2 FreeRTOS.org V5.2.0 - 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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10 FreeRTOS.org is distributed in the hope that it will be useful, but WITHOUT
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11 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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12 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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15 You should have received a copy of the GNU General Public License along
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16 with FreeRTOS.org; if not, write to the Free Software Foundation, Inc., 59
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17 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
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19 A special exception to the GPL is included to allow you to distribute a
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20 combined work that includes FreeRTOS.org without being obliged to provide
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21 the source code for any proprietary components. See the licensing section
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22 of http://www.FreeRTOS.org for full details.
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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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68 /*-----------------------------------------------------------
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69 * MACROS AND DEFINITIONS
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70 *----------------------------------------------------------*/
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72 #define tskKERNEL_VERSION_NUMBER "V5.1.0"
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77 * Type by which tasks are referenced. For example, a call to xTaskCreate
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78 * returns (via a pointer parameter) an xTaskHandle variable that can then
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79 * be used as a parameter to vTaskDelete to delete the task.
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81 * \page xTaskHandle xTaskHandle
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84 typedef void * xTaskHandle;
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87 * Used internally only.
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89 typedef struct xTIME_OUT
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91 portBASE_TYPE xOverflowCount;
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92 portTickType xTimeOnEntering;
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96 * Defines the priority used by the idle task. This must not be modified.
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98 * \ingroup TaskUtils
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100 #define tskIDLE_PRIORITY ( ( unsigned portBASE_TYPE ) 0 )
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105 * Macro for forcing a context switch.
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107 * \page taskYIELD taskYIELD
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108 * \ingroup SchedulerControl
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110 #define taskYIELD() portYIELD()
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115 * Macro to mark the start of a critical code region. Preemptive context
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116 * switches cannot occur when in a critical region.
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118 * NOTE: This may alter the stack (depending on the portable implementation)
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119 * so must be used with care!
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121 * \page taskENTER_CRITICAL taskENTER_CRITICAL
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122 * \ingroup SchedulerControl
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124 #define taskENTER_CRITICAL() portENTER_CRITICAL()
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129 * Macro to mark the end of a critical code region. Preemptive context
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130 * switches cannot occur when in a critical region.
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132 * NOTE: This may alter the stack (depending on the portable implementation)
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133 * so must be used with care!
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135 * \page taskEXIT_CRITICAL taskEXIT_CRITICAL
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136 * \ingroup SchedulerControl
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138 #define taskEXIT_CRITICAL() portEXIT_CRITICAL()
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143 * Macro to disable all maskable interrupts.
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145 * \page taskDISABLE_INTERRUPTS taskDISABLE_INTERRUPTS
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146 * \ingroup SchedulerControl
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148 #define taskDISABLE_INTERRUPTS() portDISABLE_INTERRUPTS()
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153 * Macro to enable microcontroller interrupts.
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155 * \page taskENABLE_INTERRUPTS taskENABLE_INTERRUPTS
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156 * \ingroup SchedulerControl
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158 #define taskENABLE_INTERRUPTS() portENABLE_INTERRUPTS()
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160 /* Definitions returned by xTaskGetSchedulerState(). */
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161 #define taskSCHEDULER_NOT_STARTED 0
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162 #define taskSCHEDULER_RUNNING 1
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163 #define taskSCHEDULER_SUSPENDED 2
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165 /*-----------------------------------------------------------
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166 * TASK CREATION API
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167 *----------------------------------------------------------*/
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172 portBASE_TYPE xTaskCreate(
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173 pdTASK_CODE pvTaskCode,
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174 const portCHAR * const pcName,
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175 unsigned portSHORT usStackDepth,
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176 void *pvParameters,
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177 unsigned portBASE_TYPE uxPriority,
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178 xTaskHandle *pvCreatedTask
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181 * Create a new task and add it to the list of tasks that are ready to run.
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183 * @param pvTaskCode Pointer to the task entry function. Tasks
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184 * must be implemented to never return (i.e. continuous loop).
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186 * @param pcName A descriptive name for the task. This is mainly used to
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187 * facilitate debugging. Max length defined by tskMAX_TASK_NAME_LEN - default
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190 * @param usStackDepth The size of the task stack specified as the number of
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191 * variables the stack can hold - not the number of bytes. For example, if
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192 * the stack is 16 bits wide and usStackDepth is defined as 100, 200 bytes
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193 * will be allocated for stack storage.
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195 * @param pvParameters Pointer that will be used as the parameter for the task
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198 * @param uxPriority The priority at which the task should run.
