Adding a footprint to a device

[Anonymous]

My design contains 6 trimpots. The best match I could find in my installed libraries was a SparkFun TRIMPOT which includes a footprint for a Bourns 3386U. I couldn't find those cheaply so I've ordered some 3362P's from the Far East, for which I found and imported a model.

But the schematic in the imported model has a much bigger zigzag for the resistor than all the other resistors in my schematic. (Perfectionist? OK, but if I am one I'm a fair weather perfectionist. And it's been sunny all day.)

So I want to take a copy of the 3362P footprint and add it to the SparkFun device. But having spent a good while trying, I can't see how to do that. (I could equally copy the SparkFun schematic symbol into the imported model. But I don't see how to do that either, and it doesn't seem quite like the right way to do it.)

Perhaps someone can enlighten me.

[rachaelATWH4]

Hello,

Open your target library which contains your main trimpot device. Now in the control panel navigate to the library with the new footprint. Expand the hierarchy of that to show the contents of the footprints sub folder and then right click on the one you want and choose “copy to library” from the context menu. Now go back to your library editor, open your trimpot device and add the new footprint as a package variant. I’d give more specific instructions but I’m on my phone now not my laptop so can’t look at EAGLE. Let me know if you have any issues. 

Best Regards,

Rachael

[Anonymous]

Hi Rachel -

Many thanks for your help once again - it's refreshing to find someone so willing to help (unlike some forums I could name where you get treated like an imbecile as a newcomer, even without properly reading the question).

I tried to follow your instructions and I now have the right footprint in the destination device, though I'm not sure I did it quite how you said. But now when I try and use the device it complains about unconnected pins. Presumably, not only do you have to add the footprint but also link the pads to the schematic - or maybe the new footprint names the pads differently to all the existing ones. I fear I may be getting the device definition in a mess and don't see a way of backtracking, e.g. removing the footprint I added.

I'm also getting very confused by the different windows that pop up, but too confused at the moment to ask a sensible question. I'll go and get some lunch then maybe see if the documentation helps. And your kind reply to my spice question will be for after tea!

Bet regards - Philip

[rachaelATWH4]

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@Anonymous wrote:

Many thanks for your help once again - it's refreshing to find someone so willing to help (unlike some forums I could name where you get treated like an imbecile as a newcomer, even without properly reading the question).

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You are very welcome 🙂 I enjoy helping people, it's my way of giving back to the community, and in some small way it may help make EAGLE more successful. Also I know what it's like to be a newbie and get badly treated when seeking help on forums. Fortunately the EAGLE community is generally a pretty friendly bunch for the most part 🙂

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@Anonymous wrote:

I tried to follow your instructions and I now have the right footprint in the destination device, though I'm not sure I did it quite how you said. But now when I try and use the device it complains about unconnected pins. Presumably, not only do you have to add the footprint but also link the pads to the schematic - or maybe the new footprint names the pads differently to all the existing ones. I fear I may be getting the device definition in a mess and don't see a way of backtracking, e.g. removing the footprint I added.

I'm also getting very confused by the different windows that pop up, but too confused at the moment to ask a sensible question. I'll go and get some lunch then maybe see if the documentation helps. And your kind reply to my spice question will be for after tea!

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Ok so it sounds like you are almost there. You will need to go map the pins to the pads and then it'll work. So, a few years ago I wrote a tutorial series on creating library parts over on element14. You can find it here:

EAGLE Tutorial Series

Part 3 talks about creating a device and deals with mapping pins to pads with the UI. Part 4 may also be interesting as it deals with package variants which is what you are doing here. Take a look and let me know if anything is unclear or you just need further explanation on anything 🙂

Best Regards,

Rachael

[Anonymous]

OK I got there in the end. I'm still confused by the various windows and the relation between them that open up. If you double-click a .lbr file in Control Panel you get a GUI representation of the XML in that file (yes, I even resorted to looking at the XML!) with columns for the device, footprint, 3D Package and Symbol. You can right-click and Edit any of those but when you've finished, you don't seem to be able to go straight back to the 4-column device view. Those edit windows seem to be the same as what you get if you right-click and Open in Library on a footprint or symbol in the expanded view of the .lbr file in Control Panel. So far so good (though I forget now how I found that Connect dialogue - no matter). But then I saw a button Open in Library Manager. So what is the Library? I thought we were already in it!

I'm sure it'll be worth it in the end, but I must say, soldering up my projects on stripboard like I've been doing for 50+ years never hurt my brain like this! Forgive my ramblings.

Best regards - Philip

[rachaelATWH4]

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@Anonymous wrote:

... but when you've finished, you don't seem to be able to go straight back to the 4-column device view.

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You need to click on the 'Table of Contents' icon to get back to the main window of the library editor with the four columns.

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@Anonymous wrote:

Those edit windows seem to be the same as what you get if you right-click and Open in Library on a footprint or symbol in the expanded view of the .lbr file in Control Panel. So far so good (though I forget now how I found that Connect dialogue - no matter). But then I saw a button Open in Library Manager. So what is the Library? I thought we were already in it!

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Yes those windows are the Device, Symbol and Footprint editors the same as you can access from right clicking and opening from other editors.

You get to the connect dialog from within the device editor, and then double clicking on the package entry from the list on the right hand side.

So you have seen the Library Editor, but the Library Manager is another entity. It's just a dialog box which is accessible by right clicking on the top level 'Libraries' folder in the Control Panel. In there you can look at what libraries are used in the currently loaded design, what libraries are set to "In Use" in EAGLE, and what libraries EAGLE can see which can be downloaded and/or set to in use. In here you can also purge your system of all the bundled libraries so you don't have to have them clogging up your libraries view.

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@Anonymous wrote:

I'm sure it'll be worth it in the end, but I must say, soldering up my projects on stripboard like I've been doing for 50+ years never hurt my brain like this! Forgive my ramblings.

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There is a lot to learn with any CAD package but you're doing well so far. It'll get easier with practice and will be well worth the effort in the long run 🙂

Best Regards,

Rachael