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www.elektor.com Elektor International Media

Whether you are an electronics enthusiast or engineering professional, this book provides the reader with an introduction to the use of the CadSoft’s EAGLE PCB design software package.

EAGLE is a user-friendly, powerful and affordable software package for the efficient design of printed circuit boards. It offers the same power and functionality to all users, at a smaller cost than its competitors. A free version of EAGLE is available to enthusiasts for their own use.

EAGLE can be used on the main computing platforms including: Microsoft Windows (XP, Vista or Windows 7); Linux (based on kernel 2.6 or above) and Apple Mac OS X (Version 10.6 or higher). Any hardware that supports these software platforms will run the EAGLE application.

The book is intended for anyone who wants an introduction to the capabilities of EAGLE. The reader may be a novice at PCB design or a professional wanting to learn about EAGLE, with the intention of migrating from another CAD package.

This book will quickly allow you to: obtain an overview of the main modules of EAGLE: the schematic editor; layout editor and autorouter in one

single interface; learn to use some of the basic commands in the schematic and layout editor modules of EAGLE; apply your knowledge of EAGLE commands to a small project; learn more about some of the advanced concepts of EAGLE and its capabilities; understand how EAGLE relates to the stages of PCB manufacture; create a complete project, from design through to PCB fabrication. The project discussed in the book is a

popular, proven design from the engineering team at Elektor.

After reading this book while practicing some of the examples, and completing the projects, the reader should feel confident about taking on more challenging endeavors.

For the more sophisticated user … a more comprehensive guide and reference to EAGLE will follow from Elektor Publishing. Stay alert and keep watching for this!

Courtesy of CadSoft Computer GmbH (www.cadsoft.de), this book is supplied with a copy of Eagle on CD-ROM for MS Windows, Linux and Mac.

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GETTING STARTED GUIDE

LEARNING TO FLY WITH EAGLEGETTING STARTED GUIDE

Mitchell Duncan

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LEARNING TO FLY WITH EAGLE

Eagle CD-ROM included

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Table of Contents

Acknowledgments 11

Part 1 - Learning to Use EAGLE 13

Chapter 1 - An Introduction to EAGLE Software 15

Introduction 15

Conventions Used in this Guide 15

Mouse Clicks 16

Selection of Menu Items 16

Use of keys 16

What is EAGLE and what does it produce? 17

Chapter 2 - Eagle Installation & Startup 21

Windows 21

Linux 23

Mac OS X 23

Starting EAGLE 24

Projects 26

Libraries 27

Chapter 3 - Using the EAGLE User Interface 29

EAGLE Icons and Command Toolbars 30

Schematic Editor Toolbars 30

The PCB Layout Editor Action Toolbars 32

Command Toolbars 32

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The EAGLE Module Menus 34

The EAGLE Module Sub-menus 34

Schematic Editor Sub-menus 35

The File Sub-Menu 35

The Edit Sub-Menu 36

The Draw Sub-Menu 37

The View Sub-Menu 38

PCB Layout Editor Sub-menus 39

The File Sub-Menu 39

The Edit Sub-Menu 40

The Draw Sub-Menu 41

The View Sub-Menu 42

Navigating & Controlling EAGLE 42

Input Alternatives within EAGLE 42

Function Keys 42

Eagle Commands 44

Pan, Zoom & Screen Functions 45

Chapter 4 - Creating Your First EAGLE Project 49

Setting Up: Layers, Grids and Units 54

Layers: the DISPLAY Command 54

Grids and Units 55

Creating a Schematic Drawing using basic EAGLE Commands 57

Manipulating Objects within a Schematic 57

The USE Command & Libraries 57

The ADD Command 58

Adding a Frame 58

Adding components from a Library 59

Working with Objects: the COPY, MOVE, and MIRROR Commands 64

The DELETE Command 65

The UNDO and REDO Commands 65

Connecting Components Together 66

The NET Command 66

The JUNCTION Command 68

The SHOW Command 69

Completing the Schematic Drawing 70

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Creating a PCB Layout from a Schematic Drawing 72