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200 * @param pvCreatedTask Used to pass back a handle by which the created task
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201 * can be referenced.
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203 * @return pdPASS if the task was successfully created and added to a ready
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204 * list, otherwise an error code defined in the file errors. h
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208 // Task to be created.
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209 void vTaskCode( void * pvParameters )
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213 // Task code goes here.
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217 // Function that creates a task.
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218 void vOtherFunction( void )
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220 static unsigned char ucParameterToPass;
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221 xTaskHandle xHandle;
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223 // Create the task, storing the handle. Note that the passed parameter ucParameterToPass
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224 // must exist for the lifetime of the task, so in this case is declared static. If it was just an
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225 // an automatic stack variable it might no longer exist, or at least have been corrupted, by the time
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226 // the new time attempts to access it.
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227 xTaskCreate( vTaskCode, "NAME", STACK_SIZE, &ucParameterToPass, tskIDLE_PRIORITY, &xHandle );
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229 // Use the handle to delete the task.
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230 vTaskDelete( xHandle );
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233 * \defgroup xTaskCreate xTaskCreate
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236 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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240 * <pre>void vTaskDelete( xTaskHandle pxTask );</pre>
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242 * INCLUDE_vTaskDelete must be defined as 1 for this function to be available.
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243 * See the configuration section for more information.
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245 * Remove a task from the RTOS real time kernels management. The task being
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246 * deleted will be removed from all ready, blocked, suspended and event lists.
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248 * NOTE: The idle task is responsible for freeing the kernel allocated
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249 * memory from tasks that have been deleted. It is therefore important that
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250 * the idle task is not starved of microcontroller processing time if your
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251 * application makes any calls to vTaskDelete (). Memory allocated by the
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252 * task code is not automatically freed, and should be freed before the task
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255 * See the demo application file death.c for sample code that utilises
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258 * @param pxTask The handle of the task to be deleted. Passing NULL will
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259 * cause the calling task to be deleted.
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263 void vOtherFunction( void )
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265 xTaskHandle xHandle;
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267 // Create the task, storing the handle.
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268 xTaskCreate( vTaskCode, "NAME", STACK_SIZE, NULL, tskIDLE_PRIORITY, &xHandle );
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270 // Use the handle to delete the task.
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271 vTaskDelete( xHandle );
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274 * \defgroup vTaskDelete vTaskDelete
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277 void vTaskDelete( xTaskHandle pxTask );
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280 /*-----------------------------------------------------------
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282 *----------------------------------------------------------*/
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286 * <pre>void vTaskDelay( portTickType xTicksToDelay );</pre>
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288 * Delay a task for a given number of ticks. The actual time that the
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289 * task remains blocked depends on the tick rate. The constant
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290 * portTICK_RATE_MS can be used to calculate real time from the tick
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291 * rate - with the resolution of one tick period.
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293 * INCLUDE_vTaskDelay must be defined as 1 for this function to be available.
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294 * See the configuration section for more information.
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297 * vTaskDelay() specifies a time at which the task wishes to unblock relative to
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298 * the time at which vTaskDelay() is called. For example, specifying a block
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299 * period of 100 ticks will cause the task to unblock 100 ticks after
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300 * vTaskDelay() is called. vTaskDelay() does not therefore provide a good method
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301 * of controlling the frequency of a cyclical task as the path taken through the
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302 * code, as well as other task and interrupt activity, will effect the frequency
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303 * at which vTaskDelay() gets called and therefore the time at which the task
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304 * next executes. See vTaskDelayUntil() for an alternative API function designed
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305 * to facilitate fixed frequency execution. It does this by specifying an
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306 * absolute time (rather than a relative time) at which the calling task should
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309 * @param xTicksToDelay The amount of time, in tick periods, that
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310 * the calling task should block.
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314 void vTaskFunction( void * pvParameters )
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316 void vTaskFunction( void * pvParameters )
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318 // Block for 500ms.
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319 const portTickType xDelay = 500 / portTICK_RATE_MS;
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323 // Simply toggle the LED every 500ms, blocking between each toggle.
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325 vTaskDelay( xDelay );
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329 * \defgroup vTaskDelay vTaskDelay
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330 * \ingroup TaskCtrl
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332 void vTaskDelay( portTickType xTicksToDelay );
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336 * <pre>void vTaskDelayUntil( portTickType *pxPreviousWakeTime, portTickType xTimeIncrement );</pre>
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338 * INCLUDE_vTaskDelayUntil must be defined as 1 for this function to be available.
