thanks andy

I just did the same way you said

In a51 file

t32 DATA 0x52
PUBLIC t32

in C file extern unsigned char t32;

it is working, really speaking I have tried simillar thing before but there was some problem so thought I have made a mistake so i started from tail.

thanks
it is atleast showing change in t32 value in debug mode of keil.

well On keil web forum i got one more suggestion to use absass.h
i.e.
# define final DBYTE[0x52]
(final is some name )

now here is there a possiblity to some thing like
final=0x01;?
as i want to write at location 0x52


thanks
sachin