The ATSAMD21-XPRO evaluation kit is ideal for evaluating and prototyping with ATSAMD21J18A ARM Cortex-M0+ based microcontroller. The ATSAMD21J18A is a low power microcontrollers using the 32bit ARM Cortex- M0+ processor and ranging with up to 256KB flash and 32KB of SRAM. This device operate at a maximum frequency of 48MHz and reach 2.14 Coremark/MHz. Supported by the Atmel Studio integrated development platform, the kit provides easy access to the features of the ATSAMD21J18A and explains how to integrate the device in a custom design. The Xplained Pro microcontroller evaluation kit include an on-board embedded debugger and no external tools are necessary to program or debug the ATSAMD21J18A. The Xplained Pro extension kits offers additional peripherals to extend the features of the board and ease the development of custom designs.