2 FreeRTOS V7.0.0 - Copyright (C) 2011 Real Time Engineers Ltd.
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5 FreeRTOS supports many tools and architectures. V7.0.0 is sponsored by:
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6 Atollic AB - Atollic provides professional embedded systems development
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7 tools for C/C++ development, code analysis and test automation.
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8 See http://www.atollic.com
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11 ***************************************************************************
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13 * FreeRTOS tutorial books are available in pdf and paperback. *
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14 * Complete, revised, and edited pdf reference manuals are also *
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17 * Purchasing FreeRTOS documentation will not only help you, by *
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18 * ensuring you get running as quickly as possible and with an *
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19 * in-depth knowledge of how to use FreeRTOS, it will also help *
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20 * the FreeRTOS project to continue with its mission of providing *
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21 * professional grade, cross platform, de facto standard solutions *
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22 * for microcontrollers - completely free of charge! *
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24 * >>> See http://www.FreeRTOS.org/Documentation for details. <<< *
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26 * Thank you for using FreeRTOS, and thank you for your support! *
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28 ***************************************************************************
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31 This file is part of the FreeRTOS distribution.
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33 FreeRTOS is free software; you can redistribute it and/or modify it under
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34 the terms of the GNU General Public License (version 2) as published by the
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35 Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
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36 >>>NOTE<<< The modification to the GPL is included to allow you to
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37 distribute a combined work that includes FreeRTOS without being obliged to
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38 provide the source code for proprietary components outside of the FreeRTOS
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39 kernel. FreeRTOS is distributed in the hope that it will be useful, but
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40 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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41 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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42 more details. You should have received a copy of the GNU General Public
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43 License and the FreeRTOS license exception along with FreeRTOS; if not it
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44 can be viewed here: http://www.freertos.org/a00114.html and also obtained
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45 by writing to Richard Barry, contact details for whom are available on the
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50 http://www.FreeRTOS.org - Documentation, latest information, license and
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53 http://www.SafeRTOS.com - A version that is certified for use in safety
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56 http://www.OpenRTOS.com - Commercial support, development, porting,
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57 licensing and training services.
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64 #ifndef INC_FREERTOS_H
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65 #error "#include FreeRTOS.h" must appear in source files before "#include queue.h"
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73 #include "mpu_wrappers.h"
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76 * Type by which queues are referenced. For example, a call to xQueueCreate
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77 * returns (via a pointer parameter) an xQueueHandle variable that can then
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78 * be used as a parameter to xQueueSend(), xQueueReceive(), etc.
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80 typedef void * xQueueHandle;
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83 /* For internal use only. */
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84 #define queueSEND_TO_BACK ( 0 )
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85 #define queueSEND_TO_FRONT ( 1 )
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91 xQueueHandle xQueueCreate(
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92 unsigned portBASE_TYPE uxQueueLength,
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93 unsigned portBASE_TYPE uxItemSize
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97 * Creates a new queue instance. This allocates the storage required by the
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98 * new queue and returns a handle for the queue.
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100 * @param uxQueueLength The maximum number of items that the queue can contain.
\r
102 * @param uxItemSize The number of bytes each item in the queue will require.
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103 * Items are queued by copy, not by reference, so this is the number of bytes
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104 * that will be copied for each posted item. Each item on the queue must be
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107 * @return If the queue is successfully create then a handle to the newly
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108 * created queue is returned. If the queue cannot be created then 0 is
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119 void vATask( void *pvParameters )
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121 xQueueHandle xQueue1, xQueue2;
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123 // Create a queue capable of containing 10 unsigned long values.
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124 xQueue1 = xQueueCreate( 10, sizeof( unsigned long ) );
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127 // Queue was not created and must not be used.
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130 // Create a queue capable of containing 10 pointers to AMessage structures.
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131 // These should be passed by pointer as they contain a lot of data.
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132 xQueue2 = xQueueCreate( 10, sizeof( struct AMessage * ) );
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135 // Queue was not created and must not be used.
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138 // ... Rest of task code.
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141 * \defgroup xQueueCreate xQueueCreate
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142 * \ingroup QueueManagement
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144 xQueueHandle xQueueCreate( unsigned portBASE_TYPE uxQueueLength, unsigned portBASE_TYPE uxItemSize );
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149 portBASE_TYPE xQueueSendToToFront(
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150 xQueueHandle xQueue,
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151 const void * pvItemToQueue,
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152 portTickType xTicksToWait
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156 * This is a macro that calls xQueueGenericSend().
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158 * Post an item to the front of a queue. The item is queued by copy, not by
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159 * reference. This function must not be called from an interrupt service
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160 * routine. See xQueueSendFromISR () for an alternative which may be used
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163 * @param xQueue The handle to the queue on which the item is to be posted.
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165 * @param pvItemToQueue A pointer to the item that is to be placed on the
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166 * queue. The size of the items the queue will hold was defined when the
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167 * queue was created, so this many bytes will be copied from pvItemToQueue
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168 * into the queue storage area.
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170 * @param xTicksToWait The maximum amount of time the task should block
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171 * waiting for space to become available on the queue, should it already
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172 * be full. The call will return immediately if this is set to 0 and the
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173 * queue is full. The time is defined in tick periods so the constant
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174 * portTICK_RATE_MS should be used to convert to real time if this is required.
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176 * @return pdTRUE if the item was successfully posted, otherwise errQUEUE_FULL.
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186 unsigned long ulVar = 10UL;
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188 void vATask( void *pvParameters )
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190 xQueueHandle xQueue1, xQueue2;
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191 struct AMessage *pxMessage;
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193 // Create a queue capable of containing 10 unsigned long values.
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194 xQueue1 = xQueueCreate( 10, sizeof( unsigned long ) );
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196 // Create a queue capable of containing 10 pointers to AMessage structures.
