Scanning filter fail

[Nguyen Trong Tuan]

Hello everyone,

I'm programming for nRF52833, using SDK17. When I program for scanning filter (SCAN_NAME_FILTER and SCAN_UUID_FILTER) and debug, I got these errors. I don't know where these errors came from. Can anyone help me with this??

Here is my code and my errors.

Hope for your reply as soon as possible!!

Thanks

Best regards,

static ble_uuid_t const m_nus_uuid =
{
    .uuid = BLE_UUID_NUS_SERVICE,
    .type = NUS_SERVICE_UUID_TYPE
};


static char const m_target_periph_name[] = "BLE_DEMO_24"; 

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_params;


    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_filters_enable(&m_scan, NRF_BLE_SCAN_NAME_FILTER | NRF_BLE_SCAN_UUID_FILTER, false);
    APP_ERROR_CHECK(err_code);

}

[Einar Thorsrud]

Hi,

The error code is 0x12 which is NRF_ERROR_CONN_COUNT, so most likely you have configured too few connections in sdk_config.h. What is the value of NRF_SDH_BLE_TOTAL_LINK_COUNT and NRF_SDH_BLE_CENTRAL_LINK_COUNT? Assuming you should ave one connection, both needs to be (at least) 1. Note that if you increase this number you also need to reserve more RAM to the SoftDevice.

[Nguyen Trong Tuan]

Hi,

tks for your reply and I really sorry about my late reply. Really sorry about that. 

The I let the value of NRF_SDH_BLE_CENTRAL_LINK_COUNT = 0; and NRF_SDH_BLE_TOTAL_LINK_COUNT = 1;

So should I increase them???

[Einar Thorsrud]

Hi,

As you write, this code is not modified, and it still has the ob ious error that you have configured NRF_SDH_BLE_CENTRAL_LINK_COUNT to 0, when it should be (at least 1). And increasing it, you will have to adjust the application RAM start address, to make more room for the SoftDevice. That should fix the issue with scanning. I am not sure what else you want me to look for?

[Nguyen Trong Tuan]

It's so hard for me to find the appropriate one for my application. Are there shortcut to find this number??

[Einar Thorsrud]

Hi,

You need to set this number in your application's sdk_config.h file. If you only have one central role at a time, then you set NRF_SDH_BLE_CENTRAL_LINK_COUNT to 1. You can se a higher number if you like. The only problem is that the SoftDevice will need more RAM in this case, but it is not a problem unless your device is RAM constrained.

As mentioned before you need to update the application RAM start address and size when doing this. just enable debug logging and do as instructed in the log (see here for more details about adjusting RAM start address/size based on SoftDevice configuration.)

[Nguyen Trong Tuan]

Oh many tks. I forget to set NRF_SDH_BLE_CENTRAL_LINK_COUNT to 1. 1 more question before I close this topic. What is the meaning of NRF_SDH_BLE_CENTRAL_LINK_COUNT?? 

[Einar Thorsrud]

That is how many concurrent central links + scanner/observer you can have. So if you just need to scan, then you can set this to 1. If you need to scan or have an active connection as a central role you can also set this to one. If you for instance need to maintain 3 connections while scanning, you set this to 4, etc. Remember that you typically also need to increase NRF_SDH_BLE_TOTAL_LINK_COUNT when increasing NRF_SDH_BLE_CENTRAL_LINK_COUNT.

[Nguyen Trong Tuan]

Okay tks. I get your point. Thank you for your support!!