Eagle layout help

Ok, I’ve broken down and decided to use Eagle for a project so I could re-use the components that make up the power supply switching in a duemilanove, the FTDI circuit, and replacing the 328 with a 644 for the larger memory & snd serial port.
That part is done. Now I’m trying to add some new parts.

  1. I found the MAX321 chip (I have 12V source so I can get by with 2 less charge pump caps) but when I add it the power & ground pins (13 & 12) do not show up. How do I add them? Where can I find the surface mount package for this?

  2. There’s about a gazillion capacitors in the library. Any suggestions for 1uF surface mount caps for the MAX231?

  3. I have moved (on the schematic) the 2 resistors that go between the FTDI chip and the ATMega. I can’t for the life of me get the 2nd one to accept wire connections back on its pins. Is there some trick?
    Same for the capacitor that goes in ARef - I moved it, can’t get it reconnected.
    Same for the Reset line into the programming header.

  4. Is there a Female DB9 connector somewhere? I tried searching for 9, DB9, not finding anything.




You've messed up the grid and the components are off grid and don't connect. click and select one component that is not connecting, hold down ctrl and double click. This will place the object back on the grid and you can then connect your wires.

I'll type up some more answers after washing some dishes. Just a small token to my wife helping me with the car reversing obstacle sensor project yesterday. I posted it in exhibition.

Thanks Liudr, that solved several schematic creation issues. Any suggestions for finding parts? Or the missing power/gnd pins?

crossroads, if you use the invoke (above the text tool) tool, you can click on that part which brings up a dialog box with hidden pins (i have no clue why you would want to hide pins on a schematic... it makes no freakin sense)

Awesome, thanks Nick!

Yes, I can't see any reason to hide pins.

I bet the part that you're using have named the VCC and GND pins as "VCC" and "GND" gates. If you want to connect to them without "invoke", drop a 5V supply to the diagram, put it at the voltage regulator. Then try to name it "VCC" with naming tool or add a label "VCC" with the label tool. I don't quite know why but this seems to put all gates "VCC" in one node, including the 5V supply that you just named VCC. This way the parts will have air wires among themselves and to the 5V.

yeah, but what if you have different vcc voltages in the same schematic? or am i not understanding vcc…

I have 3 different voltage sources. +5V, Vin (which will be +12V), and 3.3V from the FTDI chip.
The MAX231 gets +5 &+12.
+5V was already in the schematic. The eagle symbol did call the hidden pins Vcc & Gnd.
I kinda like seeing what I’m getting - no hiding stuff, no making connections I don’t know about.

Got the connector figured out - needed to search for Sub-D. Found piezo noise makers also under buzzer.

Just wait until you cant find the part you want... then its time to break out the calipers and do some measuring ;)


Just want to share experience with you on smaller buzzers: there are two pin spacings I found, 6.5mm and 7.5mm. My Phi-1 shield goes with 6.5mm and if I try on a 7.5mm, it won’t fit! Had to bend pins and I don’t want to do bending. In my Phi-2 shield design I opened up the solder pad drill holes and hope both sizes will fit. Will check after dinner.

You could always put in several sets of mounting holes wires up in parallel Liudr, give yourself some options to use different parts. I've got another thread opened on driving them. Can you take a look and let me know what you're using? Thanks


I just started working with Eagle a few days ago and have run into a couple of the same problems as you. I want to thank the others for their tips. Very helpful to me.

I'm not clear on whether you are using new parts or recycled parts. What I found while drawing a schematic and ordering my parts via Mouser was to look at the specs for the part I'm using. For example I have some surface mount caps and resistors. The specs called out a package type of 1206 on one component. Sure enough I found a corresponding package size for that part in the Eagle libraries.

I also downloaded the 'Sparkfun' library for Eagle. It has every part used in Sparkfun products all nicely mapped out and ready to drop into a schematic/board.

As for finding parts in the other libraries. Oy. What a 'fun' thing.


Thanks Mr Swarf. What I did was to take a duemilanova layout, stretch the board out to maximum size that Eagle Light supports (100mm x 80mm) and go from there, adding the new components I wanted. I'll try your idea for the library, see if I can find a piezo buzzer I can get specs on.

I'm happy to help.

I just looked in the Sparkfun library and there are a lot of buzzers listed.

Also, if you right click on a part, like a resistor, select 'package' it will give you a nice menu of choices for package type/size etc.

Not all parts have choices tho. I used the MAX231, it only has 14pin DIL as a choice, I wanted to use the TSOP instead. Haven't looked into revising an existing part into a new package yet.

CrossRoads: You could always put in several sets of mounting holes wires up in parallel Liudr, give yourself some options to use different parts. I've got another thread opened on driving them. Can you take a look and let me know what you're using? Thanks

Sure, where is the thread?


This one Liudr.