Arduino Nano V3 interactive pinout

UART RX (D0)

1. Function: Receiving UART data
2. Type: Digital Input/Output
3. Used for serial communication and board programming
4. Can be used for external interrupts (INT0)
5. Maximum current: 20mA (recommended not more than 10mA)
6. Voltage: 0-5V (TTL logic levels)

UART TX (D1)

1. Function: Transmitting UART data
2. Type: Digital Input/Output
3. Used for serial communication and board programming
4. Can be used for external interrupts (INT1)
5. Maximum current: 20mA (recommended not more than 10mA)
6. Voltage: 0-5V (TTL logic levels)

Digital Pin 2 (D2)

1. Function: General-purpose Digital Input/Output
2. Supports external interrupts (INT0)
3. Maximum output current: 40mA (total for all digital pins not more than 200mA)
4. Input resistance: ~100 MΩ
5. Can be used for buttons, sensors, relays, and other digital devices

Digital Pin 3 (D3)

1. Function: Digital Input/Output with PWM
2. Supports external interrupts (INT1)
3. PWM frequency: ~490Hz (default)
4. PWM resolution: 8-bit (0-255)
5. Ideal for controlling servos, LEDs, motors

Digital Pin 4 (D4)

1. Function: General-purpose Digital Input/Output
2. Can be used as an output for digital sensors
3. Can work as an input for buttons, limit switches
4. Internal pull-up resistor 20-50kΩ (activated programmatically)
5. Compatible with 3.3V and 5V devices

Digital Pin 5 (D5)

1. Function: Digital Input/Output with PWM
2. PWM frequency: ~980Hz (default)
3. Can be used for motor speed control (via driver)
4. Supports Timer/Counter mode
5. Compatible with most shields and modules

Digital Pin 6 (D6)

1. Function: Digital Input/Output with PWM
2. PWM frequency: ~980Hz (default)
3. Can work as an output for analog devices via PWM
4. Supports Timer/Counter mode
5. Maximum switching speed: ~4MHz

Digital Pin 7 (D7)

1. Function: General-purpose Digital Input/Output
2. No special functions (pure digital pin)
3. Recommended for simple tasks – buttons, LEDs, relays
4. Input Voltage: 0-5V (TTL logic levels)
5. Short-circuit protection: yes (current limiting)

Digital Pin 8 (D8)

1. Function: General-purpose Digital Input/Output
2. Can be used as an input for digital sensors
3. Suitable for connecting buttons with a pull-up resistor
4. Switching time: <4μs
5. Compatible with 3.3V logic (but better to use a level converter)

Digital Pin 9 (D9)

1. Function: Digital Input/Output with PWM
2. PWM frequency: ~490Hz (default)
3. Used for servo control (with the Servo library)
4. Can work as an output for analog signals
5. Supports Timer/Counter mode

Digital Pin 10 (D10)

1. Function: Digital Input/Output with PWM
2. Primary Slave Select (SS) pin for SPI interface
3. PWM frequency: ~490Hz (default)
4. Used for connecting SPI devices (SD cards, displays)
5. Can work as a regular digital pin

Digital Pin 11 (D11)

1. Function: Digital Input/Output with PWM
2. Primary MOSI (Master Out Slave In) pin for SPI interface
3. PWM frequency: ~980Hz (default)
4. Used for data transmission over SPI
5. Maximum SPI speed: 8MHz (at 16MHz clock frequency)

Digital Pin 12 (D12)

1. Function: Digital Input/Output
2. Primary MISO (Master In Slave Out) pin for SPI interface
3. Used for data reception over SPI
4. Input resistance: ~100 MΩ
5. No PWM, but supports high-speed data transfer

Digital Pin 13 (D13)

1. Function: Digital Input/Output
2. Primary SCK (Serial Clock) pin for SPI interface
3. Connected to the built-in LED on the board (usually via a resistor)
4. Used for clocking SPI devices
5. Not recommended for time-critical tasks due to the connected LED

AREF (Analog Reference)

