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LibrePilot/flight/modules/Example/examplemodcallback.c

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/**
******************************************************************************
*
* @file examplemodcallback.c
* @author The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010.
* @brief Example module to be used as a template for actual modules.
* Event callback 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 objects: ExampleObject1, ExampleSettings
* Output object: ExampleObject2
*
* This module executes in response to ExampleObject1 updates. When the
* module is triggered it will update the data of ExampleObject2.
*
* No threads are used 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 "exampleobject1.h" // object the module will listen for updates (input)
#include "exampleobject2.h" // object the module will update (output)
#include "examplesettings.h" // object holding module settings (input)
// Private constants
#define STACK_SIZE configMINIMAL_STACK_SIZE
#define CALLBACK_PRIORITY CALLBACK_PRIORITY_LOW
#define CBTASK_PRIORITY CALLBACK_TASKPRIORITY_AUXILIARY
// Private types
// Private variables
static DelayedCallbackInfo *cbinfo;
// Private functions
static void ObjectUpdatedCb(UAVObjEvent *ev);
static void DelayedCb();
/**
* Initialise the module, called on startup.
* \returns 0 on success or -1 if initialisation failed
*/
int32_t ExampleModCallbackInitialize()
{
// Listen for ExampleObject1 updates, connect a callback function
ExampleObject1ConnectCallback(&ObjectUpdatedCb);
cbinfo = DelayedCallbackCreate(&DelayedCb, CALLBACK_PRIORITY, CBTASK_PRIORITY, STACK_SIZE);
return 0;
}
/**
* This function is called each time ExampleObject1 is updated, this could be
* a local update or a remote update from the GCS. In this example the module
* does not have its own thread, the callbacks are executed from within the
* event thread. Because of that the callback execution time must be kept to
* a minimum.
*/
static void ObjectUpdatedCb(__attribute__((unused)) UAVObjEvent *ev)
{
DelayedCallbackDispatch(cbinfo);
}
/**
* This function is called by the DelayedCallbackScheduler when its execution
* has been requested. Callbacks scheduled for execution are executed in the
* same thread in a round robin fashion. The Dispatch function to reschedule
* execution can be called from within the Callback itself, in which case the
* re-run will be scheduled after all other callback with equal or higher
* priority have been executed. Like event callbacks, delayed callbacks are
* executed in the same thread context one at a time, therefore blocking IO
* functions or very long lasting calculations are prohibited. Unlike Event
* callbacks these callbacks run with a standard (IDLE+1) thread priority and
* do not block regular threads. They are therefore saver to use.
*/
static void DelayedCb();
ExampleSettingsData settings;
ExampleObject1Data data1;
ExampleObject2Data data2;
int32_t step;
// Update settings with latest value
ExampleSettingsGet(&settings);
// Get the input object
ExampleObject1Get(&data1);
// Determine how to update the output object
if (settings.StepDirection == EXAMPLESETTINGS_STEPDIRECTION_UP) {
step = settings.StepSize;
} else {
step = -settings.StepSize;
}
// Update data
data2.Field1 = data1.Field1 + step;
data2.Field2 = data1.Field2 + step;
data2.Field3 = data1.Field3 + step;
data2.Field4[0] = data1.Field4[0] + step;
data2.Field4[1] = data1.Field4[1] + step;
// Update the ExampleObject2, 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(&data2);
// call the module again 10 seconds later,
// even if the exampleobject has not been updated
DelayedCallbackSchedule(cbinfo, 10 * 1000, CALLBACK_UPDATEMODE_NONE);
}