John Doe wrote about several things, including:
>> ..cut... An RS232 programing board..cut...
>
>Not a whole lot of clues here. Basically any PC based board will work but
>the software is is the issue. At one point in time a long time ago I built
>David Tait's 16C84 programmer for the parallel port and ported the software.
>It worked but was flaky. I bought a PicStart 16B and started using Microchip's
>DOS development system under DOSEMU. It works so well I never really took the
>time to change back.
>
>Honestly I'm partial to the parallel port solution because there are no
>port dependancies required to make it work. Generally the RS-232 programming
>solutions steal power from the port, which doesn't have to gurantee to
>deliver 12V to the board.
>
>..cut..

See David Tait's page http://www.man.ac.uk/~mbhstdj/piclinks.html for
pointers to several parallel and serial types.  He's also got a zipped FAQ
file in there somewhere for people whose programmers don't work.  Parallel
ports on PCs are NOT all the same, the latest IEEE 1284 type can cause
problems - I certainly had some (see
http://www.man.ac.uk/~mbhstdj/kitfix.html).  (Anyone without Web access I
can email details on request.)

While any RS232 unit either has to drive handshake lines to achieve the
desired functions or has to incorporate a control PIC to be a true serial
interface, at least the latter type can be debugged using a simple terminal
emulator.  And a three-line (Tx, Rx, Gnd) serial cable isn't going to have
length or termination problems.

The stand-alone vs independantly powered unit is another issue.
Port-powered has to be the ideal, but to what extent can it be achieved
reliably across ports from a wide range of suppliers?  Anyone got experience?

Tim Forcer              tmf@ecs.soton.ac.uk
Department of Electronics & Computer Science
The University of Southampton, UK

The University isn't responsible for my opinions