Arduino Leonardo Schematic


I want to use the layout of the Arduino Leonardo for my project. I’ve downloaded the .zip file and opened it with EAGLE, but there’s something in the schematic I do not understand:

What do R2 and R3 do? And why is their value NM? Whats the difference between AGND, UGND and GND?

Thanks for your help!


NM = not mounted? Check the pictures, see if they are installed.
Lets you keep the Analog Ground seperated from the USB Gnd for quieter analog operation.
All grounds should end up connected at one place, see iif you can follow them on the .brd file.

So can I remove and replace them with simple wires?

R2 & R3? Yes.

Thank you!

But when I connect AGND, UGND and GND with each other, the part L2 is useless, isn't it?

I forgot the screenshot from the schematic

Yes. Have you seen my little '32U4 design?
Scroll down about halfway

Or this one

Ah ok, that means I can simplify my curcuit.
So am I correct that I only need 2 22Ohm resistors and the 500mA fuse for the USB connection?

If so, I would take another look on my curcuit tomorrow and remove some unnecesseray parts.
It would be very nice if you could take a look at it then.


And another thing: If I connected the VBUS with +5V, the atmega32u4 would also run (an be programmable) without an external power supply, right?

I found another strange value for the inductivity L2: MH2029-300Y
What does that mean? Which L should I buy?

What does that mean? Which L should I buy?

What do you mean? You have a part number, buy that part.

But I thought you were connecting the GNDs and didn't need the inductor.