Description - Description - 2026.1 English - UG906

Vivado Design Suite User Guide: Design Analysis and Closure Techniques (UG906)

Document ID
UG906
Release Date
2026-06-23
Version
2026.1 English

When a clocking topology uses clocks derived from parallel MMCMs or PLLs, the clock domain crossing is only safe to time if the clock divider (DIVCLK_DIVIDE) of each CMB is set to 1. Any other value removes the phase relationship between the parallel CMBs, making the clock domain crossing asynchronous.