<html><body><div style="color:#000; background-color:#fff; font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:12px"><div id="yiv7825439105"><div id="yui_3_16_0_1_1443721524175_25382"><div style="color:#000;background-color:#fff;font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:12px;" id="yui_3_16_0_1_1443721524175_25381"><div dir="ltr" id="yiv7825439105yui_3_16_0_1_1443721524175_19619"><span id="yiv7825439105yui_3_16_0_1_1443721524175_19768">Other contraints include c</span>ost and space. Obviously if we could just build an ip network, none of this discussion would be interesting. It would be rather dull. Just buy the parts and be done with it. The suggestion for the communication sub-system is really just a recycled idea of a switch/router. Multiple serial comms and a processor. The interesting part is doing it with low cost and making it fit the needs of your project. I am looking into the ATTINY 841 (~$0.089) as a low cost UART to i2c interface for a comm sub system. It is not nearly as fancy as Chip's chip, but I am also not looking to go long distances. The program space is kind of small too.</div><div dir="ltr" id="yiv7825439105yui_3_16_0_1_1443721524175_19619"><br></div><div dir="ltr" id="yiv7825439105yui_3_16_0_1_1443721524175_19619">John Vaughters</div> <br clear="none"><div class="yiv7825439105qtdSeparateBR" id="yui_3_16_0_1_1443721524175_25380"><br clear="none"><br clear="none"></div></div></div></div><div class=".yiv7825439105yahoo_quoted"> <div style="font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:12px;"> <div style="font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:16px;"> <div class="qtdSeparateBR"><br><br></div><div class="yiv7825439105yqt6448585207" id="yiv7825439105yqt53451"><div dir="ltr"> <font size="2" face="Arial"> On Thursday, October 1, 2015 3:14 PM, Charles McClelland via TriEmbed <triembed@triembed.org> wrote:<br clear="none"> </font> </div> <br clear="none"><br clear="none"> <div class="yiv7825439105y_msg_container"><div id="yiv7825439105"><div>Fred, <div class="yiv7825439105"><br clear="none" class="yiv7825439105"></div><div class="yiv7825439105">Yes, but even more interesting is the constraint - it has to run for days or weeks on a battery. </div><div class="yiv7825439105"><br clear="none" class="yiv7825439105"></div><div class="yiv7825439105">Chip</div><div class="yiv7825439105yqt9102336418" id="yiv7825439105yqt96698"><div class="yiv7825439105"><br clear="none" class="yiv7825439105"><div><blockquote class="yiv7825439105" type="cite"><div class="yiv7825439105">On Oct 1, 2015, at 2:49 PM, Fred Ebeling <<a rel="nofollow" shape="rect" class="yiv7825439105" ymailto="mailto:FEbeling@ECPDesigns.com" target="_blank" href="mailto:FEbeling@ECPDesigns.com">FEbeling@ECPDesigns.com</a>> wrote:</div><br clear="none" class="yiv7825439105Apple-interchange-newline"><div class="yiv7825439105">
</div></blockquote></div></div></div></div><div class="yiv7825439105yqt9102336418" id="yiv7825439105yqt55280"><div><div class="yiv7825439105" dir="ltr" style="WORD-WRAP:break-word;">
<div class="yiv7825439105" dir="ltr">
<div class="yiv7825439105" style="font-size:12pt;font-family:Calibri;">
<div class="yiv7825439105">This is an interesting problem, how do you create a network that has</div>
<div class="yiv7825439105">multiple nodes that run all over the place and still maintain some</div>
<div class="yiv7825439105">type of interaction. How about the “WEB”.</div>
<div class="yiv7825439105"> </div>
<div class="yiv7825439105">Fred</div>
<div class="yiv7825439105" style="font-size:small;text-decoration:none;font-family:Calibri;font-weight:normal;font-style:normal;display:inline;">
<div class="yiv7825439105" style="FONT:10pt tahoma;">
<div class="yiv7825439105"> </div>
<div class="yiv7825439105" style="BACKGROUND:#f5f5f5;">
<div class="yiv7825439105" style=""><b class="yiv7825439105">From:</b> <a rel="nofollow" shape="rect" class="yiv7825439105" title="triembed@triembed.org" ymailto="mailto:triembed@triembed.org" target="_blank" href="mailto:triembed@triembed.org">Charles McClelland via TriEmbed</a> </div>
