21.5.5.1.6 PLL Operation in Sleep Modes

The PLL will behave differently in different sleep modes, based on the settings of PLLCTRL.ONDEMAND and PLLCTRL.ENABLE. PLLCTRL.ONDEMAND must be written when PLLCTRL.ENABLE = 0. Otherwise, the write of this bit is ignored. If PLLCTRL.ENABLE = 0, the PLL will always be stopped. For PLLCTRL.ENABLE = 1, the table below is valid:

Table 21-3. PLL Sleep Behavior
CPU ModeON DEMANDSleep Behavior of DFLL48M
Active or Idle0Always run
Active or Idle1Run if requested by a peripheral
Standby0Always run
Standby1Run if requested by a peripheral
Backup0Always OFF
Backup1Always OFF