This board breaks out all the pins of the Cortex M0 SAMD21G18A. It has a debug header, micro USB connector, and on-board LiPo charging support. I initially designed this board to practice with the SAMD21 as well as to use it as a base for future projects. Read about it's development here: http://westsideelectronics.com/arduino-m0-breakout-board-2/ This board is compatible with either Adafruit's or Sparkfun's bootloader for Arduino. Suggestions and comments are welcome!
Full schematics and EAGLE files are provided in the Files Section.
I originally ordered the black silkscreen but the blue silkscreen from PCBway looks absolutely beautiful. I also made the lines 90/45 so it looks especially neat.
Thinking back I think that the lipo charging was not required since I don't use it that all often. Not at all in fact. I think the next iteration of this board is to make a version that fits nicely onto the breadboard like a DIP chip but with the bare minimum of an oscillator, caps, and a voltage regulator.
This was a board that I put together in eagle as a foundation board for all my future projects. While the breadboard compatible layout is convenient, it would make the board quite long in this case. Female to male jumper wires is a good alternative, and there is less incentive to let it sit on the breadboard taking up valuable space.
I finally figured out how to tent vias, and the board looks absolutely gorgeous compared to the first few iterations.