Article ID: 000083526 Content Type: Troubleshooting Last Reviewed: 02/15/2012

Extra Preamble on GMII Receive Interface Due to PPM Frequency Difference

Environment

  • Quartus® II Subscription Edition
  • Ethernet
    • BUILT IN - ARTICLE INTRO SECOND COMPONENT

    Critical Issue

    Description

    When the parts per million (PPM) frequency difference between the PCS receive clock and the external PHY transmit clock is not zero, the GMII receive interface will receive and extra preamble (0x55) on the gmii_rx_d data bus.

    This issue affects all designs that contain GXB transceiver block.

    Resolution

    This issue has no workaround.This issue is fixed in version 11.1 SP1 of the Triple-Speed Ethernet MegaCore function.

    Related Products

    This article applies to 1 products

    Intel® Programmable Devices

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