136 lines
4.0 KiB
Groff
136 lines
4.0 KiB
Groff
.\" $NetBSD: dh.4,v 1.4 1997/10/19 12:59:04 mrg Exp $
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.\"
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.\" Copyright (c) 1980, 1991, 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by the University of
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.\" California, Berkeley and its contributors.
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.\" 4. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" from: @(#)dh.4 8.1 (Berkeley) 6/5/93
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.\"
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.Dd June 5, 1993
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.Dt DH 4 vax
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.Os BSD 4
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.Sh NAME
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.Nm dh
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.Nd
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.Tn DH-11 Ns / Tn DM-11
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multiplexer device interface
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.Sh SYNOPSIS
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.Cd "device dh0 at uba0 csr 0160020 vector dhrint dhxint" Op Ar flags
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.Cd "device dm0 at uba0 csr 0170500 vector dmintr" Op Ar flags
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.Sh DESCRIPTION
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A
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.Tn DH-11
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provides 16 serial communication lines;
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.Tn DM-11 Ns s
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may optionally be
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paired with
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.Tn DH-11 Ns s
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to provide modem control for the lines.
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.Pp
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An optional argument
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.Ar flags
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may be supplied with the device specification
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in the
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.Xr config 8
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file indicating
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that the line corresponding to
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bit number
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.Ar i
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is not properly
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connected, and should be treated as hard-wired with carrier
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always present. Thus specifying
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.Ql flags 0x0004
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for
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.Li dh0
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would cause line
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.Pa ttyh2
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to be treated in this way.
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.Pp
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Normal I/O
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control parameters for individual lines are managed by
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.Xr ioctl 2
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calls.
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Line speeds may be initiated via
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.Xr getty 8
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and
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.Xr stty 1
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or may be communicated by other programs which
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utilize
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.Xr ioctl
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such as
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.Xr ifcongif 8 ,
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see
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.Xr tty 4 .
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.Pp
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The
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.Nm dh
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driver monitors the rate of input on each board,
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and switches between the use of character-at-a-time interrupts
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and input silos.
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While the silo is enabled during periods of high-speed input,
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the driver polls for input 30 times per second.
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.Sh FILES
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.Bl -tag -width /dev/tty[h-o][0-9a-f]x -compact
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.It Pa /dev/tty[h-o][0-9a-f]
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.It Pa /dev/ttyd[0-9a-f]
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.El
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.Sh DIAGNOSTICS
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.Bl -diag
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.It dh%d: NXM.
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No response from
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.Tn UNIBUS
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on a dma transfer
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within a timeout period. This is often followed by a
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.Tn UNIBUS
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adapter
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error. This occurs most frequently when the
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.Tn UNIBUS
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is heavily loaded
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and when devices which hog the bus (such as
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.Tn RK07 Ns s) are present.
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It is not serious.
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.Pp
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.It dh%d: silo overflow.
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The character input silo overflowed
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before it could be serviced. This can happen if a hard error occurs
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when the
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.Tn CPU
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is running with elevated priority, as the system will
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then print a message on the console with interrupts disabled.
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It is not serious.
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.El
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.Sh SEE ALSO
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.Xr tty 4
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.Sh HISTORY
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A
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.Nm
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driver appeared in
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.At v6 .
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