What is the right procedure to un-bond/unpair nRF52840 from host?

[min-ching]

Hi, 

    I tried to erase the bound and start another pairing procedure without rebooting my device. I was not able to remove the bond correctly. The system hangs when I call pm_peers_delete(). The problem is right after I call this function, a PM_EVT_PEERS_DELETE_SUCCEEDED event is sent to event handler and another advertising is started. Down in ble_advertising_start(), when it calls sd_ble_gap_adv_set_configure(), the function returns NRF_ERROR_INVALID_STATE. What is the right procedure to remove the bond properly? Can I temporary shutdown BLE before erase bond and resume it after removal?

Thank you,

Min-Ching

[haakonsh]

Hey Min-Ching,

You cannot delete a bond while in a BLE connection. You need to disconnect first. 

Cheers,

Håkon.

[min-ching]

Hi Håkon,

    Would you please show me how to do the disconnect properly? 

Thank you,

Min-Ching

[haakonsh]

you need to call sd_ble_gap_disconnect with the connection handle and BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION HCI status code. 

[min-ching]

Hi Haakonsh,

     I tried this API. Right after BLE_GAP_EVT_DISCONNECTED event, a BLE_GAP_EVT_CONNECTED happened immediately. I don't have chance to erase the bonding. How can I prevent that?

Min-Ching

[haakonsh]

I believe that your application has set up it logical state machine to start advertising on a BLE_GAP_EVT_DISCONNECTED event. You need to follow this event throughout your application or search for your "advertising_start" function name. 

It might be in the advertising module, a service, main loop, or some event handler somewhere. 

[min-ching]

Hi Haakonsh:

    I found there is a advertising_start when event "PM_EVT_PEERS_DELETE_SUCCEEDED" is received. I have moved this from the code. I was able to get rid of "immediately reconnect" problem. Now, I was not able to restart another advertising after delete the previous pairing. 

    What I did for delete bond is 1. call sd_ble_gap_disconnect(m_conn_handle, BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION); 2. After disconnect call pm_peers_delete();

    After delete the bond, I manually trigger another advertising and I get error NRF_ERROR_INVALID_STATE when the code execute sd_ble_gap_adv_set_configure(&p_advertising->adv_handle, p_advertising->p_adv_data, &p_advertising->adv_params); in ble_advertising_start().

    I don't have any idea what is wrong here. Any suggestions?

Thank you,

Min-Ching

[haakonsh]

Hey Min-Ching,

From the sd_ble_gap_adv_set_configure SPI reference i found that the error code NRF_ERROR_INVALID_STATE means:

"Invalid state to perform operation.

• It is invalid to provide non-NULL advertising set parameters while advertising.
• It is invalid to provide the same data buffers while advertising. To update advertising data, provide new advertising buffers."

Cheers,

Håkon.

[min-ching]

Hi Håkon,

     I checked all the parameter passed into sd_ble_gap_adv_set_configure. The advertising set parameter is not null. However, the data buffer pointer is the same. I don't understand why this buffer must be different when all your sample code uses BLE_ADVERTISING_DEF(m_advertising) to create a buffer and reused it. Does this mean when I call this API the device is already in advertising mode? Any other thing we can check? Do you have any good example code that I can take a look? 

Thank you,

Min-Ching Ho

[haakonsh]

You should definitely be able to use the same buffer, but it does make sense for the SoftDevice to reject a call to update the advertising parameters of an active advertiser if the parameters are exactly the same. 

It might be that you need to turn off the whitelist after deleting the bonds, you can try a call to 

ble_advertising_restart_without_whitelist. 

[min-ching]

I found I need to call sd_ble_gap_adv_stop either right after bonded or before delete the bond. After I add this in, I no longer see NRF_ERROR_INVALID_STATE problem.

Min-Ching

[haakonsh]

Glad to hear it worked out^^