note: on the internet I found existing tools for using an rtlsdr and
   things like an arduino as logic analysers.
   with a chip to multiplex things I could possibly breadboard a small
   system that would plot the behavior of every bus line from a system by
   toggling its power and walking the chip.
   the first logic analyser project I found was "sigrok": [1]sigrok.org
   this might log from an
   rtlsdr: [2]https://github.com/Iskuri/RTLSDR-to-Pulseview
   the gui might then be done with some kind of sigrok tool.
   [the feedback steps between logging and the gui might be too slow to
   upsample the input using phase information. there may be a pair of
   tools that are hackable together though.]
   [it's a little sad to use rtlsdr without improving tooling around
   existing frameworks, but we do badly need logic log]

References

   1. http://sigrok.org/
   2. https://github.com/Iskuri/RTLSDR-to-Pulseview