Initialization

For basic operation, follow these steps:

Configure the desired input pins in the PORT peripheral.
Select the positive and negative input sources by writing the Positive and Negative Input MUX Selection bit fields (MUXPOS and MUXNEG) in the Mux Control A register (AC.MUXCTRLA).
Optional: Enable the output to pin by writing a '1' to the Output Pad Enable bit (OUTEN) in the Control A register (AC.CTRLA).
Enable the AC by writing a '1' to the ENABLE bit in AC.CTRLA.

During the start-up time after enabling the AC, the output of the AC may be invalid.

The start-up time of the AC by itself is at most 2.5µs. If a internal referance is used, the referance start-up time is normally longer than the AC startup time. The VREF startup time is at most 60 µs.