Update revision to use TI's mqtt and Freertos.

Dependencies:   mbed client server

Fork of cc3100_Test_mqtt_CM3 by David Fletcher

Committer:
dflet
Date:
Thu Sep 03 14:02:37 2015 +0000
Revision:
3:a8c249046181
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dflet 3:a8c249046181 1 /*
dflet 3:a8c249046181 2 FreeRTOS V8.2.1 - Copyright (C) 2015 Real Time Engineers Ltd.
dflet 3:a8c249046181 3 All rights reserved
dflet 3:a8c249046181 4
dflet 3:a8c249046181 5 VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
dflet 3:a8c249046181 6
dflet 3:a8c249046181 7 This file is part of the FreeRTOS distribution.
dflet 3:a8c249046181 8
dflet 3:a8c249046181 9 FreeRTOS is free software; you can redistribute it and/or modify it under
dflet 3:a8c249046181 10 the terms of the GNU General Public License (version 2) as published by the
dflet 3:a8c249046181 11 Free Software Foundation >>!AND MODIFIED BY!<< the FreeRTOS exception.
dflet 3:a8c249046181 12
dflet 3:a8c249046181 13 ***************************************************************************
dflet 3:a8c249046181 14 >>! NOTE: The modification to the GPL is included to allow you to !<<
dflet 3:a8c249046181 15 >>! distribute a combined work that includes FreeRTOS without being !<<
dflet 3:a8c249046181 16 >>! obliged to provide the source code for proprietary components !<<
dflet 3:a8c249046181 17 >>! outside of the FreeRTOS kernel. !<<
dflet 3:a8c249046181 18 ***************************************************************************
dflet 3:a8c249046181 19
dflet 3:a8c249046181 20 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
dflet 3:a8c249046181 21 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
dflet 3:a8c249046181 22 FOR A PARTICULAR PURPOSE. Full license text is available on the following
dflet 3:a8c249046181 23 link: http://www.freertos.org/a00114.html
dflet 3:a8c249046181 24
dflet 3:a8c249046181 25 ***************************************************************************
dflet 3:a8c249046181 26 * *
dflet 3:a8c249046181 27 * FreeRTOS provides completely free yet professionally developed, *
dflet 3:a8c249046181 28 * robust, strictly quality controlled, supported, and cross *
dflet 3:a8c249046181 29 * platform software that is more than just the market leader, it *
dflet 3:a8c249046181 30 * is the industry's de facto standard. *
dflet 3:a8c249046181 31 * *
dflet 3:a8c249046181 32 * Help yourself get started quickly while simultaneously helping *
dflet 3:a8c249046181 33 * to support the FreeRTOS project by purchasing a FreeRTOS *
dflet 3:a8c249046181 34 * tutorial book, reference manual, or both: *
dflet 3:a8c249046181 35 * http://www.FreeRTOS.org/Documentation *
dflet 3:a8c249046181 36 * *
dflet 3:a8c249046181 37 ***************************************************************************
dflet 3:a8c249046181 38
dflet 3:a8c249046181 39 http://www.FreeRTOS.org/FAQHelp.html - Having a problem? Start by reading
dflet 3:a8c249046181 40 the FAQ page "My application does not run, what could be wrong?". Have you
dflet 3:a8c249046181 41 defined configASSERT()?
dflet 3:a8c249046181 42
dflet 3:a8c249046181 43 http://www.FreeRTOS.org/support - In return for receiving this top quality
dflet 3:a8c249046181 44 embedded software for free we request you assist our global community by
dflet 3:a8c249046181 45 participating in the support forum.
dflet 3:a8c249046181 46
dflet 3:a8c249046181 47 http://www.FreeRTOS.org/training - Investing in training allows your team to
dflet 3:a8c249046181 48 be as productive as possible as early as possible. Now you can receive
dflet 3:a8c249046181 49 FreeRTOS training directly from Richard Barry, CEO of Real Time Engineers
dflet 3:a8c249046181 50 Ltd, and the world's leading authority on the world's leading RTOS.
dflet 3:a8c249046181 51
dflet 3:a8c249046181 52 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
dflet 3:a8c249046181 53 including FreeRTOS+Trace - an indispensable productivity tool, a DOS
dflet 3:a8c249046181 54 compatible FAT file system, and our tiny thread aware UDP/IP stack.
dflet 3:a8c249046181 55
dflet 3:a8c249046181 56 http://www.FreeRTOS.org/labs - Where new FreeRTOS products go to incubate.
dflet 3:a8c249046181 57 Come and try FreeRTOS+TCP, our new open source TCP/IP stack for FreeRTOS.
dflet 3:a8c249046181 58
dflet 3:a8c249046181 59 http://www.OpenRTOS.com - Real Time Engineers ltd. license FreeRTOS to High
dflet 3:a8c249046181 60 Integrity Systems ltd. to sell under the OpenRTOS brand. Low cost OpenRTOS
dflet 3:a8c249046181 61 licenses offer ticketed support, indemnification and commercial middleware.
dflet 3:a8c249046181 62
dflet 3:a8c249046181 63 http://www.SafeRTOS.com - High Integrity Systems also provide a safety
dflet 3:a8c249046181 64 engineered and independently SIL3 certified version for use in safety and
dflet 3:a8c249046181 65 mission critical applications that require provable dependability.
dflet 3:a8c249046181 66
dflet 3:a8c249046181 67 1 tab == 4 spaces!
dflet 3:a8c249046181 68 */
dflet 3:a8c249046181 69
dflet 3:a8c249046181 70 #ifndef SEMAPHORE_H
dflet 3:a8c249046181 71 #define SEMAPHORE_H
dflet 3:a8c249046181 72
dflet 3:a8c249046181 73 #ifndef INC_FREERTOS_H
dflet 3:a8c249046181 74 #error "include FreeRTOS.h" must appear in source files before "include semphr.h"
dflet 3:a8c249046181 75 #endif
dflet 3:a8c249046181 76
dflet 3:a8c249046181 77 #include "queue.h"
dflet 3:a8c249046181 78
dflet 3:a8c249046181 79 typedef QueueHandle_t SemaphoreHandle_t;
dflet 3:a8c249046181 80
dflet 3:a8c249046181 81 #define semBINARY_SEMAPHORE_QUEUE_LENGTH ( ( uint8_t ) 1U )
dflet 3:a8c249046181 82 #define semSEMAPHORE_QUEUE_ITEM_LENGTH ( ( uint8_t ) 0U )
dflet 3:a8c249046181 83 #define semGIVE_BLOCK_TIME ( ( TickType_t ) 0U )
dflet 3:a8c249046181 84
dflet 3:a8c249046181 85
dflet 3:a8c249046181 86 /**
dflet 3:a8c249046181 87 * semphr. h
dflet 3:a8c249046181 88 * <pre>vSemaphoreCreateBinary( SemaphoreHandle_t xSemaphore )</pre>
dflet 3:a8c249046181 89 *
dflet 3:a8c249046181 90 * This old vSemaphoreCreateBinary() macro is now deprecated in favour of the
dflet 3:a8c249046181 91 * xSemaphoreCreateBinary() function. Note that binary semaphores created using
dflet 3:a8c249046181 92 * the vSemaphoreCreateBinary() macro are created in a state such that the
dflet 3:a8c249046181 93 * first call to 'take' the semaphore would pass, whereas binary semaphores
dflet 3:a8c249046181 94 * created using xSemaphoreCreateBinary() are created in a state such that the
dflet 3:a8c249046181 95 * the semaphore must first be 'given' before it can be 'taken'.
dflet 3:a8c249046181 96 *
dflet 3:a8c249046181 97 * <i>Macro</i> that implements a semaphore by using the existing queue mechanism.
dflet 3:a8c249046181 98 * The queue length is 1 as this is a binary semaphore. The data size is 0
dflet 3:a8c249046181 99 * as we don't want to actually store any data - we just want to know if the
dflet 3:a8c249046181 100 * queue is empty or full.
