MPU6050.h

00001 #ifndef MPU6050_H
00002 #define MPU6050_H
00003 
00004 #include "mbed.h"
00005 #include "math.h"
00006 
00007 // Define registers per MPU6050, Register Map and Descriptions, Rev 4.2, 08/19/2013 6 DOF Motion sensor fusion device
00008 // Invensense Inc., www.invensense.com
00009 // See also MPU-6050 Register Map and Descriptions, Revision 4.0, RM-MPU-6050A-00, 9/12/2012 for registers not listed in
00010 // above document; the MPU6050 and MPU 9150 are virtually identical but the latter has an on-board magnetic sensor
00011 //
00012 #define XGOFFS_TC        0x00 // Bit 7 PWR_MODE, bits 6:1 XG_OFFS_TC, bit 0 OTP_BNK_VLD                 
00013 #define YGOFFS_TC        0x01
00014 #define ZGOFFS_TC        0x02
00015 #define X_FINE_GAIN      0x03 // [7:0] fine gain
00016 #define Y_FINE_GAIN      0x04
00017 #define Z_FINE_GAIN      0x05
00018 #define XA_OFFSET_H      0x06 // User-defined trim values for accelerometer
00019 #define XA_OFFSET_L_TC   0x07
00020 #define YA_OFFSET_H      0x08
00021 #define YA_OFFSET_L_TC   0x09
00022 #define ZA_OFFSET_H      0x0A
00023 #define ZA_OFFSET_L_TC   0x0B
00024 #define SELF_TEST_X      0x0D
00025 #define SELF_TEST_Y      0x0E
00026 #define SELF_TEST_Z      0x0F
00027 #define SELF_TEST_A      0x10
00028 #define XG_OFFS_USRH     0x13  // User-defined trim values for gyroscope; supported in MPU-6050?
00029 #define XG_OFFS_USRL     0x14
00030 #define YG_OFFS_USRH     0x15
00031 #define YG_OFFS_USRL     0x16
00032 #define ZG_OFFS_USRH     0x17
00033 #define ZG_OFFS_USRL     0x18
00034 #define SMPLRT_DIV       0x19
00035 #define CONFIG           0x1A
00036 #define GYRO_CONFIG      0x1B
00037 #define ACCEL_CONFIG     0x1C
00038 #define FF_THR           0x1D  // Free-fall
00039 #define FF_DUR           0x1E  // Free-fall
00040 #define MOT_THR          0x1F  // Motion detection threshold bits [7:0]
00041 #define MOT_DUR          0x20  // Duration counter threshold for motion interrupt generation, 1 kHz rate, LSB = 1 ms
00042 #define ZMOT_THR         0x21  // Zero-motion detection threshold bits [7:0]
00043 #define ZRMOT_DUR        0x22  // Duration counter threshold for zero motion interrupt generation, 16 Hz rate, LSB = 64 ms
00044 #define FIFO_EN          0x23
00045 #define I2C_MST_CTRL     0x24
00046 #define I2C_SLV0_ADDR    0x25
00047 #define I2C_SLV0_REG     0x26
00048 #define I2C_SLV0_CTRL    0x27
00049 #define I2C_SLV1_ADDR    0x28
00050 #define I2C_SLV1_REG     0x29
00051 #define I2C_SLV1_CTRL    0x2A
00052 #define I2C_SLV2_ADDR    0x2B
00053 #define I2C_SLV2_REG     0x2C
00054 #define I2C_SLV2_CTRL    0x2D
00055 #define I2C_SLV3_ADDR    0x2E
00056 #define I2C_SLV3_REG     0x2F
00057 #define I2C_SLV3_CTRL    0x30
00058 #define I2C_SLV4_ADDR    0x31
00059 #define I2C_SLV4_REG     0x32
00060 #define I2C_SLV4_DO      0x33
00061 #define I2C_SLV4_CTRL    0x34
00062 #define I2C_SLV4_DI      0x35
00063 #define I2C_MST_STATUS   0x36
00064 #define INT_PIN_CFG      0x37
00065 #define INT_ENABLE       0x38
00066 #define DMP_INT_STATUS   0x39  // Check DMP interrupt
00067 #define INT_STATUS       0x3A
00068 #define ACCEL_XOUT_H     0x3B
00069 #define ACCEL_XOUT_L     0x3C
00070 #define ACCEL_YOUT_H     0x3D
00071 #define ACCEL_YOUT_L     0x3E
00072 #define ACCEL_ZOUT_H     0x3F
00073 #define ACCEL_ZOUT_L     0x40
00074 #define TEMP_OUT_H       0x41
00075 #define TEMP_OUT_L       0x42
00076 #define GYRO_XOUT_H      0x43
00077 #define GYRO_XOUT_L      0x44
00078 #define GYRO_YOUT_H      0x45
00079 #define GYRO_YOUT_L      0x46
00080 #define GYRO_ZOUT_H      0x47
00081 #define GYRO_ZOUT_L      0x48
00082 #define EXT_SENS_DATA_00 0x49
00083 #define EXT_SENS_DATA_01 0x4A
00084 #define EXT_SENS_DATA_02 0x4B
00085 #define EXT_SENS_DATA_03 0x4C
00086 #define EXT_SENS_DATA_04 0x4D
00087 #define EXT_SENS_DATA_05 0x4E
00088 #define EXT_SENS_DATA_06 0x4F
00089 #define EXT_SENS_DATA_07 0x50
00090 #define EXT_SENS_DATA_08 0x51
00091 #define EXT_SENS_DATA_09 0x52
00092 #define EXT_SENS_DATA_10 0x53
00093 #define EXT_SENS_DATA_11 0x54
00094 #define EXT_SENS_DATA_12 0x55
00095 #define EXT_SENS_DATA_13 0x56
00096 #define EXT_SENS_DATA_14 0x57
00097 #define EXT_SENS_DATA_15 0x58
00098 #define EXT_SENS_DATA_16 0x59
00099 #define EXT_SENS_DATA_17 0x5A
00100 #define EXT_SENS_DATA_18 0x5B
00101 #define EXT_SENS_DATA_19 0x5C
00102 #define EXT_SENS_DATA_20 0x5D
00103 #define EXT_SENS_DATA_21 0x5E
00104 #define EXT_SENS_DATA_22 0x5F
00105 #define EXT_SENS_DATA_23 0x60
00106 #define MOT_DETECT_STATUS 0x61
00107 #define I2C_SLV0_DO      0x63
00108 #define I2C_SLV1_DO      0x64
00109 #define I2C_SLV2_DO      0x65
00110 #define I2C_SLV3_DO      0x66
00111 #define I2C_MST_DELAY_CTRL 0x67
00112 #define SIGNAL_PATH_RESET  0x68
00113 #define MOT_DETECT_CTRL   0x69
00114 #define USER_CTRL        0x6A  // Bit 7 enable DMP, bit 3 reset DMP
00115 #define PWR_MGMT_1       0x6B // Device defaults to the SLEEP mode
00116 #define PWR_MGMT_2       0x6C
