When using any of the device's internal oscillator, there are three power modes available for each oscillator:
- Auto power on (CTRL_SRC = 0 and PWR_MODE = 0): the internal
oscillator is triggered when any macro-cell that requires the oscillator is
running and then power off once the task is complete.
- Force power on (CTRL_SRC = 0 and PWR_MODE = 1): the internal
oscillator continuously runs as long as the device is powered on.
- External power on/off (CTRL_SRC = 1,
CTRL_SEL = 0, and PWR_MODE = 1): a High input into the PDWN input
powers down the oscillator and a Low powers on the oscillator.
These power modes are only applicable when the internal oscillator is selected and is bypassed when an external clock (SRC_SEL = 1) is used.