                     ======================================
                     Input/Output on hardware ports for DOS
                     ======================================


1 SYNOPSYS
==========

portio lpt?
portio ADDRESS_HEX
portio lpt? VALUE_HEX
portio ADDRESS_HEX VALUE_HEX


2 DESCRIPTION
=============

The `portio' utility can be used to drive the parallel port
or any other hardware device which use the PC ports.

If a lpt ports (lpt1,lpt2,lpt3) or an hexadecimal address is
specified the port is read and the read value is printed on
the screen.

If also a value is specified the port is written with the
specified value.

All the address and all the values are in the hexadecimal
format.

The address of the lpt ports are detected using the BIOS
informations at the memory address 408h.


3 EXAMPLES
==========

Set all the parallel port data bits:

    portio lpt1 ff

Clear all the parallel port data bits:

    portio lpt1 0

Set all bit on the port 80h

    portio 80 ff

Set all the parallel port data bits in the config.sys:

    device=c:\mame\portio.exe lpt1 ff


4 COPYRIGHT
===========

This file is Copyright (C) 2002 Andrea Mazzoleni.
