FreeRTOS/Common/Minimal/crflash.c

   1 /*
   2     FreeRTOS V6.0.5 - Copyright (C) 2010 Real Time Engineers Ltd.
   3
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  24
  25     This file is part of the FreeRTOS distribution.
  26
  27     FreeRTOS is free software; you can redistribute it and/or modify it under
  28     the terms of the GNU General Public License (version 2) as published by the
  29     Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
  30     ***NOTE*** The exception to the GPL is included to allow you to distribute
  31     a combined work that includes FreeRTOS without being obliged to provide the
  32     source code for proprietary components outside of the FreeRTOS kernel.
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  35     FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  36     more details. You should have received a copy of the GNU General Public
  37     License and the FreeRTOS license exception along with FreeRTOS; if not it
  38     can be viewed here: http://www.freertos.org/a00114.html and also obtained
  39     by writing to Richard Barry, contact details for whom are available on the
  40     FreeRTOS WEB site.
  41
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  44     http://www.FreeRTOS.org - Documentation, latest information, license and
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  52 */
  53
  54 /*
  55  * This demo application file demonstrates the use of queues to pass data
  56  * between co-routines.
  57  *
  58  * N represents the number of 'fixed delay' co-routines that are created and
  59  * is set during initialisation.
  60  *
  61  * N 'fixed delay' co-routines are created that just block for a fixed
  62  * period then post the number of an LED onto a queue.  Each such co-routine
  63  * uses a different block period.  A single 'flash' co-routine is also created
  64  * that blocks on the same queue, waiting for the number of the next LED it
  65  * should flash.  Upon receiving a number it simply toggle the instructed LED
  66  * then blocks on the queue once more.  In this manner each LED from LED 0 to
  67  * LED N-1 is caused to flash at a different rate.
  68  *
  69  * The 'fixed delay' co-routines are created with co-routine priority 0.  The
  70  * flash co-routine is created with co-routine priority 1.  This means that
  71  * the queue should never contain more than a single item.  This is because
  72  * posting to the queue will unblock the 'flash' co-routine, and as this has
  73  * a priority greater than the tasks posting to the queue it is guaranteed to
  74  * have emptied the queue and blocked once again before the queue can contain
  75  * any more date.  An error is indicated if an attempt to post data to the
  76  * queue fails - indicating that the queue is already full.
  77  *
  78  */
  79
  80 /* Scheduler includes. */
  81 #include "FreeRTOS.h"
  82 #include "croutine.h"
  83 #include "queue.h"
  84
  85 /* Demo application includes. */
  86 #include "partest.h"
  87 #include "crflash.h"
  88
  89 /* The queue should only need to be of length 1.  See the description at the
  90 top of the file. */
  91 #define crfQUEUE_LENGTH         1
  92
  93 #define crfFIXED_DELAY_PRIORITY         0
  94 #define crfFLASH_PRIORITY                       1
  95
  96 /* Only one flash co-routine is created so the index is not significant. */
  97 #define crfFLASH_INDEX                          0
  98
  99 /* Don't allow more than crfMAX_FLASH_TASKS 'fixed delay' co-routines to be
 100 created. */
 101 #define crfMAX_FLASH_TASKS                      8
 102
 103 /* We don't want to block when posting to the queue. */
 104 #define crfPOSTING_BLOCK_TIME           0
 105
 106 /*
 107  * The 'fixed delay' co-routine as described at the top of the file.
 108  */
 109 static void prvFixedDelayCoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex );
 110
 111 /*
 112  * The 'flash' co-routine as described at the top of the file.
 113  */
 114 static void prvFlashCoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex );
 115
 116 /* The queue used to pass data between the 'fixed delay' co-routines and the
 117 'flash' co-routine. */
 118 static xQueueHandle xFlashQueue;
 119
 120 /* This will be set to pdFALSE if we detect an error. */
 121 static portBASE_TYPE xCoRoutineFlashStatus = pdPASS;
 122
 123 /*-----------------------------------------------------------*/
 124
 125 /*
 126  * See the header file for details.
