Great Then ! yes the PC0 and the PC5 are analog pins, so i guess i will just use PC0 and PC3 wich is analog too.
i just did a little research about using internal pull-ups, but i cant see the logic in saving parts, because as far as i understood i will still using 2 push buttons and to resistors.
and the datascheet for the RTC is : http://www.datasheetdir.com/DS1307+download