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TUSB1142: Read back AEQ gain on pin-strap mode

Alder Lim
Prodigy 190 points
Part Number: TUSB1142

Tool/software:

Hello TI guru,

We design TUSB1142 into our Devkit and getting issue on supporting long wire.

We used TUSB1142 as pin-strap mode and set full AEQ enable with FULLAEQ_UPPER_EQ = Fh.

Suppose it should sweep from low to 15, full range, right ?

Does it have any way to read back the gain value for Full AEQ after the sweeping, in pin-strap mode?

Thanks,
Best regards,
Alder

  • 0
    TI__Guru**** 176671 points

    Alder

    The Full AEQ mode attempts to find what it believes is the best equalization value for CRX1 and CRX2 receivers by starting at the lowest EQ value and sweeping through all EQ combinations up to the FULLAEQ_UPPER_EQ limit. The FULLAEQ_UPPER_EQ limit is set by the AEQCFG pin in pin-strap mode. But there is no way to read back the tuned AEQ value in the pin-strap mode.

    Thanks
    David

  • 0
    Prodigy 190 points

    Hello David,

    Currently I set  FULLAEQ_UPPER_EQ = Fh. It is full EQ (#15 = 12.7dB, EQCFG=1), right ?

    By the ways, i would like to perform simulation to get the correct gain value for my design, can help to share spice/ibis simulation file?

    Does TUSB1142 has pre/de-emphasis ?

    Thanks,
    Best regards,
    Alder

  • 0 in reply to Alder Lim
    TI__Guru**** 176671 points

    Alder

    Currently I set  FULLAEQ_UPPER_EQ = Fh. It is full EQ (#15 = 12.7dB, EQCFG=1), right ?

    Correct

    By the ways, i would like to perform simulation to get the correct gain value for my design, can help to share spice/ibis simulation file?

    Currently we do not have IBIS-AMI model available for TUSB1142. But you can use the attached spreadsheet to estimate the insertion loss. The spreadsheet will also provide a recommended EQ setting. The password for the spreadsheet is 'ti'.

    RX & TX trace length budgeting - TI information - selective disclosure - revI.xlsx

    Does TUSB1142 has pre/de-emphasis ?

    Limited mode is supported on SSTX only. When in limited mode, TUSB1142 provides both pre-shoot and de-emphasis.

    Thanks

    David

  • 0 in reply to David (ASIC) Liu
    Prodigy 190 points

    Thank you David