 127  */
 128 void vStartFlashCoRoutines( unsigned portBASE_TYPE uxNumberToCreate )
 129 {
 130 unsigned portBASE_TYPE uxIndex;
 131
 132         if( uxNumberToCreate > crfMAX_FLASH_TASKS )
 133         {
 134                 uxNumberToCreate = crfMAX_FLASH_TASKS;
 135         }
 136
 137         /* Create the queue used to pass data between the co-routines. */
 138         xFlashQueue = xQueueCreate( crfQUEUE_LENGTH, sizeof( unsigned portBASE_TYPE ) );
 139
 140         if( xFlashQueue )
 141         {
 142                 /* Create uxNumberToCreate 'fixed delay' co-routines. */
 143                 for( uxIndex = 0; uxIndex < uxNumberToCreate; uxIndex++ )
 144                 {
 145                         xCoRoutineCreate( prvFixedDelayCoRoutine, crfFIXED_DELAY_PRIORITY, uxIndex );
 146                 }
 147
 148                 /* Create the 'flash' co-routine. */
 149                 xCoRoutineCreate( prvFlashCoRoutine, crfFLASH_PRIORITY, crfFLASH_INDEX );
 150         }
 151 }
 152 /*-----------------------------------------------------------*/
 153
 154 static void prvFixedDelayCoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
 155 {
 156 /* Even though this is a co-routine the xResult variable does not need to be
 157 static as we do not need it to maintain its state between blocks. */
 158 signed portBASE_TYPE xResult;
 159 /* The uxIndex parameter of the co-routine function is used as an index into
 160 the xFlashRates array to obtain the delay period to use. */
 161 static const portTickType xFlashRates[ crfMAX_FLASH_TASKS ] = { 150 / portTICK_RATE_MS,
 162                                                                                                                                 200 / portTICK_RATE_MS,
 163                                                                                                                                 250 / portTICK_RATE_MS,
 164                                                                                                                                 300 / portTICK_RATE_MS,
 165                                                                                                                                 350 / portTICK_RATE_MS,
 166                                                                                                                                 400 / portTICK_RATE_MS,
 167                                                                                                                                 450 / portTICK_RATE_MS,
 168                                                                                                                                 500  / portTICK_RATE_MS };
 169
 170         /* Co-routines MUST start with a call to crSTART. */
 171         crSTART( xHandle );
 172
 173         for( ;; )
 174         {
 175                 /* Post our uxIndex value onto the queue.  This is used as the LED to
 176                 flash. */
 177                 crQUEUE_SEND( xHandle, xFlashQueue, ( void * ) &uxIndex, crfPOSTING_BLOCK_TIME, &xResult );
 178
 179                 if( xResult != pdPASS )
 180                 {
 181                         /* For the reasons stated at the top of the file we should always
 182                         find that we can post to the queue.  If we could not then an error
 183                         has occurred. */
 184                         xCoRoutineFlashStatus = pdFAIL;
 185                 }
 186
 187                 crDELAY( xHandle, xFlashRates[ uxIndex ] );
 188         }
 189
 190         /* Co-routines MUST end with a call to crEND. */
 191         crEND();
 192 }
 193 /*-----------------------------------------------------------*/
 194
 195 static void prvFlashCoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
 196 {
 197 /* Even though this is a co-routine the variable do not need to be
 198 static as we do not need it to maintain their state between blocks. */
 199 signed portBASE_TYPE xResult;
 200 unsigned portBASE_TYPE uxLEDToFlash;
 201
 202         /* Co-routines MUST start with a call to crSTART. */
 203         crSTART( xHandle );
 204         ( void ) uxIndex;
 205
 206         for( ;; )
 207         {
 208                 /* Block to wait for the number of the LED to flash. */
 209                 crQUEUE_RECEIVE( xHandle, xFlashQueue, &uxLEDToFlash, portMAX_DELAY, &xResult );
 210
 211                 if( xResult != pdPASS )
 212                 {
 213                         /* We would not expect to wake unless we received something. */
 214                         xCoRoutineFlashStatus = pdFAIL;
 215                 }
 216                 else
 217                 {
 218                         /* We received the number of an LED to flash - flash it! */
 219                         vParTestToggleLED( uxLEDToFlash );
 220                 }
 221         }
 222
 223         /* Co-routines MUST end with a call to crEND. */
 224         crEND();
 225 }
 226 /*-----------------------------------------------------------*/
 227
 228 portBASE_TYPE xAreFlashCoRoutinesStillRunning( void )
 229 {
 230         /* Return pdPASS or pdFAIL depending on whether an error has been detected
 231         or not. */
 232         return xCoRoutineFlashStatus;
 233 }
 234