Addresses that are only locally unique are called locally administered address (LAA) and are marked with U/L = 1. If U/L = 0, the address is valid worldwide as a universally administered address (UAA). Bit 2 (registry): The second bit of the MAC address indicates whether it is an address with global validity (universal) or whether the address has been assigned locally (local).Multicast addresses are identified by I/G = 1 and are addressed to several receivers. If I/G = 0, it is a unicast address for a single network adapter. This bit is called I/G (short for individual/group). Bit 1 (receiver): The first bit of the MAC address specifies whether it is an individual or group address.It should indicate Espressif, as shown i figure 2.įigure 2 – Result of vendor lookup from the ESP8266 MAC.The bit sequence of each MAC address is divided into 4 areas, each of which encodes different information. Just to confirm what was explained in the introduction section, we can check if the first 24 bits of the MAC correspond to the manufacturer of the ESP8266, which is Espressif. You should get something similar to figure 1.įigure 1 – Output of the function to get the MAC of the ESP8266. To test the code, just upload it to the ESP8266 and open the Arduino IDE console. You can check the full working code bellow, which also includes the empty loop function. To get the MAC dress of the ESP8266, we simply call the macAdress method on the WiFi global variable, which will return the MAC address in the hexadecimal format mentioned early. Then, in our setup function, we open the serial port, so we can print the output of our program. Since we only want to print the MAC, we will do all the coding on the setup function and leave the main loop empty.įirst, we include the ESP8266WiFi library, which we typically use to access all the functionality needed for the ESP8266 to connect to a WiFi network. The code for this tutorial is very simple, since we already have a function to get the MAC of the ESP8266. The tests were performed using a NodeMCU board, a very cheap and easy to use ESP8266 board. You can read more about MAC addresses here. The first 24 bits of the MAC are the identifier number of the manufacturer and the second 24 bits are a serial number assigned by the manufacturer. In terms of format, MAC addresses are 48-bit in length and typically represented in hexadecimal format, with each two hexadecimal digits separated by “:”. Taking in consideration the OSI model, MAC addressing works at a layer (layer 2) lower than IP addressing (layer 3). So, MAC addresses are hardware addresses that uniquely identify a network adapter. But, just as a quick explanation, the MAC address is a unique value associated with a network adapter. The objective of this short post is to explain how to get the MAC address of the ESP8266.Įxplaining in detail what is a MAC address is outside of the scope of this post.
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