Hi all! I m a SY E&C student. And m working on a microcontroller based project.The one i m using is AT89C2051. To test it i wrote a sample program and loaded it in the controller using a universal programmer. The sample program would write a low to P1.3 continuously using an infinite loop. but wen i started the controller after making all the external hardware connections(reset and crystal oscillator , Vcc and GND) instead of showing logic low it gives me +5V only at pin P1.3. Can anybody help me troubleshoot it?
your code is fine
loaded it in the controller using a universal programmer did you use the right chip designation? did you verify? (if your programmer can not read a chip, it is worthless) (reset and crystal oscillator , Vcc and GND) is reset showing not active (look in the datasheet what level that is), is the oscillator running? what you see is (most likely) one of the below: the chip is held in reset the oscillator is not running the chip is not programmed
Erik