A new, free, GUI-based, digital timing diagram drawing software for Windows (and Linux/MacOS via Wine http://www.winehq.org/
Waveme is intended primarily for documentation purposes,
where a diagram can be exported (stored) to an image file (PNG, BMP or TIFF) or a PDF document.
A color diagram can be converted to black-and-white, and stored into a new project file.
Waveme can be used to draw waveforms (signals and buses), gaps, arrows and labels (see attached images).
Highly customizable, with a wealth of keyboard shortcuts.
Google group for questions, bug reports, feature requests, and general discussion:
Waveme is distributed as a single-file executable, it doesn't require installation,
and there are no changes to the registry nor configuration files.
Please note that because it is an executable file, it might be flagged by antivirus programs.
Avoid false-positive, by always confirming with Google's http://www.virustotal.com
Hope you find it useful!