# Arduino Micro > Smallest official Arduino with native USB, based on ATmega32u4 at 16 MHz. Breadboard-friendly at 48×18mm with 20 I/O pins, 12 analog inputs, and USB HID/CDC emulation capability. ## Quick Facts - **Brand:** Arduino - **Board Type:** dev-board - **Price:** ~$21.8 - **Product Readiness:** developer - **CPU:** ATmega32u4 @ 16 MHz - **CPU Architecture:** AVR - **CPU Cores:** 1 - **RAM:** 2.5 KB - **Flash:** 32 KB - **Power:** 5V via Micro USB or 7-12V Vin pin - **Operating Voltage:** 5V - **Dimensions:** 48 × 18 mm - **Weight:** 6.5g - **SD Card:** No ## Open Source - **Firmware:** Yes - **Schematics:** Yes - **PCB Layout:** Yes ## Compatible Firmware arduino, platformio ## Use Cases - usb-hid - wearable - prototyping - embedded-development - robotics ## Components - **ATmega32u4** (mcu): 8-bit AVR microcontroller with native USB at 16 MHz, 32KB flash, 2.5KB SRAM, 1KB EEPROM — [Datasheet](https://openhardware.directory/r?to=https%3A%2F%2Fww1.microchip.com%2Fdownloads%2Fen%2FDeviceDoc%2FAtmel-7766-8-bit-AVR-ATmega16U4-32U4_Datasheet.pdf&ref=openhardware.directory&product=arduino-micro&source=md-export) ## Protocols - **UART**: TX: D1, RX: D0 - **SPI**: MOSI: D16, MISO: D14, SCK: D15, SS: D10 - **I2C**: SDA: D2, SCL: D3 - **USB** - **ICSP** ## GPIO Map | Pin | Name | Type | Functions | |-----|------|------|-----------| | D0 | UART RX, External Interrupt 2 | UART | digital-input, digital-output, interrupt | | D1 | UART TX, External Interrupt 3 | UART | digital-input, digital-output, interrupt | | D2 | I2C SDA, External Interrupt 1 | I2C | digital-input, digital-output, interrupt | | D3 | I2C SCL, PWM, External Interrupt 0 | I2C | digital-input, digital-output, pwm, interrupt | | D4 | Digital I/O, Analog Input (A6) | — | digital-input, digital-output, analog-input | | D5 | Digital I/O, PWM | — | digital-input, digital-output, pwm | | D6 | Digital I/O, Analog Input (A7), PWM | — | digital-input, digital-output, analog-input, pwm | | D7 | Digital I/O, External Interrupt 6 | — | digital-input, digital-output, interrupt | | D8 | Digital I/O, Analog Input (A8) | — | digital-input, digital-output, analog-input | | D9 | Digital I/O, Analog Input (A9), PWM | — | digital-input, digital-output, analog-input, pwm | | D10 | SPI SS, Analog Input (A10), PWM | SPI | digital-input, digital-output, analog-input, pwm | | D11 | Digital I/O, PWM | — | digital-input, digital-output, pwm | | D12 | Digital I/O, Analog Input (A11) | — | digital-input, digital-output, analog-input | | D13 | Onboard LED, PWM | — | digital-input, digital-output, pwm | | D14 | SPI MISO | SPI | digital-input, digital-output | | D15 | SPI SCK | SPI | digital-input, digital-output | | D16 | SPI MOSI | SPI | digital-input, digital-output | | A0 | Analog Input / Digital I/O | — | analog-input, digital-input, digital-output | | A1 | Analog Input / Digital I/O | — | analog-input, digital-input, digital-output | | A2 | Analog Input / Digital I/O | — | analog-input, digital-input, digital-output | | A3 | Analog Input / Digital I/O | — | analog-input, digital-input, digital-output | | A4 | Analog Input / Digital I/O | — | analog-input, digital-input, digital-output | | A5 | Analog Input / Digital I/O | — | analog-input, digital-input, digital-output | ## Available Software - **[Arduino IDE]()** (open-source) - **[PlatformIO]()** (open-source) ## Description ## Overview The Arduino Micro is the smallest Arduino board with built-in USB support, based on the ATmega32u4 microcontroller running at 16 MHz. Measuring just 48 × 18mm, it packs the core functionality of the Arduino Leonardo into a breadboard-compatible form factor, including native USB device emulation without a secondary USB-to-serial chip. The board provides 20 digital I/O pins (7 PWM-capable), 12 analog input channels, and hardware Serial, I2C, and SPI interfaces. A 6-pin ISP header is included for direct AVR programming. The micro USB port serves for both power delivery and programming. Onboard 3.3V regulation supports mixed-voltage peripherals, and a 3.3V pin provides up to 50mA. Like the Leonardo, the Micro can simultaneously appear to a host computer as a virtual serial port, USB mouse, and USB keyboard. This native USB HID capability is particularly valuable in compact installations where the board needs to interface with a computer without a dedicated microcontroller or host software. The Micro is not shield-compatible due to its compact form factor, but its breadboard-friendly pin layout and small footprint make it ideal for embedding in finished projects, wearables, and custom enclosures where space is a premium concern. ## Where to Buy - [Arduino Store (US)](https://openhardware.directory/r?to=https%3A%2F%2Fstore-usa.arduino.cc%2Fproducts%2Farduino-micro&ref=openhardware.directory&product=arduino-micro&source=md-export) — $21.80 - [Arduino Store (EU)](https://openhardware.directory/r?to=https%3A%2F%2Fstore.arduino.cc%2Fproducts%2Farduino-micro&ref=openhardware.directory&product=arduino-micro&source=md-export) — €24.10 - [DigiKey](https://openhardware.directory/r?to=https%3A%2F%2Fwww.digikey.com%2Fen%2Fproducts%2Fdetail%2Farduino%2FA000053%2F4486332&ref=openhardware.directory&product=arduino-micro&source=md-export) — $23.50 - [Mouser](https://openhardware.directory/r?to=https%3A%2F%2Fwww.mouser.com%2FProductDetail%2FArduino%2FA000053&ref=openhardware.directory&product=arduino-micro&source=md-export) — $23.50 - [Amazon US](https://openhardware.directory/r?to=https%3A%2F%2Fwww.amazon.com%2Fdp%2FB00AFY2S56&ref=openhardware.directory&product=arduino-micro&source=md-export) — $23.50 ## Resources - [product](https://openhardware.directory/r?to=https%3A%2F%2Fwww.adafruit.com%2Fproduct%2F1086&ref=openhardware.directory&product=arduino-micro&source=md-export) - [wiki](https://openhardware.directory/r?to=https%3A%2F%2Fdocs.arduino.cc%2Fhardware%2Fmicro&ref=openhardware.directory&product=arduino-micro&source=md-export) - [datasheet](https://openhardware.directory/r?to=https%3A%2F%2Fww1.microchip.com%2Fdownloads%2Fen%2FDeviceDoc%2FAtmel-7766-8-bit-AVR-ATmega16U4-32U4_Datasheet.pdf&ref=openhardware.directory&product=arduino-micro&source=md-export) ## Tags `arduino`, `atmega32u4`, `native-usb`, `usb-hid`, `breadboard-friendly`, `compact` ## Images ![Arduino Micro](https://nbg1.your-objectstorage.com/openhardware-directory/entities/arduino-micro/c48c866496c8.jpg) ![Arduino Micro](https://nbg1.your-objectstorage.com/openhardware-directory/entities/arduino-micro/d5935e472e7d.jpg) --- [View full device page](https://openhardware.directory/devices/arduino-micro)