dmb(4)dmb(4)Namedmb - DMB32 communications multiplexor
Syntax
device dmb0 at vaxbi? node? flags 0x????
vector dmbsint dmbaint dmblint
Description
A DMB32 device provides eight asynchronous communication lines with
modem control. The device driver also supports a connection to a line
printer through the line printer port of the DMB32.
Each line attached to a DMB32 serial line port behaves as described in
Input and output for each line may independently be set to run at any
of 16 speeds. See for the encoding.
Bit i of flags can be specified for a to say that a line should be
treated as a hardwired connection, with carrier always present. If bit
i of flags is not set, the line operates under full modem control.
Modem lines will operate in accordance to the CD (carrier detect), DSR
(data set ready) and CTS (clear to send) leads. Thus, specifying
``flags 0x0004'' in the specification of would cause line 2 on the
DMB32 to be treated as hardwired, with carrier always present. In this
example, the remainder of the lines will be modem control lines.
Restrictions
The DMB32 provides a synchronous port, but this is not supported by the
driver.
Diagnostics
dmbinit: async lines unavailable
This message is produced at system boot time, if the DMB32 fails its
internal self test, indicating that the asynchronous lines have failed
to configure.
dmbinit: printer port unavailable
This message is produced at system boot time, if the DMB32 fails its
internal self test, indicating that the printer port failed to config‐
ure.
dmb%d: fifo overflow
The character input fifo overflowed before it could be serviced. This
can happen if the CPU is running with elevated priority for too long a
period of time. Overflow errors can indicate that configuration con‐
straints have been reached.
dmb%d: DMA Error. tbuf = 0x%x
A DMA output transfer failed. This can be caused by a memory error or
an invalid pte (page table entry). For a description of the error code
in the ``tbuf'' register, see the DMB32 documentation.
dmb%d: DMB Hardware Error. TX.DMA.START failed
The failed to clear the start bit. Normally, this is cleared to signal
that a DMA transfer has completed.
dmb%d: Modem Error. tbuf = 0x%x
Indicates a problem with a modem or its cable. For a description of
the error code in the ``tbuf'' register, see the DMB32 documentation.
dmb%d: Internal Error. tbuf = 0x%x
Indicates that the DMB32 detected an internal error. For a description
of the error code in the ``tbuf'' register, see the DMB32 documenta‐
tion.
hfBdmb%d: uio move error
An error occurred when copying a printer buffer from user space to sys‐
tem space.
dmbsint
The unsupported synchronous port of the DMB32 interrupted because of a
problem. Check your interrupt vectors for a conflict with another
device.
Files
(modem lines only)
See Alsotty(4), MAKEDEV(8), dmbsp(4)dmb(4)