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RE: Clause 48: enable_cdet

Enable_cdet only enables and disables detection of unaligned commas. When
enable_cdet is true, then unaligned commas are detected and detection of an
unaligned comma adjusts the code group boundary to match the position of the
comma. When enable_cdet is false, then commas will only be detected when
they are aligned to the current code group boundaries and a misaligned comma
will just be a code violation.
The state machine functions correctly. The variable description could stand
some rewording to make it more clear that it is the detection of unaligned
commas which is being enabled.
-----Original Message-----
From: Taborek, Rich [mailto:rich.taborek@xxxxxxxxx]
Sent: Monday, March 26, 2001 6:17 PM
To: HSSG (E-mail)
Subject: RE: Clause 48: enable_cdet 

Enable_cdet is only required to be true to exit the LOSS_OF_SYNC state. It's
state is not relevant to progress in any other state of the Synchronization
state diagram. 
Whenever enable_cdet=TRUE code-group alignment takes occurs. It is
undesirable to detect commas aligned to a different boundary once the first
comma is detected following entry into the LOSS_OF_SYNC state (and the
setting of enable_cdet<=TRUE). Therefore, it is appropriate to disable
further code-group alignment upon entry to state COMMA_DETECT_1. 


Best Regards,
Richard Taborek Sr.     XAUI Sherpa     Intel Corporation   
Santa Clara Design Center     Network Components Division
408-496-3423     Fax: 408-486-9859     Cell: 408-832-3957
3101 Jay Street, Suite 110          Santa Clara, CA 95054
mailto:rich.taborek@xxxxxxxxx <mailto:rich.taborek@xxxxxxxxx> <>  

-----Original Message-----
From: Rogers, Shawn [mailto:s-rogers@xxxxxx]
Sent: Monday, March 26, 2001 2:10 PM
To: 'rich.taborek@xxxxxxxxx'
Cc: '802.3ae'
Subject: Clause 48: enable_cdet 

Rich, I'd like some clarification on this before deciding on whether to
enter a comment on D2.3.  

In Figure 48.8, 
   In the LOSS_OF_SYNC state, enable_cdet = true. 
   Exiting LOSS_OF_SYNC state is dependent on valid signal detect and
detecting a comma.  
   In the COMMA_DETECT_1 state, enable_cdet = false. 
   Exiting COMMA_DETECT_1 to go to COMMA_DETECT_2 is dependent on a valid

How do you get to COMMA_DETECT_2 when comma detect is turned off?   

Also, on a more generic note, why turn off comma detect so early in the sync
state machine? 


Shawn Rogers,   PMP 
Serial Gigabit Products Dev. Mgr. 
Texas Instruments/ 12500 TI Boulevard 
M/S 8732/ Dallas, Texas 75243 
Tel: 214-480-2678, Fax: 214 761-6954 Pager: 972-597-1803