2.5.5.1.1 Wait for Interrupt

The wait for interrupt instruction, WFI, causes immediate entry to sleep mode unless the wake-up condition is true, see 2.5.5.2.1 Wakeup from WFI or sleep-on-exit. When the processor executes a WFI instruction it stops executing instructions and enters sleep mode. For more information, see 2.5.5.2.2 Wakeup from WFE.