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. While the internal
oscillator is powered off, all pre-dividers and secondary state dividers are in a
paused state.