By Warren Stephens,2014-05-28 14:27
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     Placing Components Using Unions and Radial Move Tutorial

     In this lesson you will use additional component placement features to complete the placement of the tutorial design. In this lesson: Placement with component unions Radial placement of components Automatic component nudging Restriction This tutorial requires the Cluster Placement, General Editing, and Radial Placement security options. In PADS Layout, click Installed Options on the Help menu to determine whether you can proceed. Preparation If it is not already running, start PADS Layout and open the file named previewnet.pcb in the \PADS Projects\Samples folder.

     Placement with component unions

     Using the Cluster Placement feature, you can merge components together as a "super component," or union, as it is called in PADS Layout. Once the components exist as a union they move together instead of individually. You can simplify component placement and reduce placement steps by creating component unions consisting of ICs and decoupling capacitors.

     Copyright ? Mentor Graphics Corporation 2005 All Rights Reserved. This document contains information that is trade secret and proprietary to Mentor Graphics Corporation or its licensors and is subject to license terms. No part of this document may be photocopied, reproduced, translated, distributed, disclosed or provided to third parties without the prior written consent of Mentor Graphics. Trademarks that appear in Mentor Graphics product publications that are not owned by Mentor Graphics are trademarks of their respective owners. Placing Components Using Unions and Radial Move Tutorial 1

     Dispersing Components

     Tools menu > Disperse Components

     To distribute the components around the board outline using Disperse: Click Yes to confirm the dispersion. Making the keepouts invisible

     Setup menu > Display colors

     To change the visibility of keepouts: In the Outlines column, clear the Keepouts check box, and click OK to accept the changes and close the Display Colors Setup dialog box. Setting the net colors

     View menu > Nets

     Assign a color to the net +5V, to make the decoupling capacitors more visible during placement and orientation. To set net colors: 1. In the Net List, select +5V. 2. Click Add to add +5V to the View List. 3. In the View List, select +5V. 4. Select the dark gray color in the palette to display all component pins and vias connected to +5V in dark

gray. Setting the net visibility

     View menu > Nets

     Temporarily make the plane nets invisible. This clears the design area and helps in determining the best location for components. To set net visibility: 1. In the View List, select Default and in the View Details area, clear the Traces Plus the Following Unroutes check box to make them invisible. 2. Click OK to apply the visibility settings. 3. Close the View Nets dialog box.

     Placing Components Using Unions and Radial Move Tutorial


     Positioning the union members To create unions, group ICs and capacitors for each of the IC part types. PADS Layout finds and creates similar unions automatically. To position components for the union: 1. Press Home to fit the view to the board outline. 2. On the standard toolbar, click the Design button. The Design toolbar appears. 3. On the Design toolbar, click the Move button. 4. Search for and select component U1 using the search and select modeless command by typing ssu1 and pressing Enter. 5. Place U1 inside the PCB outline. 6. Type ssc1 to select capacitor C1 and press Enter. 7. Press Ctrl+R twice while moving to rotate C1 180 degrees. 8. Right-click and click Flip Side (Ctrl+F) to mount C1 on the Secondary Component Side. 9. Position C1 under U1 with the +5V pin almost directly under the +5V pin of U1, as shown below, and click to place C1.

     Place other parts Create other component groups of ICs and capacitors. Repeat Steps 4 through 9 above with similar capacitor and IC placements for: U7 and C2 U4 and C3 U5 and C4 U6 and C5

     Placing Components Using Unions and Radial Move Tutorial


     Creating a union To create a union: 1. On the Design toolbar, click the Select button. 2. With nothing selected, right-click in the workspace and then click Select Components. 3. Select U1 and Ctrl+click C1 to add C1 to the selection. Tip: When creating the unions, it is important that the capacitor is the last selection before creating a union with an IC. If you do not select the IC first, the wrong origin is used when you place the component union. 4. With both components selected, right-click and click Create Union. 5. Type ic_cap1 as the union name and click OK to create the union. 6. Repeat steps 1 through 4 with the other capacitor and IC groups, using the union names: U7 and C2 with union name ic_cap2 U4 and C3 with union name ic_cap3 U5 and C4 with union name ic_cap4 U6 and C5 with union name ic_cap5 Create similar unions To create similar unions, use the Create Like Unions command. This command looks for components with the same part types as the members of a base union and automatically merges them into a new union. To create like unions: 1. With nothing selected, right-click,

    and click Select Unions/Components. 2. Select the U1/C1 (ic_cap1) union. 3. Right-click and click Create Like Unions. 4. Click Yes to confirm the creation of like unions. 5. Click Yes to confirm the dispersion of new unions. 6. Repeat steps 2 through 5 for the U4/C3 (ic_cap3) union. All other unions are unique and do not have like part types. 7. Press Ctrl+Alt+E to view the extents of the design area. Examine the two new unions of components at the top left of the workspace.

     Placing Components Using Unions and Radial Move Tutorial


     Radial placement of components

     The placement tools let you place components on a radial grid. Use the radial placement features to place the LEDs and resistors. Set the radial move grid The radial placement tools let you specify all of the parameters for the radial grid. To set the radial grid: 1. Type the modeless command gp and press Enter to display the radial grid. 2. On the Design toolbar, click the Radial Move button. 3. In the Polar Grid Origin area, type 3000 in the X box and type 1100 in the Y box. 4. In the Inner Radius box, type 700. 5. In the Delta Radius box, type 100. 6. Leave all other settings at their default values. 7. Click OK to close the Radial Move Setup dialog box. 8. The polar grid origin is now located at the center of the arc radius. Placing the LEDs and Resistors Once the radial grid is established, move the components using the radial move command. To place components on a radial grid: 1. Type ssd1 and press Enter to select and move D1. 2. Press Ctrl+R three times to rotate the component 270 degrees. 3. Place D1 on the inner radius of 700 at 45.000 degrees. See the Status Bar for the placement coordinates. 4. Type ssd2 and press Enter. Rotate D2 three times and place it at 315 degrees on the same radius. 5. Type ssr7 and press Enter. Rotate R7 once and place it at 15 degrees on the same radius. 6. Type ssr6 and press Enter. Rotate R6 three times and place it at 345 degrees on the same radius.

     Placing Components Using Unions and Radial Move Tutorial


     7. Turn off the radial grid by typing the modeless command gp and pressing Enter. 8. On the Design toolbar, click the Select button to exit the Radial Move command.

     Automatic component nudging

     Tools menu > Options > Design tab

     This placement feature lets you automatically shove or nudge adjacent components when components are placed too close to each other or if they overlap. To nudge components automatically: 1. In the Nudge area, click Automatic to enable automatic nudging. 2. Click OK to apply the changes and close the Preferences dialog box. 3. With nothing selected, right-click and click Select Unions/Components. 4. Select

    a union, right-click and click Move. The component will attach to the pointer for moving. 5. Move it into a position where it slightly overlaps another union. Watch the software nudge the other union out of the way. 6. Do not save a copy of the design. You completed the placing components using unions and radial move tutorial.

     Placing Components Using Unions and Radial Move Tutorial



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