AR# 39756

12.4/13.x ChipScope IBERT - How do I set the Virtex-6 GTH Transceivers in various loopback modes?


ChipScope tool IBERT for GTH Transceivers supports near-end PCS loopback under the "Loopback Mode" pull-down menu, but does not support the near-end PMA loopback (unlike the IBERT for GTX Transceivers). The other type of supported loopback is the Far-end PMA loopback (labeled incorrectly as Far-end PCS loopback)for the GTH transceiver.

This Answer Record explains how to select the variousloopback modes for GTH Transceivers in IBERT.


Near-end PMA Loopback:

The near-end PMA loopback for GTH Transceivers is currently not supported by the IBERT tool, but it can be selected by setting the followingattributes manually through the "DRP Settings" tabin IBERT:

Attribute Value
PMA_LPBK_CTRL_LANE<n>[1:0] 2'b10

It is important to note here thatthough PMA_LPBK_CTRL_LANE<n>[1:0] attributeis perGTH lane,the SLICE_CFG and LANE_AMON_SEL are not lane specific attributes,but affect all four lanes in a Quad. Therefore, all four transceivers in aQuadare placed in near-end PMA loopback mode when these attributes are set to these values. This feature is to be addressed in a future version of the IBERT tool.

Near-end PCS Loopback:

The near-end PCS loopback can be selected from the pull-down menu in the IBERT tool. IBERT sets the following bit to enable the near-end PCS loopback when selected from the menu.

Attribute Value
PCS_MODE_LANE<n>[14] 1'b1

Far-end PMA Loopback:

Far-end PMA loopback is supported in GTH Transceivers, but far-end PCS loopback is not supported. The"Far-end PCS" in the IBERT tool is incorrectly labeled (it is actually far-end PMA loopback), and selecting this option only sets the PCS_MODE<n>[15] bit to 1'b1. The other attribute PCS_RESET<n>[1] is not set correctly either.This feature is to be addressed in a future revision of the IBERT tool.

Attribute Value
PCS_MODE_LANE<n>[15] 1'b1
PCS_RESET_LANE<n>[1] 1'b0

The far-end PMA loopback can be selected correctly by setting the above attributes manually through the "DRP Settings" tab in IBERT.



Answer Number 问答标题 问题版本 已解决问题的版本
40485 13.x ChipScope Pro - Known Issues for the ChipScope Pro 13.x Software N/A N/A


Answer Number 问答标题 问题版本 已解决问题的版本
38596 Virtex-6 FPGA GTH Transceiver - Known Issues and Answer Records List N/A N/A
35269 12.x ChipScope Pro - Known Issues for the ChipScope Pro 12.x software N/A N/A
AR# 39756
日期 01/02/2013
状态 Active
Type 综合文章