1. Function: Pin for supplying external ADC reference voltage
2. Location: Near analog pins (A0-A7), usually labeled “AREF” or “REF”
3. Functions:
   • Sets the upper measurement limit for analog inputs (default 5V)
   • Allows for increased measurement accuracy for small voltages
   • Supports internal sources 1.1V (ATmega328) and 2.56V (ATmega168)
4. Technical specifications:
   • External voltage range: 0-5V (do not exceed VCC!)
   • Input resistance: ~32kΩ
   • Recommended current: no more than 1mA
5. Usage:
   • For precise measurements of sensors with low output voltage
   • When working with 3.3V devices (as reference voltage)
   • In low-power consumption circuits
6. Important:
   • Before use, call analogReference(EXTERNAL)
   • Do not connect a source >5V – may damage the microcontroller
   • For internal sources, use analogReference(INTERNAL)

Code example:

				void setup() {
	analogReference(EXTERNAL); // Use external reference voltage
		pinMode(A0, INPUT);
	}

	void loop() {
		int sensorValue = analogRead(A0); // Read with AREF reference voltage
	}
			

A0 (Analog Input / Digital Pin)

1. ADC resolution: 10-bit (0-1023)
2. Voltage: 0-5V (default), reference can be changed
3. Maximum sampling rate: ~10kHz
4. Input resistance: ~100 MΩ
5. Can be used as a digital pin (D14)

A1 (Analog Input / Digital Pin)

1. ADC resolution: 10-bit (0-1023)
2. Reference voltage: default VCC (5V)
3. Can be used for potentiometers, analog sensors
4. Digital pin (D15) with full functionality
5. Conversion time: ~100μs

A2 (Analog Input / Digital Pin)

1. ADC resolution: 10-bit (0-1023)
2. Can be used for voltage measurement (up to 5V)
3. Digital pin (D16) with support for all functions
4. Suitable for temperature, light, pressure sensors
5. Input protected from overvoltage (but not from reverse polarity)

A3 (Analog Input / Digital Pin)

1. ADC resolution: 10-bit (0-1023)
2. Reference voltage can be changed to internal 1.1V or external
3. Digital pin (D17) with full functionality
4. Suitable for precise measurements with proper calibration
5. Measurement error: ±2 LSB

A4 (Analog Input / Digital Pin / SDA)

1. ADC resolution: 10-bit (0-1023)
2. Data line (SDA) for I2C interface
3. Digital pin (D18) with support for all functions
4. Pull-up resistors for I2C must be external (2.2kΩ-10kΩ)
5. I2C frequency: up to 400kHz (Fast Mode)

A5 (Analog Input / Digital Pin / SCL)

1. ADC resolution: 10-bit (0-1023)
2. Clock line (SCL) for I2C interface
3. Digital pin (D19) with support for all functions
4. Used for connecting I2C devices (displays, sensors)
5. I2C addressing: 7-bit (up to 127 devices)

A6 (Analog Input)

1. ADC resolution: 10-bit (0-1023)
2. Analog input only (cannot be used as digital)
3. Voltage: 0-5V (default)
4. Suitable for analog sensors with constant signal
5. Input resistance: ~100 MΩ

A7 (Analog Input)

1. ADC resolution: 10-bit (0-1023)
2. Analog input only (cannot be used as digital)
3. Voltage: 0-5V (default)
4. Can be used for battery voltage measurement
5. Measurement error: ±2 LSB

VIN (Input Voltage)

1. Function: Input voltage for the board
2. Range: 7-12V (recommended), maximum 6-20V
3. Used when powered by an external source (not USB)
4. Connected to the 5V regulator on the board
5. Maximum current: depends on the regulator (usually up to 1A)

5V Output

1. Function: Output of regulated 5V voltage
2. Source: USB or regulator from VIN
3. Maximum current: ~500mA (when powered by USB)
4. Used to power external devices
5. Overload protection: yes (but better not to abuse)

3.3V Output

1. Function: Output of regulated 3.3V voltage
2. Generated by a separate regulator on the board
3. Maximum current: ~150mA (limited by the regulator)
4. Used for 3.3V devices (modules, sensors)
5. Unstable under heavy loads

GND (SPI Ground)

1. Function: Common ground
2. Connected to all other GND on the board
3. Especially important for SPI devices (provides common potential)
4. Always connected last and disconnected first
5. Recommended to use a separate wire for precise measurements

GND (Ground)

1. Function: Common ground
2. Connected to all other GND on the board
3. Used for closing electrical circuits
4. Mandatory for connecting all external devices
5. Has no voltage relative to other GND

GND (Digital Ground)

