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AR# 52135

LogiCORE IP Ethernet 1000BASE-X PCS/PMA or SGMII v11.4 - 7 Series - 500 ns delay needed for GTTXRESET and GTRXRESET


The 7 Series GTX/GTH Transceivers require a 500 ns delay before asserting GTTXRESET and GTRXRESET after configuration. 

This reset requirement is described in the GTX/GTH Transceiver Users Guide and in (Xilinx Answer 43482).

This delay was correctly applied in the previous v11.3 Ethernet 1000BASE-X PCS/PMA or SGMII core.


The delay can be added by making the following change in the example_design/transceiver/core_name_transciever.v/vhd file.

If using Verilog change:

   assign gt_reset_rx = !cplllock || (rxreset_int & resetdone_rx);
   assign gt_reset_tx = !cplllock || (txreset_int & resetdone_tx);


   assign gt_reset_rx = rxreset_int & resetdone_rx;
   assign gt_reset_tx = txreset_int & resetdone_tx;

If using VHDL change:

   gt_reset_rx <= not cplllock or (rxreset_int and resetdone_rx);
   gt_reset_tx <= not cplllock or (txreset_int and resetdone_tx);


   gt_reset_rx <= (rxreset_int and resetdone_rx);
   gt_reset_tx <= (txreset_int and resetdone_tx);

AR# 52135
Date Created 10/01/2012
Last Updated 09/08/2014
Status Active
Type General Article
  • Ethernet 1000BASE-X PCS/PMA or SGMII