.\" Copyright (c) 1983 Regents of the University of California.
.\" All rights reserved. The Berkeley software License Agreement
.\" specifies the terms and conditions for redistribution.
.\" @(#)dmf.4 6.2 (Berkeley) %G%
dmf \- DMF-32, terminal multiplexor
.B "device dmf0 at uba? csr 0160340"
.B "vector dmfsrint dmfsxint dmfdaint dmfdbint dmfrint dmfxint dmflint"
device provides 8 lines of asynchronous serial line support. The first two
of these have full modem control
(the DMF-32 provides other services, but these are not supported by the driver).
Each line attached to a DMF-32 serial line port behaves as described
Input and output for each line may independently be set to run at any
of flags may be specified for a
to to say that a line is not properly connected, and that the
line should be treated as hard-wired with carrier always present.
Thus specifying ``flags 0x0004'' in the specification of
would cause line ttyh2 to be treated in this way.
driver normally uses input silos and polls for input at each clock
.BR "dmf%d: NXM line %d" .
No response from UNIBUS on a dma transfer
within a timeout period. This is often followed by a UNIBUS adapter
error. This occurs most frequently when the UNIBUS is heavily loaded
and when devices which hog the bus (such as rk07's) are present.
.BR "dmf%d: silo overflow" .
The character input silo overflowed
before it could be serviced. This can happen if a hard error occurs
when the CPU is running with elevated priority, as the system will
then print a message on the console with interrupts disabled. If the
line at high speed (e.g. 9600 baud), there is only 1/15th of a second of
buffering capacity in the silo, and overrun is possible. This may
cause a few input characters to be lost to users and a network
packet is likely to be corrupted, but the network will recover.
One of the unsupported parts of the dmf interrupted; something
is amiss, check your interrupt vectors for a conflict with another