Revision 0:76dc2aad77bc, committed 2016-10-05

Comitter:

elessair

Date:

Wed Oct 05 10:33:45 2016 +0000

Child:

1:c27bb1a0deca

Commit message:

fork of MPU9250AHRS from Kris Winer

Changed in this revision

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/MPU9250.cpp	Wed Oct 05 10:33:45 2016 +0000
@@ -0,0 +1,300 @@
+
+#include <mbed.h>
+#include "MPU9250.h"
+
+
+mpu9250::mpu9250(PinName _sda, PinName _scl) : i2c(_sda, _scl)
+{
+    i2c.frequency(400000);
+}
+
+
+void mpu9250::writeByte(uint8_t address, uint8_t subAddress, uint8_t data)
+{
+    char data_write[2];
+    data_write[0] = subAddress;
+    data_write[1] = data;
+    i2c.write(address, data_write, 2, 0);
+}
+
+char mpu9250::readByte(uint8_t address, uint8_t subAddress)
+{
+    char data[1]; // `data` will store the register data
+    char data_write[1];
+    data_write[0] = subAddress;
+    i2c.write(address, data_write, 1, 1); // no stop
+    i2c.read(address, data, 1, 0);
+    return data[0];
+}
+
+void mpu9250::readBytes(uint8_t address, uint8_t subAddress, uint8_t count, uint8_t * dest)
+{
+    char data[14];
+    char data_write[1];
+    data_write[0] = subAddress;
+    i2c.write(address, data_write, 1, 1); // no stop
+    i2c.read(address, data, count, 0);
+    for(int ii = 0; ii < count; ii++) {
+        dest[ii] = data[ii];
+    }
+}
+
+bool mpu9250::alive()
+{
+    if(readByte(MPU9250_ADDRESS, WHO_AM_I_MPU9250) == 0x71)
+        return true;
+    else
+        return false;
+}
+
+void mpu9250::getGres(uint8_t Gscale)
+{
+    switch (Gscale) {
+        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 mpu9250::getAres(uint8_t Ascale)
+{
+    switch (Ascale) {
+        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 mpu9250::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)(((int16_t)rawData[0] << 8) | rawData[1]) ;  // Turn the MSB and LSB into a signed 16-bit value
+    destination[1] = (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ;
+    destination[2] = (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ;
+}
+
+void mpu9250::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)(((int16_t)rawData[0] << 8) | rawData[1]) ;  // Turn the MSB and LSB into a signed 16-bit value
+    destination[1] = (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ;
+    destination[2] = (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ;
+}
+
+void mpu9250::readTempData(int16_t * destination)
+{
+    uint8_t rawData[2];
+    readBytes(MPU9250_ADDRESS, TEMP_OUT_H, 2, &rawData[0]);  // Read the two raw data registers sequentially into data array
+    destination[0] = (int16_t)(((int16_t)rawData[0]) << 8 | rawData[1]) ;  // Turn the MSB and LSB into a 16-bit value
+}
+
+void mpu9250::readAll(int16_t * destinationAcc, int16_t * destinationGyro, int16_t * destinationTemp)
+{
+    readAccelData(destinationAcc);  // Read the x/y/z adc values
+    readGyroData(destinationGyro);  // Read the x/y/z adc values
+    readTempData(destinationTemp);  // Read the adc values
+}
+
+void mpu9250::ReadConvertAll(float * destinationAcc, float * destinationGyro, float * destinationTemp)
+{
+    int16_t AccRead[3];
+    int16_t GyroRead[3];
+    int16_t TempRead[1];
+
+    readAll(AccRead,GyroRead,TempRead);
+
+    destinationAcc[0] = -1000*((float)AccRead[1]*aRes - accelBias[1]);  // get actual g value, this depends on scale being set
+    destinationAcc[1] = -1000*((float)AccRead[0]*aRes - accelBias[0]);
+    destinationAcc[2] = 1000*((float)AccRead[2]*aRes - accelBias[2]);
+
+    destinationGyro[0] = (float)GyroRead[0]*gRes - gyroBias[0];  // get actual gyro value, this depends on scale being set
+    destinationGyro[1] = (float)GyroRead[1]*gRes - gyroBias[1];
+    destinationGyro[2] = (float)GyroRead[2]*gRes - gyroBias[2];
+
+    destinationTemp[0] = ((float) TempRead[0]) / 333.87f + 21.0f; // Temperature in degrees Centigrade
+}
+
+void mpu9250::resetMPU9250()
+{
+    writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x80); // Write a one to bit 7 reset bit; toggle reset device
+    wait(0.1);
+}
+
+void mpu9250::initMPU9250(uint8_t Ascale,uint8_t Gscale)
+{
+    resetMPU9250();
+    wait(0.2);
+
+    writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x00); // Clear sleep mode bit (6), enable all sensors
+    wait(0.1); // Delay 100 ms for PLL to get established on x-axis gyro; should check for PLL ready interrupt
+
+    writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x01);  // Set clock source to be PLL with x-axis gyroscope reference, bits 2:0 = 001
+    writeByte(MPU9250_ADDRESS, CONFIG, 0x03);
+
+    writeByte(MPU9250_ADDRESS, SMPLRT_DIV, 0x04);  // Use a 200 Hz rate; the same rate set in CONFIG above
+
+    uint8_t c =  readByte(MPU9250_ADDRESS, GYRO_CONFIG);
+    writeByte(MPU9250_ADDRESS, GYRO_CONFIG, c & ~0xE0); // Clear self-test bits [7:5]
+    writeByte(MPU9250_ADDRESS, GYRO_CONFIG, c & ~0x18); // Clear AFS bits [4:3]
+    writeByte(MPU9250_ADDRESS, GYRO_CONFIG, c | Gscale); // Set full scale range for the gyro
+
+    c =  readByte(MPU9250_ADDRESS, ACCEL_CONFIG);
+    writeByte(MPU9250_ADDRESS, 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); // Set full scale range for the accelerometer
+
+    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
+
+    //  writeByte(MPU9250_ADDRESS, INT_PIN_CFG, 0x22);
+    //  writeByte(MPU9250_ADDRESS, INT_ENABLE, 0x01);  // Enable data ready (bit 0) interrupt
+
+    getAres(Ascale); // Get accelerometer sensitivity
+    getGres(Gscale); // Get gyro sensitivity
+
+    calibrateMPU9250(gyroBias, accelBias); // Calibrate gyro and accelerometers, load biases in bias registers
+}
+
+
+void mpu9250::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};
+
+    writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x80); // Write a one to bit 7 reset bit; toggle reset device
+    wait(0.1);
+
+    writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x01);
+    writeByte(MPU9250_ADDRESS, PWR_MGMT_2, 0x00);
+    wait(0.2);
+
+    // 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
+    wait(0.015);
+
+    // Configure MPU9250 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-9250)
+    wait(0.04); // accumulate 40 samples in 80 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;
+
+    dest1[0] = (float) gyro_bias[0]/(float) gyrosensitivity; // construct gyro bias in deg/s for later manual subtraction
+    dest1[1] = (float) gyro_bias[1]/(float) gyrosensitivity;
+    dest1[2] = (float) gyro_bias[2]/(float) gyrosensitivity;
+
+    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] = (int16_t) ((int16_t)data[0] << 8) | data[1];
+    readBytes(MPU9250_ADDRESS, YA_OFFSET_H, 2, &data[0]);
+    accel_bias_reg[1] = (int16_t) ((int16_t)data[0] << 8) | data[1];
+    readBytes(MPU9250_ADDRESS, ZA_OFFSET_H, 2, &data[0]);
+    accel_bias_reg[2] = (int16_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
+
+    // Output scaled accelerometer biases for manual subtraction 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;
+}
+

