title: 2 Core with one ethernet module
body: <p>I am using raspberry pi pico with earle's pico core  <a href="https://github.com/earlephilhower/arduino-pico" rel="nofollow noreferrer">earlepicocore</a>. I am using W5500 with them and I am using this library for it <a href="https://github.com/khoih-prog/EthernetWebServer" rel="nofollow noreferrer">khoih-prog/EthernetWebServer</a> .  I hava a lot of code like 1000+ line. I am doing http get and post request and then doing some stuff with these datas.  I initialize W5500 ethernet on core 0. Here is my code ;</p>
  <pre><code>void setup()
  {
    uint16_t index = millis() % NUMBER_OF_MAC;
    Ethernet.begin(mac[index], 1000);
   }
   void loop()
   {
    Serial.println(&quot;making GET request&quot;);
    
    int statusCode = httpClient.responseStatusCode();
    
    String response = httpClient.responseBody();
   .
   .
   .
   
   }
   void setup1()
  {
   
   }
   void loop1()
   {
    Serial.println(&quot;making GET request&quot;);
    
    int statusCode = httpClient.responseStatusCode();
    
    String response = httpClient.responseBody();
   .
   .
   .
   }
  
  </code></pre>
  <p>As I said, I can only use ethernet to activate in 1 core. When I activate it in 2 cores, an error occurs.</p>
  <pre><code>uint16_t index = millis() % NUMBER_OF_MAC;
    Ethernet.begin(mac[index], 1000);
  </code></pre>
  <p>When I start the code, void loop1 can http request too but after a bit, W5500 give code -2 and -3.  Errors :</p>
  <pre><code>// Could not connect to the server
  static const int HTTP_ERROR_CONNECTION_FAILED = -1;
  // This call was made when the EthernetHttpClient class wasn't expecting it
  // to be called. Usually indicates your code is using the class
  // incorrectly
  static const int HTTP_ERROR_API = -2;
  // Spent too long waiting for a reply
  static const int HTTP_ERROR_TIMED_OUT = -3;
  // The response from the server is invalid, is it definitely an HTTP
  // server?
  static const int HTTP_ERROR_INVALID_RESPONSE = -4;
  </code></pre>
  <p>So my question is, is this error appears because I am using ethernet on core 1 without initialize it ?</p>
  <p>Thank you.</p>