GPIO

The digital pins are accessed by using digitalWriteFast(pin,level) and digitalReadFast(pin). Of course, you can also use the slower digitalRead and digitalWrite functions but other than compatibility to Arduino code there is no advantage.

On the pinout cards the digital pins are shown with gray numbers. Additional info about the pinouts can be found here.

Internally, digital input or output is handled by the GPIO (general purpose input / output) module which is not identical but very similar between the various boards.

In depth information about the GPIO system can be found here:

• Setting Pin Modes
• Pin Interrupts
• Low Level Access
• Mapping Pins to Ports
• Alternate Functions