Re: Format of HCI LE Advertising Report Event

[Johan Hedberg <johan.hedberg@gmail.com>]

Hi Michał,


> On 23 Jan 2019, at 12.24, Michał Lowas-Rzechonek <michal.lowas-rzechonek@silvair.com> wrote:
> I've been reading Bluetooth Core spec v5.0, looking for a way to
> optimize sending LE Advertising Report events through HCI.
> 
> It turns out that spec allows concatenating a few reports into a single
> HCI frame: 7.7.65.2 says that "The Controller may queue these
> advertising reports and send information from multiple devices in one LE
> Advertising Report event. So far, so good.
> 
> The question I have is about the exact format of this event. Wording and
> tables in the spec suggest that fields from concatenated reports should
> be interleaved in the HCI frame, that is for num_reports = 2, fields
> should be ordered as follows:
> 
> event_type[0]
> event_type[1]
> address_type[0]
> address_type[1]
> address[0]
> address[1]
> length[0]
> length[1]
> data[0]
> data[1]
> rssi[0]
> rssi[1]
> 
> I don't this format is "natural", if I were to choose I would rather
> simply concatenate a few reports.

See Vol 2, Part E, section 5.2 (page 728 in the pdf):
“
• Arrayed parameters are specified using the following notation: ParameterA[i]. If more than one set of arrayed parameters are specified (e.g. ParameterA[i], ParameterB[i]), then, unless noted otherwise, the order of the parameters are as follows: ParameterA[0], ParameterB[0], ParameterA[1], ParameterB[1], ParameterA[2], ParameterB[2], ... ParameterA[n], ParameterB[n]
“

Johan