36.5.4 Selecting the Conversion Trigger Source
Class 2 inputs to the ADC module can be triggered for conversion either individually or as part of a scan sequence. Class 3 inputs can only be triggered as part of a scan sequence. Individual or scan triggers can originate from an event system (EVSYS), from external digital circuits connected to INT0, from external analog circuits connected to an analog comparator or through software by setting a trigger bit in an SFR.