ATmega32 Development Board (Arduino Programming Compatible)

UNO R3
Spec:
Microchip: ATmega328P
Structure: AVR
Clock Speed: 16MHz
Flash Memory: 32KB of which 0.5 KB is used by bootloader
SRAM: 2KB
EEPROM: 1KB
Operating voltage: 5V
Input voltage: 7-12V (recommended)
Input voltage: 6-20V (limit)

Nano
Spec:
Microchip: ATmega328P
Operating voltage: 5V
Input voltage: 7-12V (recommended)
Input voltage: 6-20V (limit)
Digital I/O pins: 14 (6 optional PWM outputs)
Analog input pins: 8
DC per I/O pin: 40 mA
DC for 3.3 V pin: 50 mA
Flash memory: 32 KB, of which 0.5 KB is used by bootloader
SRAM: 2 KB
EEPROM: 1 KB

Micro
Spec:
Microcontroller: ATmega32U4
Operating Voltage: 5V
Input Voltage (recommended): 7-12V
Input Voltage (limit): 6-20V
Digital I/O Pins: 20
PWM Channels: 7
Analog Input Channels: 12
DC Current per I/O Pin: 20 mA
DC Current for 3.3V Pin: 50 mA
Flash Memory: 32 KB of which 4 KB used by bootloader
SRAM: 2.5 KB
EEPROM: 1 KB
Clock Speed: 16 MHz
LED_BUILTIN: 14