We have detected your current browser version is not the latest one. Xilinx.com uses the latest web technologies to bring you the best online experience possible. Please upgrade to a Xilinx.com supported browser:Chrome, Firefox, Internet Explorer 11, Safari. Thank you!

AR# 36328

Aurora 8b/10b 64b/66b - REFCLK error occurs when creating core in different OS than the XCO file


When an XCO file created in a Windows environment is used to create an Aurora core in Linux, or vice versa, the following error might show up:

"ERROR:sim - C_REFCLK_FREQUENCY: Invalid value 'XXX.XX'"

This is caused by the fact that rounding is done differently in each OS. In one OS, a 5 is rounded down, in the other OSit is rounded up. So the problem is when the third digit is a 5.

This can happen in the 8b/10b version, as well as the 64b/66b version, of the Aurora core.


There are two ways to work around this issue:
  • Create the XCO file and the core in the same OS.
  • Edit the c_refclk_frequency parameter in XCO file as per the OS.
This issueis scheduled to be fixed inthe next release of the core; the rounding will automatically be down.
AR# 36328
Date Created 06/22/2010
Last Updated 12/15/2012
Status Active
Type General Article
  • Spartan-6 LXT
  • Virtex-5 FXT
  • Virtex-5 LXT
  • More
  • Virtex-5 SXT
  • Virtex-5 TXT
  • Virtex-6 CXT
  • Virtex-6 HXT
  • Virtex-6 LXT
  • Virtex-6 SXT
  • Less
  • Aurora
  • Aurora 64B/66B
  • Aurora 8B/10B