+Attributes are key-value pairs attached to objects. The format and content +of both keys and values are free form. Most of the time the meaning of +an attribute is defined by the user and the only code that process +the attribute are user scripts. +
+However, there are a few attributes recognized and parsed by pcb-rnd. This +document lists those attributes. + +
| attr key | object + | description + |
|---|---|---|
| term | drawing primitives, subcircuit + | terminal ID + |
| intconn | terminals (drawing primitives, subcircuit with the term attribute set) + | internal connection + |
| intnoconn | copper objects (drawing primitives) + | break internal connection + |
| noexport | drawing primitives + | do not export the object + |
| refdes | subcircuit + | reference designator; the unique name of the subcircuit instance (also used in the netlist) + |
| extobj | subcircuit + | names the extended object implementation that handles the subcircuit + |
| init-invis | layer group + | the layer group should be inivisible after loading the board + |
+Terminal ID is the unique identifier of a terminal (pin, pad, lead of a part). +Together with the subcircuit's refdes, the terminal ID is used to identify the +terminal on the netlist. Very often matches the datasheet's pin number. + +
+Value is a small positive integer. Terminals within the same subc sharing the +same intconn value are connected within the package, even if terminal IDs differ. +The connection is invisible/implied. Used to indicate in-package connections +(e.g. zero ohm resistor used for an extra layer). + + +
+Value is a small positive integer. Copper objects within the same subc sharing the +same intnoconn value are assumed to have no connection with each other even if +they overlap by geometry. Used to break unwanted connection in a subcircuit, +e.g. to avoid shorts in a 2 terminal antenna or coil footprint. + +
+A drawing primitive that has the noexport attribute (with any value) is marked +on the screen with an overlay X mark and is not exported to any of the +graphical exports. A noexport:exportername attribute will inhibit +the object only from the named exporter (e.g. noexport:png will make +the object disappear from the png export but not from any other exports). +Multiple noexport:exportername can be used. +
+Some side effects of the object will not disappear: +
+The noexport attribute on padstacks will inhibit all shapes (including the slot) +and the hole too. +
+Graphical exports are those that use the central draw mechanism for getting +the drawing primitives generated. Some exporters, typically the ones that +export data (and not drawing) will not call the draw API and thus will ignore +the noexport attribute. + + +