rt-thread/bsp/x86/drivers/serial.c

/*
 * File      : serial.c
 * This file is part of RT-Thread RTOS
 * COPYRIGHT (C) 2006, RT-Thread Development Team
 *
 * The license and distribution terms for this file may be
 * found in the file LICENSE in this distribution or at
 * http://openlab.rt-thread.com/license/LICENSE
 *
 * Change Logs:
 * Date           Author       Notes
 * 2006-09-15     QiuYi        the first version
 * 2006-10-10     Bernard      use keyboard instead of serial
 */
 
#include <rtthread.h>
#include <rthw.h>

#include <bsp.h>

/**
 * @addtogroup QEMU
 */
/*@{*/

/**
 * This function initializes serial
 */
void rt_serial_init(void)
{
	outb(COM1+3,0x80);	/* set DLAB of line control reg */
	outb(COM1,0x0c);	/* LS of divisor (48 -> 2400 bps */
	outb(COM1+1,0x00);	/* MS of divisor */
	outb(COM1+3,0x03);	/* reset DLAB */
	outb(COM1+4,0x0b);	/* set DTR,RTS, OUT_2 */
	outb(COM1+1,0x0d);	/* enable all intrs but writes */
	inb(COM1);			/* read data port to reset things (?) */
}

/**
 * This function read a character from serial without interrupt enable mode 
 *
 * @return the read char
 */
char rt_serial_getc(void)
{

	while(!(inb(COM1+COMSTATUS) & COMDATA));
	
	return inb(COM1+COMREAD);

}

/**
 * This function will write a character to serial without interrupt enable mode
 *
 * @param c the char to write
 */
void rt_serial_putc(const char c)
{
	int val;
	
	while(1)
	{
   		if ((val = inb(COM1+COMSTATUS)) & THRE) 
			break;
	}
	
	outb(COM1+COMWRITE, c&0xff);
}

/*@}*/