CDC Synchronizers and ASYNC_REG Property - 2021.2 English

Vivado Design Suite User Guide: Using Constraints (UG903)

Document ID
UG903
Release Date
2021-11-17
Version
2021.2 English

Xilinx recommends that all synchronizer flip-flops have their ASYNC_REG property set to true in order to preserve the synchronizer cells through any logic optimization during synthesis and implementation, and to optimize their placement for best Mean Time Between Failures (MTBF) statistics. For any clock group constraints that are enabled in both tables (either by default or by the user), the wizard sets to true any missing ASYNC_REG property.

Refer to the Vivado Design Suite Properties Reference Guide (UG912) for detailed information about the ASYNC_REG property.