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13 years agoFor anyone interested in the Answer, the lower 2 config strap bits on the phy are what set the PHY Address. The Marvell PHY has a pretty elaborate boot strap configuration. When it comes out of reset it takes 3 samples on each config pin. If the pin is tied to ground, all three samples are 0. If the config pin is tied to VDD, all three bits are 1. If the config pin is tied to several available LED output pins, the 3 bits will be dependent on which LED it is connected to. Each of the available LED pins (multi use) generate a different 3 bit pattern at boot up then move into their normal link LED \ status LED function.
If you need more info on this you will need the Marvell PHY spec sheet. Its pretty confusing stuff but basically if your lower two config pins are grounded, you PHY ADDR is going to be 0. I think Altera should have used something other than the broadcast address. But since there is only 1 PHY device on the board its not really a problem.