If you’re getting into more advanced Arduino projects, you have probably started exploring boards beyond the basic Arduino Uno. The Pro Micro is an excellent option for someone looking for an advanced board.
Before we get into the hardware in detail, let’s clarify a couple of things. The name “Arduino” refers to an open-source development solution that includes both hardware (boards) and software (the Arduino IDE program for writing code). Despite offering open-source tools for people to use, modify, and model after, the Arduino name remains licensed to the company and we can only use it to describe officially licensed Arduino hardware.
In this sense, the Pro Micro, produced by SparkFun, is not technically an Arduino board. It’s instead an Arduino-compatible board, one we can program using the Arduino IDE. If you are loyal to the Arduino brand, they offer a slightly larger version not to be confused with Sparkfun's ProMicro called the Arduino Micro.
See related product
Arduino Micro (With Headers) | A000053
Arduino Corporation Embedded System Development Boards and Kits ViewWhat is the Pro Micro?
The Pro Micro is noteworthy for its human interface device (HID) capability. Because the ATmega32U4 chip that runs on the Pro Micro is equipped with a full-speed USB transceiver, it connects directly to your PC. As a result, you can program the Pro Micro to emulate nearly any other input device, including a keyboard, mouse, or joystick. Here are a few other key features:
- Can accept unregulated input voltages as high as 12V
- Contains 18 I/O pins you can use as either digital ins or outs
- Nine pins featuring ADCs for analog inputs
- Five pins with pulse-width modulation capability
- Several pins that allow for serial inputs
The board is available in two models: a 3.3V/8MHz version and 5V/16MHz version.
Sparkfun Pro Micro 5v or 3.3v: Important Usage Considerations
The Pro Micro version you choose (3.3V or 5V) determines the maximum allowable voltage on any given I/O pin for the board. That means that if you want to interface the Pro Micro with external devices that operate at 5V, you can’t use the 3.3V version of the board. Your chosen version will also come into play when you upload code, so be sure you have the right board for your project.
If you need more than 5V of power (the standard supplied by USB) or you’re planning to use the device in the field, away from a USB supply, you may want to connect an external power supply. You can use the “RAW” pin with input voltages between the 12V input maximum and 1V more than the operating voltage (between 6V-12V on the 5V board, for example). Voltages in that range will down-regulate to the appropriate input level. Otherwise, the VCC pin accepts clean, appropriately regulated (3.3V or 5V) power input.
