Arduino Ethernet shield: it just won't work!

Question

I have an Arduino Ethernet shield on top of an Arduino Mega2560 and have connected the Mega2560 through serial to my laptop and through the UTP port on the Ethernet shield to my router.

I've tried the "search Arduino on Google" example (where I corrected Google's IP address, the example was old), and it doesn't work (it doesn't seem to connect to the Internet. On the serial, I get: "connecting... /connection failed / disconnecting.").

My UTP cable is working fine... I've tested it on my laptop.

The Mega2560 is connected to my router (which has everything disabled so that's not the problem ) and when I ping from my laptop the IP address I gave the Arduino assembly, it doesn't ping back.

Why? Maybe there is something I'm missing? Here is my code:

Code:

#include <SPI.h>
#include <Ethernet.h>

// Enter a MAC address and IP address for your controller below.
// The IP address will be dependent on your local network:
byte mac[] = {  0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };
byte ip[] = { 192,168,1,177 };
byte server[] = { 209,85,148,147 }; // Google

// Initialize the Ethernet client library
// with the IP address and port of the server
// that you want to connect to (port 80 is default for HTTP):
Client client(server, 80);

void setup() {
  // Start the Ethernet connection:
  Ethernet.begin(mac, ip);
  // Start the serial library:
  Serial.begin(9600);
  // Give the Ethernet shield a second to initialize:
  delay(1000);
  Serial.println("connecting...");

  // If you get a connection, report back via serial:
  if (client.connect()) {
    Serial.println("connected");
    // Make a HTTP request:
    client.println("GET /search?q=arduino HTTP/1.0");
    client.println();
  }
  else {
    // If you didn't get a connection to the server:
    Serial.println("connection failed");
  }
}

void loop()
{
  // If there are incoming bytes available
  // from the server, read them and print them:
  if (client.available()) {
    char c = client.read();
    Serial.print(c);
  }

  // If the server's disconnected, stop the client:
  if (!client.connected()) {
    Serial.println();
    Serial.println("disconnecting.");
    client.stop();

    // Do nothing forevermore:
    for(;;)
      ;
  }
}

Answer 1

The Arduino uses SPI to communicate between the devices. Since the design of the Arduino Mega changed and the older pinout relates to older shields, in order to use it with newer shields you have to hack it a little, to work around the problem.

A lot of people had this question before, and you can still find the answer here: http://mcukits.com/2009/04/06/arduino-ethernet-shield-mega-hack/

Answer 2

For connecting to a server outside your network, you need to include the gateway in Ethernet.begin:

byte dns[] = {8,8,8,8};
byte gateway[] = {192,168,1,1};
Ethernet.begin(mac,ip,dns,gateway);

Answer 3

Check the Ethernet socket on the back road of resistance row, normal value shall be 510 (51Ω)

If it is 511 (510Ω) is a hardware error, replace the normal operation of the correct resistor

Answer 4

Well, in my case the arduino won't communicate because there is a problem with auto negotiation of 10/100mb.

So, I set it to 10mb. And, them it communicate.

I try to use a cat3 cable and it works in same cases. So I decided to use a router where i can set it to 10mb.

Best regards.