BLE scan timeout always in multiple of second

RE: BLE scan timeout always in multiple of second

guohui — Mon, 05 Aug 2019 02:39:35 GMT

Oh, I was wrong with the initial post. I was flashing the SoftDevice 6.0.0. With SoftDevice 6.1.1, this issue disappears. Sorry and thank you for your patience.

RE: BLE scan timeout always in multiple of second

guohui — Mon, 05 Aug 2019 02:00:44 GMT

Hi Einar,

So I have tried different ways to verify if this is related to our source code or SoftDevice, but the timeout is always align with seconds. Is it possible that some configurations to nRF52840 internal resources might affect the timing of SoftDevice?

RE: BLE scan timeout always in multiple of second

Einar Thorsrud — Fri, 02 Aug 2019 10:51:41 GMT

Hi,

No, this is a puzzle. I do not believe it is an issue with the SoftDevice itself. I have played around with a central example from SDK 15.3, using S140 version 6.0.1 and using that I have no problem settings can timeouts that are other than whole seconds. Also, this is not an issue I have seen before. I am tempted to believe that it is somehow related to your code.

Did just suddenly see this issue, or did you see it just recently after some modifications? Could there be a memory corruption of some sort (just a shot in the dark)?

RE: BLE scan timeout always in multiple of second

guohui — Fri, 02 Aug 2019 06:01:54 GMT

Hi Einar,

Do you have any idea so far? Or any suggestion that I can try to figure out whether it is something wrong with my own code or the SoftDevice?

Thanks a lot!

RE: BLE scan timeout always in multiple of second

guohui — Wed, 31 Jul 2019 13:28:13 GMT

The above effective parameters are corresponding to the parameters that I set in application, which is:

params.interval = 32;

params.window = 16;

params.timeout = 50;

RE: BLE scan timeout always in multiple of second

guohui — Wed, 31 Jul 2019 13:12:30 GMT

Yes. As the log I posted above, the timeout event is generated right in multiple of second.

RE: BLE scan timeout always in multiple of second

Einar Thorsrud — Wed, 31 Jul 2019 13:08:06 GMT

Hi,

I see. Can you compare it with when you get the timeout event from the SoftDevice? Does that happen after a whole second as well?

RE: BLE scan timeout always in multiple of second

guohui — Wed, 31 Jul 2019 13:03:39 GMT

By measuring the power consumption during scanning, from the current chart I captured, the scan interval and scan window did align with the value that I set in my application, while the timeout always in multiple of second.

RE: BLE scan timeout always in multiple of second

Einar Thorsrud — Wed, 31 Jul 2019 08:55:11 GMT

Hi,

This is odd. I don't see anything that should cause the timeout to be in whole seconds. How have you verified that scanning is in whole seconds? In other words: How do you check how long time the device scans?

RE: BLE scan timeout always in multiple of second

guohui — Tue, 30 Jul 2019 11:46:28 GMT

More code can be found here: https://github.com/particle-iot/device-os/blob/fix/ble/v1.3.1-rc.1/hal/src/nRF52840/ble_hal.cpp#L1230

Thank you so much!

RE: BLE scan timeout always in multiple of second

Einar Thorsrud — Tue, 30 Jul 2019 11:32:50 GMT

Hi,

This is not a limitation of the SoftDevice (BLE stack), so I think we need to see more of your code. It could be for instance that you are doing some integer math that causes this, but that is just a guess without seeing what you are doing.