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MPU9250.cpp
00001 #include "MPU9250.h" 00002 00003 00004 00005 uint8_t Ascale = AFS_2G; // AFS_2G, AFS_4G, AFS_8G, AFS_16G 00006 uint8_t Gscale = GFS_250DPS; // GFS_250DPS, GFS_500DPS, GFS_1000DPS, GFS_2000DPS 00007 uint8_t Mscale = MFS_16BITS; // MFS_14BITS or MFS_16BITS, 14-bit or 16-bit magnetometer resolution 00008 uint8_t Mmode = 0x06; // Either 8 Hz 0x02) or 100 Hz (0x06) magnetometer data ODR 00009 float aRes, gRes, mRes; // scale resolutions per LSB for the sensors 00010 00011 //Set up I2C, (SDA,SCL) 00012 I2C i2c(PB_9, PB_8); 00013 00014 DigitalOut myled(LED1); 00015 00016 // Pin definitions 00017 int intPin = 12; // These can be changed, 2 and 3 are the Arduinos ext int pins 00018 00019 int16_t accelCount[3]; // Stores the 16-bit signed accelerometer sensor output 00020 int16_t gyroCount[3]; // Stores the 16-bit signed gyro sensor output 00021 int16_t magCount[3]; // Stores the 16-bit signed magnetometer sensor output 00022 float magCalibration[3] = {0, 0, 0}, magbias[3] = {0, 0, 0}; // Factory mag calibration and mag bias 00023 float gyroBias[3] = {0, 0, 0}, accelBias[3] = {0, 0, 0}; // Bias corrections for gyro and accelerometer 00024 float ax, ay, az, gx, gy, gz, mx, my, mz; // variables to hold latest sensor data values 00025 int16_t tempCount; // Stores the real internal chip temperature in degrees Celsius 00026 float temperature; 00027 float SelfTest[6]; 00028 00029 int delt_t = 0; // used to control display output rate 00030 int _count = 0; // used to control display output rate 00031 00032 // parameters for 6 DoF sensor fusion calculations 00033 float PI = 3.14159265358979323846f; 00034 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 00035 float beta = sqrt(3.0f / 4.0f) * GyroMeasError; // compute beta 00036 float GyroMeasDrift = PI * (1.0f / 180.0f); // gyroscope measurement drift in rad/s/s (start at 0.0 deg/s/s) 00037 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 00038 #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 00039 #define Ki 0.0f 00040 00041 float pitch, yaw, roll; 00042 float vx, vy, vz; 00043 float deltat = 0.0f; // integration interval for both filter schemes 00044 int lastUpdate = 0, firstUpdate = 0, Now = 0; // used to calculate integration interval // used to calculate integration interval 00045 float q[4] = {1.0f, 0.0f, 0.0f, 0.0f}; // vector to hold quaternion 00046 float v_trans[3] = {0.0f, 0.0f, 0.0f}; // vector to hold translative velocities 00047 float a_old[3] = {0.00f, 0.00f, 0.00f}; 00048 float eInt[3] = {0.0f, 0.0f, 0.0f}; // vector to hold integral error for Mahony method 00049 00050 00051 accData_t myData; 00052 MPU9250 mpu9250; 00053 Timer t; 00054 Serial pc(USBTX, USBRX); // tx, rx 00055 00056 #define SAMPLE_TIME 100 00057 00058 00059 float sum = 0; 00060 uint32_t sumCount = 0; 00061 char buffer[14]; 00062 00063 00064 //=================================================================================================================== 00065 //====== Set of useful function to access acceleratio, gyroscope, and temperature data 00066 //=================================================================================================================== 00067 00068 void MPU9250::writeByte(uint8_t address, uint8_t subAddress, uint8_t data) 00069 { 00070 char data_write[2]; 00071 data_write[0] = subAddress; 00072 data_write[1] = data; 00073 i2c.write(address, data_write, 2, 0); 00074 } 00075 00076 char MPU9250::readByte(uint8_t address, uint8_t subAddress) 00077 { 00078 char data[1]; // `data` will store the register data 00079 char data_write[1]; 00080 data_write[0] = subAddress; 00081 i2c.write(address, data_write, 1, 1); // no stop 00082 i2c.read(address, data, 1, 0); 00083 return data[0]; 00084 } 00085 00086 void MPU9250::readBytes(uint8_t address, uint8_t subAddress, uint8_t count, uint8_t * dest) 00087 { 00088 char data[14]; 00089 char data_write[1]; 00090 data_write[0] = subAddress; 00091 i2c.write(address, data_write, 1, 1); // no stop 00092 i2c.read(address, data, count, 0); 00093 for(int ii = 0; ii < count; ii++) { 00094 dest[ii] = data[ii]; 00095 } 00096 } 00097 00098 00099 void MPU9250::getMres() 00100 { 00101 switch (Mscale) { 00102 // Possible magnetometer scales (and their register bit settings) are: 00103 // 14 bit resolution (0) and 16 bit resolution (1) 00104 case MFS_14BITS: 00105 mRes = 10.0*4219.0/8190.0; // Proper scale to return milliGauss 00106 break; 00107 case MFS_16BITS: 00108 mRes = 10.0*4219.0/32760.0; // Proper scale to return milliGauss 00109 break; 00110 } 00111 } 00112 00113 00114 void MPU9250::getGres() 00115 { 00116 switch (Gscale) { 00117 // Possible gyro scales (and their register bit settings) are: 00118 // 250 DPS (00), 500 DPS (01), 1000 DPS (10), and 2000 DPS (11). 00119 // Here's a bit of an algorith to calculate DPS/(ADC tick) based on that 2-bit value: 00120 case GFS_250DPS: 00121 gRes = 250.0/32768.0; 00122 break; 00123 case GFS_500DPS: 00124 gRes = 500.0/32768.0; 00125 break; 00126 case GFS_1000DPS: 00127 gRes = 1000.0/32768.0; 00128 break; 00129 case GFS_2000DPS: 00130 gRes = 2000.0/32768.0; 00131 break; 00132 } 00133 } 00134 00135 00136 void MPU9250::getAres() 00137 { 00138 switch (Ascale) { 00139 // Possible accelerometer scales (and their register bit settings) are: 00140 // 2 Gs (00), 4 Gs (01), 8 Gs (10), and 16 Gs (11). 