This is a simple light-chasing demo, controlled from the keyboard, in which
the matplc points reflecting the state of the lights are copied onto
some pins of the parallel port. If you wish, you can see these pins change
state with a voltmeter, or build a simple led array to see the lights go on
and off.

The parallel port can sink enough current to light up a led, so you can connect
a led the following way:

+3 to +5 V (you can use two 1,5 V batteries, or a single 4,5 V battery for 
   |        convenience)
   |
   |
  ---
  \ / ->   Led
  ---
   |
   |
  ---
  | |  470 ohm resistor (yellow, violet, brown, gold/silver)
  | |
  ---
   |
   |
 connect to parallel port output pin.   

Mind you, this was the original specification of the parallel port, when it was
built using SSI TTL chips. Your parallel port is most probably implemented
in a LSI chip, so I give no guarantees on what it's current sinking capabilities
are. My parallel port has been working with this configuration for some time 
and has not yet been destroyed, so you may be lucky as well.

With the current config file, the mapping is as follows,
L1 - pin 6
L2 - pin 7
L3 - pin 8
L4 - pin 9

To start:
	cd demo/basic_parport; make

Note - you may have to give the parport driver SUID priviledges, so it can
access the port.

To quit:
	press `Q' on the keyboard


It's controlled from the keyboard (module Kbd, kbd.c): the keys L, R and Q
on the keyboard toggle the three points `left', `right' and `quit'.

The Chaser module (chaser.c) is a primitive `light chasing' program. The
direction of movement can be changed using the `left' and `right' points;
these are notionally push-buttons, but in this demo they are controlled by
the L and R keys. The speed of the chaser can be configured with the
"delay" setting in the "Chaser" section of matplc.conf

The demo terminates when the `quit' point comes on (keyboard Q).


Buglet:
	- assumes a linux terminal (hard coded escape codes).