40.6.2.6 ADC Resolution
The ADC supports 8-bit, 10-bit or 12-bit resolution. Resolution can be changed by writing the Resolution bit group in the Control C register (CTRLC.RESSEL). The RESSEL bit group has a specific configuration mode used to support Accumulation or Oversampling and Decimation features. Refer to these specific sections for more details.
By default, the ADC resolution is set to 12 bits. The resolution affects the propagation delay, see also 40.6.2.8 Conversion Timing and Sampling Rate.