dflet 3:a8c249046181 101 *
dflet 3:a8c249046181 102 * This type of semaphore can be used for pure synchronisation between tasks or
dflet 3:a8c249046181 103 * between an interrupt and a task. The semaphore need not be given back once
dflet 3:a8c249046181 104 * obtained, so one task/interrupt can continuously 'give' the semaphore while
dflet 3:a8c249046181 105 * another continuously 'takes' the semaphore. For this reason this type of
dflet 3:a8c249046181 106 * semaphore does not use a priority inheritance mechanism. For an alternative
dflet 3:a8c249046181 107 * that does use priority inheritance see xSemaphoreCreateMutex().
dflet 3:a8c249046181 108 *
dflet 3:a8c249046181 109 * @param xSemaphore Handle to the created semaphore. Should be of type SemaphoreHandle_t.
dflet 3:a8c249046181 110 *
dflet 3:a8c249046181 111 * Example usage:
dflet 3:a8c249046181 112 <pre>
dflet 3:a8c249046181 113 SemaphoreHandle_t xSemaphore = NULL;
dflet 3:a8c249046181 114
dflet 3:a8c249046181 115 void vATask( void * pvParameters )
dflet 3:a8c249046181 116 {
dflet 3:a8c249046181 117 // Semaphore cannot be used before a call to vSemaphoreCreateBinary ().
dflet 3:a8c249046181 118 // This is a macro so pass the variable in directly.
dflet 3:a8c249046181 119 vSemaphoreCreateBinary( xSemaphore );
dflet 3:a8c249046181 120
dflet 3:a8c249046181 121 if( xSemaphore != NULL )
dflet 3:a8c249046181 122 {
dflet 3:a8c249046181 123 // The semaphore was created successfully.
dflet 3:a8c249046181 124 // The semaphore can now be used.
dflet 3:a8c249046181 125 }
dflet 3:a8c249046181 126 }
dflet 3:a8c249046181 127 </pre>
dflet 3:a8c249046181 128 * \defgroup vSemaphoreCreateBinary vSemaphoreCreateBinary
dflet 3:a8c249046181 129 * \ingroup Semaphores
dflet 3:a8c249046181 130 */
dflet 3:a8c249046181 131 #define vSemaphoreCreateBinary( xSemaphore ) \
dflet 3:a8c249046181 132 { \
dflet 3:a8c249046181 133 ( xSemaphore ) = xQueueGenericCreate( ( UBaseType_t ) 1, semSEMAPHORE_QUEUE_ITEM_LENGTH, queueQUEUE_TYPE_BINARY_SEMAPHORE ); \
dflet 3:a8c249046181 134 if( ( xSemaphore ) != NULL ) \
dflet 3:a8c249046181 135 { \
dflet 3:a8c249046181 136 ( void ) xSemaphoreGive( ( xSemaphore ) ); \
dflet 3:a8c249046181 137 } \
dflet 3:a8c249046181 138 }
dflet 3:a8c249046181 139
dflet 3:a8c249046181 140 /**
dflet 3:a8c249046181 141 * semphr. h
dflet 3:a8c249046181 142 * <pre>SemaphoreHandle_t xSemaphoreCreateBinary( void )</pre>
dflet 3:a8c249046181 143 *
dflet 3:a8c249046181 144 * The old vSemaphoreCreateBinary() macro is now deprecated in favour of this
dflet 3:a8c249046181 145 * xSemaphoreCreateBinary() function. Note that binary semaphores created using
dflet 3:a8c249046181 146 * the vSemaphoreCreateBinary() macro are created in a state such that the
dflet 3:a8c249046181 147 * first call to 'take' the semaphore would pass, whereas binary semaphores
dflet 3:a8c249046181 148 * created using xSemaphoreCreateBinary() are created in a state such that the
dflet 3:a8c249046181 149 * the semaphore must first be 'given' before it can be 'taken'.
dflet 3:a8c249046181 150 *
dflet 3:a8c249046181 151 * Function that creates a semaphore by using the existing queue mechanism.
dflet 3:a8c249046181 152 * The queue length is 1 as this is a binary semaphore. The data size is 0
dflet 3:a8c249046181 153 * as nothing is actually stored - all that is important is whether the queue is
dflet 3:a8c249046181 154 * empty or full (the binary semaphore is available or not).
dflet 3:a8c249046181 155 *
dflet 3:a8c249046181 156 * This type of semaphore can be used for pure synchronisation between tasks or
dflet 3:a8c249046181 157 * between an interrupt and a task. The semaphore need not be given back once
dflet 3:a8c249046181 158 * obtained, so one task/interrupt can continuously 'give' the semaphore while
dflet 3:a8c249046181 159 * another continuously 'takes' the semaphore. For this reason this type of
dflet 3:a8c249046181 160 * semaphore does not use a priority inheritance mechanism. For an alternative
dflet 3:a8c249046181 161 * that does use priority inheritance see xSemaphoreCreateMutex().
dflet 3:a8c249046181 162 *
dflet 3:a8c249046181 163 * @return Handle to the created semaphore.
dflet 3:a8c249046181 164 *
dflet 3:a8c249046181 165 * Example usage:
dflet 3:a8c249046181 166 <pre>
dflet 3:a8c249046181 167 SemaphoreHandle_t xSemaphore = NULL;
dflet 3:a8c249046181 168
dflet 3:a8c249046181 169 void vATask( void * pvParameters )
dflet 3:a8c249046181 170 {
dflet 3:a8c249046181 171 // Semaphore cannot be used before a call to vSemaphoreCreateBinary ().
dflet 3:a8c249046181 172 // This is a macro so pass the variable in directly.
dflet 3:a8c249046181 173 xSemaphore = xSemaphoreCreateBinary();
dflet 3:a8c249046181 174
dflet 3:a8c249046181 175 if( xSemaphore != NULL )
dflet 3:a8c249046181 176 {
dflet 3:a8c249046181 177 // The semaphore was created successfully.
dflet 3:a8c249046181 178 // The semaphore can now be used.
dflet 3:a8c249046181 179 }
dflet 3:a8c249046181 180 }
dflet 3:a8c249046181 181 </pre>
dflet 3:a8c249046181 182 * \defgroup vSemaphoreCreateBinary vSemaphoreCreateBinary
dflet 3:a8c249046181 183 * \ingroup Semaphores
dflet 3:a8c249046181 184 */
dflet 3:a8c249046181 185 #define xSemaphoreCreateBinary() xQueueGenericCreate( ( UBaseType_t ) 1, semSEMAPHORE_QUEUE_ITEM_LENGTH, queueQUEUE_TYPE_BINARY_SEMAPHORE )
dflet 3:a8c249046181 186
dflet 3:a8c249046181 187 /**
dflet 3:a8c249046181 188 * semphr. h
dflet 3:a8c249046181 189 * <pre>xSemaphoreTake(
dflet 3:a8c249046181 190 * SemaphoreHandle_t xSemaphore,
dflet 3:a8c249046181 191 * TickType_t xBlockTime
dflet 3:a8c249046181 192 * )</pre>
dflet 3:a8c249046181 193 *
dflet 3:a8c249046181 194 * <i>Macro</i> to obtain a semaphore. The semaphore must have previously been
dflet 3:a8c249046181 195 * created with a call to vSemaphoreCreateBinary(), xSemaphoreCreateMutex() or
dflet 3:a8c249046181 196 * xSemaphoreCreateCounting().
dflet 3:a8c249046181 197 *
dflet 3:a8c249046181 198 * @param xSemaphore A handle to the semaphore being taken - obtained when
dflet 3:a8c249046181 199 * the semaphore was created.
