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MPU9250.cpp
00001 #include "MPU9250.h" 00002 00003 00004 uint8_t Ascale = AFS_2G; // AFS_2G, AFS_4G, AFS_8G, AFS_16G 00005 uint8_t Gscale = GFS_250DPS; // GFS_250DPS, GFS_500DPS, GFS_1000DPS, GFS_2000DPS 00006 uint8_t Mscale = MFS_16BITS; // MFS_14BITS or MFS_16BITS, 14-bit or 16-bit magnetometer resolution 00007 uint8_t Mmode = 0x06; // Either 8 Hz 0x02) or 100 Hz (0x06) magnetometer data ODR 00008 float aRes, gRes, mRes; // scale resolutions per LSB for the sensors 00009 00010 //Set up I2C, (SDA,SCL) 00011 I2C i2c(PB_9, PB_8); 00012 00013 DigitalOut myled(LED1); 00014 00015 // Pin definitions 00016 int intPin = 12; // These can be changed, 2 and 3 are the Arduinos ext int pins 00017 00018 int16_t accelCount[3]; // Stores the 16-bit signed accelerometer sensor output 00019 int16_t gyroCount[3]; // Stores the 16-bit signed gyro sensor output 00020 int16_t magCount[3]; // Stores the 16-bit signed magnetometer sensor output 00021 float magCalibration[3] = {0, 0, 0}, magbias[3] = {0, 0, 0}; // Factory mag calibration and mag bias 00022 float gyroBias[3] = {0, 0, 0}, accelBias[3] = {0, 0, 0}; // Bias corrections for gyro and accelerometer 00023 float ax, ay, az, gx, gy, gz, mx, my, mz; // variables to hold latest sensor data values 00024 int16_t tempCount; // Stores the real internal chip temperature in degrees Celsius 00025 float temperature; 00026 float SelfTest[6]; 00027 00028 int delt_t = 0; // used to control display output rate 00029 int _count = 0; // used to control display output rate 00030 00031 // parameters for 6 DoF sensor fusion calculations 00032 float PI = 3.14159265358979323846f; 00033 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 00034 float beta = sqrt(3.0f / 4.0f) * GyroMeasError; // compute beta 00035 float GyroMeasDrift = PI * (1.0f / 180.0f); // gyroscope measurement drift in rad/s/s (start at 0.0 deg/s/s) 00036 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 00037 #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 00038 #define Ki 0.0f 00039 00040 float pitch, yaw, roll; 00041 float vx, vy, vz; 00042 float deltat = 0.0f; // integration interval for both filter schemes 00043 int lastUpdate = 0, firstUpdate = 0, Now = 0; // used to calculate integration interval // used to calculate integration interval 00044 float q[4] = {1.0f, 0.0f, 0.0f, 0.0f}; // vector to hold quaternion 00045 float v_trans[3] = {0.0f, 0.0f, 0.0f}; // vector to hold translative velocities 00046 float a_old[3] = {0.00f, 0.00f, 0.00f}; 00047 float eInt[3] = {0.0f, 0.0f, 0.0f}; // vector to hold integral error for Mahony method 00048 00049 accData_t myData; 00050 Timer t; 00051 00052 #define SAMPLE_TIME 100 00053 00054 #define STEP_NUMBER 5 00055 float sum = 0; 00056 uint32_t sumCount = 0; 00057 char buffer[14]; 00058 float ax_sum = 0; 00059 static float vx_buffer[STEP_NUMBER]; 00060 static int8_t stepCounter = 0; 00061 00062 00063 // MPU9250-Constructor 00064 MPU9250::MPU9250(Serial* serialPtr) 00065 { 00066 pc = serialPtr; 00067 imuSetup(); 00068 vx_old = 0; 00069 } 00070 00071 00072 00073 //=================================================================================================================== 00074 //====== Set of useful function to access acceleratio, gyroscope, and temperature data 00075 //=================================================================================================================== 00076 00077 void MPU9250::writeByte(uint8_t address, uint8_t subAddress, uint8_t data) 00078 { 00079 char data_write[2]; 00080 data_write[0] = subAddress; 00081 data_write[1] = data; 00082 i2c.write(address, data_write, 2, 0); 00083 } 00084 00085 char MPU9250::readByte(uint8_t address, uint8_t subAddress) 00086 { 00087 char data[1]; // `data` will store the register data 00088 char data_write[1]; 00089 data_write[0] = subAddress; 00090 i2c.write(address, data_write, 1, 1); // no stop 00091 i2c.read(address, data, 1, 0); 00092 return data[0]; 00093 } 00094 00095 void MPU9250::readBytes(uint8_t address, uint8_t subAddress, uint8_t count, uint8_t * dest) 00096 { 00097 char data[14]; 00098 char data_write[1]; 00099 data_write[0] = subAddress; 00100 i2c.write(address, data_write, 1, 1); // no stop 00101 i2c.read(address, data, count, 0); 00102 for(int ii = 0; ii < count; ii++) { 00103 dest[ii] = data[ii]; 00104 } 00105 } 00106 00107 00108 void MPU9250::getMres() 00109 { 00110 switch (Mscale) { 00111 // Possible magnetometer scales (and their register bit settings) are: 00112 // 14 bit resolution (0) and 16 bit resolution (1) 00113 case MFS_14BITS: 00114 mRes = 10.0*4219.0/8190.0; // Proper scale to return milliGauss 00115 break; 00116 case MFS_16BITS: 00117 mRes = 10.0*4219.0/32760.0; // Proper scale to return milliGauss 00118 break; 00119 } 00120 } 00121 00122 00123 void MPU9250::getGres() 00124 { 00125 switch (Gscale) { 00126 // Possible gyro scales (and their register bit settings) are: 00127 // 250 DPS (00), 500 DPS (01), 1000 DPS (10), and 2000 DPS (11). 