nRF52840 DK change scanning PHY to Coded Phy

[CraigE]

I'm trying to test long range beacons with coded phy on the nrf52840 dongle, so I've set out to turn my nrf52840 DK into a beacon scanner that will spit out data over uart.

I've started with the ble_app_uart_c example and added the BLE_GAP_EVT_ADV_REPORT to the ble_evt_handler to pick them up.

I'm running into trouble actually changing to a coded phy for scanning, and the application seems to crash when I set the init_scan.p_scan_param.

static ble_gap_scan_params_t const m_scan_param_coded_phy =
{
    .extended       = 1,
    .active        = 0x01,
    .interval      = BLE_GAP_SCAN_INTERVAL_MIN,
    .window        = 10,
    .timeout       = 0x0000, // No timeout.
    .scan_phys     = BLE_GAP_PHY_CODED, 
    .filter_policy = BLE_GAP_SCAN_FP_ACCEPT_ALL,
};


static void scan_init(void)
{
    ret_code_t          err_code;
    nrf_ble_scan_init_t init_scan;

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

    init_scan.connect_if_match = true;
    init_scan.conn_cfg_tag     = APP_BLE_CONN_CFG_TAG;
    
    init_scan.p_scan_param = &m_scan_param_coded_phy; // My addition

    err_code = nrf_ble_scan_init(&m_scan, &init_scan, scan_evt_handler);
    APP_ERROR_CHECK(err_code);

    err_code = nrf_ble_scan_filter_set(&m_scan, SCAN_UUID_FILTER, &m_nus_uuid);
    APP_ERROR_CHECK(err_code);

    err_code = nrf_ble_scan_filters_enable(&m_scan, NRF_BLE_SCAN_UUID_FILTER, false);
    APP_ERROR_CHECK(err_code);
}

Not sure what's going on here at all, or if I'm at all doing the right thing!

[Simonr]

Hi Craig

When scanning using CODED_PHY, you need to enable the extended bit when scanning, as well as set the NRF_BLE_SCAN_BUFFER to BLE_GAP_SCAN_BUFFER_EXTENDED_MIN (which is 255). Please try setting the scan buffer to the correct value. If that doesn't work, please check out this thread which describes what scan parameters to look out for, and what the parameters mean. 

Best regards,

Simon

[CraigE]

I'm struggling to see where this is supposed to slot into this particular example. It seems like all the examples are written in a different way so it's quite hard to keep track!

[Simonr]

Hi Craig

The NRF_BLE_SCAN_BUFFER is set in the sdk_config.h file, if that's what you're struggling with.

Best regards,

Simon