Causes for large -ve slack during pre-place STA

Status
Not open for further replies.
U

useless_skew

Member level 3
Joined
Nov 19, 2007
Messages
63
Helped
16
Reputation
32
Reaction score
10
Trophy points
1,288
Activity points
1,634
If there is a huge -ve slack during pre-placement STA, what is the reason for that?
According to me, it is due to a poorly synthesized netlist or due to some constraints in the timing constraints file.

Is there any other reason for this large -ve slack?

Does the floorplan/macro placement affect pre-placement timing analysis results in any way?

Thanks.
 


Yes, it may due to that not constrainted during synthesis or over constrained or it may be real violation which cant met.

Floorplan and macro placement will make timing worse, not better as synthesis assumes ideal net delay.
 
The very good reason is..The tool will add buffers in unwanted locations so that is the reason most of the people will not go for Preplacement timing analysis..But they will go for Inplacement Optimization....We also had the same situation but later on we came to know

Reply me if u have any doubts..
And don't forget to push help button
Bye take care
 
Status
Not open for further replies.

Similar threads

Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn more…