The board also has its own ceramic resonator to maintain its clock speed and time. A USB micro port is given to power it or communicate with the PC.
What is R in Arduino Uno R3
The R3 in Arduino Uno stands for revision 3. The Arduino Uno was first released in 2010, and the R3 revision was released in 2012. The R3 revision includes several changes, including:
- A new USB controller chip, ATmega16U2 provides more memory and faster communication speeds.
- Two new pins, IOREF and RESET.
- The I2C pins (A4 and A5) have been moved to the side of the board.
The IOREF pin is used to communicate the voltage of the Arduino board to the shields. This allows shields to be compatible with both the Arduino Uno, which operates at 5V, and the Arduino Due, which operates at 3.3V.
The RESET pin can reset Arduino. When this pin is pulled low, the microcontroller will reset and start executing the bootloader.
The other changes in the R3 revision are minor and do not affect the functionality of the Arduino Uno.
Technical Specification of Arduino Uno Rev3
Here are some additional details about the Arduino Uno R3:
- Dimensions: 68.6 x 53 x 18 mm
- Weight: 25 g
- Operating voltage: 5 V
- Input voltage: 7-12 V
- Digital I/O pins: 14 (of which 6 can be used as PWM outputs)
- Analog inputs: 6
- Clock speed: 16 MHz
- Flash memory: 32 KB
- SRAM: 2 KB
- EEPROM: 1 KB
- Programming language: C/C++
The Arduino Uno R3 is compatible with the Arduino IDE, which is a free software development environment. The IDE provides a graphical user interface for code execution.
Arduino Uno R4
By the time you are reading this article, there is a high chance the Arduino Uno R4 is out on the market. Yes, you heard it right the Arduino Uno R4 is about to launch with the power of an ESP32-S3 mini chip, hence allowing the Arduino board to now offer both Wi-Fi and Bluetooth capabilities.
The Arduino UNO R4 is the newest member of the popular UNO family. It features an upgraded Renesas RA4M1 32-bit Cortex-M4 processor, offering more processing power, memory, and features. Despite the improvements, the UNO R4 retains the same size, and compatibility with shields, and operates at a 5V voltage.
Arduino R4 will come in two versions:
- UNO R4 Wi-Fi
- UNO R4 Minima
Read more about the Arduino R4 here.
Conclusion
The R in Arduino Uno R3 stands for revision. Number three denotes that a total of three revisions are done to the Arduino Uno board. There are not many additional changes in the original Arduino Uno and R3 except the addition of header pins, a Reset button, and an extra Atmega16U2 chip for serial communication. Read more about the Arduino R3 in this article.
