In Idle sleep mode, the ZCD will continue to operate as normal.
In Standby sleep mode, the ZCD is disabled by default. If the Run in Standby
(RUNSTDBY) bit in the Control A (ZCDn.CTRLA) register is written to ‘1’,
the ZCD will continue to operate as normal with interrupt generation, event generation, and
ZCD output on pin even if CLK_PER is not running in Standby sleep mode.
In Power Down sleep mode, the ZCD is disabled, including its output to pin.