thanks to the forum for providing the following reply which when i implemented worked with efficieny.

http://www.8052.com/forum/read.phtml?id=45273

as i was searching the topics which can show how to make controller to do several works at a time i found the many websites suggest two techniques:-

State Machine & Time slicing .

and state machine is recommended..

now can some one please give me some example problem which i can solve to show that i understand the state machine concept of programming. i need some excrises which can slowly help me to learn to make controller do several things at a time but i need some to re-check these examples also.