nRF9160, often reboots or ERROR after AT#XCELLPOS=2

[Stas Jis]

We use nRF9160 with our board (with Serial LTE Modem 1.9.1).
We recently started using AT#XCELLPOS=2 instead of AT#XCELLPOS=1 after that we often get into trouble with the nRF board.
Sometimes we see that nRF transmits to us "Ready" after this command or transmits ERROR many times.
And if nRF started to send ERROR, it happened without stopping.
And only reboot nRF helped in this case.

I attached the AT command sequence that we execute.
First option:

AT+CEREG=5

OK

AT+CFUN?

+CFUN: 1
OK

AT+CEREG?

+CEREG: 5,5,"084D","00A52803",7,,,"11100000","11100000"
OK

AT#XNRFCLOUD?

#XNRFCLOUD: 1,0,16842753,"50334e33-3135-4235-80b9-291bef027f41"

OK

AT%NCELLMEAS

OK

%NCELLMEAS: 0,"00A52803","42507","084D",12,1600,498,59,21,38247,35053

AT#XCELLPOS=2

Ready

Second option:

AT+CEREG=5

OK

AT+CFUN?

+CFUN: 1
OK

AT+CEREG?

+CEREG: 5,5,"084D","00A52803",7,,,"11100000","11100000"
OK

AT#XNRFCLOUD?

#XNRFCLOUD: 1,0,16842753,"50334e33-3135-4235-80b9-291bef027f41"

OK

AT%NCELLMEAS

OK

%NCELLMEAS: 0,"00A52803","42507","084D",3,1600,498,60,14,38047,34868

AT#XCELLPOS=2

OK

ERROR

ERROR

ERROR

ERROR

ERROR

ERROR

We didn't have these problems when we just use AT#XCELLPOS=1.

[Didrik Rokhaug]

Hi,

Have you tried NCS v2.1.0, to see if you get the same errors there?

Also, could you provide the log from the application (which is sent over RTT by default)?

In the case where you get the "ready" message, you might need to add CONFIG_RESET_ON_FATAL_ERROR=n as well.

Best regards,

Didrik

[Stas Jis]

Hi Didrik,
You wrote about  NCS v2.1.0, do you mean SDK 2.1.0 for SLM firmware?

What will happen if we reset this definition (CONFIG_RESET_ON_FATAL_ERROR=n) ? Does the nRF module continue to work or require a reboot?

[Didrik Rokhaug]

Stas Jis said:

You wrote about  NCS v2.1.0, do you mean SDK 2.1.0 for SLM firmware?

Yes, the SLM application in version 2.1.0 of the nRF Connect SDK.

Note that cellular positioning is disabled by default.

Stas Jis said:

What will happen if we reset this definition (CONFIG_RESET_ON_FATAL_ERROR=n) ? Does the nRF module continue to work or require a reboot?

You need to add it to the prj.conf file in the SLM project. You then need to re-build the project, and flash the nRF9160 again.

The config option will change the behaviour of the fault handler, so that it will not reset the device in case a fault happens. This allows us to get more logs out of the device in case of a fault, but you will then have to reset the device manually to get it back to a working state again.

---

I have also tried to reproduce it myself, and it does indeed look like the SLM is crashing in 1.9.1. However, I am not able to reproduce it with 2.1.0.

[Stas Jis]

Hi Didrik,
We returned by the previous logic work with CELLPOS=1, and sometimes we have the same problem with nRF reset (it's happening much more seldom, but it's repeated):

AT+CEREG=5

OK

AT+CFUN?

+CFUN: 1
OK


AT+CEREG?

+CEREG: 5,5,"1D6B","001B6A02",7,,,"11100000","11100000"
OK

AT#XNRFCLOUD?

#XNRFCLOUD: 1,0,16842753,"50345835-3035-4060-802a-240d25e0f94e"
OK

AT#XCELLPOS=1

Ready

[Didrik Rokhaug]

Which SDK version are you using?

Do you get the crashes on 2.1.x also?