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  3. AR# 50328: LogiCORE IP Ethernet 1000BASE-X PCS/PMA or SGMII v11.3 - Update to reset logic for 7 Series SGMII with Elastic Buffer

AR# 50328

LogiCORE IP Ethernet 1000BASE-X PCS/PMA or SGMII v11.3 - Update to reset logic for 7 Series SGMII with Elastic Buffer

Description

If targeting 7 series with the Ethernet 1000BASE-X PCS/PMA or SGMII core generated for Tri-Speed SGMII with the Fabric Elastic Buffer, an update is needed to the reset logic. This update is only needed for SGMII with the fabric Elastic buffer and does not affect 1000BASE-X or SGMII generated without the fabric Elastic buffer. The reason for this is if the rx elastic buffer gives out a buffer error, it is routed back as reset to the elastic buffer and GT. This error occurs continually since GT takes time to recover from reset and is not able to put data into the buffer, and the buffer underflows again. The additional logic makes sure that GT is not reset again if it is already in reset sequence.

Solution

To resolve the issue change gt_reset_rx to include reset_done_rx. In the <core_name>/transceiver.v/vhd file change from:

assign gt_reset_rx = cpllreset | ((!cplllock | (rxreset)) & reset_counter[7]);
to
assign gt_reset_rx = cpllreset | ((!cplllock | (rxreset & resetdone_rx)) & reset_counter[7]);


Linked Answer Records

Master Answer Records

Answer Number Answer Title Version Found Version Resolved
47524 LogiCORE IP Ethernet 1000BASE-X PCS/PMA or SGMII - Release Notes and Known Issues for v11.x N/A N/A
AR# 50328
Date 11/28/2012
Status Active
Type General Article
IP