creating custom service and characteristics with different Base UUID : connecting and discovering

RE: creating custom service and characteristics with different Base UUID : connecting and discovering

Kenneth — Wed, 02 Jun 2021 16:09:21 GMT

The ble_nus_c_on_db_disc_evt() was not designed to handle your UUID configuration no. So you would need to re-write the code to handle your setup, unfortunately I don't have time to do this for you, but it should be doable if you understand that you need 2 of these if statements:

if (p_evt->evt_type == BLE_DB_DISCOVERY_COMPLETE &&
p_evt->params.discovered_db.srv_uuid.uuid == BLE_UUID_NUS_SERVICE &&
p_evt->params.discovered_db.srv_uuid.type == p_ble_nus_c->uuid_type)

Because even if BLE_UUID_NUS_TX_CHARACTERISTIC and BLE_UUID_NUS_RX_CHARACTERISTIC share the same value, they don't have the same uuid_type.

Kenneth

RE: creating custom service and characteristics with different Base UUID : connecting and discovering

MokhlesAdalia — Wed, 02 Jun 2021 14:57:44 GMT

Hi Mr kenneth,

i think you didn't get my question and i wasn't able to explain.

my central nrf51 is able to doscover/connect and send messages to the othe BLE device.

the problem is that i can't receive messages.

it is beacuse as mentionned :

#define BLE_UUID_NUS_SERVICE 0x5343 .
#define BLE_UUID_NUS_TX_CHARACTERISTIC 0x5343
#define BLE_UUID_NUS_RX_CHARACTERISTIC 0x5343

BLE_UUID_NUS_TX_CHARACTERISTIC and BLE_UUID_NUS_RX_CHARACTERISTIC shares the same value which will make a problem in the function below in ble_nus_c.c ( i made my modification in ble_nus_c.c / ble_nus_c.h).

void ble_nus_c_on_db_disc_evt(ble_nus_c_t * p_ble_nus_c, ble_db_discovery_evt_t * p_evt)
{
    ble_nus_c_evt_t nus_c_evt;
    memset(&nus_c_evt,0,sizeof(ble_nus_c_evt_t));

    ble_gatt_db_char_t * p_chars = p_evt->params.discovered_db.charateristics;

    // Check if the NUS was discovered.
    if (p_evt->evt_type == BLE_DB_DISCOVERY_COMPLETE &&
        p_evt->params.discovered_db.srv_uuid.uuid == BLE_UUID_NUS_SERVICE &&
        p_evt->params.discovered_db.srv_uuid.type == p_ble_nus_c->uuid_type)
    {

        uint32_t i;

        for (i = 0; i < p_evt->params.discovered_db.char_count; i++)
        {
            switch (p_chars[i].characteristic.uuid.uuid)
            {
							
							case BLE_UUID_NUS_TX_CHARACTERISTIC:
                    nus_c_evt.handles.nus_tx_handle = p_chars[i].characteristic.handle_value;
                    break;

                case BLE_UUID_NUS_RX_CHARACTERISTIC:
                    nus_c_evt.handles.nus_rx_handle = p_chars[i].characteristic.handle_value;
                    nus_c_evt.handles.nus_rx_cccd_handle = p_chars[i].cccd_handle;
                    break;

                default:
                    break;
							
            }
        }
        if (p_ble_nus_c->evt_handler != NULL)
        {
            nus_c_evt.conn_handle = p_evt->conn_handle;
            nus_c_evt.evt_type    = BLE_NUS_C_EVT_DISCOVERY_COMPLETE;
            p_ble_nus_c->evt_handler(p_ble_nus_c, &nus_c_evt);
        }
    }
}

having the same value (0x5343) will make a problem in this switch case!

RE: creating custom service and characteristics with different Base UUID : connecting and discovering

Kenneth — Tue, 01 Jun 2021 20:40:37 GMT

You are calling sd_ble_uuid_vs_add() several times, but you don't really store away the unique uart_uuid.type that you will get every time you call sd_ble_uuid_vs_add(), instead you just overwrite it? That won't work, you need to buffer in a variable the uart_uuid.type, so you can use it when you later add the characteristic or service you want to create.

If you call sd_ble_uuid_vs_add() 3 times, then you will receive 3 unique uart_uuid.type. When later for instance call sd_ble_gatts_service_add(), then make sure to use the uart_uuid.type that returned when you added the sd_ble_uuid_vs_add() for the service.

Kenneth

RE: creating custom service and characteristics with different Base UUID : connecting and discovering

MokhlesAdalia — Mon, 31 May 2021 14:03:28 GMT

can someone help please!

