http://www.8052.com/forum/read.phtml?id=138898
well you got it right, starting a new thread.

Is it possible to use p2 for driving led's or connect dip sw to it but not as a addressable peripheral, I only use xdata $0001 and $0002 to drive a lcd display. P2 is AD8-15 which I don’t use.
the answer is "that depends"
What derivative are you using?

With a 'classic' '51 you can, as long as you do not use movx @dptr and have no external code OR data memory.

You need to verify that your chip does not emit on P0 P2 when operating from internal memory (some require a SFR setting not to) but yes, with the right derivative you can use P0 only (no P2 involvement) for memory access as long as you stay below address 0xff.

for a radical suggestion, why not change the LCD drive to 'port driven' and get rid of all these doubts.

Erik

PS: lcd display what does the 'D' in LCD stand for :)