2 FreeRTOS V8.0.1 - Copyright (C) 2014 Real Time Engineers Ltd.
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5 VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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7 ***************************************************************************
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9 * FreeRTOS provides completely free yet professionally developed, *
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10 * robust, strictly quality controlled, supported, and cross *
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11 * platform software that has become a de facto standard. *
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13 * Help yourself get started quickly and support the FreeRTOS *
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14 * project by purchasing a FreeRTOS tutorial book, reference *
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15 * manual, or both from: http://www.FreeRTOS.org/Documentation *
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19 ***************************************************************************
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21 This file is part of the FreeRTOS distribution.
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23 FreeRTOS is free software; you can redistribute it and/or modify it under
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24 the terms of the GNU General Public License (version 2) as published by the
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25 Free Software Foundation >>!AND MODIFIED BY!<< the FreeRTOS exception.
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27 >>! NOTE: The modification to the GPL is included to allow you to !<<
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28 >>! distribute a combined work that includes FreeRTOS without being !<<
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29 >>! obliged to provide the source code for proprietary components !<<
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30 >>! outside of the FreeRTOS kernel. !<<
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32 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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33 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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34 FOR A PARTICULAR PURPOSE. Full license text is available from the following
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35 link: http://www.freertos.org/a00114.html
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39 ***************************************************************************
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41 * Having a problem? Start by reading the FAQ "My application does *
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42 * not run, what could be wrong?" *
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44 * http://www.FreeRTOS.org/FAQHelp.html *
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46 ***************************************************************************
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48 http://www.FreeRTOS.org - Documentation, books, training, latest versions,
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49 license and Real Time Engineers Ltd. contact details.
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51 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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52 including FreeRTOS+Trace - an indispensable productivity tool, a DOS
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53 compatible FAT file system, and our tiny thread aware UDP/IP stack.
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55 http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
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56 Integrity Systems to sell under the OpenRTOS brand. Low cost OpenRTOS
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57 licenses offer ticketed support, indemnification and middleware.
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59 http://www.SafeRTOS.com - High Integrity Systems also provide a safety
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60 engineered and independently SIL3 certified version for use in safety and
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61 mission critical applications that require provable dependability.
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68 * This project contains an application demonstrating the use of the
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69 * FreeRTOS.org mini real time scheduler on the Luminary Micro LM3S811 Eval
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70 * board. See http://www.FreeRTOS.org for more information.
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72 * main() simply sets up the hardware, creates all the demo application tasks,
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73 * then starts the scheduler. http://www.freertos.org/a00102.html provides
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74 * more information on the standard demo tasks.
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76 * In addition to a subset of the standard demo application tasks, main.c also
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77 * defines the following tasks:
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79 * + A 'Print' task. The print task is the only task permitted to access the
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80 * LCD - thus ensuring mutual exclusion and consistent access to the resource.
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81 * Other tasks do not access the LCD directly, but instead send the text they
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82 * wish to display to the print task. The print task spends most of its time
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83 * blocked - only waking when a message is queued for display.
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85 * + A 'Button handler' task. The eval board contains a user push button that
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86 * is configured to generate interrupts. The interrupt handler uses a
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87 * semaphore to wake the button handler task - demonstrating how the priority
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88 * mechanism can be used to defer interrupt processing to the task level. The
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89 * button handler task sends a message both to the LCD (via the print task) and
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90 * the UART where it can be viewed using a dumb terminal (via the UART to USB
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91 * converter on the eval board). NOTES: The dumb terminal must be closed in
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92 * order to reflash the microcontroller. A very basic interrupt driven UART
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93 * driver is used that does not use the FIFO. 19200 baud is used.
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95 * + A 'check' task. The check task only executes every five seconds but has a
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96 * high priority so is guaranteed to get processor time. Its function is to
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97 * check that all the other tasks are still operational and that no errors have
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98 * been detected at any time. If no errors have every been detected 'PASS' is
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99 * written to the display (via the print task) - if an error has ever been
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100 * detected the message is changed to 'FAIL'. The position of the message is
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101 * changed for each write.
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106 /* Environment includes. */
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107 #include "DriverLib.h"
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109 /* Scheduler includes. */
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110 #include "FreeRTOS.h"
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113 #include "semphr.h"
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115 /* Demo app includes. */
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116 #include "integer.h"
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118 #include "semtest.h"
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119 #include "BlockQ.h"
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121 /* Delay between cycles of the 'check' task. */
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122 #define mainCHECK_DELAY ( ( TickType_t ) 5000 / portTICK_PERIOD_MS )
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124 /* UART configuration - note this does not use the FIFO so is not very
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126 #define mainBAUD_RATE ( 19200 )
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127 #define mainFIFO_SET ( 0x10 )
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129 /* Demo task priorities. */
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130 #define mainQUEUE_POLL_PRIORITY ( tskIDLE_PRIORITY + 2 )
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131 #define mainCHECK_TASK_PRIORITY ( tskIDLE_PRIORITY + 3 )
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132 #define mainSEM_TEST_PRIORITY ( tskIDLE_PRIORITY + 1 )
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133 #define mainBLOCK_Q_PRIORITY ( tskIDLE_PRIORITY + 2 )
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135 /* Demo board specifics. */
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136 #define mainPUSH_BUTTON GPIO_PIN_4
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139 #define mainQUEUE_SIZE ( 3 )
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140 #define mainDEBOUNCE_DELAY ( ( TickType_t ) 150 / portTICK_PERIOD_MS )
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141 #define mainNO_DELAY ( ( TickType_t ) 0 )
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143 * Configure the processor and peripherals for this demo.
