2 FreeRTOS.org V5.4.0 - Copyright (C) 2003-2009 Richard Barry.
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4 This file is part of the FreeRTOS.org distribution.
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6 FreeRTOS.org is free software; you can redistribute it and/or modify it
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7 under the terms of the GNU General Public License (version 2) as published
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8 by the Free Software Foundation and modified by the FreeRTOS exception.
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9 **NOTE** The exception to the GPL is included to allow you to distribute a
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10 combined work that includes FreeRTOS.org without being obliged to provide
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11 the source code for any proprietary components. Alternative commercial
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12 license and support terms are also available upon request. See the
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13 licensing section of http://www.FreeRTOS.org for full details.
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15 FreeRTOS.org is distributed in the hope that it will be useful, but WITHOUT
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16 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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17 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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20 You should have received a copy of the GNU General Public License along
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21 with FreeRTOS.org; if not, write to the Free Software Foundation, Inc., 59
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22 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
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25 ***************************************************************************
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27 * Get the FreeRTOS eBook! See http://www.FreeRTOS.org/Documentation *
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29 * This is a concise, step by step, 'hands on' guide that describes both *
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30 * general multitasking concepts and FreeRTOS specifics. It presents and *
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31 * explains numerous examples that are written using the FreeRTOS API. *
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32 * Full source code for all the examples is provided in an accompanying *
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35 ***************************************************************************
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39 Please ensure to read the configuration and relevant port sections of the
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40 online documentation.
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42 http://www.FreeRTOS.org - Documentation, latest information, license and
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45 http://www.SafeRTOS.com - A version that is certified for use in safety
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48 http://www.OpenRTOS.com - Commercial support, development, porting,
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49 licensing and training services.
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53 #ifndef INC_FREERTOS_H
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54 #error "#include FreeRTOS.h" must appear in source files before "#include task.h"
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62 #include "portable.h"
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69 /*-----------------------------------------------------------
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70 * MACROS AND DEFINITIONS
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71 *----------------------------------------------------------*/
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73 #define tskKERNEL_VERSION_NUMBER "V5.4.0"
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78 * Type by which tasks are referenced. For example, a call to xTaskCreate
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79 * returns (via a pointer parameter) an xTaskHandle variable that can then
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80 * be used as a parameter to vTaskDelete to delete the task.
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82 * \page xTaskHandle xTaskHandle
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85 typedef void * xTaskHandle;
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88 * Used internally only.
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90 typedef struct xTIME_OUT
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92 portBASE_TYPE xOverflowCount;
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93 portTickType xTimeOnEntering;
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97 * Defines the priority used by the idle task. This must not be modified.
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99 * \ingroup TaskUtils
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101 #define tskIDLE_PRIORITY ( ( unsigned portBASE_TYPE ) 0 )
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106 * Macro for forcing a context switch.
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108 * \page taskYIELD taskYIELD
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109 * \ingroup SchedulerControl
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111 #define taskYIELD() portYIELD()
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116 * Macro to mark the start of a critical code region. Preemptive context
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117 * switches cannot occur when in a critical region.
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119 * NOTE: This may alter the stack (depending on the portable implementation)
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120 * so must be used with care!
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122 * \page taskENTER_CRITICAL taskENTER_CRITICAL
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123 * \ingroup SchedulerControl
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125 #define taskENTER_CRITICAL() portENTER_CRITICAL()
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130 * Macro to mark the end of a critical code region. Preemptive context
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131 * switches cannot occur when in a critical region.
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133 * NOTE: This may alter the stack (depending on the portable implementation)
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134 * so must be used with care!
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136 * \page taskEXIT_CRITICAL taskEXIT_CRITICAL
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137 * \ingroup SchedulerControl
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139 #define taskEXIT_CRITICAL() portEXIT_CRITICAL()
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144 * Macro to disable all maskable interrupts.
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146 * \page taskDISABLE_INTERRUPTS taskDISABLE_INTERRUPTS
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147 * \ingroup SchedulerControl
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149 #define taskDISABLE_INTERRUPTS() portDISABLE_INTERRUPTS()
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154 * Macro to enable microcontroller interrupts.
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156 * \page taskENABLE_INTERRUPTS taskENABLE_INTERRUPTS
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157 * \ingroup SchedulerControl
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159 #define taskENABLE_INTERRUPTS() portENABLE_INTERRUPTS()
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161 /* Definitions returned by xTaskGetSchedulerState(). */
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162 #define taskSCHEDULER_NOT_STARTED 0
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163 #define taskSCHEDULER_RUNNING 1
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164 #define taskSCHEDULER_SUSPENDED 2
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166 /*-----------------------------------------------------------
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167 * TASK CREATION API
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168 *----------------------------------------------------------*/
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173 portBASE_TYPE xTaskCreate(
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174 pdTASK_CODE pvTaskCode,
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175 const portCHAR * const pcName,
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176 unsigned portSHORT usStackDepth,
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177 void *pvParameters,
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178 unsigned portBASE_TYPE uxPriority,
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179 xTaskHandle *pvCreatedTask
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182 * Create a new task and add it to the list of tasks that are ready to run.
