MPU6050.h

00001 /*Use #define MPU6050_ES before you include this file if you have an engineering sample (older EVBs will have them), to find out if you have one, check your accelerometer output. 
00002 If it is half of what you expected, and you still are on the correct planet, you got an engineering sample
00003 */
00004 
00005 
00006 #ifndef MPU6050_H
00007 #define MPU6050_H
00008 
00009 /**
00010  * Includes
00011  */
00012 #include "mbed.h"
00013 
00014 
00015 /**
00016  * Defines
00017  */
00018 #ifndef MPU6050_ADDRESS
00019     #define MPU6050_ADDRESS             0x68 // address pin low (GND), default for InvenSense evaluation board
00020 #endif
00021 
00022 #ifdef MPU6050_ES
00023         #define DOUBLE_ACCELERO
00024 #endif  
00025 
00026 /**
00027  * Registers
00028  */
00029  #define MPU6050_CONFIG_REG         0x1A
00030  #define MPU6050_GYRO_CONFIG_REG    0x1B
00031  #define MPU6050_ACCELERO_CONFIG_REG    0x1C
00032   
00033  #define MPU6050_INT_PIN_CFG        0x37
00034  
00035  #define MPU6050_ACCEL_XOUT_H_REG   0x3B
00036  #define MPU6050_ACCEL_YOUT_H_REG   0x3D
00037  #define MPU6050_ACCEL_ZOUT_H_REG   0x3F
00038  
00039  #define MPU6050_TEMP_H_REG         0x41
00040  
00041  #define MPU6050_GYRO_XOUT_H_REG    0x43
00042  #define MPU6050_GYRO_YOUT_H_REG    0x45
00043  #define MPU6050_GYRO_ZOUT_H_REG    0x47
00044  
00045  
00046  
00047  #define MPU6050_PWR_MGMT_1_REG     0x6B
00048  #define MPU6050_WHO_AM_I_REG       0x75
00049  
00050                  
00051  
00052  /**
00053   * Definitions
00054   */
00055 #define MPU6050_SLP_BIT             6
00056 #define MPU6050_BYPASS_BIT         1
00057 
00058 #define MPU6050_BW_256              0
00059 #define MPU6050_BW_188              1
00060 #define MPU6050_BW_98               2
00061 #define MPU6050_BW_42               3
00062 #define MPU6050_BW_20               4
00063 #define MPU6050_BW_10               5
00064 #define MPU6050_BW_5                6
00065 
00066 #define MPU6050_ACCELERO_RANGE_2G   0
00067 #define MPU6050_ACCELERO_RANGE_4G   1
00068 #define MPU6050_ACCELERO_RANGE_8G   2
00069 #define MPU6050_ACCELERO_RANGE_16G  3
00070 
00071 #define MPU6050_GYRO_RANGE_250      0
00072 #define MPU6050_GYRO_RANGE_500      1
00073 #define MPU6050_GYRO_RANGE_1000     2
00074 #define MPU6050_GYRO_RANGE_2000     3
00075 
00076 //interrupt address
00077 #define MPU6050_RA_INT_ENABLE 0x38  
00078 //define how the accelerometer is placed on surface
00079 #define X_AXIS 1
00080 #define Y_AXIS 2
00081 #define Z_AXIS 0
00082 //translation from radians to degrees
00083 #define RADIANS_TO_DEGREES 180/3.1415926536
00084 //constant used for the complementary filter, which ranges usually from 0.9 to 1.0
00085 #define ALPHA 0.96   //filter constant
00086 //scale the gyro
00087 #define GYRO_SCALE 2.7176 
00088 
00089 /** MPU6050 IMU library.
00090   *
00091   * Example:
00092   * @code
00093   * Later, maybe
00094   * @endcode
00095   */
00096 class MPU6050 {
00097     public:
00098      /**
00099      * Constructor.
00100      *
00101      * Sleep mode of MPU6050 is immediatly disabled
00102      *
00103      * @param sda - mbed pin to use for the SDA I2C line.
00104      * @param scl - mbed pin to use for the SCL I2C line.
00105      */
00106      MPU6050(PinName sda, PinName scl);
00107      
00108 
00109      /**
00110      * Tests the I2C connection by reading the WHO_AM_I register. 
00111      *
00112      * @return True for a working connection, false for an error
00113      */     
00114      bool testConnection( void );
00115      
00116      /**
00117      * Sets the bandwidth of the digital low-pass filter 
00118      *
00119      * Macros: MPU6050_BW_256 - MPU6050_BW_188 - MPU6050_BW_98 - MPU6050_BW_42 - MPU6050_BW_20 - MPU6050_BW_10 - MPU6050_BW_5
00120      * Last number is the gyro's BW in Hz (accelero BW is virtually identical)
00121      *
00122      * @param BW - The three bits that set the bandwidth (use the predefined macros)
00123      */     
00124      void setBW( char BW );
00125      
00126      /**
00127      * Sets the auxiliary I2C bus in bypass mode to read the sensors behind the MPU6050 (useful for eval board, otherwise just connect them to primary I2C bus) 
00128      *
00129      * @param state - Enables/disables the I2C bypass mode
00130      */     
00131      void setI2CBypass ( bool state );
00132      
00133      /**
00134      * Sets the Accelero full-scale range
00135      *
00136      * Macros: MPU6050_ACCELERO_RANGE_2G - MPU6050_ACCELERO_RANGE_4G - MPU6050_ACCELERO_RANGE_8G - MPU6050_ACCELERO_RANGE_16G
00137      *
00138      * @param range - The two bits that set the full-scale range (use the predefined macros)
00139      */
00140      void setAcceleroRange(char range);
00141      
00142      /**
00143      * Reads the accelero x-axis.
00144      *
00145      * @return 16-bit signed integer x-axis accelero data
00146      */   
00147      int getAcceleroRawX( void );
00148      
00149      /**
00150      * Reads the accelero y-axis.
00151      *
00152      * @return 16-bit signed integer y-axis accelero data
00153      */   
00154      int getAcceleroRawY( void );
00155      
00156      /**
00157      * Reads the accelero z-axis.
00158      *
00159      * @return 16-bit signed integer z-axis accelero data
00160      */   
00161      int getAcceleroRawZ( void );
00162      
00163      /**
00164      * Reads all accelero data.
00165      *
00166      * @param data - pointer to signed integer array with length three: data[0] = X, data[1] = Y, data[2] = Z
00167      */   
00168      void getAcceleroRaw( int *data );
00169      
00170      /**
00171      * Reads all accelero data, gives the acceleration in m/s2
00172      *
00173      * Function uses the last setup value of the full scale range, if you manually set in another range, this won't work.
00174      *
00175      * @param data - pointer to float array with length three: data[0] = X, data[1] = Y, data[2] = Z
00176      */   
00177      void getAccelero( float *data );
00178      
00179      /**
00180      * Sets the Gyro full-scale range
00181      *
00182      * Macros: MPU6050_GYRO_RANGE_250 - MPU6050_GYRO_RANGE_500 - MPU6050_GYRO_RANGE_1000 - MPU6050_GYRO_RANGE_2000
00183      *
00184      * @param range - The two bits that set the full-scale range (use the predefined macros)
00185      */
00186      void setGyroRange(char range);
00187 
00188      /**
00189      * Reads the gyro x-axis.
00190      *
00191      * @return 16-bit signed integer x-axis gyro data
00192      */   
00193      int getGyroRawX( void );
00194      
00195      /**
00196      * Reads the gyro y-axis.
00197      *
00198      * @return 16-bit signed integer y-axis gyro data
00199      */   
00200      int getGyroRawY( void );
00201      
00202      /**
00203      * Reads the gyro z-axis.
00204      *
00205      * @return 16-bit signed integer z-axis gyro data
00206      */   
00207      int getGyroRawZ( void );
00208      
00209      /**
00210      * Reads all gyro data.
