NetBSD/share/man/man4/lpt.4

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.\" Copyright (c) 1993 Christopher G. Demetriou
.\" Copyright (c) 1994 Geoffrey M. Rehmet
.\" Copyright (c) 1999 Nicolas Souchu
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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Secondly, inb()/outb() calls have been replaced by ppbus
function calls.
lpt is now arch-independent thanks to the ppbus interface.
See
.Xr ppbus 4
for more information about the parallel port bus system.
.Pp
The parallel port bus is reserved by lpt 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.
.Pp
.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 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 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.
.Sh AUTHORS
This manual page was based on the FreeBSD
.Xr lpt 4
manual page. The information has been updated for NetBSD's 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 .
A 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.