NRF SD MTU Data Overflow Handling

[Ankit Bhatnagar]

Hi,

I have a working system based on NRF52832, SD132 and SDK 15.0. I am working with with the default MTU as my data requirement is low and everything is working great.

I recently noticed that if however I send data of size more than 20 bytes from the nrf connect app, my application on nrf52 becomes unresponsive (the control does not land in the GATT write cb function) and on the nrfconnect side, I can see the spinner moving for some time and then it eventually drops the ble connection. If I then reconnect, I am able to and work just like before. However sometimes doing this completly crashes my user application on nrf52.

Is there a provision in softdevice for notifying the user application about such MTU overflow situations so that they can be gracefully handled ?

Thanks !

[Ankit Bhatnagar]

Hi,

I am using the android phone app. The version is 4.22.3.

Where do you see this mentioned error ? In the logs?

So assuming I see this error in the logs, am I correct in assuming that in such situations the initiator (android system here) itself will throw an error and that on the device side there will be no activity whatsoever. In other words, I don't need to worry about any such situation arising as the os itself (android / iphone etc) will do the needful ?

Thanks !

[Sigurd]

Ankit Bhatnagar said:

Where do you see this mentioned error ? In the logs?

Yes. In nRF Connect mobile app, you can slide from left to right to view the log.

I'm also getting the error "GATT INVALID ATTR LEN" on the phone when I try to write e.g. 5 bytes to a 4 bytes characteristic.

Ankit Bhatnagar said:

So assuming I see this error in the logs, am I correct in assuming that in such situations the initiator (android system here) itself will throw an error and that on the device side there will be no activity whatsoever. In other words, I don't need to worry about any such situation arising as the os itself (android / iphone etc) will do the needful ?

Correct.