debug.c

针对at91系列的arm的启动代码的编写有一个整体的说明

/* ----------------------------------------------------------------------------
 *         ATMEL Microcontroller Software Support  -  ROUSSET  -
 * ----------------------------------------------------------------------------
 * Copyright (c) 2006, Atmel Corporation

 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * - Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the disclaiimer below.
 *
 * - Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the disclaimer below in the documentation and/or
 * other materials provided with the distribution.
 *
 * Atmel's name may not be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * DISCLAIMER: THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE
 * DISCLAIMED. IN NO EVENT SHALL ATMEL 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.
 * ----------------------------------------------------------------------------
 * File Name           : debug.c
 * Object              :
 * Creation            : ODi Apr 19th 2006
 *-----------------------------------------------------------------------------
 */
#include "../include/part.h"
#include "../include/main.h"

#ifdef CFG_DEBUG

/* Write DBGU register */
static inline void write_dbgu(unsigned int offset, const unsigned int value)
{
	writel(value, offset + AT91C_BASE_DBGU);
}

/* Read DBGU registers */
static inline unsigned int read_dbgu( unsigned int offset)
{
	return readl(offset + AT91C_BASE_DBGU);
}


//*----------------------------------------------------------------------------
//* \fn    dbg_init
//* \brief This function is used to configure the DBGU COM port
//*----------------------------------------------------------------------------*/
void dbg_init(unsigned int baudrate)
{
	/* Disable interrupts */
	write_dbgu(US_IDR, -1);
	/* Reset the receiver and transmitter */
	write_dbgu(US_CR, AT91C_US_RSTRX | AT91C_US_RSTTX | AT91C_US_RXDIS  | AT91C_US_TXDIS);
	/* Configure the baudrate */
	write_dbgu(US_BRGR, baudrate);
	/* Configure USART in Asynchronous mode */
	write_dbgu(US_MR, AT91C_US_PAR);
	/* Enable RX and Tx */
	write_dbgu(US_CR, AT91C_US_RXEN | AT91C_US_TXEN);
}

//*----------------------------------------------------------------------------
//* \fn    dbg_print
//* \brief This function is used to configure the DBGU
//*----------------------------------------------------------------------------*/
void dbg_print(const char *ptr)
{
	int i=0;

	while (ptr[i] != '\0') {
		while ( !(read_dbgu(DBGU_CSR) & AT91C_US_TXRDY) );
		write_dbgu(DBGU_THR, ptr[i]);
		i++;
	}
}

#endif /* CFG_DEBUG */