FXOS8700CQ.hpp

00001 /**
00002  * @file FXOS8700CQ.hpp
00003  * @author Weimen Li
00004  * @date June 5th, 2016
00005  * @class FXOS8700CQ
00006  * @brief This class represents the FXOS8700CQ sensor. Only accelerometer reading is currently supported.
00007  * @remark WARNING: I2C Reading is unreliable when built outside of the mbed compiler. If you're compiling this outside
00008  * of the mBed compiler, ensure that the accelerometer is reading reliably. My testing shows that the readings often glitch.
00009  */
00010 
00011 #ifndef FXOS8700CQ_HPP_
00012 #define FXOS8700CQ_HPP_
00013 #include <mbed.h>
00014 
00015 class FXOS8700CQ {
00016 public:
00017     /// Possible accelerometer sensitivity settings.
00018     enum AccelerometerSensitivity {TWO, FOUR, EIGHT};
00019     /**
00020      * @brief Constructor for the FXOS8700CQ Accelerometer/Magnetometer. Pin assignments have default values for the K22F board.
00021      * @param SDA The SDA Pin.
00022      * @param SCL the SCL Pin.
00023      * @param INT1 The pin that the INT1 line is connected to.
00024      * @param INT2 The pin that the INT2 line is connect to.
00025      * @param setting (optional) The maximum measurement acceleration in g's. May be TWO, FOUR, or EIGHT for
00026      * +/- 2/4/8 g's. A smaller maximum measurement allows for greater sensitivity.
00027      */
00028     FXOS8700CQ(PinName SDA = PTB3, PinName SCL = PTB2, PinName INT1 = PTD0, PinName INT2 = PTD1, AccelerometerSensitivity setting = TWO);
00029     virtual ~FXOS8700CQ();
00030     /**
00031      * @brief Read data from the accelerometer. Takes pointers to floats that store these variables.
00032      * Example code:
00033      * @code
00034      * float xAccel;
00035      * float yAccel;
00036      * float zAccel;
00037      * ...
00038      * readAccelerometer(&xAccel, &yAccel, &zAccel);
00039      * ...
00040      * @endcode
00041      */
00042     void readAccelerometer(float *xAccel, float *yAccel, float *zAccel);
00043     /**
00044      * @brief Set offset compensation values that are subtracted from the readings to zero them. 
00045      */
00046      void setOffset(float x, float y, float z) {
00047         xOffset = x;
00048         yOffset = y;
00049         zOffset = z;
00050      }
00051 private:
00052     /// Member function to handle data-ready interrupt.
00053     void dataReadyISR(void);
00054 private:
00055     /// I2C Object to handle bus communications.
00056     I2C I2CObj;
00057     /// Interrupt object for a data-ready signal.
00058     InterruptIn dataReadyInt;
00059     /// The accelerometer sensitivity setting specified by the caller.
00060     const AccelerometerSensitivity accelSensitivitySetting;
00061     /// The conversion constant to convert the read int16_t type data to a float.
00062     const float accelInt2Float;
00063     /// The latest x Acceleration value in g's.
00064     float lastxAccel;
00065     /// The latest y Acceleration value in g's.
00066     float lastyAccel;
00067     /// The latest z Acceleration values in g's.
00068     float lastzAccel;
00069     /// The x offset
00070     float xOffset;
00071     /// The y offset
00072     float yOffset;
00073     /// The z offset
00074     float zOffset;
00075 };
00076 
00077 #endif /* FXOS8700CQ_HPP_ */
00078