2 FreeRTOS V7.0.1 - 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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61 * main-blinky.c is included when the "Blinky" build configuration is used.
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62 * main-full.c is included when the "Full" build configuration is used.
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64 * main-blinky.c (this file) defines a very simple demo that creates two tasks,
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65 * one queue, and one timer. It also demonstrates how Cortex-M3 interrupts can
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66 * interact with FreeRTOS tasks/timers.
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68 * This simple demo project runs on the SK-FM3-100PMC evaluation board, which
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69 * is populated with an MB9B500 microcontroller.
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71 * The idle hook function:
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72 * The idle hook function demonstrates how to query the amount of FreeRTOS heap
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73 * space that is remaining (see vApplicationIdleHook() defined in this file).
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75 * The main() Function:
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76 * main() creates one software timer, one queue, and two tasks. It then starts
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79 * The Queue Send Task:
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80 * The queue send task is implemented by the prvQueueSendTask() function in
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81 * this file. prvQueueSendTask() sits in a loop that causes it to repeatedly
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82 * block for 200 milliseconds, before sending the value 100 to the queue that
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83 * was created within main(). Once the value is sent, the task loops back
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84 * around to block for another 200 milliseconds.
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86 * The Queue Receive Task:
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87 * The queue receive task is implemented by the prvQueueReceiveTask() function
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88 * in this file. prvQueueReceiveTask() sits in a loop that causes it to
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89 * repeatedly attempt to read data from the queue that was created within
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90 * main(). When data is received, the task checks the value of the data, and
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91 * if the value equals the expected 100, toggles an LED on the 7 segment
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92 * display. The 'block time' parameter passed to the queue receive function
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93 * specifies that the task should be held in the Blocked state indefinitely to
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94 * wait for data to be available on the queue. The queue receive task will only
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95 * leave the Blocked state when the queue send task writes to the queue. As the
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96 * queue send task writes to the queue every 200 milliseconds, the queue receive
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97 * task leaves the Blocked state every 200 milliseconds, and therefore toggles
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98 * the LED every 200 milliseconds.
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100 * The LED Software Timer and the Button Interrupt:
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101 * The user button SW2 is configured to generate an interrupt each time it is
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102 * pressed. The interrupt service routine switches an LED in the 7 segment
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103 * display on, and resets the LED software timer. The LED timer has a 5000
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104 * millisecond (5 second) period, and uses a callback function that is defined
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105 * to just turn the LED off again. Therefore, pressing the user button will
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106 * turn the LED on, and the LED will remain on until a full five seconds pass
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107 * without the button being pressed.
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110 /* Kernel includes. */
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111 #include "FreeRTOS.h"
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114 #include "timers.h"
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116 /* Freescale includes. */
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117 #include "common.h"
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119 /* Priorities at which the tasks are created. */
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120 #define mainQUEUE_RECEIVE_TASK_PRIORITY ( tskIDLE_PRIORITY + 2 )
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121 #define mainQUEUE_SEND_TASK_PRIORITY ( tskIDLE_PRIORITY + 1 )
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123 /* The rate at which data is sent to the queue, specified in milliseconds, and
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124 converted to ticks using the portTICK_RATE_MS constant. */
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125 #define mainQUEUE_SEND_FREQUENCY_MS ( 200 / portTICK_RATE_MS )
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127 /* The LED will remain on until the button has not been pushed for a full
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129 #define mainBUTTON_LED_TIMER_PERIOD_MS ( 5000UL / portTICK_RATE_MS )
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131 /* The number of items the queue can hold. This is 1 as the receive task
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132 will remove items as they are added, meaning the send task should always find
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133 the queue empty. */
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134 #define mainQUEUE_LENGTH ( 1 )
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136 /* The LED toggle by the queue receive task (blue). */
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137 #define mainTASK_CONTROLLED_LED ( 1UL << 10UL )
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139 /* The LED turned on by the button interrupt, and turned off by the LED timer. */
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140 #define mainTIMER_CONTROLLED_LED ( 1UL << 29UL )
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142 /* The vector used by the GPIO port E. Button SW2 is configured to generate
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143 an interrput on this port. */
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144 #define mainGPIO_E_VECTOR ( 107 - 16 )
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146 /* A block time of zero simply means "don't block". */
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147 #define mainDONT_BLOCK ( 0UL )
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149 /*-----------------------------------------------------------*/
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152 * Setup the NVIC, LED outputs, and button inputs.
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154 static void prvSetupHardware( void );
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157 * The tasks as described in the comments at the top of this file.
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159 static void prvQueueReceiveTask( void *pvParameters );
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160 static void prvQueueSendTask( void *pvParameters );
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163 * The LED timer callback function. This does nothing but switch off the
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164 * LED defined by the mainTIMER_CONTROLLED_LED constant.