00117 #define DMP_BANK         0x6D  // Activates a specific bank in the DMP
00118 #define DMP_RW_PNT       0x6E  // Set read/write pointer to a specific start address in specified DMP bank
00119 #define DMP_REG          0x6F  // Register in DMP from which to read or to which to write
00120 #define DMP_REG_1        0x70
00121 #define DMP_REG_2        0x71
00122 #define FIFO_COUNTH      0x72
00123 #define FIFO_COUNTL      0x73
00124 #define FIFO_R_W         0x74
00125 #define WHO_AM_I_MPU6050 0x75 // Should return 0x68
00126 
00127 // Using the GY-521 breakout board, I set ADO to 0 by grounding through a 4k7 resistor
00128 // Seven-bit device address is 110100 for ADO = 0 and 110101 for ADO = 1
00129 #define ADO 0
00130 #if ADO
00131 #define MPU6050_ADDRESS 0x69<<1  // Device address when ADO = 1
00132 #else
00133 #define MPU6050_ADDRESS 0x68<<1  // Device address when ADO = 0
00134 #endif
00135 
00136 // Set initial input parameters
00137 enum Ascale {
00138     AFS_2G = 0,
00139     AFS_4G,
00140     AFS_8G,
00141     AFS_16G
00142 };
00143 
00144 enum Gscale {
00145     GFS_250DPS = 0,
00146     GFS_500DPS,
00147     GFS_1000DPS,
00148     GFS_2000DPS
00149 };
00150 
00151 // Specify sensor full scale
00152 int Gscale = GFS_250DPS;
00153 int Ascale = AFS_2G;
00154 
00155 //Set up I2C, (SDA,SCL)
00156 I2C i2c(I2C_SDA, I2C_SCL);
00157 
00158 float aRes, gRes; // scale resolutions per LSB for the sensors
00159 
00160 // Pin definitions
00161 int intPin = 12;  // These can be changed, 2 and 3 are the Arduinos ext int pins
00162 
00163 int16_t accelCount[3];  // Stores the 16-bit signed accelerometer sensor output
00164 float ax, ay, az;       // Stores the real accel value in g's
00165 int16_t gyroCount[3];   // Stores the 16-bit signed gyro sensor output
00166 float gx, gy, gz;       // Stores the real gyro value in degrees per seconds
00167 float gyroBias[3] = {0, 0, 0}, accelBias[3] = {0, 0, 0}; // Bias corrections for gyro and accelerometer
00168 int16_t tempCount;   // Stores the real internal chip temperature in degrees Celsius
00169 float temperature;
00170 float SelfTest[6];
00171 
00172 int delt_t = 0; // used to control display output rate
00173 int count = 0;  // used to control display output rate
00174 
00175 // parameters for 6 DoF sensor fusion calculations
00176 float PI = 3.14159265358979323846f;
00177 float GyroMeasError = PI * (60.0f / 180.0f);     // gyroscope measurement error in rads/s (start at 60 deg/s), then reduce after ~10 s to 3
00178 float beta = sqrt(3.0f / 4.0f) * GyroMeasError;  // compute beta
00179 float GyroMeasDrift = PI * (1.0f / 180.0f);      // gyroscope measurement drift in rad/s/s (start at 0.0 deg/s/s)
00180 float zeta = sqrt(3.0f / 4.0f) * GyroMeasDrift;  // compute zeta, the other free parameter in the Madgwick scheme usually set to a small or zero value
00181 float pitch, yaw, roll;
00182 float deltat = 0.0f;                              // integration interval for both filter schemes
00183 int lastUpdate = 0, firstUpdate = 0, Now = 0;     // used to calculate integration interval                               // used to calculate integration interval
00184 float q[4] = {1.0f, 0.0f, 0.0f, 0.0f};            // vector to hold quaternion
00185 
00186 class MPU6050
00187 {
00188 
00189 protected:
00190 
00191 public:
00192     //===================================================================================================================
00193 //====== Set of useful function to access acceleratio, gyroscope, and temperature data
00194 //===================================================================================================================
00195 
00196     void writeByte(uint8_t address, uint8_t subAddress, uint8_t data) {
00197         char data_write[2];
00198         data_write[0] = subAddress;
00199         data_write[1] = data;
00200         i2c.write(address, data_write, 2, 0);
00201     }
00202 
00203     char readByte(uint8_t address, uint8_t subAddress) {
00204         char data[1]; // `data` will store the register data
00205         char data_write[1];
00206         data_write[0] = subAddress;
00207         i2c.write(address, data_write, 1, 1); // no stop
00208         i2c.read(address, data, 1, 0);
00209         return data[0];
00210     }
00211 
00212     void readBytes(uint8_t address, uint8_t subAddress, uint8_t count, uint8_t * dest) {
00213         char data[14];
00214         char data_write[1];
00215         data_write[0] = subAddress;
00216         i2c.write(address, data_write, 1, 1); // no stop
00217         i2c.read(address, data, count, 0);
00218         for(int ii = 0; ii < count; ii++) {
00219             dest[ii] = data[ii];
00220         }
00221     }
00222 
00223 
00224     void getGres() {
00225         switch (Gscale) {
00226                 // Possible gyro scales (and their register bit settings) are:
00227                 // 250 DPS (00), 500 DPS (01), 1000 DPS (10), and 2000 DPS  (11).
