Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!clyde.concordia.ca!uunet!datapg!com50!pai!erc
From: erc@pai.UUCP (Eric Johnson)
Newsgroups: comp.unix.i386
Subject: Request for Help on Interactive COM2: access
Keywords: Interactive UNIX Serial COM2:
Message-ID: <793@pai.UUCP>
Date: 18 Dec 89 16:40:21 GMT
Organization: Prime Automation, Inc., Burnsville, MN
Lines: 127

I'm having some problems accessing the second serial port
under Interactive UNIX.  I have a no-name 386 clone with
two serial ports clearly marked on the back. I`m running
Interactive's 386/ix release 2.0 (release notes Dec 88).

COM1: works fine (I have a MS serial mouse clone hooked up to
it and the mouse works fine with the X Window System).

There are no getty's running on any serial ports (at least 
that's what /etc/inittab says).

What I want to do is access the second serial port through a C 
program, for my own serial I/O.  Since the first port is used by the
mouse, I need to use the second port.

Interactive's documentation seems to say that the asy driver comes
pre-installed and that it handles both COM1: and COM2:. None of the
kconfig/sysadm menus seem to want to give me any information 
regarding the serial ports.

When I try to open the port with a simple C program (source below),
I get error #6 (ENXIO in sys/errno.h): 

No such device or address.

The code looks like:

______________________________________________________________

/*
**	foo.c
**	Test program to open a port.
**
**	E F Johnson
**
*/

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

extern int	errno;

#define	BUFSIZE		256
#define	MY_PORT		"/dev/tty01"

main( argc, argv )

int	argc;
char	*argv[];

{
	int	port, i;
	char	error_message[ BUFSIZE + 1 ];
	char	dev_file[ BUFSIZE + 1 ];

	/*
	**	Check for -dev devicefile on command line
	*/
	strcpy( dev_file, MY_PORT );

	i = 1;
	while( i < argc )
		{
		if ( strcmp( "-dev", argv[ i ] ) == 0 )
			{
			i++;
			if ( i < argc )
				{
				strcpy( dev_file, argv[ i ] );
				}
			}
		i++;
		}


	port = open( dev_file, O_RDWR + O_NDELAY );

	if ( port == (-1) )
		{
		sprintf( error_message, "ERROR %d: Could not open %s.",
			errno, dev_file );
		
		perror( error_message );
		}
	else
		{
		close( port );
		printf( "Port %s opened successfully\n", dev_file );
		}
	exit( 0 );

}


/*
**	end of file.
*/

______________________________________________________________

Am I doing anything wrong in the software?  This same program
opens /dev/tty00 (COM1:) just fine.

Should I tear open the machine and check the hardware switch settings?
Perhaps this indicates that the COM2: is not set up properly 
in hardware?

The documentation seems to indicate that the device file mapping is:
COM1:	/dev/tty00
COM2:	/dev/tty01

Is this correct?
Is there anywhere else I should check?  (Section 11.10 Adding a New Terminal
in the 386/ix Operating System Guide doesn't really seem to help.)

Does anyone have any ideas?  Any help would be appreciated.

Thanks, 
-Eric

-- 
Eric F. Johnson, Boulware Technologies, Inc. 
415 W. Travelers Trail, Burnsville, MN 55337 USA.  Phone: +1 612-894-0313. 
erc@pai.mn.org    - or -   bungia!pai!erc
(We have a very dumb mailer, so please send a bang-!-style return address.)