AVR-Chat

At 12:38 PM 5/11/2004 -0700, Bruce Parham wrote:

>Craig,
>
>I am currently using the code below to run the ADC on an 'M128 with external mux'es to expand
>the system to 42 channels. The whole mess is scanned once per second (without putting the
>cpu to sleep) and I'm only seeing +/- one bit of noise. Each mux input has a 10K/.1uF RC filter
>and all of the filters and mux'es are (SMT) mounted on the top of the board right next to the
>'M128 and are over and connected only to an isolated ground plane (1st inner layer below the top)
>that is connected to the AGND pin. To my amazement, this setup worked so well that I didn't need 
>to do noise canceling.

This is pretty typical in my experience, just beware the "precision" reference on chip.
2.7V for a 2.5V reference, into a 10 bit ADC, is pretty funny, in my opinion.