gschem
gEDA/gaf's Schematic Capture
What is gschem?
What does it look like?
Who is the author of gschem?
What is "schematic capture"?
So what can gschem do?
What features are missing from gschem?
Where can I download it?
What is gschem?
gschem is the schematic capture program/tool which is part of gEDA. It's sole purpose is to facilitate the graphical input of components/circuits.
What does it look like?
Here is a page of current screenshots.
Who is the author of gschem?
Gschem is a community effort with several dozen contributors participating in the gEDA Project. The project was originated by Ales Hvezda, and he wrote the original version of gschem.
What is "schematic capture"?
Schematic capture is a fancy name for the ability to draw and layout circuits using a computer. Standard symbols are used to represent the various gates and components which are interconnected by nets (wires). Most vector drawing programs can be used for schematic capture but they usually lack one (or more) of the following characteristics:
- The awareness of the electrical properties of components, nets, and pins.
- Hierarchical design (having components represent some abstracted functionality).
- The ability to associate attributes with nets and components.
- Generate netlists from the schematic.
These are all critical features which are shared by all schematic capture programs. The schematic capture program which is part of gEDA is called "gschem"; it provides support for all above characteristics.
So what can gschem do?
Current features:
- Draw graphic primitives such lines, boxes, text, circles, and arcs
- Take all of the above primitives and group them into a component or part
- Draw electrical elements such as nets, pins, and buses
- The same interface to draw schematics is also used to draw components
- A component library which has the basic schematic symbols
- Components and primitives can be placed, copied, moved, rotated, mirrored, and deleted
- Components can be embedded in schematic sheets (no .sym files required to view the schematic)
- Components can be included in symbol files to encourage symbol reuse.
- Nets can be drawn to interconnect components and other nets.
- Visual indicators show if a net is dangling or connected to another net (or pin)
- Attributes (text which takes the form: name=value) can be attached to any object
- Attributes can be either visible or invisible
- There are several functions to search for, change the visibility of, and autonumber attributes
- Any object can be selected either by a single click or by a selection box
- Multiple objects can be selected and operations can be easily performed on this group
- The display can be zoomed, panned, resized, and redrawn at the touch of a button
- Postscript printing of the schematic is supported
- PNG image writing of the schematic is supported
- All colors and certain object characteristics can be changed via a rc file
- Ability to open multiple windows and work on multiple schematics easily
- Support for multiple buffers/pages/schematic open at the same time
- Support of a stroke like user interface
- Scripting. Uses guile (scheme like language) as its scripting language
- Hierarchical support for schematics and symbols
- Automatic drawing of bus rippers when connecting nets to buses
- And more...
gschem is pronounced like "gee-shhhem" (like the German word Schule) or "gee-skkhem" (like the English word school).
What features are missing from gschem?
Here are the features which are currently missing:
- Automatic net routing around components
- DRC
This list is rather short; gschem has matured to the point where many people are able to use it for challenging designs.