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145 static void prvSetupHardware( void );
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148 * The 'check' task, as described at the top of this file.
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150 static void vCheckTask( void *pvParameters );
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153 * The task that is woken by the ISR that processes GPIO interrupts originating
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154 * from the push button.
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156 static void vButtonHandlerTask( void *pvParameters );
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159 * The task that controls access to the LCD.
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161 static void vPrintTask( void *pvParameter );
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163 /* String that is transmitted on the UART. */
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164 static char *cMessage = "Task woken by button interrupt! --- ";
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165 static volatile char *pcNextChar;
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167 /* The semaphore used to wake the button handler task from within the GPIO
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168 interrupt handler. */
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169 SemaphoreHandle_t xButtonSemaphore;
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171 /* The queue used to send strings to the print task for display on the LCD. */
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172 QueueHandle_t xPrintQueue;
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174 /* Newer library version. */
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175 extern void UARTConfigSetExpClk(unsigned long ulBase, unsigned long ulUARTClk, unsigned long ulBaud, unsigned long ulConfig);
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176 /*-----------------------------------------------------------*/
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180 /* Configure the clocks, UART and GPIO. */
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181 prvSetupHardware();
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183 /* Create the semaphore used to wake the button handler task from the GPIO
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185 vSemaphoreCreateBinary( xButtonSemaphore );
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186 xSemaphoreTake( xButtonSemaphore, 0 );
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188 /* Create the queue used to pass message to vPrintTask. */
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189 xPrintQueue = xQueueCreate( mainQUEUE_SIZE, sizeof( char * ) );
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191 /* Start the standard demo tasks. */
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192 vStartIntegerMathTasks( tskIDLE_PRIORITY );
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193 vStartPolledQueueTasks( mainQUEUE_POLL_PRIORITY );
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194 vStartSemaphoreTasks( mainSEM_TEST_PRIORITY );
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195 vStartBlockingQueueTasks( mainBLOCK_Q_PRIORITY );
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197 /* Start the tasks defined within the file. */
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198 xTaskCreate( vCheckTask, "Check", configMINIMAL_STACK_SIZE, NULL, mainCHECK_TASK_PRIORITY, NULL );
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199 xTaskCreate( vButtonHandlerTask, "Status", configMINIMAL_STACK_SIZE, NULL, mainCHECK_TASK_PRIORITY + 1, NULL );
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200 xTaskCreate( vPrintTask, "Print", configMINIMAL_STACK_SIZE, NULL, mainCHECK_TASK_PRIORITY - 1, NULL );
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202 /* Start the scheduler. */
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203 vTaskStartScheduler();
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205 /* Will only get here if there was insufficient heap to start the
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210 /*-----------------------------------------------------------*/
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212 static void vCheckTask( void *pvParameters )
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214 portBASE_TYPE xErrorOccurred = pdFALSE;
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215 TickType_t xLastExecutionTime;
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216 const char *pcPassMessage = "PASS";
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217 const char *pcFailMessage = "FAIL";
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219 /* Initialise xLastExecutionTime so the first call to vTaskDelayUntil()
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220 works correctly. */
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221 xLastExecutionTime = xTaskGetTickCount();
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225 /* Perform this check every mainCHECK_DELAY milliseconds. */
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226 vTaskDelayUntil( &xLastExecutionTime, mainCHECK_DELAY );
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228 /* Has an error been found in any task? */
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230 if( xAreIntegerMathsTaskStillRunning() != pdTRUE )
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232 xErrorOccurred = pdTRUE;
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235 if( xArePollingQueuesStillRunning() != pdTRUE )
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237 xErrorOccurred = pdTRUE;
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240 if( xAreSemaphoreTasksStillRunning() != pdTRUE )
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242 xErrorOccurred = pdTRUE;
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245 if( xAreBlockingQueuesStillRunning() != pdTRUE )
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247 xErrorOccurred = pdTRUE;
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250 /* Send either a pass or fail message. If an error is found it is
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251 never cleared again. We do not write directly to the LCD, but instead
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252 queue a message for display by the print task. */
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253 if( xErrorOccurred == pdTRUE )
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255 xQueueSend( xPrintQueue, &pcFailMessage, portMAX_DELAY );
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259 xQueueSend( xPrintQueue, &pcPassMessage, portMAX_DELAY );
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263 /*-----------------------------------------------------------*/
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265 static void prvSetupHardware( void )
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267 /* Setup the PLL. */
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268 SysCtlClockSet( SYSCTL_SYSDIV_10 | SYSCTL_USE_PLL | SYSCTL_OSC_MAIN | SYSCTL_XTAL_6MHZ );
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270 /* Setup the push button. */
