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Revision 1:b36bbc1c6d27, committed 2020-04-11
- Comitter:
- demayer
- Date:
- Sat Apr 11 08:15:48 2020 +0000
- Parent:
- 0:6bf0743ece18
- Commit message:
- IMU-library in .h und .cpp file aufgeteilt
Changed in this revision
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/MPU9250.cpp Sat Apr 11 08:15:48 2020 +0000
@@ -0,0 +1,877 @@
+#include "MPU9250.h"
+
+
+
+uint8_t Ascale = AFS_2G; // AFS_2G, AFS_4G, AFS_8G, AFS_16G
+uint8_t Gscale = GFS_250DPS; // GFS_250DPS, GFS_500DPS, GFS_1000DPS, GFS_2000DPS
+uint8_t Mscale = MFS_16BITS; // MFS_14BITS or MFS_16BITS, 14-bit or 16-bit magnetometer resolution
+uint8_t Mmode = 0x06; // Either 8 Hz 0x02) or 100 Hz (0x06) magnetometer data ODR
+float aRes, gRes, mRes; // scale resolutions per LSB for the sensors
+
+//Set up I2C, (SDA,SCL)
+I2C i2c(PB_9, PB_8);
+
+DigitalOut myled(LED1);
+
+// Pin definitions
+int intPin = 12; // These can be changed, 2 and 3 are the Arduinos ext int pins
+
+int16_t accelCount[3]; // Stores the 16-bit signed accelerometer sensor output
+int16_t gyroCount[3]; // Stores the 16-bit signed gyro sensor output
+int16_t magCount[3]; // Stores the 16-bit signed magnetometer sensor output
+float magCalibration[3] = {0, 0, 0}, magbias[3] = {0, 0, 0}; // Factory mag calibration and mag bias
+float gyroBias[3] = {0, 0, 0}, accelBias[3] = {0, 0, 0}; // Bias corrections for gyro and accelerometer
+float ax, ay, az, gx, gy, gz, mx, my, mz; // variables to hold latest sensor data values
+int16_t tempCount; // Stores the real internal chip temperature in degrees Celsius
+float temperature;
+float SelfTest[6];
+
+int delt_t = 0; // used to control display output rate
+int _count = 0; // used to control display output rate
+
+// parameters for 6 DoF sensor fusion calculations
+float PI = 3.14159265358979323846f;
+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
+float beta = sqrt(3.0f / 4.0f) * GyroMeasError; // compute beta
+float GyroMeasDrift = PI * (1.0f / 180.0f); // gyroscope measurement drift in rad/s/s (start at 0.0 deg/s/s)
+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
+#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
+#define Ki 0.0f
+
+float pitch, yaw, roll;
+float vx, vy, vz;
+float deltat = 0.0f; // integration interval for both filter schemes
+int lastUpdate = 0, firstUpdate = 0, Now = 0; // used to calculate integration interval // used to calculate integration interval
+float q[4] = {1.0f, 0.0f, 0.0f, 0.0f}; // vector to hold quaternion
+float v_trans[3] = {0.0f, 0.0f, 0.0f}; // vector to hold translative velocities
+float a_old[3] = {0.00f, 0.00f, 0.00f};
+float eInt[3] = {0.0f, 0.0f, 0.0f}; // vector to hold integral error for Mahony method
+
+
+accData_t myData;
+MPU9250 mpu9250;
+Timer t;
+Serial pc(USBTX, USBRX); // tx, rx
+
+#define SAMPLE_TIME 100
+
+
+float sum = 0;
+uint32_t sumCount = 0;
+char buffer[14];
+
+
+//===================================================================================================================
+//====== Set of useful function to access acceleratio, gyroscope, and temperature data
+//===================================================================================================================
+
+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::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::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::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::readAccelData(int16_t * destination)
+{
+ 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]) ;
+}
+
+void MPU9250::readGyroData(int16_t * destination)
+{
+ 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]) ;
+}
+
+void MPU9250::readMagData(int16_t * destination)
+{
+ 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]) ;
+ }
+ }
+}
+
+int16_t MPU9250::readTempData()
+{
+ 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
+ return (int16_t)(((int16_t)rawData[0]) << 8 | rawData[1]) ; // Turn the MSB and LSB into a 16-bit value
+}
+
+
+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)
+{
+ // 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);
+}
+
+
+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(float * dest1, float * dest2)
+{
+ 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]);
+ */
+ dest1[0] = (float) gyro_bias[0]/(float) gyrosensitivity; // construct gyro bias in deg/s for later manual subtraction
+ dest1[1] = (float) gyro_bias[1]/(float) gyrosensitivity;
+ dest1[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
+ dest2[0] = (float)accel_bias[0]/(float)accelsensitivity;
+ dest2[1] = (float)accel_bias[1]/(float)accelsensitivity;
+ dest2[2] = (float)accel_bias[2]/(float)accelsensitivity;
+}
+
+
+// Accelerometer and gyroscope self test; check calibration wrt factory settings
+void MPU9250::MPU9250SelfTest(float * destination) // Should return percent deviation from factory trim values, +/- 14 or less deviation is a pass
+{
+ 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
+ wait(0.025); // 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);
+ wait(0.025); // 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( 1.01, ((float)selfTest[0] - 1.0) )); // FT[Xa] factory trim calculation
+ factoryTrim[1] = (float)(2620/1<<FS)*(pow( 1.01, ((float)selfTest[1] - 1.0) )); // FT[Ya] factory trim calculation
+ factoryTrim[2] = (float)(2620/1<<FS)*(pow( 1.01, ((float)selfTest[2] - 1.0) )); // FT[Za] factory trim calculation
+ factoryTrim[3] = (float)(2620/1<<FS)*(pow( 1.01, ((float)selfTest[3] - 1.0) )); // FT[Xg] factory trim calculation
+ factoryTrim[4] = (float)(2620/1<<FS)*(pow( 1.01, ((float)selfTest[4] - 1.0) )); // FT[Yg] factory trim calculation
+ factoryTrim[5] = (float)(2620/1<<FS)*(pow( 1.01, ((float)selfTest[5] - 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++) {
+ destination[i] = 100.0*((float)(aSTAvg[i] - aAvg[i]))/factoryTrim[i]; // Report percent differences
+ destination[i+3] = 100.0*((float)(gSTAvg[i] - gAvg[i]))/factoryTrim[i+3]; // Report percent differences
+ }
+
+}
+
+
+
+// Implementation of Sebastian Madgwick's "...efficient orientation filter for... inertial/magnetic sensor arrays"
+// (see http://www.x-io.co.uk/category/open-source/ for examples and more details)
+// which fuses acceleration, rotation rate, and magnetic moments to produce a quaternion-based estimate of absolute
+// device orientation -- which can be converted to yaw, pitch, and roll. Useful for stabilizing quadcopters, etc.
