#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>
int main(int argc, char **argv)
{
int fd;
char val;
fd = open("/dev/f403tech", O_RDWR);
if (fd < 0)
{
printf("Can't open /dev/f403tech\n");
}
read(fd, &val, 1);
write(fd, &val, 1);
return 0;
}