Class of MPU9250
Dependencies: AHRS_fillter mbed
Fork of MPU9250AHRS by
Diff: MPU9250.cpp
- Revision:
- 9:a9b0f8540cc6
- Parent:
- 8:928673148b55
--- a/MPU9250.cpp Wed Jan 20 02:42:22 2016 +0000 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000 @@ -1,699 +0,0 @@ -#include "MPU9250.h" - - -MPU9250::MPU9250(PinName sda, PinName scl, PinName tx, PinName rx, int address) : i2c(sda, scl), pc(tx,rx) -{ - if(address == 0) - MPU9250_ADDRESS = MPU9250_ADDRESS_68; - else if(address == 1) MPU9250_ADDRESS = MPU9250_ADDRESS_69; - else { - printf("Wrong Address\n"); - while(1); - } - - i2c.frequency(400000); - - for(int i=0; i<=3; i++) { - magCalibration[i] = 0; - magbias[i] = 0; - gyroBias[i] = 0; - accelBias[i] = 0; - } - Mmode = 0x06; // Either 8 Hz 0x02) or 100 Hz (0x06) magnetometer data ODR -} - -void MPU9250::Start() -{ - whoami = readByte(MPU9250_ADDRESS, WHO_AM_I_MPU9250); // Read WHO_AM_I register for MPU-9250 - pc.printf("I AM 0x%x\n\r", whoami); - pc.printf("I SHOULD BE 0x71\n\r"); - - if (whoami == 0x71) { // WHO_AM_I should always be 0x68 - pc.printf("MPU9250 WHO_AM_I is 0x%x\n\r", whoami); - pc.printf("MPU9250 is online...\n\r"); - wait(1); - - resetMPU9250(); // Reset registers to default in preparation for device calibration - MPU9250SelfTest(); // Start by performing self test and reporting values - /*pc.printf("x-axis self test: acceleration trim within : %f % of factory value\n\r", SelfTest[0]); - pc.printf("y-axis self test: acceleration trim within : %f % of factory value\n\r", SelfTest[1]); - pc.printf("z-axis self test: acceleration trim within : %f % of factory value\n\r", SelfTest[2]); - pc.printf("x-axis self test: gyration trim within : %f % of factory value\n\r", SelfTest[3]); - pc.printf("y-axis self test: gyration trim within : %f % of factory value\n\r", SelfTest[4]); - pc.printf("z-axis self test: gyration trim within : %f % of factory value\n\r", SelfTest[5]);*/ - calibrateMPU9250(); // Calibrate gyro and accelerometers, load biases in bias registers - /*pc.printf("x gyro bias = %f\n\r", gyroBias[0]); - pc.printf("y gyro bias = %f\n\r", gyroBias[1]); - pc.printf("z gyro bias = %f\n\r", gyroBias[2]); - pc.printf("x accel bias = %f\n\r", accelBias[0]); - pc.printf("y accel bias = %f\n\r", accelBias[1]); - pc.printf("z accel bias = %f\n\r", accelBias[2]);*/ - wait(2); - initMPU9250(); - pc.printf("MPU9250 initialized for active data mode....\n\r"); // Initialize device for active mode read of acclerometer, gyroscope, and temperature - initAK8963(); - pc.printf("AK8963 initialized for active data mode....\n\r"); // Initialize device for active mode read of magnetometer - - whoami = readByte(AK8963_ADDRESS, WHO_AM_I_AK8963); // Read WHO_AM_I register for MPU-9250 - pc.printf("I AM 0x%x\n\r", whoami); - pc.printf("I SHOULD BE 0x48\n\r"); - if(whoami != 0x48) { - while(1); - } - /*pc.printf("Accelerometer full-scale range = %f g\n\r", 2.0f*(float)(1<<Ascale)); - pc.printf("Gyroscope full-scale range = %f deg/s\n\r", 250.0f*(float)(1<<Gscale)); - if(Mscale == 0) pc.printf("Magnetometer resolution = 14 bits\n\r"); - if(Mscale == 1) pc.printf("Magnetometer resolution = 16 bits\n\r"); - if(Mmode == 2) pc.printf("Magnetometer ODR = 8 Hz\n\r"); - if(Mmode == 6) pc.printf("Magnetometer ODR = 100 Hz\n\r");*/ - wait(1); - } else { - pc.printf("Could not connect to MPU9250: \n\r"); - pc.printf("%#x \n", whoami); - - while(1) ; // Loop forever if communication doesn't happen - } - - - getAres(); // Get accelerometer sensitivity - getGres(); // Get gyro sensitivity - getMres(); // Get magnetometer sensitivity - /*pc.printf("Accelerometer sensitivity is %f LSB/g \n\r", 1.0f/aRes); - pc.printf("Gyroscope sensitivity is %f LSB/deg/s \n\r", 1.0f/gRes); - pc.printf("Magnetometer sensitivity is %f LSB/G \n\r", 1.0f/mRes);*/ - - MagCal(); -} - -void MPU9250::ReadRawAccGyroMag() -{ - // If intPin goes high, all data registers have new data - if(readByte(MPU9250_ADDRESS, INT_STATUS) & 0x01) { // On interrupt, check if data ready interrupt - - readAccelData(); // Read the x/y/z adc values - AccelXYZCal(); - // Now we'll calculate the accleration value into actual g's - /*ax = (float)accelCount[0]*aRes - accelBias[0]; // get actual g value, this depends on scale being set - ay = (float)accelCount[1]*aRes - accelBias[1]; - az = (float)accelCount[2]*aRes - accelBias[2];*/ - - readGyroData(); // Read the x/y/z adc values - GyroXYZCal(); - // Calculate the gyro value into actual degrees per second - /*gx = (float)gyroCount[0]*gRes - gyroBias[0]; // get actual gyro value, this depends on scale being set - gy = (float)gyroCount[1]*gRes - gyroBias[1]; - gz = (float)gyroCount[2]*gRes - gyroBias[2];*/ - - readMagData(); // Read the x/y/z adc values - MagXYZCal(); - /*mx = ((float)magCount[0]-xmin)*magCalibration[0] + magbias[0]; // get actual magnetometer value, this depends on scale being set - my = ((float)magCount[1]-ymin)*magCalibration[1] + magbias[1]; - mz = ((float)magCount[2]-zmin)*magCalibration[2] + magbias[2];*/ - } -} - -void MPU9250::writeByte(uint8_t address, uint8_t subAddress, uint8_t data) -{ - char data_write[2]; - data_write[0] = subAddress; - data_write[1] = data; - i2c.write(address, data_write, 2, 0); -} - -char MPU9250::readByte(uint8_t address, uint8_t subAddress) -{ - char data[1]; // `data` will store the register data - char data_write[1]; - data_write[0] = subAddress; - i2c.write(address, data_write, 1, 1); // no stop - i2c.read(address, data, 1, 0); - return data[0]; -} - -void MPU9250::readBytes(uint8_t address, uint8_t subAddress, uint8_t count, uint8_t * dest) -{ - char data[14]; - char data_write[1]; - data_write[0] = subAddress; - i2c.write(address, data_write, 1, 1); // no stop - i2c.read(address, data, count, 0); - for(int ii = 0; ii < count; ii++) { - dest[ii] = data[ii]; - } -} - - -void MPU9250::setMres() -{ - getMres(); - switch (Mscale) { - // Possible magnetometer scales (and their register bit settings) are: - // 14 bit resolution (0) and 16 bit resolution (1) - case MFS_14BITS: - mRes = 10.0*4219.0/8190.0; // Proper scale to return milliGauss - break; - case MFS_16BITS: - mRes = 10.0*4219.0/32760.0; // Proper scale to return milliGauss - break; - } -} - - -void MPU9250::setGres() -{ - getGres(); - switch (Gscale) { - // Possible gyro scales (and their register bit settings) are: - // 250 DPS (00), 500 DPS (01), 1000 DPS (10), and 2000 DPS (11). - // Here's a bit of an algorith to calculate DPS/(ADC tick) based on that 2-bit value: - case GFS_250DPS: - gRes = 250.0/32768.0; - break; - case GFS_500DPS: - gRes = 500.0/32768.0; - break; - case GFS_1000DPS: - gRes = 1000.0/32768.0; - break; - case GFS_2000DPS: - gRes = 2000.0/32768.0; - break; - } -} - -void MPU9250::setAres() -{ - getAres(); - switch (Ascale) { - // Possible accelerometer scales (and their register bit settings) are: - // 2 Gs (00), 4 Gs (01), 8 Gs (10), and 16 Gs (11). - // Here's a bit of an algorith to calculate DPS/(ADC tick) based on that 2-bit value: - case AFS_2G: - aRes = 2.0/32768.0; - break; - case AFS_4G: - aRes = 4.0/32768.0; - break; - case AFS_8G: - aRes = 8.0/32768.0; - break; - case AFS_16G: - aRes = 16.0/32768.0; - break; - } -} - -void MPU9250::getMres() -{ - Mscale = MFS_16BITS; // MFS_14BITS or MFS_16BITS, 14-bit or 16-bit magnetometer resolution -} - - -void MPU9250::getGres() -{ - Gscale = GFS_250DPS; // GFS_250DPS, GFS_500DPS, GFS_1000DPS, GFS_2000DPS -} - -void MPU9250::getAres() -{ - Ascale = AFS_2G; // AFS_2G, AFS_4G, AFS_8G, AFS_16G -} - -void MPU9250::MagCal() -{ - printf("START scan mag\n\r\n\r\n\r"); - - //Assign random value