Using an ATSAMD21G18A on my custom pcb. After much trail and error i found that i need to bootload my chips for them to be used. I bought a j-link to let me bootload them. Originally i wanted to use the adafruit feather .bin file, but it wouldn't work like: no device read id, or no memories, or would flash but die half way. So i used the samd .bin file given out by sparkfun website and that worked it would flash, verify itself, and be programmable. Though my problem is now that once i disconnect the j-link from the board i get a device cannot be read error, and everything falls apart. Wanted to know if anyone has any insight on what i can do.
Oh i also got chips bootloaded to what i want and placed them on my board, and nothing reads its like nothings there.