[IBIS] [Model Selector] Usage


Subject: [IBIS] [Model Selector] Usage
From: Drennan, Steven (steve.drennan@dy4.com)
Date: Fri Oct 25 2002 - 07:00:36 PDT


> Hi all,
>
> I have a bit of a puzzle that I'm trying to figure out as it relates
> to the Model Selector field. Under the [pin] section, there are many pins
> which have been defined with model_name CPU_BUFFER and when I go to find
> out what CPU_BUFFER is, there are 5 other model names as follows:
>
> [model selector] CPU_BUFFER
> CMOS_3_3_BUFF (3.3 when using 3.3V IO voltage)
> CMOS_2_5_BUFF (2.5 when using 2.5V IO voltage)
> CMOS_1_8_BUFF (1.8 when using 1.8V IO voltage)
> HSTL_CLASS1_BUFF (1 HSTL class 1 mode)
> HSTL_CLASS2_BUFF (2 HSTL class 2 mode)
>
> Each one of these models has a submodel and each of those are in good
> shape so my questions are these:
>
> 1) How come when I go into visIBIS, view data and select a signal that
> uses CPU_BUFFER, the model comes up as NC and I can't see any waveforms?
>
> 2) Even if I comment out 4 of the 5 models above, the model is still NC
> and I still can't see any waveforms.
>
> 3) If CPU_BUFFER has 5 models, and this is seen as a programmable buffer,
> where would I set the correct model for each pin?
>
> 4) Why would you use this approach versus assigning the actual pin model
> against the pin?
> i.e. Pin A01=CMOS_2_5_BUFF vs. Pin A01=CPU_BUFFER.
>
> If I can't see the waveforms using model_selector, how am I supposed to
> validate the model reliably?
>
> Thx.
> Steve
>
> ___________________________________
> Steve Drennan, B. Eng
> Components Specialist
> Dy 4 Systems
> Ph: 613.599.9199 x 5246
> Fx: 613.599.7777
>
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