<div class="yiv7825439105"><b class="yiv7825439105">Sent:</b> Thursday, October 01, 2015 2:07 PM</div>
<div class="yiv7825439105"><b class="yiv7825439105">To:</b> <a rel="nofollow" shape="rect" class="yiv7825439105" title="triembed@triembed.org" ymailto="mailto:triembed@triembed.org" target="_blank" href="mailto:triembed@triembed.org">triembed@triembed.org</a> </div>
<div class="yiv7825439105"><b class="yiv7825439105">Subject:</b> [TriEmbed] I2C range extension</div></div></div>
<div class="yiv7825439105"> </div></div>
<div class="yiv7825439105" style="font-size:small;text-decoration:none;font-family:Calibri;font-weight:normal;font-style:normal;display:inline;">Fred,
<div class="yiv7825439105"> </div>
<div class="yiv7825439105">Thanks for the history and tip on RS-485. As with all things
engineering there are tradeoffs. Do you think I captured them correctly
below:</div>
<div class="yiv7825439105"> </div>
<div class="yiv7825439105">For an i2c sensor, communicating with a micro controller, using:</div>
<div class="yiv7825439105"> </div>
<div class="yiv7825439105">An i2c extender / redriver:</div>
<div class="yiv7825439105"><span class="yiv7825439105Apple-tab-span" style="WHITE-SPACE:pre;"></span>- Such as the<a rel="nofollow" shape="rect" class="yiv7825439105" target="_blank" href="http://www.ti.com/lit/ds/symlink/p82b715.pdf">TI P82B715DR</a></div>
<div class="yiv7825439105"><span class="yiv7825439105Apple-tab-span" style="WHITE-SPACE:pre;"></span>- Can go up to
5m at 5V but 3.3V operation works - just at reduced range</div>
<div class="yiv7825439105"><span class="yiv7825439105Apple-tab-span" style="WHITE-SPACE:pre;"></span>- Costs <a rel="nofollow" shape="rect" class="yiv7825439105" target="_blank" href="https://www.digikey.com/product-detail/en/P82B715DR/296-24729-1-ND/2092551">$2
a chip SOIC 8</a></div>
<div class="yiv7825439105"><span class="yiv7825439105Apple-tab-span" style="WHITE-SPACE:pre;"></span>- Can use CAT5
UTP</div>
<div class="yiv7825439105"><span class="yiv7825439105Apple-tab-span" style="WHITE-SPACE:pre;"></span>- Uses
open-drain lines - noise can be an issue and longer length takes lower pull-up
values sucking juice</div>
<div class="yiv7825439105"> </div>
<div class="yiv7825439105"> </div>
<div class="yiv7825439105">An Dual UART i2c to RS-485 transceiver:</div>
<div class="yiv7825439105"><span class="yiv7825439105Apple-tab-span" style="WHITE-SPACE:pre;"></span>- Such as the <a rel="nofollow" shape="rect" class="yiv7825439105" target="_blank" href="http://www.nxp.com/documents/data_sheet/SC16IS752_SC16IS762.pdf">NXP
SC16IS752</a> </div>
<div class="yiv7825439105"><span class="yiv7825439105Apple-tab-span" style="WHITE-SPACE:pre;"></span>- Can take
100kHz to 1000’ (rule of thumb - range = 100kHz / 10^8)</div>
<div class="yiv7825439105"><span class="yiv7825439105Apple-tab-span" style="WHITE-SPACE:pre;"></span>- Costs <a rel="nofollow" shape="rect" class="yiv7825439105" target="_blank" href="http://www.digikey.com/product-detail/en/SC16IS752IPW,128/568-11944-1-ND/5221977">$4
a chip - 28-TSSOP</a></div>
<div class="yiv7825439105"><span class="yiv7825439105Apple-tab-span" style="WHITE-SPACE:pre;"></span>- Can use CAT5
UTP</div>
<div class="yiv7825439105"><span class="yiv7825439105Apple-tab-span" style="WHITE-SPACE:pre;"></span>- Differential
signaling - more tolerant of noise</div>
<div class="yiv7825439105"><span class="yiv7825439105Apple-tab-span" style="WHITE-SPACE:pre;"></span>- Runs at 2.5 or
3.3V without degradation of performance</div>
<div class="yiv7825439105"> </div>
<div class="yiv7825439105">Looking at this list, I think I will try the RS-485 solution as well -
thanks for pointing this out Fred and I hope this comparison is helpful to
folks.</div>
<div class="yiv7825439105"> </div>
<div class="yiv7825439105">Thanks,</div>
<div class="yiv7825439105"> </div>
<div class="yiv7825439105">Chip</div>
<div class="yiv7825439105"> </div>
<div class="yiv7825439105"> </div>
<div class="yiv7825439105">
<div class="yiv7825439105"> </div>
