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387 lines
14 KiB
C
387 lines
14 KiB
C
/*
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FreeRTOS V6.1.1 - Copyright (C) 2011 Real Time Engineers Ltd.
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***************************************************************************
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* *
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* If you are: *
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* *
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* + New to FreeRTOS, *
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* + Wanting to learn FreeRTOS or multitasking in general quickly *
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* + Looking for basic training, *
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* + Wanting to improve your FreeRTOS skills and productivity *
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* *
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* then take a look at the FreeRTOS books - available as PDF or paperback *
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* *
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* "Using the FreeRTOS Real Time Kernel - a Practical Guide" *
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* http://www.FreeRTOS.org/Documentation *
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* *
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* A pdf reference manual is also available. Both are usually delivered *
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* to your inbox within 20 minutes to two hours when purchased between 8am *
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* and 8pm GMT (although please allow up to 24 hours in case of *
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* exceptional circumstances). Thank you for your support! *
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* *
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***************************************************************************
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This file is part of the FreeRTOS distribution.
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FreeRTOS is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License (version 2) as published by the
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Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
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***NOTE*** The exception to the GPL is included to allow you to distribute
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a combined work that includes FreeRTOS without being obliged to provide the
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source code for proprietary components outside of the FreeRTOS kernel.
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FreeRTOS is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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more details. You should have received a copy of the GNU General Public
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License and the FreeRTOS license exception along with FreeRTOS; if not it
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can be viewed here: http://www.freertos.org/a00114.html and also obtained
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by writing to Richard Barry, contact details for whom are available on the
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FreeRTOS WEB site.
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1 tab == 4 spaces!
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http://www.FreeRTOS.org - Documentation, latest information, license and
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contact details.
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http://www.SafeRTOS.com - A version that is certified for use in safety
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critical systems.
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http://www.OpenRTOS.com - Commercial support, development, porting,
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licensing and training services.
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*/
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/*
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* This project contains an application demonstrating the use of the
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* FreeRTOS.org mini real time scheduler on the Luminary Micro LM3S811 Eval
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* board. See http://www.FreeRTOS.org for more information.
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*
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* main() simply sets up the hardware, creates all the demo application tasks,
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* then starts the scheduler. http://www.freertos.org/a00102.html provides
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* more information on the standard demo tasks.
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*
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* In addition to a subset of the standard demo application tasks, main.c also
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* defines the following tasks:
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*
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* + A 'Print' task. The print task is the only task permitted to access the
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* LCD - thus ensuring mutual exclusion and consistent access to the resource.
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* Other tasks do not access the LCD directly, but instead send the text they
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* wish to display to the print task. The print task spends most of its time
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* blocked - only waking when a message is queued for display.
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*
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* + A 'Button handler' task. The eval board contains a user push button that
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* is configured to generate interrupts. The interrupt handler uses a
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* semaphore to wake the button handler task - demonstrating how the priority
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* mechanism can be used to defer interrupt processing to the task level. The
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* button handler task sends a message both to the LCD (via the print task) and
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* the UART where it can be viewed using a dumb terminal (via the UART to USB
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* converter on the eval board). NOTES: The dumb terminal must be closed in
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* order to reflash the microcontroller. A very basic interrupt driven UART
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* driver is used that does not use the FIFO. 19200 baud is used.
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*
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* + A 'check' task. The check task only executes every five seconds but has a
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* high priority so is guaranteed to get processor time. Its function is to
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* check that all the other tasks are still operational and that no errors have
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* been detected at any time. If no errors have every been detected 'PASS' is
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* written to the display (via the print task) - if an error has ever been
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* detected the message is changed to 'FAIL'. The position of the message is
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* changed for each write.
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*/
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/* Environment includes. */
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#include "DriverLib.h"
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/* Scheduler includes. */
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#include "FreeRTOS.h"
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#include "task.h"
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#include "queue.h"
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#include "semphr.h"
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/* Demo app includes. */
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#include "integer.h"
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#include "PollQ.h"
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#include "semtest.h"
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#include "BlockQ.h"
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/* Delay between cycles of the 'check' task. */
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#define mainCHECK_DELAY ( ( portTickType ) 5000 / portTICK_RATE_MS )
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/* UART configuration - note this does not use the FIFO so is not very
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efficient. */
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#define mainBAUD_RATE ( 19200 )
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#define mainFIFO_SET ( 0x10 )
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/* Demo task priorities. */
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#define mainQUEUE_POLL_PRIORITY ( tskIDLE_PRIORITY + 2 )
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#define mainCHECK_TASK_PRIORITY ( tskIDLE_PRIORITY + 3 )
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#define mainSEM_TEST_PRIORITY ( tskIDLE_PRIORITY + 1 )
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#define mainBLOCK_Q_PRIORITY ( tskIDLE_PRIORITY + 2 )
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/* Demo board specifics. */
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#define mainPUSH_BUTTON GPIO_PIN_4
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/* Misc. */
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#define mainQUEUE_SIZE ( 3 )
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#define mainDEBOUNCE_DELAY ( ( portTickType ) 150 / portTICK_RATE_MS )
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#define mainNO_DELAY ( ( portTickType ) 0 )
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/*
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* Configure the processor and peripherals for this demo.