00141 // Here's a bit of an algorith to calculate DPS/(ADC tick) based on that 2-bit value: 00142 case AFS_2G: 00143 aRes = 2.0/32768.0; 00144 break; 00145 case AFS_4G: 00146 aRes = 4.0/32768.0; 00147 break; 00148 case AFS_8G: 00149 aRes = 8.0/32768.0; 00150 break; 00151 case AFS_16G: 00152 aRes = 16.0/32768.0; 00153 break; 00154 } 00155 } 00156 00157 00158 void MPU9250::readAccelData(int16_t * destination) 00159 { 00160 uint8_t rawData[6]; // x/y/z accel register data stored here 00161 readBytes(MPU9250_ADDRESS, ACCEL_XOUT_H, 6, &rawData[0]); // Read the six raw data registers into data array 00162 destination[0] = (int16_t)(((int16_t)rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value 00163 destination[1] = (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ; 00164 destination[2] = (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ; 00165 } 00166 00167 void MPU9250::readGyroData(int16_t * destination) 00168 { 00169 uint8_t rawData[6]; // x/y/z gyro register data stored here 00170 readBytes(MPU9250_ADDRESS, GYRO_XOUT_H, 6, &rawData[0]); // Read the six raw data registers sequentially into data array 00171 destination[0] = (int16_t)(((int16_t)rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value 00172 destination[1] = (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ; 00173 destination[2] = (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ; 00174 } 00175 00176 void MPU9250::readMagData(int16_t * destination) 00177 { 00178 uint8_t rawData[7]; // x/y/z gyro register data, ST2 register stored here, must read ST2 at end of data acquisition 00179 if(readByte(AK8963_ADDRESS, AK8963_ST1) & 0x01) { // wait for magnetometer data ready bit to be set 00180 readBytes(AK8963_ADDRESS, AK8963_XOUT_L, 7, &rawData[0]); // Read the six raw data and ST2 registers sequentially into data array 00181 uint8_t c = rawData[6]; // End data read by reading ST2 register 00182 if(!(c & 0x08)) { // Check if magnetic sensor overflow set, if not then report data 00183 destination[0] = (int16_t)(((int16_t)rawData[1] << 8) | rawData[0]); // Turn the MSB and LSB into a signed 16-bit value 00184 destination[1] = (int16_t)(((int16_t)rawData[3] << 8) | rawData[2]) ; // Data stored as little Endian 00185 destination[2] = (int16_t)(((int16_t)rawData[5] << 8) | rawData[4]) ; 00186 } 00187 } 00188 } 00189 00190 int16_t MPU9250::readTempData() 00191 { 00192 uint8_t rawData[2]; // x/y/z gyro register data stored here 00193 readBytes(MPU9250_ADDRESS, TEMP_OUT_H, 2, &rawData[0]); // Read the two raw data registers sequentially into data array 00194 return (int16_t)(((int16_t)rawData[0]) << 8 | rawData[1]) ; // Turn the MSB and LSB into a 16-bit value 00195 } 00196 00197 00198 void MPU9250::resetMPU9250() 00199 { 00200 // reset device 00201 writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x80); // Write a one to bit 7 reset bit; toggle reset device 00202 wait(0.1); 00203 } 00204 00205 void MPU9250::initAK8963(float * destination) 00206 { 00207 // First extract the factory calibration for each magnetometer axis 00208 uint8_t rawData[3]; // x/y/z gyro calibration data stored here 00209 writeByte(AK8963_ADDRESS, AK8963_CNTL, 0x00); // Power down magnetometer 00210 wait(0.01); 00211 writeByte(AK8963_ADDRESS, AK8963_CNTL, 0x0F); // Enter Fuse ROM access mode 00212 wait(0.01); 00213 readBytes(AK8963_ADDRESS, AK8963_ASAX, 3, &rawData[0]); // Read the x-, y-, and z-axis calibration values 00214 destination[0] = (float)(rawData[0] - 128)/256.0f + 1.0f; // Return x-axis sensitivity adjustment values, etc. 00215 destination[1] = (float)(rawData[1] - 128)/256.0f + 1.0f; 00216 destination[2] = (float)(rawData[2] - 128)/256.0f + 1.0f; 00217 writeByte(AK8963_ADDRESS, AK8963_CNTL, 0x00); // Power down magnetometer 00218 wait(0.01); 00219 // Configure the magnetometer for continuous read and highest resolution 00220 // set Mscale bit 4 to 1 (0) to enable 16 (14) bit resolution in CNTL register, 00221 // and enable continuous mode data acquisition Mmode (bits [3:0]), 0010 for 8 Hz and 0110 for 100 Hz sample rates 00222 writeByte(AK8963_ADDRESS, AK8963_CNTL, Mscale << 4 | Mmode); // Set magnetometer data resolution and sample ODR 00223 wait(0.01); 00224 } 00225 00226 00227 void MPU9250::initMPU9250() 00228 { 00229 // Initialize MPU9250 device 00230 // wake up device 00231 writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x00); // Clear sleep mode bit (6), enable all sensors 00232 wait(0.1); // Delay 100 ms for PLL to get established on x-axis gyro; should check for PLL ready interrupt 00233 00234 // get stable time source 00235 writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x01); // Set clock source to be PLL with x-axis gyroscope reference, bits 2:0 = 001 00236 00237 // Configure Gyro and Accelerometer 00238 // Disable FSYNC and set accelerometer and gyro bandwidth to 44 and 42 Hz, respectively; 00239 // DLPF_CFG = bits 2:0 = 010; this sets the sample rate at 1 kHz for both 00240 // Maximum delay is 4.9 ms which is just over a 200 Hz maximum rate 00241 writeByte(MPU9250_ADDRESS, CONFIG, 0x03); 00242 00243 // Set sample rate = gyroscope output rate/(1 + SMPLRT_DIV) 00244 writeByte(MPU9250_ADDRESS, SMPLRT_DIV, 0x04); // Use a 200 Hz