Arduino uno r3 board without logo

Product Highlights

UNO R3 is the latest easy-to-use open-source controller launched in 2012. In terms of hardware, compared with UNO, there aren’t big changes. The biggest difference lies in the USB-to-serial circuit part, where it uses an ATmega16U2 microcontroller. Because of cost reasons, there aren’t big changes in software compared with the previous version.

Functions:

1. Pin changes:

Two I²C pins (SDA and SCL) have been added next to the AREF pin (actually just copies of Analog 4 and 5, not extra I²C interfaces).

In addition, two more pins were added near RESET. One is IOREF, which allows expansion boards to adapt to the voltage on the board (for example, UNO uses 5V; in the future, it could be adjusted to 3.3V by changing the source). The other is a reserved pin for future use.

2. More stable RESET circuit:

The RESET button has been repositioned, moved closer to the USB interface corner of the board, making it easier to press.

3. ATmega16U2 replaces 8U2:

This doesn’t mean R3 can run faster or has more flash (still 16K), but it updates the USB interface service. In theory, UNO R3 can emulate USB HID devices such as MIDI / Joystick / Keyboard.