nrf9160 modem not working after executing 2 AT Commands.

RE: nrf9160 modem not working after executing 2 AT Commands.

J0sh1101 — Mon, 26 Jun 2023 13:16:34 GMT

Hi,

Sorry for the late reply. I'm working on a few projects, then I switch from one to another, and this then takes time.

[quote userid="90815" url="~/f/nordic-q-a/101045/nrf9160-modem-not-working-after-executing-2-at-commands/432360"]Great to hear that it is working.[/quote]

Thanks!:D

[quote userid="90815" url="~/f/nordic-q-a/101045/nrf9160-modem-not-working-after-executing-2-at-commands/432360"]Are you able to reproduce the condition?[/quote]

I tried a few times and could not reproduce the problem. I think the problem was not with the AT commands but with the modem firmware version. At that time I also updated the firmware version.

[quote userid="90815" url="~/f/nordic-q-a/101045/nrf9160-modem-not-working-after-executing-2-at-commands/432360"]I notice that you are using the release candidate, nRF Connect SDK v2.3.0-rc1, does the issue occur if you try nRF Connect SDK v2.3.0?[/quote]

I was trying with both the SDKs (v3.3.0 and v2.3.0-rc1), and got the same result as explained in my previous post above. Both SDKs are compatible with modem version v1.3.5.

However, when I use the modem version v1.3.5, then I need to add the nrf_modem_lib_init() function, otherwise it does not work.

I will close this ticket as my problem is resolved.

Thanks for the help!

RE: nrf9160 modem not working after executing 2 AT Commands.

helsing — Wed, 21 Jun 2023 13:34:38 GMT

[quote user="J0sh1101"]I managed to get the application working again[/quote]

Great to hear that it is working.

[quote user="J0sh1101"]but I don't know what exactly triggered this problem.[/quote]

Are you able to reproduce the condition?

[quote user="J0sh1101"]Does this mean that minor modem updates are not backward compatible? [/quote]

Each new modem firmware is tested with a few versions of nRF Connect SDK. Please consult the modem firmware compatibility matrix. Both mfw v1.3.4 and v1.3.5 should be compatible with nRF Connect SDK v2.3.0.

I notice that you are using the release candidate, nRF Connect SDK v2.3.0-rc1, does the issue occur if you try nRF Connect SDK v2.3.0?

RE: nrf9160 modem not working after executing 2 AT Commands.

J0sh1101 — Wed, 21 Jun 2023 10:29:13 GMT

Hey,

I managed to get the application working again, but I don't know what exactly triggered this problem.

Was it the combination of AT commands or the SW modem update from 1.3.4 to 1.3.5. I remember now that I updated the modem SW to the latest version. In the new modem SW update, there is a slightly different approach to initializing the modem. Below you can see the two AT client applications. One was created a few months ago and one now:

Difference: The nrf_modem_lib_init() was added and the order of the code was modified a bit.

When I updated the modem to 13.5 and added the function nrf_modem_lib_init(), everything worked again.

Does this mean that minor modem updates are not backward compatible?

Because...

I tried to test the modem SW 1.3.5 without the nrf_modem_lib_init() function and it did not work. If I revert to 1.3.4, then the nrf_modem_lib_init() function is not needed.

Thanks for the answear.