Reminder: SAS PHY WG call, 11/16, 10 am CST

Alvin.Cox at Alvin.Cox at
Tue Nov 14 07:51:04 PST 2006

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Weekly teleconferences scheduled for Thursdays at 10 am CST:
Toll Free Dial in Number: (866) 279-4742 
International Access/Caller Paid Dial In Number: (309) 229-0118 
Webex information:
Topic: SAS-2 PHY WG 
Date: Thursday 
Time: 10:00 am, Central Standard Time 
Meeting number: 826 515 680 
Meeting password: 6gbpsSAS
No call on 11/23 or 12/28.
Agenda (more than we can cover):
1. SAS-2 Modifications to the SAS Speed Negotiation 06-324r9 [Finch, 
(Should be a final review of the edited version.)
2. SAS-2 Electrical Specification Proposal 06-496 [Witt]
Page 13 has some interesting questions:
(I would like to concentrate on c and e this call.)
a) SSC Causes Measurement Issues:
• Tx Jitter Generation
• Rx Jitter Tolerance
b) Tx De-Emphasis Causes DJ Which Needs to be Removed Before Jitter
Generation Can Be Estimated?
c) Question: Do we Want to Support a Low-Swing Mode for Short / Clean
Channels? Just refer to use SATA 2 level for power saving if desired.
• 400..600mV
• No De-Emphasis
(My comment on this is that it is intended for IC-to-IC on a single PCB 
and does not use an existing defined compliance point. The specification 
allows deviation if the connection is not a compliance point, so my 
initial position is that we don't want to do this.)
d) Are We Going to Define a Rx Compliance Channel / Test? Yes we need to.
e) Are we going to support variable or fixed Tx De-Emphasis?
My comments:
• If fixed, how do we test?
• The table on page 6 has a -5dB to -7dB range for de-emphasis, but has a 
differential voltage range of 800 min / 1200 max. These seem to be in 
• Mike Jenkins has presented simulations that indicate a fixed de-emphasis 
may not be in the best interest.
What do we do? Maybe we allow de-emphasis to be used, but bounded by the 
allowed transmitter differential voltage values?
• Is the external cable application different than the internal 
requirements with regards to de-emphasis requirements?
3. 10-meter cable specification issues
Any updates?
4. EMI considerations for SAS-2
Keep in mind when developing spec.
5. Define a loss for the zero-length test load?
Alvin Cox
Seagate Technology, LLC
Tel 405-350-7424
Cell 405-206-4809
E-Mail	alvin.cox at

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