Trying and failing to run the MQTT sample on nRF52840-DK + nRF7002-EK

[__RICHARD__]

Hi,

I have built and run the MQTT sample for an nRF7002-DK and had it work as expected (connect, publish messages to test.mosquitto.org).

Now I'm trying to get that sample to run on an nRF52840-DK with an nRF7002-EK shield. Here's my attempt at the build configuration:

The truncated extra CMake argument says: -DCACHED_CONF_FILE="f:/Ncs_Exercises/mqtt/prj.conf;f:/Ncs_Exercises/mqtt/boards/shell_prj.conf"

And just off the bottom of that screenshot, "Use sysbuild" is unchecked.

As you can see I have borrowed the .overlay file (without really understanding what it is/does) from the Shell sample. The shell_prj.conf file is one I've manually created by copying the contents of the Shell sample's prj.conf. I have previously had the Shell sample building/running as expected on the 52840-DK + 7002-EK combination. I have also pasted the following extra lines into shell_prj.conf:
CONFIG_L2_WIFI_CONNECTIVITY=y
CONFIG_L2_WIFI_CONNECTIVITY_AUTO_CONNECT=n
CONFIG_L2_WIFI_CONNECTIVITY_AUTO_DOWN=n

Connect SDK version is 2.6.1, and I'm using VS Code.

I suspect what I've described above isn't the right way to go about trying to adapt the sample for this hardware, but for better or worse, it does build, run (briefly) and connect to the wifi. It then reliably crashes and reboots, presumably around the time when it actually tries to test.mosquitto.org. But I'm having a tough time finding out exactly where. Printf-style debugging is not getting me there, and when I try to enable CONFIG_MQTT_HELPER_LOG_LEVEL_DBG, it's frustratingly grayed out.

So a few things I'm hoping someone can help me with:

First, is running this sample on the 52840-DK + 7002-EK combination actually possible?

If anyone can describe (or point me to) the right way to try to build an SDK sample (and more specifically this sample) for a non-compatible board, that would be great.

In case I'm approximately on the right track and I'm just missing some config options, I'd obviously like to know what they are.

Thanks,

Richard.

[runsiv]

Hi Richard

I will look into your case. I would just as start note that the 52840 might face memory constrains with using MQTT. As you can see from the Host device consideration the nRF52840 is not recommended for end-device to cloud application, it should work but it is not something we would recommend. 

Just in general I would always recommend if you are new to our wifi stack to go to DevAcademy and have a look at our Wi-Fi Fundamentals course.

As you say it just crashes, could you upload the log from when it crashes? 

I would also like to have your configs including the overlay and prj.conf for the application.

edit: You can test this and see if you see the same behaviormqtt_nrf52840.zip 

Regards

Runar

[__RICHARD__]

Thanks Runar, it'll be 12 hours or so before I can run on the hardware again, I'll get some logs then. But in the meantime I've attached the prj.conf and the shell_prj.conf I mentioned in my first post.5126.prj.conf

shell_prj.conf

[runsiv]

No worries, I would recommend having a look at the projected I upload and test it to see if it behaves the same way on your system

Regards

Runar

[__RICHARD__]

Thanks Runar, I built the contents of the zip you sent, after creating a build configuration for it, and it ran successfully (no crash, connected and sent MQTT messages as expected).

So that's great. I have some questions about the config, but I've run out of time today so will post again soon.

[runsiv]

Sounds good to me, have a great weekend

Runar

[__RICHARD__]

Hi Runar,

I opened a different but related question here:
Can't build MQTT sample for custom board with nrf52840 + nrf7002 via QSPI

If you can possibly take a look that would be great.

[runsiv]

I see Marte has been assigned to the case, so you are in good hands

Regards

Runar