The Clocking Wizard selects optimal settings for the parameters of the
clocking primitive. You can override any of these calculated parameters as per your
requirement. When the Allow Override mode is selected, the overridden values are used as
primitive parameters instead of the calculated values. The wizard uses the settings for
timing calculations, and any settings changed here are reflected in the summary
pages.
Important: It is important to verify that the values you are choosing to
override are correct because the wizard implements what you have chosen even if it
causes issues with the generated network.
Parameters listed are relevant for
the physical clocks on the primitive, rather than the logical clocks created in the
source code. For example, to modify the settings calculated for the highest priority
CLK_OUT1, you must modify CLKOUT0* parameters, and not the CLKOUT1*
parameters for a MMCM or PLL.