startup.c

开源实时操作系统

/*
	FreeRTOS.org V4.2.0 - Copyright (C) 2003-2007 Richard Barry.

	This file is part of the FreeRTOS.org distribution.

	FreeRTOS.org is free software; you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation; either version 2 of the License, or
	(at your option) any later version.

	FreeRTOS.org is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with FreeRTOS.org; if not, write to the Free Software
	Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

	A special exception to the GPL can be applied should you wish to distribute
	a combined work that includes FreeRTOS.org, without being obliged to provide
	the source code for any proprietary components.  See the licensing section 
	of http://www.FreeRTOS.org for full details of how and when the exception
	can be applied.

	***************************************************************************
	See http://www.FreeRTOS.org for documentation, latest information, license 
	and contact details.  Please ensure to read the configuration and relevant 
	port sections of the online documentation.
	***************************************************************************
*/


/*
 * startup.c
 * Author Jefferson L Smith, Robotronics Inc.
 *
 * __premain() is the startup code to init hardware and ram to execute the
 *             C application.
 *
 */

#include <sys/ports.h>
#include "cpu.h"

void ATTR_NEAR __premain (void);

void
__premain (void)
{
	// in case special mode enabled, avoid conflict on PORTE
	PEAR |= NECLK;
	// bgnd mode stops COP and RTI clocks
	COPCTL = RSBCK;
	// stops TCNT counter when debugging stops
	TSCR1 |= (1<<5);			// TFRZ
	
	// PLL
	CLKSEL = 0;				// disable PLL to configure
	// xtal 16MHz, bus 24MHz
	SYNR  = 3 - 1;
	REFDV = 2 - 1;
	while (!(CRGFLG & 0x08))    // wait for PLL LOCK
	cop_optional_reset();
	CLKSEL |= 0x80;             // use PLL

	// init switch inputs
	PERH = 0xff;				// pullups

	// outputs
#if PORT_LED==M6811_PORTB		//PORTB
	DDRB = 0xff;	// init LED
#elif PORT_LED==M6811_PORTA		//PORTA
	DDRA = 0xff;
#elif PORT_LED==M6811_PTT	//PTT
	DDRT = 0xff;
#elif PORT_LED==M6811_PTM	//PTM
	DDRM = 0xff;
#elif PORT_LED==M6811_PTP	//PTP
	DDRP = 0xff;
#elif PORT_LED==M6811_PTH	//PTH
	DDRH = 0xff;
#endif
	
}