****** PARPORT EXAMPLE ******

In this directory you'll find a real-time implementation of a data transfer 
protocol between the standard parallel ports (SPP) of two PCs.
Data can be transferred between such ports via a PC-to-PC parallel cable as the 
standard LapLink, which links five data outputs from one end to the five status 
inputs on the other and vice versa.
Data is transferred four bits at a time using the fifth bits for handshaking 
(nibble mode).

This example was tested with a homemade cable with the following pin-to-pin 
connections:

2 -> 15  bit 0
3 -> 13  bit 1
4 -> 12  bit 2
5 -> 11  bit 3
8 -> 10  handshaking bit

and the reverse

15 -> 2
13 -> 3
12 -> 4
11 -> 5
10 -> 8.

If you use the LapLink cable (the pin-to-pin connection is 2 <-> 15, 3 <-> 13, 
4 <-> 12, 5 <-> 10, 6 <-> 11), you have to set the macro RT_PARPORT_LAPLINK to 
RT_PARPORT_LAPLINK_MODE_D4.

To build the example, type make.

To run the example, type ./sender_run for the sender-PC,
and ./receiver_run for the receiver-PC.

To remove modules, type ./sender_rem or ./receiver_rem respectively.

Report any bugs to Lorenzo Dozio, dozio@aero.polimi.it
