Using Electric 3-1: Facets

# Chapter 3: HIERARCHY

| ## 3-1: Facets |

As the introductory examples showed, hierarchy is well supported in Electric. A collection of nodes and arcs is called a facet, and instances of facets can be placed in other facets. Thus, Electric still manipulates nodes and arcs, but the nodes come in two forms: primitive and complex. Primitive nodes are found in the component menu and are pre-defined by the technologies. Complex nodes are actually instances of other facets, and are found in libraries.

Besides organizing facets into a hierarchy, Electric also organizes facets according to their view and version. A facet's view describes its contents (for example "layout", "schematics", "netlist", etc.) A facet's version defines its design age. Each facet, then, is a version of a view of a cell, and the facet's name describes all of this information: CELLNAME;VERSION{VIEW} where CELLNAME is the name of the cell to which this facet belongs, VIEW is the abbreviated name of this facet's view, and VERSION is the version number of this cell's view. When no version number is displayed, it implies that this facet is the most recent version (has the largest number). Thus, the facet "gate;2{lay}" is more recent than "gate;1{lay}" but less recent than "gate{lay}" (which must have a higher version number, probably 3). |

In this example, there is a library with two cells: "gate" and "latch". In this library are facets called "latch", "latch;1{sch}", and "latch{lay}", all of which are facets of the cell called "latch". The facet "latch" has no view name and is therefore from the "unknown" view of the cell. The facet "latch{lay}" is the layout view of the cell.

To rename a facet's cell, use the Rename Cell... command of the Facets menu.

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