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mpu9250
MPU9250 test with polling or ISR
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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 #define USE_ISR 0 // poll or data ready interrupt 00008 00009 // 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 00010 // above document; the MPU9250 and MPU9150 are virtually identical but the latter has a different register map 00011 // 00012 //Magnetometer Registers 00013 #define AK8963_ADDRESS 0x0C<<1 00014 #define WHO_AM_I_AK8963 0x00 // should return 0x48 00015 #define INFO 0x01 00016 #define AK8963_ST1 0x02 // data ready status bit 0 00017 #define AK8963_XOUT_L 0x03 // data 00018 #define AK8963_XOUT_H 0x04 00019 #define AK8963_YOUT_L 0x05 00020 #define AK8963_YOUT_H 0x06 00021 #define AK8963_ZOUT_L 0x07 00022 #define AK8963_ZOUT_H 0x08 00023 #define AK8963_ST2 0x09 // Data overflow bit 3 and data read error status bit 2 00024 #define AK8963_CNTL 0x0A // Power down (0000), single-measurement (0001), self-test (1000) and Fuse ROM (1111) modes on bits 3:0 00025 #define AK8963_ASTC 0x0C // Self test control 00026 #define AK8963_I2CDIS 0x0F // I2C disable 00027 #define AK8963_ASAX 0x10 // Fuse ROM x-axis sensitivity adjustment value 00028 #define AK8963_ASAY 0x11 // Fuse ROM y-axis sensitivity adjustment value 00029 #define AK8963_ASAZ 0x12 // Fuse ROM z-axis sensitivity adjustment value 00030 00031 #define SELF_TEST_X_GYRO 0x00 00032 #define SELF_TEST_Y_GYRO 0x01 00033 #define SELF_TEST_Z_GYRO 0x02 00034 00035 /*#define X_FINE_GAIN 0x03 // [7:0] fine gain 00036 #define Y_FINE_GAIN 0x04 00037 #define Z_FINE_GAIN 0x05 00038 #define XA_OFFSET_H 0x06 // User-defined trim values for accelerometer 00039 #define XA_OFFSET_L_TC 0x07 00040 #define YA_OFFSET_H 0x08 00041 #define YA_OFFSET_L_TC 0x09 00042 #define ZA_OFFSET_H 0x0A 00043 #define ZA_OFFSET_L_TC 0x0B */ 00044 00045 #define SELF_TEST_X_ACCEL 0x0D 00046 #define SELF_TEST_Y_ACCEL 0x0E 00047 #define SELF_TEST_Z_ACCEL 0x0F 00048 00049 #define SELF_TEST_A 0x10 00050 00051 #define XG_OFFSET_H 0x13 // User-defined trim values for gyroscope 00052 #define XG_OFFSET_L 0x14 00053 #define YG_OFFSET_H 0x15 00054 #define YG_OFFSET_L 0x16 00055 #define ZG_OFFSET_H 0x17 00056 #define ZG_OFFSET_L 0x18 00057 #define SMPLRT_DIV 0x19 00058 #define CONFIG 0x1A 00059 #define GYRO_CONFIG 0x1B 00060 #define ACCEL_CONFIG 0x1C 00061 #define ACCEL_CONFIG2 0x1D 00062 #define LP_ACCEL_ODR 0x1E 00063 #define WOM_THR 0x1F 00064 00065 #define MOT_DUR 0x20 // Duration counter threshold for motion interrupt generation, 1 kHz rate, LSB = 1 ms 00066 #define ZMOT_THR 0x21 // Zero-motion detection threshold bits [7:0] 00067 #define ZRMOT_DUR 0x22 // Duration counter threshold for zero motion interrupt generation, 16 Hz rate, LSB = 64 ms 00068 00069 #define FIFO_EN 0x23 00070 #define I2C_MST_CTRL 0x24 00071 #define I2C_SLV0_ADDR 0x25 00072 #define I2C_SLV0_REG 0x26 00073 #define I2C_SLV0_CTRL 0x27 00074 #define I2C_SLV1_ADDR 0x28 00075 #define I2C_SLV1_REG 0x29 00076 #define I2C_SLV1_CTRL 0x2A 00077 #define I2C_SLV2_ADDR 0x2B 00078 #define I2C_SLV2_REG 0x2C 00079 #define I2C_SLV2_CTRL 0x2D 00080 #define I2C_SLV3_ADDR 0x2E 00081 #define I2C_SLV3_REG 0x2F 00082 #define I2C_SLV3_CTRL 0x30 00083 #define I2C_SLV4_ADDR 0x31 00084 #define I2C_SLV4_REG 0x32 00085 #define I2C_SLV4_DO 0x33 00086 #define I2C_SLV4_CTRL 0x34 00087 #define I2C_SLV4_DI 0x35 00088 #define I2C_MST_STATUS 0x36 00089 #define INT_PIN_CFG 0x37 00090 #define INT_ENABLE 0x38 00091 #define DMP_INT_STATUS 0x39 // Check DMP interrupt 00092 #define INT_STATUS 0x3A 00093 #define ACCEL_XOUT_H 0x3B 00094 #define ACCEL_XOUT_L 0x3C 00095 #define ACCEL_YOUT_H 0x3D 00096 #define ACCEL_YOUT_L 0x3E 00097 #define ACCEL_ZOUT_H 0x3F 00098 #define ACCEL_ZOUT_L 0x40 00099 #define TEMP_OUT_H 0x41 00100 #define TEMP_OUT_L 0x42 00101 #define GYRO_XOUT_H 0x43 00102 #define GYRO_XOUT_L 0x44 00103 #define GYRO_YOUT_H 0x45 00104 #define GYRO_YOUT_L 0x46 00105 #define GYRO_ZOUT_H 0x47 00106 #define GYRO_ZOUT_L 0x48 00107 #define EXT_SENS_DATA_00 0x49 00108 #define EXT_SENS_DATA_01 0x4A 00109 #define EXT_SENS_DATA_02 0x4B 00110 #define EXT_SENS_DATA_03 0x4C 00111 #define EXT_SENS_DATA_04 0x4D 00112 #define EXT_SENS_DATA_05 0x4E 00113 #define EXT_SENS_DATA_06 0x4F 00114 #define EXT_SENS_DATA_07 0x50 00115 #define EXT_SENS_DATA_08 0x51 00116 #define EXT_SENS_DATA_09 0x52 00117 #define EXT_SENS_DATA_10 0x53 00118 #define EXT_SENS_DATA_11 0x54 00119 #define EXT_SENS_DATA_12 0x55 00120 #define EXT_SENS_DATA_13 0x56 00121 #define EXT_SENS_DATA_14 0x57 00122 #define EXT_SENS_DATA_15 0x58 00123 #define EXT_SENS_DATA_16 0x59 00124 #define EXT_SENS_DATA_17 0x5A 00125 #define EXT_SENS_DATA_18 0x5B 00126 #define EXT_SENS_DATA_19 0x5C 00127 #define EXT_SENS_DATA_20 0x5D 00128 #define EXT_SENS_DATA_21 0x5E 00129 #define EXT_SENS_DATA_22 0x5F 00130 #define EXT_SENS_DATA_23 0x60 00131 #define MOT_DETECT_STATUS 0x61 00132 #define I2C_SLV0_DO 0x63 00133 #define I2C_SLV1_DO 0x64 00134 #define I2C_SLV2_DO 0x65 00135 #define I2C_SLV3_DO 0x66 00136 #define I2C_MST_DELAY_CTRL 0x67 00137 #define SIGNAL_PATH_RESET 0x68 00138 #define MOT_DETECT_CTRL 0x69 00139 #define USER_CTRL 