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kriswiner / MPU9250

Arduino sketches for MPU9250 9DoF with AHRS sensor fusion
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MPU-9250 and SPI code #28

Open bennyber01 opened 8 years ago

bennyber01 commented 8 years ago

/* MPU9250 Basic Example Code by: Kris Winer date: April 1, 2014 license: Beerware - Use this code however you'd like. If you find it useful you can buy me a beer some time.

Demonstrate basic MPU-9250 functionality including parameterizing the register addresses, initializing the sensor, getting properly scaled accelerometer, gyroscope, and magnetometer data out. Added display functions to allow display to on breadboard monitor. Addition of 9 DoF sensor fusion using open source Madgwick and Mahony filter algorithms. Sketch runs on Arduino.

Hardware setup: MPU9250 Breakout --------- Arduino VCC ---------------------- 5V SCLK --------------------- 13 SDI ----------------------- 11 SDO ----------------------- 12 NSC ----------------------- 10 GND ---------------------- GND

Note: The MPU9250 and SPI */

include

define NCS_PIN 10

define MOSI_PIN 11

define MISO_PIN 12

define SCK_PIN 13

const int NCS = NCS_PIN;

uint8_t SPI_read_register( uint8_t reg ) { digitalWrite( NCS, LOW); SPI.transfer( reg | 0x80 ); // reg | 0x80 to denote read uint8_t read_value = SPI.transfer( 0x00 ); // write 8-bits zero digitalWrite( NCS, HIGH); return read_value; }

/****/

void SPI_write_register( uint8_t reg, uint8_t value ) { digitalWrite( NCS, LOW); SPI.transfer( reg ); SPI.transfer( value ); digitalWrite( NCS, HIGH); }

// See also MPU-9250 Register Map and Descriptions, Revision 4.0, RM-MPU-9250A-00, Rev. 1.4, 9/9/2013 for registers not listed in // above document; the MPU9250 and MPU9150 are virtually identical but the latter has a different register map // //Magnetometer Registers

define AK8963_ADDRESS 0x0C

define WHO_AM_I_AK8963 0x00 // should return 0x48

define INFO 0x01

define AK8963_ST1 0x02 // data ready status bit 0

define AK8963_XOUT_L 0x03 // data

define AK8963_XOUT_H 0x04

define AK8963_YOUT_L 0x05

define AK8963_YOUT_H 0x06

define AK8963_ZOUT_L 0x07

define AK8963_ZOUT_H 0x08

define AK8963_ST2 0x09 // Data overflow bit 3 and data read error status bit 2

define AK8963_CNTL 0x0A // Power down (0000), single-measurement (0001), self-test (1000) and Fuse ROM (1111) modes on bits 3:0

define AK8963_ASTC 0x0C // Self test control

define AK8963_I2CDIS 0x0F // I2C disable

define AK8963_ASAX 0x10 // Fuse ROM x-axis sensitivity adjustment value

define AK8963_ASAY 0x11 // Fuse ROM y-axis sensitivity adjustment value

define AK8963_ASAZ 0x12 // Fuse ROM z-axis sensitivity adjustment value

define SELF_TEST_X_GYRO 0x00

define SELF_TEST_Y_GYRO 0x01

define SELF_TEST_Z_GYRO 0x02

/*#define X_FINE_GAIN 0x03 // [7:0] fine gain

define Y_FINE_GAIN 0x04

define Z_FINE_GAIN 0x05

define XA_OFFSET_H 0x06 // User-defined trim values for accelerometer

define XA_OFFSET_L_TC 0x07

define YA_OFFSET_H 0x08

define YA_OFFSET_L_TC 0x09

define ZA_OFFSET_H 0x0A

define ZA_OFFSET_L_TC 0x0B */

define SELF_TEST_X_ACCEL 0x0D

define SELF_TEST_Y_ACCEL 0x0E

define SELF_TEST_Z_ACCEL 0x0F

define SELF_TEST_A 0x10

define XG_OFFSET_H 0x13 // User-defined trim values for gyroscope

define XG_OFFSET_L 0x14

define YG_OFFSET_H 0x15

define YG_OFFSET_L 0x16

define ZG_OFFSET_H 0x17

define ZG_OFFSET_L 0x18

define SMPLRT_DIV 0x19

define CONFIG 0x1A

define GYRO_CONFIG 0x1B

define ACCEL_CONFIG 0x1C

define ACCEL_CONFIG2 0x1D

define LP_ACCEL_ODR 0x1E

define WOM_THR 0x1F

define MOT_DUR 0x20 // Duration counter threshold for motion interrupt generation, 1 kHz rate, LSB = 1 ms

define ZMOT_THR 0x21 // Zero-motion detection threshold bits [7:0]

define ZRMOT_DUR 0x22 // Duration counter threshold for zero motion interrupt generation, 16 Hz rate, LSB = 64 ms

define FIFO_EN 0x23

define I2C_MST_CTRL 0x24

define I2C_SLV0_ADDR 0x25

define I2C_SLV0_REG 0x26

define I2C_SLV0_CTRL 0x27

define I2C_SLV1_ADDR 0x28

define I2C_SLV1_REG 0x29

define I2C_SLV1_CTRL 0x2A

define I2C_SLV2_ADDR 0x2B

define I2C_SLV2_REG 0x2C

define I2C_SLV2_CTRL 0x2D

define I2C_SLV3_ADDR 0x2E

define I2C_SLV3_REG 0x2F

define I2C_SLV3_CTRL 0x30

define I2C_SLV4_ADDR 0x31

define I2C_SLV4_REG 0x32

define I2C_SLV4_DO 0x33

define I2C_SLV4_CTRL 0x34

define I2C_SLV4_DI 0x35

define I2C_MST_STATUS 0x36

define INT_PIN_CFG 0x37

define INT_ENABLE 0x38

define DMP_INT_STATUS 0x39 // Check DMP interrupt

define INT_STATUS 0x3A

define ACCEL_XOUT_H 0x3B

define ACCEL_XOUT_L 0x3C

define ACCEL_YOUT_H 0x3D

define ACCEL_YOUT_L 0x3E

define ACCEL_ZOUT_H 0x3F

define ACCEL_ZOUT_L 0x40

define TEMP_OUT_H 0x41

define TEMP_OUT_L 0x42

define GYRO_XOUT_H 0x43

define GYRO_XOUT_L 0x44

define GYRO_YOUT_H 0x45

define GYRO_YOUT_L 0x46

define GYRO_ZOUT_H 0x47

define GYRO_ZOUT_L 0x48

define EXT_SENS_DATA_00 0x49

define EXT_SENS_DATA_01 0x4A

define EXT_SENS_DATA_02 0x4B

define EXT_SENS_DATA_03 0x4C

define EXT_SENS_DATA_04 0x4D

define EXT_SENS_DATA_05 0x4E

define EXT_SENS_DATA_06 0x4F

define EXT_SENS_DATA_07 0x50

define EXT_SENS_DATA_08 0x51

define EXT_SENS_DATA_09 0x52

define EXT_SENS_DATA_10 0x53

define EXT_SENS_DATA_11 0x54

define EXT_SENS_DATA_12 0x55

define EXT_SENS_DATA_13 0x56

define EXT_SENS_DATA_14 0x57

define EXT_SENS_DATA_15 0x58

define EXT_SENS_DATA_16 0x59

define EXT_SENS_DATA_17 0x5A

define EXT_SENS_DATA_18 0x5B

define EXT_SENS_DATA_19 0x5C

define EXT_SENS_DATA_20 0x5D

define EXT_SENS_DATA_21 0x5E

define EXT_SENS_DATA_22 0x5F

define EXT_SENS_DATA_23 0x60

define MOT_DETECT_STATUS 0x61

define I2C_SLV0_DO 0x63

define I2C_SLV1_DO 0x64

define I2C_SLV2_DO 0x65

define I2C_SLV3_DO 0x66

define I2C_MST_DELAY_CTRL 0x67

define SIGNAL_PATH_RESET 0x68

define MOT_DETECT_CTRL 0x69

define USER_CTRL 0x6A // Bit 7 enable DMP, bit 3 reset DMP

define PWR_MGMT_1 0x6B // Device defaults to the SLEEP mode

define PWR_MGMT_2 0x6C

define DMP_BANK 0x6D // Activates a specific bank in the DMP

define DMP_RW_PNT 0x6E // Set read/write pointer to a specific start address in specified DMP bank