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339 * See the configuration section for more information.
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341 * Delay a task until a specified time. This function can be used by cyclical
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342 * tasks to ensure a constant execution frequency.
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344 * This function differs from vTaskDelay () in one important aspect: vTaskDelay () will
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345 * cause a task to block for the specified number of ticks from the time vTaskDelay () is
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346 * called. It is therefore difficult to use vTaskDelay () by itself to generate a fixed
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347 * execution frequency as the time between a task starting to execute and that task
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348 * calling vTaskDelay () may not be fixed [the task may take a different path though the
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349 * code between calls, or may get interrupted or preempted a different number of times
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350 * each time it executes].
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352 * Whereas vTaskDelay () specifies a wake time relative to the time at which the function
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353 * is called, vTaskDelayUntil () specifies the absolute (exact) time at which it wishes to
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356 * The constant portTICK_RATE_MS can be used to calculate real time from the tick
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357 * rate - with the resolution of one tick period.
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359 * @param pxPreviousWakeTime Pointer to a variable that holds the time at which the
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360 * task was last unblocked. The variable must be initialised with the current time
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361 * prior to its first use (see the example below). Following this the variable is
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362 * automatically updated within vTaskDelayUntil ().
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364 * @param xTimeIncrement The cycle time period. The task will be unblocked at
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365 * time *pxPreviousWakeTime + xTimeIncrement. Calling vTaskDelayUntil with the
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366 * same xTimeIncrement parameter value will cause the task to execute with
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367 * a fixed interface period.
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371 // Perform an action every 10 ticks.
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372 void vTaskFunction( void * pvParameters )
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374 portTickType xLastWakeTime;
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375 const portTickType xFrequency = 10;
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377 // Initialise the xLastWakeTime variable with the current time.
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378 xLastWakeTime = xTaskGetTickCount ();
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381 // Wait for the next cycle.
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382 vTaskDelayUntil( &xLastWakeTime, xFrequency );
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384 // Perform action here.
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388 * \defgroup vTaskDelayUntil vTaskDelayUntil
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389 * \ingroup TaskCtrl
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391 void vTaskDelayUntil( portTickType * const pxPreviousWakeTime, portTickType xTimeIncrement );
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395 * <pre>unsigned portBASE_TYPE uxTaskPriorityGet( xTaskHandle pxTask );</pre>
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397 * INCLUDE_xTaskPriorityGet must be defined as 1 for this function to be available.
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398 * See the configuration section for more information.
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400 * Obtain the priority of any task.
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402 * @param pxTask Handle of the task to be queried. Passing a NULL
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403 * handle results in the priority of the calling task being returned.
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405 * @return The priority of pxTask.
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409 void vAFunction( void )
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411 xTaskHandle xHandle;
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413 // Create a task, storing the handle.
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414 xTaskCreate( vTaskCode, "NAME", STACK_SIZE, NULL, tskIDLE_PRIORITY, &xHandle );
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418 // Use the handle to obtain the priority of the created task.
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419 // It was created with tskIDLE_PRIORITY, but may have changed
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421 if( uxTaskPriorityGet( xHandle ) != tskIDLE_PRIORITY )
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423 // The task has changed it's priority.
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428 // Is our priority higher than the created task?
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429 if( uxTaskPriorityGet( xHandle ) < uxTaskPriorityGet( NULL ) )
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431 // Our priority (obtained using NULL handle) is higher.
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435 * \defgroup uxTaskPriorityGet uxTaskPriorityGet
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436 * \ingroup TaskCtrl
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438 unsigned portBASE_TYPE uxTaskPriorityGet( xTaskHandle pxTask );
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442 * <pre>void vTaskPrioritySet( xTaskHandle pxTask, unsigned portBASE_TYPE uxNewPriority );</pre>
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444 * INCLUDE_vTaskPrioritySet must be defined as 1 for this function to be available.
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445 * See the configuration section for more information.
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447 * Set the priority of any task.
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449 * A context switch will occur before the function returns if the priority
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450 * being set is higher than the currently executing task.
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452 * @param pxTask Handle to the task for which the priority is being set.
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453 * Passing a NULL handle results in the priority of the calling task being set.
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455 * @param uxNewPriority The priority to which the task will be set.
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459 void vAFunction( void )
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461 xTaskHandle xHandle;
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463 // Create a task, storing the handle.
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464 xTaskCreate( vTaskCode, "NAME", STACK_SIZE, NULL, tskIDLE_PRIORITY, &xHandle );
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468 // Use the handle to raise the priority of the created task.
