First of all, Arduino Uno R3 Chinese Clone is a microcontroller board utilizing the ATmega328P same like the Italian version. It has 14 digital input/output pins (of which 6 pins function as PWM outputs), in addition, 6 analog inputs, also 16 MHz quartz crystal, in addition to a USB connection, also, a power jack, an ICSP header, in addition to a reset button. It also contains everything to support the microcontroller. Just connect it to a computer with a USB cable or power it with an AC-to-DC adapter or battery to get started. Furthermore, you can use your Arduino Uno R3 Chinese Clone without worrying too much about doing something wrong. Worst case scenario you can replace the chip for almost a few dollars and start over again.

Each of the Arduino Uno 14 digital pins on the Uno may serve as an input or output. Using pinMode(), digitalWrite(), and also, digitalRead() functions. They operate at 5 volts. Consequently, each pin is capable of providing or receiving 20 mA as recommended operating condition. Furthermore, each pin has an internal pull-up resistor (disconnected by default) a 20-50k ohm. The current provided by any I/O pin should not exceed 40 mAmps. If the current exceeds 40 mAmps this would probably damage the microcontroller permanently.

Also, some pins have specialized functions:

• Serial: 0 (RX) and 1 (TX). Used to receive (RX) and transmit (TX) TTL serial data. These pins are connected to the corresponding pins of the ATmega8U2 USB-to-TTL Serial chip.
• External Interrupts: 2 and 3. Using these pins you can trigger an interrupt on a low value, a rising or falling edge, in addition to the change in value. See the attachInterrupt() function for details.
• PWM: 3, 5, 6, 9, 10, and 11. Provide 8-bit PWM output with the analogWrite() function.
• SPI: 10 (SS), 11 (MOSI), 12 (MISO), 13 (SCK). Furthermore, these pins support SPI communication using the SPI library.
• LED: 13. drives the onboard LED. While the pin is HIGH value, the LED turns ON, hence when the pin is LOW the LED turns OFF.
• TWI: A4 or SDA pin and A5 or SCL pin, support TWI communication using the Wire library.

Also, the Arduino Uno has 6 analog inputs, labeled A0 through A5, each of which provides 10 bits of resolution (i.e. 1024 different values). By default, they measure from 0 to 5 volts. Furthermore, you can increase the upper-end range using the AREF pin in addition to the analogReference() function.

There are a couple of other pins on the board:

• AREF. The Reference voltage for the analog inputs. In conjunction with analogReference().
• Reset. Bring this line LOW to reset the microcontroller. Yet the reset button on shields usually blocks the one on the board.