Hey there,

the final layout for HACK is 99,9% done; I only have to check if copper pours are connected to ground, and then I need to place fiducials markers around to ease the job of pick-n-place machines.

So far the mods made from the original idea and from JACK are here synthesized:

1. No more ATSAMR21, we're using the ATSAMD21E (32 pin)
2. Smaller LDO accounts for more PCB real estate
3. 2x13 pin headers, 1 additional pin connected to VDDANA (filtered analog power supply for sensitive analog applications)
4. Jumper on backside to connect LDO input to VUSB or to external pin (jumper closed: board is powered by USB; jumper opened: board is powered by VLDO pin)

Check out the github repo; more details about why no more SAMR21 will follow in the next days.

Cheers, Mick