00128 // Here's a bit of an algorith to calculate DPS/(ADC tick) based on that 2-bit value: 00129 case GFS_250DPS: 00130 gRes = 250.0/32768.0; 00131 break; 00132 case GFS_500DPS: 00133 gRes = 500.0/32768.0; 00134 break; 00135 case GFS_1000DPS: 00136 gRes = 1000.0/32768.0; 00137 break; 00138 case GFS_2000DPS: 00139 gRes = 2000.0/32768.0; 00140 break; 00141 } 00142 } 00143 00144 00145 void MPU9250::getAres() 00146 { 00147 switch (Ascale) { 00148 // Possible accelerometer scales (and their register bit settings) are: 00149 // 2 Gs (00), 4 Gs (01), 8 Gs (10), and 16 Gs (11). 00150 // Here's a bit of an algorith to calculate DPS/(ADC tick) based on that 2-bit value: 00151 case AFS_2G: 00152 aRes = 2.0/32768.0; 00153 break; 00154 case AFS_4G: 00155 aRes = 4.0/32768.0; 00156 break; 00157 case AFS_8G: 00158 aRes = 8.0/32768.0; 00159 break; 00160 case AFS_16G: 00161 aRes = 16.0/32768.0; 00162 break; 00163 } 00164 } 00165 00166 00167 void MPU9250::readAccelData(int16_t * destination) 00168 { 00169 uint8_t rawData[6]; // x/y/z accel register data stored here 00170 readBytes(MPU9250_ADDRESS, ACCEL_XOUT_H, 6, &rawData[0]); // Read the six raw data registers 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::readGyroData(int16_t * destination) 00177 { 00178 uint8_t rawData[6]; // x/y/z gyro register data stored here 00179 readBytes(MPU9250_ADDRESS, GYRO_XOUT_H, 6, &rawData[0]); // Read the six raw data registers sequentially into data array 00180 destination[0] = (int16_t)(((int16_t)rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value 00181 destination[1] = (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ; 00182 destination[2] = (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ; 00183 } 00184 00185 void MPU9250::readMagData(int16_t * destination) 00186 { 00187 uint8_t rawData[7]; // x/y/z gyro register data, ST2 register stored here, must read ST2 at end of data acquisition 00188 if(readByte(AK8963_ADDRESS, AK8963_ST1) & 0x01) { // wait for magnetometer data ready bit to be set 00189 readBytes(AK8963_ADDRESS, AK8963_XOUT_L, 7, &rawData[0]); // Read the six raw data and ST2 registers sequentially into data array 00190 uint8_t c = rawData[6]; // End data read by reading ST2 register 00191 if(!(c & 0x08)) { // Check if magnetic sensor overflow set, if not then report data 00192 destination[0] = (int16_t)(((int16_t)rawData[1] << 8) | rawData[0]); // Turn the MSB and LSB into a signed 16-bit value 00193 destination[1] = (int16_t)(((int16_t)rawData[3] << 8) | rawData[2]) ; // Data stored as little Endian 00194 destination[2] = (int16_t)(((int16_t)rawData[5] << 8) | rawData[4]) ; 00195 } 00196 } 00197 } 00198 00199 int16_t MPU9250::readTempData() 00200 { 00201 uint8_t rawData[2]; // x/y/z gyro register data stored here 00202 readBytes(MPU9250_ADDRESS, TEMP_OUT_H, 2, &rawData[0]); // Read the two raw data registers sequentially into data array 00203 return (int16_t)(((int16_t)rawData[0]) << 8 | rawData[1]) ; // Turn the MSB and LSB into a 16-bit value 00204 } 00205 00206 00207 void MPU9250::resetMPU9250() 00208 { 00209 // reset device 00210 writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x80); // Write a one to bit 7 reset bit; toggle reset device 00211 wait(0.1); 00212 } 00213 00214 void MPU9250::initAK8963(float * destination) 00215 { 00216 // First extract the factory calibration for each magnetometer axis 00217 uint8_t rawData[3]; // x/y/z gyro calibration data stored here 00218 writeByte(AK8963_ADDRESS, AK8963_CNTL, 0x00); // Power down magnetometer 00219 wait(0.01); 00220 writeByte(AK8963_ADDRESS, AK8963_CNTL, 0x0F); // Enter Fuse ROM access mode 00221 wait(0.01); 00222 readBytes(AK8963_ADDRESS, AK8963_ASAX, 3, &rawData[0]); // Read the x-, y-, and z-axis calibration values 00223 destination[0] = (float)(rawData[0] - 128)/256.0f + 1.0f; // Return x-axis sensitivity adjustment values, etc. 00224 destination[1] = (float)(rawData[1] - 128)/256.0f + 1.0f; 00225 destination[2] = (float)(rawData[2] - 128)/256.0f + 1.0f; 00226 writeByte(AK8963_ADDRESS, AK8963_CNTL, 0x00); // Power down magnetometer 00227 wait(0.01); 00228 // Configure the magnetometer for continuous read and highest resolution 00229 // set Mscale bit 4 to 1 (0) to enable 16 (14) bit resolution in CNTL register, 00230 // and enable continuous mode data acquisition Mmode (bits [3:0]), 0010 for 8 Hz and 0110 for 100 Hz sample rates 00231 writeByte(AK8963_ADDRESS, AK8963_CNTL, Mscale << 4 | Mmode); // Set magnetometer data resolution and sample ODR 00232 wait(0.01); 00233 } 00234 00235 00236 void MPU9250::initMPU9250() 00237 { 00238 // Initialize MPU9250 device 00239 // wake up device 00240 writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x00); // Clear sleep mode bit (6), enable all sensors 00241 wait(0.1); // Delay 100 ms for PLL to get established on x-axis gyro; should check for PLL ready interrupt 00242 00243 // get