CAN ANYONE EXPLAIN ME CAUSE OF THIS BEHAVIOUR?

I have micro-board with following:
CPU- 80c320
flash-AT29C256(64kx8)
SRAM-HM628128
Crystal:3.686Mhz


(1) The board tested for serial port 0 by programming the flash for
test-programme that echo the char typed
IT RUN OK
(2)Further programme is modified to echo char " B " ,which is written
in ext SRAM loc# 0x0010
It also work ok, but i see activity on higer adress line.

I think there is problem & higher adress should not show any activity.
Whwn we try to read & wirte at multilpe locations problem is there.
And for due to this I am not able to test SRAM ...?