11.3.4.1.2 32.768 kHz Oscillator (OSCULP32K)
The 32.768 kHz oscillator is optimized for Ultra Low-Power (ULP) operation. Power consumption is decreased at the cost of decreased accuracy compared to an external crystal oscillator.
This oscillator provides the 1.024 kHz signal for the Real-Time Counter (RTC), the Watchdog Timer (WDT), and the Brown-out Detector (BOD).
The start-up time of this oscillator is the oscillator start-up time plus four oscillator cycles. Refer to the Electrical Characteristics section for the start-up time.