How to properly reset Ethernet connection

Using Arduino Networking, Protocols, and Devices
#1

I am building a datalogger that will POST data to a website and I would like to design it to run for years.

The way I have it set up is that it resets the W5200 when it fires up. Then resets the connection with this (resetPin is the reset of the the W5200 module):

void resetCon() {
  wdt_reset();
  digitalWrite(resetPin, LOW);
  delay(2000);
  digitalWrite(resetPin, HIGH);
  delay(1000);
  wdt_reset();
  #if defined(WIZ550io_WITH_MACADDRESS)
  if (Ethernet.begin() == 0) {
#else
  if (Ethernet.begin(mac) == 0) {
#endif  
    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:
  
  wdt_reset();
  
#if defined(WIZ550io_WITH_MACADDRESS)
    Ethernet.begin(ip);
#else
    Ethernet.begin(mac, ip);
#endif  
  }

This works fine at first. The problem comes when a connection is not made, I call resetCon() again just to make sure that this is not the issue. When I do this, my RAM drops by over 100 each time.

How can I reset the connection without eating up my RAM?

Thanks!

#2

When I do this, my RAM drops by over 100 each time.

Because Ethernet.begin() is failing to free something?

#3

PaulS is right. It obviously isn't freeing or reusing the memory.

However, that is not an Arduino (Arduino.cc) library, so I can't offer much help. Maybe a link to the hardware and library you are using might help.

If your sketch client code is written correctly, you shouldn't need to reset the w5200.

#4

I am using the library and WebClient sketch that came with the Arduino IDE v1.0.5 as the base. I found a link to the sketch here gr_ethernet_examples/gr_WebClient.cpp at master · embeddist/gr_ethernet_examples · GitHub

I wrote the resetCon() function to incorporate parts of the sketch. That is not part of any library.

My goal for this sketch is to test Arduino as a remote datalogger that could potentially be installed in thousands of locations and operate for years without human interaction. So if something goes wrong, I want the unit to completely reset itself.

The reason I have the reset in the connection is to act as a 'catch all'. If it loses connection for any reason, it will just reset. That way, even if some strange condition arises, it will eventually correct itself.

For now, I just have it set to monitor the free memory, and if it drops below 250, it times out the watchdog and does a full system reset. Not the most elegant, but at least it should work.

Are you saying that I can drop the reset and it should still function the same?

#5