17.1 Features
- General Purpose Input and Output Pins with Individual Configuration
 - Output Driver with Configurable Inverted I/O and Pullup
 - Input with Interrupts and Events:
- Sense both edges
 - Sense rising edges
 - Sense falling edges
 - Sense low level
 
 - Asynchronous Pin Change Sensing That Can Wake the Device From all Sleep Modes
 - Efficient and Safe Access to Port
               Pins
- Hardware read-modify-write through dedicated toggle/clear/set registers
 - Mapping of often-used PORT registers into bit-accessible I/O memory space (virtual ports)
 
 
