Nordic BLE scan


Gavrikov Paul <Paul.Gavrikov@...>
 

Hello,
I have a question related to running Zephyr on a Nordic nRF52 DK and BLE:

Using a nRF52-DK2 (pca10040) I want to continously (passive) scan for advertisements, so I set the following params:

struct bt_le_scan_param scan_param = {

               .type       = BT_HCI_LE_SCAN_PASSIVE,

               .filter_dup = BT_HCI_LE_SCAN_FILTER_DUP_DISABLE,

               .interval   = 0x00A0,

                .window     = 0x00A0,

        };

When I look at the energy consuption I see a weird behaviour: The enforced channel switching seems to turn off the radio and restart it every time. Causing a "gap" of different durations. Sometimes such a scan window cannot be established at all before switching to the next channel. This is very different to the implementation of Nordic. Their SoftDevice132 switches channels just like Zephyr but the "gap" between two windows is very short and always of almost the same length (roughly 1.6ms).
Using Zephyr checkout 935d0ce.

Image showing energy profile: https://user-images.githubusercontent.com/9333587/34712922-d97203ee-f524-11e7-8548-3c025b572812.png

Best,

Paul Gavrikov

 

eMail: Paul.Gavrikov@...

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