serial.c

RT-Thread是发展中的下一代微内核嵌入式实时操作系统

/*
 * 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
 * 2006-03-13     Bernard      first version
 */

#include <rtthread.h>
#include <rthw.h>

#include "s3c4510.h"

#define	USTAT_RCV_READY         0x20   /* receive data ready */ 
#define	USTAT_TXB_EMPTY         0x40   /* tx buffer empty */

void rt_serial_init(void);

/**
 * @addtogroup S3C4510
 */
/*@{*/

/**
 * This function is used to display a string on console, normally, it's 
 * invoked by rt_kprintf
 *
 * @param str the displayed string
 */
void rt_console_puts(const char* str)
{
	while (*str) 
	{
		rt_serial_putc (*str++);
	}
}

/**
 * This function initializes serial
 */
void rt_serial_init()
{
	rt_uint32_t divisor = 0;

	divisor = 0x500; /* 19200 baudrate, 50MHz */

	UARTLCON0 = 0x03;
	UARTCONT0 = 0x09;
	UARTBRD0  = divisor;

	UARTLCON1 = 0x03;
	UARTCONT1 = 0x09;
	UARTBRD1  = divisor;

	for(divisor=0; divisor<100; divisor++);
}

/**
 * This function read a character from serial without interrupt enable mode 
 *
 * @return the read char
 */
char rt_serial_getc()
{
	while ((UARTSTAT0 & USTAT_RCV_READY) == 0);

	return UARTRXB0;
}

/**
 * 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)
{
	/*
		to be polite with serial console add a line feed
		to the carriage return character
	*/
	if (c=='\n')rt_serial_putc('\r');

	/* wait for room in the transmit FIFO */
	while(!(UARTSTAT0 & USTAT_TXB_EMPTY));

	UARTTXH0 = (rt_uint8_t)c;
}

/*@}*/