8.3 Reference Voltages
Some analog peripherals require a reference voltage for proper operation.
Aside from external voltages (i.e., VDDANA), the device provides has a DETREF
module that provides two internal voltage references:
- BANDGAP: a stable voltage reference, refer to the Electrical Characteristics
- INTREF: a variable voltage reference, configured by the Voltage References System Control register in the Supply Controller (SUPC.VREF)
The respective reference voltage source may be selected within the
peripheral's registers:
- ADC: Reference Control register (ADC.REFCTRL)
- AC: Fixed to BANDGAP
- DAC: Reference Selection bits in the Control B register (DAC.CTRLB.REFSEL)