DDiscovery: How to record with sample rate for duration?

[LarsB]

I want to record signals at 10 million samples per second for 5 seconds, but even after perusing the manual I'm at a loss on how to do this.

Apparently, base is not just the displayed duration per screen, but also the recording length, but after the fact?  Setting it to 5 s, and pressing record, 5 s is replaced by 1.6 us?!

And how to I set the sample rate?  I have "100 MHz x 32", but no other setting (unless I enable "advanced view").  With advanced view, I seem to have to compute the duration in my head by dividing samples per rate?!  Although that doesn't work, it seems to record for as long as I want it to.  So what does samples mean?

Also, having a bus with a clock, the data view seems to list every sample, not just the clock-active ones.  Is there any way to achieve this?  What I'd want is a list of values on the bus.

 

[LarsB]

I've just noticed  "list of values on the bus" is covered by the Events view.

[LarsB]

My first capture also isn't quite what I expected.  Look at the TRIG signal in that screenshot:

I zoomed into every blip in TRIG, but didn't find more than two HIGHs each.  Also, the number of events is only 184.

Compare that with the Saleae capture, showing the same signal (for a new run):

You can see that there is a lot of activity going on for slightly more than 3 us.

Why is WaveForms not showing that?  Do I have to configure something special for DIOs >= 24?

Despite that capture problem, WaveForms really has some annoyances.

If you click on one of the signals to the left, the entire line gets highlighted, but it's impossible to get rid of the highlighting -- at least one line will always be highlighted, distracting from the capture for that signal.

While you can save your project, why is WaveForms not automatically loading the most recent project when starting WaveForms?

The zoom in effect is not that great.  Whereas Saleae immediately shows detailed signals when zooming, WaveForms blurs the picture while zooming, making searching for signals much more cumbersome.

And I still don't understand why scrolling and zooming affects both Samples and Rate settings.

[attila]

Hi @LarsB

I will try to answer your questions but let me know if I miss some from your posts.

1. With DD you are using 20MHz sampling rate. If your TRIG is signal rate is higher than 10MHz or pulses shorter than 50ns 5ns it may loose some.

2. Click on other row to change highlighted row or under the last row to remove highlighting.
Use the latest software to have better dark style.
https://forum.digilentinc.com/topic/8908-waveforms-beta-download/

3. Try the latest version and if you are not satisfied with the "zoom effect" please send me a workspace with data.

4. The Repeated mode is intended for oscilloscope like analysis (pulse, phase, timing...) and here the "zooming" adjusts the sample rate.
In Record mode the "zooming" does not affect the rate.

5. In the WF app Welcome tab you can find the last used workspaces.
Check the "Open last workspace on start" it you want this.

Edited October 18, 2021 by attila

[LarsB]

Thank you for your answers, Attila, that clears up all of my questions.

The only issue remaining is the TRIG signal one.  TRIG is HIGH for at least 150 ns and LOW for at least 200 ns, so at 20 MHz or even 100 MHz it should be detected.  But I'll do further testing before reporting back.