rate; the same rate set in CONFIG above 00245 00246 // Set gyroscope full scale range 00247 // Range selects FS_SEL and AFS_SEL are 0 - 3, so 2-bit values are left-shifted into positions 4:3 00248 uint8_t c = readByte(MPU9250_ADDRESS, GYRO_CONFIG); 00249 writeByte(MPU9250_ADDRESS, GYRO_CONFIG, c & ~0xE0); // Clear self-test bits [7:5] 00250 writeByte(MPU9250_ADDRESS, GYRO_CONFIG, c & ~0x18); // Clear AFS bits [4:3] 00251 writeByte(MPU9250_ADDRESS, GYRO_CONFIG, c | Gscale << 3); // Set full scale range for the gyro 00252 00253 // Set accelerometer configuration 00254 c = readByte(MPU9250_ADDRESS, ACCEL_CONFIG); 00255 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, c & ~0xE0); // Clear self-test bits [7:5] 00256 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, c & ~0x18); // Clear AFS bits [4:3] 00257 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, c | Ascale << 3); // Set full scale range for the accelerometer 00258 00259 // Set accelerometer sample rate configuration 00260 // It is possible to get a 4 kHz sample rate from the accelerometer by choosing 1 for 00261 // accel_fchoice_b bit [3]; in this case the bandwidth is 1.13 kHz 00262 c = readByte(MPU9250_ADDRESS, ACCEL_CONFIG2); 00263 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG2, c & ~0x0F); // Clear accel_fchoice_b (bit 3) and A_DLPFG (bits [2:0]) 00264 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG2, c | 0x03); // Set accelerometer rate to 1 kHz and bandwidth to 41 Hz 00265 00266 // The accelerometer, gyro, and thermometer are set to 1 kHz sample rates, 00267 // but all these rates are further reduced by a factor of 5 to 200 Hz because of the SMPLRT_DIV setting 00268 00269 // Configure Interrupts and Bypass Enable 00270 // Set interrupt pin active high, push-pull, and clear on read of INT_STATUS, enable I2C_BYPASS_EN so additional chips 00271 // can join the I2C bus and all can be controlled by the Arduino as master 00272 writeByte(MPU9250_ADDRESS, INT_PIN_CFG, 0x22); 00273 writeByte(MPU9250_ADDRESS, INT_ENABLE, 0x01); // Enable data ready (bit 0) interrupt 00274 } 00275 00276 // Function which accumulates gyro and accelerometer data after device initialization. It calculates the average 00277 // of the at-rest readings and then loads the resulting offsets into accelerometer and gyro bias registers. 00278 void MPU9250::calibrateMPU9250(float * dest1, float * dest2) 00279 { 00280 uint8_t data[12]; // data array to hold accelerometer and gyro x, y, z, data 00281 uint16_t ii, packet_count, fifo_count; 00282 int32_t gyro_bias[3] = {0, 0, 0}, accel_bias[3] = {0, 0, 0}; 00283 00284 // reset device, reset all registers, clear gyro and accelerometer bias registers 00285 writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x80); // Write a one to bit 7 reset bit; toggle reset device 00286 wait(0.1); 00287 00288 // get stable time source 00289 // Set clock source to be PLL with x-axis gyroscope reference, bits 2:0 = 001 00290 writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x01); 00291 writeByte(MPU9250_ADDRESS, PWR_MGMT_2, 0x00); 00292 wait(0.2); 00293 00294 // Configure device for bias calculation 00295 writeByte(MPU9250_ADDRESS, INT_ENABLE, 0x00); // Disable all interrupts 00296 writeByte(MPU9250_ADDRESS, FIFO_EN, 0x00); // Disable FIFO 00297 writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x00); // Turn on internal clock source 00298 writeByte(MPU9250_ADDRESS, I2C_MST_CTRL, 0x00); // Disable I2C master 00299 writeByte(MPU9250_ADDRESS, USER_CTRL, 0x00); // Disable FIFO and I2C master modes 00300 writeByte(MPU9250_ADDRESS, USER_CTRL, 0x0C); // Reset FIFO and DMP 00301 wait(0.015); 00302 00303 // Configure MPU9250 gyro and accelerometer for bias calculation 00304 writeByte(MPU9250_ADDRESS, CONFIG, 0x01); // Set low-pass filter to 188 Hz 00305 writeByte(MPU9250_ADDRESS, SMPLRT_DIV, 0x00); // Set sample rate to 1 kHz 00306 writeByte(MPU9250_ADDRESS, GYRO_CONFIG, 0x00); // Set gyro full-scale to 250 degrees per second, maximum sensitivity 00307 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, 0x00); // Set accelerometer full-scale to 2 g, maximum sensitivity 00308 00309 uint16_t gyrosensitivity = 131; // = 131 LSB/degrees/sec 00310 uint16_t accelsensitivity = 16384; // = 16384 LSB/g 00311 00312 // Configure FIFO to capture accelerometer and gyro data for bias calculation 00313 writeByte(MPU9250_ADDRESS, USER_CTRL, 0x40); // Enable FIFO 00314 writeByte(MPU9250_ADDRESS, FIFO_EN, 0x78); // Enable gyro and accelerometer sensors for FIFO (max size 512 bytes in MPU-9250) 00315 wait(0.04); // accumulate 40 samples in 80 milliseconds = 480 bytes 00316 00317 // At end of sample accumulation, turn off FIFO sensor read 00318 writeByte(MPU9250_ADDRESS, FIFO_EN, 0x00); // Disable gyro and accelerometer sensors for FIFO 00319 readBytes(MPU9250_ADDRESS, FIFO_COUNTH, 2, &data[0]); // read FIFO sample count 00320 fifo_count = ((uint16_t)data[0] << 8) | data[1]; 00321 packet_count = fifo_count/12;// How many sets of full gyro and accelerometer data for averaging 00322 00323 for (ii = 0; ii < packet_count; ii++) { 00324 int16_t accel_temp[3] = {0, 0, 0}, gyro_temp[3] = {0, 0, 0}; 00325 readBytes(MPU9250_ADDRESS, FIFO_R_W, 12, &data[0]); // read data for averaging 00326 accel_temp[0] = (int16_t) (((int16_t)data[0] << 