---
title: "Communication issues with W5500"
url: "https://maker.wiznet.io/forum/14685"
markdown_url: "https://maker.wiznet.io/forum/14685/md"
type: "Forum topic"
category: "Ethernet Chips"
author: "NLawc"
created: "2022-10-18T21:48:02+09:00"
last_activity: "2022-10-24T17:50:50+09:00"
language: "en"
views: 938
replies: 5
source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)"
---

# Communication issues with W5500

## Question

Asked by NLawc on 2022-10-18 in Ethernet Chips.

Hello,

I’m having difficulty communicating with the chip via web server with Atmega 328pb. Server code below.

```
#define __AVR_ATmega328PB__
#include "Ethernet.h"

#include "C:/Users/user/source/Workspaces/directory/Directory/Libraries/SPI_Atmega_328PB/SPI/src/SPI.h"

//#include <SPI.h>

byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };
//the IP address for the shield:
IPAddress ip(192, 168, 50, 252 );
// the router's gateway address:
//IPAddress gateway(192, 168, 50, 1);
// the subnet:
//IPAddress subnet( 255, 255, 0, 0 );

EthernetServer server(80);

String readString;

void setup()
{
	Serial.begin(9600);
	while(!Serial) {};
	// initialize the ethernet device
	
	Ethernet.init(PIN_SPI_SS);
	
	Ethernet.begin(mac, ip);
	//Ethernet.setLocalIP(ip);
	Serial.println(Ethernet.localIP());
	
	// Check for Ethernet hardware present
	if (Ethernet.hardwareStatus() == EthernetNoHardware) {
		Serial.println("Ethernet shield was not found.  Sorry, can't run without hardware. :(");
		while (true) {
			delay(1); // do nothing, no point running without Ethernet hardware
		}
	}
	if (Ethernet.linkStatus() == LinkOFF) {
		Serial.println("Ethernet cable is not connected.");
	}
	
	// start listening for clients
	server.begin();
	Serial.println("Server is at: ");
	Serial.print(Ethernet.localIP());

}

void loop()
{
	// Create a client connection
	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();
				
				//read char by char HTTP request
				if (readString.length() < 100) {
					//store characters to string
					readString += c;
					Serial.print(c);
				}

				//if HTTP request has ended
				if (c == '\n' && currentLineIsBlank) {
					/*
					Serial.println(readString); //print to serial monitor for debuging
					
					client.println("HTTP/1.1 200 OK"); //send new page
					client.println("Content-Type: text/html");

					client.println("Connection: close");  // the connection will be closed after completion of the response
					client.println("Refresh: 5");  // refresh the page automatically every 5 sec

					client.println();
					
					
					client.println("<!DOCTYPE HTML>");
					
					
					client.println("<html>");
					client.println("<HEAD>");
					client.println("<meta name='apple-mobile-web-app-capable' content='yes' />");
					client.println("<meta name='apple-mobile-web-app-status-bar-style' content='black-translucent' />");
					
					client.println("<TITLE>hello world</TITLE>");
					client.println("</HEAD>");
					client.println("<BODY>");
					client.println("<H1></H1>");
					client.println("<hr />");
					client.println("<br />");
					client.println("<H2></H2>");
					client.println("<br />");
					client.println("<a href=\"/?button1on\"\">Turn On LED</a>");
					client.println("<a href=\"/?button1off\"\">Turn Off LED</a><br />");
					client.println("<br />");
					client.println("<br />");
					//client.println("<a href=\"/?button2on\"\">Rotate Left</a>");
					//client.println("<a href=\"/?button2off\"\">Rotate Right</a><br />");
					client.println("<p></p>");
					client.println("<br />");
					client.println("</BODY>");
					client.println("</html>");
					break;
					*/
					 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("Refresh: 5");  // refresh the page automatically every 5 sec
					 client.println();
					 client.println("<!DOCTYPE HTML>");
					 client.println("<html>");
					 // output the value of each analog input pin
					 for (int analogChannel = 0; analogChannel < 6; analogChannel++) {
						 int sensorReading = analogRead(analogChannel);
						 client.print("analog input ");
						 client.print(analogChannel);
						 client.print(" is ");
						 client.print(sensorReading);
						 client.println("<br />");
					 }
					 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;
				}
				
				//controls the Arduino if you press the buttons
				if (readString.indexOf("?button1on") > 0)
				{
					
				}
				if (readString.indexOf("?button1off") > 0)
				{
					
				}
				if (readString.indexOf("?button2on") > 0)
				{
					
				}
				if (readString.indexOf("?button2off") > 0)
				{
					
				}
				
				//Clear readString for next read
				readString = "";
			}
		}
		// give the web browser time to receive the data
		delay(1);
		// close the connection:
		client.stop();
		Serial.println("client disconnected");
	}
}
```

[![image](https://maker.wiznet.io/forum_uploads/wiznet/original/2X/7/7bbaf963c9c1ed89ddc424d2189df39ccc25dc33.png) image1068×489 86.7 KB](https://maker.wiznet.io/forum_uploads/wiznet/original/2X/7/7bbaf963c9c1ed89ddc424d2189df39ccc25dc33.png)

## Replies

### Reply 1 by Eugeny, 2022-10-18

Not looking at the code much: 0xdeadbeeffeed is locally administered MAC address! Why people keep selecting it?
Next, explain how the difficulty exhibits itself. More detailed explanation will lead to quicker and effective solution.

### Reply 2 by NLawc, 2022-10-24 (in reply to reply 1)

Hey, no problem Eugeny. This is the stock server code mostly. I would just like to get this working for validation purposes. List of system components below:
uC: basic I/O nothing special. SPI bus communications works as expected. Can pass commands to W5500 and receive expected results.
Network Switch: Local network. Network Switch shows activity and speed as expected.

If I configured the system as DHCP the W5500 is seen in the router’s DHCP pool.

### Reply 3 by Eugeny, 2022-10-24

What is the *difficulty* you are experiencing? Can you explain it please?
And change MAC address to something different not having two lower bits in first octet set.

### Reply 4 by NLawc, 2022-10-24

I’m having issues receiving data from the network. The W5500 can communicate via SPI with the main uC.

### Reply 5 by Eugeny, 2022-10-24

Much better! Now explain what issues are you having with the receiving: what you are sending to the W5500, what it displays in debug output, and what it, from your opinion, does wrong.

---

Source: https://maker.wiznet.io/forum/14685