Kris Winer
/
MPU9250AHRS_nRF52832
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Dependencies: BLE_API mbed-src nRF51822
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MPU9250.h
00001 #ifndef MPU9250_H 00002 #define MPU9250_H 00003 00004 #include "mbed.h" 00005 #include "math.h" 00006 00007 // 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 00008 // above document; the MPU9250 and MPU9150 are virtually identical but the latter has a different register map 00009 // 00010 //Magnetometer Registers 00011 #define AK8963_ADDRESS 0x0C<<1 00012 #define WHO_AM_I_AK8963 0x00 // should return 0x48 00013 #define INFO 0x01 00014 #define AK8963_ST1 0x02 // data ready status bit 0 00015 #define AK8963_XOUT_L 0x03 // data 00016 #define AK8963_XOUT_H 0x04 00017 #define AK8963_YOUT_L 0x05 00018 #define AK8963_YOUT_H 0x06 00019 #define AK8963_ZOUT_L 0x07 00020 #define AK8963_ZOUT_H 0x08 00021 #define AK8963_ST2 0x09 // Data overflow bit 3 and data read error status bit 2 00022 #define AK8963_CNTL 0x0A // Power down (0000), single-measurement (0001), self-test (1000) and Fuse ROM (1111) modes on bits 3:0 00023 #define AK8963_ASTC 0x0C // Self test control 00024 #define AK8963_I2CDIS 0x0F // I2C disable 00025 #define AK8963_ASAX 0x10 // Fuse ROM x-axis sensitivity adjustment value 00026 #define AK8963_ASAY 0x11 // Fuse ROM y-axis sensitivity adjustment value 00027 #define AK8963_ASAZ 0x12 // Fuse ROM z-axis sensitivity adjustment value 00028 00029 #define SELF_TEST_X_GYRO 0x00 00030 #define SELF_TEST_Y_GYRO 0x01 00031 #define SELF_TEST_Z_GYRO 0x02 00032 00033 /*#define X_FINE_GAIN 0x03 // [7:0] fine gain 00034 #define Y_FINE_GAIN 0x04 00035 #define Z_FINE_GAIN 0x05 00036 #define XA_OFFSET_H 0x06 // User-defined trim values for accelerometer 00037 #define XA_OFFSET_L_TC 0x07 00038 #define YA_OFFSET_H 0x08 00039 #define YA_OFFSET_L_TC 0x09 00040 #define ZA_OFFSET_H 0x0A 00041 #define ZA_OFFSET_L_TC 0x0B */ 00042 00043 #define SELF_TEST_X_ACCEL 0x0D 00044 #define SELF_TEST_Y_ACCEL 0x0E 00045 #define SELF_TEST_Z_ACCEL 0x0F 00046 00047 #define SELF_TEST_A 0x10 00048 00049 #define XG_OFFSET_H 0x13 // User-defined trim values for gyroscope 00050 #define XG_OFFSET_L 0x14 00051 #define YG_OFFSET_H 0x15 00052 #define YG_OFFSET_L 0x16 00053 #define ZG_OFFSET_H 0x17 00054 #define ZG_OFFSET_L 0x18 00055 #define SMPLRT_DIV 0x19 00056 #define CONFIG 0x1A 00057 #define GYRO_CONFIG 0x1B 00058 #define ACCEL_CONFIG 0x1C 00059 #define ACCEL_CONFIG2 0x1D 00060 #define LP_ACCEL_ODR 0x1E 00061 #define WOM_THR 0x1F 00062 00063 #define MOT_DUR 0x20 // Duration counter threshold for motion interrupt generation, 1 kHz rate, LSB = 1 ms 00064 #define ZMOT_THR 0x21 // Zero-motion detection threshold bits [7:0] 00065 #define ZRMOT_DUR 0x22 // Duration counter threshold for zero motion interrupt generation, 16 Hz rate, LSB = 64 ms 00066 00067 #define FIFO_EN 0x23 00068 #define I2C_MST_CTRL 0x24 00069 #define I2C_SLV0_ADDR 0x25 00070 #define I2C_SLV0_REG 0x26 00071 #define I2C_SLV0_CTRL 0x27 00072 #define I2C_SLV1_ADDR 0x28 00073 #define I2C_SLV1_REG 0x29 00074 #define I2C_SLV1_CTRL 0x2A 00075 #define I2C_SLV2_ADDR 0x2B 00076 #define I2C_SLV2_REG 0x2C 00077 #define I2C_SLV2_CTRL 0x2D 00078 #define I2C_SLV3_ADDR 0x2E 00079 #define I2C_SLV3_REG 0x2F 00080 #define I2C_SLV3_CTRL 0x30 00081 #define I2C_SLV4_ADDR 0x31 00082 #define I2C_SLV4_REG 0x32 00083 #define I2C_SLV4_DO 0x33 00084 #define I2C_SLV4_CTRL 0x34 00085 #define I2C_SLV4_DI 0x35 00086 #define I2C_MST_STATUS 0x36 00087 #define INT_PIN_CFG 0x37 00088 #define INT_ENABLE 0x38 00089 #define DMP_INT_STATUS 0x39 // Check DMP interrupt 00090 #define INT_STATUS 0x3A 00091 #define ACCEL_XOUT_H 0x3B 00092 #define ACCEL_XOUT_L 0x3C 00093 #define ACCEL_YOUT_H 0x3D 00094 #define ACCEL_YOUT_L 0x3E 00095 #define ACCEL_ZOUT_H 0x3F 00096 #define ACCEL_ZOUT_L 0x40 00097 #define TEMP_OUT_H 0x41 00098 #define TEMP_OUT_L 0x42 00099 #define GYRO_XOUT_H 0x43 00100 #define GYRO_XOUT_L 0x44 00101 #define GYRO_YOUT_H 0x45 00102 #define GYRO_YOUT_L 0x46 00103 #define GYRO_ZOUT_H 0x47 00104 #define GYRO_ZOUT_L 0x48 00105 #define EXT_SENS_DATA_00 0x49 00106 #define EXT_SENS_DATA_01 0x4A 00107 #define EXT_SENS_DATA_02 0x4B 00108 #define EXT_SENS_DATA_03 0x4C 00109 #define EXT_SENS_DATA_04 0x4D 00110 #define EXT_SENS_DATA_05 0x4E 00111 #define EXT_SENS_DATA_06 0x4F 00112 #define EXT_SENS_DATA_07 0x50 00113 #define EXT_SENS_DATA_08 0x51 00114 #define EXT_SENS_DATA_09 0x52 00115 #define EXT_SENS_DATA_10 0x53 00116 #define EXT_SENS_DATA_11 0x54 00117 #define EXT_SENS_DATA_12 0x55 00118 #define EXT_SENS_DATA_13 0x56 00119 #define EXT_SENS_DATA_14 0x57 00120 #define EXT_SENS_DATA_15 0x58 00121 #define EXT_SENS_DATA_16 0x59 00122 #define EXT_SENS_DATA_17 0x5A 00123 #define EXT_SENS_DATA_18 0x5B 00124 #define EXT_SENS_DATA_19 0x5C 00125 #define EXT_SENS_DATA_20 0x5D 00126 #define EXT_SENS_DATA_21 0x5E 00127 #define EXT_SENS_DATA_22 0x5F 00128 #define EXT_SENS_DATA_23 0x60 00129 #define MOT_DETECT_STATUS 0x61 00130 #define I2C_SLV0_DO 0x63 00131 #define I2C_SLV1_DO 0x64 00132 #define I2C_SLV2_DO 0x65 00133 #define I2C_SLV3_DO 0x66 00134 #define I2C_MST_DELAY_CTRL 0x67 00135 #define SIGNAL_PATH_RESET 0x68 00136 #define MOT_DETECT_CTRL 0x69 00137 #define USER_CTRL 0x6A // Bit 7 enable DMP, bit 3 reset DMP 00138 #define PWR_MGMT_1 0x6B // Device defaults to the SLEEP mode 00139 #define PWR_MGMT_2 0x6C 00140 #define DMP_BANK 0x6D // Activates a specific bank in the DMP 00141 #define DMP_RW_PNT 0x6E // Set read/write pointer to a specific start address in specified DMP bank 00142 #define