Hello all!
 
I have a problem. I am programming a PIC. In the program I load a value from portb to the register TANKOD. The value from portb tell me wich button that is pressed down on a keypad. If button 3 is pressed, 3 will be the value of portb.
 
My problem is that the keypad use "negative logic" or something like that. A 0 is a 1 and a 1 is a 0. So i want to invert the register.
 
11111100    =>    00000011
 
 
Any Idea how I can do this in a easy way.
 
 
Tnx    /Andreas Magnusson