ISIS Schematic Capture
ISIS lies at the heart of the Proteus system, and is far more than just another schematics package. It combines a powerful design environment with the ability to define most aspects of the drawing appearance. Whether your requirement is the rapid entry of complex designs for simulation and PCB layout, or the creation of attractive schematics for publication, ISIS is the tool for the job. 
A copy of ISIS is included with all Proteus VSM and Proteus PCB Design products.
The following features are provided by ISIS:
Provides total control of drawing appearance in terms of line widths, fill styles, colours, fonts etc.
Modern user interface with dockable toolbars.
Mouse driven place, edit, move and delete for maximum speed of design entry.
Object oriented editor with automatic wire routing and dot placement or removal.
Comprehensive device libraries; device creation & editing is carried out directly on the drawing.
Integrated preview of PCB footprints.
2D drawing capability with symbol library.
Hierarchical design with parameterisation of sub-circuit component and property values.
Full support for buses including sub-circuit ports and device pins.
Free format textual component property lists with global editing and external database import.
Netlist formats : Labcenter SDF, SPICE, SPICE-AGE, Tango, BoardMaker, EEDesigner, Futurenet, Racal, Vutrax and Valid.
Electrical Rules Check and user configurable Bill of Materials reports
Output to any Windows printer device including plotters and colour printers. 
Graphics export for Desktop Publishing via clipboard or to Windows bitmap, Windows metafile, DXF or EPS file.
Draw Schematics Like You See In The Magazines
Traditionally, professional schematic capture packages have paid little attention to how the drawing actually looks when you print it out. ISIS changes all that - now you can choose exactly what colours, line widths fills and fonts will be used for every aspect of your drawings. You can even choose the size and shape of your junction dots! This makes ISIS ideal for use in 'illustration' applications - be it reports, tutorials, project work, books, magazine articles or whatever. And being a Windows application, transferring the diagrams to other applications is just a matter of cutting pasting through the clipboard.

ISIS Schematic Capture

Screen shot showing a typical ISIS design.

Full control of the design appearance is possible through the use of global and local styles.
Component Libraries
ISIS comes with libraries for TTL, CMOS, ECL, Microprocessor, Memory and Analogue ICs plus libraries with hundreds of named Bipolar, FET and Diode discrete semiconductors. There are over 8000 parts in total. These libraries also contain default properties for PCB packaging and simulator models. Both homogenous and heterogeneous multi-element devices are supported so you can place a relay's coil and contacts on separate parts of the drawing. Connector pins can also be distributed. Device editing is performed directly on the drawing using the general editing tools. Devices may be constructed from lines, boxes, circles, arcs, text and special pin objects. Non-electrical symbols may also be created for use in small mechanical or block diagrams.
PCB Packaging Tool
ISIS integrates closely with ARES - the Proteus PCB Layout tool. PCB Footprints may be selected directly from the ARES libraries, whilst pinout information for new devices can be entered using the Visual Packaging Tool.

ISIS Schematic Capture

The Visual Packaging Tool greatly simplifies the process of assigning pin numbers for new components.

Pin numbers for multiple gates, bus pins, pin swap and gate swap can all be specified via this dialogue form.

Hierarchical Design
This feature allows you to represent your design as a block diagram at one level and then define the internals of the blocks on separate 'child sheets'. As well as improving readability, this can save much time if a block is used several times, and then has to be changed. ISIS takes this one step further, and allows the component values within blocks to be specified as parameters on the parent sheet. For example, a block for a low pass filter might be defined with its frequency as a parameter. Several different instances of the filter block could then be placed, each with a different corner frequency.
ISIS supports bus wires, terminals, module ports and device pins. This makes it ideal for handling complex microprocessor designs in which some devices may have over 400 physical pins. Tedious editing is avoided by drawing each of the address and data buses as a single pin. Bus terminals and module ports allow bus interconnections between sheets and hierarchy levels to be quickly specified. 8051 With Bus Pins

An 8051 microcontroller from the 'micro' library with bus pins for the address and port pins. The bus pins of the device are connected to bus terminals.
Property Management
Each component in the design carries a list of properties. Some of these are used to specify PCB packages and simulator models. You can add other properties for your own purposes - stock and order codes are a common example. These properties can be individually hidden or shown as required so as not to clutter the schematic.
A set of global editing tools is provided to permit the selection of groups of components according to their properties, and the manipulation of the properties of the selected group. An operation such as changing all the BC108s to BC109s thus becomes quite simple. Components initial properties come from assignments made when the library part was created. The ASCII Data Import (ADI) feature allows you to import additional properties from ASCII text files using simple matching rules to determine which components are assigned which properties and all properties are available in the Bill Of Materials report.
When you create a new library part you can specify the new part's properties and default values as well define each property in terms of a full description, its type (string, integer, filename, etc.), whether the property should be shown, is editable, etc. ISIS uses this information so that when the part is used in a schematic and edited, each property can have its own field on the 'Edit component' dialogue form with ISIS taking care of validation of the property. For example, if a Zener diode model requires a value for the breakdown voltage, the BV property can be added, given a default value of, say, 5.6V, given a full description such as 'Zener Breakdown Voltage', and be restricted to positive non-zero values. This property will then be allocated its own field on the 'Edit Component' dialogue form, and users of the model will know exactly what parameters are required in order to use the model.
Edit Component Dialogue Form Edit Component dialogue form for a 74LS123.

The form contains a number of property fields including simulation properties, PCB footprint selection and, at the bottom, two user-added fields for stock-code and part-bin location. These last two properties are not included as standard but are easily added and, as is shown, merge seamlessly with existing properties.
Report Generation
The Bill of Materials report can include any of the properties assigned to the components in the design and ISIS lets you define the exact format of the report. Furthermore, it is possible to total up numeric properties for costings and so forth. The Electrical Rules Check (ERC) report provides a summary of common design errors such as shorted outputs and undriven inputs.
Device Drivers
Proteus uses standard Windows drivers to output to both your screen and printer. Both colour printers and pen plotters are supported. Hard copy devices are well catered for and output can be scaled or rotated as required. For example, an A1 sized drawing can be rendered at 1:1.5 sideways on a wide carriage printer. Additional commands provide for copying the schematic to the clipboard and for output to Windows bitmap (BMP), Windows metafile (WMF), HPGL, DXF and EPS graphics files.