I did a VERY quick test with some 16c505 and internal
RC osc at 4MHz. Speed variation between chips was less
than 0.5%, and what surprised me was the difference
between 27'C and 40'C was only about 0.5% also!!
I only measured about 5 or 6 chips, and they were
from the same (recent) batch.
-Roman


Rudy Rudy wrote:
>
> If anyone tries this, please post your findings.  I am sure that many
> people here would love to know the outcome.
>
> Rudy
>
> > > quite well (since it is R/C based).  I'm concerned, however, that
> > > it might not perform so well in an environment that experienced
> > > significant temperature variations
> >
> > I doubt that it is. Easy enough to prove - set up a routine that
> outputs
> > a particular frequency or timebase at 20C. Stick the circuit in the
> > freezer for a while and test it when cold, then further test as it
> comes
> > up to room temperature. Or use Instant Freeze and a hot air gun. If
> > it's anything like other RC functions, you may find a 2:1 variation
> > between cold (fast) and hot (slow)

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