Time out error while production test using DTM

[Cimteker]

Hello,

I am testing 9 channels for PER (1,2,3,21,22,23,37,38,39). During testing the last 3 channels I always get a single time out error in response to LE_TEST_END. I also get much higher PER for higher channels (not sure if these 2 problems are related). Anybody with a similar experience? I am using nRF51 dev kit.

Thanks

Jerry

[Edvin]

Hello,

 

During testing the last 3 channels I always get a single time out error in response to LE_TEST_END

 So that is channels 37,38 and 39?

 

I also get much higher PER for higher channels

 And this is 21, 22, 23?

What environment are you testing in? Do you have an RF shielded box, as described in section 3.2 here?

Can you also describe your test setup? Do you use a DK, or an external tester? (MT8852B)

[Cimteker]

Maybe a picture of our dev board will help. It's pretty old, the system was sitting idle for almost 2 years.

[Edvin]

Hello,

Can you test DK->DK, to see whether the issue is with the DK that you are using or if it actually is the DUT that is acting weird. 

What I find strange is that 37-39 is getting a lower power, as these frequencies aren't even in the same place (which you can see here).

But it may be that the antenna would require some tuning.

Could you test DK->DK and see if it behaves the same? This would suggest that it is actually the DK that you use for testing that is acting weird.

Best regards,

Edvin

[Cimteker]

Thanks Edvin,

Can I do DK->DK test with just one DK? Would I use nRFStudio for this?

[Edvin]

You would need the same setup as you have now, with the DK that you already use as a tester, and another DK programmed with the DTM example from the SDK as a Device Under Test.

The device that you tested on until now is a custom PCB, right?

Best regards,

Edvin

[Cimteker]

Right, but I do not have another DK.

[Edvin]

Cimteker said:

Right, but I do not have another DK.

 How many packets are you sending per channel? Can you try to increase it to something like a 1000 packets per channel? And you are probably also generating a report that you are looking at. Can you send the report from a test after you increased the number of packets?

Best regards,

Edvin

[Cimteker]

Thanks Edvin. The timeout issue is gone once I changed the test time to 1000 ms.

I am still dealing with infrequent failures. I even implemented retries but when it fails, it fails 3 times in a row. I am not sure what could be causing this, my DUT is in a shielded RF box so it cannot be an external interference.