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

67 lines
1.3 KiB
C

/*
* Copyright (c) 2006-2018, RT-Thread Development Team
*
* SPDX-License-Identifier: Apache-2.0
*
* 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);
}
/*@}*/