<div class="yiv7825439105">
<blockquote class="yiv7825439105" type="cite">
<div class="yiv7825439105">On Sep 30, 2015, at 6:02 PM, <a rel="nofollow" shape="rect" class="yiv7825439105" ymailto="mailto:triembed-request@triembed.org" target="_blank" href="mailto:triembed-request@triembed.org">triembed-request@triembed.org</a>
wrote:</div>
<div class="yiv7825439105"> </div>
<div class="yiv7825439105">Send TriEmbed mailing list submissions to<br clear="none" class="yiv7825439105"><span class="yiv7825439105Apple-tab-span" style="WHITE-SPACE:pre;"></span><a rel="nofollow" shape="rect" class="yiv7825439105" ymailto="mailto:triembed@triembed.org" target="_blank" href="mailto:triembed@triembed.org">triembed@triembed.org</a><br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">To
subscribe or unsubscribe via the World Wide Web, visit<br clear="none" class="yiv7825439105"><span class="yiv7825439105Apple-tab-span" style="WHITE-SPACE:pre;"></span><a rel="nofollow" shape="rect" class="yiv7825439105" target="_blank" href="http://mail.triembed.org/mailman/listinfo/triembed_triembed.org">http://mail.triembed.org/mailman/listinfo/triembed_triembed.org</a><br clear="none" class="yiv7825439105">or,
via email, send a message with subject or body 'help' to<br clear="none" class="yiv7825439105"><span class="yiv7825439105Apple-tab-span" style="WHITE-SPACE:pre;"></span>triembed-request@triembed.org<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">You can
reach the person managing the list at<br clear="none" class="yiv7825439105"><span class="yiv7825439105Apple-tab-span" style="WHITE-SPACE:pre;"></span>triembed-owner@triembed.org<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">When
replying, please edit your Subject line so it is more specific<br clear="none" class="yiv7825439105">than "Re:
Contents of TriEmbed digest..."<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">Today's Topics:<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105"> 1.
Re: Fred Brooks presenting tonight on Centennial
Campus<br clear="none" class="yiv7825439105"> (Adam Haile)<br clear="none" class="yiv7825439105"> 2. Re: I2C range
extension (Rodney Radford)<br clear="none" class="yiv7825439105"> 3. Re: Fred Brooks presenting tonight on
Centennial Campus<br clear="none" class="yiv7825439105"> (Pete Soper)<br clear="none" class="yiv7825439105"> 4. Re:
I2C range extension (Chip McClelland) (Fred
Ebeling)<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">----------------------------------------------------------------------<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">Message:
1<br clear="none" class="yiv7825439105">Date: Wed, 30 Sep 2015 14:50:06 -0400<br clear="none" class="yiv7825439105">From: Adam Haile
<email@adamhaile.net><br clear="none" class="yiv7825439105">To: Rodney Radford
<ncgadgetry@gmail.com><br clear="none" class="yiv7825439105">Cc: TriEmbed Discussion
<triembed@triembed.org>, <span class="yiv7825439105Apple-tab-span" style="WHITE-SPACE:pre;"></span>trianglerobotics<br clear="none" class="yiv7825439105"><span class="yiv7825439105Apple-tab-span" style="WHITE-SPACE:pre;"></span><trianglerobotics@yahoogroups.com>,
<span class="yiv7825439105Apple-tab-span" style="WHITE-SPACE:pre;"></span>Triangle Linux
Users Group<br clear="none" class="yiv7825439105"><span class="yiv7825439105Apple-tab-span" style="WHITE-SPACE:pre;"></span>General Discussion
<trilug@trilug.org><br clear="none" class="yiv7825439105">Subject: Re: [TriEmbed] Fred Brooks presenting
tonight on Centennial<br clear="none" class="yiv7825439105"><span class="yiv7825439105Apple-tab-span" style="WHITE-SPACE:pre;"></span>Campus<br clear="none" class="yiv7825439105">Message-ID:<br clear="none" class="yiv7825439105"><span class="yiv7825439105Apple-tab-span" style="WHITE-SPACE:pre;"></span><CAG8g-TYsX+pF7F293jZg37zf_zR=3AV4Y_KBKdDPXV+v2oAtCg@mail.gmail.com><br clear="none" class="yiv7825439105">Content-Type:
text/plain; charset="utf-8"<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">Oh man... that's really tempting.