define DMP_REG 0x6F // Register in DMP from which to read or to which to write

define DMP_REG_1 0x70

define DMP_REG_2 0x71

define FIFO_COUNTH 0x72

define FIFO_COUNTL 0x73

define FIFO_R_W 0x74

define WHO_AM_I_MPU9250 0x75 // Should return 0x71

define XA_OFFSET_H 0x77

define XA_OFFSET_L 0x78

define YA_OFFSET_H 0x7A

define YA_OFFSET_L 0x7B

define ZA_OFFSET_H 0x7D

define ZA_OFFSET_L 0x7E

// Using the MSENSR-9250 breakout board, ADO is set to 0 // Seven-bit device address is 110100 for ADO = 0 and 110101 for ADO = 1

define ADO 1

if ADO

define MPU9250_ADDRESS 0x69 // Device address when ADO = 1

else

define MPU9250_ADDRESS 0x68 // Device address when ADO = 0

define AK8963_ADDRESS 0x0C // Address of magnetometer

endif

define AHRS true // set to false for basic data read

define SerialDebug true // set to true to get Serial output for debugging

// Set initial input parameters enum Ascale { AFS_2G = 0, AFS_4G, AFS_8G, AFS_16G };

enum Gscale { GFS_250DPS = 0, GFS_500DPS, GFS_1000DPS, GFS_2000DPS };

enum Mscale { MFS_14BITS = 0, // 0.6 mG per LSB MFS_16BITS // 0.15 mG per LSB };

// Specify sensor full scale uint8_t Gscale = GFS_250DPS; uint8_t Ascale = AFS_2G; uint8_t Mscale = MFS_16BITS; // Choose either 14-bit or 16-bit magnetometer resolution uint8_t Mmode = 0x02; // 2 for 8 Hz, 6 for 100 Hz continuous magnetometer data read float aRes, gRes, mRes; // scale resolutions per LSB for the sensors

// Pin definitions int intPin = 12; // These can be changed, 2 and 3 are the Arduinos ext int pins int myLed = 13; // Set up pin 13 led for toggling

int16_t accelCount[3]; // Stores the 16-bit signed accelerometer sensor output int16_t gyroCount[3]; // Stores the 16-bit signed gyro sensor output int16_t magCount[3]; // Stores the 16-bit signed magnetometer sensor output float magCalibration[3] = {0, 0, 0}, magbias[3] = {0, 0, 0}; // Factory mag calibration and mag bias float gyroBias[3] = {0, 0, 0}, accelBias[3] = {0, 0, 0}; // Bias corrections for gyro and accelerometer int16_t tempCount; // temperature raw count output float temperature; // Stores the real internal chip temperature in degrees Celsius float SelfTest[6]; // holds results of gyro and accelerometer self test

// global constants for 9 DoF fusion and AHRS (Attitude and Heading Reference System) float GyroMeasError = PI * (40.0f / 180.0f); // gyroscope measurement error in rads/s (start at 40 deg/s) float GyroMeasDrift = PI * (0.0f / 180.0f); // gyroscope measurement drift in rad/s/s (start at 0.0 deg/s/s) // There is a tradeoff in the beta parameter between accuracy and response speed. // In the original Madgwick study, beta of 0.041 (corresponding to GyroMeasError of 2.7 degrees/s) was found to give optimal accuracy. // However, with this value, the LSM9SD0 response time is about 10 seconds to a stable initial quaternion. // Subsequent changes also require a longish lag time to a stable output, not fast enough for a quadcopter or robot car! // By increasing beta (GyroMeasError) by about a factor of fifteen, the response time constant is reduced to ~2 sec // I haven't noticed any reduction in solution accuracy. This is essentially the I coefficient in a PID control sense; // the bigger the feedback coefficient, the faster the solution converges, usually at the expense of accuracy. // In any case, this is the free parameter in the Madgwick filtering and fusion scheme. float beta = sqrt(3.0f / 4.0f) * GyroMeasError; // compute beta 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

define Kp 2.0f * 5.0f // these are the free parameters in the Mahony filter and fusion scheme, Kp for proportional feedback, Ki for integral

define Ki 0.0f

uint32_t delt_t = 0; // used to control display output rate uint32_t count = 0, sumCount = 0; // used to control display output rate float pitch, yaw, roll; float deltat = 0.0f, sum = 0.0f; // integration interval for both filter schemes uint32_t lastUpdate = 0, firstUpdate = 0; // used to calculate integration interval uint32_t Now = 0; // used to calculate integration interval

float ax, ay, az, gx, gy, gz, mx, my, mz; // variables to hold latest sensor data values float q[4] = {1.0f, 0.0f, 0.0f, 0.0f}; // vector to hold quaternion float eInt[3] = {0.0f, 0.0f, 0.0f}; // vector to hold integral error for Mahony method

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

// Implementation of Sebastian Madgwick's "...efficient orientation filter for... inertial/magnetic sensor arrays" // (see http://www.x-io.co.uk/category/open-source/ for examples and more details) // which fuses acceleration, rotation rate, and magnetic moments to produce a quaternion-based estimate of absolute // device orientation -- which can be converted to yaw, pitch, and roll. Useful for stabilizing quadcopters, etc. // The performance of the orientation filter is at least as good as conventional Kalman-based filtering algorithms // but is much less computationally intensive---it can be performed on a 3.3 V Pro Mini operating at 8 MHz! void MadgwickQuaternionUpdate(float ax, float ay, float az, float gx, float gy, float gz, float mx, float my, float mz) { float q1 = q[0], q2 = q[1], q3 = q[2], q4 = q[3]; // short name local variable for readability float norm; float hx, hy, _2bx, _2bz; float s1, s2, s3, s4; float qDot1, qDot2, qDot3, qDot4;

        // Auxiliary variables to avoid repeated arithmetic
        float _2q1mx;
        float _2q1my;
        float _2q1mz;
        float _2q2mx;
        float _4bx;
        float _4bz;
        float _2q1 = 2.0f * q1;
        float _2q2 = 2.0f * q2;
        float _2q3 = 2.0f * q3;
        float _2q4 = 2.0f * q4;
        float _2q1q3 = 2.0f * q1 * q3;
        float _2q3q4 = 2.0f * q3 * q4;
        float q1q1 = q1 * q1;
        float q1q2 = q1 * q2;
        float q1q3 = q1 * q3;
        float q1q4 = q1 * q4;
        float q2q2 = q2 * q2;
        float q2q3 = q2 * q3;
        float q2q4 = q2 * q4;
        float q3q3 = q3 * q3;
        float q3q4 = q3 * q4;
        float q4q4 = q4 * q4;

        // Normalise accelerometer measurement
        norm = sqrt(ax * ax + ay * ay + az * az);
        if (norm == 0.0f) return; // handle NaN
        norm = 1.0f/norm;
        ax *= norm;
        ay *= norm;
        az *= norm;

        // Normalise magnetometer measurement
        norm = sqrt(mx * mx + my * my + mz * mz);
        if (norm == 0.0f) return; // handle NaN
        norm = 1.0f/norm;
        mx *= norm;
        my *= norm;
        mz *= norm;

        // Reference direction of Earth's magnetic field
        _2q1mx = 2.0f * q1 * mx;
        _2q1my = 2.0f * q1 * my;
        _2q1mz = 2.0f * q1 * mz;
        _2q2mx = 2.0f * q2 * mx;
        hx = mx * q1q1 - _2q1my * q4 + _2q1mz * q3 + mx * q2q2 + _2q2 * my * q3 + _2q2 * mz * q4 - mx * q3q3 - mx * q4q4;
        hy = _2q1mx * q4 + my * q1q1 - _2q1mz * q2 + _2q2mx * q3 - my * q2q2 + my * q3q3 + _2q3 * mz * q4 - my * q4q4;
        _2bx = sqrt(hx * hx + hy * hy);
        _2bz = -_2q1mx * q3 + _2q1my * q2 + mz * q1q1 + _2q2mx * q4 - mz * q2q2 + _2q3 * my * q4 - mz * q3q3 + mz * q4q4;
        _4bx = 2.0f * _2bx;
        _4bz = 2.0f * _2bz;

