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Thank you for the clarification. In that case, it seem there is
nothing else we can do on our end other than hope that Linux folks
improve on their I2C implementation.<br>
<br>
Best,<br>
<br>
Ico<br>
<br>
<div class="moz-cite-prefix">On 7/10/2015 7:51 AM, Luis G Angel
wrote:<br>
</div>
<blockquote
cite="mid:C123B37F-D23F-4A21-8AF5-CC229166A47C@gmail.com"
type="cite">
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Yes it work with 16 channel running at the same time (via opening
2 devices, 8 channels each). The problem is the actual SPI linux
library only instance 2 of the 3 SPI devices available in the PI’s
hardware, in order to that we only can use 2 SPI devices. If you
want more SPI devices there are two ways: you write your own SPI
library and use any other GPIO pins as slave select or modify the
actual SPI linux library (I thinks it is in the kernel, but don’t
know).
<div class=""><br class="">
</div>
<div class="">Luis G<br class="">
<div class=""><br class="">
<div>
<blockquote type="cite" class="">
<div class="">El 09/07/2015, a las 4:49 a.m., Ivica Ico
Bukvic <<a moz-do-not-send="true"
href="mailto:ico@vt.edu" class="">ico@vt.edu</a>>
escribió:</div>
<br class="Apple-interchange-newline">
<div class="">
<meta content="text/html; charset=utf-8"
http-equiv="Content-Type" class="">
<div bgcolor="#FFFFFF" text="#000000" class=""> Thank
you for the follow-up, Luis. If I understand you
correctly, does the disis_spi therefore work for at
least 16 channels (via opening 2 devices, 8 channels
each) or it does not work at all?<br class="">
<br class="">
disis_spi has its own implementation of accessing
spidevs, and (AFAIR) it should not have any
limitations as far as how many devices can be opened
at once (obviously, you will need one instance per
device). Perhaps the limitation you speak of is
hardware-specific?<br class="">
<br class="">
Best,<br class="">
<br class="">
Ico<br class="">
<br class="">
<div class="moz-cite-prefix">On 7/9/2015 3:42 AM, Luis
Gerardo Angel S. wrote:<br class="">
</div>
<blockquote
cite="mid:1436406174.2201.0@smtp.gmail.com"
type="cite" class=""> Hi
<div class=""><br class="">
</div>
<div class="">I probe the program, you were right
you can specify the device and it just
work(attached example).</div>
<div class="">The controller have 3 chip selectors
for the SPI (three slaves), although you can only
connect two devices according to this: <a
moz-do-not-send="true"
href="http://elinux.org/RPi_SPI" class="">http://elinux.org/RPi_SPI</a>.
You can confirm it with "ls /dev" command, there
are only two SPI devices.</div>
<div class="">I read in some forum (can't remember
which ones) this is due to how the library was
written leaving out the third chip selector.</div>
<div class=""><br class="">
</div>
<div class=""> At the present time the only way to
connect more SPI devices is: write your own SPI
library (maybe with wiringPi) and use the GPIO's
general purpose(pardon the redundancy) pins like
selectors. It would be nice we can use the third
selector with another "/dev/spidev0.2" in that way
the external does not have to be modified and 24
analog inputs would be very good.</div>
<div class=""><br class="">
</div>
<div class="">Luis G</div>
<div class=""><br class="">
On mié, jul 8, 2015 at 3:49 , Ivica Ico Bukvic <a
moz-do-not-send="true"
class="moz-txt-link-rfc2396E"
href="mailto:ico@vt.edu"><ico@vt.edu></a>
wrote:<br class="">
<blockquote type="cite" class="">
<div class="plaintext" style="white-space:
pre-wrap;">Hi Luis, I am not 100% sure but if
I recall correctly, you can specify which
device you wish to open, so as long as each
device is assigned a different /dev node, this
should work just fine. I would appreciate it
if you would please report your results and
let us know. Alternately, there are larger D/A
converters that provide you with more inputs,
but will also require a customized version of
disis_spi. Hope this helps! Best, Ico On
7/7/2015 11:41 PM, Luis G Angel wrote:
<blockquote class="">Hi list I want to use two
MCP3008 in order to connect 16 analog inputs
to the Pi2, so my question is if the
[disis_spi] is capable to manage 2 slaves.
If it is, how it should be the patch to
manage that. Thanks for any idea Luis G
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href="http://disis.music.vt.edu/listinfo/l2ork-dev"
class="">http://disis.music.vt.edu/listinfo/l2ork-dev</a>
</blockquote>
<div class="">-- </div>
Ivica Ico Bukvic, D.M.A. Associate Professor
Computer Music ICAT Senior Fellow Director --
DISIS, L2Ork Virginia Tech School of
Performing Arts – 0141 Blacksburg, VA 24061
(540) 231-6139 <a moz-do-not-send="true"
class="moz-txt-link-abbreviated"
href="mailto:ico@vt.edu">ico@vt.edu</a> <a
moz-do-not-send="true"
href="http://www.performingarts.vt.edu/"
class="">www.performingarts.vt.edu</a> <a
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href="http://disis.icat.vt.edu" class="">disis.icat.vt.edu</a>
<a moz-do-not-send="true"
href="http://l2ork.icat.vt.edu" class="">l2ork.icat.vt.edu</a>
_______________________________________________
L2Ork-dev mailing list <a
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href="mailto:L2Ork-dev@disis.music.vt.edu">L2Ork-dev@disis.music.vt.edu</a>
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href="http://disis.music.vt.edu/listinfo/l2ork-dev"
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</blockquote>
</div>
</blockquote>
<br class="">
<pre class="moz-signature" cols="72">--
Ivica Ico Bukvic, D.M.A.
Associate Professor
Computer Music
ICAT Senior Fellow
Director -- DISIS, L2Ork
Virginia Tech
School of Performing Arts – 0141
Blacksburg, VA 24061
(540) 231-6139
<a moz-do-not-send="true" class="moz-txt-link-abbreviated" href="mailto:ico@vt.edu">ico@vt.edu</a>
<a moz-do-not-send="true" class="moz-txt-link-abbreviated" href="http://www.performingarts.vt.edu/">www.performingarts.vt.edu</a>
<a moz-do-not-send="true" href="http://disis.icat.vt.edu" class="">disis.icat.vt.edu</a>
<a moz-do-not-send="true" href="http://l2ork.icat.vt.edu" class="">l2ork.icat.vt.edu</a></pre>
</div>
</div>
</blockquote>
</div>
<br class="">
</div>
</div>
</blockquote>
<br>
<pre class="moz-signature" cols="72">--
Ivica Ico Bukvic, D.M.A.
Associate Professor
Computer Music
ICAT Senior Fellow
Director -- DISIS, L2Ork
Virginia Tech
School of Performing Arts – 0141
Blacksburg, VA 24061
(540) 231-6139
<a class="moz-txt-link-abbreviated" href="mailto:ico@vt.edu">ico@vt.edu</a>
<a class="moz-txt-link-abbreviated" href="http://www.performingarts.vt.edu">www.performingarts.vt.edu</a>
disis.icat.vt.edu
l2ork.icat.vt.edu</pre>
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