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8147 CPRGMII Internal Delay Mode doesn't work

he liang
Prodigy 160 points

I tried the DM8147 CPRGMII Internal Delay Mode by changing GMII_SEL reg.

But the timing of signals output from rgmii interface does not change at all.

Is there something wrong?

GMII_SEL is 0x0000030a in the image below, so the rgmii is in the Internal Delay Mode.

 

GMII_SEL is 0x0000033a in the image below, so the rgmii has No Internal delay.

The pink one is RGMII0_TXD2, the blue one is RGMII0_GMTCLK, and the yellow one is RGMII0_TXEN.

There is really nothing different between the two images!

  • 0
    TI__Guru**** 170625 points

    He Liang,

    he liang said:
    The pink one is RGMII0_TXD2, the blue one is RGMII0_GMTCLK, and the yellow one is RGMII0_TXEN.

    The signal which is affected by the GMII_SEL internal delay feature is EMAC[x]_RGTXC. See DM814x datasheet (screen shot below):

    Best regards,
    Pavel

  • 0 in reply to Pavel Botev
    Prodigy 160 points

    Sorry, I mean I can't make it into normal mode.

    All of these two images are in the internal delay mode.

  • 0 in reply to he liang
    TI__Guru**** 170625 points

    He Liang,

    he liang said:

    Sorry, I mean I can't make it into normal mode.

    All of these two images are in the internal delay mode.

    From what I understand you are monitoring three signals on the scope: RGMII0_TXD2, RGMII0_GMTCLK and RGMII0_TXEN.

    While the changes between "internal delay" and "no internal delay" modes should be into the EMAC[x]_RGTXC signal.

    Regards,
    Pavel

  • 0 in reply to Pavel Botev
    TI__Guru**** 170625 points

    He Liang,

    We have several E2E community members that are using the EMAC internal delay successful, see the below e2e threads:

    http://e2e.ti.com/support/dsp/davinci_digital_media_processors/f/717/t/169742.aspx

    http://e2e.ti.com/support/dsp/davinci_digital_media_processors/f/716/t/178450.aspx

    http://e2e.ti.com/support/dsp/davinci_digital_media_processors/f/716/t/252657.aspx

    http://e2e.ti.com/support/dsp/davinci_digital_media_processors/f/716/t/155890.aspx

    http://e2e.ti.com/support/dsp/davinci_digital_media_processors/f/716/t/170318.aspx

    Best regards,
    Pavel