Alan Huchin Herrera / Mbed 2 deprecated Nucleo_MPU_9250_

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Fork of Nucleo_MPU_9250 by Alan Huchin Herrera

MPU9250.cpp@0:89cf0851969b, 2018-06-26 (annotated)

Committer:
AlanHuchin
Date:
Tue Jun 26 18:24:45 2018 +0000
Revision:
0:89cf0851969b
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Who changed what in which revision?

UserRevisionLine numberNew contents of line
AlanHuchin 0:89cf0851969b 1 #include "MPU9250.h"
AlanHuchin 0:89cf0851969b 2
AlanHuchin 0:89cf0851969b 3 // Set initial input parameters
AlanHuchin 0:89cf0851969b 4 enum Ascale {
AlanHuchin 0:89cf0851969b 5 AFS_2G = 0,
AlanHuchin 0:89cf0851969b 6 AFS_4G,
AlanHuchin 0:89cf0851969b 7 AFS_8G,
AlanHuchin 0:89cf0851969b 8 AFS_16G
AlanHuchin 0:89cf0851969b 9 };
AlanHuchin 0:89cf0851969b 10
AlanHuchin 0:89cf0851969b 11 enum Gscale {
AlanHuchin 0:89cf0851969b 12 GFS_250DPS = 0,
AlanHuchin 0:89cf0851969b 13 GFS_500DPS,
AlanHuchin 0:89cf0851969b 14 GFS_1000DPS,
AlanHuchin 0:89cf0851969b 15 GFS_2000DPS
AlanHuchin 0:89cf0851969b 16 };
AlanHuchin 0:89cf0851969b 17
AlanHuchin 0:89cf0851969b 18 enum Mscale {
AlanHuchin 0:89cf0851969b 19 MFS_14BITS = 0, // 0.6 mG per LSB
AlanHuchin 0:89cf0851969b 20 MFS_16BITS // 0.15 mG per LSB
AlanHuchin 0:89cf0851969b 21 };
AlanHuchin 0:89cf0851969b 22
AlanHuchin 0:89cf0851969b 23 float ax,ay,az;
AlanHuchin 0:89cf0851969b 24 float gx,gy,gz;
AlanHuchin 0:89cf0851969b 25 float mx,my,mz;
AlanHuchin 0:89cf0851969b 26 int16_t accelData[3],gyroData[3],tempData;
AlanHuchin 0:89cf0851969b 27 float accelBias[3] = {0, 0, 0}; // Bias corrections for acc
AlanHuchin 0:89cf0851969b 28 float gyroBias[3] = {0, 0, 0};
AlanHuchin 0:89cf0851969b 29 extern float magCalibration[3]= {0, 0, 0};
AlanHuchin 0:89cf0851969b 30 extern float magbias[3]= {0, 0, 0}, magScale[3] = {0, 0, 0};
AlanHuchin 0:89cf0851969b 31 float SelfTest[6];
AlanHuchin 0:89cf0851969b 32
AlanHuchin 0:89cf0851969b 33 int delt_t = 0; // used to control display output rate
AlanHuchin 0:89cf0851969b 34 int count = 0; // used to control display output rate
AlanHuchin 0:89cf0851969b 35
AlanHuchin 0:89cf0851969b 36 // parameters for 6 DoF sensor fusion calculations
AlanHuchin 0:89cf0851969b 37 float PI = 3.14159265358979323846f;
AlanHuchin 0:89cf0851969b 38 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
AlanHuchin 0:89cf0851969b 39 float beta = sqrt(3.0f / 4.0f) * GyroMeasError; // compute beta
AlanHuchin 0:89cf0851969b 40 float GyroMeasDrift = PI * (1.0f / 180.0f); // gyroscope measurement drift in rad/s/s (start at 0.0 deg/s/s)
AlanHuchin 0:89cf0851969b 41 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
AlanHuchin 0:89cf0851969b 42 #define Kp 0.98 // these are the free parameters in the Mahony filter and fusion scheme, Kp for proportional feedback, Ki for integral
AlanHuchin 0:89cf0851969b 43 #define Ki 0.0000001f
AlanHuchin 0:89cf0851969b 44
AlanHuchin 0:89cf0851969b 45 float pitch, yaw, roll;
AlanHuchin 0:89cf0851969b 46 float deltat = 0.0f; // integration interval for both filter schemes
AlanHuchin 0:89cf0851969b 47 int lastUpdate = 0, firstUpdate = 0, Now = 0; // used to calculate integration interval // used to calculate integration interval
AlanHuchin 0:89cf0851969b 48 float q[4] = {1.0f, 0.0f, 0.0f, 0.0f}; // vector to hold quaternion
AlanHuchin 0:89cf0851969b 49 float eInt[3] = {0.0f, 0.0f, 0.0f};
AlanHuchin 0:89cf0851969b 50
AlanHuchin 0:89cf0851969b 51 uint8_t Ascale = AFS_16G; // AFS_2G, AFS_4G, AFS_8G, AFS_16G
AlanHuchin 0:89cf0851969b 52 uint8_t Gscale = GFS_2000DPS; // GFS_250DPS, GFS_500DPS, GFS_1000DPS, GFS_2000DPS
AlanHuchin 0:89cf0851969b 53 uint8_t Mscale = MFS_16BITS; // MFS_14BITS or MFS_16BITS, 14-bit or 16-bit magnetometer resolution
AlanHuchin 0:89cf0851969b 54 uint8_t Mmode = 0x06; // Either 8 Hz 0x02) or 100 Hz (0x06) magnetometer data ODR
AlanHuchin 0:89cf0851969b 55 float aRes, gRes, mRes;
AlanHuchin 0:89cf0851969b 56
AlanHuchin 0:89cf0851969b 57 MPU9250::MPU9250(PinName sda, PinName scl) : i2c(sda, scl) {
AlanHuchin 0:89cf0851969b 58 //this->setSleepMode(false);
AlanHuchin 0:89cf0851969b 59 i2c.frequency(400000);
AlanHuchin 0:89cf0851969b 60 //Initializations:
AlanHuchin 0:89cf0851969b 61 currentGyroRange = 0;
AlanHuchin 0:89cf0851969b 62 currentAcceleroRange=0;
AlanHuchin 0:89cf0851969b 63 }
AlanHuchin 0:89cf0851969b 64
AlanHuchin 0:89cf0851969b 65 //--------------------------------------------------
AlanHuchin 0:89cf0851969b 66 //--------------------CONFIG------------------------
AlanHuchin 0:89cf0851969b 67 //--------------------------------------------------
AlanHuchin 0:89cf0851969b 68
AlanHuchin 0:89cf0851969b 69 void MPU9250::getAres()
AlanHuchin 0:89cf0851969b 70 {
AlanHuchin 0:89cf0851969b 71 switch(Ascale)
AlanHuchin 0:89cf0851969b 72 {
AlanHuchin 0:89cf0851969b 73 case AFS_2G:
AlanHuchin 0:89cf0851969b 74 aRes = 2.0/32768.0;
AlanHuchin 0:89cf0851969b 75 break;
AlanHuchin 0:89cf0851969b 76 case AFS_4G:
AlanHuchin 0:89cf0851969b 77 aRes = 4.0/32768.0;
AlanHuchin 0:89cf0851969b 78 break;
AlanHuchin 0:89cf0851969b 79 case AFS_8G:
AlanHuchin 0:89cf0851969b 80 aRes = 8.0/32768.0;
AlanHuchin 0:89cf0851969b 81 break;
AlanHuchin 0:89cf0851969b 82 case AFS_16G:
AlanHuchin 0:89cf0851969b 83 aRes = 16.0/32768.0;
AlanHuchin 0:89cf0851969b 84 break;
AlanHuchin 0:89cf0851969b 85 }
AlanHuchin 0:89cf0851969b 86 }
AlanHuchin 0:89cf0851969b 87
AlanHuchin 0:89cf0851969b 88 void MPU9250::getGres()
AlanHuchin 0:89cf0851969b 89 {
AlanHuchin 0:89cf0851969b 90 switch(Gscale)
AlanHuchin 0:89cf0851969b 91 {
AlanHuchin 0:89cf0851969b 92 case GFS_250DPS:
AlanHuchin 0:89cf0851969b 93 gRes = 250.0/32768.0;
AlanHuchin 0:89cf0851969b 94 break;
AlanHuchin 0:89cf0851969b 95 case GFS_500DPS:
AlanHuchin 0:89cf0851969b 96 gRes = 500.0/32768.0;
AlanHuchin 0:89cf0851969b 97 break;
AlanHuchin 0:89cf0851969b 98 case GFS_1000DPS:
AlanHuchin 0:89cf0851969b 99 gRes = 1000.0/32768.0;
AlanHuchin 0:89cf0851969b 100 break;
AlanHuchin 0:89cf0851969b 101 case GFS_2000DPS:
AlanHuchin 0:89cf0851969b 102 gRes = 2000.0/32768.0;
AlanHuchin 0:89cf0851969b 103 break;
AlanHuchin 0:89cf0851969b 104 }
AlanHuchin 0:89cf0851969b 105 }
AlanHuchin 0:89cf0851969b 106
AlanHuchin 0:89cf0851969b 107 void MPU9250::getMres() {
AlanHuchin 0:89cf0851969b 108 switch (Mscale)
AlanHuchin 0:89cf0851969b 109 {
AlanHuchin 0:89cf0851969b 110 // Possible magnetometer scales (and their register bit settings) are:
AlanHuchin 0:89cf0851969b 111 // 14 bit resolution (0) and 16 bit resolution (1)
AlanHuchin 0:89cf0851969b 112 case MFS_14BITS:
AlanHuchin 0:89cf0851969b 113 mRes = 10.0*4219.0/8190.0; // Proper scale to return milliGauss
AlanHuchin 0:89cf0851969b 114 break;
AlanHuchin 0:89cf0851969b 115 case MFS_16BITS:
