RE: XAUI Driver Spec
Thank you for brigning this up, Robbie. The 1.6V idea was floated in Austin
as it was at the XAUI breakout in New Orleans and there were no objections
in either case. I expect that it will come up again and be officially moved
in Tampa, so now is a good time to express concerns. I encourage other
receiver designers to consider the implications and come prepared with an
opinion.
-Dawson
-----Original Message-----
From: Robbie Shergill [mailto:Robbie.Shergill@xxxxxxx]
Sent: Friday, November 03, 2000 6:57 AM
To: stds-802-3-hssg@xxxxxxxx
Subject: XAUI Driver Spec
Hello all,
Last week in Austin the XAUI group decided to change Max Diff. Amplitude to
1.6 volts. As I understood it, the rationale for increasing the max
amplitude
was to achieve commonality with the Infiniband spec. Although I agree with
the spirit of this rationale, I checked the Infiniband spec and found
that they are trying to drive a cable as well as a backplane with one
electrical specification; thus the reason for the 1.6v spec. In this
case, I'm not sure if it is worth matching the Infiniband spec in this
one area. My feeling is that a driver circuit can be made to drive
up to either 1.0 volt or 1.6 volt relatively easily; but it would be
much more troublesome for a (XAUI) receiver to tolerate 1.6 volts
*needlessley*.
So, if the above reasoning is agreed to by others, I would propose that we
stay with 1.0 volt max. diff. amplitude that is in the current draft 1.0
(page 119, line 22).
-Robbie Shergill
National Semiconductor