RE: creating custom service and characteristics with different Base UUID : connecting and discovering

MokhlesAdalia — Thu, 27 May 2021 12:53:59 GMT

Hi,

Yeah, all of that was done, i think you didn't get what i mean exactly,

in ble_nus_c.c i added that :

uint32_t ble_nus_c_init(ble_nus_c_t * p_ble_nus_c, ble_nus_c_init_t * p_ble_nus_c_init)
{
	
    ble_uuid_t    uart_uuid;
    ble_uuid128_t nus_base_uuid = NUS_BASE_UUID;
	
    ble_uuid128_t char1_base_uuid = CHAR1_BASE_UUID;
    ble_uuid128_t char2_base_uuid = CHAR2_BASE_UUID;
	
    VERIFY_PARAM_NOT_NULL(p_ble_nus_c);
    VERIFY_PARAM_NOT_NULL(p_ble_nus_c_init);


    err2 = sd_ble_uuid_vs_add(&char1_base_uuid, &p_ble_nus_c->uuid_type);
    //VERIFY_SUCCESS(err_code);
		APP_ERROR_CHECK (err2);
		uart_uuid.type = p_ble_nus_c->uuid_type;
    uart_uuid.uuid = BLE_UUID_NUS_TX_CHARACTERISTIC;

    err3 = sd_ble_uuid_vs_add(&char2_base_uuid, &p_ble_nus_c->uuid_type);
    //VERIFY_SUCCESS(err3);
		APP_ERROR_CHECK (err3);
		//printf("error_code = %d\n",err3);
    uart_uuid.type = p_ble_nus_c->uuid_type;
    uart_uuid.uuid = BLE_UUID_NUS_RX_CHARACTERISTIC;



		err1 = sd_ble_uuid_vs_add(&nus_base_uuid, &p_ble_nus_c->uuid_type);
    //VERIFY_SUCCESS(err_code);
		APP_ERROR_CHECK (err1);
		uart_uuid.type = p_ble_nus_c->uuid_type;
    uart_uuid.uuid = BLE_UUID_NUS_SERVICE;
		
    p_ble_nus_c->conn_handle           = BLE_CONN_HANDLE_INVALID;
    p_ble_nus_c->evt_handler           = p_ble_nus_c_init->evt_handler;
    p_ble_nus_c->handles.nus_rx_handle = BLE_GATT_HANDLE_INVALID;
    p_ble_nus_c->handles.nus_tx_handle = BLE_GATT_HANDLE_INVALID;

    return ble_db_discovery_evt_register(&uart_uuid);
}

the problem here will be in this function in ble_nus_c.c:

void ble_nus_c_on_db_disc_evt(ble_nus_c_t * p_ble_nus_c, ble_db_discovery_evt_t * p_evt)
{
    ble_nus_c_evt_t nus_c_evt;
    memset(&nus_c_evt,0,sizeof(ble_nus_c_evt_t));

    ble_gatt_db_char_t * p_chars = p_evt->params.discovered_db.charateristics;

    // Check if the NUS was discovered.
    if (p_evt->evt_type == BLE_DB_DISCOVERY_COMPLETE &&
        p_evt->params.discovered_db.srv_uuid.uuid == BLE_UUID_NUS_SERVICE &&
        p_evt->params.discovered_db.srv_uuid.type == p_ble_nus_c->uuid_type)
    {

        uint32_t i;

        for (i = 0; i < p_evt->params.discovered_db.char_count; i++)
        {
            switch (p_chars[i].characteristic.uuid.uuid)
            {
							
							case BLE_UUID_NUS_TX_CHARACTERISTIC:
                    nus_c_evt.handles.nus_tx_handle = p_chars[i].characteristic.handle_value;
                    break;

                case BLE_UUID_NUS_RX_CHARACTERISTIC:
                    nus_c_evt.handles.nus_rx_handle = p_chars[i].characteristic.handle_value;
                    nus_c_evt.handles.nus_rx_cccd_handle = p_chars[i].cccd_handle;
                    break;

                default:
                    break;
							
            }
        }
        if (p_ble_nus_c->evt_handler != NULL)
        {
            nus_c_evt.conn_handle = p_evt->conn_handle;
            nus_c_evt.evt_type    = BLE_NUS_C_EVT_DISCOVERY_COMPLETE;
            p_ble_nus_c->evt_handler(p_ble_nus_c, &nus_c_evt);
        }
    }
}

as BLE_UUID_NUS_RX_CHARACTERISTIC = BLE_UUID_NUS_TX_CHARACTERISTIC = 0x5343

which will make an error on ble_nus_c_on_db_disc_evt() function.

Also NRF_SDH_BLE_VS_UUID_COUNT = 3 is well done.

i won't be able to send /receive messsages in this case between the central (nrf51) and the periph (RN4871).

i hope i clarified what i mean!

RE: creating custom service and characteristics with different Base UUID : connecting and discovering

Kenneth — Thu, 27 May 2021 12:39:40 GMT

You will need to add a BASE UUID for each of these. So make sure that NRF_SDH_BLE_VS_UUID_COUNT is set to 3 (or more).

To add a BASE UUID you will need to call sd_ble_uuid_vs_add() for each BASE UUID you want to add, e.g. something like:

sd_ble_uuid_vs_add(base_uuid1, uuid_type1);

Then to add the service or characteristic you use sd_ble_gatts_service_add(), where you refer to the uuid_type you received from sd_ble_uuid_vs_add() above, e.g. something like:

sd_ble_gatts_service_add(BLE_GATTS_SRVC_TYPE_PRIMARY, uuid_type1, service_handle);

Kenneth