Arduino Nano (A000005, original): specs and pinout
Original Arduino Nano: breadboard-format ATmega328 board with a Mini-B USB port, 8 analog inputs and 5 V logic.
Specs
| Spec | Value | Source |
|---|---|---|
| Microcontroller | ATmega328 at 16 MHz (the memory line of the Tech Specs names ATmega328P) | Arduino datasheet A000005 Datasheet p.1 Description and p.2 Features; Tech Specs: Microcontroller, Clock speed |
| Memory | 32 KB flash (2 KB used by the bootloader), 2 KB SRAM, 1 KB EEPROM | Arduino datasheet A000005 Datasheet p.2 Features; Tech Specs: Memory |
| I/O voltage | 5 V | Arduino official documentation Tech Specs: Power |
| Input voltage | 7-12 V nominal (Tech Specs); the pinout sheet states 'VIN 7-12 V input to the board'; the datasheet feature list says 7-15 V unregulated | Arduino datasheet A000005 Pinout PDF A000005, page 1, note; Tech Specs: Power; datasheet p.2 |
| DC current per I/O pin | 20 mA maximum per I/O pin | Arduino datasheet A000005 Pinout PDF A000005, page 1, warning box; Tech Specs: Power |
| Current from 3.3 V pin | 50 mA maximum | Arduino datasheet A000005 Pinout PDF A000005, page 1, warning box |
| Pins | 14 digital I/O (6 PWM) and 8 analog inputs in the Tech Specs; the datasheet feature list says 20 digital, 8 analog, 6 PWM | Arduino official documentation Tech Specs: Pins; datasheet p.2 Features |
| Communication | UART on RX/TX; I2C on A4 (SDA) and A5 (SCL); SPI on D11 (COPI), D12 (CIPO), D13 (SCK) with any GPIO as chip select | Arduino official documentation Tech Specs: Communication |
| USB connector | Mini-B USB | Arduino official documentation Tech Specs: USB connector |
| Operating temperature | -40 to 85 C (conservative thermal limits for the whole board) | Arduino datasheet A000005 Datasheet p.5, section 2.1 |
Power
| Value | Source | |
|---|---|---|
| Supply | Mini-B USB 5 V, or VIN 7-12 V (the datasheet feature list says 7-15 V unregulated) | Arduino datasheet A000005 Datasheet p.2 Features and p.5 (the power consumption rows read TBC); Tech Specs: Power |
Pinout
Rows come from the official Nano full pinout sheet (A000005, last update 30/06/2021): left and right columns are listed from the top (USB end) downward, as drawn. This is the official Arduino Nano, so the official documents apply.
| Pin | Function | Voltage | Notes | Source |
|---|---|---|---|---|
| Left 1 (top view, USB end at top) | D13 | 5 V logic | PB5; SPI SCK; also LED_BUILTIN | Arduino datasheet A000005 Pinout PDF A000005, page 1 |
| Left 2 (top view, USB end at top) | +3V3 | 3.3 V | power output; 50 mA maximum | Arduino datasheet A000005 Pinout PDF A000005, page 1 |
| Left 3 (top view, USB end at top) | AREF | Arduino datasheet A000005 Pinout PDF A000005, page 1 | ||
| Left 4 (top view, USB end at top) | A0 / D14 | 5 V logic | PC0; ADC[0] | Arduino datasheet A000005 Pinout PDF A000005, page 1 |
| Left 5 (top view, USB end at top) | A1 / D15 | 5 V logic | PC1; ADC[1] | Arduino datasheet A000005 Pinout PDF A000005, page 1 |
| Left 6 (top view, USB end at top) | A2 / D16 | 5 V logic | PC2; ADC[2] | Arduino datasheet A000005 Pinout PDF A000005, page 1 |
| Left 7 (top view, USB end at top) | A3 / D17 | 5 V logic | PC3; ADC[3] | Arduino datasheet A000005 Pinout PDF A000005, page 1 |
| Left 8 (top view, USB end at top) | A4 / D18 | 5 V logic | PC4; ADC[4]; I2C SDA | Arduino datasheet A000005 Pinout PDF A000005, page 1 |
| Left 9 (top view, USB end at top) | A5 / D19 | 5 V logic | PC5; ADC[5]; I2C SCL | Arduino datasheet A000005 Pinout PDF A000005, page 1 |
| Left 10 (top view, USB end at top) | A6 | 5 V logic | ADC[6]; the sheet gives no digital pin number | Arduino datasheet A000005 Pinout PDF A000005, page 1 |
| Left 11 (top view, USB end at top) | A7 | 5 V logic | ADC[7]; the sheet gives no digital pin number | Arduino datasheet A000005 Pinout PDF A000005, page 1 |