+// The performance of the orientation filter is at least as good as conventional Kalman-based filtering algorithms
+// but is much less computationally intensive---it can be performed on a 3.3 V Pro Mini operating at 8 MHz!
+void MPU9250::MadgwickQuaternionUpdate(float ax, float ay, float az, float gx, float gy, float gz, float mx, float my, float mz)
+{
+ float q1 = q[0], q2 = q[1], q3 = q[2], q4 = q[3]; // short name local variable for readability
+ float norm;
+ float hx, hy, _2bx, _2bz;
+ float s1, s2, s3, s4;
+ float qDot1, qDot2, qDot3, qDot4;
+
+ // Auxiliary variables to avoid repeated arithmetic
+ float _2q1mx;
+ float _2q1my;
+ float _2q1mz;
+ float _2q2mx;
+ float _4bx;
+ float _4bz;
+ float _2q1 = 2.0f * q1;
+ float _2q2 = 2.0f * q2;
+ float _2q3 = 2.0f * q3;
+ float _2q4 = 2.0f * q4;
+ float _2q1q3 = 2.0f * q1 * q3;
+ float _2q3q4 = 2.0f * q3 * q4;
+ float q1q1 = q1 * q1;
+ float q1q2 = q1 * q2;
+ float q1q3 = q1 * q3;
+ float q1q4 = q1 * q4;
+ float q2q2 = q2 * q2;
+ float q2q3 = q2 * q3;
+ float q2q4 = q2 * q4;
+ float q3q3 = q3 * q3;
+ float q3q4 = q3 * q4;
+ float q4q4 = q4 * q4;
+
+ // Normalise accelerometer measurement
+ norm = sqrt(ax * ax + ay * ay + az * az);
+ if (norm == 0.0f) return; // handle NaN
+ norm = 1.0f/norm;
+ ax *= norm;
+ ay *= norm;
+ az *= norm;
+
+ // Normalise magnetometer measurement
+ norm = sqrt(mx * mx + my * my + mz * mz);
+ if (norm == 0.0f) return; // handle NaN
+ norm = 1.0f/norm;
+ mx *= norm;
+ my *= norm;
+ mz *= norm;
+
+ // Reference direction of Earth's magnetic field
+ _2q1mx = 2.0f * q1 * mx;
+ _2q1my = 2.0f * q1 * my;
+ _2q1mz = 2.0f * q1 * mz;
+ _2q2mx = 2.0f * q2 * mx;
+ hx = mx * q1q1 - _2q1my * q4 + _2q1mz * q3 + mx * q2q2 + _2q2 * my * q3 + _2q2 * mz * q4 - mx * q3q3 - mx * q4q4;
+ hy = _2q1mx * q4 + my * q1q1 - _2q1mz * q2 + _2q2mx * q3 - my * q2q2 + my * q3q3 + _2q3 * mz * q4 - my * q4q4;
+ _2bx = sqrt(hx * hx + hy * hy);
+ _2bz = -_2q1mx * q3 + _2q1my * q2 + mz * q1q1 + _2q2mx * q4 - mz * q2q2 + _2q3 * my * q4 - mz * q3q3 + mz * q4q4;
+ _4bx = 2.0f * _2bx;
+ _4bz = 2.0f * _2bz;
+
+ // Gradient decent algorithm corrective step
+ 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);
+ 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);
+ 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);
+ 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);
+ norm = sqrt(s1 * s1 + s2 * s2 + s3 * s3 + s4 * s4); // normalise step magnitude
+ norm = 1.0f/norm;
+ s1 *= norm;
+ s2 *= norm;
+ s3 *= norm;
+ s4 *= norm;
+
+ // Compute rate of change of quaternion
+ qDot1 = 0.5f * (-q2 * gx - q3 * gy - q4 * gz) - beta * s1;
+ qDot2 = 0.5f * (q1 * gx + q3 * gz - q4 * gy) - beta * s2;
+ qDot3 = 0.5f * (q1 * gy - q2 * gz + q4 * gx) - beta * s3;
+ qDot4 = 0.5f * (q1 * gz + q2 * gy - q3 * gx) - beta * s4;
+
+ // Integrate to yield quaternion
+ q1 += qDot1 * deltat;
+ q2 += qDot2 * deltat;
+ q3 += qDot3 * deltat;
+ q4 += qDot4 * deltat;
+ norm = sqrt(q1 * q1 + q2 * q2 + q3 * q3 + q4 * q4); // normalise quaternion
+ norm = 1.0f/norm;
+ q[0] = q1 * norm;
+ q[1] = q2 * norm;
+ q[2] = q3 * norm;
+ q[3] = q4 * norm;
+
+}
+
+
+
+// Similar to Madgwick scheme but uses proportional and integral filtering on the error between estimated reference vectors and
+// measured ones.
