File content as of revision 0:7eb9e18d5839:

#include "mbed.h"
#include "MPU6050.h"
#include "FXOS8700CQ.h"

float sum = 0;
uint32_t sumCount = 0;
 
MPU6050 mpu6050;
FXOS8700CQ fxos(PTE25, PTE24, FXOS8700CQ_SLAVE_ADDR1); // SDA, SCL, (addr << 1)

Timer t;

InterruptIn fxos_int2(PTC13); // should just be the Data-Ready interrupt
bool fxos_int2_triggered = false; // Interrupt status flags and data
 
SRAWDATA accel_data; // Storage for the data from the sensor
SRAWDATA magn_data;

Serial pc(USBTX, USBRX); // tx, rx

void trigger_fxos_int2(void){
    fxos_int2_triggered = true;
}
 
void print_reading(){
    pc.printf("A X:%5d,Y:%5d,Z:%5d   M X:%5d,Y:%5d,Z:%5d\r\n",
              accel_data.x, accel_data.y, accel_data.z,
              magn_data.x, magn_data.y, magn_data.z);
}

int main(){
  t.start();
  pc.baud(115200); // 200Hz x line of output data!  
  
  printf("\r\n\nFXOS8700Q Who Am I= %X\r\n", fxos.get_whoami());
     
  fxos_int2.fall(&trigger_fxos_int2); // Iterrupt for active-low interrupt line from FXOS
  fxos.enable();
  
  pc.printf("Started data collection. Accelerometer at max %dg.\r\n",
  fxos.get_accel_scale());
 
  fxos.get_data(&accel_data, &magn_data); // clear interrupt from device
  fxos_int2_triggered = false; // un-trigger
  
  //Set up I2C
  i2c.frequency(400000);  // use fast (400 kHz) I2C   
    
  // Read the WHO_AM_I register, this is a good test of communication
  uint8_t whoami = mpu6050.readByte(MPU6050_ADDRESS, WHO_AM_I_MPU6050);  // Read WHO_AM_I register for MPU-6050
  pc.printf("I AM 0x%x\n\r", whoami); pc.printf("I SHOULD BE 0x68\n\r");
  
  if (whoami == 0x68){ // WHO_AM_I should always be 0x68  
    pc.printf("MPU6050 is online...");
    wait(1);
    
    mpu6050.MPU6050SelfTest(SelfTest); // Start by performing self test and reporting values
    pc.printf("x-axis self test: acceleration trim within : "); pc.printf("%f", SelfTest[0]); pc.printf("% of factory value \n\r");
    pc.printf("y-axis self test: acceleration trim within : "); pc.printf("%f", SelfTest[1]); pc.printf("% of factory value \n\r");
    pc.printf("z-axis self test: acceleration trim within : "); pc.printf("%f", SelfTest[2]); pc.printf("% of factory value \n\r");
    pc.printf("x-axis self test: gyration trim within : "); pc.printf("%f", SelfTest[3]); pc.printf("% of factory value \n\r");
    pc.printf("y-axis self test: gyration trim within : "); pc.printf("%f", SelfTest[4]); pc.printf("% of factory value \n\r");
    pc.printf("z-axis self test: gyration trim within : "); pc.printf("%f", SelfTest[5]); pc.printf("% of factory value \n\r");
    wait(1);
 
    if(SelfTest[0] < 1.0f && SelfTest[1] < 1.0f && SelfTest[2] < 1.0f && SelfTest[3] < 1.0f && SelfTest[4] < 1.0f && SelfTest[5] < 1.0f){
        mpu6050.resetMPU6050(); // Reset registers to default in preparation for device calibration
        mpu6050.calibrateMPU6050(gyroBias, accelBias); // Calibrate gyro and accelerometers, load biases in bias registers  
        mpu6050.initMPU6050(); pc.printf("MPU6050 initialized for active data mode....\n\r"); // Initialize device for active mode read of acclerometer, gyroscope, and temperature
        wait(2);
    }else pc.printf("Device did not the pass self-test!\n\r");
    }else{
        pc.printf("Could not connect to MPU6050: \n\r");
        pc.printf("%#x \n",  whoami);
        while(1) ; // Loop forever if communication doesn't happen
    }
 
 while(1){
  // If data ready bit set, all data registers have new data
  if(mpu6050.readByte(MPU6050_ADDRESS, INT_STATUS) & 0x01) {  // check if data ready interrupt
    mpu6050.readAccelData(accelCount);  // Read the x/y/z adc values
    mpu6050.getAres();
    
    // 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];  
   
    mpu6050.readGyroData(gyroCount);  // Read the x/y/z adc values
    mpu6050.getGres();
 
    // 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];   
 
    tempCount = mpu6050.readTempData();  // Read the x/y/z adc values
    temperature = (tempCount) / 340. + 36.53; // Temperature in degrees Centigrade
   }
   
   if(fxos_int2_triggered){
           fxos_int2_triggered = false; // un-trigger
           fxos.get_data(&accel_data, &magn_data);
   }  
   
    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
    mpu6050.MadgwickQuaternionUpdate(ax, ay, az, gx*PI/180.0f, gy*PI/180.0f, gz*PI/180.0f);
 
    // Serial print and/or display at 0.5 s rate independent of data rates
    delt_t = t.read_ms() - count;

    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(" 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]);      

    
    
  // 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; 
    roll  *= 180.0f / PI;
 
//    pc.printf("Yaw, Pitch, Roll: \n\r");
//    pc.printf("%f", yaw);
//    pc.printf(", ");
//    pc.printf("%f", pitch);
//    pc.printf(", ");
//    pc.printf("%f\n\r", roll);
//    pc.printf("average rate = "); pc.printf("%f", (sumCount/sum)); pc.printf(" Hz\n\r");
 
     pc.printf("Yaw, Pitch, Roll: %f %f %f\n\r", yaw, pitch, roll);
     pc.printf("average rate = %f\n\r", (float) sumCount/sum);
 
    count = t.read_ms(); 
    sum = 0;
    sumCount = 0; 
}
}