dflet 3:a8c249046181 200 *
dflet 3:a8c249046181 201 * @param xBlockTime The time in ticks to wait for the semaphore to become
dflet 3:a8c249046181 202 * available. The macro portTICK_PERIOD_MS can be used to convert this to a
dflet 3:a8c249046181 203 * real time. A block time of zero can be used to poll the semaphore. A block
dflet 3:a8c249046181 204 * time of portMAX_DELAY can be used to block indefinitely (provided
dflet 3:a8c249046181 205 * INCLUDE_vTaskSuspend is set to 1 in FreeRTOSConfig.h).
dflet 3:a8c249046181 206 *
dflet 3:a8c249046181 207 * @return pdTRUE if the semaphore was obtained. pdFALSE
dflet 3:a8c249046181 208 * if xBlockTime expired without the semaphore becoming available.
dflet 3:a8c249046181 209 *
dflet 3:a8c249046181 210 * Example usage:
dflet 3:a8c249046181 211 <pre>
dflet 3:a8c249046181 212 SemaphoreHandle_t xSemaphore = NULL;
dflet 3:a8c249046181 213
dflet 3:a8c249046181 214 // A task that creates a semaphore.
dflet 3:a8c249046181 215 void vATask( void * pvParameters )
dflet 3:a8c249046181 216 {
dflet 3:a8c249046181 217 // Create the semaphore to guard a shared resource.
dflet 3:a8c249046181 218 vSemaphoreCreateBinary( xSemaphore );
dflet 3:a8c249046181 219 }
dflet 3:a8c249046181 220
dflet 3:a8c249046181 221 // A task that uses the semaphore.
dflet 3:a8c249046181 222 void vAnotherTask( void * pvParameters )
dflet 3:a8c249046181 223 {
dflet 3:a8c249046181 224 // ... Do other things.
dflet 3:a8c249046181 225
dflet 3:a8c249046181 226 if( xSemaphore != NULL )
dflet 3:a8c249046181 227 {
dflet 3:a8c249046181 228 // See if we can obtain the semaphore. If the semaphore is not available
dflet 3:a8c249046181 229 // wait 10 ticks to see if it becomes free.
dflet 3:a8c249046181 230 if( xSemaphoreTake( xSemaphore, ( TickType_t ) 10 ) == pdTRUE )
dflet 3:a8c249046181 231 {
dflet 3:a8c249046181 232 // We were able to obtain the semaphore and can now access the
dflet 3:a8c249046181 233 // shared resource.
dflet 3:a8c249046181 234
dflet 3:a8c249046181 235 // ...
dflet 3:a8c249046181 236
dflet 3:a8c249046181 237 // We have finished accessing the shared resource. Release the
dflet 3:a8c249046181 238 // semaphore.
dflet 3:a8c249046181 239 xSemaphoreGive( xSemaphore );
dflet 3:a8c249046181 240 }
dflet 3:a8c249046181 241 else
dflet 3:a8c249046181 242 {
dflet 3:a8c249046181 243 // We could not obtain the semaphore and can therefore not access
dflet 3:a8c249046181 244 // the shared resource safely.
dflet 3:a8c249046181 245 }
dflet 3:a8c249046181 246 }
dflet 3:a8c249046181 247 }
dflet 3:a8c249046181 248 </pre>
dflet 3:a8c249046181 249 * \defgroup xSemaphoreTake xSemaphoreTake
dflet 3:a8c249046181 250 * \ingroup Semaphores
dflet 3:a8c249046181 251 */
dflet 3:a8c249046181 252 #define xSemaphoreTake( xSemaphore, xBlockTime ) xQueueGenericReceive( ( QueueHandle_t ) ( xSemaphore ), NULL, ( xBlockTime ), pdFALSE )
dflet 3:a8c249046181 253
dflet 3:a8c249046181 254 /**
dflet 3:a8c249046181 255 * semphr. h
dflet 3:a8c249046181 256 * xSemaphoreTakeRecursive(
dflet 3:a8c249046181 257 * SemaphoreHandle_t xMutex,
dflet 3:a8c249046181 258 * TickType_t xBlockTime
dflet 3:a8c249046181 259 * )
dflet 3:a8c249046181 260 *
dflet 3:a8c249046181 261 * <i>Macro</i> to recursively obtain, or 'take', a mutex type semaphore.
dflet 3:a8c249046181 262 * The mutex must have previously been created using a call to
dflet 3:a8c249046181 263 * xSemaphoreCreateRecursiveMutex();
dflet 3:a8c249046181 264 *
dflet 3:a8c249046181 265 * configUSE_RECURSIVE_MUTEXES must be set to 1 in FreeRTOSConfig.h for this
dflet 3:a8c249046181 266 * macro to be available.
dflet 3:a8c249046181 267 *
dflet 3:a8c249046181 268 * This macro must not be used on mutexes created using xSemaphoreCreateMutex().
dflet 3:a8c249046181 269 *
dflet 3:a8c249046181 270 * A mutex used recursively can be 'taken' repeatedly by the owner. The mutex
dflet 3:a8c249046181 271 * doesn't become available again until the owner has called
dflet 3:a8c249046181 272 * xSemaphoreGiveRecursive() for each successful 'take' request. For example,
dflet 3:a8c249046181 273 * if a task successfully 'takes' the same mutex 5 times then the mutex will
dflet 3:a8c249046181 274 * not be available to any other task until it has also 'given' the mutex back
dflet 3:a8c249046181 275 * exactly five times.
dflet 3:a8c249046181 276 *
dflet 3:a8c249046181 277 * @param xMutex A handle to the mutex being obtained. This is the
dflet 3:a8c249046181 278 * handle returned by xSemaphoreCreateRecursiveMutex();
dflet 3:a8c249046181 279 *
dflet 3:a8c249046181 280 * @param xBlockTime The time in ticks to wait for the semaphore to become
dflet 3:a8c249046181 281 * available. The macro portTICK_PERIOD_MS can be used to convert this to a
dflet 3:a8c249046181 282 * real time. A block time of zero can be used to poll the semaphore. If
dflet 3:a8c249046181 283 * the task already owns the semaphore then xSemaphoreTakeRecursive() will
dflet 3:a8c249046181 284 * return immediately no matter what the value of xBlockTime.
dflet 3:a8c249046181 285 *
dflet 3:a8c249046181 286 * @return pdTRUE if the semaphore was obtained. pdFALSE if xBlockTime
dflet 3:a8c249046181 287 * expired without the semaphore becoming available.
dflet 3:a8c249046181 288 *
dflet 3:a8c249046181 289 * Example usage:
dflet 3:a8c249046181 290 <pre>
dflet 3:a8c249046181 291 SemaphoreHandle_t xMutex = NULL;
dflet 3:a8c249046181 292
dflet 3:a8c249046181 293 // A task that creates a mutex.
dflet 3:a8c249046181 294 void vATask( void * pvParameters )
dflet 3:a8c249046181 295 {
dflet 3:a8c249046181 296 // Create the mutex to guard a shared resource.
dflet 3:a8c249046181 297 xMutex = xSemaphoreCreateRecursiveMutex();
dflet 3:a8c249046181 298 }
dflet 3:a8c249046181 299
dflet 3:a8c249046181 300 // A task that uses the mutex.
dflet 3:a8c249046181 301 void vAnotherTask( void * pvParameters )
dflet 3:a8c249046181 302 {
dflet 3:a8c249046181 303 // ... Do other things.
dflet 3:a8c249046181 304
dflet 3:a8c249046181 305 if( xMutex != NULL )
dflet 3:a8c249046181 306 {
dflet 3:a8c249046181 307 // See if we can obtain the mutex. If the mutex is not available
dflet 3:a8c249046181 308 // wait 10 ticks to see if it becomes free.
dflet 3:a8c249046181 309 if( xSemaphoreTakeRecursive( xSemaphore, ( TickType_t ) 10 ) == pdTRUE )
dflet 3:a8c249046181 310 {
dflet 3:a8c249046181 311 // We were able to obtain the mutex and can now access the
dflet 3:a8c249046181 312 // shared resource.
dflet 3:a8c249046181 313
dflet 3:a8c249046181 314 // ...