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469 vTaskPrioritySet( xHandle, tskIDLE_PRIORITY + 1 );
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473 // Use a NULL handle to raise our priority to the same value.
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474 vTaskPrioritySet( NULL, tskIDLE_PRIORITY + 1 );
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477 * \defgroup vTaskPrioritySet vTaskPrioritySet
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478 * \ingroup TaskCtrl
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480 void vTaskPrioritySet( xTaskHandle pxTask, unsigned portBASE_TYPE uxNewPriority );
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484 * <pre>void vTaskSuspend( xTaskHandle pxTaskToSuspend );</pre>
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486 * INCLUDE_vTaskSuspend must be defined as 1 for this function to be available.
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487 * See the configuration section for more information.
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489 * Suspend any task. When suspended a task will never get any microcontroller
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490 * processing time, no matter what its priority.
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492 * Calls to vTaskSuspend are not accumulative -
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493 * i.e. calling vTaskSuspend () twice on the same task still only requires one
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494 * call to vTaskResume () to ready the suspended task.
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496 * @param pxTaskToSuspend Handle to the task being suspended. Passing a NULL
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497 * handle will cause the calling task to be suspended.
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501 void vAFunction( void )
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503 xTaskHandle xHandle;
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505 // Create a task, storing the handle.
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506 xTaskCreate( vTaskCode, "NAME", STACK_SIZE, NULL, tskIDLE_PRIORITY, &xHandle );
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510 // Use the handle to suspend the created task.
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511 vTaskSuspend( xHandle );
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515 // The created task will not run during this period, unless
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516 // another task calls vTaskResume( xHandle ).
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521 // Suspend ourselves.
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522 vTaskSuspend( NULL );
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524 // We cannot get here unless another task calls vTaskResume
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525 // with our handle as the parameter.
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528 * \defgroup vTaskSuspend vTaskSuspend
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529 * \ingroup TaskCtrl
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531 void vTaskSuspend( xTaskHandle pxTaskToSuspend );
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535 * <pre>void vTaskResume( xTaskHandle pxTaskToResume );</pre>
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537 * INCLUDE_vTaskSuspend must be defined as 1 for this function to be available.
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538 * See the configuration section for more information.
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540 * Resumes a suspended task.
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542 * A task that has been suspended by one of more calls to vTaskSuspend ()
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543 * will be made available for running again by a single call to
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546 * @param pxTaskToResume Handle to the task being readied.
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550 void vAFunction( void )
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552 xTaskHandle xHandle;
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554 // Create a task, storing the handle.
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555 xTaskCreate( vTaskCode, "NAME", STACK_SIZE, NULL, tskIDLE_PRIORITY, &xHandle );
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559 // Use the handle to suspend the created task.
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560 vTaskSuspend( xHandle );
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564 // The created task will not run during this period, unless
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565 // another task calls vTaskResume( xHandle ).
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570 // Resume the suspended task ourselves.
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571 vTaskResume( xHandle );
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573 // The created task will once again get microcontroller processing
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574 // time in accordance with it priority within the system.
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577 * \defgroup vTaskResume vTaskResume
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578 * \ingroup TaskCtrl
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580 void vTaskResume( xTaskHandle pxTaskToResume );
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584 * <pre>void xTaskResumeFromISR( xTaskHandle pxTaskToResume );</pre>
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586 * INCLUDE_xTaskResumeFromISR must be defined as 1 for this function to be
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587 * available. See the configuration section for more information.
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589 * An implementation of vTaskResume() that can be called from within an ISR.
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591 * A task that has been suspended by one of more calls to vTaskSuspend ()
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592 * will be made available for running again by a single call to
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593 * xTaskResumeFromISR ().
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595 * @param pxTaskToResume Handle to the task being readied.
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597 * \defgroup vTaskResumeFromISR vTaskResumeFromISR
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598 * \ingroup TaskCtrl
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600 portBASE_TYPE xTaskResumeFromISR( xTaskHandle pxTaskToResume );
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602 /*-----------------------------------------------------------
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603 * SCHEDULER CONTROL
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604 *----------------------------------------------------------*/
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608 * <pre>void vTaskStartScheduler( void );</pre>
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610 * Starts the real time kernel tick processing. After calling the kernel
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611 * has control over which tasks are executed and when. This function
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612 * does not return until an executing task calls vTaskEndScheduler ().
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614 * At least one task should be created via a call to xTaskCreate ()
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615 * before calling vTaskStartScheduler (). The idle task is created
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616 * automatically when the first application task is created.
