Confusion in OOB sequence

Shah, Amit M amit.m.shah at intel.com
Fri Jun 4 09:51:19 PDT 2004


* From the T10 Reflector (t10 at t10.org), posted by:
* "Shah, Amit M" <amit.m.shah at intel.com>
*
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My answers are embedded.

Amit Shah

Intel Corporation

=20

-----Original Message-----
From: owner-t10 at t10.org [mailto:owner-t10 at t10.org] On Behalf Of Rajesh =
K
N
Sent: Friday, June 04, 2004 4:20 AM
To: t10 at t10.org
Cc: knrajesh at sasken.com
Subject: Confusion in OOB sequence

=20

Hi,

=20

We have a confusion on SAS OOB sequence. =20

=20

1. Our understanding of OOB sequnece from the specification is,=20

   during ALIGN burst period, ALIGN0 primitives should be=20

   transmitted/detected.

  =20

   a. Specification says that ALIGNs are used for the generation

      of the ALIGN burst envelop?

     =20

      Please clarify the above point.

=20

=20

ANS : ALIGN0 needs to be transmitted by the transmitter.

=20

         =20

2.  How the ALIGN bursts are detected? Are they detected as any=20

    transitions or as a proper ALIGN0 primitives?.

=20

=20

Ans : The burst is detected as any transition. Remember the receiver
would not have achieved DW SYNC during an OOB sequence. So there is no
way to decode the incoming data. Also the OOB sequence happens at a
different voltage level compared to normal data transmission. So the
receiver would only detect the incoming signal as DC IDLE or "any
transition / burst". The link layer would not receive any 10b data to
get decoded as ALIGN0 reception.

   =20

3.  How to differentiate between spurious burst/idle time pairs=20

    from proper burst/idle time pairs if any transitions are

    permitted in the ALIGN bursts. (Assumption here is that, in=20

    case of spurious burst/idle time pairs, idle time is matching the

    COMINIT idle time)

=20

Ans : The OOB detection is based on detecting "4" number of correct =
IDLE
time's between burst (which could be of any duration, no specific
constraint is mentioned in the specs). Idle time has been specified =
with
a min. and max. time constraint for each OOB signal. Detection of "4"
correct / valid IDLE time can mark detection of an OOB signal. So the
transmitter of the OOB signal makes sure that when it is in calibration
state, it will not transmit calibration pulses at a duration which =
could
decoded as a correct IDLE time for specified OOB signals. Also if there
is any noise, what are the chances that the noise is such that it will
repeat "4" times after a valid IDLE time as defined for a particular =
OOB
signals.

        =20

Please let us know.