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184 * @param pvTaskCode Pointer to the task entry function. Tasks
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185 * must be implemented to never return (i.e. continuous loop).
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187 * @param pcName A descriptive name for the task. This is mainly used to
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188 * facilitate debugging. Max length defined by tskMAX_TASK_NAME_LEN - default
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191 * @param usStackDepth The size of the task stack specified as the number of
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192 * variables the stack can hold - not the number of bytes. For example, if
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193 * the stack is 16 bits wide and usStackDepth is defined as 100, 200 bytes
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194 * will be allocated for stack storage.
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196 * @param pvParameters Pointer that will be used as the parameter for the task
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199 * @param uxPriority The priority at which the task should run.
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201 * @param pvCreatedTask Used to pass back a handle by which the created task
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202 * can be referenced.
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204 * @return pdPASS if the task was successfully created and added to a ready
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205 * list, otherwise an error code defined in the file errors. h
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209 // Task to be created.
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210 void vTaskCode( void * pvParameters )
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214 // Task code goes here.
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218 // Function that creates a task.
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219 void vOtherFunction( void )
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221 static unsigned char ucParameterToPass;
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222 xTaskHandle xHandle;
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224 // Create the task, storing the handle. Note that the passed parameter ucParameterToPass
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225 // must exist for the lifetime of the task, so in this case is declared static. If it was just an
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226 // an automatic stack variable it might no longer exist, or at least have been corrupted, by the time
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227 // the new time attempts to access it.
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228 xTaskCreate( vTaskCode, "NAME", STACK_SIZE, &ucParameterToPass, tskIDLE_PRIORITY, &xHandle );
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230 // Use the handle to delete the task.
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231 vTaskDelete( xHandle );
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234 * \defgroup xTaskCreate xTaskCreate
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237 signed portBASE_TYPE xTaskCreate( pdTASK_CODE pvTaskCode, const signed portCHAR * const pcName, unsigned portSHORT usStackDepth, void *pvParameters, unsigned portBASE_TYPE uxPriority, xTaskHandle *pvCreatedTask );
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241 * <pre>void vTaskDelete( xTaskHandle pxTask );</pre>
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243 * INCLUDE_vTaskDelete must be defined as 1 for this function to be available.
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244 * See the configuration section for more information.
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246 * Remove a task from the RTOS real time kernels management. The task being
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247 * deleted will be removed from all ready, blocked, suspended and event lists.
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249 * NOTE: The idle task is responsible for freeing the kernel allocated
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250 * memory from tasks that have been deleted. It is therefore important that
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251 * the idle task is not starved of microcontroller processing time if your
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252 * application makes any calls to vTaskDelete (). Memory allocated by the
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253 * task code is not automatically freed, and should be freed before the task
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256 * See the demo application file death.c for sample code that utilises
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259 * @param pxTask The handle of the task to be deleted. Passing NULL will
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260 * cause the calling task to be deleted.
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264 void vOtherFunction( void )
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266 xTaskHandle xHandle;
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268 // Create the task, storing the handle.
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269 xTaskCreate( vTaskCode, "NAME", STACK_SIZE, NULL, tskIDLE_PRIORITY, &xHandle );
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271 // Use the handle to delete the task.
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272 vTaskDelete( xHandle );
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275 * \defgroup vTaskDelete vTaskDelete
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278 void vTaskDelete( xTaskHandle pxTask );
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281 /*-----------------------------------------------------------
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283 *----------------------------------------------------------*/
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287 * <pre>void vTaskDelay( portTickType xTicksToDelay );</pre>
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289 * Delay a task for a given number of ticks. The actual time that the
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290 * task remains blocked depends on the tick rate. The constant
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291 * portTICK_RATE_MS can be used to calculate real time from the tick
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292 * rate - with the resolution of one tick period.
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294 * INCLUDE_vTaskDelay must be defined as 1 for this function to be available.
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295 * See the configuration section for more information.
