Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!tut.cis.ohio-state.edu!ucbvax!hplabs!hpfcdc!hpfinote!pej
From: pej@hpfinote.HP.COM (Phil Jensen)
Newsgroups: comp.sys.hp
Subject: Re: Need help setting up RS-232 port
Message-ID: <15480004@hpfinote.HP.COM>
Date: 3 Jun 89 12:57:55 GMT
References: <8490001@weycord.WEYCO.COM>
Organization: Hewlett Packard CICD
Lines: 66

> I have what is probably a simple question but have not been
> able to find a simple answer to it.  I have an HP9000/370 with
> the HP-UX 6.5 operating system.  I simply need to open an
> RS-232 port and send/receive ASCII data.  Nothing complicated. I'm
> just going to use the port to talk with an analog mux.  I've got the
> RS-232 expander cards to do the job on the system.  I just need to 
> figure out how to do the job from a software standpoint.  Any assistance
> would be welcome.  Thanks in advance.
----------

The following should do what you need . Hope it helps .

*************************************************************************

#include <stdio.h>
#include <fcntl.h>
#include <termio.h>

#define BUFFER_SIZE 256
extern	int	errno;

main()
{
	int		tty;
	unsigned char 	buffer[BUFFER_SIZE];
	struct termio   term;

	/* open device as read / write 	 see mknod to make /dev/tty 	*/
	/* mknod /dev/tty c 1 0xscpp04 					*/
	/*       sc = select code      					*/
	/*       pp = port number for mux (98642) 00 for others   	*/

	if((tty = open("/dev/tty",O_RDWR)) < 1){
		fprintf(stderr,"Could not open /dev/tty ERRNO: %d\n",errno);
		exit(1);
	   }


	/* set up appropriate values for baud rate etc 			*/
	/* execute "man termio" for details 				*/

	term.c_oflag = OPOST;
	term.c_iflag = IGNBRK;
	term.c_lflag = 0;
	term.c_cflag = B2400|CSIZE|CS8|CREAD|CLOCAL;
	if(ioctl(tty,TCSETA,&term) == -1) {
		fprintf(stderr,"could not set /dev/tty\n");
		close(tty);
		exit(0);
	   }


	/* get BUFFER_SIZE bytes in character(byte) buffer 		*/

	read(tty,buffer,BUFFER_SIZE);


	/* write buffer to device 					*/

	write(tty,buffer,BUFFER_SIZE);

	
	/* close device 						*/

	close(tty);
}