Re: IBIS BIRD63.2 Comments/Questions

Mike LaBonte wrote:
>
> BIRD 63.2 covers a way to document the input signal conditions under
> which a receiver's data book setup and hold timings are specified. But I
> do not see sufficient discussion concerning how an analysis tool is
> expected to use this information.
>
> For example, if a particular simulation shows an input signal that
> differs radically from the conditions under which Tsetup and Thold are
> specified, are we supposed to somehow compensate? If there were multiple
> values of Tsetup and Thold each with a specification of input
> conditions, then the analysis tool could adjust the Tsetup and Thold
> values based on the input conditions seen.
>
> If this BIRD somehow ties to BIRD 61.1, then this should be stated.
> Maybe I will understand it once I read all of these new BIRDs.

At the very least, it provides a correlation point for closing the
timing analysis if the input waveforms DO match the criteria. Which
was not explicit before. (How often have we seen customers measure
input transitions at 0.8v and 2.0v regardless of reality?)

And, yes, BIRD 61.x is an attempt to define the response to nonideal
inputs.

-- 
D. C. Sessions
dc.sessions@vlsi.com