Why does the falling edge external interrupt always triggering?

Hi everyone, i have met another problem that i am unable to solve for several days. The Falling Edge External Interrupt that i have set INT0 of the DS89C450 MCU is always triggering even when i do not trigger it by pressing the IR remote control.(And it shows 1000 characters of 'F' on the MTK.)

Basically my program is here:
http://pastebin.com/atpb3EZy

 RE: Why does the falling edge external interrupt always triggering?

Do you think people bother to follow random links to retrieve unknown information - especially in a world where the "wrong" link may contain viruses?

Your code to configure the interrupt, and handle the interrupt, just can't be too big for you to post directly in this thread - correctly tagged as source code as clearly described directly above the input message box.

Next thing - people only know what you post in this thread. People don't try to merge information here with potential information posted in some other threads. So you really should describe what you have connected to the interrupt input and what type of signals that gets sent to that input.

You say character "F" in your post. But an external interrupt will most probably not represent any character "F" unless you have implemented a software UART. Have you? Or exactly how do you create or detect that "F" character?

 RE: Why does the falling edge external interrupt always triggering?

Sorry. It is ignorant of me to post an unknown link. About the character "F", i have a case function that converts data of the IR Signals to ASCII code. Character "F" = 0x0F in hex.

However, the problem have been solved because of the hardware not having the common ground with the pcb board.

 RE: Why does the falling edge external interrupt always triggering?

"However, the problem have been solved because of the hardware not having the common ground with the pcb board."

And that is a good example how readers on a forum have a very hard to help when the problem is caused by something that hasn't been described.

 RE: Why does the falling edge external interrupt always triggering?

Basically my program is here:
http://pastebin.com/atpb3EZy

Per WestermarkPosted
Do you think people bother to follow random links to retrieve unknown information - especially in a world where the "wrong" link may contain viruses?

AND Do you think people bother to read through a whole program to find the little section where the issue is

Your code to configure the interrupt, and handle the interrupt, just can't be too big for you to post directly in this thread - correctly tagged as source code as clearly described directly above the input message box.
that would get you a reply