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/MPU9250.h	Wed Oct 05 10:33:45 2016 +0000
@@ -0,0 +1,174 @@
+#ifndef MPU9250_H
+#define MPU9250_H
+
+#include "mbed.h"
+#include "math.h"
+
+
+class mpu9250
+{
+    I2C i2c;
+public:
+    mpu9250(PinName _sda, PinName _scl);
+    void writeByte(uint8_t address, uint8_t subAddress, uint8_t data);
+    char readByte(uint8_t address, uint8_t subAddress);
+    void readBytes(uint8_t address, uint8_t subAddress, uint8_t count, uint8_t * dest);
+    bool alive();
+    void getGres(uint8_t Gscale);
+    void getAres(uint8_t Ascale);
+    void readAccelData(int16_t * destination) ;
+    void readGyroData(int16_t * destination) ;
+    void readTempData(int16_t * destination);
+    void readAll(int16_t * destinationAcc, int16_t * destinationGyro, int16_t * destinationTemp);
+    void ReadConvertAll(float * destinationAcc, float * destinationGyro, float * destinationTemp);
+    void resetMPU9250() ;
+    void initMPU9250(uint8_t Ascale, uint8_t Gscale);
+    void calibrateMPU9250(float * dest1, float * dest2);
+
+    float aRes, gRes;      // scale resolutions per LSB for the sensors
+    float gyroBias[3];
+    float accelBias[3]; // Bias corrections for gyro and accelerometer
+
+
+private:
+    PinName _SDA_pin;
+    PinName _SCL_pin;
+    float _error;
+};
+
+#endif
+
+
+#define SELF_TEST_X_GYRO 0x00
+#define SELF_TEST_Y_GYRO 0x01
+#define SELF_TEST_Z_GYRO 0x02
+#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
+#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
+
+#define GFS_250DPS       0x00
+#define GFS_500DPS       0x08
+#define GFS_1000DPS      0x10
+#define GFS_2000DPS      0x18
+#define AFS_2G           0x00
+#define AFS_4G           0x08
+#define AFS_8G           0x10
+#define AFS_16G          0x18
+
+#define ADO 0
+#if ADO
+#define MPU9250_ADDRESS 0x69<<1  // Device address when ADO = 1
+#else
+#define MPU9250_ADDRESS 0x68<<1  // Device address when ADO = 0
+#endif
+
+