When using ISE 11.5 to simulate a v1.4 wrapper generated in ISE 11.4, simulation will fail with the following error message:
Attribute Syntax Error : The calculation of VCO frequency=500.000000 Mhz. This exceeds the permitted VCO frequency range of 600.000000 Mhz to 1600.000000 Mhz. The VCO frequency is calculated with formula: VCO frequency = CLKFBOUT_MULT_F / (DIVCLK_DIVIDE * CLKIN1_PERIOD). Please adjust the attributes to the permitted VCO frequency range.
Xilinx recommends regenerating the core using ISE 11.5. This will generate v1.4 rev 2 of the core in which this problem will be fixed.
Revision History
03/08/2010 - Initial Release