Unmodulated TX Carrier and softdevice

[Elias Löwe]

Hi!

Is it technically possible to implement performing of unmodulated TX carrier transmission by a write to some BLE characteristic? If yes, then from what to start?

Thank you!

[cbd]

I guess that you could, as all DTM, radio test functions are available from with the SDK, but you wouldn't be able to receive any BLE communications after doing so.

[Elias Löwe]

I've tried this procedure in my project

    NRF_RADIO->SHORTS          = 0;
    NRF_RADIO->EVENTS_DISABLED = 0;
    NRF_RADIO->TASKS_DISABLE = 1;

    while (NRF_RADIO->EVENTS_DISABLED == 0)
    {
        // Do nothing.
    }
    NRF_RADIO->EVENTS_DISABLED = 0;

    // prepare radio
    NRF_RADIO->SHORTS  = RADIO_SHORTS_READY_START_Msk;
    NRF_RADIO->TXPOWER = (tx_power << RADIO_TXPOWER_TXPOWER_Pos);
    NRF_RADIO->MODE    = (mode << RADIO_MODE_MODE_Pos);

    // set channel
    NRF_RADIO->FREQUENCY = channel;

    // begin
    NRF_RADIO->TASKS_TXEN = 1;

But getting to a breakpoint with empty call stack in ozone.

If I execute only this in a main function, then it somehow works, though currently I don't have anything to analyze if it was transmitted or not.

[cbd]

Have a look at the nRF SDK Radio Test Example.

It may be that you can configure a DevKit to detect the unmodulated carrier, although I've not tried it myself.

[Elias Löwe]

Yes, I went through this example but it has softdevice disabled.

[cbd]

Yes.

I don't think that you can do what you wish with the SoftDevice enabled.

You'll need to react to data received either through a custom characteristic or over the Nordic BLE UART code, then disable the softdevice to run the radio test code.

I tend to check a gpio line on power-up and switch to my DTM code before SoftDevice start-up. You could check an NVM location to do the same and then after a period erase that NVM location and trigger a reset.