How to use a custom nRF52840 alongside an nRF52840 DK with the DTM module?

RE: How to use a custom nRF52840 alongside an nRF52840 DK with the DTM module?

JONATHAN LL — Tue, 13 Aug 2024 07:53:24 GMT

[quote user="kili"]running the nrfjprog --recover command[/quote]

The recover command wipes the unit and "opens" the device as it disables readback protection.

"Erases all user flash memory and disables the readback protection mechanism if enabled."

[quote user="kili"]Question, before I go into physical modifications of my custom PCB that will be the DUT in this setup (it has an nRF52840 on it). Can I perform the test using:[/quote]

You will need to have access to the TX and RX pin of the DUT. So if you dont have them available you will need to modify the PIN for the sample.

You can use a DK or som other serial to uart converter for communication with the device.

Regards,
Jonathan

RE: How to use a custom nRF52840 alongside an nRF52840 DK with the DTM module?

kenny1389 — Fri, 09 Aug 2024 19:04:25 GMT

Edit: I was able to connect the nRF52840 DK successfully after following the solution in this thread:

nRF Connect for Desktop Bluetooth Low Energy - Keeps on saying "Device must be programmed"

running the nrfjprog --recover command is what allowed me to run the DK with DTM.

Question, before I go into physical modifications of my custom PCB that will be the DUT in this setup (it has an nRF52840 on it). Can I perform the test using:

1. the built in UART/virtual COM port for the DK and
2. CDC ACM implementation on the DUT,

or will I need UART on my custom PCB as well? If so, is it sufficient to only modify the PIN numbers on the direct_test_mode_pca10056 example of the 17.1.0 SDK?

RE: How to use a custom nRF52840 alongside an nRF52840 DK with the DTM module?

kenny1389 — Fri, 09 Aug 2024 16:56:46 GMT

Hi Jonathan, thanks for the reply. I found useful information in the docs you linked; I was able to program a CDC ACM module on my custom board to interface with USB. Looking back at the docs I think I may still need to go for the UART physical connection despite my intention to avoid doing so.

I've run into another issue with my development kit (nRF52840DK) which I will use as the Lower Tester. I tried several ways to program the device, through SES (erasing flash and downloading direct_test_mode_pca10056 firmware onto it) as well as using the nRF Connect Programmer to flash the 10056.hex file on the DK.

However, any time I open the Direct Test Mode module and load the DK, it meets me with

'Device must be programmed, do you want to proceed?'

If I select no, when I initiate the test, it just hangs in the Running device setup:

If I select yes, I get this issue:

I have the DK connected to my PC via USB (J2), the nRF power source switch is set to VDD. Am I missing something, what could be causing the DK to not recognize the correct firmware being on it?

RE: How to use a custom nRF52840 alongside an nRF52840 DK with the DTM module?

JONATHAN LL — Fri, 09 Aug 2024 13:59:33 GMT

Hi,

Use the nRF connect for desktop app, and use the nRF connect SDK, so

https://docs.nordicsemi.com/bundle/ncs-2.5.2/page/nrf/samples/bluetooth/direct_test_mode/README.html

What you would need to to is have to correct pins for uart communication configured on your DUT.

But we have older guides here: https://devzone.nordicsemi.com/nordic/nordic-blog/b/blog/posts/fast-production-screening-based-upon-bluetooth-dtm

And a 3rd party her: https://raytac.blog/2023/11/22/navigating-rf-certification-a-guide-to-dtm-and-radio-testing/ and https://jimmywongiot.com/2021/03/02/rf-physical-test-on-the-nrf5-series/

But I do see that our documentation could maybe be updated here so will have a look.

Feel free to ask if you have any issues or something needs to be clarified.

Regards,
Jonathan