#include <stdio.h>
#include <unistd.h> /*Unix标准函数定义*/
#include <sys/types.h> /**/
#include <sys/stat.h> /**/
#include <fcntl.h> /*文件控制定义*/
#include <termios.h> /*PPSIX终端控制定义*/
#include <errno.h> /*错误号定义*/
#include <stdlib.h>
#include <string.h>

int main()
{
int fd,readnum;
char *dev="/dev/ttyS0",recv[100];
struct termios opt,oldopt;

fd = open( dev, O_RDWR );

tcgetattr( fd,&oldopt);

tcgetattr( fd,&opt);
cfsetispeed(&opt, B9600);//9600
cfsetospeed(&opt, B9600);

opt.c_cflag &= ~PARENB; //N
opt.c_cflag &= ~INPCK;
opt.c_cflag &= ~CSTOPB;//1
opt.c_cflag &= ~CSIZE;
opt.c_cflag |= CS8; //8

opt.c_iflag &= ~(IXON | IXOFF | IXANY);

opt.c_cc[VTIME] = 0;
opt.c_cc[VMIN] = 0;

opt.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG); /*Input*/
opt.c_oflag &= ~OPOST; /*Output*/

tcflush(fd, TCIOFLUSH);
tcsetattr(fd, TCSANOW, &opt);

while(1)
{
bzero(recv,100);
while((readnum = read(fd,recv,100))>0)
{
printf("%s\n",recv);
}
}

tcflush(fd, TCIOFLUSH);
tcsetattr(fd, TCSANOW, &oldopt);
close(fd);
}