DP83825EVM: DP83825IRMQR

Harsha K

Part Number: DP83825EVM

Tool/software:

Hi,

I wanted to interface DP83825IRMQR to MCU with RMII interface, so for the RMII REF Clock do I need to connect 50MHzOut/LED2 to the REF_CLOCK pin of the MCU or Need to connect directly from the Crystal Oscillator Output, in that case do I need Oscillator of 50Mhz. please help me on this with some refence designs and let me know the preferred Oscillator and crystal Part numbers for 25Mhz

Regards,

Harsha

2 months ago

0 Vivaan Jaiswal 2 months ago

TI__Expert 4150 points

Hi Harsha,

If the PHY is configured as a Master, the 25MHz crystal is used to reference the 50MHz clock output from the PHY which can be connected to the MAC. If the PHY is as a Slave, there are 2 possible configurations. Either both the MAC and PHY share the same 50MHz oscillator to both their inputs, or alternatively the PHY can run on a 50MHz clock provided by the MAC. Section 7.3.10 of the datasheet has some more information about this

I don't believe we have recommended parts for crystals. For more information on crystal selection, beyond what is mentioned in the datasheet, please refer to the following application note

For reference design, I would recommend taking a loot at the schematic files for the DP83825EVM

Best Regards,

Vivaan

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DP83825EVM: DP83825IRMQR