"I think that this feature may be used to control external watchdog with dummy MOVX/MOVC."

Are you sure, that wasting 18 IOs sounds really like a clever solution to trigger a watchdog ?

Since using MOVC/MOVX cause that P0, P2, P3.6, P3.7 are no longer usable as IO-ports.


Furthermore a crazy program which run out of the internal flash cause the same.

Thus using ALE disable the watchdog in most cases of failure and a pure reset circuit provide exact the same level of reliability by saving cost and pcb space.



Peter