Bug 1317

Summary: incorrect data display(?) at high logic channel counts
Product: PulseView Reporter: Gerhard Sittig <Gerhard.Sittig>
Component: Data displayAssignee: Nobody <nobody>
Status: CONFIRMED ---    
Severity: normal CC: soeren
Priority: Normal    
Version: unreleased development snapshot   
Target Milestone: ---   
Hardware: All   
OS: All   
Attachments: demo device, cable squid, 64 channels, unexpected waveforms
demo device, cable squid, 32 channels, waveforms look good

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.