Sorry Mohd Ridzuan Ranjit,,,,I have to work on repairing the mother board in my wifes computer that blew up three of its Aluminum Electrolytic Capacitors this weekend. One cap shorted and made a surface mount regulator so hot that it melted its solder joints and slid nearly 1 cm down the board before killing the computer in its tracks. So I guess you will have to learn a little about programming and translate the ideas I posted into code on your own. Search around...there is lots of code that shows how to program timers....particulary there is the INTEL PCA Cookbook which you can download from the 8052.com Links page. Then there are examples of look up tables used in the code on this sample program that I posted a while back.

http://www.8052.com/users/mkaras/loader.pdf

There are also some lookup tables used in this code that I posted recently.

http://www.8052.com/users/mkaras/Bit_Machine.A51

And the following link has some sample code that shows programming a timer to generate a repeatitive timer interrupt for processing a state machine. The code to implement the 4 msec interrupt ticker like I suggested to you would be structurerd somewhat similar to this sample.

http://www.8052.com/users/mkaras/State_Machine.A51

Michael Karas