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298 * vTaskDelay() specifies a time at which the task wishes to unblock relative to
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299 * the time at which vTaskDelay() is called. For example, specifying a block
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300 * period of 100 ticks will cause the task to unblock 100 ticks after
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301 * vTaskDelay() is called. vTaskDelay() does not therefore provide a good method
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302 * of controlling the frequency of a cyclical task as the path taken through the
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303 * code, as well as other task and interrupt activity, will effect the frequency
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304 * at which vTaskDelay() gets called and therefore the time at which the task
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305 * next executes. See vTaskDelayUntil() for an alternative API function designed
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306 * to facilitate fixed frequency execution. It does this by specifying an
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307 * absolute time (rather than a relative time) at which the calling task should
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310 * @param xTicksToDelay The amount of time, in tick periods, that
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311 * the calling task should block.
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315 void vTaskFunction( void * pvParameters )
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317 void vTaskFunction( void * pvParameters )
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319 // Block for 500ms.
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320 const portTickType xDelay = 500 / portTICK_RATE_MS;
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324 // Simply toggle the LED every 500ms, blocking between each toggle.
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326 vTaskDelay( xDelay );
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330 * \defgroup vTaskDelay vTaskDelay
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331 * \ingroup TaskCtrl
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333 void vTaskDelay( portTickType xTicksToDelay );
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337 * <pre>void vTaskDelayUntil( portTickType *pxPreviousWakeTime, portTickType xTimeIncrement );</pre>
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339 * INCLUDE_vTaskDelayUntil must be defined as 1 for this function to be available.
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340 * See the configuration section for more information.
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342 * Delay a task until a specified time. This function can be used by cyclical
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343 * tasks to ensure a constant execution frequency.
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345 * This function differs from vTaskDelay () in one important aspect: vTaskDelay () will
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346 * cause a task to block for the specified number of ticks from the time vTaskDelay () is
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347 * called. It is therefore difficult to use vTaskDelay () by itself to generate a fixed
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348 * execution frequency as the time between a task starting to execute and that task
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349 * calling vTaskDelay () may not be fixed [the task may take a different path though the
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350 * code between calls, or may get interrupted or preempted a different number of times
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351 * each time it executes].
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353 * Whereas vTaskDelay () specifies a wake time relative to the time at which the function
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354 * is called, vTaskDelayUntil () specifies the absolute (exact) time at which it wishes to
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357 * The constant portTICK_RATE_MS can be used to calculate real time from the tick
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358 * rate - with the resolution of one tick period.
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360 * @param pxPreviousWakeTime Pointer to a variable that holds the time at which the
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361 * task was last unblocked. The variable must be initialised with the current time
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362 * prior to its first use (see the example below). Following this the variable is
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363 * automatically updated within vTaskDelayUntil ().
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365 * @param xTimeIncrement The cycle time period. The task will be unblocked at
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366 * time *pxPreviousWakeTime + xTimeIncrement. Calling vTaskDelayUntil with the
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367 * same xTimeIncrement parameter value will cause the task to execute with
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368 * a fixed interface period.
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372 // Perform an action every 10 ticks.
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373 void vTaskFunction( void * pvParameters )
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375 portTickType xLastWakeTime;
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376 const portTickType xFrequency = 10;
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378 // Initialise the xLastWakeTime variable with the current time.
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379 xLastWakeTime = xTaskGetTickCount ();
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382 // Wait for the next cycle.
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383 vTaskDelayUntil( &xLastWakeTime, xFrequency );
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385 // Perform action here.
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389 * \defgroup vTaskDelayUntil vTaskDelayUntil
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390 * \ingroup TaskCtrl
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392 void vTaskDelayUntil( portTickType * const pxPreviousWakeTime, portTickType xTimeIncrement );
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396 * <pre>unsigned portBASE_TYPE uxTaskPriorityGet( xTaskHandle pxTask );</pre>
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398 * INCLUDE_xTaskPriorityGet must be defined as 1 for this function to be available.
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399 * See the configuration section for more information.
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401 * Obtain the priority of any task.
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403 * @param pxTask Handle of the task to be queried. Passing a NULL
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404 * handle results in the priority of the calling task being returned.
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406 * @return The priority of pxTask.
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410 void vAFunction( void )
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412 xTaskHandle xHandle;
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414 // Create a task, storing the handle.
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415 xTaskCreate( vTaskCode, "NAME", STACK_SIZE, NULL, tskIDLE_PRIORITY, &xHandle );
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419 // Use the handle to obtain the priority of the created task.
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420 // It was created with tskIDLE_PRIORITY, but may have changed
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422 if( uxTaskPriorityGet( xHandle ) != tskIDLE_PRIORITY )
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424 // The task has changed it's priority.
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429 // Is our priority higher than the created task?
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430 if( uxTaskPriorityGet( xHandle ) < uxTaskPriorityGet( NULL ) )
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432 // Our priority (obtained using NULL handle) is higher.
