The [Arduino Uno](https://www.ampheo.com/product/a000046-25542493) (based on the [ATmega328P](https://www.ampheo.com/search/ATmega328P) [microcontroller](https://www.ampheo.com/c/microcontrollers)) has the following pin configuration for digital and analog I/O:

**Digital Pins:**
Total: 14 pins (labeled D0 to D13).

* 6 pins can be used as PWM outputs (marked with ~): D3, D5, D6, D9, D10, D11.
* 2 pins support hardware interrupts: D2 (INT0) and D3 (INT1).
* Serial communication: D0 (RX) and D1 (TX) for UART.

**Analog Pins:**
Total: 6 pins (labeled A0 to A5).

* These can read analog voltages (0–5V) via the 10-bit ADC (1024 values).
* Can also be used as digital I/O (if needed, addressed as D14 to D19).

**Other Pins:**
**Power Pins:**

5V, 3.3V, GND, VIN (input voltage).

**Special Pins:**

* AREF (Analog Reference voltage input).
* Reset (D0) – Can be used to reset the MCU.

**Summary Table**

**Example Uses**
**1. Digital:**

* Read buttons/[switches](https://www.onzuu.com/category/switches) (digitalRead()).
* Control LEDs/[relays](https://www.onzuu.com/category/relays) (digitalWrite()).

**2. Analog:**

Read [sensors](https://www.ampheoelec.de/c/sensors) (potentiometers, LDRs) (analogRead()).

**3. PWM:**

Dim LEDs, control servo motors (analogWrite()).

**Important Notes**
* A4 (SDA) and A5 (SCL) are also used for I²C communication.
* Avoid using D0/D1 if using serial (UART) communication.