Hi friends: I need your help again. Right now I am burning AT89C52 chip. In my code I want port P0 to be high, but every time I always get opposite situation. Few pins of P0 port are randomly low. What is wrong, Dose P0 port should be high after resetting? The worst thing is my chip can not receive interrupt even I have set EA, EX1, EX0, IT0 and IT1 to 1 in my code. Do you have any idea about that? Would let me share your ideas? Thank you and Best Regards.