---
name: "ppi"
section: "4"
platform: "linux"
package: "freebsd-manpages"
version: "6.0-5"
release: "Debian 4.0 (Etch)"
platforms: ["linux", "freebsd"]
url: "https://new.carta.tech/ppi"
---

# ppi(4)

user-space interface to ppbus parallel 'geek' port

## NAME

**ppi** – user-space interface to ppbus parallel 'geek' port

## SYNOPSIS

**device ppi**

Minor numbering: unit numbers correspond directly to ppbus numbers.

**#include \<dev/ppbus/ppi.h\>**

**#include \<dev/ppbus/ppbconf.h\>**

## DESCRIPTION

The **ppi** driver provides a convenient means for user applications to manipulate the state of the parallel port, enabling easy low-speed I/O operations without the security problems inherent with the use of the */dev/io* interface.

## PROGRAMMING INTERFACE

All I/O on the **ppi** interface is performed using **ioctl**() calls. Each command takes a single *u\_int8\_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;
	u_int8_t	val;
	val = 0x5a;
	ioctl(fd, PPISDATA, &val);
	ioctl(fd, PPIGCTRL, &val);
	val |= STROBE;
	ioctl(fd, PPISCTRL, &val);
	val &= ~STROBE;
	ioctl(fd, PPISCTRL, &val);
```

## 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.