Ethernet Webserver together with UDP

Projects Networking, Protocols, and Devices
1

Hello,

I got a Problem when using the Webserver example together with an UDP Listener.
If i start the Webserver alone everything is fine.
Same happens when the UDP Listener is called alone.
But together i am only able to get the Webserver working when stripping it down. That means i can only have one IF case for the input buttons (as seen in the webserver example).

client.println("HTTP/1.1 200 OK");
          client.println("Content-Type: text/html");
          client.println();
          client.println("<div align=center>");
          client.print("<body style=background-color:lightblue>");
          client.println("<font color=red><h1>HTML Testsite</font></h1>");
          client.println("<hr/>");
          client.println("<h1><font color='#2076CD'>Room</font color></h1>");
          client.println("<hr />
");
          client.println("<form method=GET>");
	  if (lon == true) {
            client.println("<input type=submit value=light  name=1 style=width:200;height:100;background-color:red;/>");
          }else {
            client.println("<input type=submit  value=light name=0 style=width:200;height:100;background-color:lightgreen;>");
          }
// --->>  If this is left out everything works, even with UDP called !
//          if (mon == true) {
//            client.println("<input type=submit name=1 value=motor style=width:200;height:100;background-color:red>");
//          }else{
//            client.println("<input type=submit name=0 value=motor style=width:200;height:100;background-color:lightgreen>");
//          }
//
          client.println("</form></body></html>");
          break;

If i do a second IF case for a second input type button, the arduino resets every second.

The UDP code is:

void udptest(){
  int packetSize = Udp.available(); 
  if(packetSize){
    packetSize = packetSize - 8;      // subtract the 8 byte header
    Udp.readPacket(packetBuffer,1024, remoteIp, remotePort);
    Serial.println(MAX_BUFFER_UDP);      
    for (int i=0;i<7;i++){         
      Serial.println(packetBuffer[i]);
    }
  }
}

And it is called in the main loop as

void loop()  {  
  webserv();   
//  delay(1000);
  udptest();
//    delay(1000);
}

I have the DFRduino Ethernet shield attached to a Nano 3.0.

I am out of ideas, can anyone help me ?

greets

2

You have an awful lot of strings, in just that little snippet. I'm guessing that you are running out of memory. The Nano 3.0 has only 2K of SRAM.

3

tdrat:
But together i am only able to get the Webserver working when stripping it down. That means i can only have one IF case for the input buttons (as seen in the webserver example).

Sounds like you're running out of RAM.

I think you need to read this page: http://www.arduino.cc/en/Reference/PROGMEM

4

Thanks for your answers, that helped me a little bit !

As the normal webserver example works very well, and there are a lot more Strings in it, I tested this with the freeMemory function.
When calling the webserver alone (with a few more lines of Strings added), I have 1028 bytes free.

And when calling the UDP function alone i only get 93 bytes of free Memory.

edit: Tested this with buffer sizes from 1 to 1024, always the same result.

So, can anyone point out why the UDP function is taking up the whole Memory ?

Thanks

5

As you found out correctly, i was eating up all sram.
Stupid me.. I did the UDP.read with a small buffer but reserved for the packetbuffer char a lot of space :slight_smile:

Thanks again,
greets