help on output port programming

 help on output port programming

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?

 RE: help on output port programming

The sample program ... Can anybody help me troubleshoot it
if somebody could troubleshoot a program they can not see, that would be pure magic.

Till you show the code, nobody can help you

Erik

 RE: help on output port programming

Time for mister ,berik to correct his name before making any more posts. You have spent the last week with this alias - how is it pronounciated?

 hint accepted

and processed

 RE: help on output port programming

Well the problem is, i think with the controller and not with the program.I mean what can b there with a 4-5 line code. Any way the code is
org 0000h
ljmp main
org 0100h
main:
clr p1.3
sjmp main
end

 RE: help on output port programming

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

 RE: help on output port programming

watchdog reset?