Set Bluetooth LE device id (public type) on STM32WBA55

[ivanwagner]

I am looking at the hci_stm32wba.c and hci_core.c sources and I was wondering how and if it is possible to set a public (purchased from IEEE) device id on the STM32WBA55 device. @asm5878 do you have any idea? I've seen that you are a contributor to the hci_stm32wba.c source and I've seen #75176

[asm5878]

Hello @ivanwagner, your point is valid and we have already started to find a solution.

For all STM32WBAX series a public address can be assigned during the initialization of the ble HCI controller.
This the reason why we have used the CONFIG_BT_HCI_SETUP option.

Clearly you can modify the bt_get_ble_add function in order to use the address you want.

But an address stored in flash (and in any case retrieved during the initialization) could be a better solution.
In this way the addresses could be easily customized.

By the way I will check if a standard approach is already present Zephyr.
Do you have any clue on this topic?

[ivanwagner]

I would add an option on zephyr/dts/bindings/bluetooth/st,hci-stm32wba.yaml referring to the flash address where an address can be found. We could e.g. use the OTP region. This way it can be specified via DT. bt_get_ble_add can then check if the option in DT is set, read that location via LL functions and if a valid public address is found, use that as a priority over the current implementation. If no valid address is found it fallsback to the current implementation which is totally fine for development. What do you think?

[asm5878]

After quick check it seems that this problem could be addressed directly at application level.
For instance:

#include <zephyr/bluetooth/bluetooth.h>
#include <zephyr/bluetooth/hci.h>
#include <zephyr/kernel.h>

void main(void)
{
    // Define your IEEE public BLE address (replace with your own)
    bt_addr_le_t my_addr = {
        .type = BT_ADDR_LE_PUBLIC,
        .a = { {0xC0, 0x98, 0xE5, 0x00, 0x00, 0x01} }
    };

    // Create a new BLE identity with the specified public address
    int id = bt_id_create(&my_addr, NULL);
    if (id < 0) {
        printk("Failed to set BLE address\n");
        return;
    }

    // Enable the Bluetooth stack
    if (bt_enable(NULL)) {
        printk("Failed to enable BLE stack\n");
        return;
    }

    printk("BLE address set and stack enabled!\n");
    // ... rest of your application code
}

clearly the address can be retrieved from a specific otp/flash region.
And where this information is stored could be specified by ST or we could give a customer the freedom to choice.

[ivanwagner]

It works. I made some tests yesterday and was calling bt_id_create after bt_enable. Good! Thanks for the support.