notify when "fn" key is pressed

Posted on 2000-05-04
Last Modified: 2010-08-05
On my laptop computer I have a key named "Fn" (the function key) and I want to make a function that can override the key when it is pressed. How do I do that?
Question by:hypereng
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Expert Comment

ID: 2777210
I would guess that you can't. A standard keyboard does not have this key, therefore there is not a key scan code for it. In the PC keyboard(original) a Micro converts the x-y key matrix into these scan codes, and sends them to another micro on the motherboard (keyboard controller). All PC hardware does it like this, althought these days using different chipsets. In your laptop, the micro that does the keyboard stuff sends different keycodes depending on the state of the Fn Key, therefore it doesn't exist as a key in it's own right, it only modifies other keys codes. Sorry 'bout this, but my opinion is that this can't be done (perhaps the manufacturer can, but they know stuff we dont).

Expert Comment

ID: 2777636
hyp, out of intrest what does this do to the function keys?...

  in al,21h
  or al,2;
  out 21h,al;

Goes in one button then this in the second...

                        in al,21h
                        and al,253;
                       out 21h,al;

When u press them, does the FN key still work?...

Author Comment

ID: 2778369
It seems to be very difficult (maybe impossible) disabling the function key while the assembly stuff doesn't dissable the function key, even though it dissables all the other keys on the keyboard.

Expert Comment

ID: 2778435
so i take it you tried that, and it failed.... I think your right, its impossible :) unless you get code from the people who made the laptop....

Accepted Solution

saulite earned 125 total points
ID: 2787846
You can't handle that key. This key is handled by keyboard itself. For example, if you press [Fn]+[Setup], keyboard sends [Setup] keycode only. Of course you can handle the [Setup] ceycode. This key is made only to decrease the size of keyboard.

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