All of a sudden my AtmelICE refuses to connect to the ATSAML21E18B on SWD, works fine on my ATUC256L4U aWire. My setup has been working fine for well over a year at this point - but it decided to stop for some reason. I tested two separate ICEs with two separate boards. The firmware is up and running and I can see my LED blinking at 1 Hz as it ought to. On Friday I managed to re-flash the device with some firmware by adding a 3.3k pull-up resistor on the clock line (3.3V) but now that won't work either.
I tried re-installing Atmel Studio too - no luck there.
I found and old thread where somebody suggested checking that the RESET line is not floating at an undefined value. I am WFH today so I only have access to my hobbyist kit of crappy resistors and I added a 1.5k+1.5k+330 pull-up resistor (with God knows what tolerance values) on the RESET line but that doesn't seem to be helping - now instead what happens is that the mcu resets when I try to read the device signature - this seems to suggest that the RESET line is pulled low when I'm trying to read the device signature. Does anyone recognize this behavior? Any suggestions?
This is very strange as this setup has been stable and functional for well over a year at this point. Don't you just hate electronics ?