Central device disconnects BLE connection after 30 seconds

RE: Central device disconnects BLE connection after 30 seconds

grzegorz — Thu, 25 Apr 2019 22:33:11 GMT

It would be great if you could report it internally.

RE: Central device disconnects BLE connection after 30 seconds

Kenneth — Thu, 25 Apr 2019 15:56:42 GMT

Good point, seems someone introduced the issue in SDK15.1, since the same line of code does not exist in SDKv15.0. I slightly like the implementation in SDKv15.0 also, since it actually start a timer that will secure the link after a configurable timeout, should not be needed though, but as kind of a "failsafe" it may also work if you require an encrypted link.

In any case, I can report it internally.

RE: Central device disconnects BLE connection after 30 seconds

grzegorz — Wed, 24 Apr 2019 20:10:44 GMT

Thanks Kenneth. I was using pm_handler_secure_on_connection() in ble_evt_handler(). I've switched to pm_handler_secure_on_error() and it works now.

But calling pm_handler_secure_on_connection() wasn't my random choice. It's how it looks like in SDK ANCS example. Why Nordic calls this function in their official example instead of pm_handler_secure_on_error()?

RE: Central device disconnects BLE connection after 30 seconds

Kenneth — Wed, 24 Apr 2019 14:34:45 GMT

I suggest to compare with one of the working SDK examples, though you may want to check out:
https://developer.apple.com/accessories/Accessory-Design-Guidelines.pdf

For instance it says in 23.10 Pairing: "The accessory should not request pairing until an ATT request is rejected using the Insufficient Authentication error code." I can see from the sniffer log you are sending it almost immediately after connection, that won't work.

RE: Central device disconnects BLE connection after 30 seconds

grzegorz — Tue, 23 Apr 2019 19:19:09 GMT

Hi,

I use custom apps on Windows and iOS, but they don't make the disconnection. On Android there is just nRF Connect used for tests. So I think this must be something about BLE stack or BLE standard.

I use SDK 15.3 and SoftDevice 6.1.1.

RE: Central device disconnects BLE connection after 30 seconds

Einar Thorsrud — Tue, 23 Apr 2019 14:31:07 GMT

Hi,

The disconnect reason is what is shown as "Error Code" in the sniffer trace - remote user terminated connection (0x13). This does not indicate an error in itself, it just states that the central side decided to disconnect (for some reason). A 30 seconds match for instance a GATT timeout, but I do not see anything in the sniffer trace that it should be the problem. In that case you should get disconnect reason 0x08 (timeout). Could it be that the software running on the central devices decide to disconnect for some reason? Do you use custom apps?

Which SDK and SoftDevice version do you use?