New association request on second Central connection

[Armando]

Hi,

I'm encountering a strange problem with the nRF52832 when it works as Central with two bonded Peripherals connection.

In particular I'm able to secure the connection with the first Peripherals by calling the pm_handler_secure_on_connection() function as soon as the BLE_GAP_EVT_CONNECTED event is sent by the softdevice.

When I establish the connection with the second one Peripheral (a smartphone) I receive a new association request on the smartphone display, please consider that the device was previously bonded.

If I accept the new pairing with the device (by pressing “OK” on the smartphone display, I use the Just Works method) a new bonding occurs and the connection is secured, after a disconnection I have to pair again.

I use the scan with policy WHITELIST and I call the  sd_ble_gap_connect() function when the NRF_BLE_SCAN_EVT_WHITELIST_ADV_REPORT occurs.

Any idea about the problem?

[Armando]

Hi Edvin,

I perform the following steps during my tests:

1) turn-on my board (with nRF52832 - Central)

2) clear the bonding information (by calling the pm_peers_delete() function)

3) perform a scan with filter policy BLE_GAP_SCAN_FP_ACCEPT_ALL

4) connect and pair with bonding the two devices (not already bonded with my board) that contains particular UUID into the advertising packet. The first one device is a smartphone and the second one is a PCA10040 board with the ble_app_hrs example of the SDK 16.0. 

5) disconnect the devices after bonding

6) start a new scan with filter policy  BLE_GAP_SCAN_FP_WHITELIST

The first connection with the PCA10040 board is established without new association but the second one, with the Android smartphone, requires a new association.

Thank you for your attention.

[Edvin]

Armando said:

5) disconnect the devices after bonding

 How do you do this? Button press? Disconnect from phone? nRF52 reset? What does the log say?

The first pairing doesn't require you to click "pair" or enter a passkey, but not the second one, is that what you mean by "association"?

Did you try to sniff the connection?

Does this happen on more phones? Have you tried other Android phones? iPhones?