we have developed a modem with the GE864 Quad Automotive module. All works fine with this module. Data is transfered via GPRS. The system running on our modem is a linux system that establishes a ppp connection via serial port and GPRS module to our server.
Then we changed to the GE864 Quad Automotive V2 module and we first thought that this was working like its predecessor. We neither changed software nor the hardware (apart from the V2 module). The modem registers itself at our provider and gets an IP. So we are able to exchange data.
But problem is in detail. After a while (the time always varies), when our application is running on the modem which exchanges data with our server (asynchronously in both directions), the connection is suddenly getting more and more bumpy (the response times are getting longer) and finally it stops. When this happens the module does not exchange any data (either over serial port to our modem-cpu or via GPRS to the server). I have debugged a lot… . To exclude a hardware connection failure, we bought an evaluation kit with the V2 module which we have connected to our modem-board. The result was the same.
Now the strange thing: Sometimes it happens up to 2 minutes after our program has stopped connection to server because of timeout, that the module transfers all the data the server had sent (until it got its own timeout) over serial port. It looks like as if the module would flush its buffers. Because of this behaviour I would assume something is getting confused within the buffer of the V2 module.
I have examined the tracelogs of the module, too. I found some message that I cannot direclty connect to our problem, but perhaps someone knows:
FATAL> Mon Activity stopped by DSP
L1 ERR : Invalid ptr detected !
WARNING: SY detected reuse of Timer 114 at 1156216
WARNING: RR The value of variable is 10607
WARNING: RR The value of variable is -1
Perhaps the invalid pointer is connected to the assumed buffer problem?
I tried copying data from and to our modem (with V2 module) with WinSCP. When using this program I had no connection problems. But I saw one big difference when watching the traffic from serial port. If I use WinSCP the amount of bytes the are transfered over serial port in every direction is ver high. And data is transfered in alternating directions. When using our program the data packets transfered over serial port are much smaller.
The software versions of the modules are:
GE864 Quad Automotive: 07.03.030
GE864 Quad Automotive V2: 10.00.032
Thanks in advance!
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