There are two different methods for utilizing the wake-up timer (WUT) depending on whether the WUT interrupt is enabled or disabled. If the WUT interrupt is enabled then the nIRQ pin will go low when the timer expires. The chip will also change state to enable the 30MHz XTAL so that the microcontroller clock output is available for the microcontroller to use to process the interrupt. The other method of use is to not enable the WUT interrupt and use the WUT GPIO setting. In this mode of operation the chip will not change state until commanded by the microcontroller. The 32kHz RC oscillator provides an accurate time base compared to other non-crystal based oscillators and can be used to enable wake up events for the MCU as well.