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mod
Dependencies: ST_401_84MHZ mbed
Fork of MPU9250AHRS by
MPU9250.h
- Committer:
- nikitamere
- Date:
- 2016-09-16
- Revision:
- 3:f1893b5610f7
- Parent:
- 2:4e59a37182df
File content as of revision 3:f1893b5610f7:
#ifndef MPU9250_H #define MPU9250_H #include "mbed.h" #include "math.h" // 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<<1 #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 //mbed uses the eight-bit device address, so shift seven-bit addresses left by one! #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 // 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 }; uint8_t Ascale = AFS_2G; // AFS_2G, AFS_4G, AFS_8G, AFS_16G uint8_t Gscale = GFS_250DPS; // GFS_250DPS, GFS_500DPS, GFS_1000DPS, GFS_2000DPS uint8_t Mscale = MFS_16BITS; // MFS_14BITS or MFS_16BITS, 14-bit or 16-bit magnetometer resolution uint8_t Mmode = 0x06; // Either 8 Hz 0x02) or 100 Hz (0x06) magnetometer data ODR float aRes, gRes, mRes; // scale resolutions per LSB for the sensors //Set up I2C, (SDA,SCL) I2C i2c(I2C_SDA, I2C_SCL); DigitalOut myled(LED1); // Pin definitions int intPin = 12; // These can be changed, 2 and 3 are the Arduinos ext int pins 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 float ax, ay, az, gx, gy, gz, mx, my, mz; // variables to hold latest sensor data values int16_t tempCount; // Stores the real internal chip temperature in degrees Celsius float temperature; float SelfTest[6]; int delt_t = 0; // used to control display output rate int count = 0; // used to control display output rate // parameters for 6 DoF sensor fusion calculations float PI = 3.14159265358979323846f; 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 float beta = sqrt(3.0f / 4.0f) * GyroMeasError; // compute beta float GyroMeasDrift = PI * (1.0f / 180.0f); // gyroscope measurement drift in rad/s/s (start at 0.0 deg/s/s) 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 6.0f * 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 float pitch, yaw, roll; float deltat = 0.0f; // integration interval for both filter schemes int lastUpdate = 0, firstUpdate = 0, Now = 0; // used to calculate integration interval // used to calculate integration interval 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 class MPU9250 { protected: public: //=================================================================================================================== //====== Set of useful function to access acceleratio, gyroscope, and temperature data //=================================================================================================================== void 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 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 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]; } } 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 = 10.0*4219.0/8190.0; // Proper scale to return milliGauss break; case MFS_16BITS: mRes = 10.0*4219.0/32760.0; // 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)(((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 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 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)(((int16_t)rawData[1] << 8) | rawData[0]); // Turn the MSB and LSB into a signed 16-bit value destination[1] = (int16_t)(((int16_t)rawData[3] << 8) | rawData[2]) ; // Data stored as little Endian destination[2] = (int16_t)(((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)(((int16_t)rawData[0]) << 8 | rawData[1]) ; // Turn the MSB and LSB into a 16-bit value } void resetMPU9250() { // reset device writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x80); // Write a one to bit 7 reset bit; toggle reset device wait(0.1); } 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 wait(0.01); writeByte(AK8963_ADDRESS, AK8963_CNTL, 0x0F); // Enter Fuse ROM access mode wait(0.01); readBytes(AK8963_ADDRESS, AK8963_ASAX, 3, &rawData[0]); // Read the x-, y-, and z-axis calibration values destination[0] = (float)(rawData[0] - 128)/256.0f + 1.0f; // Return x-axis sensitivity adjustment values, etc. destination[1] = (float)(rawData[1] - 128)/256.0f + 1.0f; destination[2] = (float)(rawData[2] - 128)/256.0f + 1.0f; writeByte(AK8963_ADDRESS, AK8963_CNTL, 0x00); // Power down magnetometer wait(0.01); // 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 wait(0.01); } void initMPU9250() { // Initialize MPU9250 device // wake up device 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 // get stable time source writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x01); // Set clock source to be PLL with x-axis gyroscope reference, bits 2:0 = 001 // Configure Gyro and Accelerometer // Disable FSYNC and set accelerometer and gyro bandwidth to 44 and 42 Hz, respectively; // DLPF_CFG = bits 2:0 = 010; this sets the sample rate at 1 kHz for both // Maximum delay is 4.9 ms which is just over a 200 Hz maximum rate 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; the same rate set 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); 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 << 3); // Set full scale range for the gyro // Set accelerometer configuration 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 << 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, and clear on read of INT_STATUS, 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 } // 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, reset all registers, clear gyro and accelerometer bias registers writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x80); // Write a one to bit 7 reset bit; toggle reset device wait(0.1); // get stable time source // Set clock source to be PLL with x-axis gyroscope reference, bits 2:0 = 001 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; /// 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]); */ 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; // 