8) | data[1] ) ; // Form signed 16-bit integer for each sample in FIFO 00327 accel_temp[1] = (int16_t) (((int16_t)data[2] << 8) | data[3] ) ; 00328 accel_temp[2] = (int16_t) (((int16_t)data[4] << 8) | data[5] ) ; 00329 gyro_temp[0] = (int16_t) (((int16_t)data[6] << 8) | data[7] ) ; 00330 gyro_temp[1] = (int16_t) (((int16_t)data[8] << 8) | data[9] ) ; 00331 gyro_temp[2] = (int16_t) (((int16_t)data[10] << 8) | data[11]) ; 00332 00333 accel_bias[0] += (int32_t) accel_temp[0]; // Sum individual signed 16-bit biases to get accumulated signed 32-bit biases 00334 accel_bias[1] += (int32_t) accel_temp[1]; 00335 accel_bias[2] += (int32_t) accel_temp[2]; 00336 gyro_bias[0] += (int32_t) gyro_temp[0]; 00337 gyro_bias[1] += (int32_t) gyro_temp[1]; 00338 gyro_bias[2] += (int32_t) gyro_temp[2]; 00339 00340 } 00341 accel_bias[0] /= (int32_t) packet_count; // Normalize sums to get average count biases 00342 accel_bias[1] /= (int32_t) packet_count; 00343 accel_bias[2] /= (int32_t) packet_count; 00344 gyro_bias[0] /= (int32_t) packet_count; 00345 gyro_bias[1] /= (int32_t) packet_count; 00346 gyro_bias[2] /= (int32_t) packet_count; 00347 00348 if(accel_bias[2] > 0L) { 00349 accel_bias[2] -= (int32_t) accelsensitivity; // Remove gravity from the z-axis accelerometer bias calculation 00350 } else { 00351 accel_bias[2] += (int32_t) accelsensitivity; 00352 } 00353 00354 // Construct the gyro biases for push to the hardware gyro bias registers, which are reset to zero upon device startup 00355 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 00356 data[1] = (-gyro_bias[0]/4) & 0xFF; // Biases are additive, so change sign on calculated average gyro biases 00357 data[2] = (-gyro_bias[1]/4 >> 8) & 0xFF; 00358 data[3] = (-gyro_bias[1]/4) & 0xFF; 00359 data[4] = (-gyro_bias[2]/4 >> 8) & 0xFF; 00360 data[5] = (-gyro_bias[2]/4) & 0xFF; 00361 00362 /// Push gyro biases to hardware registers 00363 /* writeByte(MPU9250_ADDRESS, XG_OFFSET_H, data[0]); 00364 writeByte(MPU9250_ADDRESS, XG_OFFSET_L, data[1]); 00365 writeByte(MPU9250_ADDRESS, YG_OFFSET_H, data[2]); 00366 writeByte(MPU9250_ADDRESS, YG_OFFSET_L, data[3]); 00367 writeByte(MPU9250_ADDRESS, ZG_OFFSET_H, data[4]); 00368 writeByte(MPU9250_ADDRESS, ZG_OFFSET_L, data[5]); 00369 */ 00370 dest1[0] = (float) gyro_bias[0]/(float) gyrosensitivity; // construct gyro bias in deg/s for later manual subtraction 00371 dest1[1] = (float) gyro_bias[1]/(float) gyrosensitivity; 00372 dest1[2] = (float) gyro_bias[2]/(float) gyrosensitivity; 00373 00374 // Construct the accelerometer biases for push to the hardware accelerometer bias registers. These registers contain 00375 // factory trim values which must be added to the calculated accelerometer biases; on boot up these registers will hold 00376 // non-zero values. In addition, bit 0 of the lower byte must be preserved since it is used for temperature 00377 // compensation calculations. Accelerometer bias registers expect bias input as 2048 LSB per g, so that 00378 // the accelerometer biases calculated above must be divided by 8. 00379 00380 int32_t accel_bias_reg[3] = {0, 0, 0}; // A place to hold the factory accelerometer trim biases 00381 readBytes(MPU9250_ADDRESS, XA_OFFSET_H, 2, &data[0]); // Read factory accelerometer trim values 00382 accel_bias_reg[0] = (int16_t) ((int16_t)data[0] << 8) | data[1]; 00383 readBytes(MPU9250_ADDRESS, YA_OFFSET_H, 2, &data[0]); 00384 accel_bias_reg[1] = (int16_t) ((int16_t)data[0] << 8) | data[1]; 00385 readBytes(MPU9250_ADDRESS, ZA_OFFSET_H, 2, &data[0]); 00386 accel_bias_reg[2] = (int16_t) ((int16_t)data[0] << 8) | data[1]; 00387 00388 uint32_t mask = 1uL; // Define mask for temperature compensation bit 0 of lower byte of accelerometer bias registers 00389 uint8_t mask_bit[3] = {0, 0, 0}; // Define array to hold mask bit for each accelerometer bias axis 00390 00391 for(ii = 0; ii < 3; ii++) { 00392 if(accel_bias_reg[ii] & mask) mask_bit[ii] = 0x01; // If temperature compensation bit is set, record that fact in mask_bit 00393 } 00394 00395 // Construct total accelerometer bias, including calculated average accelerometer bias from above 00396 accel_bias_reg[0] -= (accel_bias[0]/8); // Subtract calculated averaged accelerometer bias scaled to 2048 LSB/g (16 g full scale) 00397 accel_bias_reg[1] -= (accel_bias[1]/8); 00398 accel_bias_reg[2] -= (accel_bias[2]/8); 00399 00400 data[0] = (accel_bias_reg[0] >> 8) & 0xFF; 00401 data[1] = (accel_bias_reg[0]) & 0xFF; 00402 data[1] = data[1] | mask_bit[0]; // preserve temperature compensation bit when writing back to accelerometer bias registers 00403 data[2] = (accel_bias_reg[1] >> 8) & 0xFF; 00404 data[3] = (accel_bias_reg[1]) & 0xFF; 00405 data[3] = data[3] | mask_bit[1]; // preserve temperature compensation bit when writing back to accelerometer bias registers 00406 data[4] = (accel_bias_reg[2] >> 8) & 0xFF; 00407 data[5] = (accel_bias_reg[2]) & 0xFF; 00408 data[5] = data[5] | mask_bit[2]; // preserve temperature compensation bit when writing back to accelerometer bias registers 00409 00410 // Apparently this is not working for the acceleration biases in the MPU-9250 00411 // Are we handling the temperature correction bit properly? 