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

[Alex Zhang]

Hi Alexsander, thanks for your comments. Actually we tried this on many devices, e.g. Sumsung Galaxy S5, Xiaomi and Huawei android phones. UART service can work fine on Anrdoid 4.4 device in spite of MCP, NRF UART or Toolbox. I feel confused that why NRF UART v2.0 can make a very stable connection with my device via UART service on Android 5.0. The issue only truns up for Toolbox and MCP with autoConnect. I also read the source code of NRF UART and Toolbox, seeming there does be some differences. As you said, there's one flag set to true. Would you show me in detail?