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I've pushed my SIMCOM changes. With these optimizations, fifo
overflows and frame errors have dropped significantly:<br>
<blockquote><tt>OVMS# sim stat de</tt><br>
<tt>Network Registration: RegisteredHome</tt><br>
<tt>Provider: congstar</tt><br>
<tt>Signal: -97 dBm</tt><br>
<br>
<tt>State: NetMode</tt><br>
<tt> Ticker: 73099</tt><br>
<tt> User Data: 0</tt><br>
<tt> HW FIFO overflows: 21</tt><br>
<tt> Buffer overflows: 0</tt><br>
<br>
<tt> Mux</tt><br>
<tt> Status: up</tt><br>
<tt> Open Channels: 4</tt><br>
<tt> Framing Errors: 24</tt><br>
<tt> Last RX frame: 1 sec(s) ago</tt><br>
<tt> RX frames: 151452</tt><br>
<tt> TX frames: 5472</tt><br>
<br>
<tt>PPP: Connected on channel: #2</tt><br>
<br>
<tt>GPS: Connected on channel: #1</tt><br>
<tt> Status: enabled</tt><br>
<tt> Time: enabled</tt><br>
</blockquote>
…but the overflow frequency differs between my modules (both v3.1,
the one with the first gen CP2102 has more overflows), and I can
still see a direct relation to Wifi.<br>
<br>
With Wifi switched completely off, no overflows occurred over a
period of ~5 hours. As soon as Wifi was reactivated (regardless of
the mode), the errors were back.<br>
<br>
<br>
<div class="moz-cite-prefix">Am 23.10.19 um 09:31 schrieb Mark
Webb-Johnson:<br>
</div>
<blockquote type="cite"
cite="mid:264CC7C9-54CB-4B5D-9CD9-DB1CAAEFBDB7@webb-johnson.net">
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
While there is flow control on the USB side, I don’t think there
is any between the ESP32 and the CP2102. See Espressif’s example
DEVKIT-C schematic:
<div class=""><br class="">
</div>
<blockquote style="margin: 0 0 0 40px; border: none; padding:
0px;" class="">
<div class=""><a
href="https://dl.espressif.com/dl/schematics/ESP32-Core-Board-V2_sch.pdf"
class="" moz-do-not-send="true">https://dl.espressif.com/dl/schematics/ESP32-Core-Board-V2_sch.pdf</a></div>
</blockquote>
<div class="">
<div><br class="">
</div>
<div>or the OVMS one (which we based on DEVKIT-C). Just RX and
TX data lines to the ESP32.</div>
</div>
</blockquote>
<br>
What about the RTS/CTS lines connected to IO13 & IO15 in the
core board?<br>
<br>
<blockquote type="cite"
cite="mid:264CC7C9-54CB-4B5D-9CD9-DB1CAAEFBDB7@webb-johnson.net">
<div class="">
<div>However, during flashing there is pretty much nothing else
running on the system and no high level operating system.</div>
</div>
</blockquote>
<br>
Indeed.<br>
<br>
Regards,<br>
Michael<br>
<br>
<blockquote type="cite"
cite="mid:264CC7C9-54CB-4B5D-9CD9-DB1CAAEFBDB7@webb-johnson.net">
<div class="">
<div>The good news is that these are very very short data lines.
Just a few inches, I think. I did look at the signals in the
early days of the project, and they seem quite clean.</div>
<div><br class="">
</div>
<div>The GMS MUX flow control is at the frame level. I would
guess that several frames would still need to be fit into the
buffer for it to be effective. It is implemented on a
per-channel basis, and a short description (from the blox
manual) is:</div>
<div><br class="">
</div>
</div>
<blockquote style="margin: 0 0 0 40px; border: none; padding:
0px;" class="">
<div class="">
<div><a
href="http://read.pudn.com/downloads406/ebook/1729787/MuxImplementation_ApplicationNote_(WLS-CS-11002).pdf"
class="" moz-do-not-send="true">http://read.pudn.com/downloads406/ebook/1729787/MuxImplementation_ApplicationNote_(WLS-CS-11002).pdf</a></div>
</div>
<div><span style="font-family: "Frutiger 45
Light,Bold"; font-size: 14pt;" class=""><br class="">
</span></div>
<div><span style="font-family: "Frutiger 45
Light,Bold"; font-size: 14pt;" class="">6.3
FlowControlonvirtualchannels</span></div>
<div>
<div class="page" title="Page 15">
<div class="layoutArea">
<div class="column">
<p class=""><span style="font-size: 10.000000pt;
font-family: 'Frutiger 45 Light'" class="">The Flow
control of the virtual channel is implemented in
terms of MSC packets with the FC bit. If the
application processor sets the FC bit to 1 for a
particular DLC, the TE does not send data to the
application
processor for that DLC until FC returns to 0 for the
same DLC. The TE has limited resources for buffering
data, so
if the DLC is involved in large data transfers (for
example downloading data through a GPRS connection)
a buffer
overflow may occur if the time between FC=1 and FC=0
is too long; in this case data may be lost and there
is no
error indication.
