Seeed Studio XIAO SAMD21 Arduino Microcontroller
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Description
The Seeed Studio XIAO SAMD21, which used to be named Seeeduino XIAO, is the first debut of the Seeed Studio XIAO family, a series of powerful thumb-size dev boards compatible with Arduino. It carries the powerful ATSAMD21G18A-MU which is a low-power microcontroller. On the other hand, this little board has good performance in processing but needs less power. It is designed in a tiny size and can be used for wearable devices and small projects.
Seeed Studio XIAO SAMD21 has 14 PINs, which can be used for 11 digital interfaces, 11 mock interfaces, 10 PWM interfaces (d1-d10), 1 DAC output pin D0, 1 SWD pad interface, 1 I2C interface, 1 SPI interface, 1 UART interface, Serial communication indicator (T/R), Blink light (L) through pin multiplexing. The colors of LEDs(Power, L,RX,TX) are green, yellow, blue, and blue. Moreover, Seeed Studio XIAO SAMD21 has a Type-C interface that can supply power and download code. There are two reset buttons, you can short-connect them to reset the board.
Documentations
There are two documents on the usage of Seeed Studio XIAO SAMD21 which focus on different areas, check the table below for reference:
Pinout Digram
Interface
Seeed Studio XIAO SAMD21 Getting Started
Seeed Studio XIAO SAMD21 with MicroSD Card(SPI)
Seeed Studio XIAO SAMD21 GPIO Usage
Seeed Studio XIAO SAMD21 with GPS(UART)
Seeed Studio XIAO SAMD21 Resources
Single Cycle IOBUS
CircuitPython on Seeed Studio XIAO SAMD21
Get started with CircuitPython on Seeed Studio XIAO SAMD21 .
Features
Powerful CPU: ARM® Cortex®-M0+ 32bit 48MHz microcontroller(SAMD21G18) with 256KB Flash,32KB SRAM.
Flexible compatibility: Compatible with Arduino IDE.
Easy project operation: Breadboard-friendly.
Small size: As small as a thumb(21x17.8mm) for wearable devices and small projects.
Multiple development interfaces: 11 digital/analog pins, 10 PWM Pins, 1 DAC output, 1 SWD Bonding pad interface, 1 I2C interface, 1 UART interface, 1 SPI interface.
Specifications
CPU
ARM Cortex-M0+ CPU(SAMD21G18) running at up to 48MHz
Flash Memory
256KB
SRAM
32KB
Digital I/O Pins
11
Analog I/O Pins
11
I2C interface
1
SPI interface
1
QTouch
7 (A0,A1,A6,A7,A8,A9,A10)
UART interface
1
Power supply and downloading interface
Type-C
Power
3.3V/5V DC
Dimensions
21×17.8×3.5mm
Hardware




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.
XIAO SAMD21 currently only supports battery power supply and cannot connect to Type-C while a battery is connected, as it may pose a safety risk.
Please pay attention to use, do not lift the shield cover.
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