ppi(4) [xfree86 man page]

PPI(4)							   BSD Kernel Interfaces Manual 						    PPI(4)

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.

BSD
								  January 2, 1998							       BSD

Check Out this Related Man Page

LPT(4)							   BSD Kernel Interfaces Manual 						    LPT(4)

NAME

     lpt -- generic printer device driver

SYNOPSIS

     device ppc
     device ppbus
     device lpt

DESCRIPTION

     The current lpt driver is the port of the original lpt driver to the ppbus(4) system.

     One purpose of this port was to allow parallel port sharing with other parallel devices.  Secondly, inb()/outb() calls have been replaced by
     ppbus function calls.  lpt is now arch-independent thanks to the ppbus interface.	See ppbus(4) for more info about the ppbus system.

     The parallel port bus is allocated by lpt when the printer device is opened and released only when the transfer is completed: either when the
     device is closed or when the entire buffer is sent in interrupt driven mode.

     The driver can be configured to be either interrupt-driven, or to poll the printer.  Ports that are configured to be interrupt-driven can be
     switched to polled mode by using the lptcontrol(8) command.

     Depending on your hardware, extended capabilities may be configured with the lptcontrol(8) command.  With an ECP/ISA port, you can take
     advantage of FIFO and DMA.

     In order to retrieve printer info from /dev/lpt0, just apply the cat command to the device.  If the printer supports IEEE1284 nibble mode and
     has data to send to the host, you will get it.

FILES

     /dev/lpt0			       first parallel port driver

SEE ALSO

     ppbus(4), ppc(4), lptcontrol(8)

HISTORY

     This driver replaces the functionality of the lpa driver, which is now defunct.

BUGS

     There are lots of them, especially in cheap parallel port implementations.

     It is only possible to open a lpt port when a printer is connected and on-line, making it impossible to run lptcontrol(8) when there is no
     printer connected.

     This driver could still stand a rewrite.

BSD
								 February 14, 1999							       BSD

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ppi(4) [xfree86 man page]

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