Test mode

[Shalom Gerbi]

Hi 

We are currently in the midst of our production process and are utilizing a microcontroller that communicates with a BLE chip.
As part of our quality assurance, we aim to test the Tx mode and the Rx sensitivity using UART.

To proceed with this, we require guidance on the specific commands that need to be sent to the BLE chip to initiate the test mode.
Could you please provide us with the following information:

• The exact commands to send from the MCU to the BLE to start the Tx and Rx tests.
• The pattern of data that should be transmitted for the Tx test.
• The methodology for measuring Rx sensitivity.

[ketiljo]

The best approach is to use DTM and a Bluetooth tester here, unless you can do a automated test setup in Labview for instance.

DTM can be found here: https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/samples/bluetooth/direct_test_mode/README.html

[Shalom Gerbi]

Thank you. I have reviewed this document, but I'm finding it difficult to understand what we should do if we want to test it. I only see the commands listed.

As I explained earlier, we want to test it in production by sending commands over the UART and getting back the results. Let me clarify:

We have a controller that manages all the BLE activity, and we want to test the transmission chain. Specifically, we want to:

1. Send a command over the UART.
2. Connect the antenna to a power meter or spectrum analyzer to measure the output power.
3. Test the sensitivity by sending a signal to the antenna and receiving back the BER (Bit Error Rate).

From this document, I am having trouble understanding which commands to send and in what order. Could you please provide more detailed instructions or examples?

[ketiljo]

DTM uses a defined command set over UART. You can find the details in the Bluetooth Corespec. https://www.bluetooth.com/specifications/core-html/ volume 6, part F

It's meant only to be used by a Bluetooth tester. If you don't have that, you can use radio test instead: https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/samples/peripheral/radio_test/README.html

Testing sensitiivity isn't straigth forward here. If you use a nRF devices (a DK) as the tester (TX) you can use the command "start_tx_modulated_carrier" and the number of packets (e.g. 1500) and count the number of received packets on DUT. You can then calculate the PER (packet error rate). 

Maybe you can use a fixed level in a production test and just verify that PER is ok, compared with a golden sample. 

 

[Shalom Gerbi]

I still find it difficult to understand how to test this in production. Do you have a detailed Protocols API? The document is very messy and does not explain the process clearly. It doesn't specify the order of steps, what is needed, or how to proceed.

[ketiljo]

Do you have a Bluetooth tester you intend to use in production? What equipment and instuments do you plan to use?

[Shalom Gerbi]

1. Measuring the output power via spectrum.
2. Receiving packet error information.

These commands will be sent over UART from my controller,

Could you please provide the steps to enter BLE test mode

[ketiljo]

For DTM, see the Bluetooth Core spec. There are no better info. 

For radio test, see https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/samples/peripheral/radio_test/README.html

Do you have a Bluetooth tester you intend to use in production? What equipment and instuments do you plan to use?