---
product_id: 442638319
title: "Seeed Studio XIAO SAMD21: The Smallest Arduino Microcontroller, 100% Arduino IDE Compatible, Pre-Soldered, USB Type-C, Battery Included"
brand: "seeed studio"
price: "176 Lei"
currency: RON
in_stock: true
reviews_count: 5
category: "Seeed Studio"
url: https://www.desertcart.ro/products/442638319-seeed-studio-xiao-samd21-the-smallest-arduino-microcontroller-100-arduino
store_origin: RO
region: Romania
---

# 48MHz ARM Cortex-M0+ CPU 20mm x 17.5mm ultra-compact size USB Type-C interface Seeed Studio XIAO SAMD21: The Smallest Arduino Microcontroller, 100% Arduino IDE Compatible, Pre-Soldered, USB Type-C, Battery Included

**Brand:** seeed studio
**Price:** 176 Lei
**Availability:** ✅ In Stock

## Summary

> 🚀 Tiny Tech, Massive Impact: The Ultimate Microcontroller for Next-Gen Makers

## Quick Answers

- **What is this?** Seeed Studio XIAO SAMD21: The Smallest Arduino Microcontroller, 100% Arduino IDE Compatible, Pre-Soldered, USB Type-C, Battery Included by seeed studio
- **How much does it cost?** 176 Lei with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.ro](https://www.desertcart.ro/products/442638319-seeed-studio-xiao-samd21-the-smallest-arduino-microcontroller-100-arduino)

## Best For

- seeed studio enthusiasts

## Why This Product

- Trusted seeed studio brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Versatile I/O Arsenal:** 14 GPIO pins supporting analog, digital, PWM, DAC, I2C, UART, and SPI for limitless project possibilities.
- • **Blazing Fast Processing:** Experience 3x the speed of classic Arduino with a 48MHz ARM Cortex-M0+ core.
- • **Future-Ready USB Type-C:** Modern USB-C port for power and programming, enabling HID device creation and smooth connectivity.
- • **Pocket-Sized Powerhouse:** Fits in the palm of your hand at just 20mm x 17.5mm—perfect for sleek, wearable tech.
- • **Seamless Arduino IDE Compatibility:** Plug-and-play with the full Arduino ecosystem for rapid prototyping and coding ease.

## Overview

The Seeed Studio XIAO SAMD21 is the smallest Arduino-compatible microcontroller board, featuring a powerful 48MHz ARM Cortex-M0+ CPU, 256KB flash memory, and 32KB SRAM. Despite its ultra-compact 20mm x 17.5mm size, it offers 14 multifunctional GPIO pins, including analog, digital, PWM, DAC, I2C, UART, and SPI interfaces. Equipped with a USB Type-C port and battery support, it’s ideal for wearable devices, rapid prototyping, and advanced DIY projects, all fully compatible with the Arduino IDE for seamless development.

## Description

Take a look at Seeeduino XIAO(Pre-Soldered). What a small size and cute looking! It is the smallest member of the Seeeduino family. Seeeduino XIAO(Pre-Soldered) still carries the powerful CPU-ARM Cortex-M0+(SAMD21G18) which is a low-power Arduino microcontroller. On the other hand, this little board has good performance in processing but needs less power. As a matter of fact, it is designed in a tiny size and can be used for Arduino wearable devices and small projects.Apart from the strong CPU, Seeeduino XIAO(Pre-Soldered) is excellent in many other functions. It has 14 GPIO PINs, which can be used for 11 analog PINs, 11 digital PINs, 1 I2C interface, 1 UART interface, and 1 SPI interface. Some PINs have various functions, A1/D1 to A10/D10 Pins have PWM functions and Pin A0/D0 has a function of DAC which means you can get true analog signals not PWM signals when you define it as an analog pin, that’s why 14 GPIO PINs can realize more I/O PINs and interfaces. Moreover, Seeeduino XIAO(Pre-Soldered) supports the USB Type-C interface which can supply power and download code. There are power pads at the back of the XIAO which support battery and make it designed for wearable devices to become realistic. Except for the power LED, we add a user LED on board for your better coding experience. Usually a Dev. Board as small as this size will use the chip’s inner crystal oscillator for time fixing, in order to make the clock more accurate, Seeeduino XIAO(Pre-Soldered) layouts an extra 32.768KHz to make the clock more stable.

