DDiscovery Logic Analyzer captures bad data

[LarsB]

With my new Digital Discovery logic analyzer, I captured the bus of an electronic device (see attached project).  There are two potential clocks: D15 is the clock for the functionality I want to examine, and D16 is the general READ ACTIVE clock.  For some reason, the saved project shows D16, but doesn't allow D16 as clock for the bus.

In the Event viewer, the bus with clock D15 shows seemingly random data, although almost all data should be in the h4000 to h5FFF range.  Also, there are awfully few entries.  Likewise, D14 shows very little activity.

When I capture the exact same operation with my old Saleae, I get plenty of activity in the above range, with the equivalent clock of D15 (see attached CSV file).  Sample rate of the Saleae was 16 MS/s.

Why the discrepancy?  I triple checked that the connections between DD and probes are correct, on two different days.  Also the probes are correct, and in any case, the DD capture and the Saleae capture was done with the same probes, within one hours.

Right now I seems that either the DD or WaveForms is broken.  If needed, I can happily provide additional data.

[attila]

Hi @LarsB

Do you have GND connection between Digital Discovery and the electronic device ?
Is the Voltage/Threshold correctly set in WF/Supplies ?
I would recommend to use the latest software:
https://forum.digilentinc.com/topic/8908-waveforms-beta-download/

Edited November 4, 2021 by attila

[attila]

Hi @LarsB

Please attach the project and csv if possible.

[LarsB]

Obviously, you have to add attachments to the post, so let me try again.

default.dwf3logic

Oh and now I'm no longer allowed to upload a 9 MB file.  Please get it here:

http://endlos.net/saleae-csv.zip

[LarsB]

Here is the decoded bus data for Saleae, i.e., the hex values that should be displayed in the event viewer for that bus with clock D15:

saleae-bus-data.txt

[LarsB]

To further investigate, I tried to capture only the clock signal by both Discovery and Saleae at the same time.  For that, I soldered an extra wire to the signal pin, and connected Discovery to the pin and Saleae to the wire.

But while Saleae did record activity, I only got 0s in WaveForms:

Here's the workspace with capture:

newtry.dwf3work

I even tried both DIN 0 and DIN 1 in case a wire was bad, but I got the same result.

Also note that the number of samples captured indicate a recording time of about 0.5 seconds, which is shorter that the actual recording time of 1-2 seconds.

The data the Saleae captured:

saleae.csv

I'm not sure what to make of this.  To me, it seems that my Digital Discovery is broken.  Can you suggest anything else to try?  Is a crucial setting wrong?

[LarsB]

Yes, I connected one group wire of the Discovery to ground.

I didn't even know that you need to configure Supplies, but here is the current setting:

Voltage is correct, threshold is fine, pull-down.  I wasn't sure about the strength of the pull-down, so I retried without it, but I still get only 0.

I'll try the beta, though.

[LarsB]

Oh, finally!

At last this is looking as it should be.  I'll try with all 25 signals later, but at least I'm confident now.

Thanks for your suggestions, Attila.