About SDK15.3 scan filter condition selection problem

[June6]

I have a project that needs to scan and filter the advertising name, uuid and mac address from the device. I will set them one by one and enable them one by one. I set them one by one, and then enable them one by one, at this time, the slaves are normally scanned. Then I tried to change the filter to NRF_BLE_SCAN_ALL_FILTER and changed the following parameters to false, they can still be scanned. Once nrf_ble_scan_filters_enable is used to select the filter condition as NRF_BLE_SCAN_ALL_FILTER and the following parameters are changed to true, the slave device can no longer be scanned. And scaning event is NRF_BLE_SCAN_EVT_NOT_FOUND. So how to solve this problem？

/**@brief Function for handling Scanning Module events.
 */
static void scan_evt_handler(scan_evt_t const * p_scan_evt)
{
    ret_code_t err_code;
	
    switch(p_scan_evt->scan_evt_id)
    {
         case NRF_BLE_SCAN_EVT_CONNECTING_ERROR:
         {
              err_code = p_scan_evt->params.connecting_err.err_code;
              APP_ERROR_CHECK(err_code);
         } break;

         case NRF_BLE_SCAN_EVT_CONNECTED:
         {
              ble_gap_evt_connected_t const * p_connected =
                               p_scan_evt->params.connected.p_connected;
             // Scan is automatically stopped by the connection.
             NRF_LOG_INFO("Connecting to target %02x%02x%02x%02x%02x%02x",
                      p_connected->peer_addr.addr[0],
                      p_connected->peer_addr.addr[1],
                      p_connected->peer_addr.addr[2],
                      p_connected->peer_addr.addr[3],
                      p_connected->peer_addr.addr[4],
                      p_connected->peer_addr.addr[5]
                      );
         } break;

         case NRF_BLE_SCAN_EVT_SCAN_TIMEOUT:
         {
             NRF_LOG_INFO("Scan timed out.");
             scan_start();
         } break;
				 
		 case NRF_BLE_SCAN_EVT_NOT_FOUND:
		 {
				 NRF_LOG_INFO("Scan not found.");
		 } break;
				 
         default:
             break;
    }
}


/**@brief Function for initializing the scanning and setting the filters.
 */
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;

    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_NAME_FILTER, m_target_periph_name);
    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_filter_set(&m_scan, SCAN_ADDR_FILTER, &m_target_periph_addr.addr);
    APP_ERROR_CHECK(err_code);
	
    err_code = nrf_ble_scan_filters_enable(&m_scan, NRF_BLE_SCAN_ALL_FILTER, true);
    APP_ERROR_CHECK(err_code);
		
//    err_code = nrf_ble_scan_filters_enable(&m_scan, NRF_BLE_SCAN_NAME_FILTER, false);
//    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);
	
//    err_code = nrf_ble_scan_filters_enable(&m_scan, NRF_BLE_SCAN_ADDR_FILTER, false);
//    APP_ERROR_CHECK(err_code);
}

Hope to get a reply.
June6

[a93radon]

Hello,

I am facing this problem as well in SDK 15.2 and am looking for a solution. I want to implement scanning for UART with filtering for UUID and name. For me, the nrf_ble_scan_filters_enable function with the NRF_BLE_SCAN_ALL_FILTER and true parameters works in the ble_app_hrs_c example when scanning for HRS, but it does not work for UART. Scanning for UUID or name individually does behave as expected, however. What could be the cause of this, and how can I filter both UUID and name when scanning for the UART service?

[Amanda Hsieh]

Hi a93radon, 

     Sorry for the delay. I am just back into the office. In the ble_app_uart_c, it could filter for UUID. Could you try the example without modification? If you still have the problem, please create a new support case and refer to this case. Thanks. 

-Amanda Hsieh

[a93radon]

Thank you for the response. For clarification, filtering for specifically UUID works properly in the example and in my code, as does filtering specifically for name. The problem arises when I filter for both simultaneously using the NRF_BLE_SCAN_ALL_FILTER parameter in the  nrf_ble_scan_filters_enable function.

[awneil]

a93radon said:

The problem arises when I filter for both simultaneously

According to this post:

https://devzone.nordicsemi.com/f/nordic-q-a/49146/get-device-name-from-filter-match-event/195750#195750

the name is part of the advertising data, but the uuid is part of the scan response data.

that may explain why you can't filter on both at once ... ?

[a93radon]

Thanks, it looks like this was the issue. When I put both the name and the uuid in the advertising data packet, I am able to match the filter as expected.

However, this is still not ideal because the uuid bytes take up the majority of the space in the packet, leaving me with space for only two letters for the name. I have tried to use extended packet (i.e. set extended = 1 in scan params and set NRF_BLE_SCAN_BUFFER to 255 in sdk_config) but it does not seem to work. Do you have any advice for this?

[Amanda Hsieh]

Please create a new support case for your question. Thanks. 

-Amanda H.

[a93radon]

Was able to resolve this on my own - for me, the extended advertising works on SDK 15.3 but not on 15.2.