RE: [avr-gcc-list] ADC anomaly

[Loveny Design]

The value 477 is approx 5% low, which is within spec for the internal
reference. I think your expectations for the ADC are an order of magnitude
too high ;-)

As for your other problem, it is usual for analogue circuits to be given a
few seconds (or even minutes) to reach thermal equilibrium... which is
possibly the cause of that observation.

Regards,
Jon


> -----Original Message-----
> From: address@hidden
> [mailto:address@hidden Behalf Of Douglas Dotson
> Sent: Monday, 16 February 2004 8:03 AM
> To: Douglas Dotson; Richard Urwin; address@hidden
> Subject: Re: [avr-gcc-list] ADC anomaly
>
>
> Things just got even stranger. I measured the
> 1.22v internal reference on channel 31. Measures
> low by 22 counts. Reads 477, should be 499. I'm
> starting to question the usefullness of this ADC
> as 10 bits.
>
> Doug
>