Component symbols (from here on known as "symbols") are drawn
using gschem just like drawing a schematic sheet. Here are the steps in
a symbol in the gEDA/gaf system:
- Run gschem and find a blank page or run: gschem filename-1.sym
- Draw the symbol (see the style guide below for some conventions).
- Translate the symbol to the origin using Edit/Symbol Translate...
- Zoom in at least one step.
- Make sure the snap is ON (this is critical).
- Make sure grid snap size is set to 100 (this is critical).
- Select "Symbol Translate..." or the press equivalent hotkey.
- Enter 0 into the entry field and press OK.
Translating the symbol to the origin is a required step. To translate
a symbol elsewhere, enter a offset (in mils) which is a even multiple
of 100. Make sure all pins are snapped to a 100 mil grid point.
- Save the symbol using Save or SaveAs... Here are some symbol naming
conventions:
- Symbols are named: symbolname-#.sym
- Symbols end with a .sym extension.
- Symbols have a -# where # is a number. Typically # is
1 but if there are multiple symbols for a device then
this number simply increments.
- Symbol names are typically lowercase but letters which
are part of a part number are uppercase.
- The above case rule can be broken if the filename
looks incorrect or wrong.
- Place the symbol in one of the directories specified by the
component-library keyword in the system-gafrc file. Once this is
done, the symbol should be visible immediately and can be selected
and placed with the "Add/Select Component..." menu item.
Ales Hvezda
2005-08-20