upm/examples/c++/mmc35240.cxx

/*
 * Author: Lay, Kuan Loon <kuan.loon.lay@intel.com>
 * Copyright (c) 2016 Intel Corporation.
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
#include <iostream>
#include <unistd.h>
#include <signal.h>
#include <math.h>
#include "mmc35240.hpp"

using namespace std;

int shouldRun = true;
upm::MMC35240* magnetometer;

void
sig_handler(int signo)
{
    if (signo == SIGINT)
        shouldRun = false;
}

void
data_callback(char* data, void* args)
{
    float x, y, z;
    double azimuth;
    int level;
    magnetometer->extract3Axis(data, &x, &y, &z);
    /* calibrated level
     * UNRELIABLE = 0
     * ACCURACY_LOW = 1
     * ACCURACY_MEDIUM = 2
     * ACCURACY_HIGH = >=3
     */
    level = magnetometer->getCalibratedLevel();

    if ((x == 0) && (y == 0)) {
        cout << "Point (0, 0) is invalid!\n" << endl;
        return;
    }

    if (x == 0) {
        if (y > 0)
            azimuth = 0;
        else
            azimuth = 180;
    } else if (y == 0) {
        if (x > 0)
            azimuth = 90;
        else
            azimuth = 270;
    } else {
        if (x > 0)
            azimuth = 90 - atan(y / x) * 180 / M_PI;
        else
            azimuth = 270 - atan(y / x) * 180 / M_PI;
    }

    cout << "[Calibrated Level:" << level << ']' << "[Azimuth:" << (int) (360 - azimuth) << ']'
         << '\t' << (int) x << '\t' << (int) y << '\t' << (int) z << "[uT]" << endl;
}

int
main()
{
    signal(SIGINT, sig_handler);
    //! [Interesting]
    // Instantiate a MMC35240 Magnetic Sensor on iio device 5. This configuration is a reference and
    // should be changed per platform/board type.
    magnetometer = new upm::MMC35240(5);
    // Kernel driver does not allow changing the value of scale at run-time, default scale is
    // 0.001000
    magnetometer->setScale(0.001000);
    // Available sampling frequency are 1.5, 13, 25, 50
    magnetometer->setSamplingFrequency(25.000000);
    magnetometer->enable3AxisChannel();
    magnetometer->installISR(data_callback, NULL);
    magnetometer->enableBuffer(16);

    while (shouldRun) {
        sleep(1);
    }
    magnetometer->disableBuffer();

    //! [Interesting]
    cout << "Exiting" << endl;

    delete magnetometer;

    return 0;
}