[T10] SAS 12 Spec question related to HSS and connectors

Harvey Newman harvey.newman at avagotech.com
Mon Oct 19 09:44:59 PDT 2015


Hi Kevin,

In SAS-3 we have specified the compliance points at the die pads.  Since
this compliance point is not typically able to be probed directly the
specification SAS3r06 provides tools and limits based on measurements taken
at the connector.  Please review Annex D starting with Figure D.1.  We do
not directly state the trace length between the connector and the
compliance point.  We allow implementations to balance the loss of the
traces and the capabilities of the SerDes.

We do provide for purpose of testing a model of the loss between the
connector and the compliance point.  For Tx the separable usage model use
Table D.2. For Tx the non-separable usage model use Table D.3. For Rx use
Table D.5.

These models are used to set up the test conditions. As long as the
combined SerDes and interconnect up to the measurement point combined meet
the spec the actual electrical performance of the traces is not specified.

Hope this is helpful.

Regards,
Harvey Newman
Avago Technologies

On Tue, Oct 13, 2015 at 10:52 AM, Kevin D Butt <kdbutt at us.ibm.com> wrote:

> I am looking through the SAS spec and trying to find if there is anything
> related to the connection between the HSS and the connector. Is there
> anything in SAS-3 or SAS-4 that specifies acceptable trace lengths, signal
> characteristics, etc. for on card traces between an HSS and a connector?
>
> Thanks,
>
> Kevin D. Butt
> SCSI Architect, Tape Firmware, CAMSS
> T10 Standards
> MS 6TYA, 9000 S. Rita Rd., Tucson, AZ 85744
> Tel: 520-799-5280
> Fax: 520-799-2723 (T/L:321)
> Email address: kdbutt at us.ibm.com
> http://www-03.ibm.com/servers/storage/
>
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-- 
Harvey Newman
Avago Technologies
(408) 433-4028
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