Subject: [IBIS] RE: [IBIS-Users] ibis pins (once more, this time more details)
From: Douglas Burns (dburns@sisoft.com)
Date: Mon Sep 30 2002 - 05:03:28 PDT
Yoni,
An IBIS model shows only 1 pin. This Pin is the Pin of the chip/package
that connects to the outside world. The stimulus nodes (EN, IN) and the
receiver node (Vout_of_IN) are assumed to exist based upon the model type.
For Hspice, these assumed nodes MUST be specified so that HSPICE can
stimulate them (The nodes in the IBIS pinlist DO NOT fully correlate with
the nodes required by the HSPICE netlist). The model you are using has the
following logical block diagram.
IO PAD
EN ---------
|\ |
| \
IN ------- | x-------------------OUT
| / |
|/ |
|
/| |
Vout_of_IN---- x |----------------
\|
In HSPICE you must specify the simulus for IN and EN. When Enabled, You
apply a 0-->1 transistion to IN to get a 0-->VDDQ transition on OUT.
(The Vout_of_IN input will also toggle from 0-->1
If Disabled, IN is disconnected from OUT, But changes applied to OUT
(0-->VDDQ) will result in a 0-->1 transition on Vout_of_in
Doug
Douglas Burns
Principal Consultant
Signal Integrity Software, Inc.
6 Clock Tower Place
Maynard, MA 01754
978-461-0449
dburns@sisoft.com
-----Original Message-----
From: owner-ibis-users@eda.org [mailto:owner-ibis-users@eda.org]On Behalf Of
Yoni Tzafrir
Sent: Sunday, September 29, 2002 1:54 PM
To: 'Ibis (E-mail); Ibis-Users (E-mail)
Subject: [IBIS-Users] ibis pins (once more, this time more details)
> hi,
> we were trying to connect an sstl2c2_a ibis model, as a reciever. since we
> know this an i/o buffer, we have called for all the i/o buffer nodes to
> our netlist, as specified in this file, on pages 7-16 to 7-19 :
>
> <<2001.4_models_buffers.pdf>>
> in that manner:
>
> * node names nd_pu nd_pd out in en v_out_of_in
> b_output nd_pu nd_pd out pad_r en v_out_of_in
> + file='bsstl2c2_a.ibs'
> + model='bsstl2c2_a'
>
> connecting the in node (called here pad_r), to our circuit.
>
> but looking again in the ibis model once more we saw that there was only
> one pin:
>
> [Pin] signal_name model_name R_pin L_pin C_pin
> 1 PAD bsstl2c2_a NA NA NA
>
> my quesion is what does it mean? is a pin = node? so this model has one
> node only? if so, how do i connect him to the netlist? does'nt that
> contradict the fact that i have called for 5 nodes to my netlist (which
> the hspice runs well, and also refuses to run it with less nodes)?
>
> the file attached above does refer to ibis pin-list in pages 7-44 to 7-50,
> but it is completely unclear to me, and don't answer the questions above.
>
> i'll appreciate your help,
> [Yoni Tzafrir]
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