dflet 3:a8c249046181 315 // For some reason due to the nature of the code further calls to
dflet 3:a8c249046181 316 // xSemaphoreTakeRecursive() are made on the same mutex. In real
dflet 3:a8c249046181 317 // code these would not be just sequential calls as this would make
dflet 3:a8c249046181 318 // no sense. Instead the calls are likely to be buried inside
dflet 3:a8c249046181 319 // a more complex call structure.
dflet 3:a8c249046181 320 xSemaphoreTakeRecursive( xMutex, ( TickType_t ) 10 );
dflet 3:a8c249046181 321 xSemaphoreTakeRecursive( xMutex, ( TickType_t ) 10 );
dflet 3:a8c249046181 322
dflet 3:a8c249046181 323 // The mutex has now been 'taken' three times, so will not be
dflet 3:a8c249046181 324 // available to another task until it has also been given back
dflet 3:a8c249046181 325 // three times. Again it is unlikely that real code would have
dflet 3:a8c249046181 326 // these calls sequentially, but instead buried in a more complex
dflet 3:a8c249046181 327 // call structure. This is just for illustrative purposes.
dflet 3:a8c249046181 328 xSemaphoreGiveRecursive( xMutex );
dflet 3:a8c249046181 329 xSemaphoreGiveRecursive( xMutex );
dflet 3:a8c249046181 330 xSemaphoreGiveRecursive( xMutex );
dflet 3:a8c249046181 331
dflet 3:a8c249046181 332 // Now the mutex can be taken by other tasks.
dflet 3:a8c249046181 333 }
dflet 3:a8c249046181 334 else
dflet 3:a8c249046181 335 {
dflet 3:a8c249046181 336 // We could not obtain the mutex and can therefore not access
dflet 3:a8c249046181 337 // the shared resource safely.
dflet 3:a8c249046181 338 }
dflet 3:a8c249046181 339 }
dflet 3:a8c249046181 340 }
dflet 3:a8c249046181 341 </pre>
dflet 3:a8c249046181 342 * \defgroup xSemaphoreTakeRecursive xSemaphoreTakeRecursive
dflet 3:a8c249046181 343 * \ingroup Semaphores
dflet 3:a8c249046181 344 */
dflet 3:a8c249046181 345 #define xSemaphoreTakeRecursive( xMutex, xBlockTime ) xQueueTakeMutexRecursive( ( xMutex ), ( xBlockTime ) )
dflet 3:a8c249046181 346
dflet 3:a8c249046181 347
dflet 3:a8c249046181 348 /*
dflet 3:a8c249046181 349 * xSemaphoreAltTake() is an alternative version of xSemaphoreTake().
dflet 3:a8c249046181 350 *
dflet 3:a8c249046181 351 * The source code that implements the alternative (Alt) API is much
dflet 3:a8c249046181 352 * simpler because it executes everything from within a critical section.
dflet 3:a8c249046181 353 * This is the approach taken by many other RTOSes, but FreeRTOS.org has the
dflet 3:a8c249046181 354 * preferred fully featured API too. The fully featured API has more
dflet 3:a8c249046181 355 * complex code that takes longer to execute, but makes much less use of
dflet 3:a8c249046181 356 * critical sections. Therefore the alternative API sacrifices interrupt
dflet 3:a8c249046181 357 * responsiveness to gain execution speed, whereas the fully featured API
dflet 3:a8c249046181 358 * sacrifices execution speed to ensure better interrupt responsiveness.
dflet 3:a8c249046181 359 */
dflet 3:a8c249046181 360 #define xSemaphoreAltTake( xSemaphore, xBlockTime ) xQueueAltGenericReceive( ( QueueHandle_t ) ( xSemaphore ), NULL, ( xBlockTime ), pdFALSE )
dflet 3:a8c249046181 361
dflet 3:a8c249046181 362 /**
dflet 3:a8c249046181 363 * semphr. h
dflet 3:a8c249046181 364 * <pre>xSemaphoreGive( SemaphoreHandle_t xSemaphore )</pre>
dflet 3:a8c249046181 365 *
dflet 3:a8c249046181 366 * <i>Macro</i> to release a semaphore. The semaphore must have previously been
dflet 3:a8c249046181 367 * created with a call to vSemaphoreCreateBinary(), xSemaphoreCreateMutex() or
dflet 3:a8c249046181 368 * xSemaphoreCreateCounting(). and obtained using sSemaphoreTake().
dflet 3:a8c249046181 369 *
dflet 3:a8c249046181 370 * This macro must not be used from an ISR. See xSemaphoreGiveFromISR () for
dflet 3:a8c249046181 371 * an alternative which can be used from an ISR.
dflet 3:a8c249046181 372 *
dflet 3:a8c249046181 373 * This macro must also not be used on semaphores created using
dflet 3:a8c249046181 374 * xSemaphoreCreateRecursiveMutex().
dflet 3:a8c249046181 375 *
dflet 3:a8c249046181 376 * @param xSemaphore A handle to the semaphore being released. This is the
dflet 3:a8c249046181 377 * handle returned when the semaphore was created.
dflet 3:a8c249046181 378 *
dflet 3:a8c249046181 379 * @return pdTRUE if the semaphore was released. pdFALSE if an error occurred.
dflet 3:a8c249046181 380 * Semaphores are implemented using queues. An error can occur if there is
dflet 3:a8c249046181 381 * no space on the queue to post a message - indicating that the
dflet 3:a8c249046181 382 * semaphore was not first obtained correctly.
dflet 3:a8c249046181 383 *
dflet 3:a8c249046181 384 * Example usage:
dflet 3:a8c249046181 385 <pre>
dflet 3:a8c249046181 386 SemaphoreHandle_t xSemaphore = NULL;
dflet 3:a8c249046181 387
dflet 3:a8c249046181 388 void vATask( void * pvParameters )
dflet 3:a8c249046181 389 {
dflet 3:a8c249046181 390 // Create the semaphore to guard a shared resource.
dflet 3:a8c249046181 391 vSemaphoreCreateBinary( xSemaphore );
dflet 3:a8c249046181 392
dflet 3:a8c249046181 393 if( xSemaphore != NULL )
dflet 3:a8c249046181 394 {
dflet 3:a8c249046181 395 if( xSemaphoreGive( xSemaphore ) != pdTRUE )
dflet 3:a8c249046181 396 {
dflet 3:a8c249046181 397 // We would expect this call to fail because we cannot give
dflet 3:a8c249046181 398 // a semaphore without first "taking" it!
dflet 3:a8c249046181 399 }
dflet 3:a8c249046181 400
dflet 3:a8c249046181 401 // Obtain the semaphore - don't block if the semaphore is not
dflet 3:a8c249046181 402 // immediately available.
dflet 3:a8c249046181 403 if( xSemaphoreTake( xSemaphore, ( TickType_t ) 0 ) )
dflet 3:a8c249046181 404 {
dflet 3:a8c249046181 405 // We now have the semaphore and can access the shared resource.
dflet 3:a8c249046181 406
dflet 3:a8c249046181 407 // ...
dflet 3:a8c249046181 408
dflet 3:a8c249046181 409 // We have finished accessing the shared resource so can free the
dflet 3:a8c249046181 410 // semaphore.
dflet 3:a8c249046181 411 if( xSemaphoreGive( xSemaphore ) != pdTRUE )
dflet 3:a8c249046181 412 {
dflet 3:a8c249046181 413 // We would not expect this call to fail because we must have
dflet 3:a8c249046181 414 // obtained the semaphore to get here.
