> Next, to increase the transmitter's output, I connected the
> transmitter between RD0 and RD1 on a 18F452 running at 40Mhz
> and wrote some code to generate a 40kHz block. I toggle both
> pic-pins in a single cycle in an attempt to create a pure
> wave as much as possible.

As you are using two pins, you can get a significantly purer sine wave by
_not_ toggling them at the same time.  That will not solve your
read-modify-write problem, but it will reduce wasted power by cutting some
of the harmonics into the transducer.

Nigel
--
Nigel Orr, Design Engineer                 nigel@axoninstruments.co.uk
Axon Instruments Ltd., Wardes Road,Inverurie,Aberdeenshire,UK,AB51 3TT
               Tel:+44 1467 622332 Fax:+44 1467 625235
                   http://www.axoninstruments.co.uk

--
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