Created gSchem Symbols (markdown)

gSchem Symbols.md

@@ -0,0 +1,43 @@
+## Procedure
+
+1.  Draw the graphical part of the symbol (lines, boxes, delineation of
+    internal connections)
+2.  Add pins (keyboard shortcut: ap) and fill in the attributes
+    'pinlabel','pinnumber','pinseq','pintype'. Normally, the first two
+    attributes are kept visible while the other two are kept invisible.
+    Use the pin name mentioned in the device datasheet as your
+    'pinlabel'. 'pinnumber' and 'pinseq' have the same value unless you
+    are using [slotting](slotting "wikilink"). 'pintype' should be one
+    of the ten values mentioned in the ![ gEDA Master Attribute
+    Document](geda-attributes-Hvezda.pdf
+    " gEDA Master Attribute Document") and should be in lower case.
+3.  Add at least the following symbol attributes to the symbol:
+    'refdes', 'device', 'value', 'description', 'author', 'numslots' and
+    'footprint'
+4.  Make all attributes invisible (keyboard shortcut 'en') and translate
+    the symbol to the origin using the keyboard shortcut 'et'. This
+    ensures that the symbol appears at the right place when invoked.
+5.  Run [gsymcheck](gsymcheck "wikilink") on the symbol file to ensure
+    it is alright
+
+## Hierarchical Symbols
+
+These are symbols which represent underlying schematics (or netlists).
+There are some additional requirements in this case:
+
+1.  *Source=* attribute pointing to source schematic
+2.  *model-name=* attribute pointing to model name or subcircuit name
+    with parameters
+3.  *file=* pointing to relative path of the sub-circuit prototype
+    (SPICE subckt file)
+
+## Also see:
+
+1.  Some guidelines on the gEDA library page: on
+    <http://www.gedasymbols.org/csv.html>
+2.  See the ![ gEDA Master Attribute
+    Document](geda-attributes-Hvezda.pdf
+    " gEDA Master Attribute Document") for the meanings of the
+    attributes.
+3.  Automated tool for converting schematic to symbol:
+    [geda\_sch2sym](geda_sch2sym "wikilink")