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HPS RGMII EMAC connection to external MAC inference

Added by S. D. about 1 year ago

I've been able to get a successful connection b/w the HPS RGMII EMAC with an external PHY, but my design also uses a mitySOM that connects to a KSZ9897R's MAC interface port (so an HPS RGMII EMAC connection to an external MAC interface). When testing this mac-to-mac connection I seem to be able to transmit from the MitySOM TX lines, but I cannot receive anything on the RX lines. Could this have anything to do with the MitySOM or Cyclone V not supporting an external MAC interface? When reviewing Intel's Cyclone V documentation I only find advice on the HPS EMAC connection to external PHY interfaces.


Replies (5)

RE: HPS RGMII EMAC connection to external MAC inference - Added by Michael Williamson about 1 year ago

Hello,

Can you send a sample schematic / snippet of your design around the KSZ9897 in question? We can provide a provide email or NDA if required.

With regards,
Mike

RE: HPS RGMII EMAC connection to external MAC inference - Added by S. D. about 1 year ago

Definitely -- just an email would do.

RE: HPS RGMII EMAC connection to external MAC inference - Added by S. D. about 1 year ago

UPDATE:

Adding 22Ω series termination resistors on the RX RGMII traces leading into the mitySOM module solved this issue! Ethernet works great now.

RE: HPS RGMII EMAC connection to external MAC inference - Added by Thomas Catalino about 1 year ago

Thank you for the update, it was great to meet you today!

Tom

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