00228                 // Here's a bit of an algorith to calculate DPS/(ADC tick) based on that 2-bit value:
00229             case GFS_250DPS:
00230                 gRes = 250.0/32768.0;
00231                 break;
00232             case GFS_500DPS:
00233                 gRes = 500.0/32768.0;
00234                 break;
00235             case GFS_1000DPS:
00236                 gRes = 1000.0/32768.0;
00237                 break;
00238             case GFS_2000DPS:
00239                 gRes = 2000.0/32768.0;
00240                 break;
00241         }
00242     }
00243 
00244     void getAres() {
00245         switch (Ascale) {
00246                 // Possible accelerometer scales (and their register bit settings) are:
00247                 // 2 Gs (00), 4 Gs (01), 8 Gs (10), and 16 Gs  (11).
00248                 // Here's a bit of an algorith to calculate DPS/(ADC tick) based on that 2-bit value:
00249             case AFS_2G:
00250                 aRes = 2.0/32768.0;
00251                 break;
00252             case AFS_4G:
00253                 aRes = 4.0/32768.0;
00254                 break;
00255             case AFS_8G:
00256                 aRes = 8.0/32768.0;
00257                 break;
00258             case AFS_16G:
00259                 aRes = 16.0/32768.0;
00260                 break;
00261         }
00262     }
00263 
00264 
00265     void readAccelData(int16_t * destination) {
00266         uint8_t rawData[6];  // x/y/z accel register data stored here
00267         readBytes(MPU6050_ADDRESS, ACCEL_XOUT_H, 6, &rawData[0]);  // Read the six raw data registers into data array
00268         destination[0] = (int16_t)(((int16_t)rawData[0] << 8) | rawData[1]) ;  // Turn the MSB and LSB into a signed 16-bit value
00269         destination[1] = (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ;
00270         destination[2] = (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ;
00271     }
00272 
00273     void readGyroData(int16_t * destination) {
00274         uint8_t rawData[6];  // x/y/z gyro register data stored here
00275         readBytes(MPU6050_ADDRESS, GYRO_XOUT_H, 6, &rawData[0]);  // Read the six raw data registers sequentially into data array
00276         destination[0] = (int16_t)(((int16_t)rawData[0] << 8) | rawData[1]) ;  // Turn the MSB and LSB into a signed 16-bit value
00277         destination[1] = (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ;
00278         destination[2] = (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ;
00279     }
00280 
00281     int16_t readTempData() {
00282         uint8_t rawData[2];  // x/y/z gyro register data stored here
00283         readBytes(MPU6050_ADDRESS, TEMP_OUT_H, 2, &rawData[0]);  // Read the two raw data registers sequentially into data array
00284         return (int16_t)(((int16_t)rawData[0]) << 8 | rawData[1]) ;  // Turn the MSB and LSB into a 16-bit value
00285     }
00286 
00287 
00288 
00289 // Configure the motion detection control for low power accelerometer mode
00290     void LowPowerAccelOnly() {
00291 
00292 // The sensor has a high-pass filter necessary to invoke to allow the sensor motion detection algorithms work properly
00293 // Motion detection occurs on free-fall (acceleration below a threshold for some time for all axes), motion (acceleration
00294 // above a threshold for some time on at least one axis), and zero-motion toggle (acceleration on each axis less than a
00295 // threshold for some time sets this flag, motion above the threshold turns it off). The high-pass filter takes gravity out
00296 // consideration for these threshold evaluations; otherwise, the flags would be set all the time!
