13.4.1.1 OSC32K Initialization

After a reset, OSC32K is configured by default to run if requested by any peripheral. If no peripheral is requesting OSC32K, the oscillator will be off.

OSC32K requires a start-up time to stabilize on the correct frequency. During the start-up time, the oscillator output is masked to ensure that no unstable clock propagates to the digital logic.

The oscillator can be forced to always run by writing the On-Demand Operation bit in the OSC32K Control register (OSC32KCTRL.ONDEMAND) to ‘0’.

A reset will revert this behavior so that the oscillator will only run if requested by a peripheral.