flash.c

Show hou use semaphores in RTL-ARM

/* 
 ********************************************************************
 * Project:    GNU-Port FreeRTOS Port
 * File:    	flash.c
 *
 * System:   	ARM7TDMI-S 32 Bit (LPC2378)
 * Compiler:  	GCC 4.0.3
 *
 * Date:      	2006-11-17
 * Author:    	Grohmann
 *
 * Rights:    	Hitex Development Tools GmbH
 *            	Greschbachstr. 12
 *            	D-76229 Karlsruhe
 ********************************************************************
 * Description:
 *
 * This file is part of the GNU FreeRTOS Port
 * The code is based on the FreeRTOS originated by Richard Barry
 * This is a small implementation preemtive and semaphore task. 
 * The application runs in ARM mode with high optimization level.
 *	
 ********************************************************************
 * History:
 *
 *  Revision 1.0    2006/11/17      Gn
 *     Initial revision 
 ********************************************************************
 * This is a preliminary version.
 *
 * WARRANTY:  HITEX warrants that the media on which the SOFTWARE is 
 * furnished is free from defects in materials and workmanship under 
 * normal use and service for a period of ninety (90) days. HITEX entire
 * liability and your exclusive remedy shall be the replacement of the 
 * SOFTWARE if the media is defective. This Warranty is void if failure
 * of the media resulted from unauthorized modification, accident, abuse,
 * or misapplication.
 *
 * DISCLAIMER:  OTHER THAN THE ABOVE WARRANTY, THE SOFTWARE IS FURNISHED
 * "AS IS" WITHOUT WARRANTY OF ANY KIND. HITEX DISCLAIMS ALL OTHER WARRANTIES,
 * EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 *
 * NEITHER HITEX NOR ITS AFFILIATES SHALL BE LIABLE FOR ANY DAMAGES ARISING
 * OUT OF THE USE OF OR INABILITY TO USE THE SOFTWARE, INCLUDING DAMAGES FOR
 * LOSS OF PROFITS, BUSINESS INTERRUPTION, OR ANY SPECIAL, INCIDENTAL, INDIRECT
 * OR CONSEQUENTIAL DAMAGES EVEN IF HITEX HAS BEEN ADVISED OF THE POSSIBILITY 
 * OF SUCH DAMAGES.
 ********************************************************************/


/**
 * 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>
 */

#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 portCHAR * 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 );
	}
}