The information has become a crucial aspect of human life. Especially in the digital age, humans are always seeking knowledge. What’s the weather today? Who wants to hang out tomorrow? What’s happening in other countries? How do you use a bitmask? Sources of information are plentiful nowadays, and most of modern technology processes information as a means of operation.

Individual bits can carry information as simple as a boolean. Strings of bits can send even more information, such as characters, integers, etc. While it may seem simplistic, these smaller units of data are the foundations of much broader sets of data. A basic LED screen will need to know which pixels to turn on and which ones to keep off, a robotic arm needs to know how many degrees to pivot on command, and a word processor needs to know which characters to display when a key is pressed. All of this information can be encoded as strings of 0’s and 1’s.

With the importance of information processing being ever prevalent, communicating this information is just as necessary. If a temperature sensor detects 80 °F, but your thermostat is set to 73 °F, the sensor has to communicate that information to the thermostat. The thermostat relies on the temperature sensor to perform the task it was designed for. Without that communication link, both devices become relatively useless. Thus, with the advent of the information era, communication systems emerged.

A modern processor uses a variety of communication links to communicate with the rest of the system it works with. GPIO is the most straightforward link. A step up from GPIO but still at the bottom of the ladder is UART. In this section, we learn about UART. However, before we start our discussion about UART, we will learn about some basic terminology on the topic of digital communication.