[SI-LIST] Re: hspice questions
- From: "Yang, Long" <long.0.yang@xxxxxxxxx>
- To: "Siva kumar" <sivakumar_skm@xxxxxxxxx>
- Date: Wed, 19 Mar 2008 09:04:32 +0800
And when you finish the hpsice simulation, you need view the waveform of eye
in avanti.
Pay attention to setting viewing parameters correctly in avanti
On Wed, Mar 19, 2008 at 9:01 AM, Yang, Long <long.0.yang@xxxxxxxxx> wrote:
> Hi, Kumar:
> Here is Hspice code for generating Eye-diagram (you need to change some
> parameters according to your req)
> * .param eyefreq=625e6 per='1/eyefreq' $ max toggle lvds rate
> .param Tshift=1.55n
> eT T 0 VOL='((TIME-Tshift)*(eyefreq/2))-int((TIME-Tshift)*(eyefreq/2))'
> rT T 0 1k
> .print tran v(t)*
>
> On Wed, Mar 19, 2008 at 12:42 AM, Jim (James) Antonellis <
> janton@xxxxxxxxxxxx> wrote:
>
> >
> > Hi Siva,
> >
> > Many ways to "skin the cat", here are a couple:
> >
> > If you have Cscope with your HSPICE (CosmosScope is a waveform viewer
> > also a Synopsys product) you can easily plot Eye Diagrams and measure the
> > zero-crossing of all transitions. Avanwaves is an older Synopsys waveform
> > viewer that can alos plot Eye diagrams and give you the zero crossing
> > measurement.
> >
> > In regards to "sweeping" multiple parameters, Using the ".Data" and
> > ".ALTER" HSPICE constructs you can get any nested loop parameter sweep
> > youdesire!
> >
> > For example (this is only psuedo code from memory):
> >
> > .tran STEP END sweep =3D foobar
> > .DATA foobar
> > param1 param2
> > x y
> > m n
> > a b
> > .ENDDATA
> >
> > .ALTER
> > .del lib SLOW_PVT
> > .lib FAST_PVT
> >
> >
> > This example will produce 6 runs. The inner loop (.DATA) provides 3
> > sweeps=20 of param1 and param2. The outer loop (.ALTER) will add a second
> > run with a change in my process lib.
> >
> > Jim Antonellis=20
> >
> > janton@xxxxxxxxxxxx
> > Broadcom Corp www.broadcom.com
> >
> > Office: 978.689.1669
> > Cell: 978.618.4745
> >
> > -----Original Message-----
> > From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx]
> > On Behalf Of Siva kumar
> > Sent: Tuesday, March 18, 2008 11:50 AM
> > To: si-list@xxxxxxxxxxxxx
> > Subject: [SI-LIST] hspice questions
> >
> > ladies and gentlemen,
> > i am a newbie to Hspice and i have few questions on it.
> >
> > 1. I have a differential clock output and i would like to measure the
> > signal crossing points (the time at which the clk_p and clk_n crossing
> > event occurs.). I went thru the user manuals and tutorials. Though there are
> > bunch of info on .MEASURE command, but i couldnt find a method to find the
> > crossing of clk_p and clk_n. these values i need it to do the timing
> > analysis.
> >
> > 2. My signals operates at 400mbps and i would like to generate the eye
> > diagram. how to do that using hspice. can anybody give info on that?
> >
> > 3. I have one more question on Paramater sweep. I need to sweep
> > twovariables in my circuit.=20
> >
> > For example,
> >
> > .tran 0.01ns 20ns sweep length1 100 1000 100 .tran 0.01ns 20ns sweep
> > length2 500 1000 250
> >
> > i tried like above but always i am seeing only one variable in the
> > waveform.( if i sweep var1 and var2 using the above method, tr1 and tr2
> > results with var1 displayed but i dont know for which value of var2 the
> > sweep happened..
> >
> > The objective is, i am doing the SI analysis and i want to sweep the
> > tracelengths of the topology. I want to try like the following for loop and
> > print both length1 andlength2.=20
> >
> > for length1=3D100 to 1000 step 100
> > {
> > for length2=3D500 to 1000 step 25
> > }
> >
> > thanking you in advance.
> >
> > Also i would appreciate if anybody can share any advanced / complex
> > examples on SI analysis using hspice that helps to improve the efficiency
> > and saves time.
> >
> > thanks,
> > kumar
> >
>
--
I am blogging at
http://lyoung.blogcn.com
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