ASIC Design Flow ? please clarify my confuse ..............?

[kbkdec15]

HI everyone ,


when will Pre synthesis and post synthesis come in ASIC Design flow?
when will Pre validation and post validation come in ASIC Design flow?

why should we need pre and post (synthesis and validation ) ? what is difference between validation and testing ?

when should we neglect STA in ASIC Design flow ?
does every design need Dynamic timing analysis or not ?

DTA used for combinational circuit , STA used for sequential. i mean the design contains both comb and sequential circuits . so, does any one of the Timing Analysis enough or both require ?


please clarify me

thanks
kbkdec15

 

[rca]

Well I don't understand your question?
The STA means statistic timing analysis, and cover all timings combinational and sequential timing.
What is for you a pre and post validation for backend flow?
What is for you a pre and post synthesis for backend flow?
For the backend ASIC flow:
1- synthesis
2- placement
3- clock tree
4- fix hold time
5- routing
6- SI fix
7- STA

 

[kbkdec15]

Hi rca,

thanks

i have heard about various words like pre synthesis , post synthesis , pre validation and post validation. but i do not know when they would come in design flow .


please can you explain those words and related information


regards
kbkdec15

 

[maulin sheth]

Pre Synthesis means - The process which is done before doing the synthesis.
Post Synthesis : The process which is done after synthesis..

mostly pre and post means that before and after respectively.

STA : is just static timing analysis means, it will not apply any patterns to design, but just doing the timing analysis for 0->1 and 1->0 transitions on net and logic.
While DTA : is just simulation with patterns. So we can check that, Timing analysis which is done by STA is working fine or not..

I don't think that there is any difference between testing and validation.

Thanks
Maulin

 

[kbkdec15]

Pre Synthesis means - The process which is done before doing the synthesis.
Post Synthesis : The process which is done after synthesis..

mostly pre and post means that before and after respectively.

STA : is just static timing analysis means, it will not apply any patterns to design, but just doing the timing analysis for 0->1 and 1->0 transitions on net and logic.
While DTA : is just simulation with patterns. So we can check that, Timing analysis which is done by STA is working fine or not..

I don't think that there is any difference between testing and validation.

Thanks
Maulin

hi maulin sheth,

thank you.

generally what we will do in pre-synthesis and post synthesis.

i think ,To get 0->1 or 0-> transitions , should apply for some pattern only.

how STA is differ from DTA ?


Regards
kbkdec15

 

[maulin sheth]

I already mentioned the difference between STA and DTA...
STA is only done from flop to flop , i/p to flop, o/p to flop etc....STA is not done on the full circuit...
While DTA is done from Top level in to top level o/p...DTA is done by pattern simulation...While STA is not required any patterns.

In STA, we don't require patterns for 0->1 and 1->0 transition, STA is just for calculation of almost all types of delays...
As you knw that, delay = RC , so for calculating Capacitance, we need 0->1 and 1->0 transition. That's it..
I think if you are more interested thn try to get the book : STA for nano meter design...or you will find lots of material on net...

 

[kbkdec15]

hi maulin sheth ,

thank you very much. i will follow your guidelines

regards
kbkdec15

 

[loveheihei]

we need pre and post because we can not clearly know the qor of the design, and the simulation is maybe only functional, so we need to do it again and again to make sure of it.