About disconnection issue on IOS

[muralikrishnan]

Hai,

we are using nRF52832  and Nordic connect for our development and testing work

we are facing disconnection issue on android after ~3min so we changed the CONNECTION_MIN_INTERVAL=8 to 15ms,CONNECTION_MAX_INTERVAL=10 to 20ms

now andriod disconnection issue solved but IOS disconnection issue was not yet solved using Nordic connect ,

Test case

we changed the interval of min and max interval =(30 to 50) (not working)

we changed the interval of min and max interval =(20 to 100) (not working)

so kindly proved some solution for this 

[Mttrinh]

Hi,

we changed the interval of min and max interval =(30 to 50) (not working)

we changed the interval of min and max interval =(20 to 100) (not working)

Not totally sure what you mean by this, can you clarify? What is the min interval and what is the max interval?

Also check out the Accessory Design Guidelines for Apple Devices, under "25.6 Connection Parameters".

[Mttrinh]

What example are you using? Is it unmodified except for the connection parameter?

Which SDK and Softdevice are you using?

[SorenKonekt]

Hello Mttrinh

Connection parameters are set according to Apple's accesory design guidelines.
Min connection interval is 300ms and max is 500ms

we are using soft device 132

Our code is much customized to fit our needs, so I'm sure our HW team has done modifications (or made it from scratch, I'm not sure). 

here is sniffer trace. one with normal disconnect and one with disconnect happening despite device and phone are very near to each other. 

https://docs.google.com/spreadsheets/d/1zdk1QG4YRO6hO3bD8OvXlyyPiJ7sKyVfh9bP5hiPtTE/edit?usp=sharing

it's not easy for me to change IOS since we cannot downgrade it, and we don't have plenty of iphone 6s's lying around (the ones that have the issue)

[Mttrinh]

Hi,

I have taken a look at the sniffer traces that you sent me. I noticed that the trace for the disconnect issue, it seems that the device doesn't go back to advertising normally after the disconnect. Could you try to debug your application and find out where it hangs and what error code this function returns when the disconnect occur?

[SorenKonekt]

yes, i am currently trying to reproduce the issue with a Bluetooth Profiler installed on the test phone. This should enable some more extensive system logging. Will get back to you asap. Thank you!

[SorenKonekt]

Mttrinh

so i reproduced the issue (phone and device disconnects although they are 50cm apart on a table). 

Phone bluetooth profiler system logs are here https://drive.google.com/drive/folders/1fkDzhdO8SILxDQgkYUUUaHPzM1lNbV_H?usp=sharing

And this is the message we see in our app log when the disconnect happens:

2020/01/13 10:23:29:952  BLE service disconnected with peripheral. UUID: 4ACCEE9B-0B3D-1EA1-1ED9-EF3E8A03DEBD. Error description: The connection has timed out unexpectedly.

[Mttrinh]

Hi,

Have you debugged the application on your nRF device? it seems to be stuck and won't advertise after disconnection.

Have you also tried connecting your device with an Android phone with the same connection parameters?