Win 10 BLE stacks, acting as a central, problems accepting BLE connection parameter changes.

[ianm]

Background: In a previous posting I had asked if anyone knew of BLE connection parameter guidelines for Windows 10. The general response was, yeah ios has BLE connection parameter guidelines, but it doesn't appear that Windows 10 (or Android for that matter) has any such guidelines.

I have a Nordic nRF52 development board we are developing a peripheral BLE application on. When I use a Win 10 laptop (Dell Precision 7520) as a BLE central to the Nordic peripheral, connection is just fine. However, when the peripheral attempts to change the connection parameters >20ms, or change slave latency >1, it usually doesn't 'take'. Meaning not accepted by the central (win 10) BLE stack. I confirm the accept/reject of these via Teledyne'LeCroy Sodera LE sniffer.

Note: when using an Android phone as a BLE central, generally speaking its BLE stack accepts the connection parameters that the win 10 BLE stack rejects.

Question: Does anyone have any insight into win 10 BLE stacks? Are then from Microsoft? specific to device manufacture (in this case Dell), specific to chipset?

note, I have asked similar questions on MSDN forums and I've started working with Dell... though I DO have their most recent Bluetooth driver (for my laptop).

However, of anyone, my guess is that Nordic developers may have the best insight into this.

[ianm]

Hi david,

I have re-done my 'set connection parameters' via the PPCP (Preferred Peripheral Connection Parameter) Characteristics using the same software running on a Nordic nrf52 development board running as a BLE peripheral, but with 2 different BLE centrals, an Android phone, and an Win 10 Dell Laptop.

short answer:

o with the Android phone as a central, no problem setting connection parameter intervals see L2CAP 'Connection Parameter Update Request', and 'Connection Parameter Update Response (accepted)' pair, along with LE LL 'LL_CPNNECTION_UPDATE_IND' o with Win 10 device as central, initial connection is at 20 ms (using range of 7.5 ms to 500 ms), when attempt to set to 20 ms, 640 ms, yes I see the L2CAP pair 'Connection Parameter Update 'Connection Parameter Update Request', and 'Connection Parameter Update Response (accepted)' pair, along with LE LL 'LL_CPNNECTION_UPDATE_IND' and the connection interval stays at 20 ms o with WIn 20 device as central, when I attempt to set connection intervals 40 ms, 40ms, the L2CAP pair 'Connection Parameter Update 'Connection Parameter Update Request', and 'Connection Parameter Update Response (accepted)' pair appears 3 times in my Sodera LE logs, but a LE LL 'LL_CPNNECTION_UPDATE_IND' never follows... and the connection interval stays unchanged at 20 ms. I don't see a way to send any attachments here, I will see if I can do this with a private message.

hi David, following your 'clip' instructions I will attach my Sodera LE files for my android and win 10 experiments.

android experiments: see ConnectionParameters.Android.Exp.doc, and _153851. files win 10 experements: see Connection Parameters.Win10BLe4_2Exp.AfterDellUpdate.doc, and _165038. filesConnectionParameters.Android.Exp.doc(/attachment/10e80f2163ed8c98bf9c2a29fb993f2e)(/attachment/85a3a7bc13049eb50c7925e6be6cd650)(/attachmen/afe27087918e3df3c0b4ab41d8af7198)(/attachment/c288201f7a99e6ac8b23c6defc735da1)ConnectionParameters.Win10Ble4_2.Exp.AfterDellUpdate.doc(/attachment/de738b64ada022afd71e624da0c48bbb)

[David Edwin]

You can attach files to your question or answer. The should be "clip" like icon that can be used to add attachments.

[David Edwin]

I would definitely want to you to take a look at the Desktop 2 code for the connection parameters update.

[ianm]

hi David, I updated my post with attachments.

[David Edwin]

could not get the frontline sodera viewer to view the .scap file, can you provide a .cfa from fromtline or a .pcap saved from wireshark.

[ianm]

hi David, I did download the NRFReadyDescktop2 source code and compared it to ours our code calls Nordic ble_conn_Params_change_conn_parms(), which in turn calls Nordic sd_ble_gap_conn_params_update() the NRFReadyDesckTop2 source code calls Nordic sd_ble_gap_conn_params_update()... so from a code compare point of view, using the same Nordic calls to set connection parameters. this confirms our theory in that the problem is with the BLE stack we have in our Dell laptop. According to dell, the BLE chip is an "Intel WiFi Link 8265 2x2 802.11ac + BT 4.2", with the BLE stack from intel. do have any knowledge of BLE stacks associated with this chipset?