dflet 3:a8c249046181 415 }
dflet 3:a8c249046181 416 }
dflet 3:a8c249046181 417 }
dflet 3:a8c249046181 418 }
dflet 3:a8c249046181 419 </pre>
dflet 3:a8c249046181 420 * \defgroup xSemaphoreGive xSemaphoreGive
dflet 3:a8c249046181 421 * \ingroup Semaphores
dflet 3:a8c249046181 422 */
dflet 3:a8c249046181 423 #define xSemaphoreGive( xSemaphore ) xQueueGenericSend( ( QueueHandle_t ) ( xSemaphore ), NULL, semGIVE_BLOCK_TIME, queueSEND_TO_BACK )
dflet 3:a8c249046181 424
dflet 3:a8c249046181 425 /**
dflet 3:a8c249046181 426 * semphr. h
dflet 3:a8c249046181 427 * <pre>xSemaphoreGiveRecursive( SemaphoreHandle_t xMutex )</pre>
dflet 3:a8c249046181 428 *
dflet 3:a8c249046181 429 * <i>Macro</i> to recursively release, or 'give', a mutex type semaphore.
dflet 3:a8c249046181 430 * The mutex must have previously been created using a call to
dflet 3:a8c249046181 431 * xSemaphoreCreateRecursiveMutex();
dflet 3:a8c249046181 432 *
dflet 3:a8c249046181 433 * configUSE_RECURSIVE_MUTEXES must be set to 1 in FreeRTOSConfig.h for this
dflet 3:a8c249046181 434 * macro to be available.
dflet 3:a8c249046181 435 *
dflet 3:a8c249046181 436 * This macro must not be used on mutexes created using xSemaphoreCreateMutex().
dflet 3:a8c249046181 437 *
dflet 3:a8c249046181 438 * A mutex used recursively can be 'taken' repeatedly by the owner. The mutex
dflet 3:a8c249046181 439 * doesn't become available again until the owner has called
dflet 3:a8c249046181 440 * xSemaphoreGiveRecursive() for each successful 'take' request. For example,
dflet 3:a8c249046181 441 * if a task successfully 'takes' the same mutex 5 times then the mutex will
dflet 3:a8c249046181 442 * not be available to any other task until it has also 'given' the mutex back
dflet 3:a8c249046181 443 * exactly five times.
dflet 3:a8c249046181 444 *
dflet 3:a8c249046181 445 * @param xMutex A handle to the mutex being released, or 'given'. This is the
dflet 3:a8c249046181 446 * handle returned by xSemaphoreCreateMutex();
dflet 3:a8c249046181 447 *
dflet 3:a8c249046181 448 * @return pdTRUE if the semaphore was given.
dflet 3:a8c249046181 449 *
dflet 3:a8c249046181 450 * Example usage:
dflet 3:a8c249046181 451 <pre>
dflet 3:a8c249046181 452 SemaphoreHandle_t xMutex = NULL;
dflet 3:a8c249046181 453
dflet 3:a8c249046181 454 // A task that creates a mutex.
dflet 3:a8c249046181 455 void vATask( void * pvParameters )
dflet 3:a8c249046181 456 {
dflet 3:a8c249046181 457 // Create the mutex to guard a shared resource.
dflet 3:a8c249046181 458 xMutex = xSemaphoreCreateRecursiveMutex();
dflet 3:a8c249046181 459 }
dflet 3:a8c249046181 460
dflet 3:a8c249046181 461 // A task that uses the mutex.
dflet 3:a8c249046181 462 void vAnotherTask( void * pvParameters )
dflet 3:a8c249046181 463 {
dflet 3:a8c249046181 464 // ... Do other things.
dflet 3:a8c249046181 465
dflet 3:a8c249046181 466 if( xMutex != NULL )
dflet 3:a8c249046181 467 {
dflet 3:a8c249046181 468 // See if we can obtain the mutex. If the mutex is not available
dflet 3:a8c249046181 469 // wait 10 ticks to see if it becomes free.
dflet 3:a8c249046181 470 if( xSemaphoreTakeRecursive( xMutex, ( TickType_t ) 10 ) == pdTRUE )
dflet 3:a8c249046181 471 {
dflet 3:a8c249046181 472 // We were able to obtain the mutex and can now access the
dflet 3:a8c249046181 473 // shared resource.
dflet 3:a8c249046181 474
dflet 3:a8c249046181 475 // ...
dflet 3:a8c249046181 476 // For some reason due to the nature of the code further calls to
dflet 3:a8c249046181 477 // xSemaphoreTakeRecursive() are made on the same mutex. In real
dflet 3:a8c249046181 478 // code these would not be just sequential calls as this would make
dflet 3:a8c249046181 479 // no sense. Instead the calls are likely to be buried inside
dflet 3:a8c249046181 480 // a more complex call structure.
dflet 3:a8c249046181 481 xSemaphoreTakeRecursive( xMutex, ( TickType_t ) 10 );
dflet 3:a8c249046181 482 xSemaphoreTakeRecursive( xMutex, ( TickType_t ) 10 );
dflet 3:a8c249046181 483
dflet 3:a8c249046181 484 // The mutex has now been 'taken' three times, so will not be
dflet 3:a8c249046181 485 // available to another task until it has also been given back
dflet 3:a8c249046181 486 // three times. Again it is unlikely that real code would have
dflet 3:a8c249046181 487 // these calls sequentially, it would be more likely that the calls
dflet 3:a8c249046181 488 // to xSemaphoreGiveRecursive() would be called as a call stack
dflet 3:a8c249046181 489 // unwound. This is just for demonstrative purposes.
dflet 3:a8c249046181 490 xSemaphoreGiveRecursive( xMutex );
dflet 3:a8c249046181 491 xSemaphoreGiveRecursive( xMutex );
dflet 3:a8c249046181 492 xSemaphoreGiveRecursive( xMutex );
dflet 3:a8c249046181 493
dflet 3:a8c249046181 494 // Now the mutex can be taken by other tasks.
dflet 3:a8c249046181 495 }
dflet 3:a8c249046181 496 else
dflet 3:a8c249046181 497 {
dflet 3:a8c249046181 498 // We could not obtain the mutex and can therefore not access
dflet 3:a8c249046181 499 // the shared resource safely.
dflet 3:a8c249046181 500 }
dflet 3:a8c249046181 501 }
dflet 3:a8c249046181 502 }
dflet 3:a8c249046181 503 </pre>
dflet 3:a8c249046181 504 * \defgroup xSemaphoreGiveRecursive xSemaphoreGiveRecursive
dflet 3:a8c249046181 505 * \ingroup Semaphores
dflet 3:a8c249046181 506 */
dflet 3:a8c249046181 507 #define xSemaphoreGiveRecursive( xMutex ) xQueueGiveMutexRecursive( ( xMutex ) )
dflet 3:a8c249046181 508
dflet 3:a8c249046181 509 /*
dflet 3:a8c249046181 510 * xSemaphoreAltGive() is an alternative version of xSemaphoreGive().
dflet 3:a8c249046181 511 *
dflet 3:a8c249046181 512 * The source code that implements the alternative (Alt) API is much
dflet 3:a8c249046181 513 * simpler because it executes everything from within a critical section.
dflet 3:a8c249046181 514 * This is the approach taken by many other RTOSes, but FreeRTOS.org has the
dflet 3:a8c249046181 515 * preferred fully featured API too. The fully featured API has more
dflet 3:a8c249046181 516 * complex code that takes longer to execute, but makes much less use of
dflet 3:a8c249046181 517 * critical sections. Therefore the alternative API sacrifices interrupt
dflet 3:a8c249046181 518 * responsiveness to gain execution speed, whereas the fully featured API
dflet 3:a8c249046181 519 * sacrifices execution speed to ensure better interrupt responsiveness.
