ESP32 - Ethernet

This tutorial instructs you how to use W5500 Ethernet module to connect ESP32 to Internet or your LAN Network. In detail, we will learn:

How to connect ESP32 to W5500 Ethernet module
How to program ESP32 to make HTTP request via Ethernet
How to program ESP32 to create a simple web server via Ethernet

Hardware Used In This Tutorial

1	×	ESP-WROOM-32 Dev Module
1	×	USB Cable Type-C
1	×	W5500 Ethernet Module
1	×	Ethernet Cable
1	×	Jumper Wires
1	×	Breadboard
1	×	(Recommended) Screw Terminal Expansion Board for ESP32

Or you can buy the following sensor kits:

1	×	DIYables Sensor Kit (30 sensors/displays)
1	×	DIYables Sensor Kit (18 sensors/displays)

Disclosure: some of these links are affiliate links. We may earn a commission on your purchase at no extra cost to you. We appreciate it.

Introduction to W5500 Ethernet module

The W5500 Ethernet module has two interfaces:

RJ45 interface: to connect to router/switch via Ethernet cable
SPI interface: to connect to ESP32 board, including 10 pins:

NC pin: let this pin unconnected.
INT pin: let this pin unconnected.
RST pin: reset pin, connect this pin to the EN pin of ESP32.
GND pin: connect this pin to the ESP32's GND pin.
5V pin: let this pin unconnected.
3.3V pin: connect this pin to the ESP32's 3.3V pin.
MISO pin: connect this pin to the ESP32's SPI MISO pin.
MOSI pin: connect this pin to the ESP32's SPI MOSI pin.
SCS pin: connect this pin to the ESP32's SPI CS pin.
SCLK pin: connect this pin to the ESP32's SPI SCK pin.

image source: diyables.io

Wiring Diagram between ESP32 and W5500 Ethernet module

This image is created using Fritzing. Click to enlarge image

image source: diyables.io

If you're unfamiliar with how to supply power to the ESP32 and other components, you can find guidance in the following tutorial: How to Power ESP32.

ESP32 code for Ethernet Module - Making HTTP request via Ethernet

The following code functions as a web client, making HTTP requests to the web server at http://example.com/.

/* * This ESP32 code is created by esp32io.com * * This ESP32 code is released in the public domain * * For more detail (instruction and wiring diagram), visit https://esp32io.com/tutorials/esp32-ethernet */ #include <SPI.h> #include <Ethernet.h> // replace the MAC address below by the MAC address printed on a sticker on the Arduino Shield 2 byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xEF }; EthernetClient client; int HTTP_PORT = 80; String HTTP_METHOD = "GET"; // or POST char HOST_NAME[] = "example.com"; String PATH_NAME = "/"; void setup() { Serial.begin(9600); delay(1000); Serial.println("ESP32 - Ethernet Tutorial"); // initialize the Ethernet shield using DHCP: if (Ethernet.begin(mac) == 0) { Serial.println("Failed to obtaining an IP address"); // check for Ethernet hardware present if (Ethernet.hardwareStatus() == EthernetNoHardware) Serial.println("Ethernet shield was not found"); // check for Ethernet cable if (Ethernet.linkStatus() == LinkOFF) Serial.println("Ethernet cable is not connected."); while (true) ; } // connect to web server on port 80: if (client.connect(HOST_NAME, HTTP_PORT)) { // if connected: Serial.println("Connected to server"); // make a HTTP request: // send HTTP header client.println(HTTP_METHOD + " " + PATH_NAME + " HTTP/1.1"); client.println("Host: " + String(HOST_NAME)); client.println("Connection: close"); client.println(); // end HTTP header while (client.connected()) { if (client.available()) { // read an incoming byte from the server and print it to serial monitor: char c = client.read(); Serial.print(c); } } // the server's disconnected, stop the client: client.stop(); Serial.println(); Serial.println("disconnected"); } else { // if not connected: Serial.println("connection failed"); } } void loop() { }

Quick Instructions

If this is the first time you use ESP32, see how to setup environment for ESP32 on Arduino IDE.
Do the wiring between the Ethernet module and ESP32 as the above wiring diagram
Connect the ESP32 to PC via an USB cable
Connect the Ethernet module to your router/switch via an Ethernet cable
Open Arduino IDE on your PC.
Select the right ESP32 board (e.g. ESP32 Dev Module) and COM port.
Click to the Libraries icon on the left bar of the Arduino IDE.
Search “Ethernet”, then find the Ethernet library by Various
Click Install button to install Ethernet library.