stable time source 00244 writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x01); // Set clock source to be PLL with x-axis gyroscope reference, bits 2:0 = 001 00245 00246 // Configure Gyro and Accelerometer 00247 // Disable FSYNC and set accelerometer and gyro bandwidth to 44 and 42 Hz, respectively; 00248 // DLPF_CFG = bits 2:0 = 010; this sets the sample rate at 1 kHz for both 00249 // Maximum delay is 4.9 ms which is just over a 200 Hz maximum rate 00250 writeByte(MPU9250_ADDRESS, CONFIG, 0x03); 00251 00252 // Set sample rate = gyroscope output rate/(1 + SMPLRT_DIV) 00253 writeByte(MPU9250_ADDRESS, SMPLRT_DIV, 0x04); // Use a 200 Hz rate; the same rate set in CONFIG above 00254 00255 // Set gyroscope full scale range 00256 // Range selects FS_SEL and AFS_SEL are 0 - 3, so 2-bit values are left-shifted into positions 4:3 00257 uint8_t c = readByte(MPU9250_ADDRESS, GYRO_CONFIG); 00258 writeByte(MPU9250_ADDRESS, GYRO_CONFIG, c & ~0xE0); // Clear self-test bits [7:5] 00259 writeByte(MPU9250_ADDRESS, GYRO_CONFIG, c & ~0x18); // Clear AFS bits [4:3] 00260 writeByte(MPU9250_ADDRESS, GYRO_CONFIG, c | Gscale << 3); // Set full scale range for the gyro 00261 00262 // Set accelerometer configuration 00263 c = readByte(MPU9250_ADDRESS, ACCEL_CONFIG); 00264 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, c & ~0xE0); // Clear self-test bits [7:5] 00265 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, c & ~0x18); // Clear AFS bits [4:3] 00266 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, c | Ascale << 3); // Set full scale range for the accelerometer 00267 00268 // Set accelerometer sample rate configuration 00269 // It is possible to get a 4 kHz sample rate from the accelerometer by choosing 1 for 00270 // accel_fchoice_b bit [3]; in this case the bandwidth is 1.13 kHz 00271 c = readByte(MPU9250_ADDRESS, ACCEL_CONFIG2); 00272 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG2, c & ~0x0F); // Clear accel_fchoice_b (bit 3) and A_DLPFG (bits [2:0]) 00273 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG2, c | 0x03); // Set accelerometer rate to 1 kHz and bandwidth to 41 Hz 00274 00275 // The accelerometer, gyro, and thermometer are set to 1 kHz sample rates, 00276 // but all these rates are further reduced by a factor of 5 to 200 Hz because of the SMPLRT_DIV setting 00277 00278 // Configure Interrupts and Bypass Enable 00279 // Set interrupt pin active high, push-pull, and clear on read of INT_STATUS, enable I2C_BYPASS_EN so additional chips 00280 // can join the I2C bus and all can be controlled by the Arduino as master 00281 writeByte(MPU9250_ADDRESS, INT_PIN_CFG, 0x22); 00282 writeByte(MPU9250_ADDRESS, INT_ENABLE, 0x01); // Enable data ready (bit 0) interrupt 00283 } 00284 00285 // Function which accumulates gyro and accelerometer data after device initialization. It calculates the average 00286 // of the at-rest readings and then loads the resulting offsets into accelerometer and gyro bias registers. 00287 void MPU9250::calibrateMPU9250(float * dest1, float * dest2) 00288 { 00289 uint8_t data[12]; // data array to hold accelerometer and gyro x, y, z, data 00290 uint16_t ii, packet_count, fifo_count; 00291 int32_t gyro_bias[3] = {0, 0, 0}, accel_bias[3] = {0, 0, 0}; 00292 00293 // reset device, reset all registers, clear gyro and accelerometer bias registers 00294 writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x80); // Write a one to bit 7 reset bit; toggle reset device 00295 wait(0.1); 00296 00297 // get stable time source 00298 // Set clock source to be PLL with x-axis gyroscope reference, bits 2:0 = 001 00299 writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x01); 00300 writeByte(MPU9250_ADDRESS, PWR_MGMT_2, 0x00); 00301 wait(0.2); 00302 00303 // Configure device for bias calculation 00304 writeByte(MPU9250_ADDRESS, INT_ENABLE, 0x00); // Disable all interrupts 00305 writeByte(MPU9250_ADDRESS, FIFO_EN, 0x00); // Disable FIFO 00306 writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x00); // Turn on internal clock source 00307 writeByte(MPU9250_ADDRESS, I2C_MST_CTRL, 0x00); // Disable I2C master 00308 writeByte(MPU9250_ADDRESS, USER_CTRL, 0x00); // Disable FIFO and I2C master modes 00309 writeByte(MPU9250_ADDRESS, USER_CTRL, 0x0C); // Reset FIFO and DMP 00310 wait(0.015); 00311 00312 // Configure MPU9250 gyro and accelerometer for bias calculation 00313 writeByte(MPU9250_ADDRESS, CONFIG, 0x01); // Set low-pass filter to 188 Hz 00314 writeByte(MPU9250_ADDRESS, SMPLRT_DIV, 0x00); // Set sample rate to 1 kHz 00315 writeByte(MPU9250_ADDRESS, GYRO_CONFIG, 0x00); // Set gyro full-scale to 250 degrees per second, maximum sensitivity 00316 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, 0x00); // Set accelerometer full-scale to 2 g, maximum sensitivity 00317 00318 uint16_t gyrosensitivity = 131; // = 131 LSB/degrees/sec 00319 uint16_t accelsensitivity = 16384; // = 16384 LSB/g 00320 00321 // Configure FIFO to capture