+void MPU9250::MahonyQuaternionUpdate(float ax, float ay, float az, float gx, float gy, float gz, float mx, float my, float mz)
+{
+ float q1 = q[0], q2 = q[1], q3 = q[2], q4 = q[3]; // short name local variable for readability
+ float norm;
+ float hx, hy, bx, bz;
+ float vx, vy, vz, wx, wy, wz;
+ float ex, ey, ez;
+ float pa, pb, pc;
+
+ // Auxiliary variables to avoid repeated arithmetic
+ float q1q1 = q1 * q1;
+ float q1q2 = q1 * q2;
+ float q1q3 = q1 * q3;
+ float q1q4 = q1 * q4;
+ float q2q2 = q2 * q2;
+ float q2q3 = q2 * q3;
+ float q2q4 = q2 * q4;
+ float q3q3 = q3 * q3;
+ float q3q4 = q3 * q4;
+ float q4q4 = q4 * q4;
+
+ // Normalise accelerometer measurement
+ norm = sqrt(ax * ax + ay * ay + az * az);
+ if (norm == 0.0f) return; // handle NaN
+ norm = 1.0f / norm; // use reciprocal for division
+ ax *= norm;
+ ay *= norm;
+ az *= norm;
+
+ // Normalise magnetometer measurement
+ norm = sqrt(mx * mx + my * my + mz * mz);
+ if (norm == 0.0f) return; // handle NaN
+ norm = 1.0f / norm; // use reciprocal for division
+ mx *= norm;
+ my *= norm;
+ mz *= norm;
+
+ // Reference direction of Earth's magnetic field
+ hx = 2.0f * mx * (0.5f - q3q3 - q4q4) + 2.0f * my * (q2q3 - q1q4) + 2.0f * mz * (q2q4 + q1q3);
+ hy = 2.0f * mx * (q2q3 + q1q4) + 2.0f * my * (0.5f - q2q2 - q4q4) + 2.0f * mz * (q3q4 - q1q2);
+ bx = sqrt((hx * hx) + (hy * hy));
+ bz = 2.0f * mx * (q2q4 - q1q3) + 2.0f * my * (q3q4 + q1q2) + 2.0f * mz * (0.5f - q2q2 - q3q3);
+
+ // Estimated direction of gravity and magnetic field
+ vx = 2.0f * (q2q4 - q1q3);
+ vy = 2.0f * (q1q2 + q3q4);
+ vz = q1q1 - q2q2 - q3q3 + q4q4;
+ wx = 2.0f * bx * (0.5f - q3q3 - q4q4) + 2.0f * bz * (q2q4 - q1q3);
+ wy = 2.0f * bx * (q2q3 - q1q4) + 2.0f * bz * (q1q2 + q3q4);
+ wz = 2.0f * bx * (q1q3 + q2q4) + 2.0f * bz * (0.5f - q2q2 - q3q3);
+
+ // Error is cross product between estimated direction and measured direction of gravity
+ ex = (ay * vz - az * vy) + (my * wz - mz * wy);
+ ey = (az * vx - ax * vz) + (mz * wx - mx * wz);
+ ez = (ax * vy - ay * vx) + (mx * wy - my * wx);
+ if (Ki > 0.0f) {
+ eInt[0] += ex; // accumulate integral error
+ eInt[1] += ey;
+ eInt[2] += ez;
+ } else {
+ eInt[0] = 0.0f; // prevent integral wind up
+ eInt[1] = 0.0f;
+ eInt[2] = 0.0f;
+ }
+
+ // Apply feedback terms
+ gx = gx + Kp * ex + Ki * eInt[0];
+ gy = gy + Kp * ey + Ki * eInt[1];
+ gz = gz + Kp * ez + Ki * eInt[2];
+
+ // Integrate rate of change of quaternion
+ pa = q2;
+ pb = q3;
+ pc = q4;
+ q1 = q1 + (-q2 * gx - q3 * gy - q4 * gz) * (0.5f * deltat);
+ q2 = pa + (q1 * gx + pb * gz - pc * gy) * (0.5f * deltat);
+ q3 = pb + (q1 * gy - pa * gz + pc * gx) * (0.5f * deltat);
+ q4 = pc + (q1 * gz + pa * gy - pb * gx) * (0.5f * deltat);
+
+ // Normalise quaternion
+ norm = sqrt(q1 * q1 + q2 * q2 + q3 * q3 + q4 * q4);
+ norm = 1.0f / norm;
+ q[0] = q1 * norm;
+ q[1] = q2 * norm;
+ q[2] = q3 * norm;
+ q[3] = q4 * norm;
+
+}
+
+// Integrates the acceleration to get the boards translative velocity
+void MPU9250::velocityUpdate(float ax, float ay, float az)
+{
+ // short name local variable for readability
+
+ v_trans[0] = deltat*0.5*(a_old[0] + ax*GRAVITATION) + v_trans[0];
+ v_trans[1] = deltat*0.5*(a_old[1] + ay*GRAVITATION) + v_trans[1];
+ v_trans[2] = deltat*0.5*(a_old[2] + az*GRAVITATION + GRAVITATION) + v_trans[2];
+
+ a_old[0] = ax*GRAVITATION;
+ a_old[1] = ay*GRAVITATION;
+ a_old[2] = az*GRAVITATION;
+}
+
+void MPU9250::readIMU()
+{
+ // If intPin goes high, all data registers have new data
+ if(mpu9250.readByte(MPU9250_ADDRESS, INT_STATUS) & 0x01) { // On interrupt, check if data ready interrupt
+
+ mpu9250.readAccelData(accelCount); // Read the x/y/z adc values
+ // 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];
+
+ mpu9250.readGyroData(gyroCount); // Read the x/y/z adc values
+ // 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];
+
+ mpu9250.readMagData(magCount); // Read the x/y/z adc values
+ // Calculate the magnetometer values in milliGauss
+ // Include factory calibration per data sheet and user environmental corrections
+ mx = (float)magCount[0]*mRes*magCalibration[0] - magbias[0]; // get actual magnetometer value, this depends on scale being set
+ my = (float)magCount[1]*mRes*magCalibration[1] - magbias[1];
+ mz = (float)magCount[2]*mRes*magCalibration[2] - magbias[2];
+ }
+
+ pc.printf("ax, ay, az, delta_t;%f;%f;%f;%f\n\r", ax, ay, az*GRAVITATION + GRAVITATION, deltat);
+
+ Now = t.read_us();
+
+ deltat = (float)((Now - lastUpdate)/1000000.0f) ; // set integration time by time elapsed since last filter update
+ lastUpdate = Now;
+
+ sum += deltat;
+ sumCount++;
+
+
+ mpu9250.velocityUpdate(ax, ay, az);
+
+ // Pass gyro rate as rad/s
+ mpu9250.MadgwickQuaternionUpdate(ax, ay, az, gx*PI/180.0f, gy*PI/180.0f, gz*PI/180.0f, my, mx, mz);
+ //mpu9250.MahonyQuaternionUpdate(ax, ay, az, gx*PI/180.0f, gy*PI/180.0f, gz*PI/180.0f, my, mx, mz);
+
+ // Serial print and/or display at 0.5 s rate independent of data rates
+ delt_t = t.read_ms() - _count;
+
+ //-----------------------------------------
+ // Update displayed value
+ if (delt_t > SAMPLE_TIME) {
+
+
+
+ //pc.printf("vx, vy, vz: %f %f %f\n\r", v_trans[0], v_trans[1], v_trans[2]);
