UUID scan

[Juniorprogrammer]

Hi,

I do have a question about the ble_app_uart for central device. Now it is set to make connection with the periheral based on the UUID. I can't find where in the software this is set. Can someone help me out?

Because now if I'm changing the device name I can't get connected. Am I able to change the connecting UUID?

Kind regards,

JP

[Joakim Jakobsen]

Hi! 

Could you share which version of the SDK you are working with? 

Br, 
Joakim

[Joakim Jakobsen]

From the information in the question I assume you are working with the nRF5 SDK? Correct me if I'm mistaken. 

The following code are copied from the ble_app_uart_c example in the nRF5 SDK v.17.1.0: 

/**@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_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);

From scan_init() you can see that the scan filter are set (using nrf_ble_scan_filter_set). SCAN_UUID_FILTER is selected and a pointer to the NUS UUID. 

Br, 
Joakim

[Juniorprogrammer]

Thank you Joakim,

Yes you’re right I’m working with the nRF5 SDK.

I find this also but wasn’t sure if it is what I’ searching for. So the SCAN_UUID_FILTER includes the UUID of the peripheral device?

Kind regards,

JP

[Joakim Jakobsen]

No problem!

Juniorprogrammer said:

SCAN_UUID_FILTER includes the UUID of the peripheral device?

Not quite. The SCAN_UUID_FILTER just defined the type of filter, i.e an UUID-filter. The "&m_nus_uuid" points to the actual UUID to use when filtering.

Br, 
Joakim 

[Juniorprogrammer]

So if I'm right, if I make a change in the UUID on the peripheral. I have to make changes in the  m_nus_uuid on the central device?

[Joakim Jakobsen]

If you are using scan filter (UUID) on the central device, you will have to match the UUID of the peripheral, yes. 

Br,
Joakim