Updating scan response packet whilst advertising

[Mike Austin (LPI)]

In my application, I'm using the Scan Response Packet to transmit some device related information, rather than requiring Clients to connect to get this.  I'm using NCS v2.0.0 and testing on an nRF52-DK.

I'm using the following to store the scan response information, and I update the information in there whenever it changes.

static struct bt_data sd[] = {
    BT_DATA(BT_DATA_MANUFACTURER_DATA, NULL, BT_GAP_ADV_MAX_ADV_DATA_LEN-2),
};

On first boot up, when I start BLE, I make a call to:

err = bt_le_adv_start(BT_LE_ADV_CONN_LSR_AD, ad, ARRAY_SIZE(ad), sd, ARRAY_SIZE(sd));

That successfully updates the scan response packet.  But if I subsequently attempt to update the scan response packet whilst I'm still advertising, via a call to:

err = bt_le_adv_update_data(ad, ARRAY_SIZE(ad), sd, ARRAY_SIZE(sd));

Then the scan response packet doesn't change.  I'm checking the result of err after this function call, and its returning 0, which indicates that its been successful.

The only way I seem able to get the scan response packet to update correctly is if I:

1. Stop advertising
2. Update scan response packet
3. Restart advertising

Is there a way to dynamically update the scan response packet whilst advertising?  Or do I need to follow the process of stop, update, restart?

Cheers,

Mike

[Mike Austin (LPI)]

A bit of info I should have included:

#define BT_LE_ADV_CONN_LSR_AD BT_LE_ADV_PARAM(BT_LE_ADV_OPT_CONNECTABLE |\
												BT_LE_ADV_OPT_USE_NAME |\
												BT_LE_ADV_OPT_FORCE_NAME_IN_AD,\
												BT_GAP_ADV_FAST_INT_MIN_2, \
												BT_GAP_ADV_FAST_INT_MAX_2, NULL)

[Hieu]

Hi Mike Austin,

I notice that the data field of your Scan Response BT_DATA macro is NULL, however that is where you supply data to the API. That is most likely the problem. I am not sure how you update the Scan Response data like with that setup though?

On my end, I set up as followed and just calling bt_le_adv_update_data() worked. As I started with a non-connectable base, I test without the BT_LE_ADV_OPT_CONNECTABLE flag. I don't think it changes anything though.

static uint8_t mfg_data[BT_GAP_ADV_MAX_ADV_DATA_LEN-2] = { 0xff, 0xff, 0x00 };

static const struct bt_data sd[] = {
	BT_DATA(BT_DATA_MANUFACTURER_DATA, mfg_data, BT_GAP_ADV_MAX_ADV_DATA_LEN-2),
};

...

	while(1) {
		k_sleep(K_MSEC(1000));

		mfg_data[2]++;
		printk("mfg_data = {%02x, %02x, %02x}\n", mfg_data[0], mfg_data[1], mfg_data[2]);

		err = bt_le_adv_update_data(ad, ARRAY_SIZE(ad), sd, ARRAY_SIZE(sd));
		printk("bt_le_adv_update_data %d\n\n", err); 
		if (err) return;
	}

Could you please try it and let me know if it works?

Best regards,

Hieu