nRF9160 Connectivity issue

[dhandzic]

We have designed a board using the nRF9160 SiP and LWM2M. When testing with poor network connection (~  -118dB) we experience a strange behaviour. From monitoring the current profile it looks like the device is in DRX mode but it is no longer registered at the server. We have eDRX turned of and Registration Lifetime set to 90s. Not sure if this question is for Nordic or Telia, I will ask both.

Best regards

Dirk

[Øyvind]

Hi Dirk, 

Can you provide an output from AT client, which shows more information about the connection? Also, it may be required that you also do modem trace.

Kind regards,
Øyvind

[dhandzic]

Hi Öyvind,

I am running a LWM2M client application. I dont think the AT client will replicate this behaviour. I am not sure how to get a modem trace while using our LWM2M application.

Best regards

Dirk

[Øyvind]

How are you connecting the UART ports to your computer? Do they show up in your Device Manager (as COM ports)?

What is the unreadable text that is shown in LTE Link Monitor? What device are you connecting when you see this?

-Øyvind

[dhandzic]

I am using a FTDI TTL-232R-3V3 cable. It shows up in the Device Manager, I am able to connect to this VCOM port using LTE Link Monitor, but the port does not show up in Trace Collector!

When connecting with LTE Link Monitor to this port the output looks like this:

Best regards

Dirk

[dhandzic]

Carl Richard Steen Fosse at Nordic has both one of our boards and a cable. I can share my board definition files and the project files if this helps.

I think there might be an issue with latest version of the Trace Collector and the FTDI cable.

Best regards

Dirk

[Øyvind]

Dirk, I've discussed this issue with Carl Richard and we were not able to get it working. The output in LTE Link Monitor looks like the modem trace data, but needs to be verified. It looks like your settings for the trace collector is configured incorrectly. Can you please see this thread about a similar issue, and see if this fixes the issue. Make sure that your cable supports 1Mbaud as the modem trace is hard coded to this, you also need to confirm that your configured correct UART for modem trace.

[dhandzic]

Hi Öyvind,

the FTDI TTL-232R-3V3 is pecified to support up to 3 Mbaud. I have also been able to use this cable and LTE Link Monitor to see LOG_INFO output from the board.

In LTE Link Monitor the FTDI cable shows up regardless if it is connected to the board or not. In Trace Collector it does not show up at all. I have checked the trace_uart_init function in bsd_os.c and it it points to the UART1 which also is used and is working for LOG_INFO outputs. Is there maybe a conflict? Do I need to change the trace output UART to UART2?

Best regards

Dirk

[Øyvind]

Hi Dirk, 
Thanks for verifying the information. Yes, it sounds like you should change the UART output of the trace. Please change it to UART2.

Kind regards,
Øyvind

[dhandzic]

Hi Öyvind,

I have changed the uart in bsd_os.c to uart2 but the problem is still the same. Trace Collector shows "No device available" and after a while the screen turns white. A couple of weeks ago there has been a similar problem with the LTE Link Monitor. I think it is the same bug when the app has to talk to a non DK board. The FTDI cables are usually no problem.

Best regards

Dirk

[Øyvind]

Can you please share your current project with me? 

Thanks!

Kind regards,
Øyvind

[dhandzic]

Q3IoT_zephyr_boards_arm.zip

Q3IoT210121.zip

Hi Öyvind,

here are my board def files and the entire project map.

Best regards

Dirk

[Øyvind]

When connecting to LTE Link Monitor with your device, can you please screenshot what shows in Window? Please screenshot the whole LTE Link Monitor window.