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User1580871742356367's avatar
User1580871742356367
Icon for Occasional Contributor rankOccasional Contributor
4 years ago

DDR4 controller DQS pins

I wonder if the polarity of DQS signal can be inverted inside FPGA (not HPS), for example, bank 3F or 3H.

The DQS_P and DQS_N connection are reversed at one DDR4 device side and there 4 DDR4 devices forming a 64 bit memory bank.

Hope to hear from ASAP. Thank you.

4 Replies

  • AdzimZM_Altera's avatar
    AdzimZM_Altera
    Icon for Regular Contributor rankRegular Contributor

    Hi Sir,


    Thanks for posting your question in Intel Community.


    Unfortunately, you cannot change the polarity of the DQS signal.


    Regards,

    Adzim


  • User1580871742356367's avatar
    User1580871742356367
    Icon for Occasional Contributor rankOccasional Contributor

    Hi Adzim,

    Appreciate quick response.

    I know the DQS P/N pins can not be changed or swapped.

    I meant inverting DQS in the VHDL or Verilog code, for example, somewhere in the MIG, like put a NOT gate.

    ASAP, thank you.

    • AdzimZM_Altera's avatar
      AdzimZM_Altera
      Icon for Regular Contributor rankRegular Contributor

      Hi Sir,

      I don't think you can do that due to timing related issue.

      Besides, the signals are harden circuitry that you not able to change it.

      Regards,

      Adzim

  • sstrell's avatar
    sstrell
    Icon for Super Contributor rankSuper Contributor

    I'm presuming you're using a hard controller and PHY. If so, no, you can't do that. You wouldn't want to either due to extra delay.