Hello,
we would like to refer to the datasheet (section 12.5.6.1) and safety manual (section 11.15.2).
FS1B pin is the secondary safe output pin. FS1B is asserted low with a configurable
delay (tDELAY) or duration (tDUR) when FS0B is asserted low (see Section 12.5.6 in datasheet).
After each power-on reset or after each wake-up event (LPOFF), the FS1B pin is
asserted low. Then the MCU can decide to release the FS1B pin, when the application
is ready to start, which means when no fault is reported/pending and when the fault error counter
is cleared after several good WD refresh (Fault error counter is at "1" at start-up or after
wake-up from LPOFF if no other faults are reported) after RSTB is released from power up.
We hope it helps. Best regards.