Review: I bought 3 of these a couple years ago to play around with. At the time, it was just because they were cheap and quick to get on desertcart. I quickly fell in love. Though they aren't perfect. Pros: Size. They're tiny. Even 2 years on, most microcontrollers are *at least* 2 to 4 times the size. The small size makes them easy to fit into almost any project. They're literally the size of a postage stamp. I can cover one with my finger. Which brings me to the next pro: I/O. Even at this tiny size, you still have tons of I/O, with support for hardware interrupts, UART, I2C, SPI, and true analog pins with DAC. The big one for me, though, is HID support through the USB type C port. That's a much less common feature than you'd think. If you want to make devices that can talk to other devices as an input device, you need this. Speed. You don't really think that a simple Arduino device needs to be fast, but having a 48mhz processor and 32mb of SRAM to work with open up a LOT of possibilities. Take, for example, my most recent project. I wanted to make a vintage laptop keyboard work with a modern laptop motherboard. But I wanted to do so without damaging the original keyboard. So to interface the two, I needed the Xiao to be able to read the PS/2 protocol that the keyboard was talking in, and give USB HID protocol commands to the computer. Reading the PS/2 protocol takes very precise timing. Your code has to execute within a certain number of microseconds, otherwise the command will fail. Because of the speed of the processor, I could have more code executing in the interrupts while still staying under the threshold. Cons: Storage. While I've never run up against the limit, the Xiao has 256 kB of flash memory. That's not the smallest, but it's certainly not the biggest I've seen on a microcontroller. So I do get a little nervous when I start importing a bunch of libraries. So far, my most involved project, the keyboard that I talked about earlier, only uses about 25% of that storage. And that's importing two different libraries plus my custom code. But if you have a large project that takes many libraries or a whole lot of code, you might run into problems with storage. Bootloader Corruption. I've only had it happen once and it was after hundreds upon hundreds of code uploads. These guys saying they're bricking after 50 uploads have to be doing something wrong. Or maybe it's because they're on Mac hardware, I don't know. But I've had to upload 50 times pretty much everyday I've worked on this project and so far it's not been a problem. But like I said, I did have one of my original three stop responding to USB. So the problem does exist. The device itself still does what the last upload of code told it to do, but I can no longer get it to talk with the Arduino software. And resetting the unit didn't resolve it. So you're mileage may vary.
Review: Very satisfied with the purchase, all 3 SAMD21 board tested and confirmed working. I will be able to prototype easily with these spare boards

## Features

- 🌱【Powerful CPU】 The XIAO is equipped with an ARM Cortex-M0+ 32bit 48MHz microcontroller, which is three times faster than Arduino Uno and Arduino Nano. Furthermore, this Arduino IDE compatible board Xiao has 256KB flash memory and 32KB SRAM.
- 🌱【Rich Interfaces in a Tiny Size】 The device has 14 GPIO pins, each of which has 11 analog channels, 11 digital channels, I2C*1, UART*1, and SPI*1, USB Type-C interface*1 in a tiny space, just 20mm*17.5mm (about the size of your thumb). Seeeduino XIAO is the smallest Arduino compatible board in the Seeeduino series.
- 🌱【Fully compatible with Arduino IDE】 Seeed Studio XIAO development board is perfectly compatible with Arduino IDE and you can easily create small projects using the extensive and comprehensive Arduino library. It has a 2.54mm pin pitch and can be used even when inserted into a breadboard because it is an Arduino microcontroller.It has a 2.54mm pin pitch and can be used even when inserted into a breadboard because it is an Arduino microcontroller.
- 🌱【Applications】 Seeed Studio XIAO is suitable for Wearable devices, Rapid prototyping, DIY keyboard, USB to multi-channel TTL/USB host mode, etc.
- 🌱【Perfect for Wearable and Tiny Arduino Projects】 This microcontroller has good performance in processing but needs less power. As a matter of fact, it is designed in a tiny size and can be used for Arduino wearable devices and small projects.

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B0B15B869W |
| Best Sellers Rank | #36,866 in Computers ( See Top 100 in Computers ) #495 in Single-Board Computers |
| Manufacturer | seeed studio |
| Product Dimensions | 2 x 1.75 x 1.75 cm; 5 g |

## Product Details

- **Brand:** Seeed Studio
- **CPU model:** MediaTek MT8125
- **Installed RAM memory size:** 32 GB
- **Memory storage capacity:** 256 KB
- **Model name:** XIAO SAMD21

## Images

![Seeed Studio XIAO SAMD21: The Smallest Arduino Microcontroller, 100% Arduino IDE Compatible, Pre-Soldered, USB Type-C, Battery Included - Image 1](https://m.media-amazon.com/images/I/51iZsB9hwpL.jpg)
![Seeed Studio XIAO SAMD21: The Smallest Arduino Microcontroller, 100% Arduino IDE Compatible, Pre-Soldered, USB Type-C, Battery Included - Image 2](https://m.media-amazon.com/images/I/61G3BFXtwuL.jpg)
![Seeed Studio XIAO SAMD21: The Smallest Arduino Microcontroller, 100% Arduino IDE Compatible, Pre-Soldered, USB Type-C, Battery Included - Image 3](https://m.media-amazon.com/images/I/61K3hPTvfGL.jpg)
![Seeed Studio XIAO SAMD21: The Smallest Arduino Microcontroller, 100% Arduino IDE Compatible, Pre-Soldered, USB Type-C, Battery Included - Image 4](https://m.media-amazon.com/images/I/61c+usZyg3L.jpg)
![Seeed Studio XIAO SAMD21: The Smallest Arduino Microcontroller, 100% Arduino IDE Compatible, Pre-Soldered, USB Type-C, Battery Included - Image 5](https://m.media-amazon.com/images/I/61xvNg+KZgL.jpg)

## Available Options

This product comes in different **Size** options.