00297 
00298         uint8_t c = readByte(MPU6050_ADDRESS, PWR_MGMT_1);
00299         writeByte(MPU6050_ADDRESS, PWR_MGMT_1, c & ~0x30); // Clear sleep and cycle bits [5:6]
00300         writeByte(MPU6050_ADDRESS, PWR_MGMT_1, c |  0x30); // Set sleep and cycle bits [5:6] to zero to make sure accelerometer is running
00301 
00302         c = readByte(MPU6050_ADDRESS, PWR_MGMT_2);
00303         writeByte(MPU6050_ADDRESS, PWR_MGMT_2, c & ~0x38); // Clear standby XA, YA, and ZA bits [3:5]
00304         writeByte(MPU6050_ADDRESS, PWR_MGMT_2, c |  0x00); // Set XA, YA, and ZA bits [3:5] to zero to make sure accelerometer is running
00305 
00306         c = readByte(MPU6050_ADDRESS, ACCEL_CONFIG);
00307         writeByte(MPU6050_ADDRESS, ACCEL_CONFIG, c & ~0x07); // Clear high-pass filter bits [2:0]
00308 // Set high-pass filter to 0) reset (disable), 1) 5 Hz, 2) 2.5 Hz, 3) 1.25 Hz, 4) 0.63 Hz, or 7) Hold
00309         writeByte(MPU6050_ADDRESS, ACCEL_CONFIG,  c | 0x00);  // Set ACCEL_HPF to 0; reset mode disbaling high-pass filter
00310 
00311         c = readByte(MPU6050_ADDRESS, CONFIG);
00312         writeByte(MPU6050_ADDRESS, CONFIG, c & ~0x07); // Clear low-pass filter bits [2:0]
00313         writeByte(MPU6050_ADDRESS, CONFIG, c |  0x00);  // Set DLPD_CFG to 0; 260 Hz bandwidth, 1 kHz rate
00314 
00315         c = readByte(MPU6050_ADDRESS, INT_ENABLE);
00316         writeByte(MPU6050_ADDRESS, INT_ENABLE, c & ~0xFF);  // Clear all interrupts
00317         writeByte(MPU6050_ADDRESS, INT_ENABLE, 0x40);  // Enable motion threshold (bits 5) interrupt only
00318 
00319 // Motion detection interrupt requires the absolute value of any axis to lie above the detection threshold
00320 // for at least the counter duration
00321         writeByte(MPU6050_ADDRESS, MOT_THR, 0x80); // Set motion detection to 0.256 g; LSB = 2 mg
00322         writeByte(MPU6050_ADDRESS, MOT_DUR, 0x01); // Set motion detect duration to 1  ms; LSB is 1 ms @ 1 kHz rate
00323 
00324         wait(0.1);  // Add delay for accumulation of samples
00325 
00326         c = readByte(MPU6050_ADDRESS, ACCEL_CONFIG);
00327         writeByte(MPU6050_ADDRESS, ACCEL_CONFIG, c & ~0x07); // Clear high-pass filter bits [2:0]
00328         writeByte(MPU6050_ADDRESS, ACCEL_CONFIG, c |  0x07);  // Set ACCEL_HPF to 7; hold the initial accleration value as a referance
00329 
00330         c = readByte(MPU6050_ADDRESS, PWR_MGMT_2);
00331         writeByte(MPU6050_ADDRESS, PWR_MGMT_2, c & ~0xC7); // Clear standby XA, YA, and ZA bits [3:5] and LP_WAKE_CTRL bits [6:7]
00332         writeByte(MPU6050_ADDRESS, PWR_MGMT_2, c |  0x47); // Set wakeup frequency to 5 Hz, and disable XG, YG, and ZG gyros (bits [0:2])
00333 
00334         c = readByte(MPU6050_ADDRESS, PWR_MGMT_1);
00335         writeByte(MPU6050_ADDRESS, PWR_MGMT_1, c & ~0x20); // Clear sleep and cycle bit 5
00336         writeByte(MPU6050_ADDRESS, PWR_MGMT_1, c |  0x20); // Set cycle bit 5 to begin low power accelerometer motion interrupts
00337 
00338     }
00339 
00340 
00341     void resetMPU6050() {
00342         // reset device
00343         writeByte(MPU6050_ADDRESS, PWR_MGMT_1, 0x80); // Write a one to bit 7 reset bit; toggle reset device
00344         wait(0.1);
00345     }
00346 
00347 
00348     void initMPU6050() {
00349 // Initialize MPU6050 device
00350 // wake up device
00351         writeByte(MPU6050_ADDRESS, PWR_MGMT_1, 0x00); // Clear sleep mode bit (6), enable all sensors
00352         wait(0.1); // Delay 100 ms for PLL to get established on x-axis gyro; should check for PLL ready interrupt
00353 
00354 // get stable time source
00355         writeByte(MPU6050_ADDRESS, PWR_MGMT_1, 0x01);  // Set clock source to be PLL with x-axis gyroscope reference, bits 2:0 = 001
00356 
00357 // Configure Gyro and Accelerometer
00358 // Disable FSYNC and set accelerometer and gyro bandwidth to 44 and 42 Hz, respectively;
00359 // DLPF_CFG = bits 2:0 = 010; this sets the sample rate at 1 kHz for both
00360 // Maximum delay is 4.9 ms which is just over a 200 Hz maximum rate
00361         writeByte(MPU6050_ADDRESS, CONFIG, 0x03);
00362 
00363 // Set sample rate = gyroscope output rate/(1 + SMPLRT_DIV)
00364         writeByte(MPU6050_ADDRESS, SMPLRT_DIV, 0x04);  // Use a 200 Hz rate; the same rate set in CONFIG above
00365 
00366 // Set gyroscope full scale range
00367 // Range selects FS_SEL and AFS_SEL are 0 - 3, so 2-bit values are left-shifted into positions 4:3
00368         uint8_t c =  readByte(MPU6050_ADDRESS, GYRO_CONFIG);
00369         writeByte(MPU6050_ADDRESS, GYRO_CONFIG, c & ~0xE0); // Clear self-test bits [7:5]
00370         writeByte(MPU6050_ADDRESS, GYRO_CONFIG, c & ~0x18); // Clear AFS bits [4:3]
00371         writeByte(MPU6050_ADDRESS, GYRO_CONFIG, c | Gscale << 3); // Set full scale range for the gyro
00372 
00373 // Set accelerometer configuration
00374         c =  readByte(MPU6050_ADDRESS, ACCEL_CONFIG);
00375         writeByte(MPU6050_ADDRESS, ACCEL_CONFIG, c & ~0xE0); // Clear self-test bits [7:5]
00376         writeByte(MPU6050_ADDRESS, ACCEL_CONFIG, c & ~0x18); // Clear AFS bits [4:3]
00377         writeByte(MPU6050_ADDRESS, ACCEL_CONFIG, c | Ascale << 3); // Set full scale range for the accelerometer
00378 
00379         // Configure Interrupts and Bypass Enable
00380         // Set interrupt pin active high, push-pull, and clear on read of INT_STATUS, enable I2C_BYPASS_EN so additional chips
00381         // can join the I2C bus and all can be controlled by the Arduino as master
00382         writeByte(MPU6050_ADDRESS, INT_PIN_CFG, 0x22);
00383         writeByte(MPU6050_ADDRESS, INT_ENABLE, 0x01);  // Enable data ready (bit 0) interrupt
00384     }
00385 
00386 // Function which accumulates gyro and accelerometer data after device initialization. It calculates the average
00387 // of the at-rest readings and then loads the resulting offsets into accelerometer and gyro bias registers.
