How to set the Bluetooth connection interval via mobile apps

[Matthew K]

Hi, guys. I'm using both nRF5 SDK v17.1.0 and the S112 SoftDevice v7.3.0 with the PCA10056 (Rev 2 nRF52840 board).

infocenter.nordicsemi.com/index.jsp

I used the sd_ble_gap_ppcp_set() function to set the CONNECTION INTERVAL from the nRF52 side.

Q: Does the nRF Connect mobile app on iOS/Android have a feature to set the CONNECTION INTERVAL? How do you do it?

Q: I'm going to create a custom Bluetooth mobile app.

What's the iOS Swift / Android Java or Kotlin function to change the CONNECTION INTERVAL?

Let's say I'm only going to use Bluetooth 5.x supported mobile devices.

[Olaf]

Hi,

for iOS take a look at https://developer.apple.com/hardwaredrivers/BluetoothDesignGuidelines.pdf

Chapter 40.6 Connection Parameters:

The accessory is responsible for the connection parameters used for the Low Energy connection. The accessory should request connection parameters appropriate for its use case by sending an L2CAP Connection Parameter Update Request at the appropriate time. See the Bluetooth 4.0 specification, Volume 3, Part A, Section 4.20 for details.

For Android you could have a look at:

https://stackoverflow.com/questions/21398766/android-ble-connection-time-interval

Answer 3:

Since Android Lollipop API level 21 you can use: requestConnectionPriority() With 3 levels: CONNECTION_PRIORITY_BALANCED, CONNECTION_PRIORITY_HIGH or CONNECTION_PRIORITY_LOW_POWER.

But as you see in the Apple document, the peripheral is the right place to change connection interval parameter.

BR

Olaf

[Matthew K]

Thank you Olaf!

Just to be clear, you mean iPhone mobile apps cannot set the connection interval, right?

[Olaf]

You can't set it for central role apps. You could try to make your peripheral supporting HID profile. https://developer.apple.com/library/archive/qa/qa1931/_index.html

Note: If Bluetooth Low Energy HID is one of the connected services of an accessory, connection interval down to 11.25 ms may be accepted by the Apple product.

Only if the app is acting as a peripheral you can select from 3 values like in Android.

https://developer.apple.com/documentation/corebluetooth/cbperipheralmanager/1393277-setdesiredconnectionlatency