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197 // These should be passed by pointer as they contain a lot of data.
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198 xQueue2 = xQueueCreate( 10, sizeof( struct AMessage * ) );
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204 // Send an unsigned long. Wait for 10 ticks for space to become
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205 // available if necessary.
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206 if( xQueueSendToFront( xQueue1, ( void * ) &ulVar, ( portTickType ) 10 ) != pdPASS )
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208 // Failed to post the message, even after 10 ticks.
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214 // Send a pointer to a struct AMessage object. Don't block if the
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215 // queue is already full.
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216 pxMessage = & xMessage;
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217 xQueueSendToFront( xQueue2, ( void * ) &pxMessage, ( portTickType ) 0 );
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220 // ... Rest of task code.
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223 * \defgroup xQueueSend xQueueSend
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224 * \ingroup QueueManagement
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226 #define xQueueSendToFront( xQueue, pvItemToQueue, xTicksToWait ) xQueueGenericSend( ( xQueue ), ( pvItemToQueue ), ( xTicksToWait ), queueSEND_TO_FRONT )
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231 portBASE_TYPE xQueueSendToBack(
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232 xQueueHandle xQueue,
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233 const void * pvItemToQueue,
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234 portTickType xTicksToWait
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238 * This is a macro that calls xQueueGenericSend().
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240 * Post an item to the back of a queue. The item is queued by copy, not by
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241 * reference. This function must not be called from an interrupt service
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242 * routine. See xQueueSendFromISR () for an alternative which may be used
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245 * @param xQueue The handle to the queue on which the item is to be posted.
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247 * @param pvItemToQueue A pointer to the item that is to be placed on the
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248 * queue. The size of the items the queue will hold was defined when the
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249 * queue was created, so this many bytes will be copied from pvItemToQueue
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250 * into the queue storage area.
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252 * @param xTicksToWait The maximum amount of time the task should block
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253 * waiting for space to become available on the queue, should it already
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254 * be full. The call will return immediately if this is set to 0 and the queue
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255 * is full. The time is defined in tick periods so the constant
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256 * portTICK_RATE_MS should be used to convert to real time if this is required.
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258 * @return pdTRUE if the item was successfully posted, otherwise errQUEUE_FULL.
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268 unsigned long ulVar = 10UL;
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270 void vATask( void *pvParameters )
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272 xQueueHandle xQueue1, xQueue2;
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273 struct AMessage *pxMessage;
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275 // Create a queue capable of containing 10 unsigned long values.
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276 xQueue1 = xQueueCreate( 10, sizeof( unsigned long ) );
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278 // Create a queue capable of containing 10 pointers to AMessage structures.
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279 // These should be passed by pointer as they contain a lot of data.
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280 xQueue2 = xQueueCreate( 10, sizeof( struct AMessage * ) );
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286 // Send an unsigned long. Wait for 10 ticks for space to become
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287 // available if necessary.
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288 if( xQueueSendToBack( xQueue1, ( void * ) &ulVar, ( portTickType ) 10 ) != pdPASS )
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290 // Failed to post the message, even after 10 ticks.
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296 // Send a pointer to a struct AMessage object. Don't block if the
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297 // queue is already full.
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298 pxMessage = & xMessage;
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299 xQueueSendToBack( xQueue2, ( void * ) &pxMessage, ( portTickType ) 0 );
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302 // ... Rest of task code.
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305 * \defgroup xQueueSend xQueueSend
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306 * \ingroup QueueManagement
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308 #define xQueueSendToBack( xQueue, pvItemToQueue, xTicksToWait ) xQueueGenericSend( ( xQueue ), ( pvItemToQueue ), ( xTicksToWait ), queueSEND_TO_BACK )
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313 portBASE_TYPE xQueueSend(
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314 xQueueHandle xQueue,
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315 const void * pvItemToQueue,
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316 portTickType xTicksToWait
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320 * This is a macro that calls xQueueGenericSend(). It is included for
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321 * backward compatibility with versions of FreeRTOS.org that did not
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322 * include the xQueueSendToFront() and xQueueSendToBack() macros. It is
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323 * equivalent to xQueueSendToBack().
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325 * Post an item on a queue. The item is queued by copy, not by reference.
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326 * This function must not be called from an interrupt service routine.
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327 * See xQueueSendFromISR () for an alternative which may be used in an ISR.
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329 * @param xQueue The handle to the queue on which the item is to be posted.
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331 * @param pvItemToQueue A pointer to the item that is to be placed on the
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332 * queue. The size of the items the queue will hold was defined when the
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333 * queue was created, so this many bytes will be copied from pvItemToQueue
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334 * into the queue storage area.
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336 * @param xTicksToWait The maximum amount of time the task should block
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337 * waiting for space to become available on the queue, should it already
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338 * be full. The call will return immediately if this is set to 0 and the
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339 * queue is full. The time is defined in tick periods so the constant
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340 * portTICK_RATE_MS should be used to convert to real time if this is required.
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342 * @return pdTRUE if the item was successfully posted, otherwise errQUEUE_FULL.
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352 unsigned long ulVar = 10UL;
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354 void vATask( void *pvParameters )
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356 xQueueHandle xQueue1, xQueue2;
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357 struct AMessage *pxMessage;
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359 // Create a queue capable of containing 10 unsigned long values.
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360 xQueue1 = xQueueCreate( 10, sizeof( unsigned long ) );
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362 // Create a queue capable of containing 10 pointers to AMessage structures.
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363 // These should be passed by pointer as they contain a lot of data.
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364 xQueue2 = xQueueCreate( 10, sizeof( struct AMessage * ) );
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370 // Send an unsigned long. Wait for 10 ticks for space to become
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371 // available if necessary.
