flight/modules/Example/examplemodthread.c

   1 /**
   2  ******************************************************************************
   3  *
   4  * @file       examplemodthread.c
   5  * @author     The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010.
   6  * @brief      Example module to be used as a template for actual modules.
   7  *             Threaded version.
   8  *
   9  * @see        The GNU Public License (GPL) Version 3
  10  *
  11  *****************************************************************************/
  12 /*
  13  * This program is free software; you can redistribute it and/or modify
  14  * it under the terms of the GNU General Public License as published by
  15  * the Free Software Foundation; either version 3 of the License, or
  16  * (at your option) any later version.
  17  *
  18  * This program is distributed in the hope that it will be useful, but
  19  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  20  * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
  21  * for more details.
  22  *
  23  * You should have received a copy of the GNU General Public License along
  24  * with this program; if not, write to the Free Software Foundation, Inc.,
  25  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  26  */
  27
  28 /**
  29  * Input objects: ExampleObject1, ExampleSettings
  30  * Output object: ExampleObject2
  31  *
  32  * This module executes in response to ExampleObject1 updates. When the
  33  * module is triggered it will update the data of ExampleObject2.
  34  *
  35  * The module executes in its own thread in this example.
  36  *
  37  * UAVObjects are automatically generated by the UAVObjectGenerator from
  38  * the object definition XML file.
  39  *
  40  * Modules have no API, all communication to other modules is done through UAVObjects.
  41  * However modules may use the API exposed by shared libraries.
  42  * See the OpenPilot wiki for more details.
  43  * http://www.openpilot.org/OpenPilot_Application_Architecture
  44  */
  45
  46 #include "openpilot.h"
  47 #include "examplemodthread.h"
  48 #include "exampleobject1.h" // object the module will listen for updates (input)
  49 #include "exampleobject2.h" // object the module will update (output)
  50 #include "examplesettings.h" // object holding module settings (input)
  51
  52 // Private constants
  53 #define MAX_QUEUE_SIZE 20
  54 #define STACK_SIZE     configMINIMAL_STACK_SIZE
  55 #define TASK_PRIORITY  (tskIDLE_PRIORITY + 1)
  56
  57 // Private types
  58
  59 // Private variables
  60 static xQueueHandle queue;
  61 static xTaskHandle taskHandle;
  62
  63 // Private functions
  64 static void exampleTask(void *parameters);
  65
  66 /**
  67  * Initialise the module, called on startup
  68  * \returns 0 on success or -1 if initialisation failed
  69  */
  70 int32_t ExampleModThreadInitialize()
  71 {
  72     // Create object queue
  73     queue = xQueueCreate(MAX_QUEUE_SIZE, sizeof(UAVObjEvent));
  74
  75     // Listen for ExampleObject1 updates
  76     ExampleObject1ConnectQueue(queue);
  77
  78     // Start main task
  79     xTaskCreate(exampleTask, (signed char *)"ExampleThread", STACK_SIZE, NULL, TASK_PRIORITY, &taskHandle);
  80
  81     return 0;
  82 }
  83
  84 /**
  85  * Module thread, should not return.
  86  */
  87 static void exampleTask(__attribute__((unused)) void *parameters)
  88 {
  89     UAVObjEvent ev;
  90     ExampleSettingsData settings;
  91     ExampleObject1Data data1;
  92     ExampleObject1Data data2;
  93     int32_t step;
  94
  95     // Main task loop
  96     while (1) {
  97         // Check the event queue for any object updates. In this case
  98         // we are only listening for the ExampleSettings object. However
  99         // the module could listen to multiple objects.
 100         // Since this object only executes on object updates, the task
 101         // will block until an object event is pushed in the queue.
 102         while (xQueueReceive(queue, &ev, portMAX_DELAY) != pdTRUE) {
 103             ;
 104         }
 105
 106         // Make sure that the object update is for ExampleObject1
 107         // This is redundant in this example since we have only
 108         // registered a single object in the queue, however
 109         // in most practical cases there will be more than one
 110         // object connected in the queue.
 111         if (ev.obj == ExampleObject1Handle()) {
 112             // Update settings with latest value
 113             ExampleSettingsGet(&settings);
 114
 115             // Get the input object
 116             ExampleObject1Get(&data1);
 117
 118             // Determine how to update the output object
 119             if (settings.StepDirection == EXAMPLESETTINGS_STEPDIRECTION_UP) {
 120                 step = settings.StepSize;
 121             } else {
 122                 step = -settings.StepSize;
 123             }
 124
 125             // Update data
 126             data2.Field1    = data1.Field1 + step;
 127             data2.Field2    = data1.Field2 + step;
 128             data2.Field3    = data1.Field3 + step;
 129             data2.Field4[0] = data1.Field4[0] + step;
 130             data2.Field4[1] = data1.Field4[1] + step;
 131
 132             // Update the ExampleObject2, after this function is called
 133             // notifications to any other modules listening to that object
 134             // will be sent and the GCS object will be updated through the
 135             // telemetry link. All operations will take place asynchronously
 136             // and the following call will return immediately.
 137             ExampleObject2Set(&data2);
 138         }
 139     }
 140 }