.\"	$OpenBSD: hsq.4,v 1.1 1999/11/28 12:30:20 downsj Exp $
.\"
.\" Copyright (c) 1990, 1991 The Regents of the University of California.
.\" All rights reserved.
.\"
.\" This code is derived from software contributed to Berkeley by
.\" the Systems Programming Group of the University of Utah Computer
.\" Science Department.
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
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.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"	This product includes software developed by the University of
.\"	California, Berkeley and its contributors.
.\" 4. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\"     from: @(#)dca.4	5.2 (Berkeley) 3/27/91
.\"	from: Id: com.4,v 1.1 1993/08/06 11:19:07 cgd Exp
.\"
.Dd November 28, 1999
.Dt HSQ 4 i386
.Os
.Sh NAME
.Nm hsq
.Nd
multiplexing serial communications interface
.Sh SYNOPSIS
.Cd "hsq0 at isa? port 0x140 irq 10"
.Cd "com* at hsq? slave ?"
.Sh DESCRIPTION
The
.Nm hsq
driver provides support for boards that multiplex together up to four
.Tn EIA
.Tn RS-232C
.Pf ( Tn CCITT
.Tn V.28 )
communications interfaces.
.Pp
Each
.Nm
device is the master device for up to four
.Nm com
devices.  The kernel configuration specifies these
.Nm com
devices as slave devices of the
.Nm
device, as shown in the synopsis.  The slave ID given for each
.Nm com
device determines which bit in the interrupt multiplexing register is
tested to find interrupts for that device.
The
.Tn port
specification for the
.Nm
device is used to compute the base addresses for the
.Nm com
subdevices and the port for the interrupt multiplexing register.
.Sh FILES
.Bl -tag -width Pa
.It Pa /dev/tty0?
.El
.Sh SEE ALSO
.Xr com 4
.Sh HISTORY
The
.Nm
driver was written by Denis A. Doroshenko, based on the
.Xr ast 4
driver.