+
+
+ 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]);
+ pitch = -asin(2.0f * (q[1] * q[3] - q[0] * q[2]));
+ 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]);
+ pitch *= 180.0f / PI;
+ yaw *= 180.0f / PI;
+ yaw -= 2.93f; // Declination at 8572 Berg TG: +2° 56'
+ roll *= 180.0f / PI;
+
+ myData.ax = yaw;
+ myData.ay = pitch;
+ myData.az = roll;
+
+
+ myled= !myled;
+ _count = t.read_ms();
+
+ if(_count > 1<<21) {
+ t.start(); // start the timer over again if ~30 minutes has passed
+ _count = 0;
+ deltat= 0;
+ lastUpdate = t.read_us();
+ }
+ sum = 0;
+ sumCount = 0;
+ }
+}
+
+
+void MPU9250::imuSetup()
+{
+ //Set up I2C
+ i2c.frequency(400000); // use fast (400 kHz) I2C
+
+ pc.printf("CPU SystemCoreClock is %d Hz\r\n", SystemCoreClock);
+
+ t.start();
+// lcd.setBrightness(0.05);
+
+
+ // Read the WHO_AM_I register, this is a good test of communication
+ uint8_t whoami = mpu9250.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");
+ sprintf(buffer, "0x%x", whoami);
+ wait(1);
+
+ mpu9250.resetMPU9250(); // Reset registers to default in preparation for device calibration
+ mpu9250.MPU9250SelfTest(SelfTest); // 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]);
+ mpu9250.calibrateMPU9250(gyroBias, accelBias); // 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);
+ mpu9250.initMPU9250();
+ pc.printf("MPU9250 initialized for active data mode....\n\r"); // Initialize device for active mode read of acclerometer, gyroscope, and temperature
+ mpu9250.initAK8963(magCalibration);
+ pc.printf("AK8963 initialized for active data mode....\n\r"); // Initialize device for active mode read of magnetometer
+ 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);
+ sprintf(buffer, "WHO_AM_I 0x%x", whoami);
+
+ while(1) {
+ // Loop forever if communication doesn't happen
+ pc.printf("no IMU detected (verify if it's plugged in)\n\r");
+ }
+ }
+
+ mpu9250.getAres(); // Get accelerometer sensitivity
+ mpu9250.getGres(); // Get gyro sensitivity
+ mpu9250.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);
+ magbias[0] = +470.; // User environmental x-axis correction in milliGauss, should be automatically calculated
+ magbias[1] = +120.; // User environmental x-axis correction in milliGauss
+ magbias[2] = +125.; // User environmental x-axis correction in milliGauss
+}
+
+accData_t MPU9250::getVelocityFromIMU(){
+ readIMU();
+
+ return myData;
+}
\ No newline at end of file
--- a/MPU9250.h Sat Mar 28 15:28:19 2020 +0000
+++ b/MPU9250.h Sat Apr 11 08:15:48 2020 +0000
@@ -1,10 +1,10 @@
#ifndef MPU9250_H
#define MPU9250_H
-
+
#include "mbed.h"
#include "math.h"
-
-// See also MPU-9250 Register Map and Descriptions, Revision 4.0, RM-MPU-9250A-00, Rev. 1.4, 9/9/2013 for registers not listed in
+
+// See also MPU-9250 Register Map and Descriptions, Revision 4.0, RM-MPU-9250A-00, Rev. 1.4, 9/9/2013 for registers not listed in
// above document; the MPU9250 and MPU9150 are virtually identical but the latter has a different register map
//
//Magnetometer Registers
@@ -26,22 +26,13 @@
#define AK8963_ASAY 0x11 // Fuse ROM y-axis sensitivity adjustment value
#define AK8963_ASAZ 0x12 // Fuse ROM z-axis sensitivity adjustment value
-#define SELF_TEST_X_GYRO 0x00
-#define SELF_TEST_Y_GYRO 0x01
+#define SELF_TEST_X_GYRO 0x00
+#define SELF_TEST_Y_GYRO 0x01
#define SELF_TEST_Z_GYRO 0x02
-
-/*#define X_FINE_GAIN 0x03 // [7:0] fine gain
-#define Y_FINE_GAIN 0x04
-#define Z_FINE_GAIN 0x05
-#define XA_OFFSET_H 0x06 // User-defined trim values for accelerometer
-#define XA_OFFSET_L_TC 0x07
-#define YA_OFFSET_H 0x08
-#define YA_OFFSET_L_TC 0x09
-#define ZA_OFFSET_H 0x0A
-#define ZA_OFFSET_L_TC 0x0B */
+#define GRAVITATION 9.80665
#define SELF_TEST_X_ACCEL 0x0D
-#define SELF_TEST_Y_ACCEL 0x0E
+#define SELF_TEST_Y_ACCEL 0x0E
#define SELF_TEST_Z_ACCEL 0x0F
#define SELF_TEST_A 0x10
@@ -57,15 +48,15 @@
#define GYRO_CONFIG 0x1B
#define ACCEL_CONFIG 0x1C
#define ACCEL_CONFIG2 0x1D
-#define LP_ACCEL_ODR 0x1E
-#define WOM_THR 0x1F
+#define LP_ACCEL_ODR 0x1E
+#define WOM_THR 0x1F
#define MOT_DUR 0x20 // Duration counter threshold for motion interrupt generation, 1 kHz rate, LSB = 1 ms
#define ZMOT_THR 0x21 // Zero-motion detection threshold bits [7:0]
#define ZRMOT_DUR 0x22 // Duration counter threshold for zero motion interrupt generation, 16 Hz rate, LSB = 64 ms
#define FIFO_EN 0x23
-#define I2C_MST_CTRL 0x24
+#define I2C_MST_CTRL 0x24
#define I2C_SLV0_ADDR 0x25
#define I2C_SLV0_REG 0x26
#define I2C_SLV0_CTRL 0x27
@@ -141,7 +132,7 @@
#define DMP_RW_PNT 0x6E // Set read/write pointer to a specific start address in specified DMP bank
#define DMP_REG 0x6F // Register in DMP from which to read or to which to write
#define DMP_REG_1 0x70
-#define DMP_REG_2 0x71
+#define DMP_REG_2 0x71
#define FIFO_COUNTH 0x72
#define FIFO_COUNTL 0x73
#define FIFO_R_W 0x74
@@ -153,7 +144,7 @@
#define ZA_OFFSET_H 0x7D
#define ZA_OFFSET_L 0x7E
-// Using the MSENSR-9250 breakout board, ADO is set to 0
+// Using the MSENSR-9250 breakout board, ADO is set to 0
// Seven-bit device address is 110100 for ADO = 0 and 110101 for ADO = 1
//mbed uses the eight-bit device address, so shift seven-bit addresses left by one!
