What microcontroller is used in the Arduino Uno board?

• A. B ATmega2560
• B. A ATmega328p
• C. C ATmega32114
• D. D AT91SAM3x8E

Answer: (B)

The brain of the Arduino Uno is the ATmega328P microcontroller. This 8-bit AVR chip serves as the main processor, executing your sketches, handling I/O, timers, and memory management. It provides enough flash space for program storage, a small amount of RAM for variables, and a little EEPROM for non-volatile data, all running at a 16 MHz clock to keep things responsive for typical Arduino projects. The UNO also includes a separate USB-to-serial converter to enable programming over USB, but the ATmega328P is the processor actually running your code.

Other boards use different processors: the Arduino Mega uses the ATmega2560, which is a larger-capacity MCU for more I/O and memory; the Arduino Due uses an ARM-based AT91SAM3X8E; and there isn’t a standard MCU called ATmega32114 associated with the UNO.