First of all, I'm new on this forum, so I hope to have chosen the right section. Maybe I should've lurked some more... Sorry about that. I'm working on making a derivative of the Leonardo board, but I've never worked with microcontroller chips directly and I'm afraid to end up having to remake the …

Welcome to the forum. My thoughts: I recommend connecting all of the VCC's to your supply voltage and not leave any disconnected, and use decoupling caps near the processor for each supply pin. I recommend connecting all the grounds to ground. 43 is connected to ground on Leonardo. The Eagle file…

The connections inside the processor chip are necessarily very thin. They provide multiple ground points to avoid a voltage drop from one side of the chip to another, were there to be only one external ground. You defeat this concept if you don't ground all of the ground pins. So yes, connect them …

Thanks for clarifying that, Nick. dmjlambert: The Eagle file is difficult to follow, and I don't know the exact logic they used for calling the traces leading to ground R2 and R3, but you can actually see the traces leading to ground on my Leo. There is some discussion of that here: resistor valu…

Dig_Gil: "ESD Protectors". If they are zeners, I didn't know that. It's weird they aren't represented accordingly with zener symbols on the schematic. My mistake, sorry about that. That is interesting. I was confused and need to retract/refine my statement. There are in the place you would norma…

Dig_Gil: You mean the "RN3B" and "RN3C" on the Leonardo's schematic? Those under "NOT USED"? No I mean R2 and R3 on the schematic, which are actually just traces on the board. They are not resistors and they are marked NM on the schematic and they appear to be traces which connect the grounds to…

dmjlambert: No I mean R2 and R3 on the schematic, which are actually just traces on the board. They are not resistors and they are marked NM on the schematic and they appear to be traces which connect the grounds together. Gotcha.

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How to use the pins on ATmega32U4

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