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618 * See the demo application file main.c for an example of creating
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619 * tasks and starting the kernel.
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623 void vAFunction( void )
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625 // Create at least one task before starting the kernel.
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626 xTaskCreate( vTaskCode, "NAME", STACK_SIZE, NULL, tskIDLE_PRIORITY, NULL );
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628 // Start the real time kernel with preemption.
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629 vTaskStartScheduler ();
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631 // Will not get here unless a task calls vTaskEndScheduler ()
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635 * \defgroup vTaskStartScheduler vTaskStartScheduler
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636 * \ingroup SchedulerControl
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638 void vTaskStartScheduler( void );
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642 * <pre>void vTaskEndScheduler( void );</pre>
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644 * Stops the real time kernel tick. All created tasks will be automatically
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645 * deleted and multitasking (either preemptive or cooperative) will
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646 * stop. Execution then resumes from the point where vTaskStartScheduler ()
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647 * was called, as if vTaskStartScheduler () had just returned.
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649 * See the demo application file main. c in the demo/PC directory for an
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650 * example that uses vTaskEndScheduler ().
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652 * vTaskEndScheduler () requires an exit function to be defined within the
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653 * portable layer (see vPortEndScheduler () in port. c for the PC port). This
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654 * performs hardware specific operations such as stopping the kernel tick.
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656 * vTaskEndScheduler () will cause all of the resources allocated by the
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657 * kernel to be freed - but will not free resources allocated by application
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662 void vTaskCode( void * pvParameters )
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666 // Task code goes here.
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668 // At some point we want to end the real time kernel processing
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670 vTaskEndScheduler ();
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674 void vAFunction( void )
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676 // Create at least one task before starting the kernel.
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677 xTaskCreate( vTaskCode, "NAME", STACK_SIZE, NULL, tskIDLE_PRIORITY, NULL );
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679 // Start the real time kernel with preemption.
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680 vTaskStartScheduler ();
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682 // Will only get here when the vTaskCode () task has called
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683 // vTaskEndScheduler (). When we get here we are back to single task
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688 * \defgroup vTaskEndScheduler vTaskEndScheduler
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689 * \ingroup SchedulerControl
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691 void vTaskEndScheduler( void );
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695 * <pre>void vTaskSuspendAll( void );</pre>
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697 * Suspends all real time kernel activity while keeping interrupts (including the
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698 * kernel tick) enabled.
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700 * After calling vTaskSuspendAll () the calling task will continue to execute
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701 * without risk of being swapped out until a call to xTaskResumeAll () has been
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704 * API functions that have the potential to cause a context switch (for example,
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705 * vTaskDelayUntil(), xQueueSend(), etc.) must not be called while the scheduler
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710 void vTask1( void * pvParameters )
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714 // Task code goes here.
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718 // At some point the task wants to perform a long operation during
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719 // which it does not want to get swapped out. It cannot use
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720 // taskENTER_CRITICAL ()/taskEXIT_CRITICAL () as the length of the
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721 // operation may cause interrupts to be missed - including the
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724 // Prevent the real time kernel swapping out the task.
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725 vTaskSuspendAll ();
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727 // Perform the operation here. There is no need to use critical
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728 // sections as we have all the microcontroller processing time.
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729 // During this time interrupts will still operate and the kernel
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730 // tick count will be maintained.
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734 // The operation is complete. Restart the kernel.
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739 * \defgroup vTaskSuspendAll vTaskSuspendAll
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740 * \ingroup SchedulerControl
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742 void vTaskSuspendAll( void );
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746 * <pre>portCHAR xTaskResumeAll( void );</pre>
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748 * Resumes real time kernel activity following a call to vTaskSuspendAll ().
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749 * After a call to vTaskSuspendAll () the kernel will take control of which
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750 * task is executing at any time.
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752 * @return If resuming the scheduler caused a context switch then pdTRUE is
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753 * returned, otherwise pdFALSE is returned.
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757 void vTask1( void * pvParameters )
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761 // Task code goes here.
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765 // At some point the task wants to perform a long operation during
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766 // which it does not want to get swapped out. It cannot use
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767 // taskENTER_CRITICAL ()/taskEXIT_CRITICAL () as the length of the
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768 // operation may cause interrupts to be missed - including the
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771 // Prevent the real time kernel swapping out the task.
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772 vTaskSuspendAll ();
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774 // Perform the operation here. There is no need to use critical
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775 // sections as we have all the microcontroller processing time.
