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
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
説明
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.
ソリューション
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.