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166 static void prvButtonLEDTimerCallback( xTimerHandle xTimer );
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168 /*-----------------------------------------------------------*/
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170 /* The queue used by both tasks. */
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171 static xQueueHandle xQueue = NULL;
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173 /* The LED software timer. This uses prvButtonLEDTimerCallback() as its callback
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175 static xTimerHandle xButtonLEDTimer = NULL;
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177 /*-----------------------------------------------------------*/
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181 /* Configure the NVIC, LED outputs and button inputs. */
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182 prvSetupHardware();
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184 /* Create the queue. */
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185 xQueue = xQueueCreate( mainQUEUE_LENGTH, sizeof( unsigned long ) );
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187 if( xQueue != NULL )
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189 /* Start the two tasks as described in the comments at the top of this
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191 xTaskCreate( prvQueueReceiveTask, ( signed char * ) "Rx", configMINIMAL_STACK_SIZE, NULL, mainQUEUE_RECEIVE_TASK_PRIORITY, NULL );
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192 xTaskCreate( prvQueueSendTask, ( signed char * ) "TX", configMINIMAL_STACK_SIZE, NULL, mainQUEUE_SEND_TASK_PRIORITY, NULL );
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194 /* Create the software timer that is responsible for turning off the LED
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195 if the button is not pushed within 5000ms, as described at the top of
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197 xButtonLEDTimer = xTimerCreate( ( const signed char * ) "ButtonLEDTimer", /* A text name, purely to help debugging. */
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198 mainBUTTON_LED_TIMER_PERIOD_MS, /* The timer period, in this case 5000ms (5s). */
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199 pdFALSE, /* This is a one shot timer, so xAutoReload is set to pdFALSE. */
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200 ( void * ) 0, /* The ID is not used, so can be set to anything. */
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201 prvButtonLEDTimerCallback /* The callback function that switches the LED off. */
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204 /* Start the tasks and timer running. */
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205 vTaskStartScheduler();
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208 /* If all is well, the scheduler will now be running, and the following line
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209 will never be reached. If the following line does execute, then there was
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210 insufficient FreeRTOS heap memory available for the idle and/or timer tasks
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211 to be created. See the memory management section on the FreeRTOS web site
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212 for more details. */
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215 /*-----------------------------------------------------------*/
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217 static void prvButtonLEDTimerCallback( xTimerHandle xTimer )
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219 /* The timer has expired - so no button pushes have occurred in the last
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220 five seconds - turn the LED off. NOTE - accessing the LED port should use
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221 a critical section because it is accessed from multiple tasks, and the
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222 button interrupt - in this trivial case, for simplicity, the critical
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223 section is omitted. */
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224 GPIOA_PDOR |= GPIO_PDOR_PDO( mainTIMER_CONTROLLED_LED );
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226 /*-----------------------------------------------------------*/
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228 /* The ISR executed when the user button is pushed. */
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229 void vPort_E_ISRHandler( void )
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231 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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233 /* The button was pushed, so ensure the LED is on before resetting the
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234 LED timer. The LED timer will turn the LED off if the button is not
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235 pushed within 5000ms. */
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236 GPIOA_PDOR &= ~GPIO_PDOR_PDO( mainTIMER_CONTROLLED_LED );
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238 /* This interrupt safe FreeRTOS function can be called from this interrupt
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239 because the interrupt priority is below the
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240 configMAX_SYSCALL_INTERRUPT_PRIORITY setting in FreeRTOSConfig.h. */
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241 xTimerResetFromISR( xButtonLEDTimer, &xHigherPriorityTaskWoken );
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243 /* Clear the interrupt before leaving. This just clears all the interrupts
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244 for simplicity, as only one is actually used in this simple demo anyway. */
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245 PORTE_ISFR = 0xFFFFFFFFUL;
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247 /* If calling xTimerResetFromISR() caused a task (in this case the timer
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248 service/daemon task) to unblock, and the unblocked task has a priority
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249 higher than or equal to the task that was interrupted, then
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250 xHigherPriorityTaskWoken will now be set to pdTRUE, and calling
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251 portEND_SWITCHING_ISR() will ensure the unblocked task runs next. */
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252 portEND_SWITCHING_ISR( xHigherPriorityTaskWoken );
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254 /*-----------------------------------------------------------*/
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256 static void prvQueueSendTask( void *pvParameters )
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258 portTickType xNextWakeTime;
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259 const unsigned long ulValueToSend = 100UL;
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261 /* Initialise xNextWakeTime - this only needs to be done once. */
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262 xNextWakeTime = xTaskGetTickCount();
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266 /* Place this task in the blocked state until it is time to run again.
