嵌入式串口编程问题
新手求各位大牛指点！
PC串口和TQ2440开发板进行串口通信：
问题描述：程序运行后PC串口助手可以接收到开发板发来的数据并显示，然后我在PC串口助手手动发送数据到开发板，开发板无法接收数据！且此时串口助手内会显示一堆不知道哪来的数据。
测试控制台显示如下：
[root@EmbedGateway /work]# ./commTest
openttyS0.....
fcntl=0
isattysuccess!
fd-open=3
set done!
fd=3
write success!nwrite=6
Send data:ef ef ea 01 01 00
nread=0,read failure!
nread=0,read failure!
^C
[root@EmbedGateway /work]#
代码如下：
-------------------------------------------------

#include<stdio.h>

#include<string.h>

#include<sys/types.h>

#include<errno.h>

#include<sys/stat.h>

#include<fcntl.h>

#include<unistd.h>

#include<termios.h>

#include<stdlib.h>

	

int set_opt(int fd,int nSpeed,int nBits,char nEvent,int nStop){

	struct termios newtio,oldtio;

	if(tcgetattr(fd,&oldtio)!=0)

	{

		perror("SetupSerial1");

		return-1;

	}

	bzero(&newtio,sizeof(newtio));

	newtio.c_cflag|=CLOCAL|CREAD;

	newtio.c_cflag&=~CSIZE;

	switch(nBits)

	{

		case 7:newtio.c_cflag|=CS7;break;

		case 8:newtio.c_cflag|=CS8;break;

	}

	switch(nEvent)

	{

		case 'O':	newtio.c_cflag|=PARENB;

			     	newtio.c_cflag|=PARODD;

			     	newtio.c_iflag|=(INPCK|ISTRIP);

				break;

		case 'E':	newtio.c_iflag|=(INPCK|ISTRIP);

				newtio.c_cflag|=PARENB;

				newtio.c_cflag&=~PARODD;

				break;

		case 'N':	newtio.c_cflag&=~PARENB;

				break;

	}

	switch(nSpeed)

	{

		case 2400:

				cfsetispeed(&newtio,B2400);

				cfsetospeed(&newtio,B2400);

				break;

		case 4800:

				cfsetispeed(&newtio,B4800);

				cfsetospeed(&newtio,B4800);

				break;

		case 9600:

				cfsetispeed(&newtio,B9600);

				cfsetospeed(&newtio,B9600);

				break;

		case 115200:

				cfsetispeed(&newtio,B115200);

				cfsetospeed(&newtio,B115200);

				break;

		default:

				cfsetispeed(&newtio,B9600);

				cfsetospeed(&newtio,B9600);

				break;

	}

			

	if(nStop==1)

		newtio.c_cflag&=~CSTOPB;

	else if(nStop==2)

		newtio.c_cflag|=CSTOPB;

		

	newtio.c_cc[VTIME]=0;

	newtio.c_cc[VMIN]=0;

	tcflush(fd,TCIFLUSH);

			

	if((tcsetattr(fd,TCSANOW,&newtio))!=0)

	{

		perror("comset error");

		return-1;

	}

	printf("set done!\n");

	return 0;

}



int open_port(int fd,int comport)

{

	char*dev[]={"/dev/tq2440_serial0","/dev/tq2440_serial1","/dev/tq2440_serial2"};

	if(comport==1)

	{

		fd=open("/dev/tq2440_serial0",O_RDWR|O_NOCTTY|O_NDELAY);

		if(-1==fd)

		{

			perror("Can'tOpenSerialPort");

			return(-1);

		}else

			printf("openttyS0.....\n");}

	else if(comport==2)

	{

		fd=open("/dev/tq2440_serial1",O_RDWR|O_NOCTTY|O_NDELAY);

		if(-1==fd)

		{

			perror("Can'tOpenSerialPort");

			return(-1);

		}else

			printf("openttyS1.....\n");

	}

	else if(comport==3)

	{

		fd=open("/dev/tq2440_serial2",O_RDWR|O_NOCTTY|O_NDELAY);

		if(-1==fd)

		{

			perror("Can'tOpenSerialPort");

			return(-1);

		}else

			printf("openttyS2.....\n");

	}

	

	if(fcntl(fd,F_SETFL,0)<0)

		printf("fcntl failed!\n");

	e