nRF Connect log

[Karthiknk]

Hi,

I'm testing heart rate measurement example with my nRF52 DK. In the nRF connect application, I see the logs are converted from Hexadecimal value to user-readable values. I want to implement this in my own project with accelerometer values. In the accelerometer project, I only see values in hexadecimal. Thank you for your time and information. 

[Simonr]

Hi

The error code 0x07 points towards you using an invalid parameter in you GATT request. Have you edited the db_disc_handler to handler custom service discoveries rather than the heart rate and battery services used by default?

Best regards,

Simon

[Karthiknk]

Yes, I did. 

static void db_disc_handler(ble_db_discovery_evt_t * p_evt)
{
ble_acl_on_db_disc_evt(&m_acl_c, p_evt);
}

I followed this tutorial How to build the simple nrf52 BLE central. I will attach the code blocks of  service initialisation and database discovery event below, please check them.

uint32_t ble_acl_c_init(ble_acl_c_t * p_ble_acl_c, ble_acl_c_init_t * p_ble_acl_c_init)
{
    VERIFY_PARAM_NOT_NULL(p_ble_acl_c);
    VERIFY_PARAM_NOT_NULL(p_ble_acl_c_init);
    VERIFY_PARAM_NOT_NULL(p_ble_acl_c_init->evt_handler);

    uint32_t      err_code;
    ble_uuid_t    acl_uuid;
    ble_uuid128_t acl_service_base_uuid = {BLE_UUID_OUR_BASE_UUID};

    acl_uuid.type = p_ble_acl_c->uuid_type;
    acl_uuid.uuid = BLE_UUID_OUR_SERVICE;

    p_ble_acl_c->evt_handler                 = p_ble_acl_c_init->evt_handler;
    p_ble_acl_c->error_handler               = p_ble_acl_c_init->error_handler;
    p_ble_acl_c->p_gatt_queue                = p_ble_acl_c_init->p_gatt_queue;
    p_ble_acl_c->conn_handle                 = BLE_CONN_HANDLE_INVALID;
    p_ble_acl_c->peer_acl_db.acl_cccd_handle = BLE_GATT_HANDLE_INVALID;
    p_ble_acl_c->peer_acl_db.acl_handle      = BLE_GATT_HANDLE_INVALID;

    err_code = sd_ble_uuid_vs_add(&acl_service_base_uuid, &p_ble_acl_c->uuid_type);
    if (err_code != NRF_SUCCESS)
    {
        return err_code;
    }
    VERIFY_SUCCESS(err_code);
    
    return ble_db_discovery_evt_register(&acl_uuid);
}

void ble_acl_on_db_disc_evt(ble_acl_c_t * p_ble_acl_c, const ble_db_discovery_evt_t * p_evt)
{
    // Check if the Heart Rate Service was discovered.
    if (p_evt->evt_type == BLE_DB_DISCOVERY_COMPLETE &&
        p_evt->params.discovered_db.srv_uuid.uuid == BLE_UUID_OUR_SERVICE &&
        p_evt->params.discovered_db.srv_uuid.type == p_ble_acl_c->uuid_type)
    {
        // Find the CCCD Handle of the Heart Rate Measurement characteristic.
        uint32_t i;

        ble_acl_c_evt_t evt;

        evt.evt_type    = BLE_ACL_C_EVT_DISCOVERY_COMPLETE;
        evt.conn_handle = p_evt->conn_handle;


        for (uint32_t i = 0; i < p_evt->params.discovered_db.char_count; i++)
        {
            const ble_gatt_db_char_t * p_char = &(p_evt->params.discovered_db.charateristics[i]);
            switch (p_char->characteristic.uuid.uuid)
            {
                case BLE_UUID_OUR_CHARACTERISTC_UUID:
                    evt.params.peer_db.acl_cccd_handle = p_char->cccd_handle;
                    evt.params.peer_db.acl_handle      = p_char->characteristic.handle_value;
                    break;
                default:
                    break;
            }
        }

