How to avoid ble_advertising_advdata_update?

[Alex Co]

Hi

Currently I have a firmware based on template project for nrf52 (sdk15). I am interested in broadcast data, hence I used ble_advertising_advdata_update() in order to update the broadcasted data frame.

It works nicely, however the device is broadcasting more data than I use at the central device such has flags device name etc. (peripheral is also connectable!)

Assuming that I want to use the **minimal** number of bytes during advertisement in order to save as much as energy (I known against the standard) how can I directly update broadcasted data buffer without using the typefied ble_advertising_advdata_update function?

Image I just want to broadcast 6 bytes:

0x41,0x42,0x43,0x44,0x45,0x46

Can I access the underlying broadcasted buffer and write that data without providing dev name, flags, etc?

Note: I completely control the central devices in terms of software hence I dont need to strictly folow the standard (right?)

Thanks

Alex

[ovrebekk]

Hi Alex

The SDK advertising module is simply wrapping the sd_ble_gap_adv_set_configure(..) call in the SoftDevice, and as you can see from the documentation the SoftDevice will not accept an advertise packet that doesn't follow the specification. The flags field is also required. 

If you don't need BLE compliance couldn't you simply run a proprietary protocol, allowing you full control over all the payload content?

Best regards
Torbjørn

[Alex Co]

I know about gasell protocol but that is my second option. Bluetooth is great because we can use a tablet or smartphone and configure or  solve things...

What is the minimum bytes requered for sd_ble_gap_adv_set_configure(..)  accept request? Flags and size? 3 bytes?

Thanks

[awneil]

Alex Co said:

Bluetooth is great because we can use a tablet or smartphone

But only if you stick to the specs!

[Alex Co]

I am sticking to the specs in terms of "connection" features but trying to save as mush as possible bytes when "broadcast oriented".

[ovrebekk]

Hi Alex 

Alex Co said:

What is the minimum bytes requered for sd_ble_gap_adv_set_configure(..)  accept request? Flags and size? 3 bytes?

That is my understanding, yes. 3 bytes for the flags (type, length and value). 

Best regards
Torbjørn