Setting up the Printed Circuit Board Dimensions 74

Placing components on the Printed Circuit Board 75

Inserting the tracks : the ROUTE Command 76

Using the Autorouter 77

Automatic Forward &Back Annotation 79

Getting Output from EAGLE 81

Output to a Printer 81

Generating Image Files 84

Using the CAM module - generating output for PCB Manufacturing 85

Generating the output files for PCB Manufacturing 86

Chapter 5 - More Advanced Concepts & Commands in EAGLE. 89

General Commands 89

The INFO Command 89

The NAME Command 90

The Value Command 91

The Attribute Command 92

The Change Command 92

The Smash Command 96

The GROUP Command 97

Schematic Editor Commands 100

The Gateswap Command 100

The Pinswap Command 100

The Bus Command 101

The Label Command 106

The Invoke Command 107

PCB Layout Editor Commands & Concepts 109

Working with Devices 109

ROTATE Command 109

LOCK Command 110

Board Layers 111

The CIRCLE Command 112

The RECT Command 113

Polygons 116

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Manual Routing 121

The Via Command 121

The WIRE Command 122

The RIPUP Command 124

The SPLIT Command 125

The ROUTE Command 126

The HOLE Command 129

The DIMENSION command 130

Restricted Areas 131

Electrical Rule Check (ERC) 132

Design Rule Check (DRC) 133

Example - Design Rule Errors 134

Mistakes to Avoid - Fatal Design Rule Errors 136

Libraries 141

The Library Editor 142

EDIT an Object 144

Chapter 6 - An Introduction to PCB Manufacturing 147

Types of Printed Circuit Boards 147

Single-sided Printed Circuit Board 147

Double-sided Printed Circuit Board 148

Multi-Layer Printed Circuit Board 149

Fabrication of PCBs 151

Drilling Holes 152

Via and Hole Plating 154

Making Tracks: Photolithography & Etching or Milling 154

Photolithography & Etching 154

Laser direct imaging 158

Milling 158

Electroplating 159

Etching 159

Solder Mask Screening 162

Silk Screening 162

Hot Air Levelling 163

Routing and Trimming 163

Gerber Files 170

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Part 2 - Using EAGLE in a Real Project 173

Chapter 7 - A Full EAGLE Project ; Creating a Radiation Meter Counter 175

Drawing the Project Schematic 175

USEing the Libraries 179

ADDing the components 180

Drawing the NETS 184

Drawing the Project PCB Layout 185

Drawing the DIMENSIONS and adding Holes 187

Placing the Components on the PCB 191

Laying out the Copper 192

Restricted Areas 192

Routing the Signal Tracks 192

Ground Planes and Polygons 193

Final Design Rule Check 194

‘Pouring’ the Ground Planes 195

Fabricating your PCBs 197

Creating the PCB Manufacturing Files 197

Finding a PCB Fabricator 197

Appendix 1 - System Requirements and Features of EAGLE Package Variants 203

Professional Edition 203

General Features 203

Schematic Editor 204

Layout Editor 205

Autorouter Module 205

Standard Edition 206

Freemium Edition 206

Light Edition 206

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‘Author’s Note:

At the time of going to press, the most recent release version of EAGLE was V6.4. Although this book was written for V6.0, the instructions contained herein will be accurate for the most recent version of EAGLE.’

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Chapter 4 - Creating Your First EAGLE Project

You are now in a position to start creating your first EAGLE project. We’ll initially use the examples supplied with EAGLE.

After you have mastered this section, you may wish to be more ambitious and work through the project in Part 2 of this book; Creating a Radiation Meter Project, where you will be guided through all of the stages in creating a complete design. This project was published in the November 2011 edition of Elektor magazine; titled ‘Improved Radiation Meter’.

We’ll start by creating a new project and the schematic drawing.

In this tutorial we will learn how to add all of the components in this drawing and connect them together. Figure 4-2 is the Schematic Drawing for this tutorial. You can use this as a template from which to draw your own schematic.

Let’s begin by starting EAGLE and expanding down to the tutorial entry in the tree view by performing the following actions:

Projects, then ,

examples, next,

tutorial

Lastly, on tutorial and you will see a similar structure to the left pane (as in Figure 4-1).

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Figure 4-1. Starting a new Project


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Figure 4-2. Complete Schematic Drawing for Tutorial

If you now on New Project , a new project will be created and will be displayed in the tutorial files directory tree, as shown in Figure 4-3.

Creating Your First EAGLE Project

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Figure 4-3. Naming the New Project

Name your new project ‘My Project’ (or your preferred title) by typing in the name in the input

line and then .

This creates a sub-directory under tutorial, named My Project, containing all the files associated with your project. The last used projects and user-specific settings are also stored here, in Windows, as eaglerc.usr (~/.eaglerc for Linux and Mac)

You now need to define the path for the destination of your project directories. Type

Options > Directories

The following dialog box will appear as illustrated in Figure 4-4.


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Figure 4-4. Setting up EAGLE directories

You can now type in your desired location. For example, add the following to the end of the Projects field (preceded by a semicolon):

‘D:\My EAGLE Projects’.in the Projects field.

Now, open a new Schematic by:

My Project > New > Schematic

You will be presented with a new schematic window as in the Figure 4-5:

Figure 4-5. New Schematic Layout Window

Creating Your First EAGLE Project

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Setting Up: Layers, Grids and Units

Layers: the DISPLAY Command

To enable the Eagle Editor modules to perform their task properly, objects within drawings need to be grouped in different and separate layers, according to their purpose. These layers can also be selected, displayed and printed as a group. In general, the default settings will suit the new user of EAGLE.

To action the DISPLAY command you simply EAGLE will present the layer dialog box (see Figure 4-6), which will allow you to select and de-select layers for use. Layers will be discussed later in more detail, in Chapter 5.

Figure 4-6. Display Command dialog box


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Grids and Units

Objects cannot be randomly placed on a drawing, that is, at least not on a PCB layout. So, EAGLE provides a grid basis for placing objects.

Grid size or spacing can be specified by using the menu selection: View > Grid. The Grid dialog box then appears, as in Figure 4-7.

Figure 4-7. Grid dialog box

You are able to select from the alternative grid units of inches, millimeters, mils (1/1000ths inch) and mic (microns or mm). When set, this value applies to all values in the drawing.In the dialog box one can select:

i. the grid Size (i.e. the pitch between points on the grid) and unit (the base measurement me-thod),

ii. the display Multiple or the periodicity at which grid lines are displayed,

iii. an Alternative grid pitch which may be accessed by using the key.

Using this dialog , you can also choose whether to display the grid or not, and its style as dots or a solid line.

Grids and Units

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The default settings are given in the Figure 4-7 above. You may wish to change them to, say, 0.1inch spacing (since a large number of components are based on a 0.1inch manufactured specifications) with the Alternative grid pitch set to 0.025 inch. This will allow you to adjust some items to a finer positioning.

Your settings will be reflected in the grid and co-ordinates display, located towards the upper left-hand corner of the window, just above the corner of the workspace itself (see Figure 4-8). The numbers in this display comprise the selected grid size, followed by the position of the cursor, using the selected grid unit size.

Figure 4-8. Grid Units and Cursor Co-ordinates Display

The cursor position co-ordinates are given with reference to a datum point. This point is placed, by default, in a new drawing, near the bottom left-hand corner of the workspace. This is illustrated in Figure 4-9.

Figure 4-9. Cursor position Datum indicator


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The use of grids is much more important later in the book, when we begin exploring the use of the PCB Layout Editor, since all components must be precisely positioned in order to manufacture a PCB.

You may wish to use the following Table 4-1 to convert between the different bases of measurement

Table 4-1. Conversion between Millmetres, Inches & Mils

Millimeters (mm) Inches (inches) Mils (mils)

1mm 0.03937 inch 39.37mils

25.4mm 1 inch 1000 mils

0.0254mm 0.001 inch 1 mil

Of course, if you are using a very small scale, use can also use microns, where:1 micron = 1 x 10-6 meters =1 x 10-3 millimeters (1/1000th millimeter)= 0.03937 mils

Creating a Schematic Drawing using basic EAGLE Commands

Manipulating Objects within a Schematic

The USE Command & LibrariesThere are many libraries of commonly used components supplied with the EAGLE software.

So, in order to begin creating a schematic, we first have to gain access to the component information stored in the appropriate libraries. We do this by means of the USE command.

The USE command tells EAGLE which libraries to make available for searching and from which to source component data.

In your open schematic drawing, select a library to use by the following means:

Libary > Use, or by

The USE Command & Libraries

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This will open a dialog box, allowing you to select the frames.lbr library. You can select the library

by typing the name directly into the file name text area or, scrolling to and 2x , on the library name. (Alternatively you could simply execute the USE command by typing ‘USE frames.lbr’ into the command line). For our first tutorial, you should now repeat the same technique as above, and USE the following component libraries: rcl.lbr, diode.lbr, microchip.lbr, linear.lbr, pinhead.lbr, supply1.lbr and special.lbr. We’ll select the needed components from these libraries shortly.

