Direct test mode sample crashes when using LE coded PHY

[basvkesteren]

Hi,

I'm playing around with the Bleutooth DTM sample (https://github.com/nrfconnect/sdk-nrf/tree/master/samples/bluetooth/direct_test_mode) on two nRF52840 boards. The documentation only mentions nRF53 support, but the code seems to have nRF52 support, so i figured i'd give it a try

So far it seems to work when using LE 1 Mbps and 2Mbps. However, when using one of the coded PHY's, the receiving board crashes (actually, it just reboots..) as soon as it receives something.

Is this a known limitation?

Thanks,

-Bastiaan

[Simonr]

basvkesteren said:

I think integrating the nRF5 code into that would be tricky due to the different API's and such...

Indeed.

basvkesteren said:

If I disable the assert-check in nrfx_timer_enable(), the code runs. Dunno what I'm breaking by doing that, though

 Erratum 172 refers to BLE long range co-channel performance in the nRF52840 where you can experience packet loss when a blocker signal is present at the same or a nearby RF frequency. The consequence here is that the BLE test with co-channel interference (RF-PHY/RCV/BV-29-C) will fail without the correct FW workaround.

It seems like this workaround might not be implemented correctly in NCS as of yet. I will report this internally and come back to you with any updates on this. Thank you for updating us with your discoveries. I can't guarantee that this will be prioritized and fixed immediately though, as we already have a functioning DTM example in the nRF5 SDK, but it should find its way into an NCS release eventually.

Best regards,

Simon