Hello!
We experience problems trying to connect from Samsung Galaxy A5 (2017) to BL652-SC-01 module that runs serialization on a custom board: the smartphone is stuck at connection stage being unable to discover services. The application runs on STM32F407 chip. On most mobile devices (we've tested about 20 smartphones running both iOS and Android) connection as well as data exchange works well. We've have some performance problems on some Android devices but in general all they are able to connect, discover services/characteristics and read/write data.
To make sure that problem is not in serialization port nor in the application we've flashed HRM examples from SDK to another custom board based on NRF52832 chip. When we flash example from SDK 13.0.0 the smartphone couldn't connect just like before. In the meantime, there is no connection issue with the same example but from SDK 14.0.0.
We're working with SDK 13.0.0 and SoftDevice S132 v4.0.2. We have already made a decision to upgrade BLE module and SDK to the 14.0.0 but want to know what is possible reason that Galaxy A5 is not able to connect?
I've attached sniffer log. You can find connection request in the frame #483. In our opinion the possible reason might be in channel mapping: we've noticed that other smartphones such as iPhone 4s and Samsung Galaxy A3 in connnection request have all 37 channels enabled while A5 sends in request only several channels.
