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ADuC7024 ADC0

Question asked by skwc on Aug 25, 2011
Latest reply on Aug 26, 2011 by MMA

I'm using the ADuC7024 ADC ch 0.  Code is similar to what's in the sample code


ADCON = 0x7E3;

while( !ADCSTA) {  }

y1 = ADCDAT >> 16;


I found ADC output for a 2V input to be about correct; but for 1V input, I only get half the digital counts (see below)

Vref is assumed to be internal 2.5V


2V input     ADC output =  (about) 3260   this is about correct

1.5V input  ADC output = (about) 1950     this is low, should be about 2450

1V input     ADC output = (about) 700     this is only half, should be about 1600


Any info on this non-linearity?  Is my setup incorrect ?