Scanning on Coded PHY and 1M PHY with softdevice Controller

[jonas.woerner]

Hi,

I created an application, that scans on Coded PHY and 1M PHY simultaneously. The problem is, it only works with the Zephyr opensource LL, but not with the Nordic Softdevice LL.

With the Softdevice LL, I dont get any error and it seems like its working, but its only scanning for 1M devices. if I add the SCAN_OPT_NO_1M flag, coded scanning works, but ofcourse no 1M scanning.

these are my scan parameters:

static constexpr struct bt_le_scan_param scanParams{

.type=BT_LE_SCAN_TYPE_PASSIVE,

.options=BT_LE_SCAN_OPT_CODED,

.interval=BT_GAP_SCAN_SLOW_INTERVAL_1,

.window=0x320,

.timeout=0,

.interval_coded=BT_GAP_SCAN_SLOW_INTERVAL_1,

.window_coded=0x320,

};

This seems to be a bug in Nordics LL implementation? Im using sdk 2.6.1.

any help is much appreciated!

Kind regards,

Jonas

[Amanda Hsieh]

Hi, 

Check out my colleague's answer in this post. 

Regards,
Amanda H.

[jonas.woerner]

But the criteria that Hung bui mentioned are obeyed here? Window is less then half of the Interval...

[Amanda Hsieh]

Yes, for the softdevice controller. 

ZLL supports all combinations of varying interval and window simultaneously on both phy, and also simultaneous continuous scanning on both phy. Scanning wraps around other active roles, only when in continuous scanning, I.e. interval equals window. Mix of continuous on one phy and windowed on other phy too is supported, where continuous scanning wraps around windowed scanning.

[jonas.woerner]

yes, I know. But I want to use the softdevice controller... and Im using the correct parameters and its not working? Or what am I missing?

[Amanda Hsieh]

Hi, 

Are you using nRF52840DK? If not, could you test on nRF52840DK?

I think there might be a bug in your code - something that is very easy to miss. BT_CONN_LE_OPT_CODED  is not the same as BT_LE_SCAN_OPT_CODED. The first is for connection establishment, the second one is for scanning.

I tried using the samples peripheral_hr_coded and central_hr_coded in NCS 2.6.1 where I changed the scan parameters and the connection establishment parameters to what the customer wanted (see attached patch 1057.sample_diff.patch). That works as expected. 

If the above doesn't help, please provide the project to investigate the issue. 

[jonas.woerner]

I am using a nRF52840DK. Thanks a lot for testing this, Its Interesting that it works like that. I will try to reproduce your findings and then search for whats propably a bug in my own code then. Will report if I get it solved :)

[stathisv]

I had the same issue when using nRF Connect SDK v1.9.1, ie even by setting the scanning window to less than 50% of the scanning interval it was only scanning 1M PHY devices. However, after I upgraded to v2.6.2 of the SDK it seems to be working as expected. Is it known to be fixed in some version in between?

[Amanda Hsieh]

You can check the release notes for versions between 1.9.1 and 2.6.2.