[Ovmsdev] sprintf / crashes

[Mark Webb-Johnson]

Michael,

Not too surprising, and I think your approach is good. The main limiting factor we have is RAM, and doing any sort of big buffering at the framework level will be hard. I think it is better to limit at the module level (as you have done).

It looks good for a master merge.

Regards, Mark

On 2 Jan, 2013, at 4:37 AM, Michael Balzer wrote:

> Mark,
> 
> 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.
> 
> 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.
> 
> @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.
> 
> Regards,
> Michael
> 
> 
> Am 31.12.2012 16:23, schrieb Michael Balzer:
>> Mark, 
>> 
>> 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. 
>> 
>> 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. 
>> 
>> 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. 
>> 
>> Regards, 
>> Michael 
>> 
>> 
>> Am 30.12.2012 15:42, schrieb Michael Balzer: 
>>> 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? 
>> 
>> 
>> 
>> 
>> _______________________________________________
>> OvmsDev mailing list
>> OvmsDev at lists.teslaclub.hk
>> http://lists.teslaclub.hk/mailman/listinfo/ovmsdev
> 
> -- 
> Michael Balzer * Paradestr. 8 * D-42107 Wuppertal
> Fon 0202 / 272 2201 * Handy 0176 / 206 989 26
> <dexter.vcf>_______________________________________________
> OvmsDev mailing list
> OvmsDev at lists.teslaclub.hk
> http://lists.teslaclub.hk/mailman/listinfo/ovmsdev

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openvehicles.com/pipermail/ovmsdev/attachments/20130102/a21172c5/attachment.htm>