The ADD CommandTo include objects in a drawing, from a library, we use the ADD command.

Adding a Frame

At this point we’ll use the ADD command to insert a frame into the drawing. (We’ll discuss this

command in detail later). To do this simply in the command toolbar on the left side of the window. A panel will appear (see Figure 4-10 ) and you should expand the frames entry

(by frames) and selecting the A4 landscape format frame (scroll down and DINA4_L ).Then press OK.

Figure 4-10. Add frame dialog

EAGLE will then snap back to your schematic window, with a red outline of the frame attached

to the cursor. Place the cursor at the desired bottom, left hand corner of your drawing and .


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This will place a frame in to your schematic window. Then move and at the top of the window.

(It would be preferable to place the bottom left hand corner of your frame at the drawing datum point as indicated in Figure 4-9. This will ensure the cursor co-ordinates correspond to positions within the frame.)

Your window should now look like that in the Figure 4-11.

Figure 4-11. New Schematic Editor Window with Frame

Adding components from a Library

We can now proceed to add components or devices to our schematic. Again, in the command toolbar on the left-hand side of the window. The dialog box, as in Figure 4-12, will appear showing the libraries available for use.


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Figure 4-12. Add device / select library dialog box

We are now going to add the components that comprise the project, and are listed in Table 4-2, to the schematic. As you can see these components are in different libraries, so we’ll have to add them from those libraries.

Table 4-2. Components List of Tutorial Project

Part Value Device Package Library

C1 30p C-EUC1206 C1206 rcl

C2 30p C-EUC1206 C1206 rcl

C3 10n C-EU025-025X050 C025-025X050 rcl

C4 47u/25V CPOL-EUTAP5-45 TAP5-45 rcl

C5 47u CPOL-EUTAP5-45 TAP5-45 rcl

D1 1N4148DO35-7 1N4148DO35-7 DO35-7 diode

IC1 PIC16F84AP PIC16F84AP DIL18 microchip 1

IC2 78L05Z 78L05Z TO92 linear

JP1 PROG PINHD-1X4 1X04 pinhead

JP2 APPL PINHD-1X17 1X17 pinhead

Q1 XTAL/S QS special

R1 2,2k R-EU_R1206 R1206 rcl

+5V +5V supply1

GND GND supply1


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We’ll start by adding the first component; a capacitor, labeled C1.

Now,̀ rcl. This will open the library rcl.lbr directory tree within the dialog box (as in the

Figure 4-13). Expand the section C-EU by .

You’ll now see, by scrolling down, the capacitor named C-EUC1026, together with descriptive

information in the right-hand panes of this dialog. Select it by on the correct component.

Figure 4-13. Add device dialog box

Now . EAGLE will skip back to the schematic window with the symbol for the capacitor highlighted in red, and connected & floating with your moving cursor. As you move your cursor you will see the coordinates in the upper left-hand of the window change. These give the cursor position, and therefore your component placement relative to the drawing datum.

Place your cursor, and the component in the desired location and simply (to end the ADD command).

The capacitor has now been added to the drawing.

An alternate method of adding a component is from the EAGLE Control Panel. If you have a schematic drawing open you can use this technique.


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Expand the libraries tree by Libraries . Scroll down, using the middle scroll bar until you

see the rcl.lbr library. Expand it with .rcl.lbr. Now select the device C-EU by on it. You will see a symbol diagram, a package diagram and some descriptions appear in the right-hand pane of the window as shown in Figure 4-14.

Figure 4-14. Component Description and Package in the Library

Move your cursor over to the right-hand pane and the first Device in the list (for example). The word ADD should appear, underlined, to the right of the Device name (as in Figure 4-15).

Now, scroll down in the right-hand pane until you see ‘EUC1206’, then on ADD (see Figure 4-15 ). Now move your mouse to to the schematic drawing with that device ‘attached’

to the cursor, ready for placement. Place the device with .


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Figure 4-15. Selecting a Device to add to a schematic

However, you may change the orientation of the component before placing it by repeatedly .

The component will rotate through 90° with each click.