00412 // Push accelerometer biases to hardware registers 00413 /* writeByte(MPU9250_ADDRESS, XA_OFFSET_H, data[0]); 00414 writeByte(MPU9250_ADDRESS, XA_OFFSET_L, data[1]); 00415 writeByte(MPU9250_ADDRESS, YA_OFFSET_H, data[2]); 00416 writeByte(MPU9250_ADDRESS, YA_OFFSET_L, data[3]); 00417 writeByte(MPU9250_ADDRESS, ZA_OFFSET_H, data[4]); 00418 writeByte(MPU9250_ADDRESS, ZA_OFFSET_L, data[5]); 00419 */ 00420 // Output scaled accelerometer biases for manual subtraction in the main program 00421 dest2[0] = (float)accel_bias[0]/(float)accelsensitivity; 00422 dest2[1] = (float)accel_bias[1]/(float)accelsensitivity; 00423 dest2[2] = (float)accel_bias[2]/(float)accelsensitivity; 00424 } 00425 00426 00427 // Accelerometer and gyroscope self test; check calibration wrt factory settings 00428 void MPU9250::MPU9250SelfTest(float * destination) // Should return percent deviation from factory trim values, +/- 14 or less deviation is a pass 00429 { 00430 uint8_t rawData[6] = {0, 0, 0, 0, 0, 0}; 00431 uint8_t selfTest[6]; 00432 int16_t gAvg[3], aAvg[3], aSTAvg[3], gSTAvg[3]; 00433 float factoryTrim[6]; 00434 uint8_t FS = 0; 00435 00436 writeByte(MPU9250_ADDRESS, SMPLRT_DIV, 0x00); // Set gyro sample rate to 1 kHz 00437 writeByte(MPU9250_ADDRESS, CONFIG, 0x02); // Set gyro sample rate to 1 kHz and DLPF to 92 Hz 00438 writeByte(MPU9250_ADDRESS, GYRO_CONFIG, 1<<FS); // Set full scale range for the gyro to 250 dps 00439 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG2, 0x02); // Set accelerometer rate to 1 kHz and bandwidth to 92 Hz 00440 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, 1<<FS); // Set full scale range for the accelerometer to 2 g 00441 00442 for( int ii = 0; ii < 200; ii++) { // get average current values of gyro and acclerometer 00443 00444 readBytes(MPU9250_ADDRESS, ACCEL_XOUT_H, 6, &rawData[0]); // Read the six raw data registers into data array 00445 aAvg[0] += (int16_t)(((int16_t)rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value 00446 aAvg[1] += (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ; 00447 aAvg[2] += (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ; 00448 00449 readBytes(MPU9250_ADDRESS, GYRO_XOUT_H, 6, &rawData[0]); // Read the six raw data registers sequentially into data array 00450 gAvg[0] += (int16_t)(((int16_t)rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value 00451 gAvg[1] += (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ; 00452 gAvg[2] += (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ; 00453 } 00454 00455 for (int ii =0; ii < 3; ii++) { // Get average of 200 values and store as average current readings 00456 aAvg[ii] /= 200; 00457 gAvg[ii] /= 200; 00458 } 00459 00460 // Configure the accelerometer for self-test 00461 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, 0xE0); // Enable self test on all three axes and set accelerometer range to +/- 2 g 00462 writeByte(MPU9250_ADDRESS, GYRO_CONFIG, 0xE0); // Enable self test on all three axes and set gyro range to +/- 250 degrees/s 00463 wait(0.025); // Delay a while to let the device stabilize 00464 00465 for( int ii = 0; ii < 200; ii++) { // get average self-test values of gyro and acclerometer 00466 00467 readBytes(MPU9250_ADDRESS, ACCEL_XOUT_H, 6, &rawData[0]); // Read the six raw data registers into data array 00468 aSTAvg[0] += (int16_t)(((int16_t)rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value 00469 aSTAvg[1] += (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ; 00470 aSTAvg[2] += (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ; 00471 00472 readBytes(MPU9250_ADDRESS, GYRO_XOUT_H, 6, &rawData[0]); // Read the six raw data registers sequentially into data array 00473 gSTAvg[0] += (int16_t)(((int16_t)rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value 00474 gSTAvg[1] += (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ; 00475 gSTAvg[2] += (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ; 00476 } 00477 00478 for (int ii =0; ii < 3; ii++) { // Get average of 200 values and store as average self-test readings 00479 aSTAvg[ii] /= 200; 00480 gSTAvg[ii] /= 200; 00481 } 00482 00483 // Configure the gyro and accelerometer for normal operation 00484 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, 0x00); 00485 writeByte(MPU9250_ADDRESS, GYRO_CONFIG, 0x00); 00486 wait(0.025); // Delay a while to let the device stabilize 00487 00488 // Retrieve accelerometer and gyro factory Self-Test Code from USR_Reg 00489 selfTest[0] = readByte(MPU9250_ADDRESS, SELF_TEST_X_ACCEL); // X-axis accel self-test results 00490 selfTest[1] = readByte(MPU9250_ADDRESS, SELF_TEST_Y_ACCEL); // Y-axis accel self-test results 00491 selfTest[2] = readByte(MPU9250_ADDRESS, SELF_TEST_Z_ACCEL); // Z-axis accel self-test results 00492 selfTest[3] = readByte(MPU9250_ADDRESS, SELF_TEST_X_GYRO); // X-axis gyro self-test results 00493 selfTest[4] = readByte(MPU9250_ADDRESS, SELF_TEST_Y_GYRO); // Y-axis gyro self-test results 00494 selfTest[5] = readByte(MPU9250_ADDRESS, SELF_TEST_Z_GYRO); // Z-axis gyro self-test results 00495 00496 // Retrieve factory self-test value from self-test code reads 00497 factoryTrim[0] = (float)(2620/1<<FS)*(pow( 1.01, ((float)selfTest[0] - 1.0) )); // FT[Xa] factory trim calculation 00498 factoryTrim[1] = (float)(2620/1<<FS)*(pow( 1.01, ((float)selfTest[1] - 1.0) )); // FT[Ya] factory trim calculation 00499 factoryTrim[2] = (float)(2620/1<<FS)*(pow( 1.01, ((float)selfTest[2] - 