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372 if( xQueueSend( xQueue1, ( void * ) &ulVar, ( portTickType ) 10 ) != pdPASS )
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374 // Failed to post the message, even after 10 ticks.
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380 // Send a pointer to a struct AMessage object. Don't block if the
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381 // queue is already full.
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382 pxMessage = & xMessage;
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383 xQueueSend( xQueue2, ( void * ) &pxMessage, ( portTickType ) 0 );
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386 // ... Rest of task code.
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389 * \defgroup xQueueSend xQueueSend
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390 * \ingroup QueueManagement
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392 #define xQueueSend( xQueue, pvItemToQueue, xTicksToWait ) xQueueGenericSend( ( xQueue ), ( pvItemToQueue ), ( xTicksToWait ), queueSEND_TO_BACK )
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398 portBASE_TYPE xQueueGenericSend(
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399 xQueueHandle xQueue,
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400 const void * pvItemToQueue,
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401 portTickType xTicksToWait
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402 portBASE_TYPE xCopyPosition
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406 * It is preferred that the macros xQueueSend(), xQueueSendToFront() and
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407 * xQueueSendToBack() are used in place of calling this function directly.
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409 * Post an item on a queue. The item is queued by copy, not by reference.
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410 * This function must not be called from an interrupt service routine.
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411 * See xQueueSendFromISR () for an alternative which may be used in an ISR.
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413 * @param xQueue The handle to the queue on which the item is to be posted.
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415 * @param pvItemToQueue A pointer to the item that is to be placed on the
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416 * queue. The size of the items the queue will hold was defined when the
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417 * queue was created, so this many bytes will be copied from pvItemToQueue
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418 * into the queue storage area.
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420 * @param xTicksToWait The maximum amount of time the task should block
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421 * waiting for space to become available on the queue, should it already
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422 * be full. The call will return immediately if this is set to 0 and the
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423 * queue is full. The time is defined in tick periods so the constant
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424 * portTICK_RATE_MS should be used to convert to real time if this is required.
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426 * @param xCopyPosition Can take the value queueSEND_TO_BACK to place the
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427 * item at the back of the queue, or queueSEND_TO_FRONT to place the item
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428 * at the front of the queue (for high priority messages).
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430 * @return pdTRUE if the item was successfully posted, otherwise errQUEUE_FULL.
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440 unsigned long ulVar = 10UL;
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442 void vATask( void *pvParameters )
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444 xQueueHandle xQueue1, xQueue2;
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445 struct AMessage *pxMessage;
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447 // Create a queue capable of containing 10 unsigned long values.
\r
448 xQueue1 = xQueueCreate( 10, sizeof( unsigned long ) );
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450 // Create a queue capable of containing 10 pointers to AMessage structures.
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451 // These should be passed by pointer as they contain a lot of data.
\r
452 xQueue2 = xQueueCreate( 10, sizeof( struct AMessage * ) );
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458 // Send an unsigned long. Wait for 10 ticks for space to become
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459 // available if necessary.
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460 if( xQueueGenericSend( xQueue1, ( void * ) &ulVar, ( portTickType ) 10, queueSEND_TO_BACK ) != pdPASS )
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462 // Failed to post the message, even after 10 ticks.
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468 // Send a pointer to a struct AMessage object. Don't block if the
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469 // queue is already full.
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470 pxMessage = & xMessage;
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471 xQueueGenericSend( xQueue2, ( void * ) &pxMessage, ( portTickType ) 0, queueSEND_TO_BACK );
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474 // ... Rest of task code.
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477 * \defgroup xQueueSend xQueueSend
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478 * \ingroup QueueManagement
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480 signed portBASE_TYPE xQueueGenericSend( xQueueHandle pxQueue, const void * const pvItemToQueue, portTickType xTicksToWait, portBASE_TYPE xCopyPosition );
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485 portBASE_TYPE xQueuePeek(
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486 xQueueHandle xQueue,
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488 portTickType xTicksToWait
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491 * This is a macro that calls the xQueueGenericReceive() function.
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493 * Receive an item from a queue without removing the item from the queue.
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494 * The item is received by copy so a buffer of adequate size must be
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495 * provided. The number of bytes copied into the buffer was defined when
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496 * the queue was created.
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498 * Successfully received items remain on the queue so will be returned again
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499 * by the next call, or a call to xQueueReceive().
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501 * This macro must not be used in an interrupt service routine.
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503 * @param pxQueue The handle to the queue from which the item is to be
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506 * @param pvBuffer Pointer to the buffer into which the received item will
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509 * @param xTicksToWait The maximum amount of time the task should block
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510 * waiting for an item to receive should the queue be empty at the time
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511 * of the call. The time is defined in tick periods so the constant
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512 * portTICK_RATE_MS should be used to convert to real time if this is required.
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513 * xQueuePeek() will return immediately if xTicksToWait is 0 and the queue
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516 * @return pdTRUE if an item was successfully received from the queue,
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517 * otherwise pdFALSE.
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527 xQueueHandle xQueue;
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529 // Task to create a queue and post a value.
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530 void vATask( void *pvParameters )
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532 struct AMessage *pxMessage;
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534 // Create a queue capable of containing 10 pointers to AMessage structures.
\r
535 // These should be passed by pointer as they contain a lot of data.
\r
536 xQueue = xQueueCreate( 10, sizeof( struct AMessage * ) );
\r
539 // Failed to create the queue.
\r
544 // Send a pointer to a struct AMessage object. Don't block if the
\r
545 // queue is already full.
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546 pxMessage = & xMessage;
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547 xQueueSend( xQueue, ( void * ) &pxMessage, ( portTickType ) 0 );
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549 // ... Rest of task code.
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552 // Task to peek the data from the queue.
