libieee1284(3) [debian man page]

LIBIEEE1284(3)							   Introduction 						    LIBIEEE1284(3)

NAME

       libieee1284 - IEEE1284 communications library

SYNOPSIS

	       #include <ieee1284.h>
	       cc files... -lieee1284

OVERVIEW

       The libieee1284 library is a library for accessing parallel port devices.

       The model presented to the user is fairly abstract: a list of parallel ports with arbitrary names, with functions to access them in various
       ways ranging from bit operations to block data transfer in one of the IEEE 1284 sanctioned protocols.

       Although the library resides in user space the speed penalty may not be as bad as you initially think, since the operating system may well
       provide assistance with block data transfer operations; in fact, the operating system may even use hardware assistance to get the job done.
       So, using libieee1284, ECP transfers using DMA are possible.

       The normal sequence of events will be that the application
	1.  calls ieee1284_find_ports to get a list of available ports
	2.  then ieee1284_get_deviceid to look for a device on each port that it is interested in
	3.  and then ieee1284_open to open each port it finds a device it can control on.
	4.  The list of ports returned from ieee1284_find_ports can now be disposed of using ieee1284_free_ports.
	5.  Then when it wants to control the device, it will call ieee1284_claim to prevent other drivers from using the port
	6.  then perhaps do some data transfers
	7.  and then ieee1284_release when it is finished that that particular command. This claim-control-release sequence will be repeated each
	   time it wants to tell the device to do something.
	8.  Finally when the application is finished with the device it will call ieee1284_close.

       Usually a port needs to be claimed before it can be used. This is to prevent multiple drivers from trampling on each other if they both
       want to use the same port. The exception to this rule is the collection of IEEE 1284 Device IDs, which has an implicit
       open-claim-release-close sequence. The reason for this is that it may be possible to collect a Device ID from the operating system, without
       bothering the device with it.

CONFIGURATION

       When ieee1284_find_ports is first called, the library will look for a configuration file, /etc/ieee1284.conf.

       Comments begin with a '#' character and extend to the end of the line. Everything else is freely-formatted tokens. A non-quoted (or
       double-quoted) backslash character '' preserves the literal value of the next character, and single and double quotes may be used for
       preserving white-space. Braces and equals signs are recognised as tokens, unless quoted or escaped.

       The only configuration instruction that is currently recognised is "disallow method ppdev", for preventing the use of the Linux ppdev
       driver.

ENVIRONMENT

       You can enable debugging output from the library by setting the environment variable LIBIEEE1284_DEBUG to any value.

FILES

       /etc/ieee1284.conf
	   Configuration file.

SEE ALSO

       parport(3), parport_list(3), ieee1284_find_ports(3), ieee1284_free_ports(3), ieee1284_get_deviceid(3), ieee1284_open(3), ieee1284_close(3),
       ieee1284_claim(3), ieee1284_release(3), ieee1284_data(3), ieee1284_status(3), ieee1284_control(3), ieee1284_negotiation(3),
       ieee1284_ecp_fwd_to_rev(3), ieee1284_transfer(3), ieee1284_get_irq_fd(3), ieee1284_set_timeout(3)

AUTHOR

       Tim Waugh <twaugh@redhat.com>
	   Author.

COPYRIGHT

       Copyright (C) 2001-2003 Tim Waugh

								    09/18/2007							    LIBIEEE1284(3)

IEEE1284_NEGOTIATION(3) 					     Functions						   IEEE1284_NEGOTIATION(3)

NAME

       ieee1284_negotiate, ieee1284_terminate - IEEE 1284 negotiation

SYNOPSIS

       #include <ieee1284.h>

       int ieee1284_negotiate(struct parport *port, int mode);

       void ieee1284_terminate(struct parport *port);

DESCRIPTION

       These functions are for negotiating to and terminating from IEEE 1284 data transfer modes. The default mode is called compatibility mode,
       or in other words normal printer protocol. It is a host-to-peripheral mode only. There are special modes that allow peripheral-to-host
       transfer as well, which may be negotiated to using ieee1284_negotiate. IEEE 1284 negotiation is a process by which the host requests a
       transfer mode and the peripheral accepts or rejects it. An IEEE 1284-compliant device will require a successful negotiation to a particular
       mode before it is used for data transfer (but simpler devices may not if they only speak one transfer mode).

       To terminate the special mode and go back to compatilibity mode use ieee1284_terminate.

       These functions act on the parallel port associated with port, which must be claimed.

       With a device strictly complying to IEEE 1284 you will need to call ieee1284_terminate in between any two calls to ieee1284_negotiate for
       modes other than M1284_COMPAT.

AVAILABLE MODES

   Uni-directional modes
       o   M1284_COMPAT: Compatibility mode. Normal printer protocol. This is not a negotiated mode, but is the default mode in absence of
	   negotiation.  ieee1284_negotiate(port, M1284_COMPAT) is equivalent to ieee1284_terminate(port). This host-to-peripheral mode is used
	   for sending data to printers, and is historically the mode that has been used for that before IEEE 1284.
       o   M1284_NIBBLE: Nibble mode. This peripheral-to-host mode uses the status lines to read data from the peripheral four bits at a time.
       o   M1284_BYTE: Byte mode. This peripheral-to-host mode uses the data lines in reverse mode to read data from the peripheral a byte at a
	   time.

   Bi-directional modes
       o   M1284_ECP: ECP mode. On entry to ECP mode it is a host-to-peripheral (i.e. forward) mode, but it may be set to reverse mode using
	   ieee1284_ecp_fwd_to_rev(3). It is common for PC hardware to provide assistance with this mode by the use of a FIFO which the host (or,
	   in reverse mode, the peripheral) may fill, so that the hardware can do the handshaking itself.
       o   M1284_EPP: EPP mode. In this bi-directional mode the direction of data transfer is signalled at each byte.

   Mode variations
       o   M1284_FLAG_DEVICEID: Device ID retrieval. This flag may be combined with a nibble, byte, or ECP mode to notify the device that it
	   should send its IEEE 1284 Device ID when asked for data.
       o   M1284_BECP: Bounded ECP is a modification to ECP that makes it more robust at the point that the direction is changed. (Unfortunately
	   it is not yet implemented in the Linux kernel driver.)
       o   M1284_ECPRLE: ECP with run length encoding. In this mode, consecutive data bytes of the same value may be transferred in only a few
	   cycles.

RETURN VALUE

       E1284_OK
	   The negotiation was successful.

       E1284_NOTAVAIL
	   Negotiation is not available with this port type.

       E1284_REJECTED
	   Negotiation was rejected by the peripheral.

       E1284_NEGFAILED
	   Negotiation failed for some reason. Perhaps the device is not IEEE 1284 compliant.

       E1284_SYS
	   A system error occured during negotiation.

       E1284_INVALIDPORT
	   The port parameter is invalid (for instance, perhaps the port is not claimed).

AUTHOR

       Tim Waugh <twaugh@redhat.com>
	   Author.

COPYRIGHT

       Copyright (C) 2001-2003 Tim Waugh

								    09/18/2007						   IEEE1284_NEGOTIATION(3)