Steps to connect LE device using hcitool only - bluetooth

Question

I am confusing in hcitool because "lescan" is working fine but "lecc" is giving me "time out".
Please help me if any one have proper steps for "How to connect device using hcitool".
I don't want to use gatttool or bluetoothctl tool.
My aim is to connect to take reference of hcitool code and write my own code to connect with ble sensor.
If any one have working peace of the code which is connecting to ble device using "hci_le_create_conn". please explain me here.
Is there any authentication needed? If yes please give me hci related api.
LOG:
command :
hcitool lecc --random 52:B8:47:55:C5:9A
output:
Could not create connection: Connection timed out
sudo btmon output :
# RAW Open: hcitool (privileged) version 2.22 {0x0003} [hci0] 183.156045
< HCI Command: LE Create Connection (0x08|0x000d) plen 25 #202 [hci0] 183.156918
Scan interval: 2.500 msec (0x0004)
Scan window: 2.500 msec (0x0004)
Filter policy: White list is not used (0x00)
Peer address type: Random (0x01)
Peer address: 52:B8:47:55:C5:9A (Resolvable)
Own address type: Public (0x00)
Min connection interval: 18.75 msec (0x000f)
Max connection interval: 18.75 msec (0x000f)
Connection latency: 0 (0x0000)
Supervision timeout: 32000 msec (0x0c80)
Min connection length: 0.625 msec (0x0001)
Max connection length: 0.625 msec (0x0001)
> HCI Event: Command Status (0x0f) plen 4 #203 [hci0] 183.158026
LE Create Connection (0x08|0x000d) ncmd 1
Status: Success (0x00)
# RAW Open: hciconfig (privileged) version 2.22

Answer 1

hcitool is one of the eight tools that have been marked as deprecated by the BlueZ maintainers. The closest replacement would probably be btmgmt
The general guidance is that there are better API's to use to interact with BlueZ as HCI bypasses the Bluetooth daemon running on the system.
As you are looking at coding this, then the recommended API's are either Management Interface:
https://git.kernel.org/pub/scm/bluetooth/bluez.git/tree/doc/mgmt-api.txt
Or the D-Bus API:
https://git.kernel.org/pub/scm/bluetooth/bluez.git/tree/doc/adapter-api.txt
https://git.kernel.org/pub/scm/bluetooth/bluez.git/tree/doc/device-api.txt
You don't say which language you want to code this in, but most languages have DBus libraries that would help. Here is an example doing it with Python:
import pydbus
# Setup of device specific values
dev_id = 'DE:82:35:E7:CE:BE'
# DBus object paths
bluez_service = 'org.bluez'
adapter_path = '/org/bluez/hci0'
device_path = f"{adapter_path}/dev_{dev_id.replace(':', '_')}"
bus = pydbus.SystemBus()
adapter = bus.get(bluez_service, adapter_path)
device = bus.get(bluez_service, device_path)
# Assume device has been paired already so can use connect
device.Connect()