Pro Micro & Fio V3 Hookup Guide

Contributors: jimblom
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Heads up! This is for the Pro Micro (ATmega32U4) 5V and 3.3V versions. If you are looking for information about hardware on the Qwiic Pro Micro with the USB-C connector, make sure to check out the newer Qwiic Pro Micro USB-C (ATmega32U4) Hookup Guide.

Welcome to the new frontier of Arduino-compatible boards, made possible by the ATmega32U4. No longer does your Arduino need to be harnessed by an FTDI Cable, or an ATmega8U2, or any chip who's sole purpose is acting as an intermediary between your Arduino and your computer.

Pro Micro

The SparkFun Pro Micro [ 3.3V/8MHz and 5V/16MHz ] is a really cool, little development board. It's an Arduino-compatible microcontroller, micro-sized, and it accomplishes with one single chip what old Arduino Unos, Duemilanoves, and Diecimeillas could never dream of: true USB functionality.

Pro Micro - 3.3V/8MHz

Pro Micro - 3.3V/8MHz

Pro Micro - 5V/16MHz

Pro Micro - 5V/16MHz



This tutorial also covers the Fio v3, which works a lot like the Pro Micro but adds features like easy XBee interfacing and LiPo charging.

Fio v3 - ATmega32U4

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Covered In This Tutorial

This tutorial aims to introduce you to both the hardware and firmware sides of the Pro Micro (and Fio v3). We'll also dedicate a few pages to helping install the boards on Windows and Mac. Here's a summary of what will be covered:

Suggested Reading

Before delving into this tutorial, here are some concepts you should be familiar with. If you're not, consider checking out the related tutorial first.

Serial Communication

Asynchronous serial communication concepts: packets, signal levels, baud rates, UARTs and more!

What is an Arduino?

What is this 'Arduino' thing anyway? This tutorials dives into what an Arduino is and along with Arduino projects and widgets.

Installing Arduino IDE

A step-by-step guide to installing and testing the Arduino software on Windows, Mac, and Linux.