dflet 3:a8c249046181 520 */
dflet 3:a8c249046181 521 #define xSemaphoreAltGive( xSemaphore ) xQueueAltGenericSend( ( QueueHandle_t ) ( xSemaphore ), NULL, semGIVE_BLOCK_TIME, queueSEND_TO_BACK )
dflet 3:a8c249046181 522
dflet 3:a8c249046181 523 /**
dflet 3:a8c249046181 524 * semphr. h
dflet 3:a8c249046181 525 * <pre>
dflet 3:a8c249046181 526 xSemaphoreGiveFromISR(
dflet 3:a8c249046181 527 SemaphoreHandle_t xSemaphore,
dflet 3:a8c249046181 528 BaseType_t *pxHigherPriorityTaskWoken
dflet 3:a8c249046181 529 )</pre>
dflet 3:a8c249046181 530 *
dflet 3:a8c249046181 531 * <i>Macro</i> to release a semaphore. The semaphore must have previously been
dflet 3:a8c249046181 532 * created with a call to vSemaphoreCreateBinary() or xSemaphoreCreateCounting().
dflet 3:a8c249046181 533 *
dflet 3:a8c249046181 534 * Mutex type semaphores (those created using a call to xSemaphoreCreateMutex())
dflet 3:a8c249046181 535 * must not be used with this macro.
dflet 3:a8c249046181 536 *
dflet 3:a8c249046181 537 * This macro can be used from an ISR.
dflet 3:a8c249046181 538 *
dflet 3:a8c249046181 539 * @param xSemaphore A handle to the semaphore being released. This is the
dflet 3:a8c249046181 540 * handle returned when the semaphore was created.
dflet 3:a8c249046181 541 *
dflet 3:a8c249046181 542 * @param pxHigherPriorityTaskWoken xSemaphoreGiveFromISR() will set
dflet 3:a8c249046181 543 * *pxHigherPriorityTaskWoken to pdTRUE if giving the semaphore caused a task
dflet 3:a8c249046181 544 * to unblock, and the unblocked task has a priority higher than the currently
dflet 3:a8c249046181 545 * running task. If xSemaphoreGiveFromISR() sets this value to pdTRUE then
dflet 3:a8c249046181 546 * a context switch should be requested before the interrupt is exited.
dflet 3:a8c249046181 547 *
dflet 3:a8c249046181 548 * @return pdTRUE if the semaphore was successfully given, otherwise errQUEUE_FULL.
dflet 3:a8c249046181 549 *
dflet 3:a8c249046181 550 * Example usage:
dflet 3:a8c249046181 551 <pre>
dflet 3:a8c249046181 552 \#define LONG_TIME 0xffff
dflet 3:a8c249046181 553 \#define TICKS_TO_WAIT 10
dflet 3:a8c249046181 554 SemaphoreHandle_t xSemaphore = NULL;
dflet 3:a8c249046181 555
dflet 3:a8c249046181 556 // Repetitive task.
dflet 3:a8c249046181 557 void vATask( void * pvParameters )
dflet 3:a8c249046181 558 {
dflet 3:a8c249046181 559 for( ;; )
dflet 3:a8c249046181 560 {
dflet 3:a8c249046181 561 // We want this task to run every 10 ticks of a timer. The semaphore
dflet 3:a8c249046181 562 // was created before this task was started.
dflet 3:a8c249046181 563
dflet 3:a8c249046181 564 // Block waiting for the semaphore to become available.
dflet 3:a8c249046181 565 if( xSemaphoreTake( xSemaphore, LONG_TIME ) == pdTRUE )
dflet 3:a8c249046181 566 {
dflet 3:a8c249046181 567 // It is time to execute.
dflet 3:a8c249046181 568
dflet 3:a8c249046181 569 // ...
dflet 3:a8c249046181 570
dflet 3:a8c249046181 571 // We have finished our task. Return to the top of the loop where
dflet 3:a8c249046181 572 // we will block on the semaphore until it is time to execute
dflet 3:a8c249046181 573 // again. Note when using the semaphore for synchronisation with an
dflet 3:a8c249046181 574 // ISR in this manner there is no need to 'give' the semaphore back.
dflet 3:a8c249046181 575 }
dflet 3:a8c249046181 576 }
dflet 3:a8c249046181 577 }
dflet 3:a8c249046181 578
dflet 3:a8c249046181 579 // Timer ISR
dflet 3:a8c249046181 580 void vTimerISR( void * pvParameters )
dflet 3:a8c249046181 581 {
dflet 3:a8c249046181 582 static uint8_t ucLocalTickCount = 0;
dflet 3:a8c249046181 583 static BaseType_t xHigherPriorityTaskWoken;
dflet 3:a8c249046181 584
dflet 3:a8c249046181 585 // A timer tick has occurred.
dflet 3:a8c249046181 586
dflet 3:a8c249046181 587 // ... Do other time functions.
dflet 3:a8c249046181 588
dflet 3:a8c249046181 589 // Is it time for vATask () to run?
dflet 3:a8c249046181 590 xHigherPriorityTaskWoken = pdFALSE;
dflet 3:a8c249046181 591 ucLocalTickCount++;
dflet 3:a8c249046181 592 if( ucLocalTickCount >= TICKS_TO_WAIT )
dflet 3:a8c249046181 593 {
dflet 3:a8c249046181 594 // Unblock the task by releasing the semaphore.
dflet 3:a8c249046181 595 xSemaphoreGiveFromISR( xSemaphore, &xHigherPriorityTaskWoken );
dflet 3:a8c249046181 596
dflet 3:a8c249046181 597 // Reset the count so we release the semaphore again in 10 ticks time.
dflet 3:a8c249046181 598 ucLocalTickCount = 0;
dflet 3:a8c249046181 599 }
dflet 3:a8c249046181 600
dflet 3:a8c249046181 601 if( xHigherPriorityTaskWoken != pdFALSE )
dflet 3:a8c249046181 602 {
dflet 3:a8c249046181 603 // We can force a context switch here. Context switching from an
dflet 3:a8c249046181 604 // ISR uses port specific syntax. Check the demo task for your port
dflet 3:a8c249046181 605 // to find the syntax required.
dflet 3:a8c249046181 606 }
dflet 3:a8c249046181 607 }
dflet 3:a8c249046181 608 </pre>
dflet 3:a8c249046181 609 * \defgroup xSemaphoreGiveFromISR xSemaphoreGiveFromISR
dflet 3:a8c249046181 610 * \ingroup Semaphores
dflet 3:a8c249046181 611 */
dflet 3:a8c249046181 612 #define xSemaphoreGiveFromISR( xSemaphore, pxHigherPriorityTaskWoken ) xQueueGiveFromISR( ( QueueHandle_t ) ( xSemaphore ), ( pxHigherPriorityTaskWoken ) )
dflet 3:a8c249046181 613
dflet 3:a8c249046181 614 /**
dflet 3:a8c249046181 615 * semphr. h
dflet 3:a8c249046181 616 * <pre>
dflet 3:a8c249046181 617 xSemaphoreTakeFromISR(
dflet 3:a8c249046181 618 SemaphoreHandle_t xSemaphore,
dflet 3:a8c249046181 619 BaseType_t *pxHigherPriorityTaskWoken
dflet 3:a8c249046181 620 )</pre>
dflet 3:a8c249046181 621 *
dflet 3:a8c249046181 622 * <i>Macro</i> to take a semaphore from an ISR. The semaphore must have
dflet 3:a8c249046181 623 * previously been created with a call to vSemaphoreCreateBinary() or
dflet 3:a8c249046181 624 * xSemaphoreCreateCounting().
dflet 3:a8c249046181 625 *
dflet 3:a8c249046181 626 * Mutex type semaphores (those created using a call to xSemaphoreCreateMutex())
dflet 3:a8c249046181 627 * must not be used with this macro.
dflet 3:a8c249046181 628 *
dflet 3:a8c249046181 629 * This macro can be used from an ISR, however taking a semaphore from an ISR
dflet 3:a8c249046181 630 * is not a common operation. It is likely to only be useful when taking a
dflet 3:a8c249046181 631 * counting semaphore when an interrupt is obtaining an object from a resource
dflet 3:a8c249046181 632 * pool (when the semaphore count indicates the number of resources available).
dflet 3:a8c249046181 633 *
dflet 3:a8c249046181 634 * @param xSemaphore A handle to the semaphore being taken. This is the
dflet 3:a8c249046181 635 * handle returned when the semaphore was created.