before calibrate - /*xmax = -4914.0f; - xmin = 4914.0f; - - ymax = -4914.0; - ymin = 4914.0f; - - zmax = -4914.0; - zmin = 4914.0f; - - change=false; - - while(1) { - readMagData(magCount); - - if(magCount[0]<xmin) { - xmin = magCount[0]; - change = true; - } - if(magCount[0]>xmax) { - xmax = magCount[0]; - change = true; - } - - if(magCount[1]<ymin) { - ymin = magCount[1]; - change = true; - } - if(magCount[1]>ymax) { - ymax = magCount[1]; - change = true; - } - - - if(magCount[2]<zmin) { - zmin = magCount[2]; - change = true; - } - if(magCount[2]>zmax) { - zmax = magCount[2]; - change = true; - } - - if(change==true) { - printf("Mx Max= %f Min= %f\n\r",xmax,xmin); - printf("My Max= %f Min= %f\n\r",ymax,ymin); - printf("Mz Max= %f Min= %f\n\r",zmax,zmin); - change=false; - }*/ - - //Out of Calibration loop - /*if(button==1) { - while(button==1); - break; - }*/ - //} - - - xmax = 188.000000; - xmin = -316.000000; - ymax = 485.000000; - ymin = -26.000000; - zmax = 165.000000; - xmin = -230.000000; - - magbias[0] = -1.0; - magbias[1] = -1.0; - magbias[2] = -1.0; - - magCalibration[0] = 2.0f / (xmax -xmin); - magCalibration[1] = 2.0f / (ymax -ymin); - magCalibration[2] = 2.0f / (zmax -zmin); - - printf("mag[0] %f",magbias[0]); - printf("mag[1] %f",magbias[1]); - printf("mag[2] %f\n\r",magbias[2]); -} - -void MPU9250::AccelXYZCal() -{ - ax = (float)accelCount[0]*aRes - accelBias[0]; // get actual g value, this depends on scale being set - ay = (float)accelCount[1]*aRes - accelBias[1]; - az = (float)accelCount[2]*aRes - accelBias[2]; -} - -void MPU9250::GyroXYZCal() -{ - gx = (float)gyroCount[0]*gRes - gyroBias[0]; // get actual gyro value, this depends on scale being set - gy = (float)gyroCount[1]*gRes - gyroBias[1]; - gz = (float)gyroCount[2]*gRes - gyroBias[2]; -} - -void MPU9250::MagXYZCal() -{ - mx = ((float)magCount[0]-xmin)*magCalibration[0] + magbias[0]; // get actual magnetometer value, this depends on scale being set - my = ((float)magCount[1]-ymin)*magCalibration[1] + magbias[1]; - mz = ((float)magCount[2]-zmin)*magCalibration[2] + magbias[2]; -} - - -void MPU9250::readAccelData() -{ - float destination[3] = {0,0,0}; - uint8_t rawData[6]; // x/y/z accel register data stored here - readBytes(MPU9250_ADDRESS, ACCEL_XOUT_H, 6, &rawData[0]); // Read the six raw data registers into data array - destination[0] = (int16_t)(((int16_t)rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value - destination[1] = (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ; - destination[2] = (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ; - - for(int i=0; i<=2; i++) - accelCount[i] = (float)destination[i]; -} - -void MPU9250::readGyroData() -{ - float destination[3] = {0,0,0}; - uint8_t rawData[6]; // x/y/z gyro register data stored here - readBytes(MPU9250_ADDRESS, GYRO_XOUT_H, 6, &rawData[0]); // Read the six raw data registers sequentially into data array - destination[0] = (int16_t)(((int16_t)rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value - destination[1] = (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ; - destination[2] = (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ; - - for(int i=0; i<=2; i++) - gyroCount[i] = (float)destination[i]; -} - -void MPU9250::readMagData() -{ - float destination[3] = {0,0,0}; - uint8_t rawData[7]; // x/y/z gyro register data, ST2 register stored here, must read ST2 at end of data acquisition - if(readByte(AK8963_ADDRESS, AK8963_ST1) & 0x01) { // wait for magnetometer data ready bit to be set - readBytes(AK8963_ADDRESS, AK8963_XOUT_L, 7, &rawData[0]); // Read the six raw data and ST2 registers sequentially into data array - uint8_t c = rawData[6]; // End data read by reading ST2 register - if(!