As part of the design constraints, the waivers are automatically saved inside the checkpoint and restored from the checkpoint. Waivers are saved inside both the plain XDC and binary constraints.
write_waivers commands to export the waivers as a standalone XDC file. The XDC can be reloaded inside Vivado tools with the
write_xdc command exports all the waivers inside the XDC file along with all the design constraints. This includes the waivers defined by the user and also the Xilinx IP waivers. The constraints inside the XDC are in the same order as they have been applied to the design. To only export the waivers, use the command line option
waiver. For example:
write_xdc -type waiver -file waivers.xdc
create_waiver -internal. User waivers must never use the option
create_waiver -internal. This option is exclusively reserved for Xilinx IP waivers.
write_waivers command differs from
write_xdc because it only exports the user waivers and provides more control and granularity. The Xilinx IP waivers are not exported through
write_waivers. By default, all the user CDC, DRC, and Methodology waivers are exported. Use the option
-type to only export CDC, DRC, or Methodology waivers.
For example, the command below exports all CDC waivers to the file waivers_cdc.xdc:
write_waivers -type CDC -file waivers_cdc.xdc
All the waivers for a particular check id can be exported with the option
-id. The example below export all the waivers for the Methodology check TIMING-15:
write_waivers -id TIMING-15 -file waivers_timing_15.xdc
The following table summarizes the differences between
write_waivers commands with regards to the user waivers and Xilinx IP waivers.
|Vivado Command||Export User Waivers||Export Xilinx IP Waivers|