AlanHuchin 0:89cf0851969b 116 mRes = 10.0*4219.0/32760.0; // Proper scale to return milliGauss
AlanHuchin 0:89cf0851969b 117 break;
AlanHuchin 0:89cf0851969b 118 }
AlanHuchin 0:89cf0851969b 119 }
AlanHuchin 0:89cf0851969b 120 //--------------------------------------------------
AlanHuchin 0:89cf0851969b 121 //-------------------General------------------------
AlanHuchin 0:89cf0851969b 122 //--------------------------------------------------
AlanHuchin 0:89cf0851969b 123
AlanHuchin 0:89cf0851969b 124 void MPU9250::writeByte(uint8_t address, uint8_t subAddress, uint8_t data)
AlanHuchin 0:89cf0851969b 125 {
AlanHuchin 0:89cf0851969b 126 char data_write[2];
AlanHuchin 0:89cf0851969b 127 data_write[0] = subAddress;
AlanHuchin 0:89cf0851969b 128 data_write[1] = data;
AlanHuchin 0:89cf0851969b 129 i2c.write(address, data_write, 2, 0);
AlanHuchin 0:89cf0851969b 130 }
AlanHuchin 0:89cf0851969b 131
AlanHuchin 0:89cf0851969b 132 char MPU9250::readByte(uint8_t address, uint8_t subAddress)
AlanHuchin 0:89cf0851969b 133 {
AlanHuchin 0:89cf0851969b 134 char data[1]; // `data` will store the register data
AlanHuchin 0:89cf0851969b 135 char data_write[1];
AlanHuchin 0:89cf0851969b 136 data_write[0] = subAddress;
AlanHuchin 0:89cf0851969b 137 i2c.write(address, data_write, 1, 1); // no stop
AlanHuchin 0:89cf0851969b 138 i2c.read(address, data, 1, 0);
AlanHuchin 0:89cf0851969b 139 return data[0];
AlanHuchin 0:89cf0851969b 140 }
AlanHuchin 0:89cf0851969b 141
AlanHuchin 0:89cf0851969b 142 void MPU9250::readBytes(uint8_t address, uint8_t subAddress, uint8_t count, uint8_t * dest)
AlanHuchin 0:89cf0851969b 143 {
AlanHuchin 0:89cf0851969b 144 char data[14];
AlanHuchin 0:89cf0851969b 145 char data_write[1];
AlanHuchin 0:89cf0851969b 146 data_write[0] = subAddress;
AlanHuchin 0:89cf0851969b 147 i2c.write(address, data_write, 1, 1); // no stop
AlanHuchin 0:89cf0851969b 148 i2c.read(address, data, count, 0);
AlanHuchin 0:89cf0851969b 149 for(int ii = 0; ii < count; ii++) {
AlanHuchin 0:89cf0851969b 150 dest[ii] = data[ii];
AlanHuchin 0:89cf0851969b 151 }
AlanHuchin 0:89cf0851969b 152 }
AlanHuchin 0:89cf0851969b 153
AlanHuchin 0:89cf0851969b 154
AlanHuchin 0:89cf0851969b 155 void MPU9250::readAccelData(int16_t * destination)
AlanHuchin 0:89cf0851969b 156 {
AlanHuchin 0:89cf0851969b 157 uint8_t rawData[6]; // x/y/z accel register data stored here
AlanHuchin 0:89cf0851969b 158 readBytes(MPU9250_ADDRESS, ACCEL_XOUT_H, 6, &rawData[0]); // Read the six raw data registers into data array
AlanHuchin 0:89cf0851969b 159 destination[0] = (int16_t)(((int16_t)rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value
AlanHuchin 0:89cf0851969b 160 destination[1] = (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ;
AlanHuchin 0:89cf0851969b 161 destination[2] = (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ;
AlanHuchin 0:89cf0851969b 162 }
AlanHuchin 0:89cf0851969b 163
AlanHuchin 0:89cf0851969b 164 void MPU9250::readGyroData(int16_t * destination)
AlanHuchin 0:89cf0851969b 165 {
AlanHuchin 0:89cf0851969b 166 uint8_t rawData[6]; // x/y/z gyro register data stored here
AlanHuchin 0:89cf0851969b 167 readBytes(MPU9250_ADDRESS, GYRO_XOUT_H, 6, &rawData[0]); // Read the six raw data registers sequentially into data array
AlanHuchin 0:89cf0851969b 168 destination[0] = (int16_t)(((int16_t)rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value
AlanHuchin 0:89cf0851969b 169 destination[1] = (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ;
AlanHuchin 0:89cf0851969b 170 destination[2] = (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ;
AlanHuchin 0:89cf0851969b 171 }
AlanHuchin 0:89cf0851969b 172
AlanHuchin 0:89cf0851969b 173 void MPU9250::readMagData(int16_t * destination)
AlanHuchin 0:89cf0851969b 174 {
AlanHuchin 0:89cf0851969b 175 uint8_t rawData[7]; // x/y/z gyro register data, ST2 register stored here, must read ST2 at end of data acquisition
AlanHuchin 0:89cf0851969b 176 if(readByte(AK8963_ADDRESS, AK8963_ST1) & 0x01) { // wait for magnetometer data ready bit to be set
AlanHuchin 0:89cf0851969b 177 readBytes(AK8963_ADDRESS, AK8963_XOUT_L, 7, &rawData[0]); // Read the six raw data and ST2 registers sequentially into data array
AlanHuchin 0:89cf0851969b 178 uint8_t c = rawData[6]; // End data read by reading ST2 register
AlanHuchin 0:89cf0851969b 179 if(!(c & 0x08)) { // Check if magnetic sensor overflow set, if not then report data
AlanHuchin 0:89cf0851969b 180 destination[0] = (int16_t)(((int16_t)rawData[1] << 8) | rawData[0]); // Turn the MSB and LSB into a signed 16-bit value
AlanHuchin 0:89cf0851969b 181 destination[1] = (int16_t)(((int16_t)rawData[3] << 8) | rawData[2]) ; // Data stored as little Endian
AlanHuchin 0:89cf0851969b 182 destination[2] = (int16_t)(((int16_t)rawData[5] << 8) | rawData[4]) ;
AlanHuchin 0:89cf0851969b 183 }
AlanHuchin 0:89cf0851969b 184 }
AlanHuchin 0:89cf0851969b 185 }
AlanHuchin 0:89cf0851969b 186
AlanHuchin 0:89cf0851969b 187 int16_t MPU9250::readTempData()
AlanHuchin 0:89cf0851969b 188 {
AlanHuchin 0:89cf0851969b 189 uint8_t rawData[2]; // x/y/z gyro register data stored here
AlanHuchin 0:89cf0851969b 190 readBytes(MPU9250_ADDRESS, TEMP_OUT_H, 2, &rawData[0]); // Read the two raw data registers sequentially into data array
AlanHuchin 0:89cf0851969b 191 return (int16_t)(((int16_t)rawData[0]) << 8 | rawData[1]) ; // Turn the MSB and LSB into a 16-bit value
AlanHuchin 0:89cf0851969b 192 }
AlanHuchin 0:89cf0851969b 193
AlanHuchin 0:89cf0851969b 194 void MPU9250::resetMPU9250() {
AlanHuchin 0:89cf0851969b 195 // reset device
AlanHuchin 0:89cf0851969b 196 writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x80); // Write a one to bit 7 reset bit; toggle reset device
AlanHuchin 0:89cf0851969b 197 wait(0.1);
AlanHuchin 0:89cf0851969b 198 }
AlanHuchin 0:89cf0851969b 199
AlanHuchin 0:89cf0851969b 200 void MPU9250::initAK8963(float * destination)
AlanHuchin 0:89cf0851969b 201 {
AlanHuchin 0:89cf0851969b 202 // First extract the factory calibration for each magnetometer axis
AlanHuchin 0:89cf0851969b 203 uint8_t rawData[3]; // x/y/z gyro calibration data stored here
AlanHuchin 0:89cf0851969b 204 writeByte(AK8963_ADDRESS, AK8963_CNTL, 0x00); // Power down magnetometer
AlanHuchin 0:89cf0851969b 205 wait(0.01);
AlanHuchin 0:89cf0851969b 206 writeByte(AK8963_ADDRESS, AK8963_CNTL, 0x0F); // Enter Fuse ROM access mode
AlanHuchin 0:89cf0851969b 207 wait(0.01);
AlanHuchin 0:89cf0851969b 208 readBytes(AK8963_ADDRESS, AK8963_ASAX, 3, &rawData[0]); // Read the x-, y-, and z-axis calibration values
AlanHuchin 0:89cf0851969b 209 destination[0] = (float)(rawData[0] - 128)/256.0f + 1.0f; // Return x-axis sensitivity adjustment values, etc.