(c & 0x08)) { // Check if magnetic sensor overflow set, if not then report data - destination[0] = (int16_t)(((int16_t)rawData[1] << 8) | rawData[0]); // Turn the MSB and LSB into a signed 16-bit value - destination[1] = (int16_t)(((int16_t)rawData[3] << 8) | rawData[2]) ; // Data stored as little Endian - destination[2] = (int16_t)(((int16_t)rawData[5] << 8) | rawData[4]) ; - } - } - - for(int i=0; i<=2; i++) - magCount[i] = (float)destination[i]; -} - -void MPU9250::readTempData() -{ - int16_t destination; - uint8_t rawData[2]; // x/y/z gyro register data stored here - readBytes(MPU9250_ADDRESS, TEMP_OUT_H, 2, &rawData[0]); // Read the two raw data registers sequentially into data array - destination = (int16_t)(((int16_t)rawData[0]) << 8 | rawData[1]) ; // Turn the MSB and LSB into a 16-bit value - destination = ((float) destination) / 333.87f + 21.0f; - temperature = destination; -} - - -void MPU9250::resetMPU9250() -{ - // reset device - writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x80); // Write a one to bit 7 reset bit; toggle reset device - wait(0.1); -} - -void MPU9250::initAK8963() -{ - float destination[3] = {0,0,0}; - // First extract the factory calibration for each magnetometer axis - uint8_t rawData[3]; // x/y/z gyro calibration data stored here - writeByte(AK8963_ADDRESS, AK8963_CNTL, 0x00); // Power down magnetometer - wait(0.01); - writeByte(AK8963_ADDRESS, AK8963_CNTL, 0x0F); // Enter Fuse ROM access mode - wait(0.01); - readBytes(AK8963_ADDRESS, AK8963_ASAX, 3, &rawData[0]); // Read the x-, y-, and z-axis calibration values - destination[0] = (float)(rawData[0] - 128)/256.0f + 1.0f; // Return x-axis sensitivity adjustment values, etc. - destination[1] = (float)(rawData[1] - 128)/256.0f + 1.0f; - destination[2] = (float)(rawData[2] - 128)/256.0f + 1.0f; - writeByte(AK8963_ADDRESS, AK8963_CNTL, 0x00); // Power down magnetometer - wait(0.01); - // Configure the magnetometer for continuous read and highest resolution - // set Mscale bit 4 to 1 (0) to enable 16 (14) bit resolution in CNTL register, - // and enable continuous mode data acquisition Mmode (bits [3:0]), 0010 for 8 Hz and 0110 for 100 Hz sample rates - writeByte(AK8963_ADDRESS, AK8963_CNTL, Mscale << 4 | Mmode); // Set magnetometer data resolution and sample ODR - wait(0.01); - - for(int i=0; i<=2; i++) - magCalibration[i] = destination[i]; -} - - -void MPU9250::initMPU9250() -{ -// Initialize MPU9250 device -// wake up device - writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x00); // Clear sleep mode bit (6), enable all sensors - wait(0.1); // Delay 100 ms for PLL to get established on x-axis gyro; should check for PLL ready interrupt - -// get stable time source - writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x01); // Set clock source to be PLL with x-axis gyroscope reference, bits 2:0 = 001 - -// Configure Gyro and Accelerometer -// Disable FSYNC and set accelerometer and gyro bandwidth to 44 and 42 Hz, respectively; -// DLPF_CFG = bits 2:0 = 010; this sets the sample rate at 1 kHz for both -// Maximum delay is 4.9 ms which is just over a 200 Hz maximum rate - writeByte(MPU9250_ADDRESS, CONFIG, 0x03); - -// Set sample rate = gyroscope output rate/(1 + SMPLRT_DIV) - writeByte(MPU9250_ADDRESS, SMPLRT_DIV, 0x04); // Use a 200 Hz rate; the same rate set in CONFIG above - -// Set gyroscope full scale range -// Range selects FS_SEL and AFS_SEL are 0 - 3, so 2-bit values are left-shifted into positions 4:3 - uint8_t c = readByte(MPU9250_ADDRESS, GYRO_CONFIG); - writeByte(MPU9250_ADDRESS, GYRO_CONFIG, c & ~0xE0); // Clear self-test bits [7:5] - writeByte(MPU9250_ADDRESS, GYRO_CONFIG, c & ~0x18); // Clear AFS bits [4:3] - writeByte(MPU9250_ADDRESS, GYRO_CONFIG, c | Gscale << 3); // Set full scale range for the gyro - -// Set accelerometer configuration - c = readByte(MPU9250_ADDRESS, ACCEL_CONFIG); - writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, c & ~0xE0); // Clear self-test bits [7:5] - writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, c & ~0x18); // Clear AFS bits [4:3] - writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, c | Ascale << 3); // Set full scale range for the accelerometer - -// Set accelerometer sample rate configuration -// It is possible to get a 4 kHz sample rate from the accelerometer by choosing 1 for -// accel_fchoice_b bit [3]; in this case the bandwidth is 1.13 kHz - c = readByte(MPU9250_ADDRESS, ACCEL_CONFIG2); - writeByte(MPU9250_ADDRESS, ACCEL_CONFIG2, c & ~0x0F); // Clear accel_fchoice_b (bit 3) and A_DLPFG (bits [2:0]) - writeByte(MPU9250_ADDRESS, ACCEL_CONFIG2, c | 0x03); // Set accelerometer rate to 1 kHz and bandwidth to 41 Hz - -// The accelerometer, gyro, and thermometer are set to 1 kHz sample rates, -// but all these rates are further reduced by a factor of 5 to 200 Hz because of the SMPLRT_DIV setting - - // Configure Interrupts and Bypass Enable - // Set interrupt pin active high, push-pull, and clear on read of INT_STATUS, enable I2C_BYPASS_EN so additional chips - // can join the I2C bus and all can be controlled by the Arduino as master - writeByte(MPU9250_ADDRESS, INT_PIN_CFG, 0x22); - writeByte(MPU9250_ADDRESS, INT_ENABLE, 0x01); // Enable data ready (bit 0) interrupt -} - -// Function which accumulates gyro and accelerometer data after device initialization. It calculates the average -// of the at-rest readings and then loads the resulting offsets into accelerometer and gyro bias registers. -void MPU9250::calibrateMPU9250() -{ - uint8_t data[12]; // data array to hold accelerometer and gyro x, y, z, data - uint16_t ii, packet_count, fifo_count; - int32_t gyro_bias[3] = {0, 0, 0}, accel_bias[3] = {0, 0, 0}; - -// reset device, reset all registers, clear gyro and accelerometer bias registers - writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x80); // Write a one to bit 7 reset bit; toggle reset device - wait(0.1); - -// get stable time source -// Set clock source to be PLL with x-axis gyroscope reference, bits 2:0 = 001 - writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x01); - writeByte(MPU9250_ADDRESS, PWR_MGMT_2, 0x00); - wait(0.2); - -// Configure device for bias calculation - writeByte(MPU9250_ADDRESS, INT_ENABLE, 0x00); // Disable all interrupts - writeByte(MPU9250_ADDRESS, FIFO_EN, 0x00); // Disable FIFO - writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x00); // Turn on internal clock source - writeByte(MPU9250_ADDRESS, I2C_MST_CTRL, 0x00); // Disable I2C master - writeByte(MPU9250_ADDRESS, USER_CTRL, 0x00); // Disable FIFO and I2C master modes - writeByte(MPU9250_ADDRESS, USER_CTRL, 0x0C); // Reset FIFO and DMP - wait(0.015); - -// Configure MPU9250 gyro and accelerometer for bias calculation - writeByte(MPU9250_ADDRESS, CONFIG, 0x01); // Set low-pass filter to 188 Hz - writeByte(MPU9250_ADDRESS, SMPLRT_DIV, 0x00); // Set sample rate to 1 kHz - writeByte(MPU9250_ADDRESS, GYRO_CONFIG, 0x00); // Set gyro full-scale to 250 degrees per second, maximum sensitivity - writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, 0x00); // Set accelerometer full-scale to 2 g, maximum sensitivity - - uint16_t gyrosensitivity = 131; // = 131 LSB/degrees/sec - uint16_t accelsensitivity = 16384; // = 16384 LSB/g - -// Configure FIFO to capture accelerometer and gyro data for bias calculation - writeByte(MPU9250_ADDRESS, USER_CTRL, 0x40); // Enable FIFO - writeByte(MPU9250_ADDRESS, FIFO_EN, 0x78); // Enable gyro and accelerometer sensors for FIFO (max size 512 bytes in MPU-9250) - wait(0.04); // accumulate 40 samples in 80 milliseconds = 480 bytes - -// At end of sample accumulation, turn off FIFO sensor read - writeByte(MPU9250_ADDRESS, FIFO_EN, 