how to discover 16bit uuid?

Question

Hi. i'm using nRF52832, SDK13.0.0.
I'm developing Central, Peripheral both. 
 If peripheral just has 16bit UUID. It doesn't contain base UUID.
Or if i don't know what peripheral's UUID is, how can I discover it? 
 My central source code has to know 128bit UUID as below. 
 {
......
ble_uuid128_t lbs_base_uuid = {??????? --> how can I define????}; 
 VERIFY_PARAM_NOT_NULL(p_ble_lbs_c);
VERIFY_PARAM_NOT_NULL(p_ble_lbs_c_init);
VERIFY_PARAM_NOT_NULL(p_ble_lbs_c_init->evt_handler);

p_ble_lbs_c->peer_lbs_db.button_cccd_handle = BLE_GATT_HANDLE_INVALID;
p_ble_lbs_c->peer_lbs_db.button_handle = BLE_GATT_HANDLE_INVALID;
p_ble_lbs_c->peer_lbs_db.led_handle = BLE_GATT_HANDLE_INVALID;
p_ble_lbs_c->conn_handle = BLE_CONN_HANDLE_INVALID;
p_ble_lbs_c->evt_handler = p_ble_lbs_c_init->evt_handler;

err_code = sd_ble_uuid_vs_add(&lbs_base_uuid, &p_ble_lbs_c->uuid_type);
if (err_code != NRF_SUCCESS)
{
 return err_code;
}
VERIFY_SUCCESS(err_code);
 
 ...... 
 } 
 How can I discover UUID which i don't know or just 16bits? 
 I need your help.

endnode · Accepted Answer

That's incorrect. All UUIDs are in fact 128-bit long and that's why Nordic represents them always as pair of 128-bit base and 16-bit short UUID. In case that GATT Server presents just 16-bit short UUID that just means that 128-bit base is standard BT SIG base UUID as defined in the spec and hardcoded (as the only one base!) in Nordic BLE stack. So whenever you work with "just short 16-bit UUIDs" (aka standardized BT SIG UUIDs) in Nordic SD GATT API you should use BLE_UUID_TYPE_BLE as reference to 128-bit base index in virtual table of UUID bases (which are provisioned in SD). 
 UPDATE #1 (2017-11-17) 
 Why? Because it's in the code! Someone wrote it there. If not you then Nordic. Why? It doesn't matter, it's there! Do you like it? If yes then write your client accordingly! If not then do following little change on GATT Server side (according to code you posted earlier): 
 uint32_t ble_dfu_init(ble_dfu_t * p_dfu)
{
 ble_uuid_t service_uuid;
 uint32_t err_code;

#ifndef NRF51
 if (p_dfu == NULL)
 {
 return NRF_ERROR_NULL;
 }
#endif

 m_conn_handle = BLE_CONN_HANDLE_INVALID;

 const ble_uuid128_t base_uuid128 =
 {
 {
 0x50, 0xEA, 0xDA, 0x30, 0x88, 0x83, 0xB8, 0x9F,
 0x60, 0x4F, 0x15, 0xF3, 0x00, 0x00, 0xC9, 0x8E
 }
 };
 err_code = sd_ble_uuid_vs_add(&base_uuid128, &p_dfu->uuid_type);
 VERIFY_SUCCESS(err_code);

 service_uuid.uuid = BLE_DFU_SERVICE_UUID;
 service_uuid.type = p_dfu->uuid_type;

 err_code = sd_ble_gatts_service_add(BLE_GATTS_SRVC_TYPE_PRIMARY,
 &service_uuid,
 &(p_dfu->service_handle));
 VERIFY_SUCCESS(err_code);

 // ...

how to discover 16bit uuid?

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