how to disconnect BLE from the nrf5340 device?

Hello,

Yes it is possible to switch between connectable and non connectable mode in an Application. For that take a look into Generic Access profile section of the Bluetooth. GAP---> BT_LE_ADV_CONN and BT_LE_ADV_NCONN. For a reference take a look into this sample from nRF connect SDK 

I need to know how to disconnect from the device side?

For this you can make use of the function bt_conn_disconnect(). This works from the either side (central/peripheral).

Kind Regards,

Abhijith  

Hi Abhijith,

Thank you so much for your response.

Regards,

Navin