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553 void vADifferentTask( void *pvParameters )
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555 struct AMessage *pxRxedMessage;
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559 // Peek a message on the created queue. Block for 10 ticks if a
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560 // message is not immediately available.
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561 if( xQueuePeek( xQueue, &( pxRxedMessage ), ( portTickType ) 10 ) )
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563 // pcRxedMessage now points to the struct AMessage variable posted
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564 // by vATask, but the item still remains on the queue.
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568 // ... Rest of task code.
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571 * \defgroup xQueueReceive xQueueReceive
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572 * \ingroup QueueManagement
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574 #define xQueuePeek( xQueue, pvBuffer, xTicksToWait ) xQueueGenericReceive( ( xQueue ), ( pvBuffer ), ( xTicksToWait ), pdTRUE )
\r
579 portBASE_TYPE xQueueReceive(
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580 xQueueHandle xQueue,
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582 portTickType xTicksToWait
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585 * This is a macro that calls the xQueueGenericReceive() function.
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587 * Receive an item from a queue. The item is received by copy so a buffer of
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588 * adequate size must be provided. The number of bytes copied into the buffer
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589 * was defined when the queue was created.
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591 * Successfully received items are removed from the queue.
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593 * This function must not be used in an interrupt service routine. See
\r
594 * xQueueReceiveFromISR for an alternative that can.
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596 * @param pxQueue The handle to the queue from which the item is to be
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599 * @param pvBuffer Pointer to the buffer into which the received item will
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602 * @param xTicksToWait The maximum amount of time the task should block
\r
603 * waiting for an item to receive should the queue be empty at the time
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604 * of the call. xQueueReceive() will return immediately if xTicksToWait
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605 * is zero and the queue is empty. The time is defined in tick periods so the
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606 * constant portTICK_RATE_MS should be used to convert to real time if this is
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609 * @return pdTRUE if an item was successfully received from the queue,
\r
610 * otherwise pdFALSE.
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620 xQueueHandle xQueue;
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622 // Task to create a queue and post a value.
\r
623 void vATask( void *pvParameters )
\r
625 struct AMessage *pxMessage;
\r
627 // Create a queue capable of containing 10 pointers to AMessage structures.
\r
628 // These should be passed by pointer as they contain a lot of data.
\r
629 xQueue = xQueueCreate( 10, sizeof( struct AMessage * ) );
\r
632 // Failed to create the queue.
\r
637 // Send a pointer to a struct AMessage object. Don't block if the
\r
638 // queue is already full.
\r
639 pxMessage = & xMessage;
\r
640 xQueueSend( xQueue, ( void * ) &pxMessage, ( portTickType ) 0 );
\r
642 // ... Rest of task code.
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645 // Task to receive from the queue.
\r
646 void vADifferentTask( void *pvParameters )
\r
648 struct AMessage *pxRxedMessage;
\r
652 // Receive a message on the created queue. Block for 10 ticks if a
\r
653 // message is not immediately available.
\r
654 if( xQueueReceive( xQueue, &( pxRxedMessage ), ( portTickType ) 10 ) )
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656 // pcRxedMessage now points to the struct AMessage variable posted
\r
661 // ... Rest of task code.
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664 * \defgroup xQueueReceive xQueueReceive
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665 * \ingroup QueueManagement
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667 #define xQueueReceive( xQueue, pvBuffer, xTicksToWait ) xQueueGenericReceive( ( xQueue ), ( pvBuffer ), ( xTicksToWait ), pdFALSE )
\r
673 portBASE_TYPE xQueueGenericReceive(
\r
674 xQueueHandle xQueue,
\r
676 portTickType xTicksToWait
\r
677 portBASE_TYPE xJustPeek
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680 * It is preferred that the macro xQueueReceive() be used rather than calling
\r
681 * this function directly.
\r
683 * Receive an item from a queue. The item is received by copy so a buffer of
\r
684 * adequate size must be provided. The number of bytes copied into the buffer
\r
685 * was defined when the queue was created.
\r
687 * This function must not be used in an interrupt service routine. See
\r
688 * xQueueReceiveFromISR for an alternative that can.
\r
690 * @param pxQueue The handle to the queue from which the item is to be
\r
693 * @param pvBuffer Pointer to the buffer into which the received item will
\r
696 * @param xTicksToWait The maximum amount of time the task should block
\r
697 * waiting for an item to receive should the queue be empty at the time
\r
698 * of the call. The time is defined in tick periods so the constant
\r
699 * portTICK_RATE_MS should be used to convert to real time if this is required.
\r
700 * xQueueGenericReceive() will return immediately if the queue is empty and
\r
701 * xTicksToWait is 0.
\r
703 * @param xJustPeek When set to true, the item received from the queue is not
\r
704 * actually removed from the queue - meaning a subsequent call to
\r
705 * xQueueReceive() will return the same item. When set to false, the item
\r
706 * being received from the queue is also removed from the queue.
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708 * @return pdTRUE if an item was successfully received from the queue,
\r
709 * otherwise pdFALSE.
\r
719 xQueueHandle xQueue;
\r
721 // Task to create a queue and post a value.
\r
722 void vATask( void *pvParameters )
\r
724 struct AMessage *pxMessage;
\r
726 // Create a queue capable of containing 10 pointers to AMessage structures.
\r
727 // These should be passed by pointer as they contain a lot of data.
\r
728 xQueue = xQueueCreate( 10, sizeof( struct AMessage * ) );
\r
731 // Failed to create the queue.
\r
736 // Send a pointer to a struct AMessage object. Don't block if the
\r
737 // queue is already full.
\r
738 pxMessage = & xMessage;
\r
739 xQueueSend( xQueue, ( void * ) &pxMessage, ( portTickType ) 0 );
\r
741 // ... Rest of task code.