DMP_REG 0x6F // Register in DMP from which to read or to which to write 00143 #define DMP_REG_1 0x70 00144 #define DMP_REG_2 0x71 00145 #define FIFO_COUNTH 0x72 00146 #define FIFO_COUNTL 0x73 00147 #define FIFO_R_W 0x74 00148 #define WHO_AM_I_MPU9250 0x75 // Should return 0x71 00149 #define XA_OFFSET_H 0x77 00150 #define XA_OFFSET_L 0x78 00151 #define YA_OFFSET_H 0x7A 00152 #define YA_OFFSET_L 0x7B 00153 #define ZA_OFFSET_H 0x7D 00154 #define ZA_OFFSET_L 0x7E 00155 00156 // Using the MSENSR-9250 breakout board, ADO is set to 0 00157 // Seven-bit device address is 110100 for ADO = 0 and 110101 for ADO = 1 00158 //mbed uses the eight-bit device address, so shift seven-bit addresses left by one! 00159 #define ADO 0 00160 #if ADO 00161 #define MPU9250_ADDRESS 0x69<<1 // Device address when ADO = 1 00162 #else 00163 #define MPU9250_ADDRESS 0x68<<1 // Device address when ADO = 0 00164 #endif 00165 00166 // Set initial input parameters 00167 enum Ascale { 00168 AFS_2G = 0, 00169 AFS_4G, 00170 AFS_8G, 00171 AFS_16G 00172 }; 00173 00174 enum Gscale { 00175 GFS_250DPS = 0, 00176 GFS_500DPS, 00177 GFS_1000DPS, 00178 GFS_2000DPS 00179 }; 00180 00181 enum Mscale { 00182 MFS_14BITS = 0, // 0.6 mG per LSB 00183 MFS_16BITS // 0.15 mG per LSB 00184 }; 00185 00186 uint8_t Ascale = AFS_2G; // AFS_2G, AFS_4G, AFS_8G, AFS_16G 00187 uint8_t Gscale = GFS_250DPS; // GFS_250DPS, GFS_500DPS, GFS_1000DPS, GFS_2000DPS 00188 uint8_t Mscale = MFS_16BITS; // MFS_14BITS or MFS_16BITS, 14-bit or 16-bit magnetometer resolution 00189 uint8_t Mmode = 0x06; // Either 8 Hz 0x02) or 100 Hz (0x06) magnetometer data ODR 00190 float aRes, gRes, mRes; // scale resolutions per LSB for the sensors 00191 00192 //Set up I2C, (SDA,SCL) 00193 //I2C i2c(I2C_SDA, I2C_SCL); 00194 //I2C i2c(P0_0, P0_1); // nRF51 FC 00195 //I2C i2c(P0_6, P0_7); // nRF52 QFN dev board 00196 I2C i2c(P0_6, P0_5); // nRF52 CIAA dev board 00197 00198 //DigitalOut myled(P0_19); // mbed kit 00199 //DigitalOut myled(P0_18); // nRF51822 module 00200 DigitalOut myled(P0_24); // nRF52832 module 00201 00202 // Pin definitions 00203 bool newData = false; 00204 bool newMagData = false; 00205 00206 int16_t MPU9250Data[7]; // used to read all 14 bytes at once from the MPU9250 accel/gyro 00207 int16_t accelCount[3]; // Stores the 16-bit signed accelerometer sensor output 00208 int16_t gyroCount[3]; // Stores the 16-bit signed gyro sensor output 00209 int16_t magCount[3]; // Stores the 16-bit signed magnetometer sensor output 00210 float magCalibration[3] = {0, 0, 0}, magbias[3] = {0, 0, 0}; // Factory mag calibration and mag bias 00211 float gyroBias[3] = {0, 0, 0}, accelBias[3] = {0, 0, 0}, magBias[3] = {0, 0, 0}, magScale[3] = {0, 0, 0}; // Bias corrections for gyro and accelerometer 00212 float ax, ay, az, gx, gy, gz, mx, my, mz; // variables to hold latest sensor data values 00213 int16_t tempCount; // Stores the real internal chip temperature in degrees Celsius 00214 float temperature; 00215 float SelfTest[6]; 00216 00217 int delt_t = 0; // used to control display output rate 00218 int count = 0; // used to control display output rate 00219 00220 // parameters for 6 DoF sensor fusion calculations 00221 float PI = 3.14159265358979323846f; 00222 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 00223 float beta = sqrt(3.0f / 4.0f) * GyroMeasError; // compute beta 00224 float GyroMeasDrift = PI * (1.0f / 180.0f); // gyroscope measurement drift in rad/s/s (start at 0.0 deg/s/s) 00225 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 00226 #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 00227 #define Ki 0.0f 00228 00229 float pitch, yaw, roll; 00230 float deltat = 0.0f; // integration interval for both filter schemes 00231 int lastUpdate = 0, firstUpdate = 0, Now = 0; // used to calculate integration interval // used to calculate integration interval 00232 float q[4] = {1.0f, 0.0f, 0.0f, 0.0f}; // vector to hold quaternion 00233 float eInt[3] = {0.0f, 0.0f, 0.0f}; // vector to hold integral error for Mahony method 00234 00235 class MPU9250 { 00236 00237 protected: 00238 00239 public: 00240 //=================================================================================================================== 00241 //====== Set of useful function to access acceleratio, gyroscope, and temperature data 00242 //=================================================================================================================== 00243 00244 void writeByte(uint8_t address, uint8_t subAddress, uint8_t data) 00245 { 00246 char data_write[2]; 00247 data_write[0] = subAddress; 00248 data_write[1] = data; 00249 i2c.write(address, data_write, 2, 0); 00250 } 00251 00252 char readByte(uint8_t address, uint8_t subAddress) 00253 { 00254 char data[1]; // `data` will store the register data 00255 char data_write[1]; 00256 data_write[0] = subAddress; 00257 i2c.write(address, data_write, 1, 1); // no stop 00258 i2c.read(address, data, 1, 0); 00259 return data[0]; 00260 } 00261 00262 void readBytes(uint8_t address, uint8_t subAddress, uint8_t count, uint8_t * dest) 00263 { 00264 char data[14]; 00265 char data_write[1]; 00266 data_write[0] = subAddress; 00267 i2c.write(address, data_write, 1, 1); // no stop 00268 i2c.read(address, data, count, 0); 00269 for(int ii = 0; ii < count; ii++) { 00270 dest[ii] = data[ii]; 00271 } 00272 } 00273 00274 00275 void getMres() { 00276 switch (Mscale) 00277 { 00278 // Possible magnetometer scales (and their register bit settings) are: 00279 // 14 bit resolution (0) and 16 bit resolution (1) 00280 case MFS_14BITS: 00281 mRes = 10.0*4912.0/8190.0; // Proper scale to return milliGauss 00282 break; 00283 case MFS_16BITS: 00284 mRes = 10.0*4912.0/32760.0; // Proper scale to return milliGauss 00285 break; 00286 } 00287 } 00288 00289 00290 void getGres() { 00291 switch (Gscale) 00292 { 00293 // Possible gyro scales (and their register bit settings) are: 00294 // 250 DPS (00), 500 DPS (01), 1000 DPS (10), and 2000 DPS (11). 