Arduino Pro Mini 328 - 3.3V/8MHz (DEV-11114)

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  • Arduino Pro Mini 328 - 3.3V/8MHz - SparkFun DEV-11114
  • Arduino Pro Mini 328 - 3.3V/8MHz - SparkFun DEV-11114
  • Arduino Pro Mini 328 - 3.3V/8MHz - SparkFun DEV-11114


Arduino Pro Mini 328 - 3.3V/8MHz - SparkFun DEV-11114 perfect for Arduino projects!

It’s blue! It’s thin! It’s the Arduino Pro Mini! SparkFun’s minimal design approach to Arduino. This is a 3.3V Arduino running the 8MHz bootloader. Arduino Pro Mini does not come with connectors populated so that you can solder in any connector or wire with any orientation you need. We recommend that first time Arduino users start with the Uno R3. It’s a great board that will get you up and running quickly. The Arduino Pro series is meant for users that understand the limitations of system voltage (3.3V), lack of connectors, and USB off-board.
We really wanted to minimize the cost of an Arduino. In order to accomplish this, we used all SMD components, made it two layers, etc. This board connects directly to the FTDI Basic Breakout board and supports auto-reset. The Arduino Pro Mini also works with the FTDI cable but the FTDI cable does not bring out the DTR pin so the auto-reset feature will not work. There is a voltage regulator on board so it can accept voltage up to 12VDC. If you’re supplying unregulated power to the board, be sure to connect to the “RAW” pin on not VCC.
This is the latest and greatest version of this board breaks out the ADC6 and ADC7 pins as well as adds footprints for optional I2C pull-up resistors!


  • Length: 33mm (1.3")
  • Width: 18mm (0.7")


  • ATmega328 running at 8MHz with external resonator (0.5% tolerance)
  • Low-voltage board needs no interfacing circuitry to popular 3.3V devices and modules (GPS, accelerometers, sensors, etc)
  • 0.8mm Thin PCB
  • USB connection off board
  • Weighs less than 2 grams!
  • Supports auto-reset
  • 3.3V regulator
  • Max 150mA output
  • Over-current protected
  • DC input 3.3V up to 12V
  • Onboard Power and Status LEDs
  • Analog Pins: 8
  • Digital I/Os: 14


Arduino Pro Mini 328 - 3.3V/8MHz Schematic

Getting Started with the Arduino Pro Mini:

You'll need a few bits and pieces to get going. You'll definitely want some headers, a USB cable, and FTDI. The FTDI will be used to program (and power) the Pro Mini. The headers are actually optional, but they're the easiest way to interface other devices to the Pro Mini.

What's the difference between the Arduino Uno R3 and the Arduino Pro Mini?:

So what differentiates the Arduino Pro Mini from the Arduino Uno? Well, the most obvious difference is the form factor. The Pro Mini's pretty...well mini, measuring in at just 33 x 18mm. It's about one-sixth the size of the Arduino Uno. The compact size is great for projects where you may need to fit the Arduino into a tiny enclosure, but it also means that the Pro Mini is not physically compatible with Arduino shields although you could connect to shields using jumper wires!
Arduino Uno R3 Vs Arduino Pro Mini
The Pro Mini has almost as much processing power as the regular Arduino, but there are a few major hardware changes you should be aware of before you start adapting your project to the Pro Mini. The first major difference is that the voltage the Pro Mini operates at is 3.3V. Unlike the Arduino Uno, which has both a 5V and 3.3V regulator on board, the Mini only has one regulator. This means that if you've got peripherals that only work at 5V, you might have to do some level shifting before you hook it up to the Pro Mini (or you could go for the 5V variant of the Pro Mini).
Another major difference between the Pro Mini and the "standard" Arduino lies in the speed at which the ATmega328 runs. The Pro Mini 3.3V runs at 8MHz, which is half the speed of an Arduino Uno. We put a slower resonator on the Mini to guarantee the safe operation of the ATmega. That said, don't let the slower speed scare you away from using the Mini; 8MHz is still plenty fast, and the Pro Mini will still be capable of controlling almost any project that the Arduino Uno R3 can.
The last missing piece of hardware is the Atmega16U2-based USB-to-Serial converter and of course the USB connector too. This isn't a problem, as long as you have an FTDI Breakout Board to hook up when you want to upload code!

Pro Mini 3V3 Board and Pin Layout:

Pro Mini 3V3 Board and Pin Layout

Pro Mini 3V3 Pin Functions:

Arduino Pro Mini 328 pin functions


  • A portion of this sale is given back to Arduino LLC to help fund the continued development of new tools and new IDE features.
  • Replaces: DEV-09220
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3 Reviews

  • 4
    Title of review 723

    Posted by Roald Baud on 31st Mar 2014

    When you really need a tiny Arduino and keep a reasonable number of analog and digital pins, the Pro Mini is really great. Of course there's now the Pro Micro but I think the serial connections from the board to the computer through a FTDI adapter are eas

  • 5
    Title of review 722

    Posted by Ewan (Prot on 8th Oct 2013

    Thanks for letting us know, we have altered the price to match.

  • 5
    Title of review 721

    Posted by Matt on 26th Jun 2012

    Bought this to replace my dead Arduino Nano, absolutely perfect, very pleased with it

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