SAME7 PGA + differential ADC

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Lets say I need a measure voltage across a resistor, the voltage across it is ~0.1v, the voltage at each end of the resistor is 2.95v and 3.05v

 

Ideally I want to do a differential ADC and use the PGA. I would assume that I should be playing with the AOFF register to bias both DACs at around 3v, but I read the following in the datasheet

 

The analog offset of the AFE is configured in the AOFF field in the Channel Offset Compensation register
(AFEC_COCR). The offset is only available in Single-ended mode. The field AOFF must be configured to
512 (mid scale of the DAC) when there is no offset error to compensate.To compensate for an offset error
of n LSB (positive or negative), the field AOFF must be configured to 512 + n.

 

Which seems to indicate that it is not possible for me to do that.

 

Any help would be appreciated.

 

 

Last Edited: Tue. Mar 20, 2018 - 03:49 PM
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