Timer synchronous using Precision Time Protocol

RE: Timer synchronous using Precision Time Protocol

Einarh — Mon, 21 Mar 2022 12:56:23 GMT

I would recommend looking over the code in this MPSL timeslot sample to see how the timeslot API in NCS is used.

-Einar

RE: Timer synchronous using Precision Time Protocol

HaoHuang — Tue, 15 Mar 2022 07:57:08 GMT

Actually,I think taking the time slot example is more reasonable,I think I will put more attention on this approach.By the way, Although the the example use the nRF5 SDK but the the controller is softdevice controller which is same as the NCS example I use.

What part or what's the API should I replace? Could you please point this out to me?

Best regards,

hao

RE: Timer synchronous using Precision Time Protocol

Einarh — Mon, 14 Mar 2022 14:56:27 GMT

Just to clarify I assume you are only implementing something similar to PTP since PTP is developed for Ethernet networks?

What API are you planning to use to send your packets?

Depending on what you're using your best bet might be to make a timestamp with something like k_uptime_ticks right before you send your packet.

-Einar

RE: Timer synchronous using Precision Time Protocol

HaoHuang — Mon, 14 Mar 2022 04:26:18 GMT

Thanks for your kindly reply! The example you post is what I am referring to,In our use case,we want to calculate the packet latency from sender's application to receivers's application, so we retrieve time_stamp1 (t1) at app of sender and t2 at app of receiver. To get t2-t1 as transmission latency,the timer(or clock) at each side should be synchronized or in other word we need to know the offset of two timers.

As a beginner, modifying the example using the Timeslot API for NCS is quite difficult for me,is there any sample code for NCS can approach this,I really need this,thanks a lot !!!!

Best regards,

hao

RE: Timer synchronous using Precision Time Protocol

Einarh — Tue, 08 Mar 2022 10:18:45 GMT

Hello!

Is this the example using the Timeslot API you're referring to?

In case you weren't aware, there's also a newer Timeslot API for NCS, with a sample found here.

The post you linked to doesn't seem to refer to an API, but suggests altering the Zephyr source code directly from what I can see.

The SoftDevice controller is not open source, so that's not an option in this case.

You'll have to talk with the Bluetooth controller either through Zephyr's Bluetooth Host API, or through nrfxlib's MPSL library.

Best regards,

Einar