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436 * \defgroup uxTaskPriorityGet uxTaskPriorityGet
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437 * \ingroup TaskCtrl
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439 unsigned portBASE_TYPE uxTaskPriorityGet( xTaskHandle pxTask );
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443 * <pre>void vTaskPrioritySet( xTaskHandle pxTask, unsigned portBASE_TYPE uxNewPriority );</pre>
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445 * INCLUDE_vTaskPrioritySet must be defined as 1 for this function to be available.
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446 * See the configuration section for more information.
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448 * Set the priority of any task.
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450 * A context switch will occur before the function returns if the priority
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451 * being set is higher than the currently executing task.
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453 * @param pxTask Handle to the task for which the priority is being set.
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454 * Passing a NULL handle results in the priority of the calling task being set.
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456 * @param uxNewPriority The priority to which the task will be set.
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460 void vAFunction( void )
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462 xTaskHandle xHandle;
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464 // Create a task, storing the handle.
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465 xTaskCreate( vTaskCode, "NAME", STACK_SIZE, NULL, tskIDLE_PRIORITY, &xHandle );
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469 // Use the handle to raise the priority of the created task.
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470 vTaskPrioritySet( xHandle, tskIDLE_PRIORITY + 1 );
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474 // Use a NULL handle to raise our priority to the same value.
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475 vTaskPrioritySet( NULL, tskIDLE_PRIORITY + 1 );
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478 * \defgroup vTaskPrioritySet vTaskPrioritySet
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479 * \ingroup TaskCtrl
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481 void vTaskPrioritySet( xTaskHandle pxTask, unsigned portBASE_TYPE uxNewPriority );
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485 * <pre>void vTaskSuspend( xTaskHandle pxTaskToSuspend );</pre>
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487 * INCLUDE_vTaskSuspend must be defined as 1 for this function to be available.
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488 * See the configuration section for more information.
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490 * Suspend any task. When suspended a task will never get any microcontroller
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491 * processing time, no matter what its priority.
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493 * Calls to vTaskSuspend are not accumulative -
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494 * i.e. calling vTaskSuspend () twice on the same task still only requires one
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495 * call to vTaskResume () to ready the suspended task.
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497 * @param pxTaskToSuspend Handle to the task being suspended. Passing a NULL
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498 * handle will cause the calling task to be suspended.
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502 void vAFunction( void )
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504 xTaskHandle xHandle;
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506 // Create a task, storing the handle.
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507 xTaskCreate( vTaskCode, "NAME", STACK_SIZE, NULL, tskIDLE_PRIORITY, &xHandle );
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511 // Use the handle to suspend the created task.
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512 vTaskSuspend( xHandle );
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516 // The created task will not run during this period, unless
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517 // another task calls vTaskResume( xHandle ).
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522 // Suspend ourselves.
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523 vTaskSuspend( NULL );
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525 // We cannot get here unless another task calls vTaskResume
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526 // with our handle as the parameter.
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529 * \defgroup vTaskSuspend vTaskSuspend
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530 * \ingroup TaskCtrl
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532 void vTaskSuspend( xTaskHandle pxTaskToSuspend );
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536 * <pre>void vTaskResume( xTaskHandle pxTaskToResume );</pre>
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538 * INCLUDE_vTaskSuspend must be defined as 1 for this function to be available.
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539 * See the configuration section for more information.
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541 * Resumes a suspended task.
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543 * A task that has been suspended by one of more calls to vTaskSuspend ()
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544 * will be made available for running again by a single call to
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547 * @param pxTaskToResume Handle to the task being readied.
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551 void vAFunction( void )
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553 xTaskHandle xHandle;
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555 // Create a task, storing the handle.
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556 xTaskCreate( vTaskCode, "NAME", STACK_SIZE, NULL, tskIDLE_PRIORITY, &xHandle );
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560 // Use the handle to suspend the created task.
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561 vTaskSuspend( xHandle );
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565 // The created task will not run during this period, unless
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566 // another task calls vTaskResume( xHandle ).
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571 // Resume the suspended task ourselves.
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572 vTaskResume( xHandle );
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574 // The created task will once again get microcontroller processing
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575 // time in accordance with it priority within the system.
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578 * \defgroup vTaskResume vTaskResume
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579 * \ingroup TaskCtrl
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581 void vTaskResume( xTaskHandle pxTaskToResume );
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585 * <pre>void xTaskResumeFromISR( xTaskHandle pxTaskToResume );</pre>
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587 * INCLUDE_xTaskResumeFromISR must be defined as 1 for this function to be
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588 * available. See the configuration section for more information.
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590 * An implementation of vTaskResume() that can be called from within an ISR.
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592 * A task that has been suspended by one of more calls to vTaskSuspend ()
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593 * will be made available for running again by a single call to
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594 * xTaskResumeFromISR ().
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596 * @param pxTaskToResume Handle to the task being readied.
