/*
 * This utility opens a serial port, asserts DTR for 50 ms, then negates it
 * and exits.  It is intended for use with FreeCalypso DUART28C adapters.
 */

#include <sys/types.h>
#include <sys/file.h>
#include <sys/ioctl.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

main(argc, argv)
	char **argv;
{
	int target_fd;
	int mctl_arg = TIOCM_DTR;

	if (argc != 2) {
		fprintf(stderr, "usage: %s ttyname\n", argv[0]);
		exit(1);
	}
	target_fd = open(argv[1], O_RDWR|O_NONBLOCK);
	if (target_fd < 0) {
		perror(argv[1]);
		exit(1);
	}
	ioctl(target_fd, TIOCMBIS, &mctl_arg);
	usleep(50000);
	ioctl(target_fd, TIOCMBIC, &mctl_arg);
	exit(0);
}