#include <stdio.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <unistd.h>
static int fd = -1;
int main(void)
{
  int i,out;
  out = 0xe0;
  fd = open("/dev/IO/0",O_RDWR);
  if(fd<0)
    {
	  printf("failed to open the device \n");
	}
  else
  printf("successed to open the device \n");
  while(1)
    {
	  ioctl(fd , out);
	  for(i=0;i<5000000;i++);
	  out=(out<<1) & 0xf0;  //注意，這里一定要加“& 0xf0”這一項，因為0xe0<<1后就變成了0x1c0，為了把那個1變成0而只獲取有用的四位，所以加“& 0xf0”這一項
	 // printf("out=%x \n",out);
       if(out!=0xe0) out|=0x10;
	 // printf("out=%x \n",out);
	  
    }
   close(fd);
   printf("end of test \n");
   return 0;	
}