0x6A // Bit 7 enable DMP, bit 3 reset DMP 00140 #define PWR_MGMT_1 0x6B // Device defaults to the SLEEP mode 00141 #define PWR_MGMT_2 0x6C 00142 #define DMP_BANK 0x6D // Activates a specific bank in the DMP 00143 #define DMP_RW_PNT 0x6E // Set read/write pointer to a specific start address in specified DMP bank 00144 #define DMP_REG 0x6F // Register in DMP from which to read or to which to write 00145 #define DMP_REG_1 0x70 00146 #define DMP_REG_2 0x71 00147 #define FIFO_COUNTH 0x72 00148 #define FIFO_COUNTL 0x73 00149 #define FIFO_R_W 0x74 00150 #define WHO_AM_I_MPU9250 0x75 // Should return 0x71 00151 #define XA_OFFSET_H 0x77 00152 #define XA_OFFSET_L 0x78 00153 #define YA_OFFSET_H 0x7A 00154 #define YA_OFFSET_L 0x7B 00155 #define ZA_OFFSET_H 0x7D 00156 #define ZA_OFFSET_L 0x7E 00157 00158 // Using the MSENSR-9250 breakout board, ADO is set to 0 00159 // Seven-bit device address is 110100 for ADO = 0 and 110101 for ADO = 1 00160 //mbed uses the eight-bit device address, so shift seven-bit addresses left by one! 00161 #define ADO 0 00162 #if ADO 00163 #define MPU9250_ADDRESS 0x69<<1 // Device address when ADO = 1 00164 #else 00165 #define MPU9250_ADDRESS 0x68<<1 // Device address when ADO = 0 00166 #endif 00167 00168 // Set initial input parameters 00169 enum Ascale { 00170 AFS_2G = 0, 00171 AFS_4G, 00172 AFS_8G, 00173 AFS_16G 00174 }; 00175 00176 enum Gscale { 00177 GFS_250DPS = 0, 00178 GFS_500DPS, 00179 GFS_1000DPS, 00180 GFS_2000DPS 00181 }; 00182 00183 enum Mscale { 00184 MFS_14BITS = 0, // 0.6 mG per LSB 00185 MFS_16BITS // 0.15 mG per LSB 00186 }; 00187 00188 uint8_t Ascale = AFS_2G; // AFS_2G, AFS_4G, AFS_8G, AFS_16G 00189 uint8_t Gscale = GFS_250DPS; // GFS_250DPS, GFS_500DPS, GFS_1000DPS, GFS_2000DPS 00190 uint8_t Mscale = MFS_16BITS; // MFS_14BITS or MFS_16BITS, 14-bit or 16-bit magnetometer resolution 00191 uint8_t Mmode = 0x06; // Either 8 Hz 0x02) or 100 Hz (0x06) magnetometer data ODR 00192 float aRes, gRes, mRes; // scale resolutions per LSB for the sensors 00193 00194 //Set up I2C, (SDA,SCL) 00195 //#define I2C_SDA PB_7 00196 //#define I2C_SCL PB_6 00197 I2C i2c(I2C_SDA, I2C_SCL); 00198 00199 DigitalOut myled(LED1); 00200 00201 // Pin definitions 00202 int intPin = 12; // These can be changed, 2 and 3 are the Arduinos ext int pins 00203 00204 int16_t accelCount[3]; // Stores the 16-bit signed accelerometer sensor output 00205 int16_t gyroCount[3]; // Stores the 16-bit signed gyro sensor output 00206 int16_t magCount[3]; // Stores the 16-bit signed magnetometer sensor output 00207 float magCalibration[3] = {0, 0, 0}, magbias[3] = {0, 0, 0}; // Factory mag calibration and mag bias 00208 float gyroBias[3] = {0, 0, 0}, accelBias[3] = {0, 0, 0}; // Bias corrections for gyro and accelerometer 00209 float ax, ay, az, gx, gy, gz, mx, my, mz; // variables to hold latest sensor data values 00210 int16_t tempCount; // Stores the real internal chip temperature in degrees Celsius 00211 float temperature; 00212 float SelfTest[6]; 00213 00214 int delt_t = 0; // used to control display output rate 00215 int count = 0; // used to control display output rate 00216 00217 // parameters for 6 DoF sensor fusion calculations 00218 float PI = 3.14159265358979323846f; 00219 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 00220 float beta = sqrtf(3.0f / 4.0f) * GyroMeasError; // compute beta 00221 float GyroMeasDrift = PI * (1.0f / 180.0f); // gyroscope measurement drift in rad/s/s (start at 0.0 deg/s/s) 00222 float zeta = sqrtf(3.0f / 4.0f) * GyroMeasDrift; // compute zeta, the other free parameter in the Madgwick scheme usually set to a small or zero value 00223 #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 00224 #define Ki 0.0f 00225 00226 float pitch, yaw, roll; 00227 float deltat = 0.0f; // integration interval for both filter schemes 00228 int lastUpdate = 0, firstUpdate = 0, Now = 0; // used to calculate integration interval // used to calculate integration interval 00229 float q[4] = {1.0f, 0.0f, 0.0f, 0.0f}; // vector to hold quaternion 00230 float eInt[3] = {0.0f, 0.0f, 0.0f}; // vector to hold integral error for Mahony method 00231 00232 class MPU9250 { 00233 00234 protected: 00235 00236 public: 00237 //=================================================================================================================== 00238 //====== Set of useful function to access acceleratio, gyroscope, and temperature data 00239 //=================================================================================================================== 00240 00241 void writeByte(uint8_t address, uint8_t subAddress, uint8_t data) 00242 { 00243 char data_write[2]; 00244 data_write[0] = subAddress; 00245 data_write[1] = data; 00246 i2c.write(address, data_write, 2, 0); 00247 } 00248 00249 char readByte(uint8_t address, uint8_t subAddress) 00250 { 00251 char data[1]; // `data` will store the register data 00252 char data_write[1]; 00253 data_write[0] = subAddress; 00254 i2c.write(address, data_write, 1, 1); // no stop 00255 i2c.read(address, data, 1, 0); 00256 return data[0]; 00257 } 00258 00259 void readBytes(uint8_t address, uint8_t subAddress, uint8_t count, uint8_t * dest) 00260 { 00261 char data[14]; 00262 char