main.cpp

00001 #include "mbed.h"
00002 #include "MPU9250.h"
00003 
00004 float sum = 0;
00005 uint32_t sumCount = 0;
00006 char buffer[14];
00007 float yaw_an = 0;
00008 int16_t gz_tmp;
00009 
00010 MPU9250 mpu9250;
00011 
00012 Timer t;
00013 
00014 Serial pc(USBTX, USBRX); // tx, rx
00015   
00016 
00017         
00018 int main()
00019 {
00020     pc.baud(115200);  
00021     
00022     //Set up I2C
00023     i2c.frequency(400000);  // use fast (400 kHz) I2C  
00024     
00025     t.start();        
00026     
00027     
00028     
00029     // Read the WHO_AM_I register, this is a good test of communication
00030     uint8_t whoami = mpu9250.readByte(MPU9250_ADDRESS, WHO_AM_I_MPU9250);  // Read WHO_AM_I register for MPU-9250
00031     pc.printf("I AM 0x%x\n\r", whoami); pc.printf("I SHOULD BE 0x71\n\r");
00032     
00033     if (whoami == 0x71) // WHO_AM_I should always be 0x68
00034     {  
00035         pc.printf("MPU9250 WHO_AM_I is 0x%x\n\r", whoami);
00036         pc.printf("MPU9250 is online...\n\r");
00037         wait(1);
00038         
00039         mpu9250.resetMPU9250(); // Reset registers to default in preparation for device calibration
00040         mpu9250.MPU9250SelfTest(SelfTest); // Start by performing self test and reporting values
00041         pc.printf("x-axis self test: acceleration trim within : %f % of factory value\n\r", SelfTest[0]);  
00042         pc.printf("y-axis self test: acceleration trim within : %f % of factory value\n\r", SelfTest[1]);  
00043         pc.printf("z-axis self test: acceleration trim within : %f % of factory value\n\r", SelfTest[2]);  
00044         pc.printf("x-axis self test: gyration trim within : %f % of factory value\n\r", SelfTest[3]);  
00045         pc.printf("y-axis self test: gyration trim within : %f % of factory value\n\r", SelfTest[4]);  
00046         pc.printf("z-axis self test: gyration trim within : %f % of factory value\n\r", SelfTest[5]);  
00047         mpu9250.calibrateMPU9250(gyroBias, accelBias); // Calibrate gyro and accelerometers, load biases in bias registers  
00048         pc.printf("x gyro bias = %f\n\r", gyroBias[0]);
00049         pc.printf("y gyro bias = %f\n\r", gyroBias[1]);
00050         pc.printf("z gyro bias = %f\n\r", gyroBias[2]);
00051         pc.printf("x accel bias = %f\n\r", accelBias[0]);
00052         pc.printf("y accel bias = %f\n\r", accelBias[1]);
00053         pc.printf("z accel bias = %f\n\r", accelBias[2]);
00054         wait(2);
00055         mpu9250.initMPU9250(); 
00056         pc.printf("MPU9250 initialized for active data mode....\n\r"); // Initialize device for active mode read of acclerometer, gyroscope, and temperature
00057         mpu9250.initAK8963(magCalibration);
00058         pc.printf("AK8963 initialized for active data mode....\n\r"); // Initialize device for active mode read of magnetometer
00059         pc.printf("Accelerometer full-scale range = %f  g\n\r", 2.0f*(float)(1<<Ascale));
00060         pc.printf("Gyroscope full-scale range = %f  deg/s\n\r", 250.0f*(float)(1<<Gscale));
00061         if(Mscale == 0) pc.printf("Magnetometer resolution = 14  bits\n\r");
00062         if(Mscale == 1) pc.printf("Magnetometer resolution = 16  bits\n\r");
00063         if(Mmode == 2) pc.printf("Magnetometer ODR = 8 Hz\n\r");
00064         if(Mmode == 6) pc.printf("Magnetometer ODR = 100 Hz\n\r");
00065         wait(1);
00066     }
00067     else
00068     {
00069         pc.printf("Could not connect to MPU9250: \n\r");
00070         pc.printf("%#x \n",  whoami);
00071         
00072         while(1) ; // Loop forever if communication doesn't happen
00073     }
00074     
00075     mpu9250.getAres(); // Get accelerometer sensitivity
00076     mpu9250.getGres(); // Get gyro sensitivity
00077     mpu9250.getMres(); // Get magnetometer sensitivity
00078     pc.printf("Accelerometer sensitivity is %f LSB/g \n\r", 1.0f/aRes);
00079     pc.printf("Gyroscope sensitivity is %f LSB/deg/s \n\r", 1.0f/gRes);
00080     pc.printf("Magnetometer sensitivity is %f LSB/G \n\r", 1.0f/mRes);
00081 
00082     while(1) {
00083         
00084         // If intPin goes high, all data registers have new data
00085         if(mpu9250.readByte(MPU9250_ADDRESS, INT_STATUS) & 0x01) {  // On interrupt, check if data ready interrupt
00086         
00087             mpu9250.readAccelData(accelCount);  // Read the x/y/z adc values   
00088             // Now we'll calculate the accleration value into actual g's
00089             ax = (float)accelCount[0]*aRes - accelBias[0];  // get actual g value, this depends on scale being set
00090             ay = (float)accelCount[1]*aRes - accelBias[1];   
00091             az = (float)accelCount[2]*aRes - accelBias[2];  
00092             
00093             mpu9250.readGyroData(gyroCount);  // Read the x/y/z adc values
00094             // Calculate the gyro value into actual degrees per second
00095             gx = (float)gyroCount[0]*gRes - gyroBias[0];  // get actual gyro value, this depends on scale being set
00096             gy = (float)gyroCount[1]*gRes - gyroBias[1];  
