Question about SAS 12G coefficient's adjustment rules

Harvey Newman harvey.newman at avagotech.com
Fri Mar 6 14:42:42 PST 2015


Formatted message: <a href="http://www.t10.org/cgi-bin/ac.pl?t=r&f=r1503061_f.htm">HTML-formatted message</a>

Hi Pengfei,
Your equations are not using the designations we have in our spec but the
point is the coeffients are negative, a decrement causes the value to go
more negative causing a larger amount of equalization.
c1-0.1=-0.3 is the correct answer.
Regards,
Harvey Newman
Avago Technologies
On Fri, Mar 6, 2015 at 12:00 AM, Yupengfei (B) <yu.yupengfei at hisilicon.com>
wrote:
>  Hi Harvey
>
>
>
> OK, thanks, and I have one more question.
>
>
>
> As far as I know, c1/ c2/ c3 is equalization coefficient of TX direction
> , used in 12G TX_Training and both c1 and c3 are zero or negative:
>
>
>
> V_outn=(v_inn+1*c3)+ (v_inn*c2)+ (v_inn-1*c1)
>
>
>
> So I want to ask, when we receive a decrement request of c3 or c1 in TTIU
> during 12G TX_Training,  we should decrease its absolute value or
> increase its absolute value?
>
>
>
> For example, now our coefficient is :
>
> c1=-0.2 ;    c2=0.7  ;     c3=-0.1 ;
>
>
>
> when we receive a decrement request of c1 , what’s the value of c1 now?
>
> (we assume the decrement is 0.1 in one request.)
>
> It’s
>
> c1-0.1=-0.3;
>
> or
>
>      -(|c1|-0.1)=-0.1;
>
>
>
> Which is correct?
>
>
>
>
>
> Best Regards,
>
> Pengfei Yu
>
>
>
>
>
>
>
>
>
> Hi Pengfei,
>
>
>
> SAS 12G Tx training does not have any such requirement. The transmitter
> coefficients are free to be adjusted by the receiver in any way it wishes.
> This includes an over all decrease in amplitude if it so desires.
>
>
>
> Regards,
> Harvey Newman
>
> Avago Technologies
>
>
>
> On Wed, Mar 4, 2015 at 10:57 PM, Yupengfei (B) <yu.yupengfei at hisilicon.com>
> wrote:
>
> Hi all,
>
>
>
> I would like to know, during the process of SAS 12G TX_TRAINING, is there
> any rules like PCI-E:
>
>
>
> “The sum of C1, C2, and C3 should keep a fixed value (|C-1|+|C+1|+C0 =
> FS)”.
>
>
>
> If there is any, please specify the source in the agreement.
>
>
>
> Thank you!
>
>
>
>
>
> Best regards,
>
> Pengfei Yu
>
>
>
>
>
> --
>
> Harvey Newman
>
> Avago Technologies
>
> (408) 433-4028
>
-- 
Harvey Newman
Avago Technologies
(408) 433-4028



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