Subject: PECL and TTL programmable buffer?

From: Roland Chang <[email-masked]>
Date: Wed, 18 Jun 1997 10:34:33 -0700

Hello, 

thumbing through the BIRDs, I found BIRD30.2, which talks about
programmable buffers.

I have a pair of differential pins, which can accept PECL differential
inputs, or if the (-) pin is grounded, the (+) pin can be used as TTL
Logic level input.

How would I model this in IBIS? would I use programmable buffers? if so,
can you give an example of how I might model this pair of pins using
programmable buffers?

Also,  a general question, how many of the BIRDs are actually
incorporated into the ibischk syntax checker?

thanx,

Roland

******************************************
Roland Chang ext. 2647

PMC-Sierra 
Applications Department
105-8555 Baxter Place
Burnaby, BC
V5A 4V7
Tel: (604) 415-6000

email: [email-masked]
******************************************

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From: [email-masked] ( Bob Ross)
Date: Thu, 19 Jun 1997 13:20:15 -0700 (PDT)

Roland:

Some responses below.

Bob Ross
Interconnectix

> From: Roland Chang <[email-masked]>
> To: "[email-masked]'" <[email-masked]>
> Cc: "[email-masked]'" <[email-masked]>
> Subject: PECL and TTL programmable buffer?
> Date: Wed, 18 Jun 1997 10:34:33 -0700

> can you give an example of how I might model this pair of pins using

I don't think that the BIRD30.2 extension covers situations of 
differential and non-differential inputs.  So I would construct two
IBIS Models, one with differential Inputs and the other without
the differential inputs, and load the appropriate models.

> incorporated into the ibischk syntax checker?

The ibischk2 parser should cover all of the functionality of Version 2.1.
This includes the functionality of Version 1.1 plus BIRDs 1-26 and BIRD29.2.
(Some of these were not approved).  Check
   http://www.vhdl.org/pub/ibis/birds/birddir.txt
for a history and of inclusions of BIRDs into the various Versions of IBIS.