dmb(4)
NAME
dmb − DMB32 communications multiplexor
SYNTAX
device dmb0 at vaxbi? node? flags 0x????
vector dmbsint dmbaint dmblint
DESCRIPTION
A DMB32 device provides eight 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 tty(.). Input and output for each line may independently be set to run at any of 16 speeds. See tty() for the encoding.
Bit i of flags may be specified for a dmb to say that a line is not properly connected, and that the line should be treated as hardwired with carrier always present. Thus, specifying “flags 0x0004” in the specification of dmb0 would cause line 2 on the DMB32 to be treated as hardwired with carrier always present.
RESTRICTIONS
The DMB32 provides a synchronous port, but this is not supported by the driver.
DIAGNOSTICS
dmbinit: device broken
This message is produced at system boot time if the DMB32 fails its internal self test.
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. No user interaction is required.
dmb%d: DMA Error. tbuf = 0x%x
A DMA output transfer failed. This could be caused by a memory error or an invalid pte. For a description of the error code in the "tbuf" register, see the DMB32 User Guide. The dmb 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 User Guide.
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 User Guide.
dmb%d: uio move error
An error occurred when copying a printer buffer from user space to system 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
/dev/tty??
/dev/ttyd?(modem lines only)