00388     void calibrateMPU6050(float * dest1, float * dest2) {
00389         uint8_t data[12]; // data array to hold accelerometer and gyro x, y, z, data
00390         uint16_t ii, packet_count, fifo_count;
00391         int32_t gyro_bias[3] = {0, 0, 0}, accel_bias[3] = {0, 0, 0};
00392 
00393 // reset device, reset all registers, clear gyro and accelerometer bias registers
00394         writeByte(MPU6050_ADDRESS, PWR_MGMT_1, 0x80); // Write a one to bit 7 reset bit; toggle reset device
00395         wait(0.1);
00396 
00397 // get stable time source
00398 // Set clock source to be PLL with x-axis gyroscope reference, bits 2:0 = 001
00399         writeByte(MPU6050_ADDRESS, PWR_MGMT_1, 0x01);
00400         writeByte(MPU6050_ADDRESS, PWR_MGMT_2, 0x00);
00401         wait(0.2);
00402 
00403 // Configure device for bias calculation
00404         writeByte(MPU6050_ADDRESS, INT_ENABLE, 0x00);   // Disable all interrupts
00405         writeByte(MPU6050_ADDRESS, FIFO_EN, 0x00);      // Disable FIFO
00406         writeByte(MPU6050_ADDRESS, PWR_MGMT_1, 0x00);   // Turn on internal clock source
00407         writeByte(MPU6050_ADDRESS, I2C_MST_CTRL, 0x00); // Disable I2C master
00408         writeByte(MPU6050_ADDRESS, USER_CTRL, 0x00);    // Disable FIFO and I2C master modes
00409         writeByte(MPU6050_ADDRESS, USER_CTRL, 0x0C);    // Reset FIFO and DMP
00410         wait(0.015);
00411 
00412 // Configure MPU6050 gyro and accelerometer for bias calculation
00413         writeByte(MPU6050_ADDRESS, CONFIG, 0x01);      // Set low-pass filter to 188 Hz
00414         writeByte(MPU6050_ADDRESS, SMPLRT_DIV, 0x00);  // Set sample rate to 1 kHz
00415         writeByte(MPU6050_ADDRESS, GYRO_CONFIG, 0x00);  // Set gyro full-scale to 250 degrees per second, maximum sensitivity
00416         writeByte(MPU6050_ADDRESS, ACCEL_CONFIG, 0x00); // Set accelerometer full-scale to 2 g, maximum sensitivity
00417 
00418         uint16_t  gyrosensitivity  = 131;   // = 131 LSB/degrees/sec
00419         uint16_t  accelsensitivity = 16384;  // = 16384 LSB/g
00420 
00421 // Configure FIFO to capture accelerometer and gyro data for bias calculation
00422         writeByte(MPU6050_ADDRESS, USER_CTRL, 0x40);   // Enable FIFO
00423         writeByte(MPU6050_ADDRESS, FIFO_EN, 0x78);     // Enable gyro and accelerometer sensors for FIFO  (max size 1024 bytes in MPU-6050)
00424         wait(0.08); // accumulate 80 samples in 80 milliseconds = 960 bytes
00425 
00426 // At end of sample accumulation, turn off FIFO sensor read
00427         writeByte(MPU6050_ADDRESS, FIFO_EN, 0x00);        // Disable gyro and accelerometer sensors for FIFO
00428         readBytes(MPU6050_ADDRESS, FIFO_COUNTH, 2, &data[0]); // read FIFO sample count
00429         fifo_count = ((uint16_t)data[0] << 8) | data[1];
00430         packet_count = fifo_count/12;// How many sets of full gyro and accelerometer data for averaging
00431 
00432         for (ii = 0; ii < packet_count; ii++) {
00433             int16_t accel_temp[3] = {0, 0, 0}, gyro_temp[3] = {0, 0, 0};
00434             readBytes(MPU6050_ADDRESS, FIFO_R_W, 12, &data[0]); // read data for averaging
00435             accel_temp[0] = (int16_t) (((int16_t)data[0] << 8) | data[1]  ) ;  // Form signed 16-bit integer for each sample in FIFO
00436             accel_temp[1] = (int16_t) (((int16_t)data[2] << 8) | data[3]  ) ;
00437             accel_temp[2] = (int16_t) (((int16_t)data[4] << 8) | data[5]  ) ;
00438             gyro_temp[0]  = (int16_t) (((int16_t)data[6] << 8) | data[7]  ) ;
00439             gyro_temp[1]  = (int16_t) (((int16_t)data[8] << 8) | data[9]  ) ;
00440             gyro_temp[2]  = (int16_t) (((int16_t)data[10] << 8) | data[11]) ;
00441 
00442             accel_bias[0] += (int32_t) accel_temp[0]; // Sum individual signed 16-bit biases to get accumulated signed 32-bit biases
00443             accel_bias[1] += (int32_t) accel_temp[1];
00444             accel_bias[2] += (int32_t) accel_temp[2];
00445             gyro_bias[0]  += (int32_t) gyro_temp[0];
00446             gyro_bias[1]  += (int32_t) gyro_temp[1];
00447             gyro_bias[2]  += (int32_t) gyro_temp[2];
00448 
00449         }
00450         accel_bias[0] /= (int32_t) packet_count; // Normalize sums to get average count biases
00451         accel_bias[1] /= (int32_t) packet_count;
00452         accel_bias[2] /= (int32_t) packet_count;
00453         gyro_bias[0]  /= (int32_t) packet_count;
00454         gyro_bias[1]  /= (int32_t) packet_count;
00455         gyro_bias[2]  /= (int32_t) packet_count;
00456 
00457         if(accel_bias[2] > 0L) {
