FCC testing with softdevice

[Taavi K]

Hi

I need to certify a product in FCC and they sent us what they want. Radio_test_example is basically what I need, but the problem is that I'm using SoftDevice 110 and can't access NRF_RADIO directly. All I can find in the documentations is how to change the TXPOWER but not the other parameters.

So my question is how to change the other radio parameters (modulation, channel, power etc) with softdevice? 

I need to run nordic in normal mode and thus need to use softdevice (otherwise need to rewrite some of the code).

Any suggestions on how to proceed in this situation?

Thank you in advance

Taavi

[WestCoastDaz]

Taavi K, AmbystomaLabs is right.  We have used radio test example (modified slighty to support our custom PCBAs) to certify 5 products using the nRF52832 over the last 3 years with no problems.  You will normally be required to modify your product to include an SMA connector for the tests and you will need access to the UART to control the test.  It doesn't run with the softdevice so the radio test example has fully control of the radio.  Normally we provide the lab with several samples some running the test firmware and some running application firmware with the softdevice so they can complete all of their testing without having to program PCBAs.

[AmbystomaLabs]

Two thumbs up!!! Nice response.

Similar to you, I did UART and terminal interface during conducted testing. During radiated, I just had 3 versions of radio test (low, mid and high channels) and an SWD programmer. It took less than a minute to reprogram the EUT and put it on a new channel.  Having the 3 wires and laptop computer for a UART connection during radiated proved to be too difficult and it came with its own EMC issues. Though as you did, 3 EUT's could have solved the problem too.

I always make sure to attend testing sessions.  The exposure to the process is invaluable to your career and  you can ensure the technician doesn't make any mistakes. Plus if any problems come up you can fix and reprogram, within the rules, as is necessary to resolve the problem and get the testing back on track.

[Taavi K]

Thank you both for your answers. Will also prepare some different EUT's for them. Is the 'UI' that the radio test example has, enough for them to carry out modulation, power, channel etc tests, or is there something that from your experience should be added? UART communication is not a problem (although it will be through STM). 

Traveling to US is not an option at the moment (too expensive for just these tests), but I agree that it would be good for the future. 

[WestCoastDaz]

Taavi K In my opinion the UI is easy enough to use but you should always create a detailed document that describes your test setup and procedures including photos.  If you have a spectrum analyzer on hand then I recommend running the radio test example to ensure that everything is working before submitting it to the lab.

[Andreas]

Hi,

 

Just as a PS to anyone reading this that might not have a spectrum analyzer available: the RSSI viewer app in nRF Connect for Desktop can also be used (a nRF52 DK is needed to do the measurements) to verify that the test FW is running properly.

 

Best regards,

Andreas

[WestCoastDaz]

Andreas I never thought of using the RSSI tool like that.  I will give that a try next time.  Thanks for the tip!