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[/] [openrisc/] [trunk/] [rtos/] [freertos-6.1.1/] [Demo/] [NEC_78K0R_IAR/] [ButtonTask.c] - Rev 613
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/* FreeRTOS V6.1.1 - Copyright (C) 2011 Real Time Engineers Ltd. *************************************************************************** * * * If you are: * * * * + New to FreeRTOS, * * + Wanting to learn FreeRTOS or multitasking in general quickly * * + Looking for basic training, * * + Wanting to improve your FreeRTOS skills and productivity * * * * then take a look at the FreeRTOS books - available as PDF or paperback * * * * "Using the FreeRTOS Real Time Kernel - a Practical Guide" * * http://www.FreeRTOS.org/Documentation * * * * A pdf reference manual is also available. Both are usually delivered * * to your inbox within 20 minutes to two hours when purchased between 8am * * and 8pm GMT (although please allow up to 24 hours in case of * * exceptional circumstances). Thank you for your support! * * * *************************************************************************** This file is part of the FreeRTOS distribution. FreeRTOS is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License (version 2) as published by the Free Software Foundation AND MODIFIED BY the FreeRTOS exception. ***NOTE*** The exception to the GPL is included to allow you to distribute a combined work that includes FreeRTOS without being obliged to provide the source code for proprietary components outside of the FreeRTOS kernel. FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License and the FreeRTOS license exception along with FreeRTOS; if not it can be viewed here: http://www.freertos.org/a00114.html and also obtained by writing to Richard Barry, contact details for whom are available on the FreeRTOS WEB site. 1 tab == 4 spaces! http://www.FreeRTOS.org - Documentation, latest information, license and contact details. http://www.SafeRTOS.com - A version that is certified for use in safety critical systems. http://www.OpenRTOS.com - Commercial support, development, porting, licensing and training services. */ /* * This file defines the button push task and ISR as described at the top of * main.c. The ISR is called from a wrapper function defined in ButtonISR.s26. */ /* Kernel includes. */ #include "FreeRTOS.h" #include "task.h" #include "semphr.h" /* The LED output used by the button push task. */ #define butLED1 P7_bit.no7 /* A short delay used for button debouncing. */ #define butDEBOUNCE_DELAY ( 200 / portTICK_RATE_MS ) /* The semaphore used to synchronise the button push task with the interrupt. */ static xSemaphoreHandle xButtonSemaphore; /* * The definition of the button task itself. See the comments at the top of * main.c. */ void vButtonTask( void *pvParameters ) { /* Ensure the semaphore is created before it gets used. */ vSemaphoreCreateBinary( xButtonSemaphore ); for( ;; ) { /* Block on the semaphore to wait for an interrupt event. The semaphore is 'given' from vButtonISRHandler() below. Using portMAX_DELAY as the block time will cause the task to block indefinitely provided INCLUDE_vTaskSuspend is set to 1 in FreeRTOSConfig.h. */ xSemaphoreTake( xButtonSemaphore, portMAX_DELAY ); /* The button must have been pushed for this line to be executed. Simply toggle the LED. */ butLED1 = !butLED1; /* Wait a short time then clear any pending button pushes as a crude method of debouncing the switch. xSemaphoreTake() uses a block time of zero this time so it returns immediately rather than waiting for the interrupt to occur. */ vTaskDelay( butDEBOUNCE_DELAY ); xSemaphoreTake( xButtonSemaphore, 0 ); } } /*-----------------------------------------------------------*/ /* * The C portion of the interrupt handler. Interrupts are triggered by pushing * the button on the target board. This interrupt can cause a context switch * so has an assembly file wrapper defined within ButtonISR.s26. */ void vButtonISRHandler( void ) { short sHigherPriorityTaskWoken = pdFALSE; /* 'Give' the semaphore to unblock the button task. */ xSemaphoreGiveFromISR( xButtonSemaphore, &sHigherPriorityTaskWoken ); /* If giving the semaphore unblocked a task, and the unblocked task has a priority that is higher than the currently running task, then sHigherPriorityTaskWoken will have been set to pdTRUE. Passing a pdTRUE value to portYIELD_FROM_ISR() will cause this interrupt to return directly to the higher priority unblocked task. */ portYIELD_FROM_ISR( sHigherPriorityTaskWoken ); } /*-----------------------------------------------------------*/
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