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,

Please try to capture a sniffer trace . It's easier to understand what happened over the air by looking at the sniffer trace. My suspicion is that the connection has never been made. You receive the CONNECTED event on the phone simply because the phone sent the connect request and this doesn't mean the peripheral received the request. Then you will have what showed in the log. However this doesn't explain why it worked with nRFUART but not MCP with autoconnect or nRFToolbox. Could you try to test on other phone ? Also try to turn off and on bluetooth and/or restart the phone.