# Arduino Nano 33 IoT: specs and pinout

> Nano-format board with an ATSAMD21G18A Arm Cortex-M0+ processor, a NINA-W102 Wi-Fi and Bluetooth LE module, a 6-axis IMU and a crypto chip. It runs…

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Nano-format board with an ATSAMD21G18A Arm Cortex-M0+ processor, a NINA-W102 Wi-Fi and Bluetooth LE module, a 6-axis IMU and a crypto chip. It runs at 3.3 V.

Every value cites its sourceOfficial pinout

[Buy on Compoden](https://compoden.com/products/arduino-nano-33-iot)

## Specs

| Spec | Value | Source |
|---|---|---|
| Processor | ATSAMD21G18A Arm Cortex-M0+, up to 48 MHz | Arduino official documentation Section 3.2 Processor, p.7 |
| Flash | 256 kB | Arduino official documentation Features, p.2 |
| Wi-Fi / Bluetooth | NINA-W102 module: IEEE 802.11 b/g/n, 2.4 GHz; Bluetooth BR/EDR and Bluetooth Low Energy | Arduino official documentation Features, p.3 |
| I/O voltage | 3.3 V only; NOT 5 V tolerant; the 5V pin does not supply voltage (it connects to USB power through a jumper) | Arduino official documentation Section 1 The Board, p.5 |
| Maximum input voltage | -0.3 V to 21 V on the VIN pad (also listed for USB) | Arduino official documentation Section 2.2 Power Consumption, p.5 |
| Operating temperature | -40 C to 85 C (conservative thermal limits for the whole board) | Arduino official documentation Section 2.1, p.5 |
| ADC / DAC | 12-bit 350 ksps ADC (up to 16 bit with oversampling); 10-bit 350 ksps DAC | Arduino official documentation Features, p.2 |
| IMU | 6-axis IMU (the datasheet names two parts: LSM6DSOX on the board topology and LSM6DSL in the feature and library lists) | Arduino official documentation Section 3.1 Board Topology U3, p.6; Section 3.5, p.8 |
| Communication | 6x SERCOM (USART, I2C, SPI, LIN); full-speed USB host/device; two-channel I2S | Arduino official documentation Features, p.2 |

## Power

| | Value | Source |
|---|---|---|
| Supply | USB, VIN or VUSB pins; maximum input 21 V | Arduino official documentation Section 2.2, p.5: PMax listed as TBC |

## Pinout

Pin rows are from the official Arduino Nano 33 IoT datasheet (SKU ABX00027). The header pin table is identical to the one in the Nano 33 BLE Sense datasheet.

| Pin | Function | Voltage | Notes | Source |
|---|---|---|---|---|
| 1 | D13 | 3.3 V logic | GPIO | Arduino official documentation Section 5.2 Headers, p.11 |
| 2 | +3V3 | 3.3 V | Internally generated power output to external devices | Arduino official documentation Section 5.2 Headers, p.11 |
| 3 | AREF | 3.3 V logic | Analog Reference; can be used as GPIO | Arduino official documentation Section 5.2 Headers, p.11 |
| 4 | A0/DAC0 | 3.3 V logic | ADC in/DAC out; can be used as GPIO | Arduino official documentation Section 5.2 Headers, p.11 |
| 5 | A1 | 3.3 V logic | ADC in; can be used as GPIO | Arduino official documentation Section 5.2 Headers, p.11 |
| 6 | A2 | 3.3 V logic | ADC in; can be used as GPIO | Arduino official documentation Section 5.2 Headers, p.11 |
| 7 | A3 | 3.3 V logic | ADC in; can be used as GPIO | Arduino official documentation Section 5.2 Headers, p.11 |
| 8 | A4/SDA | 3.3 V logic | ADC in; I2C SDA; Can be used as GPIO A4/A5 have an internal pull-up and default to I2C | Arduino official documentation Section 5.2 Headers, p.11 |
| 9 | A5/SCL | 3.3 V logic | ADC in; I2C SCL; Can be used as GPIO A4/A5 have an internal pull-up and default to I2C | Arduino official documentation Section 5.2 Headers, p.11 |
| 10 | A6 | 3.3 V logic | ADC in; can be used as GPIO | Arduino official documentation Section 5.2 Headers, p.11 |
| 11 | A7 | 3.3 V logic | ADC in; can be used as GPIO | Arduino official documentation Section 5.2 Headers, p.11 |
| 12 | VUSB | | Normally NC; can be connected to VUSB pin of the USB connector by shorting a jumper | Arduino official documentation Section 5.2 Headers, p.11 |
| 13 | RST | | Active low reset input (duplicate of pin 18) | Arduino official documentation Section 5.2 Headers, p.11 |
| 14 | GND | | Power Ground | Arduino official documentation Section 5.2 Headers, p.11 |
| 15 | VIN | | Vin Power input | Arduino official documentation Section 5.2 Headers, p.11 |
| 16 | TX | 3.3 V logic | USART TX; can be used as GPIO | Arduino official documentation Section 5.2 Headers, p.11 |
| 17 | RX | 3.3 V logic | USART RX; can be used as GPIO | Arduino official documentation Section 5.2 Headers, p.11 |
| 18 | RST | | Active low reset input (duplicate of pin 13) | Arduino official documentation Section 5.2 Headers, p.11 |
| 19 | GND | | Power Ground | Arduino official documentation Section 5.2 Headers, p.11 |
| 20 | D2 | 3.3 V logic | GPIO | Arduino official documentation Section 5.2 Headers, p.11 |
| 21 | D3/PWM | 3.3 V logic | GPIO; can be used as PWM | Arduino official documentation Section 5.2 Headers, p.11 |
| 22 | D4 | 3.3 V logic | GPIO | Arduino official documentation Section 5.2 Headers, p.11 |
| 23 | D5/PWM | 3.3 V logic | GPIO; can be used as PWM | Arduino official documentation Section 5.2 Headers, p.11 |
| 24 | D6/PWM | 3.3 V logic | GPIO, can be used as PWM | Arduino official documentation Section 5.2 Headers, p.11 |
| 25 | D7 | 3.3 V logic | GPIO | Arduino official documentation Section 5.2 Headers, p.11 |
| 26 | D8 | 3.3 V logic | GPIO | Arduino official documentation Section 5.2 Headers, p.11 |
| 27 | D9/PWM | 3.3 V logic | GPIO; can be used as PWM | Arduino official documentation Section 5.2 Headers, p.11 |
| 28 | D10/PWM | 3.3 V logic | GPIO; can be used as PWM | Arduino official documentation Section 5.2 Headers, p.11 |
| 29 | D11/MOSI | 3.3 V logic | SPI MOSI; can be used as GPIO | Arduino official documentation Section 5.2 Headers, p.11 |
| 30 | D12/MISO | 3.3 V logic | SPI MISO; can be used as GPIO | Arduino official documentation Section 5.2 Headers, p.11 |

