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Mark,<br>
<br>
I also see the current modem communication layer as a problem
source. The read buffer only takes 128 bytes, which will not be
sufficient for many situations -- e.g. a GPS response now needs
already two NMEA sentences adding up to about 108 bytes -- come in
another modem answer before the buffer gets handled, and bang we
go...<br>
<br>
The multiplex mode is quite interesting, didn't know this before --
although a really fully asynchronous modem comm handling would not
need that, I think. But it would need more buffer RAM...<br>
<br>
Hm... the SIM908 manual says: "In Multiplex mode, it is recommended
to use the hardware flow control."<br>
<br>
As far as I understand the circuit schemes the current hardware does
not connect RTS/CTS (pins 66+67) -- right?<br>
<br>
Regards,<br>
Michael<br>
<br>
<br>
<div class="moz-cite-prefix">Am 30.04.2013 03:28, schrieb Mark
Webb-Johnson:<br>
</div>
<blockquote
cite="mid:605E7C89-F120-47B1-967E-BEB2D8AD7942@webb-johnson.net"
type="cite">Michael,
<div><br>
</div>
<div>Looking at the design for 3G modules, I noticed something
recommended for those modules that seems to be supported for the
SIM900 base we use (both SIM900 OVMS v1 and SIM908 OVMS v2).
CMUX mode.</div>
<div><br>
</div>
<blockquote class="webkit-indent-blockquote" style="margin: 0 0 0
40px; border: none; padding: 0px;">
<div><a moz-do-not-send="true"
href="http://www.m2m-platforms.com/seminars/2007seminar_material/Telit_CMUX_2_M2M_Platforms_seminar_2007.pdf">http://www.m2m-platforms.com/seminars/2007seminar_material/Telit_CMUX_2_M2M_Platforms_seminar_2007.pdf</a></div>
</blockquote>
<div><br>
</div>
<div>This is GSM 7.10 TE-MS multiplexor protocol.</div>
<div><br>
</div>
<div>The main problem we have is co-ordinating all the different
comms channels of OVMS onto a single serial link to the modem.
Incoming SMSes, status indicators, outgoing GPRS TCP data, etc,
all run over each other.</div>
<div><br>
</div>
<div>The CMUX protocol appears to allow us to have 3 (or 4?)
virtual async links, over a single physical async port. We could
use one for SMS, another for TCP, and a third for GPS polling.
The 3G modules even allow the GPS NMEA data to be streamed back
over one of the virtual ports (but I don't think that is
available in the SIM908 module we use - hard to tell as the CMUX
documents focus on SIM900 not SIM908 [the SIM908 embeds SIM900
and adds GPS]).</div>
<div><br>
</div>
<div>It would mean some major restructuring of the comms layer
(NET), and we would have to build a small library to
encode/decode GSM 7.10, but may be a much more stable approach
in the long-term.</div>
<div><br>
</div>
<div>SIMCOM seem to implement a subset of the full GSM 7.10
functionality. Here's the manual on it for SIM900:</div>
<div><br>
</div>
<blockquote class="webkit-indent-blockquote" style="margin: 0 0 0
40px; border: none; padding: 0px;">
<div><a moz-do-not-send="true"
href="http://www.mt-system.ru/sites/default/files/sim900_multiplexer_user_manual_application_note_v1.3.pdf">http://www.mt-system.ru/sites/default/files/sim900_multiplexer_user_manual_application_note_v1.3.pdf</a></div>
<div><br>
</div>
<div><img id="f9ffe935-11e5-4e60-b823-d992f8920e08"
apple-width="yes" apple-height="yes"
src="cid:part3.07010803.02070404@expeedo.de" width="480"
height="592"></div>
</blockquote>
<div><br>
</div>
<div>Regards, Mark.</div>
<div><br>
<div>
<div>On 29 Apr, 2013, at 11:48 PM, Michael Balzer 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"> Am 28.04.2013 17:06,
schrieb Michael Balzer:<br>
<blockquote cite="mid:517D3AED.40206@expeedo.de"
type="cite">
<meta content="text/html; charset=ISO-8859-1"
http-equiv="Content-Type">
I just checked in my fix for the USSD reply handler. My
tests with streaming enabled did not produce any more
crashes, so I think that was the problem.<br>
</blockquote>
<br>
I was wrong, it's still crashing. I have to dig deeper it
seems.<br>
<br>
Has anyone observed crashes with streaming mode on other
vehicles, or is this a Twizy specific bug now?<br>
<br>
Thanks,<br>
Michael<br>
<br>
<pre class="moz-signature" cols="72">--
Michael Balzer * Paradestr. 8 * D-42107 Wuppertal
Fon 0202 / 272 2201 * Handy 0176 / 206 989 26
</pre>
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<pre class="moz-signature" cols="72">--
Michael Balzer * Paradestr. 8 * D-42107 Wuppertal
Fon 0202 / 272 2201 * Handy 0176 / 206 989 26
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