1.\" $NetBSD: dh.4,v 1.3 1996/03/03 17:13:20 thorpej Exp $ 2.\" 3.\" Copyright (c) 1980, 1991 Regents of the University of California. 4.\" All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. All advertising materials mentioning features or use of this software 15.\" must display the following acknowledgement: 16.\" This product includes software developed by the University of 17.\" California, Berkeley and its contributors. 18.\" 4. Neither the name of the University nor the names of its contributors 19.\" may be used to endorse or promote products derived from this software 20.\" without specific prior written permission. 21.\" 22.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32.\" SUCH DAMAGE. 33.\" 34.\" from: @(#)dh.4 6.3 (Berkeley) 3/27/91 35.\" 36.Dd March 27, 1991 37.Dt DH 4 vax 38.Os BSD 4 39.Sh NAME 40.Nm dh 41.Nd 42.Tn DH-11 Ns / Tn DM-11 43multiplexer device interface 44.Sh SYNOPSIS 45.Cd "device dh0 at uba0 csr 0160020 vector dhrint dhxint" Op Ar flags 46.Cd "device dm0 at uba0 csr 0170500 vector dmintr" Op Ar flags 47.Sh DESCRIPTION 48A 49.Tn DH-11 50provides 16 serial communication lines; 51.Tn DM-11 Ns s 52may optionally be 53paired with 54.Tn DH-11 Ns s 55to provide modem control for the lines. 56.Pp 57An optional argument 58.Ar flags 59may be supplied with the device specification 60in the 61.Xr config 8 62file indicating 63that the line corresponding to 64bit number 65.Ar i 66is not properly 67connected, and should be treated as hard-wired with carrier 68always present. Thus specifying 69.Ql flags 0x0004 70for 71.Li dh0 72would cause line 73.Pa ttyh2 74to be treated in this way. 75.Pp 76Normal I/O 77control parameters for individual lines are managed by 78.Xr ioctl 2 79calls. 80Line speeds may be initiated via 81.Xr getty 8 82and 83.Xr stty 1 84or may be communicated by other programs which 85utilize 86.Xr ioctl 87such as 88.Xr ifcongif 8 , 89see 90.Xr tty 4 . 91.Pp 92The 93.Nm dh 94driver monitors the rate of input on each board, 95and switches between the use of character-at-a-time interrupts 96and input silos. 97While the silo is enabled during periods of high-speed input, 98the driver polls for input 30 times per second. 99.Sh FILES 100.Bl -tag -width /dev/tty[h-o][0-9a-f]x -compact 101.It Pa /dev/tty[h-o][0-9a-f] 102.It Pa /dev/ttyd[0-9a-f] 103.El 104.Sh DIAGNOSTICS 105.Bl -diag 106.It dh%d: NXM. 107No response from 108.Tn UNIBUS 109on a dma transfer 110within a timeout period. This is often followed by a 111.Tn UNIBUS 112adapter 113error. This occurs most frequently when the 114.Tn UNIBUS 115is heavily loaded 116and when devices which hog the bus (such as 117.Tn RK07 Ns s) are present. 118It is not serious. 119.Pp 120.It dh%d: silo overflow. 121The character input silo overflowed 122before it could be serviced. This can happen if a hard error occurs 123when the 124.Tn CPU 125is running with elevated priority, as the system will 126then print a message on the console with interrupts disabled. 127It is not serious. 128.El 129.Sh SEE ALSO 130.Xr tty 4 131.Sh HISTORY 132A 133.Nm 134driver appeared in 135.At v6 . 136