Setting the BLE Public Address on nRF5340

[Capn Odin]

I am trying to set the public ble mac address from the application core of a nRF5340, I understand that I need to use bt_ctlr_set_public_addr() but I can't seem to get my project to compile when I include bluetooth/controller.h, due to the source file that defines bt_ctlr_set_public_addr() not being added to the project. I am using the SoftDevice currently that is CONFIG_BT_LL_SOFTDEVICE. So my question is what configurations do I need to set to make this work? I have also been thinking that it might be that it is only possible to use the function from the network core, if this is the case then where do I find the source so that I can make the changes that I need or should I instead of change the source use rpc?

If I forgot to mention something important then I apologise in advance.

[Capn Odin]

Sorry that I did not respond sooner but some new priorities came up so I did not get time to look at this before my holiday.

I was stuck for a bit because I had not understood that everything needed to talk with the network core was already in place.

But if anyone else ends up on this page here is how I did it.

main.c

#include <bluetooth/hci_vs.h>
#include <settings/settings.h>
#include <logging/log.h>

LOG_MODULE_REGISTER(ble);
#define REPORT_ERROR(_ERR_CODE_)	LOG_WRN("Error: %d\tFun: %s:%d\tFile: %s", (_ERR_CODE_), __func__, __LINE__, __FILE__)

static char ble_device_name[30];
static bt_addr_le_t addrs[1];

void ble_set_mac(bt_addr_t* addr) {
	struct net_buf *buf;
	int err;

	buf = bt_hci_cmd_create(BT_HCI_OP_VS_WRITE_BD_ADDR, sizeof(*addr));
	if(!buf) {
		REPORT_ERROR(-ENOBUFS);
	}

	net_buf_add_mem(buf, addr, sizeof(*addr));

	err = bt_hci_cmd_send_sync(BT_HCI_OP_VS_WRITE_BD_ADDR, buf, NULL);
	if(err) {
		REPORT_ERROR(err);
	}
}

uint8_t* ble_get_mac() {
	size_t count = 1;
	bt_id_get(addrs, &count);
	return addrs[0].a.val;
}

int ble_advertise() {
	uint8_t* mac = ble_get_mac();
	snprintk(ble_device_name, 30, "%02X%02X%02X%02X%02X%02X", mac[5], mac[4], mac[3], mac[2], mac[1], mac[0]);

	struct bt_data adx[] = {
		BT_DATA_BYTES(BT_DATA_FLAGS, (BT_LE_AD_GENERAL | BT_LE_AD_NO_BREDR)),
		BT_DATA(BT_DATA_NAME_COMPLETE, ble_device_name, strlen(ble_device_name)),
	};

	int err = bt_le_adv_start(BT_LE_ADV_CONN, adx, ARRAY_SIZE(adx), NULL, 0);
	if(err) {
		LOG_ERR("Advertising failed to start (err %d)", err);
	} else {
		LOG_INF("Advertising started");
	}
	return err;
}

void main(void) {
	int err = bt_enable(NULL);
	if(err) {
		LOG_ERR("Failed to enable Bluetooth (err: %d)", err);
		return;
	}
	
	bt_addr_t addr = {{0xFE, 0xCA, 0xA0, 0xAC, 0xDC, 0xBA}};
	ble_set_mac(&addr);

	settings_load();
	
	ble_advertise();
	
	LOG_INF("Bluetooth initialized");
	
	while(true) {
		k_msleep(100);
	}
}

prj.conf

# Config BT
CONFIG_BT=y
CONFIG_BT_PERIPHERAL=y
CONFIG_BT_DEVICE_APPEARANCE=833
CONFIG_BT_DEVICE_NAME_DYNAMIC=y
CONFIG_BT_MAX_CONN=1

CONFIG_BT_HCI_VS=y
CONFIG_BT_HCI_VS_EXT=y

# Config logger
CONFIG_LOG=y
CONFIG_USE_SEGGER_RTT=y
CONFIG_LOG_BACKEND_RTT=y
CONFIG_LOG_BACKEND_UART=n

# Enable Settings
CONFIG_BT_SETTINGS=y
CONFIG_FLASH=y
CONFIG_FLASH_PAGE_LAYOUT=y
CONFIG_FLASH_MAP=y
CONFIG_NVS=y
CONFIG_SETTINGS=y
CONFIG_MPU_ALLOW_FLASH_WRITE=y

[Michael Zeng]

This was helpful to me, so just to add on a bit more:

This code didn't work for me until I added BT_LE_ADV_OPT_USE_IDENTITY to my advertising params.