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598 * \defgroup vTaskResumeFromISR vTaskResumeFromISR
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599 * \ingroup TaskCtrl
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601 portBASE_TYPE xTaskResumeFromISR( xTaskHandle pxTaskToResume );
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603 /*-----------------------------------------------------------
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604 * SCHEDULER CONTROL
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605 *----------------------------------------------------------*/
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609 * <pre>void vTaskStartScheduler( void );</pre>
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611 * Starts the real time kernel tick processing. After calling the kernel
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612 * has control over which tasks are executed and when. This function
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613 * does not return until an executing task calls vTaskEndScheduler ().
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615 * At least one task should be created via a call to xTaskCreate ()
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616 * before calling vTaskStartScheduler (). The idle task is created
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617 * automatically when the first application task is created.
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619 * See the demo application file main.c for an example of creating
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620 * tasks and starting the kernel.
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624 void vAFunction( void )
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626 // Create at least one task before starting the kernel.
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627 xTaskCreate( vTaskCode, "NAME", STACK_SIZE, NULL, tskIDLE_PRIORITY, NULL );
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629 // Start the real time kernel with preemption.
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630 vTaskStartScheduler ();
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632 // Will not get here unless a task calls vTaskEndScheduler ()
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636 * \defgroup vTaskStartScheduler vTaskStartScheduler
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637 * \ingroup SchedulerControl
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639 void vTaskStartScheduler( void );
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643 * <pre>void vTaskEndScheduler( void );</pre>
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645 * Stops the real time kernel tick. All created tasks will be automatically
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646 * deleted and multitasking (either preemptive or cooperative) will
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647 * stop. Execution then resumes from the point where vTaskStartScheduler ()
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648 * was called, as if vTaskStartScheduler () had just returned.
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650 * See the demo application file main. c in the demo/PC directory for an
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651 * example that uses vTaskEndScheduler ().
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653 * vTaskEndScheduler () requires an exit function to be defined within the
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654 * portable layer (see vPortEndScheduler () in port. c for the PC port). This
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655 * performs hardware specific operations such as stopping the kernel tick.
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657 * vTaskEndScheduler () will cause all of the resources allocated by the
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658 * kernel to be freed - but will not free resources allocated by application
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663 void vTaskCode( void * pvParameters )
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667 // Task code goes here.
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669 // At some point we want to end the real time kernel processing
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671 vTaskEndScheduler ();
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675 void vAFunction( void )
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677 // Create at least one task before starting the kernel.
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678 xTaskCreate( vTaskCode, "NAME", STACK_SIZE, NULL, tskIDLE_PRIORITY, NULL );
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680 // Start the real time kernel with preemption.
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681 vTaskStartScheduler ();
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683 // Will only get here when the vTaskCode () task has called
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684 // vTaskEndScheduler (). When we get here we are back to single task
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689 * \defgroup vTaskEndScheduler vTaskEndScheduler
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690 * \ingroup SchedulerControl
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692 void vTaskEndScheduler( void );
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696 * <pre>void vTaskSuspendAll( void );</pre>
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698 * Suspends all real time kernel activity while keeping interrupts (including the
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699 * kernel tick) enabled.
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701 * After calling vTaskSuspendAll () the calling task will continue to execute
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702 * without risk of being swapped out until a call to xTaskResumeAll () has been
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705 * API functions that have the potential to cause a context switch (for example,
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706 * vTaskDelayUntil(), xQueueSend(), etc.) must not be called while the scheduler
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711 void vTask1( void * pvParameters )
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715 // Task code goes here.
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719 // At some point the task wants to perform a long operation during
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720 // which it does not want to get swapped out. It cannot use
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721 // taskENTER_CRITICAL ()/taskEXIT_CRITICAL () as the length of the
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722 // operation may cause interrupts to be missed - including the
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725 // Prevent the real time kernel swapping out the task.
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726 vTaskSuspendAll ();
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728 // Perform the operation here. There is no need to use critical
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729 // sections as we have all the microcontroller processing time.
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730 // During this time interrupts will still operate and the kernel
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731 // tick count will be maintained.
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735 // The operation is complete. Restart the kernel.
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740 * \defgroup vTaskSuspendAll vTaskSuspendAll
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741 * \ingroup SchedulerControl
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743 void vTaskSuspendAll( void );
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747 * <pre>portCHAR xTaskResumeAll( void );</pre>
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749 * Resumes real time kernel activity following a call to vTaskSuspendAll ().
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750 * After a call to vTaskSuspendAll () the kernel will take control of which
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751 * task is executing at any time.
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753 * @return If resuming the scheduler caused a context switch then pdTRUE is
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754 * returned, otherwise pdFALSE is returned.
