S120 adding 2 uuids for 2 peripherals

[sowmya]

Hello, I am working on S120 SD v2.1.0 for central and S110 v8.0 SD for peripheral and SDK9.0 and I am able to configure 1 single uuid on central and connect to multiple peripherals with the same UUID.

But now I am trying to configure different UUID for 2 different peripherals, and on the central side I added the UUID as follows:

	ble_uuid_t uuid;
uuid.type = m_base_uuid_type;
uuid.uuid = BLE_UUID_NUS_SERVICE;

err_code = ble_db_discovery_evt_register(&uuid, db_discovery_evt_handler);
APP_ERROR_CHECK(err_code);

uuid.type = m_base_uuid_type;
uuid.uuid = 0x0002;

err_code = ble_db_discovery_evt_register(&uuid, db_discovery_evt_handler);
APP_ERROR_CHECK(err_code);

i.e., one with NUS service and other with UUID = 0x0002. Now the issue I am facing is, the ID with 0x0002 is not able to connect. When the central connects to the device, I am getting BLE_DB_DISCOVERY_SRV_NOT_FOUND event . Since this is major requirement for my application, can anyone help me in configuring this? I'm I missing anything in configuration?

Regards,
Sowmya

[Anders Strand]

Hey!

Does both the peripherals have the same base uuid? If not, you must add the second base uuid as well with sd_ble_uuid_vs_add (ble_uuid128_t const *p_vs_uuid, uint8_t *p_uuid_type). Store the p_uuid_type, and put this in uuid.type when you call ble_db_discovery_evt_register.

As your code is not, it will use the same base uuid for both services.

Update 1

Since you add two services with ble_db_discovery_evt_register, but with the same callback function, you might be mixing which event comes after which service discovery. The db_discovery module will try to discovery BOTH the services when connection to a new device.

Try adding the second service with a second event handler like this:

err_code = ble_db_discovery_evt_register(&uuid1, db_discovery_evt_handler1);
APP_ERROR_CHECK(err_code);
err_code = ble_db_discovery_evt_register(&uuid2, db_discovery_evt_handler2);
APP_ERROR_CHECK(err_code);

Let us call the NUS service device for device 1. When you connect to it, and do service discovery this should happen:

• db_discovery_evt_handler1 will be called, with the event BLE_DB_DISCOVERY_COMPLETE.
• db_discovery_evt_handler2 will be called, with the event BLEE_DB_DISCOVERY_SRV_NOT_FOUND

Let us call the second device for device 2. When you connect to it, and do service discovery this should happen:

• db_discovery_evt_handler1 will be called, with the event BLEE_DB_DISCOVERY_SRV_NOT_FOUND .
• db_discovery_evt_handler2 will be called, with the event BLE_DB_DISCOVERY_COMPLETE

Can you check the following?

• That your central successfully connects to both devices
• Which results the db_discovery event handlers report for both devices.

[sowmya]

Hi Anders, Yes both peripherals have the same base UUID but different 16-bit service UUID. I am adding UUID in central as follows:

	ble_uuid128_t base_uuid = BLE_UUID_OUR_BASE_UUID;

err_code = sd_ble_uuid_vs_add(&base_uuid, &m_base_uuid_type);
APP_ERROR_CHECK(err_code);

for (i = 0; i < MAX_CLIENTS; i++)
{
	m_client[i].state  = IDLE;
}
m_client_count = 0;
db_discovery_init();

// Register with discovery module for the discovery of the service.
ble_uuid_t uuid;
uuid.type = m_base_uuid_type;
uuid.uuid = BLE_UUID_NUS_SERVICE;

err_code = ble_db_discovery_evt_register(&uuid,
												db_discovery_evt_handler);
APP_ERROR_CHECK(err_code);

    err_code = sd_ble_uuid_vs_add(&base_uuid, &m_base_uuid_type);
APP_ERROR_CHECK(err_code);

uuid.type = m_base_uuid_type;
uuid.uuid = 0x0002;

err_code = ble_db_discovery_evt_register(&uuid,
												db_discovery_evt_handler);
APP_ERROR_CHECK(err_code);

This is the code snippet in,peripheral:

    ble_uuid_t        service_uuid;
    ble_uuid128_t     base_uuid = BLE_UUID_OUR_BASE_UUID;
    service_uuid.uuid = BLE_UUID_NUS_SERVICE;

    // Initialize the service structure.
    p_sos->conn_handle             = BLE_CONN_HANDLE_INVALID;
    p_sos->data_handler            = p_sos_init->evt_handler;
    p_sos->is_notification_enabled = false;

    // add custom base UUID
    err_code = sd_ble_uuid_vs_add(&base_uuid, &p_sos->uuid_type);
    if(err_code != NRF_SUCCESS)
 {
 	return err_code;
 }
     
     service_uuid.type = p_sos->uuid_type;
     
     // Add the service
    err_code = sd_ble_gatts_service_add(BLE_GATTS_SRVC_TYPE_PRIMARY,
                                    &service_uuid,
                                    &p_sos->service_handle);

And the other peripheral configuration is same but the service UUID is set to 0x0002.

I think this is proper, correct?

Regards,
Sowmya

[Anders Strand]

You say "Now the issue I am facing is, the ID with 0x0002 is not able to connect. When the central connects to the device, I am getting BLE_DB_DISCOVERY_SRV_NOT_FOUND event ."

This is confusing. First you say that you cannot connect, and then you say that you connect successfully but are unable to discover services?

Since you look for both services on both devices, you should receive the BLE_DB_DISCOVERY_SRV_NOT_FOUND event on both devices (because they only have one each).

I think you should make two db_discovery handlers, so that you more easily can know which service you are not finding.

Given that you are connecting to both, you should get one BLE_DB_DISCOVERY_SRV_NOT_FOUND and one BLE_DB_DISCOVERY_COMPLETE per peripheral.

[sowmya]

I tested by adding a single service at a time, and it is able to discover and connect. Next, I need the central to connect to 2 different peripherals with different service. I am not getting to know how to add 2 services on the central? The service is not discovering only if I two services in the central. But each peripheral have unique services.

[Anders Strand]

See my updated answer