I have been trying to connect to the Zero board via the SWD connector using a Atmel JTAGICE3 adapter. It can't find the chip (error 4109). I soldered in a header and connected the ribbon cable. Has anyone made this connection work?
BTW, the JTAGICE3 does work ok with the Uno and ICSP adapter (under Studio of course).
I want to used the SWD interface to experiment with the zero and confirm I can make my own SamD21 based boards with SWD interface for programming.