Introduction: Pro Micro Tips

About: Lazy Old Geek

This Lazy Old Geek (L.O.G.) likes Arduinos. My current favorite is the Pro Micro. I buy Pro Micro ‘clones’ from

Unlike the standard Arduino, they use an ATmega32U4 microcontroller instead of the ATmega328. One difference is that it has a USB Serial built in plus a separate serial port.

Sparkfun has some excellent documentation here:

Use this to setup your Arduino environment.

Here are some tips that might help you if you’re interested in them.

There are two versions, a 5V/16MHz and a 3.3V/8MHz.

TECHNOBABBLE: The reason why the 3.3V version uses an 8MHz clock is that the ATmega32U4 is not rated to run at 16MHz at 3.3V. They might or might not work.

TIP: When you plug the Pro Micro in, the PC may identify it as a Leonardo or Lilypad. This doesn’t matter.

When setting up your Arduino ‘Tools’ ‘Board’ I always scroll down to the section ‘Sparkfun AVR boards’ and select ‘Sparkfun Pro Micro’

BEWARE: I believe on my setup there’s another ‘Sparkfun Pro Micro’ under the heading ‘Sparkfun boards’ that does not work.

IMPORTANT: After selecting the board, select ‘Tools’ ‘Processor’ and select the one you bought. The reason why this is important is that I think I’ve selected the wrong one and ‘bricked’ a Pro Micro (which basically means Arduino couldn’t see it). But all is not lost, Sparkfun to the rescue.

Bricked Pro Micro: So if you do Brick a Pro Micro, try this:

As it says it’s a tricky process and every time I do it, it takes me several attempts but so far I’ve always recovered the board.

Hardware Tips:

On one Pro Micro, I was doing some testing then tried to pull out the USB micro cable and the whole connector came with it. Fortunately, I was able to solder it back on and got it to work. Some where I read that someone else had the same thing happened. So what I did is hot glue the USB connector to the PCB.

Also I have several Pro Micros both 5V and 3.3V. While you can tell which is which by the 8.0MHz (3.3V) or 16.0MHz (5V) crystal, my eyes aren’t that good so I took some nail polish, yellow for 3.3V and red for 5V and marked my PCBs.