You should now proceed to place all of the components from Table 4-2 into the drawing. After completing this, your drawing should look something like Figure 4-16.

Figure 4-16. Tutorial Schematic with only components


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Working with Objects: the COPY, MOVE, and MIRROR CommandsYou can manipulate objects in your drawing by using a set of commands designed for that purpose. These are the the COPY, MOVE, ROTATE and MIRROR commands. They perform as their names suggest.Using these commands you can correct any positioning of components. When using a command

and you need to select a component, you should on the ‘+’ approximately in the centre of the component. This point is used to indicate the center of the device for manipulation.

To terminate a command at any time use .

The COPY command allows you to replicate objects already in a drawing. Simply and

then on the object you wish to copy. To place the new device, on the point in the drawing where you would like the copied object to be placed.

The MOVE command simply allows you to move an object to another point. You just

then on the object you wish to move. Then, move the cursor to the desired position and to place the object.

ROTATE allows you to rotate a device by and then repeatedly on the device.

With each the device rotates though 90°, anticlockwise.

The MIRROR command essentially ‘flips’ a device on its vertical axis, producing a mirror image of itself. All connections remain intact. The MIRROR command could be used when placing components on the ‘underside’ of a PCB, but when viewed from the top. To action the MIRROR

command and then on the device you wish to ‘flip’. This command is mainly used in the PCB layout Editor.


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The DELETE CommandThe DELETE command is used to delete objects from a drawing or PCB layout.

If you’ve made some mistakes in the previous section while adding components to your drawing; don’t worry, they can be removed quite easily with the DELETE command.You can use the DELETE command on most objects in a drawing including; components, wires,

nets and buses. Simply and then on the object or component to be deleted. It will then be removed from the drawing.

When using the DELETE command on nets, wires or buses, it deletes one segment at a time.

To delete the whole construct, press the while deleting the object. With the DELETE command you can also delete groups of objects (more about this later). Similar principles apply to the use of the DELETE command in the PCB Layout Editor. You can delete any and all objects including; component devices, wires, pads, vias and text.

The UNDO and REDO CommandsThe UNDO and REDO commands are the EAGLE user’s best friends.

They are executed using these icons: . for UNDO and to run the REDO command. EAGLE keeps an unlimited undo function. This allow you to either immediately correct a inadvertent mistake, or “backtrack” through a long series of actions to a prior configuration. The REDO command allows you to reverse an action performed by the UNDO command.

A very convenient facility within EAGLE is the UNDO LIST. You start the facility by

Edit > Undo/Redo list...A dialog box will then open similar that in Figure 4-17, displaying a list of actions that can be selectively done/undone. You should experiment with this function to become familiar with it.

The UNDO and REDO Commands

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Figure 4-17. Undo List

The reader should note that all of the above commands can be used in the same way within

the PCB Layout Editor.

Connecting Components Together

The NET CommandThe NET command is used to “draw” ‘signal’ connections between points e.g. between a pin on a semiconductor component and a connector pin. A ‘pin’ has a specific meaning in EAGLE, and defines a net connection point. A net defines the relationship between interconnected points on the same functional ‘signal’ or ‘electrical’ net(work). However, the net may not resemble the final, physical layout of any subsequent, wiring in the finished PCB.

To show the pins in a schematic, use the DISPLAY command, and . The familiar dialog

box will appear, as described above. Now 93 Pins and then . The drawing’s components’ pins should now be highlighted with a green circle. An enlarged section of the drawing illustrates this, in Figure 4-18.


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Figure 4-18. Schematic with components & pins

Start the NET command by . A small cross-hair cursor will appear in the schematic window.

You can now begin connecting the pins on each component, by using the NET command, to

complete the schematic. on the first pin of the connection you wish to make, then navigate towards the terminating pin. The process looks like the Figure 4-19.

Figure 4-19. Drawing with the NET command

The NET Command

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After starting the NET command, you will also see a new toolbar appear in the main toolbar area, across the top of the schematic. It looks like Figure 4-20.

Figure 4-20. The NET parameter toolbar

This toolbar allows you to change attributes before and while drawing the net. For the moment we’ll leave the default settings as they are. The left-most part of this toolbar has a series of angled and curved lines on it. These are known as ‘bend modes’. While using a NET command (i.e. the cross-

hair cursor is visible), you can change the bend mode of the net line by repeatedly . You will see the style indicator change across the toolbar.

