Article ID: 000080681 Content Type: Troubleshooting Last Reviewed: 10/23/2019

Why does the Intel® Stratix® 10 25G Ethernet IP core receive random erroneous packets in open ended condition?


  • Intel® Quartus® Prime Pro Edition
  • 25G Ethernet Intel® FPGA IP

    In rare cases, the Intel® Stratix® 10 25G Ethernet IP core may still receive random erroneous packets when operating in open ended condition, i.e. there is no fiber or QSFP28 module connected.



    A workaround for this problem is to edit the SYNOPT_STRICT_SOP parameter in the top level IP wrapper file to 1.

    This workaround is only available for designs with Preamble Pass-Through feature disabled.


    Locate the 25G Ethernet IP variant wrapper file at /synth/<file_name>.v.

    At the instantiation of the version specific 25G Ethernet IP, change the SYNOPT_STRICT_SOP parameter setting from (0) to (1).

    Do not regenerate the 25G Ethernet IP core. Compile your design.


    Example design IP variant file at /synth/ex_25g.v:

    ex_25g_alt_e25s10_191_dyjat6a #(

        .SYNOPT_READY_LATENCY          (0),

        .SYNOPT_CORE_VAR                      (0),

        .SYNOPT_KHZ_REF_EN                  (0),

        .SYNOPT_RSFEC                              (0),

        .SYNOPT_DIV40                               (1),

        .SYNOPT_LINK_FAULT                    (0),

        .SYNOPT_STRICT_SOP                  (1),

        .SYNOPT_PREAMBLE_PASS          (0),


    Please note that you may observe junk data on the 64-bit l1_rx_data bus. The l1_rx_valid should be used as an indicator to accept or ignore the data.


    This problem is scheduled to be fixed in a future release of the Intel® Quartus® Prime Pro Edition software.

    Related Products

    This article applies to 1 products

    Intel® Stratix® 10 FPGAs and SoC FPGAs



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