00211      *
00212      * @param data - pointer to signed integer array with length three: data[0] = X, data[1] = Y, data[2] = Z
00213      */   
00214      void getGyroRaw( int *data );  
00215      
00216      /**
00217      * Reads all gyro data, gives the gyro in rad/s
00218      *
00219      * Function uses the last setup value of the full scale range, if you manually set in another range, this won't work.
00220      *
00221      * @param data - pointer to float array with length three: data[0] = X, data[1] = Y, data[2] = Z
00222      */   
00223      void getGyro( float *data);     
00224      
00225      /**
00226      * Reads temperature data.
00227      *
00228      * @return 16 bit signed integer with the raw temperature register value
00229      */  
00230      int getTempRaw( void );
00231      
00232      /**
00233      * Returns current temperature
00234      *
00235      * @returns float with the current temperature
00236      */  
00237      float getTemp( void );
00238 
00239      /**
00240      * Sets the sleep mode of the MPU6050 
00241      *
00242      * @param state - true for sleeping, false for wake up
00243      */     
00244      void setSleepMode( bool state );
00245      
00246      
00247      /**
00248      * Writes data to the device, could be private, but public is handy so you can transmit directly to the MPU. 
00249      *
00250      * @param adress - register address to write to
00251      * @param data - data to write
00252      */
00253      void write( char address, char data);
00254      
00255      /**
00256      * Read data from the device, could be private, but public is handy so you can transmit directly to the MPU. 
00257      *
00258      * @param adress - register address to write to
00259      * @return - data from the register specified by RA
00260      */
00261      char read( char adress);
00262      
00263      /**
00264      * Read multtiple regigsters from the device, more efficient than using multiple normal reads. 
00265      *
00266      * @param adress - register address to write to
00267      * @param length - number of bytes to read
00268      * @param data - pointer where the data needs to be written to 
00269      */
00270      void read( char adress, char *data, int length);
00271      
00272     /**
00273     * function for calculating the angle from the accelerometer.
00274     * it takes 3 values which correspond acceleration in X, Y and Z direction and calculates angles in degrees
00275     * for pitch, roll and one more direction.. (NOT YAW!)
00276     *
00277     * @param data - angle calculated using only accelerometer
00278     *
00279     */ 
00280     void getAcceleroAngle( float *data );
00281      
00282      
00283      /**function which allows to produce the offset values for gyro and accelerometer.
00284      * offset for gyro is simply a value, which needs to be substracted from original gyro rad/sec speed
00285      * but offset for accelerometer is calculated in angles... later on might change that
00286      * function simply takes the number of samples to be taken and calculated the average
00287      * 
00288      * @param accOffset - accelerometer offset in angle
00289      * @param gyroOffset - gyroscope offset in rad/s
00290      * @param sampleSize - number of samples to be taken for calculating offsets
00291      *
00292      */
00293      void getOffset(float *accOffset, float *gyroOffset, int sampleSize);
00294      
00295      /**
00296      * function for computing the angle, when accelerometer angle offset and gyro offset are both known.
00297      * we also need to know how much time passed from previous calculation to now
00298      * it produces the angle in degrees. However angles are produced from -90.0 to 90.0 degrees
00299      * if anyone need smth different, they can update this library...
00300      *
00301      * @param angle - calculated accurate angle from complemetary filter
00302      * @param accOffset - offset in angle for the accelerometer
00303      * @param gyroOffset - offset in rad/s for the gyroscope
00304      * @param interval - time before previous angle calculation and now
00305      *
00306      */
00307      void computeAngle (float *angle, float *accOffset, float *gyroOffset, float interval);
00308      
00309      ///function, which enables interrupts on MPU6050 INT pin
00310      void enableInt( void );
00311      
00312      ///disables interrupts
00313      void disableInt( void );
00314      
00315      /**function which sets the alpha value - constant for the complementary filter. default alpha = 0.97
00316      *
00317      * @param val - value the alpha (complementary filter constant) should be set to
00318      *
00319      */
00320      void setAlpha(float val);
00321      
00322      private:
00323 
00324      I2C connection;
00325      char currentAcceleroRange;
00326      char currentGyroRange;
00327      float alpha;   
00328      
00329 };
00330 
00331 
00332 
00333 #endif