2 FreeRTOS V7.4.2 - Copyright (C) 2013 Real Time Engineers Ltd.
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4 FEATURES AND PORTS ARE ADDED TO FREERTOS ALL THE TIME. PLEASE VISIT
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5 http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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7 ***************************************************************************
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9 * FreeRTOS tutorial books are available in pdf and paperback. *
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10 * Complete, revised, and edited pdf reference manuals are also *
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13 * Purchasing FreeRTOS documentation will not only help you, by *
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14 * ensuring you get running as quickly as possible and with an *
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15 * in-depth knowledge of how to use FreeRTOS, it will also help *
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16 * the FreeRTOS project to continue with its mission of providing *
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17 * professional grade, cross platform, de facto standard solutions *
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18 * for microcontrollers - completely free of charge! *
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20 * >>> See http://www.FreeRTOS.org/Documentation for details. <<< *
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22 * Thank you for using FreeRTOS, and thank you for your support! *
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24 ***************************************************************************
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27 This file is part of the FreeRTOS distribution.
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29 FreeRTOS is free software; you can redistribute it and/or modify it under
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30 the terms of the GNU General Public License (version 2) as published by the
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31 Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
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33 >>>>>>NOTE<<<<<< The modification to the GPL is included to allow you to
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34 distribute a combined work that includes FreeRTOS without being obliged to
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35 provide the source code for proprietary components outside of the FreeRTOS
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38 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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39 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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40 FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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41 details. You should have received a copy of the GNU General Public License
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42 and the FreeRTOS license exception along with FreeRTOS; if not it can be
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43 viewed here: http://www.freertos.org/a00114.html and also obtained by
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44 writing to Real Time Engineers Ltd., contact details for whom are available
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45 on the FreeRTOS WEB site.
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49 ***************************************************************************
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51 * Having a problem? Start by reading the FAQ "My application does *
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52 * not run, what could be wrong?" *
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54 * http://www.FreeRTOS.org/FAQHelp.html *
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56 ***************************************************************************
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59 http://www.FreeRTOS.org - Documentation, books, training, latest versions,
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60 license and Real Time Engineers Ltd. contact details.
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62 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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63 including FreeRTOS+Trace - an indispensable productivity tool, and our new
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64 fully thread aware and reentrant UDP/IP stack.
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66 http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
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67 Integrity Systems, who sell the code with commercial support,
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68 indemnification and middleware, under the OpenRTOS brand.
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70 http://www.SafeRTOS.com - High Integrity Systems also provide a safety
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71 engineered and independently SIL3 certified version for use in safety and
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72 mission critical applications that require provable dependability.
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76 * Create a single persistent task which periodically dynamically creates another
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77 * two tasks. The original task is called the creator task, the two tasks it
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78 * creates are called suicidal tasks.
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80 * One of the created suicidal tasks kill one other suicidal task before killing
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81 * itself - leaving just the original task remaining.
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83 * The creator task must be spawned after all of the other demo application tasks
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84 * as it keeps a check on the number of tasks under the scheduler control. The
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85 * number of tasks it expects to see running should never be greater than the
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86 * number of tasks that were in existence when the creator task was spawned, plus
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87 * one set of four suicidal tasks. If this number is exceeded an error is flagged.
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89 * \page DeathC death.c
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90 * \ingroup DemoFiles
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96 + CreationCount sizes changed from unsigned portBASE_TYPE to
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97 unsigned short to minimize the risk of overflowing.
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99 + Reset of usLastCreationCount added
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101 Changes from V3.1.0
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102 + Changed the dummy calculation to use variables of type long, rather than
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103 float. This allows the file to be used with ports that do not support
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108 #include <stdlib.h>
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110 /* Scheduler include files. */
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111 #include "FreeRTOS.h"
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114 /* Demo program include files. */
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117 #define deathSTACK_SIZE ( configMINIMAL_STACK_SIZE + 60 )
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119 /* The task originally created which is responsible for periodically dynamically
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120 creating another four tasks. */
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121 static portTASK_FUNCTION_PROTO( vCreateTasks, pvParameters );
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123 /* The task function of the dynamically created tasks. */
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124 static portTASK_FUNCTION_PROTO( vSuicidalTask, pvParameters );
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126 /* A variable which is incremented every time the dynamic tasks are created. This
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127 is used to check that the task is still running. */
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128 static volatile unsigned short usCreationCount = 0;
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130 /* Used to store the number of tasks that were originally running so the creator
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131 task can tell if any of the suicidal tasks have failed to die.
