Thread: dds + pic
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Old May 31st 04, 12:23 AM
Laura Halliday
 
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Default dds + pic

Ken Scharf wrote in message . ..
Has anybody here attempted to use a pic to control a dds chip (and
wrote the software himself)?
(snip...)


Or "herself", as the case may be...sheesh.

My very first attempt in this area was a long time
ago. I built a DDS around a Qualcomm parallel-input
DDS chip but got tired of binary computatin and
soldering diodes into a programming board. So I made
a controller with a shaft encoder, a Basic Stamp
and a serial-to-parallel interface cobbled together
out of 74HC logic. It worked fine.

Don't try to do everything at once. Get basic
functionality first, *then* get fancy. Do you
really need umpteen memories, variable tuning rates,
and so on? Right away? Probably not...

My Q2220 controller manipulated the 24 bit tuning
word directly (the steps were 50 million / 2^24,
about 3 Hz), then the software turned this into a
frequency readout. With modern chips you probably
don't want to do it this way around.

It's not a crime to recycle other peoples' code,
like the mundane and generally boring bit-pushing to
talk to a 44780 LCD controller.

Laura Halliday VE7LDH "Que les nuages soient notre
Grid: CN89mg pied a terre..."
ICBM: 49 16.05 N 122 56.92 W - Hospital/Shafte