AlanHuchin 0:89cf0851969b 210 destination[1] = (float)(rawData[1] - 128)/256.0f + 1.0f;
AlanHuchin 0:89cf0851969b 211 destination[2] = (float)(rawData[2] - 128)/256.0f + 1.0f;
AlanHuchin 0:89cf0851969b 212 writeByte(AK8963_ADDRESS, AK8963_CNTL, 0x00); // Power down magnetometer
AlanHuchin 0:89cf0851969b 213 wait(0.01);
AlanHuchin 0:89cf0851969b 214 // Configure the magnetometer for continuous read and highest resolution
AlanHuchin 0:89cf0851969b 215 // set Mscale bit 4 to 1 (0) to enable 16 (14) bit resolution in CNTL register,
AlanHuchin 0:89cf0851969b 216 // and enable continuous mode data acquisition Mmode (bits [3:0]), 0010 for 8 Hz and 0110 for 100 Hz sample rates
AlanHuchin 0:89cf0851969b 217 writeByte(AK8963_ADDRESS, AK8963_CNTL, Mscale << 4 | Mmode); // Set magnetometer data resolution and sample ODR
AlanHuchin 0:89cf0851969b 218 wait(0.01);
AlanHuchin 0:89cf0851969b 219 }
AlanHuchin 0:89cf0851969b 220
AlanHuchin 0:89cf0851969b 221 void MPU9250::initMPU9250()
AlanHuchin 0:89cf0851969b 222 {
AlanHuchin 0:89cf0851969b 223 // Initialize MPU9250 device
AlanHuchin 0:89cf0851969b 224 // wake up device
AlanHuchin 0:89cf0851969b 225 writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x00); // Clear sleep mode bit (6), enable all sensors
AlanHuchin 0:89cf0851969b 226 wait(0.1); // Delay 100 ms for PLL to get established on x-axis gyro; should check for PLL ready interrupt
AlanHuchin 0:89cf0851969b 227
AlanHuchin 0:89cf0851969b 228 // get stable time source
AlanHuchin 0:89cf0851969b 229 writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x01); // Set clock source to be PLL with x-axis gyroscope reference, bits 2:0 = 001
AlanHuchin 0:89cf0851969b 230
AlanHuchin 0:89cf0851969b 231 // Configure Gyro and Accelerometer
AlanHuchin 0:89cf0851969b 232 // Disable FSYNC and set accelerometer and gyro bandwidth to 44 and 42 Hz, respectively;
AlanHuchin 0:89cf0851969b 233 // DLPF_CFG = bits 2:0 = 010; this sets the sample rate at 1 kHz for both
AlanHuchin 0:89cf0851969b 234 // Maximum delay is 4.9 ms which is just over a 200 Hz maximum rate
AlanHuchin 0:89cf0851969b 235 writeByte(MPU9250_ADDRESS, CONFIG, 0x03);
AlanHuchin 0:89cf0851969b 236
AlanHuchin 0:89cf0851969b 237 // Set sample rate = gyroscope output rate/(1 + SMPLRT_DIV)
AlanHuchin 0:89cf0851969b 238 writeByte(MPU9250_ADDRESS, SMPLRT_DIV, 0x04); // Use a 200 Hz rate; the same rate set in CONFIG above
AlanHuchin 0:89cf0851969b 239
AlanHuchin 0:89cf0851969b 240 // Set gyroscope full scale range
AlanHuchin 0:89cf0851969b 241 // Range selects FS_SEL and AFS_SEL are 0 - 3, so 2-bit values are left-shifted into positions 4:3
AlanHuchin 0:89cf0851969b 242 uint8_t c = readByte(MPU9250_ADDRESS, GYRO_CONFIG); // get current GYRO_CONFIG register value
AlanHuchin 0:89cf0851969b 243 // c = c & ~0xE0; // Clear self-test bits [7:5]
AlanHuchin 0:89cf0851969b 244 c = c & ~0x02; // Clear Fchoice bits [1:0]
AlanHuchin 0:89cf0851969b 245 c = c & ~0x18; // Clear AFS bits [4:3]
AlanHuchin 0:89cf0851969b 246 c = c | Gscale << 3; // Set full scale range for the gyro
AlanHuchin 0:89cf0851969b 247 // c =| 0x00; // Set Fchoice for the gyro to 11 by writing its inverse to bits 1:0 of GYRO_CONFIG
AlanHuchin 0:89cf0851969b 248 writeByte(MPU9250_ADDRESS, GYRO_CONFIG, c ); // Write new GYRO_CONFIG value to register
AlanHuchin 0:89cf0851969b 249
AlanHuchin 0:89cf0851969b 250 // Set accelerometer full-scale range configuration
AlanHuchin 0:89cf0851969b 251 c = readByte(MPU9250_ADDRESS, ACCEL_CONFIG); // get current ACCEL_CONFIG register value
AlanHuchin 0:89cf0851969b 252 // c = c & ~0xE0; // Clear self-test bits [7:5]
AlanHuchin 0:89cf0851969b 253 c = c & ~0x18; // Clear AFS bits [4:3]
AlanHuchin 0:89cf0851969b 254 c = c | Ascale << 3; // Set full scale range for the accelerometer
AlanHuchin 0:89cf0851969b 255 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, c); // Write new ACCEL_CONFIG register value
AlanHuchin 0:89cf0851969b 256
AlanHuchin 0:89cf0851969b 257 // Set accelerometer sample rate configuration
AlanHuchin 0:89cf0851969b 258 // It is possible to get a 4 kHz sample rate from the accelerometer by choosing 1 for
AlanHuchin 0:89cf0851969b 259 // accel_fchoice_b bit [3]; in this case the bandwidth is 1.13 kHz
AlanHuchin 0:89cf0851969b 260 c = readByte(MPU9250_ADDRESS, ACCEL_CONFIG2); // get current ACCEL_CONFIG2 register value
AlanHuchin 0:89cf0851969b 261 c = c & ~0x0F; // Clear accel_fchoice_b (bit 3) and A_DLPFG (bits [2:0])
AlanHuchin 0:89cf0851969b 262 c = c | 0x03; // Set accelerometer rate to 1 kHz and bandwidth to 41 Hz
AlanHuchin 0:89cf0851969b 263 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG2, c); // Write new ACCEL_CONFIG2 register value
AlanHuchin 0:89cf0851969b 264
AlanHuchin 0:89cf0851969b 265 // The accelerometer, gyro, and thermometer are set to 1 kHz sample rates,
AlanHuchin 0:89cf0851969b 266 // but all these rates are further reduced by a factor of 5 to 200 Hz because of the SMPLRT_DIV setting
AlanHuchin 0:89cf0851969b 267
AlanHuchin 0:89cf0851969b 268 // Configure Interrupts and Bypass Enable
AlanHuchin 0:89cf0851969b 269 // Set interrupt pin active high, push-pull, and clear on read of INT_STATUS, enable I2C_BYPASS_EN so additional chips
AlanHuchin 0:89cf0851969b 270 // can join the I2C bus and all can be controlled by the Arduino as master
AlanHuchin 0:89cf0851969b 271
AlanHuchin 0:89cf0851969b 272 #if USE_ISR
AlanHuchin 0:89cf0851969b 273 writeByte(MPU9250_ADDRESS, INT_PIN_CFG, 0x12); // INT is 50 microsecond pulse and any read to clear
AlanHuchin 0:89cf0851969b 274 #else
AlanHuchin 0:89cf0851969b 275 writeByte(MPU9250_ADDRESS, INT_PIN_CFG, 0x22);
AlanHuchin 0:89cf0851969b 276 #endif
AlanHuchin 0:89cf0851969b 277 writeByte(MPU9250_ADDRESS, INT_ENABLE, 0x01); // Enable data ready (bit 0) interrupt
AlanHuchin 0:89cf0851969b 278 }
AlanHuchin 0:89cf0851969b 279
AlanHuchin 0:89cf0851969b 280 // Function which accumulates gyro and accelerometer data after device initialization. It calculates the average
AlanHuchin 0:89cf0851969b 281 // of the at-rest readings and then loads the resulting offsets into accelerometer and gyro bias registers.
