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Annotation of 43BSDTahoe/man/man4/vax/dhu.4, revision 1.1

1.1     ! root        1: .\" Copyright (c) 1985 Regents of the University of California.
        !             2: .\" All rights reserved.  The Berkeley software License Agreement
        !             3: .\" specifies the terms and conditions for redistribution.
        !             4: .\"
        !             5: .\"    @(#)dhu.4       6.2 (Berkeley) 4/27/86
        !             6: .\"
        !             7: .TH DHU 4 "April 27, 1986"
        !             8: .UC 6
        !             9: .SH NAME
        !            10: dhu \- DHU-11 communications multiplexer
        !            11: .SH SYNOPSIS
        !            12: .B "device dhu0 at uba0 csr 0160440 vector dhurint dhuxint"
        !            13: .SH DESCRIPTION
        !            14: A DHU-11 provides 16 communication lines.
        !            15: .PP
        !            16: Each line attached to the DHU-11 communications multiplexer
        !            17: behaves as described in
        !            18: .IR tty (4).
        !            19: Input and output for each line may independently
        !            20: be set to run at any of 13 speeds (50, 200 and 38400 baud are not available);
        !            21: see
        !            22: .IR tty (4)
        !            23: for the encoding.
        !            24: .PP
        !            25: Bit
        !            26: .I i
        !            27: of flags may be specified for a DHU-11 to say that a line is not properly
        !            28: connected, and that the line should be treated as hard-wired with carrier
        !            29: always present.  Thus specifying ``flags 0x0004'' in the specification of dhu0
        !            30: would cause line ttyS2 to be treated in this way.
        !            31: .PP
        !            32: The DHU-11 driver normally uses input silos
        !            33: and delays receiver interrupts by 20 milliseconds
        !            34: rather than taking an interrupt on each input character.
        !            35: .SH FILES
        !            36: /dev/tty[S-Z][0-9a-f]
        !            37: .SH "SEE ALSO"
        !            38: tty(4)
        !            39: .SH DIAGNOSTICS
        !            40: \fBdhu(%d,%d): NXM fault\fR.  No response from UNIBUS on a DMA transfer
        !            41: within a timeout period.  This is often followed by a UNIBUS adapter
        !            42: error.  This occurs most frequently when the UNIBUS is heavily loaded
        !            43: and when devices which hog the bus (such as RK07s) are present.
        !            44: It is not serious.
        !            45: .PP
        !            46: \fBdhu%d: silo overflow\fR.  The character input silo overflowed
        !            47: before it could be serviced.  This can happen if a hard error occurs
        !            48: when the CPU is running with elevated priority, as the system may
        !            49: then print a message on the console with interrupts disabled.
        !            50: .SH NOTES
        !            51: The driver currently does not make full use of the hardware
        !            52: capabilities of the DHU-11, for dealing with XON/XOFF flow-control or hard-wired
        !            53: lines for example.
        !            54: .PP
        !            55: Although the devices are not the same, a DHU-11 can convince the
        !            56: DH-11 autoconfiguration code that it is a DH-11.
        !            57: .PP
        !            58: The 4 40-way cables are a pain.

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