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Mark,<br>
<br>
transparent chunk splitting seems to be non-trivial, so I split my
data transfers. Everything's working fine again, so I'll merge into
the master next if you don't object.<br>
<br>
Btw, AT+CIPSEND? gave me 1460 bytes, so that's supposed to be the
size limit we should keep in mind until we find a better solution.<br>
<br>
@Nikolay: please note, that's the total size that can be sent within
one net_msg_start() ... net_msg_send(), the buffer size
(net_scratchpad) further limits a single MSG line to currently 199
bytes max.<br>
<br>
Regards,<br>
Michael<br>
<br>
<br>
<div class="moz-cite-prefix">Am 31.12.2012 16:23, schrieb Michael
Balzer:<br>
</div>
<blockquote cite="mid:50E1AE0F.1050304@expeedo.de" type="cite">Mark,
<br>
<br>
I think I found my link dropping problem: scanning a diag log I
took, I found out CIPSEND will fail with a plain "ERROR" if the
data size exceeds about 1500 bytes. I guess that's either the
SIM908 buffer size or the max network packet size. I thought the
SIM908 would handle dividing data into packets as needed. The
SIM908 manual mentions the max packet size depends on network
status and should be queried by "AT+CIPSEND?". After the overrun
net_state_activity() will not recognize "ERROR" to terminate the
pending msg, so will run into the timeout and start a network
re-init.
<br>
<br>
My battery status data exceeds 1500 bytes on first run and later
on if enough cells need updates. I'll think about how to split up
data packets into multiple CIPSENDs. Would be nice if the net
functions take care of this transparently.
<br>
<br>
A secondary issue turned up from the diag log: the SIM908 crashed
in the middle of a CIPSEND command while the module continued to
run normally. The module still thought it's in NET_STATE_READY, so
did not re-initalize the modem. The connection could then be
established on the next CIPSTART, but the complete INIT stuff had
not been done. So it seems independant SIM908 resets need to be
handled as well, and they can occur anytime. I'll see if I can
solve that too.
<br>
<br>
Regards,
<br>
Michael
<br>
<br>
<br>
Am 30.12.2012 15:42, schrieb Michael Balzer:
<br>
<blockquote type="cite">I hesitate to merge into the master
because I currently have link / connectivity problems,
especially during driving. I introduced a GPS logging to
optimize my antenna positions and managed to get some really
nice tracks three days ago, so I don't think this is related to
my changes... but I'm not 100% sure. I tried different antenna
positions and another GSM network, but the connection keeps
dropping when moving the car, and GPS position updates need
minutes. Could be weather conditions ...or some tricky race
condition bug?
<br>
</blockquote>
<br>
<br>
<br>
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<br>
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<br>
<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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