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RE: Clause 46 - Preamble

Hi Bob,

At 10:36 AM 02/16/2001 -0800, Grow, Bob wrote:

>There is nothing that a conforming implementation with the current PHY types
>will do to change the preamble length, but why add an unnecessary
>restriction to eliminate future options.  

I would think keeping an option to change the preamble size
by a PHY may lead to confusion and PHY/RS/MAC un-interoperable
implementations. It is not a restriction but an explicit specification
that would keep all the PHYs and RS implementations STANDARD.


>--Bob Grow
>-----Original Message-----
>From: Gareth Edwards [mailto:Gareth.Edwards@xxxxxxxxxx]
>Sent: Friday, February 16, 2001 7:56 AM
>Subject: Clause 46 - Preamble
>Afternoon all,
>Shimon raised a comment against D2.0 SC (#252) asking for the
>removal of the requirement that the preamble be a fixed length on
>receive; this was accepted in principle. However, I seem to remember in
>the discussion on this comment at Irvine that there was agreement that
>the Start control code and SFD couldn't appear in the same RXD column;
>there would be one or more clock edges between the Start code and SFD. 
>The new text (in D2.1 SC does not explicitly rule in or out
>the appearance of the SFD in the same column as the Start code; this is
>consistent with Shimon's original suggested remedy.
>Is this something that has slipped through the rewrite or has False
>Memory Syndrome struck again?
>/ /\/\ Gareth Edwards              mailto:gareth.edwards@xxxxxxxxxx
>\ \  / Design Engineer
>/ /  \ System Logic & Networking   Phone:   +44 131 666 2600 x234
>\_\/\/ Xilinx Scotland             Fax:     +44 131 666 0222