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776 // During this time interrupts will still operate and the real
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777 // time kernel tick count will be maintained.
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781 // The operation is complete. Restart the kernel. We want to force
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782 // a context switch - but there is no point if resuming the scheduler
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783 // caused a context switch already.
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784 if( !xTaskResumeAll () )
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791 * \defgroup xTaskResumeAll xTaskResumeAll
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792 * \ingroup SchedulerControl
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794 signed portBASE_TYPE xTaskResumeAll( void );
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798 * <pre>signed portBASE_TYPE xTaskIsTaskSuspended( xTaskHandle xTask );</pre>
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800 * Utility task that simply returns pdTRUE if the task referenced by xTask is
\r
801 * currently in the Suspended state, or pdFALSE if the task referenced by xTask
\r
802 * is in any other state.
\r
805 signed portBASE_TYPE xTaskIsTaskSuspended( xTaskHandle xTask );
\r
807 /*-----------------------------------------------------------
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809 *----------------------------------------------------------*/
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813 * <PRE>volatile portTickType xTaskGetTickCount( void );</PRE>
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815 * @return The count of ticks since vTaskStartScheduler was called.
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817 * \page xTaskGetTickCount xTaskGetTickCount
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818 * \ingroup TaskUtils
\r
820 portTickType xTaskGetTickCount( void );
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824 * <PRE>unsigned portSHORT uxTaskGetNumberOfTasks( void );</PRE>
\r
826 * @return The number of tasks that the real time kernel is currently managing.
\r
827 * This includes all ready, blocked and suspended tasks. A task that
\r
828 * has been deleted but not yet freed by the idle task will also be
\r
829 * included in the count.
\r
831 * \page uxTaskGetNumberOfTasks uxTaskGetNumberOfTasks
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832 * \ingroup TaskUtils
\r
834 unsigned portBASE_TYPE uxTaskGetNumberOfTasks( void );
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838 * <PRE>void vTaskList( portCHAR *pcWriteBuffer );</PRE>
\r
840 * configUSE_TRACE_FACILITY must be defined as 1 for this function to be
\r
841 * available. See the configuration section for more information.
\r
843 * NOTE: This function will disable interrupts for its duration. It is
\r
844 * not intended for normal application runtime use but as a debug aid.
\r
846 * Lists all the current tasks, along with their current state and stack
\r
847 * usage high water mark.
\r
849 * Tasks are reported as blocked ('B'), ready ('R'), deleted ('D') or
\r
852 * @param pcWriteBuffer A buffer into which the above mentioned details
\r
853 * will be written, in ascii form. This buffer is assumed to be large
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854 * enough to contain the generated report. Approximately 40 bytes per
\r
855 * task should be sufficient.
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857 * \page vTaskList vTaskList
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858 * \ingroup TaskUtils
\r
860 void vTaskList( signed portCHAR *pcWriteBuffer );
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864 * <PRE>void vTaskGetRunTimeStats( portCHAR *pcWriteBuffer );</PRE>
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866 * configGENERATE_RUN_TIME_STATS must be defined as 1 for this function
\r
867 * to be available. The application must also then provide definitions
\r
868 * for portCONFIGURE_TIMER_FOR_RUN_TIME_STATS() and
\r
869 * portGET_RUN_TIME_COUNTER_VALUE to configure a peripheral timer/counter
\r
870 * and return the timers current count value respectively. A 1uS timer
\r
871 * frequency is recommended for a 32bit peripheral counter - this will
\r
872 * allow the statistics to be gathered over the first (approximately) 70
\r
873 * minutes of execution.
\r
875 * NOTE: This function will disable interrupts for its duration. It is
\r
876 * not intended for normal application runtime use but as a debug aid.
\r
878 * Setting configGENERATE_RUN_TIME_STATS to 1 will result in a total
\r
879 * accumulated execution time being stored for each task. The resolution
\r
880 * of the accumulated time value depends on the frequency of the timer
\r
881 * configured by the portCONFIGURE_TIMER_FOR_RUN_TIME_STATS() macro.
\r
882 * Calling vTaskGetRunTimeStats() writes the total execution time of each
\r
883 * task into a buffer, both as an absolute count value and as a percentage
\r
884 * of the total system execution time.