00458             accel_bias[2] -= (int32_t) accelsensitivity;   // Remove gravity from the z-axis accelerometer bias calculation
00459         } else {
00460             accel_bias[2] += (int32_t) accelsensitivity;
00461         }
00462 
00463 // Construct the gyro biases for push to the hardware gyro bias registers, which are reset to zero upon device startup
00464         data[0] = (-gyro_bias[0]/4  >> 8) & 0xFF; // Divide by 4 to get 32.9 LSB per deg/s to conform to expected bias input format
00465         data[1] = (-gyro_bias[0]/4)       & 0xFF; // Biases are additive, so change sign on calculated average gyro biases
00466         data[2] = (-gyro_bias[1]/4  >> 8) & 0xFF;
00467         data[3] = (-gyro_bias[1]/4)       & 0xFF;
00468         data[4] = (-gyro_bias[2]/4  >> 8) & 0xFF;
00469         data[5] = (-gyro_bias[2]/4)       & 0xFF;
00470 
00471 // Push gyro biases to hardware registers
00472         writeByte(MPU6050_ADDRESS, XG_OFFS_USRH, data[0]);
00473         writeByte(MPU6050_ADDRESS, XG_OFFS_USRL, data[1]);
00474         writeByte(MPU6050_ADDRESS, YG_OFFS_USRH, data[2]);
00475         writeByte(MPU6050_ADDRESS, YG_OFFS_USRL, data[3]);
00476         writeByte(MPU6050_ADDRESS, ZG_OFFS_USRH, data[4]);
00477         writeByte(MPU6050_ADDRESS, ZG_OFFS_USRL, data[5]);
00478 
00479         dest1[0] = (float) gyro_bias[0]/(float) gyrosensitivity; // construct gyro bias in deg/s for later manual subtraction
00480         dest1[1] = (float) gyro_bias[1]/(float) gyrosensitivity;
00481         dest1[2] = (float) gyro_bias[2]/(float) gyrosensitivity;
00482 
00483 // Construct the accelerometer biases for push to the hardware accelerometer bias registers. These registers contain
00484 // factory trim values which must be added to the calculated accelerometer biases; on boot up these registers will hold
00485 // non-zero values. In addition, bit 0 of the lower byte must be preserved since it is used for temperature
00486 // compensation calculations. Accelerometer bias registers expect bias input as 2048 LSB per g, so that
00487 // the accelerometer biases calculated above must be divided by 8.
00488 
00489         int32_t accel_bias_reg[3] = {0, 0, 0}; // A place to hold the factory accelerometer trim biases
00490         readBytes(MPU6050_ADDRESS, XA_OFFSET_H, 2, &data[0]); // Read factory accelerometer trim values
00491         accel_bias_reg[0] = (int16_t) ((int16_t)data[0] << 8) | data[1];
00492         readBytes(MPU6050_ADDRESS, YA_OFFSET_H, 2, &data[0]);
00493         accel_bias_reg[1] = (int16_t) ((int16_t)data[0] << 8) | data[1];
00494         readBytes(MPU6050_ADDRESS, ZA_OFFSET_H, 2, &data[0]);
00495         accel_bias_reg[2] = (int16_t) ((int16_t)data[0] << 8) | data[1];
00496 
00497         uint32_t mask = 1uL; // Define mask for temperature compensation bit 0 of lower byte of accelerometer bias registers
00498         uint8_t mask_bit[3] = {0, 0, 0}; // Define array to hold mask bit for each accelerometer bias axis
00499 
00500         for(ii = 0; ii < 3; ii++) {
00501             if(accel_bias_reg[ii] & mask) mask_bit[ii] = 0x01; // If temperature compensation bit is set, record that fact in mask_bit
00502         }
00503 
00504         // Construct total accelerometer bias, including calculated average accelerometer bias from above
00505         accel_bias_reg[0] -= (accel_bias[0]/8); // Subtract calculated averaged accelerometer bias scaled to 2048 LSB/g (16 g full scale)
00506         accel_bias_reg[1] -= (accel_bias[1]/8);
00507         accel_bias_reg[2] -= (accel_bias[2]/8);
00508 
00509         data[0] = (accel_bias_reg[0] >> 8) & 0xFF;
00510         data[1] = (accel_bias_reg[0])      & 0xFF;
00511         data[1] = data[1] | mask_bit[0]; // preserve temperature compensation bit when writing back to accelerometer bias registers
00512         data[2] = (accel_bias_reg[1] >> 8) & 0xFF;
00513         data[3] = (accel_bias_reg[1])      & 0xFF;
00514         data[3] = data[3] | mask_bit[1]; // preserve temperature compensation bit when writing back to accelerometer bias registers
00515         data[4] = (accel_bias_reg[2] >> 8) & 0xFF;
00516         data[5] = (accel_bias_reg[2])      & 0xFF;
00517         data[5] = data[5] | mask_bit[2]; // preserve temperature compensation bit when writing back to accelerometer bias registers
00518 
00519         // Push accelerometer biases to hardware registers
00520 //  writeByte(MPU6050_ADDRESS, XA_OFFSET_H, data[0]);
00521 //  writeByte(MPU6050_ADDRESS, XA_OFFSET_L_TC, data[1]);
00522 //  writeByte(MPU6050_ADDRESS, YA_OFFSET_H, data[2]);
00523 //  writeByte(MPU6050_ADDRESS, YA_OFFSET_L_TC, data[3]);