        // Gradient decent algorithm corrective step
        s1 = -_2q3 * (2.0f * q2q4 - _2q1q3 - ax) + _2q2 * (2.0f * q1q2 + _2q3q4 - ay) - _2bz * q3 * (_2bx * (0.5f - q3q3 - q4q4) + _2bz * (q2q4 - q1q3) - mx) + (-_2bx * q4 + _2bz * q2) * (_2bx * (q2q3 - q1q4) + _2bz * (q1q2 + q3q4) - my) + _2bx * q3 * (_2bx * (q1q3 + q2q4) + _2bz * (0.5f - q2q2 - q3q3) - mz);
        s2 = _2q4 * (2.0f * q2q4 - _2q1q3 - ax) + _2q1 * (2.0f * q1q2 + _2q3q4 - ay) - 4.0f * q2 * (1.0f - 2.0f * q2q2 - 2.0f * q3q3 - az) + _2bz * q4 * (_2bx * (0.5f - q3q3 - q4q4) + _2bz * (q2q4 - q1q3) - mx) + (_2bx * q3 + _2bz * q1) * (_2bx * (q2q3 - q1q4) + _2bz * (q1q2 + q3q4) - my) + (_2bx * q4 - _4bz * q2) * (_2bx * (q1q3 + q2q4) + _2bz * (0.5f - q2q2 - q3q3) - mz);
        s3 = -_2q1 * (2.0f * q2q4 - _2q1q3 - ax) + _2q4 * (2.0f * q1q2 + _2q3q4 - ay) - 4.0f * q3 * (1.0f - 2.0f * q2q2 - 2.0f * q3q3 - az) + (-_4bx * q3 - _2bz * q1) * (_2bx * (0.5f - q3q3 - q4q4) + _2bz * (q2q4 - q1q3) - mx) + (_2bx * q2 + _2bz * q4) * (_2bx * (q2q3 - q1q4) + _2bz * (q1q2 + q3q4) - my) + (_2bx * q1 - _4bz * q3) * (_2bx * (q1q3 + q2q4) + _2bz * (0.5f - q2q2 - q3q3) - mz);
        s4 = _2q2 * (2.0f * q2q4 - _2q1q3 - ax) + _2q3 * (2.0f * q1q2 + _2q3q4 - ay) + (-_4bx * q4 + _2bz * q2) * (_2bx * (0.5f - q3q3 - q4q4) + _2bz * (q2q4 - q1q3) - mx) + (-_2bx * q1 + _2bz * q3) * (_2bx * (q2q3 - q1q4) + _2bz * (q1q2 + q3q4) - my) + _2bx * q2 * (_2bx * (q1q3 + q2q4) + _2bz * (0.5f - q2q2 - q3q3) - mz);
        norm = sqrt(s1 * s1 + s2 * s2 + s3 * s3 + s4 * s4);    // normalise step magnitude
        norm = 1.0f/norm;
        s1 *= norm;
        s2 *= norm;
        s3 *= norm;
        s4 *= norm;

        // Compute rate of change of quaternion
        qDot1 = 0.5f * (-q2 * gx - q3 * gy - q4 * gz) - beta * s1;
        qDot2 = 0.5f * (q1 * gx + q3 * gz - q4 * gy) - beta * s2;
        qDot3 = 0.5f * (q1 * gy - q2 * gz + q4 * gx) - beta * s3;
        qDot4 = 0.5f * (q1 * gz + q2 * gy - q3 * gx) - beta * s4;

        // Integrate to yield quaternion
        q1 += qDot1 * deltat;
        q2 += qDot2 * deltat;
        q3 += qDot3 * deltat;
        q4 += qDot4 * deltat;
        norm = sqrt(q1 * q1 + q2 * q2 + q3 * q3 + q4 * q4);    // normalise quaternion
        norm = 1.0f/norm;
        q[0] = q1 * norm;
        q[1] = q2 * norm;
        q[2] = q3 * norm;
        q[3] = q4 * norm;

    }

// Similar to Madgwick scheme but uses proportional and integral filtering on the error between estimated reference vectors and // measured ones. void MahonyQuaternionUpdate(float ax, float ay, float az, float gx, float gy, float gz, float mx, float my, float mz) { float q1 = q[0], q2 = q[1], q3 = q[2], q4 = q[3]; // short name local variable for readability float norm; float hx, hy, bx, bz; float vx, vy, vz, wx, wy, wz; float ex, ey, ez; float pa, pb, pc;

        // Auxiliary variables to avoid repeated arithmetic
        float q1q1 = q1 * q1;
        float q1q2 = q1 * q2;
        float q1q3 = q1 * q3;
        float q1q4 = q1 * q4;
        float q2q2 = q2 * q2;
        float q2q3 = q2 * q3;
        float q2q4 = q2 * q4;
        float q3q3 = q3 * q3;
        float q3q4 = q3 * q4;
        float q4q4 = q4 * q4;   

        // Normalise accelerometer measurement
        norm = sqrt(ax * ax + ay * ay + az * az);
        if (norm == 0.0f) return; // handle NaN
        norm = 1.0f / norm;        // use reciprocal for division
        ax *= norm;
        ay *= norm;
        az *= norm;

        // Normalise magnetometer measurement
        norm = sqrt(mx * mx + my * my + mz * mz);
        if (norm == 0.0f) return; // handle NaN
        norm = 1.0f / norm;        // use reciprocal for division
        mx *= norm;
        my *= norm;
        mz *= norm;

        // Reference direction of Earth's magnetic field
        hx = 2.0f * mx * (0.5f - q3q3 - q4q4) + 2.0f * my * (q2q3 - q1q4) + 2.0f * mz * (q2q4 + q1q3);
        hy = 2.0f * mx * (q2q3 + q1q4) + 2.0f * my * (0.5f - q2q2 - q4q4) + 2.0f * mz * (q3q4 - q1q2);
        bx = sqrt((hx * hx) + (hy * hy));
        bz = 2.0f * mx * (q2q4 - q1q3) + 2.0f * my * (q3q4 + q1q2) + 2.0f * mz * (0.5f - q2q2 - q3q3);

        // Estimated direction of gravity and magnetic field
        vx = 2.0f * (q2q4 - q1q3);
        vy = 2.0f * (q1q2 + q3q4);
        vz = q1q1 - q2q2 - q3q3 + q4q4;
        wx = 2.0f * bx * (0.5f - q3q3 - q4q4) + 2.0f * bz * (q2q4 - q1q3);
        wy = 2.0f * bx * (q2q3 - q1q4) + 2.0f * bz * (q1q2 + q3q4);
        wz = 2.0f * bx * (q1q3 + q2q4) + 2.0f * bz * (0.5f - q2q2 - q3q3);  

        // Error is cross product between estimated direction and measured direction of gravity
        ex = (ay * vz - az * vy) + (my * wz - mz * wy);
        ey = (az * vx - ax * vz) + (mz * wx - mx * wz);
        ez = (ax * vy - ay * vx) + (mx * wy - my * wx);
        if (Ki > 0.0f)
        {
            eInt[0] += ex;      // accumulate integral error
            eInt[1] += ey;
            eInt[2] += ez;
        }
        else
        {
            eInt[0] = 0.0f;     // prevent integral wind up
            eInt[1] = 0.0f;
            eInt[2] = 0.0f;
        }

        // Apply feedback terms
        gx = gx + Kp * ex + Ki * eInt[0];
        gy = gy + Kp * ey + Ki * eInt[1];
        gz = gz + Kp * ez + Ki * eInt[2];

        // Integrate rate of change of quaternion
        pa = q2;
        pb = q3;
        pc = q4;
        q1 = q1 + (-q2 * gx - q3 * gy - q4 * gz) * (0.5f * deltat);
        q2 = pa + (q1 * gx + pb * gz - pc * gy) * (0.5f * deltat);
        q3 = pb + (q1 * gy - pa * gz + pc * gx) * (0.5f * deltat);
        q4 = pc + (q1 * gz + pa * gy - pb * gx) * (0.5f * deltat);

