Bond and then automatically connect. Bond to multiple devices.

[Pedro]

Hi!

I'm developing the software for a central and a peripheral that implement the Automation IO service, to control some GPIOs remotely. I'm using NCS v2.0.2

I need, once they are connected, they bond, central store the information of the bonding, and next time connect automatically. Could you please recommend me some examples or resources to do that?

I guess if I clean the memory of the central or the peripheral, and one side bond information is deleted, they can't connect again, because one side thinks the other side has the bond information, but it hasn't. Am I right? How could I delete the bond information, to do the bonding process again, in this case?

Another questions:

Is it possible for central to bond to multiple peripherals, and maintain the connection and communication with all of them? 

Is it possible for peripheral, once connected to a central, keep advertising to be able to connect to another central, and be connected to 2 centrals at same time?

Any examples?

Thanks and kind regards,

Pedro.

[Kenneth]

Hello,

If you havent already you should check out the BLE fundamentals tutorial:
https://academy.nordicsemi.com/courses/bluetooth-low-energy-fundamentals/ 

If one peer have lost bonding information there are kconfig options that may help, please check out:

Please check out:
https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/kconfig/index.html#CONFIG_BT_ID_UNPAIR_MATCHING_BONDS 
https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/kconfig/index.html#CONFIG_BT_ID_ALLOW_UNAUTH_OVERWRITE 
https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/kconfig/index.html#CONFIG_BT_KEYS_OVERWRITE_OLDEST 
https://developer.nordicsemi.com/nRF_Connect_SDK/doc/2.4.2/kconfig/index.html#CONFIG_BT_SMP_ALLOW_UNAUTH_OVERWRITE 

The softdevice controller can maintain multiple bonds and multiple connections at the same time. I suggest to go through the tutorial and try&study some of the existing BLE central and peripheral examples:
https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/samples/bl.html 
https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/zephyr/samples/index.html#samples-and-demos 

Kenneth

[Pedro]

Hi Kenneth,

Thank you very much for the resources. The CONFIG options you suggested will help me a lot! 

Kind regards,

Pedro.