I have seen that ports are always at +5V unless you pull them down to 0(GND?)

You, evidently, need to get a hold of the fundamentals, so it is bible study time

Erik


here are the links to "the bible"
Chapter 1
http://www.semiconductors.philips.com/acrobat/v...ARCH_1.pdf

chapter 2
http://www.semiconductors.philips.com/acrobat/v...UIDE_1.pdf


chapter 3
http://www.semiconductors.philips.com/acrobat/v...WARE_1.pdf