operation, and activated at the end.
+       * Setting it to false is useful for setting options on a device that you want to keep in
+       * standby.
+       */
+      int maskAndApplyRegister(char reg, char mask, char value, int toggleActivation);
+      
+      /// Reads the specified register, applies the mask with logical AND, and writes the result back.
+      int logicalANDRegister(char addr, char mask);
+      /// Reads the specified register, applies the mask with logical OR, and writes the result back.
+      int logicalORRegister(char addr, char mask);
+      /// Reads the specified register, applies the mask with logical XOR, and writes the result back.
+      int logicalXORRegister(char addr, char mask);
+      
+      /// Converts the 12-bit two's complement number in buf to a signed integer. Returns the integer.
+      int twelveBitToSigned(char *buf);
+      /// Converts the 8-bit two's complement number in buf to a signed integer. Returns the integer.
+      int eightBitToSigned(char *buf);
+      
+      /// Converts a count to a gravity using the supplied countsPerG. Returns the gravity.
+      double convertCountToGravity(int count, int countsPerG);
+      
+      /// Reads the register at addr, applies the mask with logical AND, and returns the result.
+      char getMaskedRegister(int addr, char mask);
+      
+      /// Get the counts per G for the current settings of bit depth and dynamic range.
+      int getCountsPerG();
+    
+      I2C _i2c;
+      int _frequency;
+      int _readAddress;
+      int _writeAddress;
+      
+      BitDepth _bitDepth;
+      DynamicRange _dynamicRange;       
+};
+            
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