BLE Callbacks: Who Connected? Central or Peripheral

[witc]

Hi,

I am working with the nRF54L15 and I want to use it both as a BLE central and as a BLE peripheral. So, I have two separate source files: one for central and one for peripheral functionality. In each file, I have registered callbacks like this:

Peri:

BT_CONN_CB_DEFINE(peripheral_conn_callbacks) = {
    .connected = on_periph_connected_cb,
    .disconnected = on_periph_disconnected_cb,
    .recycled = on_periph_recycled_cb,
};

Central:

BT_CONN_CB_DEFINE(central_conn_callbacks) = {
	.connected = on_central_connected_cb,
	.disconnected = on_central_disconnected_cb,
	.security_changed = on_central_security_changed_cb,
    .recycled = on_central_recycled_cb,
	.le_cs_read_remote_capabilities_complete = on_cs_remote_capabilities_cb,
	.le_cs_config_complete = on_cs_config_create_cb,
	.le_cs_security_enable_complete = on_cs_security_enable_cb,
	.le_cs_procedure_enable_complete = on_cs_procedure_enable_cb,
	.le_cs_subevent_data_available = on_cs_subevent_result_cb,
};

However, when I connect to my nRF54L15 (acting as peripheral) with a mobile phone, the on_central_connected_cb callback is called instead of

on_periph_connected_cb. (I haven’t been able to test the reverse scenario yet).

Is it necessary to check inside the callback who actually connected, if it is a central or a peripheral? How is this usually handled in Zephyr/nRF Connect SDK? Is there a recommended way to distinguish whether the connection is from a central or a peripheral device in these callbacks?

Thank you.

[Kazi Afroza Sultana]

Hello,

You can use bt_conn_get_info() function to check the connection role. This function fills a bt_conn_info struct, which contains a .role field indicating whether the connection is acting as a central or peripheral. You can look at these (+) RE: [NUS, Bluetooth] bt_conn - Nordic Q&A - Nordic DevZone - Nordic DevZone and (+) nRF Connect SDK Bluetooth Low Energy tutorial part 1: Custom Service in Peripheral role - Getting Started - nRF Connect SDK guides - Nordic DevZone link.

[witc]

Thank you vere much, It helped.

[Kazi Afroza Sultana]

You are welcome. I am glad to know that.