0x00); // Disable gyro and accelerometer sensors for FIFO - readBytes(MPU9250_ADDRESS, FIFO_COUNTH, 2, &data[0]); // read FIFO sample count - fifo_count = ((uint16_t)data[0] << 8) | data[1]; - packet_count = fifo_count/12;// How many sets of full gyro and accelerometer data for averaging - - for (ii = 0; ii < packet_count; ii++) { - int16_t accel_temp[3] = {0, 0, 0}, gyro_temp[3] = {0, 0, 0}; - readBytes(MPU9250_ADDRESS, FIFO_R_W, 12, &data[0]); // read data for averaging - accel_temp[0] = (int16_t) (((int16_t)data[0] << 8) | data[1] ) ; // Form signed 16-bit integer for each sample in FIFO - accel_temp[1] = (int16_t) (((int16_t)data[2] << 8) | data[3] ) ; - accel_temp[2] = (int16_t) (((int16_t)data[4] << 8) | data[5] ) ; - gyro_temp[0] = (int16_t) (((int16_t)data[6] << 8) | data[7] ) ; - gyro_temp[1] = (int16_t) (((int16_t)data[8] << 8) | data[9] ) ; - gyro_temp[2] = (int16_t) (((int16_t)data[10] << 8) | data[11]) ; - - accel_bias[0] += (int32_t) accel_temp[0]; // Sum individual signed 16-bit biases to get accumulated signed 32-bit biases - accel_bias[1] += (int32_t) accel_temp[1]; - accel_bias[2] += (int32_t) accel_temp[2]; - gyro_bias[0] += (int32_t) gyro_temp[0]; - gyro_bias[1] += (int32_t) gyro_temp[1]; - gyro_bias[2] += (int32_t) gyro_temp[2]; - - } - accel_bias[0] /= (int32_t) packet_count; // Normalize sums to get average count biases - accel_bias[1] /= (int32_t) packet_count; - accel_bias[2] /= (int32_t) packet_count; - gyro_bias[0] /= (int32_t) packet_count; - gyro_bias[1] /= (int32_t) packet_count; - gyro_bias[2] /= (int32_t) packet_count; - - if(accel_bias[2] > 0L) { - accel_bias[2] -= (int32_t) accelsensitivity; // Remove gravity from the z-axis accelerometer bias calculation - } else { - accel_bias[2] += (int32_t) accelsensitivity; - } - -// Construct the gyro biases for push to the hardware gyro bias registers, which are reset to zero upon device startup - 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 - data[1] = (-gyro_bias[0]/4) & 0xFF; // Biases are additive, so change sign on calculated average gyro biases - data[2] = (-gyro_bias[1]/4 >> 8) & 0xFF; - data[3] = (-gyro_bias[1]/4) & 0xFF; - data[4] = (-gyro_bias[2]/4 >> 8) & 0xFF; - data[5] = (-gyro_bias[2]/4) & 0xFF; - -/// Push gyro biases to hardware registers - /* writeByte(MPU9250_ADDRESS, XG_OFFSET_H, data[0]); - writeByte(MPU9250_ADDRESS, XG_OFFSET_L, data[1]); - writeByte(MPU9250_ADDRESS, YG_OFFSET_H, data[2]); - writeByte(MPU9250_ADDRESS, YG_OFFSET_L, data[3]); - writeByte(MPU9250_ADDRESS, ZG_OFFSET_H, data[4]); - writeByte(MPU9250_ADDRESS, ZG_OFFSET_L, data[5]); - */ - gyroBias[0] = (float) gyro_bias[0]/(float) gyrosensitivity; // construct gyro bias in deg/s for later manual subtraction - gyroBias[1] = (float) gyro_bias[1]/(float) gyrosensitivity; - gyroBias[2] = (float) gyro_bias[2]/(float) gyrosensitivity; - -// Construct the accelerometer biases for push to the hardware accelerometer bias registers. These registers contain -// factory trim values which must be added to the calculated accelerometer biases; on boot up these registers will hold -// non-zero values. In addition, bit 0 of the lower byte must be preserved since it is used for temperature -// compensation calculations. Accelerometer bias registers expect bias input as 2048 LSB per g, so that -// the accelerometer biases calculated above must be divided by 8. - - int32_t accel_bias_reg[3] = {0, 0, 0}; // A place to hold the factory accelerometer trim biases - readBytes(MPU9250_ADDRESS, XA_OFFSET_H, 2, &data[0]); // Read factory accelerometer trim values - accel_bias_reg[0] = (int16_t) ((int16_t)data[0] << 8) | data[1]; - readBytes(MPU9250_ADDRESS, YA_OFFSET_H, 2, &data[0]); - accel_bias_reg[1] = (int16_t) ((int16_t)data[0] << 8) | data[1]; - readBytes(MPU9250_ADDRESS, ZA_OFFSET_H, 