SAS - primitives inside frames

John Lohmeyer lohmeyer at t10.org
Wed Jun 26 10:11:41 PDT 2002


* From the T10 Reflector (t10 at t10.org), posted by:
* John Lohmeyer <lohmeyer at t10.org>
*
Sriram,

The SAS Protocol WG reviewed your email today. From the minutes:

>The group reviewed an email from Sriram Srinivasan dated 6/24/2002 
>regarding SAS primitives inside frames. Sriram questioned whether 
>primitives are permitted between the CRC and the EOF. The group agreed 
>that primitives are permitted here. It appears that the definition of 
>dword needs some clarification. In some places we mean 4 contiguous 
>characters. Other places we mean a dword that starts with Dxx.y (data 
>character). The group agreed to add a definition:
>
>data dword: A dword that starts with a Dxx.y (data character).
>
>The description of the CRC location was changed to: "The last data dword 
>after the SOF prior to the EOF always contains a CRC."

Primitives can appear anywhere in a frame including just after the SOF and 
between the CRC and the EOF. Rob is working on clarifying places that may 
imply otherwise. If you find any more places that need clarification in rev 
00d (to be posted soon), please let Rob know.

Regards,
John


At 6/24/2002 11:17 AM, Sriram Srinivasan wrote:
>* From the T10 Reflector (t10 at t10.org), posted by:
>* Sriram Srinivasan <srirams at lsil.com>
>*
>
>   In sas-r00c.pdf, clause "7.14.3 SSP frame transmission" states:
>
>"The dword prior to the EOF always contains a CRC. The link layer shall
>check that the frame length is at least 24 bytes and that the CRC is valid."
>
>   Was this intentional?  The last time I posted a question on the reflector
>the reply was that primitives are allowed anywhere in the frame and the CRC
>is the last non-primitive dword before the EOF primitive.  Is this still
>true?  Or can the receiving device ALWAYS count on the CRC being THE dword
>before the EOF?
>
>   Also what I missed was that caluse "7.14.7.7.1 SSP_T1:Transmit state
>description" states:
>
>   "... shall transmit an SOF in THE dword before THE FIRST DWORD of the
>frame and an EOF in FIRST DWORD after the last dword of the frame"
>
>   Which also precludes primitives right after an SOF?  Correct?  If this
>were not true the wording should replace "... SOF in the dword before ..."
>with "... SOF in a dword before ..."
>
>   thank you,
>   \Sriram\
>
>----------------------------------------------------------------------
>         "FORGET NOT THAT THE EARTH DELIGHTS TO FEEL YOUR BARE FEET,
>                AND THE WINDS LONG TO PLAY WITH YOUR HAIR"
>                                           -Khalil Gibran
>
>  Sriram Srinivasan                       Sriram.Srinivasan at lsil.com
>  ASIC Design Engineer, LSI Logic,
>  2001 Danfield Ct.,                             Phone: 970-206-5847
>  Fort Collins, CO 80525                         FAX  : 970-206-5244
>----------------------------------------------------------------------
>
>*
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--
John Lohmeyer                  Email: lohmeyer at t10.org
LSI Logic Corp.                Voice: +1-719-533-7560
4420 ArrowsWest Dr.              Fax: +1-719-533-7183
Colo Spgs, CO 80907

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