Thanks!<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">On Wed, Sep 30, 2015 at 2:46 PM, Rodney Radford via TriEmbed
<<br clear="none" class="yiv7825439105">triembed@triembed.org> wrote:<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">
<blockquote class="yiv7825439105" type="cite">Fred Brooks, author of "Mytical Man Month" and
project lead of the IBM/360<br clear="none" class="yiv7825439105">system, will be presenting tonight on
Centennial campus on the history of<br clear="none" class="yiv7825439105">computing.<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">If you have never
heard of Dr Brooks, you should read a little about his<br clear="none" class="yiv7825439105">career and show up
tonight to hear him
speak.<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">https://en.wikipedia.org/wiki/Fred_Brooks<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">If you know
who he is, you already know why you should attend.<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">More detail at the
link
below:<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">https://meetings.vtools.ieee.org/m/35685<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">_______________________________________________<br clear="none" class="yiv7825439105">Triangle,
NC Embedded Computing mailing
list<br clear="none" class="yiv7825439105">TriEmbed@triembed.org<br clear="none" class="yiv7825439105">http://mail.triembed.org/mailman/listinfo/triembed_triembed.org<br clear="none" class="yiv7825439105">TriEmbed
web site: http://TriEmbed.org<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105"></blockquote>-------------- next part
--------------<br clear="none" class="yiv7825439105">An HTML attachment was scrubbed...<br clear="none" class="yiv7825439105">URL:
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2<br clear="none" class="yiv7825439105">Date: Wed, 30 Sep 2015 15:04:21 -0400<br clear="none" class="yiv7825439105">From: Rodney Radford
<ncgadgetry@gmail.com><br clear="none" class="yiv7825439105">To: TriEmbed Discussion
<triembed@triembed.org><br clear="none" class="yiv7825439105">Subject: Re: [TriEmbed] I2C range
extension<br clear="none" class="yiv7825439105">Message-ID:<br clear="none" class="yiv7825439105"><span class="yiv7825439105Apple-tab-span" style="WHITE-SPACE:pre;"></span><CA+kfaxGN56iAhKCSsRDi7VzLZuH71vwxxxZVzZKEoGquUDAgBw@mail.gmail.com><br clear="none" class="yiv7825439105">Content-Type:
text/plain; charset="utf-8"<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">I used I2C to control about a dozen salt
water aquariums several years ago.<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">This involved a single PC
bit-banging I2C out a parallel port (so was slow)<br clear="none" class="yiv7825439105">to a temperature sensor
in each of the aquariums (some 30' away), sending<br clear="none" class="yiv7825439105">status out to a a couple
2x16 and 4x16 displays (I2C serial -> parallel -><br clear="none" class="yiv7825439105">LCD parallel
interface), and controlling the heaters.<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">This was for an outdoor,
unheated, uninsulated building where the water in<br clear="none" class="yiv7825439105">the salt water aquariums
had to be kept within a fairly narrow range. We<br clear="none" class="yiv7825439105">monitored the
temperature of the tanks and the external temp and would<br clear="none" class="yiv7825439105">start the heaters
in the water when we notice the temp dropping. This<br clear="none" class="yiv7825439105">replaced a
mechanical temperature setup where the heaters would turn on<br clear="none" class="yiv7825439105">once the water
got too cold, but by that time, the thermal mass of the<br clear="none" class="yiv7825439105">water prevented it
from heating fast enough.<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">Now all of this would be replaced with a
couple Arduinos, one devoted to<br clear="none" class="yiv7825439105">each tank, and a multi-drop serial bus to
report back to the PC, but this<br clear="none" class="yiv7825439105">was back about 20 years ago.<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">This
worked with no problems for the several years i worked with it.<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">A few
things we did:<br clear="none" class="yiv7825439105">* twisted pair<br clear="none" class="yiv7825439105">* I2C range extenders with 12v
pullups<br clear="none" class="yiv7825439105">* was not a noisy environment (outdoor building with only a single
power<br clear="none" class="yiv7825439105">drop and no other electrical devices)<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">This was far enough back
that you couldn't even buy the I2C devices in low<br clear="none" class="yiv7825439105">quantities, so companies
like Pure Unobtanium sprung up (Ed Nisley's<br clear="none" class="yiv7825439105">company - previous author in
Circuit Cellar Ink, and past Triangle Amateur<br clear="none" class="yiv7825439105">Robotics member) would buy
parts in the minimum quantity and sell to<br clear="none" class="yiv7825439105">hobbyists. Unfortunately by
the time he would burn through enough stock to<br clear="none" class="yiv7825439105">break even, they would be
available from other suppliers for less.<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">Also check out AccessBus - it
was based on I2C and was designed to be a<br clear="none" class="yiv7825439105">desktop peripheral
interface. Unfortunately it was not adopted and USB has<br clear="none" class="yiv7825439105">since taken
over this market.<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">So the short of it - yes, you can use I2C for longer
