Dear anybody!

Thanks everybody who is activ in this forum - its a very
good thing!

I need some help.
I'm using the AT89S8252 (80C52 comp.) for developing a microcomputersystem.
During the development I have destroyed the
uC (already 2) - but I can't imagine how.
The destroyed pin is Pin 28 (A15).
It drives just two 74HCT Gates, which select
the RAM (lower 32k) and the ROM (upper 32k).
There are no other components to the pin connected.
I never use the Pin directly, the PIN is used from
the uC during addressing.
I'm sure, that never a voltage higher than 5 V. occured
at the Pin. How can than blow the pin?
(Is it resistant against shorts to GND or VCC?)

Is it possible, to blow such a pin with any software?
I'm using normal code, there is only one funny thing I do:
I have two programs in my uC:
* A boot prog in the internal Code mem
* A main prog in the ROM
I call at one stage from the bootprog the main prog
like a function. The two progs are totally independent and compiled
seperately. (I don't clear the stack and so on)
It seems, after this call, my controller stopped
working - but I can't imagine how this could
blow my A15-Pin.

In general: How could I have blown the Pin
(occured from hardware or software)?

I don't have any glue what to do and would be
so pleased about an answer!

Best Regards

Andreas Schweinzer