12.6.2.12.3 Entering Standby Mode

There may occur a delay when the device is put into Standby mode, before the power is turned off. This delay is caused by running Clock Generators: if the Run in the Standby bit in the Generator Control register (GENCTRLn.RUNSTDBY) is '0', GCLK must verify that the clock is turned off. The duration of this verification is frequency-dependent.