DP83848M: Schematic Functionality

Mark Philip Felipe

Part Number: DP83848M

Hi Team, seeking your assistance from a customer. Attached is the schematic.

The main concerns are.

If the clock reference is correct with the RMII mode.

Do I need to use 25MHz or 50MHz in X1/X0 pin using RMII mode?

Should I connect a 50MHz reference signal between the PHY and the micro? If yes, which on PHY's pin should be used?

Thank you.

-Mark

Sheet1 (1).pdf

over 4 years ago

0 Adrian Kam over 4 years ago

TI__Expert 5425 points

Hi Mark,

Since you are using RMII mode, XI pin should be connected to a 50 MHz oscillator. XO pin is left floating because an oscillator is being used.
Yes, you should connect the 50MHz reference clock to both the PHY and the MAC, as there is no pin on the PHY that can be used.

Below is a link to an app note for your reference:

https://www.ti.com/lit/an/snla076a/snla076a.pdf?ts=1618011001820

Regards,

Adrian Kam

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DP83848M: Schematic Functionality