DTM UART communication through USB port instead of Tx Rx

[Hadi Deknache]

Hi everyone!

I am currently working on a custom prototype that is using the nrf52840 chip and sdk 15, and now want to perform DTM tests on the device. Looking at the DTM example code and description, I see that the application uses 2 pins (tx,rx) in order to perform the UART communication. In my case with the custom prototype board that is not possible since we have not included these pins. Is there any other way to perform the UART communication through the USB port instead. One idea that I am currently thinking of is to implement USB CDC and use that instead, does it sound reasonable and/or are there any other easier way to do that?

Would be very thankful for any help I can get!

/Hadi

[Wojtek]

I think the easiest solution is just to set other pins as UART rx/tx, as choice is flexible, as long as you have some GPIO available on your board.

[Hadi Deknache]

Hi Wojtek, thanks for your help. The problem is that I am trying to avoid any changes on the HW and do not want to solder additional pins on the custom board. Therefore, looking for a solution where I could make use of the NRF USB J3 port instead, since it is available already

[Hadi Deknache]

UPDATE: I have started implementing USB cdc in the DTM example that is available, however, I am facing some problems. When I run my code on the board I can't see any com port appearing. So my question is: Does the USB CDC example require a Softdevice to be programmed on the device in order for the device to work with USB cdc? If so, then I assume that it won't work to integrate both cdc and DTM, since, the DTM application requires that no softdevice is present on the device. Correct me if I am wrong

[ovrebekk]

Hi Hadi

Neither the USBD CDC example nor the DTM example uses the SoftDevice, so I doubt this is the cause of the problem. 

I actually did this exercise a while back and was able to merge the USBD_CDC and the DTM examples into one. Unfortunately it was over a year ago, and the example is based on SDK v14.2.0...

Still I have added it for reference. With some luck you can find some use for it, just use it at your own risk ;)

usbd_cdc_dtm.zip

Best regards
Torbjørn

[Hadi Deknache]

Thanks for the help Torbjørn, I really appreciate it. I have one question regarding the DTM tests. We are going to perform certification test soon: Radio (TX: Mod low,mid,high and carrier & RX: no beacon ) and also EMC with usb traffic, my question is whether it is possible to perform this with the DTM application only or do I also have to use the Radio application?