accelerometer and gyro data for bias calculation 00322 writeByte(MPU9250_ADDRESS, USER_CTRL, 0x40); // Enable FIFO 00323 writeByte(MPU9250_ADDRESS, FIFO_EN, 0x78); // Enable gyro and accelerometer sensors for FIFO (max size 512 bytes in MPU-9250) 00324 wait(0.04); // accumulate 40 samples in 80 milliseconds = 480 bytes 00325 00326 // At end of sample accumulation, turn off FIFO sensor read 00327 writeByte(MPU9250_ADDRESS, FIFO_EN, 0x00); // Disable gyro and accelerometer sensors for FIFO 00328 readBytes(MPU9250_ADDRESS, FIFO_COUNTH, 2, &data[0]); // read FIFO sample count 00329 fifo_count = ((uint16_t)data[0] << 8) | data[1]; 00330 packet_count = fifo_count/12;// How many sets of full gyro and accelerometer data for averaging 00331 00332 for (ii = 0; ii < packet_count; ii++) { 00333 int16_t accel_temp[3] = {0, 0, 0}, gyro_temp[3] = {0, 0, 0}; 00334 readBytes(MPU9250_ADDRESS, FIFO_R_W, 12, &data[0]); // read data for averaging 00335 accel_temp[0] = (int16_t) (((int16_t)data[0] << 8) | data[1] ) ; // Form signed 16-bit integer for each sample in FIFO 00336 accel_temp[1] = (int16_t) (((int16_t)data[2] << 8) | data[3] ) ; 00337 accel_temp[2] = (int16_t) (((int16_t)data[4] << 8) | data[5] ) ; 00338 gyro_temp[0] = (int16_t) (((int16_t)data[6] << 8) | data[7] ) ; 00339 gyro_temp[1] = (int16_t) (((int16_t)data[8] << 8) | data[9] ) ; 00340 gyro_temp[2] = (int16_t) (((int16_t)data[10] << 8) | data[11]) ; 00341 00342 accel_bias[0] += (int32_t) accel_temp[0]; // Sum individual signed 16-bit biases to get accumulated signed 32-bit biases 00343 accel_bias[1] += (int32_t) accel_temp[1]; 00344 accel_bias[2] += (int32_t) accel_temp[2]; 00345 gyro_bias[0] += (int32_t) gyro_temp[0]; 00346 gyro_bias[1] += (int32_t) gyro_temp[1]; 00347 gyro_bias[2] += (int32_t) gyro_temp[2]; 00348 00349 } 00350 accel_bias[0] /= (int32_t) packet_count; // Normalize sums to get average count biases 00351 accel_bias[1] /= (int32_t) packet_count; 00352 accel_bias[2] /= (int32_t) packet_count; 00353 gyro_bias[0] /= (int32_t) packet_count; 00354 gyro_bias[1] /= (int32_t) packet_count; 00355 gyro_bias[2] /= (int32_t) packet_count; 00356 00357 if(accel_bias[2] > 0L) { 00358 accel_bias[2] -= (int32_t) accelsensitivity; // Remove gravity from the z-axis accelerometer bias calculation 00359 } else { 00360 accel_bias[2] += (int32_t) accelsensitivity; 00361 } 00362 00363 // Construct the gyro biases for push to the hardware gyro bias registers, which are reset to zero upon device startup 00364 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 00365 data[1] = (-gyro_bias[0]/4) & 0xFF; // Biases are additive, so change sign on calculated average gyro biases 00366 data[2] = (-gyro_bias[1]/4 >> 8) & 0xFF; 00367 data[3] = (-gyro_bias[1]/4) & 0xFF; 00368 data[4] = (-gyro_bias[2]/4 >> 8) & 0xFF; 00369 data[5] = (-gyro_bias[2]/4) & 0xFF; 00370 00371 /// Push gyro biases to hardware registers 00372 /* writeByte(MPU9250_ADDRESS, XG_OFFSET_H, data[0]); 00373 writeByte(MPU9250_ADDRESS, XG_OFFSET_L, data[1]); 00374 writeByte(MPU9250_ADDRESS, YG_OFFSET_H, data[2]); 00375 writeByte(MPU9250_ADDRESS, YG_OFFSET_L, data[3]); 00376 writeByte(MPU9250_ADDRESS, ZG_OFFSET_H, data[4]); 00377 writeByte(MPU9250_ADDRESS, ZG_OFFSET_L, data[5]); 00378 */ 00379 dest1[0] = (float) gyro_bias[0]/(float) gyrosensitivity; // construct gyro bias in deg/s for later manual subtraction 00380 dest1[1] = (float) gyro_bias[1]/(float) gyrosensitivity; 00381 dest1[2] = (float) gyro_bias[2]/(float) gyrosensitivity; 00382 00383 // Construct the accelerometer biases for push to the hardware accelerometer bias registers. These registers contain 00384 // factory trim values which must be added to the calculated accelerometer biases; on boot up these registers will hold 00385 // non-zero values. In addition, bit 0 of the lower byte must be preserved since it is used for temperature 00386 // compensation calculations. Accelerometer bias registers expect bias input as 2048 LSB per g, so that 00387 // the accelerometer biases calculated above must be divided by 8. 00388 00389 int32_t accel_bias_reg[3] = {0, 0, 0}; // A place to hold the factory accelerometer trim biases 00390 readBytes(MPU9250_ADDRESS, XA_OFFSET_H, 2, &data[0]); // Read factory accelerometer trim values 00391 accel_bias_reg[0] = (int16_t) ((int16_t)data[0] << 8) | data[1]; 00392 readBytes(MPU9250_ADDRESS, YA_OFFSET_H, 2, &data[0]); 00393 accel_bias_reg[1] = (int16_t) ((int16_t)data[0] << 8) | data[1]; 00394 readBytes(MPU9250_ADDRESS, ZA_OFFSET_H, 2, &data[0]); 00395 accel_bias_reg[2] = (int16_t) ((int16_t)data[0] << 8) | data[1]; 00396 00397 uint32_t mask = 1uL; // Define mask for temperature compensation bit 0 of lower byte of accelerometer bias registers 00398 uint8_t mask_bit[3] = {0, 0, 0}; // Define array to hold mask bit for each accelerometer bias axis 00399 00400 for(ii = 0; ii < 3; ii++) { 00401 if(accel_bias_reg[ii] & mask) mask_bit[ii] = 0x01; // If temperature compensation bit is