May peripheral could auto connect to central

[zyj]

Hi all:

          Our usage scenario is to establish a connection and bonded between the NRF52840 peripheral device and the central device, and then restart the NRF52840 peripheral device at this time.  I hope that the NRF can actively connect with the newly connected central device.

   I found this this post ,but i am not sure ,Can I do IT  with 52840 ，52840 is a peripheral in my application ,and central is a smart phone. I want 52840 auto connect to smart phone after they have a connection before.

  Look forward to hearing from you

[awneil]

zyj said:

I hope that the NRF can actively connect with the newly connected central device.

It's not an nRF thing - it's the way the BLE protocol is defined to work.

The peripheral advertises when it is ready to connect - the decision on when/whether to connect is entirely with the Central.

[Karl Ylvisaker]

Hello,

As awneil said, the decision to connect is entirely in the hands of the central, the peripheral will only advertise its presence and the possibility to connect with it. For a smartphone central, you would need to know how the smartphone is configured to handle automatic reconnections.
For this, you should check out Android/iOS specifications on how often their Bluetooth modules behave. For instance, Androids will by default only listen for and autoconnect to their previous connection, if I recall correctly.

Best regards,
Karl

[zyj]

but my sony earphone could connect to my smart phone after it power on ,and i want my NRF  do like this.

why sony earphone could auto connect and NRF can not?

[awneil]

But how that works is that the earphone advertises, the phone sees it, and it is the phone which automatically initiates the connection.

So you need to write your app to do that

[zyj]

get it ! thank you for your kind help!