for the tty part of the z8530 driver

share/man/man4/zstty.4

@@ -0,0 +1,91 @@
+.\"	$NetBSD: zstty.4,v 1.1 1997/10/28 17:14:53 gwr Exp $
+.\"
+.\" Copyright (c) 1997 The NetBSD Foundation, Inc.
+.\" All rights reserved.
+.\"
+.\" This code is derived from software contributed to The NetBSD Foundation
+.\" by Gordon W. Ross.
+.\"
+.\" 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
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 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 NetBSD
+.\"        Foundation, Inc. and its contributors.
+.\" 4. Neither the name of The NetBSD Foundation nor the names of its
+.\"    contributors may be used to endorse or promote products derived
+.\"    from this software without specific prior written permission.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+.\" PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
+.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+.\" POSSIBILITY OF SUCH DAMAGE.
+.\"
+.Dd October 23, 1997
+.Dt ZSTTY 4
+.Os NetBSD 1.3
+.Sh NAME
+.Nm zstty
+.Nd
+serial communications interface
+.Sh SYNOPSIS
+.Cd "zstty* at zs0"  Pq sparc
+.Cd "zstty* at zsc1" Pq others
+.Sh DESCRIPTION
+The
+.Nm
+driver provides TTY support for Zilog 8530 Dual UARTS.
+.Pp
+Input and output for each line may set to any baud rate in the
+range 50 to 38400 (and higher on some machines).
+.Sh FILES
+.Bl -tag -width Pa
+.It Pa /dev/ttya
+.It Pa /dev/ttyb
+.El
+.Sh DIAGNOSTICS
+.Bl -tag -width indent -compact
+.It zs0*: fifo overflow
+.br
+The on-chip
+.Dq fifo
+has overflowed and incoming data has been lost.
+This generally means the machine is not responding to
+interrupts from the ZS chip fast enough, which can be
+remedied only by using a lower baud rate.
+.It zs0*: ring overflow
+.br
+The software input
+.Dq ring
+has overflowed.  This usually means input flow-control
+is not configured correctly (i.e. incorrect cable wiring).
+.El
+.Sh SEE ALSO
+.Xr scc 4
+.Xr tty 4
+.Sh HISTORY
+The
+.Nm
+driver was derived from the
+.Nm sparc
+.Nm zs
+driver supplied with 4.4 BSD.
+.Ud
+.Sh BUGS
+The old Zilog 8530 chip has a very small fifo (3 bytes?) and
+therefore has very strict latency requirements for the
+interrupt service routine.  This limits the usable baud rates
+on many machines.