Diff: attitude.h

Revision:

1:852156b5cca1

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/attitude.h	Mon Apr 02 10:18:44 2018 +0000
@@ -0,0 +1,81 @@
+#include "MPU9250.h"
+
+MPU9250 mpu9250;
+
+Timer t;
+
+void attitude_setup(void)
+{
+    i2c.frequency(400000);  // use fast (400 kHz) I2C
+    
+    t.start();
+
+    // 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
+    
+
+    if (whoami == 0x73) { // WHO_AM_I should always be 0x68
+        wait(1);
+        mpu9250.resetMPU9250(); // Reset registers to default in preparation for device calibration
+        mpu9250.calibrateMPU9250(gyroBias, accelBias); // Calibrate gyro and accelerometers, load biases in bias registers
+        wait(2);
+        mpu9250.initMPU9250();
+        mpu9250.initAK8963(magCalibration);
+        wait(2);
+    } else while(1) ; // Loop forever if communication doesn't happen
+
+    mpu9250.getAres(); // Get accelerometer sensitivity
+    mpu9250.getGres(); // Get gyro sensitivity
+    mpu9250.getMres(); // Get magnetometer sensitivity
+
+    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 attitude_get(void)
+{
+    // 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;
+
+        // 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);
+
+        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;
+
+        return 0;
+    }
+    return -1;
+}
+