DL(4)

NAME
dl - DL-11/DLV-11 serial device driver

SYNOPSIS
dl0 at uba? csr 0176500
dl1 at uba? csr 0176510
dl2 at uba? csr 0176520
dl3 at uba? csr 0176530

DESCRIPTION
The dl driver controls a DL-11-compatible asynchronous serial card, and probably things compatible with it. A four-port DLV-11J will appear four times in the device list, as the ports look like separate cards to the driver.

The dl driver provides the normal interface described in tty(4), but many of the configuration calls are unsupported, since their functions are handled by jumpers or switches on the serial card itself. Calls related to modem-control lines are also ignored, since these cards lack them.

There's a chance this driver might also work with an LP11, an LPV11 or even a PC11, but it hasn't been tested.

FILES
/dev/ttyJ?
    Special files for communicating with dl devices.

DIAGNOSTICS

dl%d: rx overrun. The character in the receive buffer wasn't read before the next character arrived, and has been lost.

dl%d: stray rx interrupt. The driver was called to service a receive interrupt, but there was nothing for it to read.

SEE ALSO
tty(4)

HISTORY
The dl driver was written for NetBSD 1.3.

AUTHORS
Ben Harris <bjh21@NetBSD.org>

BUGS
The DL-11 and friends only have single-character receive and transmit buffers, so an interrupt is generated for every character received or transmitted. Attempting to receive data at even moderately high rates will cause rx overruns. Fast transmission seems to be fine though.

There is no support in the driver for the paper-tape reader on an LT33 attached via a DLV-11KA or similar.

The overrun message is logged in the interrupt routine itself, which will probably just make the problem worse.

The CSR printed on startup is that of the receiver, while the interrupt vector is that of the transmitter.

In order to determine the card's interrupt vector, the driver sends a NUL to each port. This may confuse things attached to them.

The driver has so far only been tested on a DLV-11J. It may or may not work on the other cards it claims to support.