Phy Input Clock DP83848C PHYTER

[Altera_Forum]

Hi , 

 I am using Altera CYCLONE III ,I have implemented NIOS II + Onchip memory + SSRAM + Custom MAC (RMII Mode).I want to configure the PHY to RMII Mode.For that I think I have to connect 50 MHz Clock to X1 pin of the DP83848C PHYTER . How to make this connection ?

[Altera_Forum]

Did you have a look at the schematic? Where is that pin connected?

[Altera_Forum]

Hi , 

 I looked at the schematic.The X1 Pin is connected to a crystal oscillator . I am attaching the schematic here.Refer Page 3. I want to know whether we have options to configure the Crystal oscillator to generate a 50MHz clock or externally we have to connect 50MHz clock.If So I don't know how to make the things happen ?   I am attaching the PHY Document also . There is one particular register in PHY to configure in RMII Mode [Register No 0x17,]If I configure it to RMII Mode , whether 50 MHz clock will be generated ? If this happens No need to configure the crystal oscillator for 50 MHz / external clock connection .

[Altera_Forum]

It looks like you can't change the oscillator frequency on that board, wich measn that you can't use the phy in RMII mode. 

A solution may be to convert the signals from RMII to MII inside the FPGA between the custom MAC and the Phy, or to modify the Mac so that it can run in RMII mode.

[Altera_Forum]

hi , 

Thanks a lot .After your suggestion i came to a conclusion that my Board wont support RMII Mode.I will Start working with RMII to MII Convertor.