To the average microcontroller, Ethernet networks are quite a step up from the basic I2C, SPI and UART interfaces ... This is what the SatCat5 FPGA-based project by [The Aerospace Corporation ...

CoreI2C provides an APB-driven serial interface, supporting I2C, SMBus, and PMBus data transfers. Several Verilog/VHDL parameters are available to minimize FPGA fabric area for a given application.

Features a simple command interface and permits multiple I2C slaves to be controlled directly from your FPGA, CPLD or ASIC device. Supports standard (100 kbits/s), fast (400 kbits/s) and custom data ...