Using the built-in pull-up resistor w/ pushbutton?

Forum 2005-2010 (read only) Hardware Interfacing
1

Hello,

I know it is needed to use a resistor connected between +5v and a INPUT pin to leave the pin in a known state in order to use a pushbutton.

I've read somewhere in arduino's documentation that it has built-in pull-up resistors for some pins.

Can I use that resistor instead of an external one with a pushbutton?

If so, what I have to do?

Thank you.

Paco.
PS. Sorry for my english. :frowning:

2

this page explains how to use the built in pull-up resistors: http://www.arduino.cc/en/Tutorial/DigitalPins

3

Thank you sir.