Datasheet

30/10/2019 https://store.arduino.cc/datasheet/index/index/url_key/arduino-uno-rev3-smd/
https://store.arduino.cc/datasheet/index/index/url_key/arduino-uno-rev3-smd/ 2/5
Input Voltage (limit) 6-20V
Digital I/O Pins 14 (of which 6 provide PWM output)
PWM Digital I/O Pins 6
Analog Input Pins 6
DC Current per I/O Pin 20 mA
DC Current for 3.3V Pin 50 mA
Flash Memory 32 KB (ATmega328P) of which 0.5 KB used by bootloader
SRAM 2 KB (ATmega328P)
EEPROM 1 KB (ATmega328P)
Clock Speed 16 MHz
LED_BUILTIN 13
Length 68.6 mm
Width 53.4 mm
Weight
25 g
Documentation
OSH: Schematics
Arduino Uno is open-source hardware! You can build your own board using the follwing files:
EAGLE FILES IN .ZIP SCHEMATICS IN .PDF
Programming
The Arduino Uno can be programmed with the (Arduino Software (IDE)). Select "Arduino/Genuino Uno from the Tools > Board menu (according to the
microcontroller on your board). For details, see the reference and tutorials.
The ATmega328 on the Arduino Uno comes preprogrammed with a bootloader that allows you to upload new code to it without the use of an external hardware
programmer. It communicates using the original STK500 protocol (reference, C header files).
You can also bypass the bootloader and program the microcontroller through the ICSP (In-Circuit Serial Programming) header using Arduino ISP or similar;
see these instructions for details.
The ATmega16U2 (or 8U2 in the rev1 and rev2 boards) firmware source code is available in the Arduino repository. The ATmega16U2/8U2 is loaded with a DFU
bootloader, which can be activated by:
On Rev1 boards: connecting the solder jumper on the back of the board (near the map of Italy) and then rese ing the 8U2.
On Rev2 or later boards: there is a resistor that pulling the 8U2/16U2 HWB line to ground, making it easier to put into DFU mode.
You can then use Atmel's FLIP software (Windows) or the DFU programmer (Mac OS X and Linux) to load a new firmware. Or you can use the ISP header with an
external programmer (overwriting the DFU bootloader). See this user-contributed tutorial for more information.