Multiple data on single characterstics data write (notify) from peripheral using ble_app_uart Appication

[Brajesh]

Hi All,

I'm using ble_app_uart Application to send some notifications from Peripheral to central device. I'm using API ble_send_string() to send notifications to other Mobile APP. When i test this setup on nRF UART App, it works fine, nRF App shows single data transfer for single button press on ble device. But on our custom App, we get sometimes single data and sometimes multiple character data change notifications for single button press (ble_send_string() API called only once).

Although i am sure i'm not calling that (ble_send_string)API multiple times for single button press, My doubt is that is there some sort of implementation inside nRF App which rejects multiple data write within a narrow time window or something like that ? Or Out Custom App is doing something wrong ?

Suggestions needed, please reply.

[Aleksander Nowakowski]

Hi, no, we do not filter anything. It must be something in your Android application. It looks like you may have multiple listeners attached or some race conditions. Please check if you get the onCharacteristicChanged ones or multiple times. If multiple, check if the BluetoothGatt object is the same. Maybe you are connected multiple times to a single device.

The source code of nRF UART v2 is available on our website. I think you need to log in there. You may also check the UART profile in nRF Toolbox app: play.google.com/.../details The source code for this app is available on GitHub: github.com/.../Android-nRF-Toolbox (DFU Libary project is also required if you want to compile it on your own).

[Brajesh]

Thank you so much Aleksander. It was really helpful to have this info to clear doubt, looks like we might have to look into the source code if nRF UART App and will have to fix our android app for the same.