00295 // Here's a bit of an algorith to calculate DPS/(ADC tick) based on that 2-bit value: 00296 case GFS_250DPS: 00297 gRes = 250.0f/32768.0f; 00298 break; 00299 case GFS_500DPS: 00300 gRes = 500.0f/32768.0f; 00301 break; 00302 case GFS_1000DPS: 00303 gRes = 1000.0f/32768.0f; 00304 break; 00305 case GFS_2000DPS: 00306 gRes = 2000.0f/32768.0f; 00307 break; 00308 } 00309 } 00310 00311 00312 void getAres() { 00313 switch (Ascale) 00314 { 00315 // Possible accelerometer scales (and their register bit settings) are: 00316 // 2 Gs (00), 4 Gs (01), 8 Gs (10), and 16 Gs (11). 00317 // Here's a bit of an algorith to calculate DPS/(ADC tick) based on that 2-bit value: 00318 case AFS_2G: 00319 aRes = 2.0f/32768.0f; 00320 break; 00321 case AFS_4G: 00322 aRes = 4.0f/32768.0f; 00323 break; 00324 case AFS_8G: 00325 aRes = 8.0f/32768.0f; 00326 break; 00327 case AFS_16G: 00328 aRes = 16.0f/32768.0f; 00329 break; 00330 } 00331 } 00332 00333 void readMPU9250Data(int16_t * destination) 00334 { 00335 uint8_t rawData[14]; // x/y/z accel register data stored here 00336 readBytes(MPU9250_ADDRESS, ACCEL_XOUT_H, 14, &rawData[0]); // Read the 14 raw data registers into data array 00337 destination[0] = ((int16_t)rawData[0] << 8) | rawData[1] ; // Turn the MSB and LSB into a signed 16-bit value 00338 destination[1] = ((int16_t)rawData[2] << 8) | rawData[3] ; 00339 destination[2] = ((int16_t)rawData[4] << 8) | rawData[5] ; 00340 destination[3] = ((int16_t)rawData[6] << 8) | rawData[7] ; 00341 destination[4] = ((int16_t)rawData[8] << 8) | rawData[9] ; 00342 destination[5] = ((int16_t)rawData[10] << 8) | rawData[11] ; 00343 destination[6] = ((int16_t)rawData[12] << 8) | rawData[13] ; 00344 } 00345 00346 void readAccelData(int16_t * destination) 00347 { 00348 uint8_t rawData[6]; // x/y/z accel register data stored here 00349 readBytes(MPU9250_ADDRESS, ACCEL_XOUT_H, 6, &rawData[0]); // Read the six raw data registers into data array 00350 destination[0] = (int16_t)(((int16_t)rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value 00351 destination[1] = (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ; 00352 destination[2] = (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ; 00353 } 00354 00355 void readGyroData(int16_t * destination) 00356 { 00357 uint8_t rawData[6]; // x/y/z gyro register data stored here 00358 readBytes(MPU9250_ADDRESS, GYRO_XOUT_H, 6, &rawData[0]); // Read the six raw data registers sequentially into data array 00359 destination[0] = (int16_t)(((int16_t)rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value 00360 destination[1] = (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ; 00361 destination[2] = (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ; 00362 } 00363 00364 void readMagData(int16_t * destination) 00365 { 00366 uint8_t rawData[7]; // x/y/z gyro register data, ST2 register stored here, must read ST2 at end of data acquisition 00367 readBytes(AK8963_ADDRESS, AK8963_XOUT_L, 7, &rawData[0]); // Read the six raw data and ST2 registers sequentially into data array 00368 uint8_t c = rawData[6]; // End data read by reading ST2 register 00369 if(!(c & 0x08)) { // Check if magnetic sensor overflow set, if not then report data 00370 destination[0] = ((int16_t)rawData[1] << 8) | rawData[0] ; // Turn the MSB and LSB into a signed 16-bit value 00371 destination[1] = ((int16_t)rawData[3] << 8) | rawData[2] ; // Data stored as little Endian 00372 destination[2] = ((int16_t)rawData[5] << 8) | rawData[4] ; 00373 } 00374 } 00375 00376 int16_t readTempData() 00377 { 00378 uint8_t rawData[2]; // x/y/z gyro register data stored here 00379 readBytes(MPU9250_ADDRESS, TEMP_OUT_H, 2, &rawData[0]); // Read the two raw data registers sequentially into data array 00380 return (int16_t)(((int16_t)rawData[0]) << 8 | rawData[1]) ; // Turn the MSB and LSB into a 16-bit value 00381 } 00382 00383 00384 void resetMPU9250() { 00385 // reset device 00386 writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x80); // Write a one to bit 7 reset bit; toggle reset device 00387 wait(0.1); 00388 } 00389 00390 void initAK8963(float * destination) 00391 { 00392 // First extract the factory calibration for each magnetometer axis 00393 uint8_t rawData[3] = {0, 0, 0}; // x/y/z gyro calibration data stored here 00394 writeByte(AK8963_ADDRESS, AK8963_CNTL, 0x00); // Power down magnetometer 00395 wait(0.01); 00396 writeByte(AK8963_ADDRESS, AK8963_CNTL, 0x0F); // Enter Fuse ROM access mode 00397 wait(0.01); 00398 // readBytes(AK8963_ADDRESS, AK8963_ASAX, 3, &rawData[0]); // Read the x-, y-, and z-axis calibration values 00399 rawData[0] = readByte(AK8963_ADDRESS, AK8963_ASAX); 00400 rawData[1] = readByte(AK8963_ADDRESS, AK8963_ASAY); 00401 rawData[2] = readByte(AK8963_ADDRESS, AK8963_ASAZ); 00402 destination[0] = (float)(rawData[0] - 128)/256.0f + 1.0f; // Return x-axis sensitivity adjustment values, etc. 00403 destination[1] = (float)(rawData[1] - 128)/256.0f + 1.0f; 00404 destination[2] = (float)(rawData[2] - 128)/256.0f + 1.0f; 00405 writeByte(AK8963_ADDRESS, AK8963_CNTL, 0x00); // Power down magnetometer 00406 wait(0.01); 00407 // Configure the magnetometer for continuous read and