Hi, i have uploaded an example sketch to our github https://github.com/Industruino/democode/blob/master/MACfromRTC/MACfromRTC.ino
The RTC has a unique 8-byte identifier (EUI-64); this sketch reads last 6-bytes as a unique MAC address, dropping the first 2 bytes, part of the 3-byte OUI.
For more information you can check the RTC MCP79402 datasheet http://ww1.microchip.com/downloads/en/DeviceDoc/20005009F.pdf
Please try to give a substantial answer. If you wanted to comment on the question or answer, just use the commenting tool. Please remember that you can always revise your answers - no need to answer the same question twice. Also, please don't forget to vote - it really helps to select the best questions and answers!