LPT (4) NetBSD Programmer's Manual LPT (4)

NAME

lpt: generic printer device driver

SYNOPSIS

lpt* at ppbus?
options LPT_DEBUG
options LPT_VERBOSE

DESCRIPTION

The lpt driver is the port of the lpt driver to the ppbus(4) system.

One purpose of this port was to allow parallel port sharing with other parallel devices. Secondly, inb()/outb() calls have been replaced by ppbus function calls. lpt is now arch-independent thanks to the ppbus interface. See ppbus(4) for more information about the parallel port bus system.

The parallel port bus is reserved by lpt when the printer device is opened and released when the device is closed.

Ports can be configured to use DMA, IEEE negotiations, and IEEE compliant transfer modes by using the lptctl(8) command, with modes depending on the hardware available.

Minor bit

The minor bit selects some device features:

Minor Bit	Function
128	Do no use interrupts (polled accesses)
64	Do not initialize printer when opened
32	Automatic LF on CR

mknod(8) can be used to create such devices if necessary (see BUGS).

FILES

/dev/lpt?: interrupt-driven ports (minor number 0)
/dev/lpa?: polled ports (minor number 128)

HISTORY

This driver is derived from drivers which appear in FreeBSD and NetBSD. The FreeBSD driver is used for ppbus usage while the NetBSD driver's behavior is emulated as much as possible for compatibility.

AUTHORS

This manual page was based on the FreeBSD lpt(4) manual page. The information has been updated for NetBSD's port by Gary Thorpe.

BUGS

If a printer is not connected and on-line, /dev/lpt? and /dev/lpa? cannot be used with lptctl(8). A lpt device with minor number 64 must be used in this case because it skips the initialization sequence.
Testing has been limited by hardware availability.

December 24, 2003