dflet 3:a8c249046181 636 *
dflet 3:a8c249046181 637 * @param pxHigherPriorityTaskWoken xSemaphoreTakeFromISR() will set
dflet 3:a8c249046181 638 * *pxHigherPriorityTaskWoken to pdTRUE if taking the semaphore caused a task
dflet 3:a8c249046181 639 * to unblock, and the unblocked task has a priority higher than the currently
dflet 3:a8c249046181 640 * running task. If xSemaphoreTakeFromISR() sets this value to pdTRUE then
dflet 3:a8c249046181 641 * a context switch should be requested before the interrupt is exited.
dflet 3:a8c249046181 642 *
dflet 3:a8c249046181 643 * @return pdTRUE if the semaphore was successfully taken, otherwise
dflet 3:a8c249046181 644 * pdFALSE
dflet 3:a8c249046181 645 */
dflet 3:a8c249046181 646 #define xSemaphoreTakeFromISR( xSemaphore, pxHigherPriorityTaskWoken ) xQueueReceiveFromISR( ( QueueHandle_t ) ( xSemaphore ), NULL, ( pxHigherPriorityTaskWoken ) )
dflet 3:a8c249046181 647
dflet 3:a8c249046181 648 /**
dflet 3:a8c249046181 649 * semphr. h
dflet 3:a8c249046181 650 * <pre>SemaphoreHandle_t xSemaphoreCreateMutex( void )</pre>
dflet 3:a8c249046181 651 *
dflet 3:a8c249046181 652 * <i>Macro</i> that implements a mutex semaphore by using the existing queue
dflet 3:a8c249046181 653 * mechanism.
dflet 3:a8c249046181 654 *
dflet 3:a8c249046181 655 * Mutexes created using this macro can be accessed using the xSemaphoreTake()
dflet 3:a8c249046181 656 * and xSemaphoreGive() macros. The xSemaphoreTakeRecursive() and
dflet 3:a8c249046181 657 * xSemaphoreGiveRecursive() macros should not be used.
dflet 3:a8c249046181 658 *
dflet 3:a8c249046181 659 * This type of semaphore uses a priority inheritance mechanism so a task
dflet 3:a8c249046181 660 * 'taking' a semaphore MUST ALWAYS 'give' the semaphore back once the
dflet 3:a8c249046181 661 * semaphore it is no longer required.
dflet 3:a8c249046181 662 *
dflet 3:a8c249046181 663 * Mutex type semaphores cannot be used from within interrupt service routines.
dflet 3:a8c249046181 664 *
dflet 3:a8c249046181 665 * See vSemaphoreCreateBinary() for an alternative implementation that can be
dflet 3:a8c249046181 666 * used for pure synchronisation (where one task or interrupt always 'gives' the
dflet 3:a8c249046181 667 * semaphore and another always 'takes' the semaphore) and from within interrupt
dflet 3:a8c249046181 668 * service routines.
dflet 3:a8c249046181 669 *
dflet 3:a8c249046181 670 * @return xSemaphore Handle to the created mutex semaphore. Should be of type
dflet 3:a8c249046181 671 * SemaphoreHandle_t.
dflet 3:a8c249046181 672 *
dflet 3:a8c249046181 673 * Example usage:
dflet 3:a8c249046181 674 <pre>
dflet 3:a8c249046181 675 SemaphoreHandle_t xSemaphore;
dflet 3:a8c249046181 676
dflet 3:a8c249046181 677 void vATask( void * pvParameters )
dflet 3:a8c249046181 678 {
dflet 3:a8c249046181 679 // Semaphore cannot be used before a call to xSemaphoreCreateMutex().
dflet 3:a8c249046181 680 // This is a macro so pass the variable in directly.
dflet 3:a8c249046181 681 xSemaphore = xSemaphoreCreateMutex();
dflet 3:a8c249046181 682
dflet 3:a8c249046181 683 if( xSemaphore != NULL )
dflet 3:a8c249046181 684 {
dflet 3:a8c249046181 685 // The semaphore was created successfully.
dflet 3:a8c249046181 686 // The semaphore can now be used.
dflet 3:a8c249046181 687 }
dflet 3:a8c249046181 688 }
dflet 3:a8c249046181 689 </pre>
dflet 3:a8c249046181 690 * \defgroup vSemaphoreCreateMutex vSemaphoreCreateMutex
dflet 3:a8c249046181 691 * \ingroup Semaphores
dflet 3:a8c249046181 692 */
dflet 3:a8c249046181 693 #define xSemaphoreCreateMutex() xQueueCreateMutex( queueQUEUE_TYPE_MUTEX )
dflet 3:a8c249046181 694
dflet 3:a8c249046181 695
dflet 3:a8c249046181 696 /**
dflet 3:a8c249046181 697 * semphr. h
dflet 3:a8c249046181 698 * <pre>SemaphoreHandle_t xSemaphoreCreateRecursiveMutex( void )</pre>
dflet 3:a8c249046181 699 *
dflet 3:a8c249046181 700 * <i>Macro</i> that implements a recursive mutex by using the existing queue
dflet 3:a8c249046181 701 * mechanism.
dflet 3:a8c249046181 702 *
dflet 3:a8c249046181 703 * Mutexes created using this macro can be accessed using the
dflet 3:a8c249046181 704 * xSemaphoreTakeRecursive() and xSemaphoreGiveRecursive() macros. The
dflet 3:a8c249046181 705 * xSemaphoreTake() and xSemaphoreGive() macros should not be used.
dflet 3:a8c249046181 706 *
dflet 3:a8c249046181 707 * A mutex used recursively can be 'taken' repeatedly by the owner. The mutex
dflet 3:a8c249046181 708 * doesn't become available again until the owner has called
dflet 3:a8c249046181 709 * xSemaphoreGiveRecursive() for each successful 'take' request. For example,
dflet 3:a8c249046181 710 * if a task successfully 'takes' the same mutex 5 times then the mutex will
dflet 3:a8c249046181 711 * not be available to any other task until it has also 'given' the mutex back
dflet 3:a8c249046181 712 * exactly five times.
dflet 3:a8c249046181 713 *
dflet 3:a8c249046181 714 * This type of semaphore uses a priority inheritance mechanism so a task
dflet 3:a8c249046181 715 * 'taking' a semaphore MUST ALWAYS 'give' the semaphore back once the
dflet 3:a8c249046181 716 * semaphore it is no longer required.
dflet 3:a8c249046181 717 *
dflet 3:a8c249046181 718 * Mutex type semaphores cannot be used from within interrupt service routines.
dflet 3:a8c249046181 719 *
dflet 3:a8c249046181 720 * See vSemaphoreCreateBinary() for an alternative implementation that can be
dflet 3:a8c249046181 721 * used for pure synchronisation (where one task or interrupt always 'gives' the
dflet 3:a8c249046181 722 * semaphore and another always 'takes' the semaphore) and from within interrupt
dflet 3:a8c249046181 723 * service routines.
dflet 3:a8c249046181 724 *
dflet 3:a8c249046181 725 * @return xSemaphore Handle to the created mutex semaphore. Should be of type
dflet 3:a8c249046181 726 * SemaphoreHandle_t.
dflet 3:a8c249046181 727 *
dflet 3:a8c249046181 728 * Example usage:
dflet 3:a8c249046181 729 <pre>
dflet 3:a8c249046181 730 SemaphoreHandle_t xSemaphore;
dflet 3:a8c249046181 731
dflet 3:a8c249046181 732 void vATask( void * pvParameters )
dflet 3:a8c249046181 733 {
dflet 3:a8c249046181 734 // Semaphore cannot be used before a call to xSemaphoreCreateMutex().
dflet 3:a8c249046181 735 // This is a macro so pass the variable in directly.
