embedded 原文存档
arduino 使用w5500模块（USR-ES1）进行有线连接网口RJ45
一，硬件：
- USR-ES1模块这个淘宝上卖的比较火，所以我们用的这个。
- 板子用mega2560，理论上可以用在任何arduino上，包括stm32，esp系列
二，软件：
- VSCODE+PlatformIO+arduino框架
- 使用的Ethernet3.0，地址：https://github.com/sstaub/Ethernet3
三，接口：
1，RST是硬件复位引脚，一定要接线
2，我一共连了7根线，RST(5)，CS(4)，SCK(52)，MISO(50)，MOSI(51)，3.3V，GND。
| Arduino / Genuino Board | MOSI | MISO | SCK | CS (slave) | CS (master) | Level |
| Uno or Duemilanove | 11 or ICSP-4 | 12 or ICSP-1 | 13 or ICSP-3 | 10 | - | 5V |
| Mega1280 or Mega2560 | 51 or ICSP-4 | 50 or ICSP-1 | 52 or ICSP-3 | 53 | - | 5V |
| Leonardo | ICSP-4 | ICSP-1 | ICSP-3 | - | - | 5V |
| Due | SPI-4 | SPI-1 | SPI-3 | - | 4, 10, 52 | 3,3V |
| Zero | ICSP-4 | ICSP-1 | ICSP-3 | - | - | 3,3V |
| 101 | 11 or ICSP-4 | 12 or ICSP-1 | 13 or ICSP-3 | 10 | 10 | 3,3V |
| MKR1000 | 8 | 10 | 9 | - | - | 3,3V |
（上表是arduino的SPI引脚的官网引脚表，CS我们可以自己设置）
可以使用下面2句函数设置CS引脚和RST引脚
`//这里Ethernet不改变，且放在实例如client.begin()前面 Ethernet.setCsPin(4); Ethernet.setRstPin(5);`四，程序
`#include <SPI.h> #include <Ethernet3.h> // Enter a MAC address for your controller below. // Newer Ethernet shields have a MAC address printed on a sticker on the shield byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED }; // if you don't want to use DNS (and reduce your sketch size) // use the numeric IP instead of the name for the server: //IPAddress server(74,125,232,128); // numeric IP for Google (no DNS) char server[] = "www.baidu.com"; // name address for Google (using DNS) // Set the static IP address to use if the DHCP fails to assign IPAddress ip(192, 168, 0, 177); // 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): EthernetClient client; void setup() { // Open serial communications and wait for port to open: Serial.begin(9600); while (!Serial) { ; // wait for serial port to connect. Needed for Leonardo only } Ethernet.setCsPin(4); Ethernet.setRstPin(5); // start the Ethernet connection: if (Ethernet.begin(mac) == 0) { Serial.println("Failed to configure Ethernet using DHCP"); // no point in carrying on, so do nothing forevermore: // try to congifure using IP address instead of DHCP: Ethernet.begin(mac, ip); } // 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(server, 80)) { Serial.println("connected"); // Make a HTTP request: client.println("GET /search?q=arduino HTTP/1.1"); client.println("Host: www.baidu.com"); client.println("Connection: close"); client.println(); } else { // kf 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: while (true); } }`五，串口收到的数据如下
`connected HTTP/1.1 301 Moved Permanently Cache-Control: max-age=86400 Content-Length: 246 Content-Type: text/html; charset=iso-8859-1 Date: Thu, 16 Dec 2021 01:26:03 GMT Expires: Fri, 17 Dec 2021 01:26:03 GMT Location: http://www.baidu.com/search/?q=arduino Server: Apache Connection: close <!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN"> <html><head> <title>301 Moved Permanently</title> </head><body> <h1>Moved Permanently</h1> <p>The document has moved <a href="http://www.baidu.com/search/?q=arduino">here</a>.</p> </body></html> disconnecting.`