du hast warscheinlich nur die beiden enables vergessen:

Code:
$regfile = "m32def.dat"
$crystal = 8000000
$baud = 9600

Dim Adcwert As Word

Config Adc = Single , Prescaler = Auto

Enable Adc
Enable Interrupts

Start Adc
Do
Adcwert = Getadc(0)
Print "Wert: " ; Adcwert
Waitms 500
Loop
End
Martin