FreeRTOS-Kernel/Demo/Common/Full/flash.c

/*
    FreeRTOS V7.0.2 - Copyright (C) 2011 Real Time Engineers Ltd.
	

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    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 modification 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
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    or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
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*/


/**
 * Creates eight tasks, each of which flash an LED at a different rate.  The first 
 * LED flashes every 125ms, the second every 250ms, the third every 375ms, etc.
 *
 * The LED flash tasks provide instant visual feedback.  They show that the scheduler 
 * is still operational.
 *
 * The PC port uses the standard parallel port for outputs, the Flashlite 186 port 
 * uses IO port F.
 *
 * \page flashC flash.c
 * \ingroup DemoFiles
 * <HR>
 */

/*
Changes from V2.0.0

	+ Delay periods are now specified using variables and constants of
	  portTickType rather than unsigned long.

Changes from V2.1.1

	+ The stack size now uses configMINIMAL_STACK_SIZE.
	+ String constants made file scope to decrease stack depth on 8051 port.
*/

#include <stdlib.h>

/* Scheduler include files. */
#include "FreeRTOS.h"
#include "task.h"

/* Demo program include files. */
#include "partest.h"
#include "flash.h"
#include "print.h"

#define ledSTACK_SIZE		configMINIMAL_STACK_SIZE

/* Structure used to pass parameters to the LED tasks. */
typedef struct LED_PARAMETERS
{
	unsigned portBASE_TYPE uxLED;		/*< The output the task should use. */
	portTickType xFlashRate;	/*< The rate at which the LED should flash. */
} xLEDParameters;

/* The task that is created eight times - each time with a different xLEDParaemtes 
structure passed in as the parameter. */
static void vLEDFlashTask( void *pvParameters );

/* String to print if USE_STDIO is defined. */
const char * const pcTaskStartMsg = "LED flash task started.\r\n";

/*-----------------------------------------------------------*/

void vStartLEDFlashTasks( unsigned portBASE_TYPE uxPriority )
{
unsigned portBASE_TYPE uxLEDTask;
xLEDParameters *pxLEDParameters;
const unsigned portBASE_TYPE uxNumOfLEDs = 8;
const portTickType xFlashRate = 125;

	/* Create the eight tasks. */
	for( uxLEDTask = 0; uxLEDTask < uxNumOfLEDs; ++uxLEDTask )
	{
		/* Create and complete the structure used to pass parameters to the next 
		created task. */
		pxLEDParameters = ( xLEDParameters * ) pvPortMalloc( sizeof( xLEDParameters ) );
		pxLEDParameters->uxLED = uxLEDTask;
		pxLEDParameters->xFlashRate = ( xFlashRate + ( xFlashRate * ( portTickType ) uxLEDTask ) );
		pxLEDParameters->xFlashRate /= portTICK_RATE_MS;

		/* Spawn the task. */
		xTaskCreate( vLEDFlashTask, "LEDx", ledSTACK_SIZE, ( void * ) pxLEDParameters, uxPriority, ( xTaskHandle * ) NULL );
	}
}
/*-----------------------------------------------------------*/

static void vLEDFlashTask( void *pvParameters )
{
xLEDParameters *pxParameters;

	/* Queue a message for printing to say the task has started. */
	vPrintDisplayMessage( &pcTaskStartMsg );

	pxParameters = ( xLEDParameters * ) pvParameters;

	for(;;)
	{
		/* Delay for half the flash period then turn the LED on. */
		vTaskDelay( pxParameters->xFlashRate / ( portTickType ) 2 );
		vParTestToggleLED( pxParameters->uxLED );

		/* Delay for half the flash period then turn the LED off. */
		vTaskDelay( pxParameters->xFlashRate / ( portTickType ) 2 );
		vParTestToggleLED( pxParameters->uxLED );
	}
}