PART 1 : Creating your own components
Many times we want to use a component (most likely an integrated circuit or CI) into our designs, but there is not a Eagle component available. Creating a new component is not easy, and because of this I will use a better approach, which is to copy a similar component to a new library, then modify the component to fit our requirements.
Let's continue breaking the process into steps.
Step 1: Create a library for your components - or chose an existing library to add your new components.
If you want to create a new library, got to "File -> New -> Library".
Step 2: find a component with same form factor as the component you need.
Lets use an example: I want to use this SRAM into my design: CY7C1041GN-10ZSXI, but there is not an Eagle part avaialable for this memory. My memory is a a TSOP-II 44 pins SRAM, then what I need to do is find out a similar component on Eagle libraries.
Eagle has got a memory-sram.lbr library with several sram components. I will select the component CY7C1059DV33 from there as my template, because it is a TSOP with 44 pins, exactly the same for my own component.
Step 3: Copy the component to your own library.
Open the library you created on step 1: "file -> Open -> Library"
Step 4: On the Library window, type this command in the command area:
In this example, memory-sram is the library name (without the extension)
CY7C1059DV33 is the component name to copy.
This command will copy the device CY7C1059DV33 in library memory-sram.lbr to our own library, so we can edit it without changing the original component.
PART 2: Editing our new component
This is the original component we will be changing:
And this is the final component we want:
To do these changes and create a new component, follow the next steps.
Step 1: Open the Library with the component you going to modify
Step 2: Edit the Device
In this picture, I had already renamed the device name. To edit other attributes, use the Edit option.
Step 3: Next we want the change the package details, that is, pins and form factor.
This is done using the Edit Symbol option.
Step 4: Edit the component, removing parts ou adding new.
For example, use the "move" tool to resize the component to a larger size to allow adding more pins.
Use the "copy" tool to duplicate the I/O pins - the original component had 8 I/O pins, but our new component need 16 I/O pins.
Step 5: Save the new component before you close this window, or the changes will be lost.
Note: In this specific example, it is not possible to remove pins A18 and A19. Read carefully the error message when you try, and you will understnad next optional step:
Step 6: What to do if Eagle did not allow you to remove pins.
If you could not remove the pins A18 and A19 on Step 5, this happened because those pins was are connected to the package signals.
To remove the unwanted pins, first disconnect them in the package.
In the Edit screen, click "connect"
In the Connect window, select the pins G$1.A16 and G$1.A17 on the right and click "Disconnect". Click OK and retry Step 4.
Ant this concludes this first part. Short but very useful to understand how to overcome a common issue with Eagle, which is finding the parts we need for our designs. Not sure when will improve this document. Maybe some day when I get bored with everything else.