Bluetooth Long Range - Advertising and Connection issues

[Despair1337]

Peripheral: nRF52840 DK
Central: OnePlus 6T, nRF Connect app

I modified ble_app_uart example, to support Bluetooth Long Range:

static void advertising_init(void)
{
    uint32_t               err_code;
    ble_advertising_init_t init;

    memset(&init, 0, sizeof(init));

    init.advdata.name_type          = BLE_ADVDATA_FULL_NAME;
    init.advdata.include_appearance = false;
    init.advdata.flags              = BLE_GAP_ADV_FLAGS_LE_ONLY_LIMITED_DISC_MODE;
    init.config.ble_adv_primary_phy = BLE_GAP_PHY_CODED; // I added this
    init.config.ble_adv_secondary_phy = BLE_GAP_PHY_CODED; // I added this
    init.config.ble_adv_extended_enabled = true; // I added this

    init.advdata.uuids_complete.uuid_cnt = sizeof(m_adv_uuids) / sizeof(m_adv_uuids[0]); // I changed srdata to advdata
    init.advdata.uuids_complete.p_uuids  = m_adv_uuids; // I changed srdata to advdata

    init.config.ble_adv_fast_enabled  = true;
    init.config.ble_adv_fast_interval = APP_ADV_INTERVAL;
    init.config.ble_adv_fast_timeout  = APP_ADV_DURATION;
    init.evt_handler = on_adv_evt;

    err_code = ble_advertising_init(&m_advertising, &init);
    APP_ERROR_CHECK(err_code);
    ble_advertising_conn_cfg_tag_set(&m_advertising, APP_BLE_CONN_CFG_TAG);
}

I observe two issues:

1. Advertising is in short bursts. I measured, that device advertises for 5 seconds, and then 15 seconds delay. Because of this, it's hard to find and connect to device
    (this is long-range)
    (this is normal phy)
2. It's hard to connect. From like 15 tries of connecting, only 4 was successful, after connection, the connection was stable and everything was working correctly

After deleting Long Range code added upper (thus, using normal PHY), everything works perfect.
Any ideas where could be a problem?

Thanks

[Despair1337]

Hi Simonr,

For some reason, when I use desktop nRF Desktop application - Bluetooth Low Energy, it sees only 1M and M2 PHY, Coded PHY advertising devices are not visible.

[Simonr]

Hi again

Right, you're using the nRFConnect for desktop BLE app. This app does not support advertising/scanning on the Coded PHY, as it is based on a version of the S132 SoftDevice. The Dongle supports Coded PHY, but not the firmware the Bluetooth Low Energy app uses.

You need to use the nRFConnect for mobile application and a phone supporting Coded PHY, or a central application scanning using Coded PHY on your Dongle. You can check out this example that a colleague of mine made for the nRF52840. It scans for beacons using extended advertising, so all you should have to do is to set the PHY to Coded PHY and adapt it to fit the Dongle (as explained in our Dongle Programming tutorial here).

ble_app_beacon_scanner_extended.zip

Best regards,

Simon

[Thabet]

HelloSimonr,

Would you have this example using nRF5 SDK 17.0.2? Thanks!

[Simonr]

Hi

Sorry, this is the version we have, but it should not be much work either implementing these changes to this ble_app_beacon_scanner application made for the nRF5 SDK v17.0.2.

7658.ble_app_beacon_scanner.zip

Alternatively you can follow the migration guide to make the existing example compatible with SDK v17.0.2.

Best regards,

Simon