At 08:42 AM 5/18/00 -0700, you wrote:

>        I thought I had seen graphs of the stability of the RC mode from
>device to device and over temperature, but I can't locate these in the
>datasheet or app notes.

I don't think that the RC mode is suitable for serial communications,
not in a production product that has to operate over a wide temperature
range.

Why don't you put an SMT or a 20 cent leaded resonator on there? You will get
guaranteed acceptable performance (without a lot of margin, but O.K.)
Resonators are much more robust than crystals.

Only a percent or two change and you will have decreased serial noise
immunity,
at 5% or so it typically will stop working.

I have used LC oscillators on PIC's to improve the guaranteed accuracy, but
the
accuracy certainly not good enough for this application. The stability,
OTOH,
might be just ok for asynchronous serial comms.


Best regards,
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