42.5.10 Analog Connections
Each comparator has up to four I/O pins that can be used as analog inputs. Each pair of comparators shares the same four pins. These pins must be configured for analog operation before using them as comparator inputs.
Any internal reference source, such as a bandgap voltage reference, OPAMP2,or DAC must be configured and enabled prior to its use as a comparator input.
The analog signals of AC, ADC, DAC and OPAMP can be interconnected. The AC and ADC peripheral can request the OPAMP using an analog ONDEMAND functionality.
See Analog Connections of Peripherals for details.