Hi my friends.. I have some trouble with my project. I try to communication microcontroller AT89C51 with computers. I didn't use rs 232, but I replacement with NOT gates. sometimes run and sometimes not run, I don't know why???? mybe you have idea???
"I didn't use rs 232, but I replacement with NOT gates. sometimes run and sometimes not run, I don't know why????" What else do you expect?! The computer has an RS-232 port - it is designed to work according to the RS-232 spec. If you connect it to something that is not RS-232, why should it work? It will only ever work by luck.