Content originally posted in LPCWare by MikeSimmonds on Sat Jan 09 22:15:22 MST 2016
'0R' is zero (0) ohms. Just a wire link.
Use a 25 MHz crystal for RMII mode
or a 50 Mhz crystal for MII mode (not recommended).
YOU can Google for data sheets and application notes.
Cheers, Mike.