LTE cannot be deactivated when +CSCON unsolicited report is enabled

[Siyou]

We tested this issue on serial_lte_modem sample on NCS 1.2 and modem mfw_nrf9160_1.2.0

1, Enable CSCON unsolicited report: 

AT+CSCON=2

2, Activate LTE search and connect to cat-M1 network, device will report "+CEREG: 1,"0001","01A2D001"...."

3, Try to deactivate LTE by command "AT+CFUN=20", it will failed, and the device will hang in here and not accept any AT command more.

Is there any problem for our operations?

[Håkon Alseth]

Hi,

 

Could you post the log you're seeing? I tried this with slm, and I am unable to get the AT+CFUN=20 to fail, unless I already have taken down the link, in which it returns "<err> at_host: Could not send AT command to modem: -8"

 

Kind regards,

Håkon

[Siyou]

Hi

I can reporduce this issue by following commands:

[14:00:17.411]Ready
[14:00:26.897]AT%XSYSTEMMODE?
[14:00:26.906]%XSYSTEMMODE: 1,0,1,0
OK
[14:00:32.648]AT+CGMR
[14:00:32.658]mfw_nrf9160_1.2.0
OK
[14:00:40.393]AT%XBANDLOCK=2,"1000000000010010001"
[14:00:40.405]OK
[14:00:45.873]AT+CSCON=2
[14:00:45.882]OK
[14:01:32.657]at+cereg=5
[14:01:32.667]OK
[14:01:36.706]AT+CFUN=21
[14:01:36.745]OK
[14:01:37.957]+CEREG: 2,"0001","01A2D101",7,0,0,"11100000","11100000"
[14:01:38.128]+CSCON: 1,7
[14:01:38.229]+CEREG: 1,"0001","01A2D101",7,,,"11100000","11100000"
[14:01:40.499]+CSCON: 0,7
[14:01:52.913]AT+CFUN=20
[14:01:59.377]AT+CFUN?
[14:02:06.041]AT+CEREG?

And, the log will show nothing during the whole test:

*** Booting Zephyr OS build v2.1.99-ncs1-1141-g616c7d5becd4  ***

[00:00:00.307,373] <inf> app: Serial LTE Modem

[Håkon Alseth]

Hi,

 

Thank you for providing the sequence.

I can confirm that I see this when using AT commands in serial_lte_modem. 

 

Could you try applying this pull-request? https://github.com/nrfconnect/sdk-nrf/pull/2264

 

You can generate a .diff by adding .diff to the URL (in this case: https://github.com/nrfconnect/sdk-nrf/pull/2264.diff), then saving this in the ncs/nrf folder and writing:

cd path/to/ncs/nrf
git apply 2264.diff

 

(an alternative and more in-depth "git way" of checking out a PR locally can also be found here: https://help.github.com/en/github/collaborating-with-issues-and-pull-requests/checking-out-pull-requests-locally)

 

A precompiled .hex for the nRF9160-DK with the above PR included is also posted by a colleague of mine in this thread:

https://devzone.nordicsemi.com/f/nordic-q-a/60724/issue-in-serial-lte-modem-v22-04/250589#250589

 

Kind regards,

Håkon

[Siyou]

Thanks for your sharing, it works with your patch.