What Are GPIO Ports?

General purpose input/output (GPIO) ports are probably the most frequently used way for a microcontroller to contact its environment. A GPIO port can be initialized and used either as an input or output line. A typical example of an output line is one to control a light-emitting
diode (LED). Monitoring a push button or a switch is the function of an input line.

A GPIO port can have either a low (0 volts) or high (a positive voltage, usually 3.3 volts) status. In the .NET Micro Framework, the status of a GPIO port is represented as a Boolean value. The value false corresponds to low status and true to high.