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AR# 45075

Virtex-6 FPGA GTH Transceivers - Wizard v1.9 incorrectly sets GTH Transceivers in PMA loopback by default

Description


The Virtex-6 FPGA GTH Transceivers are placed in PMA loopback mode by default in Wizard v1.9 released with ISE Design Suite 13.3.

This answer record explains how to disable this loopback so that the GTH Transceivers can be placed in a normal operation mode.

Solution


Virtex-6 FPGA GTH Transceiver Wizard v1.9 sets the PMA_LPBK_CTRL_LANEx[1:0] to 2'b10 by default.

As documented in Table 2-15 of the Virtex-6 FPGA GTH Transceivers User Guide (UG371), this value sets the GTH Transceiver in TX pre-driver PMA loopback mode: http://www.xilinx.com/support/documentation/user_guides/ug371.pdf

To disable the loopback mode, this value should be changed to 2'b00.

This is fixed in v1.10 of the Virtex-6 FPGA GTH Transceiver Wizard released with ISE Design Suite 13.4.
AR# 45075
Date Created 11/28/2011
Last Updated 03/27/2012
Status Active
Type General Article
Devices
  • Virtex-6 HXT
Tools
  • ISE Design Suite - 13.3
IP
  • Virtex-6 FPGA GTH Transceiver Wizard