ok sir i will try it tomorrow. By the way this is the schematic diagram that im using for the project. i have used AT89C52 here because AT89S52 is not available in Proteus(ISIS) which i used to simulate the circuit.and luckily it is working just fine.also the circuit and codes(i posted earlier) is working even if i use AT89C51. can i ask how it is possible? wysiwyg_imageupload:7217:thank alot for helping me