End the NET command by on the terminating pin. Try experimenting with this command, as it will be helpful when we deal with another command later in the PCB layout editor. If you make a mistake in connecting a net you can always remove it with the DELETE command.

The JUNCTION CommandIf you connect one net line onto another , EAGLE generates a connection betweenthe two nets. This can be set to occur automatically or be turned off by:

Options > Set > Misc and selecting the Auto set junction option.

If the option is de-selected (set to manual) then you can create a junction between nets by using the

JUNCTION Command. To do this: and a cross-hair cursor will appear in the drawing, associated with a light green dot. You can see this in action in Figure 4-21.


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Figure 4-21. Using the JUNCTION command

Move the dot onto the intersection of nets you wish to join, and a dialog box with a warning will appear, similar to that in Figure 4-22.

Figure 4-22. NET merge warning dialog

This displays the net segment you wish to merge with an existing net. If this is what you want, then

respond by . This will place a connecting node at the junction selected.

The SHOW CommandThe SHOW command is used to display names and other details of objects. It can be used on nets, signals, devices and components.

By way of example, to show the net ‘GND’, simply : and then move the cursor to the

connection point of IC1 pin 5 (VSS) and . EAGLE will highlight the net wires and each pin connected by this net, as well as the pin name of each part to which it is connected. Also, the status bar (at the very bottom of the drawing window) will display ‘Net: GND, Class :1 power’. These are the details of this net.

The NET Command

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The SHOW command remains active until terminated, which you can do by or .

You can also SHOW an object by activating the SHOW command and typing the name of the object

in the command line, then . EAGLE searches for, and highlights, the object when it is found. If EAGLE fails to find the object, a window appears with a ‘-‘ in the Sheet column of the display.

You can also select additional objects without the need to reactivate the SHOW command. You can

cumulatively select objects by + on each object to be highlighted. ( again on a highlighted object to remove the highlight).

Completing the Schematic DrawingYou should now, with a combination of the above commands and techniques, be able to complete the schematic drawing, as illustrated in Figure 4-23.

Figure 4-23. Tutorial Schematic Complete

There is one final step to finalizing the schematic, and to make sure is can be used to prepare a printed circuit board layout; the Electrical Rule Check (ERC).

The Electrical Rule Check (ERC) is used to test schematic drawings to ensure they are free from electrical errors, and to indicate possible sources of error before fabrication. This should be performed on every schematic drawing before finalizing it for other work. The ERC does not


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diagnose errors - unfortunately that is up to you !

To invoke the ERC command . The check will find 4 warnings in our demonstration file as in Figure 4-24.

Figure 4-24. Electrical Rule Check Warnings and Errors

These are: POWER Pin IC1 VDD connected to +5V

POWER Pin IC1 VSS connected to GND

Part F1 has no value

Part Q1 has no value

The messages inform you that:

i. the power pins are connected to signals other than expected. The power pins were named VSS or VDD in the library but are connected to GND and +5V. In the tutorial this has been done on purpose;

ii. components F1 and Q1 have no assigned values. This is not critical, since F1 is the Frame around the drawing, and Q1 is the crystal. We can assign its value at a later time, if necessary. It will not prevent us laying out a PCB, since we know its package type.

If you now on the first entry, EAGLE will show you, by using a line and box, the location of the reason for the problem in the schematic. We can remove them by

each one in turn. However, this is not advised as a working technique, since warnings should be avoided or resolved.

The NET Command

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If you haven’t been able to complete the demo drawing yourself, you may just simply keep it by

File > Save as. A dialog box will open and you can save your tutorial at this point with

whatever name you choose and . You can open it at any time to practice your EAGLE user interface skills.

Creating a PCB Layout from a Schematic Drawing

You may create a PCB (Printed Circuit Board) layout starting from either a schematic drawing or using only the PCB Layout Editor. We’ll continue our tutorial by choosing the option of using a schematic drawing as the starting point. In doing so we’ll use the EAGLE PCB Layout editor after, deriving all required information from the schematic.

If you haven’t already got the demonstration schematic file (demo1.sch) open, you should open it

now by using File > Open, and then navigating to the file under projects > examples > tutorial. You’ll see the, now familiar, diagram as in Figure 4-25.

Figure 4-25. demo1 schematic drawing


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