#define ADO 0
@@ -161,714 +152,84 @@
#define MPU9250_ADDRESS 0x69<<1 // Device address when ADO = 1
#else
#define MPU9250_ADDRESS 0x68<<1 // Device address when ADO = 0
-#endif
+#endif
+
// Set initial input parameters
enum Ascale {
- AFS_2G = 0,
- AFS_4G,
- AFS_8G,
- AFS_16G
+ AFS_2G = 0,
+ AFS_4G,
+ AFS_8G,
+ AFS_16G
};
enum Gscale {
- GFS_250DPS = 0,
- GFS_500DPS,
- GFS_1000DPS,
- GFS_2000DPS
+ GFS_250DPS = 0,
+ GFS_500DPS,
+ GFS_1000DPS,
+ GFS_2000DPS
};
enum Mscale {
- MFS_14BITS = 0, // 0.6 mG per LSB
- MFS_16BITS // 0.15 mG per LSB
+ MFS_14BITS = 0, // 0.6 mG per LSB
+ MFS_16BITS // 0.15 mG per LSB
};
-uint8_t Ascale = AFS_2G; // AFS_2G, AFS_4G, AFS_8G, AFS_16G
-uint8_t Gscale = GFS_250DPS; // GFS_250DPS, GFS_500DPS, GFS_1000DPS, GFS_2000DPS
-uint8_t Mscale = MFS_16BITS; // MFS_14BITS or MFS_16BITS, 14-bit or 16-bit magnetometer resolution
-uint8_t Mmode = 0x06; // Either 8 Hz 0x02) or 100 Hz (0x06) magnetometer data ODR
-float aRes, gRes, mRes; // scale resolutions per LSB for the sensors
-
-//Set up I2C, (SDA,SCL)
-I2C i2c(PB_9, PB_8);
-
-DigitalOut myled(LED1);
-
-// Pin definitions
-int intPin = 12; // These can be changed, 2 and 3 are the Arduinos ext int pins
-
-int16_t accelCount[3]; // Stores the 16-bit signed accelerometer sensor output
-int16_t gyroCount[3]; // Stores the 16-bit signed gyro sensor output
-int16_t magCount[3]; // Stores the 16-bit signed magnetometer sensor output
-float magCalibration[3] = {0, 0, 0}, magbias[3] = {0, 0, 0}; // Factory mag calibration and mag bias
-float gyroBias[3] = {0, 0, 0}, accelBias[3] = {0, 0, 0}; // Bias corrections for gyro and accelerometer
-float ax, ay, az, gx, gy, gz, mx, my, mz; // variables to hold latest sensor data values
-int16_t tempCount; // Stores the real internal chip temperature in degrees Celsius
-float temperature;
-float SelfTest[6];
-
-int delt_t = 0; // used to control display output rate
-int _count = 0; // used to control display output rate
-
-// parameters for 6 DoF sensor fusion calculations
-float PI = 3.14159265358979323846f;
-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
-float beta = sqrt(3.0f / 4.0f) * GyroMeasError; // compute beta
-float GyroMeasDrift = PI * (1.0f / 180.0f); // gyroscope measurement drift in rad/s/s (start at 0.0 deg/s/s)
-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
-#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
-#define Ki 0.0f
-
-float pitch, yaw, roll;
-float deltat = 0.0f; // integration interval for both filter schemes
-int lastUpdate = 0, firstUpdate = 0, Now = 0; // used to calculate integration interval // used to calculate integration interval
-float q[4] = {1.0f, 0.0f, 0.0f, 0.0f}; // vector to hold quaternion
-float eInt[3] = {0.0f, 0.0f, 0.0f}; // vector to hold integral error for Mahony method
-
-class MPU9250 {
-
- protected:
-
- public:
- //===================================================================================================================
-//====== Set of useful function to access acceleratio, gyroscope, and temperature data
-//===================================================================================================================
-
- void 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 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 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 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;
- }
-}
+typedef struct {
+ float ax;
+ float ay;
+ float az;
+}accData_t;
-void 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 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 readAccelData(int16_t * destination)
-{
- 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]) ;
-}
-
-void readGyroData(int16_t * destination)
-{
- 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]) ;
-}
-
-void readMagData(int16_t * destination)
-{
- 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]) ;
- }
- }
-}
-
-int16_t readTempData()
-{
- 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
- return (int16_t)(((int16_t)rawData[0]) << 8 | rawData[1]) ; // Turn the MSB and LSB into a 16-bit value
-}
-
-
-void 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 initAK8963(float * destination)
-{
- // 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);
-}
+class MPU9250 {
-void 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
+public:
+ //------------------------------------------------------------------------------
+ // Function prototypes
- // 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
+ void writeByte(uint8_t address, uint8_t subAddress, uint8_t data);
- // 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
-}
+ char readByte(uint8_t address, uint8_t subAddress);
-// 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 calibrateMPU9250(float * dest1, float * dest2)
-{
- 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
+ void readBytes(uint8_t address, uint8_t subAddress, uint8_t count, uint8_t * dest);
-// 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
+ void getMres();
- 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;
+ void getGres();
-/// 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]);
-*/
- dest1[0] = (float) gyro_bias[0]/(float) gyrosensitivity; // construct gyro bias in deg/s for later manual subtraction
- dest1[1] = (float) gyro_bias[1]/(float) gyrosensitivity;
- dest1[2] = (float) gyro_bias[2]/(float) gyrosensitivity;
+ void getAres();
-// 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
- }
+ void readAccelData(int16_t * destination);
- // 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
- dest2[0] = (float)accel_bias[0]/(float)accelsensitivity;
- dest2[1] = (float)accel_bias[1]/(float)accelsensitivity;
- dest2[2] = (float)accel_bias[2]/(float)accelsensitivity;
-}
-
+ void readGyroData(int16_t * destination);
-// Accelerometer and gyroscope self test; check calibration wrt factory settings
-void MPU9250SelfTest(float * destination) // Should return percent deviation from factory trim values, +/- 14 or less deviation is a pass
-{
- 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
+ void readMagData(int16_t * destination);
- 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
- wait(0.025); // Delay a while to let the device stabilize
+ int16_t readTempData();
- 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);
- wait(0.025); // 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
+ void resetMPU9250();
- // Retrieve factory self-test value from self-test code reads
- factoryTrim[0] = (float)(2620/1<<FS)*(pow( 1.01 , ((float)selfTest[0] - 1.0) )); // FT[Xa] factory trim calculation
- factoryTrim[1] = (float)(2620/1<<FS)*(pow( 1.01 , ((float)selfTest[1] - 1.0) )); // FT[Ya] factory trim calculation
- factoryTrim[2] = (float)(2620/1<<FS)*(pow( 1.01 , ((float)selfTest[2] - 1.0) )); // FT[Za] factory trim calculation
- factoryTrim[3] = (float)(2620/1<<FS)*(pow( 1.01 , ((float)selfTest[3] - 1.0) )); // FT[Xg] factory trim calculation
- factoryTrim[4] = (float)(2620/1<<FS)*(pow( 1.01 , ((float)selfTest[4] - 1.0) )); // FT[Yg] factory trim calculation
- factoryTrim[5] = (float)(2620/1<<FS)*(pow( 1.01 , ((float)selfTest[5] - 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++) {
- destination[i] = 100.0*((float)(aSTAvg[i] - aAvg[i]))/factoryTrim[i]; // Report percent differences
- destination[i+3] = 100.0*((float)(gSTAvg[i] - gAvg[i]))/factoryTrim[i+3]; // Report percent differences
- }
-
-}
+ void initAK8963(float * destination);
-
+ void initMPU9250();
-// Implementation of Sebastian Madgwick's "...efficient orientation filter for... inertial/magnetic sensor arrays"
-// (see http://www.x-io.co.uk/category/open-source/ for examples and more details)
-// which fuses acceleration, rotation rate, and magnetic moments to produce a quaternion-based estimate of absolute
-// device orientation -- which can be converted to yaw, pitch, and roll. Useful for stabilizing quadcopters, etc.
