35.6.5 Sleep Mode Operation

The Run in Standby bit in Control A register (CTRLA.RUNSTDBY) controls the behavior of the TRNG during standby sleep mode:

When this bit is '0', the TRNG is disabled during sleep, but maintains its current configuration.

When this bit is '1', the TRNG continues to operate during sleep and any enabled TRNG interrupt source can wake up the CPU.