highest resolution 00408 // set Mscale bit 4 to 1 (0) to enable 16 (14) bit resolution in CNTL register, 00409 // and enable continuous mode data acquisition Mmode (bits [3:0]), 0010 for 8 Hz and 0110 for 100 Hz sample rates 00410 writeByte(AK8963_ADDRESS, AK8963_CNTL, Mscale << 4 | Mmode); // Set magnetometer data resolution and sample ODR 00411 wait(0.01); 00412 } 00413 00414 00415 void initMPU9250() 00416 { 00417 // Initialize MPU9250 device 00418 // wake up device 00419 writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x00); // Clear sleep mode bit (6), enable all sensors 00420 wait(0.1); // Delay 100 ms for PLL to get established on x-axis gyro; should check for PLL ready interrupt 00421 00422 // get stable time source 00423 writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x01); // Set clock source to be PLL with x-axis gyroscope reference, bits 2:0 = 001 00424 00425 // Configure Gyro and Accelerometer 00426 // Disable FSYNC and set accelerometer and gyro bandwidth to 44 and 42 Hz, respectively; 00427 // DLPF_CFG = bits 2:0 = 010; this sets the sample rate at 1 kHz for both 00428 // Maximum delay is 4.9 ms which is just over a 200 Hz maximum rate 00429 writeByte(MPU9250_ADDRESS, CONFIG, 0x03); 00430 00431 // Set sample rate = gyroscope output rate/(1 + SMPLRT_DIV) 00432 writeByte(MPU9250_ADDRESS, SMPLRT_DIV, 0x04); // Use a 200 Hz rate; the same rate set in CONFIG above 00433 00434 // Set gyroscope full scale range 00435 // Range selects FS_SEL and AFS_SEL are 0 - 3, so 2-bit values are left-shifted into positions 4:3 00436 uint8_t c = readByte(MPU9250_ADDRESS, GYRO_CONFIG); 00437 writeByte(MPU9250_ADDRESS, GYRO_CONFIG, c & ~0xE0); // Clear self-test bits [7:5] 00438 writeByte(MPU9250_ADDRESS, GYRO_CONFIG, c & ~0x18); // Clear AFS bits [4:3] 00439 writeByte(MPU9250_ADDRESS, GYRO_CONFIG, c | Gscale << 3); // Set full scale range for the gyro 00440 00441 // Set accelerometer configuration 00442 c = readByte(MPU9250_ADDRESS, ACCEL_CONFIG); 00443 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, c & ~0xE0); // Clear self-test bits [7:5] 00444 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, c & ~0x18); // Clear AFS bits [4:3] 00445 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, c | Ascale << 3); // Set full scale range for the accelerometer 00446 00447 // Set accelerometer sample rate configuration 00448 // It is possible to get a 4 kHz sample rate from the accelerometer by choosing 1 for 00449 // accel_fchoice_b bit [3]; in this case the bandwidth is 1.13 kHz 00450 c = readByte(MPU9250_ADDRESS, ACCEL_CONFIG2); 00451 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG2, c & ~0x0F); // Clear accel_fchoice_b (bit 3) and A_DLPFG (bits [2:0]) 00452 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG2, c | 0x03); // Set accelerometer rate to 1 kHz and bandwidth to 41 Hz 00453 00454 // The accelerometer, gyro, and thermometer are set to 1 kHz sample rates, 00455 // but all these rates are further reduced by a factor of 5 to 200 Hz because of the SMPLRT_DIV setting 00456 00457 // Configure Interrupts and Bypass Enable 00458 // Set interrupt pin active high, push-pull, and clear on read of INT_STATUS, enable I2C_BYPASS_EN so additional chips 00459 // can join the I2C bus and all can be controlled by the Arduino as master 00460 writeByte(MPU9250_ADDRESS, INT_PIN_CFG, 0x12); // INT is 50 microsecond pulse and any read to clear 00461 writeByte(MPU9250_ADDRESS, INT_ENABLE, 0x01); // Enable data ready (bit 0) interrupt 00462 } 00463 00464 // Function which accumulates gyro and accelerometer data after device initialization. It calculates the average 00465 // of the at-rest readings and then loads the resulting offsets into accelerometer and gyro bias registers. 00466 void calibrateMPU9250(float * dest1, float * dest2) 00467 { 00468 uint8_t data[12]; // data array to hold accelerometer and gyro x, y, z, data 00469 uint16_t ii, packet_count, fifo_count; 00470 int32_t gyro_bias[3] = {0, 0, 0}, accel_bias[3] = {0, 0, 0}; 00471 00472 // reset device, reset all registers, clear gyro and accelerometer bias registers 00473 writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x80); // Write a one to bit 7 reset bit; toggle reset device 00474 wait(0.1); 00475 00476 // get stable time source 00477 // Set clock source to be PLL with x-axis gyroscope reference, bits 2:0 = 001 00478 writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x01); 00479 writeByte(MPU9250_ADDRESS, PWR_MGMT_2, 0x00); 00480 wait(0.2); 00481 00482 // Configure device for bias calculation 00483 writeByte(MPU9250_ADDRESS, INT_ENABLE, 0x00); // Disable all interrupts 00484 writeByte(MPU9250_ADDRESS, FIFO_EN, 0x00); // Disable FIFO 00485 writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x00); // Turn on internal clock source 00486 writeByte(MPU9250_ADDRESS, I2C_MST_CTRL, 0x00); // Disable I2C master 00487 writeByte(MPU9250_ADDRESS, USER_CTRL, 0x00); // Disable FIFO and I2C master modes 00488 writeByte(MPU9250_ADDRESS, USER_CTRL, 0x0C); // Reset FIFO and DMP 00489 wait(0.015); 00490 00491 // Configure MPU9250 gyro and accelerometer for bias calculation 00492 writeByte(MPU9250_ADDRESS, CONFIG, 0x01); // Set low-pass filter to 188 Hz 00493 writeByte(MPU9250_ADDRESS, SMPLRT_DIV, 0x00); // Set sample rate to 1 kHz 00494 writeByte(MPU9250_ADDRESS, GYRO_CONFIG, 0x00); // Set gyro full-scale to 250 degrees per second, maximum sensitivity 00495 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, 0x00); // Set accelerometer full-scale to 2 g, maximum sensitivity 00496 00497 