LibrePilot/flight/modules/Example/examplemodperiodic.c

/**
 ******************************************************************************
 *
 * @file       examplemodperiodic.c
 * @author     The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010.
 * @brief      Example module to be used as a template for actual modules.
 *             Threaded periodic version.
 *
 * @see        The GNU Public License (GPL) Version 3
 *
 *****************************************************************************/
/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
 * for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

/**
 * Input object: ExampleSettings
 * Output object: ExampleObject2
 *
 * This module will periodically update the value of the ExampleObject object.
 * The module settings can configure how the ExampleObject is manipulated.
 *
 * The module executes in its own thread in this example.
 *
 * UAVObjects are automatically generated by the UAVObjectGenerator from
 * the object definition XML file.
 *
 * Modules have no API, all communication to other modules is done through UAVObjects.
 * However modules may use the API exposed by shared libraries.
 * See the OpenPilot wiki for more details.
 * http://www.openpilot.org/OpenPilot_Application_Architecture
 *
 */

#include "openpilot.h"
#include "examplemodperiodic.h"
#include "exampleobject2.h" // object that will be updated by the module
#include "examplesettings.h" // object holding module settings

// Private constants
#define STACK_SIZE    configMINIMAL_STACK_SIZE
#define TASK_PRIORITY (tskIDLE_PRIORITY + 1)

// Private types

// Private variables
static xTaskHandle taskHandle;

// Private functions
static void exampleTask(void *parameters);

/**
 * Initialise the module, called on startup
 * \returns 0 on success or -1 if initialisation failed
 */
int32_t ExampleModPeriodicInitialize()
{
    // Start main task
    xTaskCreate(exampleTask, (signed char *)"ExamplePeriodic", STACK_SIZE, NULL, TASK_PRIORITY, &taskHandle);

    return 0;
}

/**
 * Module thread, should not return.
 */
static void exampleTask(__attribute__((unused)) void *parameters)
{
    ExampleSettingsData settings;
    ExampleObject2Data data;
    int32_t step;
    portTickType lastSysTime;

    // Main task loop
    lastSysTime = xTaskGetTickCount();
    while (1) {
        // Update settings with latest value
        ExampleSettingsGet(&settings);

        // Get the object data
        ExampleObject2Get(&data);

        // Determine how to update the data
        if (settings.StepDirection == EXAMPLESETTINGS_STEPDIRECTION_UP) {
            step = settings.StepSize;
        } else {
            step = -settings.StepSize;
        }

        // Update the data
        data.Field1    += step;
        data.Field2    += step;
        data.Field3    += step;
        data.Field4[0] += step;
        data.Field4[1] += step;

        // Update the ExampleObject, after this function is called
        // notifications to any other modules listening to that object
        // will be sent and the GCS object will be updated through the
        // telemetry link. All operations will take place asynchronously
        // and the following call will return immediately.
        ExampleObject2Set(&data);

        // Since this module executes at fixed time intervals, we need to
        // block the task until it is time for the next update.
        // The settings field is in ms, to convert to RTOS ticks we need
        // to divide by portTICK_RATE_MS.
        vTaskDelayUntil(&lastSysTime, settings.UpdatePeriod / portTICK_RATE_MS);
    }
}