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     */
00087     MMA7660(PinName sda, PinName scl, bool active = true);
00088 
00089     /**
00090     * Tests if communication is possible with the MMA7660
00091     *
00092     * Because the MMA7660 lacks a WHO_AM_I register, this function can only check
00093     * if there is an I2C device that responds to the MMA7660 address
00094     *
00095     * @param return - true for successfull connection, false for no connection
00096     */
00097     bool testConnection( void );
00098 
00099     /**
00100     * Sets the active state of the MMA7660
00101     *
00102     * Note: This is unrelated to awake/sleep mode
00103     *
00104     * @param state - true for active, false for standby
00105     */
00106     void setActive( bool state);
00107 
00108     /**
00109     * Reads acceleration data from the sensor
00110     *
00111     * When the parameter is a pointer to an integer array it will be the raw data.
00112     * When it is a pointer to a float array it will be the acceleration in g's
00113     *
00114     * @param data - pointer to array with length 3 where the acceleration data will be stored, X-Y-Z
00115     */
00116     void readData( int *data);
00117     void readData( float *data);
00118 
00119     /**
00120     * Get X-data
00121     *
00122     * @param return - X-acceleration in g's
00123     */
00124     float x( void );
00125 
00126     /**
00127     * Get Y-data
00128     *
00129     * @param return - Y-acceleration in g's
00130     */
00131     float y( void );
00132 
00133     /**
00134     * Get Z-data
00135     *
00136     * @param return - Z-acceleration in g's
00137     */
00138     float z( void );
00139 
00140     /**
00141     * Sets the active samplerate
00142     *
00143     * The entered samplerate will be rounded to nearest supported samplerate.
00144     * Supported samplerates are: 120 - 64 - 32 - 16 - 8 - 4 - 2 - 1 samples/second.
00145     *
00146     * @param samplerate - the samplerate that will be set
00147     */
00148     void setSampleRate(int samplerate);
00149 
00150     /**
00151     * Returns if it is on its front, back, or unknown side
00152     *
00153     * This is read from MMA7760s registers, page 12 of datasheet
00154     *
00155     * @param return - Front, Back or Unknown orientation
00156     */
00157     Orientation getSide( void );
00158 
00159     /**
00160     * Returns if it is on it left, right, down or up side
00161     *
00162     * This is read from MMA7760s registers, page 12 of datasheet
00163     *
00164     * @param return - Left, Right, Down, Up or Unknown orientation
00165     */
00166     Orientation getOrientation ( void );
00167 
00168 
00169 private:
00170 
00171     /**
00172     * Writes data to the device
00173     *
00174     * @param adress - register address to write to
00175     * @param data - data to write
00176     */
00177     void write( char address, char data);
00178 
00179     /**
00180     * Read data from the device
00181     *
00182     * @param adress - register address to write to
00183     * @return - data from the register specified by RA
00184     */
00185     char read( char adress);
00186 
00187     /**
00188      * Read multiple regigsters from the device, more efficient than using multiple normal reads.
00189      *
00190      * @param adress - register address to write to
00191      * @param length - number of bytes to read
00192      * @param data - pointer where the data needs to be written to
00193      */
00194     void read( char adress, char *data, int length);
00195 
00196     /**
00197     * Reads single axis
00198     */
00199     float getSingle(int number);
00200 
00201     I2C _i2c;
00202     bool active;
00203     float samplerate;
00204 };
00205 
00206 
00207 #endif