NetBSD/share/man/man4/lpt.4

.\" $NetBSD: lpt.4,v 1.4 2004/01/23 15:59:18 wiz Exp $
.\"
.\"
.\" Copyright (c) 1993 Christopher G. Demetriou
.\" Copyright (c) 1994 Geoffrey M. Rehmet
.\" Copyright (c) 1999 Nicolas Souchu
.\" All rights reserved.
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.\" $FreeBSD: src/share/man/man4/lpt.4,v 1.9.2.2 2001/08/17 13:08:38 ru Exp $
.\"
.Dd December 24, 2003
.Dt LPT 4
.Os
.Sh NAME
.Nm lpt
.Nd generic printer device driver
.Sh SYNOPSIS
.Cd "lpt* at ppbus?"
.Cd options LPT_DEBUG
.Cd options LPT_VERBOSE
.Sh DESCRIPTION
The
.Nm
driver is the port of the lpt driver to the
.Xr ppbus 4
system.
.Pp
One purpose of this port was to allow parallel port sharing with
other parallel devices.
Secondly,
.Fn inb
and
.Fn outb
calls have been replaced by
.Xr ppbus 4
function calls.
.Nm
is now arch-independent thanks to the
.Xr ppbus 4
interface.
See
.Xr ppbus 4
for more information about the parallel port bus system.
.Pp
The parallel port bus is reserved by
.Nm
when the printer device is opened and released when the device is
closed.
.Pp
Ports can be configured to use DMA, IEEE negotiations, and IEEE
compliant transfer modes by using the
.Xr lptctl 8
command, with modes depending on the hardware available.
.Ss Minor bit
The minor bit selects some device features:
.Bl -column "Minor Bit" "Function" -offset indent
.It Em "Minor Bit"	Function
.It 128	Do no use interrupts (polled accesses).
.It 64	Do not initialize printer when opened.
.It 32	Automatic LF on CR.
.El
.Pp
.Xr mknod 8
can be used to create such devices if necessary (see
.Sx BUGS ) .
.Sh FILES
.Bl -tag -width "/dev/lpt0xx" -compact
.It Pa /dev/lpt?
interrupt-driven ports (minor number 0)
.It Pa /dev/lpa?
polled ports (minor number 128)
.El
.Sh SEE ALSO
.Xr atppc 4 ,
.Xr ppbus 4 ,
.Xr lptctl 8 ,
.Xr mknod 8
.Sh HISTORY
This driver is derived from drivers which appear in
.Fx
and
.Nx .
The
.Fx
driver is used for
.Xr ppbus 4
usage while the
.Nx
driver's behavior is emulated as much as possible for compatibility.
.Sh AUTHORS
This manual page was based on the
.Fx
.Nm lpt
manual page.
The information has been updated for the
.Nx
port by Gary Thorpe.
.Sh BUGS
If a printer is not connected and on-line,
.Pa /dev/lpt?
and
.Pa /dev/lpa?
cannot be used with
.Xr lptctl 8 .
An lpt device with minor number
.Em 64
must be used in this case because it skips the initialization
sequence.
.Pp
Testing has been limited by hardware availability.