synthesis problem on Design Compiler

[feel_on_on]

design compiler synthesis bottom up vs top down

example : a hierachical design A, top file : my_design.v
include two file : B.v and C.v

Question :
When synthesis , synthesis B.v and C.v individual,then....simply connect them on the top file mydesign.v?


or synthesis directly top file my_design.v ,then......? any suggestion is welcome.

If C.v have two asyn clock, only can synthesis B.v and C.v individually ?

 

[rameshsuthapalli]

Hi,

The synthesis can be done in any way that described. But before that u have to check these things.
1)Is u r design is too big.
2)is there any asycronous paths present in between two design which require some sort of syncronization.
if u r design is too big to handle in one run then do the synthesis of diffrent modules seprately with some sort of care.and integrate them in the top and do the optimisation accross the bounady will solve the problem.
If u r design has syncronous paths where tool need's to take care of syncronisation and ur design is not too big then do the synthsis with top level constraints.other wise follow the previous solution.

regards,
ramesh.s

 

[funster]

the first method is called bottom-up, the second method is called top-down,

if your design is not so large, always use the second method, it will give good

QOR(quality of result).

example : a hierachical design A, top file : my_design.v
include two file : B.v and C.v

Question :
When synthesis , synthesis B.v and C.v individual,then....simply connect them on the top file mydesign.v?


or synthesis directly top file my_design.v ,then......? any suggestion is welcome.

If C.v have two asyn clock, only can synthesis B.v and C.v individually ?

 

[FLEXcertifydll]

for rapid timing closure, U can take bottom-up flow.
synthesis the sub-module firstly, then in top-level, set_dont_touch for the pre-synthesis module, and run synthesis.
It need more work for interface constraints.

 

[littlefield]

read the DC user guide
you will find the answer
search bottom-up , top-down,current_design