BLE bonding/pairing with pc-ble-driver-py

[james s]

Hi,

Does the pc_ble_driver_py contain any API for paring or bonding bluetooth devices? And if so, do you have any examples or documentation which explain how to use them?

I see that the ble_adaptor class has authenticate() and encrypt() functions which I assume are relevant to pairing, but I don't know how to implement them. The included heart rate collector example does not use these functions, and I can't find any documentation which explains them. My problem sounds similar to this issue below, but that is from over 2 years ago. Is there any new information you can give me?
Thanks,

https://devzone.nordicsemi.com/f/nordic-q-a/17497/pc-ble-driver-py-pairing-bonding

James

[Jørgen Holmefjord]

Hi,

You should have a look at the API documentation of the softdevice functions mentioned in the implementation of Authenticate and Encrypt methods, and check how they are used in the SDK examples:

• sd_ble_gap_sec_params_reply
• sd_ble_gap_encrypt

Best regards,
Jørgen

[james s]

Hi Jørgen, thanks for getting back to me.

I've had a look at the documentation you linked to and I'm still having issues with my program. To setup bonding my code is currently: 

self.sec_params = BLEGapSecParams(bond=True,
                                  mitm=False,
                                  lesc=False,
                                  keypress=False,
                                  io_caps=BLEGapIOCaps.none,
                                  oob=False,
                                  min_key_size=7,
                                  max_key_size=16,
                                  kdist_own=self.kdist_own,
                                  kdist_peer=self.kdist_peer)

self.adapter.driver.ble_gap_authenticate(self.conn_handle, self.sec_params)
self.evt_sync.wait(evt="sec_params")
self.adapter.driver.ble_gap_sec_params_reply(self.conn_handle,
                                             BLEGapSecStatus.success,
                                             None)

But this fails with the message "pc_ble_driver_py.exceptions.NordicSemiException: Failed to ble_gap_sec_params_reply. Error code: 8"

I have also tried running:

collector.adapter.authenticate(conn_handle, bond=True)

But this failed with the same error. Is there something I'm missing that's causing this?

Thanks,

James

[Jørgen Holmefjord]

This error code is described in the API documentation:

This function is only used to reply to a BLE_GAP_EVT_SEC_PARAMS_REQUEST, calling it at other times will result in an NRF_ERROR_INVALID_STATE.

Where did you call it from? Are you developing a central or peripheral application using pc-ble-driver-py?

[james s]

I'm calling it from the main function of the program, after a connection has been established. I'm developing a central application using the heart_rate_collector example as a starting point, and I'm trying to extend its functionality to include pairing / bonding.

[james s]

I've solved it now, I needed to delete the bond information from the peripheral device which I was connecting to between tests. This is why it wasn't sending a ble_gap_evt_sec_params_request.

Thanks for your help!