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/*
* FreeRTOS Kernel V10.3.0
* Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
* the Software, and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
* http://www.FreeRTOS.org
* http://aws.amazon.com/freertos
*
* 1 tab == 4 spaces!
*/
/*
* 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_PERIOD_MS )
/* The semaphore used to synchronise the button push task with the interrupt. */
static SemaphoreHandle_t 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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