[SI-LIST] Re: Flight time compensation

Fair enough ... But in reference to Subramanyi's question about an SDRAM
at 133 MHz (rather than DDR2, for example), the timing will be more
straighforward with min and max measurements taken between the high and
low logic thresholds at the receiver and the timing test load waveform
at Vmeas.

My .79 Rupees ...

Bill Hargin
High-Speed Marketing Manager
Mentor Graphics Corp.
Systems Design Division
425-301-4425 - Mobile=20

> -----Original Message-----
> From: si-list-bounce@xxxxxxxxxxxxx=20
> [mailto:si-list-bounce@xxxxxxxxxxxxx] On Behalf Of Todd Westerhoff
> Sent: Thursday, October 18, 2007 11:57 AM
> To: si-list@xxxxxxxxxxxxx
> Subject: [SI-LIST] Re: Flight time compensation
>=20
> Bill,
>=20
> One point worthy of note - properly measuring a flight time=20
> for use in timing analysis requires accounting for both the=20
> driver's reference load **AND** measuring input crossings at=20
> the receiver in accordance with the receiving device's setup=20
> and hold specifications.  The flight time adjustment you're=20
> talking about here only goes to driver reference load=20
> compensation, which is usually the easier of the two problems.
>=20
> My $0.02.
>=20
> Todd. =20
>=20
> Todd Westerhoff
> VP, Software Products
> SiSoft
> 6 Clock Tower Place, Suite 250
> Maynard, MA 01754
> (978) 461-0449 x24
> twesterh@xxxxxxxxxx
> www.sisoft.com
> -----Original Message-----
> From: si-list-bounce@xxxxxxxxxxxxx=20
> [mailto:si-list-bounce@xxxxxxxxxxxxx] On Behalf Of Hargin, Bill
> Sent: Thursday, October 18, 2007 12:38 PM
> To: kpsubramani@xxxxxxxxx; si-list@xxxxxxxxxxxxx
> Subject: [SI-LIST] Re: Flight time compensation
>=20
> Hi Subramanyi:
>=20
> In the HyperLynx Help system (I'm looking at HL7.7) under=20
> "Simulating Entire Boards or Multiple Nets > Reference=20
> Information for Batch Simulation > Flight-Time Compensation,"=20
> you'll find a pretty extensive description on this subject.=20
> (Or, just search on "Flight-Time
> Compensation.")
>=20
> Compensation for loading effects is accounted for in an=20
> automated measurement (Flight Time button at the bottom of=20
> the scope in 7.7), and in batch mode, as long as the IBIS=20
> models have all of the proper Cref, Rref, Vref, and Vmeas=20
> parameters. (Fortunately, most models do.)
>=20
> > Can I use batch simualtion to simulate bunch of addr/data lines
>=20
> There's a spreadsheet output from batch simulation that=20
> includes flight times.
>=20
> Bill Hargin
> High-Speed Marketing Manager
> Mentor Graphics Corp.
> Systems Design Division
> 425-301-4425 - Mobile=3D20
> =3D20
>=20
> > -----Original Message-----
> > From: si-list-bounce@xxxxxxxxxxxxx=3D20
> > [mailto:si-list-bounce@xxxxxxxxxxxxx] On Behalf Of sub mani
> > Sent: Wednesday, October 17, 2007 5:36 PM
> > To: si-list@xxxxxxxxxxxxx
> > Subject: [SI-LIST] Flight time compensation =3D20  Hello all, =3D20  =
I=20
> >have a SDRAM connected to a controller. The SDRAM operates=3D20  at=20
> >133MHz.=3D20  I am using hyperlynx for analysis.
> >=3D20
> > I am also using timing designer to check the setup and=20
> hold=3D20  time=20
> >margin From Hyperlynx I want to derive the delays due to=3D20 =20
> >transmission line and apply those delays to timing designer I=3D20 =20
> >wanted to know the procedure for doing that. Should I=3D20  =
compensate=20
> >for the flight time and what are all the data that=3D20  I should use =

> >from hyperlynx simulation to add to the signal=3D20  delay in timing=20
> >designer to accurately calculate the time=3D20  margin Can I use =
batch=20
> >simualtion to simulate bunch of addr/data lines =3D20  thanks=20
> in advance =20
> >subramani =3D20 =3D20 =3D20 =3D20 =3D20 =3D20
> >       ___________________________________________________________
> > Yahoo! Answers - Got a question? Someone out there knows the=3D20 =20
> >answer. Try it now.
> > http://uk.answers.yahoo.com/
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