</span></p>
<p class=""><span style="font-size: 10.000000pt;
font-family: 'Frutiger 45 Light'" class="">The
application processor should avoid (if possible) the
use of this feature or keep the time interval with
the
FC=1 as small as possible. </span></p>
</div>
</div>
</div>
</div>
</blockquote>
<div class="">
<div><br class="">
</div>
<div>I never really did any optimisation of the SIMCOM (or MUX)
driver at all. The MUX in particular was written by looking at
other implementations, as the protocol specification has gone
the way of most standards body specifications and is mostly
undecipherable. I think there is some opportunity for
improvement (but given our low bandwidth requirements at the
time we never had the incentive). Flow control is not
implemented at all.</div>
<div><br class="">
</div>
<div>Regards, Mark</div>
<div><br class="">
<blockquote type="cite" class="">
<div class="">On 23 Oct 2019, at 3:01 PM, Michael Balzer
<<a href="mailto:dexter@expeedo.de" class=""
moz-do-not-send="true">dexter@expeedo.de</a>> wrote:</div>
<br class="Apple-interchange-newline">
<div class="">
<div class="">Mark,<br class="">
<br class="">
also not trying to sound too negative… but please read:
<a
href="https://github.com/openvehicles/Open-Vehicle-Monitoring-System-3/issues/274"
class="" moz-do-not-send="true">https://github.com/openvehicles/Open-Vehicle-Monitoring-System-3/issues/274</a><br
class="">
<br class="">
The flashing process is done with hardware flow control.
With Wifi enabled, we cannot even handle 115 kbit
without fifo overflows.<br class="">
<br class="">
We can try the MUX flow control you mentioned, but will
it be able to throttle transmission within frames longer
than the HW FIFO?<br class="">
<br class="">
Btw, I've got an improvement on fifo overflow recovery
in testing, if you want to work on this, I can push my
changes this evening.<br class="">
<br class="">
Regards,<br class="">
Michael<br class="">
<br class="">
<br class="">
Am 23.10.19 um 08:50 schrieb Mark Webb-Johnson:<br
class="">
<blockquote type="cite" class="">But perhaps I am
unintentionally sounding too negative...<br class="">
<br class="">
The biggest hurdle to this working technically is
undoubtedly the LWIP support for SNAT and routing. If
the library you caption (jonask1337/esp-lwip) solves
that, it makes this technically feasible.<br class="">
<br class="">
My comments on baud rate on the UART link between
ESP32 and SIMCOM are more about the practicality of
it. That could be tested with a few simple
modifications to our SIMCOM driver, to see how fast it
could actually be driven. I know we get up to about
1Mbps for firmware flashing without an issue, and the
ESP32 hardware UART is up to 5Mbps.<br class="">
<br class="">
It would be a fantastic feature to have, and
incredibly useful.<br class="">
<br class="">
Regards, Mark.<br class="">
<br class="">
<blockquote type="cite" class="">On 23 Oct 2019, at
2:33 PM, Mark Webb-Johnson <<a
href="mailto:mark@webb-johnson.net" class=""
moz-do-not-send="true">mark@webb-johnson.net</a>>
wrote:<br class="">
<br class="">
The connection between the SIMCOM and the ESP32 is
115,200 baud. That could be increased (in software),
and there is software flow control on the GSM MUX we
use (although I have no idea if SIMCOM implements
it); but without hardware flow control lines I don’t
think it could/would approach 3G speeds.<br class="">
<br class="">
The alternative is to swap it around. Put the modem
and the SIM in some other device designed for that
purpose, and have OVMS connect to that as a WiFi
client.<br class="">
<br class="">
Regards, Mark.<br class="">
<br class="">
<blockquote type="cite" class="">On 23 Oct 2019, at
2:23 PM, Peter Lord <<a
href="mailto:plord12@gmail.com" class=""
moz-do-not-send="true">plord12@gmail.com</a>>
wrote:<br class="">
<br class="">
Hi All,<br class="">
<br class="">
I've been lurking here for a while still debating
wether to ditch my autopi in favour of OVMS.<br
class="">
<br class="">
One thing thats held me back is to find a way to
use the wifi hotspot as a NAT router - this is <br
class="">
useful to allow my sat nav to get traffic and
charging point updates. As far as I can see on <br
class="">
the web page this isn't currently supported.<br
class="">
<br class="">
However I did see a couple of projects that adds
NAT support to lwip :<br class="">
<br class="">
<span class="Apple-tab-span" style="white-space:pre"> </span><a
href="https://github.com/martin-ger/lwip_nat_arduino" class=""
moz-do-not-send="true">https://github.com/martin-ger/lwip_nat_arduino</a><br
class="">
<span class="Apple-tab-span" style="white-space:pre"> </span><a class="moz-txt-link-freetext" href="https://github.com/jonask1337/esp-lwip">https://github.com/jonask1337/esp-lwip</a><br
class="">
<br class="">
Does anyone know if adding NAT has a fighting
chance ?<br class="">
<br class="">
Cheers,<br class="">
<br class="">
Pete<br class="">
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<br class="">
<br class="">
-- <br class="">
Michael Balzer * Helkenberger Weg 9 * D-58256 Ennepetal<br
class="">
Fon 02333 / 833 5735 * Handy 0176 / 206 989 26<br
class="">
<br class="">
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</blockquote>
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<pre class="moz-signature" cols="160">--
Michael Balzer * Helkenberger Weg 9 * D-58256 Ennepetal
Fon 02333 / 833 5735 * Handy 0176 / 206 989 26
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