=20

Thanks and Regards

K.N.Rajesh

Hardware Engineer

Zero-In - Semicon BU

Sasken Communication Technologies Limited

139/25, Ring Road, Domlur

Bangalore - 560071 India

Email: knrajesh at sasken.com=20

Tel: + 91 80 5355501 Extn: 8198=20

Fax: + 91 80 5351133

URL: www.sasken.com

=20


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<p class=3DMsoPlainText><font size=3D2 face=3D"Courier New"><span =
style=3D'font-size:
10.0pt'>My answers are embedded.<o:p></o:p></span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3D"Courier New"><span =
style=3D'font-size:
10.0pt'>Amit Shah<o:p></o:p></span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3D"Courier New"><span =
style=3D'font-size:
10.0pt'>Intel Corporation<o:p></o:p></span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3D"Courier New"><span =
style=3D'font-size:
10.0pt'><o:p>&nbsp;</o:p></span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3D"Courier New"><span =
style=3D'font-size:
10.0pt'>-----Original Message-----<br>
From: owner-<st1:PersonName w:st=3D"on">t10 at t10.org</st1:PersonName>
[mailto:owner-<st1:PersonName w:st=3D"on">t10 at t10.org</st1:PersonName>] =
On Behalf
Of Rajesh K N<br>
Sent: Friday, June 04, 2004 4:20 AM<br>
To: <st1:PersonName w:st=3D"on">t10 at t10.org</st1:PersonName><br>
Cc: knrajesh at sasken.com<br>
Subject: Confusion in OOB sequence</span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3D"Courier New"><span =
style=3D'font-size:
10.0pt'><o:p>&nbsp;</o:p></span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3D"Courier New"><span =
style=3D'font-size:
10.0pt'>Hi,<o:p></o:p></span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3D"Courier New"><span =
style=3D'font-size:
10.0pt'><o:p>&nbsp;</o:p></span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3D"Courier New"><span =
style=3D'font-size:
10.0pt'>We have a confusion on SAS OOB sequence.&nbsp; =
<o:p></o:p></span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3D"Courier New"><span =
style=3D'font-size:
10.0pt'><o:p>&nbsp;</o:p></span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3D"Courier New"><span =
style=3D'font-size:
10.0pt'>1. Our understanding of OOB sequnece from the specification is, =
<o:p></o:p></span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3D"Courier New"><span =
style=3D'font-size:
10.0pt'>&nbsp;&nbsp; during ALIGN burst period, ALIGN0 primitives =
should be <o:p></o:p></span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3D"Courier New"><span =
style=3D'font-size:
10.0pt'>&nbsp;&nbsp; transmitted/detected.<o:p></o:p></span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3D"Courier New"><span =
style=3D'font-size:
10.0pt'>&nbsp;&nbsp; <o:p></o:p></span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3D"Courier New"><span =
style=3D'font-size:
10.0pt'>&nbsp;&nbsp; a. Specification says that ALIGNs are used for the
generation<o:p></o:p></span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3D"Courier New"><span =
style=3D'font-size:
10.0pt'>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; of the ALIGN burst =
envelop?<o:p></o:p></span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3D"Courier New"><span =
style=3D'font-size:
10.0pt'>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <o:p></o:p></span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3D"Courier New"><span =
style=3D'font-size:
10.0pt'>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Please clarify the above =
point.<o:p></o:p></span></font></p>

<p class=3DMsoPlainText><b><font size=3D2 color=3Dblack face=3D"Courier =
New"><span
style=3D'font-size:10.0pt;color:black;font-weight:bold'><o:p>&nbsp;</o:p=
></span></font></b></p>

<p class=3DMsoPlainText><b><font size=3D2 color=3Dblack face=3D"Courier =
New"><span
style=3D'font-size:10.0pt;color:black;font-weight:bold'><o:p>&nbsp;</o:p=
></span></font></b></p>

<p class=3DMsoPlainText><b><font size=3D2 color=3Dblack face=3D"Courier =
New"><span
style=3D'font-size:10.0pt;color:black;font-weight:bold'>ANS =
:</span></font></b><font
color=3Dblack><span style=3D'color:black'> ALIGN0 needs to be =
transmitted by the
transmitter.<o:p></o:p></span></font></p>

<p class=3DMsoPlainText><font size=3D2 color=3Dblack face=3D"Courier =
New"><span
style=3D'font-size:10.0pt;color:black'><o:p>&nbsp;</o:p></span></font></=
p>

<p class=3DMsoPlainText><font size=3D2 face=3D"Courier New"><span =
style=3D'font-size:
10.0pt'>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; =
<o:p></o:p></span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3D"Courier New"><span =
style=3D'font-size:
10.0pt'>2.&nbsp; How the ALIGN bursts are detected? Are they detected =
as any <o:p></o:p></span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3D"Courier New"><span =
style=3D'font-size:
10.0pt'>&nbsp;&nbsp;&nbsp; transitions or as a proper ALIGN0 =
primitives?.<o:p></o:p></span></font></p>

<p class=3DMsoPlainText><font size=3D2 color=3Dblack face=3D"Courier =
New"><span
style=3D'font-size:10.0pt;color:black'><o:p>&nbsp;</o:p></span></font></=
p>

<p class=3DMsoPlainText><font size=3D2 color=3Dblack face=3D"Courier =
New"><span
style=3D'font-size:10.0pt;color:black'><o:p>&nbsp;</o:p></span></font></=
p>