1.0) )); // FT[Za] factory trim calculation 00500 factoryTrim[3] = (float)(2620/1<<FS)*(pow( 1.01, ((float)selfTest[3] - 1.0) )); // FT[Xg] factory trim calculation 00501 factoryTrim[4] = (float)(2620/1<<FS)*(pow( 1.01, ((float)selfTest[4] - 1.0) )); // FT[Yg] factory trim calculation 00502 factoryTrim[5] = (float)(2620/1<<FS)*(pow( 1.01, ((float)selfTest[5] - 1.0) )); // FT[Zg] factory trim calculation 00503 00504 // Report results as a ratio of (STR - FT)/FT; the change from Factory Trim of the Self-Test Response 00505 // To get percent, must multiply by 100 00506 for (int i = 0; i < 3; i++) { 00507 destination[i] = 100.0*((float)(aSTAvg[i] - aAvg[i]))/factoryTrim[i]; // Report percent differences 00508 destination[i+3] = 100.0*((float)(gSTAvg[i] - gAvg[i]))/factoryTrim[i+3]; // Report percent differences 00509 } 00510 00511 } 00512 00513 00514 00515 // Implementation of Sebastian Madgwick's "...efficient orientation filter for... inertial/magnetic sensor arrays" 00516 // (see http://www.x-io.co.uk/category/open-source/ for examples and more details) 00517 // which fuses acceleration, rotation rate, and magnetic moments to produce a quaternion-based estimate of absolute 00518 // device orientation -- which can be converted to yaw, pitch, and roll. Useful for stabilizing quadcopters, etc. 00519 // The performance of the orientation filter is at least as good as conventional Kalman-based filtering algorithms 00520 // but is much less computationally intensive---it can be performed on a 3.3 V Pro Mini operating at 8 MHz! 00521 void MPU9250::MadgwickQuaternionUpdate(float ax, float ay, float az, float gx, float gy, float gz, float mx, float my, float mz) 00522 { 00523 float q1 = q[0], q2 = q[1], q3 = q[2], q4 = q[3]; // short name local variable for readability 00524 float norm; 00525 float hx, hy, _2bx, _2bz; 00526 float s1, s2, s3, s4; 00527 float qDot1, qDot2, qDot3, qDot4; 00528 00529 // Auxiliary variables to avoid repeated arithmetic 00530 float _2q1mx; 00531 float _2q1my; 00532 float _2q1mz; 00533 float _2q2mx; 00534 float _4bx; 00535 float _4bz; 00536 float _2q1 = 2.0f * q1; 00537 float _2q2 = 2.0f * q2; 00538 float _2q3 = 2.0f * q3; 00539 float _2q4 = 2.0f * q4; 00540 float _2q1q3 = 2.0f * q1 * q3; 00541 float _2q3q4 = 2.0f * q3 * q4; 00542 float q1q1 = q1 * q1; 00543 float q1q2 = q1 * q2; 00544 float q1q3 = q1 * q3; 00545 float q1q4 = q1 * q4; 00546 float q2q2 = q2 * q2; 00547 float q2q3 = q2 * q3; 00548 float q2q4 = q2 * q4; 00549 float q3q3 = q3 * q3; 00550 float q3q4 = q3 * q4; 00551 float q4q4 = q4 * q4; 00552 00553 // Normalise accelerometer measurement 00554 norm = sqrt(ax * ax + ay * ay + az * az); 00555 if (norm == 0.0f) return; // handle NaN 00556 norm = 1.0f/norm; 00557 ax *= norm; 00558 ay *= norm; 00559 az *= norm; 00560 00561 // Normalise magnetometer measurement 00562 norm = sqrt(mx * mx + my * my + mz * mz); 00563 if (norm == 0.0f) return; // handle NaN 00564 norm = 1.0f/norm; 00565 mx *= norm; 00566 my *= norm; 00567 mz *= norm; 00568 00569 // Reference direction of Earth's magnetic field 00570 _2q1mx = 2.0f * q1 * mx; 00571 _2q1my = 2.0f * q1 * my; 00572 _2q1mz = 2.0f * q1 * mz; 00573 _2q2mx = 2.0f * q2 * mx; 00574 hx = mx * q1q1 - _2q1my * q4 + _2q1mz * q3 + mx * q2q2 + _2q2 * my * q3 + _2q2 * mz * q4 - mx * q3q3 - mx * q4q4; 00575 hy = _2q1mx * q4 + my * q1q1 - _2q1mz * q2 + _2q2mx * q3 - my * q2q2 + my * q3q3 + _2q3 * mz * q4 - my * q4q4; 00576 _2bx = sqrt(hx * hx + hy * hy); 00577 _2bz = -_2q1mx * q3 + _2q1my * q2 + mz * q1q1 + _2q2mx * q4 - mz * q2q2 + _2q3 * my * q4 - mz * q3q3 + mz * q4q4; 00578 _4bx = 2.0f * _2bx; 00579 _4bz = 2.0f * _2bz; 00580 00581 // Gradient decent algorithm corrective step 00582 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); 00583 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); 00584 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); 00585 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); 00586 norm = sqrt(s1 * s1 + s2 * s2 + s3 * s3 + s4 * s4); // normalise step magnitude 00587 norm = 1.0f/norm; 00588 s1 *= norm; 00589 s2 *= norm; 00590 s3 *= norm; 00591 s4 *= norm; 00592 00593 // Compute rate of change of quaternion 00594 qDot1 = 0.5f * (-q2 * gx - q3 * gy - q4 * gz) - beta * s1; 00595 qDot2 = 0.5f * (q1 * gx + q3 * gz - q4 * gy) - beta * s2; 00596 qDot3 = 0.5f * (q1 * gy - q2 * gz + q4 * gx) - beta * s3; 00597 qDot4 = 0.5f * (q1 * gz + q2 * gy - q3 * gx) - beta * s4; 00598 00599 // Integrate to yield quaternion 00600 q1 += qDot1 * deltat; 00601 q2 += qDot2 * deltat; 00602 q3 += qDot3 * deltat; 00603 q4 += qDot4 * deltat; 00604 norm = sqrt(q1 * q1 + q2 * q2 + q3 * q3 + q4 * q4); // normalise quaternion 00605 norm = 1.0f/norm; 00606 q[0] = q1 * norm; 00607 q[1] = q2 * norm; 00608 q[2] = q3 * norm; 00609 q[3] = q4 * norm; 00610 00611 } 00612 00613 00614 00615 // Similar to Madgwick scheme but uses proportional and integral filtering on the error between estimated reference vectors and 00616 // measured ones. 00617 void MPU9250::MahonyQuaternionUpdate(float ax, float ay, float az, float gx, float gy, float gz, float mx, float my, float mz) 00618 { 00619 float q1 = q[0], q2 = q[1], q3 = q[2], q4 = q[3]; // short name local variable for readability 00620 float norm; 00621 float hx, hy, bx, bz; 00622 float vx, vy, vz, wx, wy, wz; 