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271 SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOC);
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272 GPIODirModeSet(GPIO_PORTC_BASE, mainPUSH_BUTTON, GPIO_DIR_MODE_IN);
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273 GPIOIntTypeSet( GPIO_PORTC_BASE, mainPUSH_BUTTON,GPIO_FALLING_EDGE );
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274 IntPrioritySet( INT_GPIOC, configKERNEL_INTERRUPT_PRIORITY );
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275 GPIOPinIntEnable( GPIO_PORTC_BASE, mainPUSH_BUTTON );
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276 IntEnable( INT_GPIOC );
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280 /* Enable the UART. */
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281 SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0);
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282 SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);
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284 /* Set GPIO A0 and A1 as peripheral function. They are used to output the
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286 GPIODirModeSet( GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PIN_1, GPIO_DIR_MODE_HW );
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288 /* Configure the UART for 8-N-1 operation. */
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289 UARTConfigSetExpClk( UART0_BASE, SysCtlClockGet(), mainBAUD_RATE, UART_CONFIG_WLEN_8 | UART_CONFIG_PAR_NONE | UART_CONFIG_STOP_ONE );
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291 /* We don't want to use the fifo. This is for test purposes to generate
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292 as many interrupts as possible. */
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293 HWREG( UART0_BASE + UART_O_LCR_H ) &= ~mainFIFO_SET;
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295 /* Enable Tx interrupts. */
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296 HWREG( UART0_BASE + UART_O_IM ) |= UART_INT_TX;
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297 IntPrioritySet( INT_UART0, configKERNEL_INTERRUPT_PRIORITY );
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298 IntEnable( INT_UART0 );
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301 /* Initialise the LCD> */
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302 OSRAMInit( false );
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303 OSRAMStringDraw("www.FreeRTOS.org", 0, 0);
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304 OSRAMStringDraw("LM3S811 demo", 16, 1);
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306 /*-----------------------------------------------------------*/
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308 static void vButtonHandlerTask( void *pvParameters )
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310 const char *pcInterruptMessage = "Int";
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314 /* Wait for a GPIO interrupt to wake this task. */
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315 while( xSemaphoreTake( xButtonSemaphore, portMAX_DELAY ) != pdPASS );
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317 /* Start the Tx of the message on the UART. */
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318 UARTIntDisable( UART0_BASE, UART_INT_TX );
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320 pcNextChar = cMessage;
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322 /* Send the first character. */
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323 if( !( HWREG( UART0_BASE + UART_O_FR ) & UART_FR_TXFF ) )
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325 HWREG( UART0_BASE + UART_O_DR ) = *pcNextChar;
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330 UARTIntEnable(UART0_BASE, UART_INT_TX);
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332 /* Queue a message for the print task to display on the LCD. */
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333 xQueueSend( xPrintQueue, &pcInterruptMessage, portMAX_DELAY );
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335 /* Make sure we don't process bounces. */
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336 vTaskDelay( mainDEBOUNCE_DELAY );
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337 xSemaphoreTake( xButtonSemaphore, mainNO_DELAY );
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341 /*-----------------------------------------------------------*/
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343 void vUART_ISR(void)
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345 unsigned long ulStatus;
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347 /* What caused the interrupt. */
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348 ulStatus = UARTIntStatus( UART0_BASE, pdTRUE );
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350 /* Clear the interrupt. */
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351 UARTIntClear( UART0_BASE, ulStatus );
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353 /* Was a Tx interrupt pending? */
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354 if( ulStatus & UART_INT_TX )
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356 /* Send the next character in the string. We are not using the FIFO. */
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357 if( *pcNextChar != NULL )
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359 if( !( HWREG( UART0_BASE + UART_O_FR ) & UART_FR_TXFF ) )
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361 HWREG( UART0_BASE + UART_O_DR ) = *pcNextChar;
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367 /*-----------------------------------------------------------*/
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369 void vGPIO_ISR( void )
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371 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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373 /* Clear the interrupt. */
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374 GPIOPinIntClear( GPIO_PORTC_BASE, mainPUSH_BUTTON );
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376 /* Wake the button handler task. */
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377 xSemaphoreGiveFromISR( xButtonSemaphore, &xHigherPriorityTaskWoken );
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378 portEND_SWITCHING_ISR( xHigherPriorityTaskWoken );
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380 /*-----------------------------------------------------------*/
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382 static void vPrintTask( void *pvParameters )
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385 unsigned portBASE_TYPE uxLine = 0, uxRow = 0;
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389 /* Wait for a message to arrive. */
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390 xQueueReceive( xPrintQueue, &pcMessage, portMAX_DELAY );
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392 /* Write the message to the LCD. */
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396 OSRAMStringDraw( pcMessage, uxLine & 0x3f, uxRow & 0x01);
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