RTC MAC Address?

[DrMag]

I'm working on a project where I'm going to be using (for the first time) a real time clock. In researching various options, one of the devices that makes sense is the MCP7941x.

This device comes in three variants: the MCP79410 has a blank EEPROM, the MCP79411 has a preprogrammed EUI-48 MAC address, and the MCP79412 has an EUI-64 MAC address.

Perhaps my understanding of the MAC address concept is too limited--why would an RTC have any need of such a thing, as there's no networking capability on the chip? (It's a simple I2C connection, and they all have the same, non-configurable I2C address anyway.) Would I really have any reason to work with either the x11 or x12 devices as opposed to just the x10?

I've been sifting through the datasheet, but it seems to not mention the included MAC address at all aside from the fact that it can be included.

[MosherIV]

Many ethernet phy/devices require non volatile memory to hold settings, so having some storage combined with rtc makes system costs lower.

Some hobbiests want to be able to integrate their own ethernet interfaces but cannot afford the registration costs required to get a MAC address, so being able to buy a device with a pre programmed MAC address is quite clever.