00623 float ex, ey, ez; 00624 float pa, pb, pc; 00625 00626 // Auxiliary variables to avoid repeated arithmetic 00627 float q1q1 = q1 * q1; 00628 float q1q2 = q1 * q2; 00629 float q1q3 = q1 * q3; 00630 float q1q4 = q1 * q4; 00631 float q2q2 = q2 * q2; 00632 float q2q3 = q2 * q3; 00633 float q2q4 = q2 * q4; 00634 float q3q3 = q3 * q3; 00635 float q3q4 = q3 * q4; 00636 float q4q4 = q4 * q4; 00637 00638 // Normalise accelerometer measurement 00639 norm = sqrt(ax * ax + ay * ay + az * az); 00640 if (norm == 0.0f) return; // handle NaN 00641 norm = 1.0f / norm; // use reciprocal for division 00642 ax *= norm; 00643 ay *= norm; 00644 az *= norm; 00645 00646 // Normalise magnetometer measurement 00647 norm = sqrt(mx * mx + my * my + mz * mz); 00648 if (norm == 0.0f) return; // handle NaN 00649 norm = 1.0f / norm; // use reciprocal for division 00650 mx *= norm; 00651 my *= norm; 00652 mz *= norm; 00653 00654 // Reference direction of Earth's magnetic field 00655 hx = 2.0f * mx * (0.5f - q3q3 - q4q4) + 2.0f * my * (q2q3 - q1q4) + 2.0f * mz * (q2q4 + q1q3); 00656 hy = 2.0f * mx * (q2q3 + q1q4) + 2.0f * my * (0.5f - q2q2 - q4q4) + 2.0f * mz * (q3q4 - q1q2); 00657 bx = sqrt((hx * hx) + (hy * hy)); 00658 bz = 2.0f * mx * (q2q4 - q1q3) + 2.0f * my * (q3q4 + q1q2) + 2.0f * mz * (0.5f - q2q2 - q3q3); 00659 00660 // Estimated direction of gravity and magnetic field 00661 vx = 2.0f * (q2q4 - q1q3); 00662 vy = 2.0f * (q1q2 + q3q4); 00663 vz = q1q1 - q2q2 - q3q3 + q4q4; 00664 wx = 2.0f * bx * (0.5f - q3q3 - q4q4) + 2.0f * bz * (q2q4 - q1q3); 00665 wy = 2.0f * bx * (q2q3 - q1q4) + 2.0f * bz * (q1q2 + q3q4); 00666 wz = 2.0f * bx * (q1q3 + q2q4) + 2.0f * bz * (0.5f - q2q2 - q3q3); 00667 00668 // Error is cross product between estimated direction and measured direction of gravity 00669 ex = (ay * vz - az * vy) + (my * wz - mz * wy); 00670 ey = (az * vx - ax * vz) + (mz * wx - mx * wz); 00671 ez = (ax * vy - ay * vx) + (mx * wy - my * wx); 00672 if (Ki > 0.0f) { 00673 eInt[0] += ex; // accumulate integral error 00674 eInt[1] += ey; 00675 eInt[2] += ez; 00676 } else { 00677 eInt[0] = 0.0f; // prevent integral wind up 00678 eInt[1] = 0.0f; 00679 eInt[2] = 0.0f; 00680 } 00681 00682 // Apply feedback terms 00683 gx = gx + Kp * ex + Ki * eInt[0]; 00684 gy = gy + Kp * ey + Ki * eInt[1]; 00685 gz = gz + Kp * ez + Ki * eInt[2]; 00686 00687 // Integrate rate of change of quaternion 00688 pa = q2; 00689 pb = q3; 00690 pc = q4; 00691 q1 = q1 + (-q2 * gx - q3 * gy - q4 * gz) * (0.5f * deltat); 00692 q2 = pa + (q1 * gx + pb * gz - pc * gy) * (0.5f * deltat); 00693 q3 = pb + (q1 * gy - pa * gz + pc * gx) * (0.5f * deltat); 00694 q4 = pc + (q1 * gz + pa * gy - pb * gx) * (0.5f * deltat); 00695 00696 // Normalise quaternion 00697 norm = sqrt(q1 * q1 + q2 * q2 + q3 * q3 + q4 * q4); 00698 norm = 1.0f / norm; 00699 q[0] = q1 * norm; 00700 q[1] = q2 * norm; 00701 q[2] = q3 * norm; 00702 q[3] = q4 * norm; 00703 00704 } 00705 00706 // Integrates the acceleration to get the boards translative velocity 00707 void MPU9250::velocityUpdate(float ax, float ay, float az) 00708 { 00709 // short name local variable for readability 00710 00711 v_trans[0] = deltat*0.5*(a_old[0] + ax*GRAVITATION) + v_trans[0]; 00712 v_trans[1] = deltat*0.5*(a_old[1] + ay*GRAVITATION) + v_trans[1]; 00713 v_trans[2] = deltat*0.5*(a_old[2] + az*GRAVITATION + GRAVITATION) + v_trans[2]; 00714 00715 a_old[0] = ax*GRAVITATION; 00716 a_old[1] = ay*GRAVITATION; 00717 a_old[2] = az*GRAVITATION; 00718 } 00719 00720 void MPU9250::readIMU() 00721 { 00722 // If intPin goes high, all data registers have new data 00723 if(mpu9250.readByte(MPU9250_ADDRESS, INT_STATUS) & 0x01) { // On interrupt, check if data ready interrupt 00724 00725 mpu9250.readAccelData(accelCount); // Read the x/y/z adc values 00726 // Now we'll calculate the accleration value into actual g's 00727 ax = (float)accelCount[0]*aRes - accelBias[0]; // get actual g value, this depends on scale being set 00728 ay = (float)accelCount[1]*aRes - accelBias[1]; 00729 az = (float)accelCount[2]*aRes - accelBias[2]; 00730 00731 mpu9250.readGyroData(gyroCount); // Read the x/y/z adc values 00732 // Calculate the gyro value into actual degrees per second 00733 gx = (float)gyroCount[0]*gRes - gyroBias[0]; // get actual gyro value, this depends on scale being set 00734 gy = (float)gyroCount[1]*gRes - gyroBias[1]; 00735 gz = (float)gyroCount[2]*gRes - gyroBias[2]; 00736 00737 mpu9250.readMagData(magCount); // Read the x/y/z adc values 00738 // Calculate the magnetometer values in milliGauss 00739 // Include factory calibration per data sheet and user environmental corrections 00740 mx = (float)magCount[0]*mRes*magCalibration[0] - magbias[0]; // get actual magnetometer value, this depends on scale being set 00741 my = (float)magCount[1]*mRes*magCalibration[1] - magbias[1]; 00742 mz = (float)magCount[2]*mRes*magCalibration[2] - magbias[2]; 00743 } 00744 00745 pc.printf("ax, ay, az, delta_t;%f;%f;%f;%f\n\r", ax, ay, az*GRAVITATION + GRAVITATION, deltat); 00746 00747 Now = t.read_us(); 00748 00749 deltat = (float)((Now - lastUpdate)/1000000.0f) ; // set integration time by time elapsed since last filter update 00750 lastUpdate = Now; 00751 00752 sum += deltat; 00753 sumCount++; 00754 00755 00756 mpu9250.velocityUpdate(ax, ay, az); 00757 