        // Normalise quaternion
        norm = sqrt(q1 * q1 + q2 * q2 + q3 * q3 + q4 * q4);
        norm = 1.0f / norm;
        q[0] = q1 * norm;
        q[1] = q2 * norm;
        q[2] = q3 * norm;
        q[3] = q4 * norm;

    }

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

void setup() { //Wire.begin(); // TWBR = 12; // 400 kbit/sec I2C speed Serial.begin(38400);

// Set up the interrupt pin, its set as active high, push-pull pinMode(intPin, INPUT); digitalWrite(intPin, LOW); pinMode(myLed, OUTPUT); digitalWrite(myLed, HIGH);

delay(1000);

// Read the WHO_AM_I register, this is a good test of communication //byte c = readByte(MPU9250_ADDRESS, WHO_AM_I_MPU9250); // Read WHO_AM_I register for MPU-9250 //Serial.print("MPU9250 "); Serial.print("I AM "); Serial.print(c, HEX); Serial.print(" I should be "); Serial.println(0x71, HEX);

byte id;

Serial.begin( 115200 );

pinMode( NCS_PIN, OUTPUT ); pinMode( MOSI_PIN, OUTPUT ); pinMode( MISO_PIN, INPUT ); pinMode( SCK_PIN, OUTPUT );

SPI.begin( ); SPI.setDataMode( SPI_MODE3 ); SPI.setBitOrder( MSBFIRST ); SPI.setClockDivider( 16 ); // 1MHz digitalWrite(NCS, HIGH); delay( 1000 );

Serial.println( "MPU9250 SPI" );

// reset the device SPI_write_register( 0x6B, 0x80 ); delay( 100 );

// disable I2C protocol SPI_write_register( 0x6A, 0x10 ); delay( 100 );

// reset acc, gyro and temp SPI_write_register( 0x68, 0x07 ); delay( 100 );

if(SPI_read_register(0x75) == 0x71) {
Serial.println("MPU9250 is online...");

MPU9250SelfTest(SelfTest); // Start by performing self test and reporting values
Serial.print("x-axis self test: acceleration trim within : "); Serial.print(SelfTest[0],1); Serial.println("% of factory value");
Serial.print("y-axis self test: acceleration trim within : "); Serial.print(SelfTest[1],1); Serial.println("% of factory value");
Serial.print("z-axis self test: acceleration trim within : "); Serial.print(SelfTest[2],1); Serial.println("% of factory value");
Serial.print("x-axis self test: gyration trim within : "); Serial.print(SelfTest[3],1); Serial.println("% of factory value");
Serial.print("y-axis self test: gyration trim within : "); Serial.print(SelfTest[4],1); Serial.println("% of factory value");
Serial.print("z-axis self test: gyration trim within : "); Serial.print(SelfTest[5],1); Serial.println("% of factory value");

calibrateMPU9250(gyroBias, accelBias); // Calibrate gyro and accelerometers, load biases in bias registers

delay(1000); 

initMPU9250(); 
Serial.println("MPU9250 initialized for active data mode...."); // Initialize device for active mode read of acclerometer, gyroscope, and temperature

// Read the WHO_AM_I register of the magnetometer, this is a good test of communication
byte d = readByte(AK8963_ADDRESS, WHO_AM_I_AK8963);  // Read WHO_AM_I register for AK8963
Serial.print("AK8963 "); Serial.print("I AM "); Serial.print(d, HEX); Serial.print(" I should be "); Serial.println(0x48, HEX);

delay(1000); 

// Get magnetometer calibration from AK8963 ROM
initAK8963(magCalibration); Serial.println("AK8963 initialized for active data mode...."); // Initialize device for active mode read of magnetometer

if(SerialDebug) { // Serial.println("Calibration values: "); Serial.print("X-Axis sensitivity adjustment value "); Serial.println(magCalibration[0], 2); Serial.print("Y-Axis sensitivity adjustment value "); Serial.println(magCalibration[1], 2); Serial.print("Z-Axis sensitivity adjustment value "); Serial.println(magCalibration[2], 2); }

delay(1000);

} else { Serial.print("Could not connect to MPU9250"); while(1) ; // Loop forever if communication doesn't happen } }

void loop() {
// If intPin goes high, all data registers have new data if (readByte(MPU9250_ADDRESS, INT_STATUS) & 0x01) { // On interrupt, check if data ready interrupt readAccelData(accelCount); // Read the x/y/z adc values getAres();

// Now we'll calculate the accleration value into actual g's
ax = (float)accelCount[0]*aRes; // - accelBias[0];  // get actual g value, this depends on scale being set
ay = (float)accelCount[1]*aRes; // - accelBias[1];   
az = (float)accelCount[2]*aRes; // - accelBias[2];  

readGyroData(gyroCount);  // Read the x/y/z adc values
getGres();

// Calculate the gyro value into actual degrees per second
gx = (float)gyroCount[0]*gRes;  // get actual gyro value, this depends on scale being set
gy = (float)gyroCount[1]*gRes;  
gz = (float)gyroCount[2]*gRes;   

readMagData(magCount);  // Read the x/y/z adc values
getMres();
magbias[0] = +470.;  // User environmental x-axis correction in milliGauss, should be automatically calculated
magbias[1] = +120.;  // User environmental x-axis correction in milliGauss
magbias[2] = +125.;  // User environmental x-axis correction in milliGauss

// Calculate the magnetometer values in milliGauss
// Include factory calibration per data sheet and user environmental corrections
mx = (float)magCount[0]*mRes*magCalibration[0] - magbias[0];  // get actual magnetometer value, this depends on scale being set
my = (float)magCount[1]*mRes*magCalibration[1] - magbias[1];  
mz = (float)magCount[2]*mRes*magCalibration[2] - magbias[2];

}

Now = micros(); deltat = ((Now - lastUpdate)/1000000.0f); // set integration time by time elapsed since last filter update lastUpdate = Now;

sum += deltat; // sum for averaging filter update rate sumCount++;

// Sensors x (y)-axis of the accelerometer is aligned with the y (x)-axis of the magnetometer; // the magnetometer z-axis (+ down) is opposite to z-axis (+ up) of accelerometer and gyro! // We have to make some allowance for this orientationmismatch in feeding the output to the quaternion filter. // For the MPU-9250, we have chosen a magnetic rotation that keeps the sensor forward along the x-axis just like // in the LSM9DS0 sensor. This rotation can be modified to allow any convenient orientation convention. // This is ok by aircraft orientation standards!
// Pass gyro rate as rad/s // MadgwickQuaternionUpdate(ax, ay, az, gx_PI/180.0f, gy_PI/180.0f, gz_PI/180.0f, my, mx, mz); MahonyQuaternionUpdate(ax, ay, az, gx_PI/180.0f, gy_PI/180.0f, gz_PI/180.0f, my, mx, mz);

if (!AHRS) {
delt_t = millis() - count;
if(delt_t > 500) {

if(SerialDebug) {
// Print acceleration values in milligs!
Serial.print("X-acceleration: "); Serial.print(1000*ax); Serial.print(" mg ");
Serial.print("Y-acceleration: "); Serial.print(1000*ay); Serial.print(" mg ");
Serial.print("Z-acceleration: "); Serial.print(1000*az); Serial.println(" mg ");

// Print gyro values in degree/sec
Serial.print("X-gyro rate: "); Serial.print(gx, 3); Serial.print(" degrees/sec "); 
Serial.print("Y-gyro rate: "); Serial.print(gy, 3); Serial.print(" degrees/sec "); 
Serial.print("Z-gyro rate: "); Serial.print(gz, 3); Serial.println(" degrees/sec"); 

// Print mag values in degree/sec
Serial.print("X-mag field: "); Serial.print(mx); Serial.print(" mG "); 
Serial.print("Y-mag field: "); Serial.print(my); Serial.print(" mG "); 
Serial.print("Z-mag field: "); Serial.print(mz); Serial.println(" mG"); 

tempCount = readTempData();  // Read the adc values
temperature = ((float) tempCount) / 333.87 + 21.0; // Temperature in degrees Centigrade

// Print temperature in degrees Centigrade
Serial.print("Temperature is "); Serial.print(temperature, 1); Serial.println(" degrees C"); // Print T values to tenths of s degree C }

count = millis();
digitalWrite(myLed, !digitalRead(myLed));  // toggle led
}
}
else {

