Uno R3 — ATmega328P Development Board with USB-C
The classic entry-point into microcontroller development, now with a modern USB-C port. Built around the ATmega328P at 16 MHz with 14 digital I/O pins, 6 analog inputs, hardware UART/SPI/I²C, a barrel jack for standalone power, and the full Uno R3 shield-compatible pinout. Pre-soldered headers, ready to use. Fully compatible with the Arduino IDE — select Arduino Uno and upload.
- ATmega328P @ 16 MHz
- 14 Digital I/O (6 PWM)
- 6 Analog Inputs (A0–A5)
- Pre-soldered Headers
- 7–12V Barrel Jack
- USB Type-C
- Arduino IDE Compatible
- Uno R3 Shield Compatible
- 5V Logic
- ICSP Header
Full R3 shield pinout with SCL/SDA on the dedicated header. All Arduino Uno shields, community sketches, and libraries are compatible. The only difference from the original is USB-C instead of USB-B.
All I/O pins run at 5V. When connecting 3.3V sensors, ESP32 GPIO, or Raspberry Pi pins, use a logic level shifter to avoid damaging those components.
Electrical & Physical Specifications
Full specifications for the Uno R3 ATmega328P USB-C development board. All values at 5V supply unless stated.
- Microcontroller
- ATmega328P (8-bit AVR)
- USB Connector
- Type-C (data + power)
- Header State
- Pre-soldered, shield-ready
- Logic Voltage
- 5V DC
- USB Input Voltage
- 5V via USB-C
- External Power Input
- 7–12V DC via 2.1 × 5.5 mm barrel jack
- 5V Output
- Regulated 5V @ up to 500 mA (USB)
- 3.3V Output
- Regulated 3.3V @ up to 50 mA
- Digital I/O Pins
- 14 (pins D0–D13)
- PWM Pins
- 6 (D3, D5, D6, D9, D10, D11)
- Analog Input Pins
- 6 (A0–A5, 10-bit ADC)
- DC Current per I/O Pin
- 40 mA max
- Flash Memory
- 32 KB (0.5 KB used by bootloader)
- SRAM
- 2 KB
- EEPROM
- 1 KB
- Clock Speed
- 16 MHz crystal oscillator
- UART
- 1 × hardware serial (D0/D1)
- SPI
- 1 × (D10–D13 + ICSP header)
- I²C
- 1 × (A4 SDA / A5 SCL + dedicated header)
- Board Dimensions
- 53 × 68 mm
- Shield Compatibility
- Arduino Uno R3 standard footprint
- ICSP Header
- Yes (6-pin AVR ISP)
- IDE Compatibility
- Arduino IDE — select "Arduino Uno"
- Built-in LED
- D13 (user-programmable)
- Reset Button
- Yes
Pinout & Getting Started
The Uno R3 exposes its pins on two main headers plus dedicated I²C (SCL/SDA) and power rails. Standard Uno shield footprint — all community shields fit directly.
Digital I/O (D0–D13)
- D0 / D1 Hardware UART RX/TX
- D2 / D3 External interrupts INT0/INT1
- D3,5,6,9,10,11 PWM outputs (6 pins)
- D10–D13 SPI (SS/MOSI/MISO/SCK)
- D13 Built-in LED (LED_BUILTIN)
Analog Inputs (A0–A5)
- A0–A5 10-bit ADC (0–5V)
- A4 / A5 I²C SDA/SCL (shared)
- SCL / SDA Dedicated I²C header (R3)
- AREF External voltage reference
Power Pins
- VIN Barrel jack input (7–12V)
- 5V Regulated 5V out (USB or barrel)
- 3.3V Regulated 3.3V out (50 mA max)
- GND Multiple ground pins
- RESET Active-low reset
Communication
- Serial D0/D1 — USB via onboard chip
- I²C A4 SDA / A5 SCL
- SPI D10–D13 + ICSP header
- ICSP 6-pin AVR ISP header
-
1Connect via USB Type-C
Use a data-capable USB-C cable. The board powers up automatically and creates a serial COM port. The green power LED illuminates.
-
2Install driver if needed (Windows)
Most Windows 10/11 systems detect the USB-to-serial chip automatically. If the COM port doesn't appear, install the relevant USB serial driver for your board's chip.
-
3Select board in Arduino IDE
Go to
Tools > Board > Arduino AVR Boards > Arduino Uno. Then select the COM port that appeared under Tools > Port. -
4Upload Blink to verify
Open
File > Examples > 01.Basics > Blinkand click Upload. The D13 LED should blink once per second — your board is working. -
5Power standalone with barrel jack
For projects away from a computer, connect a 7–12V DC centre-positive supply to the barrel jack (2.1 × 5.5 mm). The onboard regulator provides 5V and 3.3V.
Applications & Use Cases
The Uno R3 is the most widely used development board in the world — a well-documented platform with thousands of community tutorials, compatible shields, and libraries covering almost every use case.
The standard first board for electronics and programming education. Unbreakable community support, official Arduino tutorials, and classroom-proven curriculum.
Read temperature, humidity, pressure, distance, light, and motion sensors. Log data over serial or store to SD card modules.
Drive DC motors, stepper motors, and servos via compatible shields or driver modules. PWM outputs handle precise speed and angle control.
Control OLED displays, LCD shields, 7-segment modules, NeoPixel strips, and LED matrices with well-supported libraries.
Drop any Uno R3-compatible shield directly onto the board — motor shields, relay shields, Ethernet, GSM, data logging, and more.
Control relays, solenoids, and actuators. Communicate with other microcontrollers via UART, I²C, or SPI for larger system builds.
Choose the Uno when shield compatibility, the larger form factor, or the extra 3.3V current capacity matter. Choose the Nano when breadboard use or a compact embedded footprint is more important. Both use the same ATmega328P and IDE settings.
Frequently Asked Questions
- Yes. This board uses the full Arduino Uno R3 pinout including the dedicated SCL/SDA header. All Uno-compatible shields, motor shields, relay shields, display shields, and community add-ons plug in directly.
- Yes. Connect a 7–12V DC centre-positive supply via the barrel jack (2.1 × 5.5 mm). The board selects the power source automatically. For motors or high-current shields, a powered barrel supply is recommended over USB.
- Go to Tools > Board > Arduino AVR Boards > Arduino Uno. Then select your COM port under Tools > Port. No special processor settings needed — just upload directly.
- All digital and analog I/O pins operate at 5V logic. When connecting 3.3V devices such as an ESP32, Raspberry Pi GPIO, or most modern sensors, use a logic level shifter to avoid damaging the 3.3V device.
- Up to ~500 mA when powered by USB. With a capable barrel jack supply, the limit is higher but still constrained by the onboard regulator's thermal rating. Each individual I/O pin is limited to 40 mA. Use driver modules for motors and high-current loads.
- This is a third-party board compatible with the Arduino Uno R3. It is not manufactured by Arduino S.r.l. but uses the same ATmega328P, the same R3 pinout, and is fully compatible with the Arduino IDE and the entire Uno ecosystem.