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AR# 34177

11.5 EDK, plbv46_pcie_v4_03_a - Virtex-6 ERROR:PhysDesignRules:1995 - The computed value for the VCO operating frequency of MMCM_ADV instance is calculated to be 500.000000 MHz

Description


The MMCM attribute settings in the  EDK 11.4 core are incorrect. Implementation with ISE/EDK design tools 11.4 will not indicate any error message, but the settings should be updated.
After updating your ISE software to any version greater than 11.4, you will get this error:
ERROR:PhysDesignRules:1995 - The computed value for the VCO operating frequency of MMCM_ADV instance   cgator_wrapper/rport/pcie_clocking_i/mmcm_adv_i is calculated to be 500.000000 MHz. This falls below the operating range of the MMCM VCO frequency for this device of 600.000000 - 1200.000000 MHz. Please adjust either the input frequency CLKINx_PERIOD, multiplication factor CLKFBOUT_MULT_F or the division factor DIVCLK_DIVIDE, in order to achieve a VCO frequency within the rated operating range for this device.

Solution


This error is due to changes in the MMCM requirements, and previous settings used by the core will no longer work in software versions greater than 11.4. This is documented in (Xilinx Answer 33849).
This issue is fixed in plbv46_pcie_v4_04_a, released in EDK 11.5.

Linked Answer Records

Master Answer Records

Answer Number Answer Title Version Found Version Resolved
33849 Virtex-6 FPGA MMCM - New Requirements for all MMCMs, VCO minimum frequency, and CLKFBOUT_MULT_F values N/A N/A

Associated Answer Records

Answer Number Answer Title Version Found Version Resolved
34019 ISE Design Suite 11.4.1 - Known Issues for Virtex-6 FPGA Service Pack N/A N/A
AR# 34177
Date Created 01/21/2010
Last Updated 05/23/2014
Status Archive
Type General Article
Devices
  • Virtex-6 CXT
  • Virtex-6 LX
  • Virtex-6 LXT
  • Virtex-6 SXT
Tools
  • EDK - 11.3
  • EDK - 11.4
  • EDK - 11.5