W5200 Ethernet for Arduino Nano
Here is the connections required to connect the WIZNET WIZ820io to the Arduino NANO.
The WIZ820io uses the W5200 chip which requires a patch to the W5100 files normally provided in the Arduino Ethernet Library. WIZNET website has the new library replacement files. There are two versions. One for arduino-0023 and prior. One for arduino-1.0 and newer. The files that need replacing are w5100.c and w5100.cpp.