Hi Sakri,

only a hint for fault-tolerant programming:

If in your example the variable KB_cnt was above 10, your program hangs forever. Thus, why every switch() statement should also have the "default:" branch to resolve any unexpected states.


For your banking problem you must read the compiler manual, how banking was supported.
Maybe, banking was not supported during interrupts or only the bank 0 must be used during interrupts.


To use 256 bytes XDATA with wrap around, simple use PDATA. Again, how PDATA supported on bank switching can only tell your compiler manual.


On needing big memory, it was always better, to use derivates, which support it without bank switching, e.g.: DS80C390, XA, 251, ...


Peter