AlanHuchin 0:89cf0851969b 282 void MPU9250::calibrateMPU9250(float * dest1, float * dest2)
AlanHuchin 0:89cf0851969b 283 {
AlanHuchin 0:89cf0851969b 284 uint8_t data[12]; // data array to hold accelerometer and gyro x, y, z, data
AlanHuchin 0:89cf0851969b 285 uint16_t ii, packet_count, fifo_count;
AlanHuchin 0:89cf0851969b 286 int32_t gyro_bias[3] = {0, 0, 0}, accel_bias[3] = {0, 0, 0};
AlanHuchin 0:89cf0851969b 287
AlanHuchin 0:89cf0851969b 288 // reset device, reset all registers, clear gyro and accelerometer bias registers
AlanHuchin 0:89cf0851969b 289 writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x80); // Write a one to bit 7 reset bit; toggle reset device
AlanHuchin 0:89cf0851969b 290 wait(0.1);
AlanHuchin 0:89cf0851969b 291
AlanHuchin 0:89cf0851969b 292 // get stable time source
AlanHuchin 0:89cf0851969b 293 // Set clock source to be PLL with x-axis gyroscope reference, bits 2:0 = 001
AlanHuchin 0:89cf0851969b 294 writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x01);
AlanHuchin 0:89cf0851969b 295 writeByte(MPU9250_ADDRESS, PWR_MGMT_2, 0x00);
AlanHuchin 0:89cf0851969b 296 wait(0.2);
AlanHuchin 0:89cf0851969b 297
AlanHuchin 0:89cf0851969b 298 // Configure device for bias calculation
AlanHuchin 0:89cf0851969b 299 writeByte(MPU9250_ADDRESS, INT_ENABLE, 0x00); // Disable all interrupts
AlanHuchin 0:89cf0851969b 300 writeByte(MPU9250_ADDRESS, FIFO_EN, 0x00); // Disable FIFO
AlanHuchin 0:89cf0851969b 301 writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x00); // Turn on internal clock source
AlanHuchin 0:89cf0851969b 302 writeByte(MPU9250_ADDRESS, I2C_MST_CTRL, 0x00); // Disable I2C master
AlanHuchin 0:89cf0851969b 303 writeByte(MPU9250_ADDRESS, USER_CTRL, 0x00); // Disable FIFO and I2C master modes
AlanHuchin 0:89cf0851969b 304 writeByte(MPU9250_ADDRESS, USER_CTRL, 0x0C); // Reset FIFO and DMP
AlanHuchin 0:89cf0851969b 305 wait(0.015);
AlanHuchin 0:89cf0851969b 306
AlanHuchin 0:89cf0851969b 307 // Configure MPU9250 gyro and accelerometer for bias calculation
AlanHuchin 0:89cf0851969b 308 writeByte(MPU9250_ADDRESS, CONFIG, 0x01); // Set low-pass filter to 188 Hz
AlanHuchin 0:89cf0851969b 309 writeByte(MPU9250_ADDRESS, SMPLRT_DIV, 0x00); // Set sample rate to 1 kHz
AlanHuchin 0:89cf0851969b 310 writeByte(MPU9250_ADDRESS, GYRO_CONFIG, 0x00); // Set gyro full-scale to 250 degrees per second, maximum sensitivity
AlanHuchin 0:89cf0851969b 311 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, 0x00); // Set accelerometer full-scale to 2 g, maximum sensitivity
AlanHuchin 0:89cf0851969b 312
AlanHuchin 0:89cf0851969b 313 uint16_t gyrosensitivity = 131; // = 131 LSB/degrees/sec
AlanHuchin 0:89cf0851969b 314 uint16_t accelsensitivity = 16384; // = 16384 LSB/g
AlanHuchin 0:89cf0851969b 315
AlanHuchin 0:89cf0851969b 316 // Configure FIFO to capture accelerometer and gyro data for bias calculation
AlanHuchin 0:89cf0851969b 317 writeByte(MPU9250_ADDRESS, USER_CTRL, 0x40); // Enable FIFO
AlanHuchin 0:89cf0851969b 318 writeByte(MPU9250_ADDRESS, FIFO_EN, 0x78); // Enable gyro and accelerometer sensors for FIFO (max size 512 bytes in MPU-9250)
AlanHuchin 0:89cf0851969b 319 wait(0.04); // accumulate 40 samples in 80 milliseconds = 480 bytes
AlanHuchin 0:89cf0851969b 320
AlanHuchin 0:89cf0851969b 321 // At end of sample accumulation, turn off FIFO sensor read
AlanHuchin 0:89cf0851969b 322 writeByte(MPU9250_ADDRESS, FIFO_EN, 0x00); // Disable gyro and accelerometer sensors for FIFO
AlanHuchin 0:89cf0851969b 323 readBytes(MPU9250_ADDRESS, FIFO_COUNTH, 2, &data[0]); // read FIFO sample count
AlanHuchin 0:89cf0851969b 324 fifo_count = ((uint16_t)data[0] << 8) | data[1];
AlanHuchin 0:89cf0851969b 325 packet_count = fifo_count/12;// How many sets of full gyro and accelerometer data for averaging
AlanHuchin 0:89cf0851969b 326
AlanHuchin 0:89cf0851969b 327 for (ii = 0; ii < packet_count; ii++) {
AlanHuchin 0:89cf0851969b 328 int16_t accel_temp[3] = {0, 0, 0}, gyro_temp[3] = {0, 0, 0};
AlanHuchin 0:89cf0851969b 329 readBytes(MPU9250_ADDRESS, FIFO_R_W, 12, &data[0]); // read data for averaging
AlanHuchin 0:89cf0851969b 330 accel_temp[0] = (int16_t) (((int16_t)data[0] << 8) | data[1] ) ; // Form signed 16-bit integer for each sample in FIFO
AlanHuchin 0:89cf0851969b 331 accel_temp[1] = (int16_t) (((int16_t)data[2] << 8) | data[3] ) ;
AlanHuchin 0:89cf0851969b 332 accel_temp[2] = (int16_t) (((int16_t)data[4] << 8) | data[5] ) ;
AlanHuchin 0:89cf0851969b 333 gyro_temp[0] = (int16_t) (((int16_t)data[6] << 8) | data[7] ) ;
AlanHuchin 0:89cf0851969b 334 gyro_temp[1] = (int16_t) (((int16_t)data[8] << 8) | data[9] ) ;
AlanHuchin 0:89cf0851969b 335 gyro_temp[2] = (int16_t) (((int16_t)data[10] << 8) | data[11]) ;
AlanHuchin 0:89cf0851969b 336
AlanHuchin 0:89cf0851969b 337 accel_bias[0] += (int32_t) accel_temp[0]; // Sum individual signed 16-bit biases to get accumulated signed 32-bit biases
AlanHuchin 0:89cf0851969b 338 accel_bias[1] += (int32_t) accel_temp[1];
AlanHuchin 0:89cf0851969b 339 accel_bias[2] += (int32_t) accel_temp[2];
AlanHuchin 0:89cf0851969b 340 gyro_bias[0] += (int32_t) gyro_temp[0];
AlanHuchin 0:89cf0851969b 341 gyro_bias[1] += (int32_t) gyro_temp[1];
AlanHuchin 0:89cf0851969b 342 gyro_bias[2] += (int32_t) gyro_temp[2];
AlanHuchin 0:89cf0851969b 343
AlanHuchin 0:89cf0851969b 344 }
AlanHuchin 0:89cf0851969b 345 accel_bias[0] /= (int32_t) packet_count; // Normalize sums to get average count biases
AlanHuchin 0:89cf0851969b 346 accel_bias[1] /= (int32_t) packet_count;
AlanHuchin 0:89cf0851969b 347 accel_bias[2] /= (int32_t) packet_count;
AlanHuchin 0:89cf0851969b 348 gyro_bias[0] /= (int32_t) packet_count;
AlanHuchin 0:89cf0851969b 349 gyro_bias[1] /= (int32_t) packet_count;
AlanHuchin 0:89cf0851969b 350 gyro_bias[2] /= (int32_t) packet_count;
AlanHuchin 0:89cf0851969b 351
AlanHuchin 0:89cf0851969b 352 if(accel_bias[2] > 0L) {accel_bias[2] -= (int32_t) accelsensitivity;} // Remove gravity from the z-axis accelerometer bias calculation
AlanHuchin 0:89cf0851969b 353 else {accel_bias[2] += (int32_t) accelsensitivity;}
AlanHuchin 0:89cf0851969b 354
AlanHuchin 0:89cf0851969b 355 // Construct the gyro biases for push to the hardware gyro bias registers, which are reset to zero upon device startup
AlanHuchin 0:89cf0851969b 356 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
AlanHuchin 0:89cf0851969b 357 data[1] = (-gyro_bias[0]/4) & 0xFF; // Biases are additive, so change sign on calculated average gyro biases
AlanHuchin 0:89cf0851969b 358 data[2] = (-gyro_bias[1]/4 >> 8) & 0xFF;
AlanHuchin 0:89cf0851969b 359 data[3] = (-gyro_bias[1]/4) & 0xFF;
AlanHuchin 0:89cf0851969b 360 data[4] = (-gyro_bias[2]/4 >> 8) & 0xFF;
AlanHuchin 0:89cf0851969b 361 data[5] = (-gyro_bias[2]/4) & 0xFF;
AlanHuchin 0:89cf0851969b 362
AlanHuchin 0:89cf0851969b 363 /// Push gyro biases to hardware registers
AlanHuchin 0:89cf0851969b 364 /* writeByte(MPU9250_ADDRESS, XG_OFFSET_H, data[0]);
AlanHuchin 0:89cf0851969b 365 writeByte(MPU9250_ADDRESS, XG_OFFSET_L, data[1]);
AlanHuchin 0:89cf0851969b 366 writeByte(MPU9250_ADDRESS, YG_OFFSET_H, data[2]);
AlanHuchin 0:89cf0851969b 367 writeByte(MPU9250_ADDRESS, YG_OFFSET_L, data[3]);
AlanHuchin 0:89cf0851969b 368 writeByte(MPU9250_ADDRESS, ZG_OFFSET_H, data[4]);
AlanHuchin 0:89cf0851969b 369 writeByte(MPU9250_ADDRESS, ZG_OFFSET_L, data[5]);
AlanHuchin 0:89cf0851969b 370 */
AlanHuchin 0:89cf0851969b 371 dest1[0] = (float) gyro_bias[0]/(float) gyrosensitivity; // construct gyro bias in deg/s for later manual subtraction
AlanHuchin 0:89cf0851969b 372 dest1[1] = (float) gyro_bias[1]/(float) gyrosensitivity;
AlanHuchin 0:89cf0851969b 373 dest1[2] = (float) gyro_bias[2]/(float) gyrosensitivity;
AlanHuchin 0:89cf0851969b 374
AlanHuchin 0:89cf0851969b 375 // Construct the accelerometer biases for push to the hardware accelerometer bias registers. These registers contain
AlanHuchin 0:89cf0851969b 376 // factory trim values which must be added to the calculated accelerometer biases; on boot up these registers will hold
AlanHuchin 0:89cf0851969b 377 // non-zero values. In addition, bit 0 of the lower byte must be preserved since it is used for temperature
AlanHuchin 0:89cf0851969b 378 // compensation calculations. Accelerometer bias registers expect bias input as 2048 LSB per g, so that
AlanHuchin 0:89cf0851969b 379 // the accelerometer biases calculated above must be divided by 8.
AlanHuchin 0:89cf0851969b 380
AlanHuchin 0:89cf0851969b 381 int32_t accel_bias_reg[3] = {0, 0, 0}; // A place to hold the factory accelerometer trim biases
AlanHuchin 0:89cf0851969b 382 readBytes(MPU9250_ADDRESS, XA_OFFSET_H, 2, &data[0]); // Read factory accelerometer trim values
AlanHuchin 0:89cf0851969b 383 accel_bias_reg[0] = (int16_t) ((int16_t)data[0] << 8) | data[1];
AlanHuchin 0:89cf0851969b 384 readBytes(MPU9250_ADDRESS, YA_OFFSET_H, 2, &data[0]);
AlanHuchin 0:89cf0851969b 385 accel_bias_reg[1] = (int16_t) ((int16_t)data[0] << 8) | data[1];
AlanHuchin 0:89cf0851969b 386 readBytes(MPU9250_ADDRESS, ZA_OFFSET_H, 2, &data[0]);
AlanHuchin 0:89cf0851969b 387 accel_bias_reg[2] = (int16_t) ((int16_t)data[0] << 8) | data[1];
AlanHuchin 0:89cf0851969b 388
AlanHuchin 0:89cf0851969b 389 uint32_t mask = 1uL; // Define mask for temperature compensation bit 0 of lower byte of accelerometer bias registers
AlanHuchin 0:89cf0851969b 390 uint8_t mask_bit[3] = {0, 0, 0}; // Define array to hold mask bit for each accelerometer bias axis
AlanHuchin 0:89cf0851969b 391
AlanHuchin 0:89cf0851969b 392 for(ii = 0; ii < 3; ii++) {
AlanHuchin 0:89cf0851969b 393 if(accel_bias_reg[ii] & mask) mask_bit[ii] = 0x01; // If temperature compensation bit is set, record that fact in mask_bit
AlanHuchin 0:89cf0851969b 394 }
AlanHuchin 0:89cf0851969b 395
AlanHuchin 0:89cf0851969b 396 // Construct total accelerometer bias, including calculated average accelerometer bias from above
AlanHuchin 0:89cf0851969b 397 accel_bias_reg[0] -= (accel_bias[0]/8); // Subtract calculated averaged accelerometer bias scaled to 2048 LSB/g (16 g full scale)
AlanHuchin 0:89cf0851969b 398 accel_bias_reg[1] -= (accel_bias[1]/8);
AlanHuchin 0:89cf0851969b 399 accel_bias_reg[2] -= (accel_bias[2]/8);
AlanHuchin 0:89cf0851969b 400
AlanHuchin 0:89cf0851969b 401 data[0] = (accel_bias_reg[0] >> 8) & 0xFF;
AlanHuchin 0:89cf0851969b 402 data[1] = (accel_bias_reg[0]) & 0xFF;
AlanHuchin 0:89cf0851969b 403 data[1] = data[1] | mask_bit[0]; // preserve temperature compensation bit when writing back to accelerometer bias registers
AlanHuchin 0:89cf0851969b 404 data[2] = (accel_bias_reg[1] >> 8) & 0xFF;
AlanHuchin 0:89cf0851969b 405 data[3] = (accel_bias_reg[1]) & 0xFF;
AlanHuchin 0:89cf0851969b 406 data[3] = data[3] | mask_bit[1]; // preserve temperature compensation bit when writing back to accelerometer bias registers
AlanHuchin 0:89cf0851969b 407 data[4] = (accel_bias_reg[2] >> 8) & 0xFF;
AlanHuchin 0:89cf0851969b 408 data[5] = (accel_bias_reg[2]) & 0xFF;
AlanHuchin 0:89cf0851969b 409 data[5] = data[5] | mask_bit[2]; // preserve temperature compensation bit when writing back to accelerometer bias registers
AlanHuchin 0:89cf0851969b 410
AlanHuchin 0:89cf0851969b 411 // Apparently this is not working for the acceleration biases in the MPU-9250
AlanHuchin 0:89cf0851969b 412 // Are we handling the temperature correction bit properly?
AlanHuchin 0:89cf0851969b 413 // Push accelerometer biases to hardware registers
AlanHuchin 0:89cf0851969b 414 /* writeByte(MPU9250_ADDRESS, XA_OFFSET_H, data[0]);
AlanHuchin 0:89cf0851969b 415 writeByte(MPU9250_ADDRESS, XA_OFFSET_L, data[1]);
AlanHuchin 0:89cf0851969b 416 writeByte(MPU9250_ADDRESS, YA_OFFSET_H, data[2]);
AlanHuchin 0:89cf0851969b 417 writeByte(MPU9250_ADDRESS, YA_OFFSET_L, data[3]);
AlanHuchin 0:89cf0851969b 418 writeByte(MPU9250_ADDRESS, ZA_OFFSET_H, data[4]);
AlanHuchin 0:89cf0851969b 419 writeByte(MPU9250_ADDRESS, ZA_OFFSET_L, data[5]);
AlanHuchin 0:89cf0851969b 420 */
AlanHuchin 0:89cf0851969b 421 // Output scaled accelerometer biases for manual subtraction in the main program
AlanHuchin 0:89cf0851969b 422 dest2[0] = (float)accel_bias[0]/(float)accelsensitivity;
AlanHuchin 0:89cf0851969b 423 dest2[1] = (float)accel_bias[1]/(float)accelsensitivity;
AlanHuchin 0:89cf0851969b 424 dest2[2] = (float)accel_bias[2]/(float)accelsensitivity;
AlanHuchin 0:89cf0851969b 425 }
AlanHuchin 0:89cf0851969b 426
AlanHuchin 0:89cf0851969b 427 void MPU9250::magcalMPU9250(float * dest1, float * dest2)
AlanHuchin 0:89cf0851969b 428 {
AlanHuchin 0:89cf0851969b 429 uint16_t ii = 0, sample_count = 0;
AlanHuchin 0:89cf0851969b 430 int32_t mag_bias[3] = {0, 0, 0}, mag_scale[3] = {0, 0, 0};
AlanHuchin 0:89cf0851969b 431 int16_t mag_max[3] = {-32767, -32767, -32767}, mag_min[3] = {32767, 32767, 32767}, mag_temp[3] = {0, 0, 0};
AlanHuchin 0:89cf0851969b 432
AlanHuchin 0:89cf0851969b 433 // shoot for ~fifteen seconds of mag data
AlanHuchin 0:89cf0851969b 434 if(Mmode == 0x02) sample_count = 128; // at 8 Hz ODR, new mag data is available every 125 ms
AlanHuchin 0:89cf0851969b 435 if(Mmode == 0x06) sample_count = 1500; // at 100 Hz ODR, new mag data is available every 10 ms
AlanHuchin 0:89cf0851969b 436
AlanHuchin 0:89cf0851969b 437 for(ii = 0; ii < sample_count; ii++) {
AlanHuchin 0:89cf0851969b 438 readMagData(mag_temp); // Read the mag data
AlanHuchin 0:89cf0851969b 439
AlanHuchin 0:89cf0851969b 440 for (int jj = 0; jj < 3; jj++) {
AlanHuchin 0:89cf0851969b 441 if(mag_temp[jj] > mag_max[jj]) mag_max[jj] = mag_temp[jj];
AlanHuchin 0:89cf0851969b 442 if(mag_temp[jj] < mag_min[jj]) mag_min[jj] = mag_temp[jj];
AlanHuchin 0:89cf0851969b 443 }
AlanHuchin 0:89cf0851969b 444
AlanHuchin 0:89cf0851969b 445 if(Mmode == 0x02) wait(0.135); // at 8 Hz ODR, new mag data is available every 125 ms
AlanHuchin 0:89cf0851969b 446 if(Mmode == 0x06) wait(0.012); // at 100 Hz ODR, new mag data is available every 10 ms
AlanHuchin 0:89cf0851969b 447 }
AlanHuchin 0:89cf0851969b 448
AlanHuchin 0:89cf0851969b 449 // Get hard iron correction
AlanHuchin 0:89cf0851969b 450 mag_bias[0] = (mag_max[0] + mag_min[0])/2; // get average x mag bias in counts
AlanHuchin 0:89cf0851969b 451 mag_bias[1] = (mag_max[1] + mag_min[1])/2; // get average y mag bias in counts
AlanHuchin 0:89cf0851969b 452 mag_bias[2] = (mag_max[2] + mag_min[2])/2; // get average z mag bias in counts
AlanHuchin 0:89cf0851969b 453
AlanHuchin 0:89cf0851969b 454 dest1[0] = (float) mag_bias[0]*mRes*magCalibration[0]; // save mag biases in G for main program
AlanHuchin 0:89cf0851969b 455 dest1[1] = (float) mag_bias[1]*mRes*magCalibration[1];
AlanHuchin 0:89cf0851969b 456 dest1[2] = (float) mag_bias[2]*mRes*magCalibration[2];
AlanHuchin 0:89cf0851969b 457
AlanHuchin 0:89cf0851969b 458 // Get soft iron correction estimate
AlanHuchin 0:89cf0851969b 459 mag_scale[0] = (mag_max[0] - mag_min[0])/2; // get average x axis max chord length in counts
AlanHuchin 0:89cf0851969b 460 mag_scale[1] = (mag_max[1] - mag_min[1])/2; // get average y axis max chord length in counts
AlanHuchin 0:89cf0851969b 461 mag_scale[2] = (mag_max[2] - mag_min[2])/2; // get average z axis max chord length in counts
AlanHuchin 0:89cf0851969b 462
AlanHuchin 0:89cf0851969b 463 float avg_rad = mag_scale[0] + mag_scale[1] + mag_scale[2];
AlanHuchin 0:89cf0851969b 464 avg_rad /= 3.0;
