My MAC and PHY (separate chips, because the MAC is onboard on the MCU) are both capable of talking either MII or RMII, and I'm trying to evaluate the trade-offs. This is for a single-port device. Looks like RMII uses fewer PCB traces and requires a 50MHz oscillator, while MII uses a few more traces and a 25MHz crystal plus 2 capacitors. RMII seems to win on board space and design effort. MII would seem to win on component cost (an oscillator is about US$1 more than a crystal+caps) and EMI issues, due to the lower signalling rate, which would make the whole thing more reliable.
Anything I'm missing? If you've been faced with this decision before, what was your choice?
TIA,