Re: [SI-LIST] : Routed/unrouted??(Specctraquest)

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From: Patrick Riffault (riffault@cisco.com)
Date: Fri Sep 15 2000 - 09:11:28 PDT


At 09:43 PM 09/15/2000 +0530, Aloke Bhattacharya wrote:
>Hello all,
> When I simulate in Specctraquest using the Analyze>SI/SIM>Probe menu, I
>don't see any option to specify whether to take the actual routed length
>or the manhatton length(I get this option during topology extraction ,
>but I can't see a similar option when I want to do the simulation
>directly in SQ without extracting the topology). Does SQ
>automatically(and intelligently!!) take the actual Etch length for a
>routed net and the manhatton length for an unrouted length?.

Yes it does. Additionally in the preference menu you can set an
option for %manhatten (default is 100) which allows for more or
less length (example 150% manhatten would take the manhatten
length X 1.5). You also specify the default impedance and
prop velocity in that menu.

>I have a similar doubt with the timing spreadsheet- Does the value shown
>in the "propagation" column of the timing spreadsheet(under the
>propagation tab) reflect the actual etch length in case of a routed
>length and manhatton length for an unrouted one? Here also I don't see

It is supposed to, however you have to be cautious of matched lengths
reports in
the spreadsheet for unrouted interconnects. The matching numbers are incorrect
since the signal as not be routed. I think diff pairs have the same problem.
I think the timing spreadsheet is one the most useful utilities in the
"package".
I use it to look at trends and to look at the seriousness of a DRC.

>any option to specify which length to take in case of a routed net.

Again look in the simulation preference menu. I don't remember being able
to or not.

Patrick

>With regards,
>Aloke
>
>--
>**********************************************************************
>* Aloke Bhattacharya, *
>* Senior Engineer-VLSI/System Design,
>* *
>* Wipro Infotech, *
>* Global R&D, *
>* 88, M.G. Road, 5th Floor, *
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>* email: aloke.bhattacharya@wipro.com
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>**********************************************************************
>
>
>
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