4.13.2.2 WAKE_IN Pin Wake-up

The device may be configured to wake from SLEEP when a valid pulse on the WAKE_IN pin is detected. As specified by the OPEN Alliance TC10 Wake/Sleep specification, pulses with durations of less than 10 µs are ignored while pulses greater than 40 µs in duration are recognized. Recognition of wake pulses between 10 µs and 40 µs is undefined. After determination of a valid pulse, the INH pin is driven high to the VDDAU supply to re-enable external power supplies and wake the system.

Wake-up from detection of a valid WAKE_IN pulse must be enabled by writing a ‘1’ to the WAKE_IN Enable (WKINEN) bit in the Sleep Control 0 (SLPCTL0) register prior to entering the SLEEP state. The assertion level of the detected wake pulse is configured by setting the Wake In Polarity (WIPOL) bit in the Sleep Control 1 (SLPCTL1) register.

Restriction: Assertion of the WAKE_IN pin is only detectable when the device is in the SLEEP state. When awake and in ACTIVE state the device will not detect pulse assertions on the WAKE_IN pin.
Important: When wake from WAKE_IN is enabled, the device will not enter the SLEEP state while the WAKE_IN input is asserted. The WAKE_IN pin must be deasserted before the Sleep Inhibit Delay will occur followed by the INH pin being released and the SLEEP state entered. See Sleep Mode and System Power Management for more details.