2 * FreeRTOS Kernel V10.0.0
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3 * Copyright (C) 2017 Amazon.com, Inc. or its affiliates. All Rights Reserved.
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5 * Permission is hereby granted, free of charge, to any person obtaining a copy of
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6 * this software and associated documentation files (the "Software"), to deal in
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7 * the Software without restriction, including without limitation the rights to
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8 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
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9 * the Software, and to permit persons to whom the Software is furnished to do so,
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10 * subject to the following conditions:
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12 * The above copyright notice and this permission notice shall be included in all
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13 * copies or substantial portions of the Software. If you wish to use our Amazon
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14 * FreeRTOS name, please do so in a fair use way that does not cause confusion.
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16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
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18 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
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19 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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20 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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21 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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23 * http://www.FreeRTOS.org
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24 * http://aws.amazon.com/freertos
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26 * 1 tab == 4 spaces!
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31 * This is a simple example that creates two tasks and one queue. One task
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32 * periodically sends a value to the other, which then prints out a message.
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33 * Normally such a simple example would toggle an LED, so the message that is
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34 * printed out is "toggle".
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36 * The demo configures the kernel to be as simple as possible; FreeRTOSConfig.h
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37 * excludes most features, including dynamic memory allocation.
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40 /* Microchip includes. */
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43 /* Scheduler includes. */
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44 #include "FreeRTOS.h"
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48 /* Priorities at which the tasks are created. */
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49 #define mainQUEUE_RECEIVE_TASK_PRIORITY ( tskIDLE_PRIORITY + 2 )
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50 #define mainQUEUE_SEND_TASK_PRIORITY ( tskIDLE_PRIORITY + 1 )
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52 /* The rate at which data is sent to the queue. The 200ms value is converted
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53 to ticks using the portTICK_PERIOD_MS constant. */
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54 #define mainQUEUE_SEND_FREQUENCY_MS ( pdMS_TO_TICKS( 1000UL ) )
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56 /* The number of items the queue can hold. This is 1 as the receive task
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57 will remove items as they are added, meaning the send task should always find
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59 #define mainQUEUE_LENGTH_IN_ITEMS ( 1 )
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61 /*-----------------------------------------------------------*/
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64 * Configures the clocks ready to run the demo.
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66 static void prvSetupHardware( void );
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69 * Simple routine to print a string to ITM for viewing in the Keil serial debug
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72 static void prvITMPrintString( const char *pcString );
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75 * The tasks as described in the comments at the top of this file.
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77 static void prvQueueReceiveTask( void *pvParameters );
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78 static void prvQueueSendTask( void *pvParameters );
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80 /*-----------------------------------------------------------*/
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82 /* configSUPPORT_STATIC_ALLOCATION is 1 and configSUPPORT_DYNAMIC_ALLOCATION is
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83 0 so the queue structure and the queue storage area can only be statically
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84 allocated. See http://TBD for more information.
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85 The queue storage area is dimensioned to hold just one 32-bit value. */
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86 static StaticQueue_t xStaticQueue;
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87 static uint8_t ucQueueStorageArea[ mainQUEUE_LENGTH_IN_ITEMS * sizeof( uint32_t ) ];
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89 /* Holds the handle of the created queue. */
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90 static QueueHandle_t xQueue = NULL;
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92 /* configSUPPORT_STATIC_ALLOCATION is 1 and configSUPPORT_DYNAMIC_ALLOCATION is
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93 0 so the task structure and the stacks used by the tasks can only be statically
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94 allocated. See http://TBD for more information. */
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95 StaticTask_t xRxTCBBuffer, xTxTCBBuffer;
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96 static StackType_t uxRxStackBuffer[ configMINIMAL_STACK_SIZE ], uxTxStackBuffer[ configMINIMAL_STACK_SIZE ];
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98 /*-----------------------------------------------------------*/
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102 /* Set up the hardware ready to run the demo. */
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103 prvSetupHardware();
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104 prvITMPrintString( "Starting\r\n" );
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106 /* Create the queue. xQueueCreateStatic() has two more parameters than the
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107 xQueueCreate() function. The first new parameter is a pointer to the
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108 pre-allocated queue storage area. The second new parameter is a pointer to
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109 the StaticQueue_t structure that will hold the queue state information in
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110 an anonymous way. */
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111 xQueue = xQueueCreateStatic( mainQUEUE_LENGTH_IN_ITEMS, /* The maximum number of items the queue can hold. */
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112 sizeof( uint32_t ), /* The size of each item. */
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113 ucQueueStorageArea, /* The buffer used to hold items within the queue. */
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114 &xStaticQueue ); /* The static queue structure that will hold the state of the queue. */
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116 /* Create the two tasks as described in the comments at the top of this
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118 xTaskCreateStatic( prvQueueReceiveTask, /* Function that implements the task. */
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119 "Rx", /* Human readable name for the task. */
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120 configMINIMAL_STACK_SIZE, /* Task's stack size, in words (not bytes!). */
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121 NULL, /* Parameter to pass into the task. */
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122 mainQUEUE_RECEIVE_TASK_PRIORITY,/* The priority of the task. */
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123 &( uxRxStackBuffer[ 0 ] ), /* The buffer to use as the task's stack. */
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124 &xRxTCBBuffer ); /* The variable that will hold that task's TCB. */
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126 xTaskCreateStatic( prvQueueSendTask, /* Function that implements the task. */
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127 "Tx", /* Human readable name for the task. */
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128 configMINIMAL_STACK_SIZE, /* Task's stack size, in words (not bytes!). */
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129 NULL, /* Parameter to pass into the task. */
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130 mainQUEUE_SEND_TASK_PRIORITY, /* The priority of the task. */
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131 &( uxTxStackBuffer[ 0 ] ), /* The buffer to use as the task's stack. */
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132 &xTxTCBBuffer ); /* The variable that will hold that task's TCB. */
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134 /* Start the scheduler. */
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135 vTaskStartScheduler();
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137 /* If dynamic memory allocation was used then the following code line would
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138 be reached if there was insufficient heap memory available to create either
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139 the timer or idle tasks. As this project is using static memory allocation
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140 then the following line should never be reached. */
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143 /*-----------------------------------------------------------*/
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145 static void prvQueueSendTask( void *pvParameters )
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147 TickType_t xNextWakeTime;
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148 const unsigned long ulValueToSend = 100UL;
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150 /* Initialise xNextWakeTime - this only needs to be done once. */
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151 xNextWakeTime = xTaskGetTickCount();
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155 /* Place this task in the blocked state until it is time to run again.