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267 The block time is specified in ticks, the constant used converts ticks
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268 to ms. While in the Blocked state this task will not consume any CPU
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270 vTaskDelayUntil( &xNextWakeTime, mainQUEUE_SEND_FREQUENCY_MS );
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272 /* Send to the queue - causing the queue receive task to unblock and
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273 toggle an LED. 0 is used as the block time so the sending operation
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274 will not block - it shouldn't need to block as the queue should always
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275 be empty at this point in the code. */
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276 xQueueSend( xQueue, &ulValueToSend, mainDONT_BLOCK );
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279 /*-----------------------------------------------------------*/
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281 static void prvQueueReceiveTask( void *pvParameters )
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283 unsigned long ulReceivedValue;
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287 /* Wait until something arrives in the queue - this task will block
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288 indefinitely provided INCLUDE_vTaskSuspend is set to 1 in
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289 FreeRTOSConfig.h. */
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290 xQueueReceive( xQueue, &ulReceivedValue, portMAX_DELAY );
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292 /* To get here something must have been received from the queue, but
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293 is it the expected value? If it is, toggle the LED. */
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294 if( ulReceivedValue == 100UL )
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296 /* NOTE - accessing the LED port should use a critical section
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297 because it is accessed from multiple tasks, and the button interrupt
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298 - in this trivial case, for simplicity, the critical section is
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300 GPIOA_PTOR |= GPIO_PDOR_PDO( mainTASK_CONTROLLED_LED );
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304 /*-----------------------------------------------------------*/
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306 static void prvSetupHardware( void )
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308 /* Enable the interrupt on SW1. */
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309 PORTE_PCR26 = PORT_PCR_MUX( 1 ) | PORT_PCR_IRQC( 0xA ) | PORT_PCR_PE_MASK | PORT_PCR_PS_MASK;
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311 enable_irq( mainGPIO_E_VECTOR );
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312 set_irq_priority( mainGPIO_E_VECTOR, configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY );
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314 /* Set PTA10, PTA11, PTA28, and PTA29 (connected to LED's) for GPIO
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316 PORTA_PCR10 = ( 0 | PORT_PCR_MUX( 1 ) );
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317 PORTA_PCR11 = ( 0 | PORT_PCR_MUX( 1 ) );
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318 PORTA_PCR28 = ( 0 | PORT_PCR_MUX( 1 ) );
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319 PORTA_PCR29 = ( 0 | PORT_PCR_MUX( 1 ) );
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321 /* Change PTA10, PTA29 to outputs. */
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322 GPIOA_PDDR=GPIO_PDDR_PDD( mainTASK_CONTROLLED_LED | mainTIMER_CONTROLLED_LED );
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324 /* Start with LEDs off. */
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327 /*-----------------------------------------------------------*/
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329 void vApplicationMallocFailedHook( void )
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331 /* Called if a call to pvPortMalloc() fails because there is insufficient
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332 free memory available in the FreeRTOS heap. pvPortMalloc() is called
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333 internally by FreeRTOS API functions that create tasks, queues, software
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334 timers, and semaphores. The size of the FreeRTOS heap is set by the
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335 configTOTAL_HEAP_SIZE configuration constant in FreeRTOSConfig.h. */
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336 taskDISABLE_INTERRUPTS();
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339 /*-----------------------------------------------------------*/
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341 void vApplicationStackOverflowHook( xTaskHandle *pxTask, signed char *pcTaskName )
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343 ( void ) pcTaskName;
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346 /* Run time stack overflow checking is performed if
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347 configconfigCHECK_FOR_STACK_OVERFLOW is defined to 1 or 2. This hook
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348 function is called if a stack overflow is detected. */
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349 taskDISABLE_INTERRUPTS();
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352 /*-----------------------------------------------------------*/
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354 void vApplicationTickHook( void )
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356 /* A tick hook is used by the "Full" build configuration. The Full and
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357 blinky build configurations share a FreeRTOSConfig.h header file, so this
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358 simple build configuration also has to define a tick hook - even though it
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359 does not actually use it for anything. */
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361 /*-----------------------------------------------------------*/
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363 void vApplicationIdleHook( void )
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365 volatile size_t xFreeHeapSpace;
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367 /* This function is called on each cycle of the idle task. In this case it
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368 does nothing useful, other than report the amount of FreeRTOS heap that
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369 remains unallocated. */
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370 xFreeHeapSpace = xPortGetFreeHeapSize();
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372 if( xFreeHeapSpace > 100 )
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374 /* By now, the kernel has allocated everything it is going to, so
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375 if there is a lot of heap remaining unallocated then
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376 the value of configTOTAL_HEAP_SIZE in FreeRTOSConfig.h can be
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377 reduced accordingly. */
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380 /*-----------------------------------------------------------*/
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