I/O is one of those concepts that can seem self-explanatory. But simple as they may seem, inputs and outputs are a building block of modern electronics.
Inputs and outputs are fundamental to the world of computing (and more generally in data/information processing). Without them, electronic devices of all kinds would have no way of receiving data, and the user would have no way of manipulating or interacting with that data. Since they form the basis of our relationship with almost all the devices we use, it’s important to understand how inputs and outputs function.
What is Input and Output?
Simply put, inputs and outputs are the ways that a computer (or another device) interacts with the world.
Inputs refer to any way that the computer receives data from outside world. The most obvious examples are your computer’s keyboard, trackpad, or mouse, but “inputs” can also include cameras, microphones, and other devices or systems that supply data to a given computer.
Outputs operate similarly, but in reverse. Outputs enable computers to address the physical world; these devices include displays and speakers, but also controls and signals for tasks like turning lights off and on, controlling motors, and more.
How Computer Input and Output Works
Generally, I/O devices communicate with a computer through an interface called a bus. This interface has two main functions.
1. Interpreting. The bus addresses and performs “handshaking” between the devices using basic commands (like “READY” or “BUSY”). This handshaking allows the devices to communicate with each other successfully.
2. Converting. The interface’s second function is to convert data from serial to parallel or vice versa when necessary. This conversion is what allows devices with different types of information to communicate.
Computers and most other digital systems operate in binary, so any input signal must be in binary by the time it arrives at the computer’s processor. Therefore, any analog inputs go through a conversion to digital using an analog-to-digital converter (ADC) – though that is often part of the device/peripheral itself, as in the case of a scanner. The digital signal that results may also need conversion, as mentioned above, since digital data can be either serial or parallel. At this stage, the bus can typically facilitate conversion between types of digital data.
Conversely, an output bus will facilitate the conversion of the computer’s data into whatever form is needed, whether it’s audio, video, or something else. In some cases, such as with audio, digital information will convert back into analog. Users will need to employ a digital-to-analog converter (DAC) to allow the data to be used with real-world devices.
What is GPIO?
A general-purpose input/output (GPIO) is a digital data pin on a circuit (either an integrated circuit or electronic circuit board). A user may change the GPIO’s function at run time and manipulate the pins to operate as inputs or outputs.
Most GPIOs cannot output enough current to power devices like lightbulbs or motors on their own. To use a GPIO to control such a device, you’ll typically need to use a transistor and/or relay to directly power it.
Input and Output Summary
I/O is a broad term that encompasses many different types of auxiliary devices. It is also the concept that governs how humans interact with computers and how computers interact with the world around them. A basic understanding of inputs and outputs can help you approach device construction and manipulation more efficiently and precisely.