// Serial print and/or display at 0.5 s rate independent of data rates
delt_t = millis() - count;
if (delt_t > 500) { // update LCD once per half-second independent of read rate

if(SerialDebug) {
Serial.print("ax = "); Serial.print((int)1000*ax);  
Serial.print(" ay = "); Serial.print((int)1000*ay); 
Serial.print(" az = "); Serial.print((int)1000*az); Serial.println(" mg");
Serial.print("gx = "); Serial.print( gx, 2); 
Serial.print(" gy = "); Serial.print( gy, 2); 
Serial.print(" gz = "); Serial.print( gz, 2); Serial.println(" deg/s");
Serial.print("mx = "); Serial.print( (int)mx ); 
Serial.print(" my = "); Serial.print( (int)my ); 
Serial.print(" mz = "); Serial.print( (int)mz ); Serial.println(" mG");

Serial.print("q0 = "); Serial.print(q[0]);
Serial.print(" qx = "); Serial.print(q[1]); 
Serial.print(" qy = "); Serial.print(q[2]); 
Serial.print(" qz = "); Serial.println(q[3]); 
}

// Define output variables from updated quaternion---these are Tait-Bryan angles, commonly used in aircraft orientation. // In this coordinate system, the positive z-axis is down toward Earth. // Yaw is the angle between Sensor x-axis and Earth magnetic North (or true North if corrected for local declination, looking down on the sensor positive yaw is counterclockwise. // Pitch is angle between sensor x-axis and Earth ground plane, toward the Earth is positive, up toward the sky is negative. // Roll is angle between sensor y-axis and Earth ground plane, y-axis up is positive roll. // These arise from the definition of the homogeneous rotation matrix constructed from quaternions. // Tait-Bryan angles as well as Euler angles are non-commutative; that is, the get the correct orientation the rotations must be // applied in the correct order which for this configuration is yaw, pitch, and then roll. // For more see http://en.wikipedia.org/wiki/Conversion_between_quaternions_and_Euler_angles which has additional links. yaw = atan2(2.0f * (q[1] * q[2] + q[0] * q[3]), q[0] * q[0] + q[1] * q[1] - q[2] * q[2] - q[3] * q[3]);
pitch = -asin(2.0f * (q[1] * q[3] - q[0] * q[2])); roll = atan2(2.0f * (q[0] * q[1] + q[2] * q[3]), q[0] * q[0] - q[1] * q[1] - q[2] * q[2] + q[3] * q[3]); pitch = 180.0f / PI; yaw = 180.0f / PI; yaw -= 13.8; // Declination at Danville, California is 13 degrees 48 minutes and 47 seconds on 2014-04-04 roll *= 180.0f / PI;

if(SerialDebug) {
Serial.print("Yaw, Pitch, Roll: ");
Serial.print(yaw, 2);
Serial.print(", ");
Serial.print(pitch, 2);
Serial.print(", ");
Serial.println(roll, 2);

Serial.print("rate = "); Serial.print((float)sumCount/sum, 2); Serial.println(" Hz");
}

// With these settings the filter is updating at a ~145 Hz rate using the Madgwick scheme and 
// >200 Hz using the Mahony scheme even though the display refreshes at only 2 Hz.
// The filter update rate is determined mostly by the mathematical steps in the respective algorithms, 
// the processor speed (8 MHz for the 3.3V Pro Mini), and the magnetometer ODR:
// an ODR of 10 Hz for the magnetometer produce the above rates, maximum magnetometer ODR of 100 Hz produces
// filter update rates of 36 - 145 and ~38 Hz for the Madgwick and Mahony schemes, respectively. 
// This is presumably because the magnetometer read takes longer than the gyro or accelerometer reads.
// This filter update rate should be fast enough to maintain accurate platform orientation for 
// stabilization control of a fast-moving robot or quadcopter. Compare to the update rate of 200 Hz
// produced by the on-board Digital Motion Processor of Invensense's MPU6050 6 DoF and MPU9150 9DoF sensors.
// The 3.3 V 8 MHz Pro Mini is doing pretty well!

count = millis(); 
sumCount = 0;
sum = 0;    
}
}

}

//=================================================================================================================== //====== Set of useful function to access acceleration. gyroscope, magnetometer, and temperature data //===================================================================================================================

void getMres() { switch (Mscale) { // Possible magnetometer scales (and their register bit settings) are: // 14 bit resolution (0) and 16 bit resolution (1) case MFS_14BITS: mRes = 10._4912./8190.; // Proper scale to return milliGauss break; case MFS_16BITS: mRes = 10._4912./32760.0; // Proper scale to return milliGauss break; } }

void getGres() { switch (Gscale) { // Possible gyro scales (and their register bit settings) are: // 250 DPS (00), 500 DPS (01), 1000 DPS (10), and 2000 DPS (11). // Here's a bit of an algorith to calculate DPS/(ADC tick) based on that 2-bit value: case GFS_250DPS: gRes = 250.0/32768.0; break; case GFS_500DPS: gRes = 500.0/32768.0; break; case GFS_1000DPS: gRes = 1000.0/32768.0; break; case GFS_2000DPS: gRes = 2000.0/32768.0; break; } }

void getAres() { switch (Ascale) { // Possible accelerometer scales (and their register bit settings) are: // 2 Gs (00), 4 Gs (01), 8 Gs (10), and 16 Gs (11). // Here's a bit of an algorith to calculate DPS/(ADC tick) based on that 2-bit value: case AFS_2G: aRes = 2.0/32768.0; break; case AFS_4G: aRes = 4.0/32768.0; break; case AFS_8G: aRes = 8.0/32768.0; break; case AFS_16G: aRes = 16.0/32768.0; break; } }

void readAccelData(int16_t * destination) { uint8_t rawData[6]; // x/y/z accel register data stored here readBytes(MPU9250_ADDRESS, ACCEL_XOUT_H, 6, &rawData[0]); // Read the six raw data registers into data array destination[0] = ((int16_t)rawData[0] << 8) | rawData[1] ; // Turn the MSB and LSB into a signed 16-bit value destination[1] = ((int16_t)rawData[2] << 8) | rawData[3] ;
destination[2] = ((int16_t)rawData[4] << 8) | rawData[5] ; }

void readGyroData(int16_t * destination) { uint8_t rawData[6]; // x/y/z gyro register data stored here readBytes(MPU9250_ADDRESS, GYRO_XOUT_H, 6, &rawData[0]); // Read the six raw data registers sequentially into data array destination[0] = ((int16_t)rawData[0] << 8) | rawData[1] ; // Turn the MSB and LSB into a signed 16-bit value destination[1] = ((int16_t)rawData[2] << 8) | rawData[3] ;
destination[2] = ((int16_t)rawData[4] << 8) | rawData[5] ; }

void readMagData(int16_t * destination) { uint8_t rawData[7]; // x/y/z gyro register data, ST2 register stored here, must read ST2 at end of data acquisition if(readByte(AK8963_ADDRESS, AK8963_ST1) & 0x01) { // wait for magnetometer data ready bit to be set readBytes(AK8963_ADDRESS, AK8963_XOUT_L, 7, &rawData[0]); // Read the six raw data and ST2 registers sequentially into data array uint8_t c = rawData[6]; // End data read by reading ST2 register if(!(c & 0x08)) { // Check if magnetic sensor overflow set, if not then report data destination[0] = ((int16_t)rawData[1] << 8) | rawData[0] ; // Turn the MSB and LSB into a signed 16-bit value destination[1] = ((int16_t)rawData[3] << 8) | rawData[2] ; // Data stored as little Endian destination[2] = ((int16_t)rawData[5] << 8) | rawData[4] ; } } }

int16_t readTempData() { uint8_t rawData[2]; // x/y/z gyro register data stored here readBytes(MPU9250_ADDRESS, TEMP_OUT_H, 2, &rawData[0]); // Read the two raw data registers sequentially into data array return ((int16_t)rawData[0] << 8) | rawData[1] ; // Turn the MSB and LSB into a 16-bit value }