## Build with it
Project ideas for the Arduino Nano 33 IoT. Each link opens Soldr with the prompt filled in; Soldr assigns the pins, checks power and shows how to wire every part.

- [Wi-Fi temperature logger](https://app.soldr.ai/?prompt=I%20want%20to%20build%20a%20Wi-Fi%20temperature%20logger%20with%20an%20Arduino%20Nano%2033%20IoT%20and%20a%20DS18B20%20temperature%20sensor): The board has built-in Wi-Fi; a digital 1-Wire sensor needs one pin and runs from the 3.3 V pin, matching the board's 3.3 V I/O.
- [Wi-Fi plant moisture monitor](https://app.soldr.ai/?prompt=I%20want%20to%20build%20a%20Wi-Fi%20plant%20moisture%20monitor%20with%20an%20Arduino%20Nano%2033%20IoT%20and%20a%20capacitive%20soil%20moisture%20sensor): Power the sensor from 3.3 V so its analog output stays within the board's 3.3 V logic level; the 12-bit ADC reads it.
- [Weather node with display](https://app.soldr.ai/?prompt=I%20want%20to%20build%20a%20Wi-Fi%20weather%20node%20with%20an%20Arduino%20Nano%2033%20IoT%2C%20a%20BMP280%20sensor%20and%20a%200.96%20inch%20OLED): Both modules use I2C on A4/A5 at 3.3 V; Wi-Fi sends readings out. Check each module's supply and logic level.
- [Shake and tilt alert logger](https://app.soldr.ai/?prompt=I%20want%20to%20build%20a%20shake%20and%20tilt%20event%20logger%20with%20an%20Arduino%20Nano%2033%20IoT%20using%20its%20on-board%20IMU%20and%20an%20LED): The 6-axis IMU is on the board; the LED needs a series resistor. Learning project.

## Common mistakes

- Connecting 5 V signals: the board supports 3.3 V I/O only and is not 5 V tolerant (source: Arduino official documentation Section 1)
- Expecting the 5V pin to output 5 V: it is connected to USB power through a jumper and does not supply voltage (source: Arduino official documentation Section 1)
- Using A4 or A5 as analog inputs: they have an internal pull-up and default to I2C (source: Arduino official documentation Section 3.2)

## Not covered by the official source

- Supply current is listed TBC in the datasheet.
- The Features list shows '32 kB Flash' as a second memory line, which may be a mislabelled SRAM figure; SRAM is not stated.
- Radio values are only those printed in the Arduino datasheet; the NINA-W102 module datasheet is not covered here.
- The datasheet contradicts itself on the IMU part: LSM6DSOX (Section 3.1 board topology, BOM U3) and LSM6DSL (feature list and library table). The part is not stated here; use the 6-axis IMU library that matches your board.

## Sources

- Arduino official documentation (Arduino Nano 33 IoT User Manual, SKU ABX00027, modified 07/11/2026)