Two connections between nRf52832 device and a single smartphone

RE: Two connections between nRf52832 device and a single smartphone

Aleksander Nowakowski — Tue, 27 Jul 2021 13:18:02 GMT

Hello Erikk,

Both Android and iOS support both multiple connections and can handle a bi-directional connection to a single device. You may, actually, try it quickly using nRF Connect for Android. First, set up the GATT Server Configuration on the phone to match the configuration required by your device. Then connect to your device (I assume it's advertising?). nRF Connect will connect to it and will receive connection request to the server. You will see all event in the log. From CLIENT tab you may send messages to the device, and from SERVER tab you may use the phone as peripheral (setting readable values, sending notifications, etc.). You may actually have it in 2 different applications. Or more. E.g. nRF Connect can be connected bi-directionally while you're connected in both your apps. The "single physical connection" means, that the mobile phone is managing the connection and is sending any data that any app requests. Each app may have a single or even multiple BluetoothGatt object, which are seen as virtual connections.

Such bi-directional communication is also supported in our Android BLE Library since version 2.2.

I don't know how does it work from the peripheral side. Is the mobile visible with one MAC address, or two. There are samples of it both in NCS and nRF5 SDK, however on mobile side we currently don't have any sample demonstrating bi-directional communication other than some documentation on above-mentioned library.

RE: Two connections between nRf52832 device and a single smartphone

pressure_sensor_nonconn_adv — Tue, 27 Jul 2021 09:36:45 GMT

Hi Amanda,

Kenneth stated in the linked post that: "Apps can have multiple "virtual connections" to the same peripheral."

Wouldn't that mean that we can have two connections (just virtual ones)?

This would also correspond to what was observed. Namely that the phone uses two MAC addresses and two connection handles are given to the application by the softdevice S132.

Thank you for your help and kind regards.

RE: Two connections between nRf52832 device and a single smartphone

Amanda Hsieh — Tue, 27 Jul 2021 06:48:05 GMT

The link is fixed. Post again here https://devzone.nordicsemi.com/f/nordic-q-a/60845/nrf-connect-multiple-connections-to-same-peripheral/247558#247558

RE: Two connections between nRf52832 device and a single smartphone

Erikk — Mon, 26 Jul 2021 14:33:18 GMT

I think the link to the indicated post is broken...

RE: Two connections between nRf52832 device and a single smartphone

Amanda Hsieh — Mon, 26 Jul 2021 12:44:34 GMT

(Updated)

After confirming with our apps expert, I corrected the answer.

Hi Erikk,

Q1. It is possible.

Q2. You can refer to our Android BLE Library which supports bi-directional communication. For the device, you can refer to nRF5 SDK LE Secure Connections Multirole Example which can act either as a Peripheral or as a Central.

Q3. Yes.

-Amanda H.