void initAK8963(float * destination) { // First extract the factory calibration for each magnetometer axis uint8_t rawData[3]; // x/y/z gyro calibration data stored here writeByte(AK8963_ADDRESS, AK8963_CNTL, 0x00); // Power down magnetometer
delay(10); writeByte(AK8963_ADDRESS, AK8963_CNTL, 0x0F); // Enter Fuse ROM access mode delay(10); readBytes(AK8963_ADDRESS, AK8963_ASAX, 3, &rawData[0]); // Read the x-, y-, and z-axis calibration values destination[0] = (float)(rawData[0] - 128)/256. + 1.; // Return x-axis sensitivity adjustment values, etc. destination[1] = (float)(rawData[1] - 128)/256. + 1.;
destination[2] = (float)(rawData[2] - 128)/256. + 1.; writeByte(AK8963_ADDRESS, AK8963_CNTL, 0x00); // Power down magnetometer
delay(10); // Configure the magnetometer for continuous read and highest resolution // set Mscale bit 4 to 1 (0) to enable 16 (14) bit resolution in CNTL register, // and enable continuous mode data acquisition Mmode (bits [3:0]), 0010 for 8 Hz and 0110 for 100 Hz sample rates writeByte(AK8963_ADDRESS, AK8963_CNTL, Mscale << 4 | Mmode); // Set magnetometer data resolution and sample ODR delay(10); }

void initMPU9250() {
// wake up device writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x00); // Clear sleep mode bit (6), enable all sensors delay(100); // Wait for all registers to reset

// get stable time source writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x01); // Auto select clock source to be PLL gyroscope reference if ready else delay(200);

// Configure Gyro and Thermometer // Disable FSYNC and set thermometer and gyro bandwidth to 41 and 42 Hz, respectively; // minimum delay time for this setting is 5.9 ms, which means sensor fusion update rates cannot // be higher than 1 / 0.0059 = 170 Hz // DLPF_CFG = bits 2:0 = 011; this limits the sample rate to 1000 Hz for both // With the MPU9250, it is possible to get gyro sample rates of 32 kHz (!), 8 kHz, or 1 kHz writeByte(MPU9250_ADDRESS, CONFIG, 0x03);

// Set sample rate = gyroscope output rate/(1 + SMPLRT_DIV) writeByte(MPU9250_ADDRESS, SMPLRT_DIV, 0x04); // Use a 200 Hz rate; a rate consistent with the filter update rate // determined inset in CONFIG above

// Set gyroscope full scale range // Range selects FS_SEL and AFS_SEL are 0 - 3, so 2-bit values are left-shifted into positions 4:3 uint8_t c = readByte(MPU9250_ADDRESS, GYRO_CONFIG); // writeRegister(GYRO_CONFIG, c & ~0xE0); // Clear self-test bits [7:5] writeByte(MPU9250_ADDRESS, GYRO_CONFIG, c & ~0x02); // Clear Fchoice bits [1:0] writeByte(MPU9250_ADDRESS, GYRO_CONFIG, c & ~0x18); // Clear AFS bits [4:3] writeByte(MPU9250_ADDRESS, GYRO_CONFIG, c | Gscale << 3); // Set full scale range for the gyro // writeRegister(GYRO_CONFIG, c | 0x00); // Set Fchoice for the gyro to 11 by writing its inverse to bits 1:0 of GYRO_CONFIG

// Set accelerometer full-scale range configuration c = readByte(MPU9250_ADDRESS, ACCEL_CONFIG); // writeRegister(ACCEL_CONFIG, c & ~0xE0); // Clear self-test bits [7:5] writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, c & ~0x18); // Clear AFS bits [4:3] writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, c | Ascale << 3); // Set full scale range for the accelerometer

// Set accelerometer sample rate configuration // It is possible to get a 4 kHz sample rate from the accelerometer by choosing 1 for // accel_fchoice_b bit [3]; in this case the bandwidth is 1.13 kHz c = readByte(MPU9250_ADDRESS, ACCEL_CONFIG2); writeByte(MPU9250_ADDRESS, ACCEL_CONFIG2, c & ~0x0F); // Clear accel_fchoice_b (bit 3) and A_DLPFG (bits [2:0])
writeByte(MPU9250_ADDRESS, ACCEL_CONFIG2, c | 0x03); // Set accelerometer rate to 1 kHz and bandwidth to 41 Hz

// The accelerometer, gyro, and thermometer are set to 1 kHz sample rates, // but all these rates are further reduced by a factor of 5 to 200 Hz because of the SMPLRT_DIV setting

// Configure Interrupts and Bypass Enable // Set interrupt pin active high, push-pull, hold interrupt pin level HIGH until interrupt cleared, // clear on read of INT_STATUS, and enable I2C_BYPASS_EN so additional chips // can join the I2C bus and all can be controlled by the Arduino as master writeByte(MPU9250_ADDRESS, INT_PIN_CFG, 0x22);
writeByte(MPU9250_ADDRESS, INT_ENABLE, 0x01); // Enable data ready (bit 0) interrupt delay(100); }

// Function which accumulates gyro and accelerometer data after device initialization. It calculates the average // of the at-rest readings and then loads the resulting offsets into accelerometer and gyro bias registers. void calibrateMPU9250(float * dest1, float * dest2) {
uint8_t data[12]; // data array to hold accelerometer and gyro x, y, z, data uint16_t ii, packet_count, fifo_count; int32_t gyro_bias[3] = {0, 0, 0}, accel_bias[3] = {0, 0, 0};

// reset device writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x80); // Write a one to bit 7 reset bit; toggle reset device delay(100);

// get stable time source; Auto select clock source to be PLL gyroscope reference if ready // else use the internal oscillator, bits 2:0 = 001 writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x01);
writeByte(MPU9250_ADDRESS, PWR_MGMT_2, 0x00); delay(200);

// Configure device for bias calculation writeByte(MPU9250_ADDRESS, INT_ENABLE, 0x00); // Disable all interrupts writeByte(MPU9250_ADDRESS, FIFO_EN, 0x00); // Disable FIFO writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x00); // Turn on internal clock source writeByte(MPU9250_ADDRESS, I2C_MST_CTRL, 0x00); // Disable I2C master writeByte(MPU9250_ADDRESS, USER_CTRL, 0x00); // Disable FIFO and I2C master modes writeByte(MPU9250_ADDRESS, USER_CTRL, 0x0C); // Reset FIFO and DMP delay(15);

// Configure MPU6050 gyro and accelerometer for bias calculation writeByte(MPU9250_ADDRESS, CONFIG, 0x01); // Set low-pass filter to 188 Hz writeByte(MPU9250_ADDRESS, SMPLRT_DIV, 0x00); // Set sample rate to 1 kHz writeByte(MPU9250_ADDRESS, GYRO_CONFIG, 0x00); // Set gyro full-scale to 250 degrees per second, maximum sensitivity writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, 0x00); // Set accelerometer full-scale to 2 g, maximum sensitivity

uint16_t gyrosensitivity = 131; // = 131 LSB/degrees/sec uint16_t accelsensitivity = 16384; // = 16384 LSB/g

// Configure FIFO to capture accelerometer and gyro data for bias calculation

writeByte(MPU9250_ADDRESS, USER_CTRL, 0x40); // Enable FIFO
writeByte(MPU9250_ADDRESS, FIFO_EN, 0x78); // Enable gyro and accelerometer sensors for FIFO (max size 512 bytes in MPU-9150) delay(40); // accumulate 40 samples in 40 milliseconds = 480 bytes

