C8051F93X Datasheet, PDF (164/330 Pages) Silicon Laboratories – Pipelined intstruction architecture executes 70 of instruction in 1 or 2 system clocks

C8051F93x-C8051F92x
14.7. Determining the Event that Caused the Last Wakeup
When waking from idle mode, the CPU will vector to the interrupt which caused it to wake up. When
waking from stop mode, the RSTSRC register may be read to determine the cause of the last reset.
Upon exit from suspend or sleep mode, the wake-up flags in the PMU0CF register can be read to
determine the event which caused the device to wake up. After waking up, the wake-up flags will continue
to be updated if any of the wake-up events occur. Wake-up flags are always updated, even if they are not
enabled as wake-up sources.
All wake-up flags enabled as wake-up sources in PMU0CF must be cleared before the device can enter
suspend or sleep mode. After clearing the wake-up flags, each of the enabled wake-up events should be
checked in the individual peripherals to ensure that a wake-up event did not occur while the wake-up flags
were being cleared.
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