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Part Number: TDA4VM-Q1
Other Parts Discussed in Thread: TDA4VM

Hello TI expert team,

We are using SGMII interface between TDA4VM and Ethernet PHY ( DP83TG720SW) and running in 1Gbps mode. we have captured SGMII eye diagrams for timing validations and it seems SGMII_TX from J7 is not matching the Electrical requirements. Please find the captured waveforms for both SGMII TX and RX waveforms. could you please help us, is there any modifications we need to do on the software to get the SGMII TX signals.



  • Chaitanya,

    It seems that the TX pre/post-emphasis is enabled.

    Here are the registers to override the pre and post-cursors:

    LN_CTRL_CDBREG[a]_DRVCTRL_C0_OVRD_PREG__DRVCTR L_CM1_OVRD_PREG (0x4000+(a*0x400)+0xcc), a=0..1

    Transmit driver pre-emphasis cursor override register.

    LN_CTRL_CDBREG[a]_DRVCTRL_C0M_OVRD_PREG__DRVC TRL_CP1_OVRD_PREG (0x4000+(a*0x400)+0xd0), a=0..1

    Transmit driver post-emphasis cursor override register.

    you could try changing the DRVCTRL_C0M_OVRD_PREG__DRVCTRL_CP1_OVRD_PREG 0x108 to see if there is any improvement in the eye diagram.
  • Hi Shreyas Rao,

    Thanks for the quick update. i have passed the your recommendations to my software team, post you with the results.