uint16_t gyrosensitivity = 131; // = 131 LSB/degrees/sec 00498 uint16_t accelsensitivity = 16384; // = 16384 LSB/g 00499 00500 // Configure FIFO to capture accelerometer and gyro data for bias calculation 00501 writeByte(MPU9250_ADDRESS, USER_CTRL, 0x40); // Enable FIFO 00502 writeByte(MPU9250_ADDRESS, FIFO_EN, 0x78); // Enable gyro and accelerometer sensors for FIFO (max size 512 bytes in MPU-9250) 00503 wait(0.04); // accumulate 40 samples in 80 milliseconds = 480 bytes 00504 00505 // At end of sample accumulation, turn off FIFO sensor read 00506 writeByte(MPU9250_ADDRESS, FIFO_EN, 0x00); // Disable gyro and accelerometer sensors for FIFO 00507 readBytes(MPU9250_ADDRESS, FIFO_COUNTH, 2, &data[0]); // read FIFO sample count 00508 fifo_count = ((uint16_t)data[0] << 8) | data[1]; 00509 packet_count = fifo_count/12;// How many sets of full gyro and accelerometer data for averaging 00510 00511 for (ii = 0; ii < packet_count; ii++) { 00512 int16_t accel_temp[3] = {0, 0, 0}, gyro_temp[3] = {0, 0, 0}; 00513 readBytes(MPU9250_ADDRESS, FIFO_R_W, 12, &data[0]); // read data for averaging 00514 accel_temp[0] = (int16_t) (((int16_t)data[0] << 8) | data[1] ) ; // Form signed 16-bit integer for each sample in FIFO 00515 accel_temp[1] = (int16_t) (((int16_t)data[2] << 8) | data[3] ) ; 00516 accel_temp[2] = (int16_t) (((int16_t)data[4] << 8) | data[5] ) ; 00517 gyro_temp[0] = (int16_t) (((int16_t)data[6] << 8) | data[7] ) ; 00518 gyro_temp[1] = (int16_t) (((int16_t)data[8] << 8) | data[9] ) ; 00519 gyro_temp[2] = (int16_t) (((int16_t)data[10] << 8) | data[11]) ; 00520 00521 accel_bias[0] += (int32_t) accel_temp[0]; // Sum individual signed 16-bit biases to get accumulated signed 32-bit biases 00522 accel_bias[1] += (int32_t) accel_temp[1]; 00523 accel_bias[2] += (int32_t) accel_temp[2]; 00524 gyro_bias[0] += (int32_t) gyro_temp[0]; 00525 gyro_bias[1] += (int32_t) gyro_temp[1]; 00526 gyro_bias[2] += (int32_t) gyro_temp[2]; 00527 00528 } 00529 accel_bias[0] /= (int32_t) packet_count; // Normalize sums to get average count biases 00530 accel_bias[1] /= (int32_t) packet_count; 00531 accel_bias[2] /= (int32_t) packet_count; 00532 gyro_bias[0] /= (int32_t) packet_count; 00533 gyro_bias[1] /= (int32_t) packet_count; 00534 gyro_bias[2] /= (int32_t) packet_count; 00535 00536 if(accel_bias[2] > 0L) {accel_bias[2] -= (int32_t) accelsensitivity;} // Remove gravity from the z-axis accelerometer bias calculation 00537 else {accel_bias[2] += (int32_t) accelsensitivity;} 00538 00539 // Construct the gyro biases for push to the hardware gyro bias registers, which are reset to zero upon device startup 00540 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 00541 data[1] = (-gyro_bias[0]/4) & 0xFF; // Biases are additive, so change sign on calculated average gyro biases 00542 data[2] = (-gyro_bias[1]/4 >> 8) & 0xFF; 00543 data[3] = (-gyro_bias[1]/4) & 0xFF; 00544 data[4] = (-gyro_bias[2]/4 >> 8) & 0xFF; 00545 data[5] = (-gyro_bias[2]/4) & 0xFF; 00546 00547 /// Push gyro biases to hardware registers 00548 /* writeByte(MPU9250_ADDRESS, XG_OFFSET_H, data[0]); 00549 writeByte(MPU9250_ADDRESS, XG_OFFSET_L, data[1]); 00550 writeByte(MPU9250_ADDRESS, YG_OFFSET_H, data[2]); 00551 writeByte(MPU9250_ADDRESS, YG_OFFSET_L, data[3]); 00552 writeByte(MPU9250_ADDRESS, ZG_OFFSET_H, data[4]); 00553 writeByte(MPU9250_ADDRESS, ZG_OFFSET_L, data[5]); 00554 */ 00555 dest1[0] = (float) gyro_bias[0]/(float) gyrosensitivity; // construct gyro bias in deg/s for later manual subtraction 00556 dest1[1] = (float) gyro_bias[1]/(float) gyrosensitivity; 00557 dest1[2] = (float) gyro_bias[2]/(float) gyrosensitivity; 00558 00559 // Construct the accelerometer biases for push to the hardware accelerometer bias registers. These registers contain 00560 // factory trim values which must be added to the calculated accelerometer biases; on boot up these registers will hold 00561 // non-zero values. In addition, bit 0 of the lower byte must be preserved since it is used for temperature 00562 // compensation calculations. Accelerometer bias registers expect bias input as 2048 LSB per g, so that 00563 // the accelerometer biases calculated above must be divided by 8. 00564 00565 int32_t accel_bias_reg[3] = {0, 0, 0}; // A place to hold the factory accelerometer trim biases 00566 readBytes(MPU9250_ADDRESS, XA_OFFSET_H, 2, &data[0]); // Read factory accelerometer trim values 00567 accel_bias_reg[0] = (int16_t) ((int16_t)data[0] << 8) | data[1]; 00568 readBytes(MPU9250_ADDRESS, YA_OFFSET_H, 2, &data[0]); 00569 accel_bias_reg[1] = (int16_t) ((int16_t)data[0] << 8) | data[1]; 00570 readBytes(MPU9250_ADDRESS, ZA_OFFSET_H, 2, &data[0]); 00571 accel_bias_reg[2] = (int16_t) ((int16_t)data[0] << 8) | data[1]; 00572 00573 uint32_t mask = 1uL; // Define mask for temperature compensation bit 0 of lower byte of accelerometer bias registers 00574 uint8_t mask_bit[3] = {0, 0, 0}; // Define array to hold mask bit for each accelerometer bias axis 00575 00576 for(ii = 0; ii < 3; ii++) { 00577 if(accel_bias_reg[ii] & mask) mask_bit[ii] = 0x01; // If temperature compensation bit is set, record that fact in mask_bit 00578 } 00579 00580 // Construct total accelerometer bias, including calculated average accelerometer bias from above 00581 accel_bias_reg[0] -= (accel_bias[0]/8); // Subtract calculated averaged accelerometer bias scaled to 2048 LSB/g (16 g full scale) 00582 accel_bias_reg[1] -= (accel_bias[1]/8); 00583 accel_bias_reg[2] -= (accel_bias[2]/8); 00584 00585 data[0] = (accel_bias_reg[0] >> 8) & 0xFF; 00586 data[1] = (accel_bias_reg[0]) & 0xFF; 00587 data[1] = data[1] | mask_bit[0]; // preserve temperature compensation bit when writing back to accelerometer bias registers 00588 data[2] = (accel_bias_reg[1] >> 8) & 0xFF; 00589 data[3] = (accel_bias_reg[1]) & 0xFF; 00590 data[3] = data[3] | mask_bit[1]; // preserve temperature compensation bit when writing back to accelerometer bias registers 00591 data[4] = (accel_bias_reg[2] >> 8) & 0xFF; 00592 data[5] = (accel_bias_reg[2]) & 0xFF; 00593 data[5] = data[5] | mask_bit[2]; // preserve temperature compensation bit when writing back to accelerometer bias registers 00594 00595 // Apparently this is not working for the acceleration biases in the MPU-9250 00596 // Are we handling the temperature correction bit properly? 