General Purpose Input/Output

General (GPIO) is a acronym of General Purpose Input/Output.

A microprocessor, microcontroller or interface device may have one or more GPIO connections, to interface with the outside world.

These can act as input, to read digital signals from other parts of a circuit, or output, to control or signal to other devices.

GPIOs are often arranged into groups, typically of 8 pins, a GPIO port that usually have individual GPIOs individually configurable either as input or outputs.

Reading or writing one or more control registers reads or writes, or configures the direction of each GPIO.

In some cases, GPIOs may be configurable to produce CPU interrupts and be able to use Direct Memory Access to move large quantities of data efficiently into or out of the device.

GPIO peripherals vary very widely.In some cases, they are very simple, a group of pins that can be switched as a group to either input or output.

In others, each pin can be setup flexibly to accept or source different logic voltages, with configurable drive strengths and pull up/downs.

The input and output voltages are typically, though not universally limited to the supply voltage of the device with the GPIOs on, and may be damaged by greater voltages.

Some GPIOs have 5V tolerant inputs - even on low supply voltages (2V), the device can accept 5V without damage.

ee also

*SGPIO
*I2C
*Serial Peripheral Interface Bus