RF testing. AT commands not recognized for GPS and XRFTEST

[CRD]

We are currently getting our firmware ready to test devices for FCC and other radio testing.

We have an AThost-like setup that passes AT commands from a terminal over a BLE connection. The firmware then passes those commands internally to nrf_modem_at_cmd_async()

This works great for normal AT commands like AT+CFUN, AT+CREG etc... However we need to do calls to AT%XRFTEST for GNSS and AT#XGPS but I always get immediate ERROR response. Is there a config to allow these extra NRF specific AT commands? Or do I need to filter them and send them to a different function?

I'm at a loss and can't figure out why this will not work. We have not called XPRODDONE on this device.

[Mariano Goluboff]

Hi Colin,

The commands with AT% should work, since these are Nordic-specific commands in the modem. Are you escaping the percentage sign in the formatted string? It should be `%%`.

The AT# commands are specific to Serial LTE Modem (SLM). That only runs on the application processor if you have compiled it as part of your application. Are you using SLM?

[CRD]

YES! Thank you that was it. I passed the value as "AT%%XRFTEST" and now it works! Thank you!

I see... we are not using SLM. The main value I'm trying to get is the C/N0 which the testing facility has asked for. Are there any other ways I could read or calculate this from AT commands? I was hoping to be able to accomplish most of our testing through the AT command terminal if possible.

[Mariano Goluboff]

Take a look at this exercise in the Developer Academy:

https://academy.nordicsemi.com/courses/cellular-iot-fundamentals/lessons/lesson-6-cellular-fundamentals/topic/lesson-6-exercise-1/

In step 15 it describes how to get the carrier-to-noise density ratio for the satellites that the GNSS receiver is currently tracking.

Mariano