33.6 I/O Lines
The I/O lines of the PORT are mapped to pins of the physical device.
The following naming scheme is used: Each line bundle with up to 32 lines is assigned an identifier PORTx, with letter x = A, B, C… Each pin of PORTx is identified by a number n = 0, 1, …31 for the nth pin of that Port. In this way PORT pins are identified as 'Pxn' (for example: PA24, PC3).
Each pin may be controlled by one or more peripheral multiplexer settings, which allow the pad to be routed internally to a dedicated peripheral function. When the setting is enabled, the selected peripheral has control over the output state of the pad, as well as the ability to read the current physical pad state. Refer to the Pinout for additional information.