00524 //  writeByte(MPU6050_ADDRESS, ZA_OFFSET_H, data[4]);
00525 //  writeByte(MPU6050_ADDRESS, ZA_OFFSET_L_TC, data[5]);
00526 
00527 // Output scaled accelerometer biases for manual subtraction in the main program
00528         dest2[0] = (float)accel_bias[0]/(float)accelsensitivity;
00529         dest2[1] = (float)accel_bias[1]/(float)accelsensitivity;
00530         dest2[2] = (float)accel_bias[2]/(float)accelsensitivity;
00531     }
00532 
00533 
00534 // Accelerometer and gyroscope self test; check calibration wrt factory settings
00535     void MPU6050SelfTest(float * destination) { // Should return percent deviation from factory trim values, +/- 14 or less deviation is a pass
00536         uint8_t rawData[4] = {0, 0, 0, 0};
00537         uint8_t selfTest[6];
00538         float factoryTrim[6];
00539 
00540         // Configure the accelerometer for self-test
00541         writeByte(MPU6050_ADDRESS, ACCEL_CONFIG, 0xF0); // Enable self test on all three axes and set accelerometer range to +/- 8 g
00542         writeByte(MPU6050_ADDRESS, GYRO_CONFIG,  0xE0); // Enable self test on all three axes and set gyro range to +/- 250 degrees/s
00543         wait(0.25);  // Delay a while to let the device execute the self-test
00544         rawData[0] = readByte(MPU6050_ADDRESS, SELF_TEST_X); // X-axis self-test results
00545         rawData[1] = readByte(MPU6050_ADDRESS, SELF_TEST_Y); // Y-axis self-test results
00546         rawData[2] = readByte(MPU6050_ADDRESS, SELF_TEST_Z); // Z-axis self-test results
00547         rawData[3] = readByte(MPU6050_ADDRESS, SELF_TEST_A); // Mixed-axis self-test results
00548         // Extract the acceleration test results first
00549         selfTest[0] = (rawData[0] >> 3) | (rawData[3] & 0x30) >> 4 ; // XA_TEST result is a five-bit unsigned integer
00550         selfTest[1] = (rawData[1] >> 3) | (rawData[3] & 0x0C) >> 4 ; // YA_TEST result is a five-bit unsigned integer
00551         selfTest[2] = (rawData[2] >> 3) | (rawData[3] & 0x03) >> 4 ; // ZA_TEST result is a five-bit unsigned integer
00552         // Extract the gyration test results first
00553         selfTest[3] = rawData[0]  & 0x1F ; // XG_TEST result is a five-bit unsigned integer
00554         selfTest[4] = rawData[1]  & 0x1F ; // YG_TEST result is a five-bit unsigned integer
00555         selfTest[5] = rawData[2]  & 0x1F ; // ZG_TEST result is a five-bit unsigned integer
00556         // Process results to allow final comparison with factory set values
00557         factoryTrim[0] = (4096.0f*0.34f)*(pow( (0.92f/0.34f) , ((selfTest[0] - 1.0f)/30.0f))); // FT[Xa] factory trim calculation
00558         factoryTrim[1] = (4096.0f*0.34f)*(pow( (0.92f/0.34f) , ((selfTest[1] - 1.0f)/30.0f))); // FT[Ya] factory trim calculation
00559         factoryTrim[2] = (4096.0f*0.34f)*(pow( (0.92f/0.34f) , ((selfTest[2] - 1.0f)/30.0f))); // FT[Za] factory trim calculation
00560         factoryTrim[3] =  ( 25.0f*131.0f)*(pow( 1.046f , (selfTest[3] - 1.0f) ));             // FT[Xg] factory trim calculation
00561         factoryTrim[4] =  (-25.0f*131.0f)*(pow( 1.046f , (selfTest[4] - 1.0f) ));             // FT[Yg] factory trim calculation
00562         factoryTrim[5] =  ( 25.0f*131.0f)*(pow( 1.046f , (selfTest[5] - 1.0f) ));             // FT[Zg] factory trim calculation
00563 
00564 //  Output self-test results and factory trim calculation if desired
00565 //  Serial.println(selfTest[0]); Serial.println(selfTest[1]); Serial.println(selfTest[2]);
00566 //  Serial.println(selfTest[3]); Serial.println(selfTest[4]); Serial.println(selfTest[5]);
00567 //  Serial.println(factoryTrim[0]); Serial.println(factoryTrim[1]); Serial.println(factoryTrim[2]);
00568 //  Serial.println(factoryTrim[3]); Serial.println(factoryTrim[4]); Serial.println(factoryTrim[5]);
00569 
00570 // Report results as a ratio of (STR - FT)/FT; the change from Factory Trim of the Self-Test Response
00571 // To get to percent, must multiply by 100 and subtract result from 100
00572         for (int i = 0; i < 6; i++) {
00573             destination[i] = 100.0f + 100.0f*(selfTest[i] - factoryTrim[i])/factoryTrim[i]; // Report percent differences
00574         }
00575 
00576     }
00577 
00578 
00579 // Implementation of Sebastian Madgwick's "...efficient orientation filter for... inertial/magnetic sensor arrays"
00580 // (see http://www.x-io.co.uk/category/open-source/ for examples and more details)
00581 // which fuses acceleration and rotation rate to produce a quaternion-based estimate of relative
00582 // device orientation -- which can be converted to yaw, pitch, and roll. Useful for stabilizing quadcopters, etc.
