Notification on wrong UUID characteristic

[Ivan Jug]

I have a service with 2 characteristics, TX and RX. 
On TX the notify is enabled, because TX should send a notification when something changes. I manage to change what is needed but in my Android APP the characteristic which has notification descriptor seems to be RX. Is the notification actually sent through RX characteristic or am I doing something wrong?

But even with descriptor existing and notification being enabled I still don't get the notification.

For now I am simply trying to send TEST to the nRF and this increases counter and I would like to return that value of counter as notification. Which example should I check about that?

I was trying through nRF connect but when notification is enabled it gets flooded and the nRF program crashes. It is probably stuck in loop of confirmation, there is confirmation for notification? 

[Karl Ylvisaker]

Hello,

On TX the notify is enabled, because TX should send a notification when something changes. I manage to change what is needed but in my Android APP the characteristic which has notification descriptor seems to be RX. Is the notification actually sent through RX characteristic or am I doing something wrong?

You will need the central to enable the TX's notification CCCD, for the device to transmit using the TX characteristic.
The RX and TX terms should be used from the perspective of the device that implements them. It is a common mistake to mix up which direction the TX or RX is intended for, it happens all the time.

For now I am simply trying to send TEST to the nRF and this increases counter and I would like to return that value of counter as notification. Which example should I check about that?

The characteristic descriptions and usage sounds very similar to the ble_app_uart examples from the SDK.
The example demonstrates how to set up a 'emulated UART over BLE' connection to another device, which transmits and receives data to/from another device using an RX and TX characteristic with notifications.
I highly recommend that you take a look through that example, to see how this can be implemented. 

I was trying through nRF connect but when notification is enabled it gets flooded and the nRF program crashes. It is probably stuck in loop of confirmation, there is confirmation for notification? 

Are you here talking about nRF Connect for Desktop application, or nRF Connect for smartphone application?
Could you elaborate what you mean when you say that it is flooded, and the program crashes?
What connection interval are you using for your connection?

Notifications require only Link Layer acknowledgement, while Indications require application layer acknowledgement.
Please see this reply by my colleague, for a more detailed description of the differences between notifications and indications.

Looking forward to resolving this issue together!

Best regards,
Karl

[Ivan Jug]

Thank you, I will check what you provided in details. I was using nRF connect for Android. Not sure what it was before but now notifications seem to be working correctly. I guess that data that I tried with was the problem. 

Now my problem is in my own Android app, but by confirming that everything works correctly with nRF app I guess I have to check a bit more about ble on android.

[Karl Ylvisaker]

Ivan Jug said:

Thank you

No problem at all, I am happy to help! :) 

Ivan Jug said:

I was using nRF connect for Android. Not sure what it was before but now notifications seem to be working correctly. I guess that data that I tried with was the problem. 

Aha, I am glad to hear that you think you've located the root of the issue, and that the notifications now seem to be working correctly.

Ivan Jug said:

Now my problem is in my own Android app, but by confirming that everything works correctly with nRF app I guess I have to check a bit more about ble on android.

Alright - please do not hesitate to open a new ticket if you should encounter any issues or questions in the future.

Good luck with your development!

Best regards,
Karl