Re: [avr-gcc-list] ADC anomaly

[Richard Urwin]

On Monday 16 Feb 2004 12:53 am, Douglas Dotson wrote:
> Do you mean the internal reference or the reference
> that is selected with the MUX4:0 bits set to 11110?
> I don't see any specs on the accuracy of that voltage.
> I'm not using the internal 2.56v reference due to the
> inaccuracy. I'm using a precision 2.5v external
> reference that appears to be stable to within a couple
> of millivolts.
>
> I understand what you are saying about thermal
> equilibrium. But in this case just tapping the reset
> button wouldn't be cause for the thermal equalibrium
> to
> be upset. Also, the beast has been setting here for
> several hours and hasn't drifted a bit from the
> expected value. Go figure :)

I think there must be 10mV of noise on the analogue power supply around 
reset. Analogue power is separate from digital power, yes? Have you 
tried running the analogue stuff off a battery?

-- 
Richard Urwin