<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Hello,</div><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><br>I prefer option 1, the coupled words with pedestal, as it packs more info into the same space.</div></span></div></span></span>
</div><div><br class="webkit-block-placeholder"></div><div>First word</div><div><br></div><div>Do we need the 2bits for 'pulse'? From looking through the spec it seems that this is to label up to 4 pulses for which time data is to be sent. For the CDC this would always be 1, just 1 pulse, so could we dispense with it?</div><div><br></div><div>We would like to increase the bits available for time data from 10 to 11 bits, as an integer # of ns, that gives us 0-2047 ns. This allows some headroom for slower drift times. </div><div><br class="webkit-block-placeholder"></div><div><br></div><div>Second word</div><div><br></div><div>Pedestal. I would indeed like to include this but it is not necessary to have full range 0-4095 available in integer steps. We will set the pedestals to something low, ~55-60. How about outputting pedestal/8 to cover the subrange pedestal=0-504 as pedestal/8=0-63 in 6 bits. ? </div><div><br></div><div>Integral. OK.</div><div><br></div><div>Integral quality factor.</div><div>I would like to include a count of the number of overflowed samples contributing to the integral, this could count up to 63 samples (504ns) in the 6 bits freed up from the pedestal. </div><div><br></div><div>How does this sound?</div><div><br></div><div>Naomi.</div><div><br></div>
<br><div><div>On Jul 8, 2013, at 11:31 AM, David Lawrence wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite">
<meta content="text/html; charset=ISO-8859-1" http-equiv="Content-Type">
<div bgcolor="#FFFFFF" text="#000000">
<br>
Hi All,<br>
<br>
I spoke with Beni a little about this this morning since I am
currently<br>
working on the code that parses this for the online monitoring and<br>
the offline. I have not been involved in any other discussions, but
here<br>
are some thoughts based on what I've seen in the F250ADC formats<br>
and my discussion with Beni:<br>
<br>
1.) It is not possible to fit both the sum and the pulse time into a
single<br>
32-bit word. The word must have at least 12 bits of info to define
the<br>
data type and channel number leaving only 20 bits for payload. Hits<br>
in the F125 must therefore span two 32-bit words.<br>
<br>
2.) The FADC250 has a specification where the pulse time and pulse<br>
integrals appear as separate data types (i.e. they appear in
separate<br>
32-bit words). This allows the option of having a module output one<br>
of these but not the other. In practice, we will probably never want
to<br>
do this, but thee spec. allows it. To see the spec, look here, but<br>
be aware a few things in the headers have changed:<br>
<br>
<a class="moz-txt-link-freetext" href="https://halldweb1.jlab.org/wiki/images/d/db/FADC_Data_Format_V2.pdf">https://halldweb1.jlab.org/wiki/images/d/db/FADC_Data_Format_V2.pdf</a><br>
<br>
<br>
3.) For the FADC125, we could decide to couple the two words and<br>
eliminate redundant information such as the channel number,<br>
pulse number, and slot. This frees up enough bits to record a 12bit<br>
pedestal with every hit. I've drawn this out in the diagram below<br>
labeled Option1: to show how we could pack the bits in a format<br>
consistent with the spirit of the current F250 spec.<br>
<br>
4.) We could also follow almost exactly the format of the F250 spec.<br>
with the difference being that we need 7bits instead of 5 for the<br>
channel number in the F125. I've drawn this up as Option 2:<br>
below.<br>
<br>
5.) We could also have something completely different from either<br>
of these. In any case, we'll want the block header/trailer and<br>
event header words to follow the standard format for JLab modules<br>
whose current specification is here:<br>
<br>
<a class="moz-txt-link-freetext" href="https://halldweb1.jlab.org/wiki/images/5/58/JlabModuleDataFormat.pdf">https://halldweb1.jlab.org/wiki/images/5/58/JlabModuleDataFormat.pdf</a><br>
<br>
<br>
<span><fffahdgj.png></span><br>
<span><bgahdiae.png></span><br>
Regards,<br>
-David<br>
<br>
<div class="moz-cite-prefix">On 7/8/13 9:17 AM, Beni Zihlmann wrote:<br>
</div>
<blockquote cite="mid:51DABBF6.7070404@jlab.org" type="cite">
<pre wrap="">Hi All,
we have to come up with a list of specifications of the data we
want to have from the ADC. I would like to use this email to
initiate a discussion and put this topic on the agenda of the
next tracking meeting. By that time we should have a clear
understanding of what is needed so that the experts Cody
and Gerard can tell us what is feasible and what not.
cheers,
Beni
_______________________________________________
Halld-tracking-hw mailing list
<a class="moz-txt-link-abbreviated" href="mailto:Halld-tracking-hw@jlab.org">Halld-tracking-hw@jlab.org</a>
<a class="moz-txt-link-freetext" href="https://mailman.jlab.org/mailman/listinfo/halld-tracking-hw">https://mailman.jlab.org/mailman/listinfo/halld-tracking-hw</a>
</pre>
</blockquote>
<br>
</div>
_______________________________________________<br>Halld-tracking-hw mailing list<br><a href="mailto:Halld-tracking-hw@jlab.org">Halld-tracking-hw@jlab.org</a><br>https://mailman.jlab.org/mailman/listinfo/halld-tracking-hw</blockquote></div><br></body></html>