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AR# 37784 Virtex-6 FPGA Integrated Block for PCI Express - x8 Gen 2 Timing Closure

Version Found: v2.1, v1.1
Version Resolved and other Known Issues: See (Xilinx Answer 45723).

A TIG constraint and optional block RAM pipelining can be added to ease x8 Gen 2 timing closure.

Add the following constraints to the UCF file:

PIN "core/pcie_clocking_i/GEN2_LINK.pipe_clk_bufgmux.CE0" TIG;
PIN "core/pcie_clocking_i/GEN2_LINK.pipe_clk_bufgmux.CE1" TIG;

Also, enabling pipeline registers on the read and write side of the Transaction Block RAM can help. To perform this, on page 10 of the CORE Generator Customization GUI, select the option for "Buffer Write and Read".

Pipeline Registers for Transaction Block RAM Buffers = Buffer Write and Read

Revision History
01/18/2012 - Updated; added reference to 45723
07/06/2011 - Updated for v2.4 and ISE 13.2 software release
02/03/2011 - Updated for v2.3 and v1.7 release
12/24/2010 - Updated for v2.2 release
10/11/2010 - Added constraint for CE0 pin
10/05/2010 - Updated for v1.6 release
09/02/2010 - Added note about pipeline registers
08/31/2010 - Initial Release

NOTE: "Version Found" refers to the version the problem was first discovered. The problem might also exist in earlier versions, but no specific testing has been performed to verify earlier versions.

AR# 37784
Date Created 08/31/2010
Last Updated 05/20/2012
Status Active
Type Known Issues
Devices
  • Virtex-6 CXT
  • Virtex-6 HXT
  • Virtex-6 LXT
  • Virtex-6 SXT
Tools
  • ISE Design Suite - 12.1
  • ISE Design Suite - 12.2
IP
  • Virtex-6 FPGA Integrated Block for PCI Express ( PCIe )
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