File content as of revision 1:4fb66612cb9c:

 #include    "mbed.h"
 #include    "math.h"
 #include    "BNO055.h"
 
 #define PI 3.141593
 
 Serial pc(USBTX,USBRX);
 BNO055 imu(D14, D15);         // SDA, SCL 
 
 double y;
 double x;
 double z;
 double angleToNorth;
 double result;
// BNO055_ID_INF_TypeDef bno055_id_inf;
// BNO055_EULER_TypeDef  euler_angles;

 double getAngleToNorth (double x, double y, double result) {
        if (y > 0) {
            return 90.0 - atan(result) * 180/PI;  
        }      
        else if (y < 0) {
            return  270.0 - atan(result) * 180/PI;
        }
        else if (y == 0 && x <= 0) {
            return 180;
        }
        else if (y == 0 && x > 0) {
            return 0;
        }
} 
 
void getValues() {
    imu.get_accel();
    imu.get_gyro();
    imu.get_mag();
}
 
void printInfo() {
    //pc.printf("BNO055 found\r\n\r\n");
    pc.printf("Chip          ID: %0z\r\n",imu.ID.id);
    pc.printf("Accelerometer ID: %0z\r\n",imu.ID.accel);
    pc.printf("Gyroscope     ID: %0z\r\n",imu.ID.gyro);
    pc.printf("Magnetometer  ID: %0z\r\n\r\n",imu.ID.mag);
    pc.printf("Firmware version v%d.%0d\r\n",imu.ID.sw[0],imu.ID.sw[1]);
    pc.printf("Bootloader version v%d\r\n\r\n",imu.ID.bootload);
}
 
void setup() {
    imu.reset();
    imu.set_accel_units(MPERSPERS);
    imu.setmode(OPERATION_MODE_AMG);
    imu.read_calibration_data();
    imu.write_calibration_data();
    imu.set_angle_units(DEGREES);
}

void printAccel() {
    pc.printf("acceleration: x %f\ty %f\tz %f \r\n", imu.accel.x, imu.accel.y + .25, imu.accel.z);
}

void printGyro() {
    pc.printf("gyroscope: x %f\ty %f\tz %f \r\n", imu.gyro.x, imu.gyro.y, imu.gyro.z);
}

void printMag() {
    pc.printf("magnometer { x: %d\t y: %d\t z: %d }\r\n", imu.mag.x, imu.mag.y, imu.mag.z);
}

void printValues() {
    printAccel();
    printGyro();
    printMag();
}

void checkAvail() {
    while (imu.check() == 0){
        pc.printf("Bosch BNO055 is NOT available!!\r\n");
        wait_ms(200);
    }
    
    pc.printf("Bosch Sensortec BNO055 available \r\n");//" __DATE__ "/" __TIME__ "\r\n");
}

int main() {

    setup();
    //pc.printf("Bosch Sensortec BNO055 test program on \r\n");//" __DATE__ "/" __TIME__ "\r\n"); 
    checkAvail();
    printInfo();

    while (1) {
        getValues();
        printMag();
        
        result = (double) imu.mag.x / imu.mag.y;
        angleToNorth = getAngleToNorth(imu.mag.x, imu.mag.y, result);      
        
        pc.printf("it is pointing %f angle from north \r\n\n", angleToNorth); 
        wait_us(200);
    }
}