nrf52832 direct test mode

[Tanu]

Hello

I am using a Nrf52832 kit from Murata japan distributor.(https://wireless.murata.com/mbn52832.html)

My purpose is to be able to perform DTM on above mentioned kit. I am using two of above mentioned kit and nrf connect DTM tool.

My Os is windows 10

below are my questions and queries:

1.For programming my kit, Do i just need to program it using precomplied hex file available in nrf52sdk.I have tried programming using DTM sample code from following:

https://www.nordicsemi.com/Software-and-tools/Software/nRF5-SDK

or 

https://github.com/NordicSemiconductor/pc-nrfconnect-dtm

I got to know online that it doesnt need softdevice, so i have not programmed that in my kit.

• Do i need to program bootloader in case of DTM test?

2. The DTM performed by apps like nrf connect tool or nrfgo studio or using a certified tester (Anritsu MT8852 tester),

• are all method same?
• can i test all the below properties from any of these methods?

(

• Transmission power and receiver sensitivity
• Frequency offset and drift
• Modulation characteristics
• Packet error rate
• Intermodulation performance

)

3.I saw production test using DTM

1. is it also DTM test?
2. is it different from the one that is done using nrf connect dtm or other tools?
3. Are there different types of DTM?

4. I have been trying to test dtm proceudres explained in following website

https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/samples/bluetooth/direct_test_mode/README.html

I used follwing methods

1. Testing with another development kit
2. Testing with nRF Connect for Desktop

when using the first method, i only get to know the number of received packets:

• can you please guide me to perform the complete test using the same method?

when using the later method(nrf connect tool), i see following problems

when i select my device, i get the following log(image)

I proceed to perform my dtm, starting the receiver mode and as i start my dtm test,(Start Test button) , My screen goes blank and white.

i refresh the nrf connect but then the connection is lost.

• How can i solve this issue of my nrf connect going blank?

If there is any other method or tool that i should use to perform DTM on my kit, please guide me. My end goal is to be able to perform complete DTM test on my kit.

Thanks,

[Kenneth]

Do i need to program bootloader in case of DTM test?

There is no need for bootloader of softdevice no, only the DTM hex file is sufficient. However if you have used other GPIO's for your module than the nRF52-DK use for UART (DTM), then you may need to re-compile the project for your module by modifying the pins used for UART:
https://infocenter.nordicsemi.com/topic/sdk_nrf5_v17.0.2/ble_sdk_app_dtm_serial.html 

2. The DTM performed by apps like nrf connect tool or nrfgo studio or using a certified tester (Anritsu MT8852 tester),

• are all method same?
• can i test all the below properties from any of these methods?

The DTM test firmware is the same, and the commands are the same, however the nordic tools can only display simple packet error rate, while the Anritsu can display much more information (e.g. modulation, offset, drift etc).

You can refer to Bluetooth specifications (e.g. Core_v5.0.pdf) Volume 6, Part F, Direct Test Mode on serial interface commands, events and test packet contents:
https://www.bluetooth.org/docman/handlers/DownloadDoc.ashx?doc_id=421043

I proceed to perform my dtm, starting the receiver mode and as i start my dtm test,(Start Test button) , My screen goes blank and white.

i refresh the nrf connect but then the connection is lost.

• How can i solve this issue of my nrf connect going blank?

I suggest to try a restart of your computer, make sure that you have installed the latest nrf command line tools, and that the only application you have open is the nRF Connect for Desktop. You will need to open 2 windows of Direct Test Mode, one to act as a receiver, the other as transmitter.

It may be a good idea to first run tests on two nRF52-DK before you start with your own hardware.

[Tanu]

Thanks for answering.I was able to perfrom DTM using nrfgo studio and nrf connect tool (both). However, they mainly show me the packets received. my question is as below:

• How can I get to check PER and the number of packets transmitted on any one of above tools?

I have some more queries:

I wish to be able to perform more tests to get more informations, for that I have been thinking to using the nrfDK kit as lower tester as mentioned in nAN 34 document.In the production test mentioned in nAN 34 document, using nRF8001‑DK）or（nRF51822‑DK, 

• Can i use my same nrf52832 kit in place of above mentioned kits ? 
• Could I test for more information using below method as compared to nrf connect tool?(more than number of packets received and PER)
• Is there a limitation of what I can test using below method ?(as explained in nAN 34 document)

• Can i use two nrf52832 kits instead of the above mentioned circuit? is it necessary to use attenuator?
• in case attenuator and sma is important to use, which attenuator and sma should i use?
• how to know the pin and connection details of that circuit?

[Kenneth]

Don't think PER is displayed in nrfgo studio and nrf connect tools. You can use or modify the python script that is part of nAN-34 to calculate PER. Please refer also to the rf test spec by Bluetooth (chapter 6.4) on how to calculate PER:
https://www.bluetooth.org/docman/handlers/DownloadDoc.ashx?doc_id=225827 

The interval between each packet depends on the packet length and on-air modulation, see BT Core Specification v. 5.2, vol 6, part F, section 4.1.6:
https://www.bluetooth.com/specifications/specs/core-specification/ 

So to calculate PER you will need measure the time between start and stop receive test, and then based on the transmit interval you can find the number of packets transmitted during that period and compare with the number of packets received to find PER.

You can use nRF52-DK yes, but you will need a proper Anritsu tester if you want to measure anything more than packet error rate. I recommend to get attenuators during testing, so you can also verify that matching components and antenna are working.

Kenneth

[Tanu]

Thanks for answering.

Please tell me which attenuator to use for testing my nrf52832 kits, as i have searched evrywhere and i cant decide which one to use. Please tell me the specific one, its urgent. Thanks

[Kenneth]

I don't know which one we are using, but you want something like this ( you want to get a few of each value so you can put them in series):
https://www.passion-radio.com/sma/sma-attenuator-826.html

Kenneth