Linux下的串口通信

移植了一个简单的开发板与pC机的串口通信，代码如下
/*发送字符*/
#include<stdio.h>
#include<string.h>
#include<malloc.h>
#include<sys/types.h>
#include<sys/stat.h>
#include<fcntl.h>
#include<unistd.h>
#include<termios.h>
#define buffer_size 100
volatile fd;
int flag_close;
int open_serial(int k)
{
if(k==0)
{
fd=open("/dev/ttySAC0", O_NOCTTY |O_NONBLOCK);
perror("open /dev/ttySAC0");
}
else
{
fd=open("/dev/ttySAC1",O_RDWR);
perror("open /dec/ttySAC1");
}
if(fd==-1)
return -1;
else
return 0;

}
int main(int argc,char *argv[])
{
char sbuf[]={"hello\n"};
int retv,i;
struct termios opt;
int length=sizeof(sbuf);
open_serial(0);
printf("ready for sending data");
tcgetattr(fd,&opt);
tcflush(fd,TCIOFLUSH);
cfmakeraw(&opt);//设置终端属性
cfsetispeed(&opt,B115200);
cfsetospeed(&opt,B115200);
/*设置8位数据位*/
opt.c_cflag &=~CSIZE;
opt.c_cflag |=CS8;
/*设置奇偶校验*/
opt.c_cflag &=~PARENB;
opt.c_cflag &=~INPCK;
tcsetattr(fd,TCSANOW,&opt);
retv=write(fd,sbuf,length);//将数据写入终端不需要1位1位的写吗？
if(retv==-1)
{
perror("write");

}
printf("the number of char sent is %d\n",retv);
flag_close=close(fd);
if(flag_close==-1)
printf("close the device failur!\n");
return 0;
}
结果运行时显示错误为：open /dev/ttySAC0: No such file or directory
write: Bad file descriptor
ready for sending datathe number of char sent is -1
close the device failur!
初学，有没有人能耐心看一下，指导一下，谢谢！
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