mcp2515_set_dyn_filter.c

Library for CAN Controler sja1000

// ----------------------------------------------------------------------------
/*
 * Copyright (c) 2007 Fabian Greif, Roboterclub Aachen e.V.
 *  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * $Id: mcp2515_set_dyn_filter.c 6837 2008-11-16 19:05:15Z fabian $
 */
// ----------------------------------------------------------------------------

#include "mcp2515_private.h"
#ifdef	SUPPORT_FOR_MCP2515__

#include <util/delay.h>

// ----------------------------------------------------------------------------
// set a filter

bool mcp2515_set_filter(uint8_t number, const can_filter_t *filter)
{
	uint8_t mask_address = 0;
	uint8_t mode = mcp2515_read_register(CANSTAT);
	
	if (number > 5)
		return false;
	
	// change to configuration mode
	mcp2515_change_operation_mode( (1<<REQOP2) );
	
	// set filter mask
	if (number == 0)
	{
		mask_address = RXM0SIDH;
		
		#if SUPPORT_EXTENDED_CANID
			if (filter->flags.extended == 0x3) {
				// only extended identifier
				mcp2515_write_register(RXB0CTRL, (1<<RXM1));
			}
			else if (filter->flags.extended == 0x2) {
				// only standard identifier
				mcp2515_write_register(RXB0CTRL, (1<<RXM0));
			}
			else {
				// receive all messages
				mcp2515_write_register(RXB0CTRL, 0);
			}
		#else
			// Buffer 0: Empfangen aller Nachrichten mit Standard Identifier 
			// die den Filter Kriterien gengen
			mcp2515_write_register(RXB0CTRL, (1<<RXM0));
		#endif
	}
	else if (number == 2)
	{
		mask_address = RXM1SIDH;
		
		#if SUPPORT_EXTENDED_CANID
			if (filter->flags.extended == 0x3) {
				// only extended identifier
				mcp2515_write_register(RXB1CTRL, (1<<RXM1));
			}
			else if (filter->flags.extended == 0x2) {
				// only standard identifier
				mcp2515_write_register(RXB1CTRL, (1<<RXM0));
			}
			else {
				mcp2515_write_register(RXB1CTRL, 0);
			}
		#else
			// Buffer 1: Empfangen aller Nachrichten mit Standard Identifier 
			// die den Filter Kriterien gengen
			mcp2515_write_register(RXB1CTRL, (1<<RXM0));
		#endif
	}
	
	if (mask_address)
	{
		RESET(MCP2515_CS);
		spi_putc(SPI_WRITE);
		spi_putc(mask_address);
		#if SUPPORT_EXTENDED_CANID
			mcp2515_write_id(&filter->mask, (filter->flags.extended == 0x2) ? 0 : 1);
		#else
			mcp2515_write_id(&filter->mask);
		#endif
		SET(MCP2515_CS);
		
		_delay_us(1);
	}
	
	// write filter
	uint8_t filter_address;
	if (number >= 3) {
		number -= 3;
		filter_address = RXF3SIDH;
	}
	else {
		filter_address = RXF0SIDH;
	}
	
	RESET(MCP2515_CS);
	spi_putc(SPI_WRITE);
	spi_putc(filter_address | (number * 4));
	#if SUPPORT_EXTENDED_CANID
		mcp2515_write_id(&filter->id, (filter->flags.extended == 0x2) ? 0 : 1);
	#else
		mcp2515_write_id(&filter->id);
	#endif
	SET(MCP2515_CS);
	
	_delay_us(1);
	
	// restore previous mode
	mcp2515_change_operation_mode( mode );
	
	return true;
}

#endif	// SUPPORT_FOR_MCP2515__