Unfortunately the Arduino Digital Pin Tutorial is somewhat misleading ?in that it highlights the Pullup setup for older Arduino Versions in a box and only describes in the text how to do it the new way.
The correct way to enable internal pullup, as Jack has written is:?
pinMode(CAL_BUTTON, INPUT_PULLUP);
but it has to be followed by a
digitalWrite(CAL_BUTTON,HIGH);
to actually connect the internal?pullup resistor to 5V.
