I understand that P0 is open-drain and does not have an internal pull up resistor. Therefore, when you write a zero to say P0.0 the FET is "on" and pulls the pin low. When you write a 1 the FET is "off" therefore, the pin floats. At HkrMicro he has an LCD and ADC connected to the P0 ports and he says that the LCD provides enough pullup that you dont need to add an external pullup resistor. Is it correct to say then for P0 that either the external devices will provide the pull-up or you add it yourself; therefore, basically it's works the same way as the other ports?