23.3.6 Sleep Mode Operation
TCBn is, by default, disabled in Standby sleep mode. It will be halted as soon as the sleep mode is entered.
The module can stay fully operational in the Standby sleep mode if the Run
Standby (RUNSTDBY) bit in the TCBn.CTRLA register is written to ‘1
’.
All operations are halted in Power-Down sleep mode.