11 Replies Latest reply on Mar 7, 2018 7:32 AM by e.pratt_1639216

    Private random resolvable address and bonding between PSoC4 peripheral and a smartphone


      Hello everybody,


      I am trying to implement the following scenario: using a PSoC 4 BLE peripheral I updated the privacy example and I am trying to use it in my project. I start the peripheral using a public address; then I connect with an android smartphone to the device, pair it using a fixed passkey, bond the device and afterwards the phone disconnects. After the disconnecting event, the address of my peripheral becomes private random resolvable which is what I want, it even changes ones at a couple of minutes again if there is no connection or every time a connection/disconnection event arrived. Everything is good, but my problem is the following, after I disconnect with the smartphone from the peripheral and the address become private I am not able to reconnect with my smartphone again. Does anyone know if android itself can resolve an address or if the application should scan every time for a device and try to resolve itself the address? I would like to reconnect to a bonded device without scanning, but I do not know if this is possible.


      If anyone experienced this, a hint is more than welcomed.


      Thank you,



      Update info: The security of my device is set to Mode 1, authenticated pairing with encryption, Strict pairing, Display as IO capability(even if this is not entirely correct, the device has no i/o capabilities but I want to use a fixed passkey for this). I observe that the bonding initiated by the smartphone and the exchange of keys is ok. After disconnect event and the address become private I can scan all devices, find the one I need with the orivate address and can connect to it without any bonding. The problem is now the following: after connection and accessing a service(ex. battery level) I am no longer able to do anything. If I try a read than the pairing winodw will pop up again and no matter what I enter the device disconnects.


      Update info 2:

      Here is a new Update and the project attached. I eliminate all the code except my two state machines that handle this bonding and privacy tasks. Please note in BLEHandler.c that some code is commented since it makes no sense in this test project, especially the fact that remove bonding is done by pressing a button and in the project it is done at reset.


      The battery level as it is in SIG has encryption and authenticated on Read. Therefore indeed that may trigger the pairing window again. I am not an expert in how Android or iOS will treat this but if I remove the encryption an authentication than everything is fine. But I do not want to modify this, and I still want some privacy on other custom characteristics, even if after a bonding only that phone can resolve the address.


      Other Info: with the cypress dongle and cysmart on PC, when reconnect to the private address, it will pop up the pairing but after ok it says paring completed without the entering pin.


      One of my other questions will be: Is there something wrong in how I handle this process in the peripheral? Is there a problem with the application on android and there I should invest some time?


      It would be great if someone can point me in a more correct direction. Thank you!


      Message was edited by: Marian-Emanuel Ionascu