<p class=3DMsoPlainText><b><font size=3D2 color=3Dblack face=3D"Courier =
New"><span
style=3D'font-size:10.0pt;color:black;font-weight:bold'>Ans =
:</span></font></b><font
color=3Dblack><span style=3D'color:black'> The burst is detected as any =
transition.
Remember the receiver would not have achieved DW SYNC during an OOB =
sequence.
So there is no way to decode the incoming data. Also the OOB sequence =
happens
at a different voltage level compared to normal data transmission. So =
the
receiver would only detect the incoming signal as DC IDLE or "any
transition / burst". The link layer would not receive any 10b data =
to get
decoded as ALIGN0 reception.<o:p></o:p></span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3D"Courier New"><span =
style=3D'font-size:
10.0pt'>&nbsp;&nbsp;&nbsp; <o:p></o:p></span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3D"Courier New"><span =
style=3D'font-size:
10.0pt'>3.&nbsp; How to differentiate between spurious burst/idle time =
pairs <o:p></o:p></span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3D"Courier New"><span =
style=3D'font-size:
10.0pt'>&nbsp;&nbsp;&nbsp; from proper burst/idle time pairs if any =
transitions
are<o:p></o:p></span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3D"Courier New"><span =
style=3D'font-size:
10.0pt'>&nbsp;&nbsp;&nbsp; permitted in the ALIGN bursts. (Assumption =
here is
that, in <o:p></o:p></span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3D"Courier New"><span =
style=3D'font-size:
10.0pt'>&nbsp;&nbsp;&nbsp; case of spurious burst/idle time pairs, idle =
time is
matching the<o:p></o:p></span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3D"Courier New"><span =
style=3D'font-size:
10.0pt'>&nbsp;&nbsp;&nbsp; COMINIT idle =
time)<o:p></o:p></span></font></p>

<p class=3DMsoPlainText><font size=3D2 color=3Dblack face=3D"Courier =
New"><span
style=3D'font-size:10.0pt;color:black'><o:p>&nbsp;</o:p></span></font></=
p>

<p class=3DMsoPlainText><b><font size=3D2 color=3Dblack face=3D"Courier =
New"><span
style=3D'font-size:10.0pt;color:black;font-weight:bold'>Ans =
:</span></font></b><font
color=3Dblack><span style=3D'color:black'> The OOB detection is based =
on detecting <b><span
style=3D'font-weight:bold'>"4"</span></b> number of correct =
IDLE time's
between burst (which could be of any duration, no specific constraint =
is
mentioned in the specs). Idle time has been specified with a min. and =
max. time
constraint for each OOB signal. Detection of <b><span =
style=3D'font-weight:bold'>"4"
correct / valid IDLE time</span></b> can mark detection of an OOB =
signal. So the
transmitter of the OOB signal makes sure that when it is in calibration =
state,
it will not transmit calibration pulses at a duration which could =
decoded as a
correct IDLE time for specified OOB signals. Also if there is any =
noise, what
are the chances that the noise is such that it will repeat =
"4" times after
a valid IDLE time as defined for a particular OOB =
signals.<o:p></o:p></span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3D"Courier New"><span =
style=3D'font-size:
10.0pt'>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; =
<o:p></o:p></span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3D"Courier New"><span =
style=3D'font-size:
10.0pt'>Please let us know.<o:p></o:p></span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3D"Courier New"><span =
style=3D'font-size:
10.0pt'><o:p>&nbsp;</o:p></span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3D"Courier New"><span =
style=3D'font-size:
10.0pt'>Thanks and Regards<o:p></o:p></span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3D"Courier New"><span =
style=3D'font-size:
10.0pt'>K.N.Rajesh<o:p></o:p></span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3D"Courier New"><span =
style=3D'font-size:
10.0pt'>Hardware Engineer<o:p></o:p></span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3D"Courier New"><span =
style=3D'font-size:
10.0pt'>Zero-In - Semicon BU<o:p></o:p></span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3D"Courier New"><span =
style=3D'font-size:
10.0pt'>Sasken Communication Technologies =
Limited<o:p></o:p></span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3D"Courier New"><span =
style=3D'font-size:
10.0pt'>139/25, Ring Road, Domlur<o:p></o:p></span></font></p>

<p class=3DMsoPlainText><st1:City w:st=3D"on"><font size=3D2 =
face=3D"Courier New"><span
 style=3D'font-size:10.0pt'>Bangalore</span></font></st1:City> - 560071 =
<st1:country-region
w:st=3D"on"><st1:place =
w:st=3D"on">India</st1:place></st1:country-region><o:p></o:p></p>

<p class=3DMsoPlainText><font size=3D2 face=3D"Courier New"><span =
style=3D'font-size:
10.0pt'>Email: knrajesh at sasken.com <o:p></o:p></span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3D"Courier New"><span =
style=3D'font-size:
10.0pt'>Tel: + 91 80 5355501 Extn: 8198 <o:p></o:p></span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3D"Courier New"><span =
style=3D'font-size:
10.0pt'>Fax: + 91 80 5351133<o:p></o:p></span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3D"Courier New"><span =
style=3D'font-size:
10.0pt'>URL: www.sasken.com<o:p></o:p></span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3D"Courier New"><span =
style=3D'font-size:
10.0pt'><o:p>&nbsp;</o:p></span></font></p>

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