In this article in our EAGLE series we want to create our first project and start drawing a schematic.
Expand the “Projects” branch of the tree view in the EAGLE Control Panel. Some sample projects are available there. The yellow icons represent simple directories, the red colored icons are so-called project folders.
Click onto the Projects entry with the right mouse button now. The context menu opens and shows the entry “New Project”. Type in a project name of your own and confirm with the Enter key.
Now EAGLE creates a new folder with the project”s name. It already contains a file named eagle.epf which will store all the settings you will make while working with the project. To the right of the project folder”s name you will notice a green marker that indicates the project as active. If you want to add a description for the project, right-click on the project folder entry and select Edit Description. Enter your descriptive text in the bottom part of the window. The part above shows a preview of it. If you want, you can use HTML tags to format the text. It is also possible to add links to images or web locations, as shown in the image. The supported HTML tags are described in the EAGLE help function (Help menu, General help, Search for: HTML).
The next step is to create a new schematic. Right-click onto the project entry in the tree-view and select New…/Schematic. The Schematic Editor window appears. Our first action will be to place a drawing frame, which can be found in Frames.lbr. Use the ADD icon in order to place components or frames in the schematic. The ADD icon can be found on the left side in the icon toolbar.
Click onto the icon and a window opens with all the available libraries. Scroll down the list and look for frames. Expand the frames entry and choose one of the frames. After OK the frame can be placed in the schematic. Fix it with a mouse click at the coordinates origin. Now go on and try adding further parts. Rcl.lbr, for example, contains resistors, capacitors and inductors. Try out the search function as well.
Drawing a schematic with EAGLE
The ADD command places components. At the bottom of the ADD dialog you will find the Search line. There you can enter the name of the part, for example: LM555. If you want to make the search more flexible use placeholders like * and ?. For example: *555*. This gives more results.
I would like to mention two important things you should keep in mind before you start:
1. The default grid setting in schematics is 0.1 inch!
Please keep this setting. All EAGLE schematic symbols in all libraries are based on this grid. Of course, you are allowed to set it to millimetre (2.54mm), but you should not change the grid size.
The grid size used for the schematics is independent of the grid size used for the layout. More details in our article on layout.
2. Click the DISPLAY icon and switch on layer 93, Pins. There you can see exactly where the pins of a symbol have to be connected with a net.
Located on the left hand side of the schematic editor there is the icon toolbar. Hovering over one of the icons with the mouse shows its name and functionality in the status bar. Simply explore the icons. If you are not sure what you can do with a certain command, look into the help function. Press F1 and there you are.
An interesting command is SMASH. It releases name and value text from the symbol in order to move it or change its layer or size.
For fine adjusting a text, press the Alt key while you are moving the text. Alt activates the alternative grid that can have any size which is set in the GRID dialog. This can also be used with other commands like LABEL that places the net name or a cross reference.
The final step in creating a schematic should be the Electrical Rule Check. The result of this check is presented in the Errors window. Click onto the error and warning messages and EAGLE shows you where to look in the drawing. Please read the messages carefully and decide what to do. In some cases you will recognize that the issue reported in the message is okay for you. So simply Approve it.
The next article will introduce the Design Link interface which offers access to more than 550.000 components.