dflet 3:a8c249046181 736 xSemaphore = xSemaphoreCreateRecursiveMutex();
dflet 3:a8c249046181 737
dflet 3:a8c249046181 738 if( xSemaphore != NULL )
dflet 3:a8c249046181 739 {
dflet 3:a8c249046181 740 // The semaphore was created successfully.
dflet 3:a8c249046181 741 // The semaphore can now be used.
dflet 3:a8c249046181 742 }
dflet 3:a8c249046181 743 }
dflet 3:a8c249046181 744 </pre>
dflet 3:a8c249046181 745 * \defgroup vSemaphoreCreateMutex vSemaphoreCreateMutex
dflet 3:a8c249046181 746 * \ingroup Semaphores
dflet 3:a8c249046181 747 */
dflet 3:a8c249046181 748 #define xSemaphoreCreateRecursiveMutex() xQueueCreateMutex( queueQUEUE_TYPE_RECURSIVE_MUTEX )
dflet 3:a8c249046181 749
dflet 3:a8c249046181 750 /**
dflet 3:a8c249046181 751 * semphr. h
dflet 3:a8c249046181 752 * <pre>SemaphoreHandle_t xSemaphoreCreateCounting( UBaseType_t uxMaxCount, UBaseType_t uxInitialCount )</pre>
dflet 3:a8c249046181 753 *
dflet 3:a8c249046181 754 * <i>Macro</i> that creates a counting semaphore by using the existing
dflet 3:a8c249046181 755 * queue mechanism.
dflet 3:a8c249046181 756 *
dflet 3:a8c249046181 757 * Counting semaphores are typically used for two things:
dflet 3:a8c249046181 758 *
dflet 3:a8c249046181 759 * 1) Counting events.
dflet 3:a8c249046181 760 *
dflet 3:a8c249046181 761 * In this usage scenario an event handler will 'give' a semaphore each time
dflet 3:a8c249046181 762 * an event occurs (incrementing the semaphore count value), and a handler
dflet 3:a8c249046181 763 * task will 'take' a semaphore each time it processes an event
dflet 3:a8c249046181 764 * (decrementing the semaphore count value). The count value is therefore
dflet 3:a8c249046181 765 * the difference between the number of events that have occurred and the
dflet 3:a8c249046181 766 * number that have been processed. In this case it is desirable for the
dflet 3:a8c249046181 767 * initial count value to be zero.
dflet 3:a8c249046181 768 *
dflet 3:a8c249046181 769 * 2) Resource management.
dflet 3:a8c249046181 770 *
dflet 3:a8c249046181 771 * In this usage scenario the count value indicates the number of resources
dflet 3:a8c249046181 772 * available. To obtain control of a resource a task must first obtain a
dflet 3:a8c249046181 773 * semaphore - decrementing the semaphore count value. When the count value
dflet 3:a8c249046181 774 * reaches zero there are no free resources. When a task finishes with the
dflet 3:a8c249046181 775 * resource it 'gives' the semaphore back - incrementing the semaphore count
dflet 3:a8c249046181 776 * value. In this case it is desirable for the initial count value to be
dflet 3:a8c249046181 777 * equal to the maximum count value, indicating that all resources are free.
dflet 3:a8c249046181 778 *
dflet 3:a8c249046181 779 * @param uxMaxCount The maximum count value that can be reached. When the
dflet 3:a8c249046181 780 * semaphore reaches this value it can no longer be 'given'.
dflet 3:a8c249046181 781 *
dflet 3:a8c249046181 782 * @param uxInitialCount The count value assigned to the semaphore when it is
dflet 3:a8c249046181 783 * created.
dflet 3:a8c249046181 784 *
dflet 3:a8c249046181 785 * @return Handle to the created semaphore. Null if the semaphore could not be
dflet 3:a8c249046181 786 * created.
dflet 3:a8c249046181 787 *
dflet 3:a8c249046181 788 * Example usage:
dflet 3:a8c249046181 789 <pre>
dflet 3:a8c249046181 790 SemaphoreHandle_t xSemaphore;
dflet 3:a8c249046181 791
dflet 3:a8c249046181 792 void vATask( void * pvParameters )
dflet 3:a8c249046181 793 {
dflet 3:a8c249046181 794 SemaphoreHandle_t xSemaphore = NULL;
dflet 3:a8c249046181 795
dflet 3:a8c249046181 796 // Semaphore cannot be used before a call to xSemaphoreCreateCounting().
dflet 3:a8c249046181 797 // The max value to which the semaphore can count should be 10, and the
dflet 3:a8c249046181 798 // initial value assigned to the count should be 0.
dflet 3:a8c249046181 799 xSemaphore = xSemaphoreCreateCounting( 10, 0 );
dflet 3:a8c249046181 800
dflet 3:a8c249046181 801 if( xSemaphore != NULL )
dflet 3:a8c249046181 802 {
dflet 3:a8c249046181 803 // The semaphore was created successfully.
dflet 3:a8c249046181 804 // The semaphore can now be used.
dflet 3:a8c249046181 805 }
dflet 3:a8c249046181 806 }
dflet 3:a8c249046181 807 </pre>
dflet 3:a8c249046181 808 * \defgroup xSemaphoreCreateCounting xSemaphoreCreateCounting
dflet 3:a8c249046181 809 * \ingroup Semaphores
dflet 3:a8c249046181 810 */
dflet 3:a8c249046181 811 #define xSemaphoreCreateCounting( uxMaxCount, uxInitialCount ) xQueueCreateCountingSemaphore( ( uxMaxCount ), ( uxInitialCount ) )
dflet 3:a8c249046181 812
dflet 3:a8c249046181 813 /**
dflet 3:a8c249046181 814 * semphr. h
dflet 3:a8c249046181 815 * <pre>void vSemaphoreDelete( SemaphoreHandle_t xSemaphore );</pre>
dflet 3:a8c249046181 816 *
dflet 3:a8c249046181 817 * Delete a semaphore. This function must be used with care. For example,
dflet 3:a8c249046181 818 * do not delete a mutex type semaphore if the mutex is held by a task.
dflet 3:a8c249046181 819 *
dflet 3:a8c249046181 820 * @param xSemaphore A handle to the semaphore to be deleted.
dflet 3:a8c249046181 821 *
dflet 3:a8c249046181 822 * \defgroup vSemaphoreDelete vSemaphoreDelete
dflet 3:a8c249046181 823 * \ingroup Semaphores
dflet 3:a8c249046181 824 */
dflet 3:a8c249046181 825 #define vSemaphoreDelete( xSemaphore ) vQueueDelete( ( QueueHandle_t ) ( xSemaphore ) )
dflet 3:a8c249046181 826
dflet 3:a8c249046181 827 /**
dflet 3:a8c249046181 828 * semphr.h
dflet 3:a8c249046181 829 * <pre>TaskHandle_t xSemaphoreGetMutexHolder( SemaphoreHandle_t xMutex );</pre>
dflet 3:a8c249046181 830 *
dflet 3:a8c249046181 831 * If xMutex is indeed a mutex type semaphore, return the current mutex holder.
dflet 3:a8c249046181 832 * If xMutex is not a mutex type semaphore, or the mutex is available (not held
dflet 3:a8c249046181 833 * by a task), return NULL.
dflet 3:a8c249046181 834 *
dflet 3:a8c249046181 835 * Note: This is a good way of determining if the calling task is the mutex
dflet 3:a8c249046181 836 * holder, but not a good way of determining the identity of the mutex holder as
dflet 3:a8c249046181 837 * the holder may change between the function exiting and the returned value
dflet 3:a8c249046181 838 * being tested.
dflet 3:a8c249046181 839 */
dflet 3:a8c249046181 840 #define xSemaphoreGetMutexHolder( xSemaphore ) xQueueGetMutexHolder( ( xSemaphore ) )
dflet 3:a8c249046181 841
dflet 3:a8c249046181 842 #endif /* SEMAPHORE_H */
dflet 3:a8c249046181 843
dflet 3:a8c249046181 844
dflet 3:a8c249046181 845