data_write[1]; 00263 data_write[0] = subAddress; 00264 i2c.write(address, data_write, 1, 1); // no stop 00265 i2c.read(address, data, count, 0); 00266 for(int ii = 0; ii < count; ii++) { 00267 dest[ii] = data[ii]; 00268 } 00269 } 00270 00271 00272 void getMres() { 00273 switch (Mscale) 00274 { 00275 // Possible magnetometer scales (and their register bit settings) are: 00276 // 14 bit resolution (0) and 16 bit resolution (1) 00277 case MFS_14BITS: 00278 mRes = 10.0*4219.0/8190.0; // Proper scale to return milliGauss 00279 break; 00280 case MFS_16BITS: 00281 mRes = 10.0*4219.0/32760.0; // Proper scale to return milliGauss 00282 break; 00283 } 00284 } 00285 00286 00287 void getGres() { 00288 switch (Gscale) 00289 { 00290 // Possible gyro scales (and their register bit settings) are: 00291 // 250 DPS (00), 500 DPS (01), 1000 DPS (10), and 2000 DPS (11). 00292 // Here's a bit of an algorith to calculate DPS/(ADC tick) based on that 2-bit value: 00293 case GFS_250DPS: 00294 gRes = 250.0/32768.0; 00295 break; 00296 case GFS_500DPS: 00297 gRes = 500.0/32768.0; 00298 break; 00299 case GFS_1000DPS: 00300 gRes = 1000.0/32768.0; 00301 break; 00302 case GFS_2000DPS: 00303 gRes = 2000.0/32768.0; 00304 break; 00305 } 00306 } 00307 00308 00309 void getAres() { 00310 switch (Ascale) 00311 { 00312 // Possible accelerometer scales (and their register bit settings) are: 00313 // 2 Gs (00), 4 Gs (01), 8 Gs (10), and 16 Gs (11). 00314 // Here's a bit of an algorith to calculate DPS/(ADC tick) based on that 2-bit value: 00315 case AFS_2G: 00316 aRes = 2.0/32768.0; 00317 break; 00318 case AFS_4G: 00319 aRes = 4.0/32768.0; 00320 break; 00321 case AFS_8G: 00322 aRes = 8.0/32768.0; 00323 break; 00324 case AFS_16G: 00325 aRes = 16.0/32768.0; 00326 break; 00327 } 00328 } 00329 00330 00331 void readAccelData(int16_t * destination) 00332 { 00333 uint8_t rawData[6]; // x/y/z accel register data stored here 00334 readBytes(MPU9250_ADDRESS, ACCEL_XOUT_H, 6, &rawData[0]); // Read the six raw data registers into data array 00335 destination[0] = (int16_t)(((int16_t)rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value 00336 destination[1] = (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ; 00337 destination[2] = (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ; 00338 } 00339 00340 void readGyroData(int16_t * destination) 00341 { 00342 uint8_t rawData[6]; // x/y/z gyro register data stored here 00343 readBytes(MPU9250_ADDRESS, GYRO_XOUT_H, 6, &rawData[0]); // Read the six raw data registers sequentially into data array 00344 destination[0] = (int16_t)(((int16_t)rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value 00345 destination[1] = (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ; 00346 destination[2] = (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ; 00347 } 00348 00349 void readMagData(int16_t * destination) 00350 { 00351 uint8_t rawData[7]; // x/y/z gyro register data, ST2 register stored here, must read ST2 at end of data acquisition 00352 if(readByte(AK8963_ADDRESS, AK8963_ST1) & 0x01) { // wait for magnetometer data ready bit to be set 00353 readBytes(AK8963_ADDRESS, AK8963_XOUT_L, 7, &rawData[0]); // Read the six raw data and ST2 registers sequentially into data array 00354 uint8_t c = rawData[6]; // End data read by reading ST2 register 00355 if(!(c & 0x08)) { // Check if magnetic sensor overflow set, if not then report data 00356 destination[0] = (int16_t)(((int16_t)rawData[1] << 8) | rawData[0]); // Turn the MSB and LSB into a signed 16-bit value 00357 destination[1] = (int16_t)(((int16_t)rawData[3] << 8) | rawData[2]) ; // Data stored as little Endian 00358 destination[2] = (int16_t)(((int16_t)rawData[5] << 8) | rawData[4]) ; 00359 } 00360 } 00361 } 00362 00363 int16_t readTempData() 00364 { 00365 uint8_t rawData[2]; // x/y/z gyro register data stored here 00366 readBytes(MPU9250_ADDRESS, TEMP_OUT_H, 2, &rawData[0]); // Read the two raw data registers sequentially into data array 00367 return (int16_t)(((int16_t)rawData[0]) << 8 | rawData[1]) ; // Turn the MSB and LSB into a 16-bit value 00368 } 00369 00370 00371 void resetMPU9250() { 00372 // reset device 00373 writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x80); // Write a one to bit 7 reset bit; toggle reset device 00374 wait(0.1); 00375 } 00376 00377 void initAK8963(float * destination) 00378 { 00379 // First extract the factory calibration for each magnetometer axis 00380 uint8_t rawData[3]; // x/y/z gyro calibration data stored here 00381 writeByte(AK8963_ADDRESS, AK8963_CNTL, 0x00); // Power down magnetometer 00382 wait(0.01); 00383 writeByte(AK8963_ADDRESS, AK8963_CNTL, 0x0F); // Enter Fuse ROM access mode 00384 wait(0.01); 00385 readBytes(AK8963_ADDRESS, AK8963_ASAX, 3, &rawData[0]); // Read the x-, y-, and z-axis calibration values 00386 destination[0] = (float)(rawData[0] - 128)/256.0f + 1.0f; // Return x-axis sensitivity adjustment values, etc. 00387 destination[1] = (float)(rawData[1] - 128)/256.0f + 1.0f; 00388 destination[2] = (float)(rawData[2] - 128)/256.0f + 1.0f; 00389 writeByte(AK8963_ADDRESS, AK8963_CNTL, 0x00); // Power down magnetometer 00390 wait(0.01); 00391 // Configure the magnetometer for continuous