Can not get characteristic UUID

[forrestDun]

Hi team,

My 52832 act as central device. It can discover service and characteristic of peripheral. The problem is it can't get the UUID of every characteristic of service from peripheral when I debug with keil. But it is very weird that it can get the other attribute of characteristic, like read or notify, like the first image. I don't know what wrong thing I have did.I hope I can get some direction of checking from you.The peripheral is a heart rate device which I bought from Internet. My program is base on \ble_central\ble_app_hrs_c.

Other information: nRF5_SDK_12.3.0_d7731ad s132_nrf52_3.1.0

#define GW64_BASE_UUID   {{0x55, 0xE4, 0x05, 0xD2, 0xAF, 0x9F, 0xA9, 0x8F, 0xE5, 0x4A, 0x7D, 0xFE, 0x00, 0x00, 0x53, 0x49}} /**< Used vendor specific UUID. */

uint32_t ble_hrs_c_init(ble_hrs_c_t * p_ble_hrs_c, ble_hrs_c_init_t * p_ble_hrs_c_init)
{
    VERIFY_PARAM_NOT_NULL(p_ble_hrs_c);
    VERIFY_PARAM_NOT_NULL(p_ble_hrs_c_init);

ble_uuid_t hrs_uuid;

/*my_debug begin*/
	uint8_t err_code;
	ble_uuid128_t glu_base_uuid = GW64_BASE_UUID;

VERIFY_PARAM_NOT_NULL(p_ble_hrs_c);
VERIFY_PARAM_NOT_NULL(p_ble_hrs_c_init);

err_code = sd_ble_uuid_vs_add(&glu_base_uuid, &hrs_uuid.type);
VERIFY_SUCCESS(err_code);

	hrs_uuid.uuid = 0x5343;
/*my_debug end*/

    p_ble_hrs_c->evt_handler                 = p_ble_hrs_c_init->evt_handler;
    p_ble_hrs_c->conn_handle                 = BLE_CONN_HANDLE_INVALID;
    p_ble_hrs_c->peer_hrs_db.hrm_cccd_handle = BLE_GATT_HANDLE_INVALID;
    p_ble_hrs_c->peer_hrs_db.hrm_handle      = BLE_GATT_HANDLE_INVALID;
	p_ble_hrs_c->peer_hrs_db.noty_cccd_handle = BLE_GATT_HANDLE_INVALID;
	p_ble_hrs_c->peer_hrs_db.noty_handle      = BLE_GATT_HANDLE_INVALID;

return ble_db_discovery_evt_register(&hrs_uuid);
}

(/attachment/012eaafb98ebd7b15eea5e44221e8cdf)

[run_ar]

Not easy to know exactly what you are doing. Did you modify the example in any way? Note that the Heart rate client only discovers uuid's that are registered with the discovery module. Check for ble_db_discovery_evt_register in your code.

[forrestDun]

Hi run_ar, I have update my question, please read it again. Thank you.

[run_ar]

I'm sorry this slipped through the cracks, did you solve it? Since it looks like your peripheral only have vendor specific UUID's it might be better if you use our nus client example. Start by just replacing the nus UUID's and check if you can discover a couple of characteristics, then add the rest. If you need both HR and custom, add the nus client to your project and leave the hrs client as is.

[forrestDun]

Hi run_ar, I have done the experiment as your indication. The result is same with description of my previous question. ble_uuid128_t tx_base_uuid = {{0x18, 0x03, 0xa6, 0x28, 0x5e, 0xd8, 0xec, 0x91, 0x1c, 0x48, 0xA3, 0xac, 0x00, 0x00, 0x53, 0x49}}; err_code = sd_ble_uuid_vs_add(&tx_base_uuid, &ble_uuid.type); VERIFY_SUCCESS(err_code);

ble_uuid.uuid = 0x5343;

[run_ar]

Are you sure you are trying to discover the correct UUIDs? It's possible to use sd_ble_gattc_attr_info_discover to get a BLE_GATTC_EVT_ATTR_INFO_DISC_RSP. Unfortunately this is not part of the discovery module. But that is the function used by nRF connect to discover unknown UUIDs.