00583 // The performance of the orientation filter is at least as good as conventional Kalman-based filtering algorithms
00584 // but is much less computationally intensive---it can be performed on a 3.3 V Pro Mini operating at 8 MHz!
00585     void MadgwickQuaternionUpdate(float ax, float ay, float az, float gx, float gy, float gz) {
00586         float q1 = q[0], q2 = q[1], q3 = q[2], q4 = q[3];         // short name local variable for readability
00587         float norm;                                               // vector norm
00588         float f1, f2, f3;                                         // objective funcyion elements
00589         float J_11or24, J_12or23, J_13or22, J_14or21, J_32, J_33; // objective function Jacobian elements
00590         float qDot1, qDot2, qDot3, qDot4;
00591         float hatDot1, hatDot2, hatDot3, hatDot4;
00592         float gerrx, gerry, gerrz, gbiasx, gbiasy, gbiasz;  // gyro bias error
00593 
00594         // Auxiliary variables to avoid repeated arithmetic
00595         float _halfq1 = 0.5f * q1;
00596         float _halfq2 = 0.5f * q2;
00597         float _halfq3 = 0.5f * q3;
00598         float _halfq4 = 0.5f * q4;
00599         float _2q1 = 2.0f * q1;
00600         float _2q2 = 2.0f * q2;
00601         float _2q3 = 2.0f * q3;
00602         float _2q4 = 2.0f * q4;
00603 //            float _2q1q3 = 2.0f * q1 * q3;
00604 //            float _2q3q4 = 2.0f * q3 * q4;
00605 
00606         // Normalise accelerometer measurement
00607         norm = sqrt(ax * ax + ay * ay + az * az);
00608         if (norm == 0.0f) return; // handle NaN
00609         norm = 1.0f/norm;
00610         ax *= norm;
00611         ay *= norm;
00612         az *= norm;
00613 
00614         // Compute the objective function and Jacobian
00615         f1 = _2q2 * q4 - _2q1 * q3 - ax;
00616         f2 = _2q1 * q2 + _2q3 * q4 - ay;
00617         f3 = 1.0f - _2q2 * q2 - _2q3 * q3 - az;
00618         J_11or24 = _2q3;
00619         J_12or23 = _2q4;
00620         J_13or22 = _2q1;
00621         J_14or21 = _2q2;
00622         J_32 = 2.0f * J_14or21;
00623         J_33 = 2.0f * J_11or24;
00624 
00625         // Compute the gradient (matrix multiplication)
00626         hatDot1 = J_14or21 * f2 - J_11or24 * f1;
00627         hatDot2 = J_12or23 * f1 + J_13or22 * f2 - J_32 * f3;
00628         hatDot3 = J_12or23 * f2 - J_33 *f3 - J_13or22 * f1;
00629         hatDot4 = J_14or21 * f1 + J_11or24 * f2;
00630 
00631         // Normalize the gradient
00632         norm = sqrt(hatDot1 * hatDot1 + hatDot2 * hatDot2 + hatDot3 * hatDot3 + hatDot4 * hatDot4);
00633         hatDot1 /= norm;
00634         hatDot2 /= norm;
00635         hatDot3 /= norm;
00636         hatDot4 /= norm;
00637 
00638         // Compute estimated gyroscope biases
00639         gerrx = _2q1 * hatDot2 - _2q2 * hatDot1 - _2q3 * hatDot4 + _2q4 * hatDot3;
00640         gerry = _2q1 * hatDot3 + _2q2 * hatDot4 - _2q3 * hatDot1 - _2q4 * hatDot2;
00641         gerrz = _2q1 * hatDot4 - _2q2 * hatDot3 + _2q3 * hatDot2 - _2q4 * hatDot1;
00642 
00643         // Compute and remove gyroscope biases
00644         gbiasx += gerrx * deltat * zeta;
00645         gbiasy += gerry * deltat * zeta;
00646         gbiasz += gerrz * deltat * zeta;
00647 //           gx -= gbiasx;
00648 //           gy -= gbiasy;
00649 //           gz -= gbiasz;
00650 
00651         // Compute the quaternion derivative
00652         qDot1 = -_halfq2 * gx - _halfq3 * gy - _halfq4 * gz;
00653         qDot2 =  _halfq1 * gx + _halfq3 * gz - _halfq4 * gy;
00654         qDot3 =  _halfq1 * gy - _halfq2 * gz + _halfq4 * gx;
00655         qDot4 =  _halfq1 * gz + _halfq2 * gy - _halfq3 * gx;
00656 
00657         // Compute then integrate estimated quaternion derivative
00658         q1 += (qDot1 -(beta * hatDot1)) * deltat;
00659         q2 += (qDot2 -(beta * hatDot2)) * deltat;
00660         q3 += (qDot3 -(beta * hatDot3)) * deltat;
00661         q4 += (qDot4 -(beta * hatDot4)) * deltat;
00662 
00663         // Normalize the quaternion
00664         norm = sqrt(q1 * q1 + q2 * q2 + q3 * q3 + q4 * q4);    // normalise quaternion
00665         norm = 1.0f/norm;
00666         q[0] = q1 * norm;
00667         q[1] = q2 * norm;
00668         q[2] = q3 * norm;
00669         q[3] = q4 * norm;
00670 
00671     }
00672 
00673 
00674 };
00675 #endif