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  • Case ID: 118170
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No disconnect event after bond on Android

Mindaugas

Hello,

To reproduce this problem I use these steps:

  1. Bond to NRF51822 using Android 6.0.1 and latest nRF Connect version;
  2. After successful bond, connect to NRF51822;
  3. Use "DISCONNECT" button in nRF Connect application;

After these steps my application does not get BLE_GAP_EVT_DISCONNECTED event. As a consequence it does not advertise.

I am using custom board with NRF51822, S130 v2.0.1, SDK v12.1.0. My application has a custom profile. Note: problem is also reproducible with ble_app_hrs_freertos example.

Some insights:

  1. If I repeat connect/disconnect action from nRF Connect for few times I eventually get BLE_GAP_EVT_DISCONNECTED with reason BLE_HCI_LOCAL_HOST_TERMINATED_CONNECTION. After that I get disconnect events in application on every disconnect from android.
  2. If I turn off bluetooth on mobile phone or reset NRF51822 after bond, I receive disconnect event later on;
  3. This behaviour does not reproduce with S110 and SDK v10;
  4. This behavior does not reproduce with android version 5.0;
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  • 0

    I also notice the behavior you described. This is an "issue" on the client (Android phone) and not on the server.

    When a BLE peripheral is bonded to an Android phone (from Android 6 an higher ?), the disconnect request is not sent most of the time. If you are connected, as soon as you "forget" the bonded device, you will receive the disconnect event. If you turn the Bluetooth off on your phone, you will also get the disconnect event after the timeout you defined in the connection parameters.

    The Android API has only one method to disconnect. I used an Ellisys sniffer and no disconnect request are sent at all if the device is paired. You can to the test yourself. You can forget the bonded device using the "bonded" tab in nRF Connect for Android.

    This behavior is also quite annoying for me. It appends on Android Nexus phones running Android 6 and 7. You can use any demo application on the server, you will get the same behavior, unfortunately.

    Turning off the Bluetooth on the phone or removing a paired device is not acceptable. As a workaround, you could send the disconnect request from the server (you could write to a characteristic value to the server or another similar mechanism).

    The disconnection in BLE is always a bit tricky. This behavior on Android is not very clear for me. On iOS, the disconnect request has the same behavior with paired devices or not.

    Any Android developer at Nordic could help us with this issue ?

Reply
  • 0

    I also notice the behavior you described. This is an "issue" on the client (Android phone) and not on the server.

    When a BLE peripheral is bonded to an Android phone (from Android 6 an higher ?), the disconnect request is not sent most of the time. If you are connected, as soon as you "forget" the bonded device, you will receive the disconnect event. If you turn the Bluetooth off on your phone, you will also get the disconnect event after the timeout you defined in the connection parameters.

    The Android API has only one method to disconnect. I used an Ellisys sniffer and no disconnect request are sent at all if the device is paired. You can to the test yourself. You can forget the bonded device using the "bonded" tab in nRF Connect for Android.

    This behavior is also quite annoying for me. It appends on Android Nexus phones running Android 6 and 7. You can use any demo application on the server, you will get the same behavior, unfortunately.

    Turning off the Bluetooth on the phone or removing a paired device is not acceptable. As a workaround, you could send the disconnect request from the server (you could write to a characteristic value to the server or another similar mechanism).

    The disconnection in BLE is always a bit tricky. This behavior on Android is not very clear for me. On iOS, the disconnect request has the same behavior with paired devices or not.

    Any Android developer at Nordic could help us with this issue ?

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