00597 // Push accelerometer biases to hardware registers 00598 /* writeByte(MPU9250_ADDRESS, XA_OFFSET_H, data[0]); 00599 writeByte(MPU9250_ADDRESS, XA_OFFSET_L, data[1]); 00600 writeByte(MPU9250_ADDRESS, YA_OFFSET_H, data[2]); 00601 writeByte(MPU9250_ADDRESS, YA_OFFSET_L, data[3]); 00602 writeByte(MPU9250_ADDRESS, ZA_OFFSET_H, data[4]); 00603 writeByte(MPU9250_ADDRESS, ZA_OFFSET_L, data[5]); 00604 */ 00605 // Output scaled accelerometer biases for manual subtraction in the main program 00606 dest2[0] = (float)accel_bias[0]/(float)accelsensitivity; 00607 dest2[1] = (float)accel_bias[1]/(float)accelsensitivity; 00608 dest2[2] = (float)accel_bias[2]/(float)accelsensitivity; 00609 } 00610 00611 void magcalMPU9250(float * dest1, float * dest2) 00612 { 00613 uint16_t ii = 0, sample_count = 0; 00614 int32_t mag_bias[3] = {0, 0, 0}, mag_scale[3] = {0, 0, 0}; 00615 int16_t mag_max[3] = {-32767, -32767, -32767}, mag_min[3] = {32767, 32767, 32767}, mag_temp[3] = {0, 0, 0}; 00616 00617 // shoot for ~fifteen seconds of mag data 00618 if(Mmode == 0x02) sample_count = 128; // at 8 Hz ODR, new mag data is available every 125 ms 00619 if(Mmode == 0x06) sample_count = 1500; // at 100 Hz ODR, new mag data is available every 10 ms 00620 00621 for(ii = 0; ii < sample_count; ii++) { 00622 readMagData(mag_temp); // Read the mag data 00623 00624 for (int jj = 0; jj < 3; jj++) { 00625 if(mag_temp[jj] > mag_max[jj]) mag_max[jj] = mag_temp[jj]; 00626 if(mag_temp[jj] < mag_min[jj]) mag_min[jj] = mag_temp[jj]; 00627 } 00628 00629 if(Mmode == 0x02) wait(0.135); // at 8 Hz ODR, new mag data is available every 125 ms 00630 if(Mmode == 0x06) wait(0.012); // at 100 Hz ODR, new mag data is available every 10 ms 00631 } 00632 00633 // Get hard iron correction 00634 mag_bias[0] = (mag_max[0] + mag_min[0])/2; // get average x mag bias in counts 00635 mag_bias[1] = (mag_max[1] + mag_min[1])/2; // get average y mag bias in counts 00636 mag_bias[2] = (mag_max[2] + mag_min[2])/2; // get average z mag bias in counts 00637 00638 dest1[0] = (float) mag_bias[0]*mRes*magCalibration[0]; // save mag biases in G for main program 00639 dest1[1] = (float) mag_bias[1]*mRes*magCalibration[1]; 00640 dest1[2] = (float) mag_bias[2]*mRes*magCalibration[2]; 00641 00642 // Get soft iron correction estimate 00643 mag_scale[0] = (mag_max[0] - mag_min[0])/2; // get average x axis max chord length in counts 00644 mag_scale[1] = (mag_max[1] - mag_min[1])/2; // get average y axis max chord length in counts 00645 mag_scale[2] = (mag_max[2] - mag_min[2])/2; // get average z axis max chord length in counts 00646 00647 float avg_rad = mag_scale[0] + mag_scale[1] + mag_scale[2]; 00648 avg_rad /= 3.0; 00649 00650 dest2[0] = avg_rad/((float)mag_scale[0]); 00651 dest2[1] = avg_rad/((float)mag_scale[1]); 00652 dest2[2] = avg_rad/((float)mag_scale[2]); 00653 } 00654 00655 00656 // Accelerometer and gyroscope self test; check calibration wrt factory settings 00657 void MPU9250SelfTest(float * destination) // Should return percent deviation from factory trim values, +/- 14 or less deviation is a pass 00658 { 00659 uint8_t rawData[6] = {0, 0, 0, 0, 0, 0}; 00660 uint8_t selfTest[6]; 00661 int32_t gAvg[3] = {0, 0, 0}, aAvg[3] = {0, 0, 0}, aSTAvg[3] = {0, 0, 0}, gSTAvg[3] = {0, 0, 0}; 00662 float factoryTrim[6]; 00663 uint8_t FS = 0; 00664 00665 writeByte(MPU9250_ADDRESS, SMPLRT_DIV, 0x00); // Set gyro sample rate to 1 kHz 00666 writeByte(MPU9250_ADDRESS, CONFIG, 0x02); // Set gyro sample rate to 1 kHz and DLPF to 92 Hz 00667 writeByte(MPU9250_ADDRESS, GYRO_CONFIG, 1<<FS); // Set full scale range for the gyro to 250 dps 00668 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG2, 0x02); // Set accelerometer rate to 1 kHz and bandwidth to 92 Hz 00669 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, 1<<FS); // Set full scale range for the accelerometer to 2 g 00670 00671 for( int ii = 0; ii < 200; ii++) { // get average current values of gyro and acclerometer 00672 00673 readBytes(MPU9250_ADDRESS, ACCEL_XOUT_H, 6, &rawData[0]); // Read the six raw data registers into data array 00674 aAvg[0] += (int16_t)(((int16_t)rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value 00675 aAvg[1] += (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ; 00676 aAvg[2] += (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ; 00677 00678 readBytes(MPU9250_ADDRESS, GYRO_XOUT_H, 6, &rawData[0]); // Read the six raw data registers sequentially into data array 00679 gAvg[0] += (int16_t)(((int16_t)rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value 00680 gAvg[1] += (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ; 00681 gAvg[2] += (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ; 00682 } 00683 00684 for (int ii =0; ii < 3; ii++) { // Get average of 200 values and store as average current readings 00685 aAvg[ii] /= 200; 