In general, it is recommended to connect unused WKx pins to GND. However, it is possible to leave the unused WKx pins floating, as long as the internal pull-down resistors are enabled by SPI command. If a WKx pins are unused and routed to the connector, it is recommended to keep the corresponding ESD capacitors populated on the board. Important note: If a WKx function is disabled and the device goes to Fail-Safe Mode, the WKx is automatically enabled as one of the wake-up sources. If an unused WKx input is left open without activated pull-down, this input can trigger a wake event, sending the device back to normal mode.