PPI(9)

PPI(9) | Kernel Developer's Manual | PPI(9)

# 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.

December 29, 2003 | NetBSD 8.3