read and highest resolution 00392 // set Mscale bit 4 to 1 (0) to enable 16 (14) bit resolution in CNTL register, 00393 // and enable continuous mode data acquisition Mmode (bits [3:0]), 0010 for 8 Hz and 0110 for 100 Hz sample rates 00394 writeByte(AK8963_ADDRESS, AK8963_CNTL, Mscale << 4 | Mmode); // Set magnetometer data resolution and sample ODR 00395 wait(0.01); 00396 } 00397 00398 00399 void initMPU9250() 00400 { 00401 // Initialize MPU9250 device 00402 // wake up device 00403 writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x00); // Clear sleep mode bit (6), enable all sensors 00404 wait(0.1); // Delay 100 ms for PLL to get established on x-axis gyro; should check for PLL ready interrupt 00405 00406 // get stable time source 00407 writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x01); // Set clock source to be PLL with x-axis gyroscope reference, bits 2:0 = 001 00408 00409 // Configure Gyro and Accelerometer 00410 // Disable FSYNC and set accelerometer and gyro bandwidth to 44 and 42 Hz, respectively; 00411 // DLPF_CFG = bits 2:0 = 010; this sets the sample rate at 1 kHz for both 00412 // Maximum delay is 4.9 ms which is just over a 200 Hz maximum rate 00413 writeByte(MPU9250_ADDRESS, CONFIG, 0x03); 00414 00415 // Set sample rate = gyroscope output rate/(1 + SMPLRT_DIV) 00416 writeByte(MPU9250_ADDRESS, SMPLRT_DIV, 0x04); // Use a 200 Hz rate; the same rate set in CONFIG above 00417 00418 // Set gyroscope full scale range 00419 // Range selects FS_SEL and AFS_SEL are 0 - 3, so 2-bit values are left-shifted into positions 4:3 00420 uint8_t c = readByte(MPU9250_ADDRESS, GYRO_CONFIG); // get current GYRO_CONFIG register value 00421 // c = c & ~0xE0; // Clear self-test bits [7:5] 00422 c = c & ~0x02; // Clear Fchoice bits [1:0] 00423 c = c & ~0x18; // Clear AFS bits [4:3] 00424 c = c | Gscale << 3; // Set full scale range for the gyro 00425 // c =| 0x00; // Set Fchoice for the gyro to 11 by writing its inverse to bits 1:0 of GYRO_CONFIG 00426 writeByte(MPU9250_ADDRESS, GYRO_CONFIG, c ); // Write new GYRO_CONFIG value to register 00427 00428 // Set accelerometer full-scale range configuration 00429 c = readByte(MPU9250_ADDRESS, ACCEL_CONFIG); // get current ACCEL_CONFIG register value 00430 // c = c & ~0xE0; // Clear self-test bits [7:5] 00431 c = c & ~0x18; // Clear AFS bits [4:3] 00432 c = c | Ascale << 3; // Set full scale range for the accelerometer 00433 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, c); // Write new ACCEL_CONFIG register value 00434 00435 // Set accelerometer sample rate configuration 00436 // It is possible to get a 4 kHz sample rate from the accelerometer by choosing 1 for 00437 // accel_fchoice_b bit [3]; in this case the bandwidth is 1.13 kHz 00438 c = readByte(MPU9250_ADDRESS, ACCEL_CONFIG2); // get current ACCEL_CONFIG2 register value 00439 c = c & ~0x0F; // Clear accel_fchoice_b (bit 3) and A_DLPFG (bits [2:0]) 00440 c = c | 0x03; // Set accelerometer rate to 1 kHz and bandwidth to 41 Hz 00441 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG2, c); // Write new ACCEL_CONFIG2 register value 00442 00443 // The accelerometer, gyro, and thermometer are set to 1 kHz sample rates, 00444 // but all these rates are further reduced by a factor of 5 to 200 Hz because of the SMPLRT_DIV setting 00445 00446 // Configure Interrupts and Bypass Enable 00447 // Set interrupt pin active high, push-pull, and clear on read of INT_STATUS, enable I2C_BYPASS_EN so additional chips 00448 // can join the I2C bus and all can be controlled by the Arduino as master 00449 00450 #if USE_ISR 00451 writeByte(MPU9250_ADDRESS, INT_PIN_CFG, 0x12); // INT is 50 microsecond pulse and any read to clear 00452 #else 00453 writeByte(MPU9250_ADDRESS, INT_PIN_CFG, 0x22); 00454 #endif 00455 writeByte(MPU9250_ADDRESS, INT_ENABLE, 0x01); // Enable data ready (bit 0) interrupt 00456 } 00457 00458 // Function which accumulates gyro and accelerometer data after device initialization. It calculates the average 00459 // of the at-rest readings and then loads the resulting offsets into accelerometer and gyro bias registers. 00460 void calibrateMPU9250(float * dest1, float * dest2) 00461 { 00462 uint8_t data[12]; // data array to hold accelerometer and gyro x, y, z, data 00463 uint16_t ii, packet_count, fifo_count; 00464 int32_t gyro_bias[3] = {0, 0, 0}, accel_bias[3] = {0, 0, 0}; 00465 00466 // reset device, reset all registers, clear gyro and accelerometer bias registers 00467 writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x80); // Write a one to bit 7 reset bit; toggle reset device 00468 wait(0.1); 00469 00470 // get stable time source 00471 // Set clock source to be PLL with x-axis gyroscope reference, bits 2:0 = 001 00472 writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x01); 00473 writeByte(MPU9250_ADDRESS, PWR_MGMT_2, 0x00); 00474 wait(0.2); 00475 00476 // Configure device for bias calculation 00477 writeByte(MPU9250_ADDRESS, INT_ENABLE, 0x00); // Disable all interrupts 00478 writeByte(MPU9250_ADDRESS, FIFO_EN, 0x00); // Disable FIFO 00479 writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x00); // Turn on internal clock source 00480 writeByte(MPU9250_ADDRESS, I2C_MST_CTRL, 