| Left 12 (top view, USB end at top) | +5V | 5 V | power | Arduino datasheet A000005 Pinout PDF A000005, page 1 |
| Left 13 (top view, USB end at top) | RESET | PC6 | Arduino datasheet A000005 Pinout PDF A000005, page 1 | |
| Left 14 (top view, USB end at top) | GND | 0 V | Arduino datasheet A000005 Pinout PDF A000005, page 1 | |
| Left 15 (top view, USB end at top) | VIN | 7-12 V input | Arduino datasheet A000005 Pinout PDF A000005, page 1 | |
| Right 1 | D12 | 5 V logic | PB4; SPI CIPO | Arduino datasheet A000005 Pinout PDF A000005, page 1 |
| Right 2 | ~D11 | 5 V logic | PB3; PWM; SPI COPI | Arduino datasheet A000005 Pinout PDF A000005, page 1 |
| Right 3 | ~D10 | 5 V logic | PB2; PWM | Arduino datasheet A000005 Pinout PDF A000005, page 1 |
| Right 4 | ~D9 | 5 V logic | PB1; PWM | Arduino datasheet A000005 Pinout PDF A000005, page 1 |
| Right 5 | D8 | 5 V logic | PB0 | Arduino datasheet A000005 Pinout PDF A000005, page 1 |
| Right 6 | D7 | 5 V logic | PD7 | Arduino datasheet A000005 Pinout PDF A000005, page 1 |
| Right 7 | ~D6 | 5 V logic | PD6; PWM | Arduino datasheet A000005 Pinout PDF A000005, page 1 |
| Right 8 | ~D5 | 5 V logic | PD5; PWM | Arduino datasheet A000005 Pinout PDF A000005, page 1 |
| Right 9 | D4 | 5 V logic | PD4 | Arduino datasheet A000005 Pinout PDF A000005, page 1 |
| Right 10 | ~D3 | 5 V logic | PD3; PWM | Arduino datasheet A000005 Pinout PDF A000005, page 1 |
| Right 11 | D2 | 5 V logic | PD2 | Arduino datasheet A000005 Pinout PDF A000005, page 1 |
| Right 12 | GND | 0 V | Arduino datasheet A000005 Pinout PDF A000005, page 1 | |
| Right 13 | RESET | PC6 | Arduino datasheet A000005 Pinout PDF A000005, page 1 | |
| Right 14 | D0 / RX | 5 V logic | PD0 | Arduino datasheet A000005 Pinout PDF A000005, page 1 |
| Right 15 | D1 / TX | 5 V logic | PD1 | Arduino datasheet A000005 Pinout PDF A000005, page 1 |
| On-board LED | LED_BUILTIN | PB5 | Arduino datasheet A000005 Pinout PDF A000005, page 1 |
Build with it
Project ideas for the Arduino Nano (A000005, original). Each link opens Soldr with the prompt filled in; Soldr assigns the pins, checks power and shows how to wire every part.
- Pocket temperature and humidity display: The Nano runs at 5 V and powers the DHT22 (3.3 V to 6 V) and the LCD backpack from its 5 V pin; the LCD uses A4 and A5. Check the LCD module's supply on its silkscreen. Learning project.
- Parking distance display: The HC-SR04 needs 5 V (15 mA) and has a TTL echo, matching the Nano's 5 V I/O. Trigger and echo use two digital pins, the LCD uses A4 and A5.
- Keypad code entry demo: The 4x4 keypad needs eight digital pins and the I2C LCD needs A4 and A5, which fits the Nano's pins. It is a demo, not a security lock.
Common mistakes
- Feeding VIN outside the stated range: the pinout sheet and Tech Specs say 7-12 V, the datasheet feature list says 7-15 V, so stay at 7-12 V (source: Arduino datasheet A000005)
- Using A6 or A7 as digital pins: the pinout sheet shows them as analog inputs only, with no digital pin number (source: Arduino datasheet A000005 page 1)
- Drawing more than 50 mA from the 3.3 V pin or more than 20 mA from an I/O pin (source: Arduino datasheet A000005 page 1)
Not covered by the official source
- The datasheet and Tech Specs disagree on the VIN range (7-15 V vs 7-12 V) and on the digital pin count (20 vs 14); both are shown.
- The datasheet names the chip ATmega328; the Tech Specs memory line names ATmega328P.
- The datasheet's power consumption rows read TBC.
Sources
- Arduino datasheet A000005 (Nano User Manual, A000005, revision 5, modified 07/11/2026)
- Arduino datasheet A000005 (Nano full pinout, last update 30/06/2021)
- Arduino official documentation (Arduino Nano hardware page, Tech Specs)