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758 void vTask1( void * pvParameters )
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762 // Task code goes here.
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766 // At some point the task wants to perform a long operation during
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767 // which it does not want to get swapped out. It cannot use
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768 // taskENTER_CRITICAL ()/taskEXIT_CRITICAL () as the length of the
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769 // operation may cause interrupts to be missed - including the
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772 // Prevent the real time kernel swapping out the task.
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773 vTaskSuspendAll ();
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775 // Perform the operation here. There is no need to use critical
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776 // sections as we have all the microcontroller processing time.
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777 // During this time interrupts will still operate and the real
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778 // time kernel tick count will be maintained.
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782 // The operation is complete. Restart the kernel. We want to force
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783 // a context switch - but there is no point if resuming the scheduler
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784 // caused a context switch already.
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785 if( !xTaskResumeAll () )
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792 * \defgroup xTaskResumeAll xTaskResumeAll
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793 * \ingroup SchedulerControl
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795 signed portBASE_TYPE xTaskResumeAll( void );
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799 * <pre>signed portBASE_TYPE xTaskIsTaskSuspended( xTaskHandle xTask );</pre>
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801 * Utility task that simply returns pdTRUE if the task referenced by xTask is
\r
802 * currently in the Suspended state, or pdFALSE if the task referenced by xTask
\r
803 * is in any other state.
\r
806 signed portBASE_TYPE xTaskIsTaskSuspended( xTaskHandle xTask );
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808 /*-----------------------------------------------------------
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810 *----------------------------------------------------------*/
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814 * <PRE>volatile portTickType xTaskGetTickCount( void );</PRE>
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816 * @return The count of ticks since vTaskStartScheduler was called.
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818 * \page xTaskGetTickCount xTaskGetTickCount
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819 * \ingroup TaskUtils
\r
821 portTickType xTaskGetTickCount( void );
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825 * <PRE>unsigned portSHORT uxTaskGetNumberOfTasks( void );</PRE>
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827 * @return The number of tasks that the real time kernel is currently managing.
\r
828 * This includes all ready, blocked and suspended tasks. A task that
\r
829 * has been deleted but not yet freed by the idle task will also be
\r
830 * included in the count.
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832 * \page uxTaskGetNumberOfTasks uxTaskGetNumberOfTasks
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833 * \ingroup TaskUtils
\r
835 unsigned portBASE_TYPE uxTaskGetNumberOfTasks( void );
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839 * <PRE>void vTaskList( portCHAR *pcWriteBuffer );</PRE>
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841 * configUSE_TRACE_FACILITY must be defined as 1 for this function to be
\r
842 * available. See the configuration section for more information.
\r
844 * NOTE: This function will disable interrupts for its duration. It is
\r
845 * not intended for normal application runtime use but as a debug aid.
\r
847 * Lists all the current tasks, along with their current state and stack
\r
848 * usage high water mark.
\r
850 * Tasks are reported as blocked ('B'), ready ('R'), deleted ('D') or
\r
853 * @param pcWriteBuffer A buffer into which the above mentioned details
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854 * will be written, in ascii form. This buffer is assumed to be large
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855 * enough to contain the generated report. Approximately 40 bytes per
\r
856 * task should be sufficient.
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858 * \page vTaskList vTaskList
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859 * \ingroup TaskUtils
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861 void vTaskList( signed portCHAR *pcWriteBuffer );
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865 * <PRE>void vTaskGetRunTimeStats( portCHAR *pcWriteBuffer );</PRE>
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867 * configGENERATE_RUN_TIME_STATS must be defined as 1 for this function
\r
868 * to be available. The application must also then provide definitions
\r
869 * for portCONFIGURE_TIMER_FOR_RUN_TIME_STATS() and
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870 * portGET_RUN_TIME_COUNTER_VALUE to configure a peripheral timer/counter
\r
871 * and return the timers current count value respectively. The counter
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872 * should be at least 10 times the frequency of the tick count.
\r
874 * NOTE: This function will disable interrupts for its duration. It is
\r
875 * not intended for normal application runtime use but as a debug aid.
\r
877 * Setting configGENERATE_RUN_TIME_STATS to 1 will result in a total
\r
878 * accumulated execution time being stored for each task. The resolution
\r
879 * of the accumulated time value depends on the frequency of the timer
\r
880 * configured by the portCONFIGURE_TIMER_FOR_RUN_TIME_STATS() macro.
\r
881 * Calling vTaskGetRunTimeStats() writes the total execution time of each
\r
882 * task into a buffer, both as an absolute count value and as a percentage
\r
883 * of the total system execution time.
