1.\" $NetBSD: zstty.4,v 1.4 2001/09/11 23:18:56 wiz Exp $ 2.\" 3.\" Copyright (c) 1997 The NetBSD Foundation, Inc. 4.\" All rights reserved. 5.\" 6.\" This code is derived from software contributed to The NetBSD Foundation 7.\" by Gordon W. Ross. 8.\" 9.\" Redistribution and use in source and binary forms, with or without 10.\" modification, are permitted provided that the following conditions 11.\" are met: 12.\" 1. Redistributions of source code must retain the above copyright 13.\" notice, this list of conditions and the following disclaimer. 14.\" 2. Redistributions in binary form must reproduce the above copyright 15.\" notice, this list of conditions and the following disclaimer in the 16.\" documentation and/or other materials provided with the distribution. 17.\" 3. All advertising materials mentioning features or use of this software 18.\" must display the following acknowledgement: 19.\" This product includes software developed by the NetBSD 20.\" Foundation, Inc. and its contributors. 21.\" 4. Neither the name of The NetBSD Foundation nor the names of its 22.\" contributors may be used to endorse or promote products derived 23.\" from this software without specific prior written permission. 24.\" 25.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 26.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 27.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 28.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 29.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 30.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 31.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 32.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 33.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 34.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 35.\" POSSIBILITY OF SUCH DAMAGE. 36.\" 37.Dd October 23, 1997 38.Dt ZSTTY 4 39.Os 40.Sh NAME 41.Nm zstty 42.Nd 43serial communications interface 44.Sh SYNOPSIS 45.Cd "zstty* at zs0" Pq sparc 46.Cd "zstty* at zsc1" Pq others 47.Sh DESCRIPTION 48The 49.Nm 50driver provides TTY support for Zilog 8530 Dual UARTS. 51.Pp 52Input and output for each line may set to any baud rate in the 53range 50 to 38400 (and higher on some machines). 54.Sh FILES 55.Bl -tag -width Pa 56.It Pa /dev/ttya 57.It Pa /dev/ttyb 58.El 59.Sh DIAGNOSTICS 60.Bl -tag -width indent -compact 61.It zs0*: fifo overflow 62.br 63The on-chip 64.Dq fifo 65has overflowed and incoming data has been lost. 66This generally means the machine is not responding to 67interrupts from the ZS chip fast enough, which can be 68remedied only by using a lower baud rate. 69.It zs0*: ring overflow 70.br 71The software input 72.Dq ring 73has overflowed. This usually means input flow-control 74is not configured correctly (i.e. incorrect cable wiring). 75.El 76.Sh SEE ALSO 77.Xr scc 4 , 78.Xr tty 4 79.Sh HISTORY 80The 81.Nm 82driver was derived from the 83.Nm sparc 84.Nm zs 85driver supplied with 86.Bx 4.4 . 87.Ud 88.Sh BUGS 89The old Zilog 8530 chip has a very small fifo (3 bytes?) and 90therefore has very strict latency requirements for the 91interrupt service routine. This limits the usable baud rates 92on many machines. 93