Verdin iMX8M Plus PHY to PHY

Technical Support
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1

Good Afternoon,

I am beginning the design of a carrier board for the Verdin iMX8M Plus.

I am required to connect a USB to Ethernet Bridge (ASIX AX88772C) to the Verdin iMX8M Plus’ ethernet, which would be a PHY to PHY connection on the board.

Assuming this would even work, are there any examples of something similar being done?

Thanks! Kind Regards,
Tom

2

We did something similar, and it took a long time to figure out. Our use was an RGMII connection to another device similar to an ethernet switch.

We make our own build with YOCTO, and make a custom device tree based off the default verdin one.
We modified the device tree similar to the following:

&fec {
/delete-property/ phy-handle;
status = “okay”;

    fixed-link {
            speed = <1000>;
            full-duplex;
            pause;
    };
    mdio {
            #address-cells = <1>;
            #size-cells = <0>;

            /delete-node/  ethernet-phy@7;
    };

};

3

Hello forstnert,

can you be a bit more specific? do you want to connect PHY to PHY and the PHY to USB is on a diffrent boar?
Do you have a little diagram?

Best Regards,

Matthias

4

Thanks for your replies. Hopefully the attached diagram makes my query a little clearer! It is a bit of an awkward configuration. Unfortunately I cannot use the RMII as the RMII pin’s primary function is required.

block diagram

5

Hello forstnert,

why not connect the customer Device to USB directly?

Best Regards,

Matthias

6

Hi matthias,

That would certainly be much easier! For some reason the powers that be are insistent that the above configuration is what they want.