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156 The block time is specified in ticks, the constant used converts ticks
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157 to ms. While in the Blocked state this task will not consume any CPU
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159 vTaskDelayUntil( &xNextWakeTime, mainQUEUE_SEND_FREQUENCY_MS );
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161 /* Send to the queue - causing the queue receive task to unblock and
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162 toggle the LED. 0 is used as the block time so the sending operation
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163 will not block - it shouldn't need to block as the queue should always
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164 be empty at this point in the code. */
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165 xQueueSend( xQueue, &ulValueToSend, 0U );
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168 /*-----------------------------------------------------------*/
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170 static void prvQueueReceiveTask( void *pvParameters )
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172 unsigned long ulReceivedValue;
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176 /* Wait until something arrives in the queue - this task will block
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177 indefinitely provided INCLUDE_vTaskSuspend is set to 1 in
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178 FreeRTOSConfig.h. */
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179 xQueueReceive( xQueue, &ulReceivedValue, portMAX_DELAY );
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181 /* To get here something must have been received from the queue, but
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182 is it the expected value? If it is, toggle the LED. */
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183 if( ulReceivedValue == 100UL )
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185 /* Output a string in lieu of using an LED. */
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186 prvITMPrintString( "Toggle!\r\n" );
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190 /*-----------------------------------------------------------*/
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192 static void prvSetupHardware( void )
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195 SystemCoreClockUpdate();
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197 /*-----------------------------------------------------------*/
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199 void vApplicationStackOverflowHook( TaskHandle_t pxTask, char *pcTaskName )
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201 /* If configCHECK_FOR_STACK_OVERFLOW is set to either 1 or 2 then this
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202 function will automatically get called if a task overflows its stack. */
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204 ( void ) pcTaskName;
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207 /*-----------------------------------------------------------*/
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209 /* configUSE_STATIC_ALLOCATION is set to 1, so the application must provide an
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210 implementation of vApplicationGetIdleTaskMemory() to provide the memory that is
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211 used by the Idle task. */
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212 void vApplicationGetIdleTaskMemory( StaticTask_t **ppxIdleTaskTCBBuffer, StackType_t **ppxIdleTaskStackBuffer, uint32_t *pulIdleTaskStackSize )
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214 /* If the buffers to be provided to the Idle task are declared inside this
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215 function then they must be declared static - otherwise they will be allocated on
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216 the stack and so not exists after this function exits. */
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217 static StaticTask_t xIdleTaskTCB;
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218 static StackType_t uxIdleTaskStack[ configMINIMAL_STACK_SIZE ];
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220 /* Pass out a pointer to the StaticTask_t structure in which the Idle task's
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221 state will be stored. */
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222 *ppxIdleTaskTCBBuffer = &xIdleTaskTCB;
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224 /* Pass out the array that will be used as the Idle task's stack. */
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225 *ppxIdleTaskStackBuffer = uxIdleTaskStack;
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227 /* Pass out the size of the array pointed to by *ppxIdleTaskStackBuffer.
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228 Note that, as the array is necessarily of type StackType_t,
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229 configMINIMAL_STACK_SIZE is specified in words, not bytes. */
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230 *pulIdleTaskStackSize = configMINIMAL_STACK_SIZE;
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232 /*-----------------------------------------------------------*/
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234 /* configUSE_STATIC_ALLOCATION and configUSE_TIMERS are both set to 1, so the
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235 application must provide an implementation of vApplicationGetTimerTaskMemory()
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236 to provide the memory that is used by the Timer service task. */
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237 void vApplicationGetTimerTaskMemory( StaticTask_t **ppxTimerTaskTCBBuffer, StackType_t **ppxTimerTaskStackBuffer, uint32_t *pulTimerTaskStackSize )
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239 /* If the buffers to be provided to the Timer task are declared inside this
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240 function then they must be declared static - otherwise they will be allocated on
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241 the stack and so not exists after this function exits. */
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242 static StaticTask_t xTimerTaskTCB;
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243 static StackType_t uxTimerTaskStack[ configTIMER_TASK_STACK_DEPTH ];
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245 /* Pass out a pointer to the StaticTask_t structure in which the Timer
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246 task's state will be stored. */
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247 *ppxTimerTaskTCBBuffer = &xTimerTaskTCB;
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249 /* Pass out the array that will be used as the Timer task's stack. */
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250 *ppxTimerTaskStackBuffer = uxTimerTaskStack;
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252 /* Pass out the size of the array pointed to by *ppxTimerTaskStackBuffer.
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253 Note that, as the array is necessarily of type StackType_t,
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254 configMINIMAL_STACK_SIZE is specified in words, not bytes. */
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255 *pulTimerTaskStackSize = configTIMER_TASK_STACK_DEPTH;
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257 /*-----------------------------------------------------------*/
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259 static void prvITMPrintString( const char *pcString )
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261 while( *pcString != 0x00 )
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263 ITM_SendChar( *pcString );
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267 /*-----------------------------------------------------------*/
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