BLE DTM Test functionality of Nordic zephyr BLE controller not working

[djgj]

Hello, 

I am using NCS 1.7.0 for our latest product development based on nRF5340.

We have previously used Open source zephyr project for our development. We have an application which we use for certification purposes. This application basically uses underneath BLE DTM test functions: https://github.com/zephyrproject-rtos/zephyr/blob/main/subsys/bluetooth/controller/ll_sw/nordic/lll/lll_test.c

Now for our new product we are using NCS 1.7.0 version as of now and also using zephyr BLE controller provided in NCS. We want to reuse our certification application which uses lll_test functions. But unfortunately it is not working on nRF5340 as expected.

We are facing problem where ll_test_tx works only for maximum 1 second (or even less) and after that i don't see any RF signals in the analyzer. There seems to some timing issue when using DTM test functions on nRF5340. I searched in open source zephyr project for any clues and i found these:

https://github.com/zephyrproject-rtos/zephyr/issues/42534

https://github.com/zephyrproject-rtos/zephyr/pull/42866

* Does anyone know what is causing this issue onnRF53?

* Is there a chance that these can be fixed in NCS? 

* Does `/samples/peripheral/radio_test` work with NCS zephyr BLE controller?

We are currently blocked by this to certify our devices. Kindly provide a solution for this problem.

Regards,

DJ

[Hung Bui]

Hi DJ, 

I'm checking internally to see if we have a solution for you. I will keep you updated. 

Regarding your question about the radio_test sample, as far as I know it uses the radio directly so it doesn't matter if your firmware will use Zephyr controller or Softdevice controller. 

Which certification are you planning to do ? If you are certifying your hardware I don't think it's important if you run on Zephyr controller or Softdevice controller or bare metal . For example the direct_test_mode sample also use radio in bare metal. 

[djgj]

Hi, 

    Thank you for the response.

We are certifying our hardware. Our certification application targets executing Tx and Rx on BLE Channels with or without modulation.

We basically used the functions from here:  https://github.com/zephyrproject-rtos/zephyr/blob/main/subsys/bluetooth/controller/ll_sw/nordic/lll/lll_test.c

Can you also kindly tell me which sample is closer to using lll_test.c from original zephyr repo?

*  `/samples/peripheral/radio_test` 

*  `/samples/bluetooth/direct_test_mode` 

Regards,

DJ

[Hung Bui]

Hi DJ, 

If you are testing with a Bluetooth Tester equipment (Anritsu MT8852 or R&S CBT32 etc), then the direct test mode firmware should be used. It follows the Direct Test Mode protocol defined in Bluetooth Spec. 

If you are testing anything else, FCC for example, then the radio test would be a better option. In the radio test you have the flexibility to configure what you want to transmit. 

The Direct test mode example and the lll_test.c should behave very similar, as far as I know. 

[djgj]

Hi,

   Thank you very much for the response. I will take a look at those examples.

Meanwhile i will wait for answers on my other questions on solving the issue in lll_test.c itself.

Regards,

DJ

[Hung Bui]

Hi DJ, 

The update will come directly to the Github PR and issue report that you pointed to. It's the same staffs that I reported to.