set, record that fact in mask_bit 00402 } 00403 00404 // Construct total accelerometer bias, including calculated average accelerometer bias from above 00405 accel_bias_reg[0] -= (accel_bias[0]/8); // Subtract calculated averaged accelerometer bias scaled to 2048 LSB/g (16 g full scale) 00406 accel_bias_reg[1] -= (accel_bias[1]/8); 00407 accel_bias_reg[2] -= (accel_bias[2]/8); 00408 00409 data[0] = (accel_bias_reg[0] >> 8) & 0xFF; 00410 data[1] = (accel_bias_reg[0]) & 0xFF; 00411 data[1] = data[1] | mask_bit[0]; // preserve temperature compensation bit when writing back to accelerometer bias registers 00412 data[2] = (accel_bias_reg[1] >> 8) & 0xFF; 00413 data[3] = (accel_bias_reg[1]) & 0xFF; 00414 data[3] = data[3] | mask_bit[1]; // preserve temperature compensation bit when writing back to accelerometer bias registers 00415 data[4] = (accel_bias_reg[2] >> 8) & 0xFF; 00416 data[5] = (accel_bias_reg[2]) & 0xFF; 00417 data[5] = data[5] | mask_bit[2]; // preserve temperature compensation bit when writing back to accelerometer bias registers 00418 00419 // Apparently this is not working for the acceleration biases in the MPU-9250 00420 // Are we handling the temperature correction bit properly? 00421 // Push accelerometer biases to hardware registers 00422 /* writeByte(MPU9250_ADDRESS, XA_OFFSET_H, data[0]); 00423 writeByte(MPU9250_ADDRESS, XA_OFFSET_L, data[1]); 00424 writeByte(MPU9250_ADDRESS, YA_OFFSET_H, data[2]); 00425 writeByte(MPU9250_ADDRESS, YA_OFFSET_L, data[3]); 00426 writeByte(MPU9250_ADDRESS, ZA_OFFSET_H, data[4]); 00427 writeByte(MPU9250_ADDRESS, ZA_OFFSET_L, data[5]); 00428 */ 00429 // Output scaled accelerometer biases for manual subtraction in the main program 00430 dest2[0] = (float)accel_bias[0]/(float)accelsensitivity; 00431 dest2[1] = (float)accel_bias[1]/(float)accelsensitivity; 00432 dest2[2] = (float)accel_bias[2]/(float)accelsensitivity; 00433 } 00434 00435 00436 // Accelerometer and gyroscope self test; check calibration wrt factory settings 00437 void MPU9250::MPU9250SelfTest(float * destination) // Should return percent deviation from factory trim values, +/- 14 or less deviation is a pass 00438 { 00439 uint8_t rawData[6] = {0, 0, 0, 0, 0, 0}; 00440 uint8_t selfTest[6]; 00441 int16_t gAvg[3], aAvg[3], aSTAvg[3], gSTAvg[3]; 00442 float factoryTrim[6]; 00443 uint8_t FS = 0; 00444 00445 writeByte(MPU9250_ADDRESS, SMPLRT_DIV, 0x00); // Set gyro sample rate to 1 kHz 00446 writeByte(MPU9250_ADDRESS, CONFIG, 0x02); // Set gyro sample rate to 1 kHz and DLPF to 92 Hz 00447 writeByte(MPU9250_ADDRESS, GYRO_CONFIG, 1<<FS); // Set full scale range for the gyro to 250 dps 00448 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG2, 0x02); // Set accelerometer rate to 1 kHz and bandwidth to 92 Hz 00449 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, 1<<FS); // Set full scale range for the accelerometer to 2 g 00450 00451 for( int ii = 0; ii < 200; ii++) { // get average current values of gyro and acclerometer 00452 00453 readBytes(MPU9250_ADDRESS, ACCEL_XOUT_H, 6, &rawData[0]); // Read the six raw data registers into data array 00454 aAvg[0] += (int16_t)(((int16_t)rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value 00455 aAvg[1] += (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ; 00456 aAvg[2] += (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ; 00457 00458 readBytes(MPU9250_ADDRESS, GYRO_XOUT_H, 6, &rawData[0]); // Read the six raw data registers sequentially into data array 00459 gAvg[0] += (int16_t)(((int16_t)rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value 00460 gAvg[1] += (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ; 00461 gAvg[2] += (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ; 00462 } 00463 00464 for (int ii =0; ii < 3; ii++) { // Get average of 200 values and store as average current readings 00465 aAvg[ii] /= 200; 00466 gAvg[ii] /= 200; 00467 } 00468 00469 // Configure the accelerometer for self-test 00470 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, 0xE0); // Enable self test on all three axes and set accelerometer range to +/- 2 g 00471 writeByte(MPU9250_ADDRESS, GYRO_CONFIG, 0xE0); // Enable self test on all three axes and set gyro range to +/- 250 degrees/s 00472 wait(0.025); // Delay a while to let the device stabilize 00473 00474 for( int ii = 0; ii < 200; ii++) { // get average self-test values of gyro and acclerometer 00475 00476 readBytes(MPU9250_ADDRESS, ACCEL_XOUT_H, 6, &rawData[0]); // Read the six raw data registers into data array 00477 aSTAvg[0] += (int16_t)(((int16_t)rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value 00478 aSTAvg[1] += (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ; 00479 aSTAvg[2] += (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ; 00480 00481 readBytes(MPU9250_ADDRESS, GYRO_XOUT_H, 6, &rawData[0]); // Read the six raw data registers sequentially into data array 00482 gSTAvg[0] += (int16_t)(((int16_t)rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value 