请问串口读取，如何设置延时

Question

读取串口时经常死在这句话了，
　　i=read(fd2,&rdata[recver_i],1);

请问串口读取，如何设置延时

我的相关程序

struct termios options;

bzero(&options, sizeof(options));

fd1=open(COM2,O_RDWR);  //comm 2

if (fd1==-1)
{
  printf("%s open false\n",dev);
  exit(0);
}
fcntl(fd1, F_SETFL, 0);
tcgetattr(fd1, &options);
cfsetispeed(&options, BAUDRATE_1);
cfsetospeed(&options, BAUDRATE_1);

options.c_cflag &= ~CSIZE;
options.c_cflag |= CS8;
options.c_cflag &= ~PARENB;
options.c_iflag &= ~INPCK;
options.c_cflag &= ~CSTOPB;

options.c_cflag |= CLOCAL | CREAD;

options.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG);

options.c_oflag &= ~OPOST;

options.c_iflag &= ~(BRKINT | ICRNL | INPCK | ISTRIP | IXON);

options.c_cc[VTIME] = 1; /* 设置超时1 seconds*/   
options.c_cc[VMIN] = 1; /* word and word time out, Update the options and do it NOW */

tcsetattr(fd1, TCSANOW, &options);

bzero(&options, sizeof(options));