Microcontroller Boards
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• the UNO R3 is legacy hardware. Production for the UN R3 has ceased as of June 2016. This page serves as reference material. The most recent UNO is the UNO R4.

The OSEPP™ Uno R3 Plus board is the basic starter model. It serves as a great starting point to the wonderful world of Arduino. This board uses the 8-bit, AVR, RISC-based ATmega328P microcontroller from Atmel.


New in R3:

  • Added SCL/SDA pins next to AREF header
  • Added IOREF pin to power header


“Plus” Features:

  • Replaced USB-B connector with more popular mini-USB connector
  • Added Molex connector for easy connect to OSEPP™ sensors and other I2C devices.


Microcontroller ATmega328P
Clock Speed 16 MHz
Flash Memory 32 KB
Operating Voltage 5V
Input Voltage 6-12 V
Digital I/O Pin Count 14 (including 6 for PWM output)
Analog Input Pin Count 6
Other Connections Mini-USB
ICSP for ATmega328p
DC power connector
4-pin latchable I2C connector
Dimensions 2.95 x 2.13 x 0.61 inches (75.0 x 54.0 x 15.5 mm)
Power Source USB or external DC power supply



  • 8-bit AVR RISC-based microcontroller running at 16 MHz
  • Connects to a computer via a standard USB cable
  • Flexible power source (USB or DC power)
  • ICSP header for programming microcontroller
  • Compatible with existing Arduino software libraries
  • Compatible with the Ethernet and Motor Controller Shields


The ATmega328P comes with the Arduino bootloader preloaded. There is an ICSP (In-Circuit Serial Programming) header for the ATmega328 to optionally replace the bootloader.

As an added precaution, the board comes with a resettable polyfuse on the USB connection path. To prevent damage to the USB port, the fuse will trip when the current to the port exceeds 500 mA.

The input and/or output pins are brought out to the headers, providing a convenient way to prototype projects without the need of soldering or desoldering.



Stock Code Product Name
UNO-03 OSEPP™ Uno R3 Plus



OSEPP™ Uno Schematic (PDF)
OSEPP Uno EAGLE Files OSEPP zip files


This board is based off of the Arduino Uno designed by Arduino, and is released under the
Creative Commons Attribution Share-Alike License. The original design can be found at


Learning Center:

What You Need

Uploading Your First Sketch

  1. Get the Arduino software if you have not already
    1. Download from http://arduino.cc/en/Main/Software
    2. Unzip the zip file to somewhere like C:\ (on Windows), so you will end up with a folder like C:\arduino-1.0.1
  2. Prepare for serial communication
    1. Connect the mini USB end of the cable into the board
    2. Connect the other end of the cable into a USB port on your PC/Mac
    3. If your computer prompts for drivers, point it to the “drivers\FTDI USB Drivers” subfolder of the Arduino software, e.g. “C:\arduino-1.0.1\drivers\FTDI USB Drivers”
    4. You should now see the LED labeled ON near the reset button light up
  3. Load the sketch
    1. Open the Arduino software
    2. Open the LED blink sketch: File menu > Examples > Basics > Blink 

Screen Shot 2016-05-11 at 1.07.09 PM

                3. Select the Arduino Uno.  

Screen Shot 2016-05-11 at 1.08.05 PM

                4. Select the serial port: Tools > Serial Port

Screen Shot 2016-05-11 at 1.09.45 PM

This is the serial port for the board’s built-in FTDI. If you do not know which one this is, you can find out by going into Device Manager > Ports (COM & LPT), and look for a “USB Serial Port (COMx)”

                5. Upload the sketch: File > Upload to I/O Board
                6. Wait for the “Done uploading” message in the bottom blue status bar

4. The LED labeled L near pin 13 should now blink on and off every second.


5.     Congratulations! You have successfully uploaded your first sketch to your board.


Alternative Install Guides

Windows : http://arduino.cc/en/guide/windows

Mac : http://arduino.cc/en/guide/macOSX

Linux : http://playground.arduino.cc/Learning/Linux

Also the main Arduino page has troubleshooting guides for the basic errors encountered : http://arduino.cc/en/guide/troubleshooting