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[Reply #30 on:]

I think you should have success if you keep exploring the option to avoid the "while (readSnCR(s));" statement.

I found the RTR and RCR registers in the wiznet w5100 datasheet.  You can download a copy from here (sparkfun) or from the wiznet website.

[Reply #31 on:]

SOLVED!

In the w5100.h there are two methods:

Code:

void W5100Class::setRetransmissionTime(uint16_t _timeout) {
  writeRTR(_timeout);
}

void W5100Class::setRetransmissionCount(uint8_t _retry) {
  writeRCR(_retry);
}

They are not used anywhere in the Ethernet library, so these get some default values. If you want to change these settings, just modify the begin() function in Ethernet.cpp to:

Code:

void EthernetClass::begin(uint8_t *mac, uint8_t *ip, uint8_t *gateway, uint8_t *subnet)
{
  W5100.init();
  W5100.setMACAddress(mac);
  W5100.setIPAddress(ip);
  W5100.setGatewayIp(gateway);
  W5100.setSubnetMask(subnet);
 // Add the following two lines:
  W5100.setRetransmissionTime(50); // in milliseconds, 50 is a good value
  W5100.setRetransmissionCount(1); // tries just once
}

Now my Arduino freezes just for 50 millis every 12 seconds, which is acceptable.

Thank you, dhunt for pointing me in the right direction!

[Reply #32 on:]

It would be nice to see this added to the official version of the library, with default arguments for the begin method, so that a user could override the default values if desired.