MMA7660.h

00001 /* Copyright (c) <year> <copyright holders>, MIT License
00002  *
00003  * Permission is hereby granted, free of charge, to any person obtaining a copy of this software
00004  * and associated documentation files (the "Software"), to deal in the Software without restriction,
00005  * including without limitation the rights to use, copy, modify, merge, publish, distribute,
00006  * sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
00007  * furnished to do so, subject to the following conditions:
00008  *
00009  * The above copyright notice and this permission notice shall be included in all copies or
00010  * substantial portions of the Software.
00011  *
00012  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
00013  * BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
00014  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
00015  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
00016  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
00017  */
00018 
00019 #include "mbed.h"
00020 
00021 
00022 #ifndef MMA7660_H
00023 #define MMA7660_H
00024 
00025 #define MMA7660_ADDRESS     0x98
00026 #define MMA7660_SENSITIVITY 21.33
00027 
00028 #define MMA7660_XOUT_R      0x00
00029 #define MMA7660_YOUT_R      0x01
00030 #define MMA7660_ZOUT_R      0x02
00031 #define MMA7660_TILT_R      0x03
00032 #define MMA7660_INT_R       0x06
00033 #define MMA7660_MODE_R      0x07
00034 #define MMA7660_SR_R        0x08
00035 
00036 
00037 /** An interface for the MMA7660 triple axis accelerometer
00038  *
00039  * @code
00040  * //Uses the measured z-acceleration to drive leds 2 and 3 of the mbed
00041  *
00042  * #include "mbed.h"
00043  * #include "MMA7660.h"
00044  *
00045  * MMA7660 MMA(p28, p27);
00046  *
00047  * DigitalOut connectionLed(LED1);
00048  * PwmOut Zaxis_p(LED2);
00049  * PwmOut Zaxis_n(LED3);
00050  *
00051  * int main() {
00052  *     if (MMA.testConnection())
00053  *         connectionLed = 1;
00054  *
00055  *     while(1) {
00056  *         Zaxis_p = MMA.z();
00057  *         Zaxis_n = -MMA.z();
00058  *     }
00059  *
00060  * }
00061  * @endcode
00062  */
00063 class MMA7660
00064 {
00065 public:
00066     /**
00067     * The 6 different orientations and unknown
00068     *
00069     * Up & Down = X-axis
00070     * Right & Left = Y-axis
00071     * Back & Front = Z-axis
00072     *
00073     */
00074     enum Orientation {Up, Down,
00075                       Right, Left,
00076                       Back, Front,
00077                       Unknown
00078                      };
00079 
00080     /**
00081     * Creates a new MMA7660 object
00082     *
00083     * @param sda - I2C data pin
00084     * @param scl - I2C clock pin
00085     * @param active - true (default) to enable the device, false to keep it standby
00086     * @param asynch - use asynch i2c - the API is blocking which does not break the current app
00087     */
00088     MMA7660(PinName sda, PinName scl, bool active = true, bool asynch = false);
00089 
00090     /**
00091     * Tests if communication is possible with the MMA7660
00092     *
00093     * Because the MMA7660 lacks a WHO_AM_I register, this function can only check
00094     * if there is an I2C device that responds to the MMA7660 address
00095     *
00096     * @param return - true for successfull connection, false for no connection
00097     */
00098     bool testConnection( void );
00099 
00100     /**
00101     * Sets the active state of the MMA7660
00102     *
00103     * Note: This is unrelated to awake/sleep mode
00104     *
00105     * @param state - true for active, false for standby
00106     */
00107     void setActive( bool state);
00108 
00109     /**
00110     * Reads acceleration data from the sensor
00111     *
00112     * When the parameter is a pointer to an integer array it will be the raw data.
00113     * When it is a pointer to a float array it will be the acceleration in g's
00114     *
00115     * @param data - pointer to array with length 3 where the acceleration data will be stored, X-Y-Z
00116     */
00117     void readData( int *data);
00118     void readData( float *data);
00119 
00120     /**
00121     * Get X-data
00122     *
00123     * @param return - X-acceleration in g's
00124     */
00125     float x( void );
00126 
00127     /**
00128     * Get Y-data
00129     *
00130     * @param return - Y-acceleration in g's
00131     */
00132     float y( void );
00133 
00134     /**
00135     * Get Z-data
00136     *
00137     * @param return - Z-acceleration in g's
00138     */
00139     float z( void );
00140 
00141     /**
00142     * Sets the active samplerate
00143     *
00144     * The entered samplerate will be rounded to nearest supported samplerate.
00145     * Supported samplerates are: 120 - 64 - 32 - 16 - 8 - 4 - 2 - 1 samples/second.
00146     *
00147     * @param samplerate - the samplerate that will be set
00148     */
00149     void setSampleRate(int samplerate);
00150 
00151     /**
00152     * Returns if it is on its front, back, or unknown side
00153     *
00154     * This is read from MMA7760s registers, page 12 of datasheet
00155     *
00156     * @param return - Front, Back or Unknown orientation
00157     */
00158     Orientation getSide( void );
00159 
00160     /**
00161     * Returns if it is on it left, right, down or up side
00162     *
00163     * This is read from MMA7760s registers, page 12 of datasheet
00164     *
00165     * @param return - Left, Right, Down, Up or Unknown orientation
00166     */
00167     Orientation getOrientation ( void );
00168 
00169 
00170 private:
00171 
00172     void callback(int event);
00173 
00174     /**
00175     * Writes data to the device
00176     *
00177     * @param adress - register address to write to
00178     * @param data - data to write
00179     */
00180     void write( char address, char data);
00181 
00182     /**
00183     * Read data from the device
00184     *
00185     * @param adress - register address to write to
00186     * @return - data from the register specified by RA
00187     */
00188     char read( char adress);
00189 
00190     /**
00191      * Read multiple regigsters from the device, more efficient than using multiple normal reads.
00192      *
00193      * @param adress - register address to write to
00194      * @param length - number of bytes to read
00195      * @param data - pointer where the data needs to be written to
00196      */
00197     void read( char adress, char *data, int length);
00198 
00199     /**
00200     * Reads single axis
00201     */
00202     float getSingle(int number);
00203 
00204     I2C _i2c;
00205     bool active;
00206     float samplerate;
00207     volatile bool callback_done;
00208     event_callback_t event;
00209     const bool asynch;
00210 };
00211 
00212 
00213 #endif