> testing 100MHz (the only choice you have for an oscillator at
> these freqencies is external), HS3 was absolutely required

"Crystal-Max" is ticked in Device panel, which is the highest drive

> Have you tried enabling the watchdog timer? You could then test

> you that the code is jumping into the weeds somewhere.

I noticed last night that the program doesn't actually stop. It just
appears to on the scope. When it's putting out 30,000+ pps the
trace on the scope is quite bright because of the pulse density.
When the program "stops" what actually happens is that the
spacing between the pulses goes from 0.0319ms to 4.756ms.
The pulses themselves remain at 60ns. This wasn't apparent
until I used a digital scope, which showed triggering, so I turned
the brightness right up on the analogue scope and adjusted its
trigger. It's still not a definitive answer though - it's unclear whether
the PIC is generating wonky data or the SX is making its own.
What I hope to do in the next couple of days is upgrade my logic
analyser to at least 50MHz so I can get a better idea of what data
is being presented to the SX. Then I'll have a culprit

Thanks for the SRC file

--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics