AR# 45513

Description

The following error occurs in MAP:

ERROR:LIT:693 - Block 'MMCME2_ADV symbol
   "physical_group_inst_dl_group/inst_dl_dacif/inst_dl_dacif_core/inst_dac_ddrio
   _lvds/U0/clkfbout/inst_dl_group/inst_dl_dacif/inst_dl_dacif_core/inst_dac_ddr
   io_lvds/U0/mmcm_adv_inst"' has its target frequency, FVCO, out of range.
   Valid FVCO range varies depending on speed grade: 600MHz - 1200MHz(-1),
   600MHz - 1440MHz(-2), 600MHz - 1600MHz(-3). The computed FCVO is a function
   of the input frequency CLKIN1_PERIOD, the division factor DIVCLK_DIVIDE, and
   the CLKFBOUT_MULT_F attribute (FVCO =
   1000*CLKFBOUT_MULT_F/(CLKIN1_PERIOD*DIVCLK_DIVIDE)). The CLKIN_PERIOD
   attribute may have been set by ngdbuild based on the user specified PERIOD
   constraint. The current calculated FVCO is 3072.000315 MHz.

The following is from the VHD generated by clocking wizard:

For these given parameters, the calculated FVCO is 1000MHz, which is within the valid range.

Why does the error occur?

Solution

Please pay attention to the PERIOD specification for the MMCM's CLKIN1 in UCF. 

The value overrides the coregen customization.

In this example, the PERIOD has been set as 307.2MHz, which results in FVCO being over 3000MHz.

You need to modify UCF to match the clock input specification.