[IBIS-Users] RE: BOUNCE ibis-users@eda.org: Non-member submission from [Itz ik Peleg <itzikpe@il.marvell.com>]


Subject: [IBIS-Users] RE: BOUNCE ibis-users@eda.org: Non-member submission from [Itz ik Peleg ]
From: Angulo, John (john_angulo@mentorg.com)
Date: Thu Jan 29 2004 - 19:02:34 PST


The following is posted on behalf of Arpad Muranyi at Intel Corp. Please send any private replies to arpad.muranyi@intel.com.

-----------------------------------

Itzik,

The short answer is that #2 should happen.

Reason: The "NA" in the fall_on_dly and fall_off_dly columns
mean that the falling edge will not trigger anything. Keep in
mind the meaning of an "NA" is not the same as zero delay. "NA"
stands for information is not available, therefore you can't
so anything because you don't know what to do.

You may also look at BIRD 84.1 at

http://www.vhdl.org/pub/ibis/birds/bird84.1.txt

which attempts to clarify some of these issues. The problem is
that there is a minor, but confusing error in the BIRD. The
drawing on the bottom should show the output's falling edges
right under the input's rising edges. I am sending you a fixed
version of the BIRD in the attachment, which I hope we will
post on the IBIS web site shortly.

I hope this helps,

Arpad Muranyi
Intel Corporation
===============================================================

-----Original Message-----
From: owner-ibis-users@eda.org [mailto:owner-ibis-users@eda.org]
Sent: Wednesday, January 28, 2004 1:24 AM
To: owner-ibis-users@eda.org
Subject: BOUNCE ibis-users@eda.org: Non-member submission from [Itzik
Peleg <itzikpe@il.marvell.com>]

To: "ibis-users@eda.org" <ibis-users@server.eda.org>
Subject: Driver schedule interpretation .
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit

Hello IBIS Users

This question regarding the interpretation of driver schedule keyword.
I have made a model using driver schedule keyword. the model is working
fine using one simulation tool.
and don't working (give a completely massy weave form) in another
simulation tool.
When applying to the simulation tool vendor to get his response (and
after some more emails).
I realize that the driver schedule is interpreted differently in the two

simulations tool.
The major difference can be summarize by this question:

When using the [Driver schedule] keyword for example:

    [Driver Schedule]
    |
    | Model name Rise_on_dly Rise_off_dly Fall_on_dly Fall_off_dly
    Out_model 0n 10n NA NA

When the stimulus start rising the model is activated (the pullup of
Out_mode get to on state etc')
If 5ns after the rising of the stimulus, the stimulus have a falling
edge.

Here is the question: What will happen 1 or 2 ?

1. The pullup of Out_model will get into off state (turn off) at 5ns
since the stimulus is falling .
   at 10ns nothing will happen since the pullup is in off state
  (the rise_off_dly has been canceled by the falling stimulus).

2 The pullup of Out_model will stay in on state (turn on) at 5ns.
  at 10ns the pullup of Out_model will go into off state since the
Rise_off_dly time has come.
  (the rise_off_dly isn't canceled by the falling stimulus).

I want an answer by the IBIS committee which will guide how this keyword

should be interpreted in order
that the model maker can make models that will be interrupted correctly
by the EDA tools vendors.

Regards

Itzik Peleg
Board Technology Group

Marvell Semiconductor Israel Ltd
Moshav Manof, D.N. Misgav 20184, ISRAEL
Email - itzik.peleg@il.marvell.com
Tel - +972 4 9951192
Cell - +972 54 452482
Fax - +972 4 9951902
WWW Page: http://www.marvell.com
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