.\"	$OpenBSD: zs.4,v 1.4 2002/02/19 06:59:13 jason Exp $
.\"
.\" Copyright (c) 1998 The OpenBSD Project
.\" All rights reserved.
.\"
.\"
.Dd March 4, 1998
.Dt ZS 4 sparc64
.Os
.Sh NAME
.Nm zs
.Nd Zilog 8530 (ZSCC) serial communications driver
.Sh SYNOPSIS
.Cd "zs* at sbus? slot ? offset ?"
.Cd "zstty* at zs? channel ?"
.Cd "zskbd* at zs? channel ?
.Cd "wskbd* at zskbd? console ?"
.Sh DESCRIPTION
The
.Nm
is a Zilog 8530 serial interface chip used in SBus-based ULTRAsparc
.Tn Sun
workstations.
The Zilog 8530 provides two input/output channels per instance.
Most
.Tn Sun
workstations include two of these interfaces.
One of the interfaces is usually hardwired for use by the keyboard and mouse
attached to the workstation console.
The
.Nm zskbd
devices connect keyboard devices to the generic keyboard driver
.Nm wskbd .
The remaining additional
.Nm zs
interfaces provide RS-423
and RS-232 serial ports for general purpose use.
.Pp
The
.Nm
driver supports all of the standard
.Xr tty 4
ioctl calls.
The status of the DTR, RTS, CTS, and DCD signals can be queried with
TIOCMGET command, but, due to limitations in the hardware,
only the DTR and RTS signals can be modified with TIOCMSET, TIOCMBIC,
and TIOCMBIS
.Xr ioctl 2
commands.
.Sh BUGS
The
.Nm
driver now supports cua minor devices, but with this known deficiency
in the simultaneous outgoing/incoming aspect of the driver:
The first outgoing connection succeeds, but second and subsequent
connections fail, apparently due to a getty hang.
The hung getty apparently prevents the cua device from being re-opened.
.Sh SEE ALSO
.Xr ioctl 2 ,
.Xr sbus 4 ,
.Xr tty 4 ,
.Xr wskbd 4
.Sh HISTORY
The
.Nm
driver first appeared in
.Bx 4.4 .
Support for the TIOCM*
.Xr ioctl 2 Ns s
appeared in
.Ox 2.3 .