at wat stage in MAGMA-TALUS should i change cells

[dhivyanandhini]

i would like to replace a FF of a particular pin to reduce the delay in datapath...
At wat stage should i change the FF of a particular pin ???
i tried it after fix clock and then did fix wire and fix opt final....but the slack increased a lot...
can anybody help me in this??

 

[randyest]

i would like to replace a FF of a particular pin to reduce the delay in datapath...
At wat stage should i change the FF of a particular pin ???
i tried it after fix clock and then did fix wire and fix opt final....but the slack increased a lot...
can anybody help me in this??

Can you clarify a bit? What kind of FF are you swapping for what new FF and what is the difference? How do you expect this to improve datapath delay? Does the new FF have less setup time requirement or something? Sorry, your question is not clear to me.

 

[itsmeteja]

swapping can be done at any stage..

Can you slightly elaborate ur query, so that fellow engineers will be able to provide u appropriate soln..

 

[dhivyanandhini]

the FF i want to replace has lesser delay and higher drive strength....

Added after 1 minutes:

i tried to do it before fix clock and found tht the slack of tht path got reduced but i find som other paths slack increased....

 

[huckle]

Higher drive strength cells most likely have bigger input cap, which can cause slew violation for the other cells driving this cell. You need to run a whole round of sizing, re-buffering to fix it.

Thanks,

 

[jeevan.life]

Why dont you do it after fix time? fix cell should be able to take care of the slacks.