\r
885 * @param pcWriteBuffer A buffer into which the execution times will be
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886 * written, in ascii form. This buffer is assumed to be large enough to
\r
887 * contain the generated report. Approximately 40 bytes per task should
\r
890 * \page vTaskGetRunTimeStats vTaskGetRunTimeStats
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891 * \ingroup TaskUtils
\r
893 void vTaskGetRunTimeStats( signed portCHAR *pcWriteBuffer );
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897 * <PRE>void vTaskStartTrace( portCHAR * pcBuffer, unsigned portBASE_TYPE uxBufferSize );</PRE>
\r
899 * Starts a real time kernel activity trace. The trace logs the identity of
\r
900 * which task is running when.
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902 * The trace file is stored in binary format. A separate DOS utility called
\r
903 * convtrce.exe is used to convert this into a tab delimited text file which
\r
904 * can be viewed and plotted in a spread sheet.
\r
906 * @param pcBuffer The buffer into which the trace will be written.
\r
908 * @param ulBufferSize The size of pcBuffer in bytes. The trace will continue
\r
909 * until either the buffer in full, or ulTaskEndTrace () is called.
\r
911 * \page vTaskStartTrace vTaskStartTrace
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912 * \ingroup TaskUtils
\r
914 void vTaskStartTrace( signed portCHAR * pcBuffer, unsigned portLONG ulBufferSize );
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918 * <PRE>unsigned portLONG ulTaskEndTrace( void );</PRE>
\r
920 * Stops a kernel activity trace. See vTaskStartTrace ().
\r
922 * @return The number of bytes that have been written into the trace buffer.
\r
924 * \page usTaskEndTrace usTaskEndTrace
\r
925 * \ingroup TaskUtils
\r
927 unsigned portLONG ulTaskEndTrace( void );
\r
931 * <PRE>unsigned portBASE_TYPE uxTaskGetStackHighWaterMark( xTaskHandle xTask );</PRE>
\r
933 * INCLUDE_uxTaskGetStackHighWaterMark must be set to 1 in FreeRTOSConfig.h for
\r
934 * this function to be available.
\r
936 * Returns the high water mark of the stack associated with xTask. That is,
\r
937 * the minimum free stack space there has been (in bytes) since the task
\r
938 * started. The smaller the returned number the closer the task has come
\r
939 * to overflowing its stack.
\r
941 * @param xTask Handle of the task associated with the stack to be checked.
\r
942 * Set xTask to NULL to check the stack of the calling task.
\r
944 * @return The smallest amount of free stack space there has been (in bytes)
\r
945 * since the task referenced by xTask was created.
\r
947 unsigned portBASE_TYPE uxTaskGetStackHighWaterMark( xTaskHandle xTask );
\r
951 * <pre>void vTaskSetApplicationTaskTag( xTaskHandle xTask, pdTASK_HOOK_CODE pxHookFunction );</pre>
\r
953 * Sets pxHookFunction to be the task hook function used by the task xTask.
\r
954 * Passing xTask as NULL has the effect of setting the calling tasks hook
\r
957 void vTaskSetApplicationTaskTag( xTaskHandle xTask, pdTASK_HOOK_CODE pxHookFunction );
\r
961 * <pre>void xTaskGetApplicationTaskTag( xTaskHandle xTask );</pre>
\r
963 * Returns the pxHookFunction value assigned to the task xTask.
\r
965 pdTASK_HOOK_CODE xTaskGetApplicationTaskTag( xTaskHandle xTask );
\r
969 * <pre>portBASE_TYPE xTaskCallApplicationTaskHook( xTaskHandle xTask, pdTASK_HOOK_CODE pxHookFunction );</pre>
\r
971 * Calls the hook function associated with xTask. Passing xTask as NULL has
\r
972 * the effect of calling the Running tasks (the calling task) hook function.
\r
974 * pvParameter is passed to the hook function for the task to interpret as it
\r
977 portBASE_TYPE xTaskCallApplicationTaskHook( xTaskHandle xTask, void *pvParameter );
\r
980 /*-----------------------------------------------------------
\r
981 * SCHEDULER INTERNALS AVAILABLE FOR PORTING PURPOSES
\r
982 *----------------------------------------------------------*/
\r
985 * THIS FUNCTION MUST NOT BE USED FROM APPLICATION CODE. IT IS ONLY
\r
986 * INTENDED FOR USE WHEN IMPLEMENTING A PORT OF THE SCHEDULER AND IS
\r
987 * AN INTERFACE WHICH IS FOR THE EXCLUSIVE USE OF THE SCHEDULER.
\r
989 * Called from the real time kernel tick (either preemptive or cooperative),
\r
990 * this increments the tick count and checks if any tasks that are blocked
\r
991 * for a finite period required removing from a blocked list and placing on
\r
994 void vTaskIncrementTick( void );
\r
997 * THIS FUNCTION MUST NOT BE USED FROM APPLICATION CODE. IT IS AN
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998 * INTERFACE WHICH IS FOR THE EXCLUSIVE USE OF THE SCHEDULER.
