File content as of revision 4:7c9469bb52f4:

#include "mbed.h"
#include "kalman.c"
#include "x_nucleo_iks01a1.h"
#include <math.h>

#define PI             3.1415926535897932384626433832795
#define Rad2Dree       57.295779513082320876798154814105

/* Instantiate the expansion board */
static X_NUCLEO_IKS01A1 *mems_expansion_board = X_NUCLEO_IKS01A1::Instance(D14, D15);

/* Retrieve the composing elements of the expansion board */
static GyroSensor *gyroscope = mems_expansion_board->GetGyroscope();
static MotionSensor *accelerometer = mems_expansion_board->GetAccelerometer();
static MagneticSensor *magnetometer = mems_expansion_board->magnetometer;

Serial pc(USBTX, USBRX);

Timer GlobalTime;
Timer ProgramTimer;

float R;
double angle[3];
unsigned long timer;
long loopStartTime;
int32_t axesAcc[3];
int32_t axesGyro[3];
int32_t axesMag[3];

kalman filter_roll;
kalman filter_pitch;
kalman filter_yaw;

int main()
{
    pc.baud(9600);

//    GlobalTime.start();

    // Parameters ( R_angle, Q_gyro, Q_angle )
    kalman_init(&filter_pitch, R_matrix, Q_Gyro_matrix, Q_Accel_matrix);
    kalman_init(&filter_roll, R_matrix, Q_Gyro_matrix, Q_Accel_matrix);

    kalman_init(&filter_yaw, R_matrix, Q_Gyro_matrix, Q_Accel_matrix);


    ProgramTimer.start();
    loopStartTime = ProgramTimer.read_us();
    timer = loopStartTime;

    while(1) {
//    wait_ms(10);
        //Aquire new values for the Gyro and Acc
        accelerometer->Get_X_Axes(axesAcc);
        gyroscope->Get_G_Axes(axesGyro);
        magnetometer->Get_M_Axes(axesMag);

        //Calculate the resulting vector R from the 3 acc axes
        R = sqrt(std::pow((float)axesAcc[0] , 2) + std::pow((float)axesAcc[1] , 2) + std::pow((float)axesAcc[2] , 2));

        kalman_predict(&filter_roll, axesGyro[0],  (ProgramTimer.read_us() - timer));
        kalman_update(&filter_roll, acos(axesAcc[0]/R));

        kalman_predict(&filter_pitch, axesGyro[1],  (ProgramTimer.read_us() - timer));
        kalman_update(&filter_pitch, acos(axesAcc[1]/R));

        kalman_predict(&filter_yaw, axesGyro[2],  (ProgramTimer.read_us() - timer));
        kalman_update(&filter_yaw, acos(axesMag[2]/R));


        angle[0] = kalman_get_angle(&filter_roll);
        angle[1] = kalman_get_angle(&filter_pitch);
        //angle[2] = atan2((double)axesGyro[0],(double)axesGyro[1])*Rad2Dree;
        angle[2] = kalman_get_angle(&filter_yaw);
        atan2((double)axesAcc[0],(double)axesAcc[1])*Rad2Dree;

        timer = ProgramTimer.read_us();


        pc.printf("%.6f ;\t  %.6f;\t %.6f; \n\r", Rad2Dree * angle[0], Rad2Dree * angle[1], Rad2Dree * angle[2]);

    }
}