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133 static volatile unsigned portBASE_TYPE uxTasksRunningAtStart = 0;
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135 /* Tasks are deleted by the idle task. Under heavy load the idle task might
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136 not get much processing time, so it would be legitimate for several tasks to
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137 remain undeleted for a short period. */
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138 static const unsigned portBASE_TYPE uxMaxNumberOfExtraTasksRunning = 3;
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140 /* Used to store a handle to the task that should be killed by a suicidal task,
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141 before it kills itself. */
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142 xTaskHandle xCreatedTask;
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144 /*-----------------------------------------------------------*/
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146 void vCreateSuicidalTasks( unsigned portBASE_TYPE uxPriority )
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148 unsigned portBASE_TYPE *puxPriority;
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150 /* Create the Creator tasks - passing in as a parameter the priority at which
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151 the suicidal tasks should be created. */
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152 puxPriority = ( unsigned portBASE_TYPE * ) pvPortMalloc( sizeof( unsigned portBASE_TYPE ) );
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153 *puxPriority = uxPriority;
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155 xTaskCreate( vCreateTasks, ( signed char * ) "CREATOR", deathSTACK_SIZE, ( void * ) puxPriority, uxPriority, NULL );
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157 /* Record the number of tasks that are running now so we know if any of the
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158 suicidal tasks have failed to be killed. */
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159 uxTasksRunningAtStart = ( unsigned portBASE_TYPE ) uxTaskGetNumberOfTasks();
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161 /* FreeRTOS.org versions before V3.0 started the idle-task as the very
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162 first task. The idle task was then already included in uxTasksRunningAtStart.
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163 From FreeRTOS V3.0 on, the idle task is started when the scheduler is
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164 started. Therefore the idle task is not yet accounted for. We correct
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165 this by increasing uxTasksRunningAtStart by 1. */
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166 uxTasksRunningAtStart++;
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168 /* From FreeRTOS version 7.0.0 can optionally create a timer service task.
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169 If this is done, then uxTasksRunningAtStart needs incrementing again as that
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170 too is created when the scheduler is started. */
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171 #if configUSE_TIMERS == 1
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172 uxTasksRunningAtStart++;
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175 /*-----------------------------------------------------------*/
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177 static portTASK_FUNCTION( vSuicidalTask, pvParameters )
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179 volatile long l1, l2;
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180 xTaskHandle xTaskToKill;
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181 const portTickType xDelay = ( portTickType ) 200 / portTICK_RATE_MS;
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183 if( pvParameters != NULL )
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185 /* This task is periodically created four times. Two created tasks are
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186 passed a handle to the other task so it can kill it before killing itself.
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187 The other task is passed in null. */
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188 xTaskToKill = *( xTaskHandle* )pvParameters;
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192 xTaskToKill = NULL;
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197 /* Do something random just to use some stack and registers. */
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201 vTaskDelay( xDelay );
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203 if( xTaskToKill != NULL )
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205 /* Make sure the other task has a go before we delete it. */
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206 vTaskDelay( ( portTickType ) 0 );
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208 /* Kill the other task that was created by vCreateTasks(). */
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209 vTaskDelete( xTaskToKill );
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211 /* Kill ourselves. */
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212 vTaskDelete( NULL );
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215 }/*lint !e818 !e550 Function prototype must be as per standard for task functions. */
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216 /*-----------------------------------------------------------*/
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218 static portTASK_FUNCTION( vCreateTasks, pvParameters )
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220 const portTickType xDelay = ( portTickType ) 1000 / portTICK_RATE_MS;
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221 unsigned portBASE_TYPE uxPriority;
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223 uxPriority = *( unsigned portBASE_TYPE * ) pvParameters;
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224 vPortFree( pvParameters );
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228 /* Just loop round, delaying then creating the four suicidal tasks. */
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229 vTaskDelay( xDelay );
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231 xCreatedTask = NULL;
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233 xTaskCreate( vSuicidalTask, ( signed char * ) "SUICID1", configMINIMAL_STACK_SIZE, NULL, uxPriority, &xCreatedTask );
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234 xTaskCreate( vSuicidalTask, ( signed char * ) "SUICID2", configMINIMAL_STACK_SIZE, &xCreatedTask, uxPriority, NULL );
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239 /*-----------------------------------------------------------*/
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241 /* This is called to check that the creator task is still running and that there
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242 are not any more than four extra tasks. */
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243 portBASE_TYPE xIsCreateTaskStillRunning( void )
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245 static unsigned short usLastCreationCount = 0xfff;
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246 portBASE_TYPE xReturn = pdTRUE;
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247 static unsigned portBASE_TYPE uxTasksRunningNow;
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249 if( usLastCreationCount == usCreationCount )
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255 usLastCreationCount = usCreationCount;
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258 uxTasksRunningNow = ( unsigned portBASE_TYPE ) uxTaskGetNumberOfTasks();
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260 if( uxTasksRunningNow < uxTasksRunningAtStart )
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264 else if( ( uxTasksRunningNow - uxTasksRunningAtStart ) > uxMaxNumberOfExtraTasksRunning )
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270 /* Everything is okay. */
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