xref: /original-bsd/share/man/man4/man4.vax/dmf.4 (revision 38ca7aa6)
1.\" Copyright (c) 1983, 1991, 1993
2.\"	The Regents of the University of California.  All rights reserved.
3.\"
4.\" %sccs.include.redist.man%
5.\"
6.\"     @(#)dmf.4	8.1 (Berkeley) 06/05/93
7.\"
8.Dd
9.Dt DMF 4 vax
10.Os BSD 4.2
11.Sh NAME
12.Nm dmf
13.Nd
14.Tn DMF-32
15terminal multiplexor
16.Sh SYNOPSIS
17.Cd "device dmf0 at uba? csr 0160340 vector dmfsrint dmfsxint dmfdaint dmfdbint dmfrint dmfxint dmflint"
18.Sh DESCRIPTION
19The
20.Nm dmf
21device provides 8 lines of asynchronous serial line support.
22The first two of these have full modem control.
23The device also provides a line printer port
24similar to the
25.Tn LP-11 .
26Other features of the
27.Tn DMF-32
28are not supported.
29During autoconfiguration, the driver examines the configuration of each
30.Tn DMF-32
31and adjusts the interrupt vectors so that fewer vector locations are used
32if possible.
33.Pp
34An optional argument
35.Ar flags
36may be supplied with the device specification
37in the config file indicating
38that the line corresponding to
39bit number
40.Ar i
41is not properly
42connected, and should be treated as hard-wired with carrier
43always present.  Thus specifying
44.Ql flags 0x04
45for
46.Li dmf0
47would cause line
48.Pa ttyA2
49to be treated in this way.
50Flags should be set for all lines without hardware support for modem control.
51.Pp
52Normal
53.Tn I/O
54control parameters for individual lines are managed by
55.Xr ioctl 2
56calls.
57Line speeds may be initiated via
58.Xr getty 8
59and
60.Xr stty 1
61or may be communicated by other programs which
62utilize
63.Xr ioctl
64such as
65.Xr ifcongif 8 ,
66see
67.Xr tty 4  .
68.Pp
69The serial line part of the
70.Nm dmf
71driver normally enables the input silos with a short timeout
72(30 milliseconds); this allows multiple characters to be received
73per interrupt during periods of high-speed input.
74.Pp
75A line printer port on a
76.Nm dmf
77is designated by
78a minor device number of the form
79.Pf 128+ Ns Ar n .
80See
81.Xr MAKEDEV 8 .
82Column and lines per page may be changed from the default
83132 columns and 66 lines by encoding the number of columns
84in bits 8-15 of flags and the number of lines in bits 16-23.
85This device does not provide the fancy output canonicalization
86features of the
87.Xr lp 4
88driver.
89.Sh FILES
90.Bl -tag -width "/dev/tty[A-CE-I][0-7]" -compact
91.It Pa /dev/tty[A-CE-I][0-7]
92.It Pa /dev/ttyd[0-7]
93.It Pa /dev/lp
94.El
95.Sh DIAGNOSTICS
96.Bl -diag
97.It dmf%d: NXM line %d.
98No response from
99.Tn UNIBUS
100on a DMA transfer
101within a timeout period.  This is often followed by a
102.Tn UNIBUS
103adapter
104error.  This occurs most frequently when the
105.Tn UNIBUS
106is heavily loaded
107and when devices which hog the bus (such as
108.Tn RK07 Ns s )
109are present.
110It is not serious.
111.Pp
112.It dmf%d: silo overflow.
113The character input silo overflowed
114before it could be serviced.  This can happen if a hard error occurs
115when the
116.Tn CPU
117is running with elevated priority, as the system will
118then print a message on the console with interrupts disabled.
119It is not serious.
120.Pp
121.It dmfsrint, dmfsxint, dmfdaint, dmfdbint.
122One of the unsupported parts of the dmf interrupted; something
123is amiss, check your interrupt vectors for a conflict with another
124device.
125.El
126.Sh SEE ALSO
127.Xr tty 4
128.Sh HISTORY
129The
130.Nm
131driver appeared in
132.Bx 4.2 .
133.Sh BUGS
134It should be possible to set the silo timeout with a configuration file option,
135as the value is a trade-off between efficiency and response time for flow
136control and character echo.
137