So I have a "blinky" demo (the "hello world" of embedded?) up and running on github, which I've tested on an Adafruit Feather M0 board: <https://github.com/auxym/nim-on-samd21>
The [DFLL clock initialization code](https://github.com/auxym/nim-on-samd21/blob/e7e8c3b993fca3e2ca3ebe9ff430959c73075149/src/clocks.nim#L5) was a good test for svd2nim and uncovered some bugs and inconsistencies, which were fixed.
