I receive the message below when i run post-layout simulation with back annotation in VCS:
"SDF error: cannot find timing check"
Can anyone tell me how to solve this problem?
That means that the cell library that you are using for simulation does not contain the timing check that is present in the SDF and is being annotated - or it may be present in the library, but timing checks are not enabled during compile time. The timing checks in the library are in the 'specify' block...
So i think the problem is: the cell library have not define the RECOVERY parameter (in specify block). Is that right?
The question is how to solve this error? Thank you!
Yes, that's right. Go take a look. Also, the SDF files from version 2.1 and 3.0 vary a bit. The cell library may be based on a different version than the SDF file. You'll find the version of the SDF file at the top of the file.
Yeah, my SDF file is 2.1 version.
But what can i do to solve the problem? Should i:
-Ignore the error (if this error is not important)
-Or find a different version of library cell (if this error is important)
Could you suggest me a solution?
Thank you very much!
You should probably take a look a the library, and see if it has a $recrem timing check specified (recrem = RECoveryREMoval). if so, most likely it supports sdf 3.0, and the best course of action is to try to output the sdf in 3.0 format. It may also be that the library spports both, but requires a compile-time switch to conform to one or the other. if there is no $recovery OR $recrem in the specify block, then just ignore it. But that's the last resort. The synthesis library and simulation library should not be that far off..
when u r compiling the library cells, u can use the options like timing check for simulation perpose afterwords check back annotation happen properly or not