// At end of sample accumulation, turn off FIFO sensor read writeByte(MPU9250_ADDRESS, FIFO_EN, 0x00); // Disable gyro and accelerometer sensors for FIFO readBytes(MPU9250_ADDRESS, FIFO_COUNTH, 2, &data[0]); // read FIFO sample count fifo_count = ((uint16_t)data[0] << 8) | data[1]; packet_count = fifo_count/12;// How many sets of full gyro and accelerometer data for averaging

for (ii = 0; ii < packet_count; ii++) { int16_t accel_temp[3] = {0, 0, 0}, gyro_temp[3] = {0, 0, 0}; readBytes(MPU9250_ADDRESS, FIFO_R_W, 12, &data[0]); // read data for averaging accel_temp[0] = (int16_t) (((int16_t)data[0] << 8) | data[1] ) ; // Form signed 16-bit integer for each sample in FIFO accel_temp[1] = (int16_t) (((int16_t)data[2] << 8) | data[3] ) ; accel_temp[2] = (int16_t) (((int16_t)data[4] << 8) | data[5] ) ;
gyro_temp[0] = (int16_t) (((int16_t)data[6] << 8) | data[7] ) ; gyro_temp[1] = (int16_t) (((int16_t)data[8] << 8) | data[9] ) ; gyro_temp[2] = (int16_t) (((int16_t)data[10] << 8) | data[11]) ;

accel_bias[0] += (int32_t) accel_temp[0]; // Sum individual signed 16-bit biases to get accumulated signed 32-bit biases
accel_bias[1] += (int32_t) accel_temp[1];
accel_bias[2] += (int32_t) accel_temp[2];
gyro_bias[0]  += (int32_t) gyro_temp[0];
gyro_bias[1]  += (int32_t) gyro_temp[1];
gyro_bias[2]  += (int32_t) gyro_temp[2];

} accel_bias[0] /= (int32_t) packet_count; // Normalize sums to get average count biases accel_bias[1] /= (int32_t) packet_count; accel_bias[2] /= (int32_t) packet_count; gyro_bias[0] /= (int32_t) packet_count; gyro_bias[1] /= (int32_t) packet_count; gyro_bias[2] /= (int32_t) packet_count;

if(accel_bias[2] > 0L) {accel_bias[2] -= (int32_t) accelsensitivity;} // Remove gravity from the z-axis accelerometer bias calculation else {accel_bias[2] += (int32_t) accelsensitivity;}

// Construct the gyro biases for push to the hardware gyro bias registers, which are reset to zero upon device startup 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 data[1] = (-gyro_bias[0]/4) & 0xFF; // Biases are additive, so change sign on calculated average gyro biases data[2] = (-gyro_bias[1]/4 >> 8) & 0xFF; data[3] = (-gyro_bias[1]/4) & 0xFF; data[4] = (-gyro_bias[2]/4 >> 8) & 0xFF; data[5] = (-gyro_bias[2]/4) & 0xFF;

// Push gyro biases to hardware registers writeByte(MPU9250_ADDRESS, XG_OFFSET_H, data[0]); writeByte(MPU9250_ADDRESS, XG_OFFSET_L, data[1]); writeByte(MPU9250_ADDRESS, YG_OFFSET_H, data[2]); writeByte(MPU9250_ADDRESS, YG_OFFSET_L, data[3]); writeByte(MPU9250_ADDRESS, ZG_OFFSET_H, data[4]); writeByte(MPU9250_ADDRESS, ZG_OFFSET_L, data[5]);

// Output scaled gyro biases for display in the main program dest1[0] = (float) gyro_bias[0]/(float) gyrosensitivity;
dest1[1] = (float) gyro_bias[1]/(float) gyrosensitivity; dest1[2] = (float) gyro_bias[2]/(float) gyrosensitivity;

// Construct the accelerometer biases for push to the hardware accelerometer bias registers. These registers contain // factory trim values which must be added to the calculated accelerometer biases; on boot up these registers will hold // non-zero values. In addition, bit 0 of the lower byte must be preserved since it is used for temperature // compensation calculations. Accelerometer bias registers expect bias input as 2048 LSB per g, so that // the accelerometer biases calculated above must be divided by 8.

int32_t accel_bias_reg[3] = {0, 0, 0}; // A place to hold the factory accelerometer trim biases readBytes(MPU9250_ADDRESS, XA_OFFSET_H, 2, &data[0]); // Read factory accelerometer trim values accel_bias_reg[0] = (int32_t) (((int16_t)data[0] << 8) | data[1]); readBytes(MPU9250_ADDRESS, YA_OFFSET_H, 2, &data[0]); accel_bias_reg[1] = (int32_t) (((int16_t)data[0] << 8) | data[1]); readBytes(MPU9250_ADDRESS, ZA_OFFSET_H, 2, &data[0]); accel_bias_reg[2] = (int32_t) (((int16_t)data[0] << 8) | data[1]);

uint32_t mask = 1uL; // Define mask for temperature compensation bit 0 of lower byte of accelerometer bias registers uint8_t mask_bit[3] = {0, 0, 0}; // Define array to hold mask bit for each accelerometer bias axis

for(ii = 0; ii < 3; ii++) { if((accel_bias_reg[ii] & mask)) mask_bit[ii] = 0x01; // If temperature compensation bit is set, record that fact in mask_bit }

// Construct total accelerometer bias, including calculated average accelerometer bias from above accel_bias_reg[0] -= (accel_bias[0]/8); // Subtract calculated averaged accelerometer bias scaled to 2048 LSB/g (16 g full scale) accel_bias_reg[1] -= (accel_bias[1]/8); accel_bias_reg[2] -= (accel_bias[2]/8);

data[0] = (accel_bias_reg[0] >> 8) & 0xFF; data[1] = (accel_bias_reg[0]) & 0xFF; data[1] = data[1] | mask_bit[0]; // preserve temperature compensation bit when writing back to accelerometer bias registers data[2] = (accel_bias_reg[1] >> 8) & 0xFF; data[3] = (accel_bias_reg[1]) & 0xFF; data[3] = data[3] | mask_bit[1]; // preserve temperature compensation bit when writing back to accelerometer bias registers data[4] = (accel_bias_reg[2] >> 8) & 0xFF; data[5] = (accel_bias_reg[2]) & 0xFF; data[5] = data[5] | mask_bit[2]; // preserve temperature compensation bit when writing back to accelerometer bias registers

// Apparently this is not working for the acceleration biases in the MPU-9250 // Are we handling the temperature correction bit properly? // Push accelerometer biases to hardware registers writeByte(MPU9250_ADDRESS, XA_OFFSET_H, data[0]); writeByte(MPU9250_ADDRESS, XA_OFFSET_L, data[1]); writeByte(MPU9250_ADDRESS, YA_OFFSET_H, data[2]); writeByte(MPU9250_ADDRESS, YA_OFFSET_L, data[3]); writeByte(MPU9250_ADDRESS, ZA_OFFSET_H, data[4]); writeByte(MPU9250_ADDRESS, ZA_OFFSET_L, data[5]);

// Output scaled accelerometer biases for display in the main program dest2[0] = (float)accel_bias[0]/(float)accelsensitivity; dest2[1] = (float)accel_bias[1]/(float)accelsensitivity; dest2[2] = (float)accel_bias[2]/(float)accelsensitivity; }

// Accelerometer and gyroscope self test; check calibration wrt factory settings void MPU9250SelfTest(float * destination) // Should return percent deviation from factory trim values, +/- 14 or less deviation is a pass { uint8_t rawData[6] = {0, 0, 0, 0, 0, 0}; uint8_t selfTest[6]; int16_t gAvg[3], aAvg[3], aSTAvg[3], gSTAvg[3]; float factoryTrim[6]; uint8_t FS = 0;

writeByte(MPU9250_ADDRESS, SMPLRT_DIV, 0x00); // Set gyro sample rate to 1 kHz writeByte(MPU9250_ADDRESS, CONFIG, 0x02); // Set gyro sample rate to 1 kHz and DLPF to 92 Hz writeByte(MPU9250_ADDRESS, GYRO_CONFIG, 1<<FS); // Set full scale range for the gyro to 250 dps writeByte(MPU9250_ADDRESS, ACCEL_CONFIG2, 0x02); // Set accelerometer rate to 1 kHz and bandwidth to 92 Hz writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, 1<<FS); // Set full scale range for the accelerometer to 2 g

for( int ii = 0; ii < 200; ii++) { // get average current values of gyro and acclerometer

readBytes(MPU9250_ADDRESS, ACCEL_XOUT_H, 6, &rawData[0]); // Read the six raw data registers into data array aAvg[0] += (int16_t)(((int16_t)rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value aAvg[1] += (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ;
aAvg[2] += (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ; 

readBytes(MPU9250_ADDRESS, GYRO_XOUT_H, 6, &rawData[0]);       // Read the six raw data registers sequentially into data array

gAvg[0] += (int16_t)(((int16_t)rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value gAvg[1] += (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ;
gAvg[2] += (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ; }

for (int ii =0; ii < 3; ii++) { // Get average of 200 values and store as average current readings aAvg[ii] /= 200; gAvg[ii] /= 200; }

