How to calculate advertising interval please?

RE: How to calculate advertising interval please?

PingISTL — Mon, 10 Oct 2022 09:04:33 GMT

Thank you, Kenneth

Another question about the periodic advertising, what is the difference between it and normal advertising? They all specify a minimum and maximum interval and can be scanned for an interval. not sure the periodic means here.

Sorry to bother you.

Ping

RE: How to calculate advertising interval please?

Kenneth — Sun, 09 Oct 2022 16:52:04 GMT

[quote user="PingISTL"]I set scan interval and window same, so it always scans. Not sure this is the only way to get interval roughly right?[/quote]

You will be scanning continously now, so unless there is interference or collisions you have the highest possible chance of getting all advertisment packets.

[quote user="PingISTL"]and I wonder what kind of scan interval and scan window it uses in nRF Connect App.[/quote]

Don't know.

Kenneth

RE: How to calculate advertising interval please?

PingISTL — Fri, 07 Oct 2022 07:51:48 GMT

Hi, Kenneth

Thanks for reminder, I changed scan interval and window, and the scanned interval seems to be reasonable now. I set scan interval and window same, so it always scans. Not sure this is the only way to get interval roughly right? and I wonder what kind of scan interval and scan window it uses in nRF Connect App.

Regards!

Ping

RE: How to calculate advertising interval please?

Kenneth — Thu, 06 Oct 2022 16:37:22 GMT

May I ask what you have set the scan window and interval to?

What do you measure and what do you expect?

Kenneth

RE: How to calculate advertising interval please?

PingISTL — Thu, 06 Oct 2022 12:27:35 GMT

Thanks, Kenneth

I understand the random delay, but not sure why peripherals change intervals after programmed, do you mean changes between minimum and maximum specified ? or Do you mean there is no point to measure the interval then?

I would like to do a roughly measurement like nRF Connect App shows. is this possible?

Ping

RE: How to calculate advertising interval please?

Kenneth — Thu, 06 Oct 2022 12:01:17 GMT

Yes and no. Have in mind though the peripheral can change the interval.

edit: and that the measurement might be influenced by a up to 10ms random delay.

Kenneth

RE: How to calculate advertising interval please?

PingISTL — Thu, 06 Oct 2022 10:46:17 GMT

Thank you, Kenneth

So, for a particular peripheral, does this mean I am not be able to measure its advertising interval by scanning two packets and calculate the time interval in between?

Regards!

Ping

RE: How to calculate advertising interval please?

Kenneth — Thu, 06 Oct 2022 10:37:39 GMT

Hi,

A peripheral device can advertise any interval between few ms to several seconds, there is no information in the advertisement packet about how frequently it does the advertismenet. As a central device you can only set a scan window and scan interval and hope for the best.

Kenneth

RE: How to calculate advertising interval please?

PingISTL — Thu, 06 Oct 2022 10:15:10 GMT

Hello, Kenneth

Thank you for reply!

I am not developing peripherals to do periodic advertising, just simply want to scan any peripherals doing advertising, Am I able to follow them if they are not doing periodic advertising? I don't mind random delay of 0-10ms, the interval between packets on UART receiving line is much big than that, so I wonder whether the original interval is lost over the transmission.

For normal peripherals which not doing periodic adverting, there is a minimum and maximum interval specified, does this mean their intervals is random between the specified ?

Regards!

Ping

RE: How to calculate advertising interval please?

Kenneth — Thu, 06 Oct 2022 09:58:18 GMT

Hello,

The intention is to use periodic advertisement feature for this functionality:
https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/zephyr/samples/bluetooth/periodic_adv/README.html

If you want to "follow" legacy advertisment packets, have in mind that in BLE there is a 0-10ms random delay between each advertisment packet as specified by BT core spec.

Best regards,
Kenneth