what does sd_ble_gap_adv_set_configure do with the buffer to ble_gap_adv_data_t?

[srony]

Hi, I am developing a SDK 17.0.0 based iBeacon application, and I see below API for initializing/updating advertising data.

I want to know what does it do with the buffer?

If I update the data in the buffer directly and not invoke this API, will the BLE engine update the advertising data?

If sd_ble_gap_adv_set_configure is called with the same buffer for updating with initializing, why does it return error?

Do I have to use 2 buffers to update advertising data?

 

uint32_t sd_ble_gap_adv_set_configure	(	uint8_t *	p_adv_handle,
		ble_gap_adv_data_t const *	p_adv_data,
		ble_gap_adv_params_t const *	p_adv_params
	)

Thanks,

srony

[srony]

srony said:

If I update the data in the buffer directly and not invoke this API, will the BLE engine update the advertising data?

With my experimentation, the BLE engine does update advertising data after the encoded buffer updated, even without this API invoking.

[Vidar Berg]

The appropriate or intended way to update adv. data on the fly is to pass a new buffer to sd_ble_gap_adv_set_configure(). Here's from the API documentation (ble_gap_adv_data_t)

GAP advertising data buffers.

The application must provide the buffers for advertisement. The memory shall reside in application RAM, and shall never be modified while advertising. The data shall be kept alive until either:

• BLE_GAP_EVT_ADV_SET_TERMINATED is raised.
• BLE_GAP_EVT_CONNECTED is raised with ble_gap_evt_connected_t::adv_handle set to the corresponding advertising handle.
• Advertising is stopped.
• Advertising data is changed. To update advertising data while advertising, provide new buffers to sd_ble_gap_adv_set_configure.

[srony]

Thanks Vidar, now I totally understand about the updating advertising. One more question, "new buffers to sd_ble_gap_adv_set_configure" is just to ensure the updated packet to be transmitted without CRC error on the fly, right? In fact, for my application, if no stability (eg. system crash, halt, hung or reboot) issue happened, one CRC error packet is not a problem, so is it safe to go on using only one buffer for updating advertising packet?

Thanks,

srony

[Vidar Berg]

I guess it might be ok to just use one buffer. Maybe the only risk is that you may see corrupted adv. packets from time to time. However, there is no guarantee that it can't lead to other issues as the implementation is not designed or tested for this.