Android disconnect issues

[KV]

I am using HRM demo application on nRF52840 DK with Samsung Tab-A. The nRF Connect App is running on the tablet. We are seeing that the dev kit gets disconnected soon after a connection is established. The error code on peripheral side is 0x2A.

Android version is 7.0 Device model number SM-T580 Bluetooth version 4.2

This does not happen on iPhone 7 with the nRFConnect app.

Also, this does not happen on LG Nexus 5 smartphone running Bluetooth version 4.0.

[endnode]

If you have problem with some buggy blackbox (here made by Samsung) failing in BLE connection then you will need Network analyzer/BLE sniffer to understand what happens there.

[Hung Bui]

@KV: Please provide a sniffer trace.

Please state which SDK and which Softdevice you used. Also please confirm you have disconnected reason = 0x2A = BLE_HCI_DIFFERENT_TRANSACTION_COLLISION, this disconnect reason usually happens when the peer (the phone) violate the spec and send 2 LL link layer request without waiting for response. In S132 we allowed the behaviour. From release note:

The SoftDevice slave role now accepts overlapping peer-initiated Link Layer control procedures (DRGN-8623). The following LL control procedures can be executed in parallel with any other control procedure, except for themselves: LEPing, Feature Exchange, Data Length Update, and Version Exchange. This is done for compatibility reasons.

[KV]

SDK 14.2.0 and Soft device S140 version 5.0.0.-2_alpha. The soft device v6 is not compatible with the latest SDK.

The disconnected reason is BLE_HCI_DIFFERENT_TRANSACTION_COLLISION.

I am trying to set up the latest sniffer (beta release v2.0) with Wireshark and it is functioning intermittently. Sometimes the COM port does not get detected.

[Hung Bui]

Hi KV, On S140 v5.0, the feature is not enabled by default. You can try enable compatibility mode 2 BLE_GAP_OPT_COMPAT_MODE_2 using the sd_ble_opt_set() function. Your case may be similar to this case.

[Madhu]

@Hung Bui Please find the attached sniffer trace from Android device Samsung Tab A SM-T580 with Bluetooth version 4.2. btsnoop_hci.log