Regarding Sierra wireless sl8082 hang issue

Legacy General
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  1. We have tried flashing the modem multiple times in a short span of time, but the modem is getting hung up in the middle of the execution. If we leave the modem by turning it off for 30 minutes to 1 hour and powering it ON again, it works properly as it should. Could there be a specific issue causing this?

  2. When a GPRS failure occurs, is there a particular reason behind it, we are getting error 36 and after manually powering OFF and powering ON, the GPRS again reconnects but after a few days the same error 36 happens. To resolve the issue, is there any error handling for GPRS error setup, other than powering ON and OFF the modem or soft reset in the modem?

  3. Does “WIP_BEV_ME_UNREG” refer to an issue on the SIM server-side or a code-related problem, in this context we are using GPRS bearer.

4.The RTC is responsible for the timestamp logging of the debug logs but the timing is not in order when it comes to timestamp. The timestamp is normal until an error occurs and after the error has occurred, the timestamp for logging the debug logs is not in order. Is there specific reason for this issue? For exmple, we are seeing the logs that should at 8:30 AM, are comming in between 9:00 AM to 9:30 AM.

  1. When the DCU (Data Concentrator Unit - collects all the pushes from the meters through the Zigbee module and sends them to the MQTT server, in this DCU only we have used the Sierra wireless SL8082 module and used open AT firmware) is not able to connect to the server back, we usually remove the sim and insert it back, now the DCU will be able to connect to the MQTT server. But sometimes, though we remove and insert back the same sim in the same DCU, the DCU is not able to connect back to the server. So we have tried to insert a new sim in the DCU and it got connected to the server without any problem. The removed sim is inserted in a different modem, now both the modem and sim are working perfectly fine and the DCU is able to connect to the MQTT server. Because of this, we are unable to find whether the issue is with the modem, code, or sim. If possible, please let us know if there is any possible resolution for this issue. This issue persists for almost all the DCUs
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  1. will you see this if you are using dwl instead of exe?

  2. did you check AT+CREG? and AT+CGREG?

  3. you need to remove some of your code to see if this is code-related problem.

  4. did you check AT+CCLK? to see if the RTC has been reset?

  5. when problem happens, did you check AT+CPIN? ,AT+CREG? and AT+CGREG?

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  1. We are actually using the .dwl file for flashing, not the exe file. We do this using the “download” option through the Developer Studio GUI.

  2. When we get 36 error, that is GPRS setup failure, we executed AT+CREG? and we got 0,1 as a response, which means the sim is inserted and identified by the modem.

  3. What we suspect is, that if it is not coming for all the iterations, then we can take it as a code mistake. Though it persists for some of the iterations alone, do we need to consider it as a firmware issue?

  4. yes, the RTC is perfectly in sync with the time but not all the time, once in a while it does not show the time properly and if we execute the same command again then it shows the proper time. Refer to the image attached.

WhatsApp Image 2024-11-25 at 17.10.24_499c5c6a
WhatsApp Image 2024-11-25 at 17.10.24_499c5c6a551×143 24 KB

  1. Yes we have checked AT+CREG and it shows that sim is inserted. When we give AT+CPIN, we get READY.
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  1. could it be the GUI problem?
    Have you tried AT+WDWL and then download it through x-modem in tera term?

  2. how about AT+CGREG?
    -36 means the GPRS setup failure, probably you need to restart the GPRS connection routine.

  3. you need to remove some of your code to see if this is code-related problem.
    For example, if you just use the sample code without any action after GPRS connected, will you still see this “WIP_BEV_ME_UNREG”

  4. if you need to make sure your RTC is correct, you can implement NTP protocol to the NTP server to check.

  5. when problem happens, can you start the GPRS bearer successfully?
    Are you able to connect to some other TCP/UDP server?

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  1. Now we have tried flashing through the Tera Term XMODEM, and the process is smooth. Though we flashed the dwl file through the download option in Developer Studio GUI, the DCU was not hanging all the time, it was a once-in-a-while case.

  2. When error 36 occurs, we wait approximately 2 minutes because, during this time, the device may connect to the GPRS again. If the device is not able to connect to the GPRS again, then we stop the bearer using wip_bearerStop(b) and ensure that the bearer setup configuration is present through wip_bearerGetOpts and start the bearer using wip_bearerStart(b).

  3. When we usually see this WIP_BEV_ME_UNREG message in the TM console, we remove the sim wait for a few minutes, and again insert it back. Sometimes the device will be connected and in some cases, it will not connect. We repeat this for few times until the device connects. Can you please suggest an alternative way to solve the issue? If possible, please provide the basic code flow to approach.

  5. When this problem happens, the device is able to start the GPRS bearer successfully, but it is not able to make a TCP connection with the MQTT server to send the pushes. During this time we tried checking the ping from the SIM and we are not getting any ping response from the sim.

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  1. then does it work?
  2. you did not isolate if this is coming from your code or something else
  4. are you able to get a IP address? how about restarting the telecom stack by AT+CFUN=0 and AT+CFUN=1? Can this bring the situation back to normal?