// Configure the accelerometer for self-test writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, 0xE0); // Enable self test on all three axes and set accelerometer range to +/- 2 g writeByte(MPU9250_ADDRESS, GYRO_CONFIG, 0xE0); // Enable self test on all three axes and set gyro range to +/- 250 degrees/s delay(25); // Delay a while to let the device stabilize

for( int ii = 0; ii < 200; ii++) { // get average self-test values of gyro and acclerometer

readBytes(MPU9250_ADDRESS, ACCEL_XOUT_H, 6, &rawData[0]); // Read the six raw data registers into data array aSTAvg[0] += (int16_t)(((int16_t)rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value aSTAvg[1] += (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ;
aSTAvg[2] += (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ; 

readBytes(MPU9250_ADDRESS, GYRO_XOUT_H, 6, &rawData[0]);  // Read the six raw data registers sequentially into data array

gSTAvg[0] += (int16_t)(((int16_t)rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value gSTAvg[1] += (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ;
gSTAvg[2] += (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ; }

for (int ii =0; ii < 3; ii++) { // Get average of 200 values and store as average self-test readings aSTAvg[ii] /= 200; gSTAvg[ii] /= 200; }

// Configure the gyro and accelerometer for normal operation writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, 0x00);
writeByte(MPU9250_ADDRESS, GYRO_CONFIG, 0x00);
delay(25); // Delay a while to let the device stabilize

// Retrieve accelerometer and gyro factory Self-Test Code from USR_Reg selfTest[0] = readByte(MPU9250_ADDRESS, SELF_TEST_X_ACCEL); // X-axis accel self-test results selfTest[1] = readByte(MPU9250_ADDRESS, SELF_TEST_Y_ACCEL); // Y-axis accel self-test results selfTest[2] = readByte(MPU9250_ADDRESS, SELF_TEST_Z_ACCEL); // Z-axis accel self-test results selfTest[3] = readByte(MPU9250_ADDRESS, SELF_TEST_X_GYRO); // X-axis gyro self-test results selfTest[4] = readByte(MPU9250_ADDRESS, SELF_TEST_Y_GYRO); // Y-axis gyro self-test results selfTest[5] = readByte(MPU9250_ADDRESS, SELF_TEST_Z_GYRO); // Z-axis gyro self-test results

// Retrieve factory self-test value from self-test code reads factoryTrim[0] = (float)(2620/1<<FS)(pow( 1.01 , ((float)selfTest[0] - 1.0) )); // FT[Xa] factory trim calculation factoryTrim[1] = (float)(2620/1<<FS)(pow( 1.01 , ((float)selfTest[1] - 1.0) )); // FT[Ya] factory trim calculation factoryTrim[2] = (float)(2620/1<<FS)(pow( 1.01 , ((float)selfTest[2] - 1.0) )); // FT[Za] factory trim calculation factoryTrim[3] = (float)(2620/1<<FS)(pow( 1.01 , ((float)selfTest[3] - 1.0) )); // FT[Xg] factory trim calculation factoryTrim[4] = (float)(2620/1<<FS)(pow( 1.01 , ((float)selfTest[4] - 1.0) )); // FT[Yg] factory trim calculation factoryTrim[5] = (float)(2620/1<<FS)(pow( 1.01 , ((float)selfTest[5] - 1.0) )); // FT[Zg] factory trim calculation

// Report results as a ratio of (STR - FT)/FT; the change from Factory Trim of the Self-Test Response // To get percent, must multiply by 100 for (int i = 0; i < 3; i++) { destination[i] = 100.0((float)(aSTAvg[i] - aAvg[i]))/factoryTrim[i]; // Report percent differences destination[i+3] = 100.0((float)(gSTAvg[i] - gAvg[i]))/factoryTrim[i+3]; // Report percent differences }

}

void writeByte(uint8_t address, uint8_t subAddress, uint8_t data) { SPI_write_register( subAddress, data ); }

uint8_t readByte(uint8_t address, uint8_t subAddress) { uint8_t data; // data will store the register data
data = SPI_read_register( subAddress ); return data; // Return data read from slave register }

void readBytes(uint8_t address, uint8_t subAddress, uint8_t count, uint8_t * dest) { 

digitalWrite( NCS, LOW);

for (int i = 0; i < count; ++i) { uint8_t reg = subAddress + i; SPI.transfer( reg | 0x80 ); // reg | 0x80 to denote read uint8_t read_value = SPI.transfer( 0x00 ); // write 8-bits zero dest[i] = read_value; } digitalWrite( NCS, HIGH); }

natd89 commented 8 years ago

I had a question about your readbytes function. when you store a value in read_value, you send a byte of zeros through SPI.transfer. Are you using SPI.transfer(0x00) just to get a value back, or does transferring 0x00 to the IMU reset the register?

kriswiner commented 8 years ago

Which sketch/file are you referring to? I usually use I2C for my applications, I think I forked another repository that uses SPI in order to someday make this work, but I haven't got around to it.

-----Original Message----- From: natd89 [mailto:notifications@github.com] Sent: August 31, 2016 12:58 PM To: kriswiner/MPU-9250 Subject: Re: [kriswiner/MPU-9250] MPU-9250 and SPI code (#28)

I had a question about your readbytes function. when you store a value in read_value, you send a byte of zeros through SPI.transfer. Are you using SPI.transfer(0x00) just to get a value back, or does transferring 0x00 to the IMU reset the register?

You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub https://github.com/kriswiner/MPU-9250/issues/28#issuecomment-243881650 , or mute the thread https://github.com/notifications/unsubscribe-auth/AGY1qsxRBtFU0NryLA65bugQ9 3PCZSaAks5qldyvgaJpZM4GeAI8 . https://github.com/notifications/beacon/AGY1qt9K8Nz1-kOkHT4C3wvnQl7Zn3Sgks5 qldyvgaJpZM4GeAI8.gif

natd89 commented 8 years ago

I'm referring to the one titled "MPU-9250 and SPI code #28". The readbytes function is at the very bottom of the sketch.

kriswiner commented 8 years ago

No idea, this is not my code (at least not some of it), someone has hacked it and posted it here apparently.

-----Original Message----- From: natd89 [mailto:notifications@github.com] Sent: August 31, 2016 1:24 PM To: kriswiner/MPU-9250 Cc: Kris Winer; Comment Subject: Re: [kriswiner/MPU-9250] MPU-9250 and SPI code (#28)

I'm referring to the one titled "MPU-9250 and SPI code #28 https://github.com/kriswiner/MPU-9250/issues/28 ". The readbytes function is at the very bottom of the sketch.

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brianc118 commented 7 years ago

@natd89 For interfacing the MPU-9250 with Arduino I suggest you use https://github.com/brianc118/MPU9250/.

And yes, SPI.transfer() is reading 1 byte of data but also sending one byte of data to the slave concurrently. SPI is a bidirectional protocol. i.e. for every byte sent, one byte is received.

Someone should close this issue.

bmsrao commented 4 years ago

hi , great work... is it possible to implement with out using ARDUINO board.. i mean want to implement on AT90USB1286 8-bit microcontroller: is it possible?.. if your answer is yes..please tell me how?

kriswiner commented 4 years ago

I have never used this MCU but I would think its memory and speed make it unsuitable for this kind of application. Why not something more appropriate like this https://www.tindie.com/products/tleracorp/ladybug-stm32l432-development-board/ open source design?

On Wed, Jun 10, 2020 at 5:16 AM bmsrao notifications@github.com wrote:

hi , great work... is it possible to implement with out using ARDUINO board.. i mean want to implement on AT90USB1286 8-bit microcontroller: is it possible?.. if your answer is yes..please tell me how?

— You are receiving this because you commented. Reply to this email directly, view it on GitHub https://github.com/kriswiner/MPU9250/issues/28#issuecomment-641964543, or unsubscribe https://github.com/notifications/unsubscribe-auth/ABTDLKRNXK5VN4DCO56F4GDRV52SRANCNFSM4BTYAI6A .