00686 gAvg[ii] /= 200; 00687 } 00688 00689 // Configure the accelerometer for self-test 00690 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, 0xE0); // Enable self test on all three axes and set accelerometer range to +/- 2 g 00691 writeByte(MPU9250_ADDRESS, GYRO_CONFIG, 0xE0); // Enable self test on all three axes and set gyro range to +/- 250 degrees/s 00692 wait(0.025); // Delay a while to let the device stabilize 00693 00694 for( int ii = 0; ii < 200; ii++) { // get average self-test values of gyro and acclerometer 00695 00696 readBytes(MPU9250_ADDRESS, ACCEL_XOUT_H, 6, &rawData[0]); // Read the six raw data registers into data array 00697 aSTAvg[0] += (int16_t)(((int16_t)rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value 00698 aSTAvg[1] += (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ; 00699 aSTAvg[2] += (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ; 00700 00701 readBytes(MPU9250_ADDRESS, GYRO_XOUT_H, 6, &rawData[0]); // Read the six raw data registers sequentially into data array 00702 gSTAvg[0] += (int16_t)(((int16_t)rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value 00703 gSTAvg[1] += (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ; 00704 gSTAvg[2] += (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ; 00705 } 00706 00707 for (int ii =0; ii < 3; ii++) { // Get average of 200 values and store as average self-test readings 00708 aSTAvg[ii] /= 200; 00709 gSTAvg[ii] /= 200; 00710 } 00711 00712 // Configure the gyro and accelerometer for normal operation 00713 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, 0x00); 00714 writeByte(MPU9250_ADDRESS, GYRO_CONFIG, 0x00); 00715 wait(0.025); // Delay a while to let the device stabilize 00716 00717 // Retrieve accelerometer and gyro factory Self-Test Code from USR_Reg 00718 selfTest[0] = readByte(MPU9250_ADDRESS, SELF_TEST_X_ACCEL); // X-axis accel self-test results 00719 selfTest[1] = readByte(MPU9250_ADDRESS, SELF_TEST_Y_ACCEL); // Y-axis accel self-test results 00720 selfTest[2] = readByte(MPU9250_ADDRESS, SELF_TEST_Z_ACCEL); // Z-axis accel self-test results 00721 selfTest[3] = readByte(MPU9250_ADDRESS, SELF_TEST_X_GYRO); // X-axis gyro self-test results 00722 selfTest[4] = readByte(MPU9250_ADDRESS, SELF_TEST_Y_GYRO); // Y-axis gyro self-test results 00723 selfTest[5] = readByte(MPU9250_ADDRESS, SELF_TEST_Z_GYRO); // Z-axis gyro self-test results 00724 00725 // Retrieve factory self-test value from self-test code reads 00726 factoryTrim[0] = (float)(2620/1<<FS)*(pow( 1.01 , ((float)selfTest[0] - 1.0) )); // FT[Xa] factory trim calculation 00727 factoryTrim[1] = (float)(2620/1<<FS)*(pow( 1.01 , ((float)selfTest[1] - 1.0) )); // FT[Ya] factory trim calculation 00728 factoryTrim[2] = (float)(2620/1<<FS)*(pow( 1.01 , ((float)selfTest[2] - 1.0) )); // FT[Za] factory trim calculation 00729 factoryTrim[3] = (float)(2620/1<<FS)*(pow( 1.01 , ((float)selfTest[3] - 1.0) )); // FT[Xg] factory trim calculation 00730 factoryTrim[4] = (float)(2620/1<<FS)*(pow( 1.01 , ((float)selfTest[4] - 1.0) )); // FT[Yg] factory trim calculation 00731 factoryTrim[5] = (float)(2620/1<<FS)*(pow( 1.01 , ((float)selfTest[5] - 1.0) )); // FT[Zg] factory trim calculation 00732 00733 // Report results as a ratio of (STR - FT)/FT; the change from Factory Trim of the Self-Test Response 00734 // To get percent, must multiply by 100 00735 for (int i = 0; i < 3; i++) { 00736 destination[i] = 100.0f*((float)(aSTAvg[i] - aAvg[i]))/factoryTrim[i] - 100.0f; // Report percent differences 00737 destination[i+3] = 100.0f*((float)(gSTAvg[i] - gAvg[i]))/factoryTrim[i+3] - 100.0f; // Report percent differences 00738 } 00739 00740 } 00741 00742 00743 00744 // Implementation of Sebastian Madgwick's "...efficient orientation filter for... inertial/magnetic sensor arrays" 00745 // (see http://www.x-io.co.uk/category/open-source/ for examples and more details) 00746 // which fuses acceleration, rotation rate, and magnetic moments to produce a quaternion-based estimate of absolute 00747 // device orientation -- which can be converted to yaw, pitch, and roll. Useful for stabilizing quadcopters, etc. 00748 // The performance of the orientation filter is at least as good as conventional Kalman-based filtering algorithms 00749 // but is much less computationally intensive---it can be performed on a 3.3 V Pro Mini operating at 8 MHz! 00750 void MadgwickQuaternionUpdate(float ax, float ay, float az, float gx, float gy, float gz, float mx, float my, float mz) 00751 { 00752 float q1 = q[0], q2 = q[1], q3 = q[2], q4 = q[3]; // short name local variable for readability 00753 float norm; 00754 float hx, hy, _2bx, _2bz; 00755 float s1, s2, s3, s4; 00756 float qDot1, qDot2, qDot3, qDot4; 00757 00758 // Auxiliary variables to avoid repeated arithmetic 00759 float _2q1mx; 00760 float _2q1my; 00761 float _2q1mz; 00762 float _2q2mx; 00763 float _4bx; 00764 float _4bz; 00765 float _2q1 = 2.0f * q1; 00766 float _2q2 = 2.0f * q2; 00767 float _2q3 = 2.0f * q3; 00768 float _2q4 = 2.0f * q4; 00769 float _2q1q3 = 2.0f * q1 * q3; 00770 float _2q3q4 = 2.0f * q3 * q4; 00771 float q1q1 = q1 * q1; 00772 float q1q2 = q1 * q2; 00773 float q1q3 = q1 * q3; 00774 float q1q4 = q1 * q4; 00775 float q2q2 = q2 * q2; 00776 float q2q3 = q2 * q3; 00777 float q2q4 = q2 * q4; 00778 float q3q3 = q3 * q3; 00779 float q3q4 = q3 * q4; 00780 float q4q4 = q4 * q4; 00781 00782 // Normalise accelerometer measurement 00783 norm = sqrtf(ax * ax + ay * ay + az * az); 00784 if (norm == 0.0f) return; // handle NaN 00785 norm = 1.0f/norm; 00786 ax *= norm; 00787 ay *= norm; 00788 az *= norm; 00789 00790 // Normalise magnetometer measurement 00791 norm = sqrtf(mx * mx + my * my + mz * mz); 00792 if (norm == 0.0f) return; // handle NaN 00793 norm = 1.0f/norm; 00794 mx *= norm; 00795 my *= norm; 00796 mz *= norm; 00797 00798 // Reference direction of Earth's magnetic field 00799 _2q1mx = 2.0f * q1 * mx; 00800 _2q1my = 2.0f * q1 * my; 00801 _2q1mz = 2.0f * q1 * mz; 00802 _2q2mx = 2.0f * q2 * mx; 00803 hx = mx * q1q1 - _2q1my * q4 + _2q1mz * q3 + mx * q2q2 + _2q2 * my * q3 + _2q2 * mz * q4 - mx * q3q3 - mx * q4q4; 00804 hy = _2q1mx * q4 + my * q1q1 - _2q1mz * q2 + _2q2mx * q3 - my * q2q2 + my * q3q3 + _2q3 * mz * q4 - my * q4q4; 00805 _2bx = sqrt(hx * hx + hy * hy); 00806 _2bz = -_2q1mx * q3 + _2q1my * q2 + mz * q1q1 + _2q2mx * q4 - mz * q2q2 + _2q3 * my * q4 - mz * q3q3 + mz * q4q4; 00807 _4bx = 2.0f * _2bx; 00808 _4bz = 2.0f * _2bz; 00809 00810 // Gradient decent algorithm corrective step 00811 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); 00812 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); 00813 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); 00814 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); 00815 norm = sqrtf(s1 * s1 + s2 * s2 + s3 * s3 + s4 * s4); // normalise step magnitude 00816 norm = 1.0f/norm; 00817 s1 *= norm; 00818 s2 *= norm; 00819 s3 *= norm; 00820 s4 *= norm; 00821 00822 // Compute rate of change of quaternion 00823 qDot1 = 0.5f * (-q2 * gx - q3 * gy - q4 * gz) - beta * s1; 00824 qDot2 = 0.5f * (q1 * gx + q3 * gz - q4 * gy) - beta * s2; 00825 qDot3 = 0.5f * (q1 * gy - q2 * gz + q4 * gx) - beta * s3; 00826 qDot4 = 0.5f * (q1 * gz + q2 * gy - q3 * gx) - beta * s4; 00827 00828 // Integrate to yield quaternion 00829 q1 += qDot1 * deltat; 00830 q2 += qDot2 * deltat; 00831 q3 += qDot3 * deltat; 00832 q4 += qDot4 * deltat; 00833 norm = sqrtf(q1 * q1 + q2 * q2 + q3 * q3 + q4 * q4); // normalise quaternion 00834 norm = 1.0f/norm; 00835 q[0] = q1 * norm; 00836 q[1] = q2 * norm; 00837 q[2] = q3 * norm; 00838 q[3] = q4 * norm; 00839 00840 } 00841 00842 00843 00844 // Similar to Madgwick scheme but uses proportional and integral filtering on the error between estimated reference vectors and 00845 // measured ones. 00846 void MahonyQuaternionUpdate(float ax, float ay, float az, float gx, float gy, float gz, float mx, float my, float mz) 00847 { 00848 float q1 = q[0], q2 = q[1], q3 = q[2], q4 = q[3]; // short name local variable for readability 00849 float norm; 00850 float hx, hy, bx, bz; 00851 float vx, vy, vz, wx, wy, wz; 00852 float ex, ey, ez; 00853 float pa, pb, pc; 00854 00855 // Auxiliary variables to avoid repeated arithmetic 00856 float q1q1 = q1 * q1; 00857 float q1q2 = q1 * q2; 00858 float q1q3 = q1 * q3; 00859 float q1q4 = q1 * q4; 00860 float q2q2 = q2 * q2; 00861 float q2q3 = q2 * q3; 00862 float q2q4 = q2 * q4; 00863 float q3q3 = q3 * q3; 00864 float q3q4 = q3 * q4; 00865 float q4q4 = q4 * q4; 00866 00867 // Normalise accelerometer measurement 00868 norm = sqrtf(ax * ax + ay * ay + az * az); 00869 if (norm == 0.0f) return; // handle NaN 00870 norm = 1.0f / norm; // use reciprocal for division 00871 ax *= norm; 00872 ay *= norm; 00873 az *= norm; 00874 00875 // Normalise magnetometer measurement 00876 norm = sqrtf(mx * mx + my * my + mz * mz); 00877 if (norm == 0.0f) return; // handle NaN 00878 norm = 1.0f / norm; // use reciprocal for division 00879 mx *= norm; 00880 my *= norm; 00881 mz *= norm; 00882 00883 // Reference direction of Earth's magnetic field 00884 hx = 2.0f * mx * (0.5f - q3q3 - q4q4) + 2.0f * my * (q2q3 - q1q4) + 2.0f * mz * (q2q4 + q1q3); 00885 hy = 2.0f * mx * (q2q3 + q1q4) + 2.0f * my * (0.5f - q2q2 - q4q4) + 2.0f * mz * (q3q4 - q1q2); 00886 bx = sqrtf((hx * hx) + (hy * hy)); 00887 bz = 2.0f * mx * (q2q4 - q1q3) + 2.0f * my * (q3q4 + q1q2) + 2.0f * mz * (0.5f - q2q2 - q3q3); 00888 00889 // Estimated direction of gravity and magnetic field 00890 vx = 2.0f * (q2q4 - q1q3); 00891 vy = 2.0f * (q1q2 + q3q4); 00892 vz = q1q1 - q2q2 - q3q3 + q4q4; 00893 wx = 2.0f * bx * (0.5f - q3q3 - q4q4) + 2.0f * bz * (q2q4 - q1q3); 00894 wy = 2.0f * bx * (q2q3 - q1q4) + 2.0f * bz * (q1q2 + q3q4); 00895 wz = 2.0f * bx * (q1q3 + q2q4) + 2.0f * bz * (0.5f - q2q2 - q3q3); 00896 00897 // Error is cross product between estimated direction and measured direction of gravity 00898 ex = (ay * vz - az * vy) + (my * wz - mz * wy); 00899 ey = (az * vx - ax * vz) + (mz * wx - mx * wz); 00900 ez = (ax * vy - ay * vx) + (mx * wy - my * wx); 00901 if (Ki > 0.0f) 00902 { 00903 eInt[0] += ex; // accumulate integral error 00904 eInt[1] += ey; 00905 eInt[2] += ez; 00906 } 00907 else 00908 { 00909 eInt[0] = 0.0f; // prevent integral wind up 00910 eInt[1] = 0.0f; 00911 eInt[2] = 0.0f; 00912 } 00913 00914 // Apply feedback terms 00915 gx = gx + Kp * ex + Ki * eInt[0]; 00916 gy = gy + Kp * ey + Ki * eInt[1]; 00917 gz = gz + Kp * ez + Ki * eInt[2]; 00918 00919 // Integrate rate of change of quaternion 00920 pa = q2; 00921 pb = q3; 00922 pc = q4; 00923 q1 = q1 + (-q2 * gx - q3 * gy - q4 * gz) * (0.5f * deltat); 00924 q2 = pa + (q1 * gx + pb * gz - pc * gy) * (0.5f * deltat); 00925 q3 = pb + (q1 * gy - pa * gz + pc * gx) * (0.5f * deltat); 00926 q4 = pc + (q1 * gz + pa * gy - pb * gx) * (0.5f * deltat); 00927 00928 // Normalise quaternion 00929 norm = sqrtf(q1 * q1 + q2 * q2 + q3 * q3 + q4 * q4); 00930 norm = 1.0f / norm; 00931 q[0] = q1 * norm; 00932 q[1] = q2 * norm; 00933 q[2] = q3 * norm; 00934 q[3] = q4 * norm; 00935 00936 } 00937 }; 00938 #endif
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