DMT Test mode (continuous transmission with no modulation on center frequency) / in German: EMV-Testmodus = Dauersenden ohne Modulation auf Mittenfrequez)

[Thomas Friehoff]

Here we go again .... I did read many posts in this forum but did not find an answer.

We need to CE test a small Bluetooth HID keyboard for a special use case.
Our test laboratory is asking us to put the device into the Test-Mode as described in the subject.

Our design is based on a Adafruit ItsyBitsy nRF 52840 running a CircruitPython application.

My question now:
1. Is there any available .UF2 file which can be loaded which is doing nothing else but putting a device in this test mode?
2. Alternatively: We can also put the device into "Arduino-Mode", is there a "Arduino Application" which can put the device into this test mode?
3. Alternatively: Is there any loadable default code which puts the device into this test mode?   

We want to avoid to create a build system which can build and load the Test-Mode app from the nordic SDK.
Reason: A to steep learning curve and effort for a single application.

From what I was reading several people were confronted with the same problem.
And the request are always the same: The certifying lab want's this mode to test "something"....

Thank you for your attention.

Thomas F   

[JONATHAN LL]

Hi Thomas,


We do not have any Arduino code or CircruitPython SW that can put the device in Test-mode, as we at Nordic do not maintain or directly support Arduino. 

Presuming that the test lab wants to test the radio.

We do have two options for Test-mode, the nRF5 SDK or the nRF Connect SDK, both have the Radio test sample and Direct test mode for Bluetooth. 


So usually you would flash the Test application to the device that is tested, then you can flash the existing application back on to the device when testing is done. 


So i would also check with the Arduino forum\support to see if there is a way to load .hex files with the drag and drop feature from their IDE solution. 


If not then you can access the SWD pins on the board, I see that there is to test points on the bottom side of the ItsyBitsy, SWDIO and SWDCLK, these can be used to flash the nrf52840. 




If you want i can make this case private, and you can share pictures or HW files and i can try to provide guidance on how to connect to the device through SWD interface. 

The ItsyBitsy is using a Raytac BLE module. 

Regards,
Jonathan

[Thomas Friehoff]

What a pity !

Arduino is so popular and I think you / Nordic is missing something when not following this trend.

Connecting to the SWD interface is a "pain in the b**!"

- The device needs to be opened.
- There is no real plug where to connect the SWD.
- With a needle adapter is hard to maintain a continuous connection for a longer period of time.

With a programmer/utility which can plug and talk to a USB port, everything will be easier and reproducible for nearly everyone.

I am sure also your support effort will be less if Nordic would publish some easy-to-use Arduino sample code!

It looks to me that this guy in GitHub is almost there...

https://github.com/sandeepmistry/arduino-nRF5

Maybe you can take a look and support him or offer some code samples.

He is talking about being able to access/use the Nordic "Softdevice". 

Am I correct that if this is true, the "Direct Test Mode" sample from the SDK here:

https://infocenter.nordicsemi.com/index.jsp?topic=%2Fcom.nordic.infocenter.sdk5.v15.3.0%2Fble_sdk_app_dtm_serial.html

Would be easy to port?

Could someone at Nordic take a look and try this?

Thank you and best regards

ThomasF

[JONATHAN LL]

Hi Thomas, 

I can see why this is inconvenience but we at Nordic mainly focus on supporting our products and not third party environments. Maybe if enough people request this then it will be something in the future but as for now it is not something we do. So I would check with the Arduino community to see if there is anything there who has experience flashing hex through Arduino or circuit python interface.

There are also many products using the nrf52 series chips that does not have a USB port, but almost all have SWD interface. 


As for the Softdevice, this is closed software so not something that will be available for the public to tinker with.  

Thomas Friehoff said:

There is no real plug where to connect the SWD.

This is because often the development is done on a Development kit, so the final product does not need to be programmed often.

Thomas Friehoff said:

 With a needle adapter is hard to maintain a continuous connection for a longer period of time.

I agree, it does get a bit finicky, more often then not I solder some wires on to the test points and use some jumper wirers to the programmer. 


From what I can understand the UF2 bootloader does not except hex files, 

"The format of the file is a little special. Due to 'operating system woes' you cannot just drag a binary or hex file (trust us, we tried it, it isn't cross-platform compatible)" 


But it looks like it is possible to convert a hex or bin file to UF2,



GitHub - microsoft/uf2: UF2 file format specification 

https://github.com/adafruit/Adafruit_nRF52_Bootloader 


So that might be the way to go for now. 

It is currently Eater vacation in Norway so Tech support staffing will be low, expect delayed replies. Back to normal 19 of April. 

Regards,
Jonathan