Chapter VII: DESIGN ENVIRONMENTS

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Technologies

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A technology is an environment in which design is done. Technologies can be layout specific, for example Submicron MOSIS CMOS, or they can be abstract, for example Schematics and Artwork. Each technology consists of a set of primitive nodes and arcs. These, in turn, are constructed from one or more layers. Each technology also includes information necessary to do design, such as design rules, connectivity rules, simulation attributes, etc.

The library "samples.txt" contains a number of examples of the different technologies in Electric (you can read it with the Readable Dump subcommand of the Import command of the File menu). The table below lists the examples:

FacetTechnologyDescription
tech-MOSISCMOSSubmocmossubSubmicron MOSIS CMOS rules
tech-MOSISCMOSmocmosOlder MOSIS CMOS rules
tech-RoundCMOSrcmosExperimental round CMOS rules
tech-nMOSnmosn-Channel MOS rules
tech-SchematicsDigitalschematics, digitalDigital schematics layout
tech-SchematicsAnalogschematics, analogAnalog schematics layout
tech-PCBpcbPrinted-circuit board layout
tech-DigitalFilterefidoDigital filter architecture
tech-GEMgemTemporal logic specification
tech-ArtworkartworkGraphical design

In general, each technology has three classes of primitive nodes: the pins, components, and pure-layer nodes. The pins are used to join arcs, so there is one pin for every arc in the technology. The components are the basic nodes used in design: contacts, transistors, etc. Finally, the pure-layer nodes are used for geometric manipulation, so there is one for every layer in the technology. The component menu on the left side of the editing window contains arcs at the bottom (these are horizontal layers), pin nodes above that (these appear as boxes with a cross inside), and components at the top (the more complex layer combinations). The pure-layer nodes, which are generally not in the components menu, are available from the New Pure-Layer Node command of the Edit menu. (Note that if you use the Components Menu... command of the Windows menu, and increase the number of menu entries, then the pure-layer nodes will be visible in the components menu.)

When Electric begins, the status area shows the current "Technology". There are, however, many others from which to choose. There are multiple CMOS variations to handle popular design rules such as MOSIS, D.O.D., and even round geometry. A simple Bipolar technology is available. Even Gallium Arsenide technologies have been built into Electric, but since they made use of proprietary design-rules, they are not distributed with the system. There are also abstract design environments such as schematics, artwork, and digital-filter design.

To work with a different technology, use the Change Current Technology command of the Technology menu. This will prompt you with a list of available technologies. Once a choice is made, the component menu on the left will be redrawn to show the primitive nodes and arcs in the new technology. Since each technology has its own overlappable colors, you will also notice a chromatic change in the display. To see a list of primitive nodes and arcs in the current technology, use the Describe Current Technology command of the Info menu. To get a detailed list of layer, node, and arc information in a technology, use the Document Technology command of the Technology menu.

Electric makes no restrictions about mixing components from different technologies. While editing a facet, you can switch technologies and start using new components along side the ones from the former technology. It is up to the designer to ensure that the resulting circuit is sensible.


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