nRF Connect fails when using many characteristics

RE: nRF Connect fails when using many characteristics

Aleksander Nowakowski — Thu, 08 Sep 2016 07:57:26 GMT

Thanks for the report. I will check why the nRF Connect hangs after I'm back from vacations. You should be able to group them in more services, let's say 3 services 20 char each.

RE: nRF Connect fails when using many characteristics

bjorn-spockeli — Wed, 07 Sep 2016 13:01:13 GMT

Yes, as far as I know this is only an Android issue, i.e. you should be able to discover all the characteristics as a central on a nRF5x chip. I will report this to the Mobile apps group.

RE: nRF Connect fails when using many characteristics

puz_md — Wed, 07 Sep 2016 12:47:30 GMT

Hi Bjørn, thanks for the reply.

Can you confirm that all characteristics can be read and written reliably when not using Discovery? (e.g. when I implement a Central o nRF5x, I can read by UUID and get the handle in return, which I can use for other function calls.)

Pleas notice that the nRF Connect app also hangs if there are too many characteristics (50+). This is not the case with 'SmartDiscover' or 'BLE Scanner' and I expect this to be a bug in nRF Connect. Would be nice if you could fix that so that I can at least work with the correctly shown characteristics (and go back to scanning).

Our customer decided that we want to have so many characteristics. We provide realtime data from several sensors and communication partners gathered by our module. As long as reading separate values by UUID works, there should not be any problem on our side. It's just a litte inconvenient that we cannot use nRC Connect for testing.

As far as I understand, it should be possible to split the characteristics into different services. We imlpemented something similiar before, but for the current design, out customer decided to put everything into the same service.

Kind regards, Michael

RE: nRF Connect fails when using many characteristics

bjorn-spockeli — Wed, 07 Sep 2016 11:52:29 GMT

Yes, this is a known issue with Android.

http://stackoverflow.com/questions/24531334/is-there-any-limit-on-characteristics-uuid-in-android-ble

https://code.google.com/p/android/issues/detail?id=76639

Apparently, if there are too many characteristics, service discovery will not be performed correctly.

That said, are you sure that you need 48 characteristics in a service? Could you explain your use case?

Best regards

Bjørn