Implement the discovery_completed_cb() method to discover all the peripheral services and initialize them to be able to use their writing, reading, notification, and initialization methods in the application (main)

[Higo]

Hello everyone, I'm trying to create a sample code for a central unit on the NRF52840 to work with two services simultaneously, from a single connection with the peripheral.

My tests manage to connect between the central and peripheral devices, but I can't discover all the services on the central unit side and be able to use all the services provided by the peripheral server.

I'll describe my code here, I hope you can help me, thank you in advance.

# On the Peripheral side

I start the BAS, HTS and LBS services.

# On the Central side

In the discovery part, I implement the callbacks, discovery_completed_cb(), discovery_service_not_found_cb((), void discovery_error_found_cb(), and gatt_discover() to use in application,

and call the method bt_gatt_dm_start(conn, NULL, &discovery_cb, NULL); with NULL in the second field to discover all the services.

in the discovery_completed_cb() callback, I don't know how I should manipulate the attributes, see the attributes of the three services (BAS, HTS and LBS) and make their service methods available in the application.

static void discovery_completed_cb(struct bt_gatt_dm *dm, void *context)
{

const struct bt_gatt_dm_attr *attr = bt_gatt_dm_service_get(dm); // Obtém o primeiro atributo de serviço
const struct bt_gatt_service_val *service_val;
//const struct bt_gatt_dm_attr *desc;
//char uuid_str[BT_UUID_STR_LEN];

printf("Descoberta de serviços, características e descritores concluída:\n");

// Itera sobre os serviços e características usando bt_gatt_dm_attr_next
while (attr) {

printk("Handle: %d\n",attr->handle);
//printk("Permi: %d\n",attr->perm);

// Buffer para converter o UUID para string
char uuid_str[BT_UUID_STR_LEN];
bt_uuid_to_str(attr->uuid, uuid_str, sizeof(uuid_str));
printk("UUID: %s\n\n",uuid_str);

if (attr->uuid == 2800){
service_val = bt_gatt_dm_attr_service_val(attr);
}

attr = bt_gatt_dm_attr_next(dm, attr);
}

bt_gatt_dm_data_release(dm);

}

static void discovery_service_not_found_cb(struct bt_conn *conn, void *context)
{
printk("The service could not be found during the discovery\n");
}

static void discovery_error_found_cb(struct bt_conn *conn, int err, void *context)
{
printk("The discovery procedure failed with %d\n", err);
}

static struct bt_gatt_dm_cb discovery_cb = {
.completed = discovery_completed_cb,
.service_not_found = discovery_service_not_found_cb,
.error_found = discovery_error_found_cb,
};

static void gatt_discover(struct bt_conn *conn)
{
int err;

if (conn != default_conn) {
return;
}

err = bt_gatt_dm_start(conn, NULL, &discovery_cb, NULL);
if (err) {
printk("Could not start the discovery procedure, error code: %d\n", err);
}

}

[Kenneth]

Hello,

I think the best way for forward here is to look at some of the examples that have a gatt client, typically the central examples.

For instance \nrf\samples\bluetooth\central_uart\src\main.c

static void discovery_complete(struct bt_gatt_dm *dm,
			       void *context)
{
	struct bt_nus_client *nus = context;
	LOG_INF("Service discovery completed");

	bt_gatt_dm_data_print(dm);

	bt_nus_handles_assign(dm, nus);
	bt_nus_subscribe_receive(nus);

	bt_gatt_dm_data_release(dm);
}

Best regards,
Kenneth