Ah, the DIY programmer thread again ...

Oliver Praudisch wrote:
> I'm preparing to build the david tait programmer, has anyone used a bread
> board and wire for this circuit, and are there any problems going this
> route over a pcb?

Actually I have three programmer designs.

I doubt if my simple 16C84 programmer should be your first choice.
Octavio Nogueira's (TATO Computers) hardware is more or less the
same as my "classic" programmer but is enhanced by the addition of
variable VPP capability and comes with Windows software which is
able to program many PICs.  His web site includes a PCB design:

http://www.geocities.com/SiliconValley/Pines/6902/

For playing with the 16C84 (or the 16F84 if you don't need code
protection and embed config info in your source) I still find my
"TOPIC" programmer quite useful.  It is relatively easily
integrated with MPLAB and programs the on-board PIC in-circuit
very quickly.  It comes with a PCB layout.

My "UPP" design is what I use for my own development work with
EPROM-based devices.  It can program all baseline and midrange
PICs but I only supply software for the 16C54/55/56/57.  I don't
supply anything for the others because I can't guarantee the
programming pulse timing shown in Microchip's programming specs (I
don't know how the others do it) although in practice it doesn't
seem to be a problem.  No PCB either.

If you don't want to tie up your printer port (or add another)
then the serial port design(s) by Jens Madsen look quite fun:

http://www.gbar.dtu.dk/~c888600/newpic.htm

and have the advantages that no power supply is required (provided
your serial port is up to it) and construction errors are unlikely
to damage your computer.  Again PCB details are provided.

There are numerous other DIY programmer options (including some
that require a PIC programmer to make!) but I'd better stop here.

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