Datasheet

Here's some handy specs!

Measures 2.8" x 2.1" x 0.28"

ATSAMD21G18 @ 48MHz with 3.3V logic/power

256KB of FLASH + 32KB of RAM

4 MB SPI Flash chip

No EEPROM

32.768 KHz crystal for clock generation & RTC

3.3V regulator with 500mA peak current output

USB native support, comes with USB bootloader and serial port debugging

You also get tons of pins - 25 GPIO pins, 5 more than the Metro 328

Hardware Serial, hardware I2C, hardware SPI support

PWM outputs on almost all pins

6 x 12-bit analog inputs

1 x 10-bit analog output (DAC)

Built in NeoPixel on pin #40

Pin #13 red LED for general purpose blinking

Power on/off switch

4 mounting holes

We also include 4 rubber bumpers to keep it from slipping off your desk

Reset button