Arduino Pro Mini

Arduino Pro Mini

The Arduino Pro Mini is a small board with all surface mount parts. It has all of the I/O of the Arduino Uno, plus the addition of two more analog inputs. There are a couple of models of this card, one 5V/16MHz, and one 3.3V/8MHz.

This is one of our favorite boards. There is nothing on it that doesn't contribute to the basic functionality of the ATmega328. We could buy a knock-off Arduino Uno for a little less, but in fact it has too much on it! If we are doing basic R&D, we would use the Uno. It allows us to use shields, which provide modules we may need. When the R&D is done, out come the Arduino Pro Minis for the actual finished project.

The pins on the Arduino Pro Mini and the Arduino Pro Micro are about the same, upto the SPI port on 11, 12, and 13. At that point, the Pro Micro changes to 14, 15, and 16. The PWM pins on the Pro Mini are identified by circles around the pin, just like the Pro Micro.

It must be someone else's favorite, too, because it is one of the most copied boards out there. Not every copy is an exact copy, though, even the originals! For an example, see the image below:

A few of the many variations of the Arduino Pro Mini.
Figure 1.
A few Arduino Pro Minis.

As you can see from the image, there are four different boards, with different pinouts, all calling themselves Arduino Pro Mini. The ones that actually are Pro Minis are identified by the Sparkfun logo to the left of the ATmega328. Yet even they are different. The one in the lower left has A0-A7, while the one in the lower right has only A0 through A5. The one in the upper left has A0-A7 and an SPI port. The one in the upper right has A0-A7, but A6 & A7 are on the end of the board. For the only "real" pinouts, see the Arduino Pro Mini Pinouts page.

Another example, which matches one of the boards in the image above, is from the Sparkfun Protosnap, which includes other devices besides just the Arduino Pro Mini.

A size comparison of the four small form factor Arduino boards is helpful to see where the Arduino Micro fits in the tiny Arduino board lineup.

Arduino Pro Mini
MCU ATmega328
DigitalPins 14
Analog Inputs 8
Analog Outputs 0
Operating Voltage 5 / 3.3
Operating Frequency 16MHz
3.3V Output None
Test Current Draw5v=17mA 3.3V=2.5mA
Web Site SparkFun Electronics
  1. Information from manufacturers and other sources.
  2. Test current from sketch that exercises I2C, SPI, and analog pins.
Arduino Pro Mini pinout.
Figure 3.
Arduino Pro Mini Pinout

The pinout of the Arduino Mini is generally shown with A4 through A7 on the analog side, but genuine variations exist which only have A4 and A5 located there, while A6 and A7 are missing.

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