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Thread: Ethernet (TCP) problems with Teensy 4.1

  1. #1
    Junior Member
    Join Date
    Jan 2021
    Posts
    9

    Ethernet (TCP) problems with Teensy 4.1

    Hey guys!

    I have some problems with my Teensy 4.1...

    I use Teensyduino 1.53, Arduino 1.8.13, Teensy 4.1, the latest Putty version, the latest verisons of NativEthernet and Fnet.

    I tried to use it as a telnet server (). But there was the problem that I did not got the clients IP back.

    So I tried to fix it but didn't find an answer. I also tried to run the example sketch for the chat server.

    Code:
    /*
     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.
    
     Circuit:
     * Ethernet shield attached to pins 10, 11, 12, 13
    
     created 18 Dec 2009
     by David A. Mellis
     modified 9 Apr 2012
     by Tom Igoe
    
     */
    
    #include <SPI.h>
    #include <NativeEthernet.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[] = {
      0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };
    IPAddress ip(169, 254, 239, 179);
    //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 alreadyConnected = false; // whether or not the client was connected previously
    
    void setup() {
      // You can use Ethernet.init(pin) to configure the CS pin
      //Ethernet.init(10);  // Most Arduino shields
      //Ethernet.init(5);   // MKR ETH shield
      //Ethernet.init(0);   // Teensy 2.0
      //Ethernet.init(20);  // Teensy++ 2.0
      //Ethernet.init(15);  // ESP8266 with Adafruit Featherwing Ethernet
      //Ethernet.init(33);  // ESP32 with Adafruit Featherwing Ethernet
    
      // initialize the ethernet device
      Ethernet.begin(mac, ip, subnet);
    
      // Open serial communications and wait for port to open:
      Serial.begin(9600);
       while (!Serial) {
        ; // wait for serial port to connect. Needed for native USB port only
      }
    
      // Check for Ethernet hardware present
      if (Ethernet.hardwareStatus() == EthernetNoHardware) {
        Serial.println("Ethernet shield was not found.  Sorry, can't run without hardware. :(");
        while (true) {
          delay(1); // do nothing, no point running without Ethernet hardware
        }
      }
      if (Ethernet.linkStatus() == LinkOFF) {
        Serial.println("Ethernet cable is not connected.");
      }
    
      // start listening for clients
      server.begin();
    
      Serial.print("Chat server address:");
      Serial.println(Ethernet.localIP());
    }
    
    void loop() {
      // wait for a new client:
      EthernetClient client = server.available();
    
      // when the client sends the first byte, say hello:
      if (client) {
        if (!alreadyConnected) {
          // clear out the input buffer:
          client.flush();
          Serial.println("We have a new client");
          client.println("Hello, client!");
          alreadyConnected = true;
        }
    
        if (client.available() > 0) {
          // 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.write(thisChar);
        }
      }
    }
    Short: it doesn't work.

    Ping is working.
    Then I tried to analyse the communication between my laptop and the Teensy 4.1. I compared it to the Arduino Uno. The difference is/was that TCP works great with the Arduino, but somehow it doesn't want to work with the Teensy. Here is a small cutout out of wireshark : I tried to get the connection with PuTTy. And this is the result

    Click image for larger version. 

Name:	PuTTy connection.jpg 
Views:	12 
Size:	80.9 KB 
ID:	23396

    After this wasn't working, I tried to figure out where the problem is.

    So I decided to try if the WebServer example works, because I use port 80 here and HTTP.

    Code:
    /*
      Web Server
    
     A simple web server that shows the value of the analog input pins.
     using an Arduino Wiznet Ethernet shield.
    