0x00); // Disable I2C master 00481 writeByte(MPU9250_ADDRESS, USER_CTRL, 0x00); // Disable FIFO and I2C master modes 00482 writeByte(MPU9250_ADDRESS, USER_CTRL, 0x0C); // Reset FIFO and DMP 00483 wait(0.015); 00484 00485 // Configure MPU9250 gyro and accelerometer for bias calculation 00486 writeByte(MPU9250_ADDRESS, CONFIG, 0x01); // Set low-pass filter to 188 Hz 00487 writeByte(MPU9250_ADDRESS, SMPLRT_DIV, 0x00); // Set sample rate to 1 kHz 00488 writeByte(MPU9250_ADDRESS, GYRO_CONFIG, 0x00); // Set gyro full-scale to 250 degrees per second, maximum sensitivity 00489 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, 0x00); // Set accelerometer full-scale to 2 g, maximum sensitivity 00490 00491 uint16_t gyrosensitivity = 131; // = 131 LSB/degrees/sec 00492 uint16_t accelsensitivity = 16384; // = 16384 LSB/g 00493 00494 // Configure FIFO to capture accelerometer and gyro data for bias calculation 00495 writeByte(MPU9250_ADDRESS, USER_CTRL, 0x40); // Enable FIFO 00496 writeByte(MPU9250_ADDRESS, FIFO_EN, 0x78); // Enable gyro and accelerometer sensors for FIFO (max size 512 bytes in MPU-9250) 00497 wait(0.04); // accumulate 40 samples in 80 milliseconds = 480 bytes 00498 00499 // At end of sample accumulation, turn off FIFO sensor read 00500 writeByte(MPU9250_ADDRESS, FIFO_EN, 0x00); // Disable gyro and accelerometer sensors for FIFO 00501 readBytes(MPU9250_ADDRESS, FIFO_COUNTH, 2, &data[0]); // read FIFO sample count 00502 fifo_count = ((uint16_t)data[0] << 8) | data[1]; 00503 packet_count = fifo_count/12;// How many sets of full gyro and accelerometer data for averaging 00504 00505 for (ii = 0; ii < packet_count; ii++) { 00506 int16_t accel_temp[3] = {0, 0, 0}, gyro_temp[3] = {0, 0, 0}; 00507 readBytes(MPU9250_ADDRESS, FIFO_R_W, 12, &data[0]); // read data for averaging 00508 accel_temp[0] = (int16_t) (((int16_t)data[0] << 8) | data[1] ) ; // Form signed 16-bit integer for each sample in FIFO 00509 accel_temp[1] = (int16_t) (((int16_t)data[2] << 8) | data[3] ) ; 00510 accel_temp[2] = (int16_t) (((int16_t)data[4] << 8) | data[5] ) ; 00511 gyro_temp[0] = (int16_t) (((int16_t)data[6] << 8) | data[7] ) ; 00512 gyro_temp[1] = (int16_t) (((int16_t)data[8] << 8) | data[9] ) ; 00513 gyro_temp[2] = (int16_t) (((int16_t)data[10] << 8) | data[11]) ; 00514 00515 accel_bias[0] += (int32_t) accel_temp[0]; // Sum individual signed 16-bit biases to get accumulated signed 32-bit biases 00516 accel_bias[1] += (int32_t) accel_temp[1]; 00517 accel_bias[2] += (int32_t) accel_temp[2]; 00518 gyro_bias[0] += (int32_t) gyro_temp[0]; 00519 gyro_bias[1] += (int32_t) gyro_temp[1]; 00520 gyro_bias[2] += (int32_t) gyro_temp[2]; 00521 00522 } 00523 accel_bias[0] /= (int32_t) packet_count; // Normalize sums to get average count biases 00524 accel_bias[1] /= (int32_t) packet_count; 00525 accel_bias[2] /= (int32_t) packet_count; 00526 gyro_bias[0] /= (int32_t) packet_count; 00527 gyro_bias[1] /= (int32_t) packet_count; 00528 gyro_bias[2] /= (int32_t) packet_count; 00529 00530 if(accel_bias[2] > 0L) {accel_bias[2] -= (int32_t) accelsensitivity;} // Remove gravity from the z-axis accelerometer bias calculation 00531 else {accel_bias[2] += (int32_t) accelsensitivity;} 00532 00533 // Construct the gyro biases for push to the hardware gyro bias registers, which are reset to zero upon device startup 00534 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 00535 data[1] = (-gyro_bias[0]/4) & 0xFF; // Biases are additive, so change sign on calculated average gyro biases 00536 data[2] = (-gyro_bias[1]/4 >> 8) & 0xFF; 00537 data[3] = (-gyro_bias[1]/4) & 0xFF; 00538 data[4] = (-gyro_bias[2]/4 >> 8) & 0xFF; 00539 data[5] = (-gyro_bias[2]/4) & 0xFF; 00540 00541 /// Push gyro biases to hardware registers 00542 /* writeByte(MPU9250_ADDRESS, XG_OFFSET_H, data[0]); 00543 writeByte(MPU9250_ADDRESS, XG_OFFSET_L, data[1]); 00544 writeByte(MPU9250_ADDRESS, YG_OFFSET_H, data[2]); 00545 writeByte(MPU9250_ADDRESS, YG_OFFSET_L, data[3]); 00546 writeByte(MPU9250_ADDRESS, ZG_OFFSET_H, data[4]); 00547 writeByte(MPU9250_ADDRESS, ZG_OFFSET_L, data[5]); 00548 */ 00549 dest1[0] = (float) gyro_bias[0]/(float) gyrosensitivity; // construct gyro bias in deg/s for later manual subtraction 00550 dest1[1] = (float) gyro_bias[1]/(float) gyrosensitivity; 00551 dest1[2] = (float) gyro_bias[2]/(float) gyrosensitivity; 00552 00553 // Construct the accelerometer biases for push to the hardware accelerometer bias registers. These registers contain 00554 // factory trim values which must be added to the calculated accelerometer biases; on boot up these registers will hold 00555 // non-zero values. In addition, bit 0 of the lower byte must be preserved since it is used for temperature 00556 // compensation calculations. Accelerometer bias registers expect bias input as 2048 LSB per g, so that 00557 // the accelerometer biases calculated above must be divided by 8. 