Default values for Periodic TAU, Active Timer, eDRX cycle time and Paging Time Window that Asset Tracker V2 uses.

[JackW]

We're in the process of developing an nRF9160-based product that will use Asset Tracker V2.  We're building out the firmware and one of the things we'd like set or change are the default values for the eDRX and PSM timers.

I've been going through the Asset Tracker V2 source code that's on Github.  I've found several Kconfig files that have the defult values for several data module, the modem module and the cloud module, but none of these have default values for the PSM of eDRX timer values.

Can someone please point me to the right files?

Thanks

[Michal]

Hello,

The correct file for Kconfig settings is prj.conf. This is where you should add your own configuration if needed.

There you can find the following:

## Power saving timers.
### 320 hours PSM.
CONFIG_LTE_PSM_REQ_RPTAU="11000001"
### 20 seconds active time.
CONFIG_LTE_PSM_REQ_RAT="00001010"

The eDRX is not defined in there, so it uses the default values. You can look them up for example via our Kconfig search.

If you are new to NCS and nRF9160, I would highly recommend looking at our courses on DevAcademy, specifically those two:

nRF Connect SDK Fundamentals

Cellular IoT Fundamentals

Best regards,

Michal

[JackW]

Thank you very much Michal!  Exactly what I was looking for.

Yeah, I knew what the default settings were because I could use the appropriate AT commands to query them.  I just didn't know where they were set in the Asset Tracker code.  Now, thanks to you, I do,

Also, good to know that the eDRX timers are set to the default values otherwise I would have been searching for that in the code too. 

[Michal]

You're welcome!

I understand that there is quite a lot to learn with Zephyr and especially LTE as well.

Another trick is that when you compile your project, there will be a .config file in build/zephyr/ where you can see all the Kconfig values actually used in compilation.

You can also access it inside the nRF Connect for VS Code tab:

Best regards,

Michal