Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

How to solve congestion problem after CTS without effecting skew and timing?

Status
Not open for further replies.

designer_ec

Member level 4
Joined
Mar 31, 2007
Messages
68
Helped
1
Reputation
2
Reaction score
0
Trophy points
1,286
Activity points
1,752
Hi,

In my design I got congestion problem after cts. I got congestion at two places in design.Those two places cell density is very high.In design some area having very less cell density.If I move cells from high cell density area to towards less cell density area avoilable in design,but this will effect on skew and timing (because flops also move). Actually this problem occure after optimize the skew.Pls anybody let me know what should I do to solve this problem without efecting skew and timing.
 

congestion

hi designer_ec

I am notsure if this will solve ur prob. Wat can i sugges t u to use soft blockage at high density location there by the buffer are still place and u dont have timmings issues . Try this way ...


Best of luck

Suresh
 

Re: congestion

The soft blockage technique mentioned in the previous reply is an option, but one that should be used only as a last resort because it will have a bad impact on your quality of results.

By the way: Usually we use the term 'utilization' to refer to placement density, and we use the term 'congestion' to refer to routing density. Not a big deal but it helps to be precise.

Most place & route tools understand max utilization limits and will try to avoid creating such hot-spots. Try lowering your maximum allowable utilization limit and redoing the placement from scratch.

You can also try to run a pass of congestion optimization during post-CTS optimization- most P&R tools have this ability.

It seems from your original description that the utilization problem was created by the CTS tool. Get a better CTS tool - a good one won't do this.

Moving a lot of stuff by hand is really a bad idea because it will destroy the quality of your placement.
 

congestion

how do u optimize the skew? CTO?
 

Re: congestion

The skew is largeley determined by CTS. You can optimize the skew 3 different ways:

a) Run CTO after CTS - good for solving significant problems

b) Run CTO after routing - good for correcting routing induced timing problems and fine tuning skew

c) Run some limited useful skew optimization post-route.
 

Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top