Unable to obtain repeatable scan response data.

[Sam273]

 Unable to obtain repeatable scan response data.

I can obtain advertising data and scan response data from 3rd party devices. I can obtain advertising data from my server repeatably, but when I try and obtain scan response data from the server I only receive it  once in a 20 minutes period.

I can see consistent scan response data from other BLE devices around.

I have access to both client and server. 

The server is configured as :

 

The client sets up to :

 

 

I print both the scan and advertised data.

I then call scan resume continuously to scan for devices (without the scan parameters).

[Edvin]

Hello,

What SDK are you using?

Are you sure that your device has advertising response, and that you are not picking up advertising packets from another device nearby with scan response? Check the address of the device.

Are you sure your device is not resetting? (encounters an error)? Can I see the messages you get when you use NRF_LOG_DEBUG()? (I assume LOG_DEBUG() uses this).

[Sam273]

Hi Edvin,

I'm using SDK 15.2

Currently for debugging I just have a infinite loop of searching for devices - scan and advertising data..

I'm printing any advertised data by printing the UUID - this is working fine as im seeing my and other devices (I can connect to my device with this data)

I'm printing any scan response data - I am seeing a variety of devices, garmin, Versa, LE-reserved, ect

and the scan response data from my device - I am not/ rarely it seeing. 

If i do find a scan response data from my device i check the address i came from to check it matches with the advertised data found. 

Thanks, 

Sam

[Edvin]

If one of the devices LFCLK is off, then the timing of the scan response would be off, and the scanner may not pick it up correctly. Since you were able to pick up the scan responses from the other devices frequently, it may suggest that your peripheral's LFCLK was off, sending the scan responses at the wrong time, outside the window when your central was scanning.

Is it possible for me to recreate your issue? Is it possible for me to reproduce this with two DKs?

From your sniffer trace,  is that the scan response that you received? Does it look the same the next time, when you don't get the scan response?

BR,

Edvin

[Sam273]

The data on the sniffer is quite consistent Irrespective of whether scan response was received or not.

I get a scan request every 180ms but that can be as high as 580ms or low as 16ms. Around 3 responses are missed every 20 requests. if the peripheral responds it is within 4 ms. 

[Edvin]

Does this only apply for this peripheral's scan responses?

You say that you can receive other peripherals' scan response, correct?

What is the advertising interval of your peripheral, and what is the scan interval and scan window on your central?

[Sam273]

The above sniffer image is what the peripheral is seeing, showing that it is getting scan request from the central Mac address 66:0b... and the peripheral responses with a scan response. It is that scan response that my central can't see in software. (I have seen a response in my software occasionally after long periods of scanning, upwards of 10 minutes.)

Yes I can see scan response data from other peripheral consistently  in my software.

Central & peripheral settings are the same :

scan interval = 160 = 100ms

Scan duration = 0 = Infinite 

Scan window = 80 = 50ms

Min connection interval = 7.5ms

Max connection interval =  7.5ms

[Edvin]

Perhaps you can try to hack another central example. In the advertising_report event, just set a filter on the address that you know is correct and print something every time you receive an advertisement and every time you receive a scan response.

I tried to open your project, but it says:

Other than that, I don't understand why it shouldn't work in your project. But again, it is difficult to follow the project and your state machine from looking at the main.c file.