AlanHuchin 0:89cf0851969b 465
AlanHuchin 0:89cf0851969b 466 dest2[0] = avg_rad/((float)mag_scale[0]);
AlanHuchin 0:89cf0851969b 467 dest2[1] = avg_rad/((float)mag_scale[1]);
AlanHuchin 0:89cf0851969b 468 dest2[2] = avg_rad/((float)mag_scale[2]);
AlanHuchin 0:89cf0851969b 469 }
AlanHuchin 0:89cf0851969b 470
AlanHuchin 0:89cf0851969b 471
AlanHuchin 0:89cf0851969b 472 // Accelerometer and gyroscope self test; check calibration wrt factory settings
AlanHuchin 0:89cf0851969b 473 void MPU9250::MPU9250SelfTest(float * destination) // Should return percent deviation from factory trim values, +/- 14 or less deviation is a pass
AlanHuchin 0:89cf0851969b 474 {
AlanHuchin 0:89cf0851969b 475 uint8_t rawData[6] = {0, 0, 0, 0, 0, 0};
AlanHuchin 0:89cf0851969b 476 uint8_t selfTest[6];
AlanHuchin 0:89cf0851969b 477 int32_t gAvg[3] = {0}, aAvg[3] = {0}, aSTAvg[3] = {0}, gSTAvg[3] = {0};
AlanHuchin 0:89cf0851969b 478 float factoryTrim[6];
AlanHuchin 0:89cf0851969b 479 uint8_t FS = 0;
AlanHuchin 0:89cf0851969b 480
AlanHuchin 0:89cf0851969b 481 writeByte(MPU9250_ADDRESS, SMPLRT_DIV, 0x00); // Set gyro sample rate to 1 kHz
AlanHuchin 0:89cf0851969b 482 writeByte(MPU9250_ADDRESS, CONFIG, 0x02); // Set gyro sample rate to 1 kHz and DLPF to 92 Hz
AlanHuchin 0:89cf0851969b 483 writeByte(MPU9250_ADDRESS, GYRO_CONFIG, 1<<FS); // Set full scale range for the gyro to 250 dps
AlanHuchin 0:89cf0851969b 484 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG2, 0x02); // Set accelerometer rate to 1 kHz and bandwidth to 92 Hz
AlanHuchin 0:89cf0851969b 485 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, 1<<FS); // Set full scale range for the accelerometer to 2 g
AlanHuchin 0:89cf0851969b 486
AlanHuchin 0:89cf0851969b 487 for( int ii = 0; ii < 200; ii++) { // get average current values of gyro and acclerometer
AlanHuchin 0:89cf0851969b 488
AlanHuchin 0:89cf0851969b 489 readBytes(MPU9250_ADDRESS, ACCEL_XOUT_H, 6, &rawData[0]); // Read the six raw data registers into data array
AlanHuchin 0:89cf0851969b 490 aAvg[0] += (int16_t)(((int16_t)rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value
AlanHuchin 0:89cf0851969b 491 aAvg[1] += (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ;
AlanHuchin 0:89cf0851969b 492 aAvg[2] += (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ;
AlanHuchin 0:89cf0851969b 493
AlanHuchin 0:89cf0851969b 494 readBytes(MPU9250_ADDRESS, GYRO_XOUT_H, 6, &rawData[0]); // Read the six raw data registers sequentially into data array
AlanHuchin 0:89cf0851969b 495 gAvg[0] += (int16_t)(((int16_t)rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value
AlanHuchin 0:89cf0851969b 496 gAvg[1] += (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ;
AlanHuchin 0:89cf0851969b 497 gAvg[2] += (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ;
AlanHuchin 0:89cf0851969b 498 }
AlanHuchin 0:89cf0851969b 499
AlanHuchin 0:89cf0851969b 500 for (int ii =0; ii < 3; ii++) { // Get average of 200 values and store as average current readings
AlanHuchin 0:89cf0851969b 501 aAvg[ii] /= 200;
AlanHuchin 0:89cf0851969b 502 gAvg[ii] /= 200;
AlanHuchin 0:89cf0851969b 503 }
AlanHuchin 0:89cf0851969b 504
AlanHuchin 0:89cf0851969b 505 // Configure the accelerometer for self-test
AlanHuchin 0:89cf0851969b 506 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, 0xE0); // Enable self test on all three axes and set accelerometer range to +/- 2 g
AlanHuchin 0:89cf0851969b 507 writeByte(MPU9250_ADDRESS, GYRO_CONFIG, 0xE0); // Enable self test on all three axes and set gyro range to +/- 250 degrees/s
AlanHuchin 0:89cf0851969b 508 wait(0.025); // Delay a while to let the device stabilize
AlanHuchin 0:89cf0851969b 509
AlanHuchin 0:89cf0851969b 510 for( int ii = 0; ii < 200; ii++) { // get average self-test values of gyro and acclerometer
AlanHuchin 0:89cf0851969b 511
AlanHuchin 0:89cf0851969b 512 readBytes(MPU9250_ADDRESS, ACCEL_XOUT_H, 6, &rawData[0]); // Read the six raw data registers into data array
AlanHuchin 0:89cf0851969b 513 aSTAvg[0] += (int16_t)(((int16_t)rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value
AlanHuchin 0:89cf0851969b 514 aSTAvg[1] += (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ;
AlanHuchin 0:89cf0851969b 515 aSTAvg[2] += (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ;
AlanHuchin 0:89cf0851969b 516
AlanHuchin 0:89cf0851969b 517 readBytes(MPU9250_ADDRESS, GYRO_XOUT_H, 6, &rawData[0]); // Read the six raw data registers sequentially into data array
AlanHuchin 0:89cf0851969b 518 gSTAvg[0] += (int16_t)(((int16_t)rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value
AlanHuchin 0:89cf0851969b 519 gSTAvg[1] += (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ;
AlanHuchin 0:89cf0851969b 520 gSTAvg[2] += (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ;
AlanHuchin 0:89cf0851969b 521 }
AlanHuchin 0:89cf0851969b 522
AlanHuchin 0:89cf0851969b 523 for (int ii =0; ii < 3; ii++) { // Get average of 200 values and store as average self-test readings
AlanHuchin 0:89cf0851969b 524 aSTAvg[ii] /= 200;
AlanHuchin 0:89cf0851969b 525 gSTAvg[ii] /= 200;
AlanHuchin 0:89cf0851969b 526 }
AlanHuchin 0:89cf0851969b 527
AlanHuchin 0:89cf0851969b 528 // Configure the gyro and accelerometer for normal operation
AlanHuchin 0:89cf0851969b 529 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, 0x00);
AlanHuchin 0:89cf0851969b 530 writeByte(MPU9250_ADDRESS, GYRO_CONFIG, 0x00);
AlanHuchin 0:89cf0851969b 531 wait(0.025); // Delay a while to let the device stabilize
AlanHuchin 0:89cf0851969b 532
AlanHuchin 0:89cf0851969b 533 // Retrieve accelerometer and gyro factory Self-Test Code from USR_Reg
AlanHuchin 0:89cf0851969b 534 selfTest[0] = readByte(MPU9250_ADDRESS, SELF_TEST_X_ACCEL); // X-axis accel self-test results
AlanHuchin 0:89cf0851969b 535 selfTest[1] = readByte(MPU9250_ADDRESS, SELF_TEST_Y_ACCEL); // Y-axis accel self-test results
AlanHuchin 0:89cf0851969b 536 selfTest[2] = readByte(MPU9250_ADDRESS, SELF_TEST_Z_ACCEL); // Z-axis accel self-test results
AlanHuchin 0:89cf0851969b 537 selfTest[3] = readByte(MPU9250_ADDRESS, SELF_TEST_X_GYRO); // X-axis gyro self-test results
AlanHuchin 0:89cf0851969b 538 selfTest[4] = readByte(MPU9250_ADDRESS, SELF_TEST_Y_GYRO); // Y-axis gyro self-test results
AlanHuchin 0:89cf0851969b 539 selfTest[5] = readByte(MPU9250_ADDRESS, SELF_TEST_Z_GYRO); // Z-axis gyro self-test results
AlanHuchin 0:89cf0851969b 540
AlanHuchin 0:89cf0851969b 541 // Retrieve factory self-test value from self-test code reads
AlanHuchin 0:89cf0851969b 542 factoryTrim[0] = (float)(2620/1<<FS)*(pow( 1.01 , ((float)selfTest[0] - 1.0) )); // FT[Xa] factory trim calculation
AlanHuchin 0:89cf0851969b 543 factoryTrim[1] = (float)(2620/1<<FS)*(pow( 1.01 , ((float)selfTest[1] - 1.0) )); // FT[Ya] factory trim calculation
AlanHuchin 0:89cf0851969b 544 factoryTrim[2] = (float)(2620/1<<FS)*(pow( 1.01 , ((float)selfTest[2] - 1.0) )); // FT[Za] factory trim calculation