00097             gz = (float)gyroCount[2]*gRes - gyroBias[2];   
00098             
00099             mpu9250.readMagData(magCount);  // Read the x/y/z adc values   
00100             // Calculate the magnetometer values in milliGauss
00101             // Include factory calibration per data sheet and user environmental corrections
00102             mx = (float)magCount[0]*mRes*magCalibration[0] - magbias[0];  // get actual magnetometer value, this depends on scale being set
00103             my = (float)magCount[1]*mRes*magCalibration[1] - magbias[1];  
00104             mz = (float)magCount[2]*mRes*magCalibration[2] - magbias[2];   
00105         }
00106         
00107         Now = t.read_us();
00108         deltat = (float)((Now - lastUpdate)/1000000.0f) ; // set integration time by time elapsed since last filter update
00109         lastUpdate = Now;
00110         gz_tmp = gz;
00111         yaw_an -= (float)gz_tmp * deltat;
00112         sum += deltat;
00113         
00114         sumCount++;
00115         
00116         //    if(lastUpdate - firstUpdate > 10000000.0f) {
00117         //     beta = 0.04;  // decrease filter gain after stabilized
00118         //     zeta = 0.015; // increasey bias drift gain after stabilized
00119         //   }
00120         
00121         // Pass gyro rate as rad/s
00122         mpu9250.MadgwickQuaternionUpdate(ax, ay, az, gx*PI/180.0f, gy*PI/180.0f, gz*PI/180.0f,  my,  mx, mz);
00123         //  mpu9250.MahonyQuaternionUpdate(ax, ay, az, gx*PI/180.0f, gy*PI/180.0f, gz*PI/180.0f, my, mx, mz);
00124         
00125         // Serial print and/or display at 0.5 s rate independent of data rates
00126         delt_t = t.read_ms() - count;
00127         if (delt_t > 500) { // update LCD once per half-second independent of read rate
00128         
00129             pc.printf("ax = %f", 1000*ax); 
00130             pc.printf(" ay = %f", 1000*ay); 
00131             pc.printf(" az = %f  mg\n\r", 1000*az); 
00132             
00133             pc.printf("gx = %f", gx); 
00134             pc.printf(" gy = %f", gy); 
00135             pc.printf(" gz = %f  deg/s\n\r", gz); 
00136             
00137             pc.printf("mx = %f", mx); 
00138             pc.printf(" my = %f", my); 
00139             pc.printf(" mz = %f  mG\n\r", mz); 
00140             
00141             tempCount = mpu9250.readTempData();  // Read the adc values
00142             temperature = ((float) tempCount) / 333.87f + 21.0f; // Temperature in degrees Centigrade
00143             pc.printf(" temperature = %f  C\n\r", temperature); 
00144             
00145             pc.printf("q0 = %f\n\r", q[0]);
00146             pc.printf("q1 = %f\n\r", q[1]);
00147             pc.printf("q2 = %f\n\r", q[2]);
00148             pc.printf("q3 = %f\n\r", q[3]);      
00149             
00150             // Define output variables from updated quaternion---these are Tait-Bryan angles, commonly used in aircraft orientation.
00151             // In this coordinate system, the positive z-axis is down toward Earth. 
00152             // 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.
00153             // Pitch is angle between sensor x-axis and Earth ground plane, toward the Earth is positive, up toward the sky is negative.
00154             // Roll is angle between sensor y-axis and Earth ground plane, y-axis up is positive roll.
00155             // These arise from the definition of the homogeneous rotation matrix constructed from quaternions.
00156             // Tait-Bryan angles as well as Euler angles are non-commutative; that is, the get the correct orientation the rotations must be
00157             // applied in the correct order which for this configuration is yaw, pitch, and then roll.
00158             // For more see http://en.wikipedia.org/wiki/Conversion_between_quaternions_and_Euler_angles which has additional links.
00159             //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]);   
00160             pitch = -asin(2.0f * (q[1] * q[3] - q[0] * q[2]));
00161             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]);
00162             pitch *= 180.0f / PI;
00163             //yaw   *= 180.0f / PI; 
00164             //yaw   -= 13.8f; // Declination at Danville, California is 13 degrees 48 minutes and 47 seconds on 2014-04-04
00165             yaw = yaw_an;
00166             roll  *= 180.0f / PI;
00167             
00168             pc.printf("Yaw, Pitch, Roll: %f %f %f\n\r", yaw, pitch, roll);
00169             pc.printf("average rate = %f\n\r", (float) sumCount/sum);
00170             
00171             myled= !myled;
00172             count = t.read_ms(); 
00173             
00174             if(count > 1<<21) {
00175                 t.stop();
00176                 t.reset();
00177                 t.start(); // start the timer over again if ~30 minutes has passed
00178                 count = 0;
00179                 deltat= 0;
00180                 lastUpdate = t.read_us();
00181             }
00182             sum = 0;
00183             sumCount = 0; 
00184         }
00185     }
00186 }