        NRF_LOG_DEBUG("Accelerometer Service discovered at peer.");
        //If the instance has been assigned prior to db_discovery, assign the db_handles.
        if (p_ble_acl_c->conn_handle != BLE_CONN_HANDLE_INVALID)
        {
            if (p_ble_acl_c->peer_acl_db.acl_handle == BLE_GATT_HANDLE_INVALID)
            {
                p_ble_acl_c->peer_acl_db = evt.params.peer_db;
            }
        }

        p_ble_acl_c->evt_handler(p_ble_acl_c, &evt);
    }
}

If you need additional details, I can give you. And one more question, while programming our own service in peripheral, we mention the UUID is vendor-specific using BLE_UUID_TYPE_VENDOR_BEGIN, but in central, the tutorial didn't mention it anywhere. I doubt if that could be the problem. 

Thank you.

[Karthiknk]

Karthiknk said:

<debug> ble_db_disc: Starting discovery of service with UUID 0xABCD on connection handle 0x0

From my error message, I can see the central is looking for service with UUID 0xABCD. Also to make sure, my peripheral is also advertising 128-bit base UUID with service ABCE in it. 

I don't understand what is creating the error.

Karthiknk said:

<error> nrf_ble_gq: SD GATT procedure (2) failed on connection handle 0 with error: 0x00000007.

[Karthiknk]

Problem fixed. The service declaration in central and peripheral were bit different, I changed it. Now it can connects and identify the service.

<info> app: Connected.
<debug> nrf_ble_gq: Registering connection handle: 0x0000
<debug> ble_db_disc: Starting discovery of service with UUID 0xABCD on connection handle 0x0.
<debug> nrf_ble_gq: Adding item to the request queue
<debug> nrf_ble_gq: GATTC Primary Services Discovery Request
<debug> nrf_ble_gq: SD is currently busy. The GATT request procedure will be attempted again later.
<debug> nrf_ble_gq: Processing the request queue...
<debug> nrf_ble_gq: GATTC Primary Service Discovery Request
<debug> nrf_ble_gq: SD is currently busy. The GATT request procedure will be attempted again later.
<debug> nrf_sdh_ble: BLE event: 0x3A.
<debug> nrf_ble_gatt: ATT MTU updated to 23 bytes on connection 0x0 (response).
<info> app: GATT ATT MTU on connection 0x0 changed to 23.
<debug> nrf_ble_gq: Processing the request queue...
<debug> nrf_ble_gq: GATTC Primary Service Discovery Request
<debug> nrf_ble_gq: SD GATT procedure (2) succeeded on connection handle: 0.
<debug> nrf_sdh_ble: BLE event: 0x24.
<debug> nrf_ble_gatt: Data length updated to 27 on connection 0x0.
<debug> nrf_ble_gatt: max_rx_octets: 27
<debug> nrf_ble_gatt: max_tx_octets: 27
<debug> nrf_ble_gatt: max_rx_time: 2120
<debug> nrf_ble_gatt: max_tx_time: 2120
<info> app: Data length for connection 0x0 updated to 27.
<debug> nrf_sdh_ble: BLE event: 0x30.
<debug> ble_db_disc: Found service UUID 0xABCD.
<debug> nrf_ble_gq: Adding item to the request queue
<debug> nrf_ble_gq: GATTC Characteristic Discovery Request
<debug> nrf_ble_gq: SD GATT procedure (3) succeeded on connection handle: 0.
<debug> nrf_ble_gq: Processing the request queue...
<debug> nrf_sdh_ble: BLE event: 0x32.
<debug> nrf_ble_gq: Adding item to the request queue
<debug> nrf_ble_gq: GATTC Characteristic Discovery Request
<debug> nrf_ble_gq: SD GATT procedure (3) succeeded on connection handle: 0.
<debug> nrf_ble_gq: Processing the request queue...
<debug> nrf_sdh_ble: BLE event: 0x32.
<debug> nrf_ble_gq: Adding item to the request queue
<debug> nrf_ble_gq: GATTC Characteristic Descriptor Request
<debug> nrf_ble_gq: SD GATT procedure (4) succeeded on connection handle: 0.
<debug> nrf_ble_gq: Processing the request queue...

But still, I can not see the data. Can you suggest what could possibly be the problem?