-// The performance of the orientation filter is at least as good as conventional Kalman-based filtering algorithms
-// but is much less computationally intensive---it can be performed on a 3.3 V Pro Mini operating at 8 MHz!
- void MadgwickQuaternionUpdate(float ax, float ay, float az, float gx, float gy, float gz, float mx, float my, float mz)
- {
- float q1 = q[0], q2 = q[1], q3 = q[2], q4 = q[3]; // short name local variable for readability
- float norm;
- float hx, hy, _2bx, _2bz;
- float s1, s2, s3, s4;
- float qDot1, qDot2, qDot3, qDot4;
+ void calibrateMPU9250(float * dest1, float * dest2);
- // Auxiliary variables to avoid repeated arithmetic
- float _2q1mx;
- float _2q1my;
- float _2q1mz;
- float _2q2mx;
- float _4bx;
- float _4bz;
- float _2q1 = 2.0f * q1;
- float _2q2 = 2.0f * q2;
- float _2q3 = 2.0f * q3;
- float _2q4 = 2.0f * q4;
- float _2q1q3 = 2.0f * q1 * q3;
- float _2q3q4 = 2.0f * q3 * q4;
- float q1q1 = q1 * q1;
- float q1q2 = q1 * q2;
- float q1q3 = q1 * q3;
- float q1q4 = q1 * q4;
- float q2q2 = q2 * q2;
- float q2q3 = q2 * q3;
- float q2q4 = q2 * q4;
- float q3q3 = q3 * q3;
- float q3q4 = q3 * q4;
- float q4q4 = q4 * q4;
+ void MPU9250SelfTest(float * destination);
- // Normalise accelerometer measurement
- norm = sqrt(ax * ax + ay * ay + az * az);
- if (norm == 0.0f) return; // handle NaN
- norm = 1.0f/norm;
- ax *= norm;
- ay *= norm;
- az *= norm;
-
- // Normalise magnetometer measurement
- norm = sqrt(mx * mx + my * my + mz * mz);
- if (norm == 0.0f) return; // handle NaN
- norm = 1.0f/norm;
- mx *= norm;
- my *= norm;
- mz *= norm;
-
- // Reference direction of Earth's magnetic field
- _2q1mx = 2.0f * q1 * mx;
- _2q1my = 2.0f * q1 * my;
- _2q1mz = 2.0f * q1 * mz;
- _2q2mx = 2.0f * q2 * mx;
- hx = mx * q1q1 - _2q1my * q4 + _2q1mz * q3 + mx * q2q2 + _2q2 * my * q3 + _2q2 * mz * q4 - mx * q3q3 - mx * q4q4;
- hy = _2q1mx * q4 + my * q1q1 - _2q1mz * q2 + _2q2mx * q3 - my * q2q2 + my * q3q3 + _2q3 * mz * q4 - my * q4q4;
- _2bx = sqrt(hx * hx + hy * hy);
- _2bz = -_2q1mx * q3 + _2q1my * q2 + mz * q1q1 + _2q2mx * q4 - mz * q2q2 + _2q3 * my * q4 - mz * q3q3 + mz * q4q4;
- _4bx = 2.0f * _2bx;
- _4bz = 2.0f * _2bz;
+ void MadgwickQuaternionUpdate(float ax, float ay, float az, float gx, float gy, float gz, float mx, float my, float mz);
- // Gradient decent algorithm corrective step
- 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);
- 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);
- 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);
- 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);
- norm = sqrt(s1 * s1 + s2 * s2 + s3 * s3 + s4 * s4); // normalise step magnitude
- norm = 1.0f/norm;
- s1 *= norm;
- s2 *= norm;
- s3 *= norm;
- s4 *= norm;
-
- // Compute rate of change of quaternion
- qDot1 = 0.5f * (-q2 * gx - q3 * gy - q4 * gz) - beta * s1;
- qDot2 = 0.5f * (q1 * gx + q3 * gz - q4 * gy) - beta * s2;
- qDot3 = 0.5f * (q1 * gy - q2 * gz + q4 * gx) - beta * s3;
- qDot4 = 0.5f * (q1 * gz + q2 * gy - q3 * gx) - beta * s4;
-
- // Integrate to yield quaternion
- q1 += qDot1 * deltat;
- q2 += qDot2 * deltat;
- q3 += qDot3 * deltat;
- q4 += qDot4 * deltat;
- norm = sqrt(q1 * q1 + q2 * q2 + q3 * q3 + q4 * q4); // normalise quaternion
- norm = 1.0f/norm;
- q[0] = q1 * norm;
- q[1] = q2 * norm;
- q[2] = q3 * norm;
- q[3] = q4 * norm;
-
- }
-
-
-
- // Similar to Madgwick scheme but uses proportional and integral filtering on the error between estimated reference vectors and
- // measured ones.
