I am designing a simple contact switch(tactile, which conducts when you pushes, and springs back to not-conducting when released) interface with a microcontroller.
It's GPIO has option for both internal pull-up and pull-down.
1) Which one should I use? For 2 layered board, pull-up makes me easier to do PCB artwork, since one-end of switch connects to GND. Other than that, is there any difference or reason for me to use one configuration over another?
2) Is there any possiblity that the noise from physical contact make MCU malfunction?