117 lines
4.0 KiB
Groff
117 lines
4.0 KiB
Groff
.\"
|
|
.\" Copyright (c) 1996 Jonathan Stone.
|
|
.\" All rights reserved.
|
|
.\"
|
|
.\" 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 Jonathan Stone.
|
|
.\" 3. The name of the author may not be used to endorse or promote products
|
|
.\" derived from this software without specific prior written permission
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
|
|
.\"
|
|
.\" $NetBSD: dc.4,v 1.3 1998/02/23 19:46:24 jonathan Exp $
|
|
.\"
|
|
.Dd February 20, 1998
|
|
.Dt DC 4 pmax
|
|
.Os NetBSD
|
|
.Sh NAME
|
|
.Nm dc
|
|
.Nd
|
|
dc659, dc7085 DZ11-on-a-chip serial communications interface
|
|
.Sh SYNOPSIS
|
|
.Cd "dc0 at ioasic?"
|
|
.Cd "dc0 at mainbus"
|
|
.Cd "dc1 at mainbus"
|
|
.Cd "dc2 at mainbus"
|
|
.Sh DESCRIPTION
|
|
THe
|
|
.Nm
|
|
driver provides support for Digital's dc7085 four-port serial
|
|
communcations chip.
|
|
The
|
|
.Nm dc
|
|
driver supports dc7085 hardware on attached to the following
|
|
parent devices:
|
|
.Pp
|
|
.Bl -tag -width speaker -offset indent -compact
|
|
.It mainbus
|
|
baseboard device on Decstation 2100, 3100, and 5100,
|
|
and optional expansion devices on the 5100.
|
|
.It ioasic
|
|
baseboard device on Decstation 5000/200.
|
|
.It vsbus
|
|
baseboard devices on the Vaxstation 2000 and 3100.
|
|
.El
|
|
.Pp
|
|
The
|
|
.Nm
|
|
device is in essence a single-chip clone of the DZ-11.
|
|
The DZ-11 hardware design severely constrains performance.
|
|
One small input silo is shared across all input ports.
|
|
The
|
|
.Nm dc
|
|
hardware does not interrupt on modem transitions; instead,
|
|
they are detected via polling.
|
|
Only two lines on a baseboard
|
|
.Nm dc
|
|
device have any modem control signals;
|
|
the other two lines are wired for a keyboard and mouse.
|
|
|
|
On some implementations (e.g., Decstation 3100), the hardware does not
|
|
bring out modem flow-control signals to the bulkhead. Only modem
|
|
carrier transition are provided. This is adequate for Unix dialin
|
|
and dialout detection, but without hardware flow control, the
|
|
.Nm
|
|
device is prone to overruns when used for serial-line protocols.
|
|
|
|
The Decstation 5000/200
|
|
.Nm
|
|
hardware provides full modem control on
|
|
both bulkhead RS-232 ports and is less prone to overrun.
|
|
.Sh BUGS
|
|
.Pp
|
|
The 19200 speed on all
|
|
.Nm
|
|
devices is actually implemented as 19800,
|
|
presumably for bug-compatibility with the original DZ-11.
|
|
This is a hardware feature and cannot be corrected in software.
|
|
Many serial devices at 19200 fail to interoperate with the
|
|
.Nm
|
|
at its 19800 speed setting.
|
|
.Pp
|
|
The Decstation 5000/200 can set a bit in the system register
|
|
to allow the
|
|
.Nm
|
|
to run at 38400, but this applies to all four lines and disables
|
|
the 19200 speed on all four lines. This feature is not currently supported.
|
|
.Pp
|
|
The
|
|
.Nm
|
|
driver should be merged into a single driver supporting the original
|
|
DZ-11, DZ-32, and Qbus DZV-11 and DZQ-11 clones.
|
|
.Sh HISTORY
|
|
The
|
|
.Nm
|
|
driver
|
|
first appeared in
|
|
.Bx 4.4 /pmax. This manual page first appeared in
|
|
.Nx 1.2 .
|