- void MahonyQuaternionUpdate(float ax, float ay, float az, float gx, float gy, float gz, float mx, float my, float mz)
- {
- float q1 = q[0], q2 = q[1], q3 = q[2], q4 = q[3]; // short name local variable for readability
- float norm;
- float hx, hy, bx, bz;
- float vx, vy, vz, wx, wy, wz;
- float ex, ey, ez;
- float pa, pb, pc;
-
- // Auxiliary variables to avoid repeated arithmetic
- float q1q1 = q1 * q1;
- float q1q2 = q1 * q2;
- float q1q3 = q1 * q3;
- float q1q4 = q1 * q4;
- float q2q2 = q2 * q2;
- float q2q3 = q2 * q3;
- float q2q4 = q2 * q4;
- float q3q3 = q3 * q3;
- float q3q4 = q3 * q4;
- float q4q4 = q4 * q4;
-
- // Normalise accelerometer measurement
- norm = sqrt(ax * ax + ay * ay + az * az);
- if (norm == 0.0f) return; // handle NaN
- norm = 1.0f / norm; // use reciprocal for division
- ax *= norm;
- ay *= norm;
- az *= norm;
+ void MahonyQuaternionUpdate(float ax, float ay, float az, float gx, float gy, float gz, float mx, float my, float mz);
- // Normalise magnetometer measurement
- norm = sqrt(mx * mx + my * my + mz * mz);
- if (norm == 0.0f) return; // handle NaN
- norm = 1.0f / norm; // use reciprocal for division
- mx *= norm;
- my *= norm;
- mz *= norm;
-
- // Reference direction of Earth's magnetic field
- hx = 2.0f * mx * (0.5f - q3q3 - q4q4) + 2.0f * my * (q2q3 - q1q4) + 2.0f * mz * (q2q4 + q1q3);
- hy = 2.0f * mx * (q2q3 + q1q4) + 2.0f * my * (0.5f - q2q2 - q4q4) + 2.0f * mz * (q3q4 - q1q2);
- bx = sqrt((hx * hx) + (hy * hy));
- bz = 2.0f * mx * (q2q4 - q1q3) + 2.0f * my * (q3q4 + q1q2) + 2.0f * mz * (0.5f - q2q2 - q3q3);
-
- // Estimated direction of gravity and magnetic field
- vx = 2.0f * (q2q4 - q1q3);
- vy = 2.0f * (q1q2 + q3q4);
- vz = q1q1 - q2q2 - q3q3 + q4q4;
- wx = 2.0f * bx * (0.5f - q3q3 - q4q4) + 2.0f * bz * (q2q4 - q1q3);
- wy = 2.0f * bx * (q2q3 - q1q4) + 2.0f * bz * (q1q2 + q3q4);
- wz = 2.0f * bx * (q1q3 + q2q4) + 2.0f * bz * (0.5f - q2q2 - q3q3);
+ void velocityUpdate(float ax, float ay, float az);
+
+ void readIMU();
+
+ void imuSetup();
+
+ accData_t getVelocityFromIMU();
+};
- // Error is cross product between estimated direction and measured direction of gravity
- ex = (ay * vz - az * vy) + (my * wz - mz * wy);
- ey = (az * vx - ax * vz) + (mz * wx - mx * wz);
- ez = (ax * vy - ay * vx) + (mx * wy - my * wx);
- if (Ki > 0.0f)
- {
- eInt[0] += ex; // accumulate integral error
- eInt[1] += ey;
- eInt[2] += ez;
- }
- else
- {
- eInt[0] = 0.0f; // prevent integral wind up
- eInt[1] = 0.0f;
- eInt[2] = 0.0f;
- }
-
- // Apply feedback terms
- gx = gx + Kp * ex + Ki * eInt[0];
- gy = gy + Kp * ey + Ki * eInt[1];
- gz = gz + Kp * ez + Ki * eInt[2];
-
- // Integrate rate of change of quaternion
- pa = q2;
- pb = q3;
- pc = q4;
- q1 = q1 + (-q2 * gx - q3 * gy - q4 * gz) * (0.5f * deltat);
- q2 = pa + (q1 * gx + pb * gz - pc * gy) * (0.5f * deltat);
- q3 = pb + (q1 * gy - pa * gz + pc * gx) * (0.5f * deltat);
- q4 = pc + (q1 * gz + pa * gy - pb * gx) * (0.5f * deltat);
-
- // Normalise quaternion
- norm = sqrt(q1 * q1 + q2 * q2 + q3 * q3 + q4 * q4);
- norm = 1.0f / norm;
- q[0] = q1 * norm;
- q[1] = q2 * norm;
- q[2] = q3 * norm;
- q[3] = q4 * norm;
-
- }
- };
#endif
\ No newline at end of file
--- a/main.cpp Sat Mar 28 15:28:19 2020 +0000
+++ b/main.cpp Sat Apr 11 08:15:48 2020 +0000
@@ -2,6 +2,8 @@
#include "mbed_events.h"
#include "MPU9250.h"
+#define SAMPLE_TIME 100
+
DigitalOut led1(LED1);
InterruptIn sw(USER_BUTTON);
@@ -15,13 +17,6 @@
//-----------------------------------------------------
//IMU
-float sum = 0;
-uint32_t sumCount = 0;
-char buffer[14];
-
-MPU9250 mpu9250;
-Timer t;
-Serial pc(USBTX, USBRX); // tx, rx
//-----------------------------------------------------
void rise_handler(void)
@@ -42,205 +37,20 @@
led1 = !led1;
}
-void readIMU()
-{
- while(read_imu_isrunning) {
- pc.printf("in thread readIMU\n\r");
- // If intPin goes high, all data registers have new data
- if(mpu9250.readByte(MPU9250_ADDRESS, INT_STATUS) & 0x01) { // On interrupt, check if data ready interrupt
-
- mpu9250.readAccelData(accelCount); // Read the x/y/z adc values
- // 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];
-
- mpu9250.readGyroData(gyroCount); // Read the x/y/z adc values
- // 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];
-
- mpu9250.readMagData(magCount); // Read the x/y/z adc values
- // Calculate the magnetometer values in milliGauss
- // Include factory calibration per data sheet and user environmental corrections
- mx = (float)magCount[0]*mRes*magCalibration[0] - magbias[0]; // get actual magnetometer value, this depends on scale being set
- my = (float)magCount[1]*mRes*magCalibration[1] - magbias[1];
- mz = (float)magCount[2]*mRes*magCalibration[2] - magbias[2];
- }
-
- Now = t.read_us();
- deltat = (float)((Now - lastUpdate)/1000000.0f) ; // set integration time by time elapsed since last filter update
- lastUpdate = Now;
-
- sum += deltat;
- sumCount++;
-
-// if(lastUpdate - firstUpdate > 10000000.0f) {
-// beta = 0.04; // decrease filter gain after stabilized
-// zeta = 0.015; // increasey bias drift gain after stabilized
-// }
-
- // Pass gyro rate as rad/s
- mpu9250.MadgwickQuaternionUpdate(ax, ay, az, gx*PI/180.0f, gy*PI/180.0f, gz*PI/180.0f, my, mx, mz);
- //mpu9250.MahonyQuaternionUpdate(ax, ay, az, gx*PI/180.0f, gy*PI/180.0f, gz*PI/180.0f, my, mx, mz);