\r
744 // Task to receive from the queue.
\r
745 void vADifferentTask( void *pvParameters )
\r
747 struct AMessage *pxRxedMessage;
\r
751 // Receive a message on the created queue. Block for 10 ticks if a
\r
752 // message is not immediately available.
\r
753 if( xQueueGenericReceive( xQueue, &( pxRxedMessage ), ( portTickType ) 10 ) )
\r
755 // pcRxedMessage now points to the struct AMessage variable posted
\r
760 // ... Rest of task code.
\r
763 * \defgroup xQueueReceive xQueueReceive
\r
764 * \ingroup QueueManagement
\r
766 signed portBASE_TYPE xQueueGenericReceive( xQueueHandle xQueue, void * const pvBuffer, portTickType xTicksToWait, portBASE_TYPE xJustPeek );
\r
770 * <pre>unsigned portBASE_TYPE uxQueueMessagesWaiting( const xQueueHandle xQueue );</pre>
\r
772 * Return the number of messages stored in a queue.
\r
774 * @param xQueue A handle to the queue being queried.
\r
776 * @return The number of messages available in the queue.
\r
778 * \page uxQueueMessagesWaiting uxQueueMessagesWaiting
\r
779 * \ingroup QueueManagement
\r
781 unsigned portBASE_TYPE uxQueueMessagesWaiting( const xQueueHandle xQueue );
\r
785 * <pre>void vQueueDelete( xQueueHandle xQueue );</pre>
\r
787 * Delete a queue - freeing all the memory allocated for storing of items
\r
788 * placed on the queue.
\r
790 * @param xQueue A handle to the queue to be deleted.
\r
792 * \page vQueueDelete vQueueDelete
\r
793 * \ingroup QueueManagement
\r
795 void vQueueDelete( xQueueHandle pxQueue );
\r
800 portBASE_TYPE xQueueSendToFrontFromISR(
\r
801 xQueueHandle pxQueue,
\r
802 const void *pvItemToQueue,
\r
803 portBASE_TYPE *pxHigherPriorityTaskWoken
\r
807 * This is a macro that calls xQueueGenericSendFromISR().
\r
809 * Post an item to the front of a queue. It is safe to use this macro from
\r
810 * within an interrupt service routine.
\r
812 * Items are queued by copy not reference so it is preferable to only
\r
813 * queue small items, especially when called from an ISR. In most cases
\r
814 * it would be preferable to store a pointer to the item being queued.
\r
816 * @param xQueue The handle to the queue on which the item is to be posted.
\r
818 * @param pvItemToQueue A pointer to the item that is to be placed on the
\r
819 * queue. The size of the items the queue will hold was defined when the
\r
820 * queue was created, so this many bytes will be copied from pvItemToQueue
\r
821 * into the queue storage area.
\r
823 * @param pxHigherPriorityTaskWoken xQueueSendToFrontFromISR() will set
\r
824 * *pxHigherPriorityTaskWoken to pdTRUE if sending to the queue caused a task
\r
825 * to unblock, and the unblocked task has a priority higher than the currently
\r
826 * running task. If xQueueSendToFromFromISR() sets this value to pdTRUE then
\r
827 * a context switch should be requested before the interrupt is exited.
\r
829 * @return pdTRUE if the data was successfully sent to the queue, otherwise
\r
832 * Example usage for buffered IO (where the ISR can obtain more than one value
\r
835 void vBufferISR( void )
\r
838 portBASE_TYPE xHigherPrioritTaskWoken;
\r
840 // We have not woken a task at the start of the ISR.
\r
841 xHigherPriorityTaskWoken = pdFALSE;
\r
843 // Loop until the buffer is empty.
\r
846 // Obtain a byte from the buffer.
\r
847 cIn = portINPUT_BYTE( RX_REGISTER_ADDRESS );
\r
850 xQueueSendToFrontFromISR( xRxQueue, &cIn, &xHigherPriorityTaskWoken );
\r
852 } while( portINPUT_BYTE( BUFFER_COUNT ) );
\r
854 // Now the buffer is empty we can switch context if necessary.
\r
855 if( xHigherPriorityTaskWoken )
\r
862 * \defgroup xQueueSendFromISR xQueueSendFromISR
\r
863 * \ingroup QueueManagement
\r
865 #define xQueueSendToFrontFromISR( pxQueue, pvItemToQueue, pxHigherPriorityTaskWoken ) xQueueGenericSendFromISR( ( pxQueue ), ( pvItemToQueue ), ( pxHigherPriorityTaskWoken ), queueSEND_TO_FRONT )
\r
871 portBASE_TYPE xQueueSendToBackFromISR(
\r
872 xQueueHandle pxQueue,
\r
873 const void *pvItemToQueue,
\r
874 portBASE_TYPE *pxHigherPriorityTaskWoken
\r
878 * This is a macro that calls xQueueGenericSendFromISR().
\r
880 * Post an item to the back of a queue. It is safe to use this macro from
\r
881 * within an interrupt service routine.
\r
883 * Items are queued by copy not reference so it is preferable to only
\r
884 * queue small items, especially when called from an ISR. In most cases
\r
885 * it would be preferable to store a pointer to the item being queued.
\r
887 * @param xQueue The handle to the queue on which the item is to be posted.
\r
889 * @param pvItemToQueue A pointer to the item that is to be placed on the
\r
890 * queue. The size of the items the queue will hold was defined when the
\r
891 * queue was created, so this many bytes will be copied from pvItemToQueue
\r
892 * into the queue storage area.
