enable hardware flow control

fpgautils.c

@@ -398,6 +398,7 @@ int serial_open(const char *devpath, unsigned long baud, signed short timeout, b
 
 	my_termios.c_cflag |= CS8;
 	my_termios.c_cflag |= CREAD;
+	my_termios.c_cflag |= CRTSCTS;
 	my_termios.c_cflag |= CLOCAL;
 	my_termios.c_cflag &= ~(CSIZE | PARENB);