BitGen accepts text strings of 1's, 0's and hex digits and converts them to equivalent "pwl" voltage sources for inclusion in netlists for circuit simulation (with SPICE or Spectre, for example). Periodic waveforms (eg, clocks) can be exported as "pulse" voltage sources. Parameters such as rise time, fall time, pulse width and duty cycle can be set on a waveform-by-waveform basis. BitGen is written in Perl with the Perl/Tk toolkit and has an easy-to-use graphical interface.
XCircuit is a UNIX/X11 program for drawing publishable-quality electrical circuit schematic diagrams and related figures, and producing circuit netlists through schematic capture. XCircuit regards circuits as inherently hierarchical, and writes both hierarchical PostScript output and hierarchical SPICE netlists. Circuit components are saved in and retrieved from libraries which are fully editable. XCircuit does not separate artistic expression from circuit drawing; it maintains flexiblity in style without compromising the power of schematic capture.