-
- // Serial print and/or display at 0.5 s rate independent of data rates
- delt_t = t.read_ms() - _count;
- if (delt_t > 50) { // update LCD once per half-second independent of read rate
-
- /*pc.printf("ax = %f", 1000*ax);
- pc.printf(" ay = %f", 1000*ay);
- pc.printf(" az = %f mg\n\r", 1000*az);
-
- pc.printf("gx = %f", gx);
- pc.printf(" gy = %f", gy);
- pc.printf(" gz = %f deg/s\n\r", gz);
-
- pc.printf("gx = %f", mx);
- pc.printf(" gy = %f", my);
- pc.printf(" gz = %f mG\n\r", mz);*/
-
- tempCount = mpu9250.readTempData(); // Read the adc values
- temperature = ((float) tempCount) / 333.87f + 21.0f; // Temperature in degrees Centigrade
- //pc.printf(" temperature = %f C\n\r", temperature);
-
- /*pc.printf("q0 = %f\n\r", q[0]);
- pc.printf("q1 = %f\n\r", q[1]);
- pc.printf("q2 = %f\n\r", q[2]);
- pc.printf("q3 = %f\n\r", q[3]);*/
-
- /* lcd.clear();
- lcd.printString("MPU9250", 0, 0);
- lcd.printString("x y z", 0, 1);
- sprintf(buffer, "%d %d %d mg", (int)(1000.0f*ax), (int)(1000.0f*ay), (int)(1000.0f*az));
- lcd.printString(buffer, 0, 2);
- sprintf(buffer, "%d %d %d deg/s", (int)gx, (int)gy, (int)gz);
- lcd.printString(buffer, 0, 3);
- sprintf(buffer, "%d %d %d mG", (int)mx, (int)my, (int)mz);
- lcd.printString(buffer, 0, 4);
- */
- // Define output variables from updated quaternion---these are Tait-Bryan angles, commonly used in aircraft orientation.
- // In this coordinate system, the positive z-axis is down toward Earth.
- // Yaw is the angle between Sensor x-axis and Earth magnetic North (or true North if corrected for local declination, looking down on the sensor positive yaw is counterclockwise.
- // Pitch is angle between sensor x-axis and Earth ground plane, toward the Earth is positive, up toward the sky is negative.
- // Roll is angle between sensor y-axis and Earth ground plane, y-axis up is positive roll.
- // These arise from the definition of the homogeneous rotation matrix constructed from quaternions.
- // Tait-Bryan angles as well as Euler angles are non-commutative; that is, the get the correct orientation the rotations must be
- // applied in the correct order which for this configuration is yaw, pitch, and then roll.
- // For more see http://en.wikipedia.org/wiki/Conversion_between_quaternions_and_Euler_angles which has additional links.
- 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]);
- pitch = -asin(2.0f * (q[1] * q[3] - q[0] * q[2]));
- 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]);
- pitch *= 180.0f / PI;
- yaw *= 180.0f / PI;
- yaw -= 2.93f; // Declination at 8572 Berg TG: +2° 56'
- roll *= 180.0f / PI;
-
- pc.printf("Yaw, Pitch, Roll: %f %f %f\n\r", yaw, pitch, roll);
- //pc.printf("average rate = %f\n\r", (float) sumCount/sum);
-// sprintf(buffer, "YPR: %f %f %f", yaw, pitch, roll);
-// lcd.printString(buffer, 0, 4);
-// sprintf(buffer, "rate = %f", (float) sumCount/sum);
-// lcd.printString(buffer, 0, 5);
-
- myled= !myled;
- _count = t.read_ms();
-
- if(_count > 1<<21) {
- t.start(); // start the timer over again if ~30 minutes has passed
- _count = 0;
- deltat= 0;
- lastUpdate = t.read_us();
- }
- sum = 0;
- sumCount = 0;
- }
- }
-}
-
-void imuSetup()
-{
- read_imu_isrunning = true;
- //Set up I2C
- i2c.frequency(400000); // use fast (400 kHz) I2C
-
- pc.printf("CPU SystemCoreClock is %d Hz\r\n", SystemCoreClock);
-
- t.start();
-// lcd.setBrightness(0.05);
- // Read the WHO_AM_I register, this is a good test of communication
- uint8_t whoami = mpu9250.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");
- sprintf(buffer, "0x%x", whoami);
- wait(1);
-
- mpu9250.resetMPU9250(); // Reset registers to default in preparation for device calibration
- mpu9250.MPU9250SelfTest(SelfTest); // 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]);
- mpu9250.calibrateMPU9250(gyroBias, accelBias); // 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);
- mpu9250.initMPU9250();
- pc.printf("MPU9250 initialized for active data mode....\n\r"); // Initialize device for active mode read of acclerometer, gyroscope, and temperature
- mpu9250.initAK8963(magCalibration);
- pc.printf("AK8963 initialized for active data mode....\n\r"); // Initialize device for active mode read of magnetometer
- 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);
- sprintf(buffer, "WHO_AM_I 0x%x", whoami);
-
- while(1) {
- // Loop forever if communication doesn't happen
- pc.printf("commication not happening\n\r");
- }
- }
-
- mpu9250.getAres(); // Get accelerometer sensitivity
- mpu9250.getGres(); // Get gyro sensitivity
- mpu9250.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);
- magbias[0] = +470.; // User environmental x-axis correction in milliGauss, should be automatically calculated
- magbias[1] = +120.; // User environmental x-axis correction in milliGauss
- magbias[2] = +125.; // User environmental x-axis correction in milliGauss
-}
int main()
{
- pc.baud(9600);
- imuSetup();
- imuthread.start(readIMU);
+ //pc.baud(9600);
+ //imuSetup();
+ //imuthread.start(readIMU);
// Request the shared queue
EventQueue *queue = mbed_event_queue();
- printf("Starting in context %p\r\n", Thread::gettid());
+ //printf("Starting in context %p\r\n", Thread::gettid());
// The 'rise' handler will execute in IRQ context
sw.rise(queue->event(rise_handler));