\r
886 * @param pcWriteBuffer A buffer into which the execution times will be
\r
887 * written, in ascii form. This buffer is assumed to be large enough to
\r
888 * contain the generated report. Approximately 40 bytes per task should
\r
891 * \page vTaskGetRunTimeStats vTaskGetRunTimeStats
\r
892 * \ingroup TaskUtils
\r
894 void vTaskGetRunTimeStats( signed portCHAR *pcWriteBuffer );
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898 * <PRE>void vTaskStartTrace( portCHAR * pcBuffer, unsigned portBASE_TYPE uxBufferSize );</PRE>
\r
900 * Starts a real time kernel activity trace. The trace logs the identity of
\r
901 * which task is running when.
\r
903 * The trace file is stored in binary format. A separate DOS utility called
\r
904 * convtrce.exe is used to convert this into a tab delimited text file which
\r
905 * can be viewed and plotted in a spread sheet.
\r
907 * @param pcBuffer The buffer into which the trace will be written.
\r
909 * @param ulBufferSize The size of pcBuffer in bytes. The trace will continue
\r
910 * until either the buffer in full, or ulTaskEndTrace () is called.
\r
912 * \page vTaskStartTrace vTaskStartTrace
\r
913 * \ingroup TaskUtils
\r
915 void vTaskStartTrace( signed portCHAR * pcBuffer, unsigned portLONG ulBufferSize );
\r
919 * <PRE>unsigned portLONG ulTaskEndTrace( void );</PRE>
\r
921 * Stops a kernel activity trace. See vTaskStartTrace ().
\r
923 * @return The number of bytes that have been written into the trace buffer.
\r
925 * \page usTaskEndTrace usTaskEndTrace
\r
926 * \ingroup TaskUtils
\r
928 unsigned portLONG ulTaskEndTrace( void );
\r
932 * <PRE>unsigned portBASE_TYPE uxTaskGetStackHighWaterMark( xTaskHandle xTask );</PRE>
\r
934 * INCLUDE_uxTaskGetStackHighWaterMark must be set to 1 in FreeRTOSConfig.h for
\r
935 * this function to be available.
\r
937 * Returns the high water mark of the stack associated with xTask. That is,
\r
938 * the minimum free stack space there has been (in bytes) since the task
\r
939 * started. The smaller the returned number the closer the task has come
\r
940 * to overflowing its stack.
\r
942 * @param xTask Handle of the task associated with the stack to be checked.
\r
943 * Set xTask to NULL to check the stack of the calling task.
\r
945 * @return The smallest amount of free stack space there has been (in bytes)
\r
946 * since the task referenced by xTask was created.
\r
948 unsigned portBASE_TYPE uxTaskGetStackHighWaterMark( xTaskHandle xTask );
\r
952 * <pre>void vTaskSetApplicationTaskTag( xTaskHandle xTask, pdTASK_HOOK_CODE pxHookFunction );</pre>
\r
954 * Sets pxHookFunction to be the task hook function used by the task xTask.
\r
955 * Passing xTask as NULL has the effect of setting the calling tasks hook
\r
958 void vTaskSetApplicationTaskTag( xTaskHandle xTask, pdTASK_HOOK_CODE pxHookFunction );
\r
962 * <pre>portBASE_TYPE xTaskCallApplicationTaskHook( xTaskHandle xTask, pdTASK_HOOK_CODE pxHookFunction );</pre>
\r
964 * Calls the hook function associated with xTask. Passing xTask as NULL has
\r
965 * the effect of calling the Running tasks (the calling task) hook function.
\r
967 * pvParameter is passed to the hook function for the task to interpret as it
\r
970 portBASE_TYPE xTaskCallApplicationTaskHook( xTaskHandle xTask, void *pvParameter );
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973 /*-----------------------------------------------------------
\r
974 * SCHEDULER INTERNALS AVAILABLE FOR PORTING PURPOSES
\r
975 *----------------------------------------------------------*/
\r
978 * THIS FUNCTION MUST NOT BE USED FROM APPLICATION CODE. IT IS ONLY
\r
979 * INTENDED FOR USE WHEN IMPLEMENTING A PORT OF THE SCHEDULER AND IS
\r
980 * AN INTERFACE WHICH IS FOR THE EXCLUSIVE USE OF THE SCHEDULER.
\r
982 * Called from the real time kernel tick (either preemptive or cooperative),
\r
983 * this increments the tick count and checks if any tasks that are blocked
\r
984 * for a finite period required removing from a blocked list and placing on
\r
987 void vTaskIncrementTick( void );
\r
990 * THIS FUNCTION MUST NOT BE USED FROM APPLICATION CODE. IT IS AN
\r
991 * INTERFACE WHICH IS FOR THE EXCLUSIVE USE OF THE SCHEDULER.
