I am using ADuC812 for data acquisition system.
I have developed my own pcb.
I am getting a problem with its ADC circuit.
For constant input of 1 volt, it is giving variable output in
ADCDAT register.
The deviation range is about 20H.
I tried with all channels.
Even I tried a Calibration routines which I got with Analog Device
CD.
The problem persists.
I gave the same input to Analog Device Eval kit.
It also give the deviation but not as high as my system.
The deviation range is around 08H.
I want a suggestion for eliminating the devition to
a minimum.

Regards,

Mak Kini.