![datasheet of arduino uno datasheet of arduino uno](https://i.stack.imgur.com/GDsC6.png)
See the chart below to see a detailed mapping of said pins. The Arduino Uno features 20 I/O pins, with the option for six of the digital outputs to function as PWM outputs and six variable pins.
![datasheet of arduino uno datasheet of arduino uno](https://docs.arduino.cc/static/2de2c8ff00fc05065634e3823a9266c4/A000067-pinout.png)
The board itself holds an 16 MHz clocking quartz crystal, an USB connector, a power jack, and an ISCP header. With 32 KB of Flash memory, 2 KB of SRAM, and 1 KB of EEPROM, this little processor can carry out most any task you can ask of it. Smaller than the palm of your hand (2.7” x 2.1”), the board is based around the removable Microchip ATmega328P microprocessor, which features 8-bit resolution and its own USB bootloader for reprogramming. The Arduino Uno is one of the most popular compact development boards on the market.