Diff: main.cpp
- Revision:
- 0:648796e4886d
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+++ b/main.cpp Mon Apr 08 20:56:48 2019 +0000
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+/* MPU9150 Basic Example Code
+ by: Kris Winer
+ date: April 1, 2014
+ license: Beerware - Use this code however you'd like. If you
+ find it useful you can buy me a beer some time.
+
+ Demonstrate basic MPU-9150 functionality including parameterizing the register addresses, initializing the sensor,
+ getting properly scaled accelerometer, gyroscope, and magnetometer data out. Added display functions to
+ allow display to on breadboard monitor. Addition of 9 DoF sensor fusion using open source Madgwick and
+ Mahony filter algorithms. Sketch runs on the 3.3 V 8 MHz Pro Mini and the Teensy 3.1.
+
+ SDA and SCL should have external pull-up resistors (to 3.3V).
+ 10k resistors are on the EMSENSR-9250 breakout board.
+
+ Hardware setup:
+ MPU9150 Breakout --------- Arduino
+ VDD ---------------------- 3.3V
+ VDDI --------------------- 3.3V
+ SDA ----------------------- A4
+ SCL ----------------------- A5
+ GND ---------------------- GND
+
+ Note: The MPU9150 is an I2C sensor and uses the Arduino Wire library.
+ Because the sensor is not 5V tolerant, we are using a 3.3 V 8 MHz Pro Mini or a 3.3 V Teensy 3.1.
+ We have disabled the internal pull-ups used by the Wire library in the Wire.h/twi.c utility file.
+ We are also using the 400 kHz fast I2C mode by setting the TWI_FREQ to 400000L /twi.h utility file.
+ */
+
+
+#include "mbed.h"
+#include "MPU9150.h"
+
+float sum = 0;
+uint32_t sumCount = 0, mcount = 0;
+char buffer[14];
+
+ MPU9150 MPU9150;
+
+ Timer t;
+
+ Serial pc(USBTX, USBRX); // tx, rx
+
+
+
+int main()
+{
+ pc.baud(9600);
+
+ //Set up I2C
+ i2c.frequency(400000); // use fast (400 kHz) I2C
+
+ pc.printf("CPU SystemCoreClock is %d Hz\r\n", SystemCoreClock);
+
+ t.start();
+
+ // Read the WHO_AM_I register, this is a good test of communication
+ uint8_t whoami = MPU9150.readByte(MPU9150_ADDRESS, WHO_AM_I_MPU9150); // Read WHO_AM_I register for MPU-9250
+ pc.printf("I AM 0x%x\n\r", whoami); pc.printf("I SHOULD BE 0x68\n\r");
+
+ if (whoami == 0x68) // WHO_AM_I should be 0x68
+ {
+ pc.printf("MPU9150 WHO_AM_I is 0x%x\n\r", whoami);
+ pc.printf("MPU9150 is online...\n\r");
+ sprintf(buffer, "0x%x", whoami);
+ wait(1);
+
+ MPU9150.MPU9150SelfTest(SelfTest);
+ 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]);
+ wait(1);
+ MPU9150.resetMPU9150(); // Reset registers to default in preparation for device calibration
+ MPU9150.calibrateMPU9150(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(1);
+ MPU9150.initMPU9150();
+ pc.printf("MPU9150 initialized for active data mode....\n\r"); // Initialize device for active mode read of acclerometer, gyroscope, and temperature
+ MPU9150.initAK8975A(magCalibration);
+ pc.printf("AK8975 initialized for active data mode....\n\r"); // Initialize device for active mode read of magnetometer
+ }
+ else
+ {
+ pc.printf("Could not connect to MPU9150: \n\r");
+ pc.printf("%#x \n", whoami);
+
+ sprintf(buffer, "WHO_AM_I 0x%x", whoami);
+
+ while(1) ; // Loop forever if communication doesn't happen
+ }
+
+ uint8_t MagRate = 10; // set magnetometer read rate in Hz; 10 to 100 (max) Hz are reasonable values
+ MPU9150.getAres(); // Get accelerometer sensitivity
+ MPU9150.getGres(); // Get gyro sensitivity
+ mRes = 10.*1229./4096.; // Conversion from 1229 microTesla full scale (4096) to 12.29 Gauss full scale
+ // So far, magnetometer bias is calculated and subtracted here manually, should construct an algorithm to do it automatically
+ // like the gyro and accelerometer biases
+ magbias[0] = -5.; // User environmental x-axis correction in milliGauss
+ magbias[1] = -95.; // User environmental y-axis correction in milliGauss
+ magbias[2] = -260.; // User environmental z-axis correction in milliGauss
+
+
+ while(1) {
+
+ // If intPin goes high, all data registers have new data
+ if(MPU9150.readByte(MPU9150_ADDRESS, INT_STATUS) & 0x01) { // On interrupt, check if data ready interrupt
+
+ MPU9150.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];
+
+ MPU9150.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];
+
+ mcount++;
+ if (mcount > 200/MagRate) { // this is a poor man's way of setting the magnetometer read rate (see below)
+ MPU9150.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];
+ mcount = 0;
+ }
+ }
+
+ 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
+// MPU9150.MadgwickQuaternionUpdate(ax, ay, az, gx*PI/180.0f, gy*PI/180.0f, gz*PI/180.0f, my, mx, mz);
+ MPU9150.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() - cont;
+ if (delt_t > 500) { // 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 = MPU9150.readTempData(); // Read the adc values
+ temperature = ((float) tempCount) / 340.0f + 36.53f; // 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("MPU9150", 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 -= 13.8f; // Declination at Danville, California is 13 degrees 48 minutes and 47 seconds on 2014-04-04
+ 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;
+ cont = t.read_ms();
+
+ if(cont > 1<<21) {
+ t.start(); // start the timer over again if ~30 minutes has passed
+ cont = 0;
+ deltat= 0;
+ lastUpdate = t.read_us();
+ }
+ sum = 0;
+ sumCount = 0;
+}
+}
+
+ }
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