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] = (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 // 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 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; } // 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 wait(0.25); // 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); wait(0.25); // 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 } } // 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; } }; class IMU { public: void init(bool debug) { this->debug = debug; i2c.frequency(400000); // use fast (400 kHz) I2C Serial pc(USBTX,USBRX); pc.baud(38400); pc.printf("CPU SystemCoreClock is %d Hz\r\n", SystemCoreClock); t.start(); // Read the WHO_AM_I register, this is a good test of communication uint8_t whoami = mpu9250.readByte(MPU9250_ADDRESS, WHO_AM_I_MPU9250); // Read WHO_AM_I register for MPU-9250 pc.printf("I AM 0x%x\n\r", whoami); pc.printf("I SHOULD BE 0x71\n\r"); if (whoami == 0x71) { // WHO_AM_I should always be 0x68 pc.printf("MPU9250 WHO_AM_I is 0x%x\n\r", whoami); pc.printf("MPU9250 is online...\n\r"); sprintf(buffer, "0x%x", whoami); wait(1); mpu9250.resetMPU9250(); // Reset registers to default in preparation for device calibration mpu9250.MPU9250SelfTest(SelfTest); // Start by performing self test and reporting values if (debug) { pc.printf("x-axis self test: acceleration trim within : %f % of factory value\n\r", SelfTest[0]); pc.printf("y-axis self test: acceleration trim within : %f % of factory value\n\r", SelfTest[1]); pc.printf("z-axis self test: acceleration trim within : %f % of factory value\n\r", SelfTest[2]); pc.printf("x-axis self test: gyration trim within : %f % of factory value\n\r", SelfTest[3]); pc.printf("y-axis self test: gyration trim within : %f % of factory value\n\r", SelfTest[4]); pc.printf("z-axis self test: gyration trim within : %f % of factory value\n\r", SelfTest[5]); } mpu9250.calibrateMPU9250(gyroBias, accelBias); // Calibrate gyro and accelerometers, load biases in bias registers if (debug) { pc.printf("x gyro bias = %f\n\r", gyroBias[0]); pc.printf("y gyro bias = %f\n\r", gyroBias[1]); pc.printf("z gyro bias = %f\n\r", gyroBias[2]); pc.printf("x accel bias = %f\n\r", accelBias[0]); pc.printf("y accel bias = %f\n\r", accelBias[1]); pc.printf("z accel bias = %f\n\r", accelBias[2]); } wait(2); mpu9250.initMPU9250(); pc.printf("MPU9250 initialized for active data mode....\n\r"); // Initialize device for active mode read of acclerometer, gyroscope, and temperature mpu9250.initAK8963(magCalibration); pc.printf("AK8963 initialized for active data mode....\n\r"); // Initialize device for active mode read of magnetometer if (debug) pc.printf("Accelerometer full-scale range = %f g\n\r", 2.0f*(float)(1<<Ascale)); if (debug) pc.printf("Gyroscope full-scale range = %f deg/s\n\r", 250.0f*(float)(1<<Gscale)); if(Mscale == 0 && debug) pc.printf("Magnetometer resolution = 14 bits\n\r"); if(Mscale == 1 && debug) pc.printf("Magnetometer resolution = 16 bits\n\r"); if(Mmode == 2 && debug) pc.printf("Magnetometer ODR = 8 Hz\n\r"); if(Mmode == 6 && debug) pc.printf("Magnetometer ODR = 100 Hz\n\r"); wait(1); } else { pc.printf("Could not connect to MPU9250: \n\r"); pc.printf("%#x \n", whoami); while(1) ; // Loop forever if communication doesn't happen } mpu9250.getAres(); // Get accelerometer sensitivity mpu9250.getGres(); // Get gyro sensitivity mpu9250.getMres(); // Get magnetometer sensitivity if (debug) pc.printf("Accelerometer sensitivity is %f LSB/g \n\r", 1.0f/aRes); if (debug) pc.printf("Gyroscope sensitivity is %f LSB/deg/s \n\r", 1.0f/gRes); if (debug) pc.printf("Magnetometer sensitivity is %f LSB/G \n\r", 1.0f/mRes); 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 yawZero=0; rollZero=0; pitchZero=0; } void update() { // If intPin goes high, all data registers have new data if(mpu9250.readByte(MPU9250_ADDRESS, INT_STATUS) & 0x01) { // On interrupt, check if data ready interrupt mpu9250.readAccelData(accelCount); // Read the x/y/z adc values // 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]; mpu9250.readGyroData(gyroCount); // Read the x/y/z adc values // Calculate the gyro value into actual degrees per second gx = (float)gyroCount[0]*gRes - gyroBias[0]; // get actual gyro value, this depends on scale being set gy = (float)gyroCount[1]*gRes - gyroBias[1]; gz = (float)gyroCount[2]*gRes - gyroBias[2]; mpu9250.readMagData(magCount); // Read the x/y/z adc values // 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 = t.read_us(); deltat = (float)((Now - lastUpdate)/1000000.0f) ; // set integration time by time elapsed since last filter update lastUpdate = Now; sum += deltat; sumCount++; // if(lastUpdate - firstUpdate > 10000000.0f) { // beta = 0.04; // decrease filter gain after stabilized // zeta = 0.015; // increasey bias drift gain after stabilized // } // Pass gyro rate as rad/s //mpu9250.MadgwickQuaternionUpdate(ax, ay, az, gx*PI/180.0f, gy*PI/180.0f, gz*PI/180.0f, my, mx, mz); mpu9250.MahonyQuaternionUpdate(ax, ay, az, gx*PI/180.0f, gy*PI/180.0f, gz*PI/180.0f, my, mx, mz); } void setZero() { rollZero = getRollRelative(); pitchZero = getPitchRelative(); yawZero = getYawRelative(); } void updateRollAbsolute() { 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]); roll *= 180.0f / PI; } void updatePitchAbsolute() { pitch = -asin(2.0f * (q[1] * q[3] - q[0] * q[2])); pitch *= 180.0f / PI; } void updateYawAbsolute() { 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]); yaw *= 180.0f / PI; } float getRollRelative() { float res = roll - rollZero; if (debug) printf("[d] Roll relative value: %f\n\r", res); return res; } float getPitchRelative() { float res = pitch - pitchZero; if (debug) printf("[d] Pitch relative value: %f\n\r", res); return res; } float getYawRelative() { float res = yaw - yawZero; if (debug) printf("[d] Yaw relative value: %f\n\r", res); return res; } private: float rollZero, pitchZero, yawZero; bool debug; Timer t; float sum; uint32_t sumCount; char buffer[14]; MPU9250 mpu9250; }; #endif