W5100S is an embedded Ethernet controller designed as a full hardwired TCP / IP with WIZnet technology. W5100S provides internet connectivity to your embedded system by using SPI (Serial Peripheral Interface) or Parallel System BUS.
SPI and Parallel System BUS provide easy connection via external MCU to W5100S.The clock speed of W5100S SPI supports upto 70MHz and the Parallel System Bus supports higher speed network communication than SPI.