The ports are bi-directional I/O ports with
optional internal pull-ups. The following figure shows a functional description of one
I/O-port pin, here generically called Pxn.
Figure 1. General Digital I/O
Note: WEx, WRx, WPx, WDx, REx, RRx, RPx, and RDx are common to all pins within the same
port. clkI/O, SLEEP are
common to all ports.