Bug 1317 - incorrect data display(?) at high logic channel counts
Summary: incorrect data display(?) at high logic channel counts
Status: CONFIRMED
Alias: None
Product: PulseView
Classification: Unclassified
Component: Data display (show other bugs)
Version: unreleased development snapshot
Hardware: All All
: Normal normal
Target Milestone: ---
Assignee: Nobody
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2018-11-03 20:04 CET by Gerhard Sittig
Modified: 2018-11-04 02:53 CET (History)
1 user (show)



Attachments
demo device, cable squid, 64 channels, unexpected waveforms (98.41 KB, image/png)
2018-11-03 20:04 CET, Gerhard Sittig
Details
demo device, cable squid, 32 channels, waveforms look good (94.02 KB, image/png)
2018-11-03 20:05 CET, Gerhard Sittig
Details

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Description Gerhard Sittig 2018-11-03 20:04:12 CET
Created attachment 473 [details]
demo device, cable squid, 64 channels, unexpected waveforms

Using 64 logic channels with the demo device results in an unexpected 
waveform display, while 32 channels seem to work, as does sigrok-cli 
terminal output.

How to reproduce:

See the expected output in the terminal.
  $ sigrok-cli -d demo:analog_channels=0:logic_channels=64 \
    -g Logic -c pattern=squid --samples 200 -O ascii:width=200 | less -S

Compare this to the GUI output:
  $ pulseview -d demo:analog_channels=0:logic_channels=64
  (then "configure probes", set the pattern to "squid", capture 200 samples)

Compare this to the GUI with fewer channels:
  $ pulseview -d demo:analog_channels=0:logic_channels=32

I'm not certain whether it's the data display, or the internal storage of 
received data including the zoom level management inside Pulseview.

IIUC the current Pulseview implementation should support up to 64 channels. 
It's a known limitation that more than 64 channels don't work right now.
Comment 1 Gerhard Sittig 2018-11-03 20:05:08 CET
Created attachment 474 [details]
demo device, cable squid, 32 channels, waveforms look good
Comment 2 Soeren Apel 2018-11-03 23:57:22 CET
What about 33 channels?
Comment 3 Gerhard Sittig 2018-11-04 02:53:59 CET
56 channels still work, 57 don't any longer.  So the limit is higher than 
I initially thought.