Learning the Mentor Graphics PADS Part-1

Learning the PADS User Interface

What you will learn:

Modeless Commands
Panning & Zooming
Object Selection Methods

Note: This tutorial will use PADS Layout to demonstrate the user interface. Unless otherwise noted, the techniques shown below also apply to PADS Logic.

1. Begin by opening a sample PCB Design.

1.1 Start PADS Layout.

Select Start > Programs > Mentor Graphics SDD > PADS2005 SP2 > PCB Layout > PADS Layout.

The PADS Layout welcome screen should appear.

1.2 Open a sample PCB Design.

Select File > Open. Browse to C:\PADS Projects\Samples and open preview.pcb.

You should see a PCB layout similar to the one below...

1.3 You can use this sample PCB file to test the user interface features described in this tutorial.

2. Modeless Command.

Modeless commands are simple shortcut keys that can be used to change settings or perform a given action at any time. To enter a modeless command, simply type the specified shortcut key(s) followed by any necessary parameters and press enter.

When you begin typing a modeless command, the Modeless Command window will appear. In addition to displaying the user's input, the Modeless Command window will also provide realtime help for the command currently being entered.

A few of the available modeless commands are listed below.

For a complete list, select Help > Modeless Commands.

*Shortcut key*	*Description*
UN <n>	Multiple undo command. <n> is the number of operations to undo
RE <n>	Multiple redo command. <n> is the number of operations to redo.
S <s>	Part search. <s> is the reference designator.
G <n>	Set the design grid spacing to <n>.
GD <n>	Set the display grid spacing to <n>
M	Display the shortcut menu for the current mode.

Note: In PADS Layout, the grid commands use the design units specified in

Tools > Options > Global > Design Units.

Although this setting will default to mils, the preview PCB file is set to inches.

As an example, try searching for the part labeled D2:
Enter the search shortcut key, s, followed by the part reference, d2.

This will bring component D2 into view and center the mouse pointer over it.

3. Panning & Zooming

There are several methods available to move about a design and adjust the magnification level.

3.1 Using Zoom Mode.

You can enter zoom mode by selecting

View > Zoom, pressing Ctrl + W, or by clicking the button on the toolbar.
While in zoom mode, the following features are available:

· Zoom in one level - Left Click.

· Zoom out one level - Right Click.

· Zoom in by a specific amount - Click and hold the left mouse button in the center of the area you wish to view and drag the mouse up. Release the left mouse button when the desired zoom level is shown.

· Zoom out by a specific amount - Click and hold the left mouse button in the center of the area you wish to view and drag the mouse down. Release the left mouse button when the desired zoom level is shown.

When you are finished zooming, you can exit zoom mode by pressing escape.

3.2 Panning

You can pan around the design by using any of the following methods:

· Scrollbars - You can use the scrollbars at the right edge and bottom of the design window to pan vertically and horizontally.

· Mouse Scroll Wheel - If your mouse is equipped with a scroll wheel, you can use it to pan vertically.

· Insert Key - To center the design view on the mouse pointer, press the insert key.

3.3 View Sheet / Board

To view the entire sheet (PADS Logic) or board (PADS Layout) press the Home key.

3.4 Middle Mouse Button

If your mouse has a scroll wheel or middle mouse button, the following features will be available:

· Center View - Click and release the middle mouse button to center the view on the mouse pointer.

· Zoom In - Click and hold the middle mouse button in the center of the area you wish to view and drag the mouse up. Release the middle mouse button when the desired zoom level is shown.

· Zoom Out - Click and hold the middle mouse button in the center of the area you wish to view and drag the mouse down. Release the middle mouse button when the desired zoom level is shown.

4. Object Selection Methods

4.1 Selection Filter

The selection filter will allow you to 'filter out' the object types that you are not interested in, making it easier to select specific components.
To access the selection filter,

select Edit > Filter... or press Ctrl+Alt+F.

The selection filter window for PADS Layout is shown below.

Checked objects are able to be selected, unchecked objects are filtered out. In PADS Layout it is also possible to filter out specific layers of the pcb by using the Layer tab.

As an example, open the selection filter and press the Nothing button. Then select the Vias check box and close the selection filter window. You will now only be able to select vias. If you press Ctrl+A, all of the vias will be selected. This could be useful if, for instance, you wanted to quickly change the size or type of all of the vias. Press escape or click in an empty area to unselect the vias.

4.2   Selection Filter Shortcuts

There is a faster method of changing the filter options. With nothing in the design view selected, right click to display the shortcut menu. The top portion of this menu consists of selection filter presets and is shown below.

Selecting a filter preset is the same as making the corresponding changes in the selection filter window. For example, selecting the Select Components preset is the same as only checking Parts and Glued Parts in the filter window.

Return the selection filter to it's default state by right clicking and selecting Select Anything from the top of the menu.

4.3   Selection Cycle (PADS Layout Only)

In crowded pcb designs it may become difficult to select a particular object, even with the use of the selection filter. To overcome this problem you can cycle through all the nearby objects by using the Tab key.

To demonstrate this feature, select the top left pin of part U3.