Android Connection drop after few seconds only with Softdevice 6.1.0

[Nikolay]

Hello, 

I am observing problems with Softdevice 6.1.0 and Android. After successful connection and service discovery I never receive a BLE_GAP_EVT_DATA_LENGTH_UPDATE which causes the connection to drop in a few seconds with:

<info> MAIN: Connection 0x0 has been disconnected. Reason: 0x22

The problem is not observed on iOS.

I have tested using the HRS example (as comes from the SDK) and the nRF Toolbox using 3 different versions:

sdk 14.2-2.0_17b948a / softdevice s140_nrf52840_5.0.0-2.alpha_softdevice.hex - No connection drop

sdk nRF5_SDK_15.0-2.0_a53641a / softdevice s140_nrf52_6.0.0_softdevice.hex - no connection drop

sdk nRF5_SDK_15.2.0_9412b96 / soft device s140_nrf52_6.1.0_softdevice.hex - connection drops no matter of what firmware is uploaded

sdk nRF5_SDK_15.2.0_9412b96 / soft device s140_nrf52_6.0.0_softdevice.hex - no connection drop

Device : Samsung S7 with Android 8.0.0

As far as I know in the past releases there was a compatibility mode for overlapping LL procedures, but should I change something to bring it back in the latest Softdevice?

Have you observed such issues? I have lost a day of debugging what is wrong with my firmware until I have discovered this.

Thanks!

[Sigurd]

Hi,

I believe this is caused by an interoperability issue present in S140 v6.1.0, it is fixed in S140 v.6.1.1. In the release notes it's described as "Improved interoperability for the data length update procedure". You can download the new S140 version from this link.

[Nikolay]

Hi Sigurd,

Thank you for the quick update! Unfortunately the link you provided doesn't work. I receive a timeout exception stack trace on the page.

[Sigurd]

There seems to be some issues with the website. I have attached the S140 v.6.1.1 in this post.

Attachment: S140v6_1_1.zip