20.2.2 Peripherals Using Voltage References

Devices in the AVR LA family have a number of peripherals that can use a voltage reference.

• The AC peripheral uses input pins, but the negative input can be routed to use the voltage reference controlled by VREF.AC0REF. In addition, the AC peripheral has its own independent voltage divider for the incoming reference voltage, controlled by the AC0.REFSCALE register.
• The ADC peripheral provides its own control register for the voltage reference and is not selected by VREF. The ADC voltage reference is selected by writing to the Reference Selection (REFSCALE) bit fields in the ADC0.CTRLC register.
  • The ADC can also use the AC reference voltage divider (AC0.REFSCALE) as a positive input