Pairing specific pairs among many

[June20]

Hello, we're trying to make products using BLE with nRF52840(central) and nRF52833(peripheral).

We did make custom boards and also made a program that once paired(bonded), it won't connect with others.

(eg, once nRF52840 and nRF52833 is paired, it will not connect with others)

We were wondering is there a way to make specific central connect with specific peripheral?

Is there a way to make each central/peripheral unique so that pairing process can be done without interference?

We got concerned that wrongly paired(or bonded) devices might ship out.

At our current stage, pairing wrong central/peripheral is possible.

Other infos.

nRF52840-central has 2 buttons, while nRF52833-peripheral has none

We're using SDK 17.1.0 S140 Segger Studio

has NUS(communication) and BAS(battery check) BLE services

thanks

edit:

extra question: is there a way to write certain unique number/MAC address on flash during flash write and then read it during application?

How do I know which address of flash is used or not?(want to avoid  collision with bonded info)

Is there a download tool beside nRF Connect Programmer?

[June20]

The third area at top I was talking about was 0xFD000 ~ 0xFD007 (8byte). I think you're right, Flash Storage - NRF_FSTORAGE_ DEF from info center mentions 0xFD000 address (though mine from fds.c doesn't mention any address). I didn't really used any FDS, is it from SoftDevice?

UICR was very useful, I was able to narrow down to the specific peripheral from BLE central. Since BLE central can use filter, is there a way for peripheral to filter scanners (by ble address/name/etc.)?