Re: Help: Programable outputs

From: Syed Huq <huq@rockie.nsc.com>
Date: Wed Dec 04 1996 - 16:29:10 PST

Scott,

I have a device with a programmble slew rate spec. Slew rate is controlled
by an external pin tied to a variable resistor. There are may ways to do this
until we see Arpad's BIRD30.2(Programmable Buffer)in IBIS3.0. So,we have to figure
work arounds til then.

I added ALL the possible buffer combinations in ONE IBIS model file. THen thru
the pin list, I comment out the model names I do not need to run. This manual
commenting and uncommenting of model names need to be explained up on top
under [Notes] for a customer to understand what to do.

Best Regards,
Syed.
National Semiconductor Corp.

>
> For a component that has a programable behavior for the I/O pins, what
> might be the preferred way of presenting the data for the different
> possible configurations? Specifically, let's say that a pin can be
> programmed to be either:
> 1) Tristateable I/O with a fast slew rate
> 2) " " " " slow slew rate
> 3) Open Drain output (data input to the output buffer is
> programmed to be tied to the enable of the buffer)
>
> Would it be better to actually make a main IBIS file that contains all
> of the I/Os in condition (1), with 2 extra IBIS files that contain only
> one pin in them each for conditions (2) and (3)? Or, perhaps only make
> one IBIS file with all of the pins configured in condition (1) and
> commented out sections for conditions (2) and (3). Or, even another
> possibility of dividing the I/Os into 3 equal sections, one for each
> configuration? All comments/suggestions welcome, and please forgive me
> if this has been discussed already. Thanks,
Received on Wed Dec 4 16:39:23 1996

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