Service changed leading to disconnection

RE: Service changed leading to disconnection

Vidar Berg — Mon, 15 Jul 2024 11:09:16 GMT

Correct. iOS will then repeat the service discovery on every connection.

RE: Service changed leading to disconnection

nrbrook — Mon, 15 Jul 2024 11:07:17 GMT

Ok so have the service changed characteristic present, but don’t send an indication, and iOS will not cache when unbonded?

RE: Service changed leading to disconnection

Vidar Berg — Mon, 15 Jul 2024 10:54:33 GMT

It does. So, I'm afraid your only option is to manually clear the cache after changing the firmware in order to allow the iPhone to discover that the service changed characteristic has been added.

RE: Service changed leading to disconnection

nrbrook — Mon, 15 Jul 2024 10:41:42 GMT

We didn’t have service changed before. Does that mean that iOS can cache it? Yes we have seen it with multiple phones.

RE: Service changed leading to disconnection

Vidar Berg — Mon, 15 Jul 2024 10:35:21 GMT

Strange. I have not experienced this myself, nor do I recall seeing any reports about it. The specification is quite clear on this too (the nRF5 SDK does not support the mentioned 'Hash Database' characteristic):

The only case I can think of where this would be expected is if the device was programmed initially with an application that did not include the Service changed characteristic.

Have you seen this with multiple iphones?

RE: Service changed leading to disconnection

nrbrook — Mon, 15 Jul 2024 10:12:53 GMT

Ok it sounds like an iOS bug then. It does seem to cache attributes without bonding, we have to toggle bluetooth off and on to get it to refresh, which is why I was trying to get service changed working.

RE: Service changed leading to disconnection

Vidar Berg — Mon, 15 Jul 2024 09:41:48 GMT

Hello,

The log indicates that the connection was terminated by the iPhone. I'm not sure exactly why it does this. But as you may know, there is no attribute caching when the Service Changed characteristic is present and there is no trusted relationship between the devices (i.e., no bond), so it should be redundant to send a Service Changed notification on connection as the phone will have just performed the service discovery anyway. Is the attribute table being updated during connections in your case?

Best regards,

Vidar