nrf52-ble-app-uart-relay does not connect with IPhone

[Faisal Amin]

Hi,

I am working with nrf52-ble-app-uart-relay example following this link,  https://github.com/NordicPlayground/nrf52-ble-app-uart-relay using nRF5 SDK version 16. 

I am able to connect my device (nrf52840 with ble-uart-relay example) with any Android device but not with I Phones. 

The UART-relay device appears when scanning with NRF-connect app but its not connecting (become stuck on the connecting screen). 

I am using NRF-Connect official app on both phones (android and iOS). 

However, I have successfully tested other code examples with IPhone without any issue

Example codes tested:

1. ble_app_hrs_rscs_relay

2. ble_app_uart

3. ble_app_hrs

Therefore, I think the problem is specifically with "nrf52-ble-app-uart-relay example".

Kindly help me out in this regard.

Thanks 

[Simonr]

Hi

Usually, when an applications work with other phones than iOS, it's due to the iOS' strict limits on what it allows for in a connection. The connection interval and MTU sizes being the most common culprits. You can try tweaking the min_conn_interval to 25 ms, as well as lowering the NRF_SDH_BLE_GATT_MAX_MTU_SIZE and NRF_SDH_BLE_GAP_DATA_LENGTH config to 181 and 184 respectively, as I think those are the values set in iOS that it is allowed to connect to. If that doesn't help, are you able to see any kind of logging information on the phone side that might give us an idea of what exactly is going wrong on the phone side.

Best regards,

Simon