RE: How to compare the peripheral device adresses and connect from the UART string

Einar Thorsrud — Mon, 08 Apr 2019 12:58:09 GMT

Hi,

You can modify the NUS central example to connect to a specific address for instance by changing the scan_init() function to this:

static void scan_init(void)
{
    ret_code_t          err_code;
    nrf_ble_scan_init_t init_scan;
    static uint8_t      addr[BLE_GAP_ADDR_LEN] = {0x45, 0x9F, 0xC7, 0xF7, 0x66, 0xEF};

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

    init_scan.connect_if_match = true;
    init_scan.conn_cfg_tag     = APP_BLE_CONN_CFG_TAG;

    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_ADDR_FILTER, addr);
    APP_ERROR_CHECK(err_code);

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

You also have to modify sdk_config.h, setting NRF_BLE_SCAN_ADDRESS_CNT to 1. This will only connect to a device with BLE MAC address EF:66:F7:C7:9F:45.

The mechanism is the same if you get the address via UART instead, and then you can update the filter as needed by using nrf_ble_scan_all_filter_remove() to remove an old address and set a new filter. ( In fact the filtering mechanism is quite flexible, but that should not be relevant here. If you are interested, just look at the API documentation in <SDK>\components\ble\nrf_ble_scan\nrf_ble_scan.h