Outstanding RF performance - Powered by SAMD21G18 chip, operating up to 48MHz, equipped with 32KB of , and 256KB of onboard flash memory. Rich Interface - 11x analog / 11x digital Pins, 1x I2C interface, 1x UART port, and 1 SPI port. Thumb-size Design - 21 x 17.5mm, XIAO series classic form-factor, suitable for wearable devices. Multiple Develop Platform - Support for / Micropython / CircuitPython development, friendly for beginners, satisfied for electronics enthusiasts. Perfect for Production - Breadboard-friendly & SMD design, no components on the back. Application: Wearable devices. Rapid prototyping (directly attached to the expanded PCB as a minimal system). Perfect for all the projects that need a mini for . DIY keyboard. USB development (USB to multi-channel TTL/USB host mode, etc.) In a scenario where you need to read multiple mock values The output. Notes: The pins are not included in this product. Due to different product batches, the appearance , which does not affect the use. XIAO SAMD21 carries the powerful CPU-ARM -M0+(SAMD21G18) running at up to 48Hz.In addition to the powerful CPU,it has 256KB Flash and 32KB on board and supports the USB Type-C interface which can supply power and download code. XIAO SAMD21 has 14 PINs, which can be used for 11 digital interfaces,11 mock interfaces,10 PWM interfaces (-d10),1 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, XIAO SAMD21 has a Type-C interface which can supply power and download code.There are two reset button, you can short connect them to reset the board. Except for thepower LED, we add a user LED on board for your better coding experience. Usually, a dev board as small as this size use the chip's inner crystal oscillator fixing,in order to make the clock more accurate, XIAO SAMD21 layouts an extra 32.768KHz to make the clock more stable. Moreover, XIAO SAMD21 is friendly to the communities for its strong software compatibilities,which supports for ,for Micropython, and for CircuitPython. Except for the software, flexible I/O allows it to speak to almost any external device. Material:PC Package Contents: 1 * development board