Using Electric 1-11: Schematics Example

Chapter I: INTRODUCTION

| ## 11: Schematics Example |

This example illustrates the design of schematics. It builds upon the IC layout example and shows how similar editing concepts are used in all environments of design. When drawing schematics, one typically begins by switching design environments. Use the Change Current Technology... command from the Technology menu. Select the "schematic, digital" entry (you will have to scroll down to find it) and click OK. The symbols in the component menu on the left will change to a schematics set. Create a new facet with the Edit Facet... command of the Facets menu, as described before.

Digital schematic elements are available from the component menu on the left. Analog components can be created by selecting the "schematic, analog" technology, but they may also be selected with the New Analog Part command in the Edit menu. Place components in the facet and wire them together. Note that wires are now held to 45 degree angles rather than 90.

One aspect of the And, Or, and Xor gates that you will notice is that their left side (the input side) can accept any number of wires. To see this in action, place one of these components in the facet. Then repeatedly select its left side and use the creation button to draw wires out of it. After three wires have been connected to the input side, the gate grows to accommodate more. Note that the vertical cursor location along the input side is used to select the position that will be used when a new wire is added.

To negate an input or output of a digital gate, you must negate the wire connected to that gate. Select a wire and use the Negated command from the Arc menu. With this facility, you can construct arbitrary gate configurations. |

One useful feature of schematics is the ability to create an iconic representation of a circuit for use in other schematics. To do this, use the Make Icon command from the View menu. It helps to have created exports for all circuit connections before iconifying, so that the icon can include these. The newly created icon facet has simple graphics in it, but can be modified arbitrarily. To use this icon in another schematic facet, place an instance of the schematic (with New Facet Instance command of the Edit menu) and observe that the icon appears.

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