Direct Test Mode v2.4.1 GUI does not work with third party boards

[lx_brz]

Using nRF Connect for Desktop on Ubuntu 24.04 LTS I am trying to use the Direct Test Mode v2.4.1 software with our own custom board.

On https://docs.nordicsemi.com/bundle/nrf-connect-direct-test-mode/page/index.html you wrote:

> The application also supports third-party devices that are programmed with the DTM standard protocol and expose access to it through a serial port.

But it is not possible. Trying to select the FTDI based UART and running clicking "Start test" I see the following error:

At the same time I am connected to the board via RTT to view logs and don't see any communication.

On the contrast when I use cutecom to send commands as hex codes directly, everything works as expected:

And I see the expected communication activity on the RTT logs:

Help would be much appreciated. It would be much more convenient to use your GUI based Direct Test Mode tool instead of sending and decoding the DTM commands as hex manually.

There are no problems by the way using a nrf52840DK. It only does not work with the custom board, connected via UART, although you explicitly write:

> The application also supports third-party devices that are programmed with the DTM standard protocol and expose access to it through a serial port.

Thanks

Alex

[Charlie]

Hi Alex,

Just have some questions about your setup:

Is your custom board also use nRF52840 or other chip? Is it also running Bluetooth: Direct Test Mode (nordicsemi.com) sample?

When you test DTM with nRF52840DK, do you use uart through onboard interface MCU or just usb port?

Best regards,

Charlie

[lx_brz]

Charlie said:

Is your custom board also use nRF52840 or other chip?

Yes

Charlie said:

Is it also running Bluetooth: Direct Test Mode (nordicsemi.com) sample?

Yes

That both doesn't matter though, it rather seems that the nordic Direct Test Mode application does not even try to start communication.

Charlie said:

When you test DTM with nRF52840DK, do you use uart through onboard interface MCU or just usb port?

I'm plugging in the board where the connector is labelled "MCU USB", so it should be "uart through onboard interface MCU". The nordic Direct Test Mode application device selector then looks like this:

[Elfving]

Hello Alex, I'll be taking over this case for a sec as Charlie is currently busy.

So first of all I just wanted to mention that we do not officially support for nRF Connect for Desktop on Ubuntu 24, but that hopefully won't be a real issue in this case.

lx_brz said:

This seems to work without problems. Using it I can start transmitter tests and see the communication happening in RTT logs.

So I assume you mean that this project works on the third party board using the GUI that comes with it, but does it work with the nRF Connect for Desktop DTM app?

But it is not possible. Trying to select the FTDI based UART and running clicking "Start test" I see the following error:

Could you try pressing the button for "programming compatible fw" there in the GUI? Or is maybe the problem that you don't want it to work with just nordics FW, but any DTM fw?

lx_brz said:

That both doesn't matter though, it rather seems that the nordic Direct Test Mode application does not even try to start communication.

I believe it checks for compatible fw before doing anything else.

Regards,

Elfving

[lx_brz]

Elfving said:

So first of all I just wanted to mention that we do not officially support for nRF Connect for Desktop on Ubuntu 24, but that hopefully won't be a real issue in this case.

I'm aware of this and asked a colleague with a mac to try it. The result is the same.

Elfving said:

So I assume you mean that this project works on the third party board using the GUI that comes with it, but does it work with the nRF Connect for Desktop DTM app?

Exactly.

Elfving said:

Could you try pressing the button for "programming compatible fw" there in the GUI?

There is no programmer attached, only the serial connection, so there is no point in trying to press that button.

Elfving said:

Or is maybe the problem that you don't want it to work with just nordics FW, but any DTM fw?

Not sure what exactly you mean with "any DTM fw", but I have programmed the custom board with this sample: docs.nordicsemi.com/.../README.html