Learning About xoscope
Here are my notes about learning to use xoscope a "digital oscilloscope for Linux".
My initial success was to capture the "clock" and "ping" traces seen on my Learning About Skannerz Racerz page.
I constructed a single-channel "probe" from a stereo plug audio cable connected to two alligator clips via a terminal block. I also used a resistor on the positive probe.
@@ TODO: Illustrate and detail probe
The command line invocation I used (see man page or docs for details):
xoscope -1 0 -m 1 -v
Additional support hardware
- One person's xoscope experience -- contains notes including initial probe creation, command line options and setting up line-input capture.
- Question about xoscope and probe creation (Google cache)
- This post about xoscope display speed mentions a patch to fix a hard-coded display update rate, but unfortunately the link is dead:
Put up a new verson which is speed limited to 85 fps (my refresh rate) and only uses abou 6% cpu. If you want to change the fps just go into display.c and change the fps variable to suit. Should make it a command line option I guess. http://home.pacific.net.au/~greendog/xoscope/xoscope-1.8.1.tar.gz
- There is discussion in the INTERNALS document about a related issue and command-line switch "-i" that doesn't seem documented elsewhere:
Next, a limit is placed on how often screen updates occur. The min_interval parameter specifies the minimum interval (in milliseconds) that must pass between screen updates. As explained in the display.c:show_data() function, updates at the end of the trace will be performed more frequently to insure that partial traces are not drawn on the screen. The default min_interval is 50 milliseconds, corresponding to a 20 Hz update rate, and can be adjusted using the command line switch '-i'. A good way to both test this code and see its effects is to specify '-i 1000' which decreases the update rate to a clearly visible 1 Hz. If this code isn't working right, the net result is the X server consuming all the CPU's available time.
- Some discussion about the xoscope buffer circuit in a thread about an Atmega-based oscilloscope.