distances in some<br clear="none" class="yiv7825439105">circumstances.<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">On Tue, Sep 29, 2015 at 10:03
PM, Charles West via TriEmbed <<br clear="none" class="yiv7825439105">triembed@triembed.org> wrote:<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">
<blockquote class="yiv7825439105" type="cite">Hello,<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">Thanks again for all the good
discussion on electrical connectors.<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">We're still debating some of the
specifics for the CANInstall and/or<br clear="none" class="yiv7825439105">I2CPotential protocols. One of
the big things up in the air is how<br clear="none" class="yiv7825439105">reliable I2C is and how long the
range can be.<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">My impression is that having a I2C bus of more than a
meter or two is<br clear="none" class="yiv7825439105">considered pushing your luck. However, there seem
to be range<br clear="none" class="yiv7825439105">extender/repeater chips available that promise rather
drastically improved<br clear="none" class="yiv7825439105">range (such as the P82B715).<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">If I may ask,
what is the longest I2C bus you have built/seen?<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">How has your
experience been in terms of reliability?<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">What sort of bus speeds do
you tend to use?<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">The bus speed is driven by the master, so
theoretically you could have a<br clear="none" class="yiv7825439105">sub-hertz baud rate? Does this mean
that you could get a really long range<br clear="none" class="yiv7825439105">with a super slow baud rate or are
the edges not sharp enough to
be<br clear="none" class="yiv7825439105">detected?<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">Thanks,<br clear="none" class="yiv7825439105">Charlie<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">_______________________________________________<br clear="none" class="yiv7825439105">Triangle,
NC Embedded Computing mailing
list<br clear="none" class="yiv7825439105">TriEmbed@triembed.org<br clear="none" class="yiv7825439105">http://mail.triembed.org/mailman/listinfo/triembed_triembed.org<br clear="none" class="yiv7825439105">TriEmbed
web site: http://TriEmbed.org<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105"></blockquote>-------------- next part
--------------<br clear="none" class="yiv7825439105">An HTML attachment was scrubbed...<br clear="none" class="yiv7825439105">URL:
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3<br clear="none" class="yiv7825439105">Date: Wed, 30 Sep 2015 15:32:55 -0400<br clear="none" class="yiv7825439105">From: Pete Soper
<pete@soper.us><br clear="none" class="yiv7825439105">To: triembed@triembed.org<br clear="none" class="yiv7825439105">Subject: Re: [TriEmbed]
Fred Brooks presenting tonight on Centennial<br clear="none" class="yiv7825439105"><span class="yiv7825439105Apple-tab-span" style="WHITE-SPACE:pre;"></span>Campus<br clear="none" class="yiv7825439105">Message-ID:
<560C38E7.7090105@soper.us><br clear="none" class="yiv7825439105">Content-Type: text/plain;
charset=ISO-8859-1; format=flowed<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">WOW. Thanks very much for the notice,
Rod. This is truly one of the <br clear="none" class="yiv7825439105">grand old men of software engineering (and
he's much younger than I
<br clear="none" class="yiv7825439105">thought!)<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">-Pete<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">------------------------------<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">Message:
4<br clear="none" class="yiv7825439105">Date: Wed, 30 Sep 2015 14:18:13 -0400<br clear="none" class="yiv7825439105">From: "Fred Ebeling"
<FEbeling@ECPDesigns.com><br clear="none" class="yiv7825439105">To: "Charles McClelland"
<chip@mcclellands.org>,<br clear="none" class="yiv7825439105"><span class="yiv7825439105Apple-tab-span" style="WHITE-SPACE:pre;"></span><triembed@triembed.org><br clear="none" class="yiv7825439105">Subject: Re:
[TriEmbed] I2C range extension (Chip McClelland)<br clear="none" class="yiv7825439105">Message-ID:
<B812360D6960473488D05FE620FFFE2C@ECPDesigns><br clear="none" class="yiv7825439105">Content-Type:
text/plain; charset="utf-8"<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">This has been an interesting discussion,
but perhaps a bit of history would<br clear="none" class="yiv7825439105">help. The original I2C
protocal was developed by Philips to interconnect<br clear="none" class="yiv7825439105">HIFI equipment together
and still be able to use a 3 connector plug. It was<br clear="none" class="yiv7825439105">designed for
short distances, perhaps 10 feet max.<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">To go further the normal
?standard? is to use RS 485 (or RS 422) standard. This<br clear="none" class="yiv7825439105">uses three
wires, a ground, and two signal wires that are opposite of each other.<br clear="none" class="yiv7825439105">So
when the TX+ sends a ?1?, the TX- sends a ?0?. The wires are also
terminated<br clear="none" class="yiv7825439105">usually with a 120 ohm resistor on both ends. Thou some
ignore this rule.<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">RS-485 can go thousands of feet. I have set up
systems with the length of over<br clear="none" class="yiv7825439105">4000? between the controller and the node.
