If there is ambition to work at high speeds and feeds I would jump straight to FPGA and bypass anything like this WIZnet ASIC which simultaneously does too much and too little to be relevant to that pursuit (but it is great if you have the exact use case of wanting to add Ethernet to an existing MCU).
Doing Ethernet at the logic design level is a lot of hard work but it isn't exactly a mystery at this point unless you are working on next generation speeds and feeds. A book on digital design, a book on HDL of choice, and a willingness to read specifications (IEEE 802, SFP MSA) and datasheets (FPGA MAC, third party PHY chips) is what you need to be successful.
NetFPGA collates a lot of teaching materials and example code for this but the major FPGA vendors also have relevant works. Ignore any suggestions that you need formal education in the space, it's simply not true.
Doing Ethernet at the logic design level is a lot of hard work but it isn't exactly a mystery at this point unless you are working on next generation speeds and feeds. A book on digital design, a book on HDL of choice, and a willingness to read specifications (IEEE 802, SFP MSA) and datasheets (FPGA MAC, third party PHY chips) is what you need to be successful.
NetFPGA collates a lot of teaching materials and example code for this but the major FPGA vendors also have relevant works. Ignore any suggestions that you need formal education in the space, it's simply not true.