P2=0x40;
if(P2==0x80)

It seems you are confused about port I/O. With the code above, P2 can never equal 0x80! Check the "Links" <--- for the 8051 'bible'. It explains the workin of the I/O pins in great detail.

Also, you will make life a lot easier for yourself if you declare the individual port pins that control the ADC's RD, WR and INT pins as sbit variables. It will make your code more efficient and much easier to read.


Hope this helps.

Best regards,
Rob Klein.