RSSI Measurement in Nordic N52840

[shaktis]

I have n52840 chip, for Tx power measurement, I have used nRF connect for desktop v.4.2.1.

I used Direct test mode and in Transmitter tab using single channel mode. I have used used UART to set up connection with desktop and the chip.

In DTM mode we can able to transmit the power from the chip, that can be measured using at the other end with help of spectrum analyzer.

But to check received power I tried using RSSI viewer, but when I tried to connect the chip using UART it show " No pre-compiled firmware is available for the selected device"; "Error while setting up device" and "No device setup found"

My question is during DTM mode the connection with UART is established while during RSSI its shows Error messages?

What could be the reason and how to overcome?

Is there any way to measure received power in the nordic chip n52840?

[runsiv]

Hi, 

Please see this thread, 

Regards

Runar

[shaktis]

Thanks Runar

The problem is when we connect and do measurements using nrf connect and Direct Test mode the device is connected and do the transmission measurement but when we open RSSI viewer for the dame device it shows Error: No pre-compiled firmware is available for the selected device"; "Error while setting up device" and "No device setup found".

The chip is connected using UART

What could be the reason and how to resolve this??

Thanks in advance

[Eugene Yu]

Hi,

Are you using 2 custom boards? one for DTM and the other for RSSI viewer?
Using 1 board, it is not possible to run both DTM and the RSSI viewer.

To measure the RSSI, you should run 2 boards as below figure.

(Left side is DTM, Right side is RSSI viewer)

and the prebuilt firmware is only applicable to the nRF5x development kits.

It might be possible to run your own board with this GitHub firmware example which is running with RSSI viewer but I never tried it before...

I recommend you test with our DK first.

This might help you to understand how it works.

Tx test with RSSI viewer · olleheugene/nRF-DTM Wiki (github.com)

[shaktis]

Hi Eugene Yu

Thanks for the reply.

Yes, get to know from your comment that for RSSI measurements we need to have two separate boards, on is acting as a TX and using DTM mode and the second one is used for RSSI viewer to check RSSi levels.

But the thing is that when I connect my custom board with desktop and open RSSI viewer it shows error messages: No pre-compiled firmware is available for the selected device"; "Error while setting up device" and "No device setup found".

How to resolve this error, then only the device will work.

I connected board and desktop using UART, in direct test method mode connection is established with no issues but in RSSI viewer app it shows the above error messages.

shakti

[Eugene Yu]

Have you tried to make your own firmware that is based on the code that I shared in reply?

Even if you used your own RSSI viewer firmware,

Try to use DK such as nRF52-DK, nRF52840-DK, and nRF52833-DK.

It seems to doesn't work other than Nordic DK.

[runsiv]

Hi Shakti

The only supported boards if you are using the RSSI viewer app is PCA10040, PCA10056 and PCA10059. In other words you can't use your custom boards unfortunately. I would recommend checking out the solution I posted in my first reply. 

Regards

Runar

[shaktis]

Hi Runar

So , If some one is using n52840 chip to some specific application and using it we can't measure that device received power using RSSI viewer app in desktop and and making connection with UART?

[runsiv]

Hi, That is correct, for measuring RX I would reefer to this whitepaper. It described how to do a RF Performance Test, if you only want a indication I would make the DUT send the received RSSI over UART and store the data. 

Regards

Runar

[shaktis]

Hi

How can we transfer received RSSI over UART and store the data?

For the measurement setup , we could use any arbitrary Continuous wave generator to act as source?

And the receiver end would be the Our Nordic chip connected With Laptop through UART and we can able to see received Power?

[runsiv]

Hi, 

For the RSSI I would again reefer to the my initial post as they use the same example and discuss how to get the RSSI value. As for how to store the data is a bit up to your preferences. For Windows I like the tera term terminal and it has a option to store the terminal session values as a text file. Many terminals has this option, it is also possible to just mark the data from the terminal you wish to store and copy paste it into another document. 

As for the wave generator. It needs to have modulated carrier with the correct modulation and a valid data package. The easiest solution is to use the "low cost" setup described in the white paper with a calibrated RF attenuator between a nRF52840 DK and your custom board.   

I would recommend using the Radio Test Example, on the custom board, change the UART pins in the overlay to the UART pins in your custom board. 

Regards

Runar