Clock Fall Output Delay Command Option - 2023.2 English

Vivado Design Suite User Guide: Using Constraints (UG903)

Document ID
Release Date
2023.2 English

The -clock_fall option specifies that the output delay constraint applies to timing paths captured by a falling clock edge of the relative clock. Without this option, the Vivado IDE assumes only the rising edge of the relative clock (outside the device) by default.

Do not confuse the -clock_fall option with the -rise and -fall options. These options refer to the data edge not the clock edge.