Atmel Studio 7.0.2397 on Win7-Pro;
same (mis-)behaviour in Microchip Studio 7.0.2542 on Win10-Pro.
The SAML21 XPlained-Pro is seen:
but when I press 'Connect', nothing happens. The button goes down when I click it, but just comes up again immediately when I release - still saying 'Connect'
The 'Status' LED on the board blinks a couple of times, then goes steady-on.
With an ATmega4809 XPlained Pro, the button immediately changes to 'Disconnect', and is greyed-out while "searching for protocols":
(while 'searching', the 'Status' LED is flashing fast)
So why doesn't this work with the L21 board?
I couldn't see anything on the L21 XPlained-Pro page about firmware updates or anything:
The info panel suggests these interfaces should be present: