[SI-LIST] Re: driver schedule in hspice
- From: "Muranyi, Arpad" <arpad.muranyi@xxxxxxxxx>
- To: <si-list@xxxxxxxxxxxxx>
- Date: Wed, 17 Aug 2005 08:49:27 -0700
Terence,
The [Driver Schedule] keyword is a difficult one. If you
looked at the list of BIRDs on the IBIS web site, you will
find that there were a lot of "clarifications" done in the
past few years. I am not surprised that there may be
differences in how tool vendors implemented it.
However, I believe that the latest version of the IBIS
specification is pretty clear now, and there should be
no confusion about how it should work. It is a different
question whether the tool vendors have actually made any
changes to their implementations to match what the latest
version of the spec says.
Also, model makers may have their own understanding (or
misunderstanding) of the keyword, so they may expect something
different from what they get from the tool. I didn't study
your model and your expectation deeply, so I can't say whether
Cadence or HSPICE is correct, but it doesn't mean that the
Cadence implementation is the right one just because Cadence
gives you what you expect. In fact, I have worked with the
HSPICE developer more than with Cadence, and from that I
would tend to say that HSPICE does what the IBIS specification
says (unless you found another bug, that is).
Sorry for the long answer, but I was trying to respond to your
question: "Is this is a common problem?".
Arpad
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
=20
-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] =
On Behalf Of TerenceHsieh@xxxxxxxxxxxx
Sent: Wednesday, August 17, 2005 12:09 AM
To: si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] driver schedule in hspice
Dear all
I have a question about driver schedule. When I generate an
ibis file with [driver schedule] to obtain de-emphasis and put it in=20
Sig-xp to do simulation. Because my longest pattern is 5UI
(UI=3D400ps),for example 101011111010100000.
I set the driver schedule as follow
[Driver Schedule]
|Model_name rise_on_dly rise_off_dly fall_on_dly fall_off_dly
pu_full 0ps 400ps NA NA
pu_sing 400ps 2000ps NA NA
pd_full NA NA 0ps 400ps
pd_sing NA NA 400ps 2000ps
=20
the simulation in Sig-xp is normal. New trigger will cancel everything
that happened before.
However, when I using the same IBIS file in Hspice. The result will
change
New trigger will not cancel what happened before and the output waveform
will not as my expectation.
What I can do is to use symmetrical pattern and modify my driver
schedule setting..
For example, if I want to simulate pattern 110011001100, I must adjust
driver schedule as follow
[Driver Schedule]
|Model_name rise_on_dly rise_off_dly fall_on_dly fall_off_dly
pu_full 0ps 400ps NA NA
pu_sing 400ps 800ps NA NA
pd_full NA NA 0ps 400ps
pd_sing NA NA 400ps 800ps
=20
and for other pattern 111000111000111000, I must adjust driver schedule
again.=20
Is this is a common problem? If I using ibis in hspice, can't I using
arbitrary pattern as 101011111010100000?
How could I solve this problem, thanks.
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