On Wed, Jun 11, 2008 at 10:42:24PM -0400, M. Adam Davis wrote:
> Better designed internal oscillator, less sensitive to temperature and
> voltage change (perhaps temperature compensated?).
> 
> Don't count on it for RS-232 and other timing applications if you plan
> to run it to its extremes in temperature or voltage - it can vary as
> much as +/-3.2% or so ( see figures 18-39 to 18-42 for graphs) which
> is greater than the 2.5% I usually restrict myself to when talking
> about RS-232 acceptable clock error.
> 
> Still, if you drive it with a reasonable voltage, and stay within a
> restricted temperature range, then it should work reasonably well (ie,
> +/- ~1%).

Right now at 5V and room temp. 9600 buad and 1 minute measurements work well
with the 16F689. I'll soon see how that 1 minute timer works in full sun
shine and using 3AA batteries. Data transmission over serial can occur
in-doors, but hopefully the 1 minute interval won't change too much.

Has any manufacture placed ceramic oscillators in their chip packages
before?

Matthew
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