Hi,
POR_FS means "Power on reset for Fail Safe state machine". It is internal logic signal of FS65 and generate inside FS65. It is the condition for state transition of Main state machine and Fail Safe state machine after power on FS65 with plugging battery.
So POR_FS cannot be triggered by Wake up. "POR_FS" is just the condition for "Wake up" to "Buck or Buck Boost configuration detection Power". If POR_FS is '1', Main state machine will go from "Wake up" to "Buck or Buck Boost configuration detection Power", otherwise it will stay on "Wake up".
BR, Tomas
