Help! regarding keypad and microcontroller at89c51

can any one plz guide me how to interface keypad with at89c51 microcontroller i followed the cct diagrame that was given on net but my cct is not detecting any input on keypad and on my lcd there are only black boxes.
plz can any one can guide me.

it is the diagram of my cct, plz if any one can tell me what i m doing worng.

View attachment untitled.bmpView attachment untitled.bmp

The normal way to read the keypad is

set pins connected to A,B,C,D as input with internal pull up,
set pins connected to 1,2,3 as output and low state.
then read which one of A,B,C or D is not 1 anymore, a button in this line is pressed, you have found the line pressed

To find the row apply high to row 1 , if the grounded pin is no longer 0 then the row 1 was pressed
if not apply high to row 2 , if the grounded pin is no longer 0 then the row 2 was pressed
if not apply high to row 3 , if the grounded pin is no longer 0 then the row 3 was pressed or you can assume it was that one since it wasn't one of the other two.

You either have a problem with your code or it is a problem with the internal pull ups (i think your chip has open drain outputs).
You can connect 4 pull up resistors (10K) from Vcc to A,B,C and D and try again.

Alex