.\" $NetBSD: ppi.9,v 1.3 2004/01/23 19:50:43 wiz Exp $
.\"
.\" Copyright (c) 1997
.\"      Michael Smith
.\"
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.\" $FreeBSD: src/share/man/man4/ppi.4,v 1.4.2.7 2001/12/17 11:30:12 ru Exp $
.\"
.Dd December 29, 2003
.Dt PPI 9
.Os
.Sh NAME
.Nm ppi
.Nd "user-space interface to ppbus parallel port"
.Sh SYNOPSIS
.In sys/ioctl.h
.In dev/ppbus/ppi.h
.In dev/ppbus/ppbus_conf.h
.Sh DESCRIPTION
All I/O on the
.Nm
interface is performed using
.Fn ioctl
calls.
Each command takes a single
.Ft u_int8_t
argument, transferring one byte of data.
The following commands are available:
.Bl -tag -width indent
.It Dv PPIGDATA , PPISDATA
Get and set the contents of the data register.
.It Dv PPIGSTATUS , PPISSTATUS
Get and set the contents of the status register.
.It Dv PPIGCTRL , PPISCTRL
Get and set the contents of the control register.
The following defines correspond to bits in this register.
Setting a bit in the control register drives the corresponding
output low.
.Bl -tag -width indent -compact
.It Dv STROBE
.It Dv AUTOFEED
.It Dv nINIT
.It Dv SELECTIN
.It Dv PCD
.El
.It Dv PPIGEPP , PPISEPP
Get and set the contents of the EPP control register.
.It Dv PPIGECR , PPISECR
Get and set the contents of the ECP control register.
.It Dv PPIGFIFO , PPISFIFO
Read and write the ECP FIFO (8-bit operations only).
.El
.Sh EXAMPLES
To present the value 0x5a to the data port, drive STROBE low and
then high again, the following code fragment can be used:
.Bd -literal -compact
	int		fd;
	u_int8_t	val;

	val = 0x5a;
	ioctl(fd, PPISDATA, \*[Am]val);
	ioctl(fd, PPIGCTRL, \*[Am]val);
	val |= STROBE;
	ioctl(fd, PPISCTRL, \*[Am]val);
	val \*[Am]= ~STROBE;
	ioctl(fd, PPISCTRL, \*[Am]val);

.Ed
.Sh SEE ALSO
.Xr ioctl 2 ,
.Xr atppc 4 ,
.Xr io 4 ,
.Xr ppbus 4 ,
.Xr ppi 4
.Sh HISTORY
.Nm
originally appeared in
.Fx .
.Sh AUTHORS
This manual page is based on the
.Fx
.Nm ppi
manual page and was updated for the
.Nx
port by
.An Gary Thorpe .
.Sh BUGS
The inverse sense of signals is confusing.
.Pp
The
.Fn ioctl
interface is slow, and there is no way (yet) to chain multiple operations together.
.Pp
The headers required for user applications are not installed as part of the
standard system.