Connect a peripheral always with the same central when an event is produced

RE: Connect a peripheral always with the same central when an event is produced

Vidar Berg — Wed, 30 Dec 2020 08:06:57 GMT

Hi,

1) Our examples already uses a random address by default, and this address is unique to each device (DEVICEADDR). But you can also change to a different address through the sd_ble_gap_addr_set() call once the Softdevice is enabled.

2) You need to pair/bond with the peripheral. The peer manager will then store the ID information to flash.

You can use our nRF connect app on Android or iOS to test with if your central doesn't support bonding yet.

Best regards,

Vidar

RE: Connect a peripheral always with the same central when an event is produced

Juan — Tue, 29 Dec 2020 18:35:11 GMT

Hi,

For the same project, I need to know where I can find information about the following:

1) How to generate a random ID in the central when powering up for the first time
2) How to store in the peripheral the ID received from the central in the first connection

In the example "ble_app_hids_keyboard" it is not clear how to save in the peripheral the ID received from the central.

I have tried to advertise the central in direct mode and it automatically switches to fast mode because it does not find any stored ID


Best regards

Juan

RE: Connect a peripheral always with the same central when an event is produced

Vidar Berg — Tue, 29 Dec 2020 12:26:13 GMT

Hi,

Whitelisting is not required, but it does enable filtering of connection requests at the HW level, which means that connection requests coming from "unknown" devices will get ignored automatically. The other alternative is to implement a custom filtering mechanism at the application-level from the BLE_GAP_EVT_CONNECTED event to see if a known device has connected, and if not, immediately terminate the connection.

The address information needed to populate the whitelist is exchanged during the bonding procedure, and this information is stored persistently in internal flash by the Peer manager module.

It sounds like you can re-use most of the existing whitelist handling in the keyboard example for this. In this example you press button 2 to start advertising without whitelist (when you want to allow a new device to connect).

[quote user=""]In this case, is it necessary to use an external E2PROM to save the ID or is it saved directly to the internal flash?[/quote]

The information is stored in internal flash, and preserved across reboots. The Peer manager module manages the flash storage for you.

Best regards,

Vidar