/ 
Device-ParallelPort-1.00
River stage one • 5 direct dependents • 5 total dependents
/ Device::ParallelPort

NAME

Device::ParallelPort - Parallel Port Driver for Perl

SYNOPSIS

my $port = Device::ParallelPort->new();
$port->set_bit(3,1);
print $port->get_bit(3) . "\n";
print ord($port->get_byte(0)) . "\n";
$port->set_byte(0, chr(255));

DESCRIPTION

A parallel port driver module. This module provides an API to all parallel ports, by providing the ability to write any number of drivers. Modules are available for linux (both directly and via parport), win32 and a simple script version.

NOTE - This actual module is a factory class only - it is used to automatically return the correct class and has not other intelligence / purpose.

DRIVER MODULES

NOTE - You MUST load one of the drivers for your operating system before this module will correctly work - they are in separate CPAN Modules.

L<Device::ParallelPort::drv::linux> - Direct hardware access to a base address.
L<Device::ParallelPort::drv::parport> - Linux access to /dev/parport drivers
L<Device::ParallelPort::drv::script> - Run a script with parameters
L<Device::ParallelPort::drv::dummy_byte> - Pretending byte driver for testing
L<Device::ParallelPort::drv::dummy_bit> - Pretending bit driver for testing
L<Device::ParallelPort::drv::win32> - Windows 32 DLL access driver

DEVICE MODULES

L<Device::ParallelPort::Printer> - An example that can talk to a printer
L<Device::ParallelPort::JayCar> - Simple JayCar electronics latched, addressable controller
L<Device::ParallelPort::SerialFlash> - SerialFlash of bits - useful for many driver chips

METHODS

new

CONSTRUCTOR

new ( DRIVER )

Creates a Device::ParallelPort.

METHODS

get_bit( BITNUMBER )

You can get any bit that is supported by this particular driver. Normally you can consider a printer driver having 3 bytes (that is 24 bits would you believe). Don't forget to start bits at 0. The driver will most likely croak if you ask for a bit out of range.

get_byte ( BYTENUMBER )

Bytes are some times more convenient to deal with, certainly they are in most drivers and therefore most Devices. As per get_bit most drivers only have access to 3 bytes (0 - 2).

set_bit ( BITNUMBER, VALUE )

Setting a bit is very handy method. This is the method I use above all others, in particular to turn on and off rellays.

set_byte ( BYTENUMBER, VALUE )

Bytes again. Don't forget that some devices don't allow you to write to some locations. For example the stock standard parallel controller does not allow you to write to the status entry. This is actually a ridiculous limitation as almost all parallel chips allow all three bytes to be inputs or outputs, however drivers such as linux parallel port does not allow you to write to the status byte.

NOTE - VALUE must be a single charachter - NOT an integer. Use chr(interger).

get_data ( )
set_data ( VALUE )
get_control ( )
set_control ( VALUE )
get_status ( )
set_status ( VALUE )

The normal parallel port is broken up into three bytes. The first is data, second is control and third is status. Therefore for this reason these three bytes are controlled by the above methods.

LIMITATIONS

Lots... This is not a fast driver. It is designed to give you simple access to a very old device, the parallel chip. Don't, whatever you do, use this for drivers that need fast access.

DISCUSSIONS

Hardware

Following is the standard hardware table, so that you can find the correct pins and information. Note also the Inverted flag.

A number of real projects have been produced using Device::ParallelPort. For futher information see http://linux.dd.com.au/quest/os-perl/parallelport/

Pin No (DB25) - Signal name - Direction - Register - bit - Inverted

1 - nStrobe - Out - Control-0 - Yes

2 - Data0 - In/Out - Data-0 - No

3 - Data1 - In/Out - Data-1 - No

4 - Data2 - In/Out - Data-2 - No

5 - Data3 - In/Out - Data-3 - No

6 - Data4 - In/Out - Data-4 - No

7 - Data5 - In/Out - Data-5 - No

8 - Data6 - In/Out - Data-6 - No

9 - Data7 - In/Out - Data-7 - No

1 - 0 nAck - In - Status-6 - No

1 - 1 Busy - In - Status-7 - Yes

1 - 2 Paper-Out - In - Status-5 - No

1 - 3 Select - In - Status-4 - No

1 - 4 Linefeed - Out - Control-1 - Yes

1 - 5 nError - In - Status-3 - No

1 - 6 nInitialize - Out - Control-2 - No

1 - 7 nSelect-Printer - Out - Control-3 - Yes

18-25 - Ground

BUGS

Not known yet. Windows support is new so expect some.

TODO

Refer to TODO list with packages and code.

HISTORY

History here covers central Device::ParallelPort and not the specific drivers, see them individually. For full history see Changes in the package.

0.04 - First release

Basic first release. Worked for Linux ROOT and Linux parport drivers only. Windows work only in early pre-alpha testing.

1.00 - First stable release

Stable - I beleive it is stable, but this is only on my own testing and machines. Lots of imporvements to documentation, auto load modules etc. Improved use of perl. In particular this is the first release of Windows and a fully working auto driver.

COPYRIGHT

Copyright (c) 2002,2003,2004 Scott Penrose. All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

AUTHOR

Scott Penrose scottp@dd.com.au, http://linux.dd.com.au/

SEE ALSO

Device::ParallelPort::drv for developing a driver.