1. Function: Common ground for digital circuits
2. Connected to all other GND on the board
3. Recommended for digital devices (buttons, LEDs)
4. Better not to use for analog sensors (may have noise)
5. All GND on the board are interconnected

MISO (Master In Slave Out)

1. Function: Data line from slave to master
2. Used in the SPI interface
3. Speed: up to 8MHz (with 16MHz processor)
4. Connected to pin D12 (can be reassigned)
5. Used for SD cards, displays, RFID modules

MOSI (Master Out Slave In)

1. Function: Data line from master to slave
2. Used in the SPI interface
3. Speed: up to 8MHz (with 16MHz processor)
4. Connected to pin D11 (can be reassigned)
5. Used for command and data transmission

SCK (Serial Clock)

1. Function: Clock signal for SPI
2. Generated by the master device (Arduino)
3. Speed: up to 8MHz (with 16MHz processor)
4. Connected to pin D13 (can be reassigned)
5. Synchronizes data transmission over SPI

RESET

1. Function: Microcontroller reset
2. Active low (triggers when shorted to GND)
3. Connected to the RESET button on the board
4. Can be used for external reset
5. Does not require a pull-up resistor (present on the board)

RX LED

1. Function: UART data reception indicator
2. Connected via a current-limiting resistor
3. Blinks when receiving data via USB/UART
4. Color: usually green (depends on board version, mine is red)
5. Not recommended to disable (used for diagnostics)

TX LED

1. Function: UART data transmission indicator
2. Connected via a current-limiting resistor
3. Blinks when transmitting data via USB/UART
4. Color: usually green (depends on board version, mine is red)
5. Not recommended to disable (used for diagnostics)

Built-in Programmable LED

1. Function: User-controllable built-in LED.
2. Connected via a current-limiting resistor
3. Blinks 1-2 times when the microcontroller starts.
4. Can be turned on and off by command on pin 13. Signal HIGH – LED off, LOW – LED on.
5. Color: usually green (depends on board version, mine is red)
6. Not recommended to disable (used for microcontroller startup diagnostics)

Power Indicator

1. Function: Board power indicator
2. Connected via a current-limiting resistor
3. Turns on when power is connected to the board
4. Color: usually green (depends on board version, mine is red)
5. Can be desoldered to reduce current consumption

RX LED Resistor

1. Function: Current-limiting resistor for RX LED
2. Value: usually 220 Ω (depends on board version)
3. Protects the LED from burning out
4. Not recommended to change/replace
5. Provides correct current through the LED (~10-15mA)

TX LED Resistor

1. Function: Current-limiting resistor for TX LED
2. Value: usually 220 Ω (depends on board version)
3. Protects the LED from burning out
4. Not recommended to change/replace
5. Provides correct current through the LED (~10-15mA)

Power LED Resistor

1. Function: Current-limiting resistor for Power LED
2. Value: usually 220 Ω (depends on board version)
3. Protects the LED from burning out
4. Not recommended to change/replace
5. Provides correct current through the LED (~10-15mA)

Built-in LED Resistor

1. Function: Current-limiting resistor for Built-in LED
2. Value: usually 220 Ω (depends on board version)
3. Protects the LED from burning out
4. Not recommended to change/replace
5. Provides correct current through the LED (~10-15mA)

ATmega328PB

1. Function: Main board microcontroller
2. Architecture: 8-bit AVR
3. Clock frequency: 16MHz (external crystal)
4. Memory: 32KB Flash, 2KB SRAM, 1KB EEPROM
5. Enhanced version of ATmega328P with additional peripherals

16MHz Crystal

1. Function: Clock frequency generator
2. Frequency: 16MHz ±0.5%
3. Accuracy: better than internal RC oscillator
4. Necessary for precise operation of UART, SPI, timers
5. Connected to XTAL1/XTAL2 pins of the microcontroller

RESET Button

1. Function: Microcontroller reset button
2. Connected to the RESET pin of the ATmega via a resistor
3. Active low (triggers when pressed)
4. No debounce protection (filtering is software-based)
5. Allows restarting the program without power cycling

USB Type-C

1. Function: Interface for programming and power
2. USB version: 2.0 Full-Speed (12Mbps)
3. USB-UART converter: CH340G or similar
4. Power: 5V, up to 500mA (without additional devices)
5. Supports hot-plugging (but better to turn off before connecting)