The general purpose input/output (GPIO) peripheral lets the application write data out and read data in through the device pins. Through the use of the Port A GPIO peripheral, these devices support up to 18 GPIO pins.

The key features of the GPIO module include:

• 0 wait state MMR access from CPU
• Set, clear, or toggle multiple bits without the need of a read-modify-write construct in software
• "FastWake" feature enables low-power wakeup from STOP and STANDBY modes for any GPIO port
• User controlled input filtering