Agenda:

Agenda:
1.        Training sequence/speed negotiation
http://www.t10.org/ftp/t10/document.05/05-397r3.pdf

The following ideas are for consideration. Please investigate and discuss on the 6/15 call. Reflector traffic is welcome and encouraged. Some concerns related to how the information is handled and whether it reaches beyond the PHY layer.

Idea floated in the WG meeting of just sending G1 traffic in the G3 window.  This should get through without needing training.

It would diverge from the normal window definition by:
* Start with training pattern? (Suggest leaving as idle time since speed will be determined later)
* Continue with ALIGN (0)/ALIGN (1) algorithm like today
* End by sending information about supported rates and features, not just sending ALIGN (1)s.  Include:
  - Additional rates supported (G3, G4, G5, etc.)
  - Whether the phy can receive SSC
  - Advice to the other transmitter to help it decide about tx amplitude, preemphasis, etc.
    * "Receiver device" characteristics (which it should know)
    * System interconnect characteristics (which it may know)

This would be the last trial window; there'd be no need for subsequent (G4, G5, etc.) windows following the current algorithm. The next window would be the final one, which would enable SSC if supported, start with a training sequence, perform whatever is needed for dword sync, etc. like has been discussed.  If lock is unsuccessful, the phys restart OOB.  If lock is repeatedly unsuccessful, turn off the fastest rate and try again.  (Same issues as today)

2.        Spread Spectrum Clocking
a. SSC options / trade-offs [Witt]
http://www.t10.org/ftp/t10/document.06/06-267r0.pdf

Compares up-, center- and down-spreading for SSC. Conclusion was that the short-term buffering impact of SSC is minimal, but long-term impact was not covered. Makes a possible case for center-spreading.

b. SAS-2 Spread-spectrum clocking by upspreading (06-263) [Elliott]
http://www.t10.org/ftp/t10/document.06/06-263r0.pdf

Present cases and issues with different SSC schemes. Supports up-spreading, but it looks like the center-spreading calculation may have not been done correctly regarding the buffer dword total. Kevin Witt will contact Rob about this.


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Webex information:
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Topic: SAS-2 PHY WG
Date: Thursday, June 15, 2006
Time: 10:00 am, Central Daylight Time (GMT -05:00, Chicago)
Meeting number: 826 515 680
Meeting password: 6gbpsSAS




Alvin Cox
Seagate Technology, LLC
Tel 405-350-7424
Cell 405-206-4809
E-Mail  alvin.cox@seagate.com