\r
993 * THIS FUNCTION MUST BE CALLED WITH INTERRUPTS DISABLED.
\r
995 * Removes the calling task from the ready list and places it both
\r
996 * on the list of tasks waiting for a particular event, and the
\r
997 * list of delayed tasks. The task will be removed from both lists
\r
998 * and replaced on the ready list should either the event occur (and
\r
999 * there be no higher priority tasks waiting on the same event) or
\r
1000 * the delay period expires.
\r
1002 * @param pxEventList The list containing tasks that are blocked waiting
\r
1003 * for the event to occur.
\r
1005 * @param xTicksToWait The maximum amount of time that the task should wait
\r
1006 * for the event to occur. This is specified in kernel ticks,the constant
\r
1007 * portTICK_RATE_MS can be used to convert kernel ticks into a real time
\r
1010 void vTaskPlaceOnEventList( const xList * const pxEventList, portTickType xTicksToWait );
\r
1013 * THIS FUNCTION MUST NOT BE USED FROM APPLICATION CODE. IT IS AN
\r
1014 * INTERFACE WHICH IS FOR THE EXCLUSIVE USE OF THE SCHEDULER.
\r
1016 * THIS FUNCTION MUST BE CALLED WITH INTERRUPTS DISABLED.
\r
1018 * Removes a task from both the specified event list and the list of blocked
\r
1019 * tasks, and places it on a ready queue.
\r
1021 * xTaskRemoveFromEventList () will be called if either an event occurs to
\r
1022 * unblock a task, or the block timeout period expires.
\r
1024 * @return pdTRUE if the task being removed has a higher priority than the task
\r
1025 * making the call, otherwise pdFALSE.
\r
1027 signed portBASE_TYPE xTaskRemoveFromEventList( const xList * const pxEventList );
\r
1030 * THIS FUNCTION MUST NOT BE USED FROM APPLICATION CODE. IT IS AN
\r
1031 * INTERFACE WHICH IS FOR THE EXCLUSIVE USE OF THE SCHEDULER.
\r
1033 * INCLUDE_vTaskCleanUpResources and INCLUDE_vTaskSuspend must be defined as 1
\r
1034 * for this function to be available.
\r
1035 * See the configuration section for more information.
\r
1037 * Empties the ready and delayed queues of task control blocks, freeing the
\r
1038 * memory allocated for the task control block and task stacks as it goes.
\r
1040 void vTaskCleanUpResources( void );
\r
1043 * THIS FUNCTION MUST NOT BE USED FROM APPLICATION CODE. IT IS ONLY
\r
1044 * INTENDED FOR USE WHEN IMPLEMENTING A PORT OF THE SCHEDULER AND IS
\r
1045 * AN INTERFACE WHICH IS FOR THE EXCLUSIVE USE OF THE SCHEDULER.
\r
1047 * Sets the pointer to the current TCB to the TCB of the highest priority task
\r
1048 * that is ready to run.
\r
1050 void vTaskSwitchContext( void );
\r
1053 * Return the handle of the calling task.
\r
1055 xTaskHandle xTaskGetCurrentTaskHandle( void );
\r
1058 * Capture the current time status for future reference.
\r
1060 void vTaskSetTimeOutState( xTimeOutType * const pxTimeOut );
\r
1063 * Compare the time status now with that previously captured to see if the
\r
1064 * timeout has expired.
\r
1066 portBASE_TYPE xTaskCheckForTimeOut( xTimeOutType * const pxTimeOut, portTickType * const pxTicksToWait );
\r
1069 * Shortcut used by the queue implementation to prevent unnecessary call to
\r
1072 void vTaskMissedYield( void );
\r
1075 * Returns the scheduler state as taskSCHEDULER_RUNNING,
\r
1076 * taskSCHEDULER_NOT_STARTED or taskSCHEDULER_SUSPENDED.
\r
1078 portBASE_TYPE xTaskGetSchedulerState( void );
\r
1081 * Raises the priority of the mutex holder to that of the calling task should
\r
1082 * the mutex holder have a priority less than the calling task.
\r
1084 void vTaskPriorityInherit( xTaskHandle * const pxMutexHolder );
\r
1087 * Set the priority of a task back to its proper priority in the case that it
\r
1088 * inherited a higher priority while it was holding a semaphore.
\r
1090 void vTaskPriorityDisinherit( xTaskHandle * const pxMutexHolder );
\r
1092 #ifdef __cplusplus
\r
1095 #endif /* TASK_H */
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