

The W5500 Mini is a compact Ethernet controller designed to simplify the process of connecting microcontrollers to the internet. It features an integrated TCP/IP stack, which offloads the complexities of network communication from the microcontroller. This makes it an ideal choice for Internet of Things (IoT) applications, home automation, industrial control systems, and other projects requiring reliable Ethernet connectivity.
The W5500 Mini supports high-speed SPI communication, enabling seamless integration with a wide range of microcontrollers, including popular platforms like Arduino, ESP32, and STM32. Its small form factor makes it suitable for space-constrained designs.








| Parameter | Value |
|---|---|
| Ethernet Standard | IEEE 802.3 10/100 Mbps |
| Communication Interface | SPI (Serial Peripheral Interface) |
| Operating Voltage | 3.3V |
| Logic Level Compatibility | 3.3V |
| Power Consumption | ~132 mA (typical) |
| Integrated Features | TCP/IP stack, 8 independent sockets |
| Buffer Size | 32 KB (shared across sockets) |
| Dimensions | 28mm x 20mm x 5mm |
The W5500 Mini has a standard 8-pin header for SPI communication and power connections. Below is the pinout:
| Pin Number | Pin Name | Description |
|---|---|---|
| 1 | GND | Ground connection |
| 2 | 3.3V | Power supply (3.3V input) |
| 3 | SCK | SPI Clock: Synchronizes data transfer between the microcontroller and W5500 |
| 4 | MISO | SPI Master-In-Slave-Out: Data sent from W5500 to the microcontroller |
| 5 | MOSI | SPI Master-Out-Slave-In: Data sent from the microcontroller to W5500 |
| 6 | CS | Chip Select: Activates the W5500 for SPI communication |
| 7 | INT | Interrupt: Signals events like data reception or transmission completion |
| 8 | RST | Reset: Resets the W5500 to its initial state |
3.3V pin to a regulated 3.3V power source and the GND pin to ground.SCK, MISO, MOSI, and CS pins to the corresponding SPI pins on your microcontroller.INT pin to handle events like incoming data or socket status changes. This is optional but can improve efficiency.RST pin to a GPIO pin on your microcontroller or a manual reset button for resetting the W5500.CS and RST pins for stable operation.Below is an example of how to use the W5500 Mini with an Arduino UNO to establish a basic Ethernet connection.
| W5500 Mini Pin | Arduino UNO Pin |
|---|---|
| GND | GND |
| 3.3V | 3.3V |
| SCK | D13 |
| MISO | D12 |
| MOSI | D11 |
| CS | D10 |
| INT | Not connected |
| RST | Not connected |
#include <SPI.h>
#include <Ethernet.h>
// MAC address for the Ethernet shield
byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };
// IP address for the device (adjust as needed)
IPAddress ip(192, 168, 1, 177);
// Initialize the Ethernet server on port 80
EthernetServer server(80);
void setup() {
// Start serial communication for debugging
Serial.begin(9600);
while (!Serial) {
; // Wait for the serial port to connect (for Leonardo boards)
}
// Start the Ethernet connection
if (Ethernet.begin(mac) == 0) {
Serial.println("Failed to configure Ethernet using DHCP");
// Use static IP if DHCP fails
Ethernet.begin(mac, ip);
}
// Print the assigned IP address
Serial.print("IP Address: ");
Serial.println(Ethernet.localIP());
// Start the server
server.begin();
Serial.println("Server is ready");
}
void loop() {
// Listen for incoming clients
EthernetClient client = server.available();
if (client) {
Serial.println("New client connected");
// Send a basic HTTP response
client.println("HTTP/1.1 200 OK");
client.println("Content-Type: text/html");
client.println("Connection: close");
client.println();
client.println("<!DOCTYPE HTML>");
client.println("<html>");
client.println("<h1>Hello from W5500 Mini!</h1>");
client.println("</html>");
delay(1); // Give the client time to receive the data
client.stop(); // Close the connection
Serial.println("Client disconnected");
}
}
No Ethernet Connection:
Failed to Obtain IP Address:
Unstable Communication:
Interrupt Pin Not Working:
Q: Can I use the W5500 Mini with a 5V microcontroller?
A: Yes, but you must use level shifters for the SPI pins to avoid damaging the W5500, as it operates at 3.3V logic levels.
Q: Does the W5500 Mini support UDP communication?
A: Yes, the W5500 supports both TCP and UDP protocols.
Q: How many simultaneous connections can the W5500 handle?
A: The W5500 supports up to 8 independent sockets for simultaneous connections.
Q: Can I use the W5500 Mini with a Wi-Fi router?
A: Yes, the W5500 Mini can connect to any standard Ethernet network, including those provided by Wi-Fi routers with Ethernet ports.
This concludes the documentation for the W5500 Mini.