## Questions & Answers

**Q: Can i attach voltage in to the 5v pin? i'm trying to put this on a pcb. will it have the same voltage regulation?**
A: As a previous contributor wrote: a lot of people answering questions here do not know what they are talking about! So here is the answer copied straight from the Seeed Studio webpage regarding this board:
"Note
For general I/O pins: Working voltage of MCU is 3.3V . Voltage input connected to general I/O pins may cause chip damage if it' higher than 3.3V .
For power supply pins: The built-in DC-DC converter circuit able to change 5V voltage into 3.3V allows to power the device with a 5V supply via VIN-PIN and 5V-PIN.
Please pay attention to use, do not lift the shield cover."

**Q: Does this come with a bootloader or not?**
A: yes - I'm pretty sure it does.  Its been a while since I played with it.  But I seem to recall all was needed was to download the necessary Arduino files into the Arduino programming system and make the correct connection to the device.   However be aware the device is finicky in that it needs to be rebooted for programming mode using a jumper wire.  So if you're doing a lot of development/debugging, do that work in a standard Arduino first, and then translate your  debugged program to this device.

**Q: Is the IO 5V tolerant?**
A: From the testing I have done on mine, the pins when being used as an input, are 3.3v tolerant.

**Q: The board can be connected to 5V power supply and simultaneously been conectes to the usb conector from my computer?**
A: There would be a problem if the 5V supply was actually a lower voltage than the USB (which should be 5V). A diode protects everything if the external 5V supply was above 5V (up to the 6V limit of the voltage regulator on the board). To be safe, a diode should be added in series with the external 5V supply. This protection is present in genuine Arduino boards' VIN pin.

## Customer Reviews

### ⭐⭐⭐⭐⭐ Review
*by R***S on 10 May 2021*

I bought 3 of these a couple years ago to play around with. At the time, it was just because they were cheap and quick to get on Amazon. I quickly fell in love. Though they aren't perfect. Pros: Size. They're tiny. Even 2 years on, most microcontrollers are *at least* 2 to 4 times the size. The small size makes them easy to fit into almost any project. They're literally the size of a postage stamp. I can cover one with my finger. Which brings me to the next pro: I/O. Even at this tiny size, you still have tons of I/O, with support for hardware interrupts, UART, I2C, SPI, and true analog pins with DAC. The big one for me, though, is HID support through the USB type C port. That's a much less common feature than you'd think. If you want to make devices that can talk to other devices as an input device, you need this. Speed. You don't really think that a simple Arduino device needs to be fast, but having a 48mhz processor and 32mb of SRAM to work with open up a LOT of possibilities. Take, for example, my most recent project. I wanted to make a vintage laptop keyboard work with a modern laptop motherboard. But I wanted to do so without damaging the original keyboard. So to interface the two, I needed the Xiao to be able to read the PS/2 protocol that the keyboard was talking in, and give USB HID protocol commands to the computer. Reading the PS/2 protocol takes very precise timing. Your code has to execute within a certain number of microseconds, otherwise the command will fail. Because of the speed of the processor, I could have more code executing in the interrupts while still staying under the threshold. Cons: Storage. While I've never run up against the limit, the Xiao has 256 kB of flash memory. That's not the smallest, but it's certainly not the biggest I've seen on a microcontroller. So I do get a little nervous when I start importing a bunch of libraries. So far, my most involved project, the keyboard that I talked about earlier, only uses about 25% of that storage. And that's importing two different libraries plus my custom code. But if you have a large project that takes many libraries or a whole lot of code, you might run into problems with storage. Bootloader Corruption. I've only had it happen once and it was after hundreds upon hundreds of code uploads. These guys saying they're bricking after 50 uploads have to be doing something wrong. Or maybe it's because they're on Mac hardware, I don't know. But I've had to upload 50 times pretty much everyday I've worked on this project and so far it's not been a problem. But like I said, I did have one of my original three stop responding to USB. So the problem does exist. The device itself still does what the last upload of code told it to do, but I can no longer get it to talk with the Arduino software. And resetting the unit didn't resolve it. So you're mileage may vary.

### ⭐⭐⭐⭐⭐ Review
*by N***N on 11 May 2024*

Very satisfied with the purchase, all 3 SAMD21 board tested and confirmed working. I will be able to prototype easily with these spare boards

### ⭐⭐⭐⭐⭐ Review
*by S***N on 27 September 2023*

Super petit très content : ) !

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*Product available on Desertcart Romania*
*Store origin: RO*
*Last updated: 2026-03-12*