> The ports are designed for one purpose only, to communicate, 
> they are not designed for timing purposes.

Could you check the USART / Serial data standards on that one? I'm pretty
sure they are designed for accurate timing. When you set 9600N81 you get a
very specific frequency of pulses from the port. +/- a few percent at worst.

And even parallel ports have maximum and minimum timing requirement. And you
can control the rate of data delivery via the handshaking lines.

A simple circuit that makes use of those timings to program a PIC is of
value.

---
James.
 

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