Nordic_UART auto-disconnection issue on Android L

[Alex Zhang]

Hi Nordic Expert,

I am Alex and have been developing with NRF51822 for a long time. Thanks for your quick help before. Now our product bases on S110-7.1.0 and SDK-6.1.0, and we reuse the demo Noridc UART profile inside our first BLE product. In other side, we also use many tools from you to do testing and verifying, such as MCP, NRF toolbox and NRF UART.

Now I met a very srange issue about that UART profile. Before this, the UART profile worked fine on Andrioid 4.4 (KitKat) platform. But recently we move to use Android 5.0 (L), we found an issue that once we do a connection with that profile, in a very short time it seems our BLE device is auto disconnected, and then this procedure repeats again and again when using NRF toolbox UART(ver 1.16.1). See attached figures.

Later I tried with NRF UART (V2.0) and surprised that this tool can build very stable connection with my device. And then I try MCP tool. Yip, it also can find the device, if I directly click 'connect' button, all is the same as NRF UART. But if I choose to click 'connect with autoConnect', the same issue is duplicated as NRF toolbox. I am so confused with this phenomenon. Any tips? I attached some screenshots for your reference.

Look forward to seeing your answer and help. Thanks a lot.

Alex

[Hung Bui]

Hi Alex,

I tested here with what you recommended and a Galaxy S6 (Android 5.1.1). But couldn't reproduce the issue. Connection kept. My suggestion is to try on another central device (another phone). Also please send us a sniffer trace if possible (the PCA10001 can be used as the sniffer)

[Alex Zhang]

Hi Hung and Alexsander, Sorry for not following up with you as on business these days. I set up sniffer and capture some logs for your further reference. I found it seems the unexpected disconnection issue appears only on Xiaomi Note 2 device since I tried again with Huawei Phone device (Android 5.0.2) but no this issue. Please help to analyze the trace. Look forward to your replay. Thanks a lot.

P.S. issue_auto_disconnect.pcap