[En-Nut-Discussion] Problem connecting analog sound on port F

[Vincent Timmerman]

Hi,

I want to connect an analog signal to my Ethernut 1.3H board. When I do, the
analog signal turns into noise. When not connected, it's a good signal.
The board I want to connect to my Ethernut, is a standard mic-amp circuit (
http://www.rason.org/Projects/hbmic/mikschem.gif). The circuit works perfect
when it's not connected to ethernut. I connect the output and the ground to
channel0 of the ADC.

To my opinion, this is a hardware problem, because it doesn't matter if the
program is running or not, the output of the opamp gives noise when
connected to Ethernut.
Anyone a clue what I'm missing?

Vincent