Get connected device name in Generic Access Service from ble central

Question

Hi all, 
 I would like to get the complete name from the connected peripheral by reading the device name characteristic (0x2A00) in the Generic Access Service (0x1800). I am using SDK 15.2.0 with soft device s132 v6.1.1. 
 I have tried to call sd_ble_gattc_char_value_by_uuid_read in BLE_GAP_EVT_CONNECTED event, and then get the device name through p_ble_evt->evt.gattc_evt.params.char_val_by_uuid_read_rsp.handle_value in BLE_GATTC_EVT_CHAR_VAL_BY_UUID_READ_RSP event. But it never runs inside the event BLE_GATTC_EVT_CHAR_VAL_BY_UUID_READ_RSP. I have tested another way by using p_ble_evt->evt.gatts_evt.params.write.data but it didn't get the device name. 
 So I would like to know how I can do that. 
 Many thanks in advance.

Andy · Answer

I did this once by discovering the characteristic using the discovery module, storing the value handle and then calling sd_ble_gattc_read() using that value handle. It worked like a charm.

Andy · Answer

On your discovery event handler you do this: if ((p_evt->evt_type == BLE_DB_DISCOVERY_COMPLETE) && (p_evt->params.discovered_db.srv_uuid.uuid == gap_profile_s_uuid.uuid) && (p_evt->params.discovered_db.srv_uuid.type == gap_profile_s_uuid.type)) { NRF_LOG_INFO("Found GAP profile service"); // Find the CCCD Handles of the device name characteristic for (uint8_t i = 0; i < p_evt->params.discovered_db.char_count; i++) { if ((p_evt->params.discovered_db.charateristics[i].characteristic.uuid.uuid == device_name_c_uuid.uuid) && (p_evt->params.discovered_db.charateristics[i].characteristic.uuid.type == device_name_c_uuid.type)) { NRF_LOG_INFO("Found device name characteristic"); device_name_handle = p_evt->params.discovered_db.charateristics[i].characteristic.handle_value; // Break out of for loop break; } } } Then you can use the device_name_handle in sd_ble_gattc_read(). In the offset just write 0. Where you call sd_ble_gattc_read() is up to you, and it doesn't really matter. To get the device name data, you need to do this in you BLE event handler: case BLE_GATTC_EVT_READ_RSP:; ble_gattc_evt_read_rsp_t const * p_read_rsp = &p_ble_evt->evt.gattc_evt.params.read_rsp; NRF_LOG_INFO("Read length: %d, Read offset: %d", p_read_rsp->len, p_read_rsp->offset); // We are reading the device name if (p_read_rsp->handle == device_name_handle) { for (uint8_t i = 0; i < p_read_rsp->len; i++) { device_name[i + p_read_rsp->offset] = p_read_rsp->data[i]; } device_name_length = p_read_rsp->len + p_read_rsp->offset; } break;