hi... everybody,
would you like to help me about my experiment. I has been made a circuit use the at89c2051 tha I show bellow:
+v bat +v bat
_____
/ ¦ ¦ /
R ¦ ¦ R
/ ¦ ¦ /
¦----¦+ ¦---¦<¦--¦
¦ ¦ ¦ LED
¦-¦- ¦
/ ¦ -----
LDR ¦
/ ¦-+2,5v
¦
0v
I use the comparator input is (+) and (-).
The power supply I use the battery.
I measure the (+)pin is 1.2 volt.
I execute the my program bellow:

LED EQU P1.7

START JNB P3,6,L1
CLR LED
ACALL DELAY
AJMP START
L1 SETB LED
LCALL DELAY
AJMP START
DELAY ....
....
....
RET
END

My question is, why the led sometimes is light?
I thing the comparator output must 0 if input (-)=2.5v and (+)=1.2v.
please help.
thank you very much.

hen