Digital I/O Pins:
• 54 digital pins
○ 15 pins support PWM output

Analog Input Pins:
• 16 analog inputs

DC Current per I/O Pin:
• 20 mA

DC Current for 3.3V Pin:
• 50 mA

Flash Memory:
• 256 KB (8 KB used by bootloader)

SRAM:
• 8 KB

EEPROM:
• 4 KB

Clock Speed:
• 16 MHz

Communication Interfaces:
• 4× UART (hardware serial ports)
• I2C
• SPI

USB Connection:
• Type-B

ICSP Header:
• Yes

RESET Button:
• Yes

Dimensions:
• 101.5 mm × 53.4 mm

Weight:
• 37 g