00483 gSTAvg[1] += (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ; 00484 gSTAvg[2] += (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ; 00485 } 00486 00487 for (int ii =0; ii < 3; ii++) { // Get average of 200 values and store as average self-test readings 00488 aSTAvg[ii] /= 200; 00489 gSTAvg[ii] /= 200; 00490 } 00491 00492 // Configure the gyro and accelerometer for normal operation 00493 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, 0x00); 00494 writeByte(MPU9250_ADDRESS, GYRO_CONFIG, 0x00); 00495 wait(0.025); // Delay a while to let the device stabilize 00496 00497 // Retrieve accelerometer and gyro factory Self-Test Code from USR_Reg 00498 selfTest[0] = readByte(MPU9250_ADDRESS, SELF_TEST_X_ACCEL); // X-axis accel self-test results 00499 selfTest[1] = readByte(MPU9250_ADDRESS, SELF_TEST_Y_ACCEL); // Y-axis accel self-test results 00500 selfTest[2] = readByte(MPU9250_ADDRESS, SELF_TEST_Z_ACCEL); // Z-axis accel self-test results 00501 selfTest[3] = readByte(MPU9250_ADDRESS, SELF_TEST_X_GYRO); // X-axis gyro self-test results 00502 selfTest[4] = readByte(MPU9250_ADDRESS, SELF_TEST_Y_GYRO); // Y-axis gyro self-test results 00503 selfTest[5] = readByte(MPU9250_ADDRESS, SELF_TEST_Z_GYRO); // Z-axis gyro self-test results 00504 00505 // Retrieve factory self-test value from self-test code reads 00506 factoryTrim[0] = (float)(2620/1<<FS)*(pow( 1.01, ((float)selfTest[0] - 1.0) )); // FT[Xa] factory trim calculation 00507 factoryTrim[1] = (float)(2620/1<<FS)*(pow( 1.01, ((float)selfTest[1] - 1.0) )); // FT[Ya] factory trim calculation 00508 factoryTrim[2] = (float)(2620/1<<FS)*(pow( 1.01, ((float)selfTest[2] - 1.0) )); // FT[Za] factory trim calculation 00509 factoryTrim[3] = (float)(2620/1<<FS)*(pow( 1.01, ((float)selfTest[3] - 1.0) )); // FT[Xg] factory trim calculation 00510 factoryTrim[4] = (float)(2620/1<<FS)*(pow( 1.01, ((float)selfTest[4] - 1.0) )); // FT[Yg] factory trim calculation 00511 factoryTrim[5] = (float)(2620/1<<FS)*(pow( 1.01, ((float)selfTest[5] - 1.0) )); // FT[Zg] factory trim calculation 00512 00513 // Report results as a ratio of (STR - FT)/FT; the change from Factory Trim of the Self-Test Response 00514 // To get percent, must multiply by 100 00515 for (int i = 0; i < 3; i++) { 00516 destination[i] = 100.0*((float)(aSTAvg[i] - aAvg[i]))/factoryTrim[i]; // Report percent differences 00517 destination[i+3] = 100.0*((float)(gSTAvg[i] - gAvg[i]))/factoryTrim[i+3]; // Report percent differences 00518 } 00519 00520 } 00521 00522 00523 00524 // Implementation of Sebastian Madgwick's "...efficient orientation filter for... inertial/magnetic sensor arrays" 00525 // (see http://www.x-io.co.uk/category/open-source/ for examples and more details) 00526 // which fuses acceleration, rotation rate, and magnetic moments to produce a quaternion-based estimate of absolute 00527 // device orientation -- which can be converted to yaw, pitch, and roll. Useful for stabilizing quadcopters, etc. 00528 // The performance of the orientation filter is at least as good as conventional Kalman-based filtering algorithms 00529 // but is much less computationally intensive---it can be performed on a 3.3 V Pro Mini operating at 8 MHz! 00530 void MPU9250::MadgwickQuaternionUpdate(float ax, float ay, float az, float gx, float gy, float gz, float mx, float my, float mz) 00531 { 00532 float q1 = q[0], q2 = q[1], q3 = q[2], q4 = q[3]; // short name local variable for readability 00533 float norm; 00534 float hx, hy, _2bx, _2bz; 00535 float s1, s2, s3, s4; 00536 float qDot1, qDot2, qDot3, qDot4; 00537 00538 // Auxiliary variables to avoid repeated arithmetic 00539 float _2q1mx; 00540 float _2q1my; 00541 float _2q1mz; 00542 float _2q2mx; 00543 float _4bx; 00544 float _4bz; 00545 float _2q1 = 2.0f * q1; 00546 float _2q2 = 2.0f * q2; 00547 float _2q3 = 2.0f * q3; 00548 float _2q4 = 2.0f * q4; 00549 float _2q1q3 = 2.0f * q1 * q3; 00550 float _2q3q4 = 2.0f * q3 * q4; 00551 float q1q1 = q1 * q1; 00552 float q1q2 = q1 * q2; 00553 float q1q3 = q1 * q3; 00554 float q1q4 = q1 * q4; 00555 float q2q2 = q2 * q2; 00556 float q2q3 = q2 * q3; 00557 float q2q4 = q2 * q4; 00558 float q3q3 = q3 * q3; 00559 float q3q4 = q3 * q4; 00560 float q4q4 = q4 * q4; 00561 00562 // Normalise accelerometer measurement 00563 norm = sqrt(ax * ax + ay * ay + az * az); 00564 if (norm == 0.0f) return; // handle NaN 00565 norm = 1.0f/norm; 00566 ax *= norm; 00567 ay *= norm; 00568 az *= norm; 00569 00570 // Normalise magnetometer measurement 00571 norm = sqrt(mx * mx + my * my + mz * mz); 00572 if (norm == 0.0f) return; // handle NaN 00573 norm = 1.0f/norm; 00574 mx *= norm; 00575 my *= norm; 00576 mz *= norm; 00577 00578 // Reference direction of Earth's magnetic field 00579 _2q1mx = 2.0f * q1 * mx; 00580 _2q1my = 2.0f * q1 * my; 00581 _2q1mz = 2.0f * q1 * mz; 00582 _2q2mx = 2.0f * q2 * mx; 00583 hx = mx * q1q1 - _2q1my * q4 + _2q1mz * q3 + mx * q2q2 + _2q2 * my * q3 + _2q2 * mz * q4 - mx * q3q3 - mx * q4q4; 00584 hy = _2q1mx * q4 + my * q1q1 - _2q1mz * q2 + _2q2mx * q3 - my * q2q2 + my * q3q3 + _2q3 * mz * q4 - my * q4q4; 00585 _2bx = sqrt(hx * hx + hy * hy); 00586 _2bz = -_2q1mx * q3 + _2q1my * q2 + mz * q1q1 + _2q2mx * q4 - mz * q2q2 + _2q3 * my * q4 - mz * q3q3 + mz * q4q4; 00587 _4bx = 2.0f * _2bx; 00588 _4bz = 2.0f * _2bz; 00589 00590 // Gradient decent algorithm corrective step 00591 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); 00592 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); 00593 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); 00594 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); 00595 norm = sqrt(s1 * s1 + s2 * s2 + s3 * s3 + s4 * s4); // normalise step magnitude 00596 norm = 1.0f/norm; 00597 s1 *= norm; 00598 s2 *= norm; 00599 s3 *= norm; 00600 s4 *= norm; 00601 00602 // Compute rate of change of quaternion 00603 qDot1 = 0.5f * (-q2 * gx - q3 * gy - q4 * gz) - beta * s1; 00604 qDot2 = 0.5f * (q1 * gx + q3 * gz - q4 * gy) - beta * s2; 00605 qDot3 = 0.5f * (q1 * gy - q2 * gz + q4 * gx) - beta * s3; 00606 qDot4 = 0.5f * (q1 * gz + q2 * gy - q3 * gx) - beta * s4; 00607 00608 // Integrate to yield quaternion 00609 q1 += qDot1 * deltat; 00610 q2 += qDot2 * deltat; 00611 q3 += qDot3 * deltat; 00612 q4 += qDot4 * deltat; 00613 norm = sqrt(q1 * q1 + q2 * q2 + q3 * q3 + q4 * q4); // normalise quaternion 00614 norm = 1.0f/norm; 00615 q[0] = q1 * norm; 00616 q[1] = q2 * norm; 00617 q[2] = q3 * norm; 00618 q[3] = q4 * norm; 00619 00620 } 00621 00622 00623 void MPU9250::readIMU() 00624 { 00625 // If intPin goes high, all data registers have new data 00626 if(readByte(MPU9250_ADDRESS, INT_STATUS) & 0x01) { // On interrupt, check if data ready interrupt 00627 00628 readAccelData(accelCount); // Read the x/y/z adc values 00629 // Now we'll calculate the accleration value into actual g's 00630 ax = (float)accelCount[0]*aRes - accelBias[0]; // get actual g value, this depends on scale being set 00631 ay = (float)accelCount[1]*aRes - accelBias[1]; 00632 az = (float)accelCount[2]*aRes - accelBias[2]; 00633 00634 readGyroData(gyroCount); // Read the x/y/z adc values 00635 // Calculate the gyro value into actual degrees per second 00636 gx = (float)gyroCount[0]*gRes - gyroBias[0]; // get actual gyro value, this depends on scale being set 00637 gy = (float)gyroCount[1]*gRes - gyroBias[1]; 00638 gz = (float)gyroCount[2]*gRes - gyroBias[2]; 00639 00640 readMagData(magCount); // Read the x/y/z adc values 00641 // Calculate the magnetometer values in milliGauss 00642 // Include factory calibration per data sheet and user environmental corrections 00643 mx = (float)magCount[0]*mRes*magCalibration[0] - magbias[0]; // get actual magnetometer value, this depends on scale being set 00644 my = (float)magCount[1]*mRes*magCalibration[1] - magbias[1]; 00645 mz = (float)magCount[2]*mRes*magCalibration[2] - magbias[2]; 00646 } 00647 00648 00649 00650 //pc.printf("ax, ay, az, delta_t;%f;%f;%f;%f\n\r", ax, ay, az*GRAVITATION + GRAVITATION, deltat); 00651 00652 Now = t.read_us(); 00653 00654 deltat = (float)((Now - lastUpdate)/1000000.0f) ; // set integration time by time elapsed since last filter update 00655 lastUpdate = Now; 00656 00657 //pc.printf("%f,%f,%f,%f\n\r",ax, ay, az, deltat); 00658 00659 00660 sum += deltat; 00661 sumCount++; 00662 00663 // Pass gyro rate as rad/s 00664 MadgwickQuaternionUpdate(ax, ay, az, gx*PI/180.0f, gy*PI/180.0f, gz*PI/180.0f, my, mx, mz); 00665 //mpu9250.MahonyQuaternionUpdate(ax, ay, az, gx*PI/180.0f, gy*PI/180.0f, gz*PI/180.0f, my, mx, mz); 00666 00667 // Serial print and/or display at 0.5 s rate independent of data rates 00668 delt_t = t.read_ms() - _count; 00669 //pc.printf("Zeit intern: %d\n\r", t.read_ms()); 00670 } 00671 00672 00673 00674 /*//----------------------------------------- 00675 // Update displayed value 00676 if (delt_t > SAMPLE_TIME) { 00677 00678 00679 00680 //pc.printf("vx, vy, vz: %f %f %f\n\r", v_trans[0], v_trans[1], v_trans[2]); 00681 00682 00683 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]); 00684 pitch = -asin(2.0f * (q[1] * q[3] - q[0] * q[2])); 00685 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]); 00686 pitch *= 180.0f / PI; 00687 yaw *= 180.0f / PI; 00688 yaw -= 2.93f; // Declination at 8572 Berg TG: +2° 56' 00689 roll *= 180.0f / PI; 00690 00691 00692 00693 myled= !myled; 00694 _count = t.read_ms(); 00695 00696 if(_count > 1<<21) { 00697 t.start(); // start the timer over again if ~30 minutes has passed 00698 _count = 0; 00699 deltat= 0; 00700 lastUpdate = t.read_us(); 00701 } 00702 sum = 0; 00703 sumCount = 0; 00704 }*/ 00705 00706 00707 00708 void MPU9250::imuSetup() 00709 { 00710 //Set up I2C 00711 i2c.frequency(400000); // use fast (400 kHz) I2C 00712 00713 pc->printf("CPU SystemCoreClock is %d Hz\r\n", SystemCoreClock); 00714 00715 t.start(); 00716 // lcd.setBrightness(0.05); 00717 00718 00719 // Read the WHO_AM_I register, this is a good test of communication 00720 uint8_t whoami = readByte(MPU9250_ADDRESS, WHO_AM_I_MPU9250); // Read WHO_AM_I register for MPU-9250 00721 pc->printf("I AM 0x%x\n\r", whoami); 00722 pc->printf("I SHOULD BE 0x71\n\r"); 00723 00724 if (whoami == 0x71) { // WHO_AM_I should always be 0x68 00725 pc->printf("MPU9250 WHO_AM_I is 0x%x\n\r", whoami); 00726 pc->printf("MPU9250 is online...