Questions of Polarity and Enable

Hi, Ibis folks:

Can anyone tell me what the sub-param Polarity and Enable of
keyword [Model] really means? Is Polarity used only on diff
pins? Is Enable used only on tri-state pins? How can I decide
the Polarity and Enable of an input or output pin?

I can't find such detail information from IBIS2.1 Specification,
can anyone give me some advices, or tell me where i can find
the answer?

Thanks a lot,

-Zheng Shi
 zheng@symmetry.com
 Los Altos, CA.
Received on Thu Dec 5 17:45:16 1996