Seeed Studio XIAO SAMD21 Cortex M0+ (Seeeduino XIAO)
Seeed Studio XIAO SAMD21 Cortex M0+ (Seeeduino XIAO) has a 5-10 day lead time before dispatch. Order will only be sent once all items are available for delivery.
Seeed Studio XIAO SAMD21 Cortex M0+ (Seeeduino XIAO)
The original XIAO. Launched in 2019, the Seeed Studio XIAO SAMD21 (also known as the Seeeduino XIAO) is the board that started the XIAO family and set the standard for what a thumb-sized dev board could do. At just 21 x 17.8mm, it packs a full ARM Cortex-M0+ processor, native USB, and an 11-pin analog/digital I/O footprint into a form factor small enough to disappear inside a wearable, keychain, or tight enclosure.
This board ships with headers not fitted, giving you the flexibility to solder your own headers, wires, or castellated mounting depending on your project. Need it ready to plug straight into a breadboard or Grove module? Grab the pre-soldered version instead.
Why Choose the XIAO SAMD21?
- Beginner-friendly, no shortcuts on capability - native Arduino IDE support means you're writing real code and running real projects from your first upload, backed by free courses, tutorials, and a large community of reference projects.
- Tiny footprint, full feature set - 14 GPIO pins, 11 analog pins, DAC, I2C, UART, and SPI, all packed onto a board smaller than a 20-cent coin.
- Massive expansion ecosystem - drop straight into the XIAO Expansion Board, Grove system (400+ compatible modules), CAN-Bus and LoRa modules, LED matrices, ePaper and round displays, mmWave sensors, GPS modules, mic arrays, and more - no soldering or prior electronics experience required to start prototyping.
- Multi-platform software support - Arduino, PlatformIO, MicroPython, CircuitPython, and Zephyr are all supported, so the board grows with you as your skills do.
- Built to last - rated for a -40°C to 85°C working range, making it just as suited to outdoor or enclosure-mounted projects as desktop prototyping.
Ideal For
Wearables, compact IoT sensors, USB HID devices, battery-powered projects, and anyone who wants the full Arduino experience without the footprint of a full-size Uno or Nano.
Specifications
| Chipset | Microchip SAMD21G18 |
| Processor | ARM Cortex-M0+ @ up to 48 MHz |
| RAM | 32KB SRAM |
| Flash | 256KB |
| GPIO | 14 pins (11 digital, 11 analog) |
| Other Interfaces | 1x DAC, 1x I2C, 1x UART, 1x SPI |
| Onboard | User LED, Power LED, TX/RX status LEDs |
| Power Input | 5V via USB Type-C or BAT |
| Max Output | 5V @ 500mA, 3.3V @ 200mA |
| Software | Arduino, PlatformIO, MicroPython, CircuitPython, Zephyr, and more |
| Working Temperature | -40°C to 85°C |
| Dimensions | 21 x 17.8mm |
Pinout
Learn More
Full setup guides, pinout diagrams, and project examples are available on the Seeed Studio Wiki.
Looking to expand your build? Check out our full range of XIAO Expansion & Breakout Boards.
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