Number of reports per advertising

[Nguyen Trong Tuan]

Hello,

I'm programming nrf52 with SDK17. My application requires to advertise in 1 channel and also scan in 1 channel too. I have done the code. But when I run the code, it contains a problem like this. My advertising interval is 40ms, advertising timeout is 0. After advertise, I switch to scan with scanning interval is 100ms and scanning window is 90ms. With these parameters, my devices only get 1 report packet from 1 channel of other devices, but I got 2 per interval of scanning. Can anyone explain it for me? Oh by the way all of my devices have a same code and parameters as I aforementioned.

I'm looking forward for your reply as soon as possible.

Thanks,

Best regards,

[Kenneth]

I don't quite understand the question, but are your device both advertising and scanning here? In that case I recommend to change the scan interval and scan window both to 10ms, this should reduce the risk of scanning cause advertising to be skipped.

Best regards,
Kenneth

[Nguyen Trong Tuan]

Thanks for your reply. Yes my device can advertise and scan. I get your suggestion but I think the scan interval no less than 20ms right??

[Kenneth]

There should be no problem to set scan window  = scan interval = 10ms.

(I think there may be some limitation that advertisement interval cannot be <20ms, but that is not related here.)

[Nguyen Trong Tuan]

But I really need to know why I got 2 packets when I scan. For more detail, I have 2 devices. Same code same parameters. With the paras I have told you, I think that in 1 period of advertising and scanning I can get only 1 packet. So I wonder is that adv and scan response??

[Kenneth]

I think you should setup an on-air nRF sniffer to see what is actually is on-air, but for now I suggest test with the suggested settings.

Best regards,
Kenneth