In stop mode all GPIO pins will be frozen. Can I change the pin status, after waking up from stop mode by a wake up reset?
After a wakeup reset, the GPIO states remain frozen, and must be unfrozen using the API function CySysPmUnfreezeIo() before the pin states can be changed.
Just adding one more point to this....It is not required to call CySysPmFreezeIo for Stop Mode, but is required for Hibernate Mode. If not , the IO-cells will be frozen in the same way as they are in the Active to Deep Sleep transition, but will lose their state on wake up (because of the reset occurring at that time).