hello.. i think i haven't explain clearly what i am tring to achieve. i will try my best and hopefully someone can help me... I am using just a simple DC motor.if i send a data string eg '10111' as explained earlier it will cause an interrrupt for the first 2 bits and the rest will be data bits. let say if a '111' is detected as a data it will give a '1' at P2.1. and return back to '0' when there is no data transmitted. let say the data bit that i send was '10101' then it will put a '1' at P2.2 and so on. then i will configure that when there is a '1' at P2.1 it will make both motors move forward. so the main thing that i want to do actually is to read the data when an interrupt happens and put '1' at the port that is being assigned. i hope this will clear things up on what actually i need. i am really sorry of the confusion coz actually english is not my first language.