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AR# 36957

LogiCORE IP Ethernet 1000BASE-X PCS/PMA or SGMII v10.5 - GMII setup/hold errors seen when targetting Virtex-6 HXT

Description


There is a timing failure (setup/hold) issue on the GMII interface of the example design when the following options are used:
 
  • 1000BASE-X mode (not SGMII)
  • TBI
  • Virtex-6 HXT subfamily

The failure is caused by an update to the speed files for the HXT family in 12.2.

Solution

This issue has been fixed in v10.5 rev1 of the 1000BASE-X PCS/PMA or SGMII core.

Rev1 of the core can be installed by downloading the patch available in (Xilinx Answer 36674)

To fix the issue, you need to edit the UCF file.

Identify the DELAY_VALUE constraints which are applied to the GMII Rx signals:

#-----------------------------------------------------------
# To Adjust GMII Tx Input Setup/Hold Timing                -
#-----------------------------------------------------------


INST "delay_gmii_tx_en"  IDELAY_VALUE = "20";
INST "delay_gmii_tx_er"  IDELAY_VALUE = "20";

INST "gmii_data_bus[7].delay_gmii_txd"  IDELAY_VALUE = "20";
INST "gmii_data_bus[6].delay_gmii_txd"  IDELAY_VALUE = "20";
INST "gmii_data_bus[5].delay_gmii_txd"  IDELAY_VALUE = "20";
INST "gmii_data_bus[4].delay_gmii_txd"  IDELAY_VALUE = "20";
INST "gmii_data_bus[3].delay_gmii_txd"  IDELAY_VALUE = "20";
INST "gmii_data_bus[2].delay_gmii_txd"  IDELAY_VALUE = "20";
INST "gmii_data_bus[1].delay_gmii_txd"  IDELAY_VALUE = "20";
INST "gmii_data_bus[0].delay_gmii_txd"  IDELAY_VALUE = "20";


Change all of the "20" values to "22" to obtain the following:

#-----------------------------------------------------------
# To Adjust GMII Tx Input Setup/Hold Timing                -
#-----------------------------------------------------------
INST "delay_gmii_tx_en"  IDELAY_VALUE = "22";
INST "delay_gmii_tx_er"  IDELAY_VALUE = "22";

INST "gmii_data_bus[7].delay_gmii_txd"  IDELAY_VALUE = "22";
INST "gmii_data_bus[6].delay_gmii_txd"  IDELAY_VALUE = "22";
INST "gmii_data_bus[5].delay_gmii_txd"  IDELAY_VALUE = "22";
INST "gmii_data_bus[4].delay_gmii_txd"  IDELAY_VALUE = "22";
INST "gmii_data_bus[3].delay_gmii_txd"  IDELAY_VALUE = "22";
INST "gmii_data_bus[2].delay_gmii_txd"  IDELAY_VALUE = "22";
INST "gmii_data_bus[1].delay_gmii_txd"  IDELAY_VALUE = "22";
                INST "gmii_data_bus[0].delay_gmii_txd"  IDELAY_VALUE = "22";

Linked Answer Records

Master Answer Records

AR# 36957
Date Created 07/23/2010
Last Updated 09/08/2014
Status Active
Type General Article
Devices
  • Virtex-6 HXT
Tools
  • ISE Design Suite - 12.2
IP
  • Ethernet 1000BASE-X PCS/PMA or SGMII