2, &data[0]); - accel_bias_reg[2] = (int16_t) ((int16_t)data[0] << 8) | data[1]; - - uint32_t mask = 1uL; // Define mask for temperature compensation bit 0 of lower byte of accelerometer bias registers - uint8_t mask_bit[3] = {0, 0, 0}; // Define array to hold mask bit for each accelerometer bias axis - - for(ii = 0; ii < 3; ii++) { - if(accel_bias_reg[ii] & mask) mask_bit[ii] = 0x01; // If temperature compensation bit is set, record that fact in mask_bit - } - - // Construct total accelerometer bias, including calculated average accelerometer bias from above - accel_bias_reg[0] -= (accel_bias[0]/8); // Subtract calculated averaged accelerometer bias scaled to 2048 LSB/g (16 g full scale) - accel_bias_reg[1] -= (accel_bias[1]/8); - accel_bias_reg[2] -= (accel_bias[2]/8); - - data[0] = (accel_bias_reg[0] >> 8) & 0xFF; - data[1] = (accel_bias_reg[0]) & 0xFF; - data[1] = data[1] | mask_bit[0]; // preserve temperature compensation bit when writing back to accelerometer bias registers - data[2] = (accel_bias_reg[1] >> 8) & 0xFF; - data[3] = (accel_bias_reg[1]) & 0xFF; - data[3] = data[3] | mask_bit[1]; // preserve temperature compensation bit when writing back to accelerometer bias registers - data[4] = (accel_bias_reg[2] >> 8) & 0xFF; - data[5] = (accel_bias_reg[2]) & 0xFF; - data[5] = data[5] | mask_bit[2]; // preserve temperature compensation bit when writing back to accelerometer bias registers - -// Apparently this is not working for the acceleration biases in the MPU-9250 -// Are we handling the temperature correction bit properly? -// Push accelerometer biases to hardware registers - /* writeByte(MPU9250_ADDRESS, XA_OFFSET_H, data[0]); - writeByte(MPU9250_ADDRESS, XA_OFFSET_L, data[1]); - writeByte(MPU9250_ADDRESS, YA_OFFSET_H, data[2]); - writeByte(MPU9250_ADDRESS, YA_OFFSET_L, data[3]); - writeByte(MPU9250_ADDRESS, ZA_OFFSET_H, data[4]); - writeByte(MPU9250_ADDRESS, ZA_OFFSET_L, data[5]); - */ -// Output scaled accelerometer biases for manual subtraction in the main program - accelBias[0] = (float)accel_bias[0]/(float)accelsensitivity; - accelBias[1] = (float)accel_bias[1]/(float)accelsensitivity; - accelBias[2] = (float)accel_bias[2]/(float)accelsensitivity; -} - - -// Accelerometer and gyroscope self test; check calibration wrt factory settings -void MPU9250::MPU9250SelfTest() // Should return percent deviation from factory trim values, +/- 14 or less deviation is a pass -{ - //float destination[6] = {0,0,0,0,0,0}; - uint8_t rawData[6] = {0, 0, 0, 0, 0, 0}; - uint8_t selfTest[6]; - int16_t gAvg[3], aAvg[3], aSTAvg[3], gSTAvg[3]; - float factoryTrim[6]; - uint8_t FS = 0; - - writeByte(MPU9250_ADDRESS, SMPLRT_DIV, 0x00); // Set gyro sample rate to 1 kHz - writeByte(MPU9250_ADDRESS, CONFIG, 0x02); // Set gyro sample rate to 1 kHz and DLPF to 92 Hz - writeByte(MPU9250_ADDRESS, GYRO_CONFIG, 1<<FS); // Set full scale range for the gyro to 250 dps - writeByte(MPU9250_ADDRESS, ACCEL_CONFIG2, 0x02); // Set accelerometer rate to 1 kHz and bandwidth to 92 Hz - writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, 1<<FS); // Set full scale range for the accelerometer to 2 g - - for( int ii = 0; ii < 200; ii++) { // get average current values of gyro and acclerometer - - readBytes(MPU9250_ADDRESS, ACCEL_XOUT_H, 6, &rawData[0]); // Read the six raw data registers into data array - aAvg[0] += (int16_t)(((int16_t)rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value - aAvg[1] += (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ; - aAvg[2] += (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ; - - readBytes(MPU9250_ADDRESS, GYRO_XOUT_H, 6, &rawData[0]); // Read the six raw data registers sequentially into data array - gAvg[0] += (int16_t)(((int16_t)rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value - gAvg[1] += (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ; - gAvg[2] += (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ; - } - - for (int ii =0; ii < 3; ii++) { // Get average of 200 values and store as average current readings - aAvg[ii] /= 200; - gAvg[ii] /= 200; - } - -// Configure the accelerometer for self-test - writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, 0xE0); // Enable self test on all three axes and set accelerometer range to +/- 2 g - writeByte(MPU9250_ADDRESS, GYRO_CONFIG, 0xE0); // Enable self test on all three axes and set gyro range to +/- 250 degrees/s - //delay(25); // Delay a while to let the device stabilize - - for( int ii = 0; ii < 200; ii++) { // get average self-test values of gyro and acclerometer - - readBytes(MPU9250_ADDRESS, ACCEL_XOUT_H, 6, &rawData[0]); // Read the six raw data registers into data array - aSTAvg[0] += (int16_t)(((int16_t)rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value - aSTAvg[1] += (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ; - aSTAvg[2] += (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ; - - readBytes(MPU9250_ADDRESS, GYRO_XOUT_H, 6, &rawData[0]); // Read the six raw data registers sequentially into data array - gSTAvg[0] += (int16_t)(((int16_t)rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value - gSTAvg[1] += (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ; - gSTAvg[2] += (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ; - } - - for (int ii =0; ii < 3; ii++) { // Get average of 200 values and store as average self-test readings - aSTAvg[ii] /= 200; - gSTAvg[ii] /= 200; - } - -// Configure the gyro and accelerometer for normal operation - writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, 0x00); - writeByte(MPU9250_ADDRESS, GYRO_CONFIG, 0x00); - //delay(25); // Delay a while to let the device stabilize - - // Retrieve accelerometer and gyro factory Self-Test Code from USR_Reg - selfTest[0] = readByte(MPU9250_ADDRESS, SELF_TEST_X_ACCEL); // X-axis accel self-test results - selfTest[1] = readByte(MPU9250_ADDRESS, SELF_TEST_Y_ACCEL); // Y-axis accel self-test results - selfTest[2] = readByte(MPU9250_ADDRESS, SELF_TEST_Z_ACCEL); // Z-axis accel self-test results - selfTest[3] = readByte(MPU9250_ADDRESS, SELF_TEST_X_GYRO); // X-axis gyro self-test results - selfTest[4] = readByte(MPU9250_ADDRESS, SELF_TEST_Y_GYRO); // Y-axis gyro self-test results - selfTest[5] = readByte(MPU9250_ADDRESS, SELF_TEST_Z_GYRO); // Z-axis gyro self-test results - - // Retrieve factory self-test value from self-test code reads - factoryTrim[0] = (float)(2620/1<<FS)*(pow( (float)1.01 , ((float)selfTest[0] - (float)1.0) )); // FT[Xa] factory trim calculation - factoryTrim[1] = (float)(2620/1<<FS)*(pow( (float)1.01 , ((float)selfTest[1] - (float)1.0) )); // FT[Ya] factory trim calculation - factoryTrim[2] = (float)(2620/1<<FS)*(pow( (float)1.01 , ((float)selfTest[2] - (float)1.0) )); // FT[Za] factory trim calculation - factoryTrim[3] = (float)(2620/1<<FS)*(pow( (float)1.01 , ((float)selfTest[3] - (float)1.0) )); // FT[Xg] factory trim calculation - factoryTrim[4] = (float)(2620/1<<FS)*(pow( (float)1.01 , ((float)selfTest[4] - (float)1.0) )); // FT[Yg] factory trim calculation - factoryTrim[5] = (float)(2620/1<<FS)*(pow( (float)1.01 , ((float)selfTest[5] - (float)1.0) )); // FT[Zg] factory trim calculation - -// Report results as a ratio of (STR - FT)/FT; the change from Factory Trim of the Self-Test Response -// To get percent, must multiply by 100 - for (int i = 0; i < 3; i++) { - SelfTest[i] = (float)100.0*((float)(aSTAvg[i] - aAvg[i]))/factoryTrim[i]; // Report percent differences - SelfTest[i+3] = (float)100.0*((float)(gSTAvg[i] - gAvg[i]))/factoryTrim[i+3]; // Report percent differences - } - -} \ No newline at end of file