CC1352R: What is the time delay between the absolute trigger time and the actual frame transmission (from the beginning of the preamble)?

Please explain how you are measuring this 90 us time gap (what do you use as an indication of the absolute trigger time?)

Siri

Hi Siri

Take a look at this answer:
e2e.ti.com/.../646759

> Please explain how you are measuring this 90 us time gap (what do you use as an indication of the absolute trigger time?)

As I wrote in the original post.
I’m setting up an initial one-way time synchronization between two nodes.
This time gap is a difference between the same timeslots on the clock source and the clock receiver side just after one-way time synchronization.
The time gap between timeslots is measured using an oscilloscope and the frame transmission is captured via routed PINs.
PINCC26XX_setMux(pinHandle, IOID_5, PINCC26XX_MUX_RFC_GPO3); // GPO3 - high while transmitting
No LBT procedure is used so the time error is deterministic.


/Adam

Sorry, but I still have problems understanding what you are referring to when talking about "timeslots on the clock source" and the "clock receiver side".

You are also not saying anything about how you are doing synchronization.

It would help if you can provide some kind of figure/timing diagram where you show what you are doing in the code, and where you are measuring.

It isn't even clear to me if the 90 us gap you are referring to is between a signal on the TX and a signal on the RX or between signals on the TX side.

I also recommend that you take a look here and see if that answers any of your questions:

Siri

Siri

I think you missed the point.
You are concentrating on the 90us time gap but the question in the post was clearly stated.
Can we go back to the question?

Question was:
What is the time delay between the absolute trigger time and the actual frame transmission (from the beginning of the preamble)?
I'm using CMD_IEEE_TX command.

There is a magic parameter "startToTXRatOffset" mentioned once in the manual which probably is responsible for this time delay.

Simply, I send frame using CMD_IEEE_TX command and absolute trigger time X. This particular command is sent 90-100us later than the scheduled time.
Why is it so?
How can I control this time gap value?
Is this additional time present only in IEEE commands?
Are other than IEEE commands send at a scheduled time?

/Adam

I did additional tests.
I send frame using:
rfc_CMD_IEEE_TX_t TRONIX_cmdIeeeTx = {
         .commandNo = CMD_IEEE_TX,
         .startTrigger.triggerType = TRIG_NOW,
         .startTime = X
};

I read actual send time using:
TRONIX_cmdIeeeTx.timeStamp

Values are as follows:
scheduled time: 19769705 timestamp: 19770089
scheduled time: 23769705 timestamp: 23770089
scheduled time: 27769707 timestamp: 27770091
scheduled time: 31769707 timestamp: 31770091
scheduled time: 35769706 timestamp: 35770090

Assumptions:
There is no LBT procedure.

Conclusions:
The frame is sent ~380 RATs (95us) later than the scheduled time.

Why is it so?

/Adam

Hi Siri

Thank you for your assistance.
This is the answer I was looking for.

/Adam