1*47674Scael.\" Copyright (c) 1980, 1991 Regents of the University of California. 2*47674Scael.\" All rights reserved. 320647Smckusick.\" 4*47674Scael.\" %sccs.include.redist.man% 520647Smckusick.\" 6*47674Scael.\" @(#)dh.4 6.3 (Berkeley) 03/27/91 7*47674Scael.\" 8*47674Scael.Dd 9*47674Scael.Dt DH 4 vax 10*47674Scael.Os BSD 4 11*47674Scael.Sh NAME 12*47674Scael.Nm dh 13*47674Scael.Nd 14*47674Scael.Tn DH-11 Ns / Tn DM-11 15*47674Scaelmultiplexer device interface 16*47674Scael.Sh SYNOPSIS 17*47674Scael.Cd "device dh0 at uba0 csr 0160020 vector dhrint dhxint" Op Ar flags 18*47674Scael.Cd "device dm0 at uba0 csr 0170500 vector dmintr" Op Ar flags 19*47674Scael.Sh DESCRIPTION 20*47674ScaelA 21*47674Scael.Tn DH-11 22*47674Scaelprovides 16 serial communication lines; 23*47674Scael.Tn DM-11 Ns s 24*47674Scaelmay optionally be 25*47674Scaelpaired with 26*47674Scael.Tn DH-11 Ns s 27*47674Scaelto provide modem control for the lines. 28*47674Scael.Pp 29*47674ScaelAn optional argument 30*47674Scael.Ar flags 31*47674Scaelmay be supplied with the device specification 32*47674Scaelin the 33*47674Scael.Xr config 8 34*47674Scaelfile indicating 35*47674Scaelthat the line corresponding to 36*47674Scaelbit number 37*47674Scael.Ar i 38*47674Scaelis not properly 39*47674Scaelconnected, and should be treated as hard-wired with carrier 40*47674Scaelalways present. Thus specifying 41*47674Scael.Ql flags 0x0004 42*47674Scaelfor 43*47674Scael.Li dh0 44*47674Scaelwould cause line 45*47674Scael.Pa ttyh2 46*47674Scaelto be treated in this way. 47*47674Scael.Pp 48*47674ScaelNormal I/O 49*47674Scaelcontrol parameters for individual lines are managed by 50*47674Scael.Xr ioctl 2 51*47674Scaelcalls. 52*47674ScaelLine speeds may be initiated via 53*47674Scael.Xr getty 8 54*47674Scaeland 55*47674Scael.Xr stty 1 56*47674Scaelor may be communicated by other programs which 57*47674Scaelutilize 58*47674Scael.Xr ioctl 59*47674Scaelsuch as 60*47674Scael.Xr ifcongif 8 , 6120647Smckusicksee 62*47674Scael.Xr tty 4 . 63*47674Scael.Pp 6428259SkarelsThe 65*47674Scael.Nm dh 6628259Skarelsdriver monitors the rate of input on each board, 6728259Skarelsand switches between the use of character-at-a-time interrupts 6828259Skarelsand input silos. 6928259SkarelsWhile the silo is enabled during periods of high-speed input, 7028259Skarelsthe driver polls for input 30 times per second. 71*47674Scael.Sh FILES 72*47674Scael.Bl -tag -width /dev/tty[h-o][0-9a-f]x -compact 73*47674Scael.It Pa /dev/tty[h-o][0-9a-f] 74*47674Scael.It Pa /dev/ttyd[0-9a-f] 75*47674Scael.El 76*47674Scael.Sh DIAGNOSTICS 77*47674Scael.Bl -diag 78*47674Scael.It dh%d: NXM. 79*47674ScaelNo response from 80*47674Scael.Tn UNIBUS 81*47674Scaelon a dma transfer 82*47674Scaelwithin a timeout period. This is often followed by a 83*47674Scael.Tn UNIBUS 84*47674Scaeladapter 85*47674Scaelerror. This occurs most frequently when the 86*47674Scael.Tn UNIBUS 87*47674Scaelis heavily loaded 88*47674Scaeland when devices which hog the bus (such as 89*47674Scael.Tn RK07 Ns s) are present. 9020647SmckusickIt is not serious. 91*47674Scael.Pp 92*47674Scael.It dh%d: silo overflow. 93*47674ScaelThe character input silo overflowed 9420647Smckusickbefore it could be serviced. This can happen if a hard error occurs 95*47674Scaelwhen the 96*47674Scael.Tn CPU 97*47674Scaelis running with elevated priority, as the system will 9828259Skarelsthen print a message on the console with interrupts disabled. 9920647SmckusickIt is not serious. 100*47674Scael.El 101*47674Scael.Sh SEE ALSO 102*47674Scael.Xr tty 4 103*47674Scael.Sh HISTORY 104*47674ScaelA 105*47674Scael.Nm 106*47674Scaeldriver appeared in 107*47674Scael.At v6 . 108