Evaluating Component Placement

Before the placement position of components is determined, the Floor Planner is used to evaluate whether all components can be placed or whether to group components and roughly place them while taking relations among groups into consideration. In other words, it is a tool for efficient trial and error testing before starting detailed designing. In this lesson, the following components are placed outside of the board outline.

1. Click from the CAD File Manager.

The “Placement Grid”, predefined in the design rule library, is displayed as the grid.

1. Click (Placement/Wiring) from the CAD File Manager.

z Starting the Floor Planner

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Note

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To use the Placement/Wiring Tool…

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The layout of the Editor for the Floor Planner is as shown below.

1. Menu bar

The commands for the Floor Planner are displayed on this menu bar. 3. Viewer

This controls display on the canvas. In addition, two selector buttons, DRC (a) and COM (b), are provided.

a. Online DRC ON/OFF button

b. ON/OFF button for communication with schematic 5. Edit-mode indicators

These indicators are used to specify:

a. Placement grid, b. Coordinates, c. Component search side, d. ON/OFF of display grid, e. ON/OFF of input grid,

f. Visible layer,

g. ON/OFF of unconnected net, h. ON/OFF of group net display 12. Estimated wiring length

This field displays the total estimated wiring length for an unconnected net or an increase or decrease in the estimated wiring length if this length has been changed because of command operation.

[2. Tool bar], [Panel Menu], [6. Canvas], [7. Message area], [8. Dialog], [9. Assist menu], [10. Origin mark], and [11. Scale] are the same as those for the PC Board Shape Edit Tool.

Refer to “Editor for the PC Board Shape Edit Tool” on page 3-2.

a b

d

g he f c

Reference

z Editor for the Floor Planner

4. Panel menu 3. Viewer 8. Dialog box 6. Canvas 9. Assist menu 1. Menu bar 10. Origin mark 2. Tool bar

7. Message area 5. Edit-mode indicators 12. Estimated wiring length

11. Scale

a b

Because the components to be used are already defined on the net list (NDF) and design rule list (RUF), the necessary components are prepared on the PC board database when the Board Generation Tool has been executed.

However, because these components have been internally prepared and their placement position has not been determined, they are not displayed on the canvas. Components in this status are called “unplaced components".

Now, let’s take a look at the list of unplaced components. 1. Click (Query Data) on the tool bar.

2. Select Unplaced Component in PCB Data from the panel menu.

The Query window is displayed, showing the list of unplaced components.

3. Close the Query window.

Click Close.

z Querying Unplaced Components

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The layout area input by the PC Board Shape Edit Tool and the area occupied by all the components can be checked before executing placement.

1. Select Utilities Æ Placement Design Info. from the menu bar.

The Placement Design Info is a tool that calculates occupancy ratio based on

information on the layout and component areas. By checking the calculated values, you can evaluate whether all components can be placed before actually executing placement.

If the component occupancy ratio is close to 100%, placement/wiring may be impossible. It is therefore necessary to re-input the layout area or evaluate the component shapes.

2. After checking, close the Placement Design Info dialog box.

Select File Æ Quit from the menu bar for the Placement

z Checking the Component Occupancy Area

Menu bar Utilities Æ

Placement Design Info.

Component Occupancy Area = Total component area (input when footprint is registered) Component Occupancy Ratio = Component Occupancy Area

÷ Available Area Size Available area Keep-out area size

(placement keep-out area) Area size (layout area)

Note Lesson

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Place components temporarily on the canvas without worrying about the clearance. In this way, rough layout of the components can be grasped and placement can be easily executed later.

In the lesson, arrange all the unplaced components in a vacant area other than the layout area.

1. Use the Viewer to display the canvas as shown below so that areas other than the layout area can be seen.

(Zoom) (Zoom In) (Zoom Out)

To use the Viewer, refer to “* Using Viewer” on page 3-15.

2. Select (Stack Components) from the tool bar. 3. Select Unplaced from the panel menu.

As soon as Unplaced has been clicked, placement is started and all the unplaced components will be placed outside of the board outline.

4. Click (Show Full Data) in the display action area to display all the data.

z Arranging Components

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Reference

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* Display Area Storage Function

“View operation” of the Viewer is explained on page 3-15. The Viewer also has a function to hold up to three display areas.

Screen buffer

Displays the area displayed immediately before on the canvas. Stores the current display area to the screen buffer.

Next we will actually use the display area storage function.

1. Change canvas display. (Zoom)

(Zoom In) (Zoom Out)

2. Click STORE for the Viewer.

3. Click 1 for the screen buffer.

4. Change the canvas display. (Zoom)

(Zoom In) (Zoom Out)

5. Click 1 for the screen buffer.

The area stored by clicking STORE

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Display the component reference designators.

This reference designator is displayed only in the Board Designer and is not the data for actual symbol marks or other components.

1. Select View Æ Ref-Des from the menu bar.

z Displaying Reference Designators

Menu bar View Æ Ref-Des Caution ！ Lesson Click

The reference designator is displayed in white at the center of each component.

* Floor Plan

The Floor Planner has many functions for efficient trial and error testing before starting detailed designing.

In addition to the functions explained in this section, the tool also has the following functions:

Designing by group area

Components closely related to each other can be grouped and a group area can be placed, taking the relation among groups (net among groups) into consideration.

Trial Placement

The components are automatically placed one by one, while checking their connection with the key component, so that the wiring length can be shortened.

Save Placement Result

Several placement results can be saved so that the best placement can be determined by comparing these results.

In this way, the Floor Planner helps you in calculating designing.

The Floor Planner only checks for overlapping among component areas. It does not execute detailed checking, such as checking “clearance between pins” that is predefined by the design rule. For accurate placement, use the Placement/Wiring Tool.

Caution ！