Hello,
If you have an incorrect value in the ADC, it is likely to be:
- problem with input load,
- wrong clock of ADC.
If you have same thing on the ADC input in both boards, it can eliminate n°1.
For n°2, I would suggest you are checking that the bus speed is really what you expect by enabling ECLK/PTE4. This will output the bus clock on PTE4 and you can make sure you run from the speed you think you are.
These two are the usual mistakes.
Alban.