-----------------------------以下為參考文件
來源網址:https://www.arduino.cc/en/Tutorial/DhcpChatServer
This example connects to a Telnet server using an Ethernet shield. Messages from the server are printed out via the serial port. Messages can be sent to the remote server serially as well. The Serial monitor works well for this purpose.
This version attempts to get an IP address using DHCP. An IP address can be assigned via DHCP when Ethernet.begin(mac) is called. Be careful, when using the DHCP extensions, sketch size increases significantly.
Arduino or Genuino Board
A telnet server
Alternatively, Processing has a ChatServer example that works well for this purpose
The Ethernet shield allows you to connect a WizNet Ethernet controller to the Arduino or Genuino boards via the SPI bus. It uses pins 10, 11, 12, and 13 for the SPI connection to the WizNet. Later models of the Ethernet shield also have an SD Card on board. Digital pin 4 is used to control the slave select pin on the SD card.
The shield should be connected to a network with an ethernet cable. You will need to change the network settings in the program to correspond to your network.
image developed using Fritzing. For more circuit examples, see the Fritzing project page
In the above image, the Arduino or Genuino board would be stacked below the Ethernet shield.
/*
DHCP Chat Server
A simple server that distributes any incoming messages to all
connected clients. To use, telnet to your device's IP address and type.
You can see the client's input in the serial monitor as well.
Using an Arduino Wiznet Ethernet shield.
THis version attempts to get an IP address using DHCP
Circuit:
* Ethernet shield attached to pins 10, 11, 12, 13
created 21 May 2011
modified 9 Apr 2012
by Tom Igoe
modified 02 Sept 2015
by Arturo Guadalupi
Based on ChatServer example by David A. Mellis
*/
#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.
// gateway and subnet are optional:
byte mac[] = {
0x00, 0xAA, 0xBB, 0xCC, 0xDE, 0x02
};
IPAddress ip(192, 168, 1, 177);
IPAddress myDns(192,168,1, 1);
IPAddress gateway(192, 168, 1, 1);
IPAddress subnet(255, 255, 0, 0);
// telnet defaults to port 23
EthernetServer server(23);
boolean gotAMessage = false; // whether or not you got a message from the client yet
void setup() {
// Open serial communications and wait for port to open:
Serial.begin(9600);
// this check is only needed on the Leonardo:
while (!Serial) {
; // wait for serial port to connect. Needed for native USB port only
}
// start the Ethernet connection:
Serial.println("Trying to get an IP address using DHCP");
if (Ethernet.begin(mac) == 0) {
Serial.println("Failed to configure Ethernet using DHCP");
// initialize the Ethernet device not using DHCP:
Ethernet.begin(mac, ip, myDns, gateway, subnet);
}
// print your local IP address:
Serial.print("My IP address: ");
ip = Ethernet.localIP();
for (byte thisByte = 0; thisByte < 4; thisByte++) {
// print the value of each byte of the IP address:
Serial.print(ip[thisByte], DEC);
Serial.print(".");
}
Serial.println();
// start listening for clients
server.begin();
}
void loop() {
// wait for a new client:
EthernetClient client = server.available();
// when the client sends the first byte, say hello:
if (client) {
if (!gotAMessage) {
Serial.println("We have a new client");
client.println("Hello, client!");
gotAMessage = true;
}
// read the bytes incoming from the client:
char thisChar = client.read();
// echo the bytes back to the client:
server.write(thisChar);
// echo the bytes to the server as well:
Serial.print(thisChar);
Ethernet.maintain();
}
}
--------------------------
Reference Language | Libraries | Comparison | Changes
Description
Initializes the ethernet library and network settings.
With version 1.0, the library supports DHCP. Using Ethernet.begin(mac) with the proper network setup, the Ethernet shield will automatically obtain an IP address. This increases the sketch size significantly. To make sure the DHCP lease is properly renewed when needed, be sure to call Ethernet.maintain() regularly.
Syntax
Ethernet.begin(mac);
Ethernet.begin(mac, ip);
Ethernet.begin(mac, ip, dns);
Ethernet.begin(mac, ip, dns, gateway);
Ethernet.begin(mac, ip, dns, gateway, subnet);
Parameters
mac: the MAC (Media access control) address for the device (array of 6 bytes). this is the Ethernet hardware address of your shield. Newer Arduino Ethernet Shields include a sticker with the device's MAC address. For older shields, choose your own.
ip: the IP address of the device (array of 4 bytes)
dns: the IP address of the DNS server (array of 4 bytes). optional: defaults to the device IP address with the last octet set to 1
gateway: the IP address of the network gateway (array of 4 bytes). optional: defaults to the device IP address with the last octet set to 1
subnet: the subnet mask of the network (array of 4 bytes). optional: defaults to 255.255.255.0
Returns
The DHCP version of this function, Ethernet.begin(mac), returns an int: 1 on a successful DHCP connection, 0 on failure. The other versions don't return anything.
Example
#include <SPI.h>
#include <Ethernet.h>
// the media access control (ethernet hardware) address for the shield:
byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };
//the IP address for the shield:
byte ip[] = { 10, 0, 0, 177 };
void setup()
{
Ethernet.begin(mac, ip);
}
void loop () {}
Corrections, suggestions, and new documentation should be posted to the Forum.
The text of the Arduino reference is licensed under a Creative Commons Attribution-ShareAlike 3.0 License. Code samples in the reference are released into the public domain.