Flavio Rizzardi wrote:

> To summarize, what I (desperately) need is a file that contains
> a schematic drawing for a DIY PIC programmer that can program 16c54
> and 16c73, and the relative software.

Unless you find it fun to build your own programmers (like I do) then
save yourself a lot of hassle and buy one.  If cost is the problem
then you could take Antti's suggestion and look at Robin Abbott's
(FED) design which is available in kit form - FED is UK based.
Another low cost option is the COMPIC-5X programmer from Latvian
company ORMIX Ltd.  Despite your complaint about foreign shipping fees
you might consider the inexpensive programmers from ITU technologies,
Parallax and Newfound Electronics.  All of these companies advertise
on the Web and you can find links here:

http://www.man.ac.uk/~mbhstdj/piclinks.html

Now I've given you some sensible advice I'll answer your question
about a DIY programmer.  I designed my own about 9 months ago mainly
for fun.  My aim was to design a simple parallel port 16C5X/XX
programmer that could be built by hobbyists and one that used no
pre-programmed parts (to be honest this makes the design a little more
complicated than it would be if I designed it around a PIC say).  The
schematic has been on the Web for the last 3 months:

http://www.man.ac.uk/~mbhstdj/upp.html

Up until now I have not made any software available to go with the
design.  The reason is that I just don't have the time to support
potential constructors.  I have had extremely bad experiences with
putting designs on the net in the past.  A couple of years ago I made
a simple 16C84 programmer design available; it isn't a particularly
good design but it works if you build it correctly.  I really didn't
expect people with zero experience to try to build it.  Big mistake.
I am still living with that mistake.

The 5X/XX programmer design is more complicated than the simple 16C84
programmer and I really don't want beginners to waste their time
trying to get it going.  However, there doesn't seem much point in
making the schematic available without providing the necessary
software.  The only thing that makes my design different from some of
the other printer port designs available on the net (like Octavio
Nogueira's/TATO computers ProPic design) is that it can program
parallel-mode PICs.  So, as a compromise I am going to release MS-DOS
software for PIC16C54/55/56/57 programming in source form.  An
experienced hobbyist would be able to modify this for all the other
PICs as it comes with a hex loader, parallel port macros and a set of
microsecond resolution timing routines; these, along with Microchip's
extensive and easy to obtain documentation, give you all you really
need to program any 5X/XX PIC with my hardware.  I will put this stuff
on my WWW site this week.  So start building if you really must make
your own 16C5X programmer but remember my advice above.

Apologies to the PICLIST professionals for the length of this article
but I hope it might be of interest to the many hobbyists on the list.

Cheers,

David
--
david.tait@man.ac.uk
http://www.man.ac.uk/~mbhstdj