Arduino Uno R3 is a basic microcontroller board based on the Atmega328 microcontroller and also the most popular version of the series. It has 14 digital inputs / outputs (6 of which can serve as PWM outputs (eg for motor control)), 6 analog inputs, 16MHz crystal oscillator, has 32 kB of Flash memory and 2 kB of SRAM , USB programming connector and Rx and Tx PC connection, external power connector (if not powered by USB), ICSP connector and reset button.
To communicate with Arduino Uno Atmega16U2 is now used for this purpose, it does not use the FTDI chip for USB-to-Serial communication, unlike the previous boards.
Operating voltage: 5V
Power supply voltage (recommended): 7-12V
Maximum power supply voltage (not recommended): 20V
Digital I / O pins: 14 (6 of which provide PWM output)
Analog input pins: 6
I / O pins current (5V): 40mA
I / O pins current (3.3V): 50mA
Flash memory: 32KB (ATmega328) of which 0.5 KB is used for bootloader