ppi.4

早期freebsd实现

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.\"     @(#)ppi.4	8.1 (Berkeley) 6/9/93
.\"
.Dd June 9, 1993
.Dt PPI 4 hp300
.Os
.Sh NAME
.Nm ppi
.Nd
.Tn HP-IB
printer/plotter interface
.Sh SYNOPSIS
.Cd "device ppi0 at hpib0 slave 5"
.Sh DESCRIPTION
The
.Nm ppi
interface provides a means of communication with
.Tn HP-IB
printers and plotters.
.Pp
Special files
.Pa ppi0
through
.Pa ppi7
are used to access the devices, with the digit at the end
of the filename referring to the bus address of the device.
Current versions of the autoconf code can not probe for these
devices, so the device entry in the configuration file must be
fully qualified.
.Pp
The device files appear as follows:
.Bd -literal -offset indent
"crw-rw-rw-  1 root      11,   0 Dec 21 11:22 /dev/ppi"
.Ed
.Sh DIAGNOSTICS
None.
.Sh SEE ALSO
.Xr hpib 4 .
.Sh BUGS
This driver is very primitive, it handshakes data out byte by byte.
It should use
.Tn DMA
if possible.