basiccan.c

来自「This library is Copyright (c) Raphael Zu」· C语言 代码 · 共 54 行

/***************************************************************************
                          basiccan.c  -  description
                             -------------------
    begin                : Fri May 17 2002
    copyright            : (C) 2002 by Raphael Zulliger
    email                : [e-mail]
 ***************************************************************************/

/***************************************************************************
 *                                                                         *
 *   This library is Copyright (c) Raphael Zulliger <[e-mail]>.       *
 *   It is licensed under the GNU Library General Public License (LGPL).   *
 *                                                                         *
 ***************************************************************************/


#include <def.h>
#include <general.h>
#include <objdict.h>
#include <canop.h>

BOOL readRxBuffer(void)
{
	// because arbracan AND the PIC-CAN-C-Lib can't start an interrupt when rx 
	// messages are in the queue, we have to poll reading... */
    Message rrb_m;
    BYTE rrb_i;
    BOOL returnValue = FALSE;
	
	// go through every buffer-field and check if the field is emtpy (see next if-condition)
	for( rrb_i=(BYTE)0x00; rrb_i<(BYTE)RX_CAN_BUFFER_SIZE; rrb_i++ )
	{
		if( canMessageRxBuffer[rrb_i].valid == FALSE )
		{	// now we've found an empty field, so check if there's a message in the 
			// can-receive buffer of the chip...
		    if( canReceive( (BYTE)0x00, &rrb_m ) == (BYTE)0x00 )   
    		{ // as long as data are in the queue and we have not tryed to fill more than available fields of
	    	  // the receive buffer...
				canMessageRxBuffer[rrb_i].m.len = rrb_m.len;
		        canMessageRxBuffer[rrb_i].m.rtr = rrb_m.rtr;
		        canMessageRxBuffer[rrb_i].m.cob_id.w = rrb_m.cob_id.w;
	        	memcpy( (void*)&canMessageRxBuffer[rrb_i].m.data[0], (void*)&rrb_m.data[0], rrb_m.len );
	    	    canMessageRxBuffer[rrb_i].valid = TRUE;
                returnValue = TRUE;
	        }
	        else
	        {	// there's no new message in the buffer, so we can leave this function
				return returnValue;
	        }
	    }
    }
    return returnValue;
}