Hi Jens

Thanks for the elaborate reaction. I now realise that I had already found
your code on the web and studied it (and used it to understand uChips
documentation, which would otherwise have been hard).

My programmer uses a 16c84 to generate the +14V and to handle all timing,
so I won't be hindered by most of the problems you describe. Accidently I
once used the 10mS delay routine for the delay between the bits, but beside
a very slow operation I did not notice any unexpected behaviour from the
pic being programmed.

For the PC-to-programmer communication I use rs232 at a modest 19k2 (that's
the highest speed supported by the w3.11 terminal, which I use for
debugging). To avoid overruns I use a handshake for each character send or
received. So far I have had no problems with doing this under a w95 DOS-box
(I'll try plain DOS, NT3.51 and w3.11 when I have finished the host
program). Using a 16c84 might seem overkill, but it allows some nice
touches:
- no host-OS induced timing problems
- multiple programmers on a single rs232 line
- direct comunication with the target using the same serial line
At least, that will be the nice touches when I've finished my little
project....

Anyway, thanks for tips!

Wouter.