I created a circuit in which all the address inputs of an AT28C256 are connected to outputs of shift registers (74HC164).
In the future I will do many of these circuits, however I haven't yet decided if I need the full 32KB of memory.
Let's just assume that I later decide I need only 8K of memory for my application (for example, AT28C64).
After looking at the datasheets, I notice the difference in pin-out between the two chips is that on the AT28C64, A13 and A14 are replaced with NC (no connects).
Is it OK anyway to connect such pins to outputs of shift registers (and be able to make a AT28C64 like a drop-in replacement for AT28C256) or are the NC pins internally connected to something?
All chips in my question are DIP ICs.