00558 00559 int32_t accel_bias_reg[3] = {0, 0, 0}; // A place to hold the factory accelerometer trim biases 00560 readBytes(MPU9250_ADDRESS, XA_OFFSET_H, 2, &data[0]); // Read factory accelerometer trim values 00561 accel_bias_reg[0] = (int16_t) ((int16_t)data[0] << 8) | data[1]; 00562 readBytes(MPU9250_ADDRESS, YA_OFFSET_H, 2, &data[0]); 00563 accel_bias_reg[1] = (int16_t) ((int16_t)data[0] << 8) | data[1]; 00564 readBytes(MPU9250_ADDRESS, ZA_OFFSET_H, 2, &data[0]); 00565 accel_bias_reg[2] = (int16_t) ((int16_t)data[0] << 8) | data[1]; 00566 00567 uint32_t mask = 1uL; // Define mask for temperature compensation bit 0 of lower byte of accelerometer bias registers 00568 uint8_t mask_bit[3] = {0, 0, 0}; // Define array to hold mask bit for each accelerometer bias axis 00569 00570 for(ii = 0; ii < 3; ii++) { 00571 if(accel_bias_reg[ii] & mask) mask_bit[ii] = 0x01; // If temperature compensation bit is set, record that fact in mask_bit 00572 } 00573 00574 // Construct total accelerometer bias, including calculated average accelerometer bias from above 00575 accel_bias_reg[0] -= (accel_bias[0]/8); // Subtract calculated averaged accelerometer bias scaled to 2048 LSB/g (16 g full scale) 00576 accel_bias_reg[1] -= (accel_bias[1]/8); 00577 accel_bias_reg[2] -= (accel_bias[2]/8); 00578 00579 data[0] = (accel_bias_reg[0] >> 8) & 0xFF; 00580 data[1] = (accel_bias_reg[0]) & 0xFF; 00581 data[1] = data[1] | mask_bit[0]; // preserve temperature compensation bit when writing back to accelerometer bias registers 00582 data[2] = (accel_bias_reg[1] >> 8) & 0xFF; 00583 data[3] = (accel_bias_reg[1]) & 0xFF; 00584 data[3] = data[3] | mask_bit[1]; // preserve temperature compensation bit when writing back to accelerometer bias registers 00585 data[4] = (accel_bias_reg[2] >> 8) & 0xFF; 00586 data[5] = (accel_bias_reg[2]) & 0xFF; 00587 data[5] = data[5] | mask_bit[2]; // preserve temperature compensation bit when writing back to accelerometer bias registers 00588 00589 // Apparently this is not working for the acceleration biases in the MPU-9250 00590 // Are we handling the temperature correction bit properly? 00591 // Push accelerometer biases to hardware registers 00592 /* writeByte(MPU9250_ADDRESS, XA_OFFSET_H, data[0]); 00593 writeByte(MPU9250_ADDRESS, XA_OFFSET_L, data[1]); 00594 writeByte(MPU9250_ADDRESS, YA_OFFSET_H, data[2]); 00595 writeByte(MPU9250_ADDRESS, YA_OFFSET_L, data[3]); 00596 writeByte(MPU9250_ADDRESS, ZA_OFFSET_H, data[4]); 00597 writeByte(MPU9250_ADDRESS, ZA_OFFSET_L, data[5]); 00598 */ 00599 // Output scaled accelerometer biases for manual subtraction in the main program 00600 dest2[0] = (float)accel_bias[0]/(float)accelsensitivity; 00601 dest2[1] = (float)accel_bias[1]/(float)accelsensitivity; 00602 dest2[2] = (float)accel_bias[2]/(float)accelsensitivity; 00603 } 00604 00605 00606 // Accelerometer and gyroscope self test; check calibration wrt factory settings 00607 void MPU9250SelfTest(float * destination) // Should return percent deviation from factory trim values, +/- 14 or less deviation is a pass 00608 { 00609 uint8_t rawData[6] = {0, 0, 0, 0, 0, 0}; 00610 uint8_t selfTest[6]; 00611 int32_t gAvg[3] = {0}, aAvg[3] = {0}, aSTAvg[3] = {0}, gSTAvg[3] = {0}; 00612 float factoryTrim[6]; 00613 uint8_t FS = 0; 00614 00615 writeByte(MPU9250_ADDRESS, SMPLRT_DIV, 0x00); // Set gyro sample rate to 1 kHz 00616 writeByte(MPU9250_ADDRESS, CONFIG, 0x02); // Set gyro sample rate to 1 kHz and DLPF to 92 Hz 00617 writeByte(MPU9250_ADDRESS, GYRO_CONFIG, 1<<FS); // Set full scale range for the gyro to 250 dps 00618 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG2, 0x02); // Set accelerometer rate to 1 kHz and bandwidth to 92 Hz 00619 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, 1<<FS); // Set full scale range for the accelerometer to 2 g 00620 00621 for( int ii = 0; ii < 200; ii++) { // get average current values of gyro and acclerometer 00622 00623 readBytes(MPU9250_ADDRESS, ACCEL_XOUT_H, 6, &rawData[0]); // Read the six raw data registers into data array 00624 aAvg[0] += (int16_t)(((int16_t)rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value 00625 aAvg[1] += (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ; 00626 aAvg[2] += (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ; 00627 00628 readBytes(MPU9250_ADDRESS, GYRO_XOUT_H, 6, &rawData[0]); // Read the six raw data registers sequentially into data array 00629 gAvg[0] += (int16_t)(((int16_t)rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value 00630 gAvg[1] += (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ; 00631 gAvg[2] += (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ; 00632 } 00633 00634 for (int ii =0; ii < 3; ii++) { // Get average of 200 values and store as average current readings 00635 aAvg[ii] /= 200; 00636 gAvg[ii] /= 200; 00637 } 00638 00639 // Configure the accelerometer for self-test 00640 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, 0xE0); // Enable self test on all three axes and set accelerometer range to +/- 2 g 00641 writeByte(MPU9250_ADDRESS, GYRO_CONFIG, 0xE0); // Enable self test on all three axes and set gyro range to +/- 250 degrees/s 00642 wait(0.025); // Delay a while to let the device stabilize 00643 00644 for( int ii = 0; ii < 200; ii++) { // get average self-test values of gyro and acclerometer 00645 00646 readBytes(MPU9250_ADDRESS, ACCEL_XOUT_H, 6, &rawData[0]); // Read the six raw data registers into data array 00647 aSTAvg[0] += (int16_t)(((int16_t)rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value 