AlanHuchin 0:89cf0851969b 545 factoryTrim[3] = (float)(2620/1<<FS)*(pow( 1.01 , ((float)selfTest[3] - 1.0) )); // FT[Xg] factory trim calculation
AlanHuchin 0:89cf0851969b 546 factoryTrim[4] = (float)(2620/1<<FS)*(pow( 1.01 , ((float)selfTest[4] - 1.0) )); // FT[Yg] factory trim calculation
AlanHuchin 0:89cf0851969b 547 factoryTrim[5] = (float)(2620/1<<FS)*(pow( 1.01 , ((float)selfTest[5] - 1.0) )); // FT[Zg] factory trim calculation
AlanHuchin 0:89cf0851969b 548
AlanHuchin 0:89cf0851969b 549 // Report results as a ratio of (STR - FT)/FT; the change from Factory Trim of the Self-Test Response
AlanHuchin 0:89cf0851969b 550 // To get percent, must multiply by 100
AlanHuchin 0:89cf0851969b 551 for (int i = 0; i < 3; i++) {
AlanHuchin 0:89cf0851969b 552 destination[i] = 100.0*((float)(aSTAvg[i] - aAvg[i]))/factoryTrim[i] - 100.; // Report percent differences
AlanHuchin 0:89cf0851969b 553 destination[i+3] = 100.0*((float)(gSTAvg[i] - gAvg[i]))/factoryTrim[i+3] - 100.; // Report percent differences
AlanHuchin 0:89cf0851969b 554 }
AlanHuchin 0:89cf0851969b 555
AlanHuchin 0:89cf0851969b 556 }
AlanHuchin 0:89cf0851969b 557
AlanHuchin 0:89cf0851969b 558 void MPU9250::MadgwickQuaternionUpdate(float ax, float ay, float az, float gx, float gy, float gz, float mx, float my, float mz)
AlanHuchin 0:89cf0851969b 559 {
AlanHuchin 0:89cf0851969b 560 float q1 = q[0], q2 = q[1], q3 = q[2], q4 = q[3]; // short name local variable for readability
AlanHuchin 0:89cf0851969b 561 float norm;
AlanHuchin 0:89cf0851969b 562 float hx, hy, _2bx, _2bz;
AlanHuchin 0:89cf0851969b 563 float s1, s2, s3, s4;
AlanHuchin 0:89cf0851969b 564 float qDot1, qDot2, qDot3, qDot4;
AlanHuchin 0:89cf0851969b 565
AlanHuchin 0:89cf0851969b 566 // Auxiliary variables to avoid repeated arithmetic
AlanHuchin 0:89cf0851969b 567 float _2q1mx;
AlanHuchin 0:89cf0851969b 568 float _2q1my;
AlanHuchin 0:89cf0851969b 569 float _2q1mz;
AlanHuchin 0:89cf0851969b 570 float _2q2mx;
AlanHuchin 0:89cf0851969b 571 float _4bx;
AlanHuchin 0:89cf0851969b 572 float _4bz;
AlanHuchin 0:89cf0851969b 573 float _2q1 = 2.0f * q1;
AlanHuchin 0:89cf0851969b 574 float _2q2 = 2.0f * q2;
AlanHuchin 0:89cf0851969b 575 float _2q3 = 2.0f * q3;
AlanHuchin 0:89cf0851969b 576 float _2q4 = 2.0f * q4;
AlanHuchin 0:89cf0851969b 577 float _2q1q3 = 2.0f * q1 * q3;
AlanHuchin 0:89cf0851969b 578 float _2q3q4 = 2.0f * q3 * q4;
AlanHuchin 0:89cf0851969b 579 float q1q1 = q1 * q1;
AlanHuchin 0:89cf0851969b 580 float q1q2 = q1 * q2;
AlanHuchin 0:89cf0851969b 581 float q1q3 = q1 * q3;
AlanHuchin 0:89cf0851969b 582 float q1q4 = q1 * q4;
AlanHuchin 0:89cf0851969b 583 float q2q2 = q2 * q2;
AlanHuchin 0:89cf0851969b 584 float q2q3 = q2 * q3;
AlanHuchin 0:89cf0851969b 585 float q2q4 = q2 * q4;
AlanHuchin 0:89cf0851969b 586 float q3q3 = q3 * q3;
AlanHuchin 0:89cf0851969b 587 float q3q4 = q3 * q4;
AlanHuchin 0:89cf0851969b 588 float q4q4 = q4 * q4;
AlanHuchin 0:89cf0851969b 589
AlanHuchin 0:89cf0851969b 590 // Normalise accelerometer measurement
AlanHuchin 0:89cf0851969b 591 norm = sqrt(ax * ax + ay * ay + az * az);
AlanHuchin 0:89cf0851969b 592 if (norm == 0.0f) return; // handle NaN
AlanHuchin 0:89cf0851969b 593 norm = 1.0f/norm;
AlanHuchin 0:89cf0851969b 594 ax *= norm;
AlanHuchin 0:89cf0851969b 595 ay *= norm;
AlanHuchin 0:89cf0851969b 596 az *= norm;
AlanHuchin 0:89cf0851969b 597
AlanHuchin 0:89cf0851969b 598 // Normalise magnetometer measurement
AlanHuchin 0:89cf0851969b 599 norm = sqrt(mx * mx + my * my + mz * mz);
AlanHuchin 0:89cf0851969b 600 if (norm == 0.0f) return; // handle NaN
AlanHuchin 0:89cf0851969b 601 norm = 1.0f/norm;
AlanHuchin 0:89cf0851969b 602 mx *= norm;
AlanHuchin 0:89cf0851969b 603 my *= norm;
AlanHuchin 0:89cf0851969b 604 mz *= norm;
AlanHuchin 0:89cf0851969b 605
AlanHuchin 0:89cf0851969b 606 // Reference direction of Earth's magnetic field
AlanHuchin 0:89cf0851969b 607 _2q1mx = 2.0f * q1 * mx;
AlanHuchin 0:89cf0851969b 608 _2q1my = 2.0f * q1 * my;
AlanHuchin 0:89cf0851969b 609 _2q1mz = 2.0f * q1 * mz;
AlanHuchin 0:89cf0851969b 610 _2q2mx = 2.0f * q2 * mx;
AlanHuchin 0:89cf0851969b 611 hx = mx * q1q1 - _2q1my * q4 + _2q1mz * q3 + mx * q2q2 + _2q2 * my * q3 + _2q2 * mz * q4 - mx * q3q3 - mx * q4q4;
AlanHuchin 0:89cf0851969b 612 hy = _2q1mx * q4 + my * q1q1 - _2q1mz * q2 + _2q2mx * q3 - my * q2q2 + my * q3q3 + _2q3 * mz * q4 - my * q4q4;
AlanHuchin 0:89cf0851969b 613 _2bx = sqrt(hx * hx + hy * hy);
AlanHuchin 0:89cf0851969b 614 _2bz = -_2q1mx * q3 + _2q1my * q2 + mz * q1q1 + _2q2mx * q4 - mz * q2q2 + _2q3 * my * q4 - mz * q3q3 + mz * q4q4;
AlanHuchin 0:89cf0851969b 615 _4bx = 2.0f * _2bx;
AlanHuchin 0:89cf0851969b 616 _4bz = 2.0f * _2bz;
AlanHuchin 0:89cf0851969b 617
AlanHuchin 0:89cf0851969b 618 // Gradient decent algorithm corrective step
AlanHuchin 0:89cf0851969b 619 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);
AlanHuchin 0:89cf0851969b 620 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);
AlanHuchin 0:89cf0851969b 621 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);
AlanHuchin 0:89cf0851969b 622 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);
AlanHuchin 0:89cf0851969b 623 norm = sqrt(s1 * s1 + s2 * s2 + s3 * s3 + s4 * s4); // normalise step magnitude
AlanHuchin 0:89cf0851969b 624 norm = 1.0f/norm;
AlanHuchin 0:89cf0851969b 625 s1 *= norm;
AlanHuchin 0:89cf0851969b 626 s2 *= norm;
AlanHuchin 0:89cf0851969b 627 s3 *= norm;
AlanHuchin 0:89cf0851969b 628 s4 *= norm;
AlanHuchin 0:89cf0851969b 629
AlanHuchin 0:89cf0851969b 630 // Compute rate of change of quaternion
AlanHuchin 0:89cf0851969b 631 qDot1 = 0.5f * (-q2 * gx - q3 * gy - q4 * gz) - beta * s1;
AlanHuchin 0:89cf0851969b 632 qDot2 = 0.5f * (q1 * gx + q3 * gz - q4 * gy) - beta * s2;
AlanHuchin 0:89cf0851969b 633 qDot3 = 0.5f * (q1 * gy - q2 * gz + q4 * gx) - beta * s3;
AlanHuchin 0:89cf0851969b 634 qDot4 = 0.5f * (q1 * gz + q2 * gy - q3 * gx) - beta * s4;
AlanHuchin 0:89cf0851969b 635
AlanHuchin 0:89cf0851969b 636 // Integrate to yield quaternion
AlanHuchin 0:89cf0851969b 637 q1 += qDot1 * deltat;
AlanHuchin 0:89cf0851969b 638 q2 += qDot2 * deltat;
AlanHuchin 0:89cf0851969b 639 q3 += qDot3 * deltat;
AlanHuchin 0:89cf0851969b 640 q4 += qDot4 * deltat;
AlanHuchin 0:89cf0851969b 641 norm = sqrt(q1 * q1 + q2 * q2 + q3 * q3 + q4 * q4); // normalise quaternion
AlanHuchin 0:89cf0851969b 642 norm = 1.0f/norm;
AlanHuchin 0:89cf0851969b 643 q[0] = q1 * norm;
AlanHuchin 0:89cf0851969b 644 q[1] = q2 * norm;
AlanHuchin 0:89cf0851969b 645 q[2] = q3 * norm;
AlanHuchin 0:89cf0851969b 646 q[3] = q4 * norm;
AlanHuchin 0:89cf0851969b 647
AlanHuchin 0:89cf0851969b 648 }
AlanHuchin 0:89cf0851969b 649
AlanHuchin 0:89cf0851969b 650 // Similar to Madgwick scheme but uses proportional and integral filtering on the error between estimated reference vectors and
AlanHuchin 0:89cf0851969b 651 // measured ones.
