Hi friends: I need your help again. I have used Keil c51 to compile my program which has past emulator and simulator test. Right now I am burning AT89C52 chip. In my code I want port P1 to be high, but every time I always get opposite situation. Few pins of P1 port are randomly low. What is wrong, Should P1 port 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 high in my code. Do you have any idea about that? Would let me share your ideas? Thank you and Best Regards.
林先生 您好： 我以收到那份报告。 我正在调试硬件，很奇怪，我的硬件没问题，但软件还是有问题的。 不过别但心，我会尽快解决的。。 祝你身体健康。
So sorry friends. I post a wrong message above. Before running my program, I have burn another example program into AT89C52 which turn on and turn off LED regularly using P1 port. This program works very well on my board. In the beginning of my program, I have set P1 port to be 0xff immediately and P1 port is connected only to a connector which I insert the pins of chip inside. The programmer I have used has the function to verify if the correct data have been burn in. But when my program was burn on, P1 port is not all high. Should AT89C52 reset itself after power on or I have to reset it in the program? Thank you for your generous ideas.
Should AT89C52 reset itself after power on or I have to reset it in the program? Sorry, was just about to answer, but since you refuse to answer questions (as in the "compatible chip" thread post below) why should I? Erik