00648 aSTAvg[1] += (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ; 00649 aSTAvg[2] += (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ; 00650 00651 readBytes(MPU9250_ADDRESS, GYRO_XOUT_H, 6, &rawData[0]); // Read the six raw data registers sequentially into data array 00652 gSTAvg[0] += (int16_t)(((int16_t)rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value 00653 gSTAvg[1] += (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ; 00654 gSTAvg[2] += (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ; 00655 } 00656 00657 for (int ii =0; ii < 3; ii++) { // Get average of 200 values and store as average self-test readings 00658 aSTAvg[ii] /= 200; 00659 gSTAvg[ii] /= 200; 00660 } 00661 00662 // Configure the gyro and accelerometer for normal operation 00663 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, 0x00); 00664 writeByte(MPU9250_ADDRESS, GYRO_CONFIG, 0x00); 00665 wait(0.025); // Delay a while to let the device stabilize 00666 00667 // Retrieve accelerometer and gyro factory Self-Test Code from USR_Reg 00668 selfTest[0] = readByte(MPU9250_ADDRESS, SELF_TEST_X_ACCEL); // X-axis accel self-test results 00669 selfTest[1] = readByte(MPU9250_ADDRESS, SELF_TEST_Y_ACCEL); // Y-axis accel self-test results 00670 selfTest[2] = readByte(MPU9250_ADDRESS, SELF_TEST_Z_ACCEL); // Z-axis accel self-test results 00671 selfTest[3] = readByte(MPU9250_ADDRESS, SELF_TEST_X_GYRO); // X-axis gyro self-test results 00672 selfTest[4] = readByte(MPU9250_ADDRESS, SELF_TEST_Y_GYRO); // Y-axis gyro self-test results 00673 selfTest[5] = readByte(MPU9250_ADDRESS, SELF_TEST_Z_GYRO); // Z-axis gyro self-test results 00674 00675 // Retrieve factory self-test value from self-test code reads 00676 factoryTrim[0] = (float)(2620/1<<FS)*(pow( 1.01 , ((float)selfTest[0] - 1.0) )); // FT[Xa] factory trim calculation 00677 factoryTrim[1] = (float)(2620/1<<FS)*(pow( 1.01 , ((float)selfTest[1] - 1.0) )); // FT[Ya] factory trim calculation 00678 factoryTrim[2] = (float)(2620/1<<FS)*(pow( 1.01 , ((float)selfTest[2] - 1.0) )); // FT[Za] factory trim calculation 00679 factoryTrim[3] = (float)(2620/1<<FS)*(pow( 1.01 , ((float)selfTest[3] - 1.0) )); // FT[Xg] factory trim calculation 00680 factoryTrim[4] = (float)(2620/1<<FS)*(pow( 1.01 , ((float)selfTest[4] - 1.0) )); // FT[Yg] factory trim calculation 00681 factoryTrim[5] = (float)(2620/1<<FS)*(pow( 1.01 , ((float)selfTest[5] - 1.0) )); // FT[Zg] factory trim calculation 00682 00683 // Report results as a ratio of (STR - FT)/FT; the change from Factory Trim of the Self-Test Response 00684 // To get percent, must multiply by 100 00685 for (int i = 0; i < 3; i++) { 00686 destination[i] = 100.0*((float)(aSTAvg[i] - aAvg[i]))/factoryTrim[i] - 100.; // Report percent differences 00687 destination[i+3] = 100.0*((float)(gSTAvg[i] - gAvg[i]))/factoryTrim[i+3] - 100.; // Report percent differences 00688 } 00689 00690 } 00691 00692 00693 00694 // Implementation of Sebastian Madgwick's "...efficient orientation filter for... inertial/magnetic sensor arrays" 00695 // (see http://www.x-io.co.uk/category/open-source/ for examples and more details) 00696 // which fuses acceleration, rotation rate, and magnetic moments to produce a quaternion-based estimate of absolute 00697 // device orientation -- which can be converted to yaw, pitch, and roll. Useful for stabilizing quadcopters, etc. 00698 // The performance of the orientation filter is at least as good as conventional Kalman-based filtering algorithms 00699 // but is much less computationally intensive---it can be performed on a 3.3 V Pro Mini operating at 8 MHz! 00700 void MadgwickQuaternionUpdate(float ax, float ay, float az, float gx, float gy, float gz, float mx, float my, float mz) 00701 { 00702 float q1 = q[0], q2 = q[1], q3 = q[2], q4 = q[3]; // short name local variable for readability 00703 float norm; 00704 float hx, hy, _2bx, _2bz; 00705 float s1, s2, s3, s4; 00706 float qDot1, qDot2, qDot3, qDot4; 00707 00708 // Auxiliary variables to avoid repeated arithmetic 00709 float _2q1mx; 00710 float _2q1my; 00711 float _2q1mz; 00712 float _2q2mx; 00713 float _4bx; 00714 float _4bz; 00715 float _2q1 = 2.0f * q1; 00716 float _2q2 = 2.0f * q2; 00717 float _2q3 = 2.0f * q3; 00718 float _2q4 = 2.0f * q4; 00719 float _2q1q3 = 2.0f * q1 * q3; 00720 float _2q3q4 = 2.0f * q3 * q4; 00721 float q1q1 = q1 * q1; 00722 float q1q2 = q1 * q2; 00723 float q1q3 = q1 * q3; 00724 float q1q4 = q1 * q4; 00725 float q2q2 = q2 * q2; 00726 float q2q3 = q2 * q3; 00727 float q2q4 = q2 * q4; 00728 float q3q3 = q3 * q3; 00729 float q3q4 = q3 * q4; 00730 float q4q4 = q4 * q4; 00731 00732 // Normalise accelerometer measurement 00733 norm = sqrtf(ax * ax + ay * ay + az * az); 00734 if (norm == 0.0f) return; // handle NaN 00735 norm = 1.0f/norm; 00736 ax *= norm; 00737 ay *= norm; 00738 az *= norm; 00739 00740 // Normalise magnetometer measurement 00741 norm = sqrtf(mx * mx + my * my + mz * mz); 00742 if (norm == 0.0f) return; // handle NaN 00743 norm = 1.0f/norm; 00744 mx *= norm; 00745 my *= norm; 00746 mz *= norm; 00747 00748 // Reference direction of Earth's magnetic field 00749 _2q1mx = 2.0f * q1 * mx; 00750 _2q1my = 2.0f * q1 * my; 00751 _2q1mz = 2.0f * q1 * mz; 00752 _2q2mx = 2.0f * q2 * mx; 00753 hx = mx * q1q1 - _2q1my * q4 + _2q1mz * q3 + mx * q2q2 + _2q2 * my * q3 + _2q2 * mz * q4 - mx * q3q3 - mx * q4q4; 00754 hy = _2q1mx * q4 + my * q1q1 - _2q1mz * q2 + _2q2mx * q3 - my * q2q2 + my * q3q3 + _2q3 * mz * q4 - my * q4q4; 00755 _2bx = sqrtf(hx * hx + hy * hy); 00756 _2bz = -_2q1mx * q3 + _2q1my * q2 + mz * q1q1 + _2q2mx * q4 - mz * q2q2 + _2q3 * my * q4 - mz * q3q3 + mz * q4q4; 00757 _4bx = 2.0f * _2bx; 00758 _4bz = 2.0f * _2bz; 00759 00760 // Gradient decent algorithm corrective step 00761 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); 00762 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); 00763 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); 00764 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); 00765 norm = sqrtf(s1 * s1 + s2 * s2 + s3 * s3 + s4 * s4); // normalise step magnitude 00766 norm = 1.0f/norm; 00767 s1 *= norm; 00768 s2 *= norm; 00769 s3 *= norm; 00770 s4 *= norm; 00771 00772 // Compute rate of change of quaternion 00773 qDot1 = 0.5f * (-q2 * gx - q3 * gy - q4 * gz) - beta * s1; 00774 qDot2 = 0.5f * (q1 * gx + q3 * gz - q4 * gy) - beta * s2; 00775 qDot3 = 0.5f * (q1 * gy - q2 * gz + q4 * gx) - beta * s3; 00776 qDot4 = 0.5f * (q1 * gz + q2 * gy - q3 * gx) - beta * s4; 00777 00778 // Integrate to yield quaternion 00779 q1 += qDot1 * deltat; 00780 q2 += qDot2 * deltat; 00781 q3 += qDot3 * deltat; 00782 q4 += qDot4 * deltat; 00783 norm = sqrt(q1 * q1 + q2 * q2 + q3 * q3 + q4 * q4); // normalise quaternion 00784 norm = 1.0f/norm; 00785 q[0] = q1 * norm; 00786 q[1] = q2 * norm; 00787 q[2] = q3 * norm; 00788 q[3] = q4 * norm; 00789 00790 } 00791 00792 00793 00794 // Similar to Madgwick scheme but uses proportional and integral filtering on the error between estimated reference vectors and 00795 // measured ones. 00796 void MahonyQuaternionUpdate(float ax, float ay, float az, float gx, float gy, float gz, float mx, float my, float mz) 00797 { 00798 float q1 = q[0], q2 = q[1], q3 = q[2], q4 = q[3]; // short name local variable for readability 00799 float norm; 00800 float hx, hy, bx, bz; 00801 float vx, vy, vz, wx, wy, wz; 00802 float ex, ey, ez; 00803 float pa, pb, pc; 00804 00805 // Auxiliary variables to avoid repeated arithmetic 00806 float q1q1 = q1 * q1; 00807 float q1q2 = q1 * q2; 00808 float q1q3 = q1 * q3; 00809 float q1q4 = q1 * q4; 00810 float q2q2 = q2 * q2; 00811 float q2q3 = q2 * q3; 00812 float q2q4 = q2 * q4; 00813 float q3q3 = q3 * q3; 00814 float q3q4 = q3 * q4; 00815 float q4q4 = q4 * q4; 00816 00817 // Normalise accelerometer measurement 00818 norm = sqrtf(ax * ax + ay * ay + az * az); 00819 if (norm == 0.0f) return; // handle NaN 00820 norm = 1.0f / norm; // use reciprocal for division 00821 ax *= norm; 00822 ay *= norm; 00823 az *= norm; 00824 00825 // Normalise magnetometer measurement 00826 norm = sqrtf(mx * mx + my * my + mz * mz); 00827 if (norm == 0.0f) return; // handle NaN 00828 norm = 1.0f / norm; // use reciprocal for division 00829 mx *= norm; 00830 my *= norm; 00831 mz *= norm; 00832 00833 // Reference direction of Earth's magnetic field 00834 hx = 2.0f * mx * (0.5f - q3q3 - q4q4) + 2.0f * my * (q2q3 - q1q4) + 2.0f * mz * (q2q4 + q1q3); 00835 hy = 2.0f * mx * (q2q3 + q1q4) + 2.0f * my * (0.5f - q2q2 - q4q4) + 2.0f * mz * (q3q4 - q1q2); 00836 bx = sqrtf((hx * hx) + (hy * hy)); 00837 bz = 2.0f * mx * (q2q4 - q1q3) + 2.0f * my * (q3q4 + q1q2) + 2.0f * mz * (0.5f - q2q2 - q3q3); 00838 00839 // Estimated direction of gravity and magnetic field 00840 vx = 2.0f * (q2q4 - q1q3); 00841 vy = 2.0f * (q1q2 + q3q4); 00842 vz = q1q1 - q2q2 - q3q3 + q4q4; 00843 wx = 2.0f * bx * (0.5f - q3q3 - q4q4) + 2.0f * bz * (q2q4 - q1q3); 00844 wy = 2.0f * bx * (q2q3 - q1q4) + 2.0f * bz * (q1q2 + q3q4); 00845 wz = 2.0f * bx * (q1q3 + q2q4) + 2.0f * bz * (0.5f - q2q2 - q3q3); 00846 00847 // Error is cross product between estimated direction and measured direction of gravity 00848 ex = (ay * vz - az * vy) + (my * wz - mz * wy); 00849 ey = (az * vx - ax * vz) + (mz * wx - mx * wz); 00850 ez = (ax * vy - ay * vx) + (mx * wy - my * wx); 00851 if (Ki > 0.0f) 00852 { 00853 eInt[0] += ex; // accumulate integral error 00854 eInt[1] += ey; 00855 eInt[2] += ez; 00856 } 00857 else 00858 { 00859 eInt[0] = 0.0f; // prevent integral wind up 00860 eInt[1] = 0.0f; 00861 eInt[2] = 0.0f; 00862 } 00863 00864 // Apply feedback terms 00865 gx = gx + Kp * ex + Ki * eInt[0]; 00866 gy = gy + Kp * ey + Ki * eInt[1]; 00867 gz = gz + Kp * ez + Ki * eInt[2]; 00868 00869 // Integrate rate of change of quaternion 00870 pa = q2; 00871 pb = q3; 00872 pc = q4; 00873 q1 = q1 + (-q2 * gx - q3 * gy - q4 * gz) * (0.5f * deltat); 00874 q2 = pa + (q1 * gx + pb * gz - pc * gy) * (0.5f * deltat); 00875 q3 = pb + (q1 * gy - pa * gz + pc * gx) * (0.5f * deltat); 00876 q4 = pc + (q1 * gz + pa * gy - pb * gx) * (0.5f * deltat); 00877 00878 // Normalise quaternion 00879 norm = sqrtf(q1 * q1 + q2 * q2 + q3 * q3 + q4 * q4); 00880 norm = 1.0f / norm; 00881 q[0] = q1 * norm; 00882 q[1] = q2 * norm; 00883 q[2] = q3 * norm; 00884 q[3] = q4 * norm; 00885 00886 } 00887 }; 00888 #endif
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