NAME
ppi —
user-space interface to ppbus
parallel port
SYNOPSIS
#include <sys/ioctl.h>
#include <dev/ppbus/ppi.h>
#include <dev/ppbus/ppbus_conf.h>
DESCRIPTION
All I/O on the
ppi interface is performed using
ioctl() calls. Each command takes a single
uint8_t argument, transferring one byte of data. The
following commands are available:
-
-
PPIGDATA
,
PPISDATA
- Get and set the contents of the data register.
-
-
PPIGSTATUS
,
PPISSTATUS
- Get and set the contents of the status register.
-
-
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.
STROBE
-
AUTOFEED
-
nINIT
-
SELECTIN
-
PCD
-
-
-
PPIGEPP
,
PPISEPP
- Get and set the contents of the EPP control register.
-
-
PPIGECR
,
PPISECR
- Get and set the contents of the ECP control register.
-
-
PPIGFIFO
,
PPISFIFO
- Read and write the ECP FIFO (8-bit operations only).
EXAMPLES
To present the value 0x5a to the data port, drive STROBE low and then high
again, the following code fragment can be used:
int fd;
uint8_t val;
val = 0x5a;
ioctl(fd, PPISDATA, &val);
ioctl(fd, PPIGCTRL, &val);
val |= STROBE;
ioctl(fd, PPISCTRL, &val);
val &= ~STROBE;
ioctl(fd, PPISCTRL, &val);
SEE ALSO
ioctl(2),
atppc(4),
io(4),
ppbus(4),
ppi(4)
HISTORY
ppi originally appeared in
FreeBSD.
AUTHORS
This manual page is based on the
FreeBSD
ppi manual page and was updated for the
NetBSD port by
Gary Thorpe.
BUGS
The inverse sense of signals is confusing.
The
ioctl() interface is slow, and there is no way (yet) to
chain multiple operations together.
The headers required for user applications are not installed as part of the
standard system.