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AR# 50962

Soft Error Mitigation Core v3.2 - The XDC set_max_delay constraints are incorrect


The Soft Error Mitigation (SEM) IP v3.2 used an XDC constraint 'set_max_delay'. The constraint was incorrect, resulting in unconstrained paths. This issue was corrected in the SEM IP v3.3, released with Vivado 2012.2.


The SEM IP v3.2 used an XDCconstraint 'set_max_delay' to constrain timing between the FRAME_ECC primitive start points and various timing end points. This constraint was written incorrectly, which resulted in unconstrained timing paths.

These constraints have been corrected forv3.3 of the core. Use the new set_max_delay constraints, as generated in the IP's example XDC constraints file.

Below is an example of the syntax, but the actual numbers will be based on the user's specified clock frequency. For a 70 MHz clock, the set_max_delay constraints would be:

  • set_max_delay 11.285 -from [get_pins example_cfg/example_frame_ecc/*] -quiet
  • set_max_delay 28.57 -from [get_pins example_cfg/example_frame_ecc/*] -to [all_outputs] -quiet

Linked Answer Records

Master Answer Records

Answer Number Answer Title Version Found Version Resolved
44541 Soft Error Mitigation Controller - Release Notes and Known Issues for v1.1 to v3.4 N/A N/A
AR# 50962
Date 02/07/2013
Status Active
Type Known Issues
  • Vivado
  • Soft Error Mitigation