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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, Wassal]
http://www.t10.org/ftp/t10/document.06/06-324r9.pdf
(Should be a final review of the edited version.)

2. SAS-2 Electrical Specification Proposal 06-496 [Witt]
http://www.t10.org/ftp/t10/document.06/06-496r2.pdf

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 conflict.
• Mike Jenkins has presented simulations that indicate a fixed de-emphasis may not be in the best interest.
http://www.t10.org/ftp/t10/document.06/06-491r1.pdf
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
http://www.t10.org/ftp/t10/document.06/06-499r0.pdf
Any updates?

4. EMI considerations for SAS-2
http://www.t10.org/ftp/t10/document.06/06-483r0.pdf
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@seagate.com