\r
894 * @param pxHigherPriorityTaskWoken xQueueSendToBackFromISR() will set
\r
895 * *pxHigherPriorityTaskWoken to pdTRUE if sending to the queue caused a task
\r
896 * to unblock, and the unblocked task has a priority higher than the currently
\r
897 * running task. If xQueueSendToBackFromISR() sets this value to pdTRUE then
\r
898 * a context switch should be requested before the interrupt is exited.
\r
900 * @return pdTRUE if the data was successfully sent to the queue, otherwise
\r
903 * Example usage for buffered IO (where the ISR can obtain more than one value
\r
906 void vBufferISR( void )
\r
909 portBASE_TYPE xHigherPriorityTaskWoken;
\r
911 // We have not woken a task at the start of the ISR.
\r
912 xHigherPriorityTaskWoken = pdFALSE;
\r
914 // Loop until the buffer is empty.
\r
917 // Obtain a byte from the buffer.
\r
918 cIn = portINPUT_BYTE( RX_REGISTER_ADDRESS );
\r
921 xQueueSendToBackFromISR( xRxQueue, &cIn, &xHigherPriorityTaskWoken );
\r
923 } while( portINPUT_BYTE( BUFFER_COUNT ) );
\r
925 // Now the buffer is empty we can switch context if necessary.
\r
926 if( xHigherPriorityTaskWoken )
\r
933 * \defgroup xQueueSendFromISR xQueueSendFromISR
\r
934 * \ingroup QueueManagement
\r
936 #define xQueueSendToBackFromISR( pxQueue, pvItemToQueue, pxHigherPriorityTaskWoken ) xQueueGenericSendFromISR( ( pxQueue ), ( pvItemToQueue ), ( pxHigherPriorityTaskWoken ), queueSEND_TO_BACK )
\r
941 portBASE_TYPE xQueueSendFromISR(
\r
942 xQueueHandle pxQueue,
\r
943 const void *pvItemToQueue,
\r
944 portBASE_TYPE *pxHigherPriorityTaskWoken
\r
948 * This is a macro that calls xQueueGenericSendFromISR(). It is included
\r
949 * for backward compatibility with versions of FreeRTOS.org that did not
\r
950 * include the xQueueSendToBackFromISR() and xQueueSendToFrontFromISR()
\r
953 * Post an item to the back of a queue. It is safe to use this function from
\r
954 * within an interrupt service routine.
\r
956 * Items are queued by copy not reference so it is preferable to only
\r
957 * queue small items, especially when called from an ISR. In most cases
\r
958 * it would be preferable to store a pointer to the item being queued.
\r
960 * @param xQueue The handle to the queue on which the item is to be posted.
\r
962 * @param pvItemToQueue A pointer to the item that is to be placed on the
\r
963 * queue. The size of the items the queue will hold was defined when the
\r
964 * queue was created, so this many bytes will be copied from pvItemToQueue
\r
965 * into the queue storage area.
\r
967 * @param pxHigherPriorityTaskWoken xQueueSendFromISR() will set
\r
968 * *pxHigherPriorityTaskWoken to pdTRUE if sending to the queue caused a task
\r
969 * to unblock, and the unblocked task has a priority higher than the currently
\r
970 * running task. If xQueueSendFromISR() sets this value to pdTRUE then
\r
971 * a context switch should be requested before the interrupt is exited.
\r
973 * @return pdTRUE if the data was successfully sent to the queue, otherwise
\r
976 * Example usage for buffered IO (where the ISR can obtain more than one value
\r
979 void vBufferISR( void )
\r
982 portBASE_TYPE xHigherPriorityTaskWoken;
\r
984 // We have not woken a task at the start of the ISR.
\r
985 xHigherPriorityTaskWoken = pdFALSE;
\r
987 // Loop until the buffer is empty.
\r
990 // Obtain a byte from the buffer.
\r
991 cIn = portINPUT_BYTE( RX_REGISTER_ADDRESS );
\r
994 xQueueSendFromISR( xRxQueue, &cIn, &xHigherPriorityTaskWoken );
\r
996 } while( portINPUT_BYTE( BUFFER_COUNT ) );
\r
998 // Now the buffer is empty we can switch context if necessary.
\r
999 if( xHigherPriorityTaskWoken )
\r
1001 // Actual macro used here is port specific.
\r
1002 taskYIELD_FROM_ISR ();
\r
1007 * \defgroup xQueueSendFromISR xQueueSendFromISR
\r
1008 * \ingroup QueueManagement
\r
1010 #define xQueueSendFromISR( pxQueue, pvItemToQueue, pxHigherPriorityTaskWoken ) xQueueGenericSendFromISR( ( pxQueue ), ( pvItemToQueue ), ( pxHigherPriorityTaskWoken ), queueSEND_TO_BACK )
\r
1015 portBASE_TYPE xQueueGenericSendFromISR(
\r
1016 xQueueHandle pxQueue,
\r
1017 const void *pvItemToQueue,
\r
1018 portBASE_TYPE *pxHigherPriorityTaskWoken,
\r
1019 portBASE_TYPE xCopyPosition
\r
1023 * It is preferred that the macros xQueueSendFromISR(),
\r
1024 * xQueueSendToFrontFromISR() and xQueueSendToBackFromISR() be used in place
\r
1025 * of calling this function directly.
\r
1027 * Post an item on a queue. It is safe to use this function from within an
\r
1028 * interrupt service routine.
\r
1030 * Items are queued by copy not reference so it is preferable to only
\r
1031 * queue small items, especially when called from an ISR. In most cases
\r
1032 * it would be preferable to store a pointer to the item being queued.
\r
1034 * @param xQueue The handle to the queue on which the item is to be posted.
\r
1036 * @param pvItemToQueue A pointer to the item that is to be placed on the
\r
1037 * queue. The size of the items the queue will hold was defined when the
\r
1038 * queue was created, so this many bytes will be copied from pvItemToQueue
\r
1039 * into the queue storage area.
