Re: [avr-gcc-list] ADC anomaly

[Mattias Svensson]

Douglas Dotson wrote:
> All this is on a breadboard right now. When I 
> layout the PCB, all the normal precautions will
> be in place to keep noise to a minimum.

Never underestimate the noise capabilities of a breadboard... ;)

A PCB with proper AGND plane separated from DGND is the only possible 
way. And you should have the AGND plane go under the corner of the 
divice that has the ADC inputs.
AGND and DGND should be linked in a star configuration, and only at one 
point. Preferably at the place you have the main power input to the PCB.

Mattias S