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*/
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static void prvSetupHardware( void );
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/*
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* The 'check' task, as described at the top of this file.
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*/
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static void vCheckTask( void *pvParameters );
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/*
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* The task that is woken by the ISR that processes GPIO interrupts originating
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* from the push button.
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*/
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static void vButtonHandlerTask( void *pvParameters );
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/*
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* The task that controls access to the LCD.
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*/
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static void vPrintTask( void *pvParameter );
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/* String that is transmitted on the UART. */
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static portCHAR *cMessage = "Task woken by button interrupt! --- ";
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static volatile portCHAR *pcNextChar;
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/* The semaphore used to wake the button handler task from within the GPIO
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interrupt handler. */
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xSemaphoreHandle xButtonSemaphore;
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/* The queue used to send strings to the print task for display on the LCD. */
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xQueueHandle xPrintQueue;
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/*-----------------------------------------------------------*/
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int main( void )
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{
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/* Configure the clocks, UART and GPIO. */
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prvSetupHardware();
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/* Create the semaphore used to wake the button handler task from the GPIO
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ISR. */
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vSemaphoreCreateBinary( xButtonSemaphore );
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xSemaphoreTake( xButtonSemaphore, 0 );
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/* Create the queue used to pass message to vPrintTask. */
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xPrintQueue = xQueueCreate( mainQUEUE_SIZE, sizeof( portCHAR * ) );
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/* Start the standard demo tasks. */
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vStartIntegerMathTasks( tskIDLE_PRIORITY );
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vStartPolledQueueTasks( mainQUEUE_POLL_PRIORITY );
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vStartSemaphoreTasks( mainSEM_TEST_PRIORITY );
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vStartBlockingQueueTasks( mainBLOCK_Q_PRIORITY );
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/* Start the tasks defined within the file. */
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xTaskCreate( vCheckTask, "Check", configMINIMAL_STACK_SIZE, NULL, mainCHECK_TASK_PRIORITY, NULL );
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xTaskCreate( vButtonHandlerTask, "Status", configMINIMAL_STACK_SIZE, NULL, mainCHECK_TASK_PRIORITY + 1, NULL );
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xTaskCreate( vPrintTask, "Print", configMINIMAL_STACK_SIZE, NULL, mainCHECK_TASK_PRIORITY - 1, NULL );
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/* Start the scheduler. */
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vTaskStartScheduler();
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/* Will only get here if there was insufficient heap to start the
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scheduler. */
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return 0;
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}
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/*-----------------------------------------------------------*/
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static void vCheckTask( void *pvParameters )
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{
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portBASE_TYPE xErrorOccurred = pdFALSE;
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portTickType xLastExecutionTime;
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const portCHAR *pcPassMessage = "PASS";
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const portCHAR *pcFailMessage = "FAIL";
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/* Initialise xLastExecutionTime so the first call to vTaskDelayUntil()
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works correctly. */
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xLastExecutionTime = xTaskGetTickCount();
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for( ;; )
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{
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/* Perform this check every mainCHECK_DELAY milliseconds. */
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vTaskDelayUntil( &xLastExecutionTime, mainCHECK_DELAY );
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/* Has an error been found in any task? */
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if( xAreIntegerMathsTaskStillRunning() != pdTRUE )
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{
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xErrorOccurred = pdTRUE;
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}
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if( xArePollingQueuesStillRunning() != pdTRUE )
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{
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xErrorOccurred = pdTRUE;
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}
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if( xAreSemaphoreTasksStillRunning() != pdTRUE )
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{
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xErrorOccurred = pdTRUE;
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}
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if( xAreBlockingQueuesStillRunning() != pdTRUE )
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{
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xErrorOccurred = pdTRUE;
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}
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/* Send either a pass or fail message. If an error is found it is
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never cleared again. We do not write directly to the LCD, but instead
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queue a message for display by the print task. */
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if( xErrorOccurred == pdTRUE )
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{
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xQueueSend( xPrintQueue, &pcFailMessage, portMAX_DELAY );
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}
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else
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{
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xQueueSend( xPrintQueue, &pcPassMessage, portMAX_DELAY );
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}
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}
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}
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/*-----------------------------------------------------------*/
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static void prvSetupHardware( void )
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{
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/* Setup the PLL. */
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SysCtlClockSet( SYSCTL_SYSDIV_10 | SYSCTL_USE_PLL | SYSCTL_OSC_MAIN | SYSCTL_XTAL_6MHZ );
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/* Setup the push button. */
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SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOC);
