How to recognize unpair android command at firmware BLE_GAP_EVT_DISCONNECTED event

[vannikit]

Hello! 

I use nRF52-DK wuth android device. DK connects to android device and  works with it well. But I want a paired DK make unpaired from android device by performing unpair command, which will be accompanied by pm_peers_delete() functions (or something else) in firmware. For this I am trying to use BLE_GAP_EVT_DISCONNECTED event at firmware. But I can't recognize unpair android event from another android events (like just switch power off). I have not met example with this future implemented. I feel that I am going in wrong way or I should use another events. Would you give me prompt or show code example with true way to implement this future.

[Amanda Hsieh]

Hi, 

 

But I can't recognize unpair android event from another android events (like just switch power off).

 You will get both of the disconnect reasons are the BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION.

The peer manager which handles pairing requests will for security reasons reject new pairing requests from an already bonded peer device. You could add the following event handling to the PM callback if you want to allow repairing:

       case PM_EVT_CONN_SEC_CONFIG_REQ: 
       {
            pm_conn_sec_config_t config = {.allow_repairing = true};
            pm_conn_sec_config_reply(p_evt->conn_handle, &config);
       }

The other alternative is to actually delete the bond from the nRF device. For the SDK examples, you can delete all bonds by pressing board button 2 while resetting the device.

 -Amanda H.

[vannikit]

Thank you for quick answer, Amanda! 

I tried you advise. It works.

But as I understood, I can't  recognize real reason of host device disconnection. It can be switching Bluetooth off or unpair command and nRF device will always obtain  BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION flag in BLE_GAP_EVT_DISCONNECTED event. So should use another events (buttons or another source) to clear pairing from nRF side. Correct?

[Amanda Hsieh]

Hi, 

If you print out the dissconnect.reason in the BLE_GAP_EVT_DISCONNECTED event, you will see that the disconnection code is the same whether the android device is turned off or deletes unpair. Therefore, you should use another way to delete bond info. by pressing board button 2 on DK while resetting the device. You can refer to the Heart Rate Application example for the delete bonds. 

        case BLE_GAP_EVT_DISCONNECTED:
            NRF_LOG_INFO("Disconnected, reason %d.",
                          p_ble_evt->evt.gap_evt.params.disconnected.reason);
            m_conn_handle = BLE_CONN_HANDLE_INVALID;
            break;

-Amanda H

[vannikit]

Amanda Hsieh said:

If you print out the dissconnect.reason in the BLE_GAP_EVT_DISCONNECTED event, you will see that the disconnection code is the same whether the android device is turned off or deletes unpair.

Yes, I agree.

I saw one reason only for several types of events (disconnection or unpairing). So I will use pairing clear by another way.

Thank you,  Amanda.