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===== Hierarchy =====

When a design has several repeating subcircuits, it can sometimes be useful to draw a schematic for the subcircuit, and then include that subcircuit multiple times in the design.  This creates a //hierarchy// of circuits.

Subcircuit schematics are searched for in a //source library//, and use the "in-1" and "out-1" symbols to indicate which nets to make available as connections for the schematics that include them.  Each subcircuit has a symbol, which uses "''source=''" [[attributes]] to specify the subcircuit's schematic pages.

<note tip>See [[config|Configuring gschem]] for details of how to control where gschem looks for subcircuit schematics.</note>

To add a subcircuit to a schematic, simply place the symbol representing it as a [[components|component]] in the schematic as usual.  Subcircuits can in turn contain other subcircuits!

To view the underlying schematic for a subcircuit component, [[selecting|select]] it and use **Hierarchy→Down Schematic**.  Once finished editing the subcircuit's schematic, use **Hierarchy→Up** to return to the original schematic.