Together the TX and RX lines of a device using serial communication form a serial port through which communication can occur.įigure 3. As you may expect, the TX line is used to for the data to send device, and the RX line is used to receive data. The wiring involved with setting up UART communication is very simple: one line for transmitting data (TX) and one line for receiving data (RX). UART is a form of serial communication because data is transmitted as sequential bits (we’ll get to this in a bit). The first communication protocol we’ll cover is Universal Asynchronous Receiver/Transmitter (UART). These three protocols, UART, SPI, and I 2 C, differ in their implementation, but ultimately serve the same purpose: transferring data at high speeds to any compatible device. Centering devices around a few protocols meant that designers would be able to interact with any device by knowing a few basic concepts about each communication protocols. The electrical engineering community decided to standardize electronics around three communication protocols to ensure device compatibility. Check out the appendix to this tutorial below for articles on these tricks! 3 protocols for device communication: UART, SPI, and I 2 C For the purposes of this tutorial, however, we’ll leave it at just that. Knowledge of converting between bases is also useful because representing numbers in binary often makes for some cool math tricks as well. In software, binary numbers are prefixed with 0b, octal numbers are prefixed with a 0, and hexadecimal numbers are prefixed with a 0x. As you can imagine, it is easier to write out B9 (hexadecimal) than 10111001 (binary). Knowledge of different base number systems is useful because bytes and data are often represented in different ways. Each number system follows the same principal: each digit represents a number of times a power of that base is counted, and the value of each digit can only be between 0 and base-1 inclusive.
Mathematicians give these common number systems names for simplicity-base 2 is binary, base 8 is octal, base 10 is decimal, and base 16 is hexadecimal. We can then say that each digit is a power of 2, which would mean that 10111001 is actually 1 * 2 7 + 0 * 2 6 + 1 * 2 5 + 1 * 2 4 + 1 * 2 3 + 0 * 2 2 + 0 * 2 1 + 1 * 2 0, or 185 in base 10.Īs you can imagine, you can have number systems based on any number! Some common ones in math are base 2, base 8, base 10, and base 16. We know this is the base 2 system because each digit has value 0 through 1. this is called the base 10 system! In the base 10 system, each digit can have the value 0 through 9 (0 through 10-1). Since ones is 10 0, tens is 10 1, hundreds is 10 2, etc. Put together, this means 5 hundreds + 9 tens + 7 ones (500 + 90 + 7)…or five hundred ninety-seven. In the example of 597, the 5 indicates that there are 5 hundreds, the 9 indicates that there are 9 tens, and the 7 indicates that there are 7 ones. Each of the digits occupies a place-value, and the 1 or 0 in that place-value indicates how many times the place-value is counted. Ever heard of bits and bytes? Individually, these 1s and 0s are bits, and when they are in groups of 8, they are called bytes !Ī byte might look something like this: 10111001Īs it turns out, this sequence of eight represents a number the same way a number like 597 represents five hundred ninety-seven. These highs and lows in a digital signal represent 1s and 0s respectively that, when put together in sequence, carry information that can be interpreted by microcontrollers. In a digital signal, data is transferred as a sequence of high to low and low to high switchings that occur very rapidly. Before we discuss communication protocols, we’ll first discuss how these signals are transmitted. Inter-device communication occurs over digital signals. In this tutorial, we hope to introduce the standard communication protocols that electronic devices use and explain each of them in detail using Arduino Uno. With any serious hobby electronics work, you’re bound to run into one or more of the main communication protocols in use, be it when working with different sensors, or with modules such as the ESP8266. Devices need to communicate with each other to relay information about the environment, express changes in their states, or request auxiliary actions be performed. Today we will be discussing Arduino communication protocols. 3 protocols for device communication: UART, SPI, and I2C.