Firmware for EMC Funktion Test

[FrankR]

Hi,

we need a firmware for the nRF52840 to do a function test for the EMC approval test.
The test must show that the BT connection still works.
It should also show if the data rate changes when there is EMI.
The software has to be integrated into our test software.

Our customer writes the firmware for the nRF52840 himself.
It is also based on Wirepass and cannot be integrated into our test software.

I had tried the radio test from Nordic.
The software can work as a transmitter or receiver.
But there is no feedback.
The transmitter side cannot determine whether the data has arrived.
The operation of the software is also completely unacceptable for an admission test.

I looked at the software examples and found the ble_app_uart example.
I was able to connect the software to my mobile phone.
However, this application is also completely unacceptable for an EMC approval test.

My desired configuration would be to pair two devices with the ble_app_uart firmware.
Then we would have a serial connection between two devices that are transmitted via BT.
The rest of the adaptation for our test software would not be a problem.

Is it possible to pair two devices with ble_app_uart firmware?

Regards
Frank

[ovrebekk]

Hi Frank

I assume what you are referring to here is the EMC immunity testing. 

Unfortunately this can not be run on dedicated test firmware, it has to be run on the firmware that will be put into the end product. 

For a wireless product you need to be able to establish a link with something (like a smart phone), and see that you can operate the product like normal also when the product is exposed to interference. 

It should also show if the data rate changes when there is EMI.

This should not be a requirement for EMC immunity testing. Is this something that the test facility is asking for?

Best regards
Torbjørn

[FrankR]

Hi Torbjørn,

you don't have to use the software for the final product.
You often can't use it at all because it doesn't have the possibility to show the failure.
If an application communicates very rarely, then no verification can be done.

>>It should also show if the data rate changes when there is EMI.
>This should not be a requirement for EMC immunity testing.
>Is this something that the test facility is asking for?
This feature is required during the RF interference radiation test.

Is it possible to pair two devices with ble_app_uart firmware?

Best Regards
Frank

[ovrebekk]

Hi Frank

FrankR said:

you don't have to use the software for the final product.
You often can't use it at all because it doesn't have the possibility to show the failure.
If an application communicates very rarely, then no verification can be done.

Essentially it is the EN 301 489-17 document that set the requirements. The assessment procedures are defined in chapter 5.3:

And the performance criteria in 6.2 (in your case criteria A would be used):

In the end this is a self declaration, so it is up to you what firmware to put into the device, but the more divergence there is between the test firmware and the actual firmware then the higher the risk that potential issues are not discovered. 

FrankR said:

Is it possible to pair two devices with ble_app_uart firmware?

If you flash two devices with the ble_app_uart and ble_app_uart_c examples then you can have them connect, yes. Pairing (encryption) is not supported out of the box in the ble_app_uart example unfortunately, but I am not sure pairing is what you really need?
Possibly just establishing an unencrypted connection is sufficient?

Best regards
Torbjørn

[FrankR]

Hi Torbjørn,

 >If you flash two devices with the ble_app_uart and ble_app_uart_c examples then you can have them connect, yes.
That sounds good.

I thought pairing meant connecting of two devices to each other.
I don't need the encryption.
What do I have to do so that the two devices connect?

Thanks

Best Regards
Frank

[ovrebekk]

Hi Frank

In Bluetooth terminology 'pairing' is used to describe the process of exchanging encryption keys and enabling encryption, but you can run a Bluetooth connection without pairing if you want. 

If you flash two devices with the ble_app_uart and ble_app_uart_c examples they should connect automatically. The ble_app_uart application starts advertising by default, and the ble_app_uart_c application will look for devices in the area that advertise the Nordic UART service (NUS) and try to connect to them. 

Best regards
Torbjørn