\r
1041 * @param pxHigherPriorityTaskWoken xQueueGenericSendFromISR() will set
\r
1042 * *pxHigherPriorityTaskWoken to pdTRUE if sending to the queue caused a task
\r
1043 * to unblock, and the unblocked task has a priority higher than the currently
\r
1044 * running task. If xQueueGenericSendFromISR() sets this value to pdTRUE then
\r
1045 * a context switch should be requested before the interrupt is exited.
\r
1047 * @param xCopyPosition Can take the value queueSEND_TO_BACK to place the
\r
1048 * item at the back of the queue, or queueSEND_TO_FRONT to place the item
\r
1049 * at the front of the queue (for high priority messages).
\r
1051 * @return pdTRUE if the data was successfully sent to the queue, otherwise
\r
1054 * Example usage for buffered IO (where the ISR can obtain more than one value
\r
1057 void vBufferISR( void )
\r
1060 portBASE_TYPE xHigherPriorityTaskWokenByPost;
\r
1062 // We have not woken a task at the start of the ISR.
\r
1063 xHigherPriorityTaskWokenByPost = pdFALSE;
\r
1065 // Loop until the buffer is empty.
\r
1068 // Obtain a byte from the buffer.
\r
1069 cIn = portINPUT_BYTE( RX_REGISTER_ADDRESS );
\r
1071 // Post each byte.
\r
1072 xQueueGenericSendFromISR( xRxQueue, &cIn, &xHigherPriorityTaskWokenByPost, queueSEND_TO_BACK );
\r
1074 } while( portINPUT_BYTE( BUFFER_COUNT ) );
\r
1076 // Now the buffer is empty we can switch context if necessary. Note that the
\r
1077 // name of the yield function required is port specific.
\r
1078 if( xHigherPriorityTaskWokenByPost )
\r
1080 taskYIELD_YIELD_FROM_ISR();
\r
1085 * \defgroup xQueueSendFromISR xQueueSendFromISR
\r
1086 * \ingroup QueueManagement
\r
1088 signed portBASE_TYPE xQueueGenericSendFromISR( xQueueHandle pxQueue, const void * const pvItemToQueue, signed portBASE_TYPE *pxHigherPriorityTaskWoken, portBASE_TYPE xCopyPosition );
\r
1093 portBASE_TYPE xQueueReceiveFromISR(
\r
1094 xQueueHandle pxQueue,
\r
1096 portBASE_TYPE *pxTaskWoken
\r
1100 * Receive an item from a queue. It is safe to use this function from within an
\r
1101 * interrupt service routine.
\r
1103 * @param pxQueue The handle to the queue from which the item is to be
\r
1106 * @param pvBuffer Pointer to the buffer into which the received item will
\r
1109 * @param pxTaskWoken A task may be blocked waiting for space to become
\r
1110 * available on the queue. If xQueueReceiveFromISR causes such a task to
\r
1111 * unblock *pxTaskWoken will get set to pdTRUE, otherwise *pxTaskWoken will
\r
1112 * remain unchanged.
\r
1114 * @return pdTRUE if an item was successfully received from the queue,
\r
1115 * otherwise pdFALSE.
\r
1120 xQueueHandle xQueue;
\r
1122 // Function to create a queue and post some values.
\r
1123 void vAFunction( void *pvParameters )
\r
1125 char cValueToPost;
\r
1126 const portTickType xBlockTime = ( portTickType )0xff;
\r
1128 // Create a queue capable of containing 10 characters.
\r
1129 xQueue = xQueueCreate( 10, sizeof( char ) );
\r
1132 // Failed to create the queue.
\r
1137 // Post some characters that will be used within an ISR. If the queue
\r
1138 // is full then this task will block for xBlockTime ticks.
\r
1139 cValueToPost = 'a';
\r
1140 xQueueSend( xQueue, ( void * ) &cValueToPost, xBlockTime );
\r
1141 cValueToPost = 'b';
\r
1142 xQueueSend( xQueue, ( void * ) &cValueToPost, xBlockTime );
\r
1144 // ... keep posting characters ... this task may block when the queue
\r
1147 cValueToPost = 'c';
\r
1148 xQueueSend( xQueue, ( void * ) &cValueToPost, xBlockTime );
\r
1151 // ISR that outputs all the characters received on the queue.
\r
1152 void vISR_Routine( void )
\r
1154 portBASE_TYPE xTaskWokenByReceive = pdFALSE;
\r
1157 while( xQueueReceiveFromISR( xQueue, ( void * ) &cRxedChar, &xTaskWokenByReceive) )
\r
1159 // A character was received. Output the character now.
\r
1160 vOutputCharacter( cRxedChar );
\r
1162 // If removing the character from the queue woke the task that was
\r
1163 // posting onto the queue cTaskWokenByReceive will have been set to
\r
1164 // pdTRUE. No matter how many times this loop iterates only one
\r
1165 // task will be woken.
\r
1168 if( cTaskWokenByPost != ( char ) pdFALSE;
\r
1174 * \defgroup xQueueReceiveFromISR xQueueReceiveFromISR
\r
1175 * \ingroup QueueManagement
\r
1177 signed portBASE_TYPE xQueueReceiveFromISR( xQueueHandle pxQueue, void * const pvBuffer, signed portBASE_TYPE *pxTaskWoken );
\r
1180 * Utilities to query queue that are safe to use from an ISR. These utilities
\r
1181 * should be used only from witin an ISR, or within a critical section.
\r
1183 signed portBASE_TYPE xQueueIsQueueEmptyFromISR( const xQueueHandle pxQueue );
\r
1184 signed portBASE_TYPE xQueueIsQueueFullFromISR( const xQueueHandle pxQueue );
\r
1185 unsigned portBASE_TYPE uxQueueMessagesWaitingFromISR( const xQueueHandle pxQueue );
\r
1189 * xQueueAltGenericSend() is an alternative version of xQueueGenericSend().
