Xilinx transceivers have many features that can be used to improve a high speed link.The transmitter can be configured such that it will maximize signal integrity on the link. The receiver can then be configuredto improve its ability to recover data from a link. Below are just a fewof the features available in Xilinx high speed transceivers that can be used to create a more reliable link.
These attributes can be changed to optimize the transceiver to your board configuration. These can greatly increase the margin of a link to reduce the BER. For more information on how these attributes will change the behavior of a link, please see (Xilinx Answer 46892). These features vary across the different device families that have GTs available. Refer to the transceiver user guide for each device familyfor more information on what features are available for a particular device family.
The IBERT tool allows you to change every port and attribute setting available in the transceiver on the fly. This can be very useful since it allows you to instantly see the effect a setting will have on the transceiver.
The only way to determine which transceiver settings will provide an optimal setup is to try out each setting on the board and analyze how it has affected your high speed link. This is a potentially lengthy process since there are a very large number of settings available. Fortunately, the IBERT core has a tool that can automate thistesting process. The sweep test is used to set up a channel test that will sweep through various transceiver settings. At the end of the test, it will provide results of the tests to help you determine which settings will produce.
For more information on the sweep test tool, please refer to the ChipScope User Guide and refer to the "Sweep Test" Section: