Re: [avr-gcc-list] Troubles with ADC on ATMega16

[Larry Barello]

I don't wait at all, but I do make sure I have fairly low input
impedance.  Either a 50k pot (for variable user input) or put a .1uf
capacitor to filter the input signal.  I am never chasing high speed
signals so I just jammed a large capacitor to clean things up.  If I
were trying to do high speed conversion I would use a low offset
buffer to drive the inputs.  If the lines are floating, each channel
will tend to report the same value as the last driven channel - it is
pretty sensitive.

Cheers!

----- Original Message -----
From: "Keith Gudger" <address@hidden>
> I have found that I must wait about 30 us after switching the A/D
input
> channel before starting the A/D converter.  This allows the input to
> settle down.  It all depends on your inputs - how much capacitance
and
> resitance do they have?