\n\r"); 00727 sprintf(buffer, "0x%x", whoami); 00728 wait(1); 00729 00730 resetMPU9250(); // Reset registers to default in preparation for device calibration 00731 MPU9250SelfTest(SelfTest); // Start by performing self test and reporting values 00732 pc->printf("x-axis self test: acceleration trim within : %f % of factory value\n\r", SelfTest[0]); 00733 pc->printf("y-axis self test: acceleration trim within : %f % of factory value\n\r", SelfTest[1]); 00734 pc->printf("z-axis self test: acceleration trim within : %f % of factory value\n\r", SelfTest[2]); 00735 pc->printf("x-axis self test: gyration trim within : %f % of factory value\n\r", SelfTest[3]); 00736 pc->printf("y-axis self test: gyration trim within : %f % of factory value\n\r", SelfTest[4]); 00737 pc->printf("z-axis self test: gyration trim within : %f % of factory value\n\r", SelfTest[5]); 00738 calibrateMPU9250(gyroBias, accelBias); // Calibrate gyro and accelerometers, load biases in bias registers 00739 pc->printf("x gyro bias = %f\n\r", gyroBias[0]); 00740 pc->printf("y gyro bias = %f\n\r", gyroBias[1]); 00741 pc->printf("z gyro bias = %f\n\r", gyroBias[2]); 00742 pc->printf("x accel bias = %f\n\r", accelBias[0]); 00743 pc->printf("y accel bias = %f\n\r", accelBias[1]); 00744 pc->printf("z accel bias = %f\n\r", accelBias[2]); 00745 wait(2); 00746 initMPU9250(); 00747 pc->printf("MPU9250 initialized for active data mode....\n\r"); // Initialize device for active mode read of acclerometer, gyroscope, and temperature 00748 initAK8963(magCalibration); 00749 pc->printf("AK8963 initialized for active data mode....\n\r"); // Initialize device for active mode read of magnetometer 00750 pc->printf("Accelerometer full-scale range = %f g\n\r", 2.0f*(float)(1<<Ascale)); 00751 pc->printf("Gyroscope full-scale range = %f deg/s\n\r", 250.0f*(float)(1<<Gscale)); 00752 if(Mscale == 0) pc->printf("Magnetometer resolution = 14 bits\n\r"); 00753 if(Mscale == 1) pc->printf("Magnetometer resolution = 16 bits\n\r"); 00754 if(Mmode == 2) pc->printf("Magnetometer ODR = 8 Hz\n\r"); 00755 if(Mmode == 6) pc->printf("Magnetometer ODR = 100 Hz\n\r"); 00756 wait(1); 00757 } else { 00758 pc->printf("Could not connect to MPU9250: \n\r"); 00759 pc->printf("%#x \n", whoami); 00760 sprintf(buffer, "WHO_AM_I 0x%x", whoami); 00761 00762 while(1) { 00763 // Loop forever if communication doesn't happen 00764 pc->printf("no IMU detected (verify if it's plugged in)\n\r"); 00765 } 00766 } 00767 00768 getAres(); // Get accelerometer sensitivity 00769 getGres(); // Get gyro sensitivity 00770 getMres(); // Get magnetometer sensitivity 00771 pc->printf("Accelerometer sensitivity is %f LSB/g \n\r", 1.0f/aRes); 00772 pc->printf("Gyroscope sensitivity is %f LSB/deg/s \n\r", 1.0f/gRes); 00773 pc->printf("Magnetometer sensitivity is %f LSB/G \n\r", 1.0f/mRes); 00774 magbias[0] = +470.; // User environmental x-axis correction in milliGauss, should be automatically calculated 00775 magbias[1] = +120.; // User environmental x-axis correction in milliGauss 00776 magbias[2] = +125.; // User environmental x-axis correction in milliGauss 00777 } 00778 00779 00780 // N Werte sammeln, Integrale aufsummieren 00781 /*float MPU9250::getMedianAcc(){ 00782 int8_t i; 00783 ax_sum = 0; 00784 for (i=0; i<STEP_NUMBER; i++) { 00785 readIMU(); 00786 //pc.printf("Zeit extern: %d\n\n\r", t.read_ms()); 00787 pc.printf("i=%d: ax=%f\n\r", i, ax); 00788 ax_sum += ax; 00789 } 00790 pc.printf("Summe: %f\n\n\r", ax_sum/steps); 00791 return ax_sum/steps; 00792 }*/ 00793 00794 00795 // BufferArray-Variante 00796 float MPU9250::getVBuffer() 00797 { 00798 // Save the last ax value before readIMU() is executed 00799 float ax_old = ax; 00800 00801 // Save the last vx value 00802 if (stepCounter == 0) { 00803 vx_old = vx_buffer[STEP_NUMBER-1]; 00804 } 00805 else{ 00806 vx_old = vx_buffer[stepCounter - 1]; 00807 } 00808 00809 00810 // Sets new ax value 00811 readIMU(); 00812 00813 00814 // Calculate Integration Step of new and old value 00815 vx_buffer[stepCounter] = vx_old + deltat*0.5f*(ax + ax_old)/GRAVITATION; 00816 00817 int i; 00818 float vx_median = 0; 00819 for (i=0; i<STEP_NUMBER; i++) { 00820 vx_median += vx_buffer[i]; 00821 //pc.printf("%d: %f\n\r", i, vx_buffer[i]); 00822 } 00823 //pc.printf("\n\r"); 00824 //pc.printf("%f,%f,%f,%f\n\r", ax, vx_median/STEP_NUMBER, vx_buffer[stepCounter], deltat); 00825 00826 stepCounter++; 00827 if (stepCounter >= STEP_NUMBER) { 00828 stepCounter = 0; 00829 } 00830 return vx_median/STEP_NUMBER; 00831 }
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