Open Serial On Arduino IDE
Copy the above code and paste it to Arduino IDE
Click Upload button on Arduino IDE to upload code to ESP32
Check out the result on Serial Monitor, it looks like below:

COM6

Send

ESP32 - Ethernet Tutorial Connected to server HTTP/1.1 200 OK Accept-Ranges: bytes Age: 208425 Cache-Control: max-age=604800 Content-Type: text/html; charset=UTF-8 Date: Fri, 12 Jul 2024 07:08:42 GMT Etag: "3147526947" Expires: Fri, 19 Jul 2024 07:08:42 GMT Last-Modified: Thu, 17 Oct 2019 07:18:26 GMT Server: ECAcc (lac/55B8) Vary: Accept-Encoding X-Cache: HIT Content-Length: 1256 Connection: close <!doctype html> <html> <head> <title>Example Domain</title> <meta charset="utf-8" /> <meta http-equiv="Content-type" content="text/html; charset=utf-8" /> <meta name="viewport" content="width=device-width, initial-scale=1" /> </head> <body> <div> <h1>Example Domain</h1> <p>This domain is for use in illustrative examples in documents. You may use this domain in literature without prior coordination or asking for permission.</p> <p><a href="https://www.iana.org/domains/example">More information...</a></p> </div> </body> </html> disconnected

Autoscroll Show timestamp

Clear output

9600 baud

Newline

※ NOTE THAT:

If there is another device on the same local network with the same MAC address, it might not work.

ESP32 code for Ethernet Module - Web Server

The following code transforms the ESP32 into a web server that responds to web browsers with a simple webpage.

/* * This ESP32 code is created by esp32io.com * * This ESP32 code is released in the public domain * * For more detail (instruction and wiring diagram), visit https://esp32io.com/tutorials/esp32-ethernet */ #include <SPI.h> #include <Ethernet.h> // replace the MAC address below by the MAC address printed on a sticker on the Arduino Shield 2 byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xEF }; EthernetServer server(80); void setup() { Serial.begin(9600); delay(1000); Serial.println("ESP32 - Ethernet Tutorial"); // initialize the Ethernet shield using DHCP: if (Ethernet.begin(mac) == 0) { Serial.println("Failed to obtaining an IP address"); // check for Ethernet hardware present if (Ethernet.hardwareStatus() == EthernetNoHardware) Serial.println("Ethernet shield was not found"); // check for Ethernet cable if (Ethernet.linkStatus() == LinkOFF) Serial.println("Ethernet cable is not connected."); while (true) ; } server.begin(); Serial.print("ESP32 - Web Server IP Address: "); Serial.println(Ethernet.localIP()); } void loop() { // listen for incoming clients EthernetClient client = server.available(); if (client) { Serial.println("new client"); // an HTTP request ends with a blank line bool currentLineIsBlank = true; while (client.connected()) { if (client.available()) { char c = client.read(); Serial.write(c); // if you've gotten to the end of the line (received a newline // character) and the line is blank, the HTTP request has ended, // so you can send a reply if (c == '\n' && currentLineIsBlank) { // send a standard HTTP response header client.println("HTTP/1.1 200 OK"); client.println("Content-Type: text/html"); client.println("Connection: close"); // the connection will be closed after completion of the response client.println(); client.println("<!DOCTYPE HTML>"); client.println("<html>"); client.println("<body>"); client.println("<h1>ESP32 Web Server with Ethernet</h1>"); client.println("</body>"); client.println("</html>"); break; } if (c == '\n') { // you're starting a new line currentLineIsBlank = true; } else if (c != '\r') { // you've gotten a character on the current line currentLineIsBlank = false; } } } // give the web browser time to receive the data delay(1); // close the connection: client.stop(); Serial.println("client disconnected"); } }