00758 // Pass gyro rate as rad/s 00759 mpu9250.MadgwickQuaternionUpdate(ax, ay, az, gx*PI/180.0f, gy*PI/180.0f, gz*PI/180.0f, my, mx, mz); 00760 //mpu9250.MahonyQuaternionUpdate(ax, ay, az, gx*PI/180.0f, gy*PI/180.0f, gz*PI/180.0f, my, mx, mz); 00761 00762 // Serial print and/or display at 0.5 s rate independent of data rates 00763 delt_t = t.read_ms() - _count; 00764 00765 //----------------------------------------- 00766 // Update displayed value 00767 if (delt_t > SAMPLE_TIME) { 00768 00769 00770 00771 //pc.printf("vx, vy, vz: %f %f %f\n\r", v_trans[0], v_trans[1], v_trans[2]); 00772 00773 00774 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]); 00775 pitch = -asin(2.0f * (q[1] * q[3] - q[0] * q[2])); 00776 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]); 00777 pitch *= 180.0f / PI; 00778 yaw *= 180.0f / PI; 00779 yaw -= 2.93f; // Declination at 8572 Berg TG: +2° 56' 00780 roll *= 180.0f / PI; 00781 00782 myData.ax = yaw; 00783 myData.ay = pitch; 00784 myData.az = roll; 00785 00786 00787 myled= !myled; 00788 _count = t.read_ms(); 00789 00790 if(_count > 1<<21) { 00791 t.start(); // start the timer over again if ~30 minutes has passed 00792 _count = 0; 00793 deltat= 0; 00794 lastUpdate = t.read_us(); 00795 } 00796 sum = 0; 00797 sumCount = 0; 00798 } 00799 } 00800 00801 00802 void MPU9250::imuSetup() 00803 { 00804 //Set up I2C 00805 i2c.frequency(400000); // use fast (400 kHz) I2C 00806 00807 pc.printf("CPU SystemCoreClock is %d Hz\r\n", SystemCoreClock); 00808 00809 t.start(); 00810 // lcd.setBrightness(0.05); 00811 00812 00813 // Read the WHO_AM_I register, this is a good test of communication 00814 uint8_t whoami = mpu9250.readByte(MPU9250_ADDRESS, WHO_AM_I_MPU9250); // Read WHO_AM_I register for MPU-9250 00815 pc.printf("I AM 0x%x\n\r", whoami); 00816 pc.printf("I SHOULD BE 0x71\n\r"); 00817 00818 if (whoami == 0x71) { // WHO_AM_I should always be 0x68 00819 pc.printf("MPU9250 WHO_AM_I is 0x%x\n\r", whoami); 00820 pc.printf("MPU9250 is online...\n\r"); 00821 sprintf(buffer, "0x%x", whoami); 00822 wait(1); 00823 00824 mpu9250.resetMPU9250(); // Reset registers to default in preparation for device calibration 00825 mpu9250.MPU9250SelfTest(SelfTest); // Start by performing self test and reporting values 00826 pc.printf("x-axis self test: acceleration trim within : %f % of factory value\n\r", SelfTest[0]); 00827 pc.printf("y-axis self test: acceleration trim within : %f % of factory value\n\r", SelfTest[1]); 00828 pc.printf("z-axis self test: acceleration trim within : %f % of factory value\n\r", SelfTest[2]); 00829 pc.printf("x-axis self test: gyration trim within : %f % of factory value\n\r", SelfTest[3]); 00830 pc.printf("y-axis self test: gyration trim within : %f % of factory value\n\r", SelfTest[4]); 00831 pc.printf("z-axis self test: gyration trim within : %f % of factory value\n\r", SelfTest[5]); 00832 mpu9250.calibrateMPU9250(gyroBias, accelBias); // Calibrate gyro and accelerometers, load biases in bias registers 00833 pc.printf("x gyro bias = %f\n\r", gyroBias[0]); 00834 pc.printf("y gyro bias = %f\n\r", gyroBias[1]); 00835 pc.printf("z gyro bias = %f\n\r", gyroBias[2]); 00836 pc.printf("x accel bias = %f\n\r", accelBias[0]); 00837 pc.printf("y accel bias = %f\n\r", accelBias[1]); 00838 pc.printf("z accel bias = %f\n\r", accelBias[2]); 00839 wait(2); 00840 mpu9250.initMPU9250(); 00841 pc.printf("MPU9250 initialized for active data mode....\n\r"); // Initialize device for active mode read of acclerometer, gyroscope, and temperature 00842 mpu9250.initAK8963(magCalibration); 00843 pc.printf("AK8963 initialized for active data mode....\n\r"); // Initialize device for active mode read of magnetometer 00844 pc.printf("Accelerometer full-scale range = %f g\n\r", 2.0f*(float)(1<<Ascale)); 00845 pc.printf("Gyroscope full-scale range = %f deg/s\n\r", 250.0f*(float)(1<<Gscale)); 00846 if(Mscale == 0) pc.printf("Magnetometer resolution = 14 bits\n\r"); 00847 if(Mscale == 1) pc.printf("Magnetometer resolution = 16 bits\n\r"); 00848 if(Mmode == 2) pc.printf("Magnetometer ODR = 8 Hz\n\r"); 00849 if(Mmode == 6) pc.printf("Magnetometer ODR = 100 Hz\n\r"); 00850 wait(1); 00851 } else { 00852 pc.printf("Could not connect to MPU9250: \n\r"); 00853 pc.printf("%#x \n", whoami); 00854 sprintf(buffer, "WHO_AM_I 0x%x", whoami); 00855 00856 while(1) { 00857 // Loop forever if communication doesn't happen 00858 pc.printf("no IMU detected (verify if it's plugged in)\n\r"); 00859 } 00860 } 00861 00862 mpu9250.getAres(); // Get accelerometer sensitivity 00863 mpu9250.getGres(); // Get gyro sensitivity 00864 mpu9250.getMres(); // Get magnetometer sensitivity 00865 pc.printf("Accelerometer sensitivity is %f LSB/g \n\r", 1.0f/aRes); 00866 pc.printf("Gyroscope sensitivity is %f LSB/deg/s \n\r", 1.0f/gRes); 00867 pc.printf("Magnetometer sensitivity is %f LSB/G \n\r", 1.0f/mRes); 00868 magbias[0] = +470.; // User environmental x-axis correction in milliGauss, should be automatically calculated 00869 magbias[1] = +120.; // User environmental x-axis correction in milliGauss 00870 magbias[2] = +125.; // User environmental x-axis correction in milliGauss 00871 } 00872 00873 accData_t MPU9250::getVelocityFromIMU(){ 00874 readIMU(); 00875 00876 return myData; 00877 }
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