     Circuit:
     * Ethernet shield attached to pins 10, 11, 12, 13
     * Analog inputs attached to pins A0 through A5 (optional)
    
     created 18 Dec 2009
     by David A. Mellis
     modified 9 Apr 2012
     by Tom Igoe
     modified 02 Sept 2015
     by Arturo Guadalupi
     
     */
    
    #include <SPI.h>
    #include <NativeEthernet.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
    };
    IPAddress ip(169,254, 239, 188);
    
    // Initialize the Ethernet server library
    // with the IP address and port you want to use
    // (port 80 is default for HTTP):
    EthernetServer server(80);
    
    void setup() {
      // You can use Ethernet.init(pin) to configure the CS pin
      //Ethernet.init(10);  // Most Arduino shields
      //Ethernet.init(5);   // MKR ETH shield
      //Ethernet.init(0);   // Teensy 2.0
      //Ethernet.init(20);  // Teensy++ 2.0
      //Ethernet.init(15);  // ESP8266 with Adafruit Featherwing Ethernet
      //Ethernet.init(33);  // ESP32 with Adafruit Featherwing Ethernet
    
      // Open serial communications and wait for port to open:
      Serial.begin(115200);
      while (!Serial) {
        ; // wait for serial port to connect. Needed for native USB port only
      }
      Serial.println("Ethernet WebServer Example");
    
      pinMode(A1, OUTPUT);
      digitalWrite(A1, HIGH);
    
      // start the Ethernet connection and the server:
      Ethernet.begin(mac, ip);
    
      // Check for Ethernet hardware present
      if (Ethernet.hardwareStatus() == EthernetNoHardware) {
        Serial.println("Ethernet shield was not found.  Sorry, can't run without hardware. :(");
        while (true) {
          delay(1); // do nothing, no point running without Ethernet hardware
        }
      }
      if (Ethernet.linkStatus() == LinkOFF) {
        Serial.println("Ethernet cable is not connected.");
      }
    
      // start the server
      server.begin();
      Serial.print("server is at ");
      Serial.println(Ethernet.localIP());
    }
    
    
    void loop() {
      // listen for incoming clients
      EthernetClient client = server.available();
      if (client) {
        Serial.println("new client");
        // an http request ends with a blank line
        boolean currentLineIsBlank = true;
        while (client.connected()) {
          if (client.available()) {
            char c = client.read();
            Serial.write(c);
            // if you've gotten to the end of the line (received a newline
            // character) and the line is blank, the http request has ended,
            // so you can send a reply
            if (c == '\n' && currentLineIsBlank) {
              // send a standard http response header
              client.println("HTTP/1.1 200 OK");
              client.println("Content-Type: text/html");
              client.println("Connection: close");  // the connection will be closed after completion of the response
              client.println("Refresh: 5");  // refresh the page automatically every 5 sec
              client.println();
              client.println("<!DOCTYPE HTML>");
              client.println("<html>");
              // output the value of each analog input pin
              for (int analogChannel = 0; analogChannel < 6; analogChannel++) {
                int sensorReading = analogRead(analogChannel);
                client.print("analog input ");
                client.print(analogChannel);
                client.print(" is ");
                client.print(sensorReading);
                client.println("<br />");
              }
              client.println("</html>");
              break;
            }
            if (c == '\n') {
              // you're starting a new line
              currentLineIsBlank = true;
            } else if (c != '\r') {
              // you've gotten a character on the current line
              currentLineIsBlank = false;
            }
          }
        }
        // give the web browser time to receive the data
        delay(1);
        // close the connection:
        client.stop();
        Serial.println("client disconnected");
      }
    }
    This worked well.


    Here another picture of the analysis of ping:

    Click image for larger version. 

Name:	Ping.jpg 
Views:	8 
Size:	40.7 KB 
ID:	23397




    The configuration of my ethernet part of the PCB:

    Click image for larger version. 

Name:	PCB Ethernet.jpg 
Views:	8 
Size:	143.7 KB 
ID:	23398



    Could anybody help me out? I appreciate every hint!
    Could there be a bug in the NativeEthernet library? Or is there anyone where this sketch or anything with TCP works?

    Thank you!

    Regards

    MichaelS
    Last edited by MichaelS; 01-21-2021 at 01:24 PM.

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