I am having issues with communication between two arduino UNOs with attached ethernet shields. One is sending UDP packets every second or so simply saying "Hello world". The other should receive these packets and then print the content to serial console.
Transmitter
#include <SPI.h>
#include <Ethernet.h>
#include <EthernetUdp.h>
byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED }; //Destination MAC address
IPAddress ip(192, 168, 0, 25); //Local IP address
IPAddress destIp(192,168,0,21); //Destination ip address
unsigned int localPort = 5000; // local port to listen on
unsigned int destPort = 5005; //Destination port
EthernetUDP Udp; //Instance of UDP
char message[] = "Hello World!";
/*Initialise the sending of data using UDP over ethernet*/
void setup() {
Serial.begin(9600);
Ethernet.begin(mac,ip); // start the Ethernet and UDP:
Udp.begin(localPort);
}
void loop() {
Udp.beginPacket(destIp, destPort); //Start Packet
Udp.write(message);
Udp.endPacket(); //Close Packet
Serial.println("Message Sent"); //Send Confirmation message
}
Receiver
/*
UDPSendReceive.pde:
This sketch receives UDP message strings, prints them to the serial port
and sends an "acknowledge" string back to the sender
A Processing sketch is included at the end of file that can be used to send
and received messages for testing with a computer.
created 21 Aug 2010
by Michael Margolis
This code is in the public domain.
*/
#include <SPI.h> // needed for Arduino versions later than 0018
#include <EthernetV2_0.h>
#include <EthernetUdpV2_0.h> // UDP library from: bjoern@cs.stanford.edu 12/30/2008
// Enter a MAC address and IP address for your controller below.
// The IP address will be dependent on your local network:
byte mac[] = {
0x90, 0xA2, 0xDA, 0x10, 0x5F, 0x92 };
IPAddress ip(192, 168, 0, 21);
unsigned int localPort = 5005; // local port to listen on
// buffers for receiving and sending data
char packetBuffer[UDP_TX_PACKET_MAX_SIZE]; //buffer to hold incoming packet,
char ReplyBuffer[] = "acknowledged"; // a string to send back
// An EthernetUDP instance to let us send and receive packets over UDP
EthernetUDP Udp;
#define W5200_CS 10
void setup() {
// start the Ethernet and UDP:
Ethernet.begin(mac,ip);
Udp.begin(localPort);
Serial.begin(9600);
}
void loop() {
// if there's data available, read a packet
int packetSize = Udp.parsePacket();
if(packetSize)
{
Serial.print("Received packet of size ");
Serial.println(packetSize);
Serial.print("From ");
IPAddress remote = Udp.remoteIP();
for (int i =0; i < 4; i++)
{
Serial.print(remote[i], DEC);
if (i < 3)
{
Serial.print(".");
}
}
Serial.print(", port ");
Serial.println(Udp.remotePort());
// read the packet into packetBufffer
Udp.read(packetBuffer,UDP_TX_PACKET_MAX_SIZE);
Serial.println("Contents:");
Serial.println(packetBuffer);
// send a reply, to the IP address and port that sent us the packet we received
Udp.beginPacket(Udp.remoteIP(), Udp.remotePort());
Udp.write(ReplyBuffer);
Udp.endPacket();
}
delay(10);
}
Currently the output I'm receiving from the serial console is:
Received packet of size -256
From 0.0.0.0, port 0
Contents:
The TX LED on the transmitter is flashing, as is the orange LED at the RJ45 jack. At the receiver side, only the ACT LED is flashing. I should also point out, one is a regular ethernet shield and one is version 2 so I'm using the newer library for this version.