status: add function works,
        pid function almost works, but not yet. I always assumes a period of ??

  D S P
 =======

This is merely the structure for a dsp processing module. It will
contain sub-module (blocks) such as filters, pid, lag, histeressis,
dead-band, ... These blocks will be interconnected using plc points.

At the moment we only have an adder block (adds two signals) and a
very basic pid block (open loop) that doesn't quite work because I have
not yet gone to the trouble of finishing it (it is only missing the
gettimeofday function call to determine the elapsed time between
two successive calls).

I have not gone to the trouble of finishing it because without 
synching of modules, the pid loop is almost useless, so I'll concentrate
on that first.

In the mean-time, Chetan has promised to write a full-blown PID loop,
but it seems as if he currently tied up with lot's of work, so it will
be some time before it comes on-line.


 Mario.