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DM816x - AM389x EMAC to EMAC connection for Ethernet

Chirag Solanki
Prodigy 30 points

DM816x can support 2 GMII Ethernet Port. Same is true for AM389x.

I would like to know whether I can connect GMII MAC port of DM816x to GMII MAC port of AM389x directly with Reverse GMII configuration? If yes, could you please let me know how it can be done?

I believe that In Reverse GMII MAC configuration, TX to RX & Vs Versa. Also, configuration signals will be also connected in same manner.

  • 0
    TI__Guru**** 170625 points

    Hi Chirag,

    Yes, I think you can connect the DM816x GMII MAC port to the AM389x GMII MAC port directly. We have good description for DM6467 devices, but the flow described there should be applicable to DM816x and AM389x EMACs also. The E2E post is here:

    http://e2e.ti.com/support/dsp/c6000_multi-core_dsps/f/439/t/31757.aspx

    For your convenience I am attaching also the presentation that shows the connections: 3051.Inter-DM6467_Communications_Using_Direct_GMII_Connections_E2E.pdf

    I hope these links/materials will be useful for you.

    Best Regards,

    Pavel

  • 0 in reply to Pavel Botev
    Expert 1680 points

    Hi,

    Could any one please let me know what are changes require in driver to do MAC-to-MAC communication in DM8168?

  • 0 in reply to Rakesh Modi
    TI__Intellectual 2750 points

    Hi

    Pass phy id as empty string ("") in davinci emac platform data and select which speed you need or programming the other mac in the following code in davinci_emac.c driver

    1685         } else {
    1686                 /* No PHY , fix the link, speed and duplex settings */
    1687                 dev_notice(emac_dev, "no phy, defaulting to 100/full\n");
    1688                 priv->link = 1;
    1689                 priv->speed = SPEED_100;
    1690                 priv->duplex = DUPLEX_FULL;
    1691                 emac_update_phystatus(priv);
    1692         }

    Regards
    Mugunthan V N

  • 0 in reply to Mugunthan V N
    Expert 1680 points

    Hi Mugunthan,

    I have done above settings in kernel code to do mac-to-mac communication, but I found that if I do not connect ethernet cable to RJ-45 jack, I am not getting GMTCLK from processor.

    I am doing this experiment on daughter card of Dm8168EVM.

    Could you please let me know why the GMTCLK is not available in absence of Ethernet cable?

    Thanks

    Rakesh Modi