Arduino_Ethernet(2)

簡單記錄一下Ethernet library該注意的事項:

1. Ethernet library主要有5個class
   |- Ethernet Class -> 主要是用來初始化設定
   |- IPAddress Class -> 即IP Address的class
   |- Server Class -> 用來建立Server使用
   |- Client Class -> 用來建立Client使用
   |- EthernetUDP class -> 收發UDP的message

2. Ethernet Class:
依照官網的敘述:
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.
如果區網中有配置DHCP，直接使用Ethernet.begin(mac)即完成初始化的動作，Ethernet shield會自動獲得IP address

Ethernet Class包含的method:
|- begin() -> 初始化Ethernet object
|- localIP() -> return the local IP
|- maintain()

3. IPAddress Class:
依照官網的敘述:
Defines an IP address. It can be used to declare both local and remote addresses.
所以IPAddress Class是用來定義IP address

註:官網中描述的使用方法:
IPAddress ip(192,168,1,1);
Ethernet.begin(mac, ip, gateway, subnet);

4. 自動取得IP Address的Sample Code:

#include 
#include 

byte mac[] = {0xDE,0xAD,0xBE,0xEF,0xFE,0xED};
byte server[] = {173,194,72,138};
EthernetClient client;

void setup(){
  Serial.begin(9600);
  if(Ethernet.begin(mac)==0){
    Serial.println("Failed to configure Ethernet usin DHCP!");
    while(1);
  }
  delay(1000);
  Serial.print("IP Address: ");
  
  //Ethernet.localIP() -> Obtains the IP address of the Ethernet shield.
  //Useful when addres is auto assigned through DHCP
  IPAddress myIPAddress = Ethernet.localIP();
  Serial.print(myIPAddress);
  if(client.connect(server,80)){
    Serial.println("connected...");
    client.println("GET /search?q=arduino HTTP/1.0");
    client.println();
  }
  else{
    Serial.println("connection failed!");
  }
}

void loop(){
  if(client.available()){
    char c = client.read();
    Serial.print(c);
  }
  if(!client.connected()){
    Serial.println();
    Serial.println("disconnecting");
    while(1);
  }
}

run的結果: