Building a New Symbol

PADS I/O Designer incorporates an advanced built-in symbol editor which can be used to create and edit PCB-level symbols or functional-level block symbols.

To create a new symbol in PADS I/O Designer:

Do one of the following:

Select Symbol > New.

Click the button on the Zoom Toolbar.

Enter a name for the symbol in the Symbol name: field.

To create a PCB Symbol, check the PCB symbol option. To create a functional block symbol, uncheck this option.

If this option is checked, the list of all existing functional blocks in the Functional block: field is activated.

For PCB symbols, select the functional block to which the new PCB symbol will belong, in the Functional block: field.

Select a background for the symbol from the list of those available in the Symbol background: field.

Click OK.

The new symbol is displayed in the Symbol Window.

Add ports to the symbol by dragging and dropping signals and pins from the Signals List and Pins List to the symbol in the Symbol Window.

You can create several ports by selecting a group of ports / signals and dragging the group to the symbol. Ports created by dragging signals have their binding type set to Signal. Ports created by dragging pins have their binding type set to Pin.

Note
	If you drag a bus to a PCB symbol, bus members are added as separate ports, since in most cases you do not want buses on PCB symbols. To override this feature, drag a bus to a PCB symbol with the CTRL key down. Then it will be added as one bus port.

Port Types and Shapes

PADS I/O Designer provides support for several port types. By default, port types are visualized by means of different port shapes. If you prefer straight lines without any decorations for ports of all types, uncheck the View > Symbol > Show Port Type option. Figure 9-5 shows the result of switching port types on and off.

Figure 9-5. Displaying Port Types

Further customization of the appearance of ports is possible. All available port types are listed under Setup > Settings + Port Types (under Symbol Editor) together with shapes assigned to them. There are several shapes to choose from. For available port types, see "Port Types".

Drawing Tools

Use the drawing tools to add Arcs, Circles, Lines, Rectangles or text to a symbol. The following sections describe all operations specific to these modes.

Arcs

To draw an arc, use the button on the toolbar. Then click the position where the arc should begin, and drag to its desired end.

Additional features available while drawing an arc are:

Orientation of the arc may be toggled with the Tab key.

Its middle point may be anchored with the Space key.

If the arcs middle point is anchored, it may be unanchored with the Backspace key.

Circles

To draw a circle, use the button on the toolbar. Then click on the position where one of the corners of circles bounding rectangle should lie, and drag to the opposite corner.

Additional features available during circle drawing are:

Hold down SHIFT while drawing to force an ellipse instead of an arbitrary circle.

Lines

To draw a line or polyline, use the button on the toolbar. Then click the position where the line should begin, and drag to its desired end.

Additional features available during line drawing are:

Press the Spacebar while drawing to add a new segment to the line. Added segments may be removed with the Backspace key.

Press CTRL while editing (dragging one of the handles) to add a new segment.

Press SHIFT while dragging the middle handle to split the line into two parts.

Rectangles

To draw a rectangle, use the button on the toolbar. Then click the position where one of the corners of rectangle should lie, and drag to the opposite corner.

Additional features available during rectangle drawing are:

Hold down SHIFT while drawing to force a square instead of an arbitrary rectangle.

Text

To add text to a symbol, use the button on the toolbar, then click the position where the text should begin and start typing. The text cursor (caret) is displayed, and normal editing operations, limited to a single line, may be performed. Editing is completed after the Enter key has been pressed. The Esc key may be used to cancel editing without adding the text to the symbol.

Snap to Grid

While drawing and editing symbols, Snap to Grid is enabled/disabled under Setup > Settings + Symbol Editor. If the Snap to Grid option is selected, all drawing operations obey this setting. However, snapping to grid may be temporarily disabled with the ALT key. For instance, to start drawing a line outside grid, it is not necessary to disable snapping to grid, but it is enough to hold the ALT key down while drawing.