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GPIODirModeSet(GPIO_PORTC_BASE, mainPUSH_BUTTON, GPIO_DIR_MODE_IN);
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GPIOIntTypeSet( GPIO_PORTC_BASE, mainPUSH_BUTTON,GPIO_FALLING_EDGE );
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IntPrioritySet( INT_GPIOC, configKERNEL_INTERRUPT_PRIORITY );
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GPIOPinIntEnable( GPIO_PORTC_BASE, mainPUSH_BUTTON );
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IntEnable( INT_GPIOC );
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/* Enable the UART. */
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SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0);
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SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);
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/* Set GPIO A0 and A1 as peripheral function. They are used to output the
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UART signals. */
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GPIODirModeSet( GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PIN_1, GPIO_DIR_MODE_HW );
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/* Configure the UART for 8-N-1 operation. */
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UARTConfigSet( UART0_BASE, mainBAUD_RATE, UART_CONFIG_WLEN_8 | UART_CONFIG_PAR_NONE | UART_CONFIG_STOP_ONE );
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/* We don't want to use the fifo. This is for test purposes to generate
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as many interrupts as possible. */
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HWREG( UART0_BASE + UART_O_LCR_H ) &= ~mainFIFO_SET;
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/* Enable Tx interrupts. */
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HWREG( UART0_BASE + UART_O_IM ) |= UART_INT_TX;
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IntPrioritySet( INT_UART0, configKERNEL_INTERRUPT_PRIORITY );
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IntEnable( INT_UART0 );
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/* Initialise the LCD> */
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OSRAMInit( false );
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OSRAMStringDraw("www.FreeRTOS.org", 0, 0);
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OSRAMStringDraw("LM3S811 demo", 16, 1);
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}
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/*-----------------------------------------------------------*/
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static void vButtonHandlerTask( void *pvParameters )
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{
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const portCHAR *pcInterruptMessage = "Int";
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for( ;; )
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{
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/* Wait for a GPIO interrupt to wake this task. */
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while( xSemaphoreTake( xButtonSemaphore, portMAX_DELAY ) != pdPASS );
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/* Start the Tx of the message on the UART. */
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UARTIntDisable( UART0_BASE, UART_INT_TX );
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{
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pcNextChar = cMessage;
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/* Send the first character. */
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if( !( HWREG( UART0_BASE + UART_O_FR ) & UART_FR_TXFF ) )
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{
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HWREG( UART0_BASE + UART_O_DR ) = *pcNextChar;
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}
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pcNextChar++;
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}
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UARTIntEnable(UART0_BASE, UART_INT_TX);
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/* Queue a message for the print task to display on the LCD. */
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xQueueSend( xPrintQueue, &pcInterruptMessage, portMAX_DELAY );
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/* Make sure we don't process bounces. */
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vTaskDelay( mainDEBOUNCE_DELAY );
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xSemaphoreTake( xButtonSemaphore, mainNO_DELAY );
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}
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}
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/*-----------------------------------------------------------*/
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void vUART_ISR(void)
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{
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unsigned portLONG ulStatus;
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/* What caused the interrupt. */
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ulStatus = UARTIntStatus( UART0_BASE, pdTRUE );
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/* Clear the interrupt. */
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UARTIntClear( UART0_BASE, ulStatus );
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/* Was a Tx interrupt pending? */
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if( ulStatus & UART_INT_TX )
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{
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/* Send the next character in the string. We are not using the FIFO. */
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if( *pcNextChar != 0 )
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{
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if( !( HWREG( UART0_BASE + UART_O_FR ) & UART_FR_TXFF ) )
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{
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HWREG( UART0_BASE + UART_O_DR ) = *pcNextChar;
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}
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pcNextChar++;
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}
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}
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}
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/*-----------------------------------------------------------*/
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void vGPIO_ISR( void )
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{
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portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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/* Clear the interrupt. */
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GPIOPinIntClear(GPIO_PORTC_BASE, mainPUSH_BUTTON);
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/* Wake the button handler task. */
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xSemaphoreGiveFromISR( xButtonSemaphore, &xHigherPriorityTaskWoken );
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portEND_SWITCHING_ISR( xHigherPriorityTaskWoken );
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}
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/*-----------------------------------------------------------*/
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static void vPrintTask( void *pvParameters )
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{
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portCHAR *pcMessage;
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unsigned portBASE_TYPE uxLine = 0, uxRow = 0;
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for( ;; )
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{
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/* Wait for a message to arrive. */
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xQueueReceive( xPrintQueue, &pcMessage, portMAX_DELAY );
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/* Write the message to the LCD. */
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uxRow++;
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uxLine++;
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OSRAMClear();
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OSRAMStringDraw( pcMessage, uxLine & 0x3f, uxRow & 0x01);
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}
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}
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