DEV-13664 SparkFun SAMD21 Mini Breakout

The SAMD21 Mini Breakout is a powerful, compact (Pro Mini-sized) breakout based on Atmel ATSAMD21G18; a 32-bit ARM Cortex-M0+ processor with 256KB flash, 32KB SRAM, and an operating speed of up to 48MHz. This board can be used as a breakout for ATSAMD21G18 controller to explore it’s the features. The charm and convenience of Arduino IDE and hardware options makes it an excellent choice, solving the problems of low storage limits and dynamic memory stack overflows that have plagued the previous iterations of the Arduino family.
The onboard micro-B USB Port can be used to power as well as program. One of the most unique features of the SAMD21 is SERCOM a set of six configurable serial interfaces that can be turned into either a UART, I2C master, I2C slave, SPI master, or SPI slave.
Key Features:

ATSAMD21G18 32-bit/48MHz ARM Cortex-M0+
256KB Flash Memory
32KB SRAM
32KB of EEPROM (emulated in Flash)
22 GPIO Count
14 ADC Channels at 12-bit Resolution
Analog-to-Digital and Digital-to-Analog Converters (ADC & DAC)
RAW: 3.5V-6.0V
VCC: 600mA @3.3V
Pro Mini/Micro Layout
Integrated USB Controller

Relevant Resources:

Schematic
Eagle Files
Hookup Guide
Graphical Datasheet
Datasheet(ATSAMD21G18)
GitHub(Design Files)