AlanHuchin 0:89cf0851969b 652 void MPU9250::MahonyQuaternionUpdate(float ax, float ay, float az, float gx, float gy, float gz, float mx, float my, float mz)
AlanHuchin 0:89cf0851969b 653 {
AlanHuchin 0:89cf0851969b 654 float q1 = q[0], q2 = q[1], q3 = q[2], q4 = q[3]; // short name local variable for readability
AlanHuchin 0:89cf0851969b 655 float norm;
AlanHuchin 0:89cf0851969b 656 float hx, hy, bx, bz;
AlanHuchin 0:89cf0851969b 657 float vx, vy, vz, wx, wy, wz;
AlanHuchin 0:89cf0851969b 658 float ex, ey, ez;
AlanHuchin 0:89cf0851969b 659 float pa, pb, pc;
AlanHuchin 0:89cf0851969b 660
AlanHuchin 0:89cf0851969b 661 // Auxiliary variables to avoid repeated arithmetic
AlanHuchin 0:89cf0851969b 662 float q1q1 = q1 * q1;
AlanHuchin 0:89cf0851969b 663 float q1q2 = q1 * q2;
AlanHuchin 0:89cf0851969b 664 float q1q3 = q1 * q3;
AlanHuchin 0:89cf0851969b 665 float q1q4 = q1 * q4;
AlanHuchin 0:89cf0851969b 666 float q2q2 = q2 * q2;
AlanHuchin 0:89cf0851969b 667 float q2q3 = q2 * q3;
AlanHuchin 0:89cf0851969b 668 float q2q4 = q2 * q4;
AlanHuchin 0:89cf0851969b 669 float q3q3 = q3 * q3;
AlanHuchin 0:89cf0851969b 670 float q3q4 = q3 * q4;
AlanHuchin 0:89cf0851969b 671 float q4q4 = q4 * q4;
AlanHuchin 0:89cf0851969b 672
AlanHuchin 0:89cf0851969b 673 // Normalise accelerometer measurement
AlanHuchin 0:89cf0851969b 674 norm = sqrt(ax * ax + ay * ay + az * az);
AlanHuchin 0:89cf0851969b 675 if (norm == 0.0f) return; // handle NaN
AlanHuchin 0:89cf0851969b 676 norm = 1.0f / norm; // use reciprocal for division
AlanHuchin 0:89cf0851969b 677 ax *= norm;
AlanHuchin 0:89cf0851969b 678 ay *= norm;
AlanHuchin 0:89cf0851969b 679 az *= norm;
AlanHuchin 0:89cf0851969b 680
AlanHuchin 0:89cf0851969b 681 // Normalise magnetometer measurement
AlanHuchin 0:89cf0851969b 682 norm = sqrt(mx * mx + my * my + mz * mz);
AlanHuchin 0:89cf0851969b 683 if (norm == 0.0f) return; // handle NaN
AlanHuchin 0:89cf0851969b 684 norm = 1.0f / norm; // use reciprocal for division
AlanHuchin 0:89cf0851969b 685 mx *= norm;
AlanHuchin 0:89cf0851969b 686 my *= norm;
AlanHuchin 0:89cf0851969b 687 mz *= norm;
AlanHuchin 0:89cf0851969b 688
AlanHuchin 0:89cf0851969b 689 // Reference direction of Earth's magnetic field
AlanHuchin 0:89cf0851969b 690 hx = 2.0f * mx * (0.5f - q3q3 - q4q4) + 2.0f * my * (q2q3 - q1q4) + 2.0f * mz * (q2q4 + q1q3);
AlanHuchin 0:89cf0851969b 691 hy = 2.0f * mx * (q2q3 + q1q4) + 2.0f * my * (0.5f - q2q2 - q4q4) + 2.0f * mz * (q3q4 - q1q2);
AlanHuchin 0:89cf0851969b 692 bx = sqrt((hx * hx) + (hy * hy));
AlanHuchin 0:89cf0851969b 693 bz = 2.0f * mx * (q2q4 - q1q3) + 2.0f * my * (q3q4 + q1q2) + 2.0f * mz * (0.5f - q2q2 - q3q3);
AlanHuchin 0:89cf0851969b 694
AlanHuchin 0:89cf0851969b 695 // Estimated direction of gravity and magnetic field
AlanHuchin 0:89cf0851969b 696 vx = 2.0f * (q2q4 - q1q3);
AlanHuchin 0:89cf0851969b 697 vy = 2.0f * (q1q2 + q3q4);
AlanHuchin 0:89cf0851969b 698 vz = q1q1 - q2q2 - q3q3 + q4q4;
AlanHuchin 0:89cf0851969b 699 wx = 2.0f * bx * (0.5f - q3q3 - q4q4) + 2.0f * bz * (q2q4 - q1q3);
AlanHuchin 0:89cf0851969b 700 wy = 2.0f * bx * (q2q3 - q1q4) + 2.0f * bz * (q1q2 + q3q4);
AlanHuchin 0:89cf0851969b 701 wz = 2.0f * bx * (q1q3 + q2q4) + 2.0f * bz * (0.5f - q2q2 - q3q3);
AlanHuchin 0:89cf0851969b 702
AlanHuchin 0:89cf0851969b 703 // Error is cross product between estimated direction and measured direction of gravity
AlanHuchin 0:89cf0851969b 704 ex = (ay * vz - az * vy) + (my * wz - mz * wy);
AlanHuchin 0:89cf0851969b 705 ey = (az * vx - ax * vz) + (mz * wx - mx * wz);
AlanHuchin 0:89cf0851969b 706 ez = (ax * vy - ay * vx) + (mx * wy - my * wx);
AlanHuchin 0:89cf0851969b 707 if (Ki > 0.0f)
AlanHuchin 0:89cf0851969b 708 {
AlanHuchin 0:89cf0851969b 709 eInt[0] += ex; // accumulate integral error
AlanHuchin 0:89cf0851969b 710 eInt[1] += ey;
AlanHuchin 0:89cf0851969b 711 eInt[2] += ez;
AlanHuchin 0:89cf0851969b 712 }
AlanHuchin 0:89cf0851969b 713 else
AlanHuchin 0:89cf0851969b 714 {
AlanHuchin 0:89cf0851969b 715 eInt[0] = 0.0f; // prevent integral wind up
AlanHuchin 0:89cf0851969b 716 eInt[1] = 0.0f;
AlanHuchin 0:89cf0851969b 717 eInt[2] = 0.0f;
AlanHuchin 0:89cf0851969b 718 }
AlanHuchin 0:89cf0851969b 719
AlanHuchin 0:89cf0851969b 720 // Apply feedback terms
AlanHuchin 0:89cf0851969b 721 gx = gx + Kp * ex + Ki * eInt[0];
AlanHuchin 0:89cf0851969b 722 gy = gy + Kp * ey + Ki * eInt[1];
AlanHuchin 0:89cf0851969b 723 gz = gz + Kp * ez + Ki * eInt[2];
AlanHuchin 0:89cf0851969b 724
AlanHuchin 0:89cf0851969b 725 // Integrate rate of change of quaternion
AlanHuchin 0:89cf0851969b 726 pa = q2;
AlanHuchin 0:89cf0851969b 727 pb = q3;
AlanHuchin 0:89cf0851969b 728 pc = q4;
AlanHuchin 0:89cf0851969b 729 q1 = q1 + (-q2 * gx - q3 * gy - q4 * gz) * (0.5f * deltat);
AlanHuchin 0:89cf0851969b 730 q2 = pa + (q1 * gx + pb * gz - pc * gy) * (0.5f * deltat);
AlanHuchin 0:89cf0851969b 731 q3 = pb + (q1 * gy - pa * gz + pc * gx) * (0.5f * deltat);
AlanHuchin 0:89cf0851969b 732 q4 = pc + (q1 * gz + pa * gy - pb * gx) * (0.5f * deltat);
AlanHuchin 0:89cf0851969b 733
AlanHuchin 0:89cf0851969b 734 // Normalise quaternion
AlanHuchin 0:89cf0851969b 735 norm = sqrt(q1 * q1 + q2 * q2 + q3 * q3 + q4 * q4);
AlanHuchin 0:89cf0851969b 736 norm = 1.0f / norm;
AlanHuchin 0:89cf0851969b 737 q[0] = q1 * norm;
AlanHuchin 0:89cf0851969b 738 q[1] = q2 * norm;
AlanHuchin 0:89cf0851969b 739 q[2] = q3 * norm;
AlanHuchin 0:89cf0851969b 740 q[3] = q4 * norm;
AlanHuchin 0:89cf0851969b 741
AlanHuchin 0:89cf0851969b 742 }
AlanHuchin 0:89cf0851969b 743