\r
1190 * Likewise xQueueAltGenericReceive() is an alternative version of
\r
1191 * xQueueGenericReceive().
\r
1193 * The source code that implements the alternative (Alt) API is much
\r
1194 * simpler because it executes everything from within a critical section.
\r
1195 * This is the approach taken by many other RTOSes, but FreeRTOS.org has the
\r
1196 * preferred fully featured API too. The fully featured API has more
\r
1197 * complex code that takes longer to execute, but makes much less use of
\r
1198 * critical sections. Therefore the alternative API sacrifices interrupt
\r
1199 * responsiveness to gain execution speed, whereas the fully featured API
\r
1200 * sacrifices execution speed to ensure better interrupt responsiveness.
\r
1202 signed portBASE_TYPE xQueueAltGenericSend( xQueueHandle pxQueue, const void * const pvItemToQueue, portTickType xTicksToWait, portBASE_TYPE xCopyPosition );
\r
1203 signed portBASE_TYPE xQueueAltGenericReceive( xQueueHandle pxQueue, void * const pvBuffer, portTickType xTicksToWait, portBASE_TYPE xJustPeeking );
\r
1204 #define xQueueAltSendToFront( xQueue, pvItemToQueue, xTicksToWait ) xQueueAltGenericSend( ( xQueue ), ( pvItemToQueue ), ( xTicksToWait ), queueSEND_TO_FRONT )
\r
1205 #define xQueueAltSendToBack( xQueue, pvItemToQueue, xTicksToWait ) xQueueAltGenericSend( ( xQueue ), ( pvItemToQueue ), ( xTicksToWait ), queueSEND_TO_BACK )
\r
1206 #define xQueueAltReceive( xQueue, pvBuffer, xTicksToWait ) xQueueAltGenericReceive( ( xQueue ), ( pvBuffer ), ( xTicksToWait ), pdFALSE )
\r
1207 #define xQueueAltPeek( xQueue, pvBuffer, xTicksToWait ) xQueueAltGenericReceive( ( xQueue ), ( pvBuffer ), ( xTicksToWait ), pdTRUE )
\r
1210 * The functions defined above are for passing data to and from tasks. The
\r
1211 * functions below are the equivalents for passing data to and from
\r
1214 * These functions are called from the co-routine macro implementation and
\r
1215 * should not be called directly from application code. Instead use the macro
\r
1216 * wrappers defined within croutine.h.
\r
1218 signed portBASE_TYPE xQueueCRSendFromISR( xQueueHandle pxQueue, const void *pvItemToQueue, signed portBASE_TYPE xCoRoutinePreviouslyWoken );
\r
1219 signed portBASE_TYPE xQueueCRReceiveFromISR( xQueueHandle pxQueue, void *pvBuffer, signed portBASE_TYPE *pxTaskWoken );
\r
1220 signed portBASE_TYPE xQueueCRSend( xQueueHandle pxQueue, const void *pvItemToQueue, portTickType xTicksToWait );
\r
1221 signed portBASE_TYPE xQueueCRReceive( xQueueHandle pxQueue, void *pvBuffer, portTickType xTicksToWait );
\r
1224 * For internal use only. Use xSemaphoreCreateMutex() or
\r
1225 * xSemaphoreCreateCounting() instead of calling these functions directly.
\r
1227 xQueueHandle xQueueCreateMutex( void );
\r
1228 xQueueHandle xQueueCreateCountingSemaphore( unsigned portBASE_TYPE uxCountValue, unsigned portBASE_TYPE uxInitialCount );
\r
1231 * For internal use only. Use xSemaphoreTakeMutexRecursive() or
\r
1232 * xSemaphoreGiveMutexRecursive() instead of calling these functions directly.
\r
1234 portBASE_TYPE xQueueTakeMutexRecursive( xQueueHandle pxMutex, portTickType xBlockTime );
\r
1235 portBASE_TYPE xQueueGiveMutexRecursive( xQueueHandle pxMutex );
\r
1238 * The registry is provided as a means for kernel aware debuggers to
\r
1239 * locate queues, semaphores and mutexes. Call vQueueAddToRegistry() add
\r
1240 * a queue, semaphore or mutex handle to the registry if you want the handle
\r
1241 * to be available to a kernel aware debugger. If you are not using a kernel
\r
1242 * aware debugger then this function can be ignored.
\r
1244 * configQUEUE_REGISTRY_SIZE defines the maximum number of handles the
\r
1245 * registry can hold. configQUEUE_REGISTRY_SIZE must be greater than 0
\r
1246 * within FreeRTOSConfig.h for the registry to be available. Its value
\r
1247 * does not effect the number of queues, semaphores and mutexes that can be
\r
1248 * created - just the number that the registry can hold.
\r
1250 * @param xQueue The handle of the queue being added to the registry. This
\r
1251 * is the handle returned by a call to xQueueCreate(). Semaphore and mutex
\r
1252 * handles can also be passed in here.
\r
1254 * @param pcName The name to be associated with the handle. This is the
\r
1255 * name that the kernel aware debugger will display.
\r
1257 #if configQUEUE_REGISTRY_SIZE > 0U
\r
1258 void vQueueAddToRegistry( xQueueHandle xQueue, signed char *pcName );
\r
1261 /* Not a public API function, hence the 'Restricted' in the name. */
\r
1262 void vQueueWaitForMessageRestricted( xQueueHandle pxQueue, portTickType xTicksToWait );
\r
1265 #ifdef __cplusplus
\r
1269 #endif /* QUEUE_H */
\r
projects / freertos / blob