print.c

Show hou use semaphores in RTL-ARM

/* 
 ********************************************************************
 * Project:    GNU-Port FreeRTOS Port
 * File:    	print.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.
 ********************************************************************/

/**
 * Manages a queue of strings that are waiting to be displayed.  This is used to 
 * ensure mutual exclusion of console output.
 *
 * A task wishing to display a message will call vPrintDisplayMessage (), with a 
 * pointer to the string as the parameter. The pointer is posted onto the 
 * xPrintQueue queue.
 *
 * The task spawned in main. c blocks on xPrintQueue.  When a message becomes 
 * available it calls pcPrintGetNextMessage () to obtain a pointer to the next 
 * string, then uses the functions defined in the portable layer FileIO. c to 
 * display the message.
 *
 * <b>NOTE:</b>
 * Using console IO can disrupt real time performance - depending on the port.  
 * Standard C IO routines are not designed for real time applications.  While 
 * standard IO is useful for demonstration and debugging an alternative method 
 * should be used if you actually require console IO as part of your application.
 *
 * \page PrintC print.c
 * \ingroup DemoFiles
 * <HR>
 */

/*
Changes from V2.0.0

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

#include <stdlib.h>

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

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

static xQueueHandle xPrintQueue;

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

void vPrintInitialise( void )
{
const unsigned portBASE_TYPE uxQueueSize = 20;

	/* Create the queue on which errors will be reported. */
	xPrintQueue = xQueueCreate( uxQueueSize, ( unsigned portBASE_TYPE ) sizeof( portCHAR * ) );
}
/*-----------------------------------------------------------*/

void vPrintDisplayMessage( const portCHAR * const * ppcMessageToSend )
{
	#ifdef USE_STDIO
		xQueueSend( xPrintQueue, ( void * ) ppcMessageToSend, ( portTickType ) 0 );
	#else
    	/* Stop warnings. */
		( void ) ppcMessageToSend;
	#endif
}
/*-----------------------------------------------------------*/

const portCHAR *pcPrintGetNextMessage( portTickType xPrintRate )
{
portCHAR *pcMessage;

	if( xQueueReceive( xPrintQueue, &pcMessage, xPrintRate ) == pdPASS )
	{
		return pcMessage;
	}
	else
	{
		return NULL;
	}
}