# Nano R3 (ATmega328P): specs and pinout

> Compact Arduino Nano-compatible board based on the ATmega328P, with a CH340 USB-to-serial chip and a Mini USB cable.

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Compact Arduino Nano-compatible board based on the ATmega328P, with a CH340 USB-to-serial chip and a Mini USB cable.

Every value cites its sourceOfficial pinout

[Buy on Compoden](https://compoden.com/products/nano-r3-ch340-development-board-with-usb-cable-compatible-with-arduino)

## Specs

| Spec | Value | Source |
|---|---|---|
| Microcontroller | ATmega328 | Arduino datasheet A000005 |
| Operating voltage | 5 V | Arduino datasheet A000005 |
| VIN input voltage | 7V-12V | Arduino datasheet A000005 |
| External 5V regulated input | pin 27 (5V regulated external power supply) | Arduino datasheet A000005 |
| Flash | 32 kB (of which 2 KB used by bootloader) | Arduino datasheet A000005 |
| SRAM | 2 kB | Arduino datasheet A000005 |
| EEPROM | 1 kB | Arduino datasheet A000005 |
| Clock speed | 16 MHz | Arduino datasheet A000005 |
| Digital I/O | 20 Digital | Arduino datasheet A000005 |
| Analog inputs | 8 Analog | Arduino datasheet A000005 |
| PWM outputs | 6 PWM Output | Arduino datasheet A000005 |
| Serial | Programmable Serial USART; Master/Slave SPI; I2C (TWI) | Arduino datasheet A000005 |
| USB | Mini-B USB connection (listing: Mini USB cable) | Arduino datasheet A000005 |

## Power

| | Value | Source |
|---|---|---|
| Supply | USB Mini-B, or VIN 7V-12V, or regulated 5V on pin 27 (datasheet features list 7-15V unregulated on pin 30) | Arduino datasheet A000005 |

## Pinout

| Pin | Function | Voltage | Notes | Source |
|---|---|---|---|---|
| +3V3 | Power | 3.3 V | Datasheet table row 1 is labelled '+3V3' with description '5V USB Power' (conflict; see gaps) | Arduino datasheet A000005 |
| A0 | Analog input 0 /GPIO | | | Arduino datasheet A000005 |
| A1 | Analog input 1 /GPIO | | | Arduino datasheet A000005 |
| A2 | Analog input 2 /GPIO | | | Arduino datasheet A000005 |
| A3 | Analog input 3 /GPIO | | | Arduino datasheet A000005 |
| A4 | Analog input 4 /GPIO | | | Arduino datasheet A000005 |
| A5 | Analog input 5 /GPIO | | | Arduino datasheet A000005 |
| A6 | Analog input 6 /GPIO | | | Arduino datasheet A000005 |
| A7 | Analog input 7 /GPIO | | | Arduino datasheet A000005 |
| +5V | +5V Power Rail | 5 V | | Arduino datasheet A000005 |
| Reset | Reset | | | Arduino datasheet A000005 |
| GND | Ground | | | Arduino datasheet A000005 |
| VIN | Voltage Input | 7V-12V | Power tree prints RANGE 7V-12V | Arduino datasheet A000005 |
| D1/TX1 | Digital Input 1 /GPIO | | | Arduino datasheet A000005 |
| D0/RX0 | Digital Input 0 /GPIO | | | Arduino datasheet A000005 |
| D2 | Digital Input 2 /GPIO | | | Arduino datasheet A000005 |
| D3 | Digital Input 3 /GPIO | | | Arduino datasheet A000005 |
| D4 | Digital Input 4 /GPIO | | | Arduino datasheet A000005 |
| D5 | Digital Input 5 /GPIO | | | Arduino datasheet A000005 |
| D6 | Digital Input 6 /GPIO | | | Arduino datasheet A000005 |
| D7 | Digital Input 7 /GPIO | | | Arduino datasheet A000005 |
| D8 | Digital Input 8 /GPIO | | | Arduino datasheet A000005 |
| D9 | Digital Input 9 /GPIO | | | Arduino datasheet A000005 |
| D10 | Digital Input 10 /GPIO | | | Arduino datasheet A000005 |
| D11 | Digital Input 11 /GPIO | | | Arduino datasheet A000005 |
| D12 | Digital Input 12 /GPIO | | | Arduino datasheet A000005 |
| D13 | Digital Input 13 /GPIO | | | Arduino datasheet A000005 |

## Common mistakes

- Feeding VIN outside 7V-12V as shown in the power tree [Arduino datasheet A000005]
- Trusting pin 1's label: the datasheet table prints '+3V3' with description '5V USB Power'; check the board before wiring 3.3 V or 5 V to that pad [Arduino datasheet A000005]
- Treating the 3.3 V regulator as a supply for high-current parts: the power tree shows its FT232RL LDO is limited to a max of 50 mA [Arduino datasheet A000005]

## What we could not confirm

- Compatible board: the listing names a CH340 USB chip; the official Nano datasheet describes an FT232RL USB chip. Pinout taken from the official Arduino Nano; the clone's layout is not confirmed.
- Conflict: power input - datasheet power tree says VIN 7V-12V; datasheet features say 7-15V unregulated (pin 30). Both are recorded as printed.
- Conflict: datasheet pin 1 label '+3V3' vs description '5V USB Power' in the same table.
- Max current per I/O pin: not in the official datasheet. Listing says avoid more than 40mA per I/O pin; not verified against an official source, so not used.
- Chip marking: listing says ATmega328P; official datasheet says ATmega328 (power tree names ATMEGA328P-32MUR). Clone chip marking not confirmed.
- Typical current draw: official datasheet shows TBC values.

## Sources

- Arduino datasheet A000005
- [link](https://compoden.com/products/nano-r3-ch340-development-board-with-usb-cable-compatible-with-arduino)

Building with the Nano R3 (ATmega328P)? [Describe your project on Soldr](https://app.soldr.ai): it assigns pins from the board's published pinout, checks power and logic levels, and shows how to wire every part.