31.3.3.5.2 Offset Reduction by Sign Chopping

The offset in the conversion result can be reduced using sign chopping. Sign chopping can be used only in accumulating modes (i.e., not in Single mode) in both single-ended and differential conversions, regardless of the PGA being enabled or not.

Sign chopping is enabled by writing a ‘1’ to the Sign Chopping (CHOPPING) bit in the Control F (ADCn.CTRLF) register.