Absolute time synchronization to a trigger

[Loic VINET]

Hi

I would like to know if it is possible to synchronize a trigger with the time of the computer.

my trigger is set with dwf.FDwfDigitalInTriggerSet(hdwf, c_int(0), c_int(0), c_int(1 << channelTrigger), c_int(0))

then after dwf.FDwfDigitalInConfigure(hdwf, c_int(0), c_int(1))

I start the acquisition of the data with dwf.FDwfDigitalInStatus(hdwf, c_int(1), byref(sts))

How can I set a time in nanosecond coming for example in python with time.time_ns() with the time of the trigger?

Ultimately, I would like to plot a signal and have the absolute time in x axis.

 

[attila]

Hi @Loic VINET

The FDwfAnalog/DigitalInStatusTime returns the absolute time of T0.
For AD2 this is software time. For ADP3X50 and newer devices high resolution device timer.

[Loic VINET]

Hi Attila

Thank you for your answer

I run this:

    while cSamples < nSamples:
        dwf.FDwfDigitalInStatus(hdwf, c_int(1), byref(sts))
        dwf.FDwfDigitalInStatusTime(hdwf, byref(psecUtc), byref(ptick), byref(pticksPerSecond))

For the first iteration I had for example:

  psecUtc 1679507688
  ptick 253
  pticksPerSecond 1000

I'm looking for at least 10 ns precision, looks like I have ms precision

Is it possible to get that 10 ns precision?

another question, does it give me the time of the first item of the acquisition at the first iteration?

[attila]

Hi @Loic VINET

On AD1,2 only software timer is available. The returned time stamp when FDwfAnalog/DigitalInStatus was last called.

[Loic VINET]

Hi Attila,

I am using the device "Digital Discovery", what should I do or buy to have a 10 ns precision?

[attila]

Hi @Loic VINET

Now I know you are using Digital Discovery. I'm adding hardware timer for this product. It will be available with the next software version.

[Loic VINET]

Hi Attila,

Fine

2 questions:

1. Do you have any idea when this new software version should be available?
2. By new software, can you confirm you are talking also about the library cdll.dwf on windows or cdll.LoadLibrary("libdwf.so") on linux?

This feature is ultimately very important to us 🙂

[JColvin]

Hi @Loic VINET,

The new software will be available when Attila (the developer of the WaveForms software) gets the opportunity to dedicate the time to create it (the new hardware design to load onto the FPGA and the corresponding WaveForms software to support/take advantage of the feature). He lives in Europe though, so it will be little while before he gets the opportunity to respond to part 2 of your question.

My personal guess (as opposed to an official answer) as a somebody not involved with the development process for WaveForms would be that the update might be available by the end of next week (presuming that other priorities don't take over Attila's time).

Thanks,
JColvin

[attila]

Hi @Loic VINET

1. Hopefully tomorrow, after some testing around the other modifications.
2. Yes.

[attila]

Hi @Loic VINET

For Digital Discovery it returns 1.25ns (DIO/DIN trigger) or 10ns (other trigger sources) resolution absolute time for T0.
The resolution changes when the system frequency is adjusted, 1/(8xFreq) or 1/Freq.
The timer is synchronized with the computer on software connection to the device (FDwfDeviceOpen).

 

[Loic VINET]

Hi Attila,

Thank you for it  and for being so fast.

I will test it as soon as possible, maybe not as fast as you.

 

[Loic VINET]

Hi Attila

Well well well, it works:

psecUtc 1679670100
ptick 418708162
pticksPerSecond 800000000

Thank you I will continue my tests with this new feature.