<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">Speed is based on distance, the major limitation is the ?capacitance
of the wire?. This<br clear="none" class="yiv7825439105">will cause the leading and falling edge to degrade
and limit the speed to around 10KHz<br clear="none" class="yiv7825439105">for long distances. Shorter
distances (100?) can get up to 1 MHz.<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">The problem thou is this is one
way communications at a time. Think of it like the<br clear="none" class="yiv7825439105">old CB
radios. You send a packet to the ?good old boy? at the end node and say
?Over?<br clear="none" class="yiv7825439105">so the end node can respond back.<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">RS 422 eliminates this by
having separate xmit and rec pairs. <br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">In either case, the RS485 IC
are reasonable priced and there are even standards for<br clear="none" class="yiv7825439105">the connectors and
connections.<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">Fred Ebeling<br clear="none" class="yiv7825439105">ECP Designs<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">From: Charles
McClelland via TriEmbed <br clear="none" class="yiv7825439105">Sent: Wednesday, September 30, 2015 1:54 PM<br clear="none" class="yiv7825439105">To:
triembed@triembed.org <br clear="none" class="yiv7825439105">Subject: [TriEmbed] I2C range extension (Chip
McClelland)<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">Charlie, <br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">I agree with John?s recommendations but
wanted to pass on my experience. I can reliably go 8? with i2c
under the following conditions:<br clear="none" class="yiv7825439105">- Cat5 cable and paying attention to which
pairs are used for SDA / SCL<br clear="none" class="yiv7825439105">- Speed set to 100kHz <br clear="none" class="yiv7825439105">- 4.7k pull-ups to
3.3V<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">I need to get to 50? so I have ordered a few P82B715 chips.
These chips advertise to get to 50? but only if you are using 5V logic so we
will see if they can go 50? at 3.3V. I will share my results at the next
meeting.<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">Hope this helps,<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">Chip<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">On Sep 30, 2015,
at 1:00 PM, triembed-request@triembed.org wrote:<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">Send TriEmbed mailing
list submissions to<br clear="none" class="yiv7825439105">triembed@triembed.org<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">To subscribe or
unsubscribe via the World Wide Web,
visit<br clear="none" class="yiv7825439105">http://mail.triembed.org/mailman/listinfo/triembed_triembed.org<br clear="none" class="yiv7825439105">or,
via email, send a message with subject or body 'help'
to<br clear="none" class="yiv7825439105">triembed-request@triembed.org<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">You can reach the person managing
the list at<br clear="none" class="yiv7825439105">triembed-owner@triembed.org<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">When replying, please edit
your Subject line so it is more specific<br clear="none" class="yiv7825439105">than "Re: Contents of TriEmbed
digest..."<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">Today's Topics:<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105"> 1. Re: Bulk LED
Order (Adam Haile)<br clear="none" class="yiv7825439105"> 2. I2C range extension (Charles
West)<br clear="none" class="yiv7825439105"> 3. Re: I2C range extension (John
Vaughters)<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">----------------------------------------------------------------------<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">Message:
1<br clear="none" class="yiv7825439105">Date: Tue, 29 Sep 2015 13:58:17 -0400<br clear="none" class="yiv7825439105">From: Adam Haile
<email@adamhaile.net><br clear="none" class="yiv7825439105">To: "triembed@triembed.org"
<triembed@triembed.org><br clear="none" class="yiv7825439105">Subject: Re: [TriEmbed] Bulk LED
Order<br clear="none" class="yiv7825439105">Message-ID:<br clear="none" class="yiv7825439105"><CAG8g-TaEQgjJRs4GGKhWiMPj-NTKE_iUxbLXbdqY-6z6Nn0fTQ@mail.gmail.com><br clear="none" class="yiv7825439105">Content-Type:
text/plain; charset="utf-8"<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">Final call! Putting in quote request
tomorrow. Let me know if you want<br clear="none" class="yiv7825439105">anything.<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">On Fri, Sep 11, 2015 at
11:14 AM, Adam Haile <email@adamhaile.net>
wrote:<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105"> I recently had to tear down my old porch
lighting install when we had our<br clear="none" class="yiv7825439105"> house repainted, so I'm going
to be ordering a bunch of new lights from my<br clear="none" class="yiv7825439105"> supplier in
China.<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105"> Like last time, if anyone wants to get in on the
order, the pricing is a<br clear="none" class="yiv7825439105"> huge discount from normal suppliers
like Adafruit, Sparkfun, Amazon, eBay,<br clear="none" class="yiv7825439105">
etc.<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105"> I don't take a profit, the prices in the pricing
lists (GDrive link below)<br clear="none" class="yiv7825439105"> are direct from the manufacturer.
