one notic
specific about AT89C52 / AT89S52 .
actually , i dont want to think about that the chip have prob, but chip itself do so !
i have a board of universal remote [rf] in which there are number of relays drive by uln2308, and some opto-couplers ,7-seg display.
my ,prog was ok , but chip was AT89S52 , i surprised that the board not work as it should be [as prog] . then i try to check every think start from power s.
after , this i check board with fresh chip of AT89S , but still a prob is there .
at last i use AT89C :- guess , board work fine.
my brother say me about this ,number of times , but i ignore , and i said to his , dont say something wrong inside the chip .
i think he is right ,