Will using a whitelist reduce my power consumption scanning on BLE

[tyler]

I have a central device that uses BLE to scan for a specific device (there is only a single device it can bond with). Right now it checks the UUID and the mac address of all peripheral devices it finds and checks if they are correct. I'm wondering what impact switching this to a white list will have. Will it reduce power consumption?

[RK]

Possibly reduce it by an infinitessimal fraction because the whitelisting is done by the softdevice and not by your user code this meaning a very, very few instructions less are executed. In practical terms. No.

[Hung Bui]

I think it actually does reduce your power consumption by using whitelist.

Whitelisting is done by the radio itself, so if you can avoid having the radio and then the softdevice to process the advertising packet and forward to the application an event and then in your application checking out if the address matched or not. It could be much more than just a few instructions. If you have a lot of unwanted advertising packets, it could save good amount of processing time and power consumption of the CPU.

But the radio can't whitelist the UUID though.

[tyler]

Ok. How would I go about white listing a peripheral before it is connected? From my understanding I can set the random static address for the peripheral device (I'm still not sure how). Then I can hard code the random static address into the central device (not sure how to do that either). Is that correct? Can you tell me where to find an example?

[Hung Bui]

Do you have control over both sides of the link (the central and the peripheral) ? If you do, it's not hard to find the static address of the peripheral (default), you can try sd_ble_gap_addr_get() to get the address. To set the whitelist, you use that address you get. You can have a look at this blog here at chapter 3 I have some code showing how to advertise with whitelist. To do scanning with whitelist, it should be similar.

[tyler]

Ok I got white listing working. Now I'm wondering if the power consumption on the central device will go down if I set the advertising type on the peripheral to direct advertising?