\r
1000 * THIS FUNCTION MUST BE CALLED WITH INTERRUPTS DISABLED.
\r
1002 * Removes the calling task from the ready list and places it both
\r
1003 * on the list of tasks waiting for a particular event, and the
\r
1004 * list of delayed tasks. The task will be removed from both lists
\r
1005 * and replaced on the ready list should either the event occur (and
\r
1006 * there be no higher priority tasks waiting on the same event) or
\r
1007 * the delay period expires.
\r
1009 * @param pxEventList The list containing tasks that are blocked waiting
\r
1010 * for the event to occur.
\r
1012 * @param xTicksToWait The maximum amount of time that the task should wait
\r
1013 * for the event to occur. This is specified in kernel ticks,the constant
\r
1014 * portTICK_RATE_MS can be used to convert kernel ticks into a real time
\r
1017 void vTaskPlaceOnEventList( const xList * const pxEventList, portTickType xTicksToWait );
\r
1020 * THIS FUNCTION MUST NOT BE USED FROM APPLICATION CODE. IT IS AN
\r
1021 * INTERFACE WHICH IS FOR THE EXCLUSIVE USE OF THE SCHEDULER.
\r
1023 * THIS FUNCTION MUST BE CALLED WITH INTERRUPTS DISABLED.
\r
1025 * Removes a task from both the specified event list and the list of blocked
\r
1026 * tasks, and places it on a ready queue.
\r
1028 * xTaskRemoveFromEventList () will be called if either an event occurs to
\r
1029 * unblock a task, or the block timeout period expires.
\r
1031 * @return pdTRUE if the task being removed has a higher priority than the task
\r
1032 * making the call, otherwise pdFALSE.
\r
1034 signed portBASE_TYPE xTaskRemoveFromEventList( const xList * const pxEventList );
\r
1037 * THIS FUNCTION MUST NOT BE USED FROM APPLICATION CODE. IT IS AN
\r
1038 * INTERFACE WHICH IS FOR THE EXCLUSIVE USE OF THE SCHEDULER.
\r
1040 * INCLUDE_vTaskCleanUpResources and INCLUDE_vTaskSuspend must be defined as 1
\r
1041 * for this function to be available.
\r
1042 * See the configuration section for more information.
\r
1044 * Empties the ready and delayed queues of task control blocks, freeing the
\r
1045 * memory allocated for the task control block and task stacks as it goes.
\r
1047 void vTaskCleanUpResources( void );
\r
1050 * THIS FUNCTION MUST NOT BE USED FROM APPLICATION CODE. IT IS ONLY
\r
1051 * INTENDED FOR USE WHEN IMPLEMENTING A PORT OF THE SCHEDULER AND IS
\r
1052 * AN INTERFACE WHICH IS FOR THE EXCLUSIVE USE OF THE SCHEDULER.
\r
1054 * Sets the pointer to the current TCB to the TCB of the highest priority task
\r
1055 * that is ready to run.
\r
1057 void vTaskSwitchContext( void );
\r
1060 * Return the handle of the calling task.
\r
1062 xTaskHandle xTaskGetCurrentTaskHandle( void );
\r
1065 * Capture the current time status for future reference.
\r
1067 void vTaskSetTimeOutState( xTimeOutType * const pxTimeOut );
\r
1070 * Compare the time status now with that previously captured to see if the
\r
1071 * timeout has expired.
\r
1073 portBASE_TYPE xTaskCheckForTimeOut( xTimeOutType * const pxTimeOut, portTickType * const pxTicksToWait );
\r
1076 * Shortcut used by the queue implementation to prevent unnecessary call to
\r
1079 void vTaskMissedYield( void );
\r
1082 * Returns the scheduler state as taskSCHEDULER_RUNNING,
\r
1083 * taskSCHEDULER_NOT_STARTED or taskSCHEDULER_SUSPENDED.
\r
1085 portBASE_TYPE xTaskGetSchedulerState( void );
\r
1088 * Raises the priority of the mutex holder to that of the calling task should
\r
1089 * the mutex holder have a priority less than the calling task.
\r
1091 void vTaskPriorityInherit( xTaskHandle * const pxMutexHolder );
\r
1094 * Set the priority of a task back to its proper priority in the case that it
\r
1095 * inherited a higher priority while it was holding a semaphore.
\r
1097 void vTaskPriorityDisinherit( xTaskHandle * const pxMutexHolder );
\r
1099 #ifdef __cplusplus
\r
1102 #endif /* TASK_H */
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