Hi,

I see lots of mistakes in your code,did you compile your code...

I dont understand what is this....

A1 MOV @DPTR,#31H ;WRITE 1 TO ALL 20 LOCATION


There is no instruction like that it should have been movx @dptr,#31

Its better you go through the this link first...
http://www.8052.com/users/raj...9s8252.pdf

Rgds
Raj Shetgar