The major point here is to save on<br clear="none" class="yiv7825439105"> shipping for everyone.
Which I'll divide between all buyers based on the<br clear="none" class="yiv7825439105"> percentage
of the overall purchase price which is yours.<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105"> Pricing
lists here:<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">
https://drive.google.com/folderview?id=0B7a_WsLpan5-SEl5TjAtTjctZm8&usp=sharing<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">
So, if you would like anything, please let me know in the next couple
of<br clear="none" class="yiv7825439105"> weeks and give me the exact model number and quantity. Most
things come in<br clear="none" class="yiv7825439105"> 5m rolls, so you can tell me rolls or
meters.<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105"> Once I get everyone's details I'll will request a
final quote (some of the<br clear="none" class="yiv7825439105"> pricing can vary by quantity) and
then send everyone their final cost.<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105"> *PLEASE NOTE*: Since
I have to pay the manufacturer via PayPal, you *MUST* pay<br clear="none" class="yiv7825439105"> me
via Paypal. That way no money has to go through my own personal
bank<br clear="none" class="yiv7825439105"> accounts first. So, sorry, no cash or checks. And payment
must go through<br clear="none" class="yiv7825439105"> prior to submitting the final order to the
manufacturer. Sorry if this is<br clear="none" class="yiv7825439105"> an inconvenience, but it's the
easiest way for me to do it.<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105"> Let me
know.<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105"> Adam<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">-------------- next part
--------------<br clear="none" class="yiv7825439105">An HTML attachment was scrubbed...<br clear="none" class="yiv7825439105">URL:
<http://mail.triembed.org/pipermail/triembed_triembed.org/attachments/20150929/48eba6b8/attachment-0001.html><br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">------------------------------<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">Message:
2<br clear="none" class="yiv7825439105">Date: Tue, 29 Sep 2015 22:03:01 -0400<br clear="none" class="yiv7825439105">From: Charles West
<crwest@ncsu.edu><br clear="none" class="yiv7825439105">To: TriEmbed
<triembed@triembed.org><br clear="none" class="yiv7825439105">Subject: [TriEmbed] I2C range
extension<br clear="none" class="yiv7825439105">Message-ID:<br clear="none" class="yiv7825439105"><CAGojqSk0_4x63vjm0EhqRag56fW9y38j9qfJzOF8sRwzW_tfLQ@mail.gmail.com><br clear="none" class="yiv7825439105">Content-Type:
text/plain; charset="utf-8"<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">Hello,<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">Thanks again for all the good
discussion on electrical connectors.<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">We're still debating some of the
specifics for the CANInstall and/or<br clear="none" class="yiv7825439105">I2CPotential protocols. One of
the big things up in the air is how<br clear="none" class="yiv7825439105">reliable I2C is and how long the range
can be.<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">My impression is that having a I2C bus of more than a meter or
two is<br clear="none" class="yiv7825439105">considered pushing your luck. However, there seem to be
range<br clear="none" class="yiv7825439105">extender/repeater chips available that promise rather drastically
improved<br clear="none" class="yiv7825439105">range (such as the P82B715).<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">If I may ask, what is the
longest I2C bus you have built/seen?<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">How has your experience been in
terms of reliability?<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">What sort of bus speeds do you tend to
use?<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">The bus speed is driven by the master, so theoretically you could
have a<br clear="none" class="yiv7825439105">sub-hertz baud rate? Does this mean that you could get a
really long range<br clear="none" class="yiv7825439105">with a super slow baud rate or are the edges not sharp
enough to be<br clear="none" class="yiv7825439105">detected?<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">Thanks,<br clear="none" class="yiv7825439105">Charlie<br clear="none" class="yiv7825439105">-------------- next
part --------------<br clear="none" class="yiv7825439105">An HTML attachment was scrubbed...<br clear="none" class="yiv7825439105">URL:
<http://mail.triembed.org/pipermail/triembed_triembed.org/attachments/20150929/064d0dab/attachment-0001.html><br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">------------------------------<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">Message:
3<br clear="none" class="yiv7825439105">Date: Wed, 30 Sep 2015 12:54:03 +0000 (UTC)<br clear="none" class="yiv7825439105">From: John Vaughters
<jvaughters04@yahoo.com><br clear="none" class="yiv7825439105">To: Charles West <crwest@ncsu.edu>,
TriEmbed <triembed@triembed.org><br clear="none" class="yiv7825439105">Subject: Re: [TriEmbed] I2C range
extension<br clear="none" class="yiv7825439105">Message-ID:<br clear="none" class="yiv7825439105"><1421720024.2476926.1443617643320.JavaMail.yahoo@mail.yahoo.com><br clear="none" class="yiv7825439105">Content-Type:
text/plain; charset=UTF-8<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">Charlie,<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">The biggest problem I would
be concerned about on i2c over a long distance is noise susceptibility that
could affect reliability. So the importance of reliable communication is at
question. I guess the first question would be, do you have an environment that
is noisey? Then, Do you care if you have interruptions? If your environment is
fairly clean of noise and you can live with communication interruptions, then
long i2c may be a good low cost solution for long runs. <br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">Here is what
you may want to consider. <br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">1. Take control of the pull up resistors by
disabling them on the chip.<br clear="none" class="yiv7825439105">2. Tune the pull up resistors by starting at a
safe low level and then increase them until you stop getting communication at
the length you are running. Then back down. Keep in mind that you will gain
more reliability as you reduce the pull ups.<br clear="none" class="yiv7825439105">3. Twisted pair cables would
be your first attack on noise.<br clear="none" class="yiv7825439105">4. If you still encounter noise, consider
ferrite beads to supress. This is best done if you have an idea of the noise
frequency. <br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">The alternative is if you truly desire reliable
communications, then 485/CAN is the way to go. CAN being the most expensive,
but gives you the similar capability to i2c with the ad hoc interruption
communication capability. Or better stated an adhoc like network with a
priority assignment.<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">I personally never ran i2c that long and cannot
answer those questions. I generally have used 485 the most. The TI chips are
usually the lowest cost for communication. For some reason people love the
half duplex, but I prefer the full duplex.<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">I would be curious to know
how far you make i2c run if you go that route.<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">John
Vaughters<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">On Tuesday, September 29, 2015 10:03 PM, Charles West
via TriEmbed <triembed@triembed.org>
wrote:<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">Hello,<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">Thanks again for all the good discussion
on electrical connectors. <br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">We're still debating some of the specifics
for the CANInstall and/or I2CPotential protocols. One of the big things
up in the air is how reliable I2C is and how long the range can be.<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">My
impression is that having a I2C bus of more than a meter or two is considered
pushing your luck. However, there seem to be range extender/repeater
chips available that promise rather drastically improved range (such as the
P82B715). <br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">If I may ask, what is the longest I2C bus you have
built/seen?<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">How has your experience been in terms of
reliability?<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">What sort of bus speeds do you tend to use?<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">The bus
speed is driven by the master, so theoretically you could have a sub-hertz
baud rate? Does this mean that you could get a really long range with a
super slow baud rate or are the edges not sharp enough to be
detected?<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">Thanks,<br clear="none" class="yiv7825439105">Charlie<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">_______________________________________________<br clear="none" class="yiv7825439105">Triangle,
NC Embedded Computing mailing
list<br clear="none" class="yiv7825439105">TriEmbed@triembed.org<br clear="none" class="yiv7825439105">http://mail.triembed.org/mailman/listinfo/triembed_triembed.org<br clear="none" class="yiv7825439105">TriEmbed
web site:
http://TriEmbed.org<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">------------------------------<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">Subject:
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Footer<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">_______________________________________________<br clear="none" class="yiv7825439105">TriEmbed
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31<br clear="none" class="yiv7825439105">****************************************<br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105"><br clear="none" class="yiv7825439105">--------------------------------------------------------------------------------<br clear="none" class="yiv7825439105">_______________________________________________<br clear="none" class="yiv7825439105">Triangle,
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list<br clear="none" class="yiv7825439105">TriEmbed@triembed.org<br clear="none" class="yiv7825439105">http://mail.triembed.org/mailman/listinfo/triembed_triembed.org<br clear="none" class="yiv7825439105">TriEmbed
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<div class="yiv7825439105"> </div></div><div class="yiv7825439105">
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_______________________________________________<br clear="none" class="yiv7825439105">Triangle, NC Embedded
Computing mailing
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