[ibis] Re: [ibis-users] Re: IBIS model for CPHY MIPI standard

From: Mike LaBonte <mlabonte@xxxxxxxxxx>
To: <aessam@xxxxxxxxx>, <ibis-users@xxxxxxxxxxxxx>, <ibis@xxxxxxxxxxxxx>
Date: Mon, 7 Nov 2016 09:56:58 -0500 (EST)

IBIS does not have quite enough support for dynamic transitions between
enabled and disabled states of the classic IBIS buffer model. The three
states are modeled for static simulation by the I-V tables, and for dynamic
simulation by [Ramp] or the waveforms, and C_comp. But there is no
description of the dynamic transition from the disabled state to either high
or low states. External models could provide the necessary support using AMS
languages, but EDA tools would need to support the stimulus inputs and
output analyses for three states and three wires.

On the other hand a -0.5 to +0.5 two-state digital stimulus is specified for
IBIS-AMI models, which might otherwise be the preferred format for C-PHY.
Specification changes to support both three-level and three-wire C-PHY
signaling using IBIS-AMI seem like a reasonable idea.

This is not to say that some kind of MIPI C-PHY analysis is not being done
today, using the capabilities that EDA tools have built around IBIS and
SPICE. But IBIS purports to support “plug and play” models that can be
confidently used with as many EDA tools as possible.

Mike

From: ibis-users-bounce@xxxxxxxxxxxxx
[mailto:ibis-users-bounce@xxxxxxxxxxxxx] On Behalf Of Ahmed Essam
Sent: Monday, November 07, 2016 9:01 AM
To: ibis-users@xxxxxxxxxxxxx; ibis@xxxxxxxxxxxxx
Subject: [ibis-users] Re: IBIS model for CPHY MIPI standard

Hi Arpad,

Thanks for your reply.I want to clarify some points in your reply as i have
not used External model for IBIS before

Using the external model for creating IBIS for C-PHY will solve the problem
of the third state.So there will be no problem with driving the line to the
midlevel

There is another solution to use "3 state" model in which we use the
receiving state as the third state but it is not supported to simulate that
IBIS model.

Thanks,

Ahmed

On Wed, Nov 2, 2016 at 12:32 AM, <nilesh_kamdar2@xxxxxxxxxxxx> wrote:

Hello Ahmed

Do you have access to Keysight ADS? It can handle MIPI CPHY signals. For
e.g.

This is how the 3 level source is constructed:

And what some of the waveforms look like:

If you are interested in this approach, let me know and I will connect you
with the local Keysight Sales team in your region.

Thanks

Nilesh Kamdar

Applications Engineering

Western District Manager

Keysight EEsof EDA

<http://www.keysight.com/> EmailSig_KST_Transitional-6

From: ibis-users-bounce@xxxxxxxxxxxxx
[mailto:ibis-users-bounce@xxxxxxxxxxxxx] On Behalf Of Ahmed Essam
Sent: Sunday, October 30, 2016 12:57 PM
To: ibis-users@xxxxxxxxxxxxx; ibis@xxxxxxxxxxxxx
Subject: [ibis-users] IBIS model for CPHY MIPI standard

Dear ALL,

I have faced a problem while creating IBIS model for CPHY MIPI standard.The
standard has 3 states on the transmission line (High,Low,Midlevel) .

The transmission line is driven to high state through pull up device,driven
to low state through pull down device,driven to mid level state through both
pull up & pull down devices.

I wonder if IBIS standard can model CPHY standard "driving the transmission
line to 3 states" .

Thanks,

Ahmed

References:
- [ibis] Re: [ibis-users] IBIS model for CPHY MIPI standard
  - From: Ahmed Essam

[ibis] Re: [ibis-users] Re: IBIS model for CPHY MIPI standard

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