Arduino compatibility was always on the wishlist for this project. However, when I started designing there was no suitable Arduino compatible microcontroller with the required connectivity and speed. MSP430 was a possible contender due to the wiring based Energia IDE, but it was lacking a bit in the memory department. In the end I decided to give up on the whole Arduino compatibility and go with an ARM M0 processor from a company called Nuvoton. The GNU ARM tools are free and open source after all. I also had some positive experience with the Cocox IDE on a previous project.

Just as I finished up the layout, Arduino announces the Arduino Zero, an ARM M0+ based board with all the connectivity I was looking for. Argh...

At the moment, the Atmel SAMD21 that is used on the zero is made of unobtanium so I decided to stick with the Nuvoton part for the initial prototypes. I will likely change it as soon as the Atmel part becomes available. In preparation for the swap